Characteristics analysis of multi-channel ceramic membranes for dilute gas absorption in falling film operation

Capturing dilute gases has posed a significant challenge due to the extremely low mass transfer driving force associated with them. Falling film-based absorption using porous membranes emerges as a promising technology for gas separation, offering a substantial gas–liquid interface area while simultaneously eliminating mass transfer resistance within pores that is inherent in hydrophobic membrane-based absorption processes. In this study, we investigated the mass transfer performance of multi-channel ceramic membranes in falling film-based dilute CO₂ absorption under various gas and liquid operating conditions. Experimental tests and computational fluid dynamics (CFD) simulations were conducted to examine the effects of pore size and geometrical configuration on the distribution of liquid and gas flows across different channels. Simulations indicated that the optimization of multi-channel ceramic membranes for the falling film-based dilute gas absorption should prioritize achieving a more rational distribution of gas–liquid flows. When the disparity between liquid and gas distribution in the outermost channels exceeded 40%, as opposed to cases where the difference was within 20%, there was a reduction of over 50% in mass transfer performance.