Rate based modeling for CO2 absorption using monoethanolamine solution in a hollow fiber membrane contactor

Abstract

This work presents a rate based model to estimate the performance of CO2 absorption by monoethanolamine (MEA) solution using a hollow fiber membrane contactor. The predicted CO2 fluxes were validated with the experimental data of both polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) membranes from the literature. The simulation results of the PTFE membrane showed that the CO2 flux could be predicted by the rate based model with a deviation less than 4% for a non-wetted mode of operation. For the PVDF membrane, the model predicted the CO2 fluxes fairly well under partially-wetted mode of operation. The simulated concentration profiles in both the gas and liquid phases, as well as the liquid temperature profile of PTFE membrane, corresponded well with the experimental data. A study of parameter sensitivity analysis revealed that the proposed model is most sensitive to Henry's constant and when the reaction regime between CO2 and MEA changes from intermediate fast-instantaneous to instantaneous, when the membrane is 20% wetted. A comparison between the CO2 fluxes of the non-wetted and partially wetted modes showed that the increase of CO2 flux in the non-wetted mode with an increasing gas composition and liquid temperature is more significant than that of the partially wetted mode.