Study Of Temperature Characteristic And Reactive Species In DBD By Optical Emission Spectroscopy

In recent years, air pollution had became more and more serious, while people appeal for better living environment became more strong, which urged the government enact more severe environment policy, aimd to have a progress on pollution control. As a main consistent of air pollution, it is urgent to control NOX emission. NOx emitted from coal-combustion plants account for a large proportion in total NOx emission, so it is important to remove the NOx emitted by coal-combustion plants. Pre-oxidation technology is a promising method which can cooperate with existing desulfurization and denitrification plant to realize multi-pollutants simultaneous removal.Dielectric barrier discharge (DBD) is one of non-thermal plasma, can be used as pre-oxidation. DBD has many advantages, especially for its stability and can produce plasma of large area, have been researched widely.In this research, the physical and chemical characters of NO conversion process in DBD discharge was studied by Optical Emission Spectroscopy (OES). Obtained one-dimensional distribution of NO(A2∑+�'X2П,0-3,1-4)、N2(C3Пu�'B3Пg,0�'0) and OH(A2∑+�'X2П,0�'0) with high resolution.By simulated emission spectrum of Ar atom spectrum,N2(C3Пu�'B3Пg) and NO(A2∑+�'X2П.0-3,1-4), obtained electron temperature, vibrational temperature and gas temperature in DBD area. When AC voltage range in16-19kV, electron temperature was about10000K; vibrational temperature range from1300K to1800K; Gas temperature can be influenced by voltage、O2concentration relative humidity and flow rate, but the temperature mainly range in310-360K, which was much lower than electron temperature and vibrational temperature.The influence of voltage、flow rate、O2concentration and Ar concentration on NO(A2∑+�'X2П,0-3,1-4) and N2(C3Пu�'B3Пg,0�'0) emission intensity has been researched, energy input by discharge and N2(A3∑+) molecules had a important effecf on NO and N2emission intensity. Also, H2O molecules was added in gas, emission intensity of OH reachs maximum when RH at20%; O2concentration and discharge voltage have the opposite effect on the emission intensity of OH; the influence of relative humidity on NO(A2∑+�'X2П,0-3,1-4) and N2(C3Пu�'B3Пg,0�'0) emission intensity was observed; the influence of NO concentration on NO(A2∑+�'X2П,0-3,1-4) and OH(A2∑+�'X2П,0�'0) emission intensity was also observed, which confirmed OH radicals can oxidize NO molecules efficiently.