Gas Holdup and Gas Entrainment Rate in Downflow Bubble Column with Gas Entrainment by a Liquid Jet Operating at High Liquid Throughput

Abstract

Flow behavior of downflow bubble columns with gas entrainment by a liquid jet operating at high throughputs was investigated in an air–water system. With increasing liquid throughput above the churn-turbulent flow regime, stable downward bubbling flow without bubble coalescence was again obtained. Gas holdup and gas entrainment rate under bubbling downflow conditions were measured and their dependencies on operational conditions were clarified empirically. Experimental equations were proposed to estimate gas holdup and gas entrainment rate. Performance of gas supply was evaluated in terms of energy efficiency and compared with that of other gas-liquid aerators. The evaluation showed that the gas-entraining capacity of this apparatus is sufficient and that its energy efficiency for gas supply is high.