10(user's guide)

5.0USER�S GUIDE

PRO/II 5.0 USER�S GUIDE The software described in this guide is furnished under alicense agreement and may be used only in accordancewith the terms of that agreement.

Information in this document is subject to change withoutnotice. Simulation Sciences Inc. assumes no liability forany damage to any hardware or software component or anyloss of data that may occur as a result of the use of theinformation contained in this manual.

Copyright Notice Copyright © 1997 Simulation Sciences Inc. All RightsReserved. No part of this publication may be copied and/ordistributed without the express written permission ofSimulation Sciences Inc., 601 S. Valencia Avenue, Brea, CA92823, USA.

Trademarks PRO/II is a registered mark of Simulation Sciences Inc.SIMSCI is a service mark of Simulation Sciences Inc.Windows is a trademark of Microsoft Corporation.Excel is a trademark of Microsoft Corporation.AutoCAD is a trademark of AutoDesk, Inc.

Printed in the United States of America.

Table of ContentsChapter 1 Using PRO/II

Starting PRO/II. . . . . . . . . . . . . . . . . . . . . . . . 1-1Compatibility with Previous Versions. . . . . . . . . . . . 1-2PRO/II Main Window Components. . . . . . . . . . . . . 1-4Manipulating the PRO/II Window. . . . . . . . . . . . . . 1-5Working with On-Screen Color Coding Cues. . . . . . . . 1-6Using the Menus. . . . . . . . . . . . . . . . . . . . . . . 1-6Using the Floating Palettes. . . . . . . . . . . . . . . . . . 1-9Using the Toolbar Buttons. . . . . . . . . . . . . . . . . . 1-9Using the PRO/II Main Window. . . . . . . . . . . . . .1-13

Chapter 2 Simulation BasicsGeneral Approach. . . . . . . . . . . . . . . . . . . . . . . 2-1Building the Flowsheet. . . . . . . . . . . . . . . . . . . . 2-3Required Data. . . . . . . . . . . . . . . . . . . . . . . . . 2-4Default Data. . . . . . . . . . . . . . . . . . . . . . . . . . 2-6Optional Data. . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Chapter 3 Managing PFD FilesOpening a New Simulation. . . . . . . . . . . . . . . . . . 3-1Opening an Existing Simulation. . . . . . . . . . . . . . . 3-2Saving the Current Simulation. . . . . . . . . . . . . . . . 3-2Closing a Simulation. . . . . . . . . . . . . . . . . . . . . 3-4Deleting a Simulation. . . . . . . . . . . . . . . . . . . . . 3-4Copying a Simulation. . . . . . . . . . . . . . . . . . . . . 3-5Importing a PRO/II Keyword Input File. . . . . . . . . . . 3-7Exporting Simulation Data to a PRO/II Keyword File. . . 3-10Using the Spreadsheet Tools. . . . . . . . . . . . . . . .3-11Exporting the Flowsheet Drawing to the Clipboard. . . . 3-12Exporting Stream Property Table Data. . . . . . . . . . . 3-12Copying Stream Property Table Data to the Clipboard. . . 3-13Exporting the PFD to an AutoCAD or PostScript File. . . 3-13

PRO/II User's Guide Table of Contentsi

Chapter 4 Building a FlowsheetSetting Simulation Preferences. . . . . . . . . . . . . . . . 4-1Placing a Unit on the Flowsheet. . . . . . . . . . . . . . .4-12Drawing Streams. . . . . . . . . . . . . . . . . . . . . .4-15Searching for a Unit or Stream. . . . . . . . . . . . . . .4-18Changing the Flowsheet Layout. . . . . . . . . . . . . . .4-18Drawing Freehand Objects. . . . . . . . . . . . . . . . .4-20

Chapter 5 Manipulating ObjectsSelecting Objects or Groups of Objects. . . . . . . . . . . 5-1Resizing an Object. . . . . . . . . . . . . . . . . . . . . . 5-3Rearranging Objects or Groups of Objects. . . . . . . . . . 5-5Editing Text. . . . . . . . . . . . . . . . . . . . . . . . . . 5-6

Chapter 6 Viewing Flowsheet ContentsScrolling the PFD. . . . . . . . . . . . . . . . . . . . . . . 6-1Zooming. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1Opening Multiple Viewport Windows. . . . . . . . . . . . 6-2Redraw the Simulation. . . . . . . . . . . . . . . . . . . . 6-3Panning. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

Chapter 7 Data Entry WindowsDefining the Simulation . . . . . . . . . . . . . . . . . . . 7-1Data Entry Windows for Unit Operations. . . . . . . . . . 7-9

Chapter 8 Specifying Component, Thermodynamic and Stream DataComponent Data. . . . . . . . . . . . . . . . . . . . . . . 8-1Assay Data . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8Thermodynamic Data. . . . . . . . . . . . . . . . . . . .8-11Stream Data. . . . . . . . . . . . . . . . . . . . . . . . .8-22Refinery Inspection and User-defined Properties. . . . . . 8-34BVLE (Validating Equilibrium Data). . . . . . . . . . . . 8-43

Chapter 9 Unit Operations and Utility ModulesCALCULATOR . . . . . . . . . . . . . . . . . . . . . . . . 9-2

FORTRAN Statements. . . . . . . . . . . . . . . . . 9-6Sample Calculator Procedures. . . . . . . . . . . . . 9-14

COLUMN, BATCH . . . . . . . . . . . . . . . . . . . . .9-18COLUMN, DISTILLATION . . . . . . . . . . . . . . . .9-19COLUMN, LIQUID-LIQUID EXTRACTION . . . . . . 9-34

Table of Contents PRO/II User's Guideii

COLUMN, SIDE . . . . . . . . . . . . . . . . . . . . . .9-39COMPRESSOR. . . . . . . . . . . . . . . . . . . . . . .9-42CONTROLLER . . . . . . . . . . . . . . . . . . . . . . .9-46CRYSTALLIZER . . . . . . . . . . . . . . . . . . . . . .9-48CYCLONE. . . . . . . . . . . . . . . . . . . . . . . . . .9-51DEPRESSURING UNIT. . . . . . . . . . . . . . . . . .9-57DISSOLVER. . . . . . . . . . . . . . . . . . . . . . . . .9-62EXPANDER . . . . . . . . . . . . . . . . . . . . . . . .9-63FLASH. . . . . . . . . . . . . . . . . . . . . . . . . . . .9-65FLASH WITH SOLIDS. . . . . . . . . . . . . . . . . . .9-69FLOWSHEET OPTIMIZER . . . . . . . . . . . . . . . .9-70HEAT EXCHANGER, LNG . . . . . . . . . . . . . . . .9-75HEAT EXCHANGER, RIGOROUS. . . . . . . . . . . . 9-77HEAT EXCHANGER, SIMPLE . . . . . . . . . . . . . .9-85HEATING/COOLING CURVES. . . . . . . . . . . . . .9-89MIXER. . . . . . . . . . . . . . . . . . . . . . . . . . . .9-93MULTIVARIABLE CONTROLLER . . . . . . . . . . . . 9-94PHASE ENVELOPE . . . . . . . . . . . . . . . . . . . .9-97PIPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-99POLYMER REACTOR . . . . . . . . . . . . . . . . . .9-104PROCEDURE DATA . . . . . . . . . . . . . . . . . . .9-105PUMP. . . . . . . . . . . . . . . . . . . . . . . . . . . .9-113REACTION DATA . . . . . . . . . . . . . . . . . . . . .9-114REACTOR . . . . . . . . . . . . . . . . . . . . . . . . .9-118REACTOR, BATCH . . . . . . . . . . . . . . . . . . . .9-128SOLID SEPARATOR . . . . . . . . . . . . . . . . . . .9-129SPLITTER . . . . . . . . . . . . . . . . . . . . . . . . .9-130STREAM CALCULATOR . . . . . . . . . . . . . . . .9-132SPEC/VARY/DEFINE. . . . . . . . . . . . . . . . . . .9-135USER-ADDED UNIT OPERATIONS . . . . . . . . . . 9-151

ELECTROLYTE MODULE . . . . . . . . . . . . . 9-157SIMSCI ADD-ON MODULES. . . . . . . . . . . . 9-160

VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . .9-163WIPED FILM EVAPORATOR . . . . . . . . . . . . . .9-164

PRO/II User's Guide Table of Contentsiii

Chapter 10 Running and Viewing a FlowsheetUsing the Run Palette. . . . . . . . . . . . . . . . . . . .10-1Checking the Simulation Status. . . . . . . . . . . . . . .10-3Understanding the Unit Color Coding Cues. . . . . . . . 10-4Running the Simulation. . . . . . . . . . . . . . . . . . .10-4Viewing Calculation History. . . . . . . . . . . . . . . .10-8Viewing Results. . . . . . . . . . . . . . . . . . . . . . .10-8Viewing Results in Stream Property Tables. . . . . . . . . 10-8Running a Case Study. . . . . . . . . . . . . . . . . . .10-11Viewing Case Study Results. . . . . . . . . . . . . . . .10-13Running Files in Batch Mode. . . . . . . . . . . . . . .10-13

Chapter 11 Printing and PlottingDefining Output Format . . . . . . . . . . . . . . . . . .11-1Generating a Report. . . . . . . . . . . . . . . . . . . . .11-6Viewing a Report . . . . . . . . . . . . . . . . . . . . . .11-6Printing a Report. . . . . . . . . . . . . . . . . . . . . . .11-7Plotting. . . . . . . . . . . . . . . . . . . . . . . . . . . .11-7The Plot Viewer . . . . . . . . . . . . . . . . . . . . . .11-10Setting Up the Printer. . . . . . . . . . . . . . . . . . .11-11Printing a Flowsheet Layout. . . . . . . . . . . . . . . .11-11

Chapter 12 Customizing the PFD WorkplaceChanging Unit Style. . . . . . . . . . . . . . . . . . . . .12-1Changing Stream Style. . . . . . . . . . . . . . . . . . .12-3Modifying Drawing Preferences. . . . . . . . . . . . . .12-9Specifying a Default Editor. . . . . . . . . . . . . . . . .12-9Changing the Default Font. . . . . . . . . . . . . . . . .12-10

Index

Table of Contents PRO/II User's Guideiv

Chapter 1Using PRO/II

This chapter describes how to start and exit PRO/II. In addition, it reviewssome basic Windows features as they appear in PRO/II and brieflydescribes how to use them.

Starting PRO/IIIf you have not yet installed PRO/II on your system, see thePRO/IIPC/LAN Installation Guide.

If you do not see a PRO/II icon in a SIMSCI group window or in yourProgram/SIMSCIStart menu, see the troubleshooting section in thePRO/II PC/LAN Installation Guide.

To start PRO/II:

➤ Double-click on the PRO/II icon or launch from the Start menu.The PRO/II welcome window appears. This window contains infor-mation on opening files and on the color codes used in the program.

Figure 1-1: The PRO/II Welcome Window

➤ Click OK to exit the window. The PRO/II main window willappear.

PRO/II User's Guide Chapter 1 Using PRO/II1-1

Figure 1-2: The PRO/II Main Window

You can now open a new simulation file (selectFile/New), open anexisting file (selectFile/Open), or import a keyword file (selectFile/Import). SeeChapter 3, Managing PFD Files, for additionaldetails.

Compatibility with Previous VersionsPRO/II v4.1/4.13/4.15/4.17 simulation files arenot compatible withthis release of PRO/II. You must use theSimulation File Converterprogram to convert these files. If you attempt to open one of thesesimulation files before you have used theSimulation File Converter,you will receive a message indicating that the file was created using thewrong version of PRO/II and asking you to convert the files.

Note: Before using the file converter, make a copy of the database filesto be converted. Work only on the copies. In this way you will eliminateany possibility of corrupting your original files.

To convert a PRO/II v4.1/4.13/4.15/4.17 simulation file:➤ Run theSimulation File Converterprogram (FILCVT.EXE) by

double-clicking on its icon in the SIMSCI program group (NT3.51)or selectPrograms/Simsci/Simulation File Converterfrom the Startmenu (Win95/NT4.0).

Chapter 1 Using PRO/II PRO/II User's Guide1-2

The original databases files have the extensions .PR0, PR1, .PR2, .PR3,and .SFD. Some of these files may not exist for every problemdatabase. The file converter converts these files to the new databasestructure used by the current release of PRO/II and replaces the old.PR* files with new ones. These newly converted files arenotcompatible with earlier versions of PRO/II.

As a safety measure, theSimulation File Converteralso copies theoriginal database files and saves them with the extensions .SV0, .SV1,.SV2, .SV3, and .SVS. These filesare compatible with the earlierversion of PRO/II. However, before they can be used, their old exten-sions must be restored to .PR0, PR1, .PR2, .PR3, and .SFD,respectively.

Note: Some keyword input files that were created manually may includefeatures that are not supported by the PRO/II graphical user interface.PRO/II issues a warning when this occurs. For flowsheet execution, allfeatures will be preserved if you choose eitherRead Onlymode orRunBatchmode . In all cases, if you subsequently export the problem, allsupported features will be lost. The exported file will not include any ofthe unsupported features. Later import of the exported file will revealthat the unsupported features are missing. It is always prudent to makecopies of your original files and to work only on copies of the originalfiles.


PRO/II Main Window Components

Component Description

Control-menu Box Displays a menu with commands for sizing, moving andclosing the active window.

Title Bar Identifies the application and the name of the open file; can beused to move the entire window.

Minimize Button Reduces the application window to an icon.

Maximize/RestoreButton

Enlarges a window to full-screen or restores it to its defaultsize.

Menu Bar Identifies the menus available in PRO/II: File, Edit, Input,Output, Tools, Draw, View, Options, Window and Help.

Toolbar Provides pushbutton access to various Edit, Input, Tools, View,Window, and Help options

PFD Main Window Provides a workspace for placing units, making streamconnections, drawing objects, and adding text.

Horizontal Scroll Bar Functions as a sliding scale for moving the flowsheet right orleft in the PRO/II main window.

Vertical Scroll Bar Functions as a sliding scale for moving the flowsheet up ordown in the PRO/II main window.

Status Bar Displays help, information and error messages for the activefeature or object.

Border Handles Changes window height, width, or size when the correspond-ing border handle is dragged to a new position.


Manipulating the PRO/II WindowThe PRO/II window offers many features that enable you to customizeits appearance relative to the full screen and other applications.Detailed instructions on the use of the Windows graphical userinterface may be found in numerous reference manuals available at anylarger bookstore.

Changing Window SizeThe Windows interface provides tools for resizing each window. Sometools automatically change a window to a particular size and orienta-tion, others enable you to control the magnification.

Using Minimize/Maximize ButtonsThe minimize and maximize buttons automatically adjust the size of awindow.

Using Border HandlesYou can use the window border to change the size of the main window. Theborder works like a handle that you can grab with the cursor and drag to anew position.

Using the Control MenuYou can also use theControl menu toRestore, Move, Size, Minimize, orMaximizea window. Open the Control menu by clicking on the PRO/IIicon at the far left of the title bar or by pressing the <Alt+Space>.

Changing Window PositionYou can change the position of the main window (or any pop-upwindow) by dragging the title bar.


Working with On-Screen Color Coding CuesPRO/II provides the standard visual cue (grayed out text and icons) formenu items and toolbar buttons that are currently unavailable. Inaddition, PRO/II uses colored borders liberally to indicate the currentstatus of the simulation. You may customize the color coding byaccessing theSet Colorswindow by selectingOptions/Colors…fromthe menu bar.

PRO/II On-Screen Color Codes

Color Significance

Red Required data. Actions or data required of the user.

Green Optional, or default data.

Blue Data supplied by user.

Yellow Questionable data. A warning that the value suppliedby user is outside the normal range.

Gray Data field not available to user.

Black Data entry not required.

Using the MenusThe names of the PRO/II main menus appear on the menu bar. Usethese menus to access most PRO/II operations.



Figure 1-4: Edit MenuFigure 1-3: File Menu

Figure 1-5: Input Menu

Figure 1-7: Tools Menu

Figure 1-6: Output Menu


Figure 1-8: Draw Menu Figure 1-9: View Menu

Figure 1-11: Window Menu

Figure 1-12: Help Menu

Figure 1-10: Options Menu

Using the Floating PalettesThere are two floating palettes. The first contains the unit operationsand streams needed to construct a flowsheet. The second containscontrols used to run the simulation. These palettes may be displayed orhidden by selectingView/Palettesfrom the menu bar.

Menu Item Description

View/Palettes/PFD Checking this option displays the PFD palettecontaining unit operations and streams (alsoknown as the Streams/Unit palette).

View/Palettes/Run Allows running the simulation and viewingresults.

Using the Toolbar ButtonsThe main toolbar can be displayed in standard (full) or compact format.When displayed in standard format (View/Toolbar/Standardfrom themenu bar), seven groups of buttons are visible. Toolbar buttonsduplicate options available from the menus on the menu bar.

● Multiple View and PFD Palette buttons

● Data Entry Window buttons

● Go To buttons

● VLE Tool buttons

● Run/Results buttons

● Delete and View buttons

● Help button

Using the Multiple View and PFD Palette ButtonsThese buttons enable you to open multiple views of a single flowsheetand hide or display the floating PFD palette.

Button Menu Item Description

View/New View Opens another viewport window of asingle simulation problem.

View/Palette/PFD Displays or hides the floating PFD palette.


Using the Data Entry Window ButtonsEachData Entry Windowbutton provides quick access to the main dataentry window for the selected section of input.


Input/Problem Description Describes the current simulation andrelates it to a specific project.

Input/Units of Measure Sets units of measure specific to thissimulation. Each new simulationextracts defaults from the default Unitof Measure Set.

Input/ComponentSelection

Specifies the components andpseudocomponents for the currentsimulation.

Input/ComponentProperties

Supplies component properties.

Input/ThermodynamicData

Selects thermodynamic methods forthe current simulation.

Input/AssayCharacterization

Modifies TBP cutpoints and charac-terization options for generating pseu-docomponents from Assay streams.

Input/Reaction Data Defines reactions and provides heat ofreaction, equilibrium, or kinetic datafor reaction sets.

Input/Procedure Data Use this window to create or deleteProcedure blocks in order to calculatekinetic reaction rates.

Input/Casestudy Data Allows user to perform studies on abase case solution by altering parame-ters and re-running.

Input/CalculationSequence

Specifies a user-defined calculationsequence.

Input/RecycleConvergence

Specifies user-defined recycle conver-gence and acceleration options.


Using Go To ButtonsTheGo Tobuttons enable you to jump to a selected unit or stream. PRO/IIrepositions the flowsheet to place the selected unit or stream at the centerof the main window. TheStream ListandUnit List (Go To) windowsalso allow direct data entry and review of output results for the selectedstream or unit.


View/Pan View Allows quick panning through the entireflowsheet.

View/Unit List Displays a list of units in the currentflowsheet. By selecting a name, youcan jump directly to that unit.

View/Stream List Displays a list of streams in the currentflowsheet. By selecting a name, you canjump directly to that stream.

Using VLE Tools ButtonsTheVLE Toolsbuttons enable you to perform simulation functions,e.g., flash a stream highlighted on the PFD using theFlash Hot-key.


Tools/Flash Stream Flashes the stream highlighted on thePFD. (Also called the Flash Hot-key.)

Tools/Binary VLE Generates plots and tables of K-valuesand fugacity coefficients for binary pairsof components.


Using Run/Results ButtonsTheRun/Resultsbuttons duplicate functions on theRun Simulationfloating palette. They allow you to run or stop a simulation, or permitviewing of results and generating of output reports. TheGenerateOutputbutton duplicates anOutputmenu item.


�� Runs the simulation

�� Stops the simulation.

�� Allows results for the selectedstream or unit to be viewed.

Output/GenerateReport

Generates an output report for thesimulation problem.

Using Delete and View ButtonsPRO/II provides aDeletebutton and a set ofViewbuttons on thetoolbar that facilitate editing and viewing of the flowsheet. Thesebuttons duplicate items available on theEdit andViewmenus.


Edit/Delete or<Delete>

Deletes the currently selectedobject(s) from the flowsheet.

View/Zoom/Zoom In, Zoom Out

Zooms in or out of the flowsheet.

View/Zoom/Zoom Full or <Home>

Displays the entire flowsheet in thePFD window.

View/ Zoom/Zoom Area

Displays the selection rectangle usedto select a set of units, streams orobjects on the flowsheet. The selectedarea fills the PFD.

View/Zoom/Redraw or <Shift+Home>

Clears the PFD of any extraneousobject by redrawing the flowsheet.


Using the Help ButtonTheWhat Is? HelpButton displays context-sensitive help.


What Is? Displays help for the object you pointto.

Using the PRO/II Main WindowThe PRO/II main window (PFD) is the main drawing board. On the PFD youmay place the following objects:

● Unit operations from the PFD palette

● Stream connections

● Text

● Drawings

● Stream property tables

Use the PRO/II main window to see the contents of your simulation.You can choose to view the entire flowsheet or only a portion of it. Youcontrol the view using scroll bars, pan options, the zoom bar, or arrowkeys.

Note: SeeChapter 5, Manipulating Objects,for information aboutplacing, selecting and changing the size of objects in the PFD.


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Chapter 2Simulation Basics

In the previous chapter, you learned some of the basic window features ofPRO/II. In this chapter you will learn simulation basics; that is, how to set upsimulation problems, solve them, and analyze the results.

General ApproachThis chapter provides a quick overview of the use of PRO/II for solvingengineering problems. A suggested basic approach is given, as well ashelpful explanations of the information flow in PRO/II. Sample dataentry windows are given to illustrate data entry for PRO/II. Step-by-step examples are available in thePRO/II Tutorial Guide. Online help isalso available.

You have already learned that PRO/II gives you great flexibility andmany options when supplying simulation data. For many items of data,default values are supplied. A color code informs you when data arerequired, supplied by default, out of normal ranges, or missing.

Note: You must supply data for all red-bordered fields or red linked text(including data required) before running your simulation.

Problem data may be supplied in almost any order: PRO/II warns youwhen required data are missing. However, it is still best to follow alogical path when supplying simulation data. For example, someoptions such as stream compositions are dependent upon the compo-nents selected. Some unit operations, such as the flash drum, havefeatures that are dependent on the thermodynamic data. For some otherunit operations, performance specifications based on the components inthe system are the preferred way to define the operation.

For these reasons, the following approach is recommended whenbuilding a simulation flowsheet:

Draw the FlowsheetSelect the unit operations needed for the flowsheet calculations andposition them on the PRO/II PFD main window.

PRO/II User's Guide Chapter 2 Simulation Basics2-1

Connect the Unit Operations with StreamsThe streams are the connectors for the process calculations, with infor-mation passed from one unit operation to another via the processstreams.

Define the Components in Your SystemIt is best to order the components in volatility order, starting with thelightest component. This makes it easy to analyze the separationswhich occur in unit operations such as distillation. While not anecessity, for hydrocarbon/water systems, defining water as thefirstcomponent is also a good idea. This makes it easy to see the breakbetween the aqueous and non-aqueous phases. User-defined petroleumpseudocomponents and/or polymer components for which you supplydata should be entered next. Petroleum pseudocomponents generatedby PRO/II from petroleum stream assay data will appear last in thecomponent lists of the output reports.

Select the Thermodynamic and Transport Property MethodsFor many problems, a system may be selected from theMost CommonlyUsedthermodynamic methods. Guidelines for thermodynamic methodsare provided in the PRO/II online help, and in thePRO/II ReferenceManual(both in online help and in hardcopy forms). Further assistanceis available through SIMSCI Technical Support. Selecting a properthermodynamic method is acritically importantstep in the solution of asimulation problem.

Supply Data for the Feed Streams and Recycle StreamsYou must supply thermal conditions, flowrates, and compositions forall external feed streams to the flowsheet. It is usually desirable,although not necessary, to provide estimated data for recycle streams tospeed convergence of recycle calculations.

Supply Operating Conditions for the Unit OperationsDouble-click the icon for each unit operation to access the data entrywindows. The color codes tell you what data you must supply and whatdata have default values. You may also use the online help to learn moreabout the calculation options, data entry items, etc., for each unit operation.

A quick review is also a good idea at this point. Do the thermodynamicmethods support the unit operation calculations? Are transport proper-ties required for any of the unit operations?

Chapter 2 Simulation Basics PRO/II User's Guide2-2

Run the Process SimulationPRO/II lets you know by color code when sufficient information hasbeen supplied to perform the calculations. When all of the borders onthe toolbar icons have changed from red (indicating missing data) togreen or blue, you are ready to run your simulation. At this point, youmay click theRun(right arrow) icon on the toolbar or theRun buttonon the floating Run palette to begin the flowsheet calculations.

Analyze the Simulation ResultsUse the many convenient report and plotting features of PRO/II toanalyze the simulation results. At this point, your training as anengineer should take charge. Are the results reasonable? How do theresults compare with the plant data? Can differences be reconciled?Are better data for the feedstocks needed? Are the models adequate forthe intended purposes?

Now that we have presented an overall plan for simulating a flowsheet,let’s look at some of the individual steps in more detail.

Building the FlowsheetUnit OperationsUse the floating PFD palette to begin building the flowsheet. The iconsand names for the unit operations appear as buttons on the PFD palette.To add a unit operation to the flowsheet, click the unit icon on the PFDpalette and click-drop it at the desired location on the flowsheet.

StreamsClick the Streams button on the top of the floating PFD palette. ThePFD is now in stream mode and a small “S” is attached to the cursor.You will notice that all possible exit ports for each unit operation arenow marked. Required outlet ports are colored in red; green is used tomark optional ports. PRO/II adds each stream to the flowsheet in anorthogonal manner, following a rectangular grid pattern.

As soon as a valid flowsheet has been built, i.e., all required inlet, outlet,and connector streams have been added for all the process units, the redborder around theStreams button on the PFD palette changes to blue.


Required DataNow that the flowsheet has been built, it’s time to supply the requireddata for the calculations: the components and thermodynamic methodsmust be defined, inlet feed streams and, optionally, recycle streamsmust be supplied, and the operating conditions for the unit operationsmust be specified.

ComponentsTo define the components, selectInput/Component Selectionfrom themenu bar or click on the benzene ring toolbar icon to open theComponent Selectionmain window. Note that this icon has a redborder, indicating that components have not yet been defined.

Library components for which the library access names are known maybe directly typed into this window, where they are transferred to theList of Selected Componentsfor the problem. A convenient searchprocedure isalso provided which may be used by clicking theSelect

from Lists... button. Petroleum (PETRO) components are defined in thePetroleum Componentswindow which is reached by clicking the

Petroleum... button. Non-library components can be defined in theUser-definedwindow which is reached by clicking theUser-defined...button.

Note that petroleum pseudocomponents defined by PRO/II frompetroleum stream assay data do not appear in theComponent Selectionmain window.

Thermodynamic MethodsThermodynamic methods are defined in theThermodynamic Datamainwindow which is reached by selectingInput/Thermodynamic Datafromthe menu bar or by clicking on the phase diagram icon. Note that this iconis initially outlined in red, indicating that thermodynamic methods must bedefined for the problem.

For most problems, a predefined set of thermodynamic methods forcalculating K-values, enthalpies, entropies, and densities may be used.PRO/II offers numerousCategoriesof method sets. After a category hasbeen selected, you may select a method set within that category as aDefined Systemfor the problem and modify it by clicking theModify...button to access theThermodynamic System-Modificationwindow. Notethat transport property calculations are not included in the predefined methodsets. If they are required for the problem, you must add them to the prede-fined thermodynamic method set in this window.


Stream InformationThe identifiers for feed streams requiring input data are marked withred borders indicating that information is missing. Stream information issupplied in theStream Datamain data entry window which is reached bydouble-clicking a stream identifier. The predefined stream identifier mayalso be changed in this window.

Three types of information must be supplied in this window: the thermalcondition of the stream, the flowrate for the stream, and the composition ofthe stream. For petroleum assay streams, the assay data are providedinstead of the composition data, and PRO/II defines the stream compositionfor you in terms of petroleum pseudocomponents.

Although optional, it is good practice to provide reasonable estimates forrecycle tear streams in order to accelerate convergence of problem recyclecalculations.

Unit OperationsUnit operation identifiers for which data entries are needed are markedwith red borders. To enter information for a unit operation, double-click its icon to retrieve theUnit data entry window. Various inputoptions and numeric values are supplied via this parent window and itschild windows. Required information is always bordered in red; dataentry fields for items with supplied defaults are always bordered ingreen. After you have supplied information in a data entry field, theborder color changes to blue. Information you have supplied which liesoutside the normal range for the field is marked with a yellow border.

You may also change the default unit identifier in this window andfurnish a longer, more descriptive name for the unit operation. Noticethat when you return to the flowsheet, the unit identifier on the PFD hasa black instead of red border, signifying that all data entry requirementsare satisfied. If the border is still red, you must return to the data entrywindow for the unit operation and supply the missing data.

Miscellaneous DataAll data entries in this category are optional. PRO/II provides defaultentries. In some cases global values may be used to supply thedefaults, as explained inChapter 4, Building a Flowsheet.

Miscellaneous data categories include problem descriptive information,the calculation sequence, recycle convergence options, flowsheet toler-ances, and the scaling of product streams.


Problem descriptive information is optional; however, it can be benefi-cial to document a simulation model for future users. This informationincludes a project name, problem name, user name, date, site, andproblem description. This information is supplied in theProblemDescriptive Informationwindow, which is accessed by clicking thetoolbar icon with the printed page icon or by selectingInput/ProblemDescriptionfrom the menu bar.

For most problems, the calculation order determined by PRO/II is satis-factory. To supply your own sequence, click the toolbar icon with thetwo connected flowsheet blocks or select theInput/CalculationSequencefrom the menu bar.

Definitions of recycle loops are automatic. To define your own loops, orto use acceleration techniques, click the toolbar icon with the flowsheetloop icon to enter theProblem Recycle Convergence and AccelerationOptionswindow or select theInput/Recycle Convergencefrom themenu bar.

Flowsheet tolerances are used for convergence of unit operation specifi-cations and may be changed in theDefault Unit Specification Toler-anceswindow, which is reached by choosingInput/FlowsheetTolerancesfrom the menu bar.

All flowsheet results may be scaled so that a desired flow is obtainedfor a product stream. To use the scaling feature, select theOutput/Report Format/Miscellaneous Data. Click the Product Stream

Scaling... button on theMiscellaneous Report Optionswindow toaccess theScale Stream Flowratewindow.

Default DataTo simplify data input, PRO/II supplies default options and valueswherever practical. Default values supplied by PRO/II are printed in blackin a data entry field with a green border, or in the case of linked text, ingreen. For example, the default number of iterations for a column unitoperation using the IO method is supplied as 15. Entries which you mustalwayssupply are indicated with a color red because they have nodefault values.

While you do not need to replace a default entry to satisfy the inputrequirement for PRO/II, default data should be inspected carefully toascertain that they meet your requirements. When you replace a defaultvalue, the border color for the data entry field changes to blue, indi-cating that you have supplied this value. For linked-text strings, the


color of the linked text is also changed to blue, indicating that you havereplaced the default value.

Optional DataOptional data, which are displayed in black, are data or options notspecifically necessary for the unit operations to proceed. For example,theDescriptionentry is optional for all unit operations. A reboiler isoptional for theColumnunit operation, since the calculation require-ments may also be satisfied by a vapor feed to the bottom tray of thecolumn.

Data options which do not apply to a particular combination of inputdata appear in the color gray, and are not available for data entry. Forexample, when the kettle reboiler option is selected for a columnreboiler, the data entry fields for a thermosiphon reboiler are coloredgray.


Chapter 3Managing PFD Files

This chapter describes how to open, save, close, delete and copy simulationfiles. In addition, this chapter outlines how to import a PRO/II keywordinput file or export a flowsheet.

Opening a New SimulationWhen you start PRO/II, the program does not automatically bring up anew, untitled simulation.

Note: If you want PRO/II always to open with a new simulation, selectOptions/New File on Startup from the menu bar.

To open a new simulation:➤ ChooseFile/New. . . from the menu bar. PRO/II clears the main

window for a new simulation and opens the initial viewportwindow,View 1.

Figure 3-1: PRO/II Main Window

PRO/II User's Guide Chapter 3 Managing PFD Files3-1

Opening an Existing SimulationYou can open any previously saved simulation for modification, viewing orprinting. PRO/II opens the flowsheet file and its supporting PRO/IIdatabase files.

To open an existing simulation:➤ ChooseFile/Open... from the menu bar. PRO/II displays theOpen

Simulationwindow.

Figure 3-2: Open Simulation Window

➤ Type or select the name of the simulation file.

➤ Choose OK or press <Enter>. PRO/II displays the simulation inthe PFD main window.

Note: PRO/II 5.x provides a file converter for import of PRO/II 4.x fileswith the exception of Add-On Module files.

Saving the Current SimulationBefore you close a simulation, you should save it. You may also want tosave the simulation periodically while creating it.

To save the current simulation:➤ ChooseFile/Savefrom the menu bar. If youhave not previously

saved this simulation, PRO/II displays theSave Aswindow.

Note: PRO/II 5.x automatically compresses the three PRO/II databasefiles (*.pr1, *.pr2, *.pr3) and the simulation flow diagram file (*.sfd)into a single *.prz file. Beside reducing the size of stored files, PRO/II

Chapter 3 Managing PFD Files PRO/II User's Guide3-2

file compression assures that a complete set of files for each simulationhas been saved.

Figure 3-3: Save As Dialog

➤ Type a name for this simulation.

➤ Choose OK or press <Enter>.

Note: The PRO/II Autosave functionality automatically creates a backupfile at user-specified intervals from which recovery can be made. If youclose or exit the simulation without saving, this backup file is deleted.Select Options/Simulation Defaults/Autosave… from the menu bar toaccess the Autosave Options window.

Saving a Simulation to Another NameYou can save a simulation to another name. Changes you made to thesimulation since the last save are saved as part of the simulation underits new name.

Note: If you’ve made changes to a simulation and don’t want to alterthe original simulation, but do want to keep the changes, use Save As.

To save the current simulation to another file name:➤ ChooseFile/Save As... from the menu bar.

PRO/II prompts you for a new file name.

➤ Type a name for the simulation.


PRO/II appends a .PRZ extension to the filename.


Closing a SimulationYou should save a simulation before closing it, although PRO/II willprompt you to save changes for an existing simulation.

To close a simulation:➤ ChooseFile/Closefrom the menu bar.

If you close a simulation without first saving the simulation files, youlose any changes you made to the simulation since the last save.

Deleting a SimulationYou can delete any simulation except the current (active) simulation atany time.

To delete a simulation file:➤ ChooseFile/Delete... from the menu bar. PRO/II displays a list of

existing PRO/II simulation files.

Figure 3-4: List of Files

➤ Type or select the name of the file you want to delete. (You maynot delete the current simulation.)

➤ Choose OK or press <Enter>. PRO/II deletes all files associatedwith this simulation.


Copying a SimulationYou can copy all files associated with a simulation (one flowsheet and threedatabase files) to a target simulation you name. You can copy to new orexisting file. If you copy to an existing file, PRO/II verifies if you want tooverwrite the existing file.

To copy a simulation file:➤ ChooseFile/Copy... from the menu bar.

Figure 3-5: Copying Files

➤ Select the name of the file you want to copy from the file selector.(You may not copy the current simulation.)

➤ Enter a name for the copy (target).

➤ Chose OK or press <Enter>.

PRO/II copies all files associated with the simulation.

Note: There may be as many as 17 separate files associated with asingle simulation problem. These are described in Table 3-1.


Table 3-1: PRO/II Simulation Files

File Extension Description

*.pr1, *.pr2, *.pr3 PRO/II database files

*.sfd Graphics file

*.prz Compressed files containing *.pr1, *.pr2, *.pr3 and*.sfd files.

*.out Main output file

*.ot1 Component, calculation sequence, recycleloops/streams output data

*.ot3 Equipment/streams output data

*.sr1 Input source listing

*.ix3 Output index

*.hs2 Calculation history

*.inp Keyword input file

*.plt Plots saved in the plot display window

*.txt Stream property tableor plot (saved in ASCII format)

*.csv Stream property tableor plot (saved in tabular format)

*.clp Graphics saved in Clipboard format

*.prc Temporary procedure file created and removed byPRO/II. Only remains if there is an abnormal termina-tion.


Importing a PRO/II Keyword Input FileYou can import an existing PRO/II keyword input file into the PRO/IIgraphical user interface and then execute the simulation problem just asif you had entered the problem using the PFD graphical main window.PRO/II automatically converts the specified keyword input file into aflowsheet and displays it in the PFD window.

To import a PRO/II keyword input file:➤ ChoosingFile/Import from the menu bar.

PRO/II displays a list of existing keyword input files.

Figure 3-6: List of Files

➤ Type or select the name of the keyword file that you want to im-port.


PRO/II converts the selected keyword input file into a flowsheet anddisplays it in the PFD main window automatically.

Keyword Features without PRO/II GUI supportThe RESTART feature is not supported by the graphical user interfacein this version of PRO/II. You will not be allowed to import keywordfiles that contain this feature.

If a RESTART keyword is detected upon import, you will be remindedthat only the “Run Batch” feature of PRO/II may be used with thesekeyword input files. SeeChapter 10, Running and Viewing aFlowsheet, for information on running keyword files in “Batch” mode.


Keyword Features that can be imported into PRO/II in �Run-Only� ModeCertain keyword features are not fully supported by the graphical userinterface of PRO/II. However, if one of these unsupported features isdetected, you will be allowed to import the keyword file, however theGUI interface will operate in the “Run-Only” mode. Such unsupportedkeywords include:

● BVLE Data

● Stream Report Writer

● Hydrate Unit Operation

● HEXTRAN Property Data Generator.

If you attempt to import a keyword input file that contains PRO/IIprogram features not supported by the graphical user interface, theunsupported features will be automatically listed in a status window.You have the option to save or delete the unsupported features. If youchoose to save the unsupported features, PRO/II will run the file inRun-Only Mode.

In �Run-Only� mode, you can:● Review and modify the PFD graphic image. You may move

unit operation icons and streams around to improve the appear-ance of your PFD.

● Add drawing elements to the PFD.

● Add stream property tables to the PFD.

● Have access to all the capabilities on the Run palette (performall interactive execution functions available on the Run palettefor both supported/unsupported units, review the calculatedresults on the PFD for all streams and supported/unsupportedunits, generate output reports for all features, generate plots forsupported features only).

● Export the flowsheet and stream property table information toother Windows applications.

● Edit the keyword file, reimport, and rerun (without leavingPRO/II).

● Use the stream flash icon.

In �Run-Only� mode, you cannot:● View simulation data with the data entry windows. This

includes Component and Thermodynamic data. Double-clicking on a unit operation or stream will cause a shortwarning message to be displayed.


● Perform any input mode functions, including changing thecalculation sequence. All buttons and menu options that accesssimulation data will be disabled.

● Perform any of the following functions: adding/deleting units,adding/deleting streams, and reconnecting streams.

● Export the PRO/II keyword input file.

If you attempt to import a keyword containing an unsupported feature,the following message window will be displayed:

Figure 3-7: Unsupported Features Warning Window

If you click Yes , a message window similar to the following will bedisplayed:

Figure 3-8: Flowsheet Status Window for Unsupported Features

Once you close the message window, the interface will be placed to the“Run-Only” mode as illustrated in Figure 3-9.


Figure 3-9: PRO/II in “Run-only” Mode

➤ Click the Run button on the Run palette.

Once the flowsheet has been solved, you may double-click a unit orstream to view the results.

Exporting Simulation Data to a PRO/II Keyword FileYou can export an existing PRO/II simulation flowsheet to a keywordinput file as follows:

➤ ChooseFile/Export from the menu bar. PRO/II displays theExportwindow which lists the data export options.


Figure 3-10: Available Data Export Options

➤ Choose theSimulation Data to Keyword Fileoption.

➤ Click the OK button.

PRO/II converts the current simulation flowsheet data into a PRO/IIkeyword input file in ASCII format. The name of the keyword file willbe YYY.INP, where YYY.PR1 is the name of the simulation flowsheetPRO/II database file.

Using the Spreadsheet ToolsTheTools/Spreadsheetmenu item can be used to start a spreadsheettool. The list of currently installed tools will appear in a side menu.

Spreadsheet tools are Excel template files and macros that can readinformation in the PRO/II simulation database to generate reports orperform additional on-the-spot calculations. They can also update datain the simulation database itself using data from an Excel spreadsheet.

Note: You must have Microsoft Excel installed on your system to usethese tools.

PRO/II comes preinstalled with some default spreadsheet tools. Theycan be used to create tables of stream properties or componentflowrates or generate a distillation report.


Exporting the Flowsheet Drawing to the ClipboardYou can export part or all of the flowsheet drawing to the Clipboard.You can then paste this drawing into other Windows applications.

To export the entire flowsheet drawing to the Clipboard:➤ ChooseFile/Export from the menu bar. PRO/II displays theExport

window (Figure 3-10).

➤ Choose theFlowsheet Drawingoption.


To export one page of the flowsheet to the Clipboard:➤ Select the page to export by clicking on its edge on the PFD.

➤ ChooseFile/Export from the menu bar. PRO/II displays theExportwindow (Figure 3-10).

➤ Choose theSelected Page of Flowsheet Drawingoption.


Exporting Stream Property Table DataYou can export the information in a stream property table to an ASCIIfile for import into spreadsheet and word processing applications.

To export data from a stream property table:➤ Select the stream property table to export on the PFD.


➤ Choose theStream Property Tableoption.

➤ Click the OK button. TheExport File Filter window will bedisplayed (see Figure 3-11).

➤ Enter a name for theOutput File.

➤ Select the desired file format (tab-delimited or comma-delimited)from theSave File as Typedrop-down list box.



Figure 3-11: Export File Filter Window

PRO/II then generates the ASCII file. To import this file into yourspreadsheet or word processing program, follow the instructionsincluded with that application.

Copying Stream Property Table Data to the ClipboardYou can copy the information in a stream property table to theclipboard. This table can then be pasted into any other Windowsapplication.

To copy a stream property table to the Clipboard:➤ Select the stream property table on the PFD.

➤ ChooseEdit/Copyfrom the menu bar.

Exporting the PFD to an AutoCAD or PostScript FileYou can export your flowsheet drawing as an AutoCAD .DXF orEncapsulated PostScript (.EPS) file:


➤ Choose theFlowsheet to AutoCAD .DXFor Flowsheet to Post-Scriptoption.

➤ Click the OK button. TheSave Aswindow appears.

➤ Enter a name for the .DXF or .EPS file.


Chapter 4Building a Flowsheet

This chapter describes how to construct a flowsheet. It begins bydescribing the various defaults that may apply to your simulation on aglobal, simulation, or unit level. This chapter also includes instructionsfor placing unit operations, connecting units, and drawing objects thatenhance the presentation of your flowsheet without affectingcalculations.

Setting Simulation PreferencesPRO/II enables you to set global defaults for problem descriptionsinformation, units of measure and thermodynamic systems. Theseglobal defaults apply to all simulations unless you specifically overridethem either for a particular simulation or unit operation.

On a simulation level, you can set problem-specific input and outputunits of measure defaults. Simulation level settings override globaldefaults. In addition, you can change units of measure settings for aspecific unit. This setting overrides both simulation and global defaults.

Setting Problem Description Global DefaultsTheProblem Description Information(Project Identifier, Problem Iden-tifier, User Name, Date, Site) appears on each page of a results printoutas a heading and theProblem Descriptionitself appears on the firstpage. All simulations use the global problem descriptive informationunless you override the defaults for a particular simulation.

To set problem description global defaults:➤ ChooseOptions/Simulation Defaultsfrom the menu bar.

➤ ChooseProblem Description.TheGlobal Default for ProblemDescriptive Informationwindow appears.

PRO/II User's Guide Chapter 4 Building a Flowsheet4-1

Figure 4-1: Global Default for Problem Descriptive Information

➤ Complete the window.

➤ Click OK .

Overriding the Global Default Problem DescriptionBefore laying down your flowsheet, you may want to update theproblem description for the current simulation. PRO/II uses the globaldefaults for all simulations, unless you specifically override the data fora particular simulation.

To override the global default problem definition:➤ Click on the Problem Description icon or chooseInput/Problem

Descriptionfrom the menu bar. TheProblem Descriptive Informa-tion window appears.

You can enter up to ten problem description lines (80 characters each),that will appear on the first page of a results printout.

Chapter 4 Building a Flowsheet PRO/II User's Guide4-2

Setting Units of Measure Global DefaultsBy default, PRO/II uses the English units of measure set for all input dataand for output reports. These defaults apply to all new simulations. You canoverride the default set for either input data or output reports (or both) forall new simulations. PRO/II maintains a library of units of measure setsthat you can select from and add to.

To set the unit of measure global defaults:➤ ChooseSimulation Defaultsfrom theOptionsmenu.

➤ ChooseUnits of Measure.TheDefault Sets of Units of Measurewindow appears.

Figure 4-2: Global Units of Measure Sets

➤ Select the desired default units of measure set for entering simula-tion data. The default choice is ENGLISH-SET1, i.e., the data inputwill be in English units.

➤ Select the desired default units of measure set for generating thefirst output report. The default choice isSame as Input, i.e., the firstoutput report will be printed in the default English units.

If any choice other than the default is selected, the second output reportwill no longer be available, and the list-box for selecting the alternateunits of measure set for the second output report will be disabled.

Select the desired default units of measure set for generating the secondoutput report. The default choice isNone, i.e., no second output reportin alternate units will be generated.


Setting Units of Measure Simulation DefaultsPRO/II sets English units as the default for units of measure. You canoverride this default, setting the global units of measure for all newsimulations. In addition, you can override the default units of measurefor a particular simulation problem.

To set the units of measure for the current simulation:➤ Click on the Input Units of Measure icon or chooseInput/Units of

Measurefrom the menu bar. TheDefault Units of Measure forProblem Data Inputwindow appears.

Figure 4-3: Default Units of Measure for Problem Data Input Window

➤ Select different dimensional units for data input for each individualcategory or chooseInitialize from UOM Library... to automaticallyfill in the defaults from another set.

➤ Click on the Standard Vapor Conditions... button to enter theProblem Standard Vapor Conditionwindow. The default tempera-ture and pressure bases are shown in data entry fields and may bereplacedor the standard vapor volume per mole may be replaced,but not both. PRO/II default values are:

Temperature Pressure Vapor Volume

English 60°F 14.696 psia 379.48 ft3/lbmol

Metric 0°C 1.0332 kg/cm2 22.414 m3/kgmol

SI 273.15 K 101.32 kpa 22.414 m3/kgmol


The current atmospheric pressure (Pressure Gauge Basis) is shown in adata entry field and may be replaced with another value as desired. ThePRO/II default value is 14.696 psia or the metric equivalent.

➤ Click on the TVP and RVP Conditions... button to select theProb-lem TVP and RVP Conditionswindow. The temperature for true va-por pressure specifications may be replaced in this window. ThePRO/II default for TVP calculations is 100°F. The calculationmethod for Reid vapor pressure may be selected in a drop-down listbox on this window. Choices are:

■ API Naphtha (the default)

■ API Crude

■ ASTM D323-73

■ ASTM D323-82

■ ASTM D4593-91

■ ASTM D5191-91

➤ Click OK .

Units of Measure LibraryA library of dimensional unit sets which may be used for data entry orreport writing is maintained with this feature. To add a new set to thelibrary or to edit an existing set:

➤ SelectOptions/Units of Measure Listfrom the menu bar.

TheUnits of Measure Librarywindow appears and may be used to create,copy, edit, rename, and delete dimensional unit sets. TheUnits of MeasureSet NameandDescriptionlist box contains the names of the dimensionalunit sets currently in the library. The program provides three initial dimen-sional unit sets: English (the default), Metric, and SI.

To create a new set:➤ Click the Create... button on theUnits of Measure Library

window to get theCreate Units of Measure Setwindow.


Figure 4-4: Units of Measure Library

➤ Supply a name for the new set in the data entry field provided, andselect the basis for the set with the appropriate radio button:English, Metric, or SI.

Figure 4-5: Create Units of Measure Set Window

➤ Click on OK to continue.

The units for the standard dimensional unit sets in PRO/II are assignedto the new set and the edit feature may now be used to customize theset.


Note: An alternate way to create a new set is to highlight an existingset in the Units of Measure Set Name and Description list box and clickthe Copy button on the Units of Measure Library window. The namefor the new set is then entered in the Copy Units of Measure Set win-dow. The Edit feature may now be used to customize the set.

To delete, rename or edit a set:➤ Select the set in theUnits of Measure Set Name and Description

list box.

➤ Click the Delete , Rename , or Edit button on theUnits ofMeasure Librarywindow.

Editing the Dimensional Unit Sets for Output ReportsA dimensional unit set for output reports may be edited in two places inPRO/II:

1. Library sets are edited with theEdit... feature in theUnits ofMeasure Librarywindow.

2. The set being used for the current problem is edited in theDefaultUnits of Measureof the Problem Output Report which is accessiblefrom the PFD main window by:

■ Selecting theOutputmenu on the menu bar.

■ Selecting theReport Formatfrom theOutputmenu.

■ SelectingUnits of Measurefrom theReport Formatmenu.Editing of the dimensional items is identical for these twowindows.

The dimensional unit set for the output report is initialized from theglobal set, as previously explained. However a different set may bechosen from the units of measure library while in theDefault Units ofMeasure for Problem Output Reportwindow. To use a different dimen-sional unit set:

➤ Click the Initialize from UOM Library... button. TheInitialize Unitsof Measure from UOM Librarywindow appears.

➤ Select the desired set from the drop-down list box.

➤ Click the OK button to continue. This set now becomes the outputreport set. The newly selected output report set may be edited inthis window as desired. The edited set is saved with the problem.


ThePrint Option for output reports may also be selected using theOutput Report(s) to be Printeddrop-down list box where options are:

One Output Report in Input Units (the default): When this option isselected, an output report based on the units of measure used for theproblem data input will be generated. The currently specified inputunits of measure will be displayed for informational purposes, but theycannot be changed. With this option, the output units of measure canonly be changed by selecting theUnits of Measureoption from theInput menu.

One Output Report in Output Units: When this option isselected, anoutput report based on the output units of measure specified will begenerated. The currently specified output units of measure will bedisplayed, and they can be changed if desired.

Two Output Reports, one in Input Units, one in Output Units:When this option is selected, two output reports will be generated, oneeach based on the input and specified output units of measure will begenerated. The currently specified output units of measure will bedisplayed, and they can be changed if desired.

For the second and third cases discussed above, the displayed outputunits of measure set can be copied from the specified input units, orinitialized from one of the units of measure sets stored in the units ofmeasure library.

To copy the input units of measure set to be used for the outputreport, or to reset the explicitly specified output units to thepreviously specified input units:➤ Click the Copy from Input UOM button on theDefault Units of

Measure for Problem Output Reportwindow.

➤ Click OK to continue.

To initialize the output units of measure set from a units of measureset stored in the units of measure library:➤ Click the Initialize from UOM Library... button on theDefault Units

of Measure for Problem Output Reportwindow.

➤ Click OK to continue.

If the results of a previously executed simulation must be printed in adifferent set of dimensional units, it is only necessary to select therequired units through this feature and generate a new report. The entiresimulation need not be executed from the start just to obtain the outputresults in a different set of dimensional units.


Setting Thermodynamic System Global DefaultsTo set the thermodynamic system global defaults:➤ ChooseSimulation Defaultsfrom theOptionsmenu.

➤ ChooseThermodynamic System.TheGlobal DefaultThermodynamic Systemwindow appears.

Figure 4-6: Global Default Thermodynamic System Window

➤ Complete the window.

➤ Click OK .

Note: This global default will not become effective until the next timeFile/New is selected.


Setting General Drawing DefaultsPRO/II allows you to change the appearance of your workplace throughtheGeneral Drawing Defaultswindow. You can set the snap and movetolerances, zoom and pan increments, the PFD palette icon, icon fill,unit snapping, and delete confirmation. The defaults, shown below inFigure 4-7, are appropriate for most scenarios and you may never needto make changes in this window.

To make changes to the general drawing defaults:➤ ChooseOptions/Drawing Defaults/General...from the menu bar.

Figure 4-7: General Drawing Defaults Window

Changing Delete ConfirmationBy default, PRO/II prompts you to confirm each delete operation. You maywant to change this default setting.

To turn delete confirmation off:➤ Within theGeneral Drawing Defaultswindow, uncheckConfirm

Deletesto turn the option off.


Setting Global Flowsheet TolerancesYou use this option to identify the acceptable margins of error andcriteria for satisfying certain numerical methods. Some flowsheet toler-ances, such as the tolerance for flash calculations, are internal and arenot user-definable. The default flowsheet tolerances are satisfactory formost problems.

To set the tolerance for this flowsheet:➤ ChooseInput/Flowsheet Toleranceson the menu bar.

Figure 4-8: Default Unit Specification Tolerances


Placing a Unit on the FlowsheetThe PRO/II main window is your drawing board. PRO/II supplies afloating PFD palette and drawing objects that help you draw yourproblem quickly.

The PFD palette shows icons for each unit operation that you can selectto place on the flowsheet. The PFD palette appears automatically whenyou open a new or existing file, or when you import a keyword file.

To close or open the PFD palette:➤ Click on the Palette on/off icon, or select theViewmenu on the

main PRO/II window. Check thePalettes/PFDoption on or off.

Selecting a Unit from the PFD PaletteTo select a unit icon for placement and place it on your flowsheet:➤ Choose the icon from the PFD palette (see Chapter 9 for unit

descriptions).

➤ Position the cursor where you want the unit icon to appear andclick the left mouse button.

Figure 4-9: Placing a Unit


SnappingWhen connecting two units with a stream PRO/II will adjust or “snap”the unit icon positions to straighten the connecting stream. By default,units you add to or move in the PFD main window snap to an invisiblegrid. You can turn grid snapping off.

To turn grid snapping off:➤ ChooseDrawing Defaultsfrom theOptionsmenu.

➤ SelectGeneral.

➤ SelectUnit Snapping. Theü disappears from theUnit Snappingcheck box.

Placing Multiple Unit IconsYou can place a series of unit icons in succession.

To place more than one unit at a time:➤ Select the desired unit from the floating PFD palette.

➤ Press <Shift>, and while holding down <Shift>, click on the PFDmain window to place the icon.

➤ While still holding down <Shift> click on the PFD main window toplace the second icon.

➤ Repeat for each additional placement of this icon.

Canceling Unit PlacementTo cancel unit placement:➤ Click the right mouse button.

Deleting a UnitTo delete a unit already on the flowsheet:➤ Click on the unit icon you want to delete.

➤ Click on the delete icon on the toolbar, or press <Delete>, or clickthe right mouse button and selectDelete.


Relabeling a UnitPRO/II automatically labels each unit icon you place on the PFD mainwindow. You can change the label for a unit by modifying the label onits data entry window. By default, the label consists of a character anda one-digit auto incrementing number.

To relabel a specific unit:➤ Double-click on the unit you want to rename. The data entry

window for that unit appears.

Figure 4-10: Unit Data Entry Window

➤ Type over the default name forUnit.

➤ Choose OK .


Drawing StreamsStreams mode is used to lay out the connections between units and feedand product streams. The product ports for each unit automaticallyappear when you depress the Streams button. Required product portsare red, while optional product ports are green. For some unit opera-tions, an entire side of the unit will be red or green denoting multipleconnections to that port.

To use Streams mode or display ports:➤ Select the Streams button on the PFD palette.

Figure 4-11: Streams Button Down

The cursor changes to an arrow with a small S to indicate Streams mode.PRO/II displays the product ports for each unit in the layout. Todisplay feed ports, depress the left mouse button while the Streamsbutton is depressed.

Drawing Feed StreamsTo draw a feed stream:➤ Click on an unoccupied area of the PFD main window.

➤ Click the mouse on the feed port you want the incoming streamconnected to.


Drawing Product StreamsTo draw a product stream:➤ Click the left mouse button on a product port.

➤ Click the left mouse button again where you want the stream toend.

Drawing a ConnectionTo connect units:➤ Click the left mouse button on a port to anchor or start a stream.

The ports and port colors for some unit operations change depending onthe port you selected.

➤ Click the mouse again at the other unit you want to connect.PRO/II draws an orthogonal line to connect the ports.

Figure 4-12: Feed, Product, and Connection Streams Layout

Canceling a ConnectionTo cancel a stream connection:

➤ Click the right mouse button or press <Esc>.

Changing a ConnectionTo change a connection:➤ Click the end (port) of the stream and hold down the mouse button.

➤ Drag the end of the stream to a new port.

➤ Release the mouse button.


Connecting Streams When One Unit is Not VisibleIn order to complete a stream connection, the ending unit for the streamsegment must be visible in the PFD main window. You may openanother viewport window of the same simulation and move to the endport you wish to view. Alternately, you can also use the scroll bars, thePan View window, Search for Unit, or Search for Stream tool to displaythe end port.

Labeling a StreamPRO/II automatically labels each stream you place on the PFD mainwindow. By default, the label consists of an S followed by an autoincrementing number. You can change the label for a stream bychanging the label on its data entry window.

To relabel a stream:➤ Double-click on the stream you want to relabel. TheStream Data

window appears.

➤ Type over the default name forStream.

➤ Choose OK.

This stream will now show the new label; other streams retain theoriginal labeling scheme.

Moving StreamsYou can change the route of the stream between two connectionswhenever you wish.

To move a stream:➤ Click on the end of the stream you want to move.

Drag the stream to the new location.➤ Release the mouse button to drop the stream in place.

Re-routing StreamsAs you add new connections, PRO/II automatically performs a streamroute calculation. When you move a stream or a unit operation icon,this calculation may no longer be valid. You can recalculate an unob-structed, orthogonal path for selected streams.

To re-route a stream:➤ Select the stream(s) you want to reroute.

➤ ChooseReroutefrom theEdit menu.

PRO/II calculates the best route for these streams and automaticallyre-routes them.


Searching for a Unit or StreamPRO/II builds two lists that identify the units and the streams you haveplaced on the flowsheet. TheUnit List identifies each unit by name.TheStream Listidentifies each stream by name.

Going to a UnitTo search for a unit:➤ Click on the Go to Unit icon or selectView/Unit List. The

Search for Unitdialog box appears, showing the names of all unitscurrently placed on the flowsheet diagram.

➤ Select the unit you want to go to. The unit appears at the center ofthe PRO/II main window.

Going to a StreamTo search for a stream:➤ Click on the Go to Stream icon or selectView/Stream List.The

Search for Streamdialog box appears, showing the names of allstreams currently placed on the flow diagram.

➤ Select the stream you want to go to. The stream appears at thecenter of the PFD.

Note: These search tools are only available on the toolbar if theStandard Toolbaris active.

Changing the Flowsheet LayoutPRO/II provides a variety of layout templates that change the look ofyour process flow diagram. Each template uses a different algorithm forcalculating the position of unit operations and stream connections. Youdo not have to re-execute a simulation in order to change its layout.

To change the layout of your diagram:➤ ChooseLay Out Flowsheetfrom theViewmenu. A cascading menu

appears to the right of theViewmenu.

➤ Choose one of the following layouts:

■ Single Line

■ Multi-line Type 1

■ Multi-line Type 2


Figure 4-13: Sample PFD

Single line format lays units in a single line from left to right.

Figure 4-14: Single Line


Drawing Freehand ObjectsPRO/II provides six objects that you can place on the flow diagram tocustomize the look and increase understanding of the flow diagramwithout interfering with simulation data. These objects are:

● Text

● Line

● Polygon

● Rectangle

● Ellipse

● Page

Entering TextYou use the text option to include notes on your drawing. Once youchoose text mode, you remain in text mode as long as you continue tochoose theOK button on theDraw Textwindow; choosing Cancelexits text mode.

To place text:➤ ChooseDraw/Textfrom the menu bar. TheDraw Textwindow ap-

pears.

Figure 4-15: Draw Text Window

➤ Enter the text you want to appear on the diagram.

➤ Optionally, choose a font size for the text. The default is 3.

➤ Choose OK .


Drawing LinesYou use the line option to add connected lines to the diagram withoutinterfering with simulation data. PRO/II provides an orthogonalpolyline feature.

To draw a line:➤ ChooseLine from theDraw menu.

➤ Click and hold the mouse button on the PFD main window to an-chor the line.

➤ Press <Space> to set each anchor point for drawing in a new direction.

➤ Release the mouse button to complete your line.

To draw orthogonal connected lines:➤ ChooseLine from theDraw menu.

➤ Click and hold the mouse button on the PFD main window to an-chor the line.

➤ Press <Ctrl >, and while holding down <Ctrl >, drag the cursor.

➤ Press <Space> to set each anchor point for drawing in a new direction.

➤ Release the mouse button to complete.

Drawing ShapesYou can draw shapes to enclose figures on a diagram withoutinterfering with simulation data.

To draw a polygon:➤ ChoosePolygonfrom theDraw menu.

➤ Click and hold down the mouse button on the PFD main window.

➤ Press <Space> to each anchor point for drawing in a new direction.

➤ Release the mouse button to complete your object.

To draw an orthogonal polygon:➤ ChoosePolygonfrom theDraw menu.

➤ Click and hold the mouse button on the PFD main window.

➤ Press <Ctrl >, and while holding down <Ctrl >, drag the cursor.

➤ Press <Space> to each anchor point for drawing in a new direction.

➤ Release the mouse button to complete your orthogonal polygon.


To draw a rectangle or ellipse:➤ ChooseRectangleor Ellipse from theDraw menu.


➤ Drag and release when you see the desired size rectangle.

To draw a square or circle:➤ ChooseRectangleor Ellipse from theDraw menu.


➤ Press <Ctrl > then drag and release the mouse button to completeyour square.

Drawing PagesYou can divide your PFD into “pages” and define separate page setupoptions for each page. Pages can be individually printed or copied tothe clipboard (see Chapter 3,Managing PFD Files).

To add a page:➤ ChoosePagefrom theDraw menu.

➤ Click on the PFD.

➤ Drag and release the mouse button to the desired size.

The page name is automatically given as PG followed by an autoincrementing three-digit number.

Figure 4-16: Pages


To change the page setup options:➤ Double-click anywhere along the page border. This brings up the

Page Setupwindow.

➤ Select your page setup options.

➤ Click on OK to continue.

After you have set up a page, you can resize it or make this page onecell in a grid of pages.

To resize the page:➤ Click near the page outline to highlight the page.

➤ Click and drag the sizing box.

To move the page:➤ Click and drag the page outline to a new location.

To make a grid of pages:➤ Select the page by clicking near the page outline.

➤ Double-click the left mouse button to display thePage Setupwindow.

➤ Click on the radio button labeledGrid in theChange PageParametersgroup box.

➤ In thePage/Gridgroup box, select the radio button forMultiplePages.

➤ Change the number of rows and columns to make a grid of pageson the PFD. The page you started with will be the upper left cell ofthe grid.

The grid can be resized and moved on the PFD, in the same manner asa single page.


Chapter 5Manipulating Objects

This chapter describes how to select unit icons, streams, and otherobjects on the PFD main window and how to move, resize, rotate, orflip them. In addition, this chapter describes how to edit and align text.

Selecting Objects or Groups of ObjectsYou can select a single object, multiple (noncontiguous) objects, or agroup of objects. Objects or groups of objects include units, streamsand drawn objects. All manipulations (delete, rotate, move) areperformed on selected objects.

Selecting Multiple Objects

You can select a set of noncontiguous objects.

To select a set of individual objects:

➤ Click on the first object.

➤ Press <Shift>.

➤ While holding down <Shift>, click on each object you want to in-clude as part of this set.

Figure 5-1: Multiple Unit Selection Handles

PRO/II User's Guide Chapter 5 Manipulating Objects5-1

Handles appear for the set of objects. For example, although fiveobjects appear to be selected as part of this set (Figure 5-1), when youmove the selection the fourth and fifth objects (the valve and thecompressor) do not move with the set (Figure 5-2).

Figure 5-2: Move Multiple Objects

Selecting a Group of Objects

You can gather a group of contiguous objects by dragging a selectionrectangle around them.

To select a contiguous group of objects:

➤ Click on an unoccupied area of the PFD adjacent to one of theitems you want to select and begin dragging the cursor by movingyour mouse.

➤ Drag the cursor until all desired objects are inside the selection rec-tangle outline.

➤ Release the mouse button to end the selection.

➤ Handles appear for the selected group of objects.

Selecting All Objects

You can select all objects on the flowsheet with one command. Onceselected, you can then move or delete the entire selection.

To select all objects on the flowsheet:

➤ ChooseSelect Allfrom theEdit menu.

Chapter 5 Manipulating Objects PRO/II User's Guide5-2

Deselecting Objects

If you change your mind after selecting objects, you can reverse anyselection.

To deselect or unselect all objects in the layout, do one of the following:

➤ ChooseSelect Nonefrom theEdit menu.

➤ Click on another item or on an unoccupied area of the PFD.

Canceling a Selection Operation

For most operations, you can undo (reverse) the last action. The labelfor theUndocommand changes to indicate the type of operation youcan undo.

To undo any operation, do one of the following:

➤ ChooseUndo from theEdit menu.

➤ Click the right mouse button on an unoccupied area of the PFD.

➤ Press <Esc>.

Resizing an ObjectYou can change the height, width, or overall size of any object or agroup of objects on your flowsheet.

Changing the Size of a Selected Object

When changing the width of a group of objects, you change theabsolute distance between the objects and maintain the relativedistance.

To change the size of an object:

➤ Click and drag the cursor until the object is the desired size.



Figure 5-3: Resize Column

Note: Condensers and reboilers shown on distillation or side columns arefixed in size. They do not resize when you change the size of the column.


Restoring Unit Icon Size

If you don’t like how your resized icon looks (relative to other iconsand objects on your flowsheet) you can quickly return the icon to itsdefault size.

To restore an icon to its original size:

➤ ChooseRestore Icon Sizefrom theEdit menu. You can also clickthe right mouse button on a selected icon, and then chooseRestoreIcon Sizefrom theIcon pop-up menu.

Rearranging Objects or Groups of ObjectsYou can move objects to a different area of the flowsheet. You can alsorotate or flip a unit icon so it fits into the flow of your diagram.

Moving Selected Objects

You can move an object to a new position on the flowsheet.

To move a selected object:

➤ Click and drag the object or group of objects to a new position.


Setting Move Tolerance

Move Tolerancecontrols the incremental distance for any object youmove. The default is 5 pixels.

To change move tolerance:

➤ ChooseDrawing Defaultsfrom theOptionsmenu, thenGeneral.TheGeneral Drawing Defaultswindow appears.

➤ Type the desired value over the defaultMove Tolerance.

➤ Choose OK .

Rotating Selected Objects

You can rotate a selected object(s) on its axis by 90, 180 or 270degrees.

To rotate a selected object:

➤ ChooseRotatefrom theEdit menu. TheRotatedegrees cascademenu appears to the right of theEdit menu.

➤ Choose90, 180, or 270.


Rotating an Icon

You can also click the right mouse button on a unit icon, then chooseRotatefrom thePop-up Unitmenu to display the rotation degrees.

Flipping Selected Objects

You can flip a selected object(s) horizontally or vertically to betterorient the object(s) relative to other objects of the diagram.

To flip a selected object:

➤ Select an object(s).

➤ ChooseFlip from theEdit menu. TheFlip options menu appears tothe right of theEdit menu.

➤ ChooseHorizontalor Vertical.

Flipping an Icon

You can also click the right mouse button on a unit icon, then chooseFlip from thePop-up Unitmenu to display the flip options.

Editing TextYou can change the text, size and or rotation of any text object youplaced on the PFD main window.

To edit text:

➤ Double-click on the text object you want to change. TheDraw Textwindow appears.

➤ Select desired changes and choose OK.

Aligning Text

You can align text in two or more text boxes to the left, right or centerof the box they are drawn in.

To align text:

➤ Select the text you want to align (you must select at least two) byclicking on the first text box, then click on the other box(es) whileholding down the <Shift> key.

➤ ChooseAlign Textfrom theEdit menu. The align menu pop-up ap-pears to the right of theEdit menu.

➤ ChooseLeft, Centeror Right.


Chapter 6Viewing Flowsheet Contents

PRO/II offers a variety of tools that aid you in viewing your flowsheetcontents:

● Horizontal and vertical scroll bars are always available forchanging the visible portion of the process flow diagram in thePFD main window.

● You may open additional viewport windows of your currentflowsheet to display different views of your simulation.

● ThePan Viewwindow is a special feature of PRO/II thatenables you to see a thumbnail of the entire flowsheet and use abounding box in the thumbnail to move the visible area.

This chapter describes how to use the PRO/II scroll, pan, and multipleviewport features to display portions of your flowsheet diagram in thePFD.

Scrolling the PFDYou can scroll the PFD left, right, up, or down using the horizontal andverticalScroll Bars. Both bars enable you to scroll in small or largeincrements or to scroll to a general location.

Setting Scrolling IncrementsYou can change the actual value for the scroll increments by alteringthePan Incrementvalue on theGeneral Drawing Defaultswindow.

ZoomingYou can access the PRO/II zoom features from theViewmenu, usingthe zoom buttons on the toolbar, or using the keyboard.

To zoom in or out, do one of the following:➤ ChooseZoom Inor Zoom Outfrom theViewmenu.

➤ Click on the Zoom icon on the toolbar.

➤ Choose <PgUp> or <PgDn>.

PRO/II User's Guide Chapter 6 Viewing Flowsheet Contents6-1

Zooming In on a Selected AreaYou can specify the exact area of the flowsheet that you want to zoomin on.

To zoom in on a specific area of the flowsheet:➤ Click on the Zoom Area icon on the toolbar or chooseZoom Area

from theViewmenu.

➤ Click and drag the mouse to encompass the desired area within theselection rectangle outline.

➤ Release to complete the zoom area operation. The selected area fillsthe PFD.

Zooming to Show the Full FlowsheetYou can quickly display the entire flowsheet in the PFD.

To use zoom to show the full flowsheet, do one of the following:➤ Click on the Zoom Full icon on the toolbar.

➤ ChooseZoom Fullfrom theViewmenu.

➤ Press <Home>.

Setting the Zoom IncrementYou can change the increment PRO/II uses to zoom in or zoom outwithin theGeneral Drawing Defaultswindow. The default small zoomincrement is 5 pixels and the default large zoom increment is 20 pixels.

Opening Multiple Viewport WindowsYou can open multiple viewports of a single simulation problem todisplay different views of the flowsheet.

To open an additional viewport of the current simulation problem,do one of the following:➤ Click on the Multiple Viewports icon on the toolbar or chooseNew

Viewon theWindowmenu.

Note: If the multiple viewports button is not displayed on your toolbar,check the Standard menu option from the View/Toolbar menu (i.e.,select this option).

Chapter 6 Viewing Flowsheet Contents PRO/II User's Guide6-2

Figure 6-1: Multiple Viewports

Redraw the SimulationYou can use redraw to clear extraneous lines and dots from the PFD.

To redraw the diagram do one of the following:➤ Click on the Redraw icon on the toolbar.

➤ ChooseRedrawon theViewmenu.

➤ Press <Shift+Home>.

PanningYou can pan the contents of the PRO/II main window using thePanwindow or theSmall Panor Large Panoptions on theViewmenu.

ThePan Viewwindow is a thumbprint of the entire flowsheet. Abounding box identifies the area of the flowsheet currently visible inthe PFD main window. You move the bounding box or change its sizeto change how much or what portion of the flowsheet you see in thePFD.

From theViewmenu, you can pan in large or small increments: up,down, left, or right. You can change the settings for the pan incrementin theGeneral Drawing Defaultswindow.


Displaying and Hiding the Pan View WindowTo display the Pan Viewwindow:➤ Click on the Pan View icon on the toolbar or choosePan View

from theWindowmenu.

Figure 6-2: Pan View Window

Panning - Using the Pan View WindowUse the bounding box to change the visible portion of the flowsheet inthe PFD window by moving, enlarging or reducing the bounding box inthePan Viewwindow. The flowsheet in the PFD view changes tomatch the area encompassed by the bounding box.

Moving the Bounding BoxTo move the bounding box:➤ Click the mouse inside the box.

➤ Drag to a new location. The area enclosed fills the PFD.

Note: For a large flowsheet, use the Pan View window to quicklyswitch from one area of the flowsheet to another.

Changing the Size of the Bounding BoxTo change the size of the bounding box:➤ Click and drag the bounding box border handle to enlarge or reduce

the bounding box. The area enclosed fills the PFD.


Panning - Using the Menu OptionsYou can pan the image in the PFD up, down, left, or right using thepanning options on theZoommenu.

To pan the image a large or small amount:➤ ChooseLarge Panor Small Panfrom theViewmenu. The pop-up

menu appears.

➤ ChooseLeft, Right,Up, or Down.

Setting Panning SensitivityYou can change the increment PRO/II uses to pan. The default smallpan increment is 5 pixels and the default large pan increment is 20pixels.


Chapter 7Data Entry Windows

PRO/II offers a wide variety of data entry windows for entering the dataassociated with your PRO/II simulation. There are a number of librariesfrom which you can extract sets of data. This chapter provides an intro-duction to these data entry windows.

Defining the SimulationYou can use the data entry window buttons on the toolbar or the optionson theInput menu to define the scope of the current simulation. PRO/IIidentifies which units are missing data by putting a red border aroundthe unit icon (on the toolbar). For units that are missing productstreams, the identification string for that unit appears in red (on thePRO/II main window).

Defining the scope of the simulation involves:

● Defining the simulation problem

● Selecting the components for the simulation

● Setting the thermodynamic methods for the simulation

Note: Chapter 8, Specifying Component, Thermodynamic and StreamDataandChapter 9, Unit Operations and Utility Modulesprovideexplicit details on the use of the data entry windows introduced in thischapter.

PRO/II User's Guide Chapter 7 Data Entry Windows7-1

A summary of the Data Entry Window buttons available on the PRO/IItoolbar is provided below.


Problem Description Enables you to describe the currentsimulation and relate it to a specificproject.

Units of Measure Enables you to set units of measurespecific to this simulation. Each newsimulation extracts defaults from thedefault Unit of Measure Set.

Component Selection Enables you to specify the componentsand pseudocomponents you want to usein the current simulation

Component Properties Enables you to supply componentproperties.

Thermodynamic Data Enables you to select thermodynamicmethods for the current simulation.

Assay Characterization Enables you to modify TBP Cutpoints andcharacterization options for the generationof pseudocomponents from Assaystreams.

Procedure Data Enables you to supply FORTRAN code forkinetic reaction rate calculations withoutthe need for compilation and linking.

Case Study Specification Allows you to perform studies on a basecase solution by altering parametersselectively and re-running.

Reaction Data Enables you to define reactions andprovide heat of reaction, equilibrium, orkinetic data for reaction sets.

Calculation Sequence Enables you to specify a user-definedcalculation sequence.

Recycle Convergence Enables you to specify user-definedrecycle convergence and accelerationoptions.

Chapter 7 Data Entry Windows PRO/II User's Guide7-2

Selecting ComponentsYou use this option to select the components and pseudocomponentsthat you want to include in this simulation.

To select components for use in this simulation:➤ Click on the Component Selection icon on the toolbar or choose

Component Selectionon theInput menu. TheComponent Selectionwindow appears.

Figure 7-1: Component Selection

➤ Select a component from the available lists or type the name of thecomponent. Each component you select appears in theList of Se-lected Componentsbox on the right side of the window.

Modifying Component PropertiesYou can use this option to modify fixed component properties or usetheFill from Structuresfeature to fill in missing component data forlibrary or user-defined components.

To modify component properties:➤ Click on the Component Properties icon on the toolbar or choose

Component Propertiesfrom theInput menu. TheComponent Prop-erty Modificationwindow appears.


Figure 7-2: Component Property Modification

Selecting Thermodynamic MethodsYou use the thermodynamic data option to choose the thermodynamicmethod(s) for this simulation.

To set thermodynamic calculation methods for this simulation:➤ Click on the Thermodynamic Data icon on the toolbar or choose

Thermodynamic Dataon theInput menu.

Figure 7-3: Thermodynamic Data

You can specify a predefined system of thermodynamic calculationmethods.

➤ Select a category of predefined systems. PRO/II displays the prede-fined systems for this category in thePrimary Methodlist box.

➤ Select a predefined system from thePrimary Methodlist box.

➤ Choose Add-> to define the calculation method.


Selecting Assay DataYou use this option to modify the data obtained from the selected AssaySet.

To select assay data for this simulation:➤ Click on the Assay Characterization icon on the toolbar or choose

Assay Characterizationon theInput menu.

Figure 7-4: Assay Cutpoints and Characterization

PRO/II always supplies the Primary TBP Cutpoint set. You can modifythe primary set or define a new cutpoint set or set characterizationoptions.

Specifying Reaction DataYou use this option to define reactions and enter heat of reaction, equi-librium, or kinetic data for reaction data sets.

To specify reaction data sets for this simulation:➤ Click on the Reaction Data icon on the toolbar or choose

Reaction Dataon theInput menu.


Figure 7-5: Reaction Data

Specifying Procedure DataYou use this option to create procedure blocks to calculate kineticreaction rates. You are able to supply FORTRAN code for the reactionrate calculations without the need for compilation and linking.

To select procedure data for this simulation:➤ Click on the Procedure Data icon on the toolbar or choose

Procedure Dataon theInput menu.

Figure 7-6: Procedure Data


Specifying Multiple Simulations for Case StudyYou use this option to make changes to input data and then examine theeffect of those changes on the values of calculated data or functions ofcalculated data.

To select case study data for this simulation:➤ Click on the Case Study icon on the toolbar or chooseCasestudy

Data on theInput menu.

➤ Check theDefine Case Studybox.

Figure 7-7: Case Study Specification

Setting the Problem Calculation SequencePRO/II performs a simulation by solving one unit operation at a time,following a certain calculation sequence to reach the problem solution.You use this option to specify the method to determine this calculationsequence for the current problem.

To select calculation sequence for this simulation:➤ Click on the Calculation Sequence icon on the toolbar or choose

Calculation Sequenceon theInput menu.


Figure 7-8: Problem Calculation Specification

Specifying the Recycle ConvergenceYou use this option to override the recycle loop sequence determined byPRO/II, and to specify acceleration methods and convergencetolerances for individual loops.

Note: This window is not available if you select the SIMSCI method forCalculation Sequencing, since the loops are determined automaticallyby this method.

To select recycle convergence for this simulation:➤ Click on the Recycle Convergence icon on the toolbar or choose

Recycle Convergenceon theInput menu.


Figure 7-9: Recycle Convergence Options

Data Entry Windows for Unit OperationsThe data entry window for any unit operation can be accessed by high-lighting the unit on the PFD and selecting theInput/Data Entryfromthe menu bar. Numerous types of data entry devices are used to supplynumeric values and select calculation options in PRO/II, including:Push Buttons, Radio Buttons, Check Boxes, Edit Fields, Spin Buttons,Standard List Boxes, Drop-Down List Boxes, GridandX-Y Grid,Combo Boxes, Drop-Down Combo Boxes,andLinked Text.

Most main data entry windows provide Help, Overview, and Status buttonsthat enable you to access different levels of help text. In addition, somemain data entry windows (and some subordinate windows) provide UOM,Define and Range buttons. Grayed buttons indicate that the feature is notcurrently available.


Button Description

Displays context sensitive help for the active data entry field, or forthe window itself (if there is no active field).

Displays the main help window for the data entry window.

Displays the results of the data consistency checks performed forthe main window after you choose OK.

Selects a units of measure set for the selected data entry field.

References one stream or unit parameter value to another streamor unit parameter.

Displays the valid range of values for the active data entry field.

Grids and the X-Y GridGrids are used to supply data in tabular form. There may be severalrows of related data entries.X-Y Gridsare a special type of grid thatare used to supply data for relational curves. The two grid columnscontain an independent variable (x) and one related dependent variable(y).

TheColumn Tray Hydraulicswindow shown below is an example of agrid. Notice that it provides columns for the starting tray number, endingtray number, calculation type, and entry of tray data. Each row has anumberedclick buttonwhich is used to select the row for toolbar actions.For this example, several types of data entry devices are used in the grid.The starting and ending tray numbers areinteger edit fields, the calculationtype is adrop-down list box, and the entry of tray data is aclick button,which brings up theColumn Tray Sizingwindow orColumn Tray Ratingwindow, depending on the calculation type that was selected.


Figure 7-10: Column Tray Hydraulics Window

Observe that five rows are provided in the initial grid corresponding tofive sections in the column. This may be expanded by clicking a rownumber button and then clicking theInsert button far left. A row willbe added below the selected row. When the number of rows exceedsfive, a scroll bar appears at the right side of the grid to provide access tothe rows not displayed. To deselect a row, click the number button ofthe previously selected row, or select a different row. To clear dataentries from a row, click the row number button and then click the

Reset button. To remove a row, click the row number button and theCut button.

As another example, theCompressor Outlet Pressure Performancewindow shown below contains an X-Y grid for a user-suppliedcompressor pressure curve.


Figure 7-11: Compressor Outlet Pressure Performance Window

Notice that two columns are used for the pressure curve. The firstcolumn is the volumetric feed rate and the second column is the corre-sponding outlet pressure from the compressor. Four individual entriesor cellscorresponding to two rows in the table are marked with a redborder as mandatory input. Optionally, more pairs of information may beprovided.

The initial grid displays four pairs of cells. Note that each row in thegrid has a numbered click button which may be used to select the row.The initial table may be expanded with theInsert button on thetoolbar as described in the previous example. When the number ofrows in the X-Y grid exceeds four, a scroll bar appears to provideaccess to rows not displayed.

A row may be deleted from the grid by clicking its number button andthen clicking the Cut button. To copy a row, first click its numberbutton and then click theCopy button. The row is copied into theclipboard. Next, click the row number button for the row which will bejust below the copied row. Complete the copy by clicking thePastebutton to insert a copy of the row from the clipboard.


Linked textLinked textis used to input information in a sentence format. Numericvalues, mathematical operators, stream or unit names, or variousoptions may be supplied as linked text. Linked text may serve to accessanother data entry device. TheFeedback Controllerdata entry windowcontaining linked text is shown in Figure 7-12.

Figure 7-12: Feedback Controller Main Data Entry Window - Initial Display

Linked text is used on this window to define theSpecificationandVariable. Note that the Parameterand valuelink texts are red, denotingthat you must click these strings and provide data entries. The textstring the default toleranceis green, denoting a default value.

Optionally, a different tolerance may be provided by clicking the afore-mentioned text string to open theSpecification Tolerancewindowwhere the appropriate radio button may be clicked to select a newtolerance type, i.e., relative tolerance. ClickOK to return to theFeedback Controllerwindow. Notice that the relative tolerancetextstring becomes blue indicating a user-supplied value.

When the valuetext string is clicked, a floating point entry field for thespecification value is displayed with a red border signifying mandatoryinput. The value you supply is now displayed in blue numbers insteadof the valuetext string.

Clicking the Parametertext string retrieves theParameterwindow inwhich the unit or stream and its parameter are defined. The unit orstream identifier and the parameter for the specification are nowdisplayed in blue, replacing the Parametertext string.


Figure 7-13: Feedback Controller Data Entry Window - Final Display


Chapter 8Specifying Component,

Thermodynamic and Stream DataThis chapter describes several types of optional component, thermody-namic and stream information which may be supplied for PRO/II. Inmany cases, the default values are satisfactory and it may not be necessaryfor you to visit these sections.

Component DataGeneral InformationPRO/II provides considerable flexibility in the definition of componentdata. No limit is set on the number of components which may be usedfor any problem. Furthermore, component data may originate from avariety of sources such as SIMSCI databanks, user-prepared databanks,user-defined components, and components derived from petroleumassay data for feed streams. Moreover, you may stipulate a preferentialsearch order when multiple databanks are used.

The SIMSCI databanks, SIMSCI and PROCESS contain more than1700 components and are adequate for nearly all simulation models.The AIChE DIPPR databank is also available as an add-on to PRO/II.User databanks of thermophysical data can be created, using SIMSCILIBMGR and DATAPREP programs, and maintained through PRO/IIgraphical user interface. SIMSCI REGRESS is also fully supported inPRO/II, allowing you to carry out regression of experimental thermo-physical data to model equations.

Selecting Library ComponentsYou may select library components, from both SIMSCI and user-supplied databanks, through theComponent Selectionmain data entrywindow. To open this window from the PRO/II main window:

➤ Click the Component Selection icon on the toolbar, or select themenu bar itemInput/Component Selection. TheComponentSelectionwindow appears.

If you know the library access name for a component, you may enter itdirectly into the data entry field. ClickAdd-> or press <Enter> toretrieve the component from the component databank and add it to theList of Selected Components. If the component cannot be located by the

PRO/II User's Guide Specifying Component,Thermodynamic and Stream Data8-1

name you have entered, a warning will recommend that you use theSelect from Lists…feature to locate the component in the SIMSCI andPROCESS databanks:

➤ Click the Select from Lists… button on theComponent Selectionmain data entry window to open theComponent Selection -List/Searchwindow.

➤ Select aComponent Familyfrom the like-named drop-down listbox. A large number of component families are provided to speedthe search. A brief description is given below:

Most Commonly Used: Approximately 100 components representing all ofthe pure components commonly encountered in natural gas andpetroleum processing.

Hydrocarbon Lightends: Light gases commonly reported on analyses for oilrefinery streams.

All Components: Every component in the SIMSCI and PROCESSdatabanks.

Families of Specific Chemical Type: Twenty families in alphabetical order:

Acids Additional Electrolyte ComponentsAlcohols AldehydesAmides AminesAromatic Hydrocarbons ElementsEsters EthersHalogenated Derivatives KetonesMiscellaneous Naphthenic HydrocarbonsOther Nitrogen Derivatives Paraffinic HydrocarbonsSalts and Minerals Silicon DerivativesSulfur Derivatives Unsaturated Hydrocarbons

For all families listed above, except for Hydrocarbon Lightends, youmay define specific search criteria by selecting radio buttons andentering a search string. Use part or all of the component name, alias,or chemical formula as the search string. As components are located,transfer them to theAdditions to Component Listbox. When you havelocated all the components, clickOK to return to theComponentSelectionmain window and to transfer the components to theList ofSelected Components.

The priority order for databanks may be defined by pushing theDatabank Hierarchy button on theComponent Selectionmain window

to access theComponent Selection – Databank Search Orderwindow.This window initially displays the default search order and may bemodified to search the databanks in any order. Components are always

Specifying Component,Thermodynamic and Stream Data PRO/II User's Guide8-2

selected from the first databank in the search order in which theyappear.

Entering User-defined ComponentsYou may want to enter a component as a user-defined component whenyou wish to use a component that is not in the PRO/II library.

➤ Enter user-defined components by clickingUser-defined… on theComponent Selectionmain window to access theComponentDefinition - User Definedwindow.

➤ Type in the name of the user-defined component in theComponentNameentry field.

➤ Click OK to commit the new component name.

Note: At this point, you haveonly entered thenameof the user-definedcomponent in the database. Now you must supply thepropertiesfor thecomponent by the steps described below in Modifying Component Proper-ties.

Defining Petroleum (PETRO) ComponentsDefine PETRO components by pushing thePetroleum… button on theComponent Selectionmain window to access theComponent Selection– Petroleum Componentswindow. You may define any number ofPETRO components in a single visit to this window by using thetabular input provided.

You must supply at least two of the three correlating properties,normalboiling point, standard liquid density, andmolecular weightfor eachcomponent. Names may be optionally provided or will be supplied byPRO/II as NBP XXX where XXX is the component normal boiling point.PRO/II uses internal correlations to estimate the third parameter, whenmissing.

All necessary physical and thermodynamic properties are computedfrom the three correlating properties. Molecular weight is the mostdifficult property to predict accurately from generalized correlationsand should be supplied when possible for the most accurate characteri-zation for a PETRO component.

Note: It is not possible to enter data for assay pseudocomponents (whichare based on stream assay information) with this window. All propertiesfor components derived from assay data are automatically defined byPRO/II. The components are also added to the component list by PRO/II.


Defining Solid ComponentsYou can enter input solids characteristics directly into PRO/II. You mayspecify stream properties, the particle size distribution, and the particleproperties. PRO/II also allows you to input experimental solids solu-bility data.

To add a solid component to the flowsheet:➤ Click on theComponent Selectionicon or selectInput/Component

Selectionfrom the menu bar to open theComponent Selectionwin-dow.

➤ Click the Component Phases… button. Ensure that the compo-nents that may be solid have the solid phase enabled.For example,if you enter NaCl for use in a dissolver, make sure that its compo-nent phase designation is “liquid-solid”.

If the flowsheet will include unit operations that require particle sizedistributions (e.g., Cyclone, Dissolver, Crystallizer),Input/ComponentProperty Data from the menu bar. In the like-named window, clickParticle Size Distribution… to open theParticle Size Distribution forSolidswindow. Enter PSD cutpoints for all relevant solid components.Particle size grades are bounded by the cutpoints that are entered here.Grades will not be created on the open ends of the first and lastcutpoints (i.e., if the cutpoints are 10 and 20 microns, there will be onegrade of 10 to 20 microns,not three grades of less than 10, 10 to 20,and greater than 20 microns).

To change the units of measure for the particle size distribution, click inany of theDistribution Rangesentry fields to enable theUOM buttonin the toolbar at the top of the window.

Deleting and Renaming Component PropertiesCurrently, actions on components that appear in theList of SelectedComponentsin theComponent Selectionmain window are limited to deletionor renaming of components.

To delete a component:➤ Highlight the name of component in theList of Selected

Components.

➤ Click Delete .

To rename a component for printout purposes:➤ Highlight the component.

➤ Click Rename… to open theRename a Componentwindow.

➤ Enter the new name in the data entry field.


Modifying Component PropertiesYou can modify properties for any component entered through theComponent Selectionmain data entry window via theComponentProperty window. To reach this window:

➤ SelectInput/Component Properties...from the menu bar or click onthe Component Properties icon on the main toolbar.

TheComponent Propertieswindow is the master navigation point forchanging all component properties.

Note: Component properties cannot be defined before the componentnames have been entered.

There are three methods available for component propertymodification:

Method 1: Specifying Fixed PropertiesClick Fixed… to open theComponents Properties-Fixed Propertieswindow. Here you can modify fixed component properties such asmolecular weight, critical temperature and NBP. With the exception ofassay components, all components can be modified via this window.For those properties having UOMs, all data is displayed with the UOMsof the current problem.

Starting from this window, use the appropriate button to modify otherproperties:

➤ Click Critical Properties… to specify critical temperature, criticalpressure, critical volume and critical compressibility factor.

➤ Click Molecular Constants… to specify properties such as DipoleMoment, Radius of Gyration, van der Waals Area parameter andvan der Waals Volume parameter.

➤ Click Heats of Formation… to specify Enthalpy of Formation andGibbs Energy of Formation. In this entry, reference phase designa-tion is a required input. The reference phase can be vapor, liquid orsolid. Vapor phase is the default.

➤ Click Miscellaneous Properties to specify Acentric Factor,Solubility Parameter, RackettParameter, Liquid Molar Volume, Heatof Vaporization, Heat of Fusion, Normal Melting Point, Triple PointTemperature, Triple Point Pressure, Heat of Combustion, Gross Heat-ing Value, Lower Heating Value, Carbon Number and Hydrogen Defi-ciency Number.


For PRO/II library components, the values in the database will appearin the various property windows. In cases where there is no libraryvalue to serve as the default, the default displayed will be the text“Missing.” You may reassign values for any of these properties.

Method 2: Specifying Temperature-Dependent PropertiesYou may enter or override default data for properties that change withtemperature, such as density and viscosity, for the vapor, liquid or solidphases of the pure components in your simulation. You may supply newdata in the form of tables or as correlation coefficients of one of 29different equation types.

Click Temperature Dependent to open theComponent Properties -Temperature Dependent Propertieswindow. All the library and user-defined components from the current problem are displayed. To enteror modify data for a property of a component, click on thecorresponding push button for that component. For properties that mayapply to more than one phase, you will first be required to select thephase for which you are to supply data in theComponent Properties -Phasewindow,

➤ Click VP to enter or modify liquid or solid vapor pressure data.

➤ Click H to enter or modify vapor, liquid or solid enthalpy data.

➤ Click Cp to enter or modify solid heat capacity data.

➤ Click ∆Ην to enter or modify latent heat data.

➤ Click ρ to enter or modify liquid or solid density data.

➤ Click µ enter or modify vapor or liquid viscosity data.

➤ Click κ to enter or modify vapor, liquid or solid conductivitydata.

➤ Click σ to enter or modify liquid surface tension data.

In theComponent Properties - Data Source Selectionwindow choosethe method of data entry. You may enter data either in tabular form oras coefficients for one of as many as 29 equations.

If you choose theCorrelation Coefficientsoption, you may display theform of the equation by selecting the appropriateCorrelation Numberin the like-named drop-down list.

➤ Select one of the correlations and supply coefficients as required.If the form of the equation is logarithmic, you may select the baseof the logarithm. You may change the units of the equation andmay impose maximum and minimum temperatures of applicability.


Note: The full range of equations can be found in the online PRO/IIReference Manual accessible via the Help system. If you choose anequation that is not standard, a message to that effect appears, and theborder of the drop-down list box will be yellow.

If you choose theTabular Dataoption, the Component Properties -Tabular Data window appears.

➤ Enter temperature and property data. You must enter at least onedata pair.

DATAPREPThe most commonly used features of DATAPREP, particularly relatingto point properties and temperature-dependent correlations for purecomponents, are now accessible in the graphical user interface ofPRO/II. PRO/II allows you to input data, view database correlationinformation, override database information as desired, and plot parame-ters over a temperature range.

Method 3: Specifying Fill From StructureThe Fill from Structure button opens theComponents Properties - Fillfrom Structurewindow. TheAvailable Componentslist on the left handside contains library and user-defined components from the currentproblem. You may add or remove components to be filled fromstructure to the like-named list on the right. ClickOK to have theproperties of the selected components filled from structure.

PRO/II predicts properties from structure using established correlationsand techniques. Joback (1985) significantly expanded the work ofLyderson (1955) in this area providing a group contribution method forthe prediction of critical properties, boiling point, freezing point, idealgas capacity, enthalpy and Gibbs heat of formation. Joback used alarge database of components to statistically determine group parame-ters for 42 different functional groups. SIMSCI has extended this workto include several missing parameters.

To complete theFill from Structureprocedure, click theUNIFAC Structures… button on theComponent Propertieswindow to

display the like-named window. A UNIFAC Structure entry ismandatory for all components for whichFill from Structurehas beenrequested. Click theUNIFAC Structures… button adjacent to thecomponent of interest to open theDefine UNIFAC Structurewindowwhere you may choose from families of components or from theUNIFAC group number directly.


Assay DataGeneral InformationFor many petroleum-based streams, the composition is not fully knownin terms of defined components. These stocks must be characterized bypseudocomponents for which the necessary physical and thermody-namic properties have been estimated. PRO/II has extensive proceduresfor translation of petroleum stream laboratory assay data intopseudocomponents.

Pseudocomponents are based on boiling point or “cutpoint” ranges on thetrue boiling point (TBP) distillation for the stock. The normal boiling pointfor a pseudocomponent is defined as the weighted average temperature ofits cutpoint range. The TBP distillation must often be derived from anothertype of laboratory distillation, using a conversion procedure. PRO/IIaccepts the following types of laboratory distillations: TBP, ASTM D1160,ASTM D86, and ASTM D2887. While laboratory distillations are usuallyreported on a 760 mm Hg basis, PRO/II has procedures to correct distilla-tions for other laboratory pressures.

Estimated values for the standard liquid gravity and molecular weightfor each pseudocomponent are also needed for the characterizationprocess. The standard liquid gravity for each pseudocomponent isderived from the gravity curve for the stream, in similar fashion to thenormal boiling point. The gravity curve for the stream is often notavailable, and it must be estimated, based on the average stream gravityand the distillation curve. The molecular weight curve is seldomavailable, and the molecular weight for each pseudocomponent isusually predicted from its normal boiling point and standard liquidgravity. All other required physical and thermodynamic properties maybe estimated from the normal boiling point, standard liquid gravity, andmolecular weight.

The use of assay data in PRO/II is divided into two logical steps. Thefirst step involves the definition of the cutpoint ranges and selection ofthe characterization options used in development of the pseudocompo-nents. Characterization options include distillation curve fitting andconversion methods, gravity curve generation procedure, methods forprediction of molecular weight, and methods for estimation of criticalproperties and ideal gas enthalpies. If the default cutpoint ranges andmethods furnished by PRO/II are acceptable, this step may be omitted.

The properties for all pseudocomponents derived from the samecutpoint set are averaged, based on the stream flows, to develop a commonset of blend components. This technique provides reasonable results whenthe streams have similar chemical natures. For example, all of the assay


streams are products from the crude distillation unit. However, whenassay streams are dissimilar chemically, such as virgin materials andcracked materials, there may be serious errors in the characterizationsfor the streams when a single set of blend components is used.

For this reason, you are allowed to define additional cutpoint sets. Forexample, an additional cutpoint set may be defined to represent theproducts from an FCC reactor. Note that it is not necessary or desirableto define a separate cutpoint set for each assay stream. Similar streamsmay be grouped by using the same cutpoint set without a serious loss ofaccuracy. This also minimizes the number of components in the simula-tion, keeping calculation times smaller.

The second step is supplying the petroleum stream laboratory assaydata to PRO/II. This step is accomplished in the setup of initial feedstreams and is discussed in theStream Datasection of this chapter.

TBP Cutpoint SetsTBP cutpoint sets are defined in theAssay Cutpoints and Characteriza-tion main data entry window. This window may be reached from thePFD main window in two ways:

➤ Click the Assay Characterization icon with the distillation pseudo-component curve on the toolbar, or select the menu bar itemInput,then select the menu itemAssay Characterization.

A Primary Cutpoint Setis always provided as a default by PRO/II.This set has the following cutpoint definitions:

Cutpoint Range, Deg F Cutpoint Range, Deg C No of Cuts

100 - 800 38 - 427 28

800 - 1200 427 - 649 8

1200 - 1600 649 - 871 4


The default cutpoint ranges are usually reasonable for crude oilproblems. They may be modified in theAssay Data Primary TBPCutpoints Definitionwindow which is accessed by clicking theModify...button on theAssay Cutpoints and Characterizationmain data entrywindow. A convenient tabular form is provided for editing of the primarycutpoint set.

Additional orSecondarycutpoint sets may be added to the problem byclicking the Define New Cutpoint Set... button on theAssay Cutpointsand Characterizationmain data entry window to access theAssay DataSecondary Set of TBP Cuts.A cutpoint set name is supplied on thiswindow and a tabular entry form is provided for definition of thecutpoints. This window is also used to modify existing secondarycutpoint sets and is presented when the Modify button on theAssayCutpoints andCharacterizationmain data entry window is clicked and asecondary cutpoint set has been highlighted in theDefined Secondary Setslist box on theAssay Cutpoints and Characterizationmain data entrywindow.

Highlighted secondary cutpoint sets in theAssay Cutpoints and Char-acterizationmain data entry window may be deleted by clicking the

Delete... button. This action removes the secondary cutpoint set fromthe problem.

TheDefault Cutpoint Setis used for all streams for which a cutpoint setis not specified. Initially, it is defined as thePrimary Cutpoint SetbyPRO/II. After one or moreSecondarycutpoint sets have been defined,the default cutpoint set may be changed via the drop-down list box ontheAssay Cutpoints and Characterizationmain data entry window. Itis convenient to define the cutpoint set which is used the most often asthe default cutpoint set.

Assay Characterization OptionsAssay characterization options are selected on theAssay Characteriza-tion Optionswindow which is reached by clicking theCharacterizationOptions button on theAssay Cutpoints and Characterizationmain dataentry window. Several groupings of options are shown in this window,with all options selectable with radio buttons. The option groups are asfollows:

Criticals, Ideal-Gas Enthalpy: SIMSCI (Twu) method (the default), Cavettmethod, or Lee-Kesler method.

Molecular Weight: SIMSCI (Twu) method (the default), Old (1967) APImethod, or Extended 1980 API method.


Gravity Curve Generation Method: Constant Watson K from TBP Curve(default), or Constant Watson K from D86 Curve.

D86/TBP Conversion Method: API 1987 (the default), API 1963, API 1994,or Edmister-Okamoto.

Distillation Curve Fitting Procedure: Cubic Spline (default), QuadraticPolynomials, or Probability Density Function (PDF).

Distilllation Boundaries: Initial Point and End Point percentages.

Include in PDF: Include initial boiling point in fit, and/or include endpoint in fit.

Calculation of NBP for Cuts: Liquid Volume Average (default) or Tempera-ture Midpoint.

The characterization options are explained in greater detail in thePRO/II help text and the onlinePRO/II Reference Manualaccessed viatheHelp menu.

Thermodynamic DataGeneral InformationThe selection of appropriate thermodynamic methods is an importantand necessary step in the solution of flowsheet problems. PRO/IIprovides a wide range of methods to allow solution of the wide varietyof systems which occur in the chemical process industries.

Thermodynamic properties are an integral part of the flowsheet calcula-tions. The equilibrium K-values (both VLE and LLE) are used todetermine the phase separations. The enthalpies for the streams are usedto determine the energy required to take a system of components fromone set of thermal conditions to another. Entropies are used in thecalculation of the isentropic operations and the Gibbs free energy mini-mization reactor. Liquid and vapor densities are used in heat transfer,pressure drop, and column tray sizing.

Transport properties are selected in conjunction with the thermody-namic methods in PRO/II and are comprised of liquid and vaporviscosities, liquid and vapor thermal conductivities, and liquid diffusivi-ties. While not strictly a transport property, liquid surface tension isalso included. Transport properties find use in rigorous heat transfercalculations, pressure drop determination, and column sieve tray andpacking calculations. Transport properties are also reported in thestream properties reports and may be requested inHeating/CoolingCurvesreports.


In PRO/II, the selection of thermodynamic methods has been simplifiedby the concept of themethod set. Method sets consist of predefinedthermodynamic methods for K-values (VLE and LLE), liquid and vaporenthalpies, entropies, vapor fugacities, and densities. Numerous prede-fined sets are provided. Multiple thermodynamic method sets may beselected for each flowsheet. For example, a default set may be specifiedfor the overall flowsheet and other method sets used for individualunits.

A facility is also provided to modify the thermodynamic methods in thepredefined method sets. Certain parameters for some of the thermody-namic methods may also be supplied.

Selecting Predefined Method SetsSelection of thermodynamic method sets is accomplished via theThermo-dynamic Datawindow which may reached from the PFD main windowin two ways:

➤ Click the Thermodynamic Data icon with the phase diagram on thetoolbar or select the menu bar itemInput/Thermodynamic Data.

For convenience, severalCategoriesof method sets can be selected inthe list box on theThermodynamic Datawindow. ThePrimaryMethod, i.e., the method used for calculation of equilibrium K-values,for each method set in the selectedCategoryappears in a drop-downlist box and may be selected to add the method set to theDefinedSystemsfor the problem.

The Defined Systems appear in a list box and each may be selected forfurther action by highlighting the desired method and clicking thebuttons: Modify... , Delete... , and Rename... on the Thermody-namic Data window. The method set for which action is to be taken isselected (highlighted) in the Defined Systems list box. Delete removesthe selected method set from the problem. The Rename option is usedto change the name of the selected method set. This is useful when it isdesired to use a method set more than one time in a problem, perhapswith different parameters. Modification of method sets is discussedlater in this section.

The followingCategoriesof method sets are provided:

Most Commonly Used: These method sets may be used for a wide variety ofproblems. Nearly all gas processing and oil refining calculations arehandled satisfactorily. Method sets in this category are: Soave-Redlich-Kwong (SRK), Peng-Robinson (PR), Grayson-Streed (GS),Braun K-10 (BK10), Ideal, NRTL, UNIQUAC, and UNIFAC.


Equations of State: Equations of state are applicable to wide ranges oftemperatures and pressures. They can be used to calculate all ther-modynamic properties, using the ideal gas state as the referencestate. The cubic equations, in particular, are able to accurately pre-dict critical and supercritical conditions. Equation of state methodsets are: Soave-Redlich-Kwong (SRK), SRK-Kabadi-Danner(SRKKD), SRK-Huron-Vidal (SRKH), SRK-Panagiotopoulos-Reid(SRKP), SRK-Modified-Panagiotopoulos-Reid (SRKM), SRK-SIMSCI (SRKS), SRK-Hexamer (HEXAMER), Peng-Robinson(PR), PR-Huron-Vidal (PRH), PR-Panagiotopoulos-Reid (PRP),PR-Modified-Panagiotopoulos-Reid (PRM), BWRS (BWRS),Lee-Kesler-Plöcker (LKP), and Uniwaals (UNIWAALS).

Liquid Activity: Liquid activity methods use liquid phase activity coeffi-cient models to represent the liquid mixture in phase equilibriumcalculations. This approach is useful for modeling strongly non-ideal liquid solution behavior. Methods available in PRO/II include:NRTL, UNIQUAC, Wilson, van Laar, Margules, Regular Solution,Flory-Huggins, UNIFAC, UNIFAC TDep-1, UNIFAC TDep-2,UNIFAC TDep-3, UNIFAC Free Volume, and Ideal.

Generalized Correlations: Generalized correlations predict K-values withsemi-rigorous equations. The Grayson-Streed and Chao-Seadercorrelations use the Redlich Kwong equation for vapor fugacitiesand empirical relationships for the liquid fugacities. Braun K-10 isbased on the convergence pressure concept. A variety of other cor-relations are used to predict the other properties, i.e., enthalpies, en-tropies, and densities. Generalized correlations are: Braun-K10(BK10), Grayson-Streed (GS), Improved-Grayson-Streed (IGS),Grayson-Streed-Erbar (GSE), Chao-Seader (CS), Chao-Seader-Erbar (CSE), and Ideal (IDEAL).

Special Packages: Special packages are designed to solve a particularindustrial application. Special packages in PRO/II are: Alcohol(ALCOHOL), Glycol (GLYCOL), Sour Water (SOUR), GPA SourWater (GPSWATER), and Amine (AMINE).

All Primary Methods: This category includes all of the primary thermody-namic sets that are listed above.

User-added Methods: This category includes all of the 15 user-addedmethod sets that may be defined by the user.

The PRO/II online help texts provide application guidelines for thevarious method sets, as well as a brief description for each method.More detailed information may also be found in thePRO/II ReferenceManual(also available online). Table 8-1 at the end of this section


gives a detailed list of the composite thermodynamic methods used foreach predefined method set.

Modifying Predefined Method SetsPredefined method sets are modified via theThermodynamic Data-Modificationwindow which is accessed by clicking theModify...button on theThermodynamic Datawindow.

The preselected thermodynamic methods for the various thermody-namic properties may then be changed in this window by followingthese steps:

➤ Click on theCurrent Methoddrop-down list box corresponding tothePropertytype.

➤ Select the replacement thermodynamic method.

Any or all of the thermodynamic methods may be changed for themethod set being modified, including: K-value (VLE), K-value (LLE),liquid enthalpy, vapor enthalpy, liquid entropy, vapor entropy, liquiddensity, vapor density, and vapor fugacity (where applicable).

Some property specificdata may also be supplied and/or modified in thiswindow for the thermodynamic methods by clicking on theEnter Data...button in theProperty-specific Datafield. Many of the methods usespecific parameters, such as binary interaction factors, modified acentricfactors, etc. A priority search order may be defined for selection of theseparameters from more than one thermodynamic databank. Note that ther-modynamic databanks are supplied by SIMSCI and may also beprepared by the user with the SIMSCILIBMGRprogram.

Property specific data which apply only to the liquid activity methodsinclude: fill options for missing parameters, Henry’s Law options, andPoynting correction options. For the liquid activity methods, a vaporfugacity method may also be selected.

Other property-specific data which may be modified include the dimen-sionless residence time correction factor for amines DGA and MDEAand the key (or dominant) components in each liquid phase for K-value(LLE) methods. Key component selection is optional and PRO/II willdetermine them when not supplied; however, convergence time may beenhanced by preselection of the key components.

Fill-In Property Prediction

PRO/II allows missing data to be “filled in” under several circumstances.For example, when the composition of an azeotrope and activity coefficientvalues at infinite dilution are known for some pair of species, you can use


this option to predict missing activity coefficient values at intermediateconcentrations.

VLE and LLE K-value parameters for liquid activity coefficientmethods may be estimated by the UNIFAC, Temperature-DependentUNIFAC, Regular Solution, or Flory-Huggins methods, or they may beobtained from an azeotrope bank. The choice of fill-in property predic-tion is entered on theBinary Data Fill Optionswindow, which isreached by clicking the correspondingEnter Data... button on theThermodynamic Property Modification-Property Specific Datawindow.Checking the box will fill in missing data from the azeotrope databank.A method for filling in missing binary parameters (using the UNIFAC,modified UNIFAC, Regular Solution, or Flory-Huggins methods) maybe selected by choosing the appropriate radio button.

Equation of State Alpha Data

The form to be used for equation of state alphas may be specified ontheAlpha Selectionwindow. This window is reached by clicking theappropriate Enter Data... button on theThermodynamic PropertyModification-Property Specific Datawindow. The source of the alphasto be used in the equation of state may be designated by selecting theappropriate radio button.

Henry�s Law

The Henry’s Law window is used to specify whether or not Henry’sLaw is to be used in conjunction with a liquid-activity K-value method.This window is brought up by clicking on the appropriateEnter Data...button on the Thermodynamic Property Modification-Property SpecificData window. Checking the box on the Henry’s Law window causesHenry’s Law to be used to determine the solubility of certain compo-nents. Designation of solute components may either be determined bythe program or selected explicitly, by choosing the appropriate radiobutton. If the solute components are to be designated explicitly, thedesired solute components must be selected from the list box on theHenry’s Law window.

Poynting Correction

ThePoynting Correctionwindow is used to specify the use of thePoynting correction factor for liquid-phase fugacities. ThePoyntingCorrectionwindow is brought up by clicking the appropriateEnterData... button on theThermodynamic Property Modification-PropertySpecific Datawindow.

There are three options for the usage of the Poynting correction:


1. Default: This choice specifies that the Poynting correction willbe used only if a vapor fugacity method is chosen.

2. Use Poynting Correction to Liquid Activities: Use thePoynting correction factor for the liquid phase fugacity.

3. Do Not Use Poynting Correction: Do not use Poyntingcorrection factor.

If either of the first two options is selected, then the molar volumecalculation method may be selected from the following choices:Standard (25°C) Volumes, Rackett, Rackett One-Fluid, or LibraryDensity Correlations. The default method isStandard (25°C) Volumes.

Amine Residence Time Correction Factor

TheAmine Residence Time Correctionwindow is available only for theAmine special data package thermodynamic method for K-values. It isaccessed by clicking theEnter Data... button on theThermodynamicProperty Modification-Property Specific Datawindow, then on theLLE KeyComponents... button on the LLE K-values window. A value for theresidence time correction factor for systems containing amines MDEA orDGA may be entered in this window. The default value for this factor is0.30.

LLE Key Components

TheLLE Key Componentswindow can be accessed whenever an LLEK-Value method is selected, by clicking the appropriateEnter Data...button on theThermodynamic Property Modification-Property SpecificData window, then on theLLE Key Components... button on theLLEK-valuewindow. Both the light liquid phase and the heavy liquid phasecan either beDetermined During Calculationsor User-Specifiedbyselecting the appropriate radio buttons. When theUser-Specifiedradiobutton is chosen, a component must be selected in the associateddrop-down list box. This drop-down list contains all available liquid-phase components. One component may be selected for each key.

Binary Interaction Parameters

A number of methods in PRO/II allow the entry of binary interactionparameters. These include equations of state for many properties andliquid-activity-coefficient models for K-values. These parameters areentered on theBinary Interaction Parameterswindow, which is reachedby clicking the Enter Data... button next toBinary InteractionParameterson theThermodynamic Property Modification-PropertySpecific Datawindow. For each column of the grid, the two compo-


nents for which the data is being entered must first be selected from thedrop-down list boxes in the first two rows of the grid.

Depending on the thermodynamic method set which has been selected,one or more parameters characterize the interaction between the twocomponents. When theBinary Interaction Parameterswindow isinitially brought up, the box at the top of the window must be checkedin order to enable the grid where individual binary interaction parame-ters are entered. For the NRTL and UNIQUAC methods, there areseveral different forms of the binary interaction equations. For theNRTL method, the 5-Parameter equation is the default form. For theUNIQUAC method, the default is the 4-Parameter form of the equation.For these two methods, a different equation form may be selected foreach component pair from theEquation Formatdrop-down list box, inorder to enter the data in the most convenient form. Depending on theselection in theEquation Formatlist box, the appropriate rows in thegrid become active. For most equation formats, many active parametershave default values of 0.0, except for the SRK-Modified-Panagiotopoulos-Reid, PR-Modified Panagiotopoulos-Reid, Glycol,Sour, GPA Sour Water, and Amine methods, where the default value forparameters cij and cji is 1.0.

Heat of Mixing Data

For the Ideal thermodynamic method, an excess enthalpy method maybe specified on theHeat of Mixingwindow. This window is accessedby clicking the appropriateEnter Data... button beside liquid enthalpyon theThermodynamic Property-Modification Datawindow, checkingthe check box and then clicking on the Enter Data button on theThermodynamic Property-Modification-Liquid Enthalpywindow besidetheHeat of Mixingdata item. Checking the box on theHeat of Mixingwindow activates three radio buttons, and the excess enthalpy calcula-tion method may be selected by choosing the desired radio button. Ifeither of the Redlich-Kister Excess Enthalpy methods are chosen, thenthe Redlich-Kister binary parameters may be entered on theBinaryRedlich-Kister Parameterswindow, which is accessed by clicking the

Binary Data... button. When entering the Redlich-Kister binaryparameters for any component pair, the Aij field is required and the otherparameters have default values of 0.0.

User-added Thermodynamic DataTo select a user-added thermodynamic method, select one of the fifteenuser-added methods from the drop-down list box in thePrimaryMethodfield on theThermodynamic Datawindow. TheUser-addedParameterswindow allows the input of parameters for user-addedthermodynamic subroutines. For each row of the grid, the parameter


number (from 1 to 2600) is entered in the first column and theparameter value is entered in the second column.

Note: The User-added Subroutines supplement (an add-on to the stan-dard PRO/II package) is required for user-added thermodynamic meth-ods. Contact your local SIMSCI office for more information.

Defining Transport PropertiesTransport property methods are selected in theThermodynamics -Transport Propertieswindow which is accessed by clicking the

Transport Properties... button on theThermodynamic System -Modificationwindow. Transport properties, i.e., viscosities, thermalconductivities, liquid surface tension, and liquid diffusivities may beselected on a global basis via radio buttons as: specify individually,pure-component averages, petroleum based correlations, the TRAPPmethod, or user-added methods. Note that the TRAPP method does notpredict liquid surface tension and the petroleum method is used topredict this property when TRAPP is selected.

Drop-down list boxes may be used to replace any of the globalmethods, with these options for the properties:

Vapor viscosities: None, pure-component average, petroleum correla-tions, TRAPP method, user-added.

Liquid viscosities: None, pure-component average, petroleum correla-tions, TRAPP method, API method, SIMSCI method, Woeflin methoduser-added.

Vapor and liquid thermal conductivities: None, pure-component average,petroleum correlations, TRAPP method, user-added.

Liquid surface tension: None, pure-component average, petroleum corre-lations, user-added.

Note: The None option for the methods above is available only if theSpecify Individually option is selected for the Transport System.

Liquid diffusivity: None, Wilke-Chang.

Note: A user-added method is not allowed for liquid diffusivitycalculations.


To select a user-added transport method, choose theUser-addedSubroutineoption on theTransport Propertieswindow and select oneof the five methods from the drop-down list.

Note: The User-Added Subroutines supplement (an add-on to thestandard PRO/II package) is required for user-added transport meth-ods. Contact your local SIMSCI office for more information.

The PRO/II online help text provides additional information about thevarious transport property methods. More information may also befound in thePRO/II Reference Manual.

Specifying Water Decant OptionsWhen a method set which supports two-liquid phase calculations isselected via theThermodynamic Datawindow, theThermodynamics -Liquid-Liquid Optionswindow appears. Radio buttons on this windowmay be used to specify that a single liquid phase only be used in the calcu-lations (the default)or that two-liquid phase calculations be performed.

For method sets that support water decant, the user may optionallyselect to decant water as a pure phase. The methods used for the decantwater calculations are selected via radio buttons in theWater Optionswindow which is reached by clicking theWater Options... button ontheThermodynamic System-Modificationwindow. The followingoptions are available:

Calculation of Water Solubility in Nonaqueous Phase: SIMSCI Method (thedefault), Kerosene correlation, Compute from Equation of State (SRKand PR methods only).

Calculation of Decanted Water Properties: Vapor-Liquid Saturation Values,Steam Tables.

Optionally, the user may also check a check box to useGPSA DataBookvalues for calculating the water partial pressure.

More details on decant of free water are given in the online help textand in thePRO/II Reference Manual.


Table 8-1: Predefined Thermodynamic Method Sets

Most Commonly Used:Primary Method (K-value)

VaporEnthalpy

LiquidEnthalpy

VaporEntropy

LiquidEntropy

VaporDensity

LiquidDensity

VaporFugacity

Soave-Redlich-Kwong (SRK) SRK SRK SRK SRK SRK API NONE

Peng-Robinson (PR) PR PR PR PR PR API NONE

Grayson-Streed (GS) CP CP CP CP SRK API NONE

Braun-K10 (BK10) JG JG CP CP IDEAL API NONE

NRTL (NRTL) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL

UNIQUAC (UNIQUAC) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL

UNIFAC (UNIFAC) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL

Note: CP= Curl-Pitzer method, JG = Johnson-Grayson method, API= API Method

Equations of State:Primary Method (K-value)

VaporEnthalpy

LiquidEnthalpy

VaporEntropy

LiquidEntropy

VaporDensity

LiquidDensity

VaporFugacity

BWRS (BWRS) BWRS BWRS BWRS BWRS BWRS BWRS NONE

Peng-Robinson (PR) PR PR PR PR PR API NONE

PR-Huron-Vidal (PRH) PRH PRH PRH PRH PRH API NONE

PR-Panagiotopoulos-Reid (PRP) PRP PRP PRP PRP PRP API NONE

PR-Modified-Panag.-Reid (PRM) PRM PRM PRM PRM PRM API NONE

Soave-Redlich-Kwong (SRK) SRK SRK SRK SRK SRK API NONE

SRK-Kabadi-Danner (SRKKD) SRKKD SRKKD SRKKD SRKKD SRKKD API NONE

SRK-Huron-Vidal (SRKH) SRKH SRKH SRKH SRKH SRKH API NONE

SRK-Panagiotopoulos-Reid (SRKP) SRKP SRKP SRKP SRKP SRKP API NONE

SRK-Modified-Panag.-Reid (SRKM) SRKM SRKM SRKM SRKM SRKM API NONE

SRK-SIMSCI (SRKS) SRKS SRKS SRKS SRKS SRKS API NONE

SRK-Hexamer (HEXA) HEXA HEXA HEXA HEXA HEXA API NONE

Lee-Kesler-Plöcker LKP LKP LKP LKP LKP API NONE

Uniwaals (UNIW) UNIW UNIW UNIW UNIW UNIW UNIW NONE

Generalized Correlations:Primary Method (K-value)

VaporEnthalpy

LiquidEnthalpy

VaporEntropy

LiquidEntropy

VaporDensity

LiquidDensity

VaporFugacity

Braun-K10 (BK10) JG JG CP CP IDEAL API NONE

Chao-Seader (CS) CP CP CP CP SRK API NONE

Chao-Seader-Erbar (CSE) CP CP CP CP SRK API NONE


Table 8-1: Predefined Thermodynamic Method Sets

Grayson-Streed (GS) CP CP CP CP SRK API NONE

Grayson-Streed-Erbar (GSE) CP CP CP CP SRK API NONE

Improved-Grayson-Streed (IGS) CP CP CP CP SRK API NONE

Ideal (IDEAL) IDEAL IDEAL NONE NONE IDEAL IDEAL NONE

Special Packages:Primary Method (K-value)

VaporEnthalpy

LiquidEnthalpy

VaporEntropy

LiquidEntropy

VaporDensity

LiquidDensity

VaporFugacity

Alcohol (NRTL) SRKM IDEAL SRKM SRKM SRKM IDEAL IDEAL

Amine (AMINE) SRKM AMINE SRKM SRKM SRKM IDEAL NONE

Glycol (GLYCOL) SRKM SRKM SRKM SRKM SRKM API NONE

Sour Water (SOUR) SRKM IDEAL SRKM SRKM SRKM IDEAL NONE

GPA Sour Water (GPSWAT) SRKM IDEAL SRKM SRKM SRKM IDEAL NONE

Liquid Activity:Primary Method (K-value)

VaporEnthalpy

LiquidEnthalpy

VaporEntropy

LiquidEntropy

VaporDensity

LiquidDensity

VaporFugacity

NRTL (NRTL) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL

UNIQUAC (UNIQUAC) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL

UNIFAC (UNIFAC) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL

Wilson (WILSON) IDEAL IDEAL NONE NONE IDEAL IDEAL NONE

van Laar (VANLAAR) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL

Margules (MARGULES) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL

Regular Solution (REGULAR) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL

Flory-Huggins (FLORY) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL

UNIFAC TDep-1 (UNIFAC TDep-1) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL



UNIFAC Free Volume (UNIFAC Free Volume) IDEAL IDEAL NONE NONE IDEAL IDEAL IDEAL

Ideal (IDEAL) IDEAL IDEAL NONE NONE IDEAL IDEAL NONE


Stream DataGeneral InformationThis section of data is used to specify the thermal conditions and composi-tions for all feed streams in the flowsheet. It may also be used to furnishinitial estimates of the composition and thermal conditions for recycle tearstreams to enhance recycle convergence. Supplied data for tear streams orany other streams which are products from unit operations are used asestimates only and always replaced by the next calculated set of values.Finally, Referencestreams may be defined to eliminate thermal recycles.

Compositional streams may be of two types: composition fully definedin terms of defined components, or pseudocomponents to be generatedfrom petroleum assay data. Reference streams are always assigned thecomposition of the parent stream.

Compositions may be defined on a mole, weight, standard liquidvolume or vapor volume basis, corresponding to typical laboratory data.It is necessary to provide both a laboratory distillation and streamaverage gravity for petroleum assay streams. Light ends analyses,gravity curves, and molecular weight curves may optionally befurnished to improve the characterization of petroleum assay streams.

The stream thermal conditions may be specified in a variety of waysincluding: defined temperature and pressure, bubble or dew pointconditions, or fraction liquid. For reference streams, only the tempera-ture and pressure may be defined.

Entering Stream DataYou can enter data for a stream on the flowsheet. The data entrywindow that appears contains any data you previously entered (as wellas default values) for the selected stream.

To enter data for a stream:➤ Double-click on the stream or right-click on the unit icon and select

Data Entry..., or select the stream and chooseInput/Data Entry...from the menu bar.

➤ Select the desired stream operation.

The stream name automatically assigned by the program is displayed in theupper left hand corner of this window and may be edited as desired. If thestream is an intermediate or product stream, a check box appears on thiswindow so that an initial estimate may be supplied for the stream.

➤ Select theStream Type.


Figure 8-1: Stream Data Entry Window - Feed Stream

Specifying Composition Defined StreamsWithin the Stream Datamain data entry window:➤ Select theComposition Definedradio button.

➤ Click the Flowrate and Composition button to access theFlowrateand Compositionwindow.

Radio buttons are used to select the stream flowrate basis as:TotalFluid Rate, or Individual Component Flowrates. A data entry boxadjacent to the Total Fluid Rate button is used to enter the total streamflow in mole, mass, standard liquid volume, or standard vapor volumeunits.

The stream composition is supplied in a drop-down list box, and maybe supplied on a mole, mass, standard liquid volume, or standard vaporbasis. Components not defined are assigned zero flowrates. If the totalfluid rate was not given, the flowrate for the stream is taken as the sumof the stream composition. PRO/II displays a running total for thecomposition as it is entered.

When the total fluid rate is supplied and the composition does not sumto that rate or a rate of 100.00± 1.0 or 1.00 ± 0.01 (indicating composi-tion percentage or fraction) an error is signaled. Optionally, a check boxis provided to normalize the composition based on the specified totalfluid rate, in which case no error is signaled for the above condition.


Specifying Stream Thermal ConditionThe thermal condition for all supplied streamsexceptreference streamsmust be specified on theStream Datamain data entry window. Twospecifications must be supplied. The first specification is selected asTemperatureor Pressurevia theFirst Specificationdrop-down list boxand the value entered in an adjacent data entry field.

The second is chosen from theSecond Specificationdrop-down list boxas: Pressure, Bubble Point, Dew Point, Liquid Mole Fraction, LiquidWeight Fraction, or Liquid Volume Fraction. The pressure and theliquid fraction specifications have an adjacent data entry field. Thus,the thermal condition may be:

● Defined temperature and pressure.

● Bubble or dew point (pressure defined, temperature calculated).

● Bubble or dew point (temperature defined, pressure calculated).

● Liquid fraction (pressure defined, temperature calculated).

● Liquid fraction (temperature defined, pressure calculated).

The temperature and pressure may optionally be specified for areference stream. If not specified, the thermal conditions for the parentstream are used.

Specifying Petroleum Assay StreamsWithin the Stream Datamain data entry window:➤ Select thePetroleum Assayradio button.

➤ Click the Flowrate and Array button to enter theFlowrate and Assaywindow.

The flowrate for the assay stream is entered in the data entry fieldprovided as weight or liquid volume units. The cutpoint set for theblend may be selected by clicking the hypertext string default set ofTBP cutpointsto retrieve a list of the problem cutpoint sets. The pseu-docomponent blending option is selected by clicking the text stringincluded in. This option is the default and includes the pseudocompo-nents generated for the stream in the assay blending for the cutpoint set.The excluded fromoption is used when the assay stream is a recycleestimate and the effect of its estimated pseudocomponents on the assayblend properties is not wanted. Entry of the various assay data isdiscussed below. More information on the various laboratory tests isgiven in the PRO/II help text and thePRO/II Reference Manual.


Laboratory Distillation➤ Click the Define/Edit Assay... button on thePetroleum Assay

Streamwindow to enter theAssay Definitionwindow. This win-dow is used to enter the laboratory assay data for the petroleumstream.

➤ Select the type of distillation via radio buttons as: True BoilingPoint (TBP), ASTM D86, ASTM D1160, or ASTM D2887.

The basis for the distillation may be chosen as: Liquid Volume orWeight. Liquid Volume is the default for all distillations except theASTM D2887 which is defaulted as weight. Note that gravity andmolecular weight curves must be on the same basis, volume or weight,as the distillation curve. The distillation data for TBP, ASTM D86, andASTM D1160 are assumed to be at a pressure basis of 14.696 psia. Ifnot, enter the laboratory pressure in the data field provided. For ASTMD86 distillations, aCorrect for Crackingcheck box is provided forapplication of theAPI Data Bookcracking correction to the distillationtemperatures.

The distillation data are entered in the table provided. At least twopoints are required when the cubic spline fitting method is used. Whenonly two points are given, PRO/II uses a probability density function tofill in the curve. For the quadratic fitting option, at least three pointsmust be given for TBP’s and five points for other types of distillations.PRO/II needs the entire distillation curve from zero percent to onehundred percent and extrapolates and interpolates as necessary. Wiseengineers perform their own extrapolations outside of PRO/II, usingtheir knowledge of the stream being characterized.

Gravity Data

The type of gravity data is denoted by radio buttons on theAssayDefinition window as: API Gravity, Specific Gravity, or WatsonK-Factor. The stream average value must be supplied in the data entrywindow provided. Optionally, a gravity curve for the stream may begiven by clicking the Gravity Curve... button on this window to accesstheAssay Gravity Curvewindow which provides a convenient tabularform for entry of the gravity curve.

Molecular Weight Data

A molecular weight curve may be optionally given by clicking theMolecular Weight... button on theAssay Definitionwindow to access

theAssay Molecular Weight Datawindow.This window provides atabular form for entry of the molecular weight curve. Optionally, the streamaverage value may also be supplied in this window.


Lightends Data

Lightends data may be optionally provided by clicking theLightends... button on theAssay Definitionwindow to access the

Assay Lightends Datawindow. The lightends composition may beentered on a mole, mass, standard liquid volume, or standard vaporvolume basis. Any library component or petroleum component that wasdefined as aPETROcomponent may be designated as a lightend.

Several choices are available for specification of the total lightendsflow. These choices are selected via radio buttons and are:

Match to TBP Curve: The lightends rate is determined such that the normalboiling point for the mid percent of the highest boiling lightend exactlymatches the TBP curve. The lightend components are kept in the sameproportions as the supplied composition (the default).

Fraction of Assay: The lightends rate is a specified fraction of the totalstream rate. A basis of liquid volume or weight may also be selected intheBasisdrop-down list box. If no basis is selected, the basis for thedistillation curve is assumed. When this option is chosen and thelightends composition does not add to the specified fraction or to 100.0± 1.0 or 1.00 ± 0.01 (indicating composition percentage or compositionfraction) an error is signaled.

Percent of Assay: The lightends rate is a specified percent of the totalstream rate. A basis of liquid volume or weight may also be selected intheBasisdrop-down list box. If no basis is selected, the basis for thedistillation curve is assumed. When this option is chosen and thelightends composition does not add to the specified percent or to 100.0± 1.0 or 1.00 ± 0.01 (indicating composition percentage or compositionfraction) an error is signaled.

Use Compositions as Actual Rates: The supplied composition is assumed tobe component flows, not fractional composition or percentage composi-tion.

Lightends Rate: The lightends rate is supplied directly in the data entry fieldprovided. When this option is chosen and the lightends composition doesnot add to 100.0 ± 1.0 or 1.00 ± 0.01 (indicating composition percentageor composition fraction) an error is signaled.

Optionally, a check box is provided to normalize the composition basedon the specified total lightends rate, in which case no error is signaledfor a composition total which does not equal fraction, percent or a suppliedrate and does not add to100.0 ± 1.0 or 1.00 ± 0.01.


Stream Thermal ConditionsThe thermal conditions for petroleum assay streams are specified in thesame fashion as that already discussed for compositionally definedstreams.

Specifying Recycle StreamsThe PRO/II calculation engine recognizes recycle loops and automati-cally sets up loop calculations as needed. For many problems, thedefault techniques are satisfactory. For complicated flowsheets withnested recycle loops, the user may prefer to define the loop calculationdetails. Acceleration techniques can also be applied to speed closure ofthe recycle tear streams.

Setting Recycle Convergence Options

Recycle convergence options are entered in theProblem RecycleConvergence and Acceleration Optionswindow which may be reachedfrom the PFD main window by clicking the Recycle Convergence iconon the toolbar.

The followingRecycle Convergence Optionscan be selected with radiobuttons:

Converge all Streams: Convergence is not attained untilall flowsheetstreams are converged within the recycle tolerances. This is the default.

Converge only Tear Streams: Convergence is reached whenall tear streamsare converged. This is the option used by theSIMSCI PROCESSSimulation Program.

Global recycle tolerances may be set in this window. These tolerancesare used for all loops except user specified loops in which tolerancesare supplied. Tolerances may be specified as relative or absolute viadrop-down list boxes. Tolerances are:

Component: Permissible change in a stream component rate from oneiteration to another. The default is 0.01 on a relative basis.

Temperature: Allowable change in a stream temperature from oneiteration to another. The default is +1.0°F or equivalent.

Pressure: Allowable change in a stream pressure from one iteration toanother. The default is 0.01 on a relative basis.

The smallest stream component mole fraction to test for convergencemay be changed from the default value of 0.01 by clicking on thelinked text numeric value. Note that for some problems such as amineplants, this threshold must be lowered to test the residual acid gascomponents in the recycle amine solution.


Frequency of intermediate printed results for recycle calculations maybe selected by clicking the underlined value in the print statement:Print recycle stream composition every 0recycle iterations.

The number of recycle trials to allow before non-convergence issignaled may be entered by clicking the underlined value in the trialsstatement:Set default maximum number of trials for each recycle loopto 20. Note that this is a global value which may be superseded for auser specified loop.

Acceleration options are chosen via radio buttons:

Direct Substitution (No Acceleration): This is the default.

Apply Wegstein Acceleration: Use the Wegstein acceleration method. Thefollowing additional options may be chosen with Wegstein by clickingunderlined default values: first iteration to accelerate (default is 2),iteration interval for acceleration (default is 1), Wegstein lower andupper factors (defaults are -5.00 and 0.00)

Apply Broyden Acceleration: Use the Broyden acceleration method. Whenthis option is selected, the first iteration to accelerate may also besupplied by clicking the underlined (linked text) default value of 2.

Ordinarily, all recycle tear streams are accelerated. Click theAccelerated Tear Streams... button to access theAccelerated Tear

Streamswindow. This window has two options available:

Accelerate All Tear Streams: This is the default.

Accelerate User-specified Tear Streams: When this option is selected, tearstreams are selected in a drop-down list box and moved to theAcceler-ated Streamslist box. Acceleration is only applied to these tear streamsin theAccelerated Streamslist box.

User-specified Recycle LoopsTo select user-specified recycle loops, the user must first select theAlternateor Explicitly Defined by Usercalculation sequence methodsin theProblem Calculation Sequencewindow.

➤ Click the User-specified Recycle Loops button on theProblemRecycle Convergence and Acceleration Optionswindow to reachtheUser-specified Recycle Loopswindow.

➤ Then, click on the check box besideUser-specified Recycle Loops.


A tabular form is used to supply recycle loop information. Each line inthe table has drop-down list boxes which are used to select theStartingUnit and theEnding Unitfor each loop. The adjacentEnter Data...button is clicked to enter additional recycle information via the Indi-vidual Recycle Loop Data window.

Information which may be entered in this window includes:

Number of Trials: Number of iteration trials before non-convergence issignaled. If not supplied, the global value is used.

Recycle Stream Convergence Tolerances: Tolerances may be supplied for theComponent, Temperature, andPressurechanges. A thresholdcomponent level may be supplied by clicking the underlined (linkedtext) default. Note that the global defaults are used when values are notsupplied in this window.

Acceleration Options: TheDirect Substitution, Wegstein Acceleration, orBroyden Accelerationmethods may be selected for acceleration of the tearstream. The following additional options may be chosen with Wegstein byclicking highlighted default values: first iteration to accelerate (default is2), iteration interval for acceleration (default is 1), Wegstein lower andupper factors (defaults are -5.00 and 0.00). For Broyden, the firstiteration to accelerate may also be supplied by clicking the highlighteddefault value of 2.

Scaling Product StreamsGeneral InformationScaling provides an easy way to ratio all of the results in a simulationsuch that the flow of one of the products is equal to a specified flow.For example, it may be desired to build a plant which produces aspecified quantity of product, but the exact quantity of feed required isnot known. Instead of making multiple runs with different feed rates,one run may be made and the complete result scaled, including the feedrate such that the desired product rate is achieved.

To use the scaling feature:➤ Select the menu optionOutputfrom the menu bar of the PRO/II

main window.

➤ Select theReport Formatitem from theOutputmenu.

➤ SelectMiscellaneous Datafrom theReport Formatmenu to accesstheMiscellaneous Report Optionswindow.

➤ Click the Product Stream Scaling button to display theProductStream Scalingwindow.


➤ Click the check box besideScale Stream Flowrate.

➤ Then pick the stream to be scaled in theStream Namedrop-downlist box in theProduct Stream Scalingwindow and select thestream components on which the scaling rate is based with the ra-dio button provided. The default isAll Components. If a Range ofComponentsis selected, the starting and ending components arechosen in drop-down list boxes and the scaling rate is applied to thetotal of all components in this range.

The rate for the scaled product stream, either the total stream or a specifiedrange of components, is supplied in the data entry field provided. The Unitsof Measure feature may be used to supply the scaling rate as moles, mass,standard liquid volume units, or standard vapor volume units.

Non-scaleable Unit OperationsSome unit operation results are not scaleable, that is, the calculated results aredependent on the absolute flow through the unit. For example the calculatedpressure drop through a pipe of specified diameter depends on the flow throughthe pipe and may not be directly scaled for other flowrates. PRO/II disables thescaling option when unit operations are present which are non-scalable. Thefollowing unit operations are non-scalable:

Column Hydraulics, Rigorous Heat Transfer, Pipe, Depressuring,Plug Flow Reactor.

Specifying Reference StreamsA reference stream is a stream of identical composition to its parentstream. When the composition of the parent stream changes, thecomposition of the reference stream is immediately updated to be thesame as the parent stream. This concept is very useful in eliminatingthermal recycles in flowsheets.

Reference streams are designated by double-clicking the stream on thePFD to retrieve theStream Datamain data entry window, selecting theradio buttonReferenced to Stream,and choosing the parent stream inthe drop-down list box. Optionally, a rate may be supplied for thereference stream. If not supplied, the rate of the parent stream isassumed.

Optionally, a temperature and pressure may be specified for thereference stream. If not specified, the thermal conditions of the parentstream are used.


Copying Stream DataPRO/II allows you to copy the thermal and composition data for aselected stream. Process data for a selected stream can be copied to anew flowsheet stream or can be used to replace (overwrite) thecurrently existing data in another selected stream.

Creating a New Stream from an Existing StreamIn the PRO/II main window:➤ Select the desired stream to copy by clicking on the stream label

with the mouse.

➤ ChooseCopyon theEdit menu.

➤ Click the left mouse button on an unoccupied area of the PFD mainwindow or chooseSelect Noneon theEdit Menu to deselect the se-lected stream.

The data for the selected stream can now be copied to a new stream asfollows:

➤ ChoosePasteon theEdit Menu.

The cursor will change to an arrow with a small “s” visible to indicatethat the PFD is now in stream mode.

➤ Create a new stream by clicking the left mouse button on an unoc-cupied area of the PFD main window or on one of the available exitports for a unit icon.

➤ Drag the mouse to the desired unoccupied area of the PFD or feedport of another unit.

➤ Release the mouse button to complete the creation of the stream.

Create additional duplicate streams if desired, or

➤ Click the right mouse button or press <Esc> to exit stream mode.

The newly created stream(s) will have the same thermal conditions,composition, and description as the original source stream.

Copying Data From One Existing Stream to Another Existing StreamIn the PFD main window:➤ Select the desired stream to copy by clicking on the stream label

with the left mouse button.


➤ Click the left mouse button on an unoccupied area of the PFD mainwindow or chooseSelect Noneon theEdit menu to deselect theselected stream.


The data for the selected stream can now be copied to one or moreexisting streams as follows:

➤ Select the desired destination stream(s) with the left mouse button.

➤ ChoosePasteon theEdit menu.

The data from the original source stream will be copied to the destina-tion stream(s), overriding any existing.

For compositionally-defined streams containing calculated data, PRO/IIallows the user to copy the calculated data (temperature, pressure, andone of total composition, liquid composition, or vapor composition)into the designated stream(s).

➤ Select the desired compositionally-defined stream to copy by click-ing on the stream.


➤ Select the desired destination stream(s) with the left mouse button.

➤ ChoosePaste Specialon theEdit menu.

You may chose to paste only the input data of the selected stream orpaste the input data and calculated data (using the total composition, orvapor composition, or liquid composition).

Note: For assay or reference streams, the Paste Special option is notallowed.

Copying Input Stream Data Across Simulation DatabasesTheStream Data Linkfeature described previously will only transfercalculateddata from the source stream to theinput data slots of thedestination stream. To copy input stream data from one simulationdatabase to another, you must use the Windows Clipboard.

To transfer input stream data from one database to another:➤ Select theFile/Openmenu option to open the first database.

➤ Highlight the stream of interest and copy the input data of thisstream to the Windows clipboard by using theEdit/Copymenuoption.

➤ Open up the second database using theFile/Openmenu option.

➤ Paste the clipboard data into the destination stream using theEdit/Paste Specialmenu option.


Linking Stream Data Across Simulation DatabasesTheStream Data Linkfeature allows for the transfer of calculatedstream data across PRO/II simulation databases. By using this feature,you can copy calculated stream data from a source database to the inputdata of a destination database. When modeling a large flowsheet, thispractical feature enables you to:

● Quickly make use of stream data previously calculated in anupstream section of the plant

● Avoid possible simulation errors due to manual re-entry ofstream data

● Easily model each section of the flowsheet as a separate simu-lation, with each section connected by a stream data link.

To define a Stream Data Link:➤ Highlight the stream to be linked to a previous database by clicking

on it.

➤ Select theDefine Stream Data Linkoption from theInput menu.

This brings up theDefine Stream Data Linkwindow as shown in Figure7-15. In this window you must select both the name of thepreviously-run database file, and the stream from that simulation to belinked to your current simulation.

➤ Click on theDefine Linkcheck box.

➤ Enter the name of the previously-run database file, or click on theBrowse button to select from a list of available database files.

➤ Enter the name of the stream from the previously-run database tobe linked to the stream in your current simulation, or click on theBrowse button to select from a list of available streams.

➤ Click the Assay Characterization icon to return to the main PFD.

Note: You can link a stream in the current flowsheet to another streamin the same flowsheet. This includes linking the input of the currentlyselected stream to the calculated output data for that stream.


Updating Stream Data LinksYou may update a stream data link while defining that link, or you mayupdate all defined links at a later time via theInput menu.

To update a Stream Data Link while defining that link:➤ Check theUpdate Nowcheck box in the Define Stream Data Link

window.

➤ Click the Modify button.

To update all defined Stream Data Links:➤ Select theUpdate Stream Data Linksmenu option from theInput

menu.

Note: If the components are different in the two simulation databases,some component rate information may be discarded during the datatransfer. If the source stream has rate information for a componentwhich is not present in the second database, that rate information willbe ignored. If the source stream contains assay pseudocomponents, nocomponent data will be copied to the target stream unless an identicalassay exists in the current (target) simulation.

Note: All stream data link information will be lost if you export thesimulation data to a PRO/II keyword file and then re-import the key-word file.

Refinery Inspection and User-defined PropertiesRefinery Inspection PropertiesandUser-defined Special Propertiesareavailable in PRO/II for calculating bulk stream properties. The streamvalues of the properties can be included in the PRO/II output and can beused in performance specifications.

Refinery Inspection Propertiescomprises fifty-three predefined prop-erties, commonly used by refineries for measuring and specifying unitoperation performance. Examples are cetane index, sulfur content,pour point, kinematic viscosity.

User-defined Special Propertiescan be defined for any other propertyfor which component data or assay data can be provided. Possibleexamples include autoignition temperature, color, $/tonne.


Using Refinery Inspection Properties and User-defined SpecialProperties in a FlowsheetRefinery Inspection Properties and User-defined Special Properties areused in the following ways:

Globally Through the Component Properties WindowGlobal property data for each component in the flowsheet are enteredthrough theComponent Propertieswindow. Values entered here areused everywhere in the flowsheet unless overridden through theTher-modynamic Datawindow, as described below.

Through the Stream Data WindowFor streams that are to be defined in terms of assay curves, streamvalues of Refinery Inspection Properties and User-defined SpecialProperties can be entered either as curves or as average values or both.

Through the Thermodynamic Data WindowThe properties that are to be used are specified in theThermodynamicData window. If there is more than one thermodynamic system in theflowsheet, some properties may be specified for use in one system andothers in another.

Component data for each specified property can also be entered foreach thermodynamic system. Any component data entered for a ther-modynamic system will be used in preference to the data providedglobally wherever that thermodynamic system is invoked.

Note: A property is available only if it has been specified for a thermody-namic system through the Thermodynamic Data window and is availableonly in those unit operations where that thermodynamic system is used.

Entering Global Data Through the Component Properties WindowGlobal component data are entered for each component through theComponent Propertieswindow of PRO/II. Values entered here are usedeverywhere in the flowsheet unless overridden through theThermody-namic Datawindow.

Refinery Inspection PropertiesTo enter component refinery inspection property data globally:➤ Click on the Component Properties icon on the toolbar or select the

Input/Component Properties.... TheComponent Propertieswin-dow appears.


➤ Click on the Refinery Inspection Properties button to bring up theComponent Property Selection for Refinery Inspection Propertieswindow.

➤ Select a property from theProperty Namedrop-down list box.

➤ Click the Enter Data... button to enter global values. If the prop-erty is Kinematic Viscosity, theComponent Data Entry for Kine-matic Viscositywindow will open. Otherwise theComponent DataEntry for Refinery Inspection and User-defined Special Propertieswindow will open.

➤ For each component enter either aData value or anIndexvalue.For some properties the index method is not applicable and no in-dex values may be entered. If the property is Kinematic Viscosity,enter values at two temperatures.

The stream property value is calculated from the individual componentvalues using a chosen stream mixing method.

Note: The SIMSCI databank contains Refinery Inspection Propertiesfor some components; these data will be used if no value is entered inthe input. If no data are present for a component, a fill method can bechosen through the Thermodynamic Data window (see below).

User-defined Special PropertiesTo enter component user-defined special property data globally:➤ Click on the Component Properties button on the toolbar or select

Input/Component Properties...from the menu bar. TheComponentPropertieswindow appears.

➤ Click User-defined Special Properties to access theComponentProperty Selection for User-defined Special Propertieswindow.

➤ Enter the name of a new Special Property in theProperty Namedrop-down list box or select a special property from the list.

➤ Click the Enter Data... button to enter global values. TheCompo-nent Data Entry for Refinery Inspection and User-defined SpecialPropertieswindow will open.

➤ For each component enter either aData value or anIndexvalue.

Entering Assay Data through the Stream Data WindowFor streams that are to be defined in terms of assay curves, streamvalues of Refinery Inspection Properties and User-defined SpecialProperties can be entered either as curves or as average values.


Refinery Inspection PropertiesTo enter assay data for refinery inspection properties:

➤ Double-click on the stream on the PFD. TheStream Datawindowappears.

➤ In theStream Datawindow, click the Petroleum Assay radio buttonand then click theFlowrate and Assay button to access theFlowrate and Assaywindow.

➤ In theFlowrate and Assaywindow, click Define/Edit Assay... toaccess theStream Data - Assay Definitionwindow.

➤ In theStream Data - Assay Definitionwindow, first click the ap-propriate distillation method radio button and then click

Refinery Inspection Properties to access theAssay PropertySelection for Refinery Inspection Propertieswindow.

➤ Select a property from theProperty Namedrop-down list box.

➤ Click the Enter Data... button to enter global values. If the Prop-erty is Kinematic Viscosity, theAssay Data Entry for KinematicViscositywindow will open. Otherwise theAssay Data Entry forRefinery Inspection and User-defined Special Propertieswindowwill open.

➤ Enter the property value(s) as either a stream average, curve againstPercent Distilledor both. If the property is Kinematic Viscosity,enter values at two temperatures.

User-defined Special PropertiesTo enter assay data for user-defined special properties:

➤ Double-click on the stream on the PFD. TheStream Datawindowappears.

➤ In theStream Datawindow click Flowrate and Assay to accesstheFlowrate and Assaywindow.

➤ In theFlowrate and Assaywindow click Define/Edit Assay... toaccess theStream Data - Assay Definitionwindow.

➤ In theStream Data - Assay Definitionwindow clickUser-defined Special Properties to access theAssay Property

Selection for User-defined Special Properties.

➤ Enter the name of a new Special Property in theProperty Namedrop-down list box or select a special property from the list.

➤ Click the Enter Data... button to enter global values. TheAssayData Entry for Refinery Inspection and User-defined SpecialPropertieswindow will open.


➤ Enter the property value(s) as either a stream average, curve againstPercent Distilledor both.

Assigning Refinery Inspection Properties and User-defined SpecialProperties to Thermodynamic SystemsThe properties that are to be used in the simulation must be specifiedthrough theThermodynamic Datawindow. If there is more than onethermodynamic system in the flowsheet, some properties may bespecified for use in one system and others in another. A property isavailable only if it has been specified for a thermodynamic system andonly in those unit operations where that thermodynamic system is used.

Component data for each specified property can also be entered foreach thermodynamic system. Any component data entered in a thermo-dynamic system will be used in preference to the component Globaldata wherever that thermodynamic system is invoked.

To assign refinery inspection properties to a ThermodynamicSystem:

➤ Click on the Thermodynamic Data button or selectThermodynamicData...on theInput menu bar item. TheThermodynamic Datawindow appears.

➤ Select the system for which modifications are to be made in theDefined Systemsbox.

➤ Click the Modify... button to access theThermodynamic Data -ModificationWindow.

➤ Click the Refinery Inspection Properties button. TheThermody-namic Method Selection for Refinery Inspection Propertieswindowappears. This window has a table in which properties and associ-ated parameters and data will be entered. To eliminate the need toenter standard sets of properties repeatedly, predefined lists ofproperties have been set up.

➤ To load the table with a predefined list of properties, select fromthePredefined Listslist. SelectingNonein this list removes allproperties from the table.

➤ Select a property from aProperty Namedrop-down list box in thetable. The available options and their default selections, deter-mined by the property selected, are presented. Change these asrequired. The options are:


● Stream Method, which defines the method used to mix thecomponent property values to produce a value for the stream.The available options are:

• Summation: The stream property value is determined bysumming the product of the component property value andthe component fraction. The fraction may be molar, weightor liquid volume and is calculated from the total stream drycomposition except for kinematic viscosity when it is fromthe dryliquid part of the stream. Any Index data suppliedfor the property will be converted to property values beforethe summation using the equation:

Value ReferenceValueIndex

Reference Index= ×

γ

• Index: The stream property index is determined by sum-ming the product of the component property index and thecomponent fraction. The fraction may be molar, weight orliquid volume and is calculated from the total stream drycomposition except for kinematic viscosity when it is fromthe dryliquid part of the stream. Before the summation,any supplied property values will be converted to indexvalues using the equation:

Index Reference IndexValue

ReferenceValue= ×

γ

This equation is then used to convert the stream index valueto the stream property value.

• User-Formula: The stream property value is determinedfrom the equation in a user-added subroutine which islinked into PRO/II. Data values may be entered for eachcomponent and up to 20 real and integer data values mayalso be supplied.

• User-Index: The stream property value is determined by auser-added subroutine which is linked into PRO/II. Thesame data as for the Index method is available to the user-added subroutine.

• SIMSCI: This method is only available for cloud point andkinematic viscosity. It is an index method but uses specificindex equations.

• API: API procedures may be used to calculate flash point,cetane index, mean average boiling point, cubic averageboiling point, molal average boiling point or net heatingvalue. The API method requires no component data.


• Nelson:This is an alternative correlation to calculate flashpoint and no component data are required.

● Stream Basis, which specifies whether the component values willbe mixed using their mole, weight or liquid volume fractions.

● Component Fill, which specifies the action to be taken whencomponent values are missing for petroleum fractions in thestream. The available options are:

• Zero: This option sets the property value to 0.0.

• No fill: This produces warning messages for missing dataand set to 0.0.

• SIMSCI: This option estimates missing data by SIMSCIcorrelations for kinematic viscosity, smoke point, hydrogencontent, carbon content or carbon-hydrogen ratio.

• API: This estimates missing data by API methods for kine-matic viscosity, pour point or refractive index.

• Nelson:This option estimates missing data by Nelsonmethod for smoke point.

● Component Blend, which defines the way in which missingdata are handled when calculating properties from blendedassay streams. The options are:

• Zero: The property value for the cuts in the assay with nodata are set to 0.0.

• Exclude: The property is calculated by blending only thoseassays which have data for this property.

• Missing: For this option, the blended property is notcalculated and is reported as “Missing”.

➤ Click the Data... button to enter data for this property for thisthermodynamic system. If the Stream Method is defined as User-Formula, the User Formula Data Entry window opens. Otherwise,if the property is Kinematic Viscosity, the Kinematic ViscosityData Entry window will open and for other properties the RefineryInspection and User-defined Special Properties Data Entry windowwill open.

➤ In theKinematic Viscosity Data Entrywindow or theRefineryInspection and User-defined Special Properties Data Entrywindow, for each component enter either aData value or anIndexvalue. For each component enter either aData value or anIndexvalue. If anIndexvalue is entered,Reference Index Datamustalso be entered. For some properties the Index method is not appli-cable and neitherIndexvalues norReference Index Datamay beentered. If the property is Kinematic Viscosity, enter values at twotemperatures.


➤ In theUser Formula Data Entrywindow, for each component enter aDatavalue, which will be passed to a linked User-added Subroutine. Upto twenty real and integer values an also be passed to the subroutine. Themeaning of the data are determined by the calculation subroutine.

User-defined Special PropertiesTo assign user-defined special properties to a ThermodynamicSystem:

➤ Click on the Thermodynamic Data icon or selectThermodynamicData...on theInput menu bar item. TheThermodynamic Datawindow appears.

➤ Select the system for which modifications are to be made in theDefined Systemslist box.

➤ Click the Modify... button to access theThermodynamic DataModificationWindow.

➤ Click the User-defined Properties button. TheThermodynamicMethod Selection for User defined Propertieswindow appears.This window has a table in which Properties and associatedparameters and data will be entered.

➤ Enter the name of a new Special Property in theProperty Namedrop-down list box or select a special property from the list.Change the available options and their default selections asrequired. The options are:

● Stream Method, which defines the method used to mix thecomponent property values to produce a value for the stream.

● Stream Basis, which specifies whether the component values willbe mixed using their mole, weight or liquid volume fractions.

● Component Blend, which defines the way in which missingdata are handled when calculating properties from blendedassay streams.

➤ Click the Data... button to enter data for this property for thisthermodynamic system. If theStream Methodis defined asUser-Formula, theUser Formula Data Entrywindow opens. OtherwisetheRefinery Inspection and User-defined Special Properties DataEntry window will open.

➤ In theRefinery Inspection and User-defined Special PropertiesData Entrywindow, for each component enter either aData valueor anIndexvalue. If anIndexvalue is entered,Reference IndexData must also be entered.


➤ In theUser Formula Data Entrywindow, for each component entera Data value, which will be passed to a linked User-added Subrou-tine. Up to twenty real and integer values an also be passed to thesubroutine. The meaning of the data are determined by the calcula-tion subroutine.

Note: If you have assigned Refinery Inspection Properties to aThermodynamic method set, the standard Stream Data Report will in-clude these Refinery Inspection properties.

Printing Refinery Inspection Properties and User-defined SpecialPropertiesRefinery Inspection Properties and User-defined Special Properties canbe included in PRO/II output reports.

➤ SelectReport Formatfrom theOutputmenu. Then select theMiscellaneousData...menu option. TheMiscellaneous Report Optionswindow appears.

➤ In theRefinery Inspection and User-defined Special Propertiesboxcheck one or both of the following options:Include Input Data— for aprintout or data that has been input and/orInput Program Data— for aprintout of data generated by PRO/II.

For output of kinematic viscosity data:

➤ SelectReport Formatfrom theOutputmenu. Then select theStream Properties...menu option. TheStream Property ReportOptionswindow appears.

➤ Enter two temperatures at which the kinematic viscosity results arerequired.


BVLE (Validating Equilibrium Data)Tables and plots of binary equilibrium data for given pairs of components maybe generated in order to ensure that they are valid in the required range ofoperation. Any thermodynamic VLE or VLLE K-value method may be used.

For liquid activity thermodynamic methods (e.g., NRTL or UNIFAC)the following are calculated:

● K-values,

● Liquid activity coefficients,

● Vapor fugacity coefficients,

● Vapor pressures, and

● Poynting correction.

For non-liquid activity methods, such as equations of state orgeneralized correlations, the following are determined:

● K-values,

● Liquid fugacity coefficients, and

● Vapor fugacity coefficients.

The validation is carried out in thePRO/II - Binary VLE/VLLE Datawindow which is opened by selecting the Binary VLE option from theTools menu or by clicking on the BVLE toolbar button. This window isonly available when at least two components and a thermodynamicmethod have been selected.

To generate a BVLE plot or table:➤ Select the Binary VLE option from the Tools menu or click on the

BVLE toolbar button to bring up thePRO/II - Binary VLE/VLLEData window.

➤ Select the required components for the equilibrium calculationsfrom the drop-down lists.

➤ Then, select constant pressure or temperature operation and enterthe value.

➤ Finally, click on the Calculate button to generate plots (bydefault, all available plots will be generated). If Excel is selected onthe Plot Setup option on theOptionsmenu, tabular data are avail-able in the spreadsheet. Otherwise, only the plots are shown.

Note: For complete technical details see the Utilities topic in thePRO/II Reference Manual.


Chapter 9Unit Operations and Utility Modules

This chapter describes how to use unit operation models. Alsodescribed are the use of utility modules such as theCalculator,Controller, Flowsheet Optimizerand similar functionalities.

For ease of reference, both the unit operation models and the utilitymodules are presented together in alphabetical order:

Calculator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1Column, Batch . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-18Column, Distillation . . . . . . . . . . . . . . . . . . . . . . . . . 9-19Column, Liquid-Liquid Extraction . . . . . . . . . . . . . . . . . . . 9-34Column, Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-39Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-42Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-46Crystallizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-48Cyclone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-51Depressurizing Unit . . . . . . . . . . . . . . . . . . . . . . . . . . 9-57Dissolver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-62Expander . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-63Flash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-65Flash with Solids . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-69Flowsheet Optimizer . . . . . . . . . . . . . . . . . . . . . . . . . 9-70Heat Exchanger, LNG . . . . . . . . . . . . . . . . . . . . . . . . . 9-75Heat Exchanger, Rigorous . . . . . . . . . . . . . . . . . . . . . . . 9-77Heat Exchanger, Simple . . . . . . . . . . . . . . . . . . . . . . . . 9-85Heating/Cooling Curves . . . . . . . . . . . . . . . . . . . . . . . . 9-89Mixer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-93Multivariable Controller . . . . . . . . . . . . . . . . . . . . . . . . 9-94Phase Envelope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-97Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-99Procedure Data . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-105Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-113Reaction Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-114Reactor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-118Reactor, Batch . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-128Reactor, Polymer . . . . . . . . . . . . . . . . . . . . . . . . . . 9-104Solids Separator . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-129Splitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-130Stream Calculator . . . . . . . . . . . . . . . . . . . . . . . . . . 9-132SPEC/VARY/DEFINE . . . . . . . . . . . . . . . . . . . . . . . . . 9-135User-Added Operations . . . . . . . . . . . . . . . . . . . . . . . 9-151Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-163Wiped Film Evaporator . . . . . . . . . . . . . . . . . . . . . . . 9-164

PRO/II User's Guide Chapter 9 Unit Operations and Utility Modules9-1

CALCULATORGeneral InformationTheCalculator is a versatile utility module useful for a variety ofpurposes in flowsheet simulation. Parameters may be retrieved fromthe flowsheet and calculations performed using a FORTRAN-likelanguage. Parameters may be returned to the flowsheet for use by otherunit operations. Some uses for theCalculator include:

● Calculating special stream properties

● Simulating special processing units such as reactors

● Determining operating conditions for other unit operations

● Performing design calculations using flowsheet information

● Producing special output values for reports

● Computing utility costs and economic functions

● Calculating target values forControllersor objective functionsfor Flowsheet Optimizers

This is by no means an exhaustive list; the usefulness of this module islimited only by the ingenuity of the user.

All Calculatorshave two main sections:SetupandProcedure. In thesetup section, unit and stream parameters are retrieved from the flowsheet,constants are defined, names are assigned to calculated results, a sequencetable is set up for the streams used for input and output, and the dimensionsfor the various working arrays may be expanded if desired.

TheProceduresection is where all calculations are performed, using a simplelanguage based on FORTRAN 77. The language permits the use of mathe-matical functions, branching and looping, and assignment statementscommonly used in programming. Special intrinsic functions are available forretrieving flowsheet component and stream information. Special subroutinesare provided for storing calculated results directly in flowsheet streams. Calcu-lated results may also be stored in the “Results” array, making them available tothe other unit operations in PRO/II. A special solution “flag” is provided foruse when aCalculatormodels a unit operation.

Calculator SetupStart Setup by clicking theEdit/View Declarations button on theCalculatormain data entry window to open theView Area:

➤ Click the Parameters… button to retrieve flowsheet parametersinto theCalculator. These variables are accessed in theCalculatorprocedure as elements of arrayP. Click theCalculator parameter

Chapter 9 Unit Operations and Utility Modules PRO/II User's Guide9-2

linked text to open theDefinition window where you can specifythe stream or unit flowsheet parameter to be retrieved. The formatfor this window is identical to that used for theDEFINE and is de-scribed in theSPEC/VARY/DEFINEsection of this chapter. Thereyou will also find a list of the unit and stream parameters that maybe retrieved viaDEFINE.

linked text to open theDefinition window where you can specifythe stream or unit flowsheet parameter to be retrieved. The formatfor this window is identical to that used for theDEFINE and is de-scribed in theSPEC/VARY/DEFINEsection of this chapter. Thereyou will also find a list of the unit and stream parameters that maybe retrieved viaDEFINE.

➤ Click the Constants… button to enter the constant values. Thesevariables are accessed in the Calculator procedure as elements ofarrayC. Although you can enter constants directly in the proce-dure, this array provides a means for collecting constants that needto be updated occasionally into a common location.

➤ Click the Results… button to enter names for the Calculator re-sults. These values are accessed in the Calculator procedure as ele-ments of arrayR. These names will be used in the output report.

➤ Click the Stream Sequence… button to define an ordered table offlowsheet streams. There are two functions for this table. First, itprovides a necessary link between the procedure and the flowsheetstreams for information flow. Second, a calculation loop may beperformed in the procedure for a range of streams, using the posi-tions of the streams in the table to control the loop order.

➤ Click the Arrays… button to declare the length of the storage ar-rays used by theCalculator. These arrays include theP, C, R arraysdefined above, and theIS array that is used to hold stream vari-ables. This array is described in theCalculator Procedurediscus-sion. Two additional arrays appear here. In earlier versions of theCalculator, all local variables had to reside in one of these arrays,Vfor real variables andIX for integers. Now that any valid FOR-TRAN variable name can be used, these arrays are no longerneeded. Nonetheless, they are still available so that olderCalcula-tors will work without rewriting.

OnceSetupis complete, click theHide Declarations button to closetheView Area.

Calculator Procedure

Note: ThePROCEDURE section is required and must end with aRE-TURN statement.

The FORTRAN procedure is entered directly into theProcedurefieldon theCalculatormain data entry window. The procedure may bechecked as is it composed by clicking theCheck Procedure button.


The supported features of the language are discussed in the sectionsfollowing.The supported features of the language are discussed in the sectionsfollowing.

Elements of the LanguageEach statement may contain up to 80 characters. The ampersand (&) atthe end of a line denotes continuation of a statement on the followingline. Note than an asterisk (*) is not valid as a continuation marker,since it signifies multiplication.

All lines of code except thePROCEDURE statement may be preceded bya unique numeric label from 1 to 99999 (shown as ‘‘nn’’ in thismanual).

A dollar sign ($) causes all following characters on the remainder of theline to be interpreted as a comment rather than as code. Unlike inFORTRAN, a ‘‘C’’ in column one does not designate a commentstatement.

Predefined VariablesDefinitions of predefined variables, including default dimensions forarrays, appear in the following table. Use aDIMENSION statement in theCalculatorsetup section to reset the number of elements in each array.

ArraysC, P, V, andR store values in floating-point form. ArrayIX storesinteger values. Forms of use include:

An

whereA is any ofC, P, V, R, or B andn is an integer indicating a singleelement of the array.

A(index)

whereA is any ofC, P, V, R, or B and(index) is an expression, such as(IX2 * 5). The parentheses are required. “A(n)” denotes the same elementas “An”.

Instead of, or in addition to, the suppliedV andIX arrays, standardFORTRAN variables may be used. They may be up to 8 characters longand may not duplicate the names of any supplied variables; otherwisethey follow the conventional FORTRAN rules. The introduction of thisfeature in PRO/II 5.0 means that theV andIX arrays need not be used. Ifthis is the case, the arrays can be dimensioned to one word each to savememory.

Array IS normally is used as the index of aDO loop to step through asequence of streams in the order defined on theSEQUENCE statement.


It may serve as the stream index in PRO/II intrinsic functions. The onlyform allowed isISn. IS(index) is never valid.

Predefined Variables

Variable Nameand Form

Default Dimension(for arrays)

Description and Comments

Cn or C(index) 1<=n<=50 Constant values defined in the setup section. Used onlyon the right hand side of assignment statements

Pn or P(index) 1<=n<=50 Flowsheet parameters set by DEFINE statements. Usedonly on the right hand side of assignment statements.

Vn or V(index) 1<=n<=200 A floating-point work array used on either the left orright hand side of assignment statements. These ele-ments are initialized to a large negative value and arenot available outside the calculator.

Rn or R(index) 1<=n<=200 The array of calculator results, used on either side of as-signment statements. This results vector is available toother flowsheet modules external to the Calculator. Theseelements are initialized to a large negative value.

IXn or IX(index) 0<=n<=9 An array of integer values. The form �IX(index) is invalidon a DO statement. It may be used on either side of as-signment statements.

ISn 0<=n<=9 An array of elements used as indices of DO loops for step-ping through a series of streams in the order defined onthe SEQUENCE statement.

ISOLVE This variable indicates whether or not the Calculatorsolved. It is initialized to 0 upon each entry into the cal-culation procedure. The user assigns all subsequentvalues using an assignment statement.

0 The Calculator has not yet executed (default) or hassolved successfully.

1 The Calculator solved.

2 The Calculator did not solve, but continue flow-sheet calculations within a recycle loop.

3 The Calculator did not solve, all calculations stopunconditionally.

4 The Calculator solved; but stop all subsequentflowsheet calculations. This sets the flowsheetsolution flag to �SOLVED�.

MAXC Total number of components in the problem.

MAXS Maximum number of streams in the problem.


FORTRAN StatementsPROCEDURE

This statement marks the start of the FORTRAN-based proceduresection of theCalculator. It is required.

Declaration StatementsREAL rname1, rname2(i), rname3(j,k) ...

INTEGER iname1, iname2(i), iname3(j,k) ...

DIMENSION name1(i), name2(j,k) ...

These statements are used to define local scalars and arrays for use inthe code. Each subscript may be an integer constant, or two integerconstants separated by a colon to specify both the lower and upperarray bounds. When defined by theDIMENSION statement, variablesassume the normal FORTRAN convention that assigns names startingwith I throughN as integers, and all others as real. Name lengths maybe 8 characters long. Variables defined here may be changed in thecode. Variables not defined here are assumed to be real or integeraccording to the first character.

Variable names must not conflict with any reserved words or predefinedvariables (see table entitledPredefined Variables).

Examples:

DIMENSION A(20,20), B(20), X(20)

REAL MASS

INTEGER COUNT, TAB(100)

REAL REVENU(1990:1995), PROFIT(1990:1995),LOSS(1990:1995)

Note: A variable may only appear once in these statements. The follow-ing is valid in standard FORTRAN, but not in a Calculator Procedure:

REAL MOLWT

DIMENSION MOLWT(50)

Both standard FORTRAN and theCalculatoraccept this equivalentform:

REAL MOLWT(50)


Assignment Statementsnn variable =expression

The “expression” is governed by standard FORTRAN conventions. Theoperations on a given statement are executed in the following order:

1. Expressions within parentheses ( )

2. Functions

3. Exponential (**)

4. Multiplications and divisions (*,/)

5. Additions and subtractions (+,-)

With the exception of exponentiation, calculations with the same prece-dence are evaluated from left to right. Multiple exponentiations withoutparentheses to explicitly specify the evaluation order are not permitted.For example, the following is invalid:

BADVAL = A**B**C

Note: The Calculator-supplied arraysC andP may not appear on theleft side of an assignment statement.


FORTRAN Intrinsic FunctionsThe FORTRAN intrinsic functions tabulated below can be used inexpressions:

FORTRAN Intrinsic Functions

Function Description Arguments Type of Result

Number Type

ABSDIMEXPINTLOGLOG10MINMAXMODNINTSQRTSINCOSTANASINACOSATANSINHCOSHTANH

Absolute ValuePositive DifferenceExponential eTruncationNatural LogarithmCommon LogarithmMinimum ValueMaximum ValueRemainderNearest integerSquare RootSine (radians)Cosine (radians)Tangent (radians)Arc Sine (radians)Arc Cosine (rad)Arc Tangent (rad)Hyperbolic SineHyperbolic CosineHyperbolic Tangent

121111>=2>=2211111111111

realrealrealrealrealrealrealrealrealrealrealrealrealrealrealrealrealrealrealreal

realrealrealintegerrealrealrealrealrealintegerrealrealrealrealradianradianrealrealrealreal


PRO/II Intrinsic FunctionsThe following table lists special functions that allow direct retrieval ofstream and component properties. In the table, “cno ” represents aninteger component number which is an integer constant or variable,“sid ” is a stream identifier orISn value. This identifier must appear ontheSEQUENCE statement to be used by a PRO/II intrinsic function.Property values are retrieved in the UOM used for problem input.

PRO/II Intrinsic Functions

Function Description of Property

Pure Component Properties

CMW(cno)CNBP(cno)CSPGR(cno)CTC(cno)CPC(cno)CVC(cno)COMEGA(cno)

Molecular weightNormal boiling temperatureSpecific gravity (60F/60F)Critical temperatureCritical pressureCritical volume, cc/gm-moleAcentric factor

Properties of Components in Streams

SCMF(cno,sid)

SCWF(cno,sid)

SCVF(cno,sid)

SCMR(cno,sid)

SCWR(cno,sid)

SCLVR(cno,sid)

SCGVR(cno,sid)

Molar fraction of component in streamWeight fraction of component in streamStandard liquid volume fractionMolar rate of component in streamWeight rate of component in streamStandard liquid volume rate of componentStandard gas volume rate of component

Stream Properties

SMR(sid)

SWR(sid)

SLVR(sid)

SGVR(sid)

STEMP(sid)

SPRES(sid)

Mole rate of streamWeight rate of streamStandard liquid volume rate of streamStandard gas volume rate of streamStream temperatureStream pressure


Stream Property Storage Subroutinesnn CALL SRXSTR(type, value, sid) A call to SRXSTR stores aCalculatorvector element as a property of stream “sid ”. Values being stored mustbe computed in the dimensional units used for data input. The resultingstream is flashed at the new conditions to determine its thermodynamicstate.

type This entry identifies the stream property to store. Availableoptions are tabulated below.

Stream Properties Stored by SRXSTR

type= Description

SMRSWRSLVRSGVRSTEMPSPRES

mole rate of streamweight rate of streamstandard liquid volume ratestandard gas volume rate of streamstream temperaturestream pressure

value This argument supplies or identifies the value of the propertyto store. It can be a real constant or variable.

sid Thesid entry identifies the stream in which to store the property.It may be any stream identifier listed on theSEQUENCE statement ofthe setup section, or an element of arrayIS in the formIsn. For exam-ple:

CALL SRXSTR(STEMP, R(14), SR4)

stores the value of element14 from arrayR as the temperature of streamSR4.

nn CALL SRVSTR(type, array, sid, i, j) A call to SRVSTR stores a rangeof values representing component stream properties from aCalculatorarray into a stream. The resulting stream is flashed at the new condi-tions to determine its thermodynamic state.

type This entry identifies the component property to store in thestream. Available options are listed in in the following table.

Stream Component Properties Stored by SRVSTR

type= Description

SCMRSCWRSCLVRSCGVR

molar rate of component in streamweight rate of component in streamcomponent standard of liquid volume ratecomponent standard gas volume rate


array The initial element of a realCalculatorarray containing val-ues to store as properties of components in a stream.

sid Thesid entry identifies the stream in which to store the property.It may be any stream identifier listed on theSEQUENCE statement ofthe setup section, or an element of arrayIS in the formISn.

i, j These two entries are component id numbers. They indicate thefirst and last components, respectively, for which the property is stored.For example, the statement

100 CALL SRVSTR( SCWR, V(12), FD1, 2, 5 )stores elements V(12) - V(15) as the weight flow rates of components2 through 5 in streamFD1. StreamFD1 is re-flashed using the new com-position with the previous temperature and pressure.

Calculational Flow Control Statementsnn GOTO mm This is the standard FORTRAN statement thatbranches to labelmm unconditionally. “GO TO” written as two words isalso supported.

nn CONTINUE This statement serves as a branch destination or theend of aDO loop. It performs no calculations.

IF Statementsnn IF (expression) conditional clause This statement allows logical branch-ing during calculations and conforms to standard FORTRAN rules for“ IF” statements. If the parenthetic expression is true, it executes theconditional clause. The conditional clause maynot be one of the fol-lowing:

REAL

INTEGER

DIMENSION

IF

ELSEIF

ELSE

ENDIF

DO

RETURN


The following table lists logical operators allowed in the expression.

Logical Operators in IF Statements

Operator Description

.EQ.

.NE.

.LT.

.GT.

.GE.

.LE.

.AND.

.OR.

.EQV.

.NEQV.

.NOT.

equal tonot equal toless thangreater thangreater than or equal toless than or equal toboth trueeither trueequivalentnot equivalenttrue/false toggle

nn IF (expression) THEN

ELSEIF (expression) THEN

ELSE

ENDIF

These statements conform to standard FORTRANIF-THEN-ELSE state-ments, allowing for structured branching of code. “ELSE IF” and“END IF” written as two words are also accepted. Block “IF” constructsmay be nested.

DO Loopsnn DO mm iname= i, j, k This statement defines the beginning of aDOloop having a range extending through statement label mm. “i” and “j”are initial and final indices respectively. The increment step “k” is op-tional and defaults to 1.

nn DO mm ISn= sid1, sid2 This statement defines the beginning of astreamDO loop having a range extending through statement label mm.ISn is a stream variable, andsid1 andsid2 must be stream ids appearingon theSEQUENCE statement. No incremental step index (comparableto k) is allowed.

OPEN Statementnn OPEN(FILE=fileide, ACCESS=OVERWRITE or APPEND)

The OPEN statement opens a file for CALCULATOR output. For PC,VAX, and UNIX platforms, the default output name is fileid.CAL, wherefileid is the current input file name. A unique filename of up to 12 charac-ters, can be specified, if necessary. It must, however, have a “.CAL”extension. Underscore characters are not allowed (e.g., FILE_01). AnyOPEN statement automatically closes the previously opened file.


WRITE and FORMAT Statementsnn WRITE (*, format) expression, expression, ...

nn FORMAT (item, item, ...)

These statements allow output using full FORTRAN format control.Output will be to the file most recently opened with theOPENstatement. TheWRITE statement list may include constants, variables,expressions, or array names. Specifying an array name causes allelements of the array to be written.

TheWRITE statement refers to aFORMAT statement defining the outputformat. The following standard FORTRAN format items are supported.

Format Items Function

nIw.d Output integer datanFw.d, nEw.dEe, nDw.d, nGw.dEe Output real data‘xxxxx’, nHxxxxx Output character constantsTn, TLn, TRn, nX Tab controlkP Scale factorS, SS, SP Control of sign output/, : Line controln(...) Grouping

OUTPUT Statementnn OUTPUT {R( i : j ), P( i : j ), C( i : j ), V( i : j ), IX( i : j ), IS ( i : j )}

This is a specialOUTPUT statement provided with PRO/II. It outputscalculator-supplied arrays or portions of these arrays to the currentlyopen file. Entries “i” and “j” refer to the first and last elements of thearray to be output. If they are absent, the entire array will be output.

DISPLAY Statementnn DISPLAY {R( i : j ), P ( i : j ), C ( i : j ), V ( i : j ), IX( i : j ), IS( i : j )}

TheDISPLAY statement prints out calculator-supplied array values tothe standard report file during calculations. Entries “i” and “j” aredefined in the same way as the OUTPUT statement.

TRACE Statementnn TRACE option

TRACE statements control printing an historical trace as calculationsproceed to facilitate debugging the code in the procedure. Options are:

ON Prints line number, statement number, and (action taken/newvariable value) as each statement executes.

BRANCH PrintsTRACE information only for branching statementssuch asIF, GOTO or DO.


OFF Turns off all TRACE options.

Examples:

TRACE BRANCH Traces branching only.

TRACE OFF No trace at all.

TRACE ON Traces every statement.

Calculation Termination Statementsnn STOP This statement stops all flowsheet calculations and proceedsdirectly to the output report. The solution flag for the entire flowsheetis set according to the user-defined value ofISOLVE.

nn RETURN TheRETURN statement signals the end of the calculationprocedure of theCalculatorand must appear as the last statement in theprocedure section. Only oneRETURN statement is allowed. The solu-tion flag for theCalculator is set according to the user-defined value ofISOLVE. RETURN always setsTRACE to OFF.

Sample Calculator ProceduresExample 1: Determination of Flash PointUse Nelson’s method to estimate the flash point from D86 distillationcharacterization data. This sample shows how to calculate the flashpoints of streams V1, V2, V3, V4, V5, and V6 using the formula:

P= 0.64 * (D86(10)+D86(ip))/2.0 - 100.0

where the D86 points are in°F. The final results in°C are stored inR(1)throughR(6).

Before entering the procedure FORTRAN code, it is necessary tospecify the streams (V1 through V6) and establish the two pertinentparameters (the D86 10% and IBP temperatures) for each stream:

➤ Open theCalculatormain data entry window by double-clicking ontheCalculator icon on the PFD.

➤ Click on the Edit/View Declarations button to display theViewAreabox. Click on the Parameters buttons to display thePa-rametersdata entry table.

➤ Enter a number in theParameter Numberdata entry field to enablethe Calculator Parameterlinked text. Click on the linked text toopensDefinitionswindow.

➤ Check theSet Up Definition for Calculator Parameter P(1)box toenable the “Calculator Parameter =Parameter” linked text.


➤ Click the Parameter…hypertext to open theParameterwindowwhere you can specify whether the parameter will be aconstant, astream parameteror aunit parameter. TheConstant/Stream/Unitlist box displays a list with the options “Constant,” “Stream” andthe various types of unit operations that have been placed on theflowsheet.

➤ For this sample problem, select theStreamoption and choose V1from theStream Name:drop-down list box. Choosing a streamname enables the Parameter…hypertext.

➤ Click the linked text to open theParameter Selectiondata entrywindow.

➤ For this sample, chooseDistillation Curvefrom the options in theParameterwindow. The center window will now display the avail-able distillation curve options. Select D86 from the distillationcurve options and choose the desired cut point (here, 10%) from theVolume Percent Distillatedrop-down list box.

This completes the parameter specification for the D86(10%) point ofthe first stream, V1. Repeat these steps to define the D86(Initial Point)for the first stream, V1, then define the D86(10%) and D86(InitialPoint) for the remaining five streams.

➤ Enter the following code into theProcedurewindow (at this pointthis window should still be outlined in red).

DIMENSION D8610(6), D86IP(6)

DO 10 I = 1, 6

$

$ COPY PARAMETERS TO LOCAL ARRAYS,

$ CONVERTING TO DEG F

D8610(I) = P(2*I-1) * 1.8 + 32.

D86IP(I) = P(2*I-1) * 1.8 + 32.

$

$ EVALUATE FORMULA

D86AVG = (D8610(I) + D86IP(I)) / 2.

FP = (D86AVG * .64 - 100.

$

$ CONVERT BACK TO DEG C AND STORE

R(I) = (FP - 32.) / 1.8

10 CONTINUE

RETURN

➤ Commit the code by clicking theOK button.


Example 2: Material Balancing with the CalculatorThis sample demonstrates the use of theCalculator to compute thematerial balance of hydrogen (component 2) about a recycle loop. Wewill set the solution flag to indicate “unit not solved” if the hydrogenbalance is not met to within 0.01% based on the overall feeds. Thisspecification forces the recycle to continue iterating, even if the flowingstreams have changed less than the flowsheet stream tolerance. See theISOLVE andISn entries in thePredefined Variablestable on page 9-5 fora listing of solution flags and for an explanation of the use of theISnvariable inSEQUENCE statements.

Before entering the procedure code, we must:

● Establish theStream Sequencefor the recycle loop.

● Provide a label for theResult.

Establishing the Stream Sequence:

The streams pertinent to this example are a hydrogen feed stream(H2FD), two feed streams (FD1, FD2), a purge gas stream (PURG),and vapor and liquid product streams (PRDV, PRDL).

To set up the stream sequence that will be used by theCalculator, carryout the following steps:

➤ Open theCalculatormain data entry window by double-clicking ontheCalculator icon.

➤ Click on the on the Stream Sequence button to display two win-dows, one containing a list ofAvailable Streamsand the other a listof Selected Streams.

➤ Add the streams H2FD, FD1, FD2, PURG, PRDV and PRDL in thegiven order. If you add the streams in the wrong order, you can eas-ily change their sequence by removing the improperly positionedstream from the Selected Streamswindow and reinserting it beforeor after the appropriate stream that you have highlighted in theSe-lected Streamswindow.

Labeling the Result:➤ When you have established the desired stream sequence, click on

the Results button to display theResult NumberandPrint Namedata entry table.

➤ Enter “1” in theResult Numberfield of the first row to enable thePrint Nameentry field. This integer is stored in the first position oftheR() array. For this sample problem, call the result “RelativeMB.”


➤ Enter the following code into theProcedurewindow, which shouldstill be outlined in red at this point:

$ SUM UP H2 IN FEED STREAMS

$ HYDROGEN IS THE SECOND COMPONENT IN THE COMPONENT LIST

$ SCMR(2, n) IS THE MOLAR FLOW RATE IN THE nth STREAM

$

H2FEED = 0.0

DO 10 IS1 = H2FD, FD2

H2FEED = H2FEED + SCMR(2,IS1)

10 CONTINUE

$

$ CHECK IF ANY H2 IN FEED. IF NOT, SET “NOT SOLVED” FLAG.

$

IF (H2FEED .LT. 0.0001) THEN

R(1) = 0

ISOLVE = 2

GO TO 99

ENDIF

$

$ SUM UP H2 IN PRODUCTS

$

H2PROD= 0.0

DO 20 IS1 = PURG, PRDL

H2PROD = H2PROD + SCMR(2, IS1)

20 CONTINUE

$ CALCULATE IMBALANCE

$

R(1) = (H2FEED - H2PROD) / H2FEED

$

$ CHECK IF IN BALANCE. IF SO, RETURN.

$ IF NOT, SET “NOT SOLVED” FLAG.

$

IF(ABS(R(1)).LE.0.001) THEN

ISOLVE =1

ELSE

ISOLVE =2

ENDIF

$

99 RETURN


COLUMN, BATCHGeneral InformationTheBatch Columnunit operation models a wide range of columnoperating scenarios. TheBatch Columnunit may be run in a true batchsimulation mode, with the feedstock charged to the stillpot prior todistillation and products taken from the accumulator at various times,or in a semi-batch mode where feedstock may be introduced duringdistillation and products drawn from the column or accumulator oversome time interval. Batch distillation calculations may also be inte-grated into a steady-state process simulation. The unit configurationautomatically considers the presence of implicit holding tanks forcontinuous flow streams which provide the time-variant feedstock tothe batch unit. Implicit consideration of holding tanks for all productstreams (as drawn from the accumulator at different times, or as drawnfrom the column during distillation) is also made because of the cyclicoperation. A representation of the product continuous flow streamcomes from the amount of product divided by the batch cycle time.

Thermodynamic SystemThe thermodynamic system for theBatch Columnmay be specified forthe unit as a whole or for selected trays.Batch Columnalso allows theuse of electrolyte thermodynamic methods.

Detailed InformationFor detailed information about the use of theBatch Columnunitoperation, consult thePRO/II Add-On Modules User’s Guide.


COLUMN, DISTILLATIONGeneral InformationTheColumnunit operation may be used to simulate any distillation orliquid-liquid extraction process. Liquid-liquid extraction units aredescribed in theLiquid-Liquid Extraction Columnsection of thischapter. A column must contain at least one equilibrium stage or theo-retical tray. For purposes of this discussion, the term “trays” is used todenote “equilibrium stages.” The trays are considered to be linked withthe vapor from each tray entering the next higher tray and the liquidfrom each tray feeding the next lower tray. There is no limit on thenumber of trays in a column model.

The condenser, when present, is always numbered as tray one and thereboiler, when present, is assigned the highest tray number in themodel. Any tray may have a feed, product draw, or duty. The top andbottom trays must have either a feed or a duty.

Distillation columns may simulate vapor/liquid, vapor/liquid/water orvapor/liquid/liquid equilibrium processes.

Feeds and ProductsColumn feeds and products are added during the flowsheet constructionin the PFD main window. Click theColumn Feeds and Products…button on the Column main data entry window to open theColumnFeeds and Productswindow.

Feed tray numbers may be added or changed in this window. There isno limit on the number of feeds a column may have. The feed flashconvention to use for all feeds to the distillation column is selected withradio buttons as:

Vapor and liquid to be on the feed tray: The default.

Flash the feed adiabatically, vapor onto the tray above and liquid onto the feed tray.For this option, the vapor is placed on the feed tray when the feed trayis the bottom tray of the column.

For products, the product type, phase, tray number, and flowrate aresupplied in this window. There is no limit on the number of products adistillation column may have and products may be withdrawn from anytray of the column. Product types include: Overhead, Bottoms, Fixed RateDraw, Total Phase Draw, and Pseudoproduct. Every column must have anoverhead product leaving tray one and a bottoms product leaving thehighest numbered tray. TheSure, Inside-Out (IO)andEnhanced IOalgo-rithms may have a decanted water product from tray one (the condenser).TheSurealgorithm may also have water draws from any tray. For


vapor/liquid/liquid equilibrium (VLLE) processes, either of the liquidphases may be drawn from any tray in the column.

You must supply product rates for all fixed rate draw products in molar,mass, or liquid volume units. You must also provide an estimated valuefor either the overhead or bottoms product. For total draw products, thesupplied rate is always assumed to be an estimate. The estimated valuefor the overhead or bottoms rate should be as accurate as possible toenhance convergence. You must use aPerformance Specificationto seta desired flow for the overhead or bottoms product.

PseudoproductsPseudoproducts are used to create streams corresponding to columninternal streams, making them available for flowsheet calculations.Define pseudoproducts in theColumn Pseudoproductswindow whichyou may reach by clicking thePseudoproducts button on theColumnFeeds and Productswindow. The following types of pseudoproductsare available:

● Net tray liquid or vapor flow

● Total tray liquid or vapor flow

● Pumparound liquid or vapor bypass flow

● Thermosiphon reboiler feeds and products

Thermosiphon reboiler streams are limited to theInside-Outalgorithm.

Column AlgorithmSelect the solution algorithm in the drop-down list box on theColumnmain data entry window. The available algorithms are:Inside-Out(thedefault),Sure, Chemdist, Liquid-Liquid, Enhanced IO,andElectrolytic.Detailed information about the column algorithms is available in theonline help.

Inside-Out: The Inside-Outalgorithm is the preferred option for mostdistillation problems, especially those involving systems of hydrocar-bons, because of its speed and insensitivity to the estimated solutionprofiles.

Sure: TheSurealgorithm should be used for columns where free waterexists on multiple trays.

Chemdist: TheChemdistalgorithm is well suited to highly non-idealsystems and VLLE processes.

Liquid-Liquid TheLiquid-Liquid algorithm is used to model liquid-liquid extraction units described in theLiquid-Liquid ExtractionColumnsection of this chapter.


Enhanced IO: TheEnhanced IOcolumn algorithm extends the capabili-ties of the defaultInside-Outalgorithm.Enhanced IOallows zeroflowrates, water decant off any tray, total draws from trays and pumpa-rounds.

Electrolytic: TheElectrolyticmethod is used to model non-ideal aqueouselectrolytic distillation columns involving ionic species. Refer to thePRO/II Add-On Modules User’s Guidefor detailed information on thiscolumn algorithm.

ReactionsReactions in the column can be modeled by theChemdistor Liquid-Liquid extraction algorithms found in theAlgorithmdrop-down list oftheColumnwindow. Enter pertinent data in theColumn - ReactionSelectionwindow accessible via theReactions… button on theColumnwindow. In theColumn - Reaction Selection windowyou canselect and modify column reactions, specify stage-wise reactingvolumes, designate non-condensible components, select non-volatilecatalysts and specify data for user-added subroutines or kinetic proce-dures. The reactions specified here are limited in scope to the simula-tion of reactive distillation and (reactive) liquid-liquid extraction.

Column - Reaction Selection

To modify reaction sets defined inReaction Data, select theIncludeReactions in Column Calculationscheck-box. All the reactions definedvia Input/Reaction Dataare now available to the column. Reactionscan be selected from a drop-down list underReaction Set from ReactionData,and a local set-name and description can be assigned. Moreover,the individual reactions can be modified by in theReaction Definitionswindow accessible theModify Data button.

The selected reaction sets can also be assigned to individual trays (orranges of trays) by selecting reaction sets from a drop-down list underColumn Reaction Setand then entering a tray range, i.e., starting tray toending tray.

Note: Although you can modify a local copy of a reaction set in the col-umn, the original reaction set specified in the ‘Reaction Data’ sectionremains unchanged.

Reacting Volumes

The user can specify volume available for reaction (effective volume)per stage for both liquid and vapor phase reactions in theColumn -Tray Effective Reaction Volumeswindow accessible from theReaction


Selectionwindow. A tabulation of tray numbers and the respectivevolumes is provided for data entry. This specification is used in calcu-lating the rate of kinetic reaction.

Non-Volatile Catalyst

Components that catalyse a reaction without volatilizing can beselected and the quantity of their charge specified as an amount or afraction in theColumn - Non-Volatile Catalyst for Boiling Potwindowaccessible from theColumn - Reaction Selectionwindow.

Non-Condensibles

Non-condensing components can be specified in theColumn - Non-Condensing Componentswindow accessible from theColumn -Reaction Selectionwindow.

Subroutine/Procedure Data

Data used for user-added subroutines and kinetic procedures can bespecified in the form ofInteger, RealandSupplemental Dataentries intheColumn - User Subroutine and Procedure Datawindow accessiblefrom theColumn - Reaction Selectionwindow via the Subroutine/Procedure Data button. See theReaction DataandProcedure Datasections in this chapter for detailed information on the data require-ments for these utility modules.

Modify Data (Reaction Data)

All data pertaining to a reaction (in a specified reaction set) can bemodified - except for reaction stoichiometry - in theColumn-ReactionDefinitionswindow accessible via theModify Data… button in theColumn-Reaction Selectionwindow. The calculation method for areaction can be modified to follow a user-added subroutine, procedureor kinetic power-law expression. The reaction type can also be changedto Kinetic, Equilibrium or Conversion. All reaction data thatcompletely specify any of the above reaction types (except stoichio-metry) can be changed in the data entry fields accessible via the

Enter Data… button under theAdditional Datacolumn for the respec-tive reaction.

Instructions for entering data for the three types of reactions (Kinetic,Equilibrium andConversion) are covered in detail in theReaction Datasection of this chapter (page 9-114 seqq).

Calculated PhasesSelect the appropriate phase system in the drop-down list box on theColumnmain data entry window. All distillation algorithms supportthe default phase system of vapor/liquid. TheSureandChemdistalgo-


rithms also support the vapor/liquid/liquid system. In addition, theSureandEnhanced IOalgorithms support the phase systemvapor/liquid/water that allows a free water phase on any tray of acolumn.

Number of TraysEnter the number of trays in the model in the data entry field providedon theColumnmain data entry window. Every Column must have atleast two trays. There is no limit on the number of trays in a Column.

Number of IterationsSupply the number of iterations in the data entry field provided on theColumnmain data entry window. The number of iterations correspondsto the number of outerloop trials for theInside-Outalgorithm and thenumber of trial solutions for the other algorithms. A non-convergence isflagged when this number of iterations is performed and the columnequations are not satisfied within the tolerances. The default values are 15for theInside-Outalgorithm, 10 for theSurealgorithm and 20 for theChemdistalgorithm.

Pressure ProfileThe pressure for every tray in a column model must be defined. Allcalculations are performed at the defined tray pressures. Define thetray pressures in theColumn Pressure Profilewindow which you mayreach by clicking thePressure Profile… button on theColumnmaindata entry window. Tray pressures may be supplied on an overall ortray-by-tray mode by choosing a radio button in this window.

For the overall mode, supply the top tray pressure (tray two for columnswith condensers) and either the pressure drop per tray or the total pressuredrop aross the column. A default value of zero is supplied for the pressuredrop per tray and the column pressure drop. All tray pressures are derivedby linear application of the supplied pressure drop.

Individual tray pressures are supplied for the tray by tray mode. Notethat the top and bottom trays must be included when supplying a tableof individual tray pressures. Missing pressures are determined bylinear interpolation of supplied values. This method is useful fordefining the pressure profile for columns with irregular pressureprofiles, such as refinery vacuum units.

CondensersThe condenser is always a heat sink on tray one. It is defined in theColumn Condenserwindow which you may access by clicking the

Condenser… button on theColumnmain data entry window. The top


products from columns with condensers correspond to the productsfrom the reflux accumulator drum. The pressure for all types ofcondensers is supplied in this window.

The condenser type is selected with the appropriate radio button fromthe following options:

Partial: This condenser is an equilibrium stage and may or may nothave a net liquid product as well as vapor product. The net liquidproduct, if present, is defined as a “Fixed rate liquid draw” from trayone. The condenser temperature is the dew point of the equilibriumvapor. An optional estimate for the condenser temperature may besupplied in theColumn Condenser window. The condenser pressure andduty may also be supplied.

Bubble Temperature: The tray two vapor is cooled to a bubble point liquidphase and one portion is returned as reflux to tray two and the otherportion withdrawn as the “Overhead” product from the column. Anoptional estimate for the condenser temperature may be supplied in theColumn Condenserwindow. The condenser pressure and duty may alsobe supplied.

Subcooled, Fixed Temperature: The tray two vapor is cooled below itsbubble point as defined by a subcooled temperature provided in thiswindow. PRO/II ascertains that the product is subcooled, and, if, not,signals a non-convergence condition with an appropriate diagnosticmessage. The subcooled liquid product is designated the “Overhead”product from the column. The condenser pressure and duty may also besupplied.

Subcooled, Fixed Temperature Drop: This condenser is the same as thesubcooled type described above except that the degrees of subcoolingbelow the product bubble point is defined, always resulting in asubcooled “Overhead” product. The duty and pressure for thecondenser may also be supplied in this window if desired.

If the duty is designated as a parameter to vary, any supplied duty forany of these condenser options is used as an estimate.

Column ReboilersColumn reboilers are described in theColumn Reboilerwindow whichis entered via theReboiler button on theColumnmain data entrywindow. The reboiler type is selected with a radio button on this form.The default type is the Kettle (Conventional) reboiler, which corre-sponds to a duty on the bottom tray of the column with the equilibriumliquid withdrawn as the “Bottoms” product.


For theInside-Outalgorithm only, two other reboiler types are available:

● Thermosiphon without Baffles, and

● Thermosiphon with Baffles.

The thermosiphon without baffles type corresponds to the case whentheColumnbottom product and reboiler feed are withdrawn from acommon sump.

Note: Thermosiphon reboilers with baffles in which the reboiler returnflows into the reboiler sump and overflows to the product sump areequvalent to the “no baffles” type for simulation purposes and shouldbe modeled as such.

One specification may be selected for thermosiphon reboilers bychoosing the appropriate radio button and entering a value in the fieldprovided. Choices include:

● Reboiler return liquid fraction

● Return temperature

● Temperature change across the reboiler

● Reboiler circulation rate.

An estimate for the return fluid liquid fraction or circulation rate, as isapplicable, may be given to enhance convergence.

The duty for the reboiler may also be supplied in this data entrywindow if desired. If the duty is designated as a parameter to vary, anysupplied duty is used as an estimate.

Heaters and CoolersSide heaters and side coolers may be supplied via theColumn SideHeaters/Coolerswindow accessible via theHeaters and Coolers…button on theColumnmain data entry window. Side heaters andcoolers that are associated with a pumparound are not entered with thiswindow. A negative duty indicates cooling; a positive duty is used forheating. There are no limits on the number of side heaters/coolers.

For each side heater/cooler, the following information must beprovided: tray number, a reference name, and the duty, with the appro-priate algebraic sign.

Flash ZonesTheFlash Zonecalculation models a fired heater added to a tray in anInside-Outcolumn. Flash zones are associated with column heaterswhen a feed stream entering the column is heated in a separate furnace.


The furnace is considered as an additional theoretical stage. Liquidfrom the tray above the flash zone or vapor from the tray below theflash zone could enter the flash zone or they can bypass it. Data entryfields for flash zones can be accessed through the like-named button ontheHeaterdata entry window. Specification options include fired heaterefficiency, vapor and liquid by-pass fractions and transfer line tempera-ture drop.

Column Heat LeaksColumn heat leaks may be modeled by clicking theHeat Leak buttonon theColumn Side Heaters/Coolerswindow to open theColumn HeatLeakwindow. The heat leak may be designated as:

● Overall, or,

● By Individual Trays

For theOverall option, the heat leak duty for all of the trays except thereboiler and condenser is given on a per tray basis or total columnbasis. A heat leak may also be provided for the condenser and thereboiler, if desired.

For theBy Individual Traysoption, heat leak duties for ranges of traysare supplied as tabular input. At least two values must be supplied.Heat leaks for trays not given, but which lie between trays with definedheat leaks, are determined by linear interpolation.

Pumparounds and Vapor BypassesColumn pumparounds and vapor bypasses may be defined for theInside-Out and Sure algorithms in theColumn Pumparoundswindowwhich is accessed via thePumparounds… button on theColumnmaindata entry window. A pumparound may be either a liquid or vapor, withvapor pumparounds more commonly termed “bypasses.”

Pumparounds are added and edited in a tabular form by clicking onhypertext strings. Entries for each pumparound include: phase, pumpa-round name, draw tray, return tray, return pressure, and two specifica-tions. Supply these specifications in theColumn PumparoundSpecificationswindow which is entered by clicking the two specifica-tionshypertext string.

The following specification combinations are selectable via radio buttons:

Rate and Duty: The rate and duty data entry fields are enabled for input.A reference name may also be supplied for the heater.

Rate without Heater: The rate field only is enabled for input.


Rate and Return Condition: The rate and return condition fields are enabledfor input. The return condition may be the temperature or the tempera-ture drop or the liquid fraction. A reference name may also be suppliedfor the heater.

Duty and Return Condition: The duty and return condition fields areenabled for input. The return condition may be the temperature or thetemperature drop or the liquid fraction. A reference name may also besupplied for the heater.

For theSurealgorithm only, the pumparound rate may be designated asthe total fluid leaving the tray. Total liquid pumparounds must pumpdown the column and total vapor pumparounds (bypasses) must flowup.

Initial EstimatesAll column algorithms use an iterative solution technique, starting froman initial estimate of the tray temperature, flow and compositionprofiles. The initial estimate may be produced internally using aninitial estimate generator and/or provided by the user as initial profiledata. User-supplied profiles may also be used to selectively replacevalues produced by an estimate generator.

Click the Initial Estimates… button on theColumnmain data entrywindow to enter theColumn Initial Estimateswindow. To use an initialestimate generator, select the generator method from the drop-down listbox. Methods provided are:

Simple: Profiles are determined by a simple material balance.Temperatures are determined from estimated product compositions.This model is quick and adequate for simple column configurations.

Conventional: A general method designed to produce an adequateestimate for most distillation problems. Shortcut calculations are usedto estimate the product flows and compositions. The compositions areused to estimate temperatures. Internal flows are estimated by usingthe product flows and a reflux estimate. This method works best forconventional fractionators with condensers and reboilers in whichclassic Fenske techniques provide reasonable results. Special tech-niques are also included for absorbers and strippers.

Refinery: This method is designed for complex refinery columns whichhavebottom steam instead of reboilerssuch as crude and vacuumcolumns, F.C.C. main fractionators, etc. These columns may also haveside columns, pumparound cooling circuits, and decanted water at theoverhead accumulator. A multi-product shortcut technique developedby SIMSCI is used for these columns. The user-supplied estimates for


the product rates are used in the shortcut model. Adjustments in theprofiles are made for side coolers.

Chemical: This generator should be restricted to highly non-idealchemical distillation problems. The method is time consuming anduses successive series of adiabatic flashes up and down the column toestablish the tray compositions.

When using an estimate generator, you may optionally providetemperature estimates for the following trays: condenser, top tray,bottom tray of column, and reboiler. You may also provide an estimatefor the reflux rate or reflux ratio. When no reflux estimate is providedby the user, PRO/II supplies a reflux ratio of 3.0 (which solves manycolumns). Any supplied data replaces values predicted by the estimategenerator.

When an initial estimate generator is not used, the minimum data whichmust be supplied as input profiles are tray temperatures and flows,either vapor, liquid, or a combination thereof. Note that the minimumdata which may be supplied are the temperatures and flows for the topand bottom trays for the column. While these are the minimum datarequired, they are rarely adequate to produce an acceptable initialestimate. It may also be desirable to provide solution profiles from aconverged solution to speed future calculations with a column model.

Initial profiles are entered in tables accessed by clicking the followingbuttons on the Column Initial Estimates window:

● Net Vapor Rates…

● Vapor Composition…

● Liquid Composition…

● Tray Temperatures…

● Net Liquid Rate…

Composition estimates may be helpful for highly non-ideal mixtures;however, they are rarely needed for most problems.

Performance SpecificationsPerformance specifications orSPECsmay be imposed on a columnoperation such that product stream flows or properties, column internalflows, column tray temperatures, etc., are at desired values in thesolution. For eachSPEC, a degree of freedom orVARYmust be calcu-lated. For a column, aVARYmay be a feed stream rate, heat duty, orthe draw rate for a “fixed rate draw.” Furthermore, for convergence tobe achieved, there must be a direct effect on all of theSPECsby thecollective set ofVARYs.


To supplySPECsand defineVARYsfor a column, click the PerformanceSpecifications button on the mainColumndata entry window to accesstheColumn Specifications and Variableswindow. SPECsandVARYsareentered or edited by clicking on the hypertext strings. PRO/II requires thatthere be an equal number ofSPECsandVARYs. Thus, whenever you addor delete aSPEC, you are required to add or delete aVARY.

SPECsandVARYsuse the general form in PRO/II and are discussedmore fully in theSPEC/VARY/DEFINEsection of this chapter. A list ofthe stream and column parameters which may be used forSPECsandVARYsis also given in that section.

Convergence DataConvergence data includeConvergence Parameters, ConvergenceTolerances, Homotopy Options for Convergence SpecificationsandConvergence History(printout options) forColumniterations. Thesedata are entered in theColumn Convergence Datawindow accessiblevia the Convergence Data… button on theColumnmain data entrywindow.

Convergence tuning parametersDamping Factor: A damping factor of less than unity may be used toimprove convergence when the convergence is oscillating. Refinerycomplex fractionators should be given damping factors of 0.8.Chemdistcolumns may require more severe damping. A default valueof 1.0 is supplied by PRO/II. Damping cannot be applied to the Surealgorithm.

Damping Cutoff: The damping factor cut-off value is used for theChemdistalgorithm. The damping factor is only applied when the sumof the errors is larger than this value. A default value of 10-8 issupplied by PRO/II.

Error Increase Factor: This factor limits the increase in the sum of theerrors from iteration to iteration. PRO/II supplies a default value of 1.0for the Inside-Outalgorithm or 100 for theChemdistalgorithm. Thisfactor does not apply to theSurealgorithm.

Component Averaging Factor: This weighting factor for update of composi-tions is used for theSurealgorithm. A factor of 1.0 gives equal weightto the current and last set of compositions; a factor of 2.0 gives doubleweight to the last set of compositions, and so forth. A default value of0.0 is supplied by PRO/II.

Key Component: In rare circumstances, specifying a key component canenhance the convergence for theSurealgorithm. The key component isnormally determined by PRO/II but may be specified by the user.


Stop if no improvement after 5 iterations: The number of consecutiveSurealgorithm iterations allowed without improvement in the solution. Youcan change the number of iterations by clicking on the hypertext string.Changing this parameter rarely, if ever, results in convergence.

Note: The use of tuning factors usually results in an increase in thetime required to solve a distillation problem.

Convergence Tolerances

Tolerances for the column equations may also be changed although thisshould rarely, if ever, be done and never as a means to reach aconverged solution. Tolerances are:

Bubble Point: The maximum bubble point error for each tray. Thedefault is 10-3.

Enthalpy Balance: The maximum heat balance error for each tray. Thedefault is 10-3.

Equilibrium K-value: The maximum allowable relative change in acomponent K-value generated in the outer loop of theInside-Outalgorithm versus the last value used in the inner loop. The default is10-3.

Component Balance: The maximum relative component balance error foreach tray. Not used for theInside-Out algorithm. The default is 10-3.

Homotopy Options for Convergence on Specification

The homotopy option is an aid to converging simulations where thespecification is difficult to meet by virtue of the value of the specifica-tion (as opposed to the type of specification). The homotopy optionwas designed forReactive Distillationwhere convergence is morecomplex, but it may be used for any column algorithm.

One example of the use of homotopy is to systematically increase trayvolumes to very large values to determine the equilibrium compositionsfor reversible kinetic reactions.

The homotopy option allows you to solve the simulation with an initialvalue for the specification and then automatically move to the desiredfinal value in a set number of steps. The column is converged at eachstep.

To use the homotopy option for any specification, you must supply theinitial value of the specification and the number of intervals to use inmoving from the initial value to the final value. you cannot change thefinal value in this window.


The homotopy option may be used for a specification which is variedby aController or Flowsheet Optimizer. If Initially is selected underthe field entitledApply During Control Loop(the default), thehomotopy iterations will be carried out to meet the given column speci-fication. If the specification value is then changed by another unitoperation, the column will solve without homotopy iterations. IfAlwaysis selected, the homotopy iterations will be carried out everytime the column is reconverged after the specification has beenchanged. In this case, the initial value will be the last converged speci-fication value, not the supplied value.

Convergence History

Printout of the column iterations is useful in diagnosis of a convergencefailure. History printout for the iterations may be requested by clickingthe Enter Data… button and selecting the printout level desired.

Tray HydraulicsTray hydraulic calculations may be used to size new columns and torate existing tray or packed columns. To perform sizing or rating calcu-lations, click the Tray Hydraulics… button on theColumnmain dataentry window. For sizing and rating purposes the column is divided intosections of trays or packing on theColumn Tray Hydraulicswindow. Entertray sizing and rating information in theColumn Tray/Packing RatingorColumn Tray/Packing Sizingwindows accessible via theEnter Data…button. The Glitsch valve tray method is used to perform the tray calcu-lations. The valve tray results are derated by five and twenty percentrespectively, to represent the performance of sieve and bubble cap trays.

For packed columns, random or structured packings are available, asare various types of metallic and ceramic rings and saddles.

For sizing calculations, column diameter for each tray is sized inde-pendently to meet the specified or default flooding criteria. The largestdiameter in each section is then selected and the entire section isre-rated using the largest requiredstandarddiameter.

For rating calculations, the percent of flood is calculated for each tray. Thefeature of multiple sections of trays is useful in representing existingcolumns, which often have a variety of tray and downcomer arrangements.

Tray EfficienciesAll trays in a column model are treated as equilibrium stages ortheo-retical traysunless one of the tray efficiency models is used. Thisimplies that the user must apply some type of tray efficiency to theactual number of trays in the column to determine the number of theo-


retical trays to use in the model. Engineers typically use overall trayefficiency factors based on experience to convert actual trays to theo-retical trays. This isalmost alwaysthe best manner in which to modeltray efficiency, since generalized correlations for overall tray efficiencyare non-existent in the literature.

For theInside-Outalgorithm, PRO/II provides several tray efficiencymodels:

● Murphree

● Equilibrium

● Vaporization.

For theChemdistalgorithm, only the Vaporization model may be used.

However,noneof these models predicts the overall tray efficiency. Allof the models use an equation or factor to adjust the equilibrium vaporcomposition leaving a tray. The models are useful for tuning a tray or afew trays in aColumnmodel, but their general application to all trays ina column is not recommended.

To use tray efficiencies, click theTray Efficiencies… button on theColumnmain data entry window to enter theColumn Tray Efficiencywindow. The efficiency model is selected with a radio button and the

Efficiency Data… button is clicked to begin tabular entry of tray effi-ciencies. Tray efficiencies may be given for all components on a tray orselected components on a tray. An overall scaling factor may also beprovided to be applied to all tray efficiencies. This factor may be adjustedby aControllerunit to meet a desiredSPEC.

Side ColumnsA column using theInside-Outor Surealgorithm may have attachedSide Columns, where aSide Columnis a stripper or rectifier. TheSideColumndraws feed from the mainColumnand returns a product to themainColumn. A finished product is withdrawn from theSide Column.

Side Columnsare attached as part of the flowsheet construction in thePFD main window. They may be completed and edited by double-clicking on the side column icon on the PFD. The side column dataentry windows are identical to theColumnmain data entry windowswith the exception that irrelevant features are eliminated.

The Inside-Outalgorithm merges a side column with the main columnfor calculations. This simultaneous approach means that theSPECsandVARYsfor the main column and side columns need not be balancedprovided that theSPECsandVARYsfor the total column configurationare balanced.


TheSurealgorithm solves side columns as separate columns in recycle.This approach is more time consuming, and demands that theSPECsandVARYsfor the main column and every side column are balanced.

TheChemdistalgorithm does not permit side columns.

Print OptionsClick the Print Options… button on theColumnmain data entrywindow to enter theColumn Print Optionsdata entry window. Selectthe desired report options with the check boxes provided. To requestplotted results, click the Plot Column Results… button and select thedesired plots with the check boxes on theColumn Plot Optionsdataentry window.

Thermodynamic OptionsA thermodynamic system is required for the equilibrium calculationson each tray. The thermodynamic system may be changed from theglobal default in theColumn Thermodynamic Systemsdata entrywindow which is reached by clicking theThermodynamic Systems…

button on theColumnmain data entry window. A single thermody-namic system may be defined for the complete column or differentsystems may be used in individual sections of the column.

If a vapor/liquid equilibrium thermodynamic system is used for part ofa column with the Chemdist algorithm, additional checks may beperformed to determine which trays have two liquid phases by clickingtheTest for VLLE or VLETrays check box. Thethermodynamic systemis then changed to a vapor/liquid/liquid system for those trays.


COLUMN, LIQUID-LIQUID EXTRACTIONGeneral InformationTheColumnunit operation may be used to simulate any distillation orliquid-liquid extraction process. Distillation columns are described intheDistillation Columnsection of this chapter. Although liquid-liquidextraction (llex) columns are generally not trayed, the distillationcolumn nomenclature is used and the termtray denotes an equilibriumstage. ALiquid-Liquid Extraction Columnmust contain at least twotrays.

The trays are considered to be linked with the light liquid phase movingup the column and the heavy liquid moving down. There is no limit onthe number of trays in a liquid-liquid extraction column model. Anytray may have a feed, product draw, or duty. Theremustbe a feed tothe top and bottom trays.

Note: Side columns may not be used with liquid-liquid extraction columns.

The following distillation column features are not applicable to LLEXcolumns and will be disabled:

● Condenser and reboiler

● Pumparounds

● Tray hydraulics

● Tray efficiencies.

Feeds and ProductsColumn feeds and products are added as part of the flowsheet construc-tion in the PFD. They may be accessed from theColumn Feeds andProductswindow accessible via theFeeds and Products… icon on theColumnmain data entry window.

Feed tray numbers may be added or changed in this window. There isno limit on the number of feeds a column may have.

For products, the product type, phase, tray number, and flowrate aresupplied in this window. There is no limit on the number of products aliquid-liquid extraction column may have and products may bewithdrawn from any tray of the column. Product types include:Overhead, Bottoms, Fixed Rate Draw, and Pseudoproduct. Everycolumn must have an overhead product leaving tray one and a bottomsproduct leaving the highest numbered tray. The product phase may beLight Liquid (Liquid 1) or Heavy Liquid (Liquid 2).


Product rates must be supplied for all draw products. Rates may besupplied in molar, mass, or liquid volume units. An estimated valuemust also be provided foreither the overhead or bottoms product. Theestimated value for the overhead or bottoms rate should be as accurateas possible to enhance convergence. It is necessary to use a Perform-ance Specification to set a desired flow for the overhead or bottomsproduct.

PseudoproductsPseudoproducts are used to create streams corresponding to columninternal streams, making them available for flowsheet calculations.Pseudoproducts are defined in theColumn Pseudoproductswindowaccessible via thePseudoproducts… button on theColumn Feeds andProductswindow. The following types of pseudoproducts areavailable:

Net tray light or heavy liquid flow

Total tray light or heavy liquid flow

Column AlgorithmThe solution algorithm is selected in the drop-down list box on theColumnmain data entry window. TheInside-Out(default),Sure, andChemdistalgorithms are for distillation columns. To specify a liquid-liquid extraction column, select theLiquid-Liquid option.

Calculated PhasesWhen theLiquid-Liquid algorithm is selected, the phase system willautomatically be set to liquid/liquid.

Number of TraysThe number of trays in the model is entered in the data entry fieldprovided on theColumnmain data entry window. Every Column musthave at least two trays. There is no limit on the number of trays in aColumn.

Number of IterationsThe maximum number of trial solutions is supplied in the data entryfield provided on theColumnmain data entry window. The defaultvalue is 30 for theLiquid-Liquid algorithm.

Pressure ProfileThe pressure for every tray in a column model must be defined. Allcalculations are performed at the defined tray pressures. The traypressures are defined in theColumn Pressure Profilewindow which isreached by clicking thePressure Profile… button on theColumnmain


data entry window. Tray pressures may be supplied on an overall ortray by tray mode by choosing a radio button in this window.

For the overall mode, the top tray pressure must be supplied andeitherthe pressure drop per trayor the total pressure drop aross the column.A default value of zero is supplied for the pressure drop per tray and thecolumn pressure drop. All tray pressures are derived by linear applica-tion of the supplied pressure drop.

Individual tray pressures are supplied for the tray by tray mode. Notethat the top and bottom traysmustbe included when supplying a tableof individual tray pressures. Missing pressures are determined bylinear interpolation of supplied values.

Heaters and CoolersSide heaters and side coolers may supplied via theColumn SideHeaters/Coolerswindow accessible via theHeaters and Coolers…icon on theColumnmain data entry window. A negative duty indicatescooling; a positive duty is used for heating. There are no limits on thenumber of side heaters/coolers.

For each side heater/cooler, the following information must beprovided: tray number, a reference name, and the duty, with the appro-priate algebraic sign.

Initial EstimatesTheLiquid-Liquid algorithm uses an iterative solution technique,starting from an initial estimate of the tray temperature, flow andcomposition profiles. By default, the initial estimate is produced inter-nally using the initial estimate generator. User-supplied profiles maybe used to replace some or all of the values produced by the estimategenerator.

Click the Initial Estimates… button on theColumnmain data entrywindow to enter theColumn Initial Estimateswindow.

When using the initial estimate generator, profiles are determined by asimple material balance. Temperatures are determined from estimatedproduct compositions. You may optionally provide temperatureestimates for the top and bottom trays which replace values predictedby the estimate generator as well as an estimate of the ratio of the liquidflows on tray 1.

When the initial estimate generator is not used, the data which must besupplied as input profiles are tray temperatures and flows, either lightor heavy liquid, or a combination thereof. Note that the minimum datawhich may be supplied are the temperatures and flows for the top and


bottom trays for the column. While these are the minimum datarequired, they are rarely adequate to produce an acceptable initialestimate. It may also be desirable to provide solution profiles from aconverged solution to speed future calculations with a column model.

Initial profiles are entered in tables accessed by clicking the followingbuttons on theColumn Initial Estimateswindow: Net Vapor Rate… , ,

Vapor Composition… , Tray Temperature… , Liquid Composition…and Net Liquid Rate… . Composition estimates are rarely needed formost problems.

Performance SpecificationsPerformance specifications orSPECsmay be imposed on a liquid-liquid extraction column operation such that product stream flows orproperties, column internal flows, column tray temperatures, etc., are atdesired values in the solution. For eachSPEC, a degree of freedom orVARYmust be calculated. For a liquid-liquid extraction column, aVARYmay be a feed stream rate, heat duty, or draw rate. Furthermore,for convergence to be achieved, there must be a direct effect on all oftheSPECsby the collective set ofVARYs.

To supplySPECsand defineVARYs,access theColumn Specificationsand Variableswindow via the Performance Specifications… buttonon the mainColumndata entry window.SPECsandVARYsare enteredor edited via the hypertext strings. PRO/II requires that there be anequal number ofSPECsandVARYs. Thus, when aSPECis added ordeleted, you are required to add or delete aVARY.

SPECsandVARYsuse the general form in PRO/II and are discussedmore fully in theSPEC/VARY/DEFINEsection of this chapter. A list ofthe stream and liquid-liquid extraction column parameters which maybe used forSPECsandVARYsis also given in this section.

Convergence DataConvergence data include algorithm tuning parameters, tolerances, andhistory printout options forColumniterations. Open theColumnConvergence Datawindow via the Convergence Data… button on theColumnmain data entry window to enter these data. The tuningparameters are as follows:

Damping Factor: A damping factor of less than unity may be used toimprove convergence when the convergence is oscillating. A defaultvalue of 1.0 is supplied by PRO/II.


Error Increase Factor: This factor limits the increase in the sum of theerrors from iteration to iteration. PRO/II supplies a default value of100.

Note: The use of tuning factors usually increases the solution time.

Tolerances for the liquid-liquid extraction column equations may alsobe changed although this should rarely, if ever, be done andneveras ameans to reach a converged solution.

Tolerances are:

Liquid-liquid: The maximum liquid-liquid equilibrium tolerance (equalto the bubble point tolerance for VLE) for each tray. The default is 10-3.

Enthalpy Balance: The maximum heat balance error for each tray. Thedefault is 10-3.

Component Balance: The maximum relative component balance error foreach tray. The default is 10-3.

Printout of the liquid-liquid extraction column iterations is useful indiagnosis of a convergence failure. History printout for the iterationsmay be requested by clicking theConvergence Data… button andselecting the printout level desired.

Print OptionsClick the Print Options… button on theColumnmain data entrywindow to enter theColumn Print Optionsdata entry window. Selectthe desired report options with the check boxes provided. To requestplotted results, click thePlot Column Results… button and select thedesired plots with the check boxes on theColumn Plot Optionsdataentry window.

Thermodynamic OptionsA thermodynamic system which supports liquid/liquid equilibrium isrequired for the equilibrium calculations on each tray. The thermody-namic system may be changed from the global default in theColumnThermodynamic Systemsdata entry window which is reached byclicking the Thermodynamic Systems… button on theColumnmaindata entry window. A single thermodynamic system may be defined forthe complete column or different systems may be used in individualsections of the column.


COLUMN, SIDEGeneral InformationTheSide Columnunit operation models side strippers and side recti-fiers associated with a mainColumn. TheSide Columnmodel iscurrently restricted to theInside-Out, Enhanced I/OandSurealgo-rithms. SeeColumn Algorithmin theDistillation Columndiscussion(page 9-35) for further information on these methods.

Side Columnsalways use the same distillation algorithm as the mainColumn. Multiple Side Columnsattached to one mainColumnarepossible and, in fact, are common practice in the petroleum refiningindustry.

Feeds and ProductsSide Columnsare added to the flowsheet with theSide Columnuniticon and attached to the mainColumnwith the feed and productstreams. EverySide Columnhas at least one external product whichexits the complex column arrangement.

Solution MethodsSolution methods forSide Columnsvary with the algorithm. TheInside-Out (and Enhanced I/O) algorithm merges theSide Columnwiththe main column and solves the complex column arrangement simulta-neously. There are three benefits to this approach:

● The simultaneous method results in more precision in thesolution.

● The simultaneous solution is more efficient and uses lesscomputing time.

● The simultaneous solution provides more flexible productspecifications.

For example, the last benefit permits the use of both a D86 (5%) and aD86 (95%) specification for a side stripper product. To solve this sameset of specifications with theSuremethod requires the use of aMulti-variable Controllerunit wrapped around the main column/side columnunits.

TheSuremethod solves each side column separately from the maincolumn and uses recycle streams to relate the side column and maincolumn. While special recycle logic is used to converge the column/side column recycle problem, this method has three disadvantageswhen compared to theInside-Outcolumn simultaneous treatment:


● The solution is less precise since a recycle stream tolerance isused in addition to the column equation tolerances.

● The recycle approach is much slower.

● Main column variables (except the main column draw rate)cannot be directly related to the side stripper products. Thismakes it necessary to use controllers to solve for more than onespecification on a side product.

Additional Information on Side StrippersSide strippers are widely used to control the front end volatility (flashpoint) of liquid products such as diesel fuel and kerosene. The liquidproduct is drawn from the main column and charged to the top tray ofthe side stripper which typically has 6 to 10 actual trays. A strippingmedium (usually steam) is fed to the bottom tray of the side stripper tostrip about ten percent of the liquid feed (the lightest material) which isthen returned to the main column for further fractionation together withthe stripping medium. The stripped liquid is withdrawn from thebottom tray of the stripper as a finished product. Steam side strippershave an overall tray efficiency of about 25 percent and can be repre-sented with two theoretical trays.

A variation in side stripper design is the use of a reboiler on the bottomof the side stripper to "heat strip" the liquid feed. No stripping mediumis used for reboiled side strippers. The advantage of this arrangement isa smaller stripped vapor return stream to the main column whichreduces the vapor loading for the main column. Reboiled side strippershave higher tray efficiencies than those which use a stripping medium.Therefore, three to five theoretical trays are typically used to modelthese strippers.

Side strippers do not normally have any other items of equipment suchas condensers, pumparounds, side heaters/coolers, etc. Only the Suremethod permits the use of a condenser on a side stripper. This capa-bility may find utility when modeling some unusual types of columnconfigurations.

Additional Information on Side RectifiersSide rectifiers are used to remove heavy materials from vapor drawproducts by providing a rectification section. The vapor draw from themain column is fed to the bottom tray of the side rectifier which mayhave a large number of trays. The side rectifier must have a condenseror cooling duty at the top to condense the liquid reflux which is used torectify the vapor product.


The overhead product from the side rectifier is removed as a finishedproduct. The liquid from the bottom tray is returned to the maincolumn for further fractionation.

The side rectifier corresponds to the rectification section of a conven-tional distillation column. An overall tray efficiency of 45 to 55percent is reasonable for many applications.

Side rectifiers do not normally have other items of equipment such aspumparounds, side heaters/coolers, etc. Reboilers are never used forthese columns.


COMPRESSORGeneral InformationTheCompressorsimulates a single stage isentropic compression.Outlet conditions and work requirements may be determined usingeither an adiabatic or polytropic efficiency. Optional tabular input maybe used to determine performance from supplied curves for outletpressure or pressure ratio, head, work, and/or efficiency. An optionalaftercooler calculation may be included. Both VLE and VLLE calcula-tions are supported. Multi-stage compressors may be modeled bylinking single stage compressor units.

Feeds and ProductsA compressor operation may have multiple feed streams, in which casethe inlet pressure is assumed to be the lowest feed stream pressure.

Compressors may have one or more product streams. The productphase condition for units withoneproduct stream is automatically setby PRO/II. For compressors with two or more product streams, theproduct phasesmustbe specified in theProduct Phaseswindow whichis accessed by clicking theProduct Phases… button on theCompressormain data entry window. Note that for compressors withaftercoolers, the products correspond to outlet conditions from theaftercooler.

Product phases allowable include: vapor, liquid, decanted water, heavyliquid, and mixed phase (vapor plus liquid). Mixed phase is mutuallyexclusive with vapor and liquid products and is not allowed when fourproduct streams are specified.

Pressure, Work, or Head SpecificationThe pressure, work, or head specification is selected from a drop-down listbox in theCompressormain data entry window. At least one specificationmust be supplied for every compressor. Options include:

Outlet Pressure: The outlet pressure from the compressor.

Pressure Increase: The pressure rise across the compressor.

Pressure Ratio: Compression ratio (absolute outlet pressure/absoluteinlet pressure).

Work: Actual work for the compressor.

Pressure Curve: Click the Enter Curve… button to supply a curverelating volumetric feed rate to outlet pressure in theCompressorOutlet Pressure Performance Curvewindow.


Pressure Ratio Curve: Click the Enter Curve… button to supply acurve relating volumetric feed rate to compression ratio in theCompressor Pressure Ratio Performance Curvewindow.

Adiabatic Work Curve: Click the Enter Curve… button to supply a curverelating volumetric feed rate to adiabatic work in theCompressor WorkPerformance Curvewindow.

Polytropic Work Curve: Click the Enter Curve… button to supply a curverelating volumetric feed rate to polytropic work in theCompressor WorkPerformance Curvewindow.

Actual Work Curve: Click the Enter Curve… button to supply a curverelating volumetric feed rate to actual work (efficiency has been applied) intheCompressor Work Performance Curvewindow.

Adiabatic Head Curve: Click the Enter Curve… button to supply a curverelating volumetric feed rate to adiabatic head in theCompressor HeadPerformance Curvewindow.

Polytropic Head Curve: Click the Enter Curve… button to supply a curverelating volumetric feed rate to polytropic head in theCompressor HeadPerformance Curvewindow.

Actual Head Curve: Click the Enter Curve… button to supply a curverelating volumetric feed rate to actual head (efficiency has been applied) intheCompressor Head Performance Curvewindow.

Efficiency or Temperature SpecificationAn efficiency or outlet temperature specification may be selected froma drop-down list box in theCompressormain data entry window.Options are:

Adiabatic Efficiency: Compressor adiabatic efficiency in percent. This issometimes called the “isentropic” efficiency.

Polytropic Efficiency: Compressor polytropic efficiency in percent.

Outlet Temperature: Compressor outlet temperature. The efficiency iscalculated.

Single Adiabatic Efficiency Curve: Click the Enter Curve… button to supplya curve relating volumetric feed rate to adiabatic efficiency in theCompressor Efficiency Curvewindow.

Single Polytropic Efficiency Curve: Click the Enter Curve… button to supplya curve relating volumetric feed rate to polytropic efficiency in theCompressor Efficiency Curvewindow.

Multiple Adiabatic Efficiency Curve: Click the Enter Curve… button tosupply multiple curves at designated Compressor inlet or outlet pressures


which relate volumetric feed rate to adiabatic efficiency in theCompressor Multiple Efficiency Curveswindow.

Multiple Polytropic Efficiency Curve: Click the Enter Curve… button tosupply multiple curves at designated Compressor inlet or outlet pressureswhich relate volumetric feed rate to polytropic efficiency in theCompressor Multiple Efficiency Curveswindow.

Selection of an efficiency or temperature specification is optional, andif none is selected a default value of 100 percent adiabatic efficiency isused. Note that this corresponds to a perfect isentropic compression.

RPM Adjustment of Compressor CurvesCurves for head, work, and efficiency are usually based on a specificcompressor speed. Therefore, they should be adjusted when thecompressor is operated at a different speed. PRO/II performs adjust-ments for these curves when values are supplied for theReference RPM(curve basis) and theOperating RPM. Adjustments are based on thefan laws and are as follows:

[ ]Head Head RPM RPMref reference= /.2 0

[ ]Work Work RPM RPMref reference= /.3 0

[ ]Efficiency Efficiency RPM RPMref reference= /

Aftercooler OptionAn aftercooler may be added via theAftercooler… icon on theCompressormain data entry window and supplying the cooler outlettemperature and pressure drop in theCompressor Aftercoolerwindow.

Outlet Temperature EstimateAn estimate for the outlet temperature for the compressor may option-ally be supplied in theCompressormain data entry window to speedconvergence. Note that this is not the same as theOutlet Temperaturespecification.

Calculation MethodThe method used to calculate theCompressorhead may be selected byclicking the Calculation Method… icon on theCompressormain dataentry window to access theCompressor Calculational Modewindow.The method may be chosen with the radio buttons provided, withchoices as follows:

GPSA Engineering Data Book: TheGPSA Data Bookequation is used tocompute head.


ASME Power Test Code 10: The ASME Power Test Code 10 equation isused to compute head. This method, the default, is the most rigorous.

The compression ratio above which the head equation is used tocompute the isentropic/ polytropic coefficient may also be supplied in thiswindow. This entry only applies to the GPSA method, with a default valueof 1.15 supplied. Below this compression ratio, the GPSA “temperatureequation” is used to compute the isentropic/polytropic coefficients.

Relative Convergence Tolerance for Work SpecificationsFor compressors withWorkspecifications, a relative convergencetolerance may optionally be supplied in theCompressormain dataentry window. A default value of 0.001 is used when no value issupplied.

Maximum Outlet PressureFor compressors withWorkspecifications, a maximum outlet pressuremay optionally be supplied in theCompressormain data window. Theoutlet pressure will be reset to this value when the supplied workresults in a pressure exceeding this value.

Thermodynamic SystemThe thermodynamic system of methods to be used for compressorcalculations may be selected by choosing a method from theThermody-namic Systemsdrop-down list box on theCompressormain data entrywindow.


CONTROLLERGeneral InformationTheController simulates the action of a feedback process controlled byadjusting an upstream flowsheet parameter to achieve a specified resultfor a process stream or unit operation. A controller must have oneSPECificationand oneVARY, where theSPECmay be a streamflowrate or property, a unit operating condition, or aCalculator result.The control variable (VARY) must be a stream or unit operationflowsheet parameter that is otherwise at afixedvalue in the flowsheet.

SpecificationTheSPECificationis supplied via the appropriate underlined hypertextin theSpecificationfield of theFeedback Controllermain data entrywindow (accessed by double-clicking on the Controller flowsheet icon).By clicking the hypertext string Parameter, theParameterwindowappears in which you can select the unit parameter or stream parameterto use as theSPEC. TheSPECmay be a single parameteror a mathe-matical expression that relatestwo flowsheet parameters. You may nextenter thevalueand thetolerancefor theSPECby clicking on theappropriate linked text. See theSPEC/VARY/DEFINEsection of thischapter for further details on the generalizedSPECform used inPRO/II.

VariableThe control variable (VARY) is selected by clicking the linked textstring Parameterin theVariable field of theFeedback Controllerwindow. The Parameter window is used to designate the stream or unitparameter to use for theVARYin a manner analogous to that used inselecting theSPECabove. TheSPEC/VARY/DEFINEsection of thischapter gives more information on theVARYconcept. There you willalso find tables of the flowsheet variables that may be used forSPECsandVARYs in controller units.

Limits and Step SizesLimits and step sizes for the control variable may be supplied by clickingthe Limits and Step Sizes… button on theFeedback Controllerwindow. A maximum value, minimum value, and/or maximum changein the control variable may be entered in theLimits and Step Sizeswindow. Optionally, you may supply a value for the control variable for thesecond iteration by selecting the appropriate radio button to replace thedefault change of 2.0 percent of the initial control variable value. You mayspecify a different percentor value for the second iteration.


ParametersSeveral parameters regarding the operation of the Controller may besupplied on this section of theFeedback Controllerwindow. You maychange the maximum number of iterations from the default value of 10.Use the radio buttons may to select the action taken when the controlvariable exceeds the prescribed limits:

● The value is set to the limit as a solution and flowsheet calcula-tions continue (the default), or

● Flowsheet calculations are halted.

Print Results for Controller IterationsThe default is to print a summary for each controller iteration. To eliminatethis printout, deselect the check box on theFeedback Controllerwindow.

Next Unit Calculated After Control Variable is UpdatedOrdinarily this is the first unit operation in the calculation sequence thatis affected by the control variable and is determined automatically(“calculated”) by PRO/II. You may specify a different return unit byusing the drop-down list box on theFeedback Controllerwindow.

Non-convergence of ControllersThe controller uses a Newton-Rhapson technique to search for the value ofthe control variable that meets the specified flowsheet parameter result.Therefore, it is important that there be a continuous and monotonic rela-tionship between the control variable and the specification. Controlfunctions with discontinuities or localized maxima and minima may fail toconverge or converge to an undesired result.

For some cases, the limits and step sizes entries may keep the controlfunction within a range of feasible solutions.

Controllers and Recycle LoopsControllers always create a recycle loop in the flowsheet, from thedownstream unit at which the specification is evaluated to the firstupstream unit affected by the control variable.

When a controller is located within a recycle loop, PRO/II normally solvesthe controller as part of the loop, i.e., the controller iterations and therecycle iterations are solved simultaneously. Therefore, you must changethe calculation order when it is desired to converge the controller withineach iteration of the overall recycle loop. Note also that it is important thatthe tolerance for the controller be tighter than the tolerance for the overallrecycle loop to insure convergence.


CRYSTALLIZERGeneral InformationTheCrystallizerunit operation simulates crystallization processes forthe manufacture of organics, inorganics, fertilizers, biochemicals andpolymers. The crystallizer transforms a supersaturated solution into amixed solid/liquid crystal slurry.

The crystallizer is modeled as aMixed Suspension Mixed ProductRemoval(MSMPR) crystallizer orContinuous Stirred Tank Crystallizer(CSTC). These models assume ideal mixing in the unit and that theproduct conditions are the same as the bulk conditions. The model alsoassumes that breakage or agglomeration of solid particles is negligible.A feed heat exchanger may be included in the model with recirculationif required.

The crystallization process depends on phase equilibria as well askinetic or non-equilibrium considerations. Solid-liquid equilibrium isdefined in terms of solubility, which is calculated from either the Van'tHoff equation or user-supplied solubility data.

You must selectDesignor Ratingcalculations in theCrystallizerCalculation Modewindow. In design mode, a specification is requiredand the volume is calculated. In rating mode, the vessel volume isdefined.

The formation rate relationships are expressed as power law expres-sions in theCrystallizer Growth and Nucleation Rateswindow. Theserelationships are similar to equations for power law kinetics used forchemical reactions. Full details of the calculation method can be foundin thePRO/II Reference Manual.

Feeds and ProductsTheCrystallizercan have any number of feed streams. The inletpressure is taken to be the lowest pressure of all the feed streams.

Both an overhead and bottoms product must be specified in theCrystal-lizer Productswindow. The bottoms contains the crystals in thesolid/liquid slurry. The overhead contains any vapor generated in theunit.

Unit SpecificationA Crystallizerunit operation is specified by filling in the appropriatedata variables forSoluteandSolvent, Crystal Shape Factor, CalculationMode, Design Specification(in Design Mode) and Growth and Nuclea-tion Rates in the appropriate data entry windows that may be accessed


through theCrystallizermain data entry window that is accessed bydouble-clicking on theCrystallizerunit icon.

Crystal Shape FactorThe shape factor defaults to 1.0 which indicates cubic crystals. A valueof π/6 indicates spherical crystals.

Solute and SolventSelect the solute and solvent components. The solute must be definedas a liquid-solid component. If there are no liquid-solid componentsavailable in the simulation, a warning message is displayed prior toopening theCrystallizermain data entry window. To specify acomponent as liquid-solid, selectInput/Component Selection/Component Phases.

Calculation ModeClick on the Calculation Mode… button to specifyDesignor Ratingcalculation mode.

In Designmode, a specification is required and the vessel volume iscalculated. Specification options are:

Crystal Production Rate: Enter the production rate of the crystals inweight units.

Fraction of Solute Crystallized: Enter the fraction of the total solute in thecombined feeds that is to be crystallized.

Magma Density in the Bottom Product: Enter the density of the bottomproduct as weight of crystals per unit volume of slurry.

Supersaturation Ratio: Enter the supersaturation ratio which is defined as:

(Xexit-Xsat)/Xsat

where:Xexit is the liquid phase mole fraction of the solute in the bottomproduct, andXsat is the saturation mole fraction of the solute in the bottom prod-uct.

In Ratingmode, the vessel volume is defined.

Growth and Nucleation RatesClick on the Growth and Nucleation Rates… button to specify Growthand Nucleation Rates.

Crystal Growth Rate You must supply theRate Constantfor the rateequation in ft/sec or m/sec. Growth rates are typically in the range2.0x10-7 to 2.0x10-8 m/sec. By default, the rate is directly proportional


to theSupersaturation Ratio. You may change this by overriding thedefaultExponential Factor. Factors are usually in the range 0.0 to 2.5.

Crystal Nucleation Rate TheNucleation Rateis the number of crystalsnucleated per unit time per unit liquid volume. You must supply theRate Constantfor nucleation and specify its dimensional units. Bydefault, the rate is directly proportional to theSupersaturation Ratio.You may change this by overriding the defaultExponential Factors.Typical values for theSupersaturation Ratio Factorare in the range 0.5to 2.5 for secondary nucleation and up to 10 for primary nucleation. Ifan exponent is specified for theImpeller Speed, you may need tochange the default value of 100 RPM.

Operating ConditionsClick on the Operating Conditions… button to specifyCrystallizerOperating Conditions.

By default, the crystallizer operates at the combined feed temperatureand pressure with no recirculation.

Pressure Specification The pressure may be specified as a drop below thecombined feed pressure or you may specify the pressure value directly.

Second Specification If an option other thanAt Merged Feed Temperatureis selected, the unit is assumed to include a feed heat exchanger. Youmay specify either the crystallizer operatingTemperatureor theDuty ofthe exchanger.

Recirculation Flowrate Some of the bottom product may be remixed withthe feed and passed through the feed exchanger. To specify this option,you must either specify the recirculationVolumetric Rateor theTemperature Changeacross the exchanger. Anegativechange denotesa temperature drop.

Alternatively, instead of entering a numeric value for the parameters inthis window, they may be referenced using theDEFINE system relativeto any available unit operation or stream parameter calculatedelsewhere in the simulation. See the table ofCrystallizer Parametersavailable for Cross-Referencingin the online help for more details.

Print OptionsClick on the Print Options… button to access theCrystallizer PrintOptionswindow.

Check theInclude Crystal Size Distributionbox to request additionaloutput including tables of fractions and population densities for thefeed and product streams as functions of the crystal size distribution.


CYCLONEGeneral InformationTheCycloneunit operation models the separation of particulate solidsfrom a solid and gas stream. The particulate collection efficiency isdetermined by the solids loading, component characteristics, particlesize distribution, stream flow rate, and cyclone geometry. TheCycloneunit operation will calculate the collection efficiency for every particlesize range of each solid component as well as the pressure drop throughthe unit. TheCycloneis assumed to operate isothermally and mecha-nisms such as agglomeration and crumbling are discounted.

Feeds and ProductsA Cyclonemay have up to ten feed streams. Unless otherwisespecified, the inlet pressure will be taken as that of the feed stream withthe lowest pressure. The feed streams may not contain a liquid phase,and there must be two product streams. The overhead stream willcontain all the gas that comes in as well as any uncollected solids. Thebottom stream will contain only the collected solids. All solid compo-nents that enter a cyclone must have a particle size distribution. Thisdistribution may be set by another unit or defined by the user.

Unit SpecificationA cyclone unit operation is specified by filling in the appropriate realand integer data variables for operating mode, geometry, pressure dropcalculations, efficiency calculations, and multiple cyclone configurationin theGas/Solid Cyclonemain data entry window that is accessed bydouble-clicking on theCycloneunit icon on the PFD.

Rating Mode:If you selectRating Mode, you must supply the diameter of thecyclone. The other dimensions of the cyclone will be generated fromthe diameter. If you selectUser Defined Geometry,you must also enterall of the geometric ratios as described below. InRating Mode, PRO/IIwill calculate: pressure drop, total efficiency, component efficiencies,grade efficiencies and weight percent solids in the overhead stream.

Design Mode:If you selectDesign Mode, you do not need to provide the cyclonediameter. Again, if you selectUser Defined Geometry,you must enterall of the geometric ratios as described below. In addition, you mustspecify a target for total solids collection (see entry forRPARM(13)below). You may also wish to override the default maximum pressuredrop of 10 inches of water by entering a value in whatever input


pressure units you prefer (see entry forRPARM(16) below). In additionto the normalRating Modeoutput,Design Modewill calculate thenumber and size of identical cyclones that are necessary to meet thespecification. There may be many cyclone systems that meet the speci-fication. In all cases,Design Modewill return the system requiring thefewest cyclones.

Multiple CyclonesTheCyclonecan model a system of identical cyclones that are arrangedeither inparallel or in series. In the case ofparallel cyclones, the feedstreams are split evenly among the cyclones. The overhead productsfrom all cyclones merge into one overhead and the bottoms productsfrom all cyclones merge into one bottom stream. In the case ofseriescyclones, the overhead from the first cyclone is the feed to the secondand so on. The overhead product is the overhead product from the finalcyclone while the bottom product is the combined bottom product fromall the cyclones in the system. Both product streams are at the outletpressure of the final cyclone in the system. It is not possible to specifyrecycle streams inside the unit or to reference intermediate stage datafrom the flowsheet. For example, if you wish to set a specification onthe second cyclone in a three-cyclone series or set a recycle from thesecond cyclone to the first cyclone, you should model the system asthree separate units. Note that while increasing the number of identicalcyclones willincreaseefficiency and pressure drop in a series system, itwill decreasethe efficiency and pressure drop in a parallel system.

Integer Data for UnitCalculation Mode (IPARM(1)) This input is optional. Options are:

1 Rating (default)2 Design

Efficiency Model (IPARM(2)) This input is optional. Options for Rating andDesign mode are:

1 Koch & Licht2 API (default)3 Lapple

The Lapple model is based on a ratio of particle diameter to cut di-ameter (the diameter of the particles which are collected with 50%efficiency). The API method is based on a ratio of particle diameterto critical diameter (the diameter of particles which would be col-lected at 100%). The Koch & Licht method is not based on a parti-cle size ratio.

Pressure Model (IPARM(3)) This input is optional. Options for both Ratingand Design mode are:


1 Koch & Licht (default)2 API

If the cyclone is inside another vessel, the API method allows val-ues for theInlet Width Ratioand theSuperficial Gas Velocity(de-scribed later in the section titled Real Data for Unit) to be specified.

Cyclone Geometry (IPARM(4)) This input is optional. Options for bothRating and Design mode are:

1 Stairmand (default)2 High efficiency Swift3 Lapple4 General purpose Swift5 Peterson & Whitby6 User defined geometry

If the user defined geometry is used, values must be specified forthe inlet height ratio, inlet width ratio, cyclone dust outlet diameterratio, cyclone gas outlet diameter ratio, gas outlet tube length ratio,height of cylindrical section ratio, and total cyclone height ratio asappropriate for the calculation method used as shown.

Inlet Vane Flag (IPARM(5)) This input is optional. Options for both Ratingand Design mode are:

1 No (default)2 Yes

Shape of Gas Inlet Flag (IPARM(6)) This input is optional. Options for bothRating and Design mode are:

1 Tangential (default)2 Scroll or volute3 Axial

Cyclone is inside Vessel Flag (IPARM(7)) This input is optional. Options forboth Rating and Design mode are:

1 No (default)2 Yes

For a value of 2, theInlet Width Ratioand theSuperficial Gas Ve-locity must be specified.Dipleg Sizeis calculated if the value of 2is entered.

Efficiency Adjustment Due to Loading Flag (IPARM(8)) This input is optional.Options for both Rating and Design mode are:

1 Adjust (default)2 Do not Adjust


Automatically Switch Pressure Drop Model (IPARM(9)) This input is optional.Options for both Rating and Design mode are:

1 Do not Switch (default)2 Switch

This entry allows changes to be made automatically in the pressuredrop model between the Koch & Licht and API methods based onsolids loading.

Configuration of Multiple Cyclones Flag (IPARM(10)) This input is optional.Options for both Rating and Design mode are:

1 Parallel (default)2 Series

Number of Identical Cyclones (Series or Parallel) (IPARM(11)) This input isoptional and is for Rating Mode only. The default value is 1 cyclone.

Number of Particle Size to be Specified (IPARM(12)) This input is optional andis for Rating Mode only.

This and the following entry can be used together to specify thecomponent and PSD size range whose weight fraction in the over-head will be output toRPARM(64). This latter value can be ac-cessed by aController, MVC or Optimizer.

For example, if a solid with PSD data: 10, 20, 30, 40 (in default in-put units) is required to have a weight fraction of 0.20 in size range20 to 30, the value for this entry would be 2 (the second size range)and the value for aDEFINE statement would be 0.20. The defaultvalue is 1 (the first size range).

Number of the Component to be Specified (IPARM(13)) This input is optionaland is for Rating Mode only.

This optional input is the number of the component with particlesize distribution data to be used in the design. The default is thefirst solid component with a PSD that the design mode may evalu-ate.

Maximum Number of Cyclones (IPARM(14)) This input is optional and is forDesign Mode only.

The value indicates the number of cyclones in parallel or series asappropriate based on the value specified above for theConfigura-tion of Multiple Cyclones Flag.The default is 20 for parallel and 3for series.


Real Data for Unit

The cyclone geometry is input as the ratio of length divided by overallcyclone body diameter, so that an inlet height of 0.1 meters on acyclone of diameter 0.2 meters would have an inlet height ratio of0.1/0.2 = 0.5.

Diameter of Cyclone Cylinder (RPARM(1)) This input isrequiredand is forRating Mode only.

Inlet Height Ratio (RPARM(2)) This Rating/Design Mode entry is optional.

Inlet Width Ratio (RPARM(3)) This Rating/Design Mode entry is optional.

Cyclone Dust Outlet Diameter Ratio (RPARM(4)) This Rating/Design Modeentry is optional.

Cyclone Gas Outlet Diameter Ratio (RPARM(5)) This Rating/Design Modeentry is optional.

Gas Outlet Tube Length Ratio (RPARM(6)) This Rating/Design Mode entry isoptional.

Height of Cylindrical Section Ratio (RPARM(7)) This Rating/Design Modeentry is optional.

Total Cyclone Height Ratio (RPARM(8)) This Rating/Design Mode entry isoptional.

Diameter of Vessel Housing (RPARM(9)) This Rating/Design Mode entry isoptional.

Superficial Gas Velocity (RPARM(10)) This Rating/Design Mode entry isoptional.

Pressure Drop to Inlet (RPARM(11)) This Rating/Design Mode entry isoptional. This value is the pressure drop between the feed stream andthe inlet to the cyclone. The default is 0.0.

Absolute pressure at cyclone inlet (RPARM(12)) This Rating/Design Modeentry is optional. For use if cyclone inlet pressure differs from feedstream pressure. The default is the lowest feed stream pressure.

Goal Efficiency for Design Mode (wt%) (RPARM(13)) This Design Mode entryis required.

Minimum Cyclone Diameter (RPARM(14)) This Design Mode entry isoptional. The default is 0.1 m.

Maximum Cyclone Diameter (RPARM(15)) This Design Mode entry isoptional. The default is 0.5 m.


Maximum Pressure Drop (RPARM(16)) This Design Mode entry is optional.This value is the maximum pressure drop across cyclones in a unit Thedefault is 2.488 kPa.

Tolerance for Cyclone Body Diameter (RPARM(17)) This Design Mode entry isoptional. The default is 0.001.

Real Number Output from Cyclone

The output values calculated by theCyclonemodel are stored in theindicated locations in theRPARM() array and can be accessed by aController, MVC or Optimizer.All RPARM() outputs are produced inboth Rating and Design modes.

Overall Efficiency (wt%) (RPARM(51)) In Design mode, this is an input valueincluded in the output report for the cyclone unit.

Diameter Of Cyclone Cylinder (RPARM(52)) In Rating mode, this is an inputvalue included in the output report for theCyclonemodel.

Pressure Drop (RPARM(53)) This is adjusted for loading by the user.

Total Solids In Overhead (RPARM(54)) This is the weight % of the totaloverhead stream.

Inlet Height Dimension (RPARM(55))

Inlet Width Dimension (RPARM(56))

Cyclone Dust Outlet Diameter Dimension (RPARM(57))

Cyclone Gas Outlet Diameter Dimension (RPARM(58))

Gas Outlet Tube Length Dimension (RPARM(59))

Height of Cylindrical Section Dimension (RPARM(60))

Total Cyclone Height Dimension (RPARM(61))

Dipleg diameter (RPARM(62)) This requires that the cyclone be locatedabove a fluidized bed, i.e., the cyclone must be located inside a vessel.This value is output in the cyclone output report only if applicable.

PSD weight fraction in the overhead RPARM(64) This value is the particle sizedistribution weight fraction in the overhead of the size and componentspecified. See entries forIPARM(12) andIPARM(13) above. This is theratio of weight in the specified size range divided by the weight of thecomponent in the overhead. This value is output in the cyclone outputreport only if applicable.


DEPRESSURING UNITGeneral InformationTheDepressuring Unitsimulates the time-pressure-temperature rela-tionships that occur when a vessel is depressured through a relief orcontrol valve. Several different valve models, vessel configurations andmodels for heat flow into the unit are available. An optional externalmakeup stream may also be specified. The initial phase of the vesselcontents may be either a vapor or a vapor-liquid mixture.

Calculation options include procedures from API Standard 2000, APIRecommended Practice 520, and other industry standards.

Initial Relief ConditionsThe initial relief conditions can be based on either a specified initaltime or a specified inital pressure by selecting the appropriate radiobutton. The default selection is to start the depressuring calculations atthe beginning of the simulation (time zero.)

Note: This option is only available if the heat input model type “FireRelief Model” is selected.

Final Depressuring ConditionsTo set the final depressuring conditions, values may be entered foreither or both finalVessel PressureandElapsed Time. The elapsed timecan be measured fromTime Zeroor from theStart of Reliefby choosingthe desired toggle text. If both finalVessel PressureandElapsed Timeare selected, the depressuring calculations will stop when the firstcriterion is satisfied.

Time Step Size Calculation OptionsUser-supplied values for the relative volume tolerance per time step, themaximum number of time steps, and the time step size can be enteredon theCalculation Optionswindow. This window is brought up byclicking the Calculation Options… icon on theDepressuring Unitmain data entry window.

The default value for theVolume Tolerance per Time Stepis 0.0001.The default value for theMaximum Number of Time Stepsallowed inthe depressuring simulation is 100.

The default value for theTime Stepsize is calculated using defaultvalues for the sizing parameters. User-supplied values for the parame-ters used in this calculation may be entered via the appropriatehypertext string. The step size basis is selected from a pop-up list,


which includes(1) total fluid quantity in increments of the amount*(a constant)(2) vapor quantity in increments of the amount*(a constant), or(3) the smaller of (1) or (2).

The default selection for time step size basis is (1). If either (1) or (2)is selected, a user-supplied value for the constants can be entered in thepop-up float field. For the time step size basis of (1), the default valueof the constant is 0.04. For (2), the default value of the constant is 0.50.

Specification of Isentropic EfficiencyEither the default isentropic efficiency or a user-supplied value may beused in the blowdown calculations by selecting the appropriate radiobutton on theDepressuring Unit - Calculation Optionswindow. For allheat flow models except forRigorous Blowdownor SemirigorousBlowdown, the default value is 0.0. IfRigorous Blowdownor Semirig-orous Blowdownis selected for theHeat Flow Model, the default isen-tropic efficiency is 1.0.

Action when Errors are DetectedBy default, the simulation will stop if pressure profile errors aredetected. Clicking on the Stophypertext on theCalculation Optionswindow toggles the option to Continueand allows the simulation tocontinue even if pressure profile errors are detected.

Valve DataData can be entered on theDepressuring Valve Datawindow to definethe flow characteristics of the relief valve or control valve. Thiswindow is brought up by clicking theValve Data… button on theDepressuring Unitmain data entry window. AValve Modelmust beselected from the four choices by choosing the appropriate radio button.The available valve models areSupersonic Flow, Subsonic Flow,Constant Flow, andUser Model. The default isSupersonic Flow. Theequation for the selected model is displayed as an aid to entering theparameters in the valve equation. The units displayed for the equationare consistent with the default UOM for the problem and may not bechanged.

A Valve Constant (C)must be entered for all models except for theUser Model. For theSupersonic Flowmodel, the valve constant is theonly entry allowed. For theSubsonic Flowmodel, an optional backpressure may be entered along with the required the valve constant. FortheConstant Flowmodel, the only allowable entry is the valveconstant. For theUsermodel, the control valve coefficient must beentered. The default back pressure value is 0.0, while the default value


for the critical flow factor is 1.0 Different values for the back pressureand critical flow factor may be entered.

Vessel DataTheDepressuring Vessel Datawindow is used to define the configura-tion of the depressuring unit. This window is accessible via the

Vessel Data button on theDepressuring Unitmain data entry window.One of the following,

SphereHorizontal CylinderVertical CylinderUnspecified Shape

must be selected by choosing the appropriate radio button.

If Sphereis the selected vessel geometry, a value for the diametermustbe entered. IfHorizontal Cylinderis the selected vessel geometry, thediameter and tangent-to-tangent lengthmustbe entered. For theVertical Cylindervessel geometry, the diameter and tangent-to-tangentheightmustbe entered. For vessels of any of these defined geometries,entering a value for liquid height is optional. For vessels of theUnspecified Shapegeometry, the vessel volumemustbe entered.Liquid Holdupis optional only if the geometry isUnspecified Shape.By default, the holdup liquid is saturated liquid of the combined feedcomposition at the initial conditions. The remaining vessel volumecontains vapor in equilibrium with this liquid. The holdup may be on amole, weight, or actual volume fraction basis with the default being themole fraction basis.

TheVessel Weightand theVessel Specific Heatmay be input for anyvessel geometry. If one of these two variables is entered, then bothmustbe entered. These items arerequiredonly if “Blowdown” appearson theHeat Inputwindow, otherwise they are optional. (See discussionon vesselHeat Inputoptions below.)

The volume correction factor is an optional entry for theSphere, Hori-zontal Cylinder, andVertical Cylindervessel geometries only. Thisentry is used to correct the vessel volume for pipes, fittings, and endplates and defaults to 1.00 if not supplied.

Heat InputClick the Heat Input… icon on theDepressuring Unitmain data entrywindow to open theHeat Inputwindow. A heat input model may beselected from the drop-down list box, which includes the followingoptions:

User-defined


API 2000API 2000 Method with ScalingAPI RP 520 with ScalingAPI RP 520IsothermalRigorous BlowdownSemirigorous BlowdownFire Relief.

User-Definedis the default as this supplies no heat input to the vessel.The difference between theRigorousandSemirigorous Blowdownmodelsis the physical property calculations. The selected heat transfer equation isdisplayed, along with the equation’s units of measure. Depending on theHeat Flow Modelselected, from one to five of the coefficients may besupplied. For theUser-Definedor Semirigorousor Rigorous Blowdownmodels, values for these coefficients default to 0.0.

For theFire Relief Modelonly, the first two coefficients C1 and C2 arerequired.

The Initial WettedArea field is made unavailable when a value has beenentered forLiquid Heighton theVessel Datawindow. Otherwise, avalue forInitial Wetted Area mustbe entered for the API 2000, ScaledAPI 2000, RP 520, Scaled RP 520, and Fire Relief Models. TheAreaScaling Factoris an optional entry for these same heat input modelsonly when theInitial Wetted Areais input. It has a default value of 1.0.

TheHeat Input Scaling Factormay be input for any heating modelexcept theSemirigorousandRigorous BlowdownandIsothermalmodels. It has a default value of 1.0.

For the heat transfer coefficient used in theSemirigorousor RigorousBlowdowncalculations, either aCalculated Using Scaling Factorcoef-ficent, anOverall coefficient, or individual phase vapor or liquid heattransfer coefficient may be used by selecting the appropriate radiobutton. The default is to use theCalculated Using Scaling Factorcoef-ficent, with a default value for the scaling factor of 1.0.

Makeup StreamOne feed stream to the depressuring unit can be designated as aconstant-rate makeup stream. Click theMakeup… icon on theDepres-suring Unitmain data entry window to open theMakeup Streamwindow, where a makeup stream can be designated. Checking the boxenables a drop-down list box which contains the names of all feedstreams to the depressuring unit shown on the PFD. One stream may beselected as a makeup stream. The flow of this stream will always begin


at time = 0, regardless of when the depressuring begins. By default, nomakeup stream is included.

Print Results for Depressuring UnitThePrint Optionswindow allows the user to control the intermediateand final printed results for theDepressuring Unit.This window can beaccessed through theOutput/Report Format/Unit Operationsmenuoption or from theDepressuring Unitmain data entry window..

The default for all stream printout is a molar basis; clicking on thetoggle text allows the user to select weight basis.

By default, component compositions are printed at all steps. The usermay opt to print all steps, or initial, final and relief conditions onlybyclicking on the hypertext. The user may suppress all compositionprintout by deselecting the box.

Intermediate printout is printed at each calculation step time by default.The user may select a different interval by clicking on the default timestep linked text, which will bring up theIntermediate Print IntervalOptionswindow. On theIntermediate Print Interval Optionswindow,either theDefault Time Step, aUser-defined Time Step, or aUser-defined Pressure Intervalcan be specified for the printing frequency ofthe intermediate results by selecting the appropriate radio button.

Thermodynamic SystemFor problems where more than one thermodynamic method has beenspecified, a drop-down list box allows the selection of a thermodynamicmethod set to be used for theDepressuring Unit.


DISSOLVERGeneral InformationTheDissolverunit operation models the dissolution of solids into liquidsolutions. This mass transfer operation is widely used in the chemicalindustry in both organic as well as inorganic processes.

Feeds and ProductsThe dissolver unit can have any number of feed streams. The inletpressure is taken to be the lowest pressure of all the feed streams.

Both an overhead and bottoms product must be specified. The defaultallocation may be modified in theDissolver Productswindow. Thebottoms contains the liquid product along with any remaining crystals.The overhead contains any vapor generated in the unit.

Calculation MethodThe dissolver transforms crystals in solution from the solid to the liquidphase. PRO/II models the most common type of dissolver which is thestirred tank dissolver. A feed heat exchanger may be included in themodel if required.

A Solid-liquid equilibrium method must be defined in terms of solu-bility, which is calculated from either the Van't Hoff equation or user-supplied solubility data.

You must selectDesignor Ratingcalculations in theDissolver Calcula-tion Modewindow. InDesignmode, a specification is required and thevolume is calculated for a given feed particle size distribution andoperating conditions. InRatingmode, the vessel volume is defined andthe exit particle size distribution is determined.

The mass transfer coefficient may be specified in theDissolver Dissolu-tion Ratewindow. Alternatively, you may specify that the coefficientshould be calculated from diffusivity data entered in the Thermody-namic Data.

Full details of the calculation method can be found in thePRO/IIReference Manual.


EXPANDERGeneral InformationTheExpanderoperation may be used to model any isentropicexpansion such as an expander unit in a natural gas processing plant ora steam turbine, etc. An adiabatic expansion efficiency may be appliedto the calculations. Rigorous calculations may be performed for bothVLE and VLLE systems.

Feeds and ProductsAn expander operation may have multiple feed streams, in which casethe inlet pressure is assumed to be the lowest feed stream pressure.

An expander may have one or more product streams. The productphase condition for operations withoneproduct stream is automaticallyset by PRO/II. For expanders with two or more product streams, theproduct phasesmustbe specified in theExpander Product Phaseswindow which is accessed by clicking theProduct Phases… buttonon theExpandermain data entry window.

Allowable product phases include: vapor, liquid, decanted water, heavyliquid, and mixed phase (vapor plus liquid). Mixed phase is mutuallyexclusive with vapor and liquid products and is not allowed when fourproduct streams are specified.

Pressure and Work SpecificationsThe outlet conditions for an expander may be selected with the radiobuttons provided on theExpandermain data entry window. A pressure orwork specification is required for every expander. Options are as follows:

Outlet pressurePressure ratio (absolute outlet pressure/absolute inlet pressure)Pressure dropWork

A relative tolerance in percent may also be defined for convergence ofwork specifications. If none is given, a default value of 0.001 percent isused.

Adiabatic EfficiencyThe isentropic work is adjusted by application of the adiabatic effi-ciency supplied in theExpanderwindow. When not supplied, a defaultvalue of 100 percent is used (perfect isentropic expansion).


Minimum Outlet PressureFor expanders with Work specifications, a minimum outlet pressuremay optionally be defined in theExpandermain data entry window. Thework will be reset as needed so this minimum pressure is not violated.

Outlet Temperature EstimateAn estimate for the outlet temperature may be optionally supplied intheExpandermain data entry window to speed the calculations.

Thermodynamic SystemThe thermodynamic system of methods to be used for expander calcu-lations may be selected by choosing a method from theThermodynamicSystemdrop-down list box on theExpandermain data entry window.


FLASHGeneral InformationTheFlashunit may be used to model any equilibrium calculationwhere two of the conditions are defined, e.g., temperature and pressure,pressure and enthalpy, etc. The phase equilibrium is determined andthe product may be separated into product streams corresponding to thephases. The duty required, if any, to bring the feed to the final condi-tions is also reported. Both VLE and VLLE calculations are supportedby this unit.

Feeds and ProductsA flash operation may have multiple feed streams, in which case theinlet pressure is assumed to be the lowest feed stream pressure.

A flash may have one or more product streams. The product phasecondition for flash operations withoneproduct stream is automaticallyset by PRO/II. For flash units with two or more product streams, theproduct phasesmustbe specified in theFlash Product Phaseswindowwhich is accessed by clicking theProduct Phases… button on theFlashmain data entry window.

Product phases allowable include: vapor, liquid, decanted water/secondliquid, and mixed phase (vapor plus liquid). Mixed phase is mutuallyexclusive with vapor and liquid products and is not allowed when fourproduct streams are specified. Note that forDew PointandBubble Pointcalculations only two product phases are allowed, vapor and liquid. Theoptional liquid product from aDew Pointcalculation corresponds to apseudostream with the equilibrium liquid composition and the optionalvapor product from aBubble Pointcalculation corresponds to the equilib-rium vapor composition.

First SpecificationThe temperature, pressure, or pressure drop from feed conditions issupplied by choosing the appropriate drop-down list box on theFlashmain data entry window and supplying the value in the data entry fieldprovided. Only one entry is allowed.

Second SpecificationThis specification is used in conjunction with theFirst Specificationgivenabove to define the equilibrium calculation desired. TheSecond Specifica-tion may beeitheraUnit Specificationor aProduct Specificationasdenoted by the radio buttons on theFlashmain data entry window. Thesetwo types of specification are discussed separately below.


Unit SpecificationThe desired second specification is chosen with the drop-down list boxand the data entry supplied in the field provided. Options are:

Pressure Drop or Pressure: These entries are only applicable when thetemperature is chosen as the primary specification and correspond to anisothermal (constant temperature and pressure) flash. TheDuty required tobring the feed to the specified conditions is calculated by PRO/II.

Duty: This entry corresponds to an adiabatic (duty defined) flash. Whenthe temperature is supplied as the primary specification, the pressure iscomputed. When the pressure or pressure drop is supplied as the primaryspecification, the temperature is computed. The duty may be positive(heating), negative (cooling), or zero (constant enthalpy calculation).

Dew Point: The dew point pressure is computed when the temperature issupplied as the primary specification. The dew point temperature isdetermined when the pressure or pressure drop is provided as theprimary specification. TheDuty required to bring the feed to thespecified conditions is calculated by PRO/II.

Hydrocarbon Dew Point: The dew point pressure for the hydrocarbonportion of the stream is computed when the temperature is supplied asthe primary specification. The dew point temperature is determinedwhen the pressure or pressure drop is provided as the primary specifica-tion. This option is only applicable for thermodynamic systems whichsupport a free water phase. TheDuty required to bring the feed to thespecified conditions is calculated by PRO/II.

Water Dew Point: The dew point pressure for the water portion of thestream is computed when the temperature is supplied as the primaryspecification. The dew point temperature is determined when thepressure or pressure drop is provided as the primary specification. Thisoption is only applicable for thermodynamic systems which support afree water phase. TheDuty required to bring the feed to the specifiedconditions is calculated by PRO/II.

Bubble Point: The bubble point pressure is computed when the tempera-ture is supplied as the primary specification. The bubble point tempera-ture is determined when the pressure or pressure drop is provided as theprimary specification. TheDuty required to bring the feed to thespecified conditions is calculated by PRO/II.

Isentropic: A constant entropy flash is calculated from feed conditionsto final conditions. The product pressure is computed when tempera-ture is given as the primary specification. The product temperature isgiven when the pressure or pressure drop is given as the primary speci-


fication. TheDuty required to bring the feed to the specified conditionsis calculated by PRO/II.

Product SpecificationWhen this radio button is selected, the pressure is computed when thetemperature is provided as the first specification such that acalculatedstream parametermeets a specified value. When the pressure orpressure drop is supplied as the first specification, the temperature iscomputed. TheDuty required to bring the feed to the final conditions isalso calculated by PRO/II.

The stream parameter specification is entered by clicking on thehypertext strings and uses the general PRO/II specification format.This format is further described in theSPEC/VARY/DEFINEsection ofthis chapter. The stream parameter specification must correspond toone of the flash unit products and may be either an absolute or relativevalue. An absolute or relative tolerance value may also be supplied.Note that a default relative tolerance of 0.02 is used if none is given.

EntrainmentEntrainment from one phase to another phase is requested in theFlashDrum Entrainmentwindow which is accessed by clicking the

Entrainment… button on theFlashmain data entry window. TheFrom andTo phases are defined and the quantity entrained is suppliedas a fraction or percent of the donor phase or as an absolute rate ofmaterial. The entrained material is assumed to have the same composi-tion as the donor phase. Since entrainment calculations are performedafter the flash calculations, the resultant products may be different fromthe original flash specifications. Multiple entrainments are permitted.

Temperature or Pressure EstimatesEstimated temperatures or pressures may be supplied in the data entryboxes at the bottom of theFlashmain data entry window. Theseestimates are optional, with a temperature estimate relevant when thefirst specification is the pressure or pressure drop, and a pressureestimate relevant when the first specification is the temperature. Theydo not apply to isothermal flash calculations.

Pseudostream FlowrateForDewandBubble Pointcalculations, an optional liquid and vaporproduct may be defined which corresponds to the equilibrium liquid orequilibrium vapor, respectively. The rate for this pseudostream may besupplied in the data entry field provided on theFlashmain data entrywindow.


Thermodynamic SystemThe thermodynamic system of methods to be used for flash calculationsmay be selected by choosing a method from theThermodynamicSystemdrop-down list box on theFlashmain data entry window.


FLASH WITH SOLIDSGeneral InformationTheFlash with Solidsunit models a flash drum unit operation with asolid product stream. If a solids product stream is to be present, youmust use theFlash with Solidsunit rather than the conventionalFlashunit operation.

Feeds and ProductsA Flash with Solidsunit may have multiple feed streams, in which casethe inlet pressure is assumed to be that of the feed stream with thelowest pressure.

A Flash with Solidsunit typically has four product streams:

● A vapor phase overhead stream from the flash drum section.

● A liquid phase stream from the flash drum section.

● A decanted water/second liquid from the solids separatorsection.

● A solid phase bottom stream from the separator section. Thedefault is complete separation of the solid from the fluid streamand, hence, there is no required input data for this unit.

The bottoms stream from the flash drum section feeding the solidsseparator is internal to theFlash with Solidsunit and is not subject tospecification by the user.

The main data entry window for theFlash with Solidsunit is identicalto that of the ordinary Flash unit except that no specification of productphases by the user is required. The phases for the product streams areautomatically specified by PRO/II and may be reviewed in theFlashProduct Phaseswindow accessible via theProduct Phases… buttonon theFlashmain data entry window.

For further instructions on unit and product specifications, see thedetailed discussions in theFlashsection above (page 9-65, seq.).


FLOWSHEET OPTIMIZERGeneral InformationTheFlowsheet Optimizermaximizes or minimizes an objective function byvarying one or more flowsheet variables while meeting a number of speci-fications. Optionally, you can place constraints on minimum andmaximum values on the flowsheet variables. The objective function maybe an operational criterion, such as maximum recovery or minimum loss,or an economic criterion, such as maximum profit or minimum cost. Inorder to optimize an economic function, you must first include aCalcu-lator in the flowsheet in order to define the profit or cost. Then use theOptimizerto minimize or maximize theCalculatorresult.

Objective FunctionEither you must choose eitherMaximizeor Minimizeas the objectivefunction by selecting the appropriate radio button in the mainOptimizerwindow. Enter the objective function by clicking the linked text stringParameterin theObjective Functionfield to make theParameterwindow available selecting the unit or stream parameter to use as theObjective Function. ThisParameterwindow is similar to theSPECParameterwindow, except that there is no entry allowed for theparameter value and tolerance. TheObjective Functionmay be a singleflowsheet parameter or a mathematical expression that relates twoflowsheet parameters.

VariablesThe optimizer variables (VARYs) are selected by clicking the linked textstring Parameterin theVariablesgrid of theOptimizermain data entrywindow. In theParameterwindow, designate the stream or unit parameterthat will be varied, selecting from the same choices given above for theObjective Function. For unit or stream variables, you must also inputminimum and maximum values. TheSPEC/VARY/DEFINEsection ofthis chapter gives more information on theVARYconcept. The tables inthat section list the flowsheet variables that may be used forSPECsandVARYsfor flowsheet optimizer units.

Variable Step Sizes and LimitsYou may enter limits on the step size for each control variable. Clickthe linked text string default step sizesin the mainOptimizerwindow toopen theVariable Step Sizeswindow. You may enter a relative minimumstep size and/or absolute maximum step size per iteration in this window.You may also enter a non-default step size used to calculate the derivativein this window. The default relative step size depends on theOptimizerscaling option selected (see the section following titledScaling of Opti-


mization Variables). Alternatively, a user-supplied step size can beused in the calculations. The alternative step size may be sized oneither a relative or absolute basis by selecting the appropriate radiobutton.

SpecificationsSPECificationsmay be entered for flowsheet parameters other than thecontrol variables. Click theSpecifications… button on theOptimizermain data entry window to bring up the standardSpecificationswindow. Check theUse Specificationsbox to enable the grid whichcontains the standard specification linked text. Enter the parameters foreachSPECificationby clicking the appropriate text strings in eachspecification. Click the linked text string Parameter, to open theParameterwindow where you can select the unit or stream parameter touse as theSPEC. TheSPECmay be a single flowsheet parameter or amathematical expression that relates two flowsheet parameters. Next,enter the value and the default tolerance for theSPECby clicking onthe appropriate text strings. See theSPEC/VARY/DEFINEsection ofthis chapter for details on the generalizedSPECform.

ConstraintsCONStraintsmay also be entered for flowsheet parameters other thanthe control variables. Constraints limit a variable to a specified range.Click the Constraints… button on the mainOptimizerwindow toopen theConstraintswindow from theSPEC/VARYsystem. Check theUse Constraintsbox to enable the constraint grid. Enter the parametersfor eachCONStraintby clicking the appropriate text strings. Click thehypertext string Parameterto open theParameterwindow where youcan select the unit or stream parameter to use as theCONStraint. Theuse of this window is analogous to theParameterwindow used inselecting theSPECabove. The Minimum Value, Maximum Value, andthe default tolerancevaluesfor theCONStraintare entered by clickingon the appropriate text strings.

Number of Calculation CyclesSeveral options regarding the operation of theOptimizermay be specifiedby clicking the Options… button on theOptimizermain data entrywindow.

The default for the number of calculation cycles is set by PRO/II as 18plus the current number of variables. Alternatively, you may specifythe number of cycles by selecting the appropriate radio button on theOptionswindow.


Scaling of Optimization VariablesBy default,Optimizerscales the optimization variables in the conver-gence algorithm. This scaling can be suppressed by deselecting theUseScalingbox on theOptionswindow.

If scaling is deselected, the default value for the derivative step size thatappears on theVariable Step Sizeswindow is increased from 2 percent to 5percent.

Overall Error in Any VariableThe default value for the overall error in any variable is 10-7. You mayenter a different value for the overall error in the corresponding dataentry field in theOptionswindow.

Minimum Relative Change in Objective FunctionThe default value for theMinimum Relative Change in the ObjectiveFunctionfrom one calculational cycle to the next is 0.005. You may entera different value for the minimum relative change in the box on the Optionswindow.

Selecting the Next Unit Calculated After Control Variable is UpdatedNormally, the first unit operation in the calculation sequence that isaffected by the control variable is the next unit calculated after thecontrol variable is updated. Normally, this is determined automaticallyby the program. However, you must must specify the next unit calcu-lated whenever any of the optimization variables or constraint variablesare thermodynamic parameters. Specify the return unit by selecting thedesired unit from the drop-down list box on theOptionswindow.

Type of Thermodynamic MethodThe PRO/II Optimizer currently supports the use of bothRigorousandLocal Thermodynamic Modelsduring the perturbation steps. Specifythe thermodynamic model by selecting one of the following options intheType of Thermodynamic Modeldrop-down list box:

RigorousThis option specifies that PRO/II will use rigorous thermodynamiccalculation models. This is the default selection.

Local TP ModelThis option specifies that PRO/II will generate local K-value models forT and P derivatives.


Local TPx ModelThis option specifies that PRO/II will generate local K-value models forT, P, and Liquid composition derivatives.

Local TPxy ModelThis option specifies that PRO/II will generate local K-value models forT, P, and Liquid and Vapor composition derivatives.

Advanced OptionsClick the Advanced Options... button to specify additional options fortheOptimizer.

TheOptimizer Advanced Optionsare intended for experienced users ofPRO/II. If you are unsure how these features may apply to your simu-lation, consult SIMSCI Technical Support or refer to thePRO/IIReference Manual.

Special Line Search LogicThis option enables a line search mode method for the optimizationcalculations. By default, this feature isOff. The optionSpecifiedNumber of Trialsin the drop-down list box enables this feature.

When this feature is enabled, you may specify the maximum number ofline search trials for any one optimizer cycle. The number must be apositive integer no greater than 20.

Number of Independent Variables to EliminateYou may specify the number of independent variables to be eliminatedduring the solution of the optimizer calculations.

Start Broyden Updating at CycleYou may specify the optimization cycle at whichBroyden Updatingwill begin. By default, this option isOff. Specify a positive integergreater than 1 to enable this feature.

Derivative AnalysisBy default, this option isOff. SelectOn in the drop-down list toproduce an analysis printout of the derivative step sizes for eachoptimizer cycle; in addition, a modified perturbation step size will besuggested, if appropriate.

Limit Optimization Step SizesBy default, this option isEnabled(Yes). When enabled, this optionlimits the step sizes taken by the optimizer to 30, 60, and 90 percent ofthe upper or lower bounds during optimization cycles 1, 2, and 3,respectively. This is intended as a safety feature to prevent the


Optimizerfrom moving too far, particularly when the derivatives areinaccurate. SelectingNo in the drop-down list box disables this feature.

Separate Shadow Price Output FileOnce the flowsheet optimization has converged and the appropriateoperating conditions have been determined, the shadow prices orLagrange multipliers can be used to assess the sensitivity of theobjective function to the specifications, constraints and bounds.

For maximization problems, a positive shadow price indicates that theconstraint is being pushed against its upper bounds, a negative shadowprice indicates that the lower bound is still active, and a zero shadowprice indicates that the constraint does not affect the solution

By default, printout of these values is disabled (theNoneoption in theSeparate Shadow Price Output Filedrop-down list box).

TheBrief option produces a separate output report with the same filename as the input file (with an .shd extension). This report contains theIDs of the variables, specifications, and constraints, along with theircorresponding shadow prices as part of the standard output report.

TheAll option produces a separate output report with the same filename as the input file (with an .shd extension) containing a detailedsummary of the final Optimizer solution. This summary includes thevalues of the objective function, all variables, specifications, andconstraints, along with the shadow prices for all active bounds andconstraints.

Complete technical details may be found under the topicFlowsheetSolution Algorithmsin thePRO/II Reference Manual.

Print Results for Flowsheet OptimizerThe default is to suppress printing of a convergence report. Click the

Print Options… button on the mainOptimizerwindow to open thePrintOptionswindow. Select the desired printout level from a drop-down list thatincludes the print levelsHistory, Brief, andAll.

By default, no intermediate printout is produced. Print-out levels forintermediate printout of derivative and/or variable values can beselected from a drop-down list which includes the print levelsNone,Print after each cycle,or Print after the final cycle. The program limitsthe options for the variable printout selection such that the level ofprintout is greater than or equal to the derivative printout option.

Select theInclude Convergence Plotscheck box to generate a plot ofthe convergence diagnostics.


HEAT EXCHANGER, LNGGeneral InformationTheLNG Heat Exchangersimulates the exchange of heat between anynumber of hot and cold streams. The exchanger is divided into cellsrepresenting the individual cross-flow elements. Cells are designated asHot, where the streams are cooled or asCold where they are heated.The unit must contain at least one hot cell and one cold cell.

The number of cells is initially defined on theLNG Heat ExchangerConfigurationwindow that appears when the unit is first placed on thePFD. Cells may be added or deleted in the mainLNG Heat Exchangerwindow.

Feeds and ProductsEach cell may have one or more feed streams. If multiple feed streamsare defined, the mixed feed is flashed at the lowest feed streampressure.

A multiphase product from a cell may be separated into streamscontaining one or more phase. The allowable product stream phasesare vapor, liquid, decanted water and mixed (vapor+liquid). A mixedphase product is not allowed with a vapor or a liquid product. Thedecanted water product is also used as the second liquid product phasewith rigorous VLLE calculations.

If a cell has more than one product stream, the phases must be allocatedto the streams in theProduct Phaseswindow. This window is accessedvia the Cell Data… button in the mainLNG Heat Exchangerwindow,then via the Product Phases… button in the now openLNG HeatExchanger Cell Datawindow.

Performance SpecificationsAny cell may have either a duty or an outlet temperature specification.However, at least one cell must remain unspecified. The product streamsfrom all unspecified cells leave the exchanger at the same temperature.

Cell DataThe pressure drop for each cell defaults to zero. Pressure drop valuesare entered in theLNG Heat Exchanger Cell Datawindow. The ther-modynamic system used for the calculations for an individual cell mayalso be changed in this window.


Zones AnalysisZones Analysismay be requested in theLNG Heat Exchanger ZonesAnalysiswindow accessible via theZones Analysis… button on themain data entry window. This feature allows internal temperaturecrossovers and pinch points to be identified by dividing the exchangerinto a number of zones. Warnings are issued if crossovers or pinchpoints are found.

TheZones Analysiscalculations are normally performed when theexchanger is calculated. However, if the exchanger is in a recycle,computation time may be saved by performing the analysis at outputtime.

Zone Analysiswill always be performed at calculation time if requiredby Controller specifications on the LNG heat exchanger.

Print OptionsThePrint Optionswindow is opened via thePrint Options… button onthe main data entry window. A number of different Y versus X plots maybe generated for temperature, duty and UA. The options are:

● Temperature vs. Duty (default)

● UA vs. Duty (default)

● ∆T vs. Temperature (default)

● ∆T vs. Duty

● UA vs. ∆T

● Duty vs. Temperature.

Thermodynamic SystemThe thermodynamic system of methods to be used for LNGHX calcula-tions may be selected by choosing a method from theThermodynamicSystemdrop-down list box on theLNG Heat Exchangermain data entrywindow.

Note: The thermodynamic system used for the calculations for an indi-vidual cell (specified in the LNG Heat Exchanger Cell data window)overrides this thermodynamic system for specific cells.


HEAT EXCHANGER, RIGOROUSGeneral InformationTheRigorous Heat Exchangersimulates the operation of an existingheat exchanger. The geometry of the unit has to be defined and the unitis rated to determine the duty, exit temperatures, and pressure drops.

The exchanger duty, or one of the exit temperatures, may be defined. Inthis case, the fouling resistance is calculated.

Feeds and ProductsEach side of the exchanger may have one or more feed streams. Ifmultiple feed streams are defined, the mixed feed is flashed at thelowest feed stream pressure.

A multiphase product from the exchanger may be separated intostreams containing one or more phase. The allowable product streamphases are vapor, liquid, decanted water and mixed (vapor+liquid). Amixed phase product is not allowed with a vapor or a liquid product.The decanted water product is also used as the second liquid productphase with rigorous VLLE calculations.

If either side has more than one product stream, the phases must beallocated to the streams in theProduct Phaseswindow accessed viathe Product Phases… button in theRigorous Heat Exchanger–Feedsand Products Datawindow.

Calculation TypeThe calculation type is selected from a drop down list in theRigorousHeat Exchangerwindow. The available options are:

Rating: Determine the heat transferred with the defined area andfouling factors. The default.

Fixed Duty: Determine the fouling factors and exit temperatures from thedefined duty.

Tube Outlet Temperature: Determine the duty, fouling factors, and shellexit temperature from the defined tube outlet temperature.

Shell Outlet Temperature: Determine the duty, fouling factors, and tubeexit temperature from the defined shell outlet temperature.

If the selected calculation type is notRating, a value must be suppliedfor the duty or exit temperature as appropriate.


Exchangers Attached to ColumnsExchangers may be attached to any tray of a column for which a duty isdefined, either heating or cooling. To attach an exchanger to a column,double-click the Attach to Column… button for the shell or tube sideon theRigorous Heat Exchanger–Feed and Products Datawindow andsupply the appropriate information in the window provided.

A column internal stream is considered as one side of the exchangerand a process stream is defined for the other side.

Attached exchangers may be used to represent the condenser or reboilerfor the column, a pumparound, or side heater/cooler. For side heatersand coolers, the column stream may be the vapor or liquid from the trayto which the exchanger is attached, the vapor from the tray below, orthe liquid from the tray above.

If the Calculation Typedoes not fix the exchanger duty or one of theoutlet temperatures, the exchanger duty will be fixed by the columnheater or cooler. It is generally best to allow the column operation todetermine the duty required to meet the defined performance. If theduty is fixed by an exchanger specification, it is considered a “fixed”duty for the column calculations.

Overall ConfigurationThe overall configuration is defined in theRigorous Heat Exchangerwindow by entering one or more of the configuration parameters:

● Number of Tubes/Shell

● Area/Shell

● Shell Inside Diameter

A value for at least one of these parameters must be supplied. If any ofthese parameters is missing, it will be calculated from the others.

Configuration DataThe configuration details are defined in theRigorous Heat ExchangerConfiguration Datawindow accessible via theConfiguration… buttonon the main data entry window. All data in this window have defaultvalues:

Number of Shells in Series: This is the number of identical shellsconnected in series in the unit. Both shell and tube sides are consideredto be piped in series. The default is 1 shell.

Number of Shells in Parallel: This is the number of identical shellsconnected in parallel in the unit. Both shell and tube sides are consid-ered to be piped in parallel. The default is 1 shell.


Number of Tube Passes/Shell: This can be any integer value between 1 and16. The default is 2. Odd numbered values are allowed, but are notrecommended.

Orientation: The exchanger orientation is selected from the drop-downlist as eitherHorizontalor Vertical. The default isHorizontal.

Configuration: The direction of fluid flow is selected from thedrop-down list as eitherCountercurrentor Cocurrent. The default isCountercurrent.

TEMA Type: The three characters for the TEMA type (front, shell andrear of the exchanger) are selected separately from drop down lists.The default is AES.

Tube DataDetails of the exchanger tubes are entered in theRigorous HeatExchanger Tube Datawindow which is accessed with theTubes…icon on the main data entry window. All tube data have default values.

Length: The nominal tube length includes the thickness of both tube-sheets. For U-tubes, it includes the thickness of the tubesheet and thelast baffle. The length defaults to 20 ft (6.1 m).

Outside Diameter: The tube outside diameter defaults to 0.75 inches(19.05 mm).

Thickness: The tube thickness may be defined as:Inside DiameterWall ThicknessBWG

Bare tubes default to an inside diameter of 0.58402 inches (14.834 mm).Finned tubes default to an inside diameter of 0.49598 inches (12.573 mm).

Pitch: The center-to-center distance between tubes defaults to 1.0 inch(25.4 mm).

Pattern: The tube pattern is selected from the drop down list. Theoptions areTriangular–30 Degrees,Square–90 Degrees (default),Rotated Triangular–60 Degrees, andRotated Square– 45 Degrees.

Sheet Thickness: The tubesheet thickness is calculated if it is not supplied.

Fin DataThe default is not to have finned tubes. If fins are specified, the surfacearea may be entered directly or calculated from the fin data.

Extended Surface Area: This is the total surface area of the tubesincluding the finned and bare surface areas. A value entered hereoverrides the calculated area.


Fins/Inch: This is the number of fins per inch of tube length.(Default is 19.

Thickness: The fin thickness defaults to a value in inches equal to0.5/(Fins per Inch).

Height Above Root: The fin height above the root defaults to a value equal to(Tube Outside Diameter - Root Diameter)/2

Root Diameter: The root diameter is the tube diameter at the base of thefins and it defaults to 0.625 inches.

Baffle DataDetails of the exchanger baffles are entered in theRigorous HeatExchanger Baffle Datawindow accessible via theBaffles… icon onthe main data entry window. All baffle data have default values.

Baffle Type: The type is selected from the drop down list. The optionsareNo Baffles, Single(default),Single Baffles - No Tubes in WindowandDouble.

Baffle Geometry Data: The bafflecut is the height of the window dividedby the shell inside diameter and it defaults to 0.2. Alternatively, theNetFree Area Ratiomay be entered instead. This is the area of the windowdivided by the cross-sectional area of the shell.

Center Spacing: If a value is not supplied, the baffle center-to-centerspacing is calculated by default to be 0.2*(Shell Inside Diameter). Anyvalue entered will be ignored if bothInlet SpacingandOutlet Spacingare defined and the value will be calculated to provide even spacing.

Inlet Spacing: This is the center-to-center spacing between thetubesheet and the inlet baffle. If the inlet spacing is not supplied, it iscalculated to meet the center spacing or, if no center spacing is defined,it defaults to 5 inches (133 mm) for bare tubes or 3 inches (88 mm) forfinned tubes.

Outlet Spacing: This is the center-to-center spacing between thetubesheet and the outlet baffle. If the outlet spacing is not supplied, itis calculated to meet the center spacing or, if no center spacing isdefined, it defaults to 5 inches (133 mm) for bare tubes or 3 inches (88mm) for finned tubes.

Thickness: If a value is not supplied, the baffle thickness defaults to0.1875 inches (4.763 mm).

Number of Sealing Strips: This is the number of pairs of sealing strips percross-flow pass. It defaults to zero.


Film Coefficient DataFilm Coefficient Data are entered in theRigorous Heat Exchanger FilmCoefficient Datawindow accessible via theFilm Coefficients… buttonon the main data entry window. These data provide adjustment factorsand override values for the heat transfer parameters.

Overall U-value Estimate: This is the initial value for the heat transfercoefficient used in the calculation. The default is 50 Btu/hr·ft2·°F(244.1 kCal/hr·m2·°C or 1021.9 kJ/hr·m2·K).

Overall U-value Scale Factor: This is a multiplier which is applied to allcalculated heat transfer coefficients. It can be used in order to matchplant data more closely. It defaults to 1.0.

Tubeside and Shellside DataThe following items have separate entries for each side of the heatexchanger.

Scale Factor: This is a multiplier which is applied to the film coeffi-cient for the specified side of the exchanger. It defaults to 1.0.

Coefficient: If a value is entered, it overrides the calculated film coeffi-cient for the specified side.

Fouling Resistance: Thermal fouling resistance defaults to 0.002ft2·hr·°F/Btu (0.00041 m2·hr·°C/kCal or 0.00010 m2·hr·K/kJ). If a dutyor exit temperature is specified, the fouling will be calculated.

Fouling Thickness: The thickness of the fouling layer may be entered tomodel its effect on the pressure drop. The default value is zero.

Material DataTube and shell material property data are entered in theRigorous HeatExchanger Material Datawindow accessible via theMaterials… iconon the main data entry window.

The default material is carbon steel. A different material may beselected from a drop-down list which shows the materials in the library.Individual properties of the selected material may be overridden.

Alternatively, the user may selectUser-added Materialfrom the listand then supply the name and properties of the material.

The list of materials in the library is tabulated below.


Heat Exchanger Materials of Construction

Material Density Conductivity

Description Label lb/ft 3 kkg/m 3 Btu/hr �ft �°F kCal/hr �m�°C W/m�K

Carbon Steel CARB STL 490.8 7862 30.0 44.6 51.9

Carbon-moly Steel 0.1C, 0.5Mo CARB MLY 493.2 7900 29.0 43.2 50.2

Chrome-moly Steel 1.0Cr, 0.5Mo CHRM MLY 490.1 7851 27.0 40.2 46.7

Low Chrome Steel 2.25Cr, 1.0Mo LOW CHRM 487.0 7801 25.0 37.2 43.3

Medium Chrome Steel 5.0Cr, 1.0Mo MED CHRM 480.7 7700 21.0 31.2 36.3

Straight Chrome Steel 12Cr STR CHRM 487.0 7801 14.0 20.8 24.2

304 Stainless Steel 18Cr, 8Ni 304 S.S. 501.1 8027 9.3 13.8 16.1




Aluminum 1060 H14 A1060H14 170.0 2723 128.3 190.9 222.1

Aluminum 1100 Annealed A1100 AN 169.3 2712 128.3 190.9 222.1

Aluminum 3003 H14 Annealed A3003H14 171.1 2741 111.0 165.2 192.1

Aluminum 3003 H25 Annealed A3003H25 171.1 2741 111.0 165.2 193.1

Aluminum 6061 T4 Tempered A6061 T4 169.3 2712 95.0 141.4 164.4

Aluminum 6061 T6 Tempered A6061 T6 169.3 2712 95.0 141.4 164.4

Copper COPPER 556.4 8913 225.0 334.2 389.4

Arsenical Copper AS COPPER 560.0 8970 187.0 278.3 323.6

Copper Nickel 90/10 CUNI9010 559.0 8954 26.0 38.7 45.0


Copper Nickel 70.30 CUNI7030 585.0 9371 17.0 25.3 29.4


Red Brass 85Cu, 15Zn RED BRAS 546.0 8746 92.0 136.9 159.2

Admiralty Brass 71Cr, 28Zn, 1Sn ADMRALTY 531.0 8506 64.0 95.2 110.8

Commercial Brass 55Cu, 34Zn COM BRAS 529.0 8474 67.0 99.7 116.0

Muntz Metal 60Cu, 40Zn MUNTZ 524.0 8394 71.0 105.7 122.9

Aluminum Bronze 93Cu, 5Al AL BRONZ 510.0 8169 48.0 71.4 83.1

Aluminum Brass 78Cu, 2Al AL BRASS 520.0 8330 58.0 86.3 100.4


Heat Exchanger Materials of Construction

Material Density Conductivity

Description Label lb/ft 3 kkg/m 3 Btu/hr �ft �°F kCal/hr �m�°C W/m�K

Nickel Annealed NICKEL 556.4 8913 45.2 67.3 78.2

Low Carbon Nickel Annealed L CRB NI 554.7 8885 35.0 52.1 60.6

Monel Nickel 70Ni, 30Cu MONEL NI 551.2 8829 14.5 21.6 25.1

Inconel 600 76Ni, 16Cr, 8Fe INCNL600 525.3 8414 8.7 12.9 15.0

Titanium Grade 2 TITANIUM 281.6 4511 9.5 14.1 16.4

Pressure Drop DataPressure drop data are entered in theRigorous Heat ExchangerPressure Drop Datawindow accessible via thePressure Drop… iconon the main data entry window. These data provide adjustment factorsand override calculated values for the pressure drops. All data may bedefaulted.

By default the pressure drops are calculated for each side of theexchanger. A scale factor may be applied to the calculated value foreither side or the pressure drops may be overridden.

DP Scale Factor: This is a multiplier which is applied to the pressuredrop for the specified side of the exchanger. It defaults to 1.0.

DP / Shell: If a value is entered, the pressure drop per shell overridesthe calculated pressure drop for the specified side.

DP / Unit: If a value is entered, the pressure drop for the exchanger unitoverrides the calculated pressure drop for the specified side.

Shellside Pressure Drop Method: The method may be selected fromBell(default) for the Bell-Delaware method orStreamfor the streamanalysis technique.

Print OptionsAdditional output reports are selected in theRigorous Heat ExchangerPrint Optionswindow accessible via thePrint Options… icon on themain data entry window.

Extended: By default, a standard TEMA data sheet is produced for theexchanger. Checking theExtendedcheck box produces an additionaldata sheet with information about stream properties, heat exchangerconfiguration and hydrodynamics.


Zones: Checking theZonescheck box produces an additional tableshowing the phase and zone boundaries used to calculate the duty-averaged log-mean-temperature difference.

Zones Plot: Checking theZones Plotcheck box produces a plotshowing the phase and zone boundaries used to calculate the duty-averaged log-mean-temperature difference.

Nozzle DataThe default nozzle type and sizes can be overridden in theRigorousHeat Exchanger Nozzle Datawindow accessible via theNozzles…icon on the main data entry window.

The default is to use conventional nozzles with calculated insidediameters. Nozzle data only affects the calculated pressure drop in theexchanger.

Use Tube Side Nozzle or Use Shell Side Nozzle: If either check box isunchecked, the nozzle pressure drop will not be calculated for that sideof the exchanger.

Inside Diameter: The calculated diameters may be overridden. TheInletand/orOutletdiameter may be entered.

Use Annular Shell Side Nozzles: If this box is checked, the pressure dropwill be calculated for annular rather than conventional nozzles. In thiscase, the Enter Data… button must be clicked to open theAnnularNozzle Datawindow where the nozzle details must be entered. Therequired data are:

● Inlet and outlet annular passage lengths

● Inlet and outlet groove areas

● Inlet and outlet annular-shell wall clearances

Thermodynamic SystemThe thermodynamic system of methods to be used for each side of therigorous heat exchanger may be selected by choosing a method fromtheThermodynamic Systemdrop-down list box on theRigorous HeatExchangermain data entry window.


HEAT EXCHANGER, SIMPLEGeneral InformationTheSimple Heat Exchangermay be used to heat or cool a singleprocess stream, exchange heat between two process streams, orexchange heatbetween a process stream and a utility stream. Rigorouscalculations may be performed for VLLE systems. It is also possible toattach an exchanger to any tray of a distillation column and exchange heatbetween a process stream and a column internal stream, either liquid orvapor.

Feeds and ProductsFor reference, streams and products are grouped according to the sideof the exchanger as “hot” or “cold”, where the feed stream(s) on the hotside are cooled and the feed stream(s) on the cold side are heated.Multiple processfeed streams are permitted, with the lowest streampressure used as the inlet pressure.

The product from each side of an exchanger may be phase separated asdesired into multiple product streams, where products may be liquid,vapor, mixed phase, and decanted water (hydrocarbon systems only).The “water” product stream may also be used to represent a secondliquid phase for systems in which rigorous modeling of VLLE thermo-dynamics is considered.

Feed and product streams are accessed via theHeat Exchanger ProcessStreamswindow which is opened by clicking theProcess Stream…

button on theHeat Exchangermain data entry window. The productphase condition for units with one product stream is automatically setby PRO/II. For simple heat exchangers with two or more productstreams from a given side, the product phasesmustbe specified in theProduct Phaseswindow accessible by clicking theProduct Phases…button on theHeat Exchanger Process Streamswindow.


Utility StreamsFor simple heat exchangers with one process side, a hot or cold utilitystream may be defined. The required utility rate for the specified heattransfer is always computed. Utility streams may be specified by clickingthe Utility Stream… button on theHeat Exchangermain data entrywindow to access the appropriate hot or cold utility window.


Cold utility streams are supplied in theHeat Exchanger Cold Side Utilitywindow. Options are:

Water: Temperature in and out must be supplied. Sensible heat transfer only.

Air: Temperature in and out must be supplied. Sensible heat transfer only.

Refrigerant: A designated component is vaporized at its saturationpressureor temperature. Latent heat transfer only.

Hot utility streams are supplied in theHeat Exchanger Hot Side Utilitywindow. Options are:

Steam: Steam is condensed at its saturation temperatureor pressure.Latent heat transfer only.

Heating Medium: A designated component is condensed at its saturationtemperatureor pressure. Latent heat transfer only.

Configuration DataConfiguration data are supplied in theHeat Exchanger ConfigurationData window, which is accessed by theConfiguration… button on themain data entry window. These data only apply to exchangers withtwosides and are optional for all exchangers for which aPerformanceSpecificationis provided (see below).

Flow Direction: Countercurrent or cocurrent. Default is countercurrent.

Tube and Shell Passes: When supplied, an N - 2N configuration isalwaysassumed, where the number of shell passes is twice the number of tubepasses. The “FT” LMTD correction factor is computed, based on acorrelation for N - 2N exchangers. Default is one tube and one shellpass, i.e., true countercurrent flow.

FT Factor: The LMTD correction factor for the exchanger. Note thatthis entry is mutually exclusive with theTube and Shell Passes.

Performance SpecificationsExchanger performance is specified in theHeat Exchanger Specifica-tionswindow, which is accessed with theSpecifications… button onthe main data entry window. Exchanger performance may be specifiedin a varity of ways:

Outlet Temperature: Temperature out for hot or cold process fluid.

Temperature Approach (Two-sided exchangers only)● HOCO: Hot out minus cold out.

● HOCI: Hot out minus cold in.

● HICO: Hot in minus cold out.


● Minimum: Smaller of HOCI and HICO.

● Minimum Internal Temperature Approach (MITA): Minimuminternal approach based on a zones analysis for the exchanger.

Duty: Overall heat transfer duty for the exchanger.

Outlet Stream Liquid Fraction: The liquid fraction for the hot or cold sideexit fluid where 0.0 indicates bubble point and 1.0 indicates dew pointconditions.

Degrees of Superheat: The degrees of superheat (above the dew point) forthe hot or cold side exit fluid.

Degrees of Subcooling: The degrees of subcooling (below the bubblepoint) for the hot or cold side exit fluid.

Overall Heat Transfer Coefficient (U): The area is calculated from this entrywhen not supplied. When bothU andAreaare given, the heat transferis computed to satisfy theU*Area and no other performance specifica-tions are allowed for the exchanger.

Exchanger Area: The overall heat transfer coefficient for the exchanger iscalculated from this entry when not supplied. When bothU andAreaare given, the heat transfer is computed to satisfy theU*Area and noother performance specifications are allowed for the exchanger.

Lumped UA Specification: The product of overall heat transfer coefficientand exchanger area may be supplied directly.

Individual U and Area Specification: Individual values for the overall heattransfer coefficient and exchanger area may be supplied directly.

Maximum U *Area: A maximumU*Area may be supplied to limit theheat transfer otherwise determined by a performance specification ifnecessary. This specification is not allowed when either aLumped UAspecification or the exchanger overallU and Areahave been suppliedindividually.

Zones AnalysisZones analysis is requested by clicking theZones Analysis… buttonon the main data entry window. The duty-weighted LMTD may becomputed for exchangers in which phase changes occur by dividing theexchanger into at least five zones of equal duty. More zones may berequested as desired. Zones analysis is automatically performed forexchangers withMITA specifications. For other types of specificationsthe zones analysis may be performed during exchanger calculations orat the completion of all calculations, as requested. Warning messagesare given for temperature crossovers.


Exchangers Attached to ColumnsExchangers may be attached to any tray of a column for which a duty isdefined, either cooling or heating. To attach an exchanger to a column,click the Attach to Column… button on the main data entry windowand supply the appropriate information in the window provided.

An internal column stream is considered as one side of the exchanger;a process stream or utility stream defined for the exchanger is the otherside. Note that for utility streams, the dutymust bedetermined by thecolumn calculations.

Attached exchangers may be used to represent the condenser or reboilerfor the column, a pumparound cooler, or a side heater or cooler. Forside heaters and coolers, the column stream may be: the vapor or liquidfrom the tray to which the exchanger is attached, the vapor from thetray below the tray to which the exchanger is attached, or the liquidfrom the tray above the tray to which the exchanger is attached.

It is generally best to let the exchanger duty be determined in thecolumn operation to meet a desired separation criterion. If the duty isdefined by a performance specification for the exchanger it is consid-ered a “fixed” duty for the column calculations.

Thermodynamic SystemThe thermodynamic system of methods to be used for each side of thesimple heat exchanger may be selected by choosing a method from theThermodynamic Systemdrop-down list box on theHeat Exchangermain data entry window.


HEATING/COOLING CURVESGeneral InformationTheHeating/Cooling Curveutility module develops heating or coolingcurves for any stream in the flowsheet. The tables are a composite ofequilibrium flashes, and present the data typically required for thedesign of heat transfer equipment. Curves may be generated by usingequal temperature increments or equal duty increments. Additionalpoints are included when phase boundaries are crossed.

For theFlash, Heat Exchanger, andColumnunit operations, a conven-ient means is provided to retrieve the streams involved in heat transferand generate curves based on the actual duties for the units. For otherflowsheet streams, you may define the desired temperature or dutyranges for the curves.

In addition to the standard thermal properties, additional properties maybe requested for the reports. These properties include physical, critical,thermodynamic, transport, and petroleum properties.

Heating/Cooling Curves for Flowsheet StreamsA drop-down list box is used to retrieve flowsheet streams for whichcurves are desired in theHeating/Cooling Curvesmain data entrywindow. After selecting a stream, clickEnter Data to open theHeating/Cooling Curve for Flowsheet Streamwindow. This window isused to select the boundaries for the curves, type of curves, number ofpoints for the curves, and the report options.

A combination of two specifications is used to define the type and bounda-ries for the curves. Curves may be at equal temperature increments, equalduty increments, or may be the dew point or bubble point curve for thefluid. Dew and bubble points may be calculated at defined pressures or atdefined temperatures. When the temperature and pressure ranges are definedfor a curve, the resultant points are always at equal temperature/pressureintervals. When a temperature, pressure, or duty increment is defined for acurve, the starting point is always taken to be the current stream conditions.

The number of points for the curves may be selected on this form byreplacing the default number of 11. When phase boundaries arecrossed, additional points are added to the report which represent thetransition points.

A check box may be used to select printout of liquid activity coeffi-cients, vapor fugacity coefficients, and Poynting correction factors forthermodynamic systems based on liquid activity coefficients. The equi-


librium K-values for the components may also be selected for printoutwith a check box.

Heating/Cooling Curves for Unit OperationsA drop-down list box is provided for selection of unit operations forwhich curves are desired in theHeating/Cooling Curvesmain dataentry window. Units for which curves may be requested include theFlash, Heat Exchanger, andColumn.

To select the options for the unit:➤ Click Enter Data adjacent to the unit name.

The appropriate window for the unit operation appears for selection of curveoptions. In each case, the user may specify printout options for liquid activitycoefficients, vapor fugacities, and Poynting corrections for thermodynamicsystems based on liquid activity coefficients. The equilibrium K-values forthe components may also be selected for printout.

Heating/Cooling Curves for Flash UnitsCheck boxes and radio buttons are used on theHeating/Cooling Curvesfor Flash Drumwindow to select the options for the curves. Thetemperature and pressure range is predefined as the inlet and outletconditions for theFlash.

The curves may be defined asisothermal, i.e., at equal temperatureincrements, or asadiabatic, i.e., at equal duty increments. The numberof points for the curves may be selected on this form by replacing thedefault number of 11. When phase boundaries are crossed, additionalpoints are added to the report which represent the transition points.

Heating/Cooling Curves for Heat ExchangersCheck boxes and radio buttons are used on theHeating/Cooling Curvesfor Heat Exchangerswindow to select the options for the curves. Thetemperature and pressure range is predefined as the inlet and outletconditions for each side of theHeat Exchanger.

The curves may be defined asisothermal, i.e., at equal temperatureincrements, or asadiabatic, i.e., at equal duty increments. The numberof points for the curves may be selected on this form by replacing thedefault number of 11. When phase boundaries are crossed, additionalpoints are added to the report which represent the transition points.

Heating/Cooling Curves for ColumnsColumn streams are selected in a drop-down list box on theHeating/Cooling Curves for Column Internal Streamswindow.Streams available include the condenser and reboiler feeds, and feeds to


trays with duties such as side reboilers and pumparound coolers. Thecurves may be defined asisothermal, i.e., at equal temperature andpressure increments, or asadiabatic, i.e., at equal enthalpy and pressureincrements. The temperature and duty ranges are predefined as the unitoperating conditions. A pressure range may be added to pumparoundstreams to simulate the effects of pumping.

The number of points for the curves may be selected on this form byreplacing the default number of 11. When phase boundaries arecrossed, additional points are added to the report which represent thetransition points.

Standard ReportsStandard reports include the data in the table below:

Total Feed Vapor Liquid

Temperature X

Pressure X

Molar Flow X X

Enthalpy X X X

Weight Flow X X

Molar Entropy X X X

Additional Stream PropertiesThese properties are requested by clickingReport Additional StreamProperties on the Heating/Cooling Curve main data entry window.These properties are reported in addition to the standard reports for allcurves selected for the Heating/Cooling Curve.


Additional Stream Properties Reports

Additional reports include the data tabulated below:

Total Feed Vapor Liquid

Molecular Weight X X

Actual Density X X

Volumetric Flow X X

Compressibility Factor X

Specific Gravity X

Flowing Entropy X X X

Enthalpy (unit basis) X X X

Latent Heat X X

Heat Capacity X X

Viscosity X X

Thermal Conductivity X X

Surface Tension X

Critical Temperature X X

Critical Pressure X X

Critical Compressibility X X

API Gravity X X

Watson K Factor X X

Molar Average Boiling Point X X

PlotsRefer toChapter 11, Printing and Plotting, for more information aboutgenerating graphical plots of Heating/Cooling Curve results.

Thermodynamic SystemYou may select the thermodynamic system of methods to be used forheating/cooling curves calculations by choosing a method from theThermodynamic Systemdrop-down list box on theHeating/CoolingCurvesmain data entry window.


MIXERGeneral InformationTheMixer unit combines two or more streams into a single productstream. The outlet pressure may be specified if desired. The outlettemperature and phase condition are always determined with anadiabatic flash from the feed conditions. This unit supports both VLEand VLLE calculations.

Feeds and ProductsThe inlet pressure is assumed to be the lowest feed pressure. There isno limit on the number of feed streams to a mixer.

Only oneproduct stream is allowed for a mixer. PRO/II automaticallysets the temperature and phase condition for the product. If phase sepa-ration of the product is desired, a separate flash unit must be used forthis purpose.

Outlet Pressure SpecificationThe pressure specification for the mixer product is selected with theappropriate radio button on theMixer window:

● Pressure drop from feed conditions,or

● Outlet pressure

If neither entry is supplied, the default is a pressure drop of zero.

Thermodynamic SystemThe thermodynamic system of methods to be used for mixer calcula-tions may be selected by choosing a method from theThermodynamicSystemdrop-down list box on theMixer main data entry window.


MULTIVARIABLE CONTROLLERGeneral InformationTheMultivariable Controller(MVC) is an expanded form of theController and simulates two or more feedback process controllers. TheMVC is capable of adjusting an unlimited number of upstreamvariables to reach the same number of specified objectives. Each of theSPECificationsmay be a stream flowrate or property, a unit operatingcondition, or aCalculator result. The control variables may be streamand unit operation conditions, thermodynamic parameters, andCalcu-lator results that are otherwise at fixed values in the flowsheet.

For theMultivariable Controller, the number of variables must equalthe number of specifications. The linked text above theSpecificationsgrid in theMultivariable Controllermain data entry window indicateswhether the current number of specifications equals the number ofvariables. If they are unequal, the hypertext string “does not equal”will appear in red.

SpecificationsEstablish theSPECificationsby clicking the appropriate linked text intheSpecificationgrid of theMultivariable Controllerwindow. MVCSPECificationsare established in the same manner as for the simpleControllerSPECifications. See theSPEC/VARY/DEFINEsection of thischapter for further details on the generalizedSPECform.

VariablesEstablish the control variables (VARYs) by clicking the linked textstringParameterin theVariablegrid of theMultivariable Controllerwindow. MVC VARYs are established in exactly the same manner assimple ControllerVARYs. See theSPEC/VARY/DEFINEsection of thischapter for more information on theVARYconcept. Tables are alsogiven in that section listing the flowsheet variables that may be used forSPECs and VARYs for multivariable controller units.

Variable Limits and Step SizesYou may input limits for the each control variable, if desired. Variablelimits and steps sizes for MVC are established in exactly the samemanner as simpleController limits and step sizes. In contrast to thesimpleController which has a default percent change of 2.0% of theinitial control variable for the second iteration, the MVC has a defaultpercent change of 10.0%.


Optional Variable ScalingSelect the UseUser-defined Variable Scalingcheck box on theVariableLimits window to enable a linear formula for scaling the variable. Inorder to access this window, click on the default limitslinked text in theVariablesfield in theMultivariable Controllerwindow. After you haveenabled theScaled Variableformula, the default limitslinked text willchange to read user-defined limits.

Defaults for the scaled variable data are displayed on theOptionswindow which can be accessed through theMVC Options button ontheMultivariable Controller window. The same initial value, stepsizes and tolerances are applied to all scaled parameters in the MVC.You may enter your own values here to replace the default values 100,10, and 10-5 respectively.

Number of Calculation CyclesYou may access several options for the operation of theMVC throughtheMVC Optionsbutton on theMultivariable Controllerwindow.

The default for the number of calculation cycles is calculated by theprogram as 18 plus the current number of variables. Alternatively, youmay specify the number of cycles by selecting the appropriate radiobutton on theOptionswindow.

By default, the simulation will stop if any variable exceeds themaximum or minimum limits. You may select theContinue Calcula-tions if Any Variable Exceeds the Limitscheck box to continue calcula-tions using the limiting value if the limit is exceeded.

Selecting the Next Unit Calculated After Control Variable is UpdatedNormally, the first unit operation in the calculation sequence affectedby the control variable is the next unit calculated after the controlvariable is updated. Normally, the calculation sequence is determinedautomatically by PRO/II. However, you must supply a calculationsequence youself whenever any of the control variables are thermody-namic parameters. You may specify the return unit by choosing a unitfrom the drop-down list box on theOptionswindow.

Print Results for Multivariable ControllerThe default is to suppress printing of a convergence report. The PrintOptions window allows you to override the default. This window isaccessed by clicking thePrint Options button on the MultivariableController window or be selectingOutput/Report Format/Unit Opera-tions from the menu. A convergence summary can be printed after thelast cycle or after every cycle by selecting the appropriate radio button.


Select theInclude Convergence Diagnosticscheck box to generate aplot of the convergence diagnostics.Select theInclude Convergence Diagnosticscheck box to generate aplot of the convergence diagnostics.

Non-Convergence of Multivariable ControllersSee theController section of this chapter for a discussion of conver-gence techniques used in theMultivariable Controllercalculations.

Controllers and Recycle LoopsSee theController section of this chapter for a discussion of recycleloops.


PHASE ENVELOPEGeneral InformationThePhase Envelopeutility module generates phase envelopes for multi-component streams using the Soave-Redlich-Kwong or Peng-Robinsonequations of state. The module is not available for other thermodynamicsystems.

Phase envelope generation is performed after the completion offlowsheet calculations and has no effect on flowsheet convergence. Forsystems with non-condensible gases such as hydrogen, helium, andnitrogen it may not be possible to converge bubble point calculationsand results should be reviewed carefully.

Selection of StreamsYou may select feed and product streams from any of the unit opera-tions in the flowsheet for phase envelope generation. Up to fiveflowsheet streams may be selected using drop-down list boxes in thePhase Envelopemain data entry window.

You may optionally supply a liquid mole fraction for any of the selectedflowsheet streams to generate a curve at a constant liquid mole fraction.This option is useful for generating liquid fraction curves to be superim-posed on the phase envelope. Normally, you would first select a flowsheetstream with no liquid fraction entry to generate the phase envelope,followed by one or more selections with specified liquid fraction entries togenerate a family of curves. It is not permissible to duplicate the samestream with the same liquid mole fraction in a single phase envelope.

Plot OptionsSelect a plot option for the phase envelope in thePhase Envelope PlotOptionswindow which you can access by clickingPlot Options onthePhase Envelopemain data entry window.

For each selected stream, a default descriptive label is provided in thiswindow. The default label will contain the stream name and an L/Fvalue if specified. You may modify each label. Duplicate labels arenot allowed. An example default stream label with a specified L/F is:“S100 - L/F= 0.9".

A drop-down list box contains plot options as follows:

None The default

Individual Individual generates a plot with only the stream selected.


Comparison All streams with theComparisonoption are plotted on thesame graph. TheComparisonoption is useful for plotting a streamphase envelope with superimposed curves of constant liquid molefraction. When you select theComparisonoption for a stream, you willbe prompted to provide a comparison plot symbol to label the datapoints for the generated curve. The symbol may be an integer numberin the range one through nine. If you do not provide a symbol is notprovided for the comparison plot, the next available integer betweenone and nine is used

Individual and Comparison The Individual and Comparisonoptionperforms both theIndividual andComparisonoptions for a stream.

Thermodynamic SystemSelect the thermodynamic system of methods to be used forPhaseEnvelopecalculations by choosing a method from theThermodynamicSystemdrop-down list box on thePhase Envelopemain data entrywindow.


PIPEGeneral InformationThePipeunit is used to model single or multi-phase pressure drops inpipes and/or fittings which connect unit operations. This unit may beused in two modes:Rating Modewhere the pressure drop is computedbased on a specified line diameter, andDesign Modewhere the linediameter is calculated to meet a specified pressure drop and/ or velocitycriteria. Numerous algorithms are provided for the pressure drop calcu-lations to model a variety of piping applications. A rigorous heatbalance may also be performed for the calculations, in which heat istransferred through the pipe to or from an ambient medium, or a duty isuniformly applied to the length of the pipe. The phase equilibrium isdetermined for the product and it may be separated into streamsaccording to the phases. Both VLE and VLLE calculations aresupported by this unit.

Feeds and ProductsA pipe operation may have multiple feed streams, in which case theinlet pressure is assumed to be the lowest feed stream pressure.

A pipe may have one or more product streams. The product phasecondition for pipe operations withoneproduct is automatically set byPRO/II. For pipe units with two or more product streams, the productphasesmustbe specified in theProduct Phaseswindow which isaccessed by clicking theProduct Phases… button on thePipemaindata entry window.

Product phases allowable include: vapor, liquid, decanted water, heavyliquid, and mixed phase (vapor plus liquid). Mixed phase is mutuallyexclusive with vapor and liquid products and is not allowed when fourproduct streams are specified. It is important to note that where twoliquid phases are present in multiphase calculations, all pressure dropmethods consider only a single liquid phase which has fluid propertiesthat are an average of the properties for the two liquid phases.

Calculation TypeThe Calculation Type may be selected with the radio buttons providedon thePipemain data entry window. Options are as follows:

● Fixed Line Diameter - Forward Calculation(default)

● Fixed Line Diameter - Backward Calculation

● Line Sizing - Forward Calculation


Backward calculations determine the pressure drop in a backward, orreverse direction, starting from the pipe outlet conditions. The pipeinlet conditions are defined by the results of the backward calculations.The line sizing option may be used fordesignmode, in which case thediameter of the pipe is determined to meet a specified design criterion.

Note: Pipe calculations require liquid and vapor viscosities, and, fortwo phase flow, the liquid surface tension. Therefore, the thermody-namic system chosen for the calculations must provide these properties.

Corrective Action for Calculation FailuresThe Continuetext string on thePipemain data entry window may beclicked to select the corrective action for certain types of calculationfailures. The default option of Continueuses the best available solutionor sets a negative computed outlet pressure to a small value and allowsthe flowsheet calculations to continue. For line sizing calculationfailures, the line diameter which most closely satisfies the designcriteria is selected and flowsheet calculations continue. A maximum ofthree consecutive failures is allowed for pipe units in recycle loops.

The Stopoption terminates all flowsheet calculations whenever the pipeunit fails to reach a solution, or a negative outlet pressure isencountered.

Pressure Drop MethodSelect the pressure drop method in thePipe Pressure Drop Methodwindow accessible via thePressure Drop Method… icon on thePipemain data entry window. The pressure drop method is selected with thedrop-down list box in this window, and includes the following methods:Beggs-Brill-Moody (BBM), Beggs-Brill-Moody with Palmer Correc-tion (BBP), Olimens (OLIMENS), Dukler-Eaton-Flanigan (DEF),Mukherjee-Brill (MB), Gray (GRAY), and Hagedorn-Brown (HB).Beggs-Brill-Moody is selected as the default correlation.

An optional estimated pressure drop may be supplied in this window toreduce the computing time.

The convergence tolerance default of one percent and the default flowefficiency of 100 percent may be replaced in this window. The flowefficiency is a linear adjustment factor that is applied to the calculatedpressure drop to better match actual conditions.

The Moody friction factor for the pressure drop calculations may besupplied directly in this window, if desired. If no value is entered, the


Moody friction factor is calculated using the modified Colebrook-White equations.

The check box may be used toincludeor excludethe pressure dropcontribution from acceleration. Under certain high velocity or highpressure drop conditions, this term becomes unrealistically high for theBeggs-Brill-Moody equation. Therefore, under these conditions,dropping this term results in a more reasonable answer.

Note: The Beggs-Brill-Moody equation does not cover critical flow.

Line/Fitting DataLine and fitting data are supplied in thePipe Line/Fitting Datawindowwhich is reached by clicking theLine/Fitting Data icon on thePipemain data entry window. For fixed line diameter calculations, radiobuttons on this window are used to select the input mode for the pipediameter. When theInside Diameterradio button is selected, the pipeinside diameter is supplied directly. When theNominal Pipe Sizeradiobutton is selected, a drop-down list box is used to select the desiredpipe nominal diameter from a table of common pipe sizes. For thisoption, the pipe schedule may also be chosen with a drop-down listbox. When no schedule is chosen, schedule 40 pipe is assumed in mostcases.

The line length is supplied directly in this window. The maximumallowable line length is 900,000 feet (274,000 meters).

An elevation change over the line length may be entered in thePipeLine/Fitting Datawindow. A plus value indicates an increase inelevation; a minus sign indicates a decrease in elevation. The absolutevalue of the elevation change must not exceed the line length.

One fitting K-factor may be attached to a pipe unit and supplied in thiswindow. The K-factor is defined as the total resistance coefficient, andis limited to a maximum value of 100.0. Note that the suppliedK-factor may be used to represent multiple fittings, valves, and exitlosses. When a pipe unit is being used to represent a fitting or fittingsonly, a negligible line length should be provided.

Radio buttons are used to select the pipe roughness in this window. TheAbsoluteroughness may be entered in length units or theRelativeroughness may be supplied. The roughness applies to both the line and thefitting. A default absolute roughness of 0.0018 inches or equivalent (newsteel pipe) is used when no roughness is supplied.


The number of calculation segments is selected by clicking the textstring at the bottom of this window. A maximum of 50 segments maybe used. The pressure drop calculations are based on theaveragefluidproperties in a segment; therefore, it is important to use multiplesegments for systems in which the fluid properties vary significantlyover the line length (such as multiphase systems). The number ofcalculation segments has a significant effect on the calculated pressuredrop for such systems. It is also recommended that long lines bedivided into segments of 10,000 feet (3040 meters) or less. Note that adefault of one segment is used for a pipe unit unless otherwisespecified.

Note: When line sizing calculations are performed the line/fitting di-ameter and fitting K-factor cannot be supplied, and these data entryfields are not available.

Line Sizing DataLine sizing data are supplied in thePipe Line Sizingwindow which isaccessed by clicking theLine Sizing Data icon on thePipemain dataentry window. Primary sizing criterion options are:

● Maximum Pressure Drop

● Minimum Outlet Pressure

Values for the maximum pressure dropor the minimum outlet pressureare supplied directly in the data entry fields provided.

A Maximum Average Fluid Velocityconstraint may also be defined.This constraint can not be violated, and the primary sizing criterion willbe relaxed as needed to not exceed the supplied maximum velocity.

TheLine Inside Diameter Selection Methodis chosen with radiobuttons as follows:

● Use Explicitly Defined Inside Diameters

● Use Nominal Pipe Sizes

A default inside pipe diameter table with ten diameters is provided.The default values may be replaced as desired. Use theClear Allbutton to clear the pipe diameter table. TheRestore Defaults buttonrestores the ten default diameters.

A table of nominal pipe sizes and corresponding schedule numbers may besupplied in theNominal Pipe Sizeswindow which is reached by clickingthe Enter Data… button on thePipe Line Sizingwindow. Up to tenpairs of data may be provided. Nominal pipe sizes are selected from a


table of supplied values via drop-down list boxes. The correspondingschedule numbers are also selected via drop-down list boxes. Pipeschedule numbers default to schedule 40 in most cases. The Clear Allbutton may be used to clear all selected nominal pipe sizes and corre-sponding schedules.

Heat Transfer DataHeat transfer data are supplied on thePipe Heat Transferwindowaccessible via theHeat Transfer icon on thePipemain data entrywindow. The duty calculation option is selected via radio buttons:

● Fixed Duty

● Ambient Heat Transfer

● Isothermal Operation

For Fixed Dutycalculations, the supplied duty is applied evenly overthe entire length of the line. A positive value is used for heating and anegative value signifies cooling. This option with a duty of zero is usedas the heat transfer default option. This option may be used for bothforward and backward calculations.

An overall U factorandambient temperature must be provided for theAmbient Heat Transferoption. The U factor has units of energy/(area)(time)(degree). A default value of 60°F is used for the ambienttemperature. The heat transfer is computed from the pipe segment inletand outlet temperatures, U factor, pipe inside area, and the ambienttemperature. This option maynot be used with backward calculations.

The Isothermal Operationoption performs all pressure drop calcula-tions at the inlet temperature to the pipe unit. This option isnotallowed for backward calculations.

Thermodynamic SystemThe thermodynamic system for the pipe calculations may be selectedwith the drop-down list box on thePipemain data entry window. TheproblemDefaultsystem is used when no other thermodynamic systemis selected.


POLYMER REACTORGeneral InformationThePolymer Reactormodel simulates either a free radical or stepwisepolymerization process in an ideal Continuous Stirred Tank Reactor(CSTR) or Plug Flow Reactor (PFR). The polymerization reactions areassumed to take place in the liquid phase and the system is assumed tobe homogeneous. The reactors may be run in the isothermal or non-isothermal modes and the operating pressure may be set.

ThePolymer Reactorcalculation model allows for up to 79 differentreaction mechanisms to be used in copolymer free radical kinetics. Notall are intended to be used simultaneously, in fact, the fewer mecha-nisms specified for the polymer system, the more realistic and reliablethe model.

It is assumed that the polymerization reactions occur in the liquidphase. If the reaction leads to a two phase situation, a warning messageis given and the user must then specify new operating conditions tokeep the system in the one phase region.

The CSTR mass and energy balances are solved to identify a singlestable operating point. The polymer which exists at this operatingcondition is then characterized in terms of the method of moments toprovide number and weight average molecular weights.

The PFR mass and energy balances are solved to identify a sequence ofstable operating points along the axial dimension. The polymer whichexists at each point along the axial profile is then characterized in termsof the method of moments to provide number and weight averagemolecular weights.

The user must supply the feed component temperature, pressure, andcomposition along with an estimate of the temperature of theisothermal reactor or a temperature estimate for the non-isothermalreactor. Kinetic and thermodynamic data for the reaction betweenchemical species must also be provided.

Detailed InformationFor detailed information regarding operating modes, data requirements,and range of applicability of thePolymer Reactormodel, consult thePRO/II Add-On Modules User’s Guide.


PROCEDURE DATAGeneral InformationProceduresprovide a way to calculate the reaction rate based on auser’s own calculation method. The reaction rate calculation isrequired by the plug, CSTR, reactive distillation and batch reactorunits. PRO/II’s default method for reaction rate calculation is based onpower law rate expressions. For any other rate expression type (such asLangmuir-Hishelwood) or any reaction rate which deviates from thebase rate (such as a reaction with a mass transfer limitation),Proce-duresand the alternativeUser-Added Kinetic Subroutines(seePRO/IIUser-Added Subroutines User’s Guide) can be used to calculate theproper rate for reactor simulations.

Proceduresare essentially in-line routines written in a language basedon FORTRAN 77. There are two sections to aProcedure: SetupandCode. The setup section allows for the definition of eachProcedure’sname, description, variables and parameters. The code section is whereall calculations are performed. This section resembles a subroutinewritten in aFORTRAN-likelanguage.

Procedure SetupProcedures are entered in theProcedure Datadata entry window, whichis accessed thru theInput/Procedure Data…menu option or by clickingon theProcedure Datatoolbar button. EachProcedurein this windowhas a mandatory name and an optional description. As soon as the namefor a Procedurehas been entered, itsEnter Data… button becomesavailable. The button opens theKinetic Procedure Definitionwindowwhere you may click Edit/View Declaration to access theDeclarationsof variables and parameters.

➤ Any variable names entered inDefined Procedure Variableswillbe available to transfer information from the reactor unit to thePro-ceduresit calls. They can beDEFINEd in the reactor unit, and ac-cessed in the same manner as any other variable in theProcedurecode.

➤ There is only oneParameteravailable to be specified, which is themaximum number of reactions allowed. This only need be changedif the Proceduremust handle more than the default of 15 reactions.

Once setup is complete, click theHide Declaration button to close theDeclarations.


Procedure Code

Note: The Procedure Code section is required and must terminate witha RETURN statement.

The actualFORTRANprocedure is entered directly in theCodefield ontheKinetic Procedure Definitiondata entry window. You may checkthe procedure as you compose it by clicking theCheck Code button.The following predefined varibles are provided from the calling reactorunit:

➤ Kinetic data: These are the kinetic parameters are provided via theK… button of theReaction Datasection, and/or theUnit Reaction Definitions… button of theReactorunit.

➤ Reactor data: These data include the reactor sizing parameters andoperating conditions.

➤ Property data: These data include the thermophysical property dataof the pure components (e.g., molecular weight or critical pressure),and the property data of the individual components and mixture atthe reaction conditions.

➤ User data: These are the integer, real, and supplemental data pro-vided by the user via theEnter Data… button when the procedurename is specified for rate calculations for aReactorunit.

➤ Procedure data: These are the defined procedure variables enteredduring theProceduresetup. Their values areDEFINEd in the samewindow as the User data.

The supported language features are discussed below.

Elements of the LanguageEach statement contains a maximum of 80 characters. An ampersand(&) at the end of a line indicates continuation on the following line.Note that an asterisk(*) is not valid as a continuation marker, since itsignifies multiplication.

All lines of code except the CODE statement may be preceded by aunique numeric label from 1 to 99999 (shown as “nn” in this manual).

A dollar sign (“$”) causes all following data on the line to be inter-preted as a comment rather than as code. Unlike in FORTRAN, a “C”in column 1 does not designate a comment statement.


Predefined VariablesThe following variable names are reserved. They are used to passvalues between the procedure and the unit operation that uses theprocedure.

The first tables list variables thst provide input values to the procedure.They may not appear on the left side of an assignment statement.

Procedure Data Predefined REAL Scalar Variables

Variable Name PFR CSTR Batch RxDist

REAL Scalar Variables - Supplied in standard problem dimensional units

Temperature RTEMP X X X X

Pressure RPRES X X X X

Total Molecular weight RMW X X X X

Vapor Phase RVMW X

Liquid Phase RLMW X

L1 Phase RL1MW X

L2 Phase RL2MW X

Specific gravity (60/60) RSPGR X X X X

Total Molar Rate RMRATE X X X X

Vapor Phase RVMRAT X

Liquid Phase RLMRAT X

L1 Phase RL1MRA X

L2 Phase RL2MRA X

Weight Rate RWRATE X X X X

Standard Volumetric Rate RSVRAT1 X X X

Actual Volumetric Rate RAVRAT1 X X X

Vapor Phase RVVRAT X

Liquid Phase RLVRAT X

L1 Phase RL1VRA X

L2 Phase RL2VRA X

Liquid Fraction RLFRAC X X X X

L1 Phase RL1FRA X

L2 Phase RL2FRA X

Vapor PhaseViscosity RVVISC X X X X

Liquid Phase Viscosity RLVISC X X X X


Procedure Data Predefined REAL Scalar Variables


REAL Scalar Variables - Supplied in standard problem dimensional units

Vapor Phase Conductivity RVCOND X X X X

Liquid Phase Conductivity RLCOND X X X X

Vapor Phase Sp. heat RVCP X X X X

Liquid Phase Sp. heat RLCP X X X X

Surface tension RSURF X X X X

Absolute Temperature RTABS X X X X

Tube Diameter (fine length) TDIAM X

Tube Length TLEN X

Cumulative Length CUMLEN X

Plug Flow Step Size (finelength)

DELX X

Total reactor volume (CSTR& BATCH) or volume step-size of PLUGFLOW reactor

VOLUME X X X

Vapor Phase Volume RVVOLU X

Liquid Phase Volume RLVOLU X

L1 Phase Volume RL1VOL X

L2 Phase Volume RL2VOL X

Gas Constant RGAS X X X X

1 Volumetric flowrates for CSTR and PLUGFLOW are calculated using bulk compositionsassuming the specified reactor phase, even if the phase is actually mixed. A warning isprinted if the actual phase is mixed.


Procedure Data Predefined INTEGER Scalar Variables


Total # of components NOC X X X X

Total # of reactions NOR X X X X

Reaction phase IRPHAS X X X

Basis for Rate Calculation0 = molar1 = partial pressure2 = fugacity3 = mole-gamma

ICPFA X X X

Step # ISTEP X

Unit # for output file IOUT X X X X

Unit # for index file INDX X X X X

Maximum # of reactions MAXNOR X X X X

Procedure Data Predefined REAL Variable Arrays


Dimension : NOC

Total Molar Composition XTOTAL X X X X

Total Molar Concentration XCONC X X X

Vapor Phase XVCONC X

Liquid Phase XLCONC X

L1 Phase XL1CON X

L2 Phase XL2CON X

Vapor Phase Fugacity XVFUG X X X X

Liquid Phase Fugacity XLFUG X

L1 Phase XL1FUG X

L2 Phase XL2FUG X

Liquid Phase Activity XLACT X X X X

L1 Phase XL1ACT X

L2 Phase XL2ACT X

Vapor phase Mole Fractions XVAP X X X X

Liquid phase Mole Fractions XLIQ X X X X

L1 Phase XLIQ1 X


Procedure Data Predefined REAL Variable Arrays


L2 Phase XLIQ2 X

Vapor phase Mass Fractions XVMFRA X

Liquid phase Mass Fractions XLMFRA X

L1 Phase XL1MFR X

L2 Phase XL2MFR X

Dimension: 70Real numbers supplied onRDATA statement

RDATA X X X X

Dimension: 200Real numbers supplied onSUPPLE statement

SUPPLE X X X X

Dimension: NORActivation Energy*Pre-exponential factorTemperature Exponent

ACTIVEPREEXPTEXPON

XXX

XXX

XXX

XXX

Dimension: (NOC,NOR)Stoichiometric factorReaction order

STOICHORDER

XX

XX

XX

XX

* There is an important distinction between the values of activation energy for in-line proce-dures and calculations involving local reaction sets in distillation columns or reactors. Thevalues of activation energy supplied the reference reaction set (in RXDATA) or in the localreaction sets are assumed to be in thousands of energy units per mole units, whereas, in the caseof procedures, the user-supplied value is used without the above assumption. E.g., for the SIsystem, a value ofACTIV=123 kJ/kmol in the RXDATA or local rxnset is used as 123,000 kJ/kmol in calculations.A procedure using the same variable, say ACTIV(1), would calculate based on a value of 123kJ/kmol.


Procedure Data Predefined INTEGER Variable Arrays


Dimension: 10Integer supplied onIDATA statement

IDATA X X X X

Dimension: NORBase Component IDBASE X X X X

Basis for Rate Calculation foreach reaction (liquid phase)

0 = molar1 = partial pressure2 = fugacity3 = mole-gamma4 = mole fraction5 = mass fraction

ILBASI X1 X

Basis for Rate Calculation foreach reaction (vapor phase)

0 = molar1 = partial pressure2 = fugacity3= mole-gamma4 = mole fraction5 = mass fraction

IVBASI X1 X

Dimension: (NOC,NOR)Phase of components in rxn

1 = Vapor2 = Liquid

IPHASE X

1 Available only for Boiling Pot CSTR


The following variables are the PROCEDURE block results available toPRO/II after control is returned to the PLUGFLOW, CSTR or ReactiveDistillation unit operation. RRATES must be defined for all reactions.

PROCEDURE Results

VariableName

PFR CSTR Batch RxDist

Values of solution flag:0 Default value. PRO/II assumes

the PROCEDURE step hassolved.

1 PROCEDURE solved.2 PROCEDURE failed, but continue

calculations if in a recycle orcontrol loop.

3 PROCEDURE failed, stop allflowsheet calculations.

ISOLVE X X X X

Reaction rates for each reactionmoles/ (liqvol*time) for

OPERATION PHASE=L1, Bmoles/(vapvol*time) for

OPERATION PHASE=V1

RRATES(NOR)

X X X X

Temperature derivatives for each reaction DRDT(NOR)2

X

Composition derivatives for each reaction DRDX(NOC, NOR)2

X

1 CSTR and PLUGFLOW should not be used when multiphase reactions are expected. Exceptfor Reactive Distillation and the CSTR boiling pot model, PRO/II assumes the phase is 100%liquid or vapor as defined on the OPERATION statement.

2 The use of this is optional.

Procedure Data Programming LanguageSee the discussion of theCalculatormodule at the beginning of thischapter for a survey of the proper use ofDeclaration Statements(9-6),Assignment Statements(9-7),Fortran Intrinsic Functions(page 9-8),PRO/II Intrinsic Functions(page 9-9),IF Statements(page 9-11),Calculation Flow Control Statements(page 9-12), andCalculationTermination Statements(page 9-14).


PUMPGeneral InformationThePumpmay be used to compute the energy required to increase thepressure of a process stream. This quantity of energy is added to thefeed enthalpy to determine the outlet temperature. Only one liquidphase is considered in the calculations.

Feeds and ProductsA pump operation may have multiple feed streams, in which case theinlet pressure is assumed to be the lowest feed stream pressure. Asingle liquid product stream is allowed from a pump.

Outlet ConditionsThe Pressure Specification for a pump is selected with the appropriateradio button on thePumpmain data entry window as:

● Outlet pressure

● Pressure rise (∆P)

● Pressure ratio based on the lowest feed stream pressure.

Pump EfficiencyA pumping efficiency in percent may be supplied in the data entry fieldprovided on thePumpmain data entry window. This value is used forthe work and outlet temperature calculations. If not supplied, a defaultvalue of 100 percent is used.

Thermodynamic SystemThe thermodynamic system of methods to be used for pump calcula-tions may be selected by choosing a method from theThermodynamicSystemdrop-down list box on thePumpmain data entry window.


REACTION DATAGeneral InformationUse theReaction Data Setsdata entry window to supply reaction stoi-chiometry, heat of reaction, kinetic and equilibrium data, and to specifythe base component for each reaction. One or more reactions may besaved as separate reaction data sets and used in all reactor types(conversion, equilibrium, Gibbs free energy minimization, plug flow,CSTR, and boiling pot reactors). Multiple unit operations can havecommon access to the same reaction data.

The PRO/II graphical user interface now supports multiple equilibriumexpressions for eachEquilibrium Reactor.

Note: You may specify the base component of the reaction and provideheat of reaction and equilibrium and kinetic data in the Reactor dataentry window. For conversion reactors, these data are considered tobe local and are entered at the unit operation level. See the Reactorsection later in this chapter.

To access theReaction Datawindow:➤ Click on theReaction Dataicon on the main toolbar.

Note: Any data entered in the Reaction Data window will be passed tothe Unit Reaction Definitions window (a subwindow of the main Reac-tor window) and used as default values.

Specifying Reaction SetsProvide a name and description for each reaction data set in the mainReaction Datawindow. The name is required, but the description isoptional.

Note: You must define the component list in the Component Selectiondata entry window before entering reaction data. This order is impor-tant because components for each reaction must be selected from a pre-viously defined component list .

To enter data for each newly defined reaction data set, or to modifythe data for imported sets:➤ Click on the Enter Data… button for that set.

This opens theReaction Definitionswindow for that set. Here you mayenter the following information for the reaction data set:


● Kinetic rate calculation method

● The name of all reactions in the set (required)

● The reaction stoichiometry (required)

● The heat of reaction and the base component (required)

● Equilibrium data (optional)

● Kinetic data (optional).

To select the kinetic rate calculation method:

The kinetic rate can be calculated from PRO/II’s reaction rate subrou-tine based on the power law rate expression, by an inline procedure orby the user’s kinetic subroutine. The inline procedure must be firstdefined in theProcedure Datasection and selected from theProcedureNamedrop down list box. When a user-added kinetic subroutine isused, it can be selected from theSubroutine Namedrop down list box.The user’s added kinetic subroutine must be named as one of the fiveUSKIN1, USKIN2, USKIN3, USKIN4 and USKIN5 routines andlinked to PRO/II as described in thePRO/II UAS/PDTS InstallationGuide.

To define the stoichiometry:

Define the reaction stoichiometry by clicking on the linked textReactants = Productsin theDefinition column to open theReactionComponentswindow. Here you may select the reactants and productsfor the reaction and supply the stoichiometric coefficient for each. Youmay define the reaction based on the chemical formula of thecomponent (library components only), or based on the name (forlibrary, non-library, or petro components).

To define the heat of reaction:

You may define the heat of reaction for any selected reaction in aspecific reaction data set in theHeat of Reaction Datawindow. Thiswindow appears when you click on theH… button beside theselected reaction on theReaction Definitionswindow. In this windowyou may choose one of two options:

Calculated from Heat of Formation: This option allows PRO/II to calculatethe heat of reaction based on the heats of formation for the reactioncomponents. This is the default.

User-specified: You supply the heat of reaction (in units of energy/weight). If you do so, you may also optionally supply the referencetemperature, component, and reference reaction phase.


Note: You must supply heat of reaction data for non-library compo-nents that do not have heat of formation data. You must also specify thebase component for the reaction.

To supply equilibrium data for a specific reaction in a reaction dataset:➤ Click on the E… button beside the selected reaction in theReac-

tion Definitionswindow. TheReaction Equilibrium Datawindowappears.

➤ Click on theDefine Equilibrium Datacheck box to enter equilib-rium data.

You may supply the following data in this window:

Equilibrium Coefficients: Up to 8 (A-H) coefficients for the equilibriumequation (at least one coefficientmustbe supplied).

Units: Temperature, weight, volume and pressure units of measure forthe equilibrium data may be supplied by clicking on the linked (under-lined) text in the units box. (If you do not change the temperature units,the global units are used by default).

Equilibrium Constant Expression: The default reaction phase, reactionactivity bases for both vapor and liquid phases, component reactionphases and exponent orders can be entered here. Click on the ActivityExponent and Activity Phase button to specify the exponent order andactivity phase for each component in the reaction. The vapor activitybasis is used for all components specified with vapor phase activityphase while the liquid activity basis is used for all componentsspecified with liquid phase activity phase.

To supply kinetic data for a specific reaction in a reaction data set:➤ Click on the K… button beside the selected reaction in theReac-

tion Definitionswindow. TheReaction Kinetic Datawindowappears.

➤ Click on theDefine Kinetic Datacheck box to enter kinetic data.

You may supply the following data in this window:

Pre-exponential Factor (A): The pre-exponential factor of the power lawkinetic rate equation for the reaction. The default is 1.0.

Activation Energy: The activation energy of the power law kinetic rateequation for the reaction in units of energy/weight. A default of zero isused if a value is not supplied.


Temperature Exponent: The temperature exponent of the power lawkinetic rate equation for the reaction. A default of zero is used if a valueis not supplied.

Reaction Order and Activity Basis: The default reaction phase, reactionactivity bases for both vapor and liquid phases, component reactionphase and kinetic orders that are used to define the kinetic rate expres-sion can be entered here. Click theReaction Order and Activity Phasebutton to specify the kinetic reaction order and activity phase for eachcomponent which appeared in the rate expression. The vapor activitybasis is used with all components specified with vapor activity phasewhile the liquid activity basis is used with all components specifiedwith liquid activity phase.


REACTORGeneral InformationTheReactorunit operation simulates the operation of many chemicalreactors including conversion reactors, equilibrium reactors, Gibbs (FreeEnergy Minimization) reactors, Plug Flow Reactors (PFRs), ContinuousStirred Tank Reactors (CSTRs), and Boiling Pot Reactors.

In addition to the above reactor types, PRO/II contains built-in Shift andMethanation reaction data sets for either conversion or equilibriumreactors.

Feeds and ProductsEach reactor may have one or more feed streams. A multiphase productfrom the reactor may be separated into streams containing one or morephase. The allowable product stream phases arevapor, liquid, decantedwaterandmixed(vapor+liquid). A mixed phase product is not allowedwith a vapor or a liquid product. The decanted water product is also usedas the second liquid product phase with rigorous VLLE calculations.

If this is more than one product stream, the phases must be allocated tothe streams in theProduct Phases window. Access this window byclicking the Product Phases… button on the mainReactordata entrywindow for the particular reactor type.

Reactor TypeFor conversion, equilibrium, Gibbs, or plug flow reactors, select thereactor type by choosing the appropriate reactor icon from the PFDpalette. CSTR and boiling pot reactors share the CST/Boiling PotReactors icon. Select the desired reactor type from a drop-down list boxon the mainReactordata entry window.

Reaction SetFor all reactor types other than the Gibbs reactor, you must select areaction data set from theReaction Set Namedrop-down list box(options include a built-in reaction set, e.g., Shift reaction, or a user-defined set) on theReactormain data entry window. For the Gibbsreactor type, either no reaction data set may be selected (option None),or a user-defined set may be specified. See theReaction Datasectionearlier in this chapter for more information on specifying reaction datasets.


Thermal SpecificationsFor most reactor types, the fixed operating temperature, the temperaturerise across the reactor, or the fixed reactor duty may be specified byusing radio buttons and entering values in the appropriate data fields.The available options are:

Temperature Rise: This is the temperature increase across the reactor. Thisoption is available for conversion and equilibrium reactors only where it isthe default.

Combined Feed Temperature: The average temperature for all feedstreams to the reactor. This is available for plug flow and Gibbsreactors, and CSTRs only where it is the default.

Fixed Temperature: You may specify the final reactor temperature for allreactor types.

Fixed Duty: You may specify the reactor duty for all reactor types. Adefault value of 0 will be used if a value is not specified. The followingadditional reactor information may also be given via the main Reactorwindow:

External Heat: For plug flow reactors only, you may specify informa-tion on the external heating or cooling source by selecting this option,clicking on the Enter Data… button, and entering data in theExternalHeating/Coolingwindow.

Temperature Profile: For plug flow reactors only, you may enter the reactortemperature profile in tabular form as a function of the actual reactor length,or as a function of percent or fractional distance along the reactor.

Reactor DataClick on the Reactor Data… icon on the mainReactordata entrywindow to open theReactor Datawindow where you can supplyreactor configuration information.

Conversion and Equilibrium ReactorsFor these reactor types, you may chose an error handling option byclicking on the Stop calculationshypertext. The options are:

Stop Calculations: This stops calculations if an error occurs (e.g., fornegative component flows). This is the default.

Continue Calculations with no Reaction: Continue calculations with noreaction if an error occurs.

Add Makeup of Limiting Reactant: Reduce conversion by adding a make-upof the limiting reactant if an error occurs.

Reduce Conversion: Reduce conversion if an error occurs.


Continuous Stirred Tank ReactorYou must provide the reactor volume for CSTRs in theReactor Datawindow. Optionally, you may also provide estimates of the productflowrate.

Plug Flow ReactorEnter the following data for PFRs in theReactor Datawindow:

Reactor Length: The total length of the reactor. This is required.

Tube Inside Diameter: The inside diameter of the PFR tubes. This isrequired.

Number of Tubes: The total number of tubes in the PFR. Default is 1.

Number of Points for Profile: The number of equidistant locations alongthe reactor length for the temperature profile. Default is 10.

Integration Options: You may select one of four integration options:

● Fixed step size Runge-Kutta method. The Runge-Kutta methodwith 20 steps is the default.

● Runge-Kutta method with user-specified step size.

● Gear integration method with user-specified gear tolerance(default tolerance = 0.1%).

● LSODA (Livermore Solver of Ordinary Differential Algebraicequations) method with user-specified tolerance (defaulttolerance = 0.1%).

Boiling Pot ReactorYou may supply the following reactor calculation options for theboiling pot reactor in theReactor Datawindow:

Tolerances: The absolute temperature and relative mole fraction andenthalpy tolerances for the reactor may be changed from their defaultvalues of 0.1º, 10-5, and 10-4 respectively.

Note: If the Fixed Duty option is specified on the main Reactor data en-try window, anestimate of the reactor temperature may optionally be pro-vided in the Reactor Data window. The minimum and maximumtemperature defaults of - 457.87 F and 4940.33 F may also be overridden.

Maximum Liquid Volume: If a fixed volume is not supplied on the mainReactorwindow, you may supply a maximum liquid reactor volume inthis window. A default of 3531.5 ft3 will be used if a value is notprovided.


Initial Volume Estimate: An initial volume estimate may optionally besupplied in this window.

Component product rate estimates may also be supplied by clicking onthe Product Estimates… button on theReactor Datawindow.

The number of Broyden trials before the Jacobian matrix is updatedmay be specified along with the derivative step size multiplier byclicking on the appropriate underlined linked text. The defaults are 3trials and a step size multiplier of 0.01.

Gibbs ReactorFor the Gibbs reactor, the user may provide a number of optional calcu-lation options in theReactor Datawindow:

Maximum Iterations: The maximum number of iterations allowed. Thedefault is 50.

Convergence Tolerance: The relative convergence tolerance. The defaultis 10-4 for isothermal conditions and 10-6 for adiabatic conditions.

Fibonacci Tolerance: The convergence tolerance for the Fibonacci searchcalculations. The default is 0.01.

In addition, you may specify the physical property evaluation methodby clicking on the underlined hypertext. The options are:

Evaluated at each step: The physical property values are reevaluated ateach step of the search. This is the default.

Used from previous iteration: The physical property values from theprevious iteration are used.

You may select the product rate estimate optionby clicking on theunderlined linked text. The available options are:

PRO/II default: The default generates an initial estimate of the productrates using the PRO/II method.

Average of all feeds: This uses the average of all feed rates to generate aninitial product rate estimate.

Supplied reacting component rates: This option uses the values given forthe reacting component estimated rates.

Supply reacting components and estimated rates in theReactingComponentswindow which is reached by clicking the ReactingComponents and Estimates button on theReactor Datawindow.

The options to specify the parameters for the free energy minimizationphase calculations are found in thePhase Split Parameterswindow


which is opened through the Phase Split Parameters button on theReactor Datawindow.

Note: ThePhase Split Parameterswindow is available only if theRe-actor Operation Phaseis specified asCalculatedon theUnit ReactionDefinitionswindow. See below forUnit Reaction Definitions.

The options available on thePhase Split Parameterswindow are:

Initial Phase Estimate: This entry is the phase used for the initial reactorcalculations. The user may select thevapor, liquid, vapor-liquid,liquid-liquid, or vapor-liquid-liquidphase. The default isvapor-liquid.

First Phase Evaluation at Iteration: Specify the first iteration where thephase will be reevaluated. The phase should not be evaluated too earlybecause the reaction results may still be far from the final solution. Thedefault is 6.

Phase Evaluation Frequency: Specify the number of iterations betweenphase evaluations. The default is 4.

Minimum Phase Tolerance: When the molar ratio of a phase to the totalquantity of material is less than this value, the phase is considered as non-existent. The default is 10-6.

Atomic groups can be provided in theAtomic Groupswindow. Thiswindow can be reached by clicking theUser-specified Atomic Groupsbutton on theReactor Datawindow.

Unit Reaction DefinitionsThe reaction phase, heat of reaction, equilibrium data, and kinetic datafor the reactor may be entered in theUnit Reaction Definitions window.Bring up this window by clicking on theUnit Reaction Definitions…button on the mainReactorwindow.

Note: Any data previously entered in the Reaction Data Category win-dow will be transferred to the Unit Reaction Definitions window andused as default values. You can overwrite the data for a particular re-actor in the Unit Reactions Definitions window for that reactor.

Equilibrium ReactorYou may supply the operation phase of the reactor in theUnit ReactionDefinitionswindow. By clicking on the Equilibrium Data… button inthis window, you gain access to the fields where you may supply thefollowing:


Equilibrium Coefficients: Eight coefficients (A-H) of the equilibriumequation.

Units: The temperature, weight, volume and pressure units of measurefor the equilibrium equation can be changed by clicking on the under-lined linked text. Options are restricted to ºR or K for the temperatureunits.

Conversion ReactorYou may overwrite the stoichiometric coefficients for the first reactionin the selected reaction set by clicking theDefine the Stoichiometry forthe First Reactioncheck box. The values of stoichiometric coefficientsare to be determined from the calculation results of the selected calcu-lator unit. Frequently, this feature is applied as a way to use a singlereaction to represent the overall reaction behavior in the reactor and,therefore, there is only a single reaction defined in the entire reactionset. The stoichiometric data displayed in the grid box are merely usedto echo the reaction equation previously defined in theReaction Datasection.

Continuously Stirred Tank Reactor and Boiling Pot ReactorYou may supply the reactor operation phase, reaction activity basis andkinetic rate calculation method in theCSTR UnitReaction Definitionswindow.

Reactor Operation Phase: The options arevaporor liquid phase for theCSTR, but restricted to liquid phase for the BPR.

Reaction Activity Basis: For vaporphase, the options areMolar Concen-tration, Partial Pressureor Fugacity. For liquid phase, the options areMolar Concentration, Fugacityor Activity. Currently, only homoge-neous reaction rate expressions based on either vapor or liquid phasereactions are allowed for the CSTR. For BPRs, heterogeneous reactionrate expressions are allowed.

Kinetic Rate Calculation Method: The options arePower Law, User AddedSubroutineor Kinetic Procedure. If the default is used, the reation ratesare computed by power law kinetics in the form of the generalArrhenius equation. For any of these methods, kinetic data can beentered through theKinetic Data… button.

Power Law: The default method.

User Added Kinetic Subroutine: This option directs the CSTR mod-ule to use a User-added Subroutine (UAS) written in FORTRAN toperform reaction rate calculations. Specify a Subroutine Name intheUnit Kinetic Datawindow. The identifiying arguments for thesubroutine name “U1”, “U2” … “U5” correspond to user-added


subroutines “USKIN1” … “USKIN5”, respectively. After selectingthe user added kinetic subroutine, you can enter local values (i.e.,specific just to this reactor) for variables to be used for the rate cal-culation. Use the upper left table to supply local values for an arrayof real variables, the lower left table for any array of integer vari-ables and the upper right for an additional (Supplemental) array ofreal variables. These local data, kinetic reaction data specified inthe selected reaction set, and thermophysical property data of thereaction mixture will be provided to the selected kinetic subroutinefor reaction rate calculations. Refer to thePRO/II User-added Sub-routine User’s Manualfor instructions on creating and installingUASs.

Kinetic Procedure: This option directs the CSTR module to use auser-supplied in-line kinetic Procedure to perform reaction rate cal-culations. After selecting the name of the Procedure (which must befirst defined in the Procedure Data section), you can enter valuesfor local variables in a way similar to that for theUser Added Ki-netic Subroutinementioned above. Additionally, you may providethe values for those procedure variables (PDATA) used by the se-lected Procedure.

Plug Flow ReactorData that may be specified for the Plug Flow Reactor are the same asthose described above for the CSTR.

Pre-exponential Factor: The pre-exponential factor for the kinetic powerlaw rate equation. The default is 1.

Activation Energy: The activation energy for the kinetic power law rateequation. The default is 0.

Temperature Exponent: The temperature exponent for the kinetic powerlaw rate equation. The default is 0.

Base Component: A base component must be supplied for the kineticreaction rate report.

Reaction Order and Activity Basis: As is done in the Reaction Datasection on a global basis, the default reaction phase, reaction activitybases for both vapor and liquid phases, component reaction phase andkinetic orders that are used to define the kinetic rate expression can beentered here as local data for this reactor. Click on theReaction Orderand Activity Phasebutton to specify the kinetic reaction order andactivity phase for each component which appears in the rate expression.The vapor activity basis is used for all components specified with vapor


activity phase while the liquid activity basis is used for all componentsspecified with liquid activity phase.

Gibbs ReactorYou may specify the phase of the reactor operation in theUnit ReactionDefinitionswindow. The reaction phase options areCalculated(default),Vapor, Liquid, Vapor-Liquid, Liquid-Liquidor Vapor-Liquid-Liquid. If Calculatedis selected, PRO/II will determine the phase aspart of the free energy minimization calculation. If a phase is selected,the calculations wil be based on the selected phase.

Extent of ReactionTo specify the extent of the reaction for a conversion, equilibrium andGibbs reactors only. Click on theExtent of Reaction… button on themainReactordata entry window to open theExtent of Reactionwindow.

Conversion ReactorYou may select the base component from which the conversion datawere determined. If the base component is not selected (select “none”),the stoichiometric coefficients of the reaction will be taken as theabsolute moles reacted. You may supply constants for the second ordertemperature-dependent fractional conversion equation in this window.Default values for the constants are given in the table. Click on theunderlined linked text to change the temperature units of measure forthe conversion reaction. If the temperature units of measure are notspecified locally, the problem temperature units are used.

Equilibrium ReactorThe base component for user-supplied reactions must be specified inthis windowExtent of Reactionwindow. You may access this windowvia theReaction Setwindow which contains a list of the reactions thathave earlier been defined for the flowsheet. Upon choosing the desiredequation, theExtent of Reactionwindow appears. (The base compo-nents of built-in reactions such asShiftandMethanationare predeter-mined and need not be supplied by the user.)

You may specify the approach to conversion either as a temperature ora fractional approach. As was the case with theConversionreactor, youmay supply constants for the second order temperature-dependent frac-tional conversion equation in this window. Default values for theconstants are given in the table. Click on the underlined linked text tochange the temperature units of measure for the conversion reaction. Ifthe temperature units of measure are not specified locally, the problemtemperature units are used.


Gibbs ReactorThe extent of reaction can be provided on a global basis in theExtent ofReactionwindow (as a component percent converted, or as acomponent product rate). The extent of reaction can also be specifiedfor each individual reaction as a temperature approach or a basecomponent product rate.

Amount of CatalystFor boiling pot reactors only, you can specify the amount of a nonvola-tile catalyst componenton a weight or molar fraction, or total weight ormole basis in theCatalytic Componentswindow (which may bereached by clicking on the Catalysts button on the Reactor Datawindow). Before the button becomes active, the following conditionsmust be met:

● You must specify the catalytic component with a reactionstoichiometry of ‘0.’ (Input/Reaction Data(Enter Data…)/Reaction Definitions(Definition)/ Reaction Components). Seethe previous section on Reaction Data for more information ondefining reaction data sets.

You must specify the reaction order for the catalytic component as anynumber other than ‘0’ in the Reaction Order & Activity Phasewindow.This window may be accessed by clicking on the like-named button locatedon theUnit Reaction Definitions/Unit Kinetic Datawindow for the boilingpot reactor, or by the following path:Input/Reaction Data(EnterData…)/Reaction Definitions/(K…)/Kinetic Reaction Data(ReactionOrder & Activity Phase).

PressureFor conversion, equilibrium, Gibbs reactors and CSTRs, clicking the

Pressure button on the mainReactorwindow allows you to enter thefollowing reactor pressure options in thePressuredata entry window:

Pressure Drop: The pressure drop across the reactor. This defaults to 0 ifnot supplied.

Outlet Pressure: The pressure at the reactor outlet.

For the plug flow reactor, either the inlet and outlet pressure or apressure profile along the reactor length (actual length, or percent orfraction of tube length) may be entered on thePressurewindow:

Inlet: Either the pressure drop below feed (the default is 0 psi), or theinlet pressure may be supplied.

Outlet: Either the pressure drop below inlet (the default is 0 psi), or theoutlet pressure may be supplied.


Print OptionsFor all reactor types except the Gibbs reactor, the following print optionis available through the Print Options window:

Print Calculation Path for Enthalpy Balance: This option prints the calcula-tion path for the heat of reaction calculation.

Thermodynamic SystemThe thermodynamic system of methods for the reactor calculations maybe selected by choosing a method from theThermodynamic Systemdrop-down list box on the mainReactorwindow.


REACTOR, BATCHGeneral InformationTheBatch Reactorunit operation models material production as aresult of simultaneous and/or sequential reactions in the liquid contentsof a reactor vessel. Phase equilibrium analysis during the reactionallows for the tracking or removal of vapor phase products. TheBatchReactormay be run in a true batch simulation mode, with the reactantscharged to the reactor vessel prior to the onset of reactions, and producttaken from the vessel at the end of reaction process, or in a semi-batchmode where reactants may be introduced throughout the reactionprocess. Batch reactor calculations may also be integrated into asteady-state process simulation. The unit configuration automaticallyconsiders the presence of holding tanks for steady flow streams toprovide the time-variant reactants to the batch unit. Implicit holdingtanks are also considered for the product streams to provide a couplingof the time-variant process to the continuous process simulation envi-ronment. A representation of the product steady flow stream comesfrom an overall process time average of the quantity accumulated into agiven product.

Currently, theBatch Reactorsupports only liquid-phase reactions. Areaction may produce one or more vapor constituents. Whether thevapor constituent(s) will return to the liquid phase and again beavailable for reaction(s) will be determined by equilibrium analysisdone at the end of each time step.

Thermodynamic SystemThe thermodynamic system for the unit is selected by using theTher-modynamic Systemdrop-down list box in theBatch Reactordialog box.Batch Reactoralso allows the use of electrolyte thermodynamicmethods.

Detailed InformationFor detailed information about the use of theBatch Reactorunitoperation, consult thePRO/II Add-On Modules User’s Guide.


SOLID SEPARATORGeneral InformationTheSolid Separatorunit models the separation of solid phase materialfrom a mixture of feed streams. The unit operates adiabatically at thelowest of the individual feed stream pressures.

Feed and Product StreamsThe solid separator unit can have up to ten (10) feed streams. The inletthermal condition is determined by an adiabatic flash calculation at thelowest feed stream pressure.

The solid separator requires both overhead and bottoms productstreams.

Calculation MethodThe solid separator provides the option of specifying the fraction of thesolid components in the total feed that is removed in the bottomsstream. The default fraction of the solid components removed in thebottoms stream is 1.00. An adiabatic flash calculation is used todetermine the product phases and the outlet temperature based upon thethermal condition of the combined feed.

The solid separator unit supports bothVLE (two phase) andVLLE(three phase) calculations to determine the individual phase composi-tions. See the onlineTechnical Informationdiscussion entitledVLEModelandVLLE Modelfor more details. To access the main data entrywindow for VLE andVLLE calculations, selectTools/Binary VLEfromthe menu bar.


SPLITTERGeneral InformationThis unit may be used to split a single feed or mixture of feeds into twoor more products ofidenticalcomposition and phase condition. Theoutlet stream pressure may be specified, if desired, and an adiabaticflash used to determine the outlet temperature and phase. A choice ofoptions is provided for splits in which insufficient feed is available tomeet the specified product rates.

Feeds and ProductsA splitter may have multiple feed streams. The lowest feed pressure isused for the pressure of the combined feed.

A splitter must have two or more product streams. All product streamshaveidenticalcompositions and phase conditions. Phase separation ofproduct streams is not available in this unit, and, if desired, aFlashunitoperation must be used for this purpose.

Product Rate SpecificationsFor a splitter with N product streams, N-1 product stream ratesmustbespecified. Product rate specifications are supplied by clicking on theunderlined hypertext strings in theProduct Rate Specificationssection oftheSplittermain data entry window. All of the splitter product streams arelisted and any one may be used for the unspecified rate.

Specifications use the general specification format and are furtherdescribed in theSPEC/VARY/DEFINEsection of this chapter. Onlyspecifications that arerate dependentare allowed, e.g., stream orcomponent(s) rate total, stream or component(s) recovery, streamenthalpy, etc.

Outlet Pressure SpecificationThe outlet pressure for the splitter products may be changed byapplying a pressure drop to the lowest feed pressure. This value issupplied in thePressure Specificationwindow which is accessed byclicking the Pressure Specification… button on theSplittermain dataentry window.

When a pressure drop is supplied, the resulting outlet temperature andphase condition are determined by an adiabatic flash calculation fromthe composite feed inlet conditions.


Inadequate Feed Rate OptionsThere are two options for situations in which insufficient feed isavailable to satisfy all product stream rate specifications. They may beselected by radio buttons on theSplittermain data entry window:

Satisfy Each Specification in Order Until Feed is Exhausted: Each specificationis satisfied in the order of the products until the feed is exhausted. Theproduct stream that encounters insufficient feed is limited to the feedavailable and the remaining products are assigned zero rates. (This isthe default option.)

Satisfy Each Specification and Normalize Flowrates if Needed: All specifiedproduct rate specifications are satisfied and the resultant rates arenormalizedto the total feed rate. The product with the unspecified rateis assigned a zero flow.

The order of the product streams in the list box may be changed, ifdesired, by clicking theChange Stream Specification Order… buttonon theSplittermain data entry window. You can reset a stream specifi-cation by clicking the Reset Stream Specification button on theSplittermain data entry window.

Thermodynamic SystemThe thermodynamic system of methods to be used for splitter calcula-tions may be selected by choosing a method from theThermodynamicSystemdrop-down list box on theSplittermain data entry window.


STREAM CALCULATORGeneral InformationTheStream Calculatorunit blends any number of feed streams andsplits them into two product streams with defined compositions andthermal condition. It may also be used to create a pseudoproductstream based on the blended feeds or by defining the amount of eachcomponent in the stream.

Feeds and ProductsThe stream calculator may have any number of feed streams. Scalefactors (positive or negative) may be applied to all feeds in theFeedScalingwindow in order to create a mixed feed with the desiredcomposition. If scale factors other than 1.0 are used, the unit will notmaterial balance. Multiple feed streams are flashed at the lowest feedstream pressure.

For stream splitting, both the overhead and bottoms product arerequired. In order to create a stream, a pseudoproduct must be defined.The feeds may be split and a pseudoproduct created in the same streamcalculator unit. If there is no feed to the unit, only a pseudoproductmay be specified.

A multiphase product from the stream calculator may be separated intostreams containing one or more phase. The allowable product streamphases are vapor, liquid, decanted water and mixed (vapor+liquid). Amixed phase product is not allowed with a vapor or a liquid product.The decanted water product is also used as the second liquid productphase with rigorous VLLE calculations.

If any product, overheads or bottoms, has more than one streamattached, the phases must be allocated to the streams in theProductPhaseswindow which is accessed by clicking theProduct Phasesbutton in the overhead or bottoms product windows.

Mode of OperationThe mode of operation is specified by the number of feeds and productsattached to the unit so it is important to connect the streams correctlybefore entering the unit data.

Stream SplittingIn order to define the component splits, specifications must be enteredin theProduct Specificationswindow to define how much of eachcomponent goes into either the overhead or the bottoms product.Specifications may be on single components or on ranges of contiguous


components. Several specifications may be required and some mayspecify the amount of components in the overhead and others theamount in the bottoms product. Each component must appear in one,and only one, specification. The component rates, recovery or compo-sition in a product may be specified.

The thermal condition of the products may optionally be defined in theOverhead Product Conditionswindow and theBottoms Product Condi-tionswindow. Pressure defaults to the lowest feed pressure. If notemperature specification is supplied for either product, the producttemperatures are set equal at a value calculated from the enthalpybalance, using the duty entered on theStream Calculatorwindow. Ifone temperature is supplied, the other temperature is calculated to meetthe enthalpy balance. If both temperatures are given, duty is calculated.

Temperature specifications may be a temperature value, the temperaturerise above the feed, dew or bubble point or an approach to dew orbubble point.

Stream CreationIn order to define the pseudoproduct, specifications must be entered inthePseudoproduct Specificationswindow to define how much of eachcomponent is in the product. Specifications may be on single compo-nents or on ranges of contiguous components and several specificationsmay be required. At least one specification must be defined. Anycomponent which does not appear in a specification will be set to zeroin the pseudoproduct. If the unit has feeds, component rates, recoveryor composition in the product may be specified, Otherwise, thecomponent rates must be defined.

If there is no feed to the unit, pseudoproduct thermal condition must bedefined in thePseudoproduct Conditionswindow. If there is a feed, thetemperature and pressure specifications are optional. The pressuredefaults to lowest feed pressure and the temperature is calculated tosatisfy the enthalpy balance. If a duty is supplied, it will be used onlyfor the stream splitting enthalpy balance. Duty is not used for the pseu-doproduct enthalpy balance.

Temperature specifications may be a temperature value, the temperaturerise above the feed, dew or bubble point or an approach to dew orbubble point. If there is no feed, the temperature rise specificationcannot be used.


Negative Component RatesIt is possible to specify the unit such that negative component rates arecalculated in a product stream. The appropriate action if this happensis selected from:

● reset any negative rates to zero (this is the default)

● reset the rates to their absolute value

● the unit should fail.

Thermodynamic SystemThe thermodynamic system of methods to be used for the stream calcu-lator may be selected by choosing a method from theThermodynamicSystemdrop-down list box on theStream Calculatormain data entrywindow.


SPEC/VARY/DEFINEGeneral InformationPRO/II has an extensive system of cross-referencing for flowsheetparameters. Flowsheet parameters include operating conditions for unitoperations, calculated results from unit operations, and stream flows,compositions, and properties. For example, the supplied outlet pressurefor a Pump, the calculated temperature for a dew pointFlash, and thesimulated D86 ninety-five percent distilled temperature for aColumnproduct stream are all flowsheet parameters.

Most unit operation parameters may be eitherDEFINEdor SPECifiedrelative to any other flowsheet parameter in the problem. Some unitoperations mayVARYa flowsheet parameter that would ordinarilyremain constant at the input value. The table below summarizes themethods for cross-referencing flowsheet parameters:

SPEC: A unit operation or stream performance specification (calculatedresult) must meet a desired value, either on an absolute basis or relativebasis.

VARY: A unit operation or stream flowsheet parameter is varied fromthe supplied value.

DEFINE: A unit operation parameter is defined by cross-reference toanother flowsheet parameter.

PRO/II uses a common format for theSPECification, VARY,andDEFINE features. Each feature is discussed separately below. Tablesare also presented with cross-reference availabilities of the flowsheetparameters for streams and the unit operations.

SPECificationsBy definition, aSPECificationmust always be a calculated flowsheetresult. The following unit operations use the generalizedSPECformatto define the performance of the unit:Flash, Splitter, Column/SideColumn,andController.

A SPEChas the following general form:

Parameter= valuewithin the default tolerance

A choice for the Parameterand a numeric entry for the valuemust besupplied by clicking on the underlined hypertext strings to gain accessto the pertinent data entry fields. Optionally, the tolerance basis may bechanged from the default toabsoluteor relativeand the defaulttolerance value of 0.02 replaced by direct entry.


➤ Click on the Parameterhypertext to access theParameterwindow.

➤ Choose the Stream or Unit from the drop-down list box.

➤ Select the unit or stream name in the drop-down list box.

➤ Finally, click on the Parameterhypertext and select the desired pa-rameter from the window that is displayed. Note that only thoseunit or stream parameters that are valid for use as a SPEC are avail-able.

If the SPEC is not related to another flowsheet parameter:

➤ Click OK to return to the unit specification.

➤ Click on the valuehypertext, and enter the desired numeric valuefor the SPEC.

To create a mathematical expression for the SPEC:➤ Select the =sign linked text and select an option from the pop-up

window. Choices are as follows:

No Operator:

Primary parameter only (the default)

+ Operator :

Primary parameter plus reference parameter(SUM)

- Operator :

Primary parameter minus reference parameter(DIFFERENCE)

/ Operator :

Primary parameter divided by reference parameter (RATIO)

x Operator :

Primary parameter times reference parameter (TIMES)

➤ Select theReference Parameterand click on the Parametertextstring, and select the desired reference parameter from the listwhich is displayed.

Note: Only those unit or stream parameters which are valid for aspecification are available.


➤ Click the OK button to return to the unit specification window;then click on the valuelinked text string to enter the desired nu-meric value for the SPEC.

The following examples illustrate the use of SPECs:

Example 1: Reid Vapor Pressure of stream S103 = 6.0

Unit or stream parameter = a value within a relative tolerance of 0.02| || [6.0]

SpecificationUnit/Stream Stream Name {Parameter Window}

[Stream] [S103]Parameter

[Vapor Pressure]

Example 2: Duty of exchanger X103/ Duty of exchanger X104 = 1.0+ 0.001

Unit or stream parameter = a value within a relative tolerance of 0.02| | | || [1.0] [absolute] [0.001]

SpecificationUnit/Stream Unit Name {Parameter Window}

[Heat Exchanger] [X103]Parameter

[Duty]Reference: [/ Parame-ter =]Reference Parameter

Unit/Stream Unit Name {Parameter Window}[Heat Exchanger] [X104]

Parameter[Duty]

Note: [ ] denotes user input.

VARYsFor eachSPECin a flowsheet, there must be oneVARYor degree offreedom. TheVARYfor theFlashunit is implicitly defined, i.e., notdefined explicitly by the user. ForFlashunits with specifications, thedegree of freedom is the temperature when the pressure or pressure drop isgiven and the pressure when the temperature is supplied. Other unit opera-tions which haveVARYsare theColumn/Side Columnand theController.A VARYis always a flowsheet parameter that has afixedversus calculatedvalue in the flowsheet.


For Columns/Side Columnsa VARYmay be a feed stream rate, productdraw rate, or a heat duty. For example, the lean oil feed rate to acolumn may be defined as aVARYin order to meet a specification onthe propane recovery for the column. Ordinarily, the lean oil feed ratewould have a fixed or constant rate in the flowsheet.

ControllershaveVARYsthat are associated with other unit operations.For example, the supplied outlet pressure for aCompressormay be aVARYfor a Controller. Note that this flowsheet parameter would ordi-narily have a fixed or constant value in the flowsheet. On the otherhand, the calculated temperature for a dew pointFlashunit could notbe used as aVARY, since this is a flowsheet parameter that is deter-mined by the flowsheet calculations.

A VARYhas the following general form:

Vary Parameter

To enter a parameter:

➤ Click on the underlined hypertext string to access theVariablewin-dow.

➤ From this window, select the type of vary, i.e., stream or unit type,in the drop-down list box.

➤ Next, select the unit or stream name in the adjacent drop-down listbox.

➤ Finally, click on the Parameterhypertext string and select the de-sired parameter to be varied from the list.

Note: Only those unit or stream parameters which are valid for use asa VARY are available.

The following example illustrates the use ofVARYs:

Example 3: The temperature for isothermal flash unit D101 isvaried by a Controller.

Vary unit or stream parameter ||

SpecificationUnit/Stream Unit Name {Variable Window}[Flash] [D101]Parameter[Temperature]

Note: [ ] denotes user input.


DEFINETheDEFINE is used to dynamically define the value for a flowsheetparameter that ordinarily has afixedversus calculated value in theflowsheet. Thus, the value for a unit operating condition may be set toa value that is based on acalculatedflowsheet parameter. For example,theDEFINE may be used to set the temperature for an isothermalFlashto the temperature that is calculated for aCompressoroutlet streamplus 10 degrees. This concept greatly enhances the flowsheeting capa-bility of PRO/II, and, in fact, nearly every unit operation inputparameter may beDEFINEd in PRO/II.

To define a flowsheet parameter:➤ Select the parameter in the appropriate window for the unit opera-

tion. At this point the Define button on the toolbar is activated ifthe parameter may be DEFINEd. Click theDefine button to ac-cess the Definition window.

➤ From this window, select the check box to enable theDEFINEoptions.

➤ Click on the Parametertext string and select the desired parameterfrom the window which is displayed.

Note: Only those unit or stream parameters which are valid for use asa DEFINE are available.

➤ If the DEFINE is not related to another flowsheet parameterclick OK to return to the unit window. If theDEFINE is related toanother flowsheet parameter, establish the appropriate mathemati-cal relationship. Mathematical expressions for aDEFINE are cre-ated in a manner completely analogous to that described above onpage 9-136 for aSPEC.

➤ Select the reference parameter type in the same manner as used toselect the primary parameter.

➤ Click the OK button in the child windows to return to the unit op-eration window.

For a constant:

➤ SelectConstantfrom theConstant/Stream/Unitdrop-down list boxin theParameterwindow.

➤ Enter a numerical constant in the supplied data entry field.


The following example illustrates the use of a DEFINE:

Example 4: DEFINE the temperature for Flash drum D103 tobe the temperature of stream S104 minus 15 degrees.

[Select the temperature field on the Flash Second Specification][Push the Define button on the Toolbar][Select the check box to set up the Define]

|Primary Parameter:

Unit/Stream/Constant Unit Name {Definition Window}[Stream] [S104]Parameter

[Temperature]Reference: [= Parameter - Parameter]

Reference Parameter:Unit/Stream/Constant Value

[Constant] [15.0]

Note that theDEFINE is nearly identical in structure to theSPEC.

Stream Parameters Available for Cross-Referencing

��SPECS�� DEFINE1 VARY2

Parameter Flash Splitter Column Controller All Units Controller

Temperature Yes - Yes Yes Yes Yes

Pressure Yes - Yes Yes Yes Yes

Enthalpy Yes - Yes Yes Yes -

Mole Weight Yes - Yes Yes Yes -

Total Flow Yes Yes Yes Yes Yes Yes

Component Flow Yes Yes Yes Yes Yes -

Composition Yes - Yes Yes Yes -

Phase Fraction Yes - - Yes Yes -

Density/Volume Yes - Yes Yes Yes -

Distillation Curve Yes - Yes Yes Yes -

Vapor Pressure Yes - Yes Yes Yes -

Transport Property Yes - Yes Yes Yes -

Refining Property Yes - Yes Yes Yes -

Special User Property Yes - Yes Yes Yes -

1 In general, any applicable stream property may be used to define a unit operating condition. Note that notall stream properties are applicable to all unit operating conditions.

2 With the exception of the Column, only the Controller may vary stream parameters. The Column mayvary the total flow of a feed strean.


Unit Parameters Available for Cross-Referencing

Within Operation External Controllers

Unit Parameter SPEC VARY DEFINE Reference1 SPEC VARY

Calculator

Result - - Yes Yes Yes Yes

Parameter - - Yes - - -

Stream Calculator

Temperature - - Yes - - Yes

Pressure - - Yes - - Yes

Delta T - - Yes - - Yes

Temp. Below Bubble Pt. - - Yes - - Yes

Temp. Above Dew Pt. - - Yes - - Yes

Delta P - - Yes - - Yes

Feed Cofactor - - Yes - - Yes

Duty - - Yes Yes - Yes

Frac. Overhead - - Yes - - Yes

Frac. Bottoms - - Yes - - Yes

Frac. Product - - Yes - - Yes

Overheat Rate - - Yes - - Yes

Bottoms Rate - - Yes - - Yes

Product Rate - - Yes - - Yes

Comp. Overhead - - Yes - - Yes

Comp. Bottoms - - Yes - - Yes

Comp. Product - - Yes - - Yes

Controller

Specification - - - - - Yes

MVC


Optimizer


Constraint - - - - - Yes

Column

Reflux Yes - - Yes Yes -





Reflux Ratio Yes - - Yes Yes -

Duty Yes Yes Yes Yes Yes Yes

Feed Rate - Yes - - - Yes

Draw Rate - Yes - - - -


Percent of Flood - - - Yes Yes Yes

Max % of Flood - - - Yes Yes -

Downcomer B/U - - - Yes Yes Yes

Max D.C. B/U - - - Yes Yes -

CS Approach - - - - Yes -

Flood Approach - - - - Yes -

Tray Diameter - - - Yes Yes -

Max Tray Diam. - - - Yes Yes -

Condenser Pres - - Yes - - Yes

Top Tray Pres - - Yes - - Yes

Tray Delta P - - Yes - - Yes

Column Delta P - - Yes - - Yes

Tray Temp Yes - - Yes Yes -

Feed Tray No - - - Yes - Yes

Draw Tray No - - - Yes - Yes

Duty Tray No - - - Yes - Yes

Tray Effy Factor - - Yes Yes - Yes

P/A Rate - - Yes - - Yes

P/A Return T - - Yes - - Yes

Product Moles - - Yes - - -

Thermosiphon Reboiler

Circulation Rate - - Yes Yes - Yes

Vapor Fraction - - Yes Yes - Yes

Liquid Fraction - - Yes Yes - Yes

Outlet Temp - - Yes Yes - Yes





Delta T - - Yes Yes - Yes

LLEX


Top Tray Pres - - - - - Yes

Feed Rate - Yes - - - Yes

Draw Rate - Yes - - - Yes

Duty - Yes - - - Yes

Pump

Temperature - - - Yes Yes -

Outlet Pres - - Yes Yes Yes Yes

Delta P - - Yes Yes Yes Yes

Pres. ratio - - Yes Yes Yes Yes

Work - - - Yes Yes -

Head - - - Yes Yes -

Efficiency - - Yes - - Yes

Pipe

Diameter - - Yes Yes Yes Yes

Max velocity - - Yes Yes Yes Yes

Average velocity - - - Yes Yes -

Delta P - - - Yes Yes -

Duty - - Yes Yes Yes Yes

Rel Roughness - - Yes Yes - Yes

Abs Roughness - - Yes Yes - Yes

Friction Factor - - Yes Yes - Yes

Flow Efficiency - - Yes Yes - Yes

Length - - Yes Yes - Yes

Heat Transfer Coeff. - - Yes Yes - Yes

Ambient Temp - - - - - Yes

Delta P Max - - - - - Yes

K-Factor - - Yes - - Yes





Simple Exchanger


Cold Delta P - - Yes Yes Yes Yes

Cold T Out - - Yes Yes - Yes

Cold Liq Fr - - Yes - - Yes

Cold Subcool - - Yes - - Yes

Cold Sup�heat - - Yes - - Yes

Hot Delta P - - Yes Yes Yes Yes

Hot T Out - - Yes Yes - Yes

Hot Liq Fr - - Yes - - Yes

Hot Subcool - - Yes - - Yes

Hot Sup�heat - - Yes - - Yes

LMTD - - - Yes Yes -

Zoned LMTD - - - Yes Yes -

Overall U - - Yes Yes Yes Yes

Area - - Yes Yes Yes Yes

U * Area - - Yes Yes Yes Yes

Ft Factor - - Yes Yes Yes Yes

Approach - - Yes Yes Yes Yes

MITA (Pinch) - - Yes - - Yes

Min. Approach - - Yes Yes Yes Yes

Rigorous Heat Exchanger

Duty - - - Yes Yes Yes

Overall U - - - Yes Yes -

Estimated U - - - - - -

Area - - Yes Yes Yes Yes

U*Area - - Yes Yes Yes -


Shell T Out - - Yes Yes Yes Yes

Tube T Out - - Yes Yes Yes Yes





Tube Foul Factor - - Yes Yes Yes Yes

Shell Foul Factor - - Yes Yes Yes Yes

Required Foul Factor - - Yes Yes Yes -

LNG Heat Exchanger

Duty - - - Yes Yes -

T Out - - Yes Yes Yes Yes

Single Stream Duty - - Yes Yes Yes Yes

Delta P - - Yes Yes - Yes

U*Area - - - Yes Yes -


MITA - - - Yes Yes -

Splitter

Temperature - - Yes Yes Yes -

Pressure - - Yes Yes Yes Yes



Valve

Temperature - - - Yes Yes -



Compressor

Outlet Temp - - Yes Yes Yes Yes



Compr. Ratio - - Yes Yes Yes Yes

Actual Work - - Yes Yes Yes Yes

Head - - Yes Yes Yes Yes

Adiab. Effy - - Yes Yes Yes Yes

Poly Effy - - Yes Yes Yes Yes





Max. Press - - Yes - - Yes

Cooler DP - - Yes - - Yes

Cooler Temp - - Yes - - Yes

Temp Estimate - - Yes - - -

RPM - - Yes Yes - Yes

Curve RPM - - Yes Yes - Yes

Expander

Outlet Temp - - - Yes Yes -


Pressure Drop - - Yes Yes Yes Yes

Expans. Ratio - - Yes Yes Yes Yes

Actual Work - - Yes Yes Yes Yes


Adiab. Effy - - Yes Yes Yes Yes

Min. Pressure - - Yes - - Yes

Flash

Temperature - - Yes Yes Yes Yes





Entrainment - - Yes - - Yes

Pseudo Prod. - - Yes - - -

Mixer

Temperature - - - - Yes -








Pump

Temperature - - Yes Yes Yes -



Press Ratio - - Yes Yes Yes Yes

Work - - - Yes Yes -


Efficiency - - Yes - - Yes

Equilibrium Reactor





Conversion - - Yes Yes Yes Yes

Stoic. Coeff. - - Yes - - -

Conversion Reactor





Conversion - - Yes Yes Yes Yes

Gibbs





PFR







Delta P - - - Yes - Yes

Inlet Pres. - - - Yes - Yes

Delta P In - - - Yes - Yes


Tube Diameter - - - Yes - Yes

Length - - - Yes - Yes

No. of Tubes - - - Yes - Yes

U - - Yes - Yes

Max Veloc. - - Yes Yes Yes -

Temp In - - Yes Yes Yes -

Temp Out - - - Yes - Yes

Pre-exp. Factor - - - Yes - Yes

Activation E - - Yes - - Yes

Conversion - - Yes Yes Yes -

CSTR/Boiling Pot





Conversion - - - Yes Yes -

Pre-exp factor - - Yes Yes - Yes

Activation E - - Yes Yes - Yes

Volume - - Yes Yes - Yes

Min. Temp. - - Yes - - Yes

Max. Temp. - - Yes - - Yes

Max. Veloc. - - Yes - - Yes

Depressuring

Final Pres. - - Yes Yes Yes Yes

Relief Pres. - - Yes Yes - Yes

Final Time - - Yes Yes Yes Yes





Relief Time - - Yes Yes - Yes

Relief Duration - - Yes Yes Yes Yes

Valve Constant - - Yes Yes - Yes

Valve Back P. - - Yes Yes - -

Valve Coeff. - - Yes Yes - Yes

Critical Flow Factor - - Yes Yes - Yes

Init. Wetted A - - Yes Yes - Yes

HT Area - - Yes Yes - Yes

HT Coeff - - Yes Yes - Yes

HTC Fac - - Yes Yes - Yes

Vapor HTC - - Yes Yes - Yes

Liquid HTC - - Yes Yes - Yes

Coeff C1 - - Yes Yes - Yes





Final Temp - - - Yes Yes -

Final Duty - - - Yes Yes -

Final Vent Rate - - - Yes Yes -

Vess. Vol. - - Yes Yes - -

Liquid Holdup - - Yes Yes - -

Vess. Diam. - - Yes Yes - -

Vol. Corr. Fac. - - Yes Yes - -

Ht. of Holdup - - Yes Yes - -

Vess Weight - - Yes Yes - -

Vess. CP - - Yes Yes - -

Tan-tan Vess. Length - - Yes Yes - -

Tan-tan Vess. Height - - Yes Yes - -

Time Step - - Yes Yes - -





Isen Eff. - - Yes Yes - Yes

Heat Scal. Fac. - - Yes Yes - Yes

Area Scal. Fac. - - Yes Yes - Yes

1 Available for any SPEC or DEFINE.


USER-ADDED UNIT OPERATIONSGeneral InformationThe PRO/II User-added Unit Operation capability enables users to addtheir own FORTRAN subroutines to simulate any type of unit operationor to perform calculations on flowsheet parameters. The subroutinemust first be linked into the PRO/II program and it is then accessed viathe graphical user interface in the same way as any other unit operation.

The User-added Unit Operation has access to the PRO/II physicalproperty data and may call the PRO/II flash and property calculationsubroutines. Other information, such as input and output dimensionalunits, is also available. See thePRO/II Data Transfer System andUser-Added Subroutine User’s Guidefor information on writing and inter-facing User-Added Unit Operation subroutines.

The developer of the User-added Unit Operation can also customize theUser-added Unit Operation Data window to request only data whichmay be required for the calculations.

Note: If transport properties are required in the User-added Unit Op-eration, you must select a suitable method in the Thermodynamic Data.

Selecting the SubroutineWhen a User-added Unit Operation is laid down on the PFD, theUser-added Unit Operationwindow opens in which the user must select thename of the required subroutine.

Calculation or Output ExecutionA User-added Unit Operation may be executed during the flowsheetconvergence calculations or at output time only. TheUser-added UnitOperation Datawindow will show when the selected subroutine iscalculated. This affects whether feeds and/or products are allowed.

The default is to perform the calculations for the user-added unit as partof the normal flowsheet convergence calculations.

Calculation time: The User-added Unit Operation is calculated as part ofthe normal flowsheet convergence. Additional calculations may beperformed at output time and an output report may be produced.

Output time: If the User-added Unit Operation requires only convergedflowsheet data for calculations and reports, it can be executed at outputtime rather than during the flowsheet convergence.


Feeds and ProductsThe User-added Unit Operation may have up to ten feed streams. Thesubroutine can retrieve each feed separately. They are not mixed orflashed. If they are to be mixed, the user must do this in the subroutine.User-added Unit Operations which are to be executed during theflowsheet convergence must have at least one feed stream. Thosewhich are only executed at output time need not have any feeds.

User-added Unit Operations which are to be executed during theflowsheet convergence may have up to ten product streams. These maybe any combination of phases. User-added Unit Operations which areonly executed at output time cannot have any product streams.

Stream ReorderingIf the User-added Unit Operation has more than one feed or product,they will be shown in the order in which they were laid down on thePFD. The user may need to reorder the streams so that they arepresented in the correct order to the User-added Unit Operation. Forexample, the User-added Unit Operation may always feed vapor to thefirst product stream and liquid to the second.

Reordering is done in theUser-added Subroutine - Stream Reorderingwindow accessible by clicking theReorder Streams button on theUser-added Unit Operation Datawindow.

Entering DataData are supplied to the User-added Unit Operation in four tables:

● Real Data

● Supplemental Data

● Integer Data

● Heat Balance Data

Data can be supplied to a User-added Unit Operation using either a“Customized Data Entry Window” or the standard “Developers DataEntry Window.” These two choices are explained below.

Data may also be entered into the variables in the Real Data table usingthe PRO/II Define feature.

The variables in the Real Data table are also available to other unitoperations by means ofSPECs, VARYsandDEFINEs. The other tablesare used solely by the User-added Unit Operation.


�Customized� Data Entry WindowA user has the option of defining a “Customized Data Entry Window”to be used for all user-added unit operations that utilize a specific user-added calculation subroutine. The standard PRO/II User-added UnitOperations use the default names USER41 - USER60 (displayed asUS1-US20). If you create a customized data entry window for a user-added calculation subroutine, the name that is selected for it willreplace one of the default names in the list of available subroutinenames that is displayed when a user-added unit is laid down on thePFD.

Creating a �Customized� Data Entry WindowTo create a customized data entry window to be used for a specificuser-added calculation subroutine, two ASCII files must be created inthe directory specified by the “UserConfigDir= entry in thePVISION.INI file. These two files are called UASLIST.INI andUSERXX.INI and are described below.

File UASLIST.INIThis file contains the user-specified names for specific user-addedcalculation subroutines that will be displayed in place of the default namesUS1 - US20, corresponding to the subroutines USER41 - USER60.Eachline in the file has two entries; the entry number in the list of user-added subroutine names, and the actual text that is to be displayed forthe user-added subroutine. An example of a typical UASLIST.INI fileis shown below:

1 PIPE DP Routine2 Stream Heating Value

These entries in the UASLIST.INI file will result in the following list ofavailable user-added calculational subroutines being displayed when aUser-added Unit Operation is laid down on the PFD:


User-added Operation Window

File USERXX.INIThis file contains the variable names and array locations for all of theReal, Supplemental, Integer, and Heat Balance Data values that thespecific user-added calculation subroutine requiresor that can beinput by the user. For a user-added subroutine with a customized dataentry window, a user will only be able to enter values for the data itemsspecified in this file. The “XX” in the name of the USERXX.INI filecorresponds to the respective user-added subroutine referenced, i.e. theuser-added subroutine USER41 with a user-specified name of “PIPEDP Routine” above would need a “USER41.INI” file to describe therequired data for the calculations. An example of a typicalUSERXX.INI file is shown below:

Example USER41.INI file:

IPARM 1 �Print Control� Required

RPARM 1 �Diameter (in)� Required

RPARM 2 �Length (ft)� Required

...

SUPPLE 1 �No. Of Segments� Required

...

The first entry on each line indicates to which data array the variablebelongs. The second entry is the array number where the data valueentered by the User will be stored for access by the User-added calcula-tional subroutine.

The third entry is the label to be displayed for the variable in thecustomized data entry window.This entry must be enclosed indouble quotes (“”).


The fourth entry on each line indicates whether or not data entry for theitem is Optional or is Required. The default is Optional, and this entryis not required.

The entries in the USER41.INI file shown above will result in thefollowing required data values and variable names being shown in thecustom window displayed for data entry, for any User-added UnitOperation where the user-selected “PIPE DP Routine” as the user-added subroutine when the unit was laid down on the PFD as shownbelow.

Customized UAS Data Entry Window

The order in which the variable labels appear on the customized User-added Unit Operation Data window is the same as the order in whichthey appear in the USERXX.INI file.

The limits on the number of variables that can be entered for each arrayare shown below. These limits are:

● Real Data - up to 500 elements

● Supplemental Data - up to 10,000 elements

● Integer Data - up to 250 elements

● Heat Balance Data - up to 10 elements


Each table shows the name(s) of the variable(s) for which values mustbe entered. They will scroll if they contain more than four rows. Alldata entries displayed using a customized data entry window arerequired. No checks on validity or completeness of the data are carriedout until the User-added Unit Operation is executed.

The Standard Developer�s Data Entry WindowA special window is available for developers of User-added UnitOperations. It is the default window displayed for a User-added UnitOperation if a “Customized Data Entry Window” has not been definedfor the specific unit.

The developer’s data entry window has no variables names and anynumber of variables may be entered up to the limits of each array.These limits are:

● Real Data - up to 500 elements

● Supplemental Data - up to 10,000 elements

● Integer Data - up to 250 elements

● Heat Balance Data - up to 10 elements

The user must know which elements of each array are used by theUser-added Unit Operation and enter the array element number alongwith the value. Values may be entered for any or all of the elements inthe arrays. The elements defined need not be contiguous and may beentered in any order.

PRO/II knows nothing about the data requirements of a User-addedUnit Operation and so no restrictions are imposed in the data entry.

Note: Unless the user defines a custom Data Entry Window for a speci-fied User-added Unit Operation, the data entry for that unit will be viathe developers data entry window.


ELECTROLYTE MODULEGeneral InformationThe optional Electrolyte Module of PRO/II allows you to handlesystems containing electrolytes. See thePRO/II Add-On ModulesUser’s Guidefor more information. The following unit operations canbe used with this electrolyte version:

● Flash

● Pump

● Valve, Mixer, Splitter

● Pipe

● Simple heat exchanger, LNG heat exchanger

● Conversion reactor, Equilibrium reactor

● Stream calculator

● Heating/Cooling curve

● Calculator

● Controller, Optimizer

● Column (Electrolytic Algorithm, see below)

Thermodynamic ModelsEight built-in electrolyte models in PRO/II simulate aqueous systems ina wide range of industrial applications. The models apply to fixedcomponent lists with a predefined set of thermodynamic methods forK-values, enthalpies and densities. It is not possible to define indi-vidual methods for K-value, enthalpy or density when using electrolytethermodynamic models.

Note: Electrolyte models may not be used to calculate the followingproperties: (1) Non-aqueous electrolyte systems; (2) Free water de-cant; (3) Water dew points; (4) Hydrocarbon dew points, (5) Entropyand heat capacity.

The following electrolyte models are available in this release:

● Amine Systems

● Acid Systems

● Mixed Salt Systems

● Sour Water Systems

● Caustic Systems


● Benfield Systems

● Scrubber Systems

● LLE and Hydrate Systems

To select an electrolyte model:➤ Click on the Themodynamic Data button on the toolbar to open the

Thermodynamics Datamain data entry window.

➤ Select theElectrolyteoption in the Category list box.

➤ Choose an appropriate electrolyte model.

The suggested range of applicability for the electrolyte models issummarized below:

Temperature: 32-390 F (0-200 C)

Pressure: 0-200 atm

Dissolved gases: 0-30 mole %

Ionic solutes: 0-30 ionic strength

Amine Systems

Pressure: 0-30 atm

LLE Systems

Organic solutes: 0-10 weight %

You may add your own models, specifically suited to your application, byusing the PRO/II and the Electrolyte Utility Package (EUP). If you wish todo this, contact your nearest SIMSCI support office for more information.

Note: Take care when using non-electrolyte and electrolyte thermody-namic methods in the same application. The PRO/II electrolytic modelsuse a different enthalpy basis from that used for other thermodynamicsystems. When both are used, PRO/II automatically takes care of thedifference but it may appear to be confusing. To avoid this, select theelectrolyte enthalpy method for all non-electrolyte thermodynamic sys-tems in a mixed application. All systems will then use the electrolytemodel basis.

Electrolytic Column Algorithm (ELDIST)This column algorithm was designed to solve non-ideal aqueous elec-trolytic distillation columns involving ionic species. It uses a Newton-Raphson method to solve the mass balance, vapor/liquid equilibrium


and specification equations simultaneously. The K-values and enthal-pies are supplied by the electrolyte thermodynamic model.

The Electrolytic Column Algorithm is selected from the ColumnAlgorithm drop-down list box on the Column main data entry window.

Note: Electrolytic thermodynamic models only support VLE and sototal phase draws are not permitted.

Advantages and disadvantages of the Electrolytic Column Algorithmare given below:

Advantages (1) Rigorously models ionic equilibrium systems.(2) Solves highly non-ideal distillation columns.

Disadvantages (1) Side columns are not supported.(2) Pumparounds and tray hydraulics are not

available.(3) Certain Column Specifications and Variables

are not permitted.


SIMSCI ADD-ON MODULESAdd-on modules can be obtained in this version of PRO/II to extend thefunctionality of the program. These modules include units for modelingpolymer systems, separating solid components from feed streams, blendingstreams with different component and refinery inspection properties, aswell as Profimatics hydrotreating and reformer reactor models.

SIMSCI POLYMER CSTR Unit OperationPRO/II contains features for handling polymers (e.g., van Krevelenproperty prediction method, polymer moment attributes, ALM thermo-dynamic method, and polymer flash).

The SIMSCI Polymer CSTR Add-on Model offers you the capability ofmodeling a polymerization reactor operating under the followingconditions:

● Single monomer producing a linear homopolymer.

● Single phase reaction (effects of heat and mass transfer on themass transport are not considered).

● Ideal CSTR (steady-state, well mixed, constant volumereactor).

● Free radical polymerization kinetics.

● Bulk or solution polymerization.

This reactor unit has been added to PRO/II as part of the SIMSCIAdd-on Models (Polymer CSTR) and is available from SIMSCI as theSIMSCI Polymer CSTR module.

Required Data for the Polymer Reactor UnitThis version of PRO/II does not allow you to enter the necessaryComponent, Stream, or Thermodynamic Data via required the dataentry windows. However, you can enter the necessary Polymer CSTRdata using the Polymer CSTR data entry window for the SIMSCIAdd-on Model.

To enter data for the Polymer CSTR:

Once you have entered your simulation data, including the data for thePolymer CSTR, but excluding any polymer-specific thermodynamic,stream, or component data, you will need to do the following:

➤ Export the simulation data to a PRO/II keyword file.

➤ Add the necessary polymer-specific data to the keyword file.

➤ Import the modified keyword file into PRO/II and run the simula-tion problem in Run-Only mode.


For additional information, refer to thePRO/II Add-On Modules User’sGuide.

SIMSCI COMPONENT PROPERTY REPORTER Unit OperationThis unit prints out the Component Properties and Refinery InspectionProperties for all the thermodynamic methods in the current flowsheet.This unit is selected from a drop-down list box on the SIMSCI Add-onUnits main data entry window. No data input is required.

SIMSCI BLEND Unit OperationThe Blend unit allows you to blend two or more streams to give oneproduct stream with different component and refinery inspection prop-erties. This unit is selected from a drop-down list box on the SIMSCIAdd-on Units main data entry window.

The feed streams should have different thermodynamic methods for thisunit to function correctly, but this is not necessary. The unit thermody-namic method must be different from any of the feed stream thermody-namic methods.

The following data must be provided:

● Product stream temperature.

The product stream pressure may also be supplied, but if it is not given,the pressure will be set to the lowest feed stream pressure.

The unit thermodynamic method component properties will be recalcu-lated from the blend of the feed streams properties and will then bestored as part of that thermodynamic method data storage. Onlypetroleum and assay generated component properties will be recalcu-lated; it is assumed that Library component properties do not change inthe flowsheet. The unit first recalculates the normal boiling point,molecular weight and specific gravity for all the petroleum compo-nents. These recalculated properties are then used to re-characterize allthe other petroleum fraction properties such as the critical temperature.

Using the Blend Unit with Refinery Inspection PropertiesAny refinery inspection properties specified in the input will also beblended from the feed streams properties using the specified blendingmethod for that property. It is necessary that every thermodynamicmethod must have the same refinery inspection properties specified andthat these properties must use the same property method and blendingbasis in order for the unit to work. A check is done at input time tocheck that all the methods in the problem have the same refinery prop-erties, methods and bases specified. You can request this check to be


done at calculation time on the methods used in the current unit usingthe IPARM entry.

Note: Requesting this check at calculation time should be used withcare and is not recommended.

SIMSCI RESET Unit OperationThe RESET unit allows you to reset the product stream enthalpy datumusing the thermodynamic method specified within the unit. This unit isselected from a drop-down list box on the SIMSCI Add-on Units maindata entry window. Only one feed and one product stream are allowedfor the unit.

Note: If you try to import a keyword file that specifies more than onefeed or product stream, PRO/II will produce an input error.

The feed stream pressure is always kept constant and you are requiredto specify whether the temperature, enthalpy, dew point, bubble point orvapor fraction is kept constant. The new product stream conditions willbe calculated based on the option specified. The available calculationoptions are entered through the first value in the Integer Data for Unitfield and are as follows:

Value Entered Calculation Option

1 Specify the product stream at the feed stream temperature

2 Specify the product stream at the feed stream enthalpy

3 Specify the product stream at the dew temperature

4 Specify the product stream at the bubble temperature

5 Specify the product stream at the feed stream vapor fraction

Note: In this version, a warning message will alert you if the thermody-namic method of the unit operation is different from the thermodynamicmethod of any of the feed streams. This warning message applies to allunit operations except for the RESET unit, the BLEND unit and anyProfimatics reactor models.

SIMSCI Profimatics Reactor Unit OperationsThese units model Profimatics Hydrotreater and Reformer Reactor unitoperations and can be selected from a drop-down list box on theSIMSCI Add-on Unitsmain data entry window.


VALVEGeneral InformationTheValveis used to model the Joule-Thompson effect that occursacross a pressure restriction such as a valve, orifice plate, etc. Thetemperature for the exit fluid is computed by assuming that theoperation is adiabatic. Rigorous calculations may be performed forboth VLE and VLLE systems.

Feeds and ProductsA valve operation may have multiple feed streams, in which case theinlet pressure is assumed to be the lowest feed stream pressure.

A valve may have one or more product streams. The product phasecondition for valve operations withoneproduct stream is automaticallyset by PRO/II. For valve units with two or more product streams, theproduct phasesmustbe specified in theValve Product Phaseswindowwhich is accessed by clicking theProduct Phases… button on theValvemain data entry window.


Outlet ConditionsThe outlet condition for a valve is selected with the appropriate radiobutton on theValvemain data entry window as:

Pressure dropOutlet pressure

Thermodynamic SystemThe thermodynamic system of methods to be used for valve calcula-tions may be selected by choosing a method from theThermodynamicSystemdrop-down list box on theValvemain data entry window.


WIPED FILM EVAPORATORGeneral InformationTheWiped Film Evaporatorunit operation (WFE) provides the capa-bility to model the separation of solvents and/or monomers from apolymer melt. AWiped Film Evaporatorshould be used when theremoval of volatiles from a viscous polymer melt is diffusion limited.The blades inside the wiped film evaporator continually mix and spreada thin film of the melt on the wall of the evaporator. As the melt movesdown the evaporator, the volatiles diffuse out of it and into the vaporspace of the evaporator. The volatiles are pulled out of the evaporatorunder vacuum.

Detailed InformationFor detailed information regarding operating modes, data requirements,and range of applicability of theWiped Film Evaporatormodel, consultthePRO/II Add-On Modules User’s Guide.


Chapter 10Running and Viewing a Flowsheet

This chapter describes how to run a simulation, interactively change thecalculation sequence, use breakpoints, and view calculation history andresults.

Using the Run PaletteThe PRO/II Run palette shown in Figure 10-1 provides options for dataverification, interaction with the simulation (running the simulation bystepping through the units) and viewing convergence or simulationresults. You access these features by choosing the appropriate button onthe Run palette. If all required input data have not been provided whenyou choose theRun button, PRO/II will display a warning messagetelling you which data are incomplete.

To display/hide the Run palette:

➤ Select/deselect theView/Palettes/Runoption from the menu bar.The Run palette appears/disappears on the PRO/II main window.

Figure 10-1: Run Palette

PRO/II User's Guide Chapter 10 Running and Viewing a Flowsheet10-1

The palette displays push buttons that execute or access a feature:

Operation Description

Status Displays the global messages for the current simulation.

Check Data Checks the input data to determine whether there are any datainconsistencies.

Run Executes the simulation, either from the beginning or from abreakpoint. �Check Data� is automatically performed, if neces-sary.

Step Steps through the execution of the simulation by stopping ateach unit operation in the calculation sequence.

Stop Interrupts or stops the simulation while it is executing. The pro-gram completes its current calculation before stopping.

SetBreakpoints

Selects the units you want to assign as breakpoints. The pro-gram then executes the simulation, stopping at these break-points.

Goto Starts the execution from any specified unit. You can select theunit by clicking the �Goto cursor� on the desired unit in theflowsheet.

Messages Displays the calculation history as it is being produced. Thiswindow can be displayed when the PRO/II calculation engine isexecuting the simulation, in which case, the history will be up-dated as the calculation proceeds.

View Results Displays the detailed output results of the highlighted unit op-eration or stream in the flowsheet of the previously run simula-tion. You can review the results of multiple units or streams, ifdesired. If the simulation has been run previously, you can viewits results without executing it again by opening the appropriate.OUT file.

ShowBreakpoints

Shows which units are assigned as breakpoints by displayingtheir icons in a different color. Clicking the button a second timedisables the breakpoint display.

Chapter 10 Running and Viewing a Flowsheet PRO/II User's Guide10-2

Checking the Simulation StatusUse the Status button to display theFlowsheet Statuswindow. Thiswindow allows you to view the global status messages for the currentsimulation. This button is highlighted as a selectable operation only ifCheck Datahas been previously invoked either directly from the palette orindirectly from execution of theRunoperation. The following colorsaround the Status button indicate theCheck Dataresults:

A red border indicates that errors were found.

A yellowborder indicates that warnings were generated.

A blackborder indicates that no errors were found whenCheck Datawas last performed.

In all cases, the status can be viewed by selecting theStatus button.

To see the current global status messages for your simulation:

➤ Choose Status from the Run palette. TheFlowsheet Statuswindow appears. TheCheck Dataresults appear in a scrollable window.

Figure 10-2: Flowsheet Status

If errors were detected, you must correct your simulation data.

➤ Choose Close to exit theFlowsheet Statuswindow.

➤ Correct your simulation errors.

If no errors were detected, run the simulation.


Understanding the Unit Color Coding CuesAs the simulation progresses, you will observe that the individual unitswill change color. Refer to the following for the default color codes.

Unit Color Coding

Color Significance

Yellow Unit operation at initial condition.

Red Unit operation has not been solved.

Green Unit operation in process of being calculated.

Blue Unit operation has been solved.

Dark Blue Unit operation has been calculated.This color is displayed only when you use the Run button, and a unitoperation was previously calculated.

Purple Breakpoint set directly before or after a unit operation

Using the No Colors Feature

If you do not wish to see the unit icon colors update as the flowsheetsolves, you can get a performance benefit by deselecting theView/ShowRun Colorsoption on the menu bar. This option operates exactly likethe Run button on the Run palette, but unit icon colors are updatedonly when the simulation finishes or stops at a breakpoint.

Running the SimulationWhen you begin executing the simulation, the flowsheet convergencecan be viewed in aMessageswindow by clicking on the Messagesbutton on the Run palette. You can close this window by clicking againon the Messages button or by double-clicking on theMessagewindow’s control-menu box.

Use Run to begin executing the simulation. The program starts from:

● The first unit, if this is the first run;

● The unit at which the calculations were stopped;

● The unit you selected using the Goto option.

The Run option automatically runs Check Data.


To begin executing the simulation:

➤ Choose Run from the Run palette.

When stepping through or stopping simulation execution, you maychoose to examine the status of the simulation.

➤ Select the Status button from the Run palette.

➤ You may continue stepping through the simulation on a unit-by-unit basis by selectingStep .

➤ Alternatively, you may choose to run the simulation without step-ping by selecting Run .

If the run encounters problems, warnings will appear in theFlowsheetStatuswindow. You have the option to close the window and correct thewarnings or continue the run by clicking theRun Simulation button.

Stepping Through Simulation Execution

Use Step to execute the calculations for the current unit (stopping atthe next unit in the calculation sequence). In this manner you can stepthrough the execution of the simulation by stopping at each unitoperation in the calculation sequence.

To step through the execution of the simulation:

➤ Choose Step from the floating Run palette.

If the Messageswindow is open, you can observe that execution ceasesafter completion of the current unit.

Stopping Simulation Execution

Use Stop to interrupt or stop the simulation while it is executing. Theprogram completes its current calculation before stopping.

To stop or interrupt simulation execution:

➤ Choose Stop from the Run palette.

The unit after the calculation stops becomes the current unit, asindicated by its color.


Using Goto

Use Goto to start execution from a selected unit. This can be invokedat program initiation or after execution pauses while stepping orstopping.

To start the execution from a specified unit:

➤ Select a unit on the PFD.

➤ Choose Goto from the Run palette.

The selected unit becomes the current unit. When execution completeson this unit, its Goto status is removed.

Using Breakpoints

You can set a breakpoint on any unit. Breakpoints can be before theunit operation, after it, or both. You can set breakpoints using the cursoror by utilizing theBreakpointswindow. In addition, you can set break-points before and after a loop using theBreakpointswindow.

To set breakpoints using a cursor:

➤ Choose Set Breakpoints from the Run palette to turn on Break-point mode. This automatically brings up theBreakpointswindow.

➤ Select the unit for which you want to set a breakpoint.

➤ Choose Close to exit theBreakpointswindow.

PRO/II turns units selected as breakpoints purple and updates thevalues in theBreakpointswindow.

To delete a breakpoint in Breakpoint mode:

➤ Select the unit. PRO/II will no longer show this unit as purple.

PRO/II updates the values in theBreakpointswindow to show that thereis no longer a breakpoint attached to this unit.

TheBreakpointswindow lists all unit operations in the calculationsequence and identifies the breakpoint type for each unit: (before, after,both). Units without a breakpoint are considered “Off.” Breakpointsare for use during the current session. PRO/II does not save breakpointinformation.

To set breakpoints using theBreakpointswindow:

➤ Choose Set Breakpoints from the Run palette. TheBreakpointswindow appears.


Note: Click on theShow Breakpointsbutton to highlight those units orloops where breakpoints have been previously set.

Figure 10-3: Breakpoints Window

➤ Set the desired breakpoint type by clicking on the check boxes.You can set before, after, or both.

➤ Select a unit from the list.

The breakpoint for the unit is set based on the breakpoint placementyou select.

To close theBreakpointswindow:

➤ Choose Close .

Note: Closing the Breakpoints window does not turn off Breakpoint mode.

To turn off Breakpoint mode:

➤ Choose Set Breakpoints on the Run palette a second time.


Viewing Calculation HistoryUse the Messages button to view the calculation history that has beenproduced so far. This can be used while the simulation is executing, afterthe simulation finally ends, or when the simulation reaches a breakpoint.

To view the calculation history for the simulation thus far:

➤ Choose Messages from the Run palette.

TheMessageswindow appears. This is a multiline data window that iscontinuously updated.

Viewing ResultsUse the View Results button to display results for the selected streamor unit in the default text editor.

To view results for a stream or unit:

➤ Select the desired stream or unit.

➤ Choose View Results from the Run palette, or

➤ Click on theView Resultsicon on the toolbar.

Alternatively, you can view process unit and stream results via theUnitList andStream List(Go To) windows:

➤ Click on the unit or stream icon to open theUnit List or Stream Listwindow.

➤ Highlight the desired unit or stream.

➤ Click on theView Resultsicon.

The PRO/II report generator creates a single ASCII file.

The default text editor will be used to display the standard PRO/IIoutput for the selected stream or unit.

Viewing Results in Stream Property TablesThe stream property tables provide a convenient means to display selectedresults for a group of streams on the PFD. Four predefined report formatsare supplied. These formats may be modified as desired and/or additionalformats may be defined by the user. In addition to the stream propertiesselected for display, the titles and number of decimal places to display foreach stream property may be chosen by the user. A quick check of thematerial balance for the problem may be accomplished by displaying thesource and sink streams for the problem.


Selecting Streams for Property Tables

Stream property tables are set up from the PFD palette by adding astream properties icon to the PFD.

➤ Double-click the stream properties icon on the PFD to display theStream Property Tablewindow.

➤ Choose the method for available stream selection by selecting theappropriate radio button:

Include All Streams: This is the default. All the streams in the flow-sheet are displayed in theAvailable Streamslist box.

Include Flowsheet Source/Sink Streams: Only those streams enteringthe flowsheet as feeds and leaving the flowsheet as products aredisplayed in theAvailable Streamslist box, producing a materialbalance check for the flowsheet.

The streams in theDisplayed Streamslist box may be sorted using theUp , Down , Top and Bottom buttons.

Customizing the Stream Property Tables

The appearance of a stream property table may be customized withoptions provided on theStream Property Tablewindow. The propertylist (format) to use for the display may be selected in theProperty Listto be Usedlist box. Note that in addition to the property lists suppliedby PRO/II, the user may also prepare special property lists forselection. SeeDefining Stream Property Listsbelow for information.

Contiguous strings of components may be grouped into a singlecomponent group for printout. For example, a C6 plus componentgroup might be used to group all components from NC6 and heavier.Any number of component groups may be set up. To specify acomponent group click theDefine Component Groups… button on theStream Property Tablewindow to access theGroup Componentswindow. This window may be used to define and name componentgroups, as well as to edit existing component groups.

The appearance of the steam property table itself may be altered by theuser in theStream Property Tablewindow. Options include multiple rowsper table, displaying the row grid lines, and setting the widths for theborders, lines, and property cell characters.


Defining Stream Property Lists (Formats)

Stream property lists are defined and edited via the Define PropertyList window. This window is accessed by choosingOptions/StreamProperty Listsfrom the menu bar.

PRO/II provides four default lists that may be edited if desired:

Short Property List: Temperature, Pressure, Molar flowrate, Phase.

Material Balance List: Temperature, Pressure, Molar flowrate, Phase,Molar based composition.

Stream Summary: Phase, Molar flowrate, Standard liquid flowrate,Temperature, Pressure, Molecular weight, Enthalpy, Specific enthalpy,Mole fraction liquid, Reduced temperature, Reduced pressure, Acentricfactor, UOP K-value, Standard liquid density, Vapor and liquid molarflowrate, Vapor and liquid mass flowrate, Vapor and liquid volumetricflowrate, Vapor and liquid molecular weight, Vapor and liquid specificenthalpy, Vapor and liquid CP, Vapor and liquid density, Vapor andliquid viscosity, Vapor and liquid thermal conductivity, Liquid surfacetension.

Comp. Molar Rates: Molar component and total flowrates, Temperature,Pressure, Enthalpy, Molecular weight, Mole fraction vapor and liquid.

To edit an existing property list:

➤ Use the drop-down list box to select the property list name.

To create a new property list:

➤ Click the New button to access theNew Listwindow and enter aname for the new list in this window. This window also allows youto select an existing list from a drop-down list box to be copied tocreate the new list.

To add a property to a property list:

➤ Select the property in theSelect Propertiesdrop-down list box ontheDefine Property Listwindow and click the button to transferthe property to theProperty Description Formatlist box.

The property that was selected is expanded in this window, with theaddition of a description and a format which may be edited in the dataentry fields provided. The description for the property may be changedfrom the default value and the number of decimal places for printoutmay also be changed if desired.

When editing an existing property list, properties may be selected in theProperty Description Formatlist box and edited, deleted, or rearrangedas desired.


In addition to such properties as temperature, pressure, enthalpy, etc.,property items such as “double line,” “line,” and “text” may be incor-porated in a property list to add blank lines and special headings.

Running a Case StudyCase Studyis an executive level feature that allows you to performstudies on a base case solution by altering parameters selectively andrerunning the simulation.

➤ Access theCase Studymain data entry window by selectingInput/Casestudy Data… from the menu bar.

Figure 10-4: Case Study Main Data Entry Window

➤ Enable the window by checking theDefine Case Studybox.

In this window you can specify the changes you want to make to yourinput Parametersand to define theResultsyou want to examine. Youmay define as many parameters and results as you want.

Parameters: The table of parameters initially has one row. You mayinsert or remove as many rows as you wish.

Parameter Identifier: The parameter identifier defines the way you wantthe output data to be presented after theCase Studyhas been executed.A default identifier (here “PARAM1”) is supplied. To change theparameter identifier, click on the data field and enter a new name.

Parameter: You must identify a parameter to change. Click onParameterto open theParameterwindow. Select the parameter that youwant to change. When you close this window, the parameter you havespecified appears in place of the original text.


Start Value: Click on Base Case Valueto open theParameter StartValuewindow where you define the starting value for the parameter.The starting value defaults to the value of the parameter in the basecase. When you close this window, the starting value will be displayed.

Start Cycle: The start cycle is the cycle after which the incrementalchanges are implemented. Cycles before the start cycle use the value inthe base case. If necessary, enter a new start cycle number. By default,the starting cycle is one (1).

End Cycle: Cycles after the end cycle use the value in the end cycle. Ifnecessary, enter a new end cycle number. The end cycle defaults to thevalue of the start cycle.

Step Value: Next, define the value of the incremental step change percycle. The new step value will be displayed.

Results: The table of results initially has one row. You may insert orremove as many rows as you wish. You may define aResultas oneflowsheet parameter or as a function of two flowsheet parameters or asa function of one flowsheet parameter and a constant. SeeSPEC/VARY/DEFINEin Chapter 9 for details on using and changing mathe-matical operators and composing specifications.

Result Identifier: The result identifier will be used when you define howyou want the output data to be presented after the Case Study has beenexecuted. A default identifier is supplied. To change the result identi-fier, click on it and enter a new identifier.

First Parameter: Click on the first (or only) parameter to open theParameterwindow where you select the parameter that you want as aResult or as the first element of the function you are defining.

Second (Reference) Parameter: Click on second parameter to open theParameterwindow where you select the parameter (or constant) thatyou want as the second element of the function you are defining.

Execution Options: Select from theExecute:list to execute the base caseonly or the base case and the case study. If you do not want to executeall the cycles of the case study, selectBase CaseandSpecified Cyclesand specify a beginning and ending cycle.


Viewing Case Study ResultsSelectOutput/Case Study/Plots…or Output/Case Study/Table…fromthe menu bar to specify the format of your Case Study results. Afterentering a required name and optional title for the plot or table, click onthe Data… button to open a window where you may specify theparameters and results you wish to have plotted or tabulated, enterlabels for the axes of the plot or rows and columns of the table, etc.

Running Files in Batch ModeYou can execute one or more PRO/II ASCII keyword input files orflowsheet simulation files inBatch Modefrom within PRO/II.

The keyword input file may be one that was created using a text editoror word processor, or one that was previously created using theKeyword File Exportcapability. You can also execute flowsheet simu-lations that were created using PRO/II from the GUI, or were createdby importing a PRO/II keyword input file.

The batch execution of keyword input files or simulation files generatesthe standard PRO/II ASCII output file for each of the selected files.

While executing simulation problems in batch mode, you can continueto work with other Windows applications. You can terminate thecurrently executing problem or the batch execution mode completely bypushing the Terminate Current Problem or Terminate Batch Runbuttons, respectively.

To select a PRO/II keyword input file, simulation file (or group offiles), or a previously stored execution list file:

➤ Close the currently open simulation.

➤ ChooseFile/Run Batchfrom the menu bar. PRO/II displays theRun Batch - Input and/or Simulation Files Selectionwindow.


Figure 10-5: Run Batch - Input and/or Simulation Files Selection

Initially there are no keyword input (*.INP) or simulation files (*.PR1)displayed in theFile Sequencewindow. There are two methods ofadding keyword input or simulation files to the file sequence list:

➤ Select the files explicitly using theAdd Files… button, or

➤ Load a previously saved list of files using theLoad List… button.

To select the desired keyword input or simulation files:

➤ Click he Add Files… button.

PRO/II displays a list of available existing keyword input files. Thedefault file type is keyword files (*.INP). You can change the file typeto simulation files (*.PR1, *.PRZ) using theFiles of typedrop-downlist-box.


Figure 10-6: Run Batch - File Select

➤ Type or select the name of the file that you want to execute. Youcan select multiple files within a given directory. Only the key-word input files highlighted in the currently selected directory willbe added to the list of files to execute when you exit this window.

➤ Click the OK button to validate your selection and return to theRun Batch - Input and/or Simulation Files Selectionwindow.

To load an existing list of keyword input and/or simulation files:

➤ Click on the Load List… button.

PRO/II displays a list of available existing execution list files. Thedefault file type isRun Batch List(*.LST). These files contain thecomplete path and name of keyword input and simulation files in theexecution order previously specified by the user. An example of thetypical contents of an execution list file is given below:

C:\SIMSCI\PROII_W\USER\CASE1.INPC:\SIMSCI\PROII_W\USER\CASE2.INPC:\SIMSCI\PROII_W\USER\CASE3.INP

Execution list files may include comment lines (beginning with asemicolon ;), and include list file directives given by #include followedby the .LST file name. An example is given below:

; This is a commentC:\SIMSCI\PROII_W\USER\CASE1.INPC:\SIMSCI\PROII_W\USER\CASE2.INP; The following list file to be loaded; contains flash problems#include flash.LST


Note: The #include directives may be nested, e.g., in the exampleabove, flash.LST itself could contain the directives #include dewpt.LSTand #include bubpt.LST.

Figure 10-7: Run Batch - Load File List

➤ Type or select the name of the execution list file that you want toload. You can select multiple list files within a given directory.Only the list files highlighted in the currently selected directorywill be used to create the list of keyword input and simulation filesto be executed.

➤ Click the OK button to validate the selection and exit the win-dow.

When you return to theRun Batch - Input and/or Simulation FilesSelectionwindow, the contents of the previously selected execution listfile(s) will have been expanded and are now displayed in theFileSequencelist box. Selected files will be added to the bottom of the listof previously selected files displayed in theFile Sequencelist box.

Revising the File Execution Sequence Order

You can revise the order in which the selected files are to be executedusing the Remove , Move Up , Move Down , Move Top and

Move Bottom buttons.

Creating an Execution File List

You can store a list of keyword input or simulation files as anExecutionFile List that can be retrieved and executed at a later date.

➤ Click on the Select from Lists… button.


PRO/II displays theRun Batch - Save File List Aswindow containingthe execution file list options.

Figure 10-8: Run Batch - Save File List As

➤ Enter a name for theExecution List File.

➤ Click OK to store the list as a *.LST file in ASCII format.

Executing the Batch List

When you return to theRun Batch - Input and/or Simulation FilesSelectionwindow, you can begin the execution of the specified file list. Tostart the batch mode execution of the list:

➤ Click on the OK button.

The specified list will be executed in the order shown in theFile Sequencebox. When the execution is complete, a message will be displayed to notifyyou that the batch mode execution has been completed.

Terminating Execution of a Batch List

You have the choice of terminating the currently executing simulationproblem, or terminating the batch mode execution completely.

To terminate batch mode execution of the selected keyword files:

➤ Click on the Terminate Current Problem button to terminate thecurrently executing problem.

The problem execution will stop after the current unit calculations arecomplete.

Note: You can terminate an executing problem only during calculation.

To terminate batch mode execution completely:

➤ Click the Terminate Batch Run button to end the execution.


Viewing Output ResultsResults of Batch Execution of Keyword Input (*.INP) Files: By default, theprogram deletes the simulation files that remain after batch modeexecution of specified keyword input files (*.INP). The standard PRO/IIASCII output report will be located in the corresponding .OUT file(s).

Results of Batch Execution of Simulation (*.PR1, *.PRZ) Files: By default, theprogram will not delete the simulation files that remain after the batchmode execution of specified simulation files (*.PR1, *.PRZ), or theASCII format standard output report located in the corresponding .OUTfile. You can open the resulting simulation file(s) with theFile/Opencommand, and then proceed to generate reports or modify the simula-tion flowsheet as desired in PRO/II.

Whatever type of file (keyword input or simulation) was executed inbatch mode, you can always view and edit the corresponding standardASCII output files with any ASCII-capable text editor or wordprocessor.


Chapter 11Printing and Plotting

This chapter describes how to generate, view and print reports, andgenerate and print plots. Printer setup is also described.

Defining Output FormatPRO/II provides a variety of report options for streams, unit operationsand dimensional units. You can change the output format of a report forany solved simulation without re-executing the simulation.

To define the output format:➤ ChooseOutput/Report Formatfrom the menu bar. TheReport For-

matmenu appears with options forUnits of Measure, Miscellane-ous Data, Stream Properties, andUnit Operations.

Figure 11-1: Report Format Menu

Setting Miscellaneous Data Report OptionsYou can set the report dimensions, identify the data you want to includeand set the product stream scaling using theMiscellaneous Dataoption.

To set miscellaneous data options:➤ Choose theOption/Report Format/Miscellaneous Datafrom the

menu bar. TheMiscellaneous Report Optionswindow appears.

PRO/II User's Guide Chapter 11 Printing and Plotting11-1

Figure 11-2: Miscellaneous Report Options

Setting Product Stream ScalingTo change the scale stream flowrate:➤ Choose theProduct Stream Scaling… button from theMiscellane-

ous Report Optionswindow. TheReport Options - Product StreamScalingwindow appears.

➤ Select theScale Stream Flowratecheckbox.

➤ Specify the stream to be scaled, the components to be scaled, andthe scaled flowrate.

Figure 11-3: Scale Stream Flowrate

➤ Click OK twice to commit the changes and return to the PFD.

Chapter 11 Printing and Plotting PRO/II User's Guide11-2

Setting Stream Properties Report OptionsTo set the stream properties report options:➤ Choose theOutput/Report Format/Stream Propertiesmenu item.

TheStream Property Report Optionswindow appears (Figure11-4).

➤ Select the desired flowrate, fractions, or percent values for theStandard Component Flowrate/Composition Report.

➤ Click OK to commit the entries and return to the PFD.

Figure 11-4: Stream Property Report Options

Setting Units of Measure Report OptionsIn addition to the global, problem and unit level default units ofmeasure you set for input data, you can also setProblem Units ofMeasurefor output reports. You can change the output values for all thefields by applying a different units of measure set or you can make indi-vidual value adjustments.

To set units of measure for output reports:➤ Choose theUnits of Measuremenu item from theReport Format

menu. TheDefault Units of Measure for Problem Output Reportwindow appears.


Figure 11-5: Default Units of Measure for Problem Output Report

➤ Click Initialize from UOM Library… to extract default values fromanother set or replace the default values as necessary.

➤ Optionally, click Standard Vapor Conditions… to change thevapor condition settings for this problem. TheProblem StandardVapor Conditionwindow appears.

Figure 11-6: Problem Standard Vapor Conditions

➤ Specify the desired standard vapor conditions.

➤ Click OK in the child windows to return to the PFD.

Setting Unit Operations Report OptionsYou can set specific print options for each type of unit operation.

To set the unit operations report options:➤ Choose theOutput/Report Format/Unit Operationsmenu item. The

Unit Operation Output Report Optionswindow appears.


Figure 11-7: Unit Operations Output Report Options

➤ Select the desired unit operation.

➤ Choose Print Options… . TheColumn Print Optionswindowappears.

Figure 11-8: Column Print Options

➤ Select the items you want to include in a Column Report.

➤ Optionally, click Plot Column Results… to set options for a plot.TheColumn Plot Optionswindow appears.


Figure 11-9: Column Plot Options

➤ Click OK in the child windows, thenClose to commit theentries and return to the PFD.

Generating a ReportYou can generate a report to a file. Use theDefine Formatoption todefine the format of the report.

To generate a report from an executed simulation:➤ Click on theGenerate Reportsicon on the toolbar, or choose

Output/Generate Reportsfrom the menu bar.

As PRO/II generates the report, a window appears, displaying the statusof the report as it runs. Once the report has been generated, the defaulteditor window appears displaying the contents of the report.

PRO/II appends an .OUT extension to the current simulation name andsaves the file in the USER directory.

Viewing a ReportTo view a previously generated report of the current simulation:➤ ChooseOutput/View Reportfrom the menu bar.

To view a previously generated report for any simulation:

➤ ChooseFile/Openfrom the menu bar.

➤ SelectReport Filesin theList Files of Typelist box and choose thedesired file.


Printing a ReportTo print the report:➤ Print from your text editor while viewing the report, or

➤ ChooseFile/Print from the menu bar.

➤ SelectReportin thePrint drop-down list box in thePrint window.

➤ Click OK .

PlottingPRO/II generates and displays a variety of plots for input data andtabulated results. The following plots can be generated:

● Input Data

● Assay stream analysis

● Output Results

● Distillation column profiles (temperature, flowrates,composition, and separation factor)

● Zones analysis for simple and rigorous heat exchangers

● Phase envelopes

● Heating/Cooling curves

Plots can be displayed using PRO/II’s Plot Viewer or Microsoft Excel.The sectionSetting Up the Plot Driverlater in this chapter describeshow to select and configure the plot driver.

Generating a PlotTo generate an assay stream analysis plot, select theView Curve...button on theStream Assay Definitionwindow. Three curves will begenerated:

● The actual user input distillation data

● The regressed TBP curve

● The component cuts generated.

To generate one of the output results that PRO/II supports:➤ ChooseOutput/Generate Plotfrom the menu bar.PRO/II displays

theGenerate Plotwindow as shown in Figure 11-10.


Figure 11-10: Generate Plot Window

By default, theUnits for Selectionlist box displays all the unit opera-tions in your flowsheet for which plots are available. If you check theSelected Unitsoption, only those units you previously selected on thePFD for which plots are available will be shown.

When you select a unit operation in theUnits for Selectionlist box, theAvailable Plotslist box displays all plots available for that unit. Youmay select a plot then click on thePlot… button to display the plot. Ifthe plot requires additional options to be chosen, thePlot… buttonwill change to an Options… button. Currently, additional data isrequired only for Distillation Column Plots.

Plotting a ColumnTo obtain a plot of vapor and liquid compositions:➤ ChooseVapor and Liquid Compositions, then chooseOptions…

to open the Column Vapor and Liquid Composition Plot window.

Figure 11-11: Column Vapor and Liquid Composition Plot

➤ Enter the additional data required.

➤ Click the Plot… button.


Setting Up the Plot DriverPRO/II can display plots using its internal Plot Viewer or MicrosoftExcel (through version 7).

The PRO/II Plot Viewer is a built-in utility that also prints plots.

Microsoft Excel provides a complete set of formatting features. WithExcel you can change plot colors, axis titles, and other attributes tocreate a presentation-quality graph.

To select and configure the plot driver:➤ ChooseOptions/Plot Setupon the menu bar to open thePlot Setup

window.

Figure 11-12: Plot Setup Window

PRO/II’s installation procedure will set up the options in this window. Selectthe desired plot driver using the list box. If you need to configure thecurrently selected plot driver, press theSetup button to display theSetupPlot Driver window. You cannot configure the PRO/II Plot Viewer (option“SIMSCI”).


Figure 11-13: Setup Plot Driver Window

The configuration options are:

Driver File: The complete path and filename of the dynamic link library(DLL) for the plot driver.

Driver Function: The function name to invoke the driver.

Command Line: The full command line to invoke the plotting application.

Options: Additional driver-specific options.

The Plot ViewerPRO/II’s Plot Viewer utility lets you view a plot, print it, copy it to theclipboard, and export its data to a file. Modifications of plot attributesare not supported. If you want access to comprehensive editing andformatting features for your plot, choose the Excel plot driver.

Saving, Sending, etc.To save a plot:➤ ChooseFile/Save Asfrom thePlot window menu.

➤ Enter the desired plot file name and clickOK .

You can send a plot from thePlot window to your plotter.

To send a plot to the plotter:➤ ChooseFile/Print from thePlot window menu.

To export a plot to an ASCII file:➤ ChooseFile/Export from thePlot window menu.

➤ Select the file type (tab- or comma-delimited) and clickOK .

To copy the plot image to the clipboard:➤ ChooseEdit/Copyfrom thePlot window menu.


Setting Up the PrinterTo set up the printer:➤ ChooseFile/Print Setupfrom the menu bar.

➤ Select a printer.

➤ Select paper orientation and size and clickOK .

Printing a Flowsheet LayoutTo print a flowsheet diagram:➤ ChooseFile/Print from the menu bar.

➤ Select the range of pages and clickOK .


Chapter 12Customizing the PFD Workplace

This chapter surveys the customization of PFD appearance. You cancontrol unit and stream appearance, modify the stream property tables,and set the font style used on your PFD.

Changing Unit StyleYou can specify a different icon, name, or label starting number for anyunit operation. These changes affect all unit operations that you subse-quently place on the PFD.

Changing the Unit Icon GloballyTo change the style of a unit globally:➤ ChooseOptions/Drawing Defaults/Unit Display…from the menu

bar. TheUnit Stylewindow appears.

Figure 12-1: Unit Style Window for Classes of Units

➤ Select the type of unit operation you want to change.

➤ Enter your changes for the label format and starting number.

The text portion to the left of the “%” sign is the label displayed withthe unit number. The label may not contain spaces or underscores. Theintegers following “d” are appended to the automatically applied

PRO/II User's Guide Chapter 12 Customizing the PFD Workplace12-1

sequential unit numbers. You may also choose the starting number forthe particular unit. For example, if the Auto Label Format for theFlashunit operation were “FLASHUNIT%d05,” subsequentFlashesplacedon the PFD would be labeled “FLASHUNIT105,” “FLASHUNIT205,”“FLASHUNIT305,” and so forth.

You can also modify the type face and type size used in the stream labelas discussed below under the topicChanging the Default Font.

Changing the Unit Icon for a Single UnitYou can specify a different display icon for any unit operation currentlyshown in your flowsheet. Some unit operations can be represented byseveral different icons. This choice is particularly useful when differentvariants of the same unit operation are being modeled.

Note: Any icon available can be assigned to a User-Added Subroutine.

To change the style of a single unit:➤ Right-click on the icon of the unit you wish to modify. The unit

menu appears.

Figure 12-2: Unit Menu

➤ SelectDisplay...from this menu (or selectEdit/Display Style…from the menu bar) to open theUnit Stylewindow for the selectedunit type as shown in Figure 12-3.

Chapter 12 Customizing the PFD Workplace PRO/II User's Guide12-2

Figure 12-3: Display Style Window

➤ Select an alternative icon from the palette at the top of the window.

➤ Choose OK to confirm the change.

You can also change the type face, type size and color of the unit labelby choosing Select… to access a standard font editing window.

Changing the Label for a Particular UnitPRO/II automatically labels each unit you place it on the PFD. You canchange the label for each unit without altering the numbering sequence.

To change a unit label:➤ Double-click on the unit on the PFD.

➤ Type over the existing “Unit” label in the data entry window.

➤ Commit the change by pressingOK .

Changing Stream StyleYou can modify stream appearance by changing:

● The height and width of the arrows

● The fill of the arrows

● The segments on which the arrows appear

● The label format

● The starting number

● The stream label location

● The stream label border

● The label type (name or list of properties)

● The contents of the property list (material balance, gas report,comparative molars rates, etc.).


To change the style of a stream:➤ ChooseOptions/Drawing Defaults/Stream Display…from the

menu bar to open theStream Stylewindow.

Figure 12-4: Stream Style Window

By default, stream labels have rectangular borders and appear on thestream line. (Optionally, you may select (1) diamond-shaped or circularlabel borders, or, alternatively, no label border at all, and (2) theposition of the label relative to the stream.) Process stream arrows arenot filled and appear only on the horizontal segments of an orthogonalprocess stream. You can change the appearance of the arrows andwhere the arrows appear on the process stream.

Figure 12-5: Default Stream Style


Figure 12-6: Modified Stream Style

Changing the Label for a Particular StreamPRO/II automatically labels each stream as it is placed on the PFD. Youcan change the number or label for just one stream without altering theongoing numbering sequence.

To change a stream label:➤ Double-click on the stream to open theStream Datawindow. Al-

ternatively, right-click on the stream and chooseData Entry….

Figure 12-7: Stream Data Entry Window

➤ Enter the new stream name in theStreamentry field.


Displaying Stream Properties on Stream LabelsPRO/II allows you to display various stream properties on labelsattached to the streams on the PFD. Display options include:

● Selecting a global default property list for all stream labels inthe flowsheet

● Choosing from a group of predefined property lists

● Creating a custom stream label property list

● Positioning stream property labels anywhere on or beside thestreams on the PFD

● Choosing the type of border for any label

● Choosing a different font for any label

To Select a Global Default Steam Property:➤ ChooseOptions/Drawing Defaults/Stream Display…from the

menu bar to open theStream Stylewindow.

➤ From theStream Label Typedrop-down list choose thePropertiesoption.

➤ Choose one of the predefined property lists and clickOK to com-mit your choice.

The property list that you have selected will appear on all streamssubsequently drawn on the PFD.

Creating a Customized Stream Property List

PRO/II allows you to create customized property lists for use in StreamProperty Tables. You can use the same property list in more than onesimulation. The default Stream Property Table is outlined by a single-lined rectangular box. You may arrange the properties in any desiredorder, and you may separate entries by single or double horizontal linesto improve the legibility of the list.

To select a property list:➤ ChooseOptions/Stream Property Listsfrom the menu bar to dis-

play theDefine Property Listwindow (Figure 12-8).


Figure 12-8: Define Property List Window

➤ Select a list from theProperty Listbox (Figure 12-9).

Figure 12-9: A Typical Property List

➤ You can add or delete properties, modify the property descriptionand change the numerical format.

To create a property list:➤ Choose New… from theDefine Property Listwindow. TheNew

List window appears.


Figure 12-10: New List Window

➤ Enter a name for the new list,or

➤ Select the list from which you want to copy an existing propertylist.

➤ Choose OK to commit the entries.

To add one or more properties to a list:➤ Select the desired properties. (The usual Windowsclick, shift-click

andcontrol-clickselection options are supported.)

➤ Choose Add-> .

The selected properties will be added to the bottom of the property list.

To change the order of the properties in a list:➤ Select the properties you want to move.

➤ Use the Up , Down , Top , Bottom buttons to move the se-lected properties.

To change the description or the format of a property:➤ Select the property you want to change.

➤ Enter the new description and format in the entry fields under theproperty list.

➤ Commit the changes using theReplace button.

To delete a property from a list:➤ Select the properties you want to delete.

➤ Choose Remove .

To clear (delete) all properties from a list:➤ Choose Clear .

To demarcate sections of a list:➤ Insert single or double horizontal lines where desired.


Positioning Stream Property Labels on the PFDYou may place stream labels on, above, below or beside the streams onthe PFD. The labels may appear with or without stems connecting themto the streams.

To position stream labels:➤ ChooseOptions/Drawing Defaults/Stream Display…from the

menu bar.

➤ Select the desired position from theStream Label Locationdrop-down list.

➤ Click OK to commit your selection.

Alternatively, you may drag a stream label to any of these positionsfrom the PFD itself.

While in theStream Styleswindow, you may also choose a text font anda border style for the labels from the corresponding drop-down lists.

Modifying Drawing PreferencesDrawing preferences include settings for snap and move tolerances,zoom and pan increments, the PFD palette icon, icon fill, unit snapping,and delete confirmation.

To modify drawing preferences:➤ ChooseOptions/Drawing Defaults/General…from the menu bar.

TheGeneral Drawing Defaultswindow appears with current settings.The settings can be changed as desired.

Specifying a Default EditorYou can specify a default editor (such as Brief, Edit or Notepad) for usewith PRO/II to display output reports and keyword input files. Usingthe editor, you can save any displayed text to a file or printer. Thedefault editor is the Programmer’s File Editor (pfe.exe).

To specify a default editor:➤ ChooseOptions/Editorfrom the menu bar to open theSet Text

Editor window.

➤ Enter the full path name to the editor executable program file.


Figure 12-11: Set Text Editor

Changing the Default FontThe Default Font option enables you to set the default font, font styleand size used in PRO/II’s main and data entry windows. This option isuseful if the default font size for your system is too large for PRO/II’sdata entry windows.

Note that you cannot change the fonts for the title, menu, and status bartext. Also, changing the font size will not change the size of PRO/II’swindows.

To specify the default font:➤ ChooseOptions/Fontfrom the menu bar to display theFont speci-

fication window.

➤ Choose the desired font, font style, and size.

Figure 12-12: Font Window


IndexA

Align text 5-6

All objects

selecting 5-2

Assay

cutpoints andcharacterization window 7-5

data, selecting 7-2,7-5

Assay data 1-10

AutoCAD

exporting to a .DXF file 3-13

BBorder handles 1-4

using 1-5

Bounding box

changing its size 6-4

moving 6-4

Breakpoint mode

turning off 10-7

Breakpoints 10-2

deleting 10-6

setting using a cursor 10-6

using 10-6

Breakpoints window 10-7

closing 10-7

Broyden 9-73

BVLE

See Unit operations

CCalculation history

viewing 10-8

Calculation sequence 1-10,7-2

Calculator

intrinsic functions 9-8,9-9

See Unit operations

Calculator procedure

FORTRAN GOTO/IF/DO 9-11,9-12

FORTRAN STOP/RETURN 9-14

stream property storage 9-10

Cancel

connection 4-16

selection 5-3

unit placement 4-13

Change

bounding box size 6-4

connection 4-16

delete confirmation 4-10

flowsheet layout 4-18

object size 5-3

product stream scaling 11-2

single stream label 12-5

single unit label 12-3

standard vapor condition 11-4

unit icon 12-2

unit size 5-3

unit style 12-1

unit styles globally 12-1

window position 1-5

PRO/II User's Guide IndexI-11

Change PFD image size

using Pan Viewwindow bounding box 6-4

Change PRO/II window size 1-5

Clipboard

copying a stream property table 3-13

copying stream data 8-31

copying the PFD 3-12

Close

breakpoints 10-7

Close simulation 3-4

Color coding cues 1-6

Column plot options window 11-6

Column print options window 11-5

Component properties 1-10,7-2

Component selection 1-10,7-2,7-3

Component selection window 7-3

Compressor

See Unit operations

Connection

canceling 4-16

changing 4-16

drawing 4-16

Control menu 1-4

Controller

Unit operations 1-1

Converting

flowsheet to PRO/II keyword file 3-12

Copy

simulation 3-5

Copy file selector 3-5

Create units of measure set window 4-6

Customizing Data Entry windows

See User-added Unit Operations

DData entry window buttons 1-10

Default editor

specifying 12-9

Default fonts

setting 12-10

Default Levels 4-1

Default unit specification tolerances window4-11

Define

output report format 11-1

scope of simulation 7-1

Define format submenu 11-1

Define Property List window 12-7

Delete

simulation 3-4

unit 4-13

Delete confirmation

turning off 4-10

Deleting

breakpoints 10-6

Depressuring unit

See Unit operations

Deselecting objects 5-3

Display

Pan View window 6-4

Distillation column

See Unit operations

Draw

connections 4-16

freehand objects 4-20

Index PRO/II User's GuideI-12

incoming streams 4-15

outgoing streams 4-16

polylines 4-21

squares 4-22

streams 4-15,4-16

Draw text window 4-20

Drawing freehand objects 4-20

Drawing preferences

modifying 12-9

Dsipalying the complete flowsheet

See Zoom full

EEdit

text 5-6

Editor

specifying default 12-9

Electrolyte version 9-157

column algorithm (ELDIST) 9-158

thermodynamic models 9-157

Enter

flowsheet tolerances 4-11

text 4-20

Existing simulation files

opening 3-2

Expander

See Unit operations

Exporting

See AutoCAD

flowsheet 3-12

PRO/II keyword files 3-10

stream property table data 3-12

FFill from structure 8-7

Flash

See Unit operations

Flip

selected objects 5-6

unit icon 5-6

Flowsheet

exporting 3-12

redrawing 6-3

Flowsheet layout

changing its shape 4-18

printing 11-11

Flowsheet optimizer

See Unit operations

Flowsheet tolerances

entering 4-11

Fonts

setting default 12-10

Freehand objects

drawing 4-20

GGeneral Drawing Defaults window 4-10

Generate

plot 11-7

reports 11-6

Gibbs reactor

See Unit operations

Global defaults 4-1

problem description 4-1

thermodynamic systems 4-9

units of measure sets 4-3


Global defaults thermodynamic systemwindow 4-9

Global units of measure sets window 4-3

gnuplot

See Plot

Go To buttons 1-11

Go To stream 4-18

Go To Stream 1-11

Go To unit 4-18

Go To Unit 1-11

Goto 10-2

setting current unit for execution 10-6

using Run palette 10-6

Grid snapping 4-13

turning off 4-13

Group of Objects

selecting 5-2

HHeating/cooling curves

See Unit operations

Help for an item

See What Is?

Hide

Pan View window 6-4

Horizontal Scroll Bar 1-4

IIcon

flipping 5-6

rotating 5-6

Icon style window 12-1

Importing

PRO/II keyword file 3-7

unsupported features 3-8

Incoming streams

drawing 4-15

LLarge pan 6-5

Liquid-liquid extraction column

See Unit operations

LNG heat exchanger

See Unit operations

Locating a unit or stream on the PFD 4-18

MMaintain stream property lists 12-6

Maximize/Restore buttons 1-4

Menu bar 1-4

Menus

using 1-6

Microsoft Excel

See Plot

Minimize button 1-4

Minimize/Maximize buttons

using 1-5

Miscellaneous data

setting report options 11-1

Miscellaneous report options window 11-2

Mixer

See Unit operations

Move


streams 4-17

Move tolerance

setting 5-5

MS Excel

See Spreadsheets


MS Word

See Word processors

Multiple objects

selecting 5-1

Multiple unit icons

placing 4-13

NNew list window 12-8

New simulation

opening 3-1

OObject size

changing 5-3

Objects

deselecting 5-3

drawing freehand 4-20

flipping 5-6

moving 5-5

rearranging 5-5

resizing 5-3

rotating 5-5

selecting 5-1

selecting all 5-2

selecting group 5-2

Open

existing simulation 3-2

new simulation 3-1

Open simulation window 3-2

Operating modes 1-9

Orthogonal polylines 4-21

Outgoing streams

drawing 4-16

Output format

defining 11-1

PPalettes

PFD 4-12

Run 1-9

Pan

large 6-5

Up/Down/Left/Right 6-5

Pan View window 6-4

bounding box 6-4

displaying and hiding 6-4

panning with 6-4

Panning 6-3

using menu options 6-5

using the Pan View window 6-4

Panning sensitivity

setting 6-5

PFD 1-4,1-13,3-1

scrolling 6-1

Place

multiple unit icons 4-13

selected unit 4-12

Plot

generating 11-7

Microsoft Excel 11-9

output results 11-7

viewer 11-9

Polylines

drawing 4-21

Ports

color changes 4-16

connecting 4-16

Print


flowsheet layout 11-11

Printer setup 11-11

PRO/II icon 1-1

PRO/II keyword file

importing 3-7

PRO/II main window

components 1-4

manipulate 1-5

PRO/II menus 1-6

Problem

defining scope 7-1

Problem default units of measure

sets 4-4

window 4-4

Problem defaults units of measure 4-1

Problem description 1-10,7-2

setting global defaults 4-1

Problem standard vaporconditions window 11-4

Problem units of measureset output report 11-4

Procedure data

predefined variables 9-107

Product stream scaling

changing 11-2

RReaction data 1-10,7-2

See Unit operations

Rearrange

objects 5-5

Recycle options 1-10,7-2

Redraw 1-12

simulation 6-3

Reference Manual

See Online Reference Manual

Relabel

specific unit 4-14

stream 4-17

Report

generating 11-6

viewing 11-6

Report format

defining 11-1

Report options

miscellaneous data 11-1

unit operations 11-4

units of measure 11-3

Re-route

streams 4-17

Resize

object 5-3

Resize PRO/II window 1-5

Restore

unit icon size 5-5

Results

viewing 10-8

Rotate


unit icon 5-6

Run 10-2

displaying palette 1-9

simulation 10-4

Run palette

using 10-1

Run-only mode

See Also Unsupported Features


SSave

current simulation 3-2

simulation to another name 3-3

Save As dialog box 3-3

Scale stream flowrate window 11-2

Scroll bar

Horizontal 1-4

Vertical 1-4

Scrolling

PRO/II main window 6-1

Scrolling increments

setting 6-1

Select

all objects 5-2

components 7-3

group of objects 5-2

multiple objects 5-1

objects 5-1

thermodynamic methods 7-4

unit from palette 4-12

Selected objects

moving 5-5

Selection

undoing 5-3

Set

breakpoints 10-6

default font 12-10

move tolerance 5-5

panning sensitivity 6-5

scrolling increments 6-1

zoom increment 6-2

Set report options

miscellaneous data 11-1

unit operations 11-4

units of measure 11-3

Set text editor window 12-10

Setup printer 11-11

SIMSCI Add-on units 9-160

RESET 9-162

SIMSCI Add-on Units

BLEND 9-161

component property reporter 9-161

polymer CSTR 9-160

Profimatics reactors 9-162

SIMSCI’s plot viewer 11-9

Simulation

closing 3-4

copying 3-5

deleting 3-4

open existing 3-2

opening new 3-1

redrawing 6-3

running 10-4

saving 3-2

saving to another name 3-3

step through execution 10-5

stop execution 10-5

Simulation defaults

units of measure sets 4-4

Simulation preferences

setting 4-1

Simulation scope

defining 7-1

Single stream label

changing 12-5

Snapping 4-13


Specifying

default editor 12-9

Spreadsheets 3-12

Squares

drawing 4-22

Standard Vapor Condition

changing 11-4

Starting PRO/II 1-1

Status

unsupported featues 3-9

Status bar 1-4

Step 10-2

Step through simulation 10-5

Stop 10-2

simulation execution 10-5

Stream

relabeling 4-17

searching for 4-18

Stream calculator

See Unit operations

Stream label

changing 12-5

Stream property list

maintaining 12-6

Stream Property ReportOptions window 11-3

Stream style window 12-4

Streams

drawing 4-16

going to 4-18

moving 4-17

re-route 4-17

selecting multiple 5-1

Streams data entry window 8-23,12-5

Streams Mode 4-15

Streams/Unit Palette 4-12

TText

aligning 5-6

editing 5-6

entering 4-20

Thermodynamic data 1-10,7-2

Thermodynamic data window 7-4

Thermodynamic methods

selecting 7-4

Thermodynamic systems

global defaults 4-9

Title bar 1-4

Tool buttons 1-12

Toolbar 1-4

PFD 1-9

standard toolbar 12-9

Toolbar buttons 1-9

Turn off

breakpoint mode 10-7

delete confirmation 4-10

grid snapping 4-13

UUndo

selection 5-3

unit placement 4-13

Unit

deleting 4-13

going to 4-18

relabeling 4-14

searching for 4-18


Unit Data Entry window 4-14

Unit icon

changing 12-2

Unit label

changing 12-3

Unit operation outputreport options window 11-5

Unit operations

Boiling pot reactor 9-120

BVLE 8-43

Calculator 9-2

Compressor 9-42

Continuous stirred tank reactor 9-120

Controller 9-46

Conversion reactor 9-123

Depressuring unit 9-57

Distillation column 9-19

Equilibrium reactor 9-122

Expander 9-63

Flowsheet optimizer 9-70

Gibbs reactor 9-121

Heating/cooling curves 9-89

Mixer 9-93

Multivariable controller 9-94

Phase envelope 9-97

Plug flow reactor 9-120

Pump 9-113

Reaction data 9-114

Reactor 9-118


SPEC/VARY/DEFINE 9-135

Splitter 9-130

User-added unit operations 9-151

Valve 9-163

Unit Operations

Stream calculator 9-132

Unit placement

undoing 4-13

Unit size

changing 5-3

restoring 5-5

Unit specification tolerances

entering 4-11

Unit style

changing 12-1

Units

connecting 4-16

selecting from palette 4-12

selecting multiple 5-1

Units of measure 1-10,7-2


Units of measure library window 4-6

Units of measure sets

global defaults 4-3

problem defaults 4-4

User-added transport methods 8-19

User-added unit operation

creating custom windows 9-153

User-added unit operation window 9-154

User-defined components 2-4

VVertical scroll bar 1-4

View

calculation history 10-8

report 11-6

View buttons 1-12

View convergence 10-2,10-8


View different area in PFD main window

using Pan View windowbounding box 6-4

View results 10-2,10-8

WWelcome window 1-1

What Is? 1-13

Word processors 3-12

ZZoom area 1-12,6-2

Zoom full 1-12,6-2

Zoom increment

setting 6-2

Zooming 6-1


10(user's guide)

Documents