Thermal decomposition characteristics of C6F12O/CO2 gas mixtures under trace water conditions

Abstract

In recent years, C₆F₁₂O gas mixtures has shown extensive prospects for application in medium and low-voltage gas-insulated equipment due to its superior electrical performance and environmental friendliness. The presence of trace water may promote overheating decomposition of gas mixtures_. Therefore, studying the thermal decomposition characteristics of C₆F₁₂O in a trace water condition is of significant importance for the industrial application, operation, and maintenance of gas equipment. In this paper, the thermal decomposition characteristics of C₆F₁₂O/CO₂ gas mixtures under trace water conditions are investigated both experimentally and theoretically. The analysis of decomposition products is conducted using gas chromatography-mass spectrometry (GC–MS) on a constructed experimental platform for C₆F₁₂O/CO₂ gas mixtures overheating. Based on ReaxFF molecular dynamics (ReaxFF-MD), the decomposition characteristics of the gas mixtures over time and the concentration of trace water are observed. The main decomposition reaction paths of C₆F₁₂O/CO₂ gas mixtures under trace water conditions are analyzed at a microscopic level. Experiment results indicate that the main thermal decomposition products include CF₄, C₂F₆, C₃F₆, C₃F₈, CF₂O, C₃F₇H, C₄F₁₀, C₆F₁₄, C₅F₁₂, and CF₃H. Additionally, trace water facilitates the thermal decomposition of the C₆F₁₂O/CO₂ gas mixtures. Theoretical results indicate that multi-step decomposition occurs in the C₆F₁₂O component of the gas mixtures, with main generated intermediates including CO, F, CF₃, C₂F₅, C₃F₇, CFO₂, CF₂, C₂, CF, C₄F₇O, CF₃O, CFO, O, C₃F₅O, CF₂O, C, C₂O, H, and OH. The findings of this study provide a foundation for further exploration of trace water content values in C₆F₁₂O gas mixtures at a microscopic level in subsequent research.