Numerical Simulation And Study Of Gas-solid Two-phase Flow In Flexible Membrane High Temperature Dust Filter

With the rapid development of urban industrialization and the continuous growth of energy demand,the emission of pollutants such as dust from coal-fired power plants is increasing,which has caused great harm to human health.In recent years,due to China's high attention to environmental protection,the emission standards for dust particles in thermal power plants have become increasingly strict.Bag dust collectors have been widely used in dust removal equipment of coal-fired power plants because of their high dust removal efficiency,good dust capture effect on small perticle size,and high-temperature dust-containing flue gas.However,the dust collector often processes high-temperature flue gas during operation.The high-temperature dust-containing flue gas will cause blockage,wear and poisoning failure of the SCR catalyst of the denitrification device.There are also problems such as uneven flow field distribution,high running resistance,and short mission life of the filter bag.It is not only time-consuming and labor-intensive to study the above problems through test methods.In this paper,the flexible membrane high-temperature dust collector of 300t/h coal-fired power plant in Shanxi Province was taken as the research object.The computational fluid dynamics(CFD)software Fluent was used to simulate the numerical simulation and structure optimization.The different filtering wind speeds were studied in the high-temperature dust collector.The influence of flow field uniformity is proposed.The optimization scheme of adding trapezoidal baffle in the ash bucket is proposed,and the pulse blast cleaning process of high temperature dust collector is simulated.The simulation results show that with the greater the filtering wind speed,the stronger the inlet jet action,causing the airflow to severely wash the bottom of the filter bag.The unevenness of the velocity distribution in the high-temperature dust collector is more obvious,the pressure loss is increased,and the air bag distribution coefficient of the filter bag is presented.The distribution state of “two big,medium small”;after the trapezoidal baffle is added for optimization,the inlet jet phenomenon is weakened,the erosion of the dust particles on the rear wall filter bag is alleviated,the airflow distribution is improved,and the pressure loss is reduced by about 55% before optimization,effectively reducing the operating energy consumption of the precipitator;as the blowing time,the blowing pressure and the blowing diameter increase,the expansion range of the blowing airflow in the fil ter bag increases,and the airflow speed increases accordingly.It is beneficial to improve the cleaning effect of the filter bag,but after exceeding a certain range,it is easy to cause problems such as increased consumption of compressed air,shortened life of the filter bag,and increased operating cost of the device.The simulation results in this paper effectively improve the uniformity of gas-solid two-phase flow in high-temperature bag filter,effectively reduce the running resistance of the dust collector,and have important reference significance and application value for promoting the theoretical and technological progress of high-temperature dust collector.