The oxidative coupling of methane over La203/CaO type-catalyst in a fixed-bed reactor is studied under a wide range of operating conditions （973〈T〈 1103 K, 55〈 Ptotal 〈220 kPa, and 3.7〈 mcat/VTp 〈50 kg.s/m^3）....The oxidative coupling of methane over La203/CaO type-catalyst in a fixed-bed reactor is studied under a wide range of operating conditions （973〈T〈 1103 K, 55〈 Ptotal 〈220 kPa, and 3.7〈 mcat/VTp 〈50 kg.s/m^3）. A ten-step kinetic model incorporating all main products was used to predict the behavior of the system. Methane conversions and C2 selectivities were calculated by varying methane to oxygen ratios in the feed under different operating conditions which were also compared with the rule of 100. The results show that deviation from this rule depends on the operating conditions. Within the range studied, an increase in pressure, temperature and contact time results in smaller deviation from the rule. This rule is best approximated when the catalyst operates near its optimal performance. For negative deviations, common to the most catalysts, it is found that the optimal performance should occur at methane conversion levels lower than 50%. A plot of selectivity versus conversion for high-yield reported performance data of a large variety of catalysts shows that data points concentrated roughly in 20%-50% methane conversion region, confirming the generality and prediction of modeling.展开更多
提出了一个稠合型簇合物的稠合规则,讨论了唐氏拓扑结构规则和Mingos稠合规则的推广,扩大了两个稠合规则的应用范围。研究了在稠合型簇合物中Teo的C2模型与Mingos稠合规则、推广的唐氏拓扑结构规则和本文提出的稠合规则之间的关系。同时...提出了一个稠合型簇合物的稠合规则,讨论了唐氏拓扑结构规则和Mingos稠合规则的推广,扩大了两个稠合规则的应用范围。研究了在稠合型簇合物中Teo的C2模型与Mingos稠合规则、推广的唐氏拓扑结构规则和本文提出的稠合规则之间的关系。同时,利用提出的稠合型簇合物的稠合规则导出了超级簇合物"clusters of clusters"中原子和电子之间存在的魔数关系。展开更多
文摘The oxidative coupling of methane over La203/CaO type-catalyst in a fixed-bed reactor is studied under a wide range of operating conditions （973〈T〈 1103 K, 55〈 Ptotal 〈220 kPa, and 3.7〈 mcat/VTp 〈50 kg.s/m^3）. A ten-step kinetic model incorporating all main products was used to predict the behavior of the system. Methane conversions and C2 selectivities were calculated by varying methane to oxygen ratios in the feed under different operating conditions which were also compared with the rule of 100. The results show that deviation from this rule depends on the operating conditions. Within the range studied, an increase in pressure, temperature and contact time results in smaller deviation from the rule. This rule is best approximated when the catalyst operates near its optimal performance. For negative deviations, common to the most catalysts, it is found that the optimal performance should occur at methane conversion levels lower than 50%. A plot of selectivity versus conversion for high-yield reported performance data of a large variety of catalysts shows that data points concentrated roughly in 20%-50% methane conversion region, confirming the generality and prediction of modeling.
文摘提出了一个稠合型簇合物的稠合规则,讨论了唐氏拓扑结构规则和Mingos稠合规则的推广,扩大了两个稠合规则的应用范围。研究了在稠合型簇合物中Teo的C2模型与Mingos稠合规则、推广的唐氏拓扑结构规则和本文提出的稠合规则之间的关系。同时,利用提出的稠合型簇合物的稠合规则导出了超级簇合物"clusters of clusters"中原子和电子之间存在的魔数关系。
