ADVANCED MASS TRANSFER Amirkabir University of Technology (Tehran Polytechnic) ADVANCED MASS TRANSFER By: Dr. Frazin Zokaee Chemical Engineering Department Winter 2009

Course Outline: CHAPTER 1: FLUX DEFINITION Mass and Molar Transport by Convection Summary of Mass and Molar Fluxes Fick’s Law CHAPTER 2: DIFFERENTIAL EQUATIONS OF MASS TRANSFER Differential equation for mass transfer Boundary conditions CHAPTER 3: MOLECULAR DIFFUSIVITIES Diffusivities in Gases Diffusivities in Liquids By Dr. Zokaee

CHAPTER 4: MOLECULAR DIFFUSION Steady-State Molecular Diffusion Steady-State Equimolal Counter Diffusion in Gases Steady-State Unimolal Unidirectional Diffusion in Gases Molecular Diffusion in Liquids Diffusion through a Stagnant Gas Film Diffusion with a Moving Interface Diffusion through a Nonisothermal Spherical Film Diffusion with a Heterogeneous Chemical Reaction Diffusion with a Slow Heterogeneous Reaction Diffusion with a Homogeneous Chemical Reaction Unsteady-State Diffusion in a Sphere Unsteady-State Diffusion in a Slab Unsteady-State Diffusion in a Cylinder By Dr. Zokaee

CHAPTER 5: MECHANISMS OF MASS TRANSFER The Two-Film Theory The Penetration Theory The Theory of Penetration with Random Surface Renewal CHAPTER 6: MASS TRANSFER IN LAMINAR FLOW Mass Transfer in the Laminar Boundary Layer on a Flat Plate (Integral Solution) Mass Transfer in Laminar Natural Convection on a Vertical Plate Mass Transfer in a Falling Liquid Film in Laminar Flow Mass Transfer Between a Gas Phase and a Falling Liquid Film (Gas Absorption) Mass Transfer Between an Inclined Plate and a Falling Liquid Film(Solid Dissolution) Gas Absorption with Rapid Reaction تعداد جلسات بعدا اصلاح شود By Dr. Zokaee

CHAPTER 7: MASS TRANSFER IN TURBULENT FLOW Mass Transfer in the Turbulent Boundary Layer on a Flat Plate Mass Transfer in Turbulent Natural Convection on a Vertical Plate Mass Transfer Between an Inclined Plate and a Falling Liquid Film in Turbulent Flow Analogies Between Momentum, Heat and Mass Transfer Reynolds Analogy: Analogy Assuming Only a Turbulent Core Prandtl Analogy: Analogy Assuming a Laminar Sublayer and a Turbulent Core Von karman Analogy: Analogy Assuming a Laminar Sublayer, a Buffer Zone and a Turbulent Core Analogies in terms of j Factors By Dr. Zokaee

Text Book A. H. P. Skelland, Diffusional Mass Transfer, John Wiley and Sons (1974). R.B. Bird, W.E. Steward and E.N. Lightfoot, Transport Phenomena, 2nd Ed., John Wiley and Sons (2002). J. R. Welty, C. E. Wicks, R. E. Wilson and G. Rorrer, Fundamentals of Momentum, Heat, and Mass Transfer, 4th Ed., John Wiley & Sons (2001). By Dr. Zokaee

What is Mass Transfer? The transport of one component from one place to another is called Mass Transfer. Motion of molecular or fluid elements caused by some form of potential or driving force is called Mass Transfer. Diffusional Mass Transfer involves the migration of one substance through another under the influence of a concentration gradient . Must have a mixture of two or more species for mass transfer to occur. By Dr. Zokaee

Separation processes Gas - Liquid Single phase Gas - Solid Absorption Stripping Distillation Evaporation Humidification Dehumidification Single phase Gas - Solid Adsorption Desorption Drying Sublimation Direct contact Liquid - Solid Adsorption Desorption Leaching Crystallization Between two phase Liquid - Liquid Indirect contact Membrane separation Liquid-Liquid Extraction By Dr. Zokaee

Types of Membrane Porous membrane Dense membrane Solid diffusion Permeability By Dr. Zokaee

Driving force in Membrane separation Microfiltration Pressure gradient (∆P) Ultrafiltration Dialysis Concentration gradient (∆C) Nanofiltration Pervaporation Reverse Osmosis Electric gradient (∆E) Gas Permeation Electro Dialysis (ED) Liquid Membrane Temperature gradient (∆T) Membrane Distillation By Dr. Zokaee

Mechanical Separation Mechanical work and calculations are according the fluid flow in porous media and centrifugal force and etc. Mixing Size reduction Sedimentation Centrifugation Filtration By Dr. Zokaee

Separation processes Continues Packed towers Spray towers Bubble column Wetted wall column Stage wise Tray towers Mixer and Settler By Dr. Zokaee