Study on the process intensification of superaerophobic materials to improve CO2 mass transfer efficiency

Abstract

Chemical absorption is the most widely used method in capturing CO2 from flue gas, in which the gas-liquid mass transfer process is the control step of the absorption rate; the spherical structure and easy flow characteristics of bubbles in the liquid phase affect the gas-liquid mass transfer efficiency. This study carefully examines the effect of superaerophobic surfaces on the mass transfer efficiency of CO2 bubbles on both dynamic and static behaviors. The results show that the 0.5 mol/L MDEA solution can absorb CO2 bubbles within 70 s when the CA (Contact Angle) of the superaerophobic surface bubbles reaches more than 150°. However, after contacting the superaerophilic substrate, the mass transfer area between the gas and liquid phases increases instantly and the CO2 bubbles burst rapidly and form a gas film within 18 ms. After that, the absorption saturation time of the absorption tower using superaerophilic packing is 25% less than that using untreated packing. Therefore, the superaerophilic packing can significantly increase the gas-liquid contact area and the mass transfer efficiency.