Experimental study of abatement of SF6 gas using an atmospheric-pressure oxygen microwave plasma torch

An atmospheric-pressure microwave oxygen plasma torch (APMPT) is used for abating SF6 gas. The gas composition is analyzed with a Fourier transformation infrared spectrometer, and the abating effect is evaluated in terms of the destruction removal efficiency (DRE). The variation of SF6 DRE is investigated with respect to the microwave power, the gas flow rate, SF6 concentration, and the material and length of discharge tube. It is found that the existence of free-discharge regions in the vicinity of the inner wall of the discharge tube, influenced by the flow rate and microwave power, plays an important role in maintaining a stable discharge and determining the DRE value. The energy efficiency can be improved significantly by using quartz discharge tubes of a suitable length. Meanwhile, the explanations about the variation of DRE and energy efficiency for decomposing SF6 by APMPT are provided reasonably.