EP426Chemical Process Design and Optimization

Chapter 1

I like to have a class replacement for EP426.

38 students are agreed to have a replacement class for 10 Feb 2016 (CNY)Based on majority: 23 Jan 2016 (Saturday) is the replacement class

Teaching Plan

Student attainment CLO1: Identify sustainable processes for chemical production.

C4 – Assessing peer feedback and Critical evaluation of literature.

A4 – Case study, PBL, and Case summary.

P1 - Case history exercise and Case presentation.

PLO9 - ENVIRONMENT AND SUSTAINABILITYUnderstand the impact of professional engineering solutions in societal and environmental contexts and demonstrate knowledge of and need for sustainable development.

Note:

Teaching method - Lecture & Group Project

Assessment - Test, Final Exam and report presentation.

EP426Chemical Process Design and Optimization

Chapter 1b – Sustainable Process DesignHierarchical approach to process design

Introduction

Most important decision in the evolution of a process is 1. the choice of which chemical syntheses

2. routes should be investigated

to produce a desired product.

There are at least two viable ways to produce a givenchemical. These alternative routes may require differentraw materials and may produce different by-products.

Evaluating Factors for alternative route

• Cost of the raw materials.

• Value of the by-products.

• Complexity of the synthesis.

• Environmental impact.

Hierarchy of Process Design

It is an approach to a conceptual process design which follows a series of decisions and steps.

These decisions are listed as follows.1. Decide whether the process will be batch or continuous.

2. Identify the input/output structure of the process.

3. Identify and define the recycle structure of the process.

4. Identify and design the general structure of the separation system.

5. Identify and design the heat-exchanger network or process energy recovery system.

Class activity

Form a group of 5 students and describe the step in details on what are the decision should be made. Student should focus on the following

- Concept, Technique, Example

You may use any available literature.

Class will be continued at 1:30 PM

Chin Ka Wing

Lee Qing Zhou

Yimanuell Pillai a/l James Pillai

Tan Pui Yee

Boo Ee-Yern

Lim Chee Hui

Chong Kian Hen

Chee Hwan Lai

Lee Long Ee

Teo Xsu Li

Tan Yee Huan

Ding Joe Aw

Gurinapreet Kaur A/P Rashem Singh

Teh Yoon Wei

Yudhisthira A/L Ramanaidu

Maha Letchumy A/P Gunalan

Khoo Lynn Hui

SULEIMAN AHMED YUSUF

Shaikh Mohamad Jawad

Jannatul Fatihah Binti Izaham

Dashenee A/P Subramaniam

Mirisse Galapathige Nandini

Gitta Fitriani

Loshanya A/P Renugopal

Andrew Arvind A/L Simon

Tey Kai Jing

Chen Jun Ting

Choo Wen Xin

Muhammad Imran Bin Shukri

Kavimanan A/L Munusamy

Arwin A/L P Jayapalan

Ng Ka Nyan

Shadeeshkumar A/L Visanathan

Lew Man Kit

Andrea Lai Jia Xin

Wong Vivian

Ganesh Liew Hock Ling

Helena Francis

Rema Malar A/P Rabinthran

Tan Kuan Leong

Goh Chai Ni

Karanjit Singh

Alex Chan Weng Kit

Thineshwari A/P Manamaran

Tan Jing Khai

Soschorespicko Dimos

Chin Yung Han

Piravena Pricillia A/P Gunusegran

Kheshawarthini A/P Santherasaygargam

Lohan A/L Selvasubramaniam

Chai Wei Fong

Abdul Rahman

Ray Jeevan Sagayam

Soh Wei Ming

Wong Mun Yuan

Ho Lup Fai

Renusha Parameswaran

Christopher

Brian Wijaya

Lai Pun Mun

Anour Adam

Ashley

Group member and Step selection

1

2

3

4 5

1

2

3 4

5

5

4

Step 1 – Batch or Continuous

Continuous

Batch

Fed-batch

Batch-product removal

Decide

Factor between Batch OR Cont.

• Size

• Prod. Quality

• Flexibility

• Product variation

• Efficiency

• Maintenance

• Feedstock

• Demand

• Rate

• Fouling

• Safety

• Controllability

Step 2 - Input/Output Structure

• The purpose of this section is to investigate theinput/output structure of the process.

• The inputs represent feed streams and the outputsare product streams, which may be desired orwaste streams.

1. Process Concept Diagram

2. Structure of the Process Flow Diagram

3. Generic Block Flow Process Diagram

Identify

Process Concept Diagram

Structure of the Process Flow Diagram

Structure of the Process Flow Diagram

NOT at a suitable

concentration,

Temperature, and

pressure for optimal

performance in the

reactor.

Desired product(s), any

unused reactants, and

a variety of undesired

by-products

include gases, liquids, and

solids that must be treated

prior to being discharged

the return of unreacted

feed chemicals for

further reaction

separation of products,

by-products, waste

streams, and unused

feed

to provide the

conditions required

for the effective

separation

Generic Block Flow Process Diagram

Step 3 - Recycle Structure

Efficiency of Raw Material Usagesingle-pass conversion in the reactor, the overall conversion in the process, and the yield.

Unreacted raw materials can be recycled by:• Separate and purify unreacted feed material from

products and then recycle.• Recycle feed and product together and use a purge

stream.• Recycle feed and product together and do not use a

purge stream.

Step 4 - Separation System

The goal of the separator is to

• Produce a product of acceptable purity

• Recycle stream of unreacted feed materials,

• Separate the product stream with streams of by-products.

Ideal separator represents a process of infinite cost.Therefore, one step is to “de-tune” the separation toa reasonable level.

Guidelines for Choosing Separation Units

1. Use distillation as a first choice for separation offluids when purity of both products is required.

2. Use gas absorption to remove one trace componentfrom a gas stream.

3. Consider adsorption to remove trace impurities fromgas or liquid streams.

4. Consider pressure-swing adsorption to purify gasstreams, especially when one of the components hasa cryogenic boiling point.

5. Consider membranes to separate gases of cryogenicboiling point and relatively low flowrates.

6. Choose an alternative to distillation if the boilingpoints are very close or if the heats of vaporizationare very high.

Guidelines for Choosing Separation Units

7. Consider extraction as a choice to purify a liquidfrom another liquid.

8. Use crystallization to separate two solids or to purifya solid from a liquid solution.

9. Use evaporation to concentrate a solution of a solidin a liquid.

10. Use centrifugation to concentrate a solid from aslurry.

11. Use filtration to remove an almost dry solid formfrom a slurry.

12. Use screening to separate solids of different particlesize.

Guidelines for Choosing Separation Units

13. Use float/sink to separate solids of differentdensity from a mixture of pure particles.

14. Consider reverse osmosis to purify a liquid froma solution of dissolved solids.

15. Use leaching to remove a solid from a solidmixture.

16. Consider chromatography for final purification ofhigh-value products (such as proteins) from dilutestreams.

Step 5 - Energy Recovery System

Designing a heat exchanger network that consumesthe minimum amount of utilities and requires theminimum number of exchangers.

Objective: To design an optimum network of heat exchangers,connecting between the hot and cold streams and between thestreams and cold/hot utilities.

What is optimal? - Implies a trade-off between CAPITAL COSTS (Costof equipment) and ENERGY COSTS (Cost of utilities).

Without Heat Integration With Heat Integration

Heat Integration example

Proposed HEN showing interior heat exchanger (1-3) and heat utilities (H,C)

Typical Proposed HEN

Q is multiply by 104 Btu/hr

Proposed HEN showing interior heat exchanger (1-3) and heat utilities (H,C)

Typical Proposed HEN (with pinch analysis)

Q is multiply by 104 Btu/hr

To be continued…Chapter 2 - Synthesis of process flow diagram (PFD).