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Chemical Processes Outline. MotivationsReactionsSeparationsCalculations using Conservation of Mass and EnergyDistillation. Chemists vs Chemical Engineers. ChemistsDesign reaction pathways to produce a chemical from raw materialsWork in the laboratory setting to produce material on the gram
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1. Chemical Processes What is Engineering?
July 25, 2007
2. Chemical Processes Outline
Motivations
Reactions
Separations
Calculations using Conservation of Mass and Energy
Distillation
3. Chemists vs Chemical Engineers Chemists
Design reaction pathways to produce a chemical from raw materials
Work in the laboratory setting to produce material on the gram to kilogram scale Chemical Engineers
Design a process to scale the chemists process to mass produce the product
Work in a chemical plant to produce material in the ton and beyond range
4. Why do we care about Chemical Engineering?
5. If that isnt reason enough
In the United States
170 Major Chemical Companies
$400 Billion a year
Employs more than a million workers
6. Molecules that Chemicals Engineers work with Small and Simple
Helium (He)
Ammonia (NH3)
Hydrogen Flouride (HF)
Trinitrotoluene (C6H2(NO2)3CH3)
Large and Complicated
Insulin C257H383N65O77S6
Large and Simple
Polyvinyl Chloride (-CH2-CHCl-)n
7. How to Produce Chemicals Two methods to obtain a desired chemical
Design a reactor to produce a chemical from raw materials
To isolate the compound that exists in combination with other substances through separation processes
8. Chemical Reactions
9. Possible Problem with Exothermic Reactions
10. Separations Molecular Property
Boiling Point
Freezing Point
Particle size
Affinity to a stationary phase
Density
Selective affinity to solid particles Separation Process
Distillation
Crystallization
Filtration
Chromatography
Centrifuge
Adsorption
12. Mass and Energy Balances Balance Equation
Input + generation Output = Accumulation
13. Mass and Energy Balances For non-reacting systems Generation = 0
For systems operated at steady state Accumulation = 0
Mass and Energy Balances reduce to
Input = Output
14. Separations Calculation
15. Separation Calculation
16. Separations: Distillation
17. Distillation
18. Distillation
20. Distillation
21. Distillation: McCabe-Thiele Calculation
22. Distillation: McCabe-Thiele
23. Distillation Benefits
Applicable for many liquid systems
Technology is well developed
High Throughput
24. Azeotrope
25. Distillation
26. Conclusions
Chemicals are produced by reactions or separations
The driving force for separations are property differences
Mass and Energy are Conserved
Distillation is the workhorse of separations
27. Todays Laboratory Three Parts:
Energy Transfer
Chromatography
Batch Distillation
(One equilibrium stage)
28. Todays Laboratory: Energy Transfer Want efficient transfer and conversion of energy ($$)
In lab, will be examining energy transfer in the form of heat: warming a pot of water with a hot plate what is the efficiency of energy transport from electricity to the water?
29. Todays Laboratory: Chromatography Separation technique that takes advantage of varying affinities of solutes for a given solvent traveling up a filter paper.
Solutes: colored dyes
Solvents: water, methanol, 2-propanol
Measure the distance traveled by the solutes and solvents!
**Methanol and 2-propanol are poisons! Wear safety goggles, do not ingest or inhale and rinse skin immediately if spilled.
30. Todays Laboratory: Distillation Using distillation to separate a liquid mixture of ethanol and water
Ethanol is the more volatile material (it will boil first)
Take samples of distillate with time to determine the concentration of ethanol in the mixture!
**Ethanol is a poison! Wear safety goggles, do not ingest or inhale and rinse skin immediately if spilled.