Simulation of Carbon Dioxide Absorption in a Hollow Fiber Membrane Contactor Under Non-Isothermal Conditions.

CO2 capture by membrane gas absorption technology has been considered a promising alternative to mitigate or stabilize atmospheric CO2 concentrations. The non-isothermal nature of the CO2 absorption process in hollow fiber membrane contactors is a critical factor that significantly influences CO2 removal performance. In the present study, a non-isothermal mathematical model and a two-dimensional computational simulation were carried out to evaluate the CO2 separation by three typical absorbents in a polyvinylidene fluoride hollow fiber membrane contactor under non-wetting operation mode. The simulation results exhibited good matching with the published experimental data with the deviations in the range of lower than 5%, which validated the reliability of the developed numerical model. A significant temperature increase ranging from 2 to 15 K was observed along the length of the hollow fiber membrane contactor, which further facilitated the absorption and reaction process in this study. The results showed that potassium glycinate exhibited the highest absorption capacity, followed by monoethanolamine and 1-ethyl-3-methylimidazolium. In addition, the mass transfer could be enhanced by increasing the liquid flow rate, absorbent concentration, module length, and membrane porosity, while increasing the gas velocity and CO2 inlet concentration were unfavorable for the CO2 removal process.