1. CBB 3024 PROCESS PLANT DESIGN 4 Credit-Hour Core Course Semester May 2011 Lecturer : Assoc. Prof. Dr. Mohamed Ibrahim Abdul Mutalib Dr Mohanad El-Harbawi Lecture Time : Mon 10 am – 12 noon ; Mon 1 – 3 pm : Thurs 11 am – 1 pm ; Fri 8 – 10 am Location : LT D2 ; 21-01-04 17-02-06 21-02-07

2. PROGRAMME OUTCOMES – UTP CHEMICAL ENGINEERING

3. COURSE OUTCOMES – CHEMICAL PLANT DESIGN K – Knowledge S – Skill A – Attitude

4. Course Content, Delivery & Assessment

5. Assessment : Quizzes – 4 (5 %) Assignments - 3 (5%) Projects - 1 (10%) Tests - 2 (20%) Final Exam - 1 (60%)

6. How to do so ? Lecture 1. Introduction to Plant Design and Economics The purpose of engineering is to create material wealth – Douglas, Conceptual Design of Chemical Processes 1988. 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. Energy In CHEMICAL PROCESS Raw Materials + Other Feeds Products + Wastes Energy Out WHAT CAN YOU SAY ABOUT THE CHEMICAL PROCESS ? In a chemical process, the transformation of raw materials into desired products usually cannot be achieved in a single step. Instead, the overall transformation is broken down into a number of steps that provide intermediate transformations. (Robin Smith, Chemical Process Design 1995)

8. Raw Materials + Other Feeds CHEMICAL PROCESS Products + Wastes Energy Energy PROCESS PLANT DESIGN IS THE NAME OF THE GAME HERE ! LITTLE OR LIMITED INFORMATIONS ARE AVAILABLE BEFORE COMING UP WITH A COMPLETE PROCESS But so many possibilities or solutions ! Perhaps, the major features that distinguishes design problems from other types of engineering problems is that they are under defined; i.e., only a very small fraction of the information needed to define a design problem is available from the problem statement. (Douglas, Conceptual Design of Chemical Processes 1988)

9. Once the process concept has been designed which produces process flowsheet, the equipment design then has to be performed….. Distillation

10. The equipment design comprises of ; Performance/Capacity Rating or Sizing Vessel Mechanical Design Equipments’ Dimensions – diameter& height Heat Transfer Area Needed No. of stages for contact Internal Design Wall thickness Pipe fittings & Reinforcement Support Design

13. Product ControlOverall Plant and Equipment ….

16. Finally …..

17. 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 …. 1. ADDRESS THE INDIVIDUAL PROCESS/TRANSFORMATION STEP RECYCLE STEAM FEED REACTOR PRODUCT 1 CW PRODUCT 2 2. ADDRESS THE REQUIRED INTERCONNECTION BETWEEN THE STEPS

18. ……….and the target is to create the best possible feasible flowsheet for the process. DEFINITION OF A FLOWSHEET. FLOWSHEET IS A DIAGRAMMATIC REPRESENTATION OF THE PROCESS STEPS AND ITS INTERCONNECTIONS. RECYCLE STEAM FEED REACTOR PRODUCT 1 CW Str1 Str2 Str3 Str4 Str5 Str6 Str7 Str8 Str9 F T P PRODUCT 2 x H 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 ?

19. A SYSTEMATIC APPROACH OR METHOD IS REQUIRED 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? However, as much as we would like to have a systematic approach or method, we must also recognised that process design is an art ! If we reflect on the nature of process synthesis and analysis, …. , we recognize that process design actually is an art, i.e., creative process. (Douglas, Conceptual Design of Chemical Processes 1988) This course will develop the art to conduct process design !

20. Now, what criteriashould be adopted besides economics during the design activities? 1. ADDRESS THE INDIVIDUAL PROCESS/TRANSFORMATION STEP RECYCLE STEAM FLOWSHEET FEED REACTOR PRODUCT 1 CW PRODUCT 2 2. ADDRESS THE REQUIRED INTERCONNECTION BETWEEN THE STEPS NON - QUANTIFIABLE FACTOR ! QUANTIFIABLE FACTOR ! VERSUS HIGH SAFETY & INTEGRITY MINIMISE COST GOOD OPERATIONAL ASPECTS MINIMISE WASTES GENERATION MINIMISE ENERGY CONSUMPTION ..... BUT HOW TO OPTIMISE ?

21. Consider back the flowsheet ! RECYCLE STEAM FEED REACTOR PRODUCT 1 CW PRODUCT 2 OPTIMISING A SINGLE UNIT/STEP IN THE PROCESS EG. DISTILLATION COLUMN OPTIMISING THE INTERCONNECTIONS BETWEEN 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! RR --> ENERGY TOTAL COST ? RR --> CAPITAL RR DIS-CONTINUOUS FUNCTION CONTINUOUS FUNCTION STRUCTURAL OPTIMISATION PARAMETER OPTIMISATION How do we tackle them ?

22. Consider the approaches/methods which have been introduced to deal with such complex optimisation ? HEURISTIC METHOD MATHEMATICAL METHOD MIXED INTEGER LINEAR/ NON-LINEAR PROGRAMMING ONION MODEL USE A SEQUENTIAL/HIERARCHICAL METHOD ACCORDING TO FOLLOWING SEQUENCE ; 1. REACTOR 2. SEPARATION AND RECYCLE SYSTEM 3. HEAT EXCHANGER NETWORK 4. UTILITIES USE A MATHEMATICAL PROGRAMMING METHOD TO SOLVE AND GIVE SOLUTION FOR THE PROCESS. SIMULTANEOUS SOLUTION OF ALL THE SYSTEM. DECISION ARE BASED ON SOLELY MATHEMATICAL OPTIMISATION CRITERIA DECISION ARE BASED ON ENGINEERING GUIDELINES ESTABLISHED AND MATHEMATICAL OPTIMISATION CONCEPT IS BASED ON "CREATING AND OPTIMISING A REDUCIBLE STRUCTURE" CONCEPT IS BASED ON "BUILDING AN IRREDUCIBLE STRUCTURE" Grossman I. E, Comp. Chem. Eng., 9: 463, 1985 Smith R.,Chemical Process Design 1995 Biegler, Grossman & Westerberg, Systematic Method of Chemical Process Design 1997 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

23. REACTOR SEPARATION & RECYCLE SYSTEM HEAT EXCHANGER NETWORK UTILITIES HEURISTIC METHOD – The Onion Model - 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 ? Disadvantages Advantages

24. 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 WHAT DO YOU NOTICE ON THE STATEMENT CONTAIN WITHIN THE SHADED BOX ? 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. REACTOR SEPARATION & RECYCLE SYSTEM Compare these statements to the onion model ! HEAT EXCHANGER NETWORK UTILITIES

25. Semester July 2004 other process alternatives MATHEMATICAL METHOD – The Mixed Integer Linear/Nonlinear Programming - 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. What are the advantages and disadvantages of this method ? Disadvantages Advantages

26. From the conceptual process design, a flowsheet is generated for the process. The next stage would then be to address the equipment design … RECYCLE STEAM FEED REACTOR PRODUCT 1 CW PRODUCT 2 Heat Exchanger Reactor Distillation No of stages Reflux Ratio Feed Location Vapour/Liquid Loading Column Sizing Internals Column Temperature & Pressure Type of Exchanger (Plate / Shell & Tube) Heat Transfer Coefficient Heat Transfer Area Pressure Drop Exchanger Configuration Type of Reactor Reaction Kinetics Reaction Selectivity Reactor Sizing Reactor Temperature & Pressure

27. There are established methods for performing the design of these equipments …. Reactor Distillation Heat Exchanger Kern’s method Reactor Rating calculation that will enable the sizing of the heat exchanger to be done Fenske, Gilliland & Underwood From the kinetics obtained from experiment, sizing of reactor could be done based on residence time. No of stages calculation versus reflux ratio could be made and the feed location determined. Results are then simulated in rigorous simulation model for actual design involving capacity calculation for internals.

28. 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….. Heat Exchanger Pressure Vessel Dimension Shell Thickness Flanges Connection & Reinforcement Support type and Design Corrosion Allowance Welding specification Reactor Distillation 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.

29. 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 Safety Remove or attenuate conditions that could lead to the 3 incidents such as high P and T ….. Hazard Analysis EXPLOSION TOXIC RELEASE FIRE HAZOP Hazard and Operability Study. Auto Ignition temp. Flammability Limits Flash Points Minimum Oxygen concentration Flammable liquids are more dangerous than flammable gas Chemical Energy vs Physical Energy Deflagration vs detonation Confined vs Unconfined Explosions (VCE) Time weighed exposure Short term Exposure Ceiling Exposure LC50 & LD50 DOW Index

30. 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 Environment Waste Treatment 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 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.

31. Finally ….. You will develop the construction details for a process plant ….