Liquid phase mass transfer in packed bed reactor with cocurrent gas-liquid downflow

Abstract

Volumetric absorption coefficient (ka)lg, specific interfacial area algand mass transfer coefficient klgwere measured for two-phase cocurrent flow of O2—water and CO2NaOH systems in a column packed with glass spheres of 3 different sizes (2.59–12.2 mm). Values of (ka)lgobserved were so high as to be that can be hardly attainable in conventional gas-liquid contactors. This is due to large algof small bubbles dispersed in liquid where algvery often exceeds the geometrical surface area of packing. Values of klgrange from 2 to 8 × 10−4m/sec, which are comparable to that of circulating bubbles in the usual systems. The effect of superficial gas velocity on (ka)lgand algis much greater than that in a countercurrent packed column, while the effect of liquid velocity is approximately same. A liquid-phase energy loss Elper unit volume of liquid contained in a bed was newly defined as a measure of microscopic flow intensity and was used for discussion and correlation of mass transfer properties. It was found that the bubble diameter is proportional to El−2/5. © 1974, The Society of Chemical Engineers, Japan. All rights reserved.