Effects of ambient gas on cold atmospheric plasma discharge in the decomposition of trifluoromethane

Abstract

The effect of dilution gases (He, Ar and N₂) on plasma discharge in the decomposition of trifluoromethane (CHF₃) was investigated in dielectric barrier discharge at atmospheric pressure. A comparison among these dilution gases was performed in terms of active power, apparent power, power factor, impedance, and power efficiency for the decomposition of CHF₃. He dilution showed the most homogeneous and stable discharge among the dilution gases. However, Ar dilution ignited the generation of streamers in the plasma discharge, resulting in a relatively superior power efficiency in CHF₃ decomposition. In addition, due to the plasma reactions between O₂ and N₂, N₂ as a dilution gas had a disadvantaging tendency to form nitric oxide compounds (harmful compounds). Complete decomposition of CHF₃ could be performed under the following conditions; Ar dilution, active power ≥ 40 W, a CHF₃ fraction of 0.2% and a total flow rate of 1000 ml min⁻¹.