Experimental Research On The Influence Of Chemical Condensation And On The Performance Of Wet Electrostatic Precipitator

The dominant position of coal doesn’t change in Chinese energy industry.When the coal burning,a large amount of particulate matters（PM）are emitted,which not only do harm to the human and environment,but also collect difficultly.The combustion in the power industry was close to 50%of the total.In 2019,the power industry consumed 2.29billion tons of coal.Coal-fired power plants have been a key area of industrial flue gas dust removal.Electrostatic precipitator（ESP）technology is the main technology in the current dust removal technology at home and abroad.The wet electrostatic precipitator（WESP）has many advantages,such as high dust collection efficiency,low resistance loss during operation,large amount of flue gas treatment and so on.Conventional electrostatic precipitator technology has low collection efficiency of PM10 and PM2.5.It is difficult to achieve ultra-low emission standards.The chemical coagulation technology is applied to the wet electrostatic precipitator.Because it can improve the collection efficiency and the cost is not high.Firstly,the particle size distribution,microscopic morphology and chemical composition of dust from coal-fired power plant are measured and analyzed.Secondly,the influence of nozzle type,water pressure,chemical coagulant and other factors on the atomization and corona discharge performance are studied.Then,the influence of the water mist charging and chemical coagulation on the dust coagulation effect was analyzed.Finally,the best collection efficiency of the conditions was carried out The results show that:（1）Coal-fired power plant dust is mostly regular spherical particles with median diameter of 18.15μm,composed of oxygenium,silicon,aluminum and other elements.（2）When the type of nozzle is selected to 1/4 solid cone,the water pressure is 0.7 MPa,and the surfactant is benzalkonium chloride（1227）,the median diameter of the droplets is the smallest.It is 106.03μm;When the type of nozzle is selected to 1/4 solid cone,the water pressure is 0.5 MPa,and the added surfactant is benzalkonium chloride,the corona discharge performance is the best.When the secondary voltage is 40 kV,the corresponding secondary current is 98 mA.（3）In the water mist charging and coagulation experiment,when the type of nozzle is selected to 1/4 solid cone,the wind speed of the electric field is 1.0 m/s,the water pressure is 0.5 MPa,and the voltage is 40 kV.The median diameter of dust is 31.75μm;In the chemical coagulation experiment,when the type of nozzle is selected to 1/4 solid cone,the wind speed of the electric field is 1.0 m/s,the water pressure is 0.5 MPa,and the voltage is 40 kV,the xanthan gum（XTG）solution is 1.0×10^-2g/L,the benzalkonium chloride solution is 0.5×10^-2g/L,the best coagulation effect is obtained.The median diameter of the dust is 55.70μm.（4）When the type of the nozzle is selected to 1/4 solid cone,set the wind speed of the electric field to 1.0 m/s,the water pressure is 0.5 MPa,the voltage is 40 kV,the concentration of XTG is 1.0×10^-2g/L,and the concentration of benzalkonium chloride is 0.5×10^-2g/L,the dust collection efficiency is the highest,the dust collection efficiency of coal-fired power plants can reach98.80%,and the collection efficiency of gypsum dust can reach 98.61%.The atomization effect,corona discharge performance of chemical coagulation on wet electrostatic precipitator and the coagulation effect were researched.The conditions for the highest collection efficiency of coal-fired power plant dust and gypsum dust have been found.It is proved that the application of chemical coagulation in the wet electrostatic precipitator can improve the collection efficiency.This research provides a reference for industrial applications.