Contribution of electron density to plasma decomposition rate of methane

Abstract

Hydrogen extraction from methane will be a common and useful technique in hydrogen production systems and fuel cycle systems of deuterium-tritium fusion reactors. Since tritium is a precious fuel, it needs to be extracted from impurity gases such as tritiated methane contained in the exhaust gas from the plasma vessel of a fusion reactor. An experimental work was conducted in this study to investigate the electron collision of methane decomposition reaction in helium plasma. A special attention was placed on the electron density distribution in a plasma chamber, and the dependence of the decomposition rate on the methane/helium ratio. The experimental results showed that methane decomposition rate and electron density tended to increase linearly with increasing RF power. This suggests that a strong dependence of electron collision on methane decomposition. Eventually, the dependence of methane decomposition rate on electron density, total pressure, and inlet methane concentration in a gas flow-type helium plasma reactor was successfully formulated. This study provides new sight for demonstrating the contribution of electron density in RF plasma assisted methane decomposition, and the summarized equation offers potential for reactor design on promising energy utilization.