Removal of mixed VOCs of benzene, Toluene and xylene by a multistage corona discharge system

Abstract

The oxidation of mixed volatile organic compounds (VOCs) of benzene, tol-uene and xylene in non-thermal plasma corona discharge was investigated. An initial total VOCs concentration of 100 ppm and feed flow rate of 50.0 ml/min were firstly fixed to investigate the effects of an applied voltage and input frequency on VOCs conversion, power consumption and CO₂ and CO selectivities. For a single stage plasma system, under the optimum applied voltage of 8 kV and input frequency of 500 Hz, the system gave the high CO₂ selectivity with the low CO selectivity and the lowest power consumption. At the optimum operationable conditions, the effect of reactant feed flow rate and stage number were examined. The increase in reactant feed flow rate from 25 to 125 ml/min corresponding to the reduction of residence time from 0.92 to 0.19 s resulted in decreases in both of VOCs conversion and CO₂ selectivity from 97.7 to 63.9% and 84.0 to 22.6%, respectively while the CO selectivity was increased from 8.2 to 62.4%. An increase in stage number from one to two stages caused an increase in the total VOCs conversion approximately 100% especially for the feed flow rate of 100 ml/min.