1. Chemical Engineering Plant Design
Lek Wantha
Lecture 01

2. What is Chemical Process?
A chemical process is a process which raw material are transformed or converted into desired product.

3. Strategies for Chemical Product Design
Need
Ideas
Selection
Manufacture

4. Need for Process Design
To produce desired product
To convert a purchased raw material
To convert a waste by-product to a valuable product
To find a new way of producing an existing product
To exploit a new technology

5. What is a process design?
Process design establishes the sequence of chemical and physical operations; operating conditions; the duties; major specifications and materials of construction of all process equipment; the general arrangement of equipment needed to ensure proper functioning of plant; line sizes; and principal instrument.

6. Plant & Process

7. General Structure of Plant
Raw Material
Storage
Process
Product
Storage
Utilities

8. It is important to keep in mind that design problems are open ended and may have many solutions that are attractive and near optimal.

9. No two designers design a complex process following exactly the same steps.

10. Process Design Constraints
When considering possible ways of achieving the objective, the designer will be constrained by many factors which will narrow down the number of possible designs; but, there will rarely be just one possible solution to the problem, just one design.

11. Process Design Constraints
Several alternative ways of meeting the objective will normally be possible, even several best designs, depending on the nature of the constraints.

12. Constraints
External constraints - the constraints that are outside the designer’s influence.
- Physical laws
- Resources
- Safety regulations
- Economics
- Standard & Codes
- Government controls

13. Constraints
Internal constraints - the constraints that are capable of relaxation by the designer as part of his general strategy in seeking the best design.
- Choice of process/unit operations/process conditions/nature of construction/etc.

14. Steps in Designing Chemical Processes
Assess Primitive Problem
Survey Literature
Process Creation
Development of Base Case
Detailed Process Synthesis Using Algorithmic Method
Plantwide Controllability Assessment
Detailed Design, Equipment Sizing and Cost Estimation, Profitability Analysis, and Optimization.

15. Steps in Designing Chemical Processes
Written Process Design Report and Oral Presentation
Final Design, Construction, Start-up, and Operation

16. The “Process” of Design
Conception and Definition
Flow Sheet Development
Design of Equipment
Economic Analysis
Optimization
Reporting

17. Unit Operations for Chemical Process
Chemical reaction
Separation of chemicals
Phase separation
Change of temperature
Change of pressure
Change of phase
Mixing and splitting of streams or branches

18. Chemical Reactors Stirred Tank Tubular Flow Reactors
Gas-Liquid Reactions
Fixed Bed Reactors
Moving Bed Reactors
Fluidized Bed Reactors
Kiln and Hearth Furnaces

19. Solid-Solid Separations
Screening (sieving)
Liquid-solid cyclones
Hydroseparators and sizers (classifier)
Tables
Classifying centrifuges
Flotation separators
Magnetic separator
Electrostatic separators

20. Liquid-Solid Separations
Thickeners and Clarifiers
Filtrations
Centrifuges
Hydrocyclones (liquid-cyclone)
Pressing (expression)
Solid drying

21. Gas-Solid Separations
Gravity settle
Impingment separators
Centrifugal separators (cyclones)
Filters
Wet scrubbers
Electrostatic precipitators

22. Gas-Solid Separations
Gravity settle
Impingment separators
Centrifugal separators (cyclones)
Filters
Wet scrubbers
Electrostatic precipitators
Phase separator (Flash Drum)

23. Liquid-Liquid Separations
Decanters (settlers)
Plate separators
Coalesces
Centrifugal separators

24. Separation of Dissolved Solids
Evaporators
Crystallization

25. Separation of Dissolved Liquids
Distillation
Solvent extraction (liquid-liquid extraction)
Crystallization
Adsorption
Membrane Separation

26. Heat Transfer Equipment
Double-pipe Heat Exchangers
Shell-Tube Heat Exchangers
Plate Heat Exchangers
Direct-contact Heat Exchangers
Air-cooled Exchangers
Fired Heaters (Furnaces and Boilers)
Condensers
Reboilers and Vaporisers

27. Change of Pressure Increase of Pressure - Pump - Compressor
Decrease of Pressure
- Vale
- Expander

28. Mixing and Agitation Stirred Tank Suspension of Solids Gas Dispersion
In-Line-Blenders and Mixers

29. Transfer of Solids Equipment for Gas Transport - Fans - Compressors
Equipment for Liquid Transport
- Pump

30. Fluid Transport Equipment
Slurry Transport
Pneumatic Conveying
Mechanical Conveyors and Elevators
- Screw Conveyors
- Belt Conveyors
- Bucket Elevators and Carriers
Solids Feeders

31. Utilities Steam Heat Transfer Fluids Refrigerants Cooling Water
Cooling Air
Fuel
Compressed Air
Instrument Air
Electricity