Experimental Research Of The Degradation Of Chlorobenzenes With Gliding Arc Plasma

Gliding arc discharge plasma is the cyclical swing non-equilibrium plasma at atmospheric pressure, which has a dual character of thermal and non-thermal plasma, more than80%of the input energy is used to excite the gas to produce high-energy electrons, ions and reactive free radicals, these active particles can prompt some reaction that can not occur under normal conditions or other difficult reactions to proceed, and the energy consumption is relatively small. Thus the non-equilibrium plasma technology is attracted wide attention in pollutant emission control and energy transforming. In this study, the gliding arc plasma coupling catalyst technology is employed to decomposition chlorobenzene pollutants. We selected hexachlorobenzene, pentachlorobenzene and1,2-dichlorobenzene as a typical representative of the chlorobenzenes to research its degradation rules, the primary chlorobenzenes degradation mechanism is proposed. The main research conclusions are as followed:(1) Basic studies on the gliding arc discharge plasma degradation of HCB. Parameters included the input voltage, flow rate, reaction background atmosphere were mainly discussed. The study found that gliding arc low-temperature plasma can decomposition hexachlorobenzene without a catalyst at ambient condition. In the air atmosphere, it is found that the degradation rates of HCB are70.53%and61.25%respectively in flat and rotating gliding arc discharge generator. Increasing of supply voltage and concentration of oxygen could improve the degradation rate of HCB. Increasing of total flow would reduce the staying time of reactant gas in plasma space and the energy density of plasma space, and then reduce the degradation rate of HCB. Existing flat, rotating and tornado gliding arc discharge reactor contrast indicated that rotating gliding arc reactor have a better environmental and economic efficiency.(2) Studies on the rotating gliding arc discharge plasma coupling TiO2catalyst degradation of chlorobenzenes. Discussed the TiO2catalyst’s effect on the process of gliding arc discharge plasma degradation of hexachlorobenzene,1,2-dichlorobenzene and PeCB. Especially, studies focused on the removal of the NOx produced during the process of gliding arc discharge by coupling TiO2catalyst were proceeded. The experiment indicated that TiO2catalyst can effectively promote the degradation reaction of chlorobenzenes. The degradation rate was increased obviously, and have a significantly effect on NOx emissions control, the amount of NOx in the exhaust dropped from800ppm to120ppm when add a TiO2catalyst, significantly reduced the NOx emissions during the discharge degradation process.(3) Studies on the gliding arc discharge plasma coupling TiO2catalyst degradation of chlorobenzenes’ mechanism. The primary degradation mechanism is roughly as followed:First, gliding arc discharge produce high-energy electrons, electrons collide with the background carrier gas molecules, then generating a large number of excited molecules, atoms and ions; and then, these active particles proceeding a collision reaction with chlorobenzene molecules, chlorobenzene molecules come into the dechlorination process; All intermediate product which generated in the above-described process continued to react with the reactive group, or react with each other. Thus, the chlorobenzene pollutants are decomposed completely.