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运用微波等离子体技术研究了甲烷和氮气的化学反应。考察了反应条件对产物选择性和甲烷转化率的影响。甲烷转化率随着微波输入功率的增大和反应物配比 (n(CH4) /n(N2 ) )的减小而增大 ;在最佳条件下 ,甲烷转化率达96 2 %。HCN选择性随着n(CH4) /n(N2 )比的增大而降低 ;在n(CH4) /n(N2 ) <0 995时 ,HCN为主产物 ,且HCN的选择性随微波输入功率的增大而减小 ,在最佳条件下 ,HCN选择性达 91 4% ;在n(CH4) /n(N2 ) >0 995时 ,C2 H2 为主产物 ,然而HCN选择性随着微波输入功率的增大而增加。C2 H2 选择性随着微波输入功率的增大而增加 ,随着n(CH4) /n(N2 )的增大出现极大值 ;在最佳条件下 ,C2 H2 选择性达 72 77%。C2 H2 和C2 H6 的选择性随着微波输入功率的减小和n(CH4) /n(N2 )的增大而增加。对甲烷、氮气等离子体的电子温度和电子密度进行了诊断 ,并运用自由基反应理论解释了反应条件对甲烷转化率和产物选择性的影响。
The chemical reaction of methane and nitrogen was studied by microwave plasma technology. The effects of reaction conditions on product selectivity and methane conversion were investigated. The conversion of methane increased with the increase of microwave input power and the decrease of the ratio of reactants (n (CH4) / n (N2)). Under the optimum conditions, methane conversion reached 96.2%. HCN selectivity decreases with the increase of n (CH4) / n (N2) ratio; HCN is the main product at n (CH4) / n (N2) <0 995, and the selectivity of HCN varies with microwave input power HCN selectivity reached 91.4% under the optimal conditions; C2H2 was the main product at n (CH4) / n (N2)> 0 995. However, the selectivity of HCN with microwave input Increased power increases. C2 H2 selectivity increases with the increase of microwave input power, with the maximum value of n (CH4) / n (N2) increasing; under the optimal conditions, C2 H2 selectivity reaches 72 77%. The selectivity of C2 H2 and C2 H6 increases with the decrease of microwave input power and the increase of n (CH4) / n (N2). The electronic temperature and electron density of methane and nitrogen plasma were diagnosed, and the influence of reaction conditions on methane conversion and product selectivity was explained by the theory of free radical reaction.