Modeling the mass transfer process in membranes for carbon capture and separation with concentration polarization effect

Abstract

Membrane separation is regarded as the most promising carbon capture technology due to its low operating cost and requirements for installation. The main parameters in membrane separation are selectivity and permeability. This study presents a mathematical model to analyze factors influencing membrane separation. The separation process was investigated based on mass transfer theory by analyzing the influence of pressure, initial composition, permeability and doped gas on the separation result. An increase in pressure ratio, mole fraction of CO2 and permeability will improve the separation efficiency. The influence of doped gas on the separation efficiency is depended on the permeability and the content of the doped gas. Moreover, the study also presents the effect of concentration polarization on the separation. Results of studied cases provide a reference for the membrane separation for carbon capture. It is found that the concentration polarization significantly affects the membrane gas separation process. The two-dimensional distribution of concentration was obtained with concentration polarization. The concentration of CO2 on the retentate side becomes lower near the membrane due to permeation. Influences of pressure and permeability on the two-dimensional distribution of gas concentrations were also analyzed.