Experimental and Numerical Analysis for Improving CO₂ Mass Transfer Performance of Blended Solvents in Hollow Fiber Membrane Contactors

Abstract

In this study, the COMSOL Multiphysics simulation software, based on the finite element analysis method, was used to numerically simulate the CO2 mass transfer process in laminar flow and turbulent flow in a hollow fiber membrane contactor. The established simulation model was verified by comparing the simulated value of the CO2 absorption flux in a diethylaminoethanol/3-methylaminopropylamine mixed solution with the actual process value. It was found that the laminar flow model with 5% membrane wettability is in good agreement with the experimental value, with an average relative error of only 2.64%, indicating that the actual degree of membrane wetting during the experiment is indeed 5%. In addition, the effects of operating parameters and membrane process optimization on the velocity field, concentration field, and mass transfer process in the membrane contactor were studied taking into consideration both the diffusion effect and the convection effect. From the analysis of the simulation results, it can be seen that the membrane-phase resistance dominates when the membrane is wetted, and the optimization of the operating parameters under these conditions makes limited improvement in the mass transfer performance. Given the inevitability of membrane wetting in practical long-term applications, increasing the degree of fluid turbulence and the series connection of multistage membrane modules are both good methods to promote mass transfer.