Energy Density Dependence of Hydrogen Combustion Efficiency in Atmospheric Pressure Microwave Plasma

Recovery of tritium in nuclear fusion plants is a key issue for safety. So far, the oxidation procedure using atmospheric pressure plasma is expected to the recovery method. In this study, to clarify the mechanism of hydrogen oxidation by plasma chemistry, we investigated the dependence of hydrogen combustion efficiency on gas flow rate and input power in the atmospheric pressure microwave plasma. It is found that the combustion efficiency depended on energy density of absorbed microwave power. Hence, the energy density is considered as a key parameter for combustion processes.

Also neutral gas temperatures in and outside of the plasma were measured by an optical emission spectroscopy method and thermocouple. The result shows that the neutral gas temperature in the plasma is much higher than the outside temperature of plasma. The high neutral gas temperature would affect to the combustion reaction.