What is Chemical Process.ppt

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
Process Product
Storage
Raw Material
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