Chemical species produced in arc-quenching gas CO <sub>2</sub> /O <sub>2</sub> mixed with C <sub>3</sub> H <sub>2</sub> F <sub>4</sub> , C4-FN or C5-FK: prevention of condensed-phase carbon formation and its formulation
Yasunobu Yokomizu, Motohiro Sato, Naoto Kodama, Takahiro Edo, Kentaro Kokura
Abstract
Abstract Regarding CO 2 /O 2 -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 CF 3 CFCH 2 (hereinafter written as C 3 H 2 F 4 ) gas to the CO 2 /O 2 -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 CO 2 , O 2 , CF 4 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 CO 2 , O 2 and C 3 H 2 F 4 contents as stoichiometric coefficients. Expressing the reactions furthermore enables us to formulate the prevent condition of the C(c) generation as a function of O 2 content and C 3 H 2 F 4 content . Similar formulations are successfully performed for CO 2 /O 2 /C4-FN and CO 2 /O 2 /C5-FK mixtures.