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Chemical Engineering Plant Design. Lek Wantha Lecture 01. What is Chemical Process?. A chemical process is a process which raw material are transformed or converted into desired product. Strategies for Chemical Product Design. Need Ideas Selection Manufacture. Need for Process Design.
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Chemical Engineering Plant Design LekWantha Lecture 01
What is Chemical Process? A chemical process is a process which raw material are transformed or converted into desired product.
Strategies for Chemical Product Design Need Ideas Selection Manufacture
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
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.
General Structure of Plant Raw Material Storage Process Product Storage Utilities
It is important to keep in mind that design problems are open ended and may have many solutions that are attractive and near optimal.
No two designers design a complex process following exactly the same steps.
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.
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.
Constraints External constraints - the constraints that are outside the designer’s influence. - Physical laws - Resources - Safety regulations - Economics - Standard & Codes - Government controls
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.
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.
Steps in Designing Chemical Processes Written Process Design Report and Oral Presentation Final Design, Construction, Start-up, and Operation
The “Process” of Design Conception and Definition Flow Sheet Development Design of Equipment Economic Analysis Optimization Reporting
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
Chemical Reactors Stirred Tank Tubular Flow Reactors Gas-Liquid Reactions Fixed Bed Reactors Moving Bed Reactors Fluidized Bed Reactors Kiln and Hearth Furnaces
Solid-Solid Separations Screening (sieving) Liquid-solid cyclones Hydroseparators and sizers (classifier) Tables Classifying centrifuges Flotation separators Magnetic separator Electrostatic separators
Liquid-Solid Separations Thickeners and Clarifiers Filtrations Centrifuges Hydrocyclones (liquid-cyclone) Pressing (expression) Solid drying
Gas-Solid Separations Gravity settle Impingment separators Centrifugal separators (cyclones) Filters Wet scrubbers Electrostatic precipitators
Gas-Solid Separations Gravity settle Impingment separators Centrifugal separators (cyclones) Filters Wet scrubbers Electrostatic precipitators Phase separator (Flash Drum)
Liquid-Liquid Separations Decanters (settlers) Plate separators Coalesces Centrifugal separators
Separation of Dissolved Solids Evaporators Crystallization
Separation of Dissolved Liquids Distillation Solvent extraction (liquid-liquid extraction) Crystallization Adsorption Membrane Separation
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
Change of Pressure Increase of Pressure - Pump - Compressor Decrease of Pressure - Vale - Expander
Mixing and Agitation Stirred Tank Suspension of Solids Gas Dispersion In-Line-Blenders and Mixers
Transfer of Solids Equipment for Gas Transport - Fans - Compressors Equipment for Liquid Transport - Pump
Fluid Transport Equipment Slurry Transport Pneumatic Conveying Mechanical Conveyors and Elevators - Screw Conveyors - Belt Conveyors - Bucket Elevators and Carriers Solids Feeders
Utilities Steam Heat Transfer Fluids Refrigerants Cooling Water Cooling Air Fuel Compressed Air Instrument Air Electricity