微波等离子体下甲烷脱氢偶联制C_2烃

DEHYDROGENATION COUPLING OF METHANE TO C_2 HYDROCARBONS UNDER THE CONDITION OF MICROWAVE PLASMA

在微波等离子体下 ,研究了甲烷以及甲烷和水脱氢偶联制C2 烃的反应。对影响甲烷转化率和产物选择性的几个因素 (微波输入功率、反应物的比例 )进行了研究。在甲烷体系中 ,随着微波输入功率的增加和体系压力的降低 ,甲烷的转化率和乙炔的选择性都增大 ;乙烷的选择性则降低 ;乙烯的选择性随体系压力的增大而增大 ,随功率的增大出现极大值。在甲烷和水体系中 ,随着微波输入功率的增加 ,甲烷的转化率和乙炔的选择性随着增大 ;乙烷的选择性随之降低 ;乙烯的选择性出现极大值 ;当反应物比 (H2 O/CH4)增大时 ,甲烷的转化率和乙烷的选择性随之增大 ,而乙炔和乙烯的选择性则降低。等离子体中的电子能量和密度采用静电悬浮双探针法进行了诊断 ,电子密度和能量要受微波输入功率和体系压力的影响 ,并且在反应中电子能量决定化学反应是否进行 ,电子密度决定产物的组成。根据自由基反应理论解释了甲烷的转化率和产物的选择性在CH4和H2 O +CH4体系的等离子体化学反应中随影响因素的变化规律。

The reaction of dehydrogenation coupling of methane and methane with water under the condition of microwave plasma was studied. The several factors of affecting the conversion of methane and the selectivity of products, such as microwave input power and ratio of reactants (H 2O/CH 4) were discussed. In the reaction system of methane, the conversion of methane and selectivity of acetylene increase along with increasing of the microwave input power and decreasing of system pressure, but the selectivity of ethane decreases at the same time. However, the selectivity of ethylene increases along with increasing of system pressure and appears a maximum value as increasing of the microwave input power. In the reaction system of methane with water, the conversion of methane and selectivity of acetylene increase, the selectivity of ethane decreases at the same time, and the selectivity of ethylene reaches the maximum value in pace with increasing of the microwave input power. On the other hand, the conversion of methane and selectivity of ethane increase, but the selectivity of ethylene and acetylene decreases at the same time with increasing of ratio of reactants (H 2O/CH 4). The electron energy and density (Ne) in the plasma was affected by microwave input power and system pressure and diagnosed by the floating double electrostatic probes. During the reaction, the processing of chemical reaction depends on how much of the electron energy, and the composition of products are decided by the density (Ne). According to radical reaction theory, the varying law of methane conversion and selectivity of products with affecting factors was explained in the reaction system of methane and methane with water under the condition of microwave plasma.