Research On Dust Removal Mechanism And Technology Of Ceramic Membrane In High-temperature Coal-fired Flue Gas

In China,the primary energy structure is dominated by coal,and thermal power generation accounts for about 70% of the total electricity production.In the process of thermal power generation,the combustion of coal will produce a large amount of high-temperature flue gas.The traditional high-temperature flue gas dust removal method has a low removal rate of small particles due to the high temperature of coal flue gas,large amount of dust,and corrosive components in the gas.Existence,therefore,has a great impact on flue gas dust removal equipment.Ceramic membrane has the characteristics of high temperature resistance,corrosion resistance,cleaning resistance,and good mechanical strength.It has unique advantages in the application of high-temperature coal-fired flue gas dust removal.In China,the research and the industrial application of ceramic membrane high-temperature coal-fired flue gas dust removal technology are in the initial stage.According to flue gas conditions of high-temperature coal-fired power plants,this paper studies the low-cost and adaptable ceramic membrane high-temperature flue gas dust removal mechanism and technology to achieve efficient separation of dust and flue gas under high temperature conditions,especially the high-efficiency separation of fine particles.The main contents include:The basic properties of alumina,cordierite and mullite ceramic membranes were studied.The pore structure characteristics of the three ceramic membranes are analyzed by mercury intrusion method;the strength of the ceramic membrane is measured by the national standard method,and the results show that the alumina ceramic membrane has a higher porosity and a greater permeation flux during the dust removal process.The flue gas pressure loss is relatively low,and the three ceramic membranes exhibit good mechanical strength,which fully meets the requirements of coal-fired flue gas dust removal in power plants.According to the characteristics of high-temperature flue gas and actual working conditions of coal-fired power plants,a ceramic membrane high-temperature dust removal test device was designed and prepared.The device can simulate the performance of actual operating conditions(including pressure loss,filtration efficiency,flue gas flow,flow velocity,dust Concentration and particle size composition,etc.),to study and analyze the dust removal mechanism and process characteristics of different types of ceramic membranes.The simulation and comparative analysis results show that the dust removal device has good reliability and stability under the operating conditions of high temperature and high dust.On the self-made test device,the ceramic membrane flue gas dust removal technology and dust removal effect research,as well as the ceramic membrane dust removal and regeneration experiment research,analyzed the dust removal performance of different ceramic membranes and the influence of different process factors on the dust removal efficiency of ceramic membranes.The results show that the three ceramic membranes all show good dust removal performance,and the alumina ceramic membrane has the best dust removal performance;in the test temperature range(350-500℃),the temperature has little effect on the dust removal effect of the ceramic membrane;As the dust concentration increases,the efficiency of flue gas dust removal slightly increases;as the flue gas velocity increases,the dust removal efficiency decreases.Using the back-blowing cleaning method,under the conditions of back-blowing pressure of 0.7MPa and back-blowing time of 4s,the flux of the three ceramic membranes can almost be restored to more than 95%.Therefore,when the three ceramic membranes are used for high-temperature coal-fired flue gas dust removal,they can be used for multiple back-blowing and regeneration.From the comprehensive performance of dust removal efficiency,wear resistance strength and regeneration effect,the high temperature flue gas dust removal performance of alumina ceramic membrane is the best..