Enhancement effect and mechanism of gas-liquid mass transfer by baffles embedded in the microchannel

The enhancement of gas-liquid mass transfer by baffles embedded in a microchannel was investigated experimentally for CO2 absorption into monoethanolamine/1-butyl-3-methylimidazolium tetrafluoroborate (MEA/Bmim][BF4]) aqueous solutions. The influences of baffle size on mass transfer rate and pressure drop were studied through varying the MEA/[Bmim][BE4] concentration ratio, gas-liquid flow rate and blockage ratio. Experimental results showed that the proper baffle configuration could improve effectively gas-liquid mass transfer performance. Although the pressure drop of the baffled microchannel has slight increase (the maximum growth 0.3 kPa, or 20% in relative term) in comparison with the unobstructed microchannel, it is acceptable for industrial application. Under lower MEA/[Bmim][BE4] concentration ratios, higher two-phase flow rates and blockage ratios, the mass transfer enhancement is more pronounced and the enhancement factor could reach to 1.5. A new empirical correlation of enhancement factor is proposed with good predictive performance. (C) 2019 Elsevier Ltd. All rights reserved.