Fluxes in Gas and Liquid Films

Different theories and methods [6] are available for the calculation of molar fluxes, Nq- and LA which are needed in the bulk-phase mass balances of ideal gas-liquid reactors. Equations 7.15 and 7.16, Equations 7.22,7.25, and 7.26, and Equations 7.33 and 7.34. According to the two-film theory, molecular diffusion and a chemical reaction occur simultaneously 

If Pick s law is valid for both the gas and the liquid films, fluxes N - and are defined as 

Dividing Equation 7.37 by Az (distance element in z coordinate) yields 

FIG U RE 7.17 Diffusion and reaction in gas and liquid films (. slow diffusion rate,—more rapid diffusion rate). 

Assuming that the diffusion coefficient is approximately constant and allowing that Az 0, we obtain the balance equation 

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