Enhanced Degradation of Benzene in Surface/Packed-Bed Hybrid Discharge System: Optimization of the Reactor Structure and Electrical Parameters

Abstract

The effects of reactor structure parameters (wire diameter of the coil electrode, screw pitch of the coil electrode, inner diameter of the quartz tube, and packing material) and electrical parameters (power supply mode, pulse repetitive frequency, and pulse-forming capacitance) on discharge characteristics and benzene degradation have been systematically investigated in a surface/packed-bed hybrid discharge (SPBHD) reactor. The experimental results indicate that the coil electrode with a wire diameter of 1 mm and a screw pitch of 7.5 mm appears to be more advantageous with respect to both degradation efficiency and energy yield (EY). The quartz tube with larger diameter is more beneficial to benzene degradation but not for $EY$ . The reactor packed with BaTiO3 hollow cylinders can decompose benzene more effectively than that packed with the other materials, but goes against $EY$ . The reactor driven by bipolar pulsed power supply favors the generation of energetic electrons and active species than ac power supply, and thus accelerates benzene degradation. Increasing the pulse voltage and pulse repetitive frequency are found to be favorable for improving energy injected into the SPBHD reactor as well as the benzene degradation, while more energy is consumed. In this system, ${f}=50$ Hz and ${C}_{{p}}=2$ nF are the optimal pulse repetitive frequency and pulse-forming capacitance for the bipolar pulsed power, respectively, after considering the benzene degradation and $EY$ comprehensively.