Study On The New Technology Of Conversion Of Natural Gas Through Low Temperature Plasma

Both CO2 and CH4 are major greenhouse gases and CH4 is also a major constituent of natural gas. With the continuous decrease of petroleum resources, more and more attention has been focused on the exploitation of natural gas that is abundant worldwide. Conversion of CH4 and CO2 is concerned not only to energy utilization and resource disposition in the future, but also to protection of the environment. In this paper both reactions of CH4 coupling to produce C2 hydrocarbons and conversion of CH4 and CO2 to syngas through glow discharge of nonequilibrium plasma reaction were studied. A novel reactor with a rotating multi-tip electrode was used and a cooler was added to the outside of the reactor to reduce the temperature. The effect of parameters of the electric field and reaction conditions on both reactions and the characteristics of energy consumption under different technology conditions were investigated. For CH4 coupling reaction, both the conversion of CH4 and the yield of C2 hydrocarbon increased, while the coke formation was reduced to some degree and the energy efficiency was improved compared with those with other kinds of discharge and electrodes. The optimal conversion of CH4 and yield of C2 hydrocarbons were over 70% and the optimal selectivity of C2 hydrocarbons was over 90% with energy efficiency over 20%.For the reaction of CH4 and CO2 to syngas the result of glow discharge plasma reaction was compared with that of corona discharge plasma reaction. It was found that the rules of both of reactions were a little different and the conversion of CH4 and CO2 in glow discharge plasma reaction was lower comparatively. In glow discharge plasma reaction the energy efficiency was 14.1% and the optimal conversion of CH4 and CO2 was 70% and 63% respectively at the energy density of 1075 kJ.mol-1 and n(CH4)/n(CO2)=1:1, while in corona plasma reaction the energy efficiency was 12.83% and the optimal conversion of CH4 and CO2 was 93.71% and 94.02% respectively at the energy density of 1602 kJ.mol-1 and n(CH4)/n(CO2)=1:1.It was found that the coke formed in glow discharge plasma reaction could be eliminated with H2 discharge or argon discharge and the latter was better. The methods and the mechanism of eliminating the coke were provided based on the study of coke formation during reaction.