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

SF
6
(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, C
3
F
7
CN (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 C
3
F
7
CN under the presence of H
2
O and O
2
was studied based on the ReaxFF-MD (reactive force field molecular dynamics). It was found that H
2
O would promote the decomposition of C
3
F
7
CN. Compared with the 130 C
3
F
7
CN molecule remained in the pure C
3
F
7
CN system, the number of C
3
F
7
CN in the adding 50 H
2
O system is 100 at 1000ps. HF, COF
2
were produced in the adding H
2
O systems. The number of HF increased with the number of H
2
O added and there were 34 HF formed in the adding 50 H
2
O system in the end. 1 COF
2
was generated in the adding 30, 50 H
2
O systems. O
2
had no significant effect on the decomposition of C
3
F
7
CN, although a small amount of COF
2
were formed. The simultaneous presence of H
2
O and O
2
promoted the decomposition of C
3
F
7
CN, and it was close to the promotion of pure H
2
O. The number of HF and COF
2
in the adding H
2
O/ O
2
systems were close with that in the adding H
2
O systems. Utilizing molecular dynamics to study the decomposition of C
3
F
7
CN under the presence of H
2
O and O
2
on the provides theoretical support for the study of C
3
F
7
CN gas characteristics.