Gas-phase mass transfer in a centrifugal contactor

Abstract

The liquid-side mass transfer rate in a centrifugal gas-liquid contactor has been reported to be several times higher than that in conventional packed beds. However, no direct measurement of the gas-side mass transfer coefficient has been reported. We present experimental studies on gas-side mass transfer in a rotating packed bed with wire-gauze packing. Contrary to expectations, the gas-side mass transfer coefficient was much lower than that in conventional packed columns. An analysis of the gas flow, based on the equations of motion, revealed that the gas undergoes solid-body-like rotation in the rotor because of the drag offered by the packing. Therefore, the mass transfer coefficient should be in the same range as that in conventional packed columns. The lower value of the coefficient found experimentally is attributed to liquid maldistribution. The possibility of enhancing the mass transfer coefficient by enhancing the slip between the gas and the packing was explored by using a stack of closely spaced disks as the packing. Mass transfer studies with a pair of disks were conducted. Higher throughputs and mass transfer rates than those with the wire-gauze packing were obtained. A stack of disks as packing appears to hold promise.