Experimental Study On Wet Electrostatic Precipitator Technology In Front Of Gas Holder

Emissions of fine particulate matter from industry are still a problem that plagues the world.While coal-fired power plants are gradually becoming a key area of industrial flue gas treatment,particulate matter produced by the steel smelting industry also needs to be addressed urgently.Due to the acid gas such as HCl entrained in blast furnace gas,wet electrostatic precipitator technology has always been an effective means to control the dust concentration of gas in the field of blast furnace gas power generation,and most smelters choose to set the wet electrostatic precipitator behind the gas tank for gas purification.However,when the gas cannot meet the requirements of entering the gas holder due to excessive oxygen content and high dust concentration,the gas can only be discharged,causing environmental pollution.Therefore,this study proposes to set a wet electrostatic precipitator in front of the gas tank to reduce the dust concentration of the gas and improve the gas recovery rate.In order to further enhance the removal efficiency of fine particles in blast furnace dust by wet electrostatic precipitator,this study proposes a method of adding chemical agglomerates and surfactants in the dust removal process to achieve the ’growth’of fine particles.By studying the influence of water pressure,electric field,and wind speed on corona discharge and droplet size,the optimum conditions for a wet electrostatic precipitator to capture blast furnace dust are obtained.Firstly,the particle size distribution,microscopic morphology and elemental components of blast furnace dust were measured and analyzed.Secondly,the effects of water pressure,wind speed,chemical coagulator,corona line shape,nozzle type,and air humidity on corona discharge performance and droplet size were studied.The experimental results show that:(1)Blast furnace dust is mostly irregular particles with a median diameter of 6.754 μm,mainly containing metallic elements such as Ca,Na,Fe and Al,and inorganic elements such as Si and C.(2)In the corona discharge performance study,the best corona discharge performance was achieved when the water pressure was0.5 MPa,and the wind speed was 1.1 m/s.Polyacrylamide(PAM),konjac glucomannan(KGM),k-carrageenan(KC),xanthan gum(XTG),and kieselguhr 5 chemical agglomeration agent in KC discharge effect is the best,and XTG discharge effect is the worst.surfactant Dodecyl trimethyl ammonium chloride(DTAC),sodium dodecyl sulfate(SDS),and Triton X-100(TX-100)in DTAC discharge effect is the best,TX-100 discharge effect is the worst.when the corona line for the fishbone needle line,1/4 solid conical nozzle corresponding to the discharge effect is the best,when the corona line for the BS barbed line,spiral Corona discharge performance under the nozzle conditions is optimal.In addition,the corona discharge performance with the increase in air humidity is better,the air humidity of 80% corresponding to the voltametric characteristic curve is more advantageous.(3)In the coagulation performance study,the agglomeration effect of XTG was the best among the five agglomerates of PAM,KC,KGM,XTG,and kieselguhr,with the dust D90 of 114.9 μm and the XTG concentration of 15 mg/L.The agglomeration effect of DTAC was the most obvious among DTAC,SDS,and TX-100.When XTG,kieselguhr,KGM,and DTAC synergistic action,respectively,KGM/DTAC agglomeration effect is the best,the concentration of the two were 10 mg/L,9 mg/L.(4)In the droplet particle size study,the higher the water pressure the smaller the droplet particle size,spiral,1/8 hollow cone,3/8 solid cone,1/8 solid cone,1/4 solid cone in five nozzles under the same water pressure,1/4 solid cone spray droplet particle size is the smallest;after adding PAM,XTG,TX-100,in the same water pressure XTG corresponding droplet particle size is the largest.(5)With 0.5 MPa water pressure,1.1 m/s air velocity,fishbone needle line,and 1/4 solid cone nozzle,XTG/DTAC synergistic action has the highest dust removal efficiency of 97.82%.Through the study of corona discharge,chemical coagulation,droplet atomization,and the experiment of blast furnace dust capture performance,the optimum working conditions of wet electrostatic precipitator in removing blast furnace dust are obtained.In addition,the addition of a chemical agglomeration agent can significantly improve the removal efficiency of blast furnace dust,and the optimal concentration is determined by considering the cost.This study can provide a reference for the purification of blast furnace gas in industrial practice.