Effect of flow and module configuration on SO2 absorption by using membrane contactors

Sulfur dioxide (SO2) emissions lead to negative environmental impacts and it is considered as an indicator for the larger group of gaseous sulfur oxides (SOx) in the air. In this paper, the dimethylamine (DMA) solution was used as the absorbent in a alpha-Al2O3 hollow fiber membrane contactor that is operated under several conditions of gas velocity, liquid velocity, and 290 K operating temperature. The effects of gas and liquid phase properties and module configuration on SO2 absorption efficiency in the hollow fiber membrane contactor were investigated. Simulation results showed that the changes of gas phase velocity, liquid phase velocity, and concentration have great influences on the absorption efficiency of SO2. An increase of the gas flow rate decreases the SO2 absorption efficiency, while an increase of the liquid flow rate has the opposite effect, increasing the efficiency. Because gas in the membrane module stays for a longer time, more absorption time promotes the gas and liquid reaction. However, the changes of the volume fraction of SO2 in the mixed gas are not significant to SO2 absorption. The simulation model could provide guidelines for selecting suitable fluid properties during the SO2 absorption process in a hollow fiber membrane contactor.