Course Title: 
Diffusional Mass Transfer Operations
Course Code: 
Year Taught: 
Subject Core
Undergraduate (UG)
School of Engineering

'Diffusional Mass Transfer Operations' is a course offered in the fifth semester of B. Tech. in Chemical Engineering program at School of Engineering, Amrita Vishwa Vidyapeetham, Coimbatore.

Unit 1

Molecular diffusion in fluids, Fick’s Law of diffusion, steady state diffusion under stagnant and laminar flow conditions. Diffusivity measurement and estimation, multi-component diffusion, diffusion in solids and its applications, eddy diffusion, mass transfer coefficients, theories of mass transfer, analogy equations, application of empirical correlations to known geometry suchas flat plates, wetted wall columns.Concept of mass transfer coefficients, inter phase mass transfer, two film theory, relationship between individual and overall mass transfer coefficients. Mass transfer in fluidized bed, flow past solids and boundary layers.Equipments for countercurrent and concurrent mass transfer operations.

Unit 2

Absorption and stripping – Gas liquid equilibria, Raoults and Henry’s laws,Solubility of gases in liquid, choice of solvent; Material balance in countercurrent andconcurrent absorption and stripping, L/G ratio,absorption factor; Equipment for absorption, Graphical and analytical methods for tray column, packed columns for absorption: rate based designs, HTU, NTU and HETP concepts, absorption with chemical reaction. Humidification and dehumidification: vapour liquid equilibria, theory of wet-bulb temperature and adiabatic saturationtemperature, Lewis relation, Lewis relation, psychometric chart, humidification and dehumidification equipments, enthalpy transfer concepts – temperature profiles in humidifier and dehumidifiers theory. Classification and design of cooling towers.

Unit 3

Drying: Solid-gas equilibria, mechanism of drying, drying curves, modes ofdrying operations, classification of dryers, industrial dryers for batch and continuous drying, time of drying in batch operation, estimation of size of rotary dryer based on rate concept.Crystallization:Equilibrium, theories of crystallization, purity, yield, energy requirements, kinetics of crystallization – nucleation and growth; population balance model, MSMPR crystallizer, crystallisation equipment.

  • R. E. Treybal, Mass Transfer Operations, 3rd Edn. McGraw Hill 1981
  • Binay K. Dutta, Principles of Mass Transfer and Separation Processes, PHI Learning Private Ltd, 2013
  • J. D. Seader, Ernest J. Henley, Separation Process Principles, 2nd Edition, Wiley India, 2011
  • Coulson, J. M. and Richardson, J. F. Chemical Engineering Vol. II, 4th Edn., Asian Books Pvt. Ltd. India. 1998.
  • McCabe, W. L. Smith, J. C. and Harriot, P. “Unit Operations in Chemical Engineering, 6th Edn, McGraw Hill Edn, 2001.
  • J. R. Welty, C. E Wicks, G. L. Rorrer and R. E. Wilson, Fundamentals of Momentum, Heat and Mass Transfer, 4th Edition, Wiley, 2000.
  • Foust, A. S. Wenzel, L. A. Clump, C. W. Naus, L., and Anderson, L. B. ‘Principles of Unit Operations’, 2nd Edn. Wiley, 1980.
  • Geankoplis, C. J., “Transport Processes and Unit Operations”, 4th Edition, Prentice Hall of India Pvt. Ltd, New Delhi, 2004.