Preparation Of Low-Cost Coal Ash Ceramic Membrame And Study On Flue Gas Dehydration Performance

There is great potential to recover water vapor and waste heat from flue gas of coal-fired power plants.Ceramic membrane method is an effective way to recover water vapor and waste heat from flue gas,but commercial ceramic membrane is expensive.The fly ash output of power plant increases year by year and the effective utilization rate is only about 40%.According to the above problem,this paper from how to realize the efficient utilization of fly ash and recovery of waste heat and water vapor in the flue gas of power plant,the main contents include:using fly ash as the main raw material to the preparation of ceramic membrane and performance characterization and further applied to the water vapor and waste heat recovery from flue gas,and with the purchase of commercial α-Al2O3 ceramic membrane dehydration performance comparison.The preparation of low-cost coal ash ceramic membrane was carried out,using fly ash as main raw materials,adding sintering aid,binder and plasticizer,through fly ash pretreatment,ball milling,and furnishing.Tubular samples and flake samples were prepared by mixing,vacuuming,extrusion(sheet molding),room temperature drying and high temperature sintering,respectively.The mechanical properties of the fly ash-based ceramic membrane were optimized by changing the particle size and sintering temperature.Finally,the ball milling speed,ball milling time and sieve mesh were optimized to 300r/min,12h and 200 mesh,respectively,and the optimum sintering temperature is 1200℃.The production cost of the ceramic membrane is reduced due to the reduction in raw material cost and sintering temperature.Under the above optimized conditions,the mechanical strength of the self-made film was increased to 103MPa.Afterwards,the optimized self-made ceramic membrane and commercial ceramic membrane were characterized by electronic scanning electron microscopy(SEM),X-ray diffractometry(XRD),mechanical strength,mercury intrusion,abrasion resistance and corrosion resistance.The results show that:The pore size distribution of the self-made membrane is about 3μm,the porosity is 30.3%,the pore size distribution of the commercial membrane is about 2μm,and the porosity is 27.2%.The main crystal phase of the self-made membrane is anorthite and other heterophases,the crystal phase of the commercial membrane is corundum;the mechanical strength of the self-made film is 103MPa,and the mechanical strength of the commercial film is 90MPa;and the self-made film and the commercial film have strong wear resistance and corrosion resistance.The flue gas dehydration performance experiment was carried out.The results show that the recovery rate of self-made ceramic membrane is slightly higher than that of commercial ceramic membrane by about 0.3%,and the heat recovery efficiency is lower than that of commercial ceramic membrane by about 2%.Under different working conditions,the trends of the recovered water rate and heat recovery efficiency of the two membranes were basically the same.Based on the preparation cost,the self-made low-cost fly ash ceramic membrane has higher research and application value.