Plasma-assisted abatement of SF6 in a dielectric barrier discharge reactor: investigation of the effect of packing materials

The greenhouse gas hexafluoride (SF6) and its degradation is a research hotspot in the environmental field. In a double-layer dielectric barrier discharge reactor, the degradation process of SF6 was studied when packed in glass beads or gamma-Al2O3 pellets as well as with no packing system. The results show that the packing materials changed the physical characteristics of the discharge, increasing the equivalent capacitance and discharge power and leading to the generation of more active particles and high-energy electrons. Additionally, the two packing materials effectively improved the degradation removal efficiency (DRE) and energy yield (EY) of SF6. In the gamma-Al2O3 system, 2% SF6 gas obtained a maximum DRE of 85.97% with a 110 W input power and the EY reached 9.17 g kWh(-1), far exceeding the case without packing. Moreover, the glass bead packing had no obvious effect on the degradation products, while the packing of gamma-Al2O3 particles promoted SO2 production and reduced the formation of SOF2, SO2F2 and SOF4. Meanwhile, in the gamma-Al2O3 system, the yield of SO2 increased with increasing input power and some undesirable products such as SO2F2 were reduced. These results show that the addition of suitable packing materials such as gamma-Al2O3 pellets can effectively promote the harmless degradation of SF6.