Research On Removal Of Volatile Organic Compounds By DBD Nonthermal Plasma

With the development of society,volatile organic compounds(VOCs)have become an important pollutant in the atmosphere.Coal-fired power plant is a large producer of VOCs emissions,so the study on the removal of VOCs in coal-fired power plant has become a hot topic in today’s society.Low temperature plasma removing VOCs has simple operation,less by-products generation,but if you want to can be extended to the field of engineering application,there are many questions we need to be urgently addressed to emissions from coal-fired power plant flue gas containing O2,SO2 and water,and to explore different atmosphere and temperature have any effect on removal of VOCs,understand the ultimate destination for VOCs,reducing the generation of organic byproduct.In view of the above problems,this paper adopts dielectric barrier discharge(DBD)to carry out the following research:(1)The effects of different variables(O2,SO2,water,temperature)on toluene removal efficiency were investigated under different energy input densities.It was found that the higher the energy input density,the better the removal effect of toluene.Low concentration of oxygen is ionized into active oxygen atoms,will promote the removal of toluene;The existence of SO2 will compete with toluene molecules for charged particles,leading to the reduction of VOCs removal efficiency;However,the existence of water vapor can remove VOCs in many ways.When the water content is low,the collision between high-energy OH particles and VOCs molecules is generated,which improves the removal efficiency.When the water content is high,the presence of water will inhibit the discharge and quench high-energy electrons,which also leads to the reduction of the removal efficiency of toluene.The influence of temperature was explored,and the removal efficiency of simulated flue gas components was explored at different temperatures.The increase of temperature would improve the activation energy of the system,so that it could reach the required activation energy more quickly and promote the reaction.And the reaction mechanism was briefly explored.(2)Under the condition of containing O2,after discharge removal of toluene,CO and CO2 into almost all use Fourier infrared spectrometer(FTIR)of different concentrations of CO and CO2 generated atmosphere has carried on the quantitative analysis,analyzed the different variables(O2,SO2,water,temperature)influence on toluene carbon balance,to explore the fate of carbon atoms,make after removing more harmless.After the reaction,some of the by-products will cool down and form concentrated materials attached to the wall of the tube.In the atmosphere of pure nitrogen,the concentrated materials on the wall of the tube have a higher carbon balance.In the atmosphere containing oxygen,the carbon balance of CO and CO2 above 300J/L accounts for more than 90%;And SO2 and water vapor in the carbon balance of CO and CO2 atmosphere will eventually account for more than 80%,almost no by-product generated under 350℃,the temperature rise will increase the conversion of system field,and the activation energy required will provide molecular reactions are more likely to happen,so the temperature rise will accelerate the removal of toluene,and help CO to CO2 conversion.(3)The VOCs gas in different atmosphere and temperature was adsorbed by TENAX adsorption tube.After adsorption,the adsorption tube was put into thermal analyzer for desorption,and then entered into GCMS to analyze the gas phase by-products after reaction.The experimental study found that the content of organic by-products was very small when containing oxygen,benzaldehyde was the main by-product,and the formation mechanism of the by-product was summarized.However,in the pure nitrogen atmosphere,the removed toluene is mainly converted to nitriles,and most of it adheres to the wall of the tube.(4)To explore the removal effect,carbon balance and by-product formation of benzene mixtures(benzene,toluene,m-xylene)with different gas compositions at high energy density(95J/L)and low energy density(400J/L).This is due to the presence of methyl groups,which are more likely to break.