EFFECTS OF SURFACE-ACTIVE SUBSTANCES ON GAS HOLDUP AND GAS-LIQUID MASS TRANSFER IN BUBBLE COLUMN

Abstract

The effects of surfactants and antifoam agent on the gas holdup ε, the liquid-phase mass transfer coefficient k_L and the volumetric liquid-phase mass transfer coefficient k_La in a bubble column were studied experimentally. An addition of surfactants such as n-alcohols to water increases e and decreases k_L, and an addition of antifoam agent to water decreases ε, k_L and k_La. However, the degree of reduction of k_L value by an addition of surfactant to water is lower for bubble swarms in a bubble column than that for a single bubble in stagnant liquid. Based on these observations, the previous model for estimating k_L of a single bubble in aqueous solutions of surface-active substance is modified so as to be applicable to the estimation of k_L for bubble swarms in a bubble column.