Application of Water-Swollen Thin-Film Composite Membrane in Flue Gas Purification

摘要

A water-swollen thin-film composite membrane, which was a reverse osmosis membrane with a thin polyamide layer, was used to separate a model mixture of N-2, CO2, and SO2. The polyamide swells with water, and thus, becomes more permeable to polar gases. The flue gas contains water vapor, which must be removed before it is subjected to SO2 removal. Here moisture is employed to keep the membrane swollen. Using the model mixture, the humidified feed stream is brought to the membrane, where it is cooled below the dew point, so that water condenses on the membrane to keep the polyamide swollen. The membrane showed high CO2 and SO2 permeance, but low selectivity, so it could be applied to separate these two gases from N-2, and thus, is suitable for flue gas purification.