Mechanism Study On The Generation Of Active Oxygen Free Radicals In Non-thermal Plasma

The non-thermal plasma contains much active free radicals,which are widely used in various fields of pollutant treatment.And it has the characteristics of good treatment effect and no secondary pollution.Diesel Particulate Filter can effectively filter the carbon in the diesel exhaust gas.But the smoke particles of DPF Filter need to be clear on a regular basis The active oxygen free radicals in the non-thermal plasma can oxidize the deposited carbon smoke particles in DPF at a lower temperature to achieve the regeneration of DPF.Most of the existing researches focus on the influence of external factors,such as discharge mode,on the concentration and treatment effect of active radical generation,but lack of understanding of the reaction mechanism of the active radical generation process.This paper conducts an in-depth study on how different discharge modes and working parameters affect the generation mechanism of oxyactive radicalIn this paper,based on CHEMKIN software,through the analysis of the main reaction paths of oxygen discharge reaction and the calculation and comparison of several typical reaction mechanisms,9 primitive reactions that can be used as the main reaction paths are obtained.On this basis,the reaction mechanism of oxygen discharge including 10 kinds of particles and 67 primitive reactions was constructed,and the reference value range of simulated conditions of dielectric barrier discharge and corona discharge was try to be given The corresponding experimental conditions were simulated to verify the oxygen reaction mechanism constructed in this paper,and the rationality of the reference range was also proved.At the same time,sensitivity analysis is carried out,and it is concluded that when selecting reaction mechanism in the simulation calculation,the electron collision reaction should be mainly considered in the case of high discharge voltage or high electron density such as corona discharge.If the temperature rise in the discharge space is to be considered,the reaction O-+O3?O2+O2-and so on should be taken into accountThe experimental study on the dielectric barrier discharge of O2/N2 mixture and the simulation calculation of the reaction mechanism with 10 kinds of particles and 14 primitive reactions were carried out.The results show that the optimal discharge voltage range for generating ozone is 2.0-2.3kV.Electron mole fraction is used to represent the relative size of electron density.The electron mole fraction around 0.001 can obtain a high concentration of O3.Moreover,the temperature rise in the discharge space is small,and the generation O3 concentration increases with the increase of electron temperature.If the N2 content in the mixture is higher than 50%,the O3 concentration will decrease with the increase of N2 content.The probability of an electron colliding with N2 and the effect of the reaction N+O2?NO+O on generating O3 concentration increases with the increase of N2 ratio The increase of temperature will lead to some side reactions,such as O+NO2?NO+O2 and NO+O3?NO2+O2,which are positively correlated with the rate constant,to intensify,which is not conducive to the generation of O,O3.