CO2 capture in a hollow fiber membrane contactor coupled with ionic liquid: Influence of membrane wetting and process parameters

Abstract

The present work demonstrates the potential of coupling ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO4]) and hollow fiber membrane contactors for post-combustion CO2 capture. CO2 absorption experiments in counter-current configuration were carried out, followed by a comprehensive two-dimensional dynamic modeling based on steady state and pseudo-steady state operating modes. The model considers the level of wetting of porous hollow fibers. An overall mass transfer coefficient of 3.99 · 10−5 m s−1 and CO2 flux 6.1 · 10−5 mol m−2 s−1 were obtained for 100 ml min−1 of gas flowing inside the fibers. The model predicted the effects of membrane wetting, porosity, tortuosity, module length, fiber inner diameter, gas and absorbent flow rates. Membrane wetting has a noteworthy effect on CO2 capture efficiency. A smaller amount of wetting can cause a huge resistance in CO2 transport through the membrane. The separation efficiency was enhanced by using membranes with high porosity and low tortuosity and decreased by enhancing the gas flow rate and absorbent flow rate reduction. CO2 capture is enhanced by increasing module length and reduction of inner diameter of fibers.