Optimizing SO2 Adsorption from Flue Gas Using Microporous Polypropylene Hollow Fiber Membrane Contactor

This study optimized the operational parameters of removing SO2 from flue gas via a polymeric hollow fiber membrane contactor (HFMC) using the response surface methodology (RSM). The distilled water and polypropylene hollow fibers were applied as the adsorbent and membrane material, respectively. Three independent variables were selected as experimental parameters: liquid flow rate, gas flow rate, and initial SO2 concentration. The initial SO2 concentration had a remarkable effect on SO2 removal efficiency. The optimal ratio of liquid-to-gas flow rate was found to be 0.25 to reach maximum separation efficiency (98.81%). The optimal value of the liquid flow rate was 33 l/h, and the optimal gas flow rate was 131 l/h. The effect of CO2 presence, module length, fibers number, temperature, and the adsorbent nature were also investigated under optimal values obtained for the ratio of liquid-to-gas flow rate. The findings indicated that CO2 presence in the flue gas slightly affects SO2 removal using water as an absorbent in HFCM. Furthermore, it was indicated that the SO2 removal efficiency was a function of the flue gas temperature and number of fibers: it decreased as the temperature rose from 20 to 50°C and the fiber numbers increased from 300 to 1000. This study offers a model to predict the efficiency of SO2 removal using HFMC under different conditions and provides the ground to further explore the industrial applications of this technology.