Effects of coexistent gaseous components and fine particles in the flue gas on CO2 separation by flat-sheet polysulfone membranes

Abstract

Nowadays, membrane separation technology has been one of the most effective technologies for CO2 capture. The coexistent components in the actual flue gas, such as water vapor, SO2, O2 and fine particles, may have a significant influence on the separation performance of polymeric membranes for CO2 capture. In order to comprehensively and systematically investigate the effects of these components, a series of lab-scale separation experiments for CO2 capture were conducted in the simulation test-bed with the commercially available flat-sheet polysulfone (PSF) membranes. At first, the operation conditions were optimized for CO2 separation by PSF membranes and the best operation conditions were 0.4MPa as the feed gas pressure, 400L/h as the residual gas flow rate and 50°C as the feed gas temperature. Then, the PSF membrane performances on CO2 separation in the presence of water vapor, SO2, O2 and fine particles in the actual flue gas were studied. It was found that water vapor promotes the CO2 separation performance of PSF membranes by a net increase of the CO2/N2 selectivity, CO2 permeability and CO2 enrichment efficiency. O2 slightly inhibits the CO2 separation performance, while the effect of SO2 is negligible. The gypsum fine particles significantly deteriorate CO2 separation performance of PSF membranes, which mainly results from the occupation of the effective membrane area, the increase of the mass transfer resistance and the partial adsorption of the gases by the gypsum fine particles deposited on the membranes.