CF4 decomposition by thermal plasma processing

Abstract

Decomposition of CF4 was investigated by thermal plasma method. Thermal plasma processes applied to environmental problems have the features of high temperature, high activity and rapid decomposition rate, so it can perfectly decompose non-decomposed materials like CF4 to a high degree. Before the experiment, thermodynamic equilibrium calculations were performed from 300 K to 5,000 K at atmospheric pressure. Based on the thermodynamic equilibrium calculations, the trends in decomposition and recombination of CF4 were studied. Decomposition was carried out by injecting mixtures of CF4 bubbled by Ar, with some addition gases, such as H2 and O2, at atmospheric pressure. Experiments were performed to determine the effects of additive gas identity, additive gas dilution, input power, etc. on the decomposition of CF4. Plasma input power has a slight effect on CF4 decomposition, and the injection of reacting gas through a torch increased CF4 decomposition. Supply of H2 and O2 as addition gases increased the CF4 decomposition to 99% for experimental conditions tested.