Mass Transfer in a Liquid Film of a Wetted-Wall Column

Abstract

From the viewpoint of the surface renewal theory or the film penetration theory, mass transfer in a liquid film was considered.The theoretical equation (6) based on the surface renewal theory was derived by assuming that the surface age distribution should change with contact time and moreover that the liquid surface is renewed by the liquid at zero concentration.Secondly, the theoretical equation (7) based on the film penetration theory was derived by assuming the presence of a region where unsteady molecular diffusion is controlling, which led to the assumption that the concentration of the bulk of liquid increases with contact time.As shown in Figs. 3-8, these theoretical equations are compared with experimental results of CO2 absorption in water.Eq. 6 agrees well with the data at Γ=1.9 and 0.9g/cm·s, but deviates from the data in the case of lower flow rates. This disagreement is due to the fact that at the lower flow rates there occurs a considerably larger concentration of the liquid bulk and therefore the newly-formed surface is not necessarily replaced by the liquid at zero concentration.Eq. 7 agrees with the data over a wide range of flow rates as compared with other equation.