Multiscale investigation for CO2 capture using membrane with AEEA: Significance of fluid flow and AEEA content to CO2 permeance

Abstract

Since it is energy efficient, CO2 capture by a membrane is a promising technique for mitigating an increase in CO2 in the atmosphere. This study considers a membrane containing 2-(2-aminoethylamino) ethanol (AEEA) because of its higher interaction performance than that of the other amines. It was assumed that the feed gas which is a mixture of CO2/He flows in a rectangular channel, and the membrane is placed at the bottom of the channel. Diffusional mass transfer of CO2 from feed gas flowing in the channel to the surface of the membrane was investigated. Incorporating the results for CO2 interaction with AEEA by density functional theory (DFT) calculation, the presented model can describe the effects of fluid (CO2/He mixed gas) flow over the surface of the membrane and the AEEA content of the membrane on the gas transmission rate, i.e. the CO2 permeance. Theoretical results reveal that the CO2 permeance increases as the mean flow velocity increases. The CO2 permeance also depends on the AEEA content of the membrane, i.e. the CO2 permeance increases with increased AEEA content. It was also found that predicted CO2 permeance has a range from 10−8 to 10−7 m3(STP)m−2s−1Pa−1 which is much larger than those obtained in the experiments using the polyamidoamine (PAMAM) dendrimer/polymer hybrid membrane, i.e. 10−10 to 10−9 m3(STP)m−2s−1Pa−1, indicating that AEEA can capture CO2 from the CO2/He mixed gas much more efficiently than the other amines.