ChemPlantDesign-Intro to Plant Design Economics

7/28/2019 ChemPlantDesign-Intro to Plant Design Economics

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CBB 3024

PROCESS PLANT DESIGN

Lecturer : Assoc. Prof. Dr. Mohamed Ibrahim Abdul MutalibDr Balasubramanian Periyasamy

4 Credit-Hour Core Course

Lecture Time : Mon 10 am 12 noon ; Tues 10 am 12 noon

: Thurs 10 am 12 noon ; Fri 8 10 am

Location : 21-01-04 ; 01-02-02

LT C6 21-02-07

Semester May 2011


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PROGRAMME OUTCOMES UTP CHEMICAL ENGINEERING

1 Acquire and apply knowledge of basic sciences and engineering fundamentals

2Acquire and apply Chemical Engineering principles and in-depth technical

knowledge

3 Ability to design, optimize and operate processes

4Undertake problem identification, formulation and solution by considering the

concept of sustainable development

5Comprehend social, cultural, global and environmental responsibilities of a

professional engineer, and the need for sustainable development

6 Communicate effectively in a professional context

7 Exhibit professional and ethical responsibilities

8 Demonstrate leadership, business acumen and entrepreneurship

9 Demonstrate the capability to undertake lifelong learning


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COURSE OUTCOMES CHEMICAL PLANT DESIGN

K S A

3 PO1 PO2 PO3 PO4 PO5 PO6 PO7 PO8 PO3 PO9 PO7

CO1

Integrate knowledge from previous

chemical engineering courses in designing

a chemical process systemx x x

CO2

Apply conceptual process design and

synthesis tools in designing a chemical

process systemx x

CO3Apply a systematic approach or method to

design a chemical process systemx x

K Knowledge

S Skill

A

Attitude


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Course Content, Delivery & Assessment

Lec.

No.

Topic Assessment Lecturer

1-2

3-4

Introduction to Plant Design and Economics (Approaches andStages of Process Design)

General Plant Consideration (Plant Layout/Utility System)

Quiz 1

Dr Ibrahim

Dr Ibrahim

5-8 Synthesis of Reactor Separation System

(Fundamentals and Selection of Reaction System &

Separation System)

Assign 1

Test 1

Dr Ibrahim

9-12 Synthesis of Reactor Separation System(Fundamentals and Selection of Reaction System &

Separation System)

Assign 1Quiz 2

Test 1

Dr Ibrahim

13-16 Synthesis of Reactor Separation System

(Process Recycle and Distillation Sequencing)

Assign 1

Test 1

Dr Ibrahim

17-20 Heat Integration (Composite Curve & Heat Recovery Pinch,

Problem Table Algorithm)

Assign 2

Test 1

Dr Ibrahim

21-24 Heat Integration (Grand Composite Curve & Multiple Utilities) Assign 2

Test 1

Dr Ibrahim

25-28 Heat Integration (HEN Design) Assign 2

Test 1

Dr Ibrahim


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Lec.

No.

Topic Assessment Lecturer

29-32 Process Flowsheeting (Flowsheet Synthesis & Simulation,

Model Formulation, Solution Strategies)

Test 2 Dr Bala

33-36 Economics of Chemical Plants Quiz 3 Dr Bala

37-40 Equipment Design & Specification (Material Transfer &

Handling, Mass Transfer Equipment)

Assign 3

Test 2

Dr Bala

41-44 Equipment Design & Specification (Mass Transfer & Reactor

Equipment)

Assign 3

Test 2

Dr Bala

45-48 Equipment Design & Specification (Pressure Vessel Design) Assign 3

Test 2

Dr Bala

49-52 Environmental Studies & Consideration Effluent Treatment,

Waste Minimisation and Life Cycle Analysis

Quiz 4 Dr Bala

53-56 Plant Wide Control (Material & Quality Control, Pairing of

Variables in MIMOS, Typical Unit Operation and ControlStrategies)

Quiz 4 Dr Bala

Assessment : Quizzes 4 (5 %) Assignments - 3 (5%) Project - 1 (10%)

Tests - 2 (20%) Final Exam - 1 (60%)


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The purpose of engineering is to create material wealth Douglas, Conceptual Design of Chemical

Processes 1988.

How to do so ?

WHAT CAN YOU SAY ABOUT THE CHEMICAL PROCESS ?

Lecture 1. Introduction to Plant Design and Economics

Raw Materials

+ Other Feeds

Energy

In

CHEMICAL

PROCESS Products + Wastes

EnergyOut

In a chemical process, the transformation of raw materials into desired products usually cannot beachieved in a single step. Instead, the overall transformation is broken down into a number of stepsthat provide intermediate transformations. (Robin Smith, Chemical Process Design 1995)

The goal of the engineer is to design and produce artifacts and systems that are beneficial to mankind

Biegler, Grossman & Westerberg, Systematic Methods of Chemical Process Design 1997.


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Raw Materials

+ Other Feeds

Energy

CHEMICAL

PROCESSProducts + Wastes

Energy

SO, A NUMBER OF PROCESSING STEPS MADE UP THE CHEMICAL PROCESS.

QUESTIONS?

- WHAT SORT OF PROCESSINGS ARE LOCATED IN THE CHEMICAL PROCESS?

- HOW DO WE SEQUENCE THE PROCESSING STEPS?

- TO WHAT EXTEND CAN WE EXPECT EACH OF THE PROCESSING STEP TO

PERFORM AND WHAT FEATURES ARE REQUIRED?

- HOW MUCH ENERGY IS REQUIRED AND HOW MUCH IS PRODUCED?

- HOW MUCH FEEDS DO WE NEED AND HOW MUCH PRODUCTS ARE PRODUCED?

- HOW MUCH WASTES ARE GENERATED?

- HOW MUCH PROFIT COULD BE DERIVED?

HOW DO WE ADDRESS

THIS?

Concept Design for Chemical Process


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Raw Materials

+ Other Feeds

Energy

CHEMICAL

PROCESS

Products + Wastes

Energy

PROCESS PLANT DESIGN IS THE NAME OF THE GAME HERE !

LITTLE OR LIMITED

INFORMATIONS ARE

AVAILABLE

But so many possibilities

or solutions !

BEFORE COMING UP WITH A

COMPLETE PROCESS

Perhaps, the major features that distinguishes design problems from other types of engineeringproblems is that they are under defined; i.e., only a very small fraction of the information neededto define a design problem is available from the problem statement.(Douglas, Conceptual Design of Chemical Processes 1988)


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Once the process concept has been designed which produces process flowsheet,

the equipment design then has to be performed..

Distillation


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The equipment design comprises of ;

1. Performance/Capacity Rating or Sizing

2. Vessel Mechanical Design

Equipments Dimensions

diameter & height

No. of stages

for contact

Heat Transfer

Area Needed

Wall thickness

Support Design

Pipe fittings &

Reinforcement

Internal Design
http://www.google.com.my/imgres?imgurl=http://www.alaquainc.com/images/Heat_E18.gif&imgrefurl=http://www.alaquainc.com/Heat_Exchangers.aspx&usg=__fKlKYnfYHumFQKnRm3VlxrKyt2Q=&h=350&w=469&sz=10&hl=en&start=2&zoom=1&itbs=1&tbnid=5QyxSzXc1123xM:&tbnh=96&tbnw=128&prev=/images?q=Heat+Exchanger&hl=en&sa=G&ndsp=18&tbm=isch&ei=KGuiTdShDJTRcJetiPAB


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The process safety and control strategy has to be devised;

1. Process Safety

2. Process Control Strategy

- Material Control

- Product Control

Overall Plant and Equipment .

- Hazard and Operability Study (HAZOP)

- Risk Assessment

HAZOP study

Risk Assessment

Matrix


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And Waste Treatment/Minimisation need to also be addressed

1. Waste Treatment (conventional)

2. Waste Minimisation (sustainability)

- Suitable end of pipe treatment on the effluent (gases & liquids)

- Adjusting processes to minimise the generation of waste

REACTOR

SEPARATION

& RECYCLE

SYSTEM

HEAT EXCHANGER

NETWORK

UTILITIES


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In finalising the process and equipment design, several stages of economic analysiscould be conducted

First step;EP 1 = Revenue Cost of Raw Material

Second Step (after mass balance developed)

EP 2 = Revenue Cost of Raw Material - Utility

Third Step (after equipments designed)EP 3 = Revenue Cost of Raw Material Utility Annualised Cost of Equipment

The economics analysis continues with other costs (manpower, insurance etc) .

with profitability analysis conducted at the end to assess project viability

Pay back time,

Return on InvestmentInternal Rate of Return


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Finally ..


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FEED REACTOR

CW

STEAM

PRODUCT 1

PRODUCT 2

1. ADDRESS THE INDIVIDUAL

PROCESS/TRANSFORMATION STEP

RECYCLE

2. ADDRESS THE REQUIRED

INTERCONNECTION BETWEEN THE STEPS

Lecture 2.Approaches and Stages of Process Plant Design

In the first stage, conceptual process design has to be conducted.In general conceptual process design has to address two major activities .


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.and the target is to create the best possible feasible flowsheet for the process.

THIS IS WHAT YOU WANT

AT THE END OF THE STAGE !

WHAT OTHER INFORMATIONS SHOULD BE

AVAILABLE IN A FLOWSHEET ?

AND HOW DO YOU GET SUCH INFORMATION ?

FEED REACTOR

CW

STEAM

PRODUCT 1

PRODUCT 2

RECYCLE

Str1 Str2 Str3 Str4 Str5 Str6 Str7 Str8 Str9

F

T

P

x

H

DEFINITION OF A FLOWSHEET.

FLOWSHEET IS A DIAGRAMMATIC REPRESENTATION OF THE PROCESSSTEPS AND ITS INTERCONNECTIONS.


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A SYSTEMATIC APPROACH OR METHOD IS REQUIRED

However, as much as we would like to have a systematic approach or method, we must alsorecognised that process design is an art !

If we reflect on the nature of process synthesis and analysis, . , we recognize that process designactually is an art, i.e., creative process. (Douglas, Conceptual Design of Chemical Processes 1988)

The approach or method should be able to help in addressing these questions

Why is the unit operation selected ?How are the unit operations connected ?

What are the utilities required and approximate amount ?

How will it be supplied to the process unit operations ?

What wastes will be generated?


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1. ADDRESS THE INDIVIDUALPROCESS/TRANSFORMATION STEP

2. ADDRESS THE REQUIRED

INTERCONNECTION BETWEEN THE STEPS

FEED REACTOR

CW

STEAM

PRODUCT 1

PRODUCT 2

RECYCLE

FLOWSHEET

Now, what criteriashould be adopted besides economics during the design activities?

MINIMISE COST

MINIMISE ENERGY CONSUMPTION

MINIMISE WASTES GENERATION

..... BUT HOW TO

OPTIMISE ?

HIGH SAFETY & INTEGRITY

GOOD OPERATIONAL ASPECTS

QUANTIFIABLE

FACTOR !

NON - QUANTIFIABLE

FACTOR !VERSUS


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FEED REACTOR

CW

STEAM

PRODUCT 1

PRODUCT 2

RECYCLE

Consider back the flowsheet !

OPTIMISING THE INTERCONNECTIONSBETWEEN THE UNITS/STEPS IN THE PROCESS

?

MANY POSSIBLE CONNECTIONS WHICH LEAD

TO DIFFERENT STRUCTURES OF FLOWSHEET

THUS DIFFERENT ECONOMIC IMPACT EVEN TO THE

EXTENT OF THE INDIVIDUAL UNIT ITSELF!

DIS-CONTINUOUS FUNCTION

STRUCTURAL OPTIMISATION

OPTIMISING A SINGLE UNIT/STEP

IN THE PROCESS

EG. DISTILLATION COLUMN

TOTAL

COST

RR

RR --> ENERGY

RR --> CAPITAL

CONTINUOUS FUNCTION

PARAMETER OPTIMISATION

How do we tackle them ?


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Consider the approaches/methods which have been introduced to deal with such complex optimisation ?

MIXED INTEGER LINEAR/

NON-LINEAR PROGRAMMING

MATHEMATICAL METHOD

USE A MATHEMATICAL PROGRAMMING METHOD TO

SOLVE AND GIVE SOLUTION FOR THE PROCESS.

SIMULTANEOUS SOLUTION OF ALL THE SYSTEM.

CONCEPT IS BASED ON

"CREATING AND OPTIMISING A REDUCIBLE

STRUCTURE"

DECISION ARE BASED ON SOLELY MATHEMATICALOPTIMISATION CRITERIA

Grossman I. E, Comp. Chem. Eng., 9: 463, 1985

Biegler, Grossman & Westerberg, Systematic

Method of Chemical Process Design 1997

ONION MODEL

HEURISTIC METHOD

USE A SEQUENTIAL/HIERARCHICAL METHOD

ACCORDING TO FOLLOWING SEQUENCE ;

1. REACTOR

2. SEPARATION AND RECYCLE SYSTEM

3. HEAT EXCHANGER NETWORK

4. UTILITIES

CONCEPT IS BASED ON

"BUILDING AN IRREDUCIBLE STRUCTURE"

DECISION ARE BASED ON ENGINEERING GUIDELINES

ESTABLISHED AND MATHEMATICAL OPTIMISATION

Smith R.,Chemical Process Design 1995

HIERARCHICAL APPROACH

USE A SEQUENTIAL/HIERARCHICAL METHOD

ACCORDING TO FOLLOWING SEQUENCE ;

1. BATCH VS CONTINUOUS

2. INPUT-OUTPUT STRUCTURE OF THE FLOWSHEET

3. RECYCLE STRUCTURE OF THE FLOWSHEET

4. GENERAL STRUCTURE OF SEPARATION SYSTEM

5. HEAT EXCHANGER NETWORK Douglas.,Conceptual Design of Chemical Process 1988


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HEURISTIC METHOD The Onion Model

REACTOR

SEPARATION

& RECYCLE

SYSTEM

HEAT EXCHANGER

NETWORK

UTILITIES

- FOLLOWS ONION LOGIC

Design starts from the centre ( heart of process ) which is the reactor.

At each layer, decision has to be made to complete the design

requirement for the stage. As such, many best local optimal decisions

are made since the whole picture is incomplete. Unit/Equipment is

added only if it is economically justified based on the current available

information. This keeps the process (structure) irreducible and features

which are technically/economically redundant are not included.

What do you see are the advantages and disadvantages of this method ?

Advantages Disadvantages


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WHAT DO YOU NOTICE ON

THE STATEMENT CONTAIN WITHIN

THE SHADED BOX ?

Compare these statements

to the onion model !

REACTOR

SEPARATION

& RECYCLE

SYSTEM

HEAT EXCHANGER

NETWORK

UTILITIES

HEURISTIC METHOD The Hierarchical Approach

The conceptual design is performed based on 5 different stages. The approach is somewhat

different by tackling the 5 different level that are classified differently. The 5 levels are ;

Level 1 Decision : Batch vs Continuous

Level 2 Decision : Fixing the Input-Output Structure

Level 3 Decision : Determining the Recycle Structure for the Process

Level 4 Decision : Determining the Separation System

Level 5 Decision : Determining the Heat Exchanger Network

At each level except level 1, alternatives have to

be generated and assessed to see its economic

and operational potential. Some level of process

design has to be conducted on the

units/process placed at every stages.


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Semester July 2004

MATHEMATICAL METHOD The Mixed Integer Linear/Nonlinear Programming

What are the advantages and disadvantages of this method ?

Advantages Disadvantages

- CREATION OF SUPERSTRUCTURE/HYPERSTRUCTURE

A major (super) structure is created which embedded within it all feasible

process (including its operations) and all feasible interconnections that

are candidates for an optimal design. The method is completely automated

and depends only on the computer programming to solve it. The design

problem is formulated into sets of mathematical equations which has to be

solved by the mathematical programming. Started off with many redundant

features, the programming optimise and reduce the process (structure)

to an optimal solution.

other process

alternatives


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From the conceptual process design, a flowsheet is generated for the process. The next stage

would then be to address the equipment design

FEED REACTOR

CW

STEAM

PRODUCT 1

PRODUCT 2

RECYCLE

Heat Exchanger

Type of Exchanger (Plate / Shell & Tube)

Heat Transfer CoefficientHeat Transfer AreaPressure DropExchanger Configuration

Reactor

Type of ReactorReaction KineticsReaction SelectivityReactor SizingReactor Temperature & Pressure

No of stagesReflux RatioFeed Location

Vapour/Liquid LoadingColumn SizingInternalsColumn Temperature &Pressure

Distillation


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There are established methods for performing the design of these equipments .

Heat Exchanger

Rating calculation that will

enable the sizing of the heat

exchanger to be done

Kerns method Reactor

Reactor

From the kinetics obtained

from experiment, sizing of

reactor could be done based

on residence time.

Distillation

No of stages calculation versus reflux ratio

could be made and the feed location

determined.

Results are then simulated in rigoroussimulation model for actual design involving

capacity calculation for internals.

Fenske, Gilliland & Underwood


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Heat Exchanger

Reactor

Distillation

Given that each of the equipment will normally involved vessel operated at various pressure and

temperature, the design of the pressure vessel has to be conducted. The design is to be done

according to standards..

Pressure Vessel DimensionShell Thickness

Flanges Connection &

Reinforcement

Support type and Design

Corrosion Allowance

Welding specification

American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel Code.

ASME Boiler and Pressure Vessel Code (BPVC) is a standard that

provides rules for the design, fabrication, and inspection of boilers and

pressure vessels. It is reviewed every three years.


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Health, Safety and Environment aspects are increasingly gaining attention in view of their importance.

Therefore the design of process plant has to take into account of the HSE particularly the safety and

environment aspects where it has to be integrated with the design activities .

Inherent SafetyHazard Analysis

FIRE

Auto Ignition temp.

Flammability Limits

Flash Points

Minimum Oxygen concentration

Flammable liquids are more

dangerous than flammable gas

EXPLOSION

Chemical Energy vs

Physical Energy

Deflagration vs detonation

Confined vs Unconfined

Explosions (VCE)

TOXIC RELEASE

Time weighed exposure

Short term Exposure

Ceiling Exposure

LC50 & LD50

DOW Index

Remove or attenuate conditions that

could lead to the 3 incidents such as

high P and T ..

HAZOP

Hazard and

Operability

Study.


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Environment

Health, Safety and Environment aspects are increasingly gaining attention in view of their importance.

Therefore the design of process plant has to take into account of the HSE particularly the safety and

environment aspects where it has to be integrated with the design activities .

Environment

Waste Minimisation(Clean Process Technology)

Reactor

Increase conversion if selectivity is not an issue

Product removal for reversible reaction favoring product

Set T & P to improve selectivity

Distillation

Recycling waste stream to suppress by product reaction

Feed purification

Eliminate use of extraneous material for separation

(entrainer)

Waste stream recovery

Improve heat recovery

Waste Treatment

Air Effluent

Particulate, CO2, CO, SOx, Nox

Gravity Settlers, Inertial Collectors, Scribbers, Filters,

Electrostatic precipitators, catalytic reaction etc.

Water Effluent

Membrane, Adsorption, Absorption, thermal oxidation,

biological treatment, membrane separation etc.


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Finally ..

You will develop the constructiondetails for a process plant .

Documents

ChemPlantDesign-Intro to Plant Design Economics