Decomposition characteristics of C3F7CN under the presence of H2O and O2 based on molecular dynamics

Abstract

SF6 (Sulfur hexafluoride) was widely used in gas insulated electrical equipment. However, it is a strong greenhouse gas with a GWP (global warming potential) of 23900. In recent years, C3F7CN (heptafluoro-iso-butyronitrile) was proved to be a potential substitute gas with excellent insulation performance and low greenhouse effect. In this paper, the decomposition of C3F7CN under the presence of H2O and O2 was studied based on the ReaxFF-MD (reactive force field molecular dynamics). It was found that H2O would promote the decomposition of C3F7CN. Compared with the 130 C3F7CN molecule remained in the pure C3F7CN system, the number of C3F7CN in the adding 50 H2O system is 100 at 1000ps. HF, COF2 were produced in the adding H2O systems. The number of HF increased with the number of H2O added and there were 34 HF formed in the adding 50 H2O system in the end. 1 COF2 was generated in the adding 30, 50 H2O systems. O2 had no significant effect on the decomposition of C3F7CN, although a small amount of COF2 were formed. The simultaneous presence of H2O and O2 promoted the decomposition of C3F7CN, and it was close to the promotion of pure H2O. The number of HF and COF2 in the adding H2O/ O2 systems were close with that in the adding H2O systems. Utilizing molecular dynamics to study the decomposition of C3F7CN under the presence of H2O and O2 on the provides theoretical support for the study of C3F7CN gas characteristics.