Synergistic effect of functionalized ionic liquid and alkanolamines mixed solution on enhancing the mass transfer of CO2 absorption in microchannel

A novel hybrid absorbent by combining functionalized ionic liquid (IL) 1-(3-aminopropyl)-3-methylimidazolium tetrafluoroborate [Apmim][BF4] with alkanolamines (monoethanolamine (MEA) and N, N-diethylethanolamine (DEEA)) was proposed for CO2 capture. By means of a high-speed camera, the capacity and mass transfer performance of CO2 absorption into the hybrid absorbent were investigated experimentally in microchannel over a wide range of concentration ratios (IL: amine) at the room temperature and atmosphere pressure. Three flow patterns were observed: Taylor-bubbly flow, Taylor flow and Taylor-annular flow. The results show that the CO2 loading and mass transfer coefficient of alkanolamine solution could be improved remarkably by the addition of an appropriate amount of [Apmim][BF4]. The molar ratio 3:2 of IL to amine was found to be optimal for CO2 loading and mass transfer. Furthermore, the influences of gas and liquid flow rates on mass transfer were studied, and a new predicting correlation for CO2 volumetric mass transfer coefficient was proposed.