Decomposition mechanism of HFC-134a, and CF 4 in water plasmas at atmospheric pressure has been investigated. The decomposition efficiency of 99.9% can be obtained up to 3.17 mol kWh -1 of the ratio of hydrofluorocarbon (HFC) feed rate to the arc power and 1.89 mol kWh -1 of the ratio of perfluorocarbon (PFC) feed rate to the arc power. The species such as H 2 , CO, CO 2 , CH 4 , and CF 4 were detected from the effluent gas of both PFC and HFC decomposition. However, CH 2 F 2 and CHF 3 were observed only in the case of HFC decomposition. The HFC and PFC decomposition generate CH 2 F, CHF x (x:1-2) , and CF y (y:1-3) radicals, then those radicals were subsequently oxidized by oxygen, leading to CO and CO 2 generation in the excess oxygen condition. However, when there is insufficient oxygen available, those radicals were easily recombined with fluorine to form by-product such as CH 2 F 2 , CHF 3 , and CF 4 .
Decomposition system of liquid waste by DC water plasmas generated at atmospheric pressure was developed. The developed water plasma torch is a DC thermal plasma generator of coaxial design with a cathode of hafnium embedded into the copper rod and a nozzle-type copper anode. The plasma torch can generate 1 00%-steam plasma without a commercially available steam generator. The water plasma system is a portable light-weight system that does not require any gas supply. The plasma system has high energy-efficiency since cooling water is not needed. Methanol or ethanol used as model substances of liquid waste was mixed with water for plasma supporting gas. Rapid and complete decomposition for these alcohols produce H 2 , CO, and C0 2 in the decomposed gas. The decomposition rate as well as the decomposition mechanism was determined by gas chromatography and mass spectrometry. The water plasma system can be used for industrial application of liquid waste decomposition.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.