| Plasma chemical reaction is an important technology in modern chemical field. Radio frequency plasma is a kind of non-equilibrium cold plasma. In this paper reactions of methane conversion in the presence of oxygen by this method and the new ways of converting methane into C2 hydrocarbons have been studied. The method of discharge at low pressure has been chosen to design five different kinds of plasma reactors according to the basic principles of radio frequency plasma reactions. The effects of five different kinds of reactors have been compared by the experiments of ammonia synthesis and the result that the TII type reactor is more favorable to the reaction has been attained. Based on the characteristics of conversion of methane in the presence of oxygen, the cannula type reactor has been used as the reactor of methane conversion in the presence of oxygen. The main goal products, H2, C2H4, C2H6, C2H2 and a little of CO2, have been obtained in the systemic experiments of methane conversion under radio frequency plasma in the presence of oxygen. The results showed that the factors of discharge voltage, discharge area, ratio of O2/CH4 and total gas flux have a remarkable influence upon the methane conversion, C2 hydrocarbons yield and selectivity. Then the better conditions of methane conversion have been obtained: 1150V of discharge voltage, 7.065cm2 of discharge area, 0.17 ratio of O2/CH4, 220ml/min of total gas flux. Finally, 80.4% methane conversion, 14.3% C2 hydrocarbons yield and 18.7% C2 hydrocarbons selectivity have been attained. According to the equation of reaction rate constant K of dissociation reactions between energetic electrons and molecules and the experimental results, the macroscopic kinetics model of CH4+O2 radio frequency plasma reactions has been studied. And the kinetic parameters have been calculated by Origin7.0 software. The macroscopic kinetics equation has been obtained: -rCH4=8. 6331exp(-137.91/W)·CCH40.31462·CO20.060583By the analysis of reaction mechanism of the methane conversion in the presence of oxygen according to the plasma reaction principles and the components of products, the conclusion was that the goals were produced in the radical chain reactions arose from the collisions between energetic electrons and O2 or CH4. Several possible radical reactions have been chosen as the main radical reactions of producing goals.
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