Performance evaluation and optimization of hollow fiber membrane contactors for carbon dioxide absorption: a comparative study of ammonia, ethanolamine, and diethanolamine solvents

Membrane absorption is an emerging technology that amalgamates the merits of chemical absorption and membrane separation. However, the pivotal choice of solvent profoundly influences the overall performance of the membrane contactor. In this paper, a robust two-dimensional (2D) steady-state non-wetting mathematical and physical model of a hollow fiber membrane contactor (HFMC) was established. COMSOL software was used to solve the model equation of the membrane contactor. The impacts of ammonia, ethanolamine (MEA) and diethanolamine (DEA) on carbon dioxide absorption under different operating conditions and membrane geometry properties were simulated and compared. Results showed that the utilization of NH3 as the solvent in HFMC showcases performance akin to that of MEA, a substantial advantage over DEA. Notably, the performance disparity between ammonia and MEA might alter significantly in response to varying operating parameters. For instance, the CO2 removal performance of HFMC using aqueous ammonia surpasses that of MEA when the CO2 volume fraction exceeds 19%. Moreover, hollow fibers featuring larger inner diameters and lengths endow a heightened effective mass-transfer area, thereby facilitating superior carbon dioxide removal performance.