Effect of unaerated liquid height on hydrodynamic characteristics of an external-loop airlift reactor

Abstract

The effects of the unaerated liquid height (0  h  0.20 m), the superficial gas velocity (0.02 UG 0.18 ms 1) and the downcomer-to-riser cross-sectional area ratio (0.11 Ad/ Ar 0.53) on the hydrodynamic characteristics, such as the gas holdups in the riser and the downcomer, the circulation time, the circulation liquid velocity and the mixing time, in an external-loop airlift reactor were systematically investigated. The unaerated liquid height, the superficial gas velocity and the downcomer-to-riser cross-sectional area ratio were important parameters which strongly affected the hydrodynamic characteristics of the airlift reactor. As the unaerated liquid height increased, the gas holdups in the riser and the downcomer, the circulation time and the mixing time decreased whereas the circulation liquid velocity increased.