Chemical species produced in arc-quenching gas CO2/O2 mixed with C3H2F4, C4-FN or C5-FK: prevention of condensed-phase carbon formation and its formulation

Abstract

Regarding CO2/O2-based mixture as an arc quenching gas in high-voltage circuit breakers, the predominant component species present in high numbers at temperatures of 300–20 000 K are determined in consideration of addition of CF3CFCH2 (hereinafter written as C3H2F4) gas to the CO2/O2-based mixture. In the determination, not only are 87 gaseous species but also condensed-phase carbon (hereinafter written as C(c)) taken into account as component species. The evaluation results reveal that CO2, O2, CF4 and HF in gaseous phase behave as the predominant component species at 300–1000 K for lower content additive-gas, whereas the species C(c) is also generated as the predominant component at the same temperature for higher content additive-gas.Subsequently, reactions of chemical elements C, O, F and H to form the above-described chemical species are successfully expressed using CO2, O2 and C3H2F4 contents as stoichiometric coefficients. Expressing the reactions furthermore enables us to formulate the prevent condition of the C(c) generation as a function of O2 content and C3H2F4 content . Similar formulations are successfully performed for CO2/O2/C4-FN and CO2/O2/C5-FK mixtures.