Theoretical evaluation of the interaction between C5-PFK molecule and Cu (1 1 1)

Study on the Reaction Mechanism of Ethylene Propylene Diene Monomer Sealing Material and C5F10O-CO2 Gas Mixture

The eco-friendly insulating medium C₅F₁₀O gas has attracted the attention of many researchers due to its superior environmental protection and insulation properties. However, there are few studies on the compatibility of C₅F₁₀O gas with sealing materials for the gas-insulated equipment (GIE), which will bury hidden dangers for its engineering application. In this study, the compatibility of C₅F₁₀O gas with an ethylene propylene diene monomer (EPDM) sealing material which is most used in equipment was tested, and its reaction mechanism was simulated. The study found that the O element on the carbonyl group of C₅F₁₀O gas has high chemical reactivity and will interact with EPDM rubber. During the interaction process, EPDM rubber will also react with the C₃F₆ gas generated by the decomposition of C₅F₁₀O gas, and at the same time, it will also decompose C₅F₁₀O gas to produce more C₃F₆O and C₃HF₇. The surface of EPDM rubber will produce oily substances and a large number of crystal particles, which will cause its mechanical properties to deteriorate and shorten its service life. Therefore, it is necessary to carry out anti-corrosion treatment on the surface of EPDM rubber or replace the sealing material with better compatibility when designing and manufacturing GIE.

Alternative Environmentally Friendly Insulating Gases for SF6

Sulfur hexafluoride (SF6) shows excellent insulation performance as an insulating gas. It is suitable for various climate conditions due to its low boiling point (−64 °C). Therefore, it has been widely used in power grid equipment. However, its global warming potential (GWP) is 23,500 times higher than that of CO2. Thus, it is imperative to find an environmentally friendly insulating gas with excellent insulation performance, lower GWP, and which is harmless to equipment and workers to replace SF6. In this review, four possible alternatives, including perfluorocarbons, trifluoroiodomethane, perfluorinated ketones, and fluoronitrile are reviewed in terms of basic physicochemical properties, insulation properties, decomposition properties, and compatibility with metals. The influences of trace H2O or O2 on their insulation performances are also discussed. The insulation strengths of these insulating gases were comparable to or higher than that of SF6. The GWPs of these insulating gases were lower than that of SF6. Due to their relatively high boiling point, they should be used as a mixture with buffering gases with low boiling points. Based on these four characteristics, perfluorinated ketones (C5F10O and C6F12O) and fluoronitrile (C4F7N) could partially substitute SF6 in some electrical equipment. Finally, some future needs and perspectives of environmentally friendly insulating gases are addressed for further studies.