Enhancement of gas-liquid mass transfer in microchannels by rectangular baffles

Abstract

The configuration of microchannel with staggered rectangular baffles was constructed to improve the gas-liquid mass transfer efficiency. The influences of the baffle blockage length, baffle interval, channel width and the gas and liquid superficial velocities on the volumetric mass transfer coefficient, pressure drop and efficient energy efficiency for CO2/water system were investigated experimentally. The enhancement mechanism of mass transfer was analyzed according to the gas-liquid two-phase flow pattern in baffled microchannels. The comparison of the volumetric mass transfer coefficient between the microchannels with and without baffles was performed to present the intensification of baffled structure to mass transfer. The increases of baffle blockage length and channel width, and the reduction of baffle interval are conducive to enhancing gas-liquid mass transfer, with the maximum enhancement factor up to 2.8. Although the baffled structure could lead to an increase in pressure drop within 0.5 kPa in absolute value or 23% in relative value, which is an acceptable rise for practical application. Moreover, effective energy efficiency could reach to 2.25 in the case of the maximum enhancement of mass transfer. This study could provide theoretical guidance for the development and optimization of rectangular baffled microdevices for process intensification.