Investigation of membrane wetting for CO2 capture by gas–liquid contactor based on ceramic membrane

Abstract

In recent years, global climate change caused by excessive CO2 emissions has attracted wide attention. Within this context, CO2 capture by gas–liquid contactor based on membranes is one of the most promising technologies for post-combustion CO2 capture. However, mass transfer deterioration due to membrane wetting becomes one of barriers for its development. In this paper, based on Laplace-Young equation, reliable individual membrane pore wetting model is constructed to demonstrate detailed wetting process inside membrane pores, which is verified by molecular dynamic (MD) numerical simulation. The wetting conditions of ceramic membrane with 1.26 µm average pore size and 51.4° contact angle are investigated in experiments. The results show that neither average nor maximum pore diameters can accurately predict liquid and bubble breakthrough pressures of ceramic membrane. The actual liquid and bubble breakthrough pressures of ceramic membrane are slightly lower than critical liquid and bubble breakthrough pressures corresponding to the maximum pore size. The wetting state of ceramic membrane can be determined by combining individual pore wetting model and actual membrane pore distribution. In addition, for practical application process of CO2 capture by gas–liquid contactor with ceramic membrane, some suggestions to avoid membrane wetting are proposed for selection of ceramic membrane and system operation perspective. The membrane wetting analysis method proposed in this paper not only contributes to future applications of ceramic membrane in CO2 capture, but is also widely applicable to other gas–liquid contactors in membrane separation process.