Question

Film theory, penetration theory, surface renewal theory definition

Answer 1

1 Gas- Liquid and Gas –Liquid –Solid Reactions
Basic Concepts

2 Proper Approach to Gas-Liquid Reactions
ReferencesMass Transfer theoriesGas-liquid reaction regimesMultiphase reactors and selection criterionFilm model: Governing equations, problem complexitiesExamples and Illustrative ResultsSolution Algorithm (computational concepts)

3 Theories for Analysis of Transport Effects in Gas-Liquid Reactions
Two-film theory1. W.G. Whitman, Chem. & Met. Eng., (1923).2. W. K. Lewis & W. G. Whitman, Ind. Eng. Chem., 16, 215 (1924).Penetration theoryP. V. Danckwerts, Trans. Faraday Soc., (1950).P. V. Danckwerts, Trans. Faraday Soc., (1951).P. V. Danckwerts, Gas-Liquid Reactions, McGraw-Hill, NY (1970).R. Higbie, Trans. Am. Inst. Chem. Engrs., (1935).Surface renewal theoryP. V. Danckwerts, Ind. Eng. Chem., (1951).Rigorous multicomponent diffusion theoryR. Taylor and R. Krishna, Multicomponent Mass Transfer,Wiley, New York, 1993.

4 Two-film Theory Assumptions
1. A stagnant layer exists in both the gas and the liquid phases.2. The stagnant layers or films have negligible capacitance and hence a local steady-state exists.3. Concentration gradients in the film are one-dimensional.4. Local equilibrium exists between the the gas and liquid phases as the gas-liquid interface5. Local concentration gradients beyond the films are absent due to turbulence.

5 Two-Film Theory Concept W. G. Whitman, Chem. & Met. Eng
pApAipAi = HA CAi•Bulk GasGas FilmLiquid FilmBulk LiquidCAi•CAbxx + xLx = Gx = 0x = L