Research On Dust Removal Characteristics Of Electrostatic Precipitator Based On Cathode Discharge Of High Voltage Pulse Power Supply

As an international problem in the fields of power,metallurgy and chemical industry,the problem of dust removal has attracted more and more attention.High-voltage electrostatic precipitators have been widely used because of their long development time,easy maintenance,and high reliability.Among them,electrostatic precipitators based on high-voltage pulse power cathode discharge are considered to be one of the most promising technologies.In order to further understand the actual purification effect of pulse power electrostatic precipitator on flue gas and optimize the dust removal process,for the actual electrostatic dust removal system of a domestic coal-fired power plant,pulse power supply and high frequency power supply are used to replace the original DC power supply through dynamic operation test.And on-site test and analysis to obtain the test results of power consumption and dust removal efficiency of electrostatic precipitator under different power supply operation modes.The test and research results show that the pulse power supply is used as the power source of the electrostatic precipitator of the power plant,and the mass concentration of the flue gas at the outlet of the precipitator is reduced from 42.8mg/Nm³ to 20mg/Nm³.The dust removal effect is significantly improved;99.91%,99.89%,99.79%and 99.82%,all in line with the requirements of the electrostatic precipitator design value of 99.78%;when the unit is fully loaded and the dust removal efficiency is basically the same,compared with the high-frequency power supply,the pulse power consumption is significant reduce.Based on theoretical calculations,further discussion is given to the classification dust removal characteristics of high-voltage pulse power electrostatic precipitators.Theoretical analysis shows that after the pulse power supply and the high-frequency power supply replace the traditional power-frequency DC power supply,the ion concentration value in the charged area reaches 10¹⁴/m3,or even 10¹⁵/m3,which is higher than that of the traditional power-frequency DC power supply electrostatic precipitator.Out of 1-2 orders of magnitude,it can significantly increase the dust charge and improve the dust removal efficiency.We designed and built a set of low-work function cathode pulse discharge and dust removal experiment system,prepared different types and different specifications of rare earth tungsten cathode,and carried out high voltage pulse discharge experiment.The results show that under normal temperature and air environment,when the voltage is low?below 15 k V?,there is no obvious gas discharge.As the voltage rises to a certain critical value Vc,a severe corona discharge phenomenon begins to occur.The value of Vc and the cathode The work function of the material is positively correlated.The theoretical analysis of the dust removal characteristics found that with different rare earth tungsten materials as the cathode,the change trend of the dust removal characteristics of the dust collector is basically the same.Although there is a certain difference in the size of the dust removal efficiency,no matter which rare earth tungsten material is used as the cathode,for the established dust removal device and specific working conditions,its collection efficiency for PM_2.5 can reach more than 95%.The flue gas flow has a great influence on the dust removal efficiency.When the flue gas flow is increased from 1.5 m³/h to 16.5 m³/h,the dust removal efficiency drops from more than 95%to less than 30%.