Back-Flow Ratio of Liquid between Stages in Multi-Stage Bubble Columns

Abstract

Longitudinal mixing of liquid in multi-stage bubble columns was measured by a delta-response method for cocurrent and countercurrent operations. Response curves obtained were analyzed by the diffusion/ back-flow model, in which it was assumed that the diffusion model was applicable in each stage and there was back-flow between stages, and the back-flow ratio, β, was determined.
β in the range of 1.5 4.5 cm/sec of superficial gas velocity, u_g, is a function of both superficial liquid velocity and open area ratio of perforated baffle plates, and an empirical equation is obtained. β in the range of u_g>=13 20 cm/sec is approximated by two empirical equations, one for non pulsating flow region and other for pulsating flow region. β in the range of u_g=4.5 13 cm/sec can be read by the straight line which passes values of β on a log-log graph at u_g=4.5 cm/sec and u_g= 13 cm/sec calculated from the above equations.