Theoretical study by density functional theory calculations of decomposition processes and primary products of C <sub>5</sub> F <sub>10</sub> O with moisture content
Lipeng Zhong, Yongchao Deng, Jie Liu, Feng Wang, She Chen, Qiuqin Sun, XiaoLi Duan, Haibo Huang
Abstract
Abstract C 5 F 10 O has been widely studied as a great potential alternative gas to SF 6 , a most potent industrial greenhouse gas that is predominantly used as an insulating medium in electrical equipment, due to its excellent insulation properties and environmental characteristics. Several experimental and theoretical attempts have been made and have obtained valuable results in the last five years. However, few researchers have thoroughly investigated the decomposition mechanism and the main decomposition pathways of the C 5 F 10 O/H 2 O system, which are important for evaluating the insulating and environmental performance and providing guidance for engineering application. Herein, the decomposition characteristics and mechanism of C 5 F 10 O in the presence of moisture content was studied by density functional theory calculations. The main types of decomposition products with relatively high content have been summarized based on the evaluation of cleavage reactions and the influence of moisture. The electrical, environmental and safety performances of the primary products were analyzed. CF 3 CFCF 3 , CF 3 CO, CF 3 , OH and H radicals are the most primary particles formed by dissociation of C 5 F 10 O and H 2 O. These particles may further convert into more than 20 kinds of relatively stable products, among which C 4 F 10 , C 3 F 8 , C 6 F 14 , C 3 HF 7 , C 2 F 6 and CO are primary ones. In addition, COF 2 , CO 2 , CO and C 3 F 6 can be used as components for estimating the degree of failures. The existence of H 2 O has a negative impact on the insulation and environmental performance. In particular, trace water has a direct contribution to the production of highly toxic COF 2 , CO and HF. Thus, it is necessary to strictly control the moisture and develop application standards before any industrial application of C 5 F 10 O in electrical equipment.