Experimental study on high frequency capacitively coupled plasma–catalysishybrid system for methane complete oxidation

Özet

Methane (CH4) is the second most important anthropogenic greenhouse gas in the atmosphere after CO2. In thiswork, CH4oxidation was investigated in a high frequency capacitively coupled discharge quartz tube reactorwhere both catalyst and high frequency capacitively coupled plasma (CCP) were hybridized into one in-plasmacatalysis system. The calcium titanium catalyst were used as oxidation catalyst. Experiments have been per-formed to examine the characteristics of this high frequency capacitively coupled dischargefirstly. It was foundthat the input power and using catalyst or not were the key parameters affecting the plasma characteristics suchas plasma length, temperature, and energy transfer efficiency. Then the conversion efficiency of CH4and pro-ducts of reaction were analyzed in the absence of catalyst. The result indicates that the CH4conversion efficiencywill increase with the increase of input power, thefinal products of CH4oxidation were CO, CO2and H2O, NOand NO2were by-products from the oxidation of CH4. The synergistic effect of CCP and catalyst for oxidationwas studied also and compared to the cases without catalyst in the reactor. When the catalyst was present, theCH4conversion efficiency was improved, the CO2selectivity was increased in the reaction product, the by-product concentration of NO and NO2was decreased.