Rare Earth Tungsten Hot Electron Emission Characteristics Of High Temperature Electrostatic Precipitator Dust Charge

Coal-fired power technology is the main power generation technology of our country, so the dust has become one of the primary atmosphere pollutants. The rare-earth tungsten thermal emission style high-temperature electrostatic precipitation discussed in this paper is an innovative high-temperature flue gas purification method. The difference between the rare-earth tungsten thermal emission style high-temperature electrostatic precipitation and traditional ESP is that the former utilizes rare-earth tungsten cathode which emits electrons in high-temperature to make dust particles charged and then the charged particles are collected under the action of the electric filed. The key of the rare-earth tungsten thermal emission style high-temperature electrostatic precipitation is high-density and stable electrons emission in high-temperature flue gas. The characteristics of dust particles capturing thermal electrons influent the ESP efficiency, so the research on the dust particles charged characteristics appears especially important.In the earlier period, experiment has been carried with the rare-earth tungsten cathode under different temperatures and voltages.Experimental results show that the emission current density increases with voltage. The emission current density increases significantly with voltage, when the voltage arrives at 1000v. The temperature also has a significant impact on the emission current density. The emission current density increases with the temperature. When the temperature rise above 1000℃, the emission current density gathering increase with temperature.Based on the earlier period experiment results, this paper has established the rare-earth tungsten thermal emission style high-temperature electrostatic precipitation model. Dust particles charged model considers both of electric field charged and diffusion charged. Electric field distribution model considers the influence of the space charge on electric field distribution. Velocity distribution model divides into the axial velocity model and drive velocity model two parts. And the drive velocity considers the impact of secondary dust. Dust particles transport model considers the influence of electricity wind. The paper use the software of MATLAB to couple the above four sub-model in the second-order finite difference method. The dust particles charged characteristics have been simulated in different conditions and the simulation results have been discussed and analyzed which is consistent with the general laws of ESP. This provides basis for the further study on the rare-earth tungsten thermal emission style high-temperature electrostatic precipitation.