Research On The Technology Of Capturing Water Vapor In Flue Gas Of Thermal Power Plant By Composite Membrane

China is a country that has large coal reserves, therefore a coal dominated energy structure has been in place for a long time. Coal-fired power plants are the dominant in china, at same time the main water consumer, so water saving is becoming more and more crucial, both in arid regions and in water rich regions. The application of membrane technology for capturing water from flue gas is attractive due to the additional energy savings and the possible re-use of water. Membrane technology makes it possible to get selective removal of water vapor from flue gas streams and can produce water with high purities without additional heating. If for example20%of the water vapor from the flue gas stream of a coal fired power plant would be captured, the plant would been self-supporting from a process water pointe of view, so this research has important significance.The mechanisms of the gas permeation through porous films and homogeneous membrane are analyzed; the study on water vapor sorption and transport in polymer membranes is reviewed. After studying the properties of highly permeable and highly permeable and highly selective polymers for water vapor/nitrogen gas mixture, the PES hollow fiber membranes with a top layer of sulfonated poly(ether ether ketone)(SPEEK) is selected to make composite hollow fiber membranes to make test. After analyzing by SEM, we found the thickness of the active layer was uniform and it was combined well with the porous layer. The results of TG and DSC show that the composite hollow fiber membranes have good heat-durability and thermal stability. The sorption dynamic curves of water vapor in membranes were measured by the method of weight absorption and SAQ5000. The results indicate that the water absorption rate of membrane increased with the degree of sulfonation. After designing and building experimental platform, we investigated the effects of different SD of SPEEK, the flow rate of the sweeping gas and temperature on the performances of the membranes. From the research above it is show that it impossible to capturing water vapor from flue gas by using gas-gas separation composite hollow fiber membrane.