A Numerical Study on Removal of CO2 by 2-(tert-Butylamino) Ethanol in a Hollow Fiber Membrane Contactor

Abstract

Using a hollow fiber membrane contactor to absorb carbon dioxide from natural gas has been a widely studied decarbonization technology in recent years. In this study, 2-(tert-butylamino) ethanol (TBAE), as a new absorbent, was used in hollow fiber membrane contactors to separate CO₂ from CO₂/CH₄ gas mixtures. A two-dimensional hollow fiber membrane contactor model was established using COMSOL Multiphysics. The changes of membrane specifications and operating conditions during the absorption of CO₂ by TBAE, ethanolamine (MEA), ethyl-ethanolamine (EEA), and ethylenediamine (EDA) were calculated and studied using parallel countercurrent flow, absorbent tube side, and gas shell side. The research results show that the decarbonization performance from large to small is MEA > TBAE > EDA > EEA. The removal rate increased with the increase of the inner diameter of the membrane, the flow rate of the absorbent, and the concentration of the absorbent. Increasing the gas flow rate and the volume fraction of CO₂ in the feed gas resulted in the decrease of the decarbonization rate, and the mass transfer rate increased with the increase of the absorbent flow rate and the volume fraction of CO₂ in the feed gas. The decarbonization effect similar to that of MEA can be achieved using the TBAE absorbent by changing the specification of the membrane, such as increasing the inner diameter of the membrane wire or increasing the concentration of the absorbent.