Gas-lift circulation of a liquid between two inter-connected bubble columns

Abstract

A pneumatically-mixed novel configuration of two inter-connected bubble column reactors is reported using air-water to demonstrate the device, enabling circulation of a liquid between the columns solely by a gas-lift mechanism. The new reactor may be used for circulating a high temperature/corrosive liquid between the columns, enabling the cyclical processing of a liquid medium with two different gaseous reactants. The effects of superficial gas velocity, unaerated liquid height in the columns and the diameter of aeration nozzles are discussed with reference to the gas holdup in, and rate of liquid circulation between, the two columns, together with the energetics of circulation. The height of the gas-free liquid in the reactor was found to influence the liquid circulation velocity positively, but the effect of aeration nozzles diameter was marginal. The lowest and highest measured flow rates of circulating water between the columns were 0.7 dm3 min−1 and 4.2 dm3 min−1, respectively.