Despite its industrial value, sulfur hexafluoride (SF6 ) has a high global warming potential of about 24,000, and proper processing is therefore required. In this study, we examined SF6 decomposition treatment by long DC arc, a new thermal plasma generation method, with addition of steam, H2, or O2. The long DC arc was generated between electrodes with a gap of 300 mm at about 5 kW of arc power. Destruction and removal efficiency of 99% or more was obtained with steam and H2 addition, whereas a maximum of 89% was obtained with O2 addition. As byproducts, H2S was generated with excess H2 addition, and the greenhouse gas SO2F2 was generated with insufficient H2O or O2 addi-tion. In order to suppress these harmful byproducts, it is desirable to have a strong oxidizing atmosphere and to recover fluorine in the form of HF. Processing with addition of steam at an H/F molar ratio of unity or above was found to be ideal for safe and complete decomposition of SF6.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)