The effect of the volume‐to‐surface (V/S) ratio on the catalytic performance of a La–Sr/CaO catalyst in a fixed bed reactor under oxidative coupling of methane (OCM) conditions is investigated by adjusting the amount of diluent in the catalyst bed. It was observed experimentally that the catalyst activity, C₂ selectivity, and C₂H₄/C₂H₆ ratio are all favored at high V/S ratios. The total void volume, available in the intraparticle and the interstitial phase, was considered. A comprehensive OCM microkinetic model, explicitly distinguishing between these two phases, allowed accounting for the observed dependence of catalytic performance on V/S ratio. The major experimentally implemented variation in interstitial volume available for reaction, provoked also changes in radical concentration profiles in intraparticle phase. Given the high reaction rates occurring at this location, the experimentally observed effects with varying the V/S ratio, are attributed to concentration and, hence, reaction rate changes occurring mainly in the intraparticle phase. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2603–2611, 2018

中文翻译：

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使用微动力学模型分析体积比对甲烷氧化偶联的影响

通过调节甲烷中的稀释剂含量，研究了体积比（V / S）对固定床反应器中La-Sr / CaO催化剂在甲烷氧化偶联（OCM）条件下的催化性能的影响。催化剂床。实验观察到催化剂活性，C ₂选择性和C ₂ H ₄ / C ₂ H ₆高V / S比率时，所有比率均受青睐。考虑了在颗粒内和间隙相中可用的总空隙体积。一个全面的OCM微动力学模型，明确区分了这两个阶段，可以解释所观察到的催化性能对V / S比的依赖性。引起反应的间隙体积的主要实验实施变化，引起了粒子内相中自由基浓度分布的变化。给定在此位置发生的高反应速率，通过实验观察到的随V / S比变化的效果归因于浓度，因此，反应速率的变化主要发生在颗粒内相中。©2018美国化学工程师学会AIChE J，64：2603–2611，2018