Membrane-Based SO2 Removal Using a Hollow Fiber Membrane Process for Flue Gas Treatment

Growing environmental concerns and stringent air pollution regulations have intensified the need for efficient gas separation technologies to mitigate hazardous industrial emissions. Flue gas emissions from power generation and manufacturing industries are a major source of sulfur dioxide (SO2), contributing to acid rain and environmental degradation. Membrane separation processes have emerged as an energy-efficient and sustainable solution for SO2 removal. Particularly, hollow fiber membranes (HFMs) offer significant advantages due to their high surface area-to-volume ratio, enabling efficient mass transfer and compact system configurations. This study focuses on designing and fabricating a pilot-scale poly(ether sulfone) (PES) hollow fiber membrane coated with cellulose acetate (CA) for SO2 removal from flue gas. The composite membrane was developed by coating a cellulose acetate (CA) layer onto PES HFMs via a solution-based continuous coating method. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) confirmed the presence and uniformity of the CA coating. Gas permeance measurements demonstrated that the pressure differential across the membrane influences membrane performance. The membrane's effectiveness was evaluated using emissions from an LPG boiler under varying operating conditions, revealing a high SO2 removal efficiency. A mixed-gas separation experiment assessed SO2 removal efficiency and the associated CO2 loss ratio. The results indicated a positive correlation between SO2 removal efficiency and the loss ratios of other gas components, driven by their inherent permeance characteristics, with SO2 permeance reaching up to 702.4 GPU. Under optimized conditions, the membrane achieved over 91% SO2 removal efficiency while maintaining the CO2 loss ratio. This study confirms the feasibility of using pilot-scale HFMs for SO2 removal from flue gas, highlighting their potential for industrial gas separation and sustainable pollution control.