isomerization of light naphtha full and final

ISOMERIZATION OF LIGHT

NAPHTHA

Group No. 1 Batch: 2008-2009

Names Seat no.

MUHIB NASEER MANSURI CH-005

WAHAJ SHAFI CH-006

FARHAN AHMED LARIK CH-058

KHURRAM REHMAN NIZAMI CH-063

Internal Advisor: Sir Fahim Uddin

DEPARTMENT OF CHEMICAL ENGINEERING

NED UNIVERSITY OF ENGINEERING AND

TECHNOLOGY

Dedicated to

Our beloved Parents & Teachers

i

CERTIFICATE

This is to certify that the work in this project report on ISOMERIZATION OF

LIGHT NAPHTHA is entirely written by the following students under the

supervision of Mr. Fahim Uddin. This project is submitted to Department of

Chemical Engineering for the fulfillment of the Bachelor Degree in Chemical

Engineering.

Group No. 1 Batch: 2008-2009

Names Seat no.

MUHIB NASEER MANSOORI CH-005

WAHAJ SHAFI CH-006

FARHAN AHMED LARIK CH-058

KHURRAM REHMAN NIZAMI CH-063

___________ Internal Adviser

___________ ___________ Examiner – 1 Examiner – 2

DEPARTMENT OF CHEMICAL ENGINEERING

NED UNIVERSITY OF ENGINEERING AND

TECHNOLOGY

ii

ABSTRACT

Energy exploration and conservation is one of the most critical challenge faced by

today‘s engineering world. Engineers of various expertises are working all over the

world for developing new modes of power generation and energy conservation. This

surge includes not only to find the new sources of energy but rather more significantly

to enhance the efficiency of already existing resources by adopting more fruitful ways

of power generation and reducing the amount of waste. Conversion of low energy

fuels into high energy fuels is one of the key aspects in this regard.

Petroleum refinery sector is also facing this widespread challenge. De-bottle necking

of various refinery processes are being carried out. For refinery sector, bringing a

maximum amount or refinery product into gasoline pool has been an attractive choice

for years. This has been done by converting various straight run cuts of crude oil into

the gasoline cut which is only about 7% of the feed crude. Several processes including

alkylation, reforming, cracking and isomerization are carried out to enhance the

production of gasoline pool. In Pakistan, the refinery sector is in practice of exporting

Light straight run naphtha (LSR) which is one of the key products, where it is either

used in petrochemical industries or it processed to increase its octane rating thus

making it fit to be used as an automobile fuel.

Isomerization of light straight run naphtha has now been done worldwide to increase

its octane rating. The octane rating of LSR can be enhanced by converting the straight

chain paraffins into branched chains. However the benzene present in LSR is

hazardous for the environment due to its carcinogenicity. This problem can be solved

by saturating this benzene into cyclo-hexane. Consequently a combination of two

processes that is saturation of benzene into cyclo-hexane followed by isomerization of

normal paraffin into iso paraffin under the action of Platinum based on alumina

catalyst is developed.

This report will discuss in detail this process for the LSR produced from Atmospheric

distillation column at Pakistan Refinery Limited. This report will discuss process

history, chemistry of the process, material and energy balances, equipment design,

economics for the process and environmental and safety concerns.

iii

ACKNOWLEDGEMENT

Our first thanks is to Allah The Almighty, the most merciful who blessed us with the

strength to achieve our task and helped us in all ups and downs during the final year

project in particular and in circles of life in general.

This final year project will hopefully serve us as a milestone in signifying the essence

of Chemical Engineering design. This project was rather an expedition characterized

by the team work, as well as by help from various personnel. Henceforth we are in

debt to acknowledge their support and guidance in completion of our project.

First and foremost we would like to acknowledge our project facilitator Engineer

Fahim Uddin who supported us and always drew a helping hand when needed. Most

importantly encouraged us to attempt this project unconventionally and provide us

full autonomy to enhance our talent and abilities.

Secondly, we would like to express our gratitude and acknowledgement to the support

of Engineer Tariq Masood (Senior Engineer Pakistan Refinery Limited) and Engineer

Rashid Hafeez (Process Manager Pakistan Refinery Limited)

Apart from the above mentioned, we would also like to acknowledge the grand

support of Professor Dr. Tufail Ahmed (Dean Chemical and Process Engineering),

Professor Dr. Inayatullah Memon (Chairman DEC) and all the faculty members of

department of Chemical Engineering especially Prof. Dr. Shazia F. Ali, Mr. Asim

Mushtaq, Mr. Adeel-ur-Rehman and our class advisor Mr. Saad Nadeem for his time

by time encouragement.

Authors

iv

CONTENTS

ABSTRACT ii

ACKNOWLEDGEMENT iii

CONTENTS iv

LIST OF FIGURES viii

NOTATIONS x

CHAPTER 1

INTRODUCTION 01-12

1.1 Refinery Products 02

1.2 Automobile Fuels 06

1.3 Octane number 06

1.4 Processing of heavier and lighter hydrocarbons than C7 and C8 07

1.5 What is Isomerization? 10

CHAPTER 2

ISOMERIZATION TECHNIQUES 13-22

2.1 UOP‘S Penex Process 13

2.2 Process Description 19

2.3 Octane Comparison for Different Processes 22

CHAPTER 3

PROCESS DESCRIPTION 23-42

3.1 Simple Process Description 23

3.2 Process Chemistry 24

3.3 Reactions 26

3.4 Process Variables 30

v

3.5 Process Equipment 35

CHAPTER 4

CATALYST SELECTION 43-49

4.1 Catalyst 43

4.2 Types of Catalysts 43

4.3 Dual-Functional Isomerization Catalysts 45

4.4 Alumina Catalyst 46

4.5 Chlorinated-Alumina based Catalysts 48

4.6 Zeolites 48

4.7 Zeolite Characteristics 49

CHAPTER 5

MATERIAL BALANCE 50-65

5.1 Material Balance Equations 50

5.2 Mass Balance on Mixer M 101 53

5.3 Material Balance around Reactors R 101 & R 102 55

5.4 Material Balance around Stabilizer T 101 61

5.5 Material Balance around Scrubber T 102 64

CHAPTER 6

ENERGY BALANCE 66-93

6.1 Energy Balance Equations 66

6.2 Energy Balance Around Reactor R-101 66

6.3 Energy Balance Around Reactor R-102 72

6.4 Energy Balance Around Heat Exchanger E 101 78

6.5 Energy Balance Around Heat Exchanger E 102 85

vi

6.6 Energy Balance Around Stabilizer T 101 92

CHAPTER 7

PLANT DESIGN CALCULATIONS 94-118

7.1 Reactors And its Types 94

7.2 Algorithm for determining reaction mechanism and

rate-limiting step 95

7.3 Designing of Reactor R 101 97

7.4 Designing of Reactor R 102 99

7.5 Designing of Naphtha Feed Pump P 101 101

7.7 Designing of Heat Exchanger E 101 104

7.8 Designing of Stabilizer T-101 107

7.6 Designing of Hydrogen Feed Compressor K 101 113

CHAPTER 8

COST ESTIMATION 119-128

8.1 Cost Estimation 120

8.2 Cost Estimation of our plant 123

8.3 Economics of Plant Location 125

8.4 Plant Location and Site Selection 126

CHAPTER 9

ENVIRONMENT AND SAFETY 129-142

9.1 Definition of a Petroleum Refinery 129

9.2 Background 129

9.3 Processes involved in refining crude oil 130

vii

9.4 Environmental hazards of petroleum refineries 134

9.5 Material Safety Data Sheet 134

CHAPTER 10

INSTRUMENTATION AND CONTROL 143-151

10.1 Components of the Control System 144

10.2 Analysis of Measurement 144

10.3 Controller 145

10.4 Characteristics of Controller 145

10.5 Modes of Control 146

10.6 Alarms and Safety Trips 146

10.7 Control loops 146

10.8 Feed Back Control Loop 147

10.9 Feed Forward Control Loop 147

10.10 Ratio Control 147

10.11 Auctioneering Control Loop 148

10.12 Split Range Loop 148

10.13 Cascade Control Loop 148

10.14 Interlocks 148

10.15 Control of Heat Exchanger 148

REFERENCES 152

LIST OF APPENDICES 154

viii

LIST OF FIGURES

Number Figure Title Page Number

Figure 1.1 Crude Distillation Products 2

Figure 1.2 The isomerization reactions kinetics 11

Figure 1.3 Comparison of operating Conditions of Catalyst 12

Figure 2.1 Hydrocarbon Once-Through Penex Process 15

Figure 2.2 Block flow diagram of ―one through‖ process 17

Figure 2.3 Block flow diagram of process with DIP 18

Figure 2.4 DIP-Penex-DIH 19

Figure 2.5 Penex/Molex Process flow scheme 19

Figure 2.6 BFD of Molex Process 20

Figure 2.7 Octane Comparison for different Processes

{Feed RON = 60 to 70} 22

Figure 3.1 C5 paraffin equilibrium plot 26

Figure 3.2 Equilibrium composition of hexane isomers

in relation to temperature 26

Figure 3.3 Iso-pentane equilibrium curve 32

Figure 3.4 2-2Dimethyl butane Equilibrium curve 33

Figure 3.5 Equilibrium Curve 33

Figure 3.6 Process Flow Diagram 42

Figure 4.1 Dependence of n-paraffins conversion on

reaction temperature 43

ix

Figure 4.2 Aluminum Oxide 47

Figure 4.3 Characteristics of chlorinated alumina

Catalysts 48

Figure 4.4 Structure and dimension of different types

of zeolite 49

Figure 4.5 Catalysts Performance Curves 49

Figure 5.1 Thermodynamic equilibrium for the isomerization

of heptane 51

Figure 5.2 Thermodynamic equilibrium for the isomerization

of Butane, pentane and hexane 52

x

NOTATIONS

Rd Fouling Factor

μ Viscosity

Cp Specific Heat

Q Heat Duty

Ux Overall Heat Transfer Coefficient

Ax Surface area for heat transfer

Fa Factor Area

Nt Number of tubes

At Area of tubes

Gt Mass velocity

ht Film coefficient

Wa Mass flow rate of air

ha Film coefficient

da Density of air

Nmin Minimum no. of stages

S Separation Factor

Rmin Minimum reflux ratio

CFS Vapor flow rate

GPM Liquid flow rate

σ Surface Tension

ρv Vapor density

ρl Liquid density

α Relative Volatility

R Reflux ratio

S Tray spacing

hct Clear liquid height

Dh Hole diameter

xi

UN Superficial vapor velocity based on net area

AN Net area

SF Derating factor

Ad Down comer top area

At Total tower cross section area

Dt Tower diameter

Af Fractional hole area

hw Outlet weir height

hcl Clearance under the down comer

T Tray deck thickness

Lw Outlet weir length

Ql Liquid load

Adt Down comer top area

Adb Down comer bottom area

Ac Active area

hd Dry plate pressure drop

Cd Orifice coefficient

Uh Velocity through holes

Ah Hole area

Aa Active area

Hr Residual head

how Liquid head over the outlet weir

tr Down comer residence time

Φ Viscosity gradient correction

K Thermal Conductivity

B Correction Factor

Y Correction Factor

F Correction Factor

Fp Air pressure drop factor

DR Density ratio

N Number of rows of tube in direction of flow

ACFM Actual cubic feet per minute

xii

NR Modified Reynolds number

AR Area ratio of fin tube

S Specific gravity

de Equivalent diameter (inch)

De Equivalent diameter (ft)

H2 Hydrogen Gas

C1 Methane

C2 Ethane

C3 Propane

n C4 Normal Butane

n C5 Normal Pentane

n C6 Normal Hexane

n C7 Normal Heptane

i C4 Iso Butane

i C5 Iso Pentane

2 MP 2 Methyl Pentane

3 MP 3 Methyl Pentane

2, 2 DMB 2, 2 Di Methyl Butane

2,3DMB 2, 3 Di Methyl Butane

2 MH 2 Methyl Hexane

3 MH 3 Methyl Hexane

2, 2 DMP 2, 2 Di Methyl Pentane




3 EP 3 Ethyl Pentane

xiii

C6H6 Benzene

C7H8 Toluene

CP Cyclo Pentane

MCP Methyl Cyclo Pentane

CH Cyclo Hexane

ECP Ethyl Cyclo Pentane

MCH Methyl Cyclo Hexane

2, 2, 3 TMB 2, 2, 3 Tri Methyl Butane

H2O Water

C2Cl4 Perchloro Ethylene

HCL Hydrochloric Acid

CHAPTER 1

INTRODUCTION

Chapter 1 Introduction

1

CHAPTER # 1

INTRODUCTION

The world of today puts great emphasis on the use of the available sources of energy

in the most economical way to meet the forthcoming challenges in the field of global

energy consumption. This has enhanced the need of not only developing methods of

efficient ways of utilizing a fuel but much more than that on developing fuels that are

more equipment friendly and environment friendly. Energy sectors are working not

only to find alternatives of conventional fossil fuels by replacing them with solar,

wind and geothermal energy sources but at the same time already existing fuels are

being made more efficient by treating them with various chemical and physical

processes.

In the field of automotive the fuel consumption is increasing day by day with the

decreasing prices of automotive for last few decades. This has forced the refinery

sector to acquire possible ways which may increase the percentage of the crude

distillate that can be used as gasoline. The gasoline cut that is obtained from the crude

oil contains hydrocarbons of C7 and C8 range. This range of hydrocarbons has better

compatibility with the operating conditions (temperature and pressure) of gasoline

engine and thus required rate of combustion is obtained in the gasoline engine using

them as fuels. This property of the fuel is distinguished by a quantity remarked as

octane number. Hence in gasoline engines a major criterion for selection of fuels is

its octane number.

For the reason mentioned above the crude refining sector turned its attention towards

the effective ways of increasing the octane number of fractions of crude distillate (not

C7and C8) by adopting different methods. The addition of small amount of TEL

(tetra ethyl lead) in the gasoline pool has a remarkable increase in the pool octane

number; this method was relatively very cheap and had been used for several years.

However the carcinogenity of the lead urged the environmental safety organizations

to put a ban on the use of TEL in the commercial gasoline. Ultimately a surge of

finding the alternative methods of increasing the octane number of the gasoline pool


2

raised in the refining sectors, methods such as Alkylation and Isomerization were

adopted for enhancing the octane ratings of the lighter ends of the crude distillate and

method of Cracking was adopted to convert heavier ends (above C8) distillate into

fractions of gasoline range. These different methods are being used in the refineries

throughout the world.

1.1 REFINERY PRODUCTS:

We shall firstly be discussing the types of the products that are obtained from a

refinery (general fractions of crude distillate) and their classification. Raw crude oil

obtained from the earth crust is pretreated to remove water and salt contents, then it is

distilled at atmospheric pressure to obtain a series of products having a specific

boiling range from 32 to 4300C.The residue from the atmospheric distillation column

is further fractionated in a vacuum distillation column. A list of these products is

given below:

Figure 1.1 Crude Distillation Products (Gary and Handwerk, 2001)

Light straight run naphtha and heavy straight run naphtha constitute about 3% to 4%

of the input crude. The range for naphtha is from C5 to C12. Light naphtha are the

hydrocarbon fractions of range C5 to C6 (including normal, iso and cyclo pentanes and

hexanes, olefins of C5 and C6 and benzene and its derivatives) whereas heavy naphtha

ranges from C7 to C10 (including gasoline, jet fuels and aviation fuels).

Crude oil is a complex liquid mixture made up of a vast number of hydrocarbon

compounds that consist mainly of carbon and hydrogen in differing proportions. In

addition, small amounts of organic compounds containing sulphur, oxygen, nitrogen

and metals such as vanadium, nickel, iron and copper are also present. Hydrogen to


3

carbon ratios affects the physical properties of crude oil. As the hydrogen to carbon

ratio decreases, the gravity and boiling point of the hydrocarbon compounds

increases.

Moreover, the higher the hydrogen to carbon ratio of the feedstock, the higher its

value is to a refinery because less hydrogen is required. The composition of crude oil,

on an elemental basis, falls within certain ranges regardless of its origin.

We shall be further discussing the types of the hydrocarbons that are obtained from

the refining of crude oil. These different hydrocarbons are then classified according to

their octane ratings. All types of crude oil give the following 4 major types of

hydrocarbons.

Paraffin

Olefins

Naphthenes

Aromatics

1.1.1 Paraffins: These are the hydrocarbons that have single bond between all carbons present in the

chain. They have a general formula of CnH2n+2. The range of carbons in this type is

from a single carbon to hundreds of carbon atoms.

These paraffins are further of two types:

a) Normal (n) paraffins

b) Iso paraffins

Normal paraffins (n-paraffins or n-alkanes) are unbranched straight-Chain molecules.

Each member of these paraffins differs from the next higher and the next lower

member by a –CH2– group called a methylene group. They have similar chemical and

physical properties, which change gradually as carbon atoms are added to the chain.

Iso paraffins (or iso alkanes) are branched-type hydrocarbons that exhibit Structural

isomerization.


4

1.1.2 Olefins:

These are the hydrocarbons that have either double or triple (at least one or more) or

both types of bondings between the carbon atoms. They have a general formula of

CnH2n.

Olefins, also known as alkenes, are unsaturated hydrocarbons containing carbon–

carbon double bonds. Compounds containing carbon–carbon triple bonds are known

as acetylenes, and are also known as biolefins or alkynes.

Olefins are not naturally present in crude oils but they are formed during the

conversion processes. They are more reactive than paraffins. The lightest alkenes are

ethylene (C2H4) and propylene (C3H6), which is important feedstock for the

petrochemical industry. The lightest alkyne is acetylene.

1.1.3 Naphthenes:

Hydrocarbons lying in this range have a cyclic or ring structure but with the limitation

that all the bonds among neighboring carbons are single, they have a general formula

of CnH2n.

The boiling point and densities of naphthenes are higher than those of alkanes having

the same number of carbon atoms. Naphthenes commonly present in crude oil are

rings with five or six carbon atoms. These rings usually have alkyl substituents

attached to them. Multi-ring naphthenes are Present in the heavier parts of the crude


5

oil. Examples of naphthenes are shown below

1.1.4 Aromatics:

These hydrocarbons have a cyclic structure along with alternative double bonds

between the carbons joined in the ring. Benzene is a six carbon containing compound

with alternative double and single bonds, benzene and its alternatives collectively

constitute this group of hydrocarbons.

Crude oils from various origins contain different types of aromatic compounds in

different concentrations. Light petroleum fractions contain mono-aromatics, which

have one benzene ring with one or more of the hydrogen atoms substituted by another

atom or alkyl groups. Examples of these compounds are toluene and xylene. Together

with benzene, such compounds are important petrochemical feedstock, and their

presence in gasoline increases the octane number.


6

1.2 AUTOMOBILE FUELS:

The wide range of the refinery products obtained are sorted to be used as the fuel for

different sectors. The cut of the refinery products used by the automobile sector is

heptane and octane. This selection is governed by the combustion properties and the

conditions provided by these engines to the fuel. One of the significant properties is

the octane number of the fuel.

1.3 OCTANE NUMBER: An octane number is a measure of the knocking tendency of gasoline fuels in spark

ignition engines. The ability of a fuel to resist auto-ignition during compression and

prior to the spark ignition gives it a high octane number.

The octane number of a fuel is determined by measuring its knocking value

compared to the knocking of a mixture of n-heptane and isooctane (2, 2, 4-rimethyl

pentane). Pure n-heptane is assigned a value of zero octane while isooctane is

assigned 100 octane. Hence, an 80 vol% isooctane mixture has an octane number of

80. Two octane tests can be performed for gasoline.

The motor octane number (MON) indicates engine performance at highway

conditions with high speeds (900 rpm).

On the other hand, the research octane number (RON) is indicative of low-speed

city driving (600 rpm).

The posted octane number (PON) is the arithmetic average of MON and RON. One

of the standard tests is ASTM D2700.


7

1.4 PROCESSING OF HEAVIER AND LIGHTER HYDROCARBONS THAN C7

AND C8:

The range commonly used in gasoline pool is the C7 and C8 hydrocarbons. However

some lighter ends and some heavier ends are converted into this range by processing

to accommodate the increasing demand of the automobile fuel. Some of the common

procedures are briefly discussed.

1.4.1 Alkylation:

The addition of an alkyl group to any compound is an alkylation reaction but in

petroleum refining terminology the term alkylation is used for the reaction of low

molecular weight olefins with an isoparaffins to form higher molecular weight

isoparaffins. Although this reaction is simply the reverse of cracking, the belief that

paraffin hydrocarbons are chemically inert delayed its discovery until about 1935.

The need for high-octane aviation fuels during World War II acted as a stimulus to the

development of the alkylation process for production of isoparaffinic gasoline of high

octane number. The need for high-octane aviation fuels during World War II acted

as a stimulus to the development of the alkylation process for production of

isoparaffinic gasoline of high octane number.

The reactions occurring in both processes are complex and the product has a rather

wide boiling range. By proper choice of operating conditions, most of the product can

be made to fall within the gasoline boiling range with motor octane numbers from 88

to 94 and research octane numbers from 94 to 99.

Alkylation processes using hydrofluoric or sulfuric acids as catalysts, only iso

paraffins with tertiary carbon atoms, such as isobutane or isopentane, react with the

olefins. In practice only isobutane is used because isopentane has a sufficiently high

octane number and low vapor pressure to allow it to be effectively blended directly

into finished gasoline.

The principal reactions which occur in alkylation are the combinations of olefins with

isoparaffins as follows:


8

The product streams leaving an alkylation unit are:

LPG grade propane liquid

Normal butane liquid

C5+ alkylate

Tar

1.4.2 Catalytic Reforming:

Catalytic reforming of heavy naphtha and isomerization of light naphtha constitute a

very important source of products having high octane numbers which are key

components in the production of gasoline, Environmental regulations limit on the

benzene content in gasoline. If benzene is present in the final gasoline it produces

carcinogenic material on combustion. Elimination of benzene forming hydrocarbons,

such as hexane will prevent the formation of benzene, and this can be achieved by

increasing the initial point of heavy naphtha. These light paraffinic hydrocarbons can

be used in an isomerization unit to produce high octane number isomers. Catalytic

reforming is the process of transforming C7–C10 hydrocarbons with low octane

numbers to aromatics and iso-paraffins which have high octane numbers. It is a highly

endothermic process requiring large amounts the straight run naphtha from the crude

distillation unit is hydrotreated to remove sulphur, nitrogen and oxygen which can all

deactivate the reforming catalyst. The hydrotreated naphtha (HTN) is fractionated into

light naphtha (LN), which Is mainly C5–C6, and heavy naphtha (HN) which is mainly


9

C7–C10 hydrocarbons. It is important to remove C6 from the reformer feed because it

will form benzene which is considered carcinogenic up on combustion. Light naphtha

(LN) is isomerized in the isomerization unit.

Light naphtha can be cracked if introduced to the reformer. Hydrogen, produced in

the reformer can be recycled to the naphtha hydrotreater, and the rest is sent to other

units demanding hydrogen.

In catalytic reforming the structure of the straight run cuts are altered by using several

techniques to make them lie within the gasoline range.

Reforming Reactions

Paraffin Dehydrogenation

Naphthene Dehydrogenation of Cyclohexanes

Isomerization

Isomerization is a mildly exothermic reaction and leads to the increase of an octane

number.

Dehydrocyclization


10

Hydrocracking Reactions

1.5 WHAT IS ISOMERIZATION:

Isomerization is the process in which light straight paraffins of low RON are

transformed into branched chain using proper catalysts. The paraffins used are C4, C5

and C6. The number of the carbon atoms remains constant but the octane number

increases. The naphtha obtained from the fractionation column of crude oil is

hydrotreated and further fractionated into heavier and light naphtha. Heavier naphtha

is (90-1900C) is used as a feed to the reforming unit. The light naphtha obtained (max

800C) is used as a feed for the isomerization unit. The reforming unit cannot treat

lighter naphtha because the C6 component of the paraffins tends to form benzene in

the reforming unit; this is an undesirable event as benzene concentrations in the

gasoline pool must be maintained down to a level because of its carcinogenity.

1.5.1 Thermodynamics of reaction:

The isomerization reactions are slightly exothermic and the reactions are carried out at

equilibrium (reversible reaction of significant level) the reaction equilibrium is

unaffected by the pressure variation as the number of moles on both sides remain

same. However kinetic studies have shown that a temperature of 125-1300C is

optimum for the reaction to be carried out.


11

Figure 1.2

1.5.2 Isomerization Reactions:

Isomerization is a reversible and slightly exothermic reaction:

The conversion to iso-paraffin is not complete since the reaction is equilibrium

conversion limited. It does not depend on pressure, but it can be increased by

lowering the temperature. However operating at low temperatures will decrease the

reaction rate. For this reason a very active catalyst must be used.

1.5.3 Isomerization Catalysts:

There are two types of isomerization catalysts

The standard Pt/chlorinated alumina

The Pt/zeolite catalyst.

Standard Isomerization Catalyst (Pt/chlorinated alumina)

This bi-functional nature catalyst consists of highly chlorinated alumina (8–15w%

chlorine) responsible for the acidic function of the catalyst. Platinum is deposited

(0.3–0.5 wt%) on the alumina matrix. Platinum in the presence of hydrogen will

prevent coke deposition, thus ensuring high catalyst activity. The reaction is

performed at low temperature at about 1300C.

To improve the equilibrium yield and to lower chlorine elution. The standard

isomerization catalyst is sensitive to impurities such as water and sulphur traces which


12

will poison the catalyst and lower its activity. For this reason, the feed must be

hydrotreated before isomerization. Furthermore, carbon tetrachloride must be injected

in to the feed to activate the catalyst. The pressure of the hydrogen in the reactor will

result in the elution of chlorine from the catalyst as hydrogenchloride. For all these

reasons, the zeolite catalyst, which is resistant to impurities, was developed.

1.5.4 Zeolite Catalyst:

Zeolites are crystallized silico-aluminates that are used to give an acidic function to

the catalyst. Metallic particles of platinum are impregnated on the surface of zeolites

and act as hydrogen transfer centres. The zeolite catalyst can resist impurities and

does not require feed pretreatment, but it does have lower activity and thus the

reaction must be performed at a higher temperature of 2500C. A comparison of the

operating conditions for the alumina and zeolite processes is shown

Figure 1.3 Comparison of operating Conditions of Catalyst

CHAPTER 2

ISOMERIZATION TECHNIQUES

Chapter 2 Isomerization Techniques

13

CHAPTER # 2

INTRODUCTION

2.1 UOP‘S PENEX PROCESS:

The Penex process has served as the primary isomerization technology for upgrading

C5/C6 light straight-run naphtha feeds since UOP introduced it in 1958. This process

has a wide range of operating configurations for optimum design flexibility and

feedstock processing capabilities.

The Penex process is a fixed-bed procedure that uses high activity chloride-promoted

catalysts to isomerize C5/C6 paraffins to higher octane branched components. The

reaction is conducted in the presence of a minor amount of hydrogen. Even though the

chloride is converted to hydrogen chloride, carbon steel construction is used

successfully because of the dry environment. For typical C5/C6 feeds, equilibrium will

limit the product to 83 to 86 RON (Research Octane Number) on a single

hydrocarbon pass basis.

The operating conditions are such that promote isomerization and minimize

hydrocracking. Operating conditions are not severe, as reflected by moderate

operating pressure, low temperature, and low hydrogen partial pressure requirements.

Ideally, this isomerization catalyst would convert all the feed paraffins to the high

octane-number branched structures: normal pentane (nC5) to isopentane (iC5) and

normal hexane (nC6) to 2,2- and 2,3-dimethylbutane. The reaction is controlled by a

thermodynamic equilibrium that is more favorable at low temperature.

Equipments Used in Penex Process:

Methanator feed effluent exchanger

Methanator feed steam exchanger

Methanator

Methanator knockout drum

Make-up gas dryers (2 in number)

Liquid feed dryer (2 in number)

Regenerant super heater


14

Regenerant evaporator

Liquid feed surge drum

Charge pump (2 in number)

Chloride drum

Chloride injection pump (2 in number)

Combine feed exchanger (3 in number)

Reactors (2 in number)

Stabilizer column

Stabilizer re-boiler

Stabilizer overhead air cooler

Stabilizer overhead trim cooler

Stabilizer overhead separator

Stabilizer reflux pump (2 in number)

Net gas scrubber

Caustic circulation pump (2 in number)

Caustic tank

Water circulation pump (2 in number)

Water Tank

Water injection pump (2 in number)

Operation and Operating Conditions of some Penex Process Equipment:

2.1.1 Liquid Feed Driers Operation:

Hydro treated SR light naphtha at temperature 45 0C & pressure 4.5 kg/cm

2 is passed

through driers to control moisture at 1.0 ppmw in the feed. Drying medium is the

molecular sieves. There are two drier, one remain in operation while the other is on

regeneration. Isomerate is used as regenerant. Dry liquid feed is collected in feed

surge drum. Molecular sieves are regenerated by isomerate & there replacement

depends on the efficiency or after period of four year.

2.1.2 Make Up Gas Driers Operation:

Make up gas is dry by passing into dryers. Molecular sieves used as drying agents.

Dry gas is control at moisture < 1.0 ppmv. Before drying of gas CO & CO2 is


15

removed from the makeup gas. It is accomplished by passing the gas through

Methanator. CO & CO2 are converted into methane in presence of Nickel oxide

catalyst. Nickel catalyst cannot be regenerated. It is replaced totally; its life is 4-5

years. Temperature & pressure of Methanator is maintained 220 °C & 27 kg/cm2.

2.1.3 Reactor Operations:

Combine liquid feed & make up gas is heated in pre-heat exchangers & chloride is

injected before entering the reactors. The Reactor System is typically designed to

operate at a minimum pressure of 31.6 Kg/cm2

(g). Lead reactor inlet temperatures

range from 131°C to 200°C and lag reactor inlet temperatures range from 142°C to

186°C. H2/HCBN mole ratio is maintained as 0.20 at reactors inlet & 0.05 at reactors

outlet.

2.1.4 Stabilizer Operation:

Reactor effluents passed through stabilizer where lighter gases & propane is separated

from the isomerate. Stabilizer column is operated at temperature 145 °C & pressure

18.0 kg/cm2.

2.1.5 Stabilizer Net Gas Scrubber Operation:

The purpose of net gas scrubbers is that to neutralize the net gas prior sending to fuel

gas header with caustic (strength is 10%wt). Operating parameters of net scrubbers is

that pressure is 6.5 kg/cm2 and temperature is 45 °C.

The most common Penex process is Hydrocarbon Once-Through Penex process.

2.1.6 Hydrocarbon Once-Through Penex Process:

Figure 2.1


16

2.1.6.1 Process Description:

Hydrogen Once-Through Penex process flow scheme results in a substantial saving in

capital equipment and utility costs by eliminating product separator and recycle gas

compressor.

Light naphtha feed is charged to one of the two dryer vessels. These vessels are filled

with molecular sieves, which remove water and protect the catalyst. After mixing with

makeup hydrogen, the feed is heat-exchanged against reactor effluent. It then enters a

charge heater before entering the reactors.

Typically, two reactors in series are used to achieve high on-stream efficiency. The

catalyst can be replaced in one reactor while operation continues in the other. One

characteristic of the process is that catalyst deactivation begins at the inlet of the first

Reactor and proceeds slowly as a rather sharp front downward through the bed. The

adverse effect that such deactivation can have on unit on-stream efficiency is avoided

by installing two reactors in series. Each reactor contains 50% of the total required

catalyst. Piping and valving are arranged to permit isolation of the reactor containing

the spent catalyst while the second reactor remains in operation. After the spent

catalyst has been replaced, the relative processing positions of the two reactors are

reversed. During the short time when one reactor is off-line for catalyst replacement,

the second reactor is fully capable of maintaining continuous operation at design

throughput, yield, and conversion.

The reactor effluent flows to stabilizer after passing through the heat exchanger. The

stabilizer overhead vapors are caustic scrubbed for removal of the HCl formed from

organic chloride added to the reactor feed to maintain catalyst activity. After

scrubbing, the overhead gas then flows to fuel. The stabilized, isomerized liquid

product from the bottom of the column then passes to gasoline blending.

The Penex process (see below) uses the most active chlorided-alumina catalyst and

operates in the range 120-180°C.


17

LHSV is set during the design phase of any isomerization project and reflects the

compromise between residence time and overall catalyst cost. At lower LHSVs, more

catalyst is loaded resulting in a longer residence time. As a result lower temperature

Operation is possible, resulting in a higher octane product.

System pressure is another variable and is considered in conjunction with the

hydrogen flow rate to the reactor. Chlorided-alumina is more active at higher

pressures. It requires only a slight excess over stoichiometric hydrogen, since the

catalyst does not produce coke. A Penex unit operates at about 30 to 32 bar with once-

through hydrogen.

Figure 2.2 (Block flow diagram of ―one through‖ process)

To achieve higher octane, UOP offers several schemes in which lower octane

components are separated and recycled back to the reactors. These recycle modes of

operation can lead to product octane as high as 93 RON.

2.1.7 Penex Process/DIH (De-isoHexanizer):

This flow scheme is same as Penex Process with an addition of deisohexanizer

column to recycle the methylpentanes, n-hexane, and some C6 cyclics. It is the lowest

cost option of the recycle flow schemes & provide high octane isomerate product,

especially on C6 rich feed.


18

Figure 2.3 (Block flow diagram of process with DIP)

2.1.8 Penex Process With Recycle And Fractionation (DIP/Penex Process/DIH):

Separation and recycle of unconverted normal C5 and C6 paraffins and low octane C6

isoparaffins back to the reactor, produce a higher octane product. The most common

flow scheme uses a deisohexanizer (DIH) column to recycle methylpentanes, n-

hexane, and some C6 cyclics. It is the lowest capital cost option of the recycle flow

schemes and provides a higher octane isomerate product, especially on C6 rich feeds.

In the Penex/DIH process the stabilized isomerate is charged to a DIH column

producing an overhead product containing all the C5 and dimethylbutanes. Normal

hexane and some of the methylpentanes are taken as a side-cut and recycled back to

the reactors. The small amount of bottoms (C7+ and some C6 cyclics) can be sent to

gasoline blending or to a reformer

.

The addition of a deisopentanizer (DIP) or a super DIH will achieve the highest

octane from a fractionation hydrocarbon recycle flow scheme. In this scheme, both

low octane C5 and normal and isoparaffin C6 are recycled to the Penex reactors.

Figure 2.4 (DIP-Penex-DIH)


19

2.1.9 Penex/Molex Process:

Figure 2.5 (Penex/Molex Process flow scheme)

2.2 PROCESS DESCRIPTION:

This flow scheme uses Molex technology for the economic separation and recycle of

n-paraffin from the reactor effluent.

The Molex process is an adsorptive separation method that utilizes molecular sieves

for the separation of n-paraffins from branched and cyclichydrocarbons. The

separation is effected in the liquid phase under isothermal conditions according to the

principles of the UOP Sorbex separations technology. Because the separation takes

place in the liquid phase, heating, cooling and power requirements are remarkably

low.

Sorbex is the name applied to a particular technique developed by UOP for separating

a component or group of components from a mixture in the liquid phase by selective

adsorption on a solid adsorbent.

Sorbex is a simulated moving bed adsorption process operating with all process

streams in the liquid phase and at constant temperature within the adsorbent bed. Feed

is introduced and components are adsorbed and separated from each other within the

bed. A separate liquid of different boiling point referred to as ‗desorbent‘ is used to


20

displace the feed components from the pores of the adsorbent. Two liquid streams

emerge from the bed – an extract and a raffinate stream, both diluted with desorbent.

The desorbent is removed from both product streams by fractionation and is recycled

to the system.

The adsorbent is fixed while the liquid streams flow down through the bed. A shift in

the positions of liquid feed and withdrawal, in the direction of fluid flow through the

bed, simulates the movement of solid in the opposite direction. It is, of course,

impossible to move the liquid feed and withdrawal points continuously. However,

approximately the same effect can be produced by providing multiple Liquid access

lines to the bed, and periodically switching each net stream to the next adjacent line.

A liquid circulating pump is provided to pump liquid from the bottom outlet to the top

inlet of the adsorbent chamber. A fluid-directing device, known as a ‗rotary valve‘, is

also provided.

Figure 2.6 (BFD of Molex Process)

2.2.1 Operating Conditions Of Molex Process:

Molex unit involves three processes.

a) Adsorption

b) Purification

c) Desorption


21

2.2.1.1 Adsorption Operation:

The adsorbent employed in Molex is a specially prepared molecular sieve with

selective pores. Molex feed enter the adsorbent chamber via rotary valve. Adsorbent

chamber is operated at pressure 15 kg/cm2.

2.2.1.2 Purification Operation:

Non-normal paraffins (iso-paraffins) are removed from the adsorption chamber &

purified in raffinate column. Operating temperature & pressure of raffinate column is

125 °C & 13.0 kg/cm2.

2.2.1.3 Desorption:

Operating temperature & pressure of the extract column 130 °C & 16.0 kg/cm2.

2.2.2 Penex-Plus Technology

The performance of the Penex process can be compromised when processing this

feedstock because benzene hydrogenation is a highly exothermic reaction. The heat

generated by the benzene hydrogenation reaction can cause the reactors to operate at

conditions that are less favorable for octane upgrading. For these applications, UOP

offers the Penex-Plus Technology.

It includes two reactor sections. The first section is designed to saturate the benzene to

cyclohexane. The second section is designed to isomerize the feed for an overall

octane increase. Each reactor is operated at conditions that favor the intended

reactions for maximum conversion.


22

2.3 OCTANE COMPARISON FOR DIFFERENT PROCESSES:

Figure 2.7 (Octane Comparison for different Processes) {Feed RON = 60 to 70

CHAPTER 3

PROCESS DESCRIPTION

Chapter 3 Process Description

23

CHAPTER # 3

PROCESS DESCRIPTION

3.1 SIMPLE PROCESS DESCRIPTION:

The isomerization of light paraffins is an important industrial process to obtain

branched alkanes which are used as octane boosters in gasoline. Thus, isoparaffins are

considered an alternative to the use of oxygenate and aromatic compounds, whose

maximum contents are subjected to strict regulations in order to protect the

environment.

The UOP‘s Penex process is specifically designed for the catalytic isomerization of

pentane, hexanes, and mixtures thereof. The reactions take place in the presence of

hydrogen, over a fixed bed of catalyst, and at operating conditions that promote

isomerization and minimize hydrocracking. Operating conditions are not severe,

reaction takes place at moderate operating pressure, low temperature, and low

hydrogen partial pressure is required.

Light naphtha feed is charged to one of the two dryer vessels. These vessels are filled

with molecular sieves, which remove water and protect the catalyst. After mixing with

makeup hydrogen, the feed is heat-exchanged against reactor effluent. It then enters a

charge heater before entering the reactors. Two reactors normally operate in series.

The reactor effluent is cooled before entering the product stabilizer. Only a slight

excess of hydrogen above chemical consumption is used. The makeup hydrogen,

which can be of any reasonable purity, is typically provided by a catalytic reformer.

The stabilizer overhead vapors are caustic scrubbed for removal of the HCl formed

from organic chloride added to the reactor feed to maintain catalyst activity. After

scrubbing, the overhead gas then flows to fuel. The stabilized, isomerized liquid

product from the bottom of the column then passes to gasoline blending.

Ideally, this isomerization catalyst would convert all the feed paraffins to the high

octane- number branched structures: normal pentane (nC5) to isopentane (iC5) and


24

normal hexane (nC6) to 2,2- and 2,3-dimethylbutane. The reaction is controlled by a

thermodynamic equilibrium that is more favorable at low temperature.

With C5 paraffins, interconversion of normal pentane and isopentane occurs. The C6-

paraffin isomerization is somewhat more complex. Because the formation of 2- and 3-

methylpentane and 2,3-dimethylbutane is limited by equilibrium, the net reaction

involves mainly the conversion of normal hexane to 2,2-dimethylbutane. All the feed

benzene is hydrogenated to cyclohexane, and a thermodynamic equilibrium is

established between methylcyclopentane and cyclohexane. The octane rating shows

an appreciation of some 14 numbers.

3.2 PROCESS CHEMISTRY:

Isomerization mechanism and Kinetics Paraffin isomerization is most effectively

catalyzed by a dual-function catalyst containing a noble metal and an acid function.

The reaction is believed to proceed through an olefin intermediate that is formed by

the dehydrogenation of the paraffin on the metal site. We use butane for simplicity

CH3 — CH2 — CH2 — CH3 ↔ CH3 — CH2 — CH ═ CH2 + H2

These dual-functional hydro-isomerization catalysts which operate at very low

temperatures have stronger acid site. In this case it is possible that the necessary

carbonium ion is former by direct hydride ion abstraction from the paraffin by the

acid function of the catalyst:

CH3 — CH2 — CH ═ CH2 + [H+][A

-] → CH3 — CH2 — CH

+ — CH3 + A

Then carbonium ion undergoes skeletal isomerization. However this reaction proceeds

with difficulty because it requires the formation of a primary carbonium ion at some

point in the reaction. Nevertheless, the strong acidity of the isomerization catalyst

provides enough driving force for the reaction to proceed at high rates.

+ +

CH3 — CH2 — CH — CH3 → CH3 — C — CH3

│

CH3

The isoparaffinic carbonium ion is then converted to an olefin through loss of a proton

to the catalyst site.


25

+

CH3 — C — CH3 + A- → CH3 — C ═ CH2 + [H

+][A

-]

│ │

CH3 CH3

In the last step, the isoolefin intermediate is hydrogenated rapidly back to the

analogous isoparaffin:

CH3 — C ═ CH2 + H2 → CH3 — CH — CH3

│ │

CH3 CH3

Equilibrium limits the maximum conversion possible at any given set of conditions.

This maximum is a strong function of the temperature at which the conversion takes

place. A more favorable equilibrium exists at lower temperatures.

Figure 3.1 shows the equilibrium plot for the pentane system. The maximum

isopentane content increases from 64 mol % at 260°C to 82 mol % at 120°C (248°F).

Neopentane and cyclopentane have been ignored because they seem to occur only in

small quantities and are not formed under isomerization conditions.

The hexane equilibrium curve shown in Figure 3.2 is somewhat more complex than

that shown in Fig. 3.3. The methylpentanes have been combined because they have

nearly the same octane rating. The methylpentane content in the C6-paraffin fraction

remains nearly constant over the entire temperature range. Similarly, the fraction of

2,3-dimethylbutane is almost constant at about 9 mol % of the C6 paraffins.

Theoretically, as the temperature is reduced, 2,2-dimethylbutane can be formed at the

expense of normal hexane. This reaction is highly desirable because nC6 has a RON

of 30. The RON of 2,2- dimethylbutane is 93.


26

Figure 3.1 C5 paraffin equilibrium plot

Figure 3.2 Equilibrium composition of hexane isomers in relation to temperature.

3.3 REACTIONS:

The C5/C6 paraffin isomerization reactions which occur in Penex unit are shown

below:


27

3.3.1 Hexane Reactions

Normal Hexane 2-Methyl Pentane

CH3

CH3—CH2—CH2—CH2—CH2—CH3 ↔ CH3—CH—CH2—CH2—CH3

24.8 RON 73.4 RON

3-Methyl Pentane

CH3

CH3—CH2—CH2—CH2—CH2—CH3 ↔ CH3—CH2—CH—CH2—CH3

74.5 RON

2-2 Dimethyl Butane

CH3

CH3—CH2—CH2—CH2—CH2—CH3 ↔ CH3—C—CH2—CH3

CH3

91.8 RON

2-3 Dimethyl Butane

CH3

CH3—CH2—CH2—CH2—CH2—CH3 ↔ CH3—CH—CH—CH3

CH3

104.3RON


28

3.3.2 Pentane Reaction

Normal Pentane Iso-Pentane CH3

CH3—CH2—CH2—CH2—CH3 ↔ CH3—CH—CH2—CH3

61.8 RON 93.0 RON

3.3.2 Other Reactions

Apart from the paraffins isomerization reactions, there are several other important

reactions including:

Naphthene Ring Opening

Naphthene Isomerization

Benzene Saturation

Hydrocracking

3.3.2.2 Ring Openinig:

The three naphthenes which are typically present in feed are cyclopentane (CP),

methyl cyclopentane (MCP) and cyclohexane (OH). The naphthene rings will

hydrogenate to form paraffins. This ring opening reaction increases with increasing

reactor temperature. At typical isomerization reactor conditions the conversion of

naphthenes rings to paraffins will be on the order of 20-40 percent.


29

3.3.2.3 Naphthene Isomerization:

The naphthenes Methyl Cyclopentane (MCP) and Cyclo Hexane (CH) exists in

equilibrium. Naphthene isomerization will shift towards MCP production as

temperature is increased.

3.3.2.4 Benzene Saturation:

The catalyst will saturate benzene to cyclohexane. This reaction proceeds very

quickly and is achieved at very low temperatures. Saturation a benzene is not

equilibrium limited at the isomerization reactor conditions ant conversion should be

100%. The amount of heat generated by the saturation of benzene limits the amount

of benzene which can be tolerated in the feed. The isomerization section feed can

contain up to 5% benzene. The platinum function on the isomerization catalyst is

responsible for benzene saturation.

3.3.2.5 Hydrocracking:

Hydrocracking occurs in the reactors to a degree which depends on the feed quality

and severity of operation. Large molecules such a C7‘s tend to hydrocrack more easily

than smaller molecules. C5 and C6 paraffin will also hydrocrack to a certain extent. As

C5/C6 paraffin isomerization approaches equilibrium, the extent of hydrocracking

increases. If isomerization is pushed too hard, hydrocracking will reduce the liquid

yield and increase heat production. Methane, ethane, propane and butane are produced

as a result of hydrocracking.


30

Normal Heptane Propane i Butane CH3

CH3—CH2—CH2—CH2—CH2—CH2—CH3 → CH3—CH2—CH3 + CH3—CH—CH3

3.3.3 Chloride promoter:

The addition of the chloride promoter (perchloroethylene C2Cl4) to the process stream

is intended to maintain the acid function of the catalyst with chloride atoms (Cl). At a

reactor temperature of 105°C (220°F) or higher, the organic chloride will decompose

to HCl in the presence of the catalyst.

Perchloroethylene + Hydrogen → Hydrogen Chloride + Ethane

C2Cl4 + 5H2 → 4HCl + C2H6

3.3.4 Caustic Scrubbing Reactions:

The hydrogen chloride formed in the isomerization reactors is neutralized in the

Stabilizer Net Gas Scrubber, by means of an acid-base reaction between sodium

hydroxide (NaOH) and hydrogen chloride (HCl). The result of this neutralization

reaction is sodium chloride (NaCl) and water. The strength of the caustic should be

monitored by determining the total alkalinity of the solution. Report the concentration

of strong base as wt% NaOH.

HCl + NaOH NaCl + H2O

3.4 PROCESS VARIABLES:

In the normal operation of a Penex Unit, having once set the operating pressure fresh

feed rate and makeup hydrogen flows, it is usually only necessary to adjust the reactor

inlet temperatures.

Once the catalyst has been loaded into the unit, the manner in which the catalyst it

placed in seance and the treatment it receives when in service will to a large extent

influence its effectiveness for making quality product as well as the length of service


31

it will give. In making any changes to the operation, the welfare of the catalyst must

be given prime consideration for it can be regarded as the heart of the operation or

which the quality of the results obtained will depend.

3.4.1 Reactor Temperature:

In general, reactor temperature is the main process control. A definite upper limit

exists for the amount of iso-paraffins which can exist in the reactor product at any

given outlet temperature, as shown in Figures 3.3, 3.4 and 3.5. This is the equilibrium

imposed by thermodynamics, and can be reached only after an infinity length of time,

i.e. with an infinitely large reactor. In practice, therefore, the product will contain less

than this equilibrium concentration of iso-paraffins. As reactor temperature is raised

to increase the rate of isomerization, the equilibrium composition will be approached

more closely. At excessively high temperatures, the concentration of iso-paraffins in

the product will actually decrease because of the downward shift in equilibrium curve,

even though the high temperature gives a high reaction rate.

The use of temperatures higher than necessary to achieve a reasonably close approach

to equilibrium accomplishes nothing other than to increase the amount of

hydrocracking. Extremely high temperatures may lead to an increased rate of carbon

laydown on the catalyst; however, the carbon forming propensity of the catalyst is

inherently so low that excessive hydrocracking would normally be encountered before

carbon formation problems would develop. It is recommended, however, that UOP be

consulted before temperatures above about 204°C (400°F) are employed.

A typical C5/C6 Penex Unit has two series reactors with provision for independent

temperature control. The first reactor system effects the bulk of the isomerization so

long as most of the catalyst therein is still active. Any benzene in the feed it

hydrogenated in the first reactor, even when the catalyst therein has lost its activity

with respect to paraffin isomerization. Some conversion, ring opening, of cyclohexane

and methyl Cyclopentane to hexanes also occurs, as does some hydrocracking of C7 to

C3 and C4. These three reactions (benzene hydrogenation, naphthene ring opening to

hexane, and C7 hydrocracking) are exothermic and, for a typical feed stock contribute

more to the temperature rise in the first reactor that does paraffin isomerization, which

is also exothermic.


32

Normally, the first reactor system will be operated at such a temperature as to

maximize the concentration of isopentane and 2,2 dimethyl butane in its effluent. The

concentrations attainable and the required outlet temperature will be influenced by the

amount of active catalyst present and by the amount of C6 cyclic and C7 components

present in the feed, higher the temperatures being required with high concentrations of

these components in the feed. By this procedure, the required operating temperature

on the second reactor system is reduced and it is possible to operate under conditions

where the equilibrium is more favorable.

Figure 3.3 Iso-pentane equilibrium curve


33

Figure 3.4 2-2Dimethyl butane Equilibrium curve

Figure 3.5 Equilibrium Curve


34

3.4.2 Liquid Hourly Space Velocity:

This term, commonly shortened to LHSV, is defined as the volumetric hourly flow of

reactor charge divided by the volume of catalyst contained in the reactors in

consistent units. The design LHSV for C5/C6 Penex operation is normally between 1

and 2. Increasing the LHSV beyond this will lead to lower product isomer ratios.

In order to avoid excessive reactor severity, the Penex reactor LHSV should always

be maintained above 0.5 hr-1

overall or 1.0 LHSV minimum per reactor.

3.4.3 Hydrogen to Hydrocarbon Mole Ratio:

This ratio is defined as the number of moles hydrogen at the reactor outlet per mole of

reactor charge passing over the catalyst, and is specified at 0.05 moles H2/mole

HCBN. The primary purpose of maintaining the ratio at or above the design is to

avoid carbon deposition on the catalyst and maintain enough H2 for the reactions to

proceed. If necessary, the reactor charge rate is to be reduced to maintain the design

hydrogen to hydrocarbon ratio. The H2/HCBN ratio is determined by measuring the

total mole of hydrogen in the stabilizer overhead gas and dividing by the total moles

of fresh feed feedstock.

3.4.4 Pressure:

C5/C6 Penex Units are normally designed to operate at 31.6 kg/cm2

gauge (450 psig)

at the reactor outlet. Methylcyclopentane and cyclohexane appear to adsorb on the

catalyst and reduce the rate of isomerization reactions. Higher pressure helps to offset

this effect of the C6 cyclic compounds. Lowering the unit pressure or operating at a

slightly lower level would not affect the catalyst life but the extent of isomerization

would be influenced.

3.4.5 Catalyst Promoter:

To sustain catalyst activity, the addition of chloride is necessary. At no time should

the plant be operated for longer than six hours without the injection of chloride.

Whenever there is a catalyst chloride deficiency, the product isomer ratios will

decrease (although not necessarily instantaneously), other things being equal.

Restarting the injection of chloride will tend to return the activity of the catalyst to its

previous level, but it is possible that full activity will not be restored if a decline in


35

activity as a result no chloride injection has been observed. Isomerization grade

perchloroethylene (C2Cl4) is UOP's recommended source of chloride.

3.5 PROCESS EQUIPMENTS:

3.5.1 Sulfur Guard Bed:

The purpose of the sulfur guard bed is to protect the Penex catalyst from sulfur in the

liquid feed. The hydrotreater will remove most of the sulfur in the Penex feed. The

guard bed reduces the sulfur to a safe level for operation and serves as insurance

against upsets in the NHT which could result in higher that formal level of sulfur in

the feed.

The guard bed is loaded with an adsorbent, a nickel containing extrudate designed to

chemisorb sulfur from the liquid feed. The feedstock is heated to the required

temperature for sulfur removal, usually 121 °C (250°F), and passed down flow over

the adsorbent.

Once sulfur breakthrough occurs, normally after one year or so of operation, the guard

bed is taken off line and reloaded with fresh adsorbent. The Penex Unit need not be

shut down during the short period of time required to reload the guard bed so long as

the NHT is performing properly.

3.5.2 Liquid Feed Driers:

The purpose of the liquid feed driers is to ensure that the hydrocarbon stream from the

treating section is dry before entering the Penex Unit.

The driers are operated in series except when they are in the regeneration mode when

at that time only one will be in service.

The hydrotreated C5/C6 stream is introduced to the liquid feed drier at the bottom and

passes up flow through the molecular sieve desiccant and exits at the top. The flow is

then routed through one of the drier crossovers to the other liquid feed drier. The flow

through the liquid feed drier is also in the up flow pattern. The dried hydrocarbon is

then routed to feed surge drum. Over a period of time, the drier in the lead position


36

will become spent as indicated by the moisture analyzer located between the two

driers. At this time, it will become necessary to regenerate this drier. The driers

should be regenerated on a schedule frequent enough to avoid moisture breakthrough.

The spent drier is taken out of service by closing the appropriate block valves. The

second series drier is now alone in service as the only drier drying the feed. The

moisture analyzer tap is switched to monitor this in service drier. After the drier

regeneration has been completed, it is now ready for service. A switch is made such

that the regenerated drier takes the tail position with the in-service drier remaining as

the lead drier. Over a period of time the lead drier will become spent and is now set

up far regeneration with the tail drier now being the only one in service. This will be

the manner in which these driers will be lined up for process flow.

3.5.3 Make-up Gas Driers:

Make-up gas must be dried in order to protect the catalyst. The two gas driers operate

in the same manner as the liquid feed driers. The driers operate up flow, in series. The

dried hydrogen is then sent to the reactor circuit on flow control. The hydrogen is also

used for pressure control in the feed surge drum and, for startup, in the stabilizer.

3.5.4 Feed Surge Drum:

The purpose of this drum is to provide liquid feed surge capacity for the Penex Unit.

Dried feed from the liquid feed driers is routed to this drum. The feed surge drum is

blanketed with dry hydrogen gas originating from the outlet of the make-up gas driers

with the feed surge drum pressure being controlled by a PRC.

3.5.5 Reactor Exchanger Circuit:

The dried liquid feed from the feed surge drum is pumped by either of the t reactor

charge pumps through the reactor exchanger circuit on flow control. The reactor

exchanger circuit consists of the cold combined feed exchanger, the hot combined

feed exchanger and the reactor charge heater.

Prior to the entry of the liquid hydrocarbon into the cold combined feed exchanger, it

combines with the makeup hydrogen stream. After combining, the mix hydrocarbon-


37

hydrogen stream passes through the exchanger circuit in the order previously

mentioned.

The cold combined feed exchanger is equipped with a bypass which can be used to

regulate the amount of combined feed preheat. The bypass is regulated with a board

mounted control valve to maintain reactor charge heater control. The combined feed

is further preheated by exchange with a portion of the lead reactor effluent in the hot

combined feed exchanger.

A small quantity of catalyst promoter (perchloroethylene) is added upstream of the

reactor charge heater. This promoter is pumped into the process by either of two

injection pumps. The catalyst promoter is stored in a nitrogen blanketed storage drum.

The combined feed is finally brought up to the desired temperature in the reactor

charge heater by a temperature controller which resets the exchanger‘s heat medium

flow. The charge heater is equipped with an automatic shutdown which is activated by

low feed or low makeup gas flow.

After exiting the reactor charge heater, the heated combined stream then flows into

the first reactor.

3.5.6 Regenerant Vaporizer:

The regenerant vaporizer uses low pressure steam to heat the regenerant stream before

it reaches the electric superheater. The vaporizer is an upright heat exchanger which

uses bayonet type tubes that have been strength welded and fully rolled. This heater is

equipped with a level indicator and a high level alarm, and is designed to operate with

the top portion of the tubes uncovered. Low pressure steam on the inside of the

bayonet tubes transfers heat to the regenerant on the outside of the bayonet tubes. This

arrangement allows hot stream in the tip of the bayonet tube to transfer heat to the

vaporized regenerant stream, giving it several degrees of superheat. This prevents the

regenerant from condensing which could damage the electric bundles in the super

heater when operating.


38

3.5.7 Regenerant Superheater:

The regenerant superheater, raises the temperature of the vaporized regenerate to a

temperature of 315°C (600°F). The regenerant stream is heated by Inconel electric

elements, which are capable of reaching temperatures of over 600°C (1112°F).The

regenerant entering the superheater must be in the vapor phase to avoid damaging the

electric bundles when power is applied to the superheater.

3.5.8 Isomerization Reactors:

The reactors are the heart of the process. The operation of them is such that, reactor

will be placed in series with the other reactor. At various times throughout the unit's

history it will be possible to have either reactor in the lead or tail position. A single

reactor bypass allows operation of one reactor only during startup or partial catalyst

replacement. Thermocouples are inserted into the catalyst bed of each reactor to

monitor the activity of the catalyst in conjunction with product ratios.

After exiting the reactor charge heater, the heated combined stream then flows to the

first reactor. Upon exiting the first reactor, the stream then passes to the hot combined

feed exchanger where the first reactor's heat of reaction is partially removed. The

degree of temperature removal can be achieved by adjusting the amount of exchanger

by-passing with a temperature controller. This temperature controller fixes the lag

reactor's inlet temperature.

The partially cooled stream is then routed to the second reactor where the find process

reactions are completed.

The reactors are equipped with hydrogen purge lines which are located at the inlet of

each reactor. The hydrogen purge is used to remove hydrocarbon from a reactor

which is to be unloaded or to pressurize a reactor. A hydrogen quench line is located

at the lead reactor inlet header to aid in cooling the catalyst during a temperature

excursion as well as removing hydrocarbon. The quench is controlled by an HIC with

flow indication.


39

In case of a high reactor temperature emergency, the reactors are equipped with

depressuring lines to the flare system. The reactors are depressured from the outlet of

the lag reactor. The depressuring line is equipped with two motorized o pneumatically

operated valves which can be operated from the control room once the reactors have

been isolated from the charge heater and stabilizer.

After exiting the second reactor, the stream is then routed to the tube side of the cold

combined feed exchanger. The cold combined feed exchanger tube side effluent is

then routed to the stabilizer on pressure control.

3.5.9 Stabilizer:

The purpose of this column is to separate any dissolved hydrogen, HCI and cracked

gases (C1, C2, and C3's) from the isomerate.

The feed to this column is routed hot directly from the cold CFX before entering the

stabilizer.

The column is reboiled by either steam or hot oil. The reboiler heat input is controlled

by an FRC on the heating medium. The amount of heat input is adjusted to maintain

sufficient reflux to adequately strip the HCl and light ends from the stabilizer bottoms

material. The typical design external reflux to feed ratio is approximately 0.5 on a

volume basis and is recommended as a starting point.

The stabilizer column overhead vapor, consisting of the light hydrocarbon

components of the column's feed, is routed to an air or water cooled condenser and

then to the stabilizer receiver. To maintain pressure control on the column, gas is

vented on pressure control to the stabilizer gas scrubber. Liquid is pumped from the

receiver on level control with the stabilizer reflux pump. All liquid from the stabilizer

overhead receiver is refluxed to the column on tray No. 1.

Bottoms product is routed to storage on level control after first being cooled in the

stabilizer bottoms cooler. If the stabilizer bottoms is sent to a deisohexanizer it is not

cooled, but is charged hot to the column. Part of the stabilizer bottoms is used for

regenerating the driers.


40

3.5.10 Stabilizer Net Gas Scrubber:

The function of the Stabilizer Net Gas Scrubber is to neutralize the hydrogen chloride

present in the Stabilizer off Gas prior to its entry into the fuel gas system o the flare

header. The HCI is formed in the reactor section and then vented off through the

Stabilizer Overhead Receiver, to the Stabilizer Net Gas Scrubber.

In this vessel, the off gas from the Stabilizer Receiver is contacted through a liquid

level and later with a counter current flow of caustic solution (10 wt. % NaOH) which

reacts with HCl to form sodium chloride and water. The entry point for the off gas is

located at the bottom of the scrubber, and consists of a monel distributor with small

holes to allow even gas distribution. The bottom distributor and the inlet flange are

both made of monel to prevent corrosion, resulting from contact with high

concentrations of HCl in an aqueous environment. The vessel is constructed of killed

carbon steel.

The top portion of the vessel is filled with 25mm (1‘‘) Carbon Raschig Rings, which

provide a good contact area for the interaction of the liquid caustic and the acidic

overhead gas. The packing in the scrubbing section is held in place by a support

orating on the bottom and a hold down grating on the top.

The incoming gas is contacted with the caustic in the bottom portion of the scrubber

or "reservoir" section. This is where most of the HCl is removed before it reaches the

top portion or the scrubbing section of the column. A high level of caustic solution is

usually kept in the reservoir section of the column to ensure that there is always an

ample supply of caustic for circulation. A pump is used to circulate the caustic to the

two infection points on the scrubber column. One injection point if located at the top

of the packed section (a spray nozzle or slot type distributor) ant the other is located

just below the packed section (a spray nozzle or ring type distributor). The purpose of

the lower spray distributor is to direct the caustic flow to the conical walls of the

scrubber to keep the walls wetted with caustic. The design flow of caustic should be

continuously maintained to each distributor to ensure goof flow distribution.


41

A water wash section may be included above the circulating caustic to remove

entrained caustic from the net gas. Circulating water monitored by an FI is passed

over a bed of 25mm (1‘‘) Carbon Raschig Rings at design rate. Makeup water is

added to overflow a chimney trap tray which replaces water lost to saturating the dry

gas in the caustic inventory section. The water is typically changed out if the caustic

strength reaches 2 wt. % NaOH in the circulating water or if caustic entrainment is

observed.

3.5.11 Pumps:

Centrifugal pumps are used for several applications in the Penex Unit. Common

applications for the centrifugal pumps are for reactor charge pumps, reflux pumps for

the fractionation columns, and caustic recirculation pumps. Proportioning pumps are

used for chloride injection into the feed stream and make-up water to the net gas

scrubber.

Pumps used in hydrocarbon service use tandem seals with API 52 seal plans. In this

application the seal oil circulation is established by way of a siphon. The seal oil is

contained in a reservoir where it can be pumped to and from the pump seal. The oil is

continuously pumped between the two seals. In the event of a seal failure,

hydrocarbon will leak into the oil system and cause a pressure increase in the

reservoir. The seal oil reservoir is equipped with a pressure alarm and pressure gauge

to alert the operator to a seal failure. The reservoir is usually vented to flare through

an orifice plate.

CHAPTER 4

CATALYST SELECTION

Chapter 4 Catalyst Selection

43

CHAPTER # 4

CATALYST SELECTION

4.1 CATALYST:

Substance that changes the rate of reaction but does not take part in reaction.

4.2 TYPES OF CATALYSTS:

The schemes of proposing processes are analogous generally. The differences are

defines by performances of usable catalysts due to their type. Main parameter which

is the octane number of produced isomerate depends on process temperature. That‘s

why we will dwell on the issue of thermodynamic of isomerization reaction. First of

all hydrocarbons isomerization reaction is balanced reaction, and equilibrium yield of

isoparaffins increases with temperature reducing, but it can be reached only after an

―infinite residence time‖ of the feed in reaction zone or an equivalent very small value

for LHSV. On the other hand an increase in temperature always corresponds to an

increase in reaction velocity. So that at low temperature the actual yield will be far

below the equilibrium yield, because of low reaction velocity. On the contrary, at

higher temperature, the equilibrium yield will be more easily reached, due to a high

reaction rate. Consequently, at higher temperature the yield of isoparaffins is limited

by the thermodynamic equilibrium, and at lower temperature it is limited by low

reaction rate (kinetic limitation) (Figure 4.1)

Figure 4.1 Dependence of n-paraffins conversion on reaction temperature


44

Paraffin-isomerization catalysts fall mainly into two principal categories: those based

on Friedel-Crafts catalysts as classically typified by aluminum chloride and hydrogen

chloride and dual-functional hydro isomerization catalysts.

4.2.1 First Generation Catalysts:

The Friedel-Crafts catalysts represented a first-generation system. Although they

permitted operation at low temperature, and thus a more favorable isomerization

equilibrium, they lost favor because these systems were uneconomical and difficult to

operate. High catalyst consumption and a relatively short life resulted in high

maintenance costs and a low on-stream efficiency.

4.2.2 Second Generation Catalysts:

These problems of first generation systems were solved with the development of

second-generation dual-functional hydro isomerization catalysts. These catalysts

included a metallic hydrogenation component in the catalyst and operated in a

hydrogen environment. However, they had the drawback of requiring a higher

operating temperature than the Friedel-Crafts systems.

4.2.3 Third Generation Catalysts:

The desire to operate at lower temperatures, at which the thermodynamic equilibrium

is more favorable, dictated the development of third-generation catalysts. The

advantage of these low-temperature [below 200°C (392°F)] catalysts contributed to

the relative nonuse of the high-temperature versions. Typically, these noble-metal,

fixed-bed catalysts contain a component to provide high catalytic activity. They

operate in a hydrogen environment and employ a promoter. Because hydrocracking of

light gases is slight, liquid yields are high.

An improved version of these third-generation catalysts is used in the Penex process.

Paraffin isomerization is most effectively catalyzed by a dual-function catalyst

containing a noble metal and an acid function. The reaction is believed to proceed

through an olefin intermediate that is formed by the dehydrogenation of the paraffin

on the metal site.


45

4.2.4 Aluminum Chloride:

The isomerization catalysts employed during World War II were all of the Friedel

Crafts type. Those which contained aluminum chloride only were either a

hydrocarbon/aluminum chloride complex (the so-called sludge process) or they were

manufactured in-situ by deposition onto a support such as alumina or bauxite. They

were intended to operate at very low temperatures [49-129°C (120-265°F)] and to

approach the very favorable equilibrium composition characteristic of these

temperatures.

The catalyst tended to consume itself by reaction with the feedstock and/or product.

When temperature was raised a little in an effort to compensate for loss of catalyst

and to speed the reaction to effect more isomerization, light fragments were formed

by cracking and these, when vented caused an excessive loss of the HCI promoter.

Corrosion of downstream equipment was also commonplace, due to the solubility of

aluminum chloride in hydrocarbon, to its relatively high volatility and to the difficulty

of removing it from the product by caustic washing. Aluminum chloride deposition in

and plugging of reboiler tubes was not uncommon.

4.3 DUAL-FUNCTIONAL HYDROISOMERIZATION CATALYSTS:

4.3.1 Hydro-isomerization catalysts [above 199°c (390°f)]: The operational problems which had characterized the Friedel-Crafts type

isomerization plants, the advent of catalytic reforming which not only made hydrogen

generally available in refineries but also demonstrated the practicality of using noble

metal containing catalysts on a large scale, and the octane numbed race which postwar

high compression engines initiated all combined in the 1950's to spawn a spate of

hydro-isomerization processes. These catalysts generally contained a noble metal and

some halide, operated at temperatures between about 299°C (560°F) and

temperatures approaching those characteristic of catalytic reforming, employed

recycle hydrogen to prevent catalyst carbonization and utilized either no promoter or

traces at most. In general, they did not require an especially dry feedstock but did

benefit from a low sulfur content feedstock. Most achieved a close approach to the

equilibrium characteristic of their particular operating temperature.


46

Because of their high operating temperatures and their necessarily low conversions to

iso-paraffins, these high temperature catalysts were quickly replaced with the advent

of the ―third generation‖ low temperature catalysts.

4.3.2 Hydro-isomerization catalysts [below 199°c (390°f)]: Low temperature is considered rather arbitrarily for catalyst classification purposes as

anything below 199°C (390°F) operating temperature. Typically these are fixed bed

catalysts containing a supported noble metal and a component to provide acidity in

the catalytic sense. They operate in a hydrogen atmosphere and may employ a catalyst

promoter whose concentration in the reactor may range from parts per million to

substantially higher levels. They generally all require a dry, low sulfur feedstock;

however, they may differ importantly in their tolerance of certain types and molecular

weights of hydrocarbons. Hydrocracking to light gases is generally slight, so liquid

product yields are high. The type of catalyst used in the Penex unit is of this type.

The acid function is the support itself and some examples include acid zeolites,

chlorided alumina and amorphous silica alumina. Noble metals have a positive effect

on the activity and stability of the catalyst. However they have a low resistance to

poisoning by sulfur and nitrogen compounds present in the processed cuts.

In order to prepare a suitable catalyst for hydroconversion of alkanes, good balance

between the metal and acid functions must be obtained. Rapid molecular transfer

between the metal and acid sites is necessary for selective conversion of alkanes into

desirable products.

4.4 ALUMINA CATALYST:

Alumina or aluminum oxide (AlR2ROR3R) is a chemical compound with melting

point of about 2000°C and sp. gr. of about 4.0. It is insoluble in water and organic

liquids and very slightly soluble in strong acids and alkalies. Alumina occurs in two

crystalline forms. Alpha alumina is composed of colorless hexagonal crystals with the

properties given above; gamma alumina is composed of minute colorless cubic


47

crystals with sp. gr. of about 3.6 that are transformed to the alpha form at high

temperatures. Figure (4.2) shows the shape of AlR2ROR3R [Ulla, 2003].

The most common form of crystalline alumina, α-aluminum oxide, is known as

corundum. If a trace of the element is present it appears red, it is known as ruby, but

all other colorations fall under the designation sapphire. The primitive cell contains

two formula units of aluminum oxide. The oxygen ions nearly form a hexagonal

close-packed structure with aluminum ions filling two-thirds of the octahedral

interstices.

Typical alumina characteristics include:

Good strength and stiffness

Good hardness and wear resistance

Good corrosion resistance

Good thermal stability

Excellent dielectric properties (from DC to GHz frequencies)

Low dielectric constant

Low loss tangent

Figure 4.2 Aluminum Oxide


48

4.5 CHLORINATED-ALUMINA BASED CATALYSTS: These are the most active and supply the highest isomerize yield and isomerize

octane.

Figure 4.3 Characteristics of chlorinated alumina catalysts

4.6 ZEOLITES:

Zeolites are micro porous crystalline solids with well-defined structures. Generally

they contain silicon, aluminum and oxygen in their framework and cations, water

and/or other molecules within their pores. Zeolites occur naturally as minerals or

synthetic, Figure (4.3) shows the shape of different types of zeolites [Matthew, 2008].

Because of their unique porous properties, zeolites are used in a variety of

applications with a global market of several million tons per annum. In the western

world, major uses are in petrochemical cracking, ion-exchange (water softening and

purification), and in the separation and removal of gases and solvents. Other

applications are in agriculture, animal husbandry and construction. They are often

also referred to as molecular sieves [Danny, 2002].

Zeolites have the ability to act as catalysts for chemical reactions which take place

within the internal cavities. An important class of reactions is that catalyzed by

hydrogen-exchanged zeolites, whose framework-bound protons give rise to very high

acidity. This is exploited in many organic reactions, including crude oil cracking,

isomerization and fuel synthesis [Jirong, 1990].

4.5.1 Zeolite Characteristics:

Well-defined crystalline structure.

High internal surface areas (>600 mP2P/g).


49

Uniform pores with one or more discrete sizes.

Good thermal stability.

Highly acidic sites when ion is exchanged with protons.

Ability to sorb and concentrate hydrocarbons.

Figure 4.4 Structure and dimension of different types of zeolite

Figure 4.5

CHAPTER 5

MATERIAL BALANCE

Chapter 5 Material Balance

50

CHAPTER # 5

MATERIAL BALANCE

5.1 Material Balance:

Material balances are important first step when designing a new process or analyzing

an existing one. They are almost always prerequisite to all other calculations in the

solution of process engineering problems.

Material balances are nothing more than the application of the law of conservation of

mass, which states that mass can neither be created nor destroyed. Thus, you cannot,

for example, specify an input to a reactor of one ton of naphtha and an output of two

tons of gasoline or gases or anything else. One ton of total material input will only

give one ton of total output,

i.e. total mass of input = total mass of output.

5.1.1 Conservation Law:

+ = + ±

The quantity S can be any one of the following quantities:

Mass

Energy

Momentum

Component Mass (Mole)

5.1.2 Total Mass Balance: Since mass is always conserved, the balance equation for the total mass (m) of a given

system is:

Rate of mass in - Rate of mass out = rate of mass accumulation 5.1.3 Component Balance: The mass balance for a component A is generally written in terms of number of moles

of A. Thus the component balance is:

Flow of Flow of Rate of Rate of

moles (A) + mole of (A) + Generation of = Accumulation of

in out moles of (A) moles of (A)

Total flow rate of (S) into the system

Generation rate of (S) within system

Amount of (S) exchanged with the surrounding

Total flow rate of (S) out of the system

Accumulation rate of (S) within system


51

Basis:

Naphtha Feed Stream

600 Barrel of Naphtha per stream day to be Isomerized

Mass flow rate = 25000 kg/hr

Molecular Weight = 83.085

Density = 660 kg/m3

Hydrogen Feed Stream

Mass flow rate = 732 kg/hr

Molecular Weight = 7.907

Density = 1.215 kg/m3

Equilibrium Data: Equilibrium Conversions are taken from the following curves

Figure 5.1 Thermodynamic equilibrium for the isomerization of heptane


52

Figure 5.2 Thermodynamic equilibrium for the isomerization of Butane, pentane and hexane


53

5.2 Mass Balance on Mixer

Stream 3

Components Molecular

Mass

Mass

Fraction

Mass Flow

Rate

Molar Flow

Rate

n C4 58.00 0.0267 667.50 11.51

n C 5 72.00 0.1673 4182.50 58.09

n C 6 86.00 0.1589 3971.25 46.18

n C7 100.00 0.0929 2321.75 23.22

i C 5 72.00 0.1077 2693.25 37.41

2 MP 86.00 0.0750 1875.25 21.81

3 MP 86.00 0.0482 1204.25 14.00

2,2 DMB 86.00 0.0056 138.75 1.61

2,3DMB 86.00 0.0121 301.75 3.51

2 MH 100.00 0.0373 931.65 9.32

3 MH 100.00 0.0373 931.40 9.31

2,2 DMP 100.00 0.0027 68.40 0.68

2,3 DMP 100.00 0.0112 279.15 2.79

2,4 DMP 100.00 0.0057 141.65 1.42

3,3 DMP 100.00 0.0018 43.93 0.44

3 EP 100.00 0.0028 69.90 0.70

C6H6 78.00 0.0253 632.50 8.11

C7H8 92.00 0.0288 719.25 7.82

CP 70.00 0.0118 295.50 4.22

MCP 84.00 0.0400 998.75 11.89

CH 84.00 0.0387 967.25 11.51

ECP 98.00 0.0028 70.00 0.71

MCH 98.00 0.0598 1494.50 15.25

Total 1.00 25000.08 301.51


54

Stream 2


Mass

Volume

fraction

Mole

Fraction Mass

Mass

Fraction Mass Flow

Rate

Molar Flow Rate

H2 2 0.78 0.780 1.56 0.1980 144.91 72.4569

C1 16 0.099 0.099 1.58 0.2010 147.14 9.1964

C2 30 0.064 0.064 1.92 0.2437 178.36 5.9452

C3 44 0.038 0.038 1.67 0.2122 155.32 3.5299

n-C4 58 0.008 0.008 0.46 0.0589 43.10 0.7431

i-C4 58 0.008 0.008 0.46 0.0589 43.10 0.7431

n-C5 72 0.002 0.002 0.14 0.0183 13.38 0.1858

i-C5 72 0.001 0.001 0.07 0.0091 6.69 0.0929

Total 1.00 1.00 7.88 1.00 732.00 92.8934

Stream 4


Mass

Mass

Fraction

Mole

Fraction

Mass Flow

Rate

Molar Flow

Rate

H2 2.00 0.0056 0.1837 144.91 72.4569 C1 16.00 0.0057 0.0233 147.14 9.1964 C2 30.00 0.0069 0.0151 178.36 5.9452 C3 44.00 0.0060 0.0090 155.32 3.5299

n C4 58.00 0.0276 0.0311 710.60 12.2518 n C 5 72.00 0.1631 0.1478 4195.88 58.2761

n C 6 86.00 0.1543 0.1171 3971.25 46.1773

n C7 100.00 0.0902 0.0589 2321.75 23.2175

i-C4 58.00 0.0017 0.0019 43.10 0.7431

i C 5 72.00 0.1049 0.0951 2699.94 37.4991 2 MP 86.00 0.0729 0.0553 1875.25 21.8052 3 MP 86.00 0.0468 0.0355 1204.25 14.0029

2,2 DMB 86.00 0.0054 0.0041 138.75 1.6134 2,3DMB 86.00 0.0117 0.0089 301.75 3.5087

2 MH 100.00 0.0362 0.0236 931.65 9.3165 3 MH 100.00 0.0362 0.0236 931.40 9.3140

2,2 DMP 100.00 0.0027 0.0017 68.40 0.6840 2,3 DMP 100.00 0.0108 0.0071 279.15 2.7915 2,4 DMP 100.00 0.0055 0.0036 141.65 1.4165 3,3 DMP 100.00 0.0017 0.0011 43.93 0.4393

3 EP 100.00 0.0027 0.0018 69.90 0.6990 C6H6 78.00 0.0246 0.0206 632.50 8.1090

C7H8 92.00 0.0280 0.0198 719.25 7.8179 CP 70.00 0.0115 0.0107 295.50 4.2214

MCP 84.00 0.0388 0.0301 998.75 11.8899 CH 84.00 0.0376 0.0292 967.25 11.5149 ECP 98.00 0.0027 0.0018 70.00 0.7143

MCH 98.00 0.0581 0.0387 1494.50 15.2500

Total 1.00 1.00 25732.08 394.40


55

5.3 Material Balance around Reactors:


56

Stream 7

Components

Molecular

Mass Mass

Fraction Mole

Fraction Mass Flow

Rate Molar Flow

Rate

H2 2.00 0.0056 0.1837 144.91 72.4569

C1 16.00 0.0057 0.0233 147.14 9.1964

C2 30.00 0.0069 0.0151 178.36 5.9452

C3 44.00 0.0060 0.0090 155.32 3.5299

n C4 58.00 0.0276 0.0311 710.60 12.2518

n C 5 72.00 0.1631 0.1478 4195.88 58.2761

n C 6 86.00 0.1543 0.1171 3971.25 46.1773

n C7 100.00 0.0902 0.0589 2321.75 23.2175

i-C4 58.00 0.0017 0.0019 43.10 0.7431

i C 5 72.00 0.1049 0.0951 2699.94 37.4991

2 MP 86.00 0.0729 0.0553 1875.25 21.8052

3 MP 86.00 0.0468 0.0355 1204.25 14.0029

2,2 DMB 86.00 0.0054 0.0041 138.75 1.6134

2,3DMB 86.00 0.0117 0.0089 301.75 3.5087

2 MH 100.00 0.0362 0.0236 931.65 9.3165

3 MH 100.00 0.0362 0.0236 931.40 9.3140

2,2 DMP 100.00 0.0027 0.0017 68.40 0.6840

2,3 DMP 100.00 0.0108 0.0071 279.15 2.7915

2,4 DMP 100.00 0.0055 0.0036 141.65 1.4165

3,3 DMP 100.00 0.0017 0.0011 43.93 0.4393

3 EP 100.00 0.0027 0.0018 69.90 0.6990

C6H6 78.00 0.0246 0.0206 632.50 8.1090

C7H8 92.00 0.0280 0.0198 719.25 7.8179

CP 70.00 0.0115 0.0107 295.50 4.2214

MCP 84.00 0.0388 0.0301 998.75 11.8899

CH 84.00 0.0376 0.0292 967.25 11.5149

ECP 98.00 0.0027 0.0018 70.00 0.7143

MCH 98.00 0.0581 0.0387 1494.50 15.2500

H2O 18.00 0.0000 0.0000 0.00 0.0000

C2Cl4 94.00 3.000E-06 0.0000 7.50E-05 7.98E-07

Total 1.00 1.00 25732.08 394.40


57

Stream 8


Mass Mass

Fraction Mole

Fraction Mass Flow

Rate Molar Flow

Rate

H2 2.00 0.0013 0.0482 32.6411 16.3205

C1 16.00 0.0057 0.0272 147.4071 9.2129

C2 30.00 0.0070 0.0177 179.3759 5.9792

C3 44.00 0.0062 0.0107 159.0078 3.6138

n C4 58.00 0.0137 0.0180 353.4739 6.0944

n C 5 72.00 0.0394 0.0416 1013.8848 14.0817

n C 6 86.00 0.0362 0.0320 932.4828 10.8428

n C7 100.00 0.0072 0.0055 185.7398 1.8574

i-C4 58.00 0.0154 0.0202 396.9166 6.8434

i C 5 72.00 0.2321 0.2451 5971.2138 82.9335 2 MP 86.00 0.1192 0.1054 3066.6213 35.6584 3 MP 86.00 0.0730 0.0646 1879.3603 21.8530

2,2 DMB 86.00 0.0455 0.0403 1171.2736 13.6195 2,3DMB 86.00 0.0287 0.0254 738.5866 8.5882

2 MH 100.00 0.0600 0.0457 1545.0732 15.4507 3 MH 100.00 0.0497 0.0378 1279.6610 12.7966

2,2 DMP 100.00 0.0162 0.0123 416.6620 4.1666 2,3 DMP 100.00 0.0307 0.0233 789.9341 7.8993 2,4 DMP 100.00 0.0136 0.0104 350.6071 3.5061 3,3 DMP 100.00 0.0116 0.0088 299.3171 2.9932

3 EP 100.00 0.0045 0.0034 116.3349 1.1633 C6H6 78.00 0.0000 0.0000 0.6325 0.0081 C7H8 92.00 0.0000 0.0000 0.7192 0.0078 CP 70.00 0.0080 0.0087 206.8498 2.9550

MCP 84.00 0.0252 0.0228 649.1867 7.7284 CH 84.00 0.0663 0.0601 1707.1082 20.3227 ECP 98.00 0.0027 0.0021 69.9999 0.7143

MCH 98.00 0.0733 0.0569 1886.2642 19.2476 2,2,3 TMB 100.00 0.0072 0.0055 185.7398 1.8574

H2O 18.00 0.0000 0.0000 0.0000 0.0000 C2Cl4 94.00 1.00E-06 0.0000 0.0257 0.0003 HCL 36.50 2.30E-05 0.0000 0.5918 0.0162

Total 1.00 1.0000 25732.69 338.32


58


59

Stream 9

Components

Molecular

Mass

Mass

Fraction

Mole

Fraction

Mass Flow

Rate

Molar Flow

Rate

H2 2.00 0.0013 0.0482 32.6411 16.3205

C1 16.00 0.0057 0.0272 147.4071 9.2129

C2 30.00 0.0070 0.0177 179.3759 5.9792

C3 44.00 0.0062 0.0107 159.0078 3.6138

n C4 58.00 0.0137 0.0180 353.4739 6.0944

n C 5 72.00 0.0394 0.0416 1013.8848 14.0817

n C 6 86.00 0.0362 0.0320 932.4828 10.8428

n C7 100.00 0.0072 0.0055 185.7398 1.8574

i-C4 58.00 0.0154 0.0202 396.9166 6.8434

i C 5 72.00 0.2321 0.2451 5971.2138 82.9335

2 MP 86.00 0.1192 0.1054 3066.6213 35.6584

3 MP 86.00 0.0730 0.0646 1879.3603 21.8530

2,2 DMB 86.00 0.0455 0.0403 1171.2736 13.6195

2,3DMB 86.00 0.0287 0.0254 738.5866 8.5882

2 MH 100.00 0.0600 0.0457 1545.0732 15.4507

3 MH 100.00 0.0497 0.0378 1279.6610 12.7966

2,2 DMP 100.00 0.0162 0.0123 416.6620 4.1666

2,3 DMP 100.00 0.0307 0.0233 789.9341 7.8993

2,4 DMP 100.00 0.0136 0.0104 350.6071 3.5061

3,3 DMP 100.00 0.0116 0.0088 299.3171 2.9932

3 EP 100.00 0.0045 0.0034 116.3349 1.1633

C6H6 78.00 0.0000 0.0000 0.6325 0.0081

C7H8 92.00 0.0000 0.0000 0.7192 0.0078

CP 70.00 0.0080 0.0087 206.8498 2.9550

MCP 84.00 0.0252 0.0228 649.1867 7.7284

CH 84.00 0.0663 0.0601 1707.1082 20.3227

ECP 98.00 0.0027 0.0021 69.9999 0.7143

MCH 98.00 0.0733 0.0569 1886.2642 19.2476

2,2,3 TMB 100.00 0.0072 0.0055 185.7398 1.8574

H2O 18.00 0.0000 0.0000 0.0000 0.0000

C2Cl4 94.00 1.00E-06 0.0000 2.57E-02 2.74E-04

HCL 36.50 2.30E-05 0.0000 5.92E-01 1.62E-02

Total 1.00 1.0000 25732.69 338.32


60

Stream 10

Hydrogen to Hydrocarbon Ratio at the outlet of R-102

Should be 0.05

H2 : HC Ratio 0.05

Components

Molecular

Mass

Mass

Fraction

Mole

Fraction

Mass Flow

Rate

Molar Flow

Rate

H2 2.00 0.0013 0.0479 32.3827 16.1914

C1 16.00 0.0057 0.0272 147.1509 9.1969

C2 30.00 0.0069 0.0176 178.3647 5.9455

C3 44.00 0.0060 0.0104 155.3259 3.5301

n C4 58.00 0.0041 0.0054 106.5960 1.8379

n C 5 72.00 0.0079 0.0083 202.8658 2.8176

n C 6 86.00 0.0029 0.0026 74.6026 0.8675

n C7 100.00 0.0004 0.0003 9.2875 0.0929

i-C4 58.00 0.0251 0.0330 647.1486 11.1577

i C 5 72.00 0.2637 0.2787 6784.4979 94.2291

2 MP 86.00 0.1293 0.1144 3327.8947 38.6965

3 MP 86.00 0.0781 0.0691 2010.0155 23.3723

2,2 DMB 86.00 0.0600 0.0531 1544.3494 17.9576

2,3DMB 86.00 0.0323 0.0286 831.8794 9.6730

2 MH 100.00 0.0605 0.0460 1556.3009 15.5630

3 MH 100.00 0.0510 0.0388 1313.1645 13.1316

2,2 DMP 100.00 0.0173 0.0132 446.4043 4.4640

2,3 DMP 100.00 0.0325 0.0247 836.4138 8.3641

2,4 DMP 100.00 0.0142 0.0108 365.4858 3.6549

3,3 DMP 100.00 0.0124 0.0094 317.9081 3.1791

3 EP 100.00 0.0049 0.0037 125.6286 1.2563

C6H6 78.00 0.0000 0.0000 0.0019 0.0000

C7H8 92.00 0.0000 0.0000 0.0026 0.0000

CP 70.00 0.0080 0.0087 206.8608 2.9552

MCP 84.00 0.0252 0.0229 649.2215 7.7288

CH 84.00 0.0663 0.0601 1707.1996 20.3238

ECP 98.00 0.0027 0.0021 70.0037 0.7143

MCH 98.00 0.0733 0.0569 1886.3652 19.2486

2,2,3 TMB 100.00 0.0077 0.0059 198.7522 1.9875

H2O 18.00 0.0000 0.0000 0.0000 0.0000

C2Cl4 94.00 1.00E-06 0.0000 0.0257 0.0003

HCL 36.50 2.30E-05 0.0000 0.5918 0.0162

Total 1.00 1.0000 25732.69 338.14


61

5.4 Material Balance around Stabilizer T 101:


62

Stream 11

Components

Molecular

Mass

Mass

Fraction

Mole

Fraction

Fraction

Mass Flow

Rate

Molar Flow

Rate

H2 2.00 0.0013 0.0479 32.3835 16.1917

C1 16.00 0.0057 0.0272 147.1544 9.1971

C2 30.00 0.0069 0.0176 178.3689 5.9456

C3 44.00 0.0060 0.0104 155.3296 3.5302

n C4 58.00 0.0041 0.0054 106.5985 1.8379

n C 5 72.00 0.0079 0.0083 202.8706 2.8176

n C 6 86.00 0.0029 0.0026 74.6044 0.8675

n C7 100.00 0.0004 0.0003 9.2877 0.0929

i-C4 58.00 0.0251 0.0330 647.1641 11.1580

i C 5 72.00 0.2637 0.2787 6784.6607 94.2314

2 MP 86.00 0.1293 0.1144 3327.9746 38.6974

3 MP 86.00 0.0781 0.0691 2010.0637 23.3728

2,2 DMB 86.00 0.0600 0.0531 1544.3865 17.9580

2,3DMB 86.00 0.0323 0.0286 831.8994 9.6732

2 MH 100.00 0.0605 0.0460 1556.3382 15.5634

3 MH 100.00 0.0510 0.0388 1313.1960 13.1320

2,2 DMP 100.00 0.0173 0.0132 446.4150 4.4641

2,3 DMP 100.00 0.0325 0.0247 836.4339 8.3643

2,4 DMP 100.00 0.0142 0.0108 365.4946 3.6549

3,3 DMP 100.00 0.0124 0.0094 317.9158 3.1792

3 EP 100.00 0.0049 0.0037 125.6316 1.2563

C6H6 78.00 0.0000 0.0000 0.0019 0.0000

C7H8 92.00 0.0000 0.0000 0.0026 0.0000

CP 70.00 0.0080 0.0087 206.8658 2.9552

MCP 84.00 0.0252 0.0229 649.2371 7.7290

CH 84.00 0.0663 0.0601 1707.2405 20.3243

ECP 98.00 0.0027 0.0021 70.0053 0.7143

MCH 98.00 0.0733 0.0569 1886.4105 19.2491

2,2,3 TMB 100.00 0.0077 0.0059 198.7570 1.9876

H2O 18.00 0.0000 0.0000 0.0000 0.0000

C2Cl4 94.00 1.000E-06 8.096E-07 2.573E-02 2.738E-04

HCL 36.50 2.300E-05 4.795E-05 5.919E-01 1.622E-02

Total 1.00 1.0000 25733.31 338.15


63

Stream 13


Mass

Mass

Fraction

Mole

Fraction

Mass Flow

Rate

Molar Flow

Rate

H2 2.00 0.0245 0.3332 32.6412 16.3206

C1 16.00 0.1105 0.1881 147.4076 9.2130

C2 30.00 0.1344 0.1221 179.3766 5.9792

C3 44.00 0.1191 0.0738 159.0084 3.6138

n C4 58.00 0.0779 0.0366 103.9217 1.7918

i-C4 58.00 0.4828 0.2268 644.3509 11.1095

i C 5 72.00 0.0508 0.0192 67.8235 0.9420

C2Cl4 94.00 1.000E-06 8.970E-07 2.440E-02 2.595E-04

HCL 36.50 2.300E-05 5.313E-05 5.611E-01 1.537E-02

Total 1.00 1.00 1335.12 48.99

Stream 14

Components

Molecular

Mass

Mass

Fraction

Mole

Fraction

Mass Flow

Rate

Molar Flow

Rate

n C4 58.00 0.0001 0.0001 2.1210 0.0366

n C 5 72.00 0.0083 0.0097 202.7881 2.8165

n C 6 86.00 0.0031 0.0030 74.6027 0.8675

n C7 100.00 0.0004 0.0003 9.2875 0.0929

i C 5 72.00 0.2752 0.3223 6714.8678 93.2621

2 MP 86.00 0.1364 0.1337 3327.8996 38.6965

3 MP 86.00 0.0824 0.0808 2010.0184 23.3723

2,2 DMB 86.00 0.0633 0.0621 1544.3517 17.9576

2,3DMB 86.00 0.0341 0.0334 831.8807 9.6730

2 MH 100.00 0.0638 0.0538 1556.3032 15.5630

3 MH 100.00 0.0538 0.0454 1313.1664 13.1317

2,2 DMP 100.00 0.0183 0.0154 446.4049 4.4640

2,3 DMP 100.00 0.0343 0.0289 836.4150 8.3642

2,4 DMP 100.00 0.0150 0.0126 365.4864 3.6549

3,3 DMP 100.00 0.0130 0.0110 317.9086 3.1791

3 EP 100.00 0.0051 0.0043 125.6288 1.2563

C6H6 78.00 0.0000 0.0000 0.0019 0.0000

C7H8 92.00 0.0000 0.0000 0.0026 0.0000

CP 70.00 0.0085 0.0102 206.8611 2.9552

MCP 84.00 0.0266 0.0267 649.2224 7.7288

CH 84.00 0.0700 0.0702 1707.2021 20.3238

ECP 98.00 0.0029 0.0025 70.0038 0.7143

MCH 98.00 0.0773 0.0665 1886.3680 19.2487

2,2,3 TMB 100.00 0.0081 0.0069 198.7525 1.9875

H2O 18.00 0.000E+00 0.0000 0.0000 0.0000

Total 1.00 1.00 24397.55 289.35


64

5.5 MATERIAL BALANCE AROUND SCRUBBER:

Material Balance Around Scrubber T-102

/ hr 48.75

kmole

/hr

Stream 16 0.59 kg / hr

0.02 kmole/hr

Stream 13 1334.53 kg / hr

48.75 kmole/hr


65

Stream 13


Mass Mass

Fraction Mole

Fraction Mass Flow

Rate Molar Flow

Rate

H2 2.00 0.0245 0.3332 32.6412 16.3206

C1 16.00 0.1105 0.1881 147.4076 9.2130

C2 30.00 0.1344 0.1221 179.3766 5.9792

C3 44.00 0.1191 0.0738 159.0084 3.6138

n C4 58.00 0.0779 0.0366 103.9217 1.7918

i-C4 58.00 0.4828 0.2268 644.3509 11.1095

i C 5 72.00 0.0508 0.0192 67.8235 0.9420 C2Cl4 94.00 1.000E-06 8.970E-07 2.440E-02 2.595E-04

HCL 36.50 2.300E-05 5.313E-05 5.611E-01 1.537E-02

Total 1.00 1.00 1335.12 48.99

Stream 15


Mass Mass

Fraction Mole

Fraction Mass Flow

Rate Molar Flow

Rate

H2 2.00 0.0245 0.3332 32.6412 16.3206

C1 16.00 0.1105 0.1881 147.4076 9.2130

C2 30.00 0.1344 0.1221 179.3766 5.9792

C3 44.00 0.1191 0.0738 159.0084 3.6138

n C4 58.00 0.0779 0.0366 103.9217 1.7918

i-C4 58.00 0.4828 0.2268 644.3509 11.1095

i C 5 72.00 0.0508 0.0192 67.8235 0.9420 C2Cl4 94.00 0.0000 0.0000 0.0000 0.0000

HCL 36.50 0.0000 0.0000 0.0000 0.0000

NaCl 40.00 2.400E-05 5.403E-05 5.855E-01 1.563E-02

Total 1.00 1.00 1335.12 48.99

CHAPTER 6

ENERGY BALANCE

Chapter 6 Energy Balance

66

CHAPTER # 6

ENERGY BALANCE

The First Law of Thermodynamics is a statement of energy conservation. Although

energy cannot be created or destroyed, it can be converted from one form to another

(for example, internal energy stored in molecular bonds can be converted into kinetic

energy; potential energy can be converted to kinetic or to internal energy, etc.).

Energy can also be transferred from one point to another, or from one body to a

second body. Energy transfer can occur by flow of heat, by transport of mass

(transport of mass is otherwise known as convection), or by performance of work.

The general energy balance for a process can be expressed in words as:

Accumulation of Energy in System =

Input of Energy into System – Output of Energy from System

6.1 ENERGY BALANCE AROUND REACTOR R-101:


67

6.1.1 Molar Composition

Components STREAM IN STREAM OUT

Mol% Mol%

H2 18.3713 4.8240

C1 2.3317 2.7232

C2 1.5074 1.7673

C3 0.8950 1.0682

n C4 3.1064 1.8014

n C 5 14.7758 4.1623

n C 6 11.7082 3.2049

n C7 5.8868 0.5490

i-C4 0.1884 2.0228

i C 5 9.5079 24.5136

2 MP 5.5287 10.5400 3 MP 3.5504 6.4593 2,2 DMB 0.4091 4.0257 2,3DMB 0.8896 2.5385 2 MH 2.3622 4.5669 3 MH 2.3616 3.7824 2,2 DMP 0.1734 1.2316 2,3 DMP 0.7078 2.3349 2,4 DMP 0.3592 1.0363 3,3 DMP 0.1114 0.8847 3 EP 0.1772 0.3439

C6H6 2.0560 0.0024

C7H8 1.9822 0.0023 CP 1.0703 0.8734 MCP 3.0147 2.2844 CH 2.9196 6.0070 ECP 0.1811 0.2111 MCH 3.8666 5.6892 223TMB 0.0000 0.5490 H2O 0.0000 0.0000 C2Cl4 0.0000 0.0001

HCL 0.00E+00 4.79E-03


68

6.1. 2 Heat of Formation

Components ∆Hf° Reactants ∆Hf°Products

Heat of formation at 25 C

ni ∆Hf° ni∆Hf° ni ∆Hf° ni∆Hf°

kmol/hr kJ/kmole kJ/hr kmol/hr kJ/kmole kJ/hr

H2 72.49 0 0.00 16.32 0 0.00

C1 9.20 -74900 -689130.06 9.21 -74900 -690056.81

C2 5.95 -84738 -504013.73 5.98 -84738 -506670.71

C3 3.53 -103890 -366894.77 3.61 -103890 -375443.21

n C4 12.26 -126190 -1546760.31 6.09 -126190 -769057.96

n C 5 58.30 -146490 -8540779.57 14.08 -146490 -2062855.48

n C 6 46.20 -167290 -7728550.98 10.84 -167290 -1813915.64

n C7 23.23 -187890 -4364338.62 1.86 -187890 -348990.26

i-C4 0.74 -134590 -100066.10 6.84 -134590 -921061.70

i C 5 37.52 -154590 -5799653.70 82.93 -154590 -12820832.96

2 MP 21.82 -174390 -3804360.11 35.66 -174390 -6218533.77

3 MP 14.01 -171690 -2405262.73 21.85 -171690 -3751986.83

2,2 DMB 1.61 -185690 -299724.59 13.62 -185690 -2529025.09

2,3DMB 3.51 -177890 -624452.89 8.59 -177890 -1527774.43

2 MH 9.32 -195090 -1818390.34 15.45 -195090 -3014315.96

3 MH 9.32 -192390 -1792743.05 12.80 -192390 -2461966.49

2,2 DMP 0.68 -206290 -141167.13 4.17 -206290 -859541.38

2,3 DMP 2.79 -199390 -556852.69 7.90 -199390 -1575066.62

2,4 DMP 1.42 -202090 -286391.89 3.51 -202090 -708549.55

3,3 DMP 0.44 -201690 -88633.00 2.99 -201690 -603699.30

3 EP 0.70 -189790 -132724.11 1.16 -189790 -220794.33

C6H6 8.11 82977 673167.24 0.01 82977 672.86

C7H8 7.82 50029 391303.01 0.01 50029 391.13

CP 4.22 -77288 -326415.54 2.96 -77288 -228388.25

MCP 11.90 -106790 -1270303.26 7.73 -106790 -825326.23

CH 11.52 -123190 -1419169.36 20.32 -123190 -2503582.59

ECP 0.71 -127190 -90891.70 0.71 -127190 -90850.88

MCH 15.26 -154890 -2363156.82 19.25 -154890 -2981292.20

223TMB 0.00 -204890 0.00 1.86 -204890 -380566.37

H2O 0.00 -241814 -0.19 0.00 -241814 0.00

C2Cl4 0.00 -100488 0.00 0.00 -100488 -27.51

HCL 0.00 -100488 0 0.02 -100488 -1629.40 NaOH 0.00 0 0.00 0.00

TOTAL 394.58 -45996357 338.34 -50790738


69

6.1.3 For reactants

Cp of Gas at 25° C to 170° C

Components n

i x

i ∫CpGdT xii∫CpGdT

kmole/hr Mol% kJ/kmole kJ/kmole

H2 72.49

18.37 4214.10 774.1861

C1 9.20

2.33

5746.43 133.9922

C2 5.95

1.51

9020.95 135.9811

C3 3.53

0.90

12889.61 115.3638

n C4 12.26

3.11

16918.74 525.5668

n C 5 58.30

14.78 20860.70 3082.3384

n C 6 46.20

11.71 24834.86 2907.7137

n C7 23.23

5.89

28805.94 1695.7378

i-C4 0.74

0.19

16967.58 31.9710

i C 5 37.52

9.51

20771.74 1974.9472 2 MP 21.8

2 5.53

25105.30 1387.9933 3 MP 14.0

1 3.55

24821.51 881.2673 2,2 DMB 1.6

1 0.41

24901.95 101.8659 2,3DMB 3.5

1 0.89

24640.13 219.2063 2 MH 9.3

2 2.36

29441.95 695.4734 3 MH 9.3

2 2.36

28781.12 679.6809 2,2 DMP 0.6

8 0.17

29355.81 50.9110 2,3 DMP 2.7

9 0.71

-4163.13 -29.4658 2,4 DMP 1.4

2 0.36

28781.12 103.3678 3,3 DMP 0.4

4 0.11

28781.12 32.0539 3 EP 0.7

0 0.18

28781.12 51.0089

C6H6 8.11

2.06

15030.04 309.0205 C7H8 7.8

2 1.98

18801.43 372.6870 CP 4.2

2 1.07

15761.36 168.6997 MCP 11.9

0 3.01

20285.01 611.5245 CH 11.5

2 2.92

19945.76 582.3328 ECP 0.7

1 0.18

24921.30 45.1340 MCH 15.2

6 3.87

24238.46 937.2080 223TMB 0.0

0 0.00

28927.16 0.0000 H2O 0.0

0 0.00

0.00

0.0000 C2Cl4 0.0

0 0.00

0.00

0.0000 HCL 0.0

0 0.00

0 0.0000 NaOH 0.0

0 0.00

0 0.0000 TOTAL 394.58 10

0 18577.77


70

6.1.4 For products

Cp of gas at 25°C to 175°C

Components ni xi ∫CpGdT xii∫CpGdT kmole/hr Mol% kJ/kmole kJ/kmole

H2 16.32 4.82 4360.15 210.336 C1 9.21 2.72 5965.68 162.456 C2 5.98 1.77 9379.74 165.772 C3 3.61 1.07 13407.51 143.216 n C4 6.09 1.80 17592.94 316.917 n C 5 14.08 4.16 21695.55 903.033 n C 6 10.84 3.20 25828.32 827.781 n C7 1.86 0.55 29957.92 164.473 i-C4 6.84 2.02 17647.22 356.964 i C 5 82.93 24.51 21607.06 5296.669 2 MP 35.66 10.54 26111.09 2752.097 3 MP 21.85 6.46 25814.45 1667.445 2,2 DMB 13.62 4.03 25905.34 1042.861 2,3DMB 8.59 2.54 25632.22 650.678 2 MH 15.45 4.57 30627.01 1398.720 3 MH 12.80 3.78 29932.92 1132.194 2,2 DMP 4.17 1.23 30545.77 376.194 2,3 DMP 7.90 2.33 -4377.30 -102.206 2,4 DMP 3.51 1.04 29932.92 310.204 3,3 DMP 2.99 0.88 29932.92 264.824 3 EP 1.16 0.34 29932.92 102.929 C6H6 0.01 0.00 15649.22 0.375 C7H8 0.01 0.00 19568.49 0.452 CP 2.96 0.87 16429.78 143.505 MCP 7.73 2.28 21129.78 482.683 CH 20.32 6.01 20790.13 1248.866 ECP 0.71 0.21 25959.49 54.808 MCH 19.25 5.69 25243.14 1436.140 223TMB 1.86 0.55 30093.11 165.215 H2O 0.00 0.00 0.00 0.000 C2Cl4 0.00 0.00 0.00 0.000 HCL 0.02 0.00 0 0.000 NaOH 0.00 0.00 0 0.000

TOTAL 338.34 100 21675.600


71

6.1.5 Heat of reaction

∆Hrxn = ∆Hprd - ∆Hrea

∆Hprd = ni∆Hf° + nT∫CpGdT

now,

∆Hprd = -50790738 +

∆Hprd = -43457097 kJ/hr

now,

∆Hrea = ni∆Hf° + nT∫CpGdT

∆Hrea = -45996357 + 7330467.333

∆Hrea = -38665890 kJ/hr

SO,


∆Hrxn = -43457097 - -38665890

∆Hrxn = -4791208 kJ/hr

∆Hrxn = -5.E+06 kJ/hr

6.1.6 For cooling coils

Components ni xi ∫CpLdT n∫CpLdT

kmole/hr Mol% kJ/kmole K kJ/hr Water 2900.00 100.00 1510.00 4379000

Total 4379000

Heat Gained By Cooling Water = Heat generated by Reactions

4.379E+06 kJ/hr = -4.791E+06 kJ/hr


72

6.2 ENERGY BALANCE AROUND REACTOR R-102:


73

6.2.1 Molar Composition

Components STREAM IN STREAM OUT

Mol% Mol%

H2 4.8240 4.7884

C1 2.7232 2.7199

C2 1.7673 1.7583

C3 1.0682 1.0440

n C4 1.8014 0.5435

n C 5 4.1623 0.8333

n C 6 3.2049 0.2565

n C7 0.5490 0.0275

i-C4 2.0228 3.2998

i C 5 24.5136 27.8671

2 MP 10.5400 11.4440

3 MP 6.4593 6.9121

2,2 DMB 4.0257 5.3107

2,3DMB 2.5385 2.8607

2 MH 4.5669 4.6026

3 MH 3.7824 3.8835

2,2 DMP 1.2316 1.3202

2,3 DMP 2.3349 2.4736

2,4 DMP 1.0363 1.0809

3,3 DMP 0.8847 0.9402

3 EP 0.3439 0.3715

C6H6 0.0024 0.0000

C7H8 0.0023 0.0000

CP 0.8734 0.8740

MCP 2.2844 2.2857

CH 6.0070 6.0105

ECP 0.2111 0.2113

MCH 5.6892 5.6925

223TMB 0.5490 0.5878

H2O 0.0000 0.0000

C2Cl4 0.0001 0.0001

HCL 0.0048 0.0048 NaOH 0.0000 0.0000


74

6.2.2 Heat of Reaction

Components ∆Hf° Reactants ∆Hf°Products

Heat of formation at 25oC

ni ∆Hf° ni∆Hf° ni ∆Hf° ni∆Hf°

kmole/hr kJ/kmole kJ/hr kmole/hr kJ/kmole kJ/hr H2 16.32 0 0.00 16.20 0 0.00 C1 9.21 -74900 -690056.81 9.20 -74900 -689222.26 C2 5.98 -84738 -506670.71 5.95 -84738 -504081.16 C3 3.61 -103890 -375443.21 3.53 -103890 -366943.86 n C4 6.09 -126190 -769057.96 1.84 -126190 -232045.09 n C 5 14.08 -146490 -2062855.48 2.82 -146490 -412970.40 n C 6 10.84 -167290 -1813915.64 0.87 -167290 -145197.88 n C7 1.86 -187890 -348990.26 0.09 -187890 -17459.69 i-C4 6.84 -134590 -921061.70 11.16 -134590 -1502531.13 i C 5 82.93 -154590 -12820832.96 94.28 -154590 -14574755.94 2 MP 35.66 -174390 -6218533.77 38.72 -174390 -6751921.51 3 MP 21.85 -171690 -3751986.83 23.38 -171690 -4014954.53 2,2 DMB 13.62 -185690 -2529025.09 17.97 -185690 -3336340.09 2,3DMB 8.59 -177890 -1527774.43 9.68 -177890 -1721663.04 2 MH 15.45 -195090 -3014315.96 15.57 -195090 -3037828.49 3 MH 12.80 -192390 -2461966.49 13.14 -192390 -2527762.64 2,2 DMP 4.17 -206290 -859541.38 4.47 -206290 -921385.12 2,3 DMP 7.90 -199390 -1575066.62 8.37 -199390 -1668626.89 2,4 DMP 3.51 -202090 -708549.55 3.66 -202090 -739009.55 3,3 DMP 2.99 -201690 -603699.30 3.18 -201690 -641535.51 3 EP 1.16 -189790 -220794.33 1.26 -189790 -238559.35 C6H6 0.01 82977 672.86 0.00 82977 2.04 C7H8 0.01 50029 391.13 0.00 50029 1.40 CP 2.96 -77288 -228388.25 2.96 -77288 -228521.45 MCP 7.73 -106790 -825326.23 7.73 -106790 -825807.58 CH 20.32 -123190 -2503582.59 20.33 -123190 -2505042.75 ECP 0.71 -127190 -90850.88 0.71 -127190 -90903.86 MCH 19.25 -154890 -2981292.20 19.26 -154890 -2983030.96 223TMB 1.86 -204890 -380566.37 1.99 -204890 -407443.50 H2O 0.00 -241814 0.00 0.00 -241814 0.00 C2Cl4 0.000273748 -100488 -27.51 0.00 -100488 -27.52 HCL 0.016214908 0 0 0.02 0 0.00 NaOH NaOOOH

0 0 0 0.00 0 0.00 TOTAL 338.34 -50789109 338.34 -51085568


75

6.2.3 For Reactants Cp of Gas 25

oC to 120

oC

Components ni xi ∫CpGdT xii∫CpGdT

kmolw/hr Mol% kJ/kmole kJ/kmole H2 16.32 4.82 2755.90 132.95 C1 9.21 2.72 3631.20 98.88 C2 5.98 1.77 5602.91 99.02 C3 3.61 1.07 7969.39 85.13 n C4 6.09 1.80 10499.69 189.14 n C 5 14.08 4.16 12918.82 537.72 n C 6 10.84 3.20 15382.42 493.00 n C7 1.86 0.55 17844.04 97.97 i-C4 6.84 2.02 10504.74 212.49 i C 5 82.93 24.51 12837.25 3146.87 2 MP 35.66 10.54 15538.33 1637.73 3 MP 21.85 6.46 15374.77 993.11 2,2 DMB 13.62 4.03 15375.37 618.96 2,3DMB 8.59 2.54 15219.10 386.34 2 MH 15.45 4.57 18178.23 830.19 3 MH 12.80 3.78 17822.99 674.14 2,2 DMP 4.17 1.23 18070.27 222.55 2,3 DMP 7.90 2.33 -2304.75 -53.81 2,4 DMP 3.51 1.04 17822.99 184.70 3,3 DMP 2.99 0.88 17822.99 157.68 3 EP 1.16 0.34 17822.99 61.29 C6H6 0.01 0.00 9189.32 0.22 C7H8 0.01 0.00 11547.23 0.27 CP 2.96 0.87 9515.48 83.11 MCP 7.73 2.28 12346.59 282.04 CH 20.32 6.01 12055.61 724.18 ECP 0.71 0.21 15166.19 32.02 MCH 19.25 5.69 14782.92 841.03 223TMB 1.86 0.55 17857.25 98.04 H2O 0.00 0.00 0.00 0.00 C2Cl4 0.00 0.00 0.00 0.00 HCL 0.02 0.00 0.00 0.00 NaOH 0.00 0.00 0.00 0.00

TOTAL 338.34 100 369150.25 12866.97


76

6.2.4 For Products Cp of Gas 25

oC to 123

oC

Components ni xi ∫CpGdT xii∫CpGdT

kmolw/hr Mol% kJ/kmole kJ/kmole H2 16.20 4.79 2843.26 136.147 C1 9.20 2.72 3754.15 102.108 C2 5.95 1.76 5799.15 101.967 C3 3.53 1.04 8251.04 86.140 n C4 1.84 0.54 10867.99 59.070 n C 5 2.82 0.83 13374.02 111.441 n C 6 0.87 0.26 15924.28 40.853 n C7 0.09 0.03 18472.49 5.074 i-C4 11.16 3.30 10875.05 358.851 i C 5 94.28 27.87 13291.37 3703.923 2 MP 38.72 11.44 16086.56 1840.947 3 MP 23.38 6.91 15916.28 1100.144 2,2 DMB 17.97 5.31 15920.31 845.485 2,3DMB 9.68 2.86 15758.11 450.789 2 MH 15.57 4.60 18822.99 866.342 3 MH 13.14 3.88 18451.11 716.553 2,2 DMP 4.47 1.32 18714.89 247.072 2,3 DMP 8.37 2.47 -2402.39 -59.425 2,4 DMP 3.66 1.08 18451.11 199.434 3,3 DMP 3.18 0.94 18451.11 173.473 3 EP 1.26 0.37 18451.11 68.552 C6H6 0.00 0.00 9521.25 0.001 C7H8 0.00 0.00 11960.61 0.001 CP 2.96 0.87 9867.22 86.235 MCP 7.73 2.29 12796.14 292.482 CH 20.33 6.01 12500.07 751.319 ECP 0.71 0.21 15718.56 33.206 MCH 19.26 5.69 15319.17 872.051 223TMB 1.99 0.59 18490.44 108.684 H2O 0.00 0.00 0.00 0.000 C2Cl4 0.00 0.00 0.00 0.000 HCL 0.02 0.00 0.00 0.000 NaOH 0.00 0.00 0.00 0.000

TOTAL 338.34 100 13298.917


77

6.2.5 Heat of reaction


∆Hprd

=

ni∆Hf°

+ nT∫CpGdT

now,

∆Hprd = -51085568 + 4499509.04

∆Hprd

=

-46586059.29

kJ/hr

now,

∆Hrea = ni∆Hf° + nT∫CpGdT

∆Hrea

=

-50789109

+

4353361.694

∆Hrea

=

-46435747

kJ/hr

so, ∆Hrxn = ∆Hprd - ∆Hrea

∆Hrxn = -46586059 - -46435747

∆Hrxn = -2.E+05 kJ/hr

6.2.6 For cooling coils

Components ni xi ∫CpGdT n∫CpLdT

kmole/hr Mol% kJ/kmole K kJ/hr Water 95.00 100.00 1510.00 143450

Total 143450

Heat Gained By Cooling Water = Heat generated by Reaction

1.435E+05 kJ/hr = -1.503E+05 kJ/hr


78

6.3 ENERGY BALANCE AROUND HEAT EXCHANGER E 101:

E-101 TUBE SIDE SHELL SIDE

Temperature (0

C) Inlet Temperature 36.84 123

Outlet Temperature 70 93.63

Boiling Point 5.901 44.5039

Pressure (kPa) Inlet Pressure 2400 2200

Outlet Pressure 2370 2100

Average Pressure

vapor Fraction in 0.205 0.0917

vapor Fraction out 0.249 0.0678

vapor Fraction avg 0.227 0.07975

Constant

Heat of Vaporization 78945.18 87741.00 (kJ/kmole)


79

6.3.1 Molar Composition:

Components

Stream No.3 Stream No.4 Stream No.10 Stream No.11

Mol% Mol% Mol% Mol%

H2 18.3713 18.3713 4.7884 4.7884

C1 2.3317 2.3317 2.7199 2.7199

C2 1.5074 1.5074 1.7583 1.7583

C3 0.8950 0.8950 1.0440 1.0440

n C4 3.1064 3.1064 0.5435 0.5435

n C 5 14.7758 14.7758 0.8333 0.8333

n C 6 11.7082 11.7082 0.2565 0.2565

n C7 5.8868 5.8868 0.0275 0.0275

i-C4 0.1884 0.1884 3.2998 3.2998

i C 5 9.5079 9.5079 27.8671 27.8671 2 MP 5.5287 5.5287 11.4440 11.4440 3 MP 3.5504 3.5504 6.9121 6.9121 2,2 DMB 0.4091 0.4091 5.3107 5.3107 2,3DMB 0.8896 0.8896 2.8607 2.8607 2 MH 2.3622 2.3622 4.6026 4.6026 3 MH 2.3616 2.3616 3.8835 3.8835 2,2 DMP 0.1734 0.1734 1.3202 1.3202 2,3 DMP 0.7078 0.7078 2.4736 2.4736 2,4 DMP 0.3592 0.3592 1.0809 1.0809 3,3 DMP 0.1114 0.1114 0.9402 0.9402 3 EP 0.1772 0.1772 0.3715 0.3715

C6H6 2.0560 2.0560 0.0000 0.0000 C7H8 1.9822 1.9822 0.0000 0.0000

CP 1.0703 1.0703 0.8740 0.8740

MCP 3.0147 3.0147 2.2857 2.2857

CH 2.9196 2.9196 6.0105 6.0105

ECP 0.1811 0.1811 0.2113 0.2113

MCH 3.8666 3.8666 5.6925 5.6925 223TMB 0.0000 0.0000 0.5878 0.5878

H2O 0.0000 0.0000 0.0000 0.0000

C2Cl4 0.0000 0.0000 0.0001 0.0001

HCL 0.0000 0.0000 0.0048 0.0048 NaOH 0.0000 0.0000 0.0000 0.0000

Total 100 100 100 100


80

6.3.2 Tube Side

Components ni xi liquid

Fraction ∫CpLdT xii∫CpLdT

kmole/hr Mol% kJ/kmole K kJ/kmole K

H2 72.49 18.37 0.0170 163840.79 2784.06634

C1 9.20 2.33 0.0077 127630.87 988.271101

C2 5.95 1.51 0.0111 7264.71 80.3047805

C3 3.53 0.90 0.0090 4742.84 42.4946293

n C4 12.26 3.11 0.0360 5055.50 182.108916

n C 5 58.30 14.78 0.1810 5890 1065.39389

n C 6 46.20 11.71 0.1469 6853.99 1006.81056

n C7 23.23 5.89 0.0745 7784.82 579.918369

i-C4 0.74 0.19 0.0021 5168.13 10.9664692

i C 5 37.52 9.51 0.1160 5884.95 682.360958

2 MP 21.82 5.53 0.0691 6811.58 470.452231

3 MP 14.01 3.55 0.0444 6688.65 297.186824

2,2 DMB 1.61 0.41 0.0051 6649.77 33.8243427

2,3DMB 3.51 0.89 0.0111 6642.84 73.7434272

2 MH 9.32 2.36 0.0298 7826.38 233.617288

3 MH 9.32 2.36 0.0299 7701.81 230.101309

2,2 DMP 0.68 0.17 0.0022 7802.27 17.0513012

2,3 DMP 2.79 0.71 0.0089 7631.96 68.2607597

2,4 DMP 1.42 0.36 0.0045 7904.69 35.7737834

3,3 DMP 0.44 0.11 0.0014 7552.68 10.6206163

3 EP 0.70 0.18 0.0022 7689.52 17.2390551

C6H6 8.11 2.06 0.0258 4748.36 122.37503

C7H8 7.82 1.98 0.0251 5456.22 137.127268

CP 4.22 1.07 0.0133 4556.56 60.4014987

MCP 11.90 3.01 0.0379 5625.98 213.162185

CH 11.52 2.92 0.0368 5477.83 201.410753

ECP 0.71 0.18 0.0023 6587.94 15.1176227

MCH 15.26 3.87 0.0490 6545.43 320.449969

223TMB 0.00 0.00 0.0000 7490.68 0

H2O 0.00 0.00 0.0000 2496.55 0

C2Cl4 0.00 0.00 0.0000 -5566.74 0

HCL 0.00 0.00 0.0004 0.0000 0

NaOH 0.00 0.00 0.0000 0.0000 0

TOTAL 394.58 100.00 1.00 464434.24 7715.01


81

Components ni xi Vapor

Fraction ∫CpGdT xii∫CpGdT


H2 72.49 18.37 0.7923 960.45 760.9602

C1 9.20 2.33 0.0801 1231.83 98.6947

C2 5.95 1.51 0.0297 1871.97 55.5301

C3 3.53 0.90 0.0088 2651.24 23.4494

n C4 12.26 3.11 0.0130 3505.53 45.4545

n C 5 58.30 14.78 0.0254 4303.76 109.3437

n C 6 46.20 11.71 0.0083 5125.09 42.3745

n C7 23.23 5.89 0.0018 5945.75 10.8981

i-C4 0.74 0.19 0.0010 3498.95 3.4979

i C 5 37.52 9.51 0.0200 4268.77 85.4095

2 MP 21.82 5.53 0.0050 5172.99 25.8335

3 MP 14.01 3.55 0.0029 5122.97 14.9625

2,2 DMB 1.61 0.41 0.0005 5108.03 2.3304

2,3DMB 3.51 0.89 0.0008 5057.87 4.2946

2 MH 9.32 2.36 0.0009 6035.99 5.3863

3 MH 9.32 2.36 0.0009 5936.93 5.0777

2,2 DMP 0.68 0.17 0.0001 5984.00 0.5420

2,3 DMP 2.79 0.71 0.0003 -700.73 -0.1885

2,4 DMP 1.42 0.36 0.0002 5936.93 1.0988

3,3 DMP 0.44 0.11 0.0000 5936.93 0.2739

3 EP 0.70 0.18 0.0001 5936.93 0.3638

C6H6 8.11 2.06 0.0013 3025.39 4.0382

C7H8 7.82 1.98 0.0005 3818.32 1.8633

CP 4.22 1.07 0.0014 3098.21 4.3221

MCP 11.90 3.01 0.0020 4049.71 8.0060

CH 11.52 2.92 0.0016 3930.95 6.2002

ECP 0.71 0.18 0.0000 4973.82 0.2319

MCH 15.26 3.87 0.0012 4857.50 5.6009

223TMB 0.00 0.00 0.0000 5931.16 0.0000

H2O 0.00 0.00 0.0000 0.00 0.0000

C2Cl4 0.00 0.00 0.0000 0.00 0.0000

HCL 0.00 0.00 0.0000 0.00 0.0000

NaOH 0.00 0.00 0.0000 0 0.0000

TOTAL 394.58 100.00 1.00 122577.23 300.97


82

6.3.3 Shell Side




H2 16.20 4.79 0.0126 -199512.06 -2514.64852

C1 9.20 2.72 0.0143 -279046.67 -3994.81536

C2 5.95 1.76 0.0136 -14568.75 -198.505567

C3 3.53 1.04 0.0095 -6659.42 -63.2080384

n C4 1.84 0.54 0.0054 -5626.65 -30.3939262

n C 5 2.82 0.83 0.0087 -5.96E+03 -51.844729

n C 6 0.87 0.26 0.0028 -6894.52 -19.223717

n C7 0.09 0.03 0.0003 -7634.15 -2.48558706

i-C4 11.16 3.30 0.0324 -6170.29 -199.987136

i C 5 94.28 27.87 0.2898 -6036.68 -1749.62666

2 MP 38.72 11.44 0.1221 -6805.47 -830.901233

3 MP 23.38 6.91 0.0739 -6650.91 -491.458483

2,2 DMB 17.97 5.31 0.0564 -6632.83 -373.849325

2,3DMB 9.68 2.86 0.0305 -6613.38 -201.695991

2 MH 15.57 4.60 0.0498 -7801.45 -388.551913

3 MH 13.14 3.88 0.0420 -7632.19 -320.811117

2,2 DMP 4.47 1.32 0.0142 -7800.55 -111.039608

2,3 DMP 8.37 2.47 0.0267 -7551.44 -201.977523

2,4 DMP 3.66 1.08 0.0116 -7890.58 -91.9132828

3,3 DMP 3.18 0.94 0.0102 -7563.20 -76.915539

3 EP 1.26 0.37 0.0040 -7595.10 -30.4626677

C6H6 0.00 0.00 0.0000 -4675.81 0

C7H8 0.00 0.00 0.0000 -5385.02 0

CP 2.96 0.87 0.0092 -4701.57 -43.2365038

MCP 7.73 2.29 0.0246 -5691.74 -139.988369

CH 20.33 6.01 0.0648 -5623.11 -364.213341

ECP 0.71 0.21 0.0023 -6637.69 -15.1551398

MCH 19.26 5.69 0.0618 -6628.75 -409.653369

223TMB 1.99 0.59 0.0064 -7355.24 -46.8487831

H2O 0.00 0.00 0.0000 -2241.28 0

C2Cl4 0.00 0.00 0.0000 -5566.74 0

HCL 0.02 0.00 0.0004 0.0000 0 NaOH 0.00 0.00 0.0000 0.0000 0

TOTAL 338.33 100.00 1.00 -673158.11 -11929.58


83




H2 16.20 4.79 0.3974 -768.02 -305.229

C1 9.20 2.72 0.1548 -1060.10 -164.112

C2 5.95 1.76 0.0570 -1676.96 -95.562

C3 3.53 1.04 0.0194 -2401.60 -46.630

n C4 1.84 0.54 0.0054 -3146.11 -16.970

n C 5 2.82 0.83 0.0044 -3884.61 -17.250

n C 6 0.87 0.26 0.0007 -4624.54 -3.431

n C7 0.09 0.03 0.0000 -5363.89 -0.254

i-C4 11.16 3.30 0.0389 -3159.54 -122.906

i C 5 94.28 27.87 0.1691 -3871.29 -654.638

2 MP 38.72 11.44 0.0385 -4677.25 -180.028

3 MP 23.38 6.91 0.0218 -4621.61 -100.737

2,2 DMB 17.97 5.31 0.0209 -4643.51 -97.089

2,3DMB 9.68 2.86 0.0099 -4593.80 -45.345

2 MH 15.57 4.60 0.0084 -5494.82 -46.326

3 MH 13.14 3.88 0.0069 -5360.15 -36.822

2,2 DMP 4.47 1.32 0.0030 -5485.32 -16.370

2,3 DMP 8.37 2.47 0.0045 788.53 3.541

2,4 DMP 3.66 1.08 0.0024 -5360.15 -12.992

3,3 DMP 3.18 0.94 0.0018 -5360.15 -9.652

3 EP 1.26 0.37 0.0006 -5360.15 -3.382

C6H6 0.00 0.00 0.0000 -2814.73 0.000

C7H8 0.00 0.00 0.0000 -3513.06 0.000

CP 2.96 0.87 0.0038 -2964.10 -11.284

MCP 7.73 2.29 0.0062 -3803.45 -23.468

CH 20.33 6.01 0.0140 -3747.10 -52.430

ECP 0.71 0.21 0.0003 -4673.08 -1.360

MCH 19.26 5.69 0.0085 -4541.58 -38.697

223TMB 1.99 0.59 0.0013 -5395.11 -6.827

H2O 0.00 0.00 0.0000 0.00 0.000

C2Cl4 0.00 0.00 0.0000 0.00 0.000

HCL 0.02 0.00 0.0000 0 0.000 NaOH 0.00 0.00 0.0000 0 0.000

TOTAL 338.33 1.00 -167.974


84

6.3.4 Calculations:

TUBE SIDE

Total Enthalpy = Sensible Heat of Liquid + Latent Heat + Sensible Heat of Vapor

HT = HL + HV + HG

HG = n∫CpGdT

HG = 118755.937 kJ/hr

HV = n λ

HV = 1370608.32 kJ/hr

HL = n∫CpLdT

HL = 3044189.64 kJ/hr

HT = 4533553.9 kJ/hr

HT = 4.53E+06 kJ/hr

SHELL SIDE Total Enthalpy = Sensible Heat of Liquid + Latent Heat + Sensible Heat of Vapor

HT = HL + HV + HG

HG = n∫CpGdT

HG = -56830.9023 kJ/hr

HV = n λ

HV = -709486.596 kJ/hr

HL = n∫CpLd

HL = -4036164.38 kJ/hr HT

=

-4802481.88 kJ/hr

HT = -4.80E+06 kJ/hr

Heat Gained By Tube Side = Heat Lost By Shell Side

4.534E+06 kJ/hr = -4.802E+06 kJ/hr


85

6.4 ENERGY BALANCE AROUND HEAT EXCHANGER E 102:

E-102 TUBE SIDE SHELL SIDE

Temperature (0

C) Inlet Temperature 70 175

Outlet Temperature 147 120

Boiling Point 5.901 30.43

Pressure (kPa) Inlet Pressure 2370 2269

Outlet Pressure 2330 2210

Average Pressure

vapor Fraction in 0.2146 0.3641

vapor Fraction out 0.3489 8.61E-02 vapor Fraction avg 0.28175 0.2251

Boiling Point 5.901 30.43 Constant

Heat of Vaporization 10589.08 -23473.32

(kJ/kmole)


86

6.4.1 Molar Composition:

Components Stream No.3 Stream No.4 Stream No.10 Stream No.11

Mol% Mol% Mol% Mol%

H2 18.3713 18.3713 4.8240 4.8240

C1 2.3317 2.3317 2.7232 2.7232

C2 1.5074 1.5074 1.7673 1.7673

C3 0.8950 0.8950 1.0682 1.0682

n C4 3.1064 3.1064 1.8014 1.8014

n C 5 14.7758 14.7758 4.1623 4.1623

n C 6 11.7082 11.7082 3.2049 3.2049

n C7 5.8868 5.8868 0.5490 0.5490

i-C4 0.1884 0.1884 2.0228 2.0228

i C 5 9.5079 9.5079 24.5136 24.5136 2 MP 5.5287 5.5287 10.5400 10.5400 3 MP 3.5504 3.5504 6.4593 6.4593 2,2 DMB 0.4091 0.4091 4.0257 4.0257 2,3DMB 0.8896 0.8896 2.5385 2.5385 2 MH 2.3622 2.3622 4.5669 4.5669 3 MH 2.3616 2.3616 3.7824 3.7824 2,2 DMP 0.1734 0.1734 1.2316 1.2316 2,3 DMP 0.7078 0.7078 2.3349 2.3349 2,4 DMP 0.3592 0.3592 1.0363 1.0363 3,3 DMP 0.1114 0.1114 0.8847 0.8847 3 EP 0.1772 0.1772 0.3439 0.3439

C6H6 2.0560 2.0560 0.0024 0.0024 C7H8 1.9822 1.9822 0.0023 0.0023 CP 1.0703 1.0703 0.8734 0.8734 MCP 3.0147 3.0147 2.2844 2.2844 CH 2.9196 2.9196 6.0070 6.0070 ECP 0.1811 0.1811 0.2111 0.2111 MCH 3.8666 3.8666 5.6892 5.6892 223TMB 0.0000 0.0000 0.5490 0.5490 H2O 0.0000 0.0000 0.0000 0.0000 C2Cl4 0.0000 0.0000 0.0001 0.0001 HCL 0.0000 0.0000 0.0048 0.0048 NaOH 0.0000 0.0000 0.0000 0.0000

Total 100 100 100 100


87

6.4.2 Tube Side



kmole/hr Mol% kJ/kmole K kJ/kmole K H2 72.49 18.37 0.0170 524673.28 8915.51612 C1 9.20 2.33 0.0077 758742.22 5875.091135 C2 5.95 1.51 0.0111 39811.05 440.075118 C3 3.53 0.90 0.0090 17954.99 160.8721251 n C4 12.26 3.11 0.0360 15009.50 540.6714188 n C 5 58.30 14.78 0.1810 1.57E+04 2835.3435 n C 6 46.20 11.71 0.1469 18107.01 2659.813793 n C7 23.23 5.89 0.0745 20036.58 1492.595104 i-C4 0.74 0.19 0.0021 16529.78 35.07521004 i C 5 37.52 9.51 0.1160 15866.01 1839.666534 2 MP 21.82 5.53 0.0691 17855.82 1233.239608 3 MP 14.01 3.55 0.0444 17448.62 775.2681686 2,2 DMB 1.61 0.41 0.0051 17398.60 88.49878246 2,3DMB 3.51 0.89 0.0111 17347.93 192.5827109 2 MH 9.32 2.36 0.0298 20470.78 611.0525945 3 MH 9.32 2.36 0.0299 20020.43 598.1359298 2,2 DMP 0.68 0.17 0.0022 20459.10 44.7119097 2,3 DMP 2.79 0.71 0.0089 19805.23 177.1392678 2,4 DMP 1.42 0.36 0.0045 20693.98 93.6535025 3,3 DMP 0.44 0.11 0.0014 19844.47 27.90540672 3 EP 0.70 0.18 0.0022 19919.07 44.65634249 C6H6 8.11 2.06 0.0258 12272.22 316.2807209 C7H8 7.82 1.98 0.0251 14132.02 355.1701859 CP 4.22 1.07 0.0133 12335.95 163.5246758 MCP 11.90 3.01 0.0379 14925.56 565.5136593 CH 11.52 2.92 0.0368 14827.71 545.1904029 ECP 0.71 0.18 0.0023 17405.47 39.94105385 MCH 15.26 3.87 0.0490 17395.98 851.6697922 223TMB 0.00 0.00 0.0000 19272.40 0 H2O 0.00 0.00 0.0000 5875.66 0 C2Cl4 0.00 0.00 0.0000 -5566.74 0 HCL 0.00 0.00 0.0004 0.0000 0 NaOH 0.00 0.00 0.0000 0.0000 0

TOTAL 394.58 100.00 1.00 1776537.03 22638.42


88




H2 72.49 18.37 0.7923 2240.16 1774.8758

C1 9.20 2.33 0.0801 3099.31 248.3173

C2 5.95 1.51 0.0297 4906.03 145.5322

C3 3.53 0.90 0.0088 7026.70 62.1490

n C4 12.26 3.11 0.0130 9204.49 119.3501

n C 5 58.30 14.78 0.0254 11364.60 288.7354

n C 6 46.20 11.71 0.0083 13529.06 111.8589

n C7 23.23 5.89 0.0018 15691.84 28.7620

i-C4 0.74 0.19 0.0010 9243.86 9.2411

i C 5 37.52 9.51 0.0200 11326.69 226.6241 2 MP 21.82 5.53 0.0050 13683.03 68.3319 3 MP 14.01 3.55 0.0029 13520.74 39.4895 2,2 DMB 1.61 0.41 0.0005 13586.11 6.1982 2,3DMB 3.51 0.89 0.0008 13440.61 11.4123 2 MH 9.32 2.36 0.0009 16073.41 14.3433 3 MH 9.32 2.36 0.0009 15681.00 13.4115 2,2 DMP 0.68 0.17 0.0001 16047.89 1.4536 2,3 DMP 2.79 0.71 0.0003 -2332.94 -0.6275 2,4 DMP 1.42 0.36 0.0002 15681.00 2.9021 3,3 DMP 0.44 0.11 0.0000 15681.00 0.7234 3 EP 0.70 0.18 0.0001 15681.00 0.9608

C6H6 8.11 2.06 0.0013 8238.34 10.9963 C7H8 7.82 1.98 0.0005 10281.35 5.0173 CP 4.22 1.07 0.0014 8682.12 12.1120 MCP 11.90 3.01 0.0020 11136.05 22.0152 CH 11.52 2.92 0.0016 10976.71 17.3133 ECP 0.71 0.18 0.0000 13682.27 0.6378 MCH 15.26 3.87 0.0012 13295.61 15.3305 223TMB 0.00 0.00 0.0000 15784.86 0.0000 H2O 0.00 0.00 0.0000 0.00 0.0000 C2Cl4 0.00 0.00 0.0000 0.00 0.0000 HCL 0.00 0.00 0.0000 0.00 0.0000 NaOH 0.00 0.00 0.0000 0 0.0000

TOTAL 394.58 100.00 1.00 326452.92 917.79


89

6.4.3 Shell Side




H2 16.32 4.82 0.0075 -456122.95 -3408.41681

C1 9.21 2.72 0.0077 -909163.18 -7029.54256

C2 5.98 1.77 0.0082 -48009.05 -391.363277

C3 3.61 1.07 0.0067 -18809.95 -126.759605

n C4 6.09 1.80 0.0147 -13693.05 -201.275326

n C 5 14.08 4.16 0.0411 -1.24E+04 -508.97138

n C 6 10.84 3.20 0.0364 -14260.24 -518.854674

n C7 1.86 0.55 0.0069 -15486.31 -106.757685

i-C4 6.84 2.02 0.0156 -15880.13 -246.956911

i C 5 82.93 24.51 0.2348 -12690.75 -2980.16715

2 MP 35.66 10.54 0.1162 -13913.02 -1616.61507

3 MP 21.85 6.46 0.0722 -13550.51 -977.749908

2,2 DMB 13.62 4.03 0.0429 -13520.48 -580.567259

2,3DMB 8.59 2.54 0.0279 -13468.91 -376.203287

2 MH 15.45 4.57 0.0560 -15940.33 -892.872845

3 MH 12.80 3.78 0.0466 -15503.51 -722.528748

2,2 DMP 4.17 1.23 0.0146 -15904.92 -232.571117

2,3 DMP 7.90 2.33 0.0287 -15304.59 -438.49287

2,4 DMP 3.51 1.04 0.0124 -16066.59 -198.80811

3,3 DMP 2.99 0.88 0.0107 -15485.36 -166.463623

3 EP 1.16 0.34 0.0042 -15373.62 -64.8511144

C6H6 0.01 0.00 0.0000 -9508.10 0

C7H8 0.01 0.00 0.0000 -10953.97 0

CP 2.95 0.87 0.0091 -9784.23 -88.6629931

MCP 7.73 2.28 0.0263 -11667.38 -306.572716

CH 20.32 6.01 0.0712 -12119.17 -863.057646

ECP 0.71 0.21 0.0027 -13571.47 -36.3929815

MCH 19.25 5.69 0.0722 -13677.27 -987.079201

223TMB 1.86 0.55 0.0066 -14725.77 -97.3980337

H2O 0.00 0.00 0.0000 -4268.44 0

C2Cl4 0.00 0.00 0.0000 -5566.74 0

HCL 0.02 0.00 0.0004 0.0000 0

NaOH 0.00 0.00 0.0000 0.0000 0

TOTAL 338.33 100.00 1.00 -1786381.51 -18726.20


90



kmolw/hr Mol% kJ/kmole K kJ/kmole K

H2 16.32 4.82 0.1194 -1604.25 -77.390

C1 9.21 2.72 0.0612 -2334.47 -63.572

C2 5.98 1.77 0.0344 -3776.83 -66.749

C3 3.61 1.07 0.0176 -5438.13 -58.089

n C4 6.09 1.80 0.0238 -7093.26 -127.777

n C 5 14.08 4.16 0.0426 -8776.73 -365.314

n C 6 10.84 3.20 0.0244 -10445.90 -334.784

n C7 1.86 0.55 0.0031 -12113.88 -66.507

i-C4 6.84 2.02 0.0283 -7142.48 -144.477

i C 5 82.93 24.51 0.2632 -8769.80 -2149.795

2 MP 35.66 10.54 0.0866 -10572.76 -1114.364

3 MP 21.85 6.46 0.0515 -10439.68 -674.335

2,2 DMB 13.62 4.03 0.0357 -10529.97 -423.901

2,3DMB 8.59 2.54 0.0210 -10413.12 -264.339

2 MH 15.45 4.57 0.0277 -12448.77 -568.529

3 MH 12.80 3.78 0.0225 -12109.92 -458.050

2,2 DMP 4.17 1.23 0.0083 -12475.50 -153.645

2,3 DMP 7.90 2.33 0.0140 2072.56 48.392

2,4 DMP 3.51 1.04 0.0070 -12109.92 -125.499

3,3 DMP 2.99 0.88 0.0054 -12109.92 -107.140

3 EP 1.16 0.34 0.0020 -12109.92 -41.642

C6H6 0.01 0.00 0.0000 -6459.90 -0.155

C7H8 0.01 0.00 0.0000 -8021.26 -0.185

CP 2.95 0.87 0.0081 -6914.30 -60.392

MCP 7.73 2.28 0.0167 -8783.19 -200.641

CH 20.32 6.01 0.0407 -8734.52 -524.684

ECP 0.71 0.21 0.0011 -10793.30 -22.788

MCH 19.25 5.69 0.0303 -10460.21 -595.106

223TMB 1.86 0.55 0.0036 -12235.86 -67.176

H2O 0.00 0.00 0.0000 0.00 0.000

C2Cl4 0.00 0.00 0.0000 0.00 0.000

HCL 0.02 0.00 0.0000 0 0.000

NaOH 0.00 0.00 0.0000 0.000

TOTAL 338.33 100.00 1.00 -1982.823


91

6.4.4 Calculations:

TUBE SIDE

Total Enthalpy = Sensible Heat of Liquid + Latent Heat + Sensible Heat of Vapor

HT = HL + HV + HG

HG = n∫CpGdT

HG = 362142.117 kJ/hr

HV = n λ

HV = 4178240.08 kJ/hr

HL = n∫CpLdT

HL = 8932666.754 kJ/hr

HT = 13473048.95 kJ/hr

HT = 1.35E+07 kJ/hr

SHELL SIDE Total Enthalpy = Sensible Heat of Liquid + Latent Heat + Sensible Heat of Vapor

HT = HL + HV + HG

HG = n∫CpGdT

HG = -670852.8413 kJ/hr

HV = n λ

HV = -7941779.131 kJ/hr

HL = n∫CpLd

HL = -6335675.669 kJ/hr HT

=

-14948307.64 kJ/hr

HT = -1.49E+07 kJ/hr

Heat Gained By Tube Side = Heat Lost By Shell Side

1.347E+07 kJ/hr = -1.495E+07 kJ/hr


92

6.5 ENERGY BALANCE AROUND STABILIZER T-101

Energy balance around the stabilizer has been performed following the mass balance.

The reboiler duty and the condenser duties are calculated and the results are verified.

Heat in + Heat generated = Heat out + Heat consumed

Since there is no heat generation and consumption, therefore,

Heat in = Heat out.

The enthalpy of the feed entering (Hin) the column from reference temperature

Tr = 120oC

Hin = 0

The distillate temperature is Td = 115oC

The bottom‘s temperature is Tb = 125oC


93

The enthalpy of the distillate from reference temperature of 120oC is

Hd = -308 kW

The enthalpy of bottom product is

Hb = 96 kW

The reboiler duty can be calculated as

Qreb = V x λ

Qreb = 260 kW

The saturated steam flow rate for reboiling at 1 bar is

ms= Qreb/hs

ms =0.13 kg/s

The cooling duty of the condenser is

Qcon = (L+D) x Cp x (Tavg – Td)

Qcon = 50 kW

The flow rate of cooling water available at 40 oC

mc = Qcon/ (Cp) (Tavg – Td)

mc = 2.38 kg/s

CHAPTER 7

PLANT DESIGN CALCULATIONS

Chapter 7 Plant Design Calculations

94

CHAPTER # 7

PLANT DESIGN CALCULATIONS

7.1 REACTOR

Types of Reactors The most common types of Reactors are

1. Fixed bed Reactor

2. Fluidized bed Rector

3. Stirrer tank Reactor

Fixed bed reactor can be further classified on the biases of either heat is supplied

during reaction or not.

i. Adiabatic

ii. Non adiabatic

The reactions taking place within the reactor may be in gas phase or there might a

case of trickle operation. For gas phase reactions some important reactor

configurations are as under.

1. Single adiabatic bed

2. Radial flow

3. Adiabatic beds in series with intermediate cooling or heating

4. Direct-fired non-adiabatic

Except reactor type and configuration some other factors are important like ,

Distribution system and Sporting ceramic balls which also serves for uniform

distribution of flow as well. Our Reactor in this case is non-isothermal adiabatic

reactor with basket type distribution system and standard ceramic balls installation.

Detailed calculations of distribution system is given in design calculations.


95

7.2 ALGORITHM FOR DETERMINING REACTION MECHANISM AND

RATE-LIMITING STEP:

Adsorption

Surface Reaction

Desorption

Assume surface reaction is

rate limiting

If the surface reaction is

limiting then:

Site balance:

Substituting for CN-S, CI-S, and CV into CT = CV (1 + KN PN + KI PI) :


96

where KP is the thermodynamic equilibrium constant for the reactor.

Linearizing the Initial Rate:


97

Reactor R-101 Design

Reaction n-Butane n-Pentane n-Hexane n-Heptane

K 8.5 7.9 6.7 5.5

KN 1.12 1.2 1.6 1.75

KI 13 11 9 8

Pressure P 2300 kPa

Temperature T 443 K

Compressibility Factor Z 0.8392

Universal Gas Constant R 8.314 kPa/kmol K

Molar Flow rate Fo 394.58 kmol/hr

Volume Flow Rate 530.26 m3/hr

Overall Concentration 744.13 mol/dm3 Stream 7

Components

Mole Fraction Molar Flow

Rate Volumetric Flow Fao

Concentration CAo

Conversion X

n-Butane 0.0309 12.19 16.38 22.9936 0.5 n-Pentane 0.1476 58.25 78.27 109.8335 0.75

n-Hexane 0.117 46.18 62.04 87.0632 0.765 n-Heptane 0.0588 23.22 31.18 43.7548 0.919

WB 209.9 kg WH 281.823 kg

WP

357.159

kg

WHe

330.038

kg

WT

1178.92

kg

V Weight of catalyst x 1.6 packing density

1.6 is a designing factor for catalytic Reactor

V 2.3727 m3


98

PRESSURE DROP IN REACTOR R-101

Using ERGUN equation for the pressure drop in packed bed reactors

For the given reactor Length to dia Ratio L/D 5.000 Diameter D 0.845 m 2.773 ft Length L 4.227 m 13.864 ft

Area A 0.561 m2 6.039 ft2

Volume V 2.373 m3 83.726 ft3

For Feed of R-101

Density ρ 73.560 kg/m3 4.586 lb/ft3

Molecular Mass M 65.410

Inlet Molar Flow Rate Fo 394.580 kmol/h 109.606 mol/s

Outlet Molar Flow Rate F 338.3 kmol/h 93.972 mol/s

Pressure P 2300.000 kPa 48049.741 lbf/ft2

Temperature T 170.000 C 443.000 K

Viscosity μ 8.320E-06 lb/ft s


Mass Flux G 12.772 kg/m2 s 2.612 lb/ft2

s

βo 475.371 α 0.000

dy/dw 1.12451E-05 1/y

y

0.986664298

Pressure at outlet P 2269.327886 kPa Pressure Drop ∆P

30.672

kPa


99

Reactor R-102 Design

Reaction n-Butane n-Pentane n-Hexane n-Heptane

K 8.5 7.9 6.7 5.5 KN 1.12 1.2 1.6 1.75 KI 13 11 9 8

Pressure P 2210 kPa

Temperature T 393 K


Universal Gas Constant R 8.314 kPa/kmol K

Molar Flow rate Fo 338.32 kmol/hr

Volume Flow Rate 490.59 m3/hr

Overall Concentration 689.62 mol/dm3 Stream 9

Components

Mole Fraction Molar Flow

Rate Volumetric Flow Fao

Concentration CAo

Conversion X

n-Butane 0.0180 6.09 8.84 12.4227 0.4201 n-Pentane 0.0416 14.08 20.42 28.7040 0.7183 n-Hexane 0.0320 10.84 15.72 22.1019 0.7263 n-Heptane 0.0055 1.86 2.69 3.7861 0.9067

WB 391.619 kg WH 937.904 kg

WP

920.785

kg

WHe

1547.613

kg

WT

3797.921

kg

V Weight of catalyst x 1.6 packing density

1.6 is a designing factor for catalytic Reactor

V 7.64 m3


100

PRESSURE DROP IN REACTOR R-102

Using ERGUN equation for the pressure drop in packed bed reactors

For the given reactor Length to dia Ratio L/D 5.000 Diameter D 1.249 m 4.095 ft Length L 6.243 m 20.476 ft Area A 1.224 m2 13.173 ft2

Volume V 7.644 m3 269.724 ft3

For Feed of R-101

Density ρ 27.340 kg/m

3 1.705 lb/ft3

Molecular Mass M 73.950

Inlet Molar Flow Rate Fo 338.320 kmol/h 93.978 mol/s

Outlet Molar Flow Rate F 338.3 kmol/h 93.972 mol/s

Pressure P 2210.000 kPa

46169.534 lbf/ft2

Temperature T 120.000 C 393.000 K

Viscosity μ 7.160E-06 lb/ft s


Mass Flux G 5.676 kg/m2 s 1.161 lb/ft2

s

βo 262.053 α 0.000

dy/dw 3.44951E-06 1/y

y

0.995928192

Pressure at outlet P 2201.001304 kPa Pressure Drop ∆P

8.999

kPa


101

7.3 DESIGNING OF NAPHTHA FEED PUMP:

A pump is one of the most important pieces of mechanical equipment that is present

in industrial processes. A pump moves liquid from one area to another by increasing

the pressure of the liquid above the amount needed to overcome the combined effects

of friction, gravity and system operating pressures.

There are two types of pump which are generally used in industrial processes: positive

displacement pump and centrifugal. It is important to choose the suitable type of

pump based on process requirement and fluid process properties.

In designing the pump, the knowledge of the effect of parameters; such as pump

capacity, NPSH, pumping maximum temperature, specific gravity, fluid viscosity,

fluid solid content, and the other process requirements are very important. All of these

parameters will affect the selection and design of the pump which will affect the

performance of the pump in the process.

NPSH as a measure to prevent liquid vaporization or called cavitation of pump. Net

Positive Suction Head (NPSH) is the total head at the suction flange of the pump less

the vapor pressure converted to fluid column height of the liquid.

Naphtha feed is coming from the atmospheric distillation column is treated with

hydrogen and brought to a pressure about 4 bar. This stream is then raised to a

pressure of 24 bar using a centrifugal compressor. The design of pump is carried out

using energy balance (extended Bernoulli‘s equation) and the power of the pump is

calculated.


102

The stream at the inlet of the pump is at given conditions and rates specified.

Inlet pressure P1

4 bar

Outlet pressure P2

24 bar

Temperature T

35 °C

Density ρ

664.8 Kg/m3

Viscosity μ

1.037 Kg/m hr

Mass flow rate m

25000 Kg/hr

Molar flowrate F

301 Kmol/hr

Volumetric flowrate Q

37.605 m3/hr

Vapour pressure Pv

69.6 kPa

The optimum diameter of the pipe is found against given flow rate using the graph

Dopt

= 0.1061 m

The velocity of the fluid through the pump is given by

V = 4 X Q

(m/s) πD

2

V = 1.289 m/s

The work done per unit mass is given by the extended Bernoulli‘s equation.

∆W = (∆P/ ρ) + (∆PF/ ρ) + (∆V/2g) (J/kg)

∆W= (2000000/664.8) + (∆PF/664.8) + (0)

The pressure drop due to the friction is given by the Darcy‘s equation

∆PF = 8 x f x L x V2 x ρ

2 x D

For relative roughness (є) =0.046 m

Friction factor (f) = 0.002

An assumed length of 100 m from pump outlet to the inlet of the reactor

∆PF = 8670 N/m2

hence the work done per unit mass is


103

∆W =2419.82 N/m2

The total work is given by taking efficiency of pump (η)=0.7

W = (∆W x m)/ η

W = 2419.82 x 25000/ (3600 x 0.7)

W = 24 KW or 32 hp

The Net positive suction head of the pump can be found by using the formula

NPSHavail = (P1/ρg) – (ΔPf/ρg) – (Pv/ρg)

NPSHavail = 49.37 m


104

7.4 HEAT EXCHANGER DESIGN:

Heat exchanger E-101 is installed to recover the heat of the effluent from reactor R-

101 and heat the naphtha feed to bring it to the required temperature. The hot stream

which is coming from R-101 is at a temperature of 1750C and the cold stream is the

preheated naphtha feed coming from E-101 and is at a temperature of 78.21. The hot

stream is cooled to 1200C which is the required inlet temperature for R-102. Hence

the outlet temperature of naphtha feed can be determined.

The physical properties of both the streams are found at their mean temperatures. The

first iteration is done by assuming a constant specific heat; this is used to find the final

temperature of the naphtha stream to be 1120C.

Cold stream (Naphtha feed)

Inlet temperature (t1) = 78.21 0C

Outlet temperature (t2) = 120 0C

Molar flow rate (n) = 338.316 kmol/hr

Molecular mass (M) = 67

Specific heat (Cp) = 161.75 kJ/kg. k

Viscosity (µ) = 1.50E-5 Ns/m2

Density (ρ) = 112.36 kg/m3

Conductivity (k) = 0.091205 W/m k

Hot stream (effluent R-101)

Inlet temperature (T1) = 175 0C

Outlet temperature (T2) = 120 0C

Molar flow rate (n) = 394.58 kmol/hr

Molecular mass (M) = 74

Specific heat (Cp) = 162.4 kJ/kg. k

Viscosity (µ) = 1.01E-05 Ns/m2

Density (ρ) = 12.75 kg/m3

Conductivity (k) = 2.86E-02 W/m k


105

Tubes of BWG 14 are selected the specifications are

Outer diameter (do) = 0.016 m

Inner diameter (di) = 0.0117836 m

Tube thickness (t) = 0.0021082 m

Tube length (L) = 5 m

The true temperature is found by

∆T = F x ∆Tm

∆Tm = (T2-t1)-(T1-t2)

Ln (T2-t1/T1-t2)

∆Tm = 51.671510020C

F can be found by using graph for two tube passes and one shell pass

F= 0.88

∆T = 0.88 x 51.671510020C

∆T = 45.47oC

The heat transfer area is given by

Q = 2.6 E+6 KJ/hr

A =

Q

U x ∆T

Assume U= 1000 KJ/m2 k

A = 52.78 m2

Number of tubes = A

π x I.D x L

Number of tubes (Nt) = 210

Number of tubes per pass (Np) = 105

Bundle diameter = do x ( Nt/k )1/n


106

For two tube passes k= 0.249 and n=2.207

Bundle diameter (Db) = 0.3388 m

From graph at given bundle diameter clearance =0.0133 m

Shell diameter (Ds) = bundle diameter +shell clearance

Shell diameter = 0.3522 m

For tube pitches of 1.25 do

Number of baffles (b) = 5

Baffle spacing (lb) = L/number of baffles

Baffle spacing = 0.0705 m

Flow area at shell side (As) = (0.25 x di x lb x tubes at central plane)

Tubes at central plane = bundle diameter/ tube pitch

Tubes at central plane = 17

Hence,

Shell flow area = 0.00477 m2

The equivalent diameter of shell (de) = 4 x hydraulic radius

The equivalent diameter of shell = .02565 m

The tube side and shell side velocities can be found by using formula

Velocity = mass flow/ (density x area)

Us = 0.031733114 m/s

Ut = 5.707451295 m/s

Finding tube side heat transfer co=efficient

hi = (k/do)(jh x Re x Pr0.33

)

Reynolds number (Re) = (ρ x di x Ut)/ µ

Prandalt‘s number (Pr) = (Cp xµ)/k

Re = 500000

Pr=0.02664

hi = 2707.3


107

Finding shell side heat transfer co=efficient

ho = (k/de)(jh x Re x Pr0.33

)

Re = 3700000

Pr = 0.057

ho = 2811.45

Overall heat transfer coefficient

U = (1/hi) +(1/ho) (di/do) + (t x di)/(kt x dw)

dw = (di +do)/2

kt= 15 W/m k

U = 981 KJ/m2 k

Pressure drop at tube side

Pt= Np ((8 x jf (L/d) +2.5)x(ρ x Ut))/2

Pt=1000 Pa

Shell side pressure drop

Ps= 8 x Jf x (Ds/de) x (L/lb) x (ρUs2/2)

Ps=440 Pa


108

7.5 DESIGNING OF STABILIZER T-101:

The naphtha stabilizer column is designed as a distillation column. The feed is the

stream coming from the heat exchanger E-102. The stream temperature is 120oC and a

pressure of 18.5 bara. The feed of the column is fractionated and the product are

obtained as specified in the figure.

The method used for design is HENGTEBECK‘S METHOD, it is a modification to

the binary MC‘CABE AND THIELE method for binary distillation. The key

components selected are butane (iso and normal) and iso pentane. The heavier key is

iso-pentane and lighter key is butane stream.

KEYS

FEED FLOW

RATE

(F)

DISTILLATE

FLOW RATE

(D)

BOTTOMS

FOW RATE

(B)

Butane (LK) 12.996 12.9013 0.0946

ISO PENTANE

(HK) 94.234 0.9420 93.292


109

COMPOSITIONS:

The molar fractions of butane and isopentane according to HENGTEBECK‘S

METHOD in the streams are given as

Feed distillate bottoms

Butane 0.12 0.9315 0.001

Iso pentane 0.88 0.0685 0.999

Using Antoine equation at column average temperature the saturation pressure of the

key components is found to be

Psatbutane= 15810 mm Hg

Psatiso pentane= 1480 mm Hg

Relative volatility of the stream with respect of the heavier key

αavg= 10.68

The expression for the vapor liquid equilibrium relation is given as

y= αx

1+(α-1)x

Using this data and developing a table for liquid vapour equilibrium curve

Liquid fraction Vapor fraction

0 0

0.1 0.546

0.2 0.7275

0.3 0.8206

0.4 0.8769

0.5 0.9143

0.6 0.9412

0.7 0.9614

0.8 0.9771

0.9 0.9897

1.0 1.0

Using MC‘CABE AND THIELE method for pseudo binary distillation for

Reflux ratio=5

Feed at bubble point=120oC feed line is vertical


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Intercept of top operating line= (xd)/(R+1)

Intercept of top operating line= 0.155

Number of ideal plates= 7

Feed plate= 5th

Efficiency of column

According to O‘CORNELL‘S equation, the overall efficiency of the column can be

estimated by the relation

Eo= 51-32.5log(µavgαavg )

µavg=(0.12x0.104)+(0.88x0.104)

µavg=0.104 mNs/m2

Using given equation the overall efficiency of the column is found to be EO=45%

Actual number of plates = 14

Column diameter calculations

The diameter of the column is calculated by using the formula for vapor flow through

a cylinder

Diameter of column = (4 x molar flow of vapors x mol.massavg)

1/2

(ρg x V‘x π)1/2

For bottom of the column

Mavg= 84.32

Molar flow rate = (R+1) D

Molar flow rate = 292.5 kmol/hr

ρg = 47.44kg/m3 using general gas equation

ρl = 550 kg/m3

V‘= K (ρl/ ρg -1)1/2

K can be found for 18 inches (460mm) tray spacing to be 0.135

V‘=0.437m/s

Diabottom = 0.65m (2.13 ft)


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For top of the column

Mavg= 76

Molar flow rate = (R+1) D

Molar flow rate = 292.5 kmol/hr

ρg = 44kg/m3 using general gas equation

ρl = 480kg/m3

V‘= K (ρl/ ρg -1)1/2

K can be found for 18 inches (460mm) tray spacing to be 0.252

V‘=0.6295m/s

Diatop = 0.0.532 m (1.74 ft)

The minimum diameter of the column must be 0.65 m

Height of the column

height of the column can be approximated as

LC =tray spacing x number of trays

LC =6.1 m appx

Pressure drop

Pressure drop across each plate is given by the relation

∆P =(9.81 X 10-3

)( ht)( ρl)

Where,

ht = hd+hw+how+hr

hd = dry pressure drop (due to friction)

hw = weir height

how = weir crest ( liquid level above weir)

hr = residual pressure drop

taking weir height hw =50 mm (2 inches)


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weir length = 0.7 x Dc

weir length = 0.455m

since,

hd = 51(Va/Co)2(ρg/ ρl)

Co = 0.84 (for 10% downcomer area, & hole dia/ plate thickness = 1)

hd= 119.6 mm

how =(750 Lw)/( ρlxlw)

how = 135mm

hw = 50mm

hr = (1.25 x 10-3)/ ρl

hr = 2.38 mm

ht = 307 mm

∆P =(9.81 X 10-3

)( 307)( 525)

∆P =1581 Pa (0.23psi)

Total pressure drop across column ∆Pc

∆Pc = 1581 x 14

∆Pc = 22120 Pa (3.2 psi)

Column specifications

Number of plates 14

Column diameter 0.65 m

Tray spacing 460 mm (18 inches)

Height of column 9.10 m

Weir height 50 mm (2 inches)

Pressure drop 22.12 Kpa (3.2 psi)

Downcomer area 10%


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Pressure At Different Stages

Q

Q

Q

7.6 DESIGNING OF HYDROGEN FEED COMPRESSOR K-101:


114

For First Stage

γ = Cp/(Cp-R)

γ


115

W = W/Ep

For Second Stage

γ = Cp/(Cp-R)

γ


116

W = W/Ep

For Third Stage

γ = Cp/(Cp-R)

γ


117

W = W/Ep


118

For Fourth Stage

γ = Cp/(Cp-R)

γ

W = W/Ep


118

Total Work & Power

CHAPTER 8

COST ESTIMATION

Chapter 8 Cost Estimation

119

CHAPTER # 8

COST ESTIMATION

8.1 COST ESTIMATION:

Feasibility means that the project being considered is technically possible. Economic

feasibility, in addition to acknowledging the technical possibility of a project, further

implies that it can be justified on an economic basis as well. Economic feasibility

measures the overall desirability of the project in financial terms and indicates the

superiority of a single approach over others that may be equally feasible in a technical

sense.

The cost analysis of an industrial process includes capital investment cost,

manufacturing cost and general expense such as income taxes.

8.1.1 Capital investments:

Before an industrial plant can be put into operation, large amount of money must be

supplied to purchase and install the necessary machinery and equipment, land and

service facilities must be obtained and the plant must be erected. Complete with all

pipe controls inn services. In addition it is necessary to have money available for

payment of expenses involved in the plant operation.

8.1.2 Fixed capital:

Fixed capital is that portion of the total capital that is invested in fixed assets (such as

land, buildings, vehicles, and equipment) that stay in the business almost

permanently. The capital needed to supply the necessary manufacturing and plant

facilities is called the fixed-capital investment

It includes

capital necessary for the installed process equipments

All design and construction overheads supervision

All piping, instruments and controls

insulation, foundations, and site preparation


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land, processing buildings, administrative, and other offices, warehouses,

laboratories.

Auxiliary facilities, such as utilities, land and civil engineering work

The fixed capital investment classified in to two sub divisions.

i. Direct Cost

ii. Indirect Cost

8.1.3 Working capital:

Working capital is additional investment which represents operating liquidity

available to a processing plant.

It includes the cost of

Startup

Initial catalyst charge

raw materials and supplies carried in stock

Inventories of intermediates and products

cash kept on hand for monthly payment of operating expenses, such as

salaries, wages etc.

Payable accounts and taxes.

The total capital investment is the sum of fixed and working capital. The ratio of

working capital to total capital investment varies with different companies, but most

chemical plants use an initial working capital amounting to 10 to 20 percent of the

total capital investment. This percentage may increase to as much as 50 percent or

more for companies producing products of seasonal demand because of the large

inventories which must be maintained for appreciable periods of time.

By far the most important item is the raw material expense. Labor is the component of

immediate secondary magnitude. This increased by the fact that pay role over head

http://en.wikipedia.org/wiki/Accounting_liquidity


121

and plant overhead are always calculated fraction of labor expense and that

laboratories charges and supervision maybe estimated similarly if one chooses.

Depreciation, property taxes, insurance and sometimes maintenance and plant

supplied are estimated from the fixed capital investment. Individually there are small

in the manufacturing cost, but together they can represent a sizable total- Utilities take

collectively represent an amount of relative importance in a manufacturing cost.

Royalties on the average are small but should be carefully conceded when large.

Similarly, shipping is usually minor. Packaging expenses are usually small since the

petrochemical industry is primarily bulk supplier. However in particular face of the

industry packaging may prove to be of major importance. General expenses are a

sizable portion of total cost, can be estimated as percentage of manufacturing cost.

8.1.4 Direct cost:

Purchased Equipment Cost = E

Component Percentages of ‗Purchased Equipment

Cost‘ (E)

Purchased equipment Installation 47 %

Instrumentation (installed) 12 %

Piping (installed) 66 %

Electrical (installed) 11 %

Building (including Service) 18 %

Yard improvement 10 %

Service facilities 70 %

Total Direct Cost = D

8.1.5 Indirect cost:

Engineering and supervision 33 % E

Construction Expenses 46 % E

Total Indirect cost I

Total Direct and Indirect Cost D + I

Contractor‘s Fees 5 % (D+I) = x


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Contingency 10 % (D+I)=y

Fixed Capital investment D + I + x + y

Working Capital Investment 0.15 * (D+I+x+y)

Total Plant Cost (TPC) Fixed Capital + Working Capital

Land Cost 2 * TPC

Total Cost TPC + Land Cost

8.2 COST ESTIMATION OF OUR PLANT:

Cost of Equipment:

Cost of 2012 = cost of 2007 × (Index 2012/ Index 2007)

Cost Index of year 2007 = 525.4

Cost Index of year 2012 = 593.8

Equipment Purchased Cost (E):

Equipment 2007 Cost (US $) 2012 Cost (US $)

Drier

12600 14240.35021

Mixer 7800 8815.454892

Compressor 128400 145115.9498

pump 7900 8928.473544

Exchanger E-101 183500 207389.2273

Exchanger E-102 183500 207389.2273

Exchanger E-103 183500 207389.2273

Reactor R-101 31100 35148.80091

Reactor R-102 56300 63629.50133

Distillation Column 53300 60238.94176

Scrubber 4200 4746.783403

Total 852100 963031.9376

8.2.1 Direct cost estimation:

Purchased equipment installation 452625.0107 $

Instrumentation installation 115563.8325 $

Piping installed 636501.0788 $


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Electrical installed 105933.5131 $

Building including services 173345.7488 $

Yard improvement 96303.19376 $

Service facilities 674122.3563 $

Total direct cost 2253494.734 $

8.2.2 Indirect cost estimation:

Engineering and supervision 317800.5394 $

Construction expenses 394843.0944 $

Total direct and indirect cost 2966138.368 $

Miscellaneous,

Contractors fee 148306.9184 $

Contingency 2966138.8368 $

Total plant cost 3922717.991 $

Land cost 7845345.983 $

Total cost 11768153.97 $

Including present worth of catalyst for 4 years life, and given plant life of 16 years at

rate of $ 196/kg.

Present worth of catalyst 1611366 $

Miscellaneous 4541961.6 $

Annual revenues

For 24500 kg/hr and a production capacity of 24 hours a day and 300 days a year

Inflows 37849680 $

Annual expenses

Electricity 651183.16 $

Salaries and wages 65684.211 $

Income tax (40%) 15139872 $


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Sales tax (16%) 6055948.8 $

Net annual revenues = inflows – outflows

Net annual revenues = 12152024 $

8.2.3 Payback period:

Calculating discounted payback period at a MARR of 25%.

End of year 1 = -3657901 $

End of year 2 = 4119394.4 $

Hence 2nd

year is the payback period.

8.3 ECONOMICS OF PLANT LOCATION:

The final choice of the plant site usually involves a presentation of the economic

factors for several equally attractive sites. The exact type of economic study of plant

locations will vary with each company making a study. It should include the

following:

8.3.1 Investment:

Plant

New Money

Existing facilities

Working capital

Annual sales

Cost

Manufacturing

Distributing

Selling

Research

Annual Earnings

Operative

Net after taxes

Net annual return on total investment


125

The limitations of preliminary plant location cost studies should be recognized

pointed out a management. No matter how carefully a survey is prepared, future

trends such as population and marketing shifts, development of competitive processes

and the advent of new industries. Services and transportation facilities cannot be

reliably predicated.

8.4 PLANT LOCATION AND SITE SELECTION:

The location of plant has a crucial effect on the profitability of project and the scope

for future expansion. Many factors are considered when selecting a suitable site. A

brief explanation of each factor is given below:

8.4.1 Raw Materials Supply:

Probably the location of the raw materials of an industry contributes more towards

the choice of a plant site than any other factor. This is especially noticeable in

those industries in which the raw material is inexpensive and bulky and is made

more compact and obtains a high bulk value during the process of manufacturing.

8.4.2 Marketing Area:

For materials that are produced in bulk quantities, such as cement, minerals acids

and fertilizers, where the cost of e product per ton is relatively low and cost of

transportation has a significant fraction of the sale price. The plant should be

located closed to the primary market. This consideration will be less important for

low volume production, high price product such as pharmaceuticals.

8.4.3 Transportation Facilities:

The Transport of material and products to and from the plant will be overriding

consideration in site selection. If practicable, a site should be selected that is

closed to at least two major forms of transport, road, rail, water way (canal or

river) or a sea port. Road transport is being increasingly used and is suitable for

local distribution from a central ware house. Rail transportation will be cheaper

for long distance transport of bulk chemicals. Air transport is convenient and

efficient for the movement of personnel and essential equipment and supplies and

the proximity of the site to a major airport should be considered.


126

8.4.4 Sources of Power:

Power for chemical industry is primarily from coal, water and oil; these fuels

supply (he most flexible and economical sources, in as much as they provide for

generation of steam both for processing and for electricity production power can

be economically developed as a by-product in the most chemical plants. If the

needs are great enough, since the process requirements generally call for low-

pressure steam. The turbines of engines used to generate electricity can be

operated non-condensing and supply exhaust steam for processing purposes.

8.4.5 Availability of Labor:

Labor will be needed for construction of the plant and its operation. Skilled

construction workers will usually be brought in from outside the site area, but here

should be an adequate pool of unskilled labor available locally; and lab our

suitable for training to operate plant. Skilled tradesmen will be needed for plant

maintenance. Local trade union customs and restrictive practices will have to be

considered when assessing the availability and suitability of the local labor for

recruitment and training.

8.4.6 Water Supply:

Water for industrial purpose can be obtained from one of two general sources: the

plant's own source or municipal supply. If the demand for water is larger, it is

more economical for the industry to supply its own water. Such a supply may be

obtained from drilled wells, rivers, lakes, dammed streams or other impounded

supplies. Before a company enters upon any project, it must ensure itself of a

sufficient supply of water for all industrial, sanitary and fire demands, both

present and future.

8.4.7 Effluent Disposal:

All industrial process produce waste products and full consideration must be given

to the difficulties and cost of their disposal. The disposal of toxic and harmful

effluents will be covered by local regulations and appropriate authorities must be

consulted during the initial site survey to determine the standards that must be

met.


127

8.4.8 Local Community Considerations:

The proposed plant must fit in with and be acceptable to the local community. Full

consideration must be given to the safe location of the plant so that it dies not

impose a significant additional risk to the community. On a new site, the local

community must be able to provide adequate facilities for, the plant personnel:

school, banks, housing and recreational and cultural facilities.

8.4.9 Land Considerations:

Sufficient suitable land must be available for the proposed pant and for future

expansion. The land should ideally be flat, well drained and have suitable load

bearing characteristics. A full site evaluation should be made to determine the

need for piling or other special foundation.

8.4.10 Climate:

Adverse climatic conditions at a site will increase costs. Abnormally low

temperature will require the provision of additional insulation and special heating

for equipment and pipe runs. Stronger structures will be need at locations

subjected to strong winds (cyclone hurricane areas) or earthquakes.

8.4.11 Political and Strategic Considerations:

Capital grants, tax concessions, and other inducements are often given by

government's direct new investment to preferred locations such as areas of high

unemployment. The availability of such grants can be over-riding consideration

site selection.

CHAPTER 9

ENVIRONMENT AND SAFETY

Chapter 9 Environment And Safety

129

CHAPTER # 9

ENVIRONMENT AND SAFETY

Petroleum refining is one of the largest industries and a vital part of the national

economy. However, potential environmental hazards associated with refineries have

caused increased concern for communities in close proximity to them. This update

provides a general overview of the processes involved and some of the potential

environmental hazards associated with petroleum refineries.

9.1 DEFINITION OF A PETROLEUM REFINERY:

Petroleum refineries separate crude oil into a wide array of petroleum products

through a series of physical and chemical separation techniques. These techniques

include fractionation, cracking, hydro treating, combination/blending processes, and

manufacturing and transport. The refining industry supplies several widely used

everyday products including petroleum gas, kerosene, diesel fuel, motor oil, asphalt,

and waxes.

9.2 BACKGROUND:

A refinery is an industrial plant for purifying a crude substance. The refining sector

investment in Pakistan has been almost nonexistent since the 1960s.In the late 90s,

Pakistan‘s refining capacity was less than 150k bbl. /day. Pakistan imported over 60%

of its total POL product consumption. At present, Pakistan‘s refining

capacity stands slightly below 300Kbb/day. This was mainly due to the

commencement of PARCO in the late 2000.Almost the refineries work at around 80%

capacity except Byco, which just utilized 45% of its capacity. NRL and PPl operate at

full capacity. Inspite of current condition there is a general lack of refineries; where

Pakistan is facing a deficit 100,000 to 150,000 barrels a day in refining fuel oil and

diesel. There are certain standards that are followed internationally known as EURO 2

and EURO 4 that relate to environmental cleanliness. Neither of these is followed in

Pakistan. The major players or the 5 refineries under OCAC (Oil Companies

Advisory Committee) are:

1. Pak Arab Refinery Complex

2. National Refinery Limited


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3. Pakistan Refinery Limited

4. Attock Refinery Limited

5. Byco Refinery Limited

Two refineries that have been introduced and don‘t come under OCAC. Enar

Petrotech Services Limited and Dohaka Refinery Limited.

9.3 PROCESSES INVOLVED IN REFINING CRUDE OIL:

The process of oil refining involves a series of steps that includes separation and

blending of petroleum products. The five major processes are briefly described below:

9.3.1 Separation Processes:

These processes involve separating the different fractions/ hydrocarbon compounds

that make up crude oil based on their boiling point differences. Crude oil generally is

composed of the entire range of components that make up gasoline, diesel, oils and

waxes. Separation is commonly achieved by using atmospheric and vacuum

distillation. Additional processing of these fractions is usually needed to produce final

products to be sold within the market.

9.3.2 Conversion Processes:

Cracking, reforming, coking, and visbreaking are conversion processes used to break

down large longer chain molecules into smaller ones by heating or using catalysts.

These processes allow refineries to break down the heavier oil fractions into other

light fractions to increase the fraction of higher demand components such as gasoline,

diesel fuels or whatever may be more useful at the time.

9.3.3 Treating:

Petroleum-treating processes are used to separate the undesirable components and

impurities such as sulfur, nitrogen and heavy metals from the products. This involves

processes such as hydro treating, deasphalting, acid gas removal, desalting,

hydrodesulphurization, and sweetening.


131

9.3.4 Blending/Combination Processes:

Refineries use blending/combination processes to create mixtures with the various

petroleum fractions to produce a desired final product. An example of this step would

be to combine different mixtures of hydrocarbon chains to produce lubricating oils,

asphalt, or gasoline with different octane ratings.

9.3.5 Auxiliary Processes:

Refineries also have other processes and units that are vital to operations by providing

power, waste treatment and other utility services. Products from these facilities are

usually recycled and used in other processes within the refinery and are also important

in regards to minimizing water and air pollution. A few of these units are boilers,

wastewater treatment, and cooling towers.

9.4 ENVIRONMENTAL HAZARDS OF PETROLEUM REFINERIES:

Refineries are generally considered a major source of pollutants in areas where they

are located and are regulated by a number of environmental laws related to air, land

and water. Some of the regulations that affect the refining industry include the

following Laws, Rules and Regulations have been issued under the Pakistan

Environmental Protection Act, 1997.

9.4.1 Rules:

National Environmental Quality Standards (self-monitoring and Reporting by

Industries) Rules, 2001

Provincial Sustainable Development Fund (Procedure) Rules, 2001

Pakistan Sustainable Development Fund (Utilization) Rules, 2001

Provincial Sustainable Development Fund (Utilization) Rules, 2003

Pollution Charge for Industry (Calculation and Collection) Rules, 2001

Environmental Tribunal Rules, 1999

Environmental Tribunal Procedures and Qualifications Rules, 2000

Environmental Samples Rules, 2001


132

Hazardous Substances Rules, 2000

Hazardous Substances Rules, 2003

9.4.2 Regulations :

Review of IEE/EIA Regulations, 2000 Pakistan Environmental Protection

Agency (Review of IEE1EIA) Regulations, 2000

National Environmental Quality Standards (Environmental Laboratories

Certification) Regulations, 2000

National Environmental Quality Standards

Draft Hospital waste Management Rules

Draft Composition of Offences and Payment of Administrative Penalty Rules,

1999

9.4.3 Policies &Strategies:

National Environment Policy

National Resettlement Policy March, 2002 (Draft)

National Drinking water Policy (Draft)

National Drinking water Policy

Clean Development Mechanism (CDM)

National Operational Strategy

Here is a breakdown of the air, water, and soil hazards posed by refineries:

9.4.4 Air Pollution Hazards:

Petroleum refineries are a major source of hazardous and toxic air pollutants such as

BTEX compounds (benzene, toluene, ethyl benzene, and xylem). They are also a

major source of criteria air pollutants: particulate matter (PM), nitrogen oxides (Knox),

carbon monoxide (CO), hydrogen sulfide (H2S), and sulfur dioxide (SO2). Refineries

also release less toxic hydrocarbons such as natural gas (methane) and other light

volatile fuels and oils. Some of the chemicals released are known or suspected cancer-

causing agents, responsible for developmental and reproductive problems. They may


133

also aggravate certain respiratory conditions such as childhood asthma. Along with

the possible health effects from exposure to these chemicals, these chemicals may

cause worry and fear among residents of surrounding communities. Air emissions can

come from a number of sources within a petroleum refinery including: equipment

leaks (from valves or other devices); high-temperature combustion processes in the

actual burning of fuels for electricity generation; the heating of steam and process

fluids; and the transfer of products. Many thousands of pounds of these pollutants are

typically emitted into the environment over the course of a year through normal

emissions, fugitive releases, accidental releases, or plant upsets. The combination of

volatile hydrocarbons and oxides of nitrogen also contribute to ozone formation, one

of the most important air pollution problems in the United States.

9.4.5 Water Pollution Hazards:

Refineries are also potential major contributors to ground water and surface water

contamination. Some refineries use deep-injection wells to dispose of wastewater

generated inside the plants, and some of these wastes end up in aquifers and

groundwater. These wastes are then regulated under the Safe Drinking Water Act

(SDWA). Wastewater in refineries may be highly contaminated given the number of

sources it can come into contact with during the refinery process (such as equipment

leaks and spills and the desalting of crude oil). This contaminated water may be

process wastewaters from desalting, water from cooling towers, storm water,

distillation, or cracking. It may contain oil residuals and many other hazardous

wastes. This water is recycled through many stages during the refining process and

goes through several treatment processes, including a wastewater treatment plant,

before being released into surface waters. The wastes discharged into surface waters

are subject to state discharge regulations and are regulated under the Clean Water Act

(CWA). These discharge guidelines limit the amounts of sulfides, ammonia,

suspended solids and other compounds that may be present in the wastewater.

Although these guidelines are in place, sometimes significant contamination from past

discharges may remain in surface water bodies.

9.4.6 Soil Pollution Hazards:

Contamination of soils from the refining processes is generally a less significant

problem when compared to contamination of air and water. Past production practices


134

may have led to spills on the refinery property that now need to be cleaned up.

Natural bacteria that may use the petroleum products as food are often effective at

cleaning up petroleum spills and leaks compared to many other pollutants. Many

residuals are produced during the refining processes, and some of them are recycled

through other stages in the process. Other residuals are collected and disposed of in

landfills, or they may be recovered by other facilities. Soil contamination including

some hazardous wastes, spent catalysts or coke dust, tank bottoms, and sludge from

the treatment processes can occur from leaks as well as accidents or spills on or off

site during the transport process.

9.5 MATERIAL SAFETY DATA SHEET:

Material name: Light Straight Run Naphtha

Synonym(s): LSR; LSR Gasoline; Light Straight Run; Light Straight Run

Gasoline; Gasoline - Straight-Run, Topping-Plant

Physical State Liquid.

Appearance Colorless to light yellow liquid.

9.5.1 Emergency Overview DANGER!

Extremely flammable liquid and vapor - vapor may cause flash fire. Will be easily

ignited by heat spark or flames. Heat may cause the containers to explode. Harmful if

inhaled, absorbed through skin, or swallowed. Aspiration may cause lung damage.

Irritating to eyes, respiratory system and skin. In high concentrations, vapors and

spray mists are narcotic and may cause headache, fatigue, dizziness and nausea.

Contains benzene, Cancer hazard, Mutagen, may cause heritable genetic damage.

May cause adverse reproductive effects -such as birth defects, miscarriages, or

infertility. Hydrogen sulfide, a highly toxic gas, may be present or released. Signs and

symptoms of overexposure to hydrogen sulfide include respiratory and eye irritation,

dizziness, nausea, coughing, a sensation of dryness and pain in the nose, and loss of

consciousness. Odor does not provide a reliable indicator of the presence of hazardous

levels in the atmosphere. Prolonged exposure may cause chronic effects. Toxic to

aquatic Organisms. May cause long-term adverse effects in the aquatic environment.


135

9.5.2 OSHA Regulatory Status:

This product is considered hazardous under 29 CFR 1910.1200 (Hazard

Communication).

9.5.3 Potential Health Effects:

9.5.3.1 Eyes: Contact may irritate or burn eyes. Eye contact may result in corneal

injury.

9.5.3.2 Skin: Harmful if absorbed through skin. Irritating to skin. Frequent or

prolonged contact may defat and dry the skin, leading to discomfort and dermatitis.

9.5.3.3 Inhalation: Harmful if inhaled. Irritating to respiratory system. In high

concentrations, vapors and spray mists are narcotic and may cause headache, fatigue,

dizziness and nausea. May cause breathing disorders and lung damage. May cause

cancer by inhalation. Prolonged inhalation may be harmful.

9.5.3.4 Ingestion: Harmful if swallowed. Ingestion may result in vomiting; aspiration

(breathing) of vomiting into lungs must be avoided as even small quantities may

result in aspiration pneumonitis. Irritating to mouth, throat, and stomach.

9.5.3.5 Target organs: Blood. Eyes. Liver, Respiratory system, Skin, Kidneys,

Central nervous system.

9.5.3.6 Chronic effects: Cancer hazard. Contains material which may have

reproductive toxicity, teratogenetic or Mutagenic effects. Liver injury may occur.

Kidney injury may occur. May cause central nervous system disorder (e.g., narcosis

involving a loss of coordination, weakness, fatigue, mental confusion and blurred

vision) and/or damage. Frequent or prolonged contact may defat and dry the skin,

leading to discomfort and dermatitis.

9.5.3.7 Signs and symptoms: Irritation of nose and throat. Irritation of eyes and

mucous membranes. Skin irritation, Unconsciousness, Corneal damage, Narcosis,


136

Cyanosis (blue tissue condition, nails, lips, and/or skin). Decrease in motor functions.

Behavioral changes, Edema, Liver enlargement. Jaundice, Conjunctivitis. Proteinuria,

Defatting of the skin rash.

9.5.3.8 Potential environmental effects: Toxic to aquatic organisms. May cause long-

term adverse effects in the aquatic environment.

9.5.4 Composition:

component percentage

Gasoline, straight-run, topping-plant 0 - 100

Pentane 0 - 35

Hexane (Other Isomers) 0 - 25

Pentane Isomers Mixture 0 - 25

n-Hexane 0 - 20

Benzene 0 - 5

Cyclohexane 0 - 5

Cyclopentane 0 - 5

Methyl cyclohexane 0 - 5

n- Heptanes 0 - 5

n-Butane 0 - 4

Hydrogen sulfide < 1

9.5.5 First Aid Measures:

9.5.5.1 Eye Contact :

Immediately flush eyes with plenty of water for at least 15 minutes. Remove contact

lenses, if present and easy to do. Continue rinsing. Get medical attention.

9.5.5.2 Skin Contact :

Remove contaminated clothing and shoes. Wash off immediately with soap and

plenty of water. Get medical attention if irritation develops or persists. Wash clothing

separately before reuse. Destroy or thoroughly clean contaminated shoes. If high

pressure injection under the skin occurs, always seek medical attention.

9.5.5.3 Inhalation:


137

Move to fresh air. If breathing is difficult, give oxygen. If not breathing, give artificial

respiration. Get medical attention.

9.5.5.4 Ingestion:

Rinse mouth thoroughly. Do not induce vomiting without advice from poison control

center. Do not give mouth-to-mouth resuscitation. If vomiting occurs, keep head low

so that stomach content does not get into the lungs. Get medical attention

immediately.

9.5.5.5 Notes To Physician:

In case of shortness of breath, give oxygen. Keep victim warm. Keep victim under

observation. Symptoms may be delayed.

9.5.5.6 General Advice:

If exposed or concerned: get medical attention/advice. Ensure that medical personnel

are aware of the material(s) involved, and take precautions to protect themselves.

Show this safety data sheet to the doctor in attendance. Wash contaminated clothing

before re-use.

9.5.6 Fire Fighting Measures:

9.5.6.1 Extinguishing Media:

Suitable Extinguishing Media: Foam, CO2 or dry powder.

For Large Fire Use: Water.

Unsuitable Extinguishing Media: Do not use water jet.

9.5.6.2 Special Hazards Arising From The Substance Or Mixture:

Vapor may create explosive atmosphere. The vapor is heavier than air; beware of pits

and confined spaces. May give off toxic fumes in a fire. Carbon monoxide, Carbon

dioxide and various hydrocarbons.


138

9.5.6.3 Advice For Fire-Fighters:

A self-contained breathing apparatus and suitable protective clothing should be worn

in fire conditions. Keep fire exposed containers cool by spraying with water.

Flash Point (°C): < 0

Flammable Limits (Lower) (%v/v): 1

Flammable Limits (Upper) (%v/v): 10

Auto Ignition Temperature (°C): > 250

9.5.7 Accidental Release Measures:

9.5.7.1 Personal Precautions:

Keep unnecessary personnel away. Local authorities should be advised if significant

spills cannot be contained. Keep upwind. Keep out of low areas. Ventilate closed

spaces before entering. Do not touch damaged containers or spilled material unless

wearing appropriate protective clothing. See Section 8 of the MSDS for Personal

Protective Equipment.

9.5.7.2 Environmental Precautions:

Gasoline may contain oxygenated blend products (Ethanol, etc.) that are soluble in

water and therefore precautions should be taken to protect surface and groundwater

sources from contamination. If facility or operation has an "oil or hazardous substance

contingency plan", activate its procedures. Stay upwind and away from spill. Wear

appropriate protective equipment including respiratory protection as conditions

warrant. Do not enter or stay in area unless monitoring indicates that it is safe to do

so. Isolate hazard area and restrict entry to emergency crew. Extremely flammable.

Review Fire Fighting Measures, Section 5, before proceeding with lean up. Keep all

sources of ignition (flames, smoking, flares, etc.) and hot surfaces away from release.

Contain spill in smallest possible area. Recover as much product as possible (e.g. by

vacuuming). Stop leak if it can be done without risk. Use water spray to disperse

vapors. Use compatible foam to minimize vapor generation as needed. Spilled

material may be absorbed by an appropriate absorbent, and then handled in

accordance with environmental regulations. Prevent spilled material from entering

sewers, storm drains, other unauthorized treatment or drainage systems and natural

waterways. Contact fire authorities and appropriate federal, state and local agencies. If


139

spill of any amount is made into or upon navigable waters, the contiguous zones, or

adjoining shorelines, contact the National Response Center

9.5.7.3 Methods For Containment:

Eliminate all ignition sources (no smoking, flares, sparks, or flames in immediate

area). Stop leak if you can do so without risk. This material is a water pollutant and

should be prevented from contaminating soil or from entering sewage and drainage

systems and bodies of water. Dike the spilled material, where this is possible. Prevent

entry into waterways, sewers, basements or confined areas.

9.5.7.4 Methods For Cleaning Up:

Use non-sparking tools and explosion-proof equipment. Small Spills: Absorb spill

with vermiculite or other inert material, then place in a container for chemical waste.

Clean surface thoroughly to remove residual contamination. This material and its

container must be disposed of as hazardous waste. Large Spills: Use a non-

combustible material like vermiculite, sand or earth to soak up the product and place

into a container for later disposal. Prevent product from entering drains. Do not allow

material to contaminate ground water system. Should not be released into the

environment.

9.5.7.5 Other Information:

Clean up in accordance with all applicable regulations.

9.5.8 Handling And Storage:

9.5.8.1 Handling:

Wear personal protective equipment. Do not breathe dust/fume/gas/mist/vapors/spray.

Avoid contact with eyes, skin, and clothing. Do not taste or swallow. Avoid

prolonged exposure. Use only with adequate ventilation. Wash thoroughly after

handling. The product is extremely flammable, and explosive vapor/air mixtures may

be formed even at normal room temperatures. DO NOT handle, store or open near an

open flame, sources of heat or sources of ignition. Protect material from direct

sunlight. Take precautionary measures against static discharges. All equipment used

when handling the product must be grounded. Use non-sparking tools and explosion-


140

proof equipment. When using, do not eat, drink or smoke. Avoid release to the

environment.

9.5.8.2 Storage :

Flammable liquid storage. Do not handle or store near an open flame, heat or other

sources of ignition. This material can accumulate static charge which may cause spark

and become an ignition source. The pressure in sealed containers can increase under

the influence of heat. Keep container tightly closed in a cool, well-ventilated place.

9.5.9 Exposure Controls/Personal Protection:

9.5.9.1 Appropriate Engineering Controls:

Provide adequate ventilation, including appropriate local extraction, to ensure that the

occupational exposure limit is not exceeded occupational Exposure Limit assigned.

9.5.9.1.2 Personal Protection

9.5.9.1.2.1 Eye/face protection: Goggles giving complete protection to eyes

9.5.9.1.2.2 Skin protection: Protective gloves

9.5.9.1.2.3 Respiratory protection: In case of insufficient ventilation, wear suitable

respiratory equipment


141

9.5.10 Physical And Chemical Properties

Information on basic physical and chemical properties

Appearance: Liquid.

Color: Pale yellow.

Odour: Hydrocarbon.

Boiling Point (°C): < 35

Flash Point (°C):<0

Flammable Limits (Lower) (%v/v) : 1

Flammable Limits (Upper) (%v/v): 10

Vapor Pressure (mm Hg): 200 (@ 20°C)

Specific Gravity: 0.70-0.80

Solubility (Water): Negligible.

Partition Coefficient:

(n-Octane/water) 1.0-8.0

Auto Ignition Temperature (°C): >250

Viscosity: 1 mm2/s (@ 20°C)

Explosive Properties: Vapor may create explosive

atmosphere.

Oxidizing Properties: Not oxidizing.

Vapor Density (Air=1):>2

Other information

Conductivity: 15-35

9.5.11 Stability And Reactivity:

Reactivity Reacts with Strong oxidizing agents.

Chemical stability Stable under normal

conditions.

Possibility of hazardous reactions No information available.

Conditions to avoid Keep away from heat, sources of


142

ignition and direct sunlight.

Incompatible materials Oxidizing agents.

Hazardous Decomposition Product(s) May give off toxic fumes in a

fire. Carbon monoxide, Carbon

dioxide and various hydrocarbons

9.5.12 Toxicological Information:

Ingestion LD50 (oral/rat):>5000 mg/kg

Inhalation LC50 (inhalation/rat):>5.2 mg/l/4

h

Skin Contact LD50 (dermal/rabbit):>2000

mg/kg

Eye Contact No information available.

Skin corrosion/irritation Irritating to skin.

Serious eye damage/irritation May cause eye irritation.

Respiratory or skin sensitization Negative.

Mutagenicity May cause heritable genetic

damage.

Carcinogenicity May cause cancer.

Reproductive toxicity Suspected of damaging

fertility.

Suspected of damaging the unborn

child.

STOT-single exposure Vapors may cause drowsiness and

dizziness.

STOT-repeated exposure Negative.

Aspiration hazard Risk of aspiration .Aspiration of

Liquid may cause pulmonary

edema.

CHAPTER 10

INSTRUMENTATION AND

CONTROL

Chapter 10 Instrumentation and Control

143

CHAPTER # 10

INSTRUMENTATION AND CONTROL

The important feature common to all process is that a process in never in a state of

static equilibrium except for a very short period of time and process is a dynamic

entity subject to continual upset or disturbance which' tend to drive it away from the

desired state of equilibrium the process must then be manipulated upon or

corrected to derive some disturbance bring about only transient effect in the process

behavior. These passes away and the never occur again. Others may apply periodic or

cycle forces which may make the process respond in a cyclic or periodic fashion.

Most disturbances are completely random with respect to time a show no repetitive

pattern. Thus their occurrence may be expected hut cannot be predicated at any

particular time. If a process is to operate efficiently, disturbances in the process must

be controlled.

A process is designed for a particular objective or output and is then found.

Sometimes by trial and error and sometimes by referring from the previous,

experience that control of a particular variable associated with some stages of the

process is necessary to achieve the desired efficiency.

Each process will have associated with it number of variables which are independent

of the process and/ or its operation and which are likely to change at random. Each

such change will lead to changes in the dependent variables of the process one of

which is selected as bring indicative of successfully operation. One of the input

variable will be manipulated to cause further changes in the output variable will be

manipulated to cause further changes in the output variable the original

conditions, Process may controlled more precisely to give more uniform and

higher quality products by the application of automatic control, often leading to

higher profits additionally, process which response too rapidly to be controlled by

human operators can be controlled automatically. Automatic control is also

beneficial in certain remote, hazardous or routine operations. After a period of

experimentation, computers are now being used to operate automatic ally control


144

processing systems, which may too large and too complex for effective direct

human control.

Since process profit is usually the most important benefit to obtained by

applying automatic control. The quality of control and its cost should be

compared with the economic return expected and the process technical

objective. The economic return includes reduced operating costs, maintenance and of

the specification product along with improved process operability and increased

throughout.

10.1 COMPONENTS OF THE CONTROL SYSTEM:

10.1.1 Process:

Any operation of series of operations that produce a desired final result is a process.

In this discussion the process is the purification of natural

10.1.2 Measuring Means:

As all the parts of the control system, measuring element, is perhaps the most

important. If the measurements are not made properly the remainder of the system

cannot operate satisfactorily. The measured variable is chosen to represent the desired

condition in the process.

10.2 ANALYSIS OF MEASUREMENT:

10.2.1 Variables to be Measured:

a. Pressure Measurement

b. Temperature Measurement

c. Flow Rate Measurement

d. Level Measurement

10.2.2 Variables to be Recorded:

Indicated temperature, composition, pressure etc.


145

10.3 CONTROLLER:

The controller is the mechanism that responds to any error indicated by the

error detecting mechanism. The output of the controller is some predetermined

function of the error. There are three types of controllers.

1. Proportion action which moves the control valve indirect proportion to

the magnitude of the error.

2. Integral action (reset) which moves the control valve based on the time

integral of the error and the purpose of integral actions is to drive the process

back to .its set point when it has been disturbed.

3. Ideal derivative action and its purpose are to anticipate where the process

is heading by cooking at the time a rate of change of error. The final

control element receives the signal from the controller and by some

predetermined relationship changes the energy input to the process.

10.4 CHARACTERISTICS OF CONTROLLER:

In general the process controllers can be classified as

a. Pneumatic controllers

b. Electronic controllers

c. Hydraulic controllers

While dealing with the gases, the controller and the final control element may

be pneumatically operated due to the following reasons.

i. The pneumatic controller is very rugged and almost free of maintenance.

The maintenance men have not had sufficient training and background in

electronics, so pneumatic equipment is simple.

ii. Pneumatic controller appears to be safer in a potentially explosive

atmosphere which is often present in the industry.

iii. Transmissions distances are short pneumatic and electronic transmissions

system are generally equal up to about 200 to 300 feet. Above this distance

electronic system beings to offer savings.


146

10.5 MODES OF CONTROL:

The various types of control are called modes, and they determine type of

response obtained. In other words these describe the action of controller that is the

relationship of output of output signal to the input or error signal. It must be noted

that is error that achieve the controller. The four basic mode of control are:

1. On-off control

2. Integral control

3. Proportional control

4. Rate or derivative control

In industry purely integral, proportional or derivative modes seldom occur alone in

the control system. The on-off controller is the controller with very high gain. In this

case the error signal at once off the valve or any other parameter upon which it sites

or completely sets system.

10.6 ALARMS AND SAFETY TRIPS:

Alarms are used to alert operators of serious and potentially hazardous,

deviations in process conditions, key instruments are fitted with switches and relays

to operate audible and visual alarms on the control panels.

The basic components of an automatic trip system are

1. A sensor to monitor the control variable and provide and output signal when a

preset value is exceeded (the instrument).

2. A link to transfer the signal to the activator, usually consisting of a

system of pneumatic or electric relays.

3. An activator to carry out the required action close or open a valve, switch off a

motor.

10.7 CONTROL LOOPS:

For instrumentation and control of different sections and equipments of plants,

following control loops are most often used.

1. Feed backward control loop


147

2. Feed forward control loop

3. Ratio control loop

4. Auctioneering control loop

5. Split range control loop

6. Cascade control loop

Here is given a short outline of these control schemes, so that to justify our selection

of a control loop for specified equipment.

10.8 FEED BACK CONTROL LOOP:

A method of control in which a measured value of a process variable is compared

with the desired value of the process variable and any necessary action is taken.

Feedback control is considered as the basic control loops system. Its disadvantage

lies in its operational procedure. For example if a certain quantity is entering in a

process, then a monitor will be there at the process to note its value. Any changes

from the set point will be sent to the final control element through the controller so

that to adjust the incoming quantity according to desired value (set point). But in fact

change has already occurred and only corrective action can be taken while using

feedback-control system.

10.9 FEED FORWARD CONTROL LOOP:

A method of control in which the value of a disturbance is measured, and action is

taken to prevent the disturbance by changing the value of a process variable. This is a

control method designed to prevent errors from occurring in a process variable.

This control system is better than feedback control because it anticipates the change in

the process variable before it enters the process takes the preventive action. While in

feedback enter system action is taken after the change has occurred.

10.10 RATIO CONTROL:

A control loop in which, the controlling element maintains a predetermined ratio of

one variable to another. Usually this control loop is attached to such a system

where two different streams enter a vessel for reaction that may be of any kind.

To maintain the stoichiometric quantities of different streams this loop is used

so that to ensure proper process going on in the process vessel.


148

10.11 AUCTIONEERING CONTROL LOOP:

This type of control loop is normally used for a huge vessel where, readings of a

single variable may be different at different locations. This type of control loop

ensures safe operation because it employs all the readings of different locations

simultaneously, and compares them with the set point, if any of those readings is

deviating from the set point then the controller sends appropriate signal to final

control element.

10.12 SPLIT RANGE LOOP:

In this loop controller is per set with different values corresponding to different action

to be taken at different conditions. The advantage of this loop is to maintain the

proper conditions and avoid abnormalities at very differential levels.

10.13 CASCADE CONTROL LOOP:

This is a control in which two or more control loops are arranged so that the output of,

one controlling element adjusts the set point of another controlling element. This

control loop is used where proper and quick control is difficult by simple feed forward

or feed backward control. Normally first loop is a feedback control loop. We have

selected a cascade control loop for our heat exchanger in order to get quick on proper

control.

10.14 INTERLOCKS:

Where it is necessary to follow a fixed sequence of operations for example, during a

plant start-up and shut-down, or in batch operations. Interlocks are includes to prevent

operators departing from the required sequence. They may be incorporated in the

control system design, as pneumatic or electric relays or may be mechanical

interlocks.

10.15 CONTROL OF HEAT EXCHANGER:

10.15.1 The Normal Way:

The normal method of controlling a heat exchanger is to measure exit

temperature of process fluid and adjust input of heating or cooling medium to

hold the desired temperature.


149

To stabilize this feedback control, in almost all cases the control must have a

wide proportional band (i.e., wide range of exit temperature change operates the

control valve through full stroke). The proportional band is determined by gain of

other components in the control loop by process considerations.

Since heat-exchanger control require a wide proportional band for stabilization,

reset response (rate of change of heating medium How proportional to exit

temperature.

deviation from controller set point is normally required to correct for offset in

the controlled variable (temperature). It there are process load change and reset

response can be eliminated in cases where disturbance such as heating fluid header

pressure, product flow rate or inlet temperature changes have small effects relative to

desired tolerance on the controlled variable.

When throughout to a heat exchanger is changed rapidly a short-term error in control

temperature results. The magnitude and duration of this error can normally be reduced

by a factor of two by adding derivative response to the control mechanism and

adjusting it properly. In derivative responses, heating fluid flow rate is proportional to

rate or change of temperature derivation from the set point.

10.15.2 A Pressure Cascade Control:

A pressure cascade control system cascades output of a standard three action

temperature controller into the set point of a pressure controller. It achieves a more

rapid recovery to process load disturbances in a shell-and-tube exchanger than can be

obtained without the pressure controller. Heating fluid to the heater is regulated

by the pressure controller which is normally provided with proportional and reset

responses. Load change is rapidly sensed by a change is shell pressure which is

compensated for by the pressure controller. The temperature control system senses the

residual error and resets the pressure control set point.

10.15.3 Bypass Improves Control of Slow-Response Exchanger:

In certain cascade, the time response characteristic of heat exchanger is too slow to

hold temperature deviations resulting from load changes within desired tolerances. In


150

some of these cases, the transient characteristic of the heat exchanger can be

circumvented by by- passing the heater with a parallel line and bleeding cold process

fluid with hot fluid from the heater. In the by-pass system care must be taken in sizing

valves to obtain the-desired flow sprit with adequate flow versus steam travel

characteristics. Thermal elements response time is particularly important since this tie

constant is a major factor influencing performance of the system.

10.15.4 Flow Controllers:

These are used to control tin-feed rate into a process unit Orifice plates are by far the

most type of How-rate sensor. Normally orifice plates arc designed to give pressure

drops in the range of 20 to 200 inch of water Venture tubes amend turbine meter are

also used.

10.15.5 Temperature controller:

Thermocouples are the most commonly used temperature sensing device. The two

dissimilar wires produce a millivolt emf that varies with the ―hot- functions‖

temperature. Iron constant to thermocouples are commonly used over the 0 to 1300 F.

temperature range.

10.15.6 Pressure Controller:

Bourdon tubes, bellows and diaphragms are used to sense pressure and differential

pressure. For example, in mechanical system the process pressure force is balanced by

the movement of a spring. The spring positing can be related to process pressure.

10.15.7 Level Indicator:

Liquid levels are detected in a variety of ways. The three common are

1. The following the position of a float that is lighter than the fluid.

2. Measuring one apparent-weight of a heavy cylinder as it is buoyed up more or

less by the liquid (they are called displacement meters).

3. Measuring the difference in static pressure between two fixed elevations, one

in the vapour above the liquid and the other under the liquid surface.

The differential pressure between the two level taps is directly related to the

liquid level in the vessel.


151

10.15.8 Transmitter:

The transmitter is the interface between the process and its control system. The Job of

the transmitter is to convert the sensor signal (millivolts, mechanical movement,

pressure difference etc.) into a control signal 3 to 15 psig air pressure signal, 1 to 5 10

to 50 milli ampere electrical signal etc.

10.15.9 Control Valves:

The interface with the process at the other end of the control loop is made by the final

control element in an automatic control valves control the flow of heating fluid the

open or close and orifice opening as the system is raised or lowered.

152

REFERENCES

1. M.A Fahim, Fundamentals of Petroleum Refining, 1st edition, Elsevier ,2010

2. J.H Gray, Petroleum Refining Technology and Economics, 4th

edition, Marcel

Dekker 2001

3. Serge Raseev, Thermal and Catalytic Processes in Petroleum Refining, Marcel

Dekker 2003

4. Ludwig, E.E, ‖ Applied process design‖ , 3rd

ed, vol. 2, Gulf

Professional Publishers, 2002.

5. Ludwig, E.E, ―Applied Process Design, 3rd ed, vol. 3, Gulf

Professional Publishers, 2002.

6. McKetta, J.J., ―Encyclopedia of chemical Processing and Design‖, Executive

ed, vol. 1, Marcel Dekker Inc, New York, 1976.

7. Levenspiel, O., ―Chemical Reaction Engineering:, 3rd ed ,John Wily and

Sons Inc., 1999.

8. Peters, M.S. and Timmerhaus ,K.D., ―Plant Design and Economics for

Chemical Engineering ―, 5th ed, McGraw Hill, 1991.

9. Rase, H.F., ―Fixed Bed Reactor Design and Diagnostics, Butterworth

Publishers, 1990.

10. Frank L., Evans Jr. ―Equipment Design Hand Book For Refineries &

Chemical Plants‖ Vol 2, 2nd Ed., 1980,

11. Peacock, D.G.,‖ Coulson & Richardson‘s Chemical engineering‖,

3rded,vol,Butterworth Heinenann, 1994.

12. Kern D.Q., ―Process Heat Transfer‖, McGraw H ill Inc.,2000.

13. Mcabe, W.L, ―Unit Operations of Chemical Engineering ―,5th

ed, McGraw

Hill, Inc,1993.

14. Perry, R.H and D.W. Green (eds): Perry‘s Chemical Engineering Hand Book,

7 thed. McGraw Hill New York, 1997.

15. Sinnot, R.K.,‖Coulson & Richardson’s Chemical Engineering‖, 2nd

ed,

vol.6, Butterword Heinenann, 1993.

153

16. Rohsenow,Hartnett,Ganic ―Hand Book of Heat Transfer Application‖ 2nd

edition.

17. Fogler H.S. ―Elements of Chemical Reaction Engineering‖ 2nd Edition.

18. W.L.Nelson. ―Petroleum Refinery Engineering‖4th

Ed ,McGraw Hill.

19. Kern, Donald Q:―Process Heat Transfer‖ , McGraw-Hill International Edition

,New York

20. W.L. Nelson: ―Petroleumner Refiy Engineering‖ Fourth Edition, McGraw-Hill,

New York.

21. Kirk: ―Encyclopedia of Chemical Technology ― John Willey and Sons, New

York

22. Macketta, John J: ―Encyclopedia of chemical Processing and Design

Marceer Dekker, INC., New York

23. Warren M. Rohenson: ―Hand book of Heat Transfer ―, McGrawHill, New York

154

APPENDICES

A Components Properties

B Thermodynamic Properties

C Equilibrium Constants

D Graphs used in the designing of Compressor, pump,

heat exchanger and Distillation column

155

Components

Boiling

Temperature C

Mol Wt

Critical

Pressure Kpa

Critical Temp

C

APPENDIX A

Hydrogen -252.595 2.016 1315.5 -239.71 Methane -161.525 16.0429 4640.68 -82.451 Ethane -88.6 30.0699 4883.85 32.278 Propane -42.102 44.097 4256.66 96.748 n-Butane -0.50199 58.124 3796.62 152.049 n-Pentane 36.059 72.151 3375.12 196.45 n-Hexane 68.73 86.1779 3031.62 234.748 n-Heptane 98.429 100.205 2736.78 267.008 i-Butane -11.73 58.124 3647.62 134.946 i-Pentane 27.878 72.151 3333.59 187.248 2-Mpentane 60.261 86.1779 3010.36 224.347 3-Mpentane 63.27 86.1779 3123.84 231.299 22-Mbutane 49.731 86.1779 3880.62 231.299 23-Mbutane 57.977 86.1779 3126.87 226.83 2-Mhexane 90.049 100.205 2733.62 257.219 3-Mhexane 91.847 100.205 2813.79 262.1 22-Mpentane 79.191 100.205 2773.26 247.35 23-Mpentane 89.778 100.205 2908.02 264.198 24-Mpentane 80.493 100.205 2736.78 246.639 33-Mpentane 86.059 100.205 2945.51 263.248 3-Epentane 93.472 100.205 2890.8 267.49 Benzene 80.089 78.11 4924.39 288.948 Toluene 110.649 92.1408 4100.04 318.649 Cyclopentane 49.248 70.135 4508.95 238.45 Mcyclopentan 71.809 84.1619 3789.55 259.55 Cyclohexane 80.73 84.16 4053 280.05 Ecyclopentan 103.467 98.189 3397.62 296.37 Mcyclohexane 100.929 98.189 3475.37 298.948 223-Mbutane 80.876 100.205 2953.62 258.019

H2O 99.998 18.0151 22120 374.149

CCl4 76.748 153.822 4559.99 283.25

156

Heat of

Combustion

kJ/Kmol

Heat of

Formation

kJ/Kmol

MON

RON

Flash point

Freez point

-241942 0 130 -259.25

-802703 -74900 120 -182.75

-1.43E+06 -84738 100.789 111.378 -182.75

-2.04E+06 -103890 97.1 112.135 -187.65

-2.66E+06 -126190 89.6 93.8 -138.15

-3.27E+06 -146490 62.6 61.7 -40.15 -130.15

-3.89E+06 -167290 26 24.8 -21.15 -95.15

-4.50E+06 -187890 0 0 -4.15 -90.15

-2.65E+06 -134590 97.6 101.426 -159.15

-3.27E+06 -154590 90.3 92.3 -56.15 -160.15

-3.85E+06 -174390 73.5 73.4 -35.15 -153.15

-3.88E+06 -171690 74.3 74.5 -32.15 -163.15

-3.87E+06 -185690 93.4 91.8 -48.15 -99.15

-3.88E+06 -177890 94.3 100 -29.15 -128.15

-4.50E+06 -195090 46.4 42.4 -23.15 -118.15

-4.50E+06 -192390 55.8 52 -4.15 -119.15

-4.49E+06 -206290 95.6 92.8 -15.15 -124.15

-4.49E+06 -199390 88.5 91.1 -15.15 -4.49E+06 -202090 83.8 83.1 -12.15 -119.15

-4.49E+06 -201690 86.6 80.8 -19.15 -134.15

-4.50E+06 -189790 69.3 65 -12.15 -118.15

-3.17E+06 82977 101 106 -11.15 5.85

-3.77E+06 50029 103.524 120.083 3.85 -95.15

-3.10E+06 -77288 84.9 101.426 -40.15 -94.15

-3.71E+06 -106790 80 91.3 -27.15 -142.15

-3.69E+06 -123190 77.2 83 -20.15 6.85

-4.32E+06 -127190 61.2 67.2 -4.15 -138.15

-4.29E+06 -154890 71.1 74.8 -6.15 -126.15

-4.49E+06 -204890 101 100 -24.15 -24.15

- -241814

-258069 -100488

157

13 32 101.3 9.183 -107.9 0 0.1641 6.02E-04 2 91 190.4 101.3 31.35 -1308 0 -3.261 2.94E-05 2

133 305.4 101.3 44.01 -2569 0 -4.976 1.46E-05 2 145 369.8 101.3 52.38 -3491 0 -6.109 1.12E-05 2 170 425.2 101.3 66.94 -4604 0 -8.255 1.16E-05 2 165 408.1 101.3 58.78 -4137 0 -7.017 1.04E-05 2 195 469.6 101.3 63.33 -5118 0 -7.483 7.77E-06 2 220 460.4 101.3 66.76 -5059 0 -8.089 9.25E-06 2 260 433.8 101.3 69.98 -4845 0 -8.701 1.11E-05 2 220 507.5 101.3 70.43 -6056 0 -8.379 6.62E-06 2 230 497.5 101.3 72.46 -5929 0 -8.765 7.62E-06 2 235 504.4 101.3 70.35 -5909 0 -8.419 7.06E-06 2 225 488.8 101.3 56.69 -5087 0 -6.384 5.41E-06 2 235 500 101.3 67.02 -5625 0 -7.959 6.96E-06 2 230 540.2 101.3 78.33 -6947 0 -9.449 6.48E-06 2 230 530.4 101.3 75.79 -6688 0 -9.1 6.44E-06 2 235 535.3 101.3 74.79 -6650 0 -8.95 6.30E-06 2 225 520.5 101.3 70.43 -6198 0 -8.363 6.29E-06 2 230 537.3 101.3 70.99 -6430 0 -8.391 5.88E-06 2 225 519.8 101.3 71.35 -6255 0 -8.497 6.39E-06 2 225 536.4 101.3 77.56 -6450 0 -9.517 7.89E-06 2 265 540.6 101.3 78.75 -6816 0 -9.568 6.93E-06 2 250 531.2 101.3 69.23 -6100 0 -8.213 6.30E-06 2 213 552 101.3 169.7 -1.03E+04 0 -23.59 2.09E-05 2

178.2 591.8 101.3 76.45 -6995 0 -9.164 6.23E-06 2 288 511.6 101.3 51.84 -4915 0 -5.623 4.80E-06 2 288 532.7 101.3 71.34 -6030 0 -8.572 7.17E-06 2 293 553.2 101.3 70.98 -6187 0 -8.465 6.45E-06 2

376.6 569.5 101.3 98.91 -7885 0 -12.58 8.90E-06 2 298 572.1 101.3 72.24 -6555 0 -8.597 5.97E-06 2 275 647.3 101.3 65.93 -7228 0 -7.177 4.03E-06 2 250 556.4 101.3 74.22 -6240 0 -8.987 7.19E-06 2

APPENDIX B

Antoine Equation ln(P) = a + b/(T + c) + d*ln(T) + e*T^f

Tmin Tmax Default Q a b c d e f

Hydrogen Methane Ethane

Propane n-Butane i-Butane

n-Pentane i-Pentane

22-Mpropane n-Hexane

2-Mpentane 3-Mpentane 22-Mbutane 23-Mbutane n-Heptane 2-Mhexane 3-Mhexane

22-Mpentane 23-Mpentane 24-Mpentane 33-Mpentane 3-Epentane

223-Mbutane Benzene Toluene

Cyclopentane Mcyclopentan Cyclohexane Cyclopentane

Mcyclohexane H2O CCl4

158

0 0 0 0 0 -7.72E+04 87.74 8.60E-03 0 0 -8.58E+04 168.6 2.69E-02 0 0 -1.06E+05 264.8 3.25E-02 0 0 -1.28E+05 360.5 3.83E-02 0 0 -1.37E+05 376.4 3.75E-02 0 0 -1.49E+05 457.5 4.44E-02 0 0 -1.57E+05 464 4.34E-02 0 0 -1.69E+05 502.8 3.96E-02 0 0 -1.71E+05 554.2 5.03E-02 0 0 -1.78E+05 563 4.83E-02 0 0 -1.75E+05 562.7 5.04E-02 0 0 -1.89E+05 586.5 4.76E-02 0 0 -1.81E+05 577.8 4.97E-02 0 0 -1.92E+05 650.5 5.64E-02 0 0 -1.99E+05 658.4 5.65E-02 0 0 -1.96E+05 654.3 5.65E-02 0 0 -2.10E+05 685.6 5.64E-02 0 0 -2.03E+05 664.6 5.63E-02 0 0 -2.06E+05 681.9 5.63E-02 0 0 -2.05E+05 678.9 5.63E-02 0 0 -1.93E+05 666.9 5.65E-02 0 0 -2.09E+05 698.1 5.26E-02 0 0 8.15E+04 152.8 2.65E-02 0 0 4.78E+04 238.3 3.19E-02 0 0

-8.05E+04 384.5 4.52E-02 0 0 -1.10E+05 474 4.91E-02 0 0 -1.28E+05 520.3 4.47E-02 0 0 -1.31E+05 571.4 5.48E-02 0 0 -1.60E+05 612.5 4.63E-02 0 0 -2.41E+05 43.41 4.96E-03 0 0 -1.01E+05 145.6 -8.68E-03 0 0

Gibbs Free Energy G = a + b*T + c*T^2 + d*T^3 + e*T^4

a b c d e

Hydrogen Methane Ethane

Propane n-Butane i-Butane

n-Pentane i-Pentane

22-Mpropane n-Hexane

2-Mpentane 3-Mpentane 22-Mbutane 23-Mbutane n-Heptane 2-Mhexane 3-Mhexane

22-Mpentane 23-Mpentane 24-Mpentane 33-Mpentane 3-Epentane

223-Mbutane Benzene Toluene

Cyclopentane Cyclopentane Cyclohexane Ecyclopentane

Mcyclohexane H2O CCl4

159

-49.68 13.84 3.00E-04 3.46E-07 -9.71E-11

-12.98 2.365 -2.13E-03 5.66E-06 -3.73E-09

-1.768 1.143 -3.24E-04 4.24E-06 -3.39E-09

39.49 0.395 2.11E-03 3.97E-07 -6.67E-10

67.72 8.54E-03 3.28E-03 -1.11E-06 1.77E-10

30.9 0.1533 2.64E-03 7.27E-08 -7.28E-10

63.2 -1.17E-02 3.32E-03 -1.17E-06 2.00E-10

64.25 -0.1318 3.54E-03 -1.33E-06 2.51E-10

0 -2.20E-02 3.29E-03 -8.71E-07 -9.07E-11

74.51 -9.67E-02 3.48E-03 -1.32E-06 2.52E-10

111.5 -0.6057 4.92E-03 -3.02E-06 1.07E-09

83.82 -0.1695 3.68E-03 -1.56E-06 3.54E-10

0 -0.193 3.65E-03 -2.42E-06 6.44E-10

0 -0.1695 3.57E-03 -2.35E-06 6.41E-10

71.41 -9.69E-02 3.47E-03 -1.33E-06 2.56E-10

47.74 -0.125 3.60E-03 -1.28E-06 9.86E-11

1.96E-08 -5.61E-02 3.38E-03 -1.21E-06 1.85E-10

77.69 0.2155 2.82E-03 -6.68E-07 0

80.01 0.158 2.83E-03 -6.76E-07 0

75.92 0.2227 2.82E-03 -6.68E-07 0

82.69 0.1556 2.83E-03 -6.75E-07 0

78.61 0.1546 2.83E-03 -6.77E-07 0

86.02 0.1548 2.83E-03 -6.74E-07 0

84.47 -0.5133 3.25E-03 -1.54E-06 3.65E-10

74.16 -0.4231 3.18E-03 -1.44E-06 3.27E-10

1.56E-08 -0.7645 3.87E-03 -1.44E-06 2.31E-10

127.2 -0.6841 4.01E-03 -1.68E-06 3.58E-10

4.56E-09 -0.6481 3.63E-03 -9.99E-07 3.92E-11

64.92 -0.677 4.22E-03 -2.12E-06 7.00E-10

107.6 -0.7046 4.10E-03 -1.53E-06 1.83E-10

-5.73 1.915 -3.96E-04 8.76E-07 -4.95E-10

0 0.2649 6.67E-04 -4.92E-07 1.44E-10

Enthalpy H = a + b*T + c*T^2 + d*T^3 + e*T^4

a b c d e

Hydrogen

Methane

Ethane

Propane

n-Butane

i-Butane

n-Pentane

i-Pentane

22-Mpropane

n-Hexane

2-Mpentane

3-Mpentane

22-Mbutane

23-Mbutane

n-Heptane

2-Mhexane

3-Mhexane

22-Mpentane

23-Mpentane

24-Mpentane

33-Mpentane

3-Epentane

223-Mbutane

Benzene

Toluene

Cyclopentane

Mcyclopentane Cyclohexane

Ecyclopentane

Mcyclohexane

H2O

160

27.143 9.27E-03 -1.38E-05 7.65E-09

19.251 5.21E-02 1.20E-05 -1.13E-08

5.409 1.78E-01 -6.94E-05 8.71E-09

-4.224 3.06E-01 -1.59E-04 3.21E-08

9.487 3.31E-01 -1.11E-04 -2.82E-09

-3.626 4.87E-01 -2.58E-04 5.30E-08

-4.413 5.82E-01 -3.119E-04 6.49E-08

-5.146 6.76E-01 -3.65E-04 7.66E-08

-1.39 3.85E-01 -1.85E-04 2.90E-08

-9.525 5.07E-01 -2.73E-04 5.72E-08

-10.57 6.18E-01 -3.57E-04 8.08E-08

-2.386 5.69E-01 -2.87E-04 5.03E-08

-16.634 6.29E-01 -3.48E-04 6.85E-08

-14.608 6.15E-01 -3.38E-04 6.82E-08

-39.389 8.64E-01 -6.29E-04 1.84E-07

-7.046 6.84E-01 -3.73E-04 7.83E-08

-50.099 8.96E-01 -6.36E-04 1.74E-07

-7.046 7.05E-02 -3.73E-04 7.83E-08

-7.046 6.84E-01 -3.73E-04 7.83E-08

-7.046 6.84E-01 -3.73E-04 7.83E-08

-7.046 6.84E-01 -3.73E-04 7.83E-08

-33.917 4.74E-01 -3.02E-04 7.13E-08

-24.355 5.12E-01 -2.77E-04 4.91E-08

-53.625 5.43E-01 -3.03E-04 6.49E-08

-50.108 6.38E-01 -3.64E-04 8.01E-08

-54.541 6.11E-01 -2.52E-04 1.32E-08

-61.919 7.84E-01 -4.44E-04 9.37E-08

-55.312 7.51E-01 -4.40E-04 1.00E-07

-22.944 7.52E-01 -4.42E-04 1.00E-07

Heat Capacity (Gas) CpG

CpG = a + b*T + c*T^2 + d*T^3

a b c d

Hydrogen

Methane

Ethane

Propane

n-Butane

n-Pentane

n-Hexane

n-Heptane

i-Butane

i-Pentane

2-Mpentane

3-Mpentane

22-Mbutane

23-Mbutane

2-Mhexane

3-Mhexane

22-Mpentane

23-Mpentane

24-Mpentane

33-Mpentane

3-Epentane

Benzene

Toluene

Cyclopentane

Mcyclopentane

Cyclohexane

Ecyclopentane

Mcyclohexane

223-Mbutane

161

15.84 -0.8189 4.87E-02 0 0

370.4 -11.3 0.1483 -8.55E-04 1.86E-06

143.4 -2.118 2.15E-02 -9.35E-05 1.52E-07

124.03 -1.0717 1.01E-02 -3.84E-05 5.57E-08

319.19 -3.5845 2.26E-02 -6.07E-05 6.28E-08

164.2199 -0.3209 1.11E-03

198.2 -0.3866 1.26E-03

218.5 -0.2968 1.06E-03

172.37 -1.7839 1.48E-02 -4.79E-05 5.81E-08

108.3 0.146 -2.92E-04 1.51E-06

142.22 -4.78E-02 7.39E-04

140.49 -3.48E-02 6.81E-04

125.45 3.54E-02 5.96E-04

129.45 1.85E-02 6.08E-04

174.01 -0.10578 9.05E-04

157.94 -4.40E-03 7.10E-04

133.57 0.1093999 6.19E-04

146.42 5.92E-02 6.04E-04

133.5 0.1278 5.92E-04

156.03 -5.28E-02 8.34E-04

148.02 6.39E-02 5.91E-04 -2.72E-17 3.61E-20

129.44 -0.1695 6.48E-04

140.1399 -0.1523 6.95E-04 3.98E-20 -3.47E-23

122.53 -0.4038 1.73E-03 -1.10E-06

155.92 -0.4899999 2.14E-03 -1.56E-06

-220.6 3.1183 -9.42E-03 1.07E-05 9.34E-22

178.52 -0.51835 2.33E-03 -1.68E-06 1.17E-22

131.34 -6.31E-02 8.13E-04

88.446 0.40272 5.62E-05

276.37 -2.0901 8.13E-03 -1.41E-05 9.37E-09

Heat Capacity (Liquid) CpL

CpL = a + b*T + c*T^2 + d*T^3 +e*T^4

a b c d e

Hydrogen

Methane

Ethane

Propane

n-Butane

n-Pentane

n-Hexane

n-Heptane

i-Butane

i-Pentane

2-Mpentane

3-Mpentane

22-Mbutane

23-Mbutane

2-Mhexane

3-Mhexane

22-Mpentane

23-Mpentane

24-Mpentane

33-Mpentane

3-Epentane

Benzene

Toluene

Cyclopentane

Mcyclopentane

Cyclohexane

Ecyclopentane

Mcyclohexane

223-Mbutane

H2O

162

Tem

era

ture

C

Tem

era

ture

Ka

bc

G n

C4

a b

cG

iC4

∆G

ln K

KX

X %

100

373

-1.2

8E+0

53.

60E+

023.

83E-

021.

14E+

04-1

.37E

+05

3.76

E+02

3.75

E-02

8.82

E+03

-2.5

9E+0

30.

8351

442.

3051

450.

6974

4169

.744

14

110

383

-1.2

8E+0

53.

60E+

023.

83E-

021.

53E+

04-1

.37E

+05

3.76

E+02

3.75

E-02

1.29

E+04

-2.4

4E+0

30.

7650

842.

1491

760.

6824

5768

.245

66

120

393

-1.2

8E+0

53.

60E+

023.

83E-

021.

92E+

04-1

.37E

+05

3.76

E+02

3.75

E-02

1.69

E+04

-2.2

8E+0

30.

6986

372.

0110

10.

6678

8666

.788

55

130

403

-1.2

8E+0

53.

60E+

023.

83E-

022.

31E+

04-1

.37E

+05

3.76

E+02

3.75

E-02

2.10

E+04

-2.1

3E+0

30.

6355

331.

8880

270.

6537

4365

.374

29

140

413

-1.2

8E+0

53.

60E+

023.

83E-

022.

70E+

04-1

.37E

+05

3.76

E+02

3.75

E-02

2.51

E+04

-1.9

8E+0

30.

5755

281.

7780

70.

6400

3864

.003

78

150

423

-1.2

8E+0

53.

60E+

023.

83E-

023.

10E+

04-1

.37E

+05

3.76

E+02

3.75

E-02

2.91

E+04

-1.8

2E+0

30.

5184

041.

6793

460.

6267

7562

.677

45

160

433

-1.2

8E+0

53.

60E+

023.

83E-

023.

49E+

04-1

.37E

+05

3.76

E+02

3.75

E-02

3.32

E+04

-1.6

7E+0

30.

4639

611.

5903

610.

6139

5361

.395

34

170

443

-1.2

8E+0

53.

60E+

023.

83E-

023.

88E+

04-1

.37E

+05

3.76

E+02

3.75

E-02

3.73

E+04

-1.5

2E+0

30.

4120

171.

5098

60.

6015

7160

.157

13

180

453

-1.2

8E+0

53.

60E+

023.

83E-

024.

28E+

04-1

.37E

+05

3.76

E+02

3.75

E-02

4.14

E+04

-1.3

6E+0

30.

3624

061.

4367

820.

5896

2358

.962

28

190

463

-1.2

8E+0

53.

60E+

023.

83E-

024.

67E+

04-1

.37E

+05

3.76

E+02

3.75

E-02

4.55

E+04

-1.2

1E+0

30.

3149

781.

3702

290.

5781

57.8

0999

200

473

-1.2

8E+0

53.

60E+

023.

83E-

025.

07E+

04-1

.37E

+05

3.76

E+02

3.75

E-02

4.96

E+04

-1.0

6E+0

30.

2695

941.

3094

330.

5669

9356

.699

32

iC4/

nC

4

APPENDIX C

163

iC5/nC5

Temperature C

Temperature

K

a

b

c

G nC5

a

b

c

G iC5

∆G

ln K

K

X

X %

100 373 -1.49E+05 4.57E+02 4.44E-02 2.77E+04 -1.57E+05 4.64E+02 4.34E-02 2.17E+04 -6.01E+03 1.938594 6.948976 0.874198 87.41976 110 383 -1.49E+05 4.57E+02 4.44E-02 3.26E+04 -1.57E+05 4.64E+02 4.34E-02 2.66E+04 -5.95E+03 1.869926 6.487819 0.86645 86.64498 120 393 -1.49E+05 4.57E+02 4.44E-02 3.75E+04 -1.57E+05 4.64E+02 4.34E-02 3.16E+04 -5.90E+03 1.804815 6.078845 0.858734 85.8734 130 403 -1.49E+05 4.57E+02 4.44E-02 4.24E+04 -1.57E+05 4.64E+02 4.34E-02 3.66E+04 -5.84E+03 1.742994 5.714428 0.851067 85.1067 140 413 -1.49E+05 4.57E+02 4.44E-02 4.74E+04 -1.57E+05 4.64E+02 4.34E-02 4.16E+04 -5.78E+03 1.684226 5.38828 0.843463 84.34633 150 423 -1.49E+05 4.57E+02 4.44E-02 5.23E+04 -1.57E+05 4.64E+02 4.34E-02 4.66E+04 -5.73E+03 1.628294 5.095175 0.835936 83.59358 160 433 -1.49E+05 4.57E+02 4.44E-02 5.73E+04 -1.57E+05 4.64E+02 4.34E-02 5.16E+04 -5.67E+03 1.575001 4.830747 0.828495 82.84954 170 443 -1.49E+05 4.57E+02 4.44E-02 6.22E+04 -1.57E+05 4.64E+02 4.34E-02 5.66E+04 -5.61E+03 1.524169 4.591326 0.821152 82.11515 180 453 -1.49E+05 4.57E+02 4.44E-02 6.72E+04 -1.57E+05 4.64E+02 4.34E-02 6.17E+04 -5.56E+03 1.475634 4.373809 0.813912 81.39123 190 463 -1.49E+05 4.57E+02 4.44E-02 7.22E+04 -1.57E+05 4.64E+02 4.34E-02 6.67E+04 -5.50E+03 1.429249 4.17556 0.806784 80.67842 200 473 -1.49E+05 4.57E+02 4.44E-02 7.72E+04 -1.57E+05 4.64E+02 4.34E-02 7.17E+04 -5.45E+03 1.384875 3.994328 0.799773 79.97728

164

2MP/nC6 Temperature

C

Temperature K

a

b

c

G nC6

a

b

c

G 2MP

∆G

ln K

K

X

X %


3MP/nC6 Temperature

C

Temperature K

a

b

c

G nC6

a

b

c

G 3MP

∆G

ln K

K

X

X %


165

22DMB/nC6 Temperature

C

Temperature K

a

b

c

G nC6

a

b

c

G 22DMB

∆G

ln K

K

X

X %


23DMB/nC6 Temperature

C

Temperature K

a

b

c

G nC6

a

b

c

G 23DMB

∆G

ln K

K

X

X %


166

2MH/nC7

Temperature

e C

Temperature

K

a

b

c

G nC7

a

b

c

G 2MH

∆G

ln K

K

X

X %


3MH/nC7 Temperature

e C

Temperature

K

a

b

c

G nC7

a

b

c

G 3MH

∆G

ln K

K

X

X %


167

22DMP/nC7 Temperature

e C

Temperature

K

a

b

c

G nC7

a

b

c

G 22DMP

∆G

ln K

K

X

X %



e C

Temperature

K

a

b

c

G nC7

a

b

c

G 23DMP

∆G

ln K

K

X

X %


168


e C

Temperature

K

a

b

c

G nC7

a

b

c

G 24DMP

∆G

ln K

K

X

X %

100 373 -1.92E+05 6.51E+02 5.64E-02 5.90E+04 -2.06E+05 6.82E+02 5.63E-02 5.64E+04 -2.54E+03 0.820507 2.271651 0.694344 69.43439 110 383 -1.92E+05 6.51E+02 5.64E-02 6.59E+04 -2.06E+05 6.82E+02 5.63E-02 6.37E+04 -2.23E+03 0.700839 2.015443 0.668374 66.83738 120 393 -1.92E+05 6.51E+02 5.64E-02 7.29E+04 -2.06E+05 6.82E+02 5.63E-02 7.09E+04 -1.92E+03 0.587269 1.799068 0.642738 64.27382 130 403 -1.92E+05 6.51E+02 5.64E-02 7.98E+04 -2.06E+05 6.82E+02 5.63E-02 7.82E+04 -1.61E+03 0.479341 1.615009 0.617592 61.75922 140 413 -1.92E+05 6.51E+02 5.64E-02 8.68E+04 -2.06E+05 6.82E+02 5.63E-02 8.55E+04 -1.29E+03 0.376646 1.457388 0.593064 59.30639 150 423 -1.92E+05 6.51E+02 5.64E-02 9.37E+04 -2.06E+05 6.82E+02 5.63E-02 9.28E+04 -9.81E+02 0.278813 1.321561 0.569255 56.92553 160 433 -1.92E+05 6.51E+02 5.64E-02 1.01E+05 -2.06E+05 6.82E+02 5.63E-02 1.00E+05 -6.68E+02 0.185506 1.203827 0.546244 54.62438 170 443 -1.92E+05 6.51E+02 5.64E-02 1.08E+05 -2.06E+05 6.82E+02 5.63E-02 1.07E+05 -3.55E+02 0.096416 1.101218 0.524085 52.40855 180 453 -1.92E+05 6.51E+02 5.64E-02 1.15E+05 -2.06E+05 6.82E+02 5.63E-02 1.15E+05 -4.24E+01 0.011267 1.01133 0.502817 50.28166 190 463 -1.92E+05 6.51E+02 5.64E-02 1.22E+05 -2.06E+05 6.82E+02 5.63E-02 1.22E+05 2.70E+02 -0.0702 0.932208 0.482457 48.24574 200 473 -1.92E+05 6.51E+02 5.64E-02 1.29E+05 -2.06E+05 6.82E+02 5.63E-02 1.29E+05 5.83E+02 -0.14821 0.862246 0.463014 46.3014


e C

Temperature

K

a

b

c

G nC7

a

b

c

G 33DMP

∆G

ln K

K

X

X %


169

2EP/nC7 Temperature

e C

Temperature

K

a

b

c

G nC7

a

b

c

G 2EP

∆G

ln K

K

X

X %

100 373 -1.92E+05 6.51E+02 5.64E-02 5.90E+04 -1.93E+05 6.67E+02 5.64E-02 6.32E+04 4.25E+03 -1.37008 0.254086 0.202606 20.26065 110 383 -1.92E+05 6.51E+02 5.64E-02 6.59E+04 -1.93E+05 6.67E+02 5.64E-02 7.03E+04 4.41E+03 -1.38566 0.250157 0.200101 20.01007 120 393 -1.92E+05 6.51E+02 5.64E-02 7.29E+04 -1.93E+05 6.67E+02 5.64E-02 7.74E+04 4.58E+03 -1.40045 0.246485 0.197744 19.7744 130 403 -1.92E+05 6.51E+02 5.64E-02 7.98E+04 -1.93E+05 6.67E+02 5.64E-02 8.45E+04 4.74E+03 -1.41451 0.243045 0.195524 19.55236 140 413 -1.92E+05 6.51E+02 5.64E-02 8.68E+04 -1.93E+05 6.67E+02 5.64E-02 9.17E+04 4.90E+03 -1.42789 0.239815 0.193428 19.34282 150 423 -1.92E+05 6.51E+02 5.64E-02 9.37E+04 -1.93E+05 6.67E+02 5.64E-02 9.88E+04 5.07E+03 -1.44063 0.236779 0.191448 19.14478 160 433 -1.92E+05 6.51E+02 5.64E-02 1.01E+05 -1.93E+05 6.67E+02 5.64E-02 1.06E+05 5.23E+03 -1.45279 0.233918 0.189573 18.95733 170 443 -1.92E+05 6.51E+02 5.64E-02 1.08E+05 -1.93E+05 6.67E+02 5.64E-02 1.13E+05 5.39E+03 -1.46439 0.231219 0.187796 18.77965 180 453 -1.92E+05 6.51E+02 5.64E-02 1.15E+05 -1.93E+05 6.67E+02 5.64E-02 1.20E+05 5.56E+03 -1.47549 0.228667 0.18611 18.61101 190 463 -1.92E+05 6.51E+02 5.64E-02 1.22E+05 -1.93E+05 6.67E+02 5.64E-02 1.27E+05 5.72E+03 -1.4861 0.226253 0.184507 18.45074 200 473 -1.92E+05 6.51E+02 5.64E-02 1.29E+05 -1.93E+05 6.67E+02 5.64E-02 1.35E+05 5.88E+03 -1.49627 0.223964 0.182983 18.29825

170

Figure 3.1 C5 paraffin equilibrium plot

Equilibrium Curve

171

Iso-pentane equilibrium curve

2-2Dimethyl butane Equilibrium curve

172

APPENDIX D

Typical Baffles clearances and Tolerances

Shell Bundle Clearance

173

Tube side heat transfer Factor

174

Tube side friction factor

175

Shell side heat transfer factor, for segmental baffles

176

Shell side friction Factor, for segmental baffles

177

Temperature Correction factor: Two shell passes, four or multiple of four tube passes

Temperature Correction factor: One shell passes, two or even tube passes

178

Typical Overall Coefficients

179

Designing Algorithm for Heat Exchanger

180

Discharge Coefficient sieve plate

181

Pump selection guide

182

Pipe Friction verse Reynolds number and relative roughness

184

Compressor operating range

isomerization of light naphtha full and final

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