SF6 abatement in a packed bed plasma reactor: study towards the effect of O2 concentration

Abstract

SF₆ is a greenhouse gas with extremely high global warming potential value (GWP). In this paper, oxygen and a packed bed plasma reactor (PBR) were applied to remove it. The synergistic effect between oxygen and PBRs was evaluated by the destruction and removal efficiency (DRE) and energy yield (EY) at different oxygen concentrations. The results show that excessive oxygen weakened the micro-discharge in a PBR to suppress SF₆ degradation while the addition of a proper amount of oxygen (1–4%) can improve the DRE and EY. 2% O₂ in the system had the best promoting effect on the destruction of 6–10% SF₆, which made the maximum energy yield (EY) increase by 50.99% to 37.99 g kW⁻¹ h⁻¹ (SF₆ concentration was 10%, flow rate was 150 mL min⁻¹). Moreover, in the flow rate range of 100 mL min⁻¹ to 250 mL min⁻¹, the DRE decreased and the EY increased with the flow rate. In addition, the selectivity of different products were affected by the oxygen concentration. For 6% SF₆, SO₂F₂ selectivity was always the highest while SO₂ was always the lowest; when the oxygen concentration did not exceed 2%, SOF₂ selectivity was higher than SOF₄, otherwise, SOF₄ selectivity was higher than SOF₂. This paper provided experimental support for better understanding of the effect of additional gas concentration on SF₆ decomposition in a PBR.