SF6 abatement in a packed bed plasma reactor: Role of zirconia size and optimization using RSM

Abstract

This work describes plasma destruction of SF6 in a zirconia (ZrO2) packed bed plasma reactor (PBR). Electric signals, equivalent parameters, emission spectra and degradation results have been utilized to evaluate the influence of ZrO2 size on PBR discharge characteristics and SF6 degradation. The results present that the size of ZrO2 has a significant impact on PBR discharge characteristics due to its influence on physical parameters. Moreover, bigger ZrO2 beads packing shows a better performance in SF6 degradation because of longer gas residence time. In addition, the key operating parameters including flowrate, SF6 concentration, oxygen concentration, and water vapor concentration were optimized by response surface methodology (RSM) with Box-Behnken design (BBD). The proposed optimization model shows satisfactory correlation between the predicted and actual results. For energy yield (EY), the mutual effect of flowrate, SF6 concentration and water vapor concentration was significant. For SO2F2 selectivity, the mutual effect of SF6 concentration and water vapor concentration was significant. The optimum SF6 abatement was predicted from RSM as 14.64g/kWh and 14.42% for EY and SO2F2 selectivity at flowrate of 200mL/min, SF6 concentration of 3%, oxygen concentration of 0.83% and water vapor concentration of 1.89%.