CHAPTER 9

CONTACT-EQUILIBRIUM PROCESSES

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Introductionphase distribution equilibrium distribution coefficients
contact equilibrium separation
PART 1: THEORY
Concentrationsmole fractionpartial pressureAvogadro's Law
Gas/Liquid Equilibriapartial vapour pressureHenry's Law
       solubility of gases in liquids
Solid/Liquid Equiibriasolubility in liquids
       solubility/temperature relationshipsaturated solution
       supersaturated solution
Equilibrium-Concentration Relationshipsoverflow/underflow
       equilibrium diagram
Operating Conditionscontact stagesmass balances
Calculation of Separation in Contact/Equilibrium Processes
       combining equilibrium and operating relationships
       deodorizing/steam strippingMcCabe/Thiele plot

PART 2: APPLICATIONS
Gas Absorption
Rate of Gas AbsorptionLewis and Whitman Theory
Stage-equilibrium Gas Absorption number of contact stages
Extraction and Washing
Rate of Extraction
Stage-equilibrium Extraction equilibrium and operating conditions
       McCabe Thiele diagram
Gas-absorption Equipment
Washing
Extraction and Washing Equipmentextraction battery
Crystallizationmother liquor
Crystallization Equilibriumsolubility and saturationnucleation
       metastable region
       seed crystalsheat of crystallization
Rate of Crystal Growth
Stage-equilibrium Crystallization
Crystallization Equipmentscraped surface heat exchanger
       evaporative crystallizer
Membrane Separationsosmotic pressureultrafiltration
       reverse osmosis
Rate of Flow Through Membranesvan't Hoff equation
       Diffusion equationsSherwood numberSchmidt number
Membrane Equipment
DistillationEquilibrium relationships
       boiling temperature/concentration diagram azeotropes
Steam Distillation
Vacuum Distillation
Batch Distillation
Distillation Equipment
Summary
Problems

Examples in this Chapter:
9.1. Mole fractions of ethanol in water
9.2. Mole fractions in air
9.3. Solubility of carbon dioxide in water
9.4. Single stage steam stripping, of taints from cream
9.5. Multiple stage steam stripping of taints from cream
9.6. Counter current extraction of oil from soya beans with hexane
9.7. Washing of casein curd
9.8. Crystallization of sodium chloride
9.9. Heat removal in crystallization cooling of lactose
9.10. Multiple stage sugar crystallisation by evaporation
9.11. Reverse osmosis: concentration of sucrose solution
9.12. Ultrafiltration of whey
9.13. Distillation of alcohol/water mixture

Figures in this Chapter:
9.1 Solubility of sodium nitrite in water
9.2 Contact equilibrium stages
9.3 Flows into and out from a stage
9.4 Steam stripping: McCabe-Thiele plot
9.5 Hexane extraction of oil from soya beans in stages
9.6 Hexane extraction of oil from soya beans: McCabe-Thiele plot
9.7 Extraction battery
9.8 Solubility and saturation curves for sucrose in water
9.9 Reverse osmosis systems
9.10 Boiling temperature/concentration diagram
9.11 Distillation column (a) assembly, (b) bubble-cap trays