Influence of the Membrane Module Geometry on SO2 Removal: A Numerical Study

SO2 emissions to the atmosphere result in acid rain, which is a key issue for the environment. Membrane gas absorption is a novel approach to minimize the SO2 emissions to the atmosphere. A comprehensive mass transfer model considering the nonwetting mode is proposed to observe the SO2 absorption performance. A physical solvent of H2O and a chemical solvent of N,N-dimethylaniline are utilized as the aqueous absorbents. The calculated results are verified against the available experimental data derived from two different modules, demonstrating a good consistency. The effects of the inside membrane diameter, membrane thickness, porosity, fiber length, number of fibers, and inside module diameter on removal of SO2 were simulated. The results show that an improvement in the absorption performance can be achieved by increasing the number of fibers and porosity, and decreasing the membrane thickness and inner contactor radius. Furthermore, a longer module length (corresponding to a higher gasliquid contact area) results in a sharp decline of the SO2 removal efficiency, while the SO2 flux increases. Finally, the model provides guidelines for the selection of optimum module parameters for SO2 absorption.