Experimental Study On The Transport Performance Of Water Vapor From Flue Gas Of Power Plant In Porous Ceramic Membrane

Thermal power generation is the largest industrial water withdrawal industry,power plant boiler flue gas contains a lot of water vapor.By recovering water vapor from power plant boiler flue gas,it not only can be used to make up water for boiler to save water resources,but also can recover latent heat of vaporization of flue gas and sensible heat of flue gas to improve boiler efficiency.In this paper,the characteristics of heat and mass transfer of flue gas in porous ceramic membranes were analyzed.The principle of heat and mass transfer based on the principle of multi-layer adsorption and capillary condensation and the condensation-permeation principle were proposed respectively.In the first case,when steam passes through the membrane pores,multilayer adsorption occurs in the membrane pores first,and when the condensation component reaches a certain pressure,capillary condensation occurs and then permeates through the membrane.In the second case,when the temperature of the membrane surface in contact with the gas is lower than the water dew point temperature of the mixed gas,the water vapor condenses on the membrane surface to form a water film,which then permeates through the membrane pores.In order to verify the theory put forward above,this paper designed and built an experimental device for recovering water vapor from flue gas by using porous ceramic membrane.Water recovery,heat recovery,and SO2 permeability were measured by controlling flue gas temperature,flue gas flow,relative pressure of water vapor in flue gas,cooling water flow,and cooling water temperature.According to the experimental results,it is concluded that the permeability of S02 is very low,and the recovery of water through the mechanism of condensation and infiltration can still obtain higher water quality.Under the experimental conditions,the experimental results are consistent with the results of theoretical analysis,indicating that the proposed porous ceramic membrane hydrothermal recovery mechanism is correct.Through theoretical analysis and experimental verification,it is found that it is feasible to recover water vapor from flue gas through porous ceramic membrane.By studying the heat and mass transfer characteristics of porous ceramic membrane,it can help to recover the water vapor and latent heat in the boiler flue gas.