Research on Environmental Protection Treatment for Ex-Service SF6 Adsorbent

SF6 adsorbents absorb many toxic SF6 decomposition products, such as SOF2, SO2F2, and H2S. Ex-service SF6 adsorbents that did not undergo environmentally friendly processing will seriously harm the environment. In this work, thermogravimetric analysis and Fourier transform infrared spectroscopy were used to investigate the adsorbates of ex-service SF6 adsorbents. Adsorbent recycling based on the thermal method was also studied. The vacuum thermal method increased the recycling efficiency of ex-service SF6 adsorbents to 85%-90%. In addition, the adsorbents recovered through thermal method could be reused in SF6-gas-insulated equipment. Considering their influence on equipment operation and maintenance, a harmless treatment technology for ex-service SF6 adsorbents with Ca(OH)2 was proposed. The adsorption and desorption behaviors of SF6 adsorbents were predicted via destiny functional theory. The best treatment effect could be obtained when the Ca(OH)2 amount was equal to 20% of the treatment weight of the adsorbents, and the treatment temperature was maintained at 90 °C. The economic feasibility of the harmless treatment for ex-service SF6 adsorbents with Ca(OH)2 was higher than that of the thermal method.