Individual mass transfer resistances in liquid-liquid extraction

Individual film resistances in mass transfer were determined for the methyl isobutyl ketone-water system in a 4-inch I.D. spray column. Column height was varied from one to four feet. Individual film resistances (as H.T.U.) and individual capacity coefficients (ka) were measured by passing the two partially miscible liquids counter - currently through the column. The degree to which each stream approached saturation at the exit served as a measure of each film resistance. By presaturating one of the liquids, a unidirectional mass transfer was obtained and the operating procedure simplified. The outlet concentrations leaving the column were converted into ka's and H.T.U.'s and analyzed as functions of flow rate and column height. The variation of individual mass transfer coefficient, k, with flow rate was also studied by assuming constant droplet size and constant rate of droplet fall or rise in the column. A tentative correlation of mass transfer rate with the physical properties of the liquid system such as density, viscosity, interfacial tension, and molecular diffusivity, was proposed.