Experimental Study On NO_x And SO₂ In Sintering Flue Gas In Dielectric Barrier Discharge Oxidation

SO₂and NO_xare one of the main pollutants in the atmosphere,and their pollution prevention has received widespread attention from society.The sintering process is the link with the highest pollutant emissions in the steel production process,and how to reduce its SO₂and NO_xemissions has always been the focus of steel companies'research.Traditional sintering flue gas treatment methods can no longer meet the increasingly stringent emission requirements.Dielectric barrier discharge,as a plasma method with low energy consumption and good effect of removing nitrogen oxides and sulfur dioxide,has become a current research focus.In this paper,simulation and experiment methods are used to study the NO_xand SO₂in the oxidation gas of dielectric barrier discharge based on the simulated sintering flue gas.The effects of different discharge methods,power supply operating parameters,gas parameters,and additives on the oxidation of NO_xand SO₂were discussed.On this basis,unmodified activated carbon was coupled to compare the removal effects of NO and SO₂before and after oxidation.In order to provide reliable technical means and reasonable operating parameters for the ultra-clean emission of sintering flue gas.The main conclusions are as follows:(1)Through the simulation method,the gas flow rate that meets the temperature requirements of the sintering site is determined and the gas mixing tank with better mixing effect is designed at this flow rate.When the gas flow rate in the reactor is between 4-5L/min,the outlet temperature is 126?165?,which is in line with the temperature range of the sintering site;when the size of the star mixer is10mm*350mm,the gas outlet concentration is more uniform;(2)Power supply operating parameters and gas flow have a direct effect on the ionization effect in the reactor.When the power supply frequency is 8.5-9.6 k Hz and the power supply current is 0.6-1.2A,a stable plasma field can be formed.Under stable plasma field conditions,the higher the input power,the lower the gas flow rate and the better the ionization effect;(3)The oxidation effect of partial gas ionization on NO and SO₂is better than that of all gas ionization.All gas ionization methods carry out separate denitrification and separate desulfurization.The maximum oxidation rate of NO is 46.9%,and the maximum oxidation rate of SO₂is 36.3%;the partial gas ionization method ionizes20%of O₂and passes it into the simulated sintering flue gas.Up to 91.2%,the oxidation rate of SO2 is 37.3%;(4)The addition of ethylene can greatly improve the oxidation effect of NO under all ionization methods.Under the input power of 30W,after adding 2000ppm ethylene to the simulated sintering flue gas,the oxidation rate of NO can reach more than 95%.The presence of SO₂is not conducive to the oxidation of NO,which will reduce the O_xidation rate of NO and make the highest The peak power corresponding to the O_xidation rate increases,and the overall energy consumption of the reactor increases;(5)DBD coupled with activated carbon can effectively remove SO₂and NO_xin the sintering flue gas.The removal rate of SO₂before and after coupling is always higher than 90%;after the discharge oxidation of the DBD reactor,the removal rate of NOx increased from 4%to 76%.