Application of a Microwave Helium Plasma Torch Operating at Atmospheric Pressure to Destroy Trichloroethylene

Abstract

We examined the influence of the gas flow-rate, microwave power and trichloroethylene concentration on the destruction of trichloroethylene with a system based on a microwave helium plasma operating at atmospheric pressure. Based on the experimental results obtained, the proposed system allows input concentrations of C 2 HCl 3 in the ppmv range to be reduced to output concentrations in the ppbv range (i.e. virtually quantitative destruction) by using a microwave plasma power below 1000 W. High helium flow-rates and C 2 HCl 3 concentrations allow energy efficiency values above 600 g/kW h to be obtained. Analyses of the output gases by gas chromatography and species present in the plasma by optical emission spectroscopy confirmed the negligible presence of halogen compounds resulting from the destruction of C 2 HCl 3 , and that of CCl 4 and C 2 Cl 4 as the sole chlorine species exceeding levels of 30 ppbv. Gaseous by-products consisted mainly of CO 2 , NO and N 2 O in addition to Cl 2 traces.

Application of microwave air plasma in the destruction of trichloroethylene and carbon tetrachloride at atmospheric pressure

“…With an argon or helium plasma at atmospheric pressure, this system was proven to be effective at destroying carbon tetrachloride and trichloroethylene [21][22][23], and destruction rates greater than 99% were achieved. Using air as the main gas decreases the cost of the process because air can be obtained from the atmosphere, while argon and helium must be purchased.…”

Studies on destruction of silicon tetrachloride using microwave plasma jet

“…At a microwave power settings from 400 to 800 W, the SiCl 4 output concentration decreased and the contaminant destruction efficiency increased with increasing power. A concentration range exists where the destruction efficiency is maximal that changes with the microwave power [17]. The curves are similar in shape for any microwave power, and SiCl 4 concentration above 1.0% leads to an increased output concentrations of SiCl 4 caused by a decreased residence time in the plasma and result in a poorer destruction efficiency.…”

Study of Gas Heating by a Microwave Plasma Torch

“…The electron density is deduced from Stark broadening measurements of the H β line [19,20], recorded using a [8][9][10][11][12][13][14][15]. The electron temperature could not be measured due to the experimental lack of precision.…”

“…These studies have shown that the TIA could be efficient in applications such as analytical chemistry [13] (in relation also with its ability to create chemically active species), surface treatment [14] and gas treatment [15].…”