A global kinetic model for the oxidative dehydrogenation of ethane over mixed metal oxide catalysts at supra-ambient pressures
A global kinetic model for the oxidative dehydrogenation of ethane over mixed metal oxide catalysts at supra-ambient pressures
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DOI：
10.1016/j.cej.2022.136605
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发表时间：
2022-05-17
影响因子：
15.1
通讯作者：
Bollini, Praveen
中科院分区：
文献类型：
--
作者：
Chen, Jiakang;Sun, Zhe;Bollini, Praveen
与传统的蒸汽裂化工艺不同，乙烷的氧化脱氢（ODHE）可以潜在地用于在超环境压力下生产乙烯，从而减少反应器占地面积并减轻（解）压缩能量需求。全球动力学模型，捕获动力学特征的期望和不期望的反应物和产物的压力在一个扩展的范围内是缺乏的，尽管明确的依赖比较反应器设计评估对这样的模型。我们在此报告的全球动力学模型，占所有6个流行的反应网络步骤的速率（603和703 K之间），扩展到6巴的总压力，并解释了广泛的微分和积分动力学功能测量超过MoVTeNbOx催化剂。H2O2介导的溶解过程，使低温下的测量，在本研究中使用的扩展的压力范围内的证据显着覆盖率的减少网站的贡献，可以解释为确定乙烷与氧的摩尔比。解释测量的动力学特征需要调用一个氧池存在于准平衡与气相氧是不同的身份从晶格氧，只有后者是完全负责氢提取步骤的周转产生乙烯，而不是考克斯。我们演示了如何简化的全球动力学模型，采用幂律速率表达式的不希望的反应，并排除产品的抑制作用的整个反应网络是足以解释两个共同饲料数据，以及在没有产品共同饲料评估的微分和积分功能。所提出的动力学模型可以采用在比较评估的高压ODHE反应器配置操作非等温，特别是那些进行高灵敏度的贡献，从高度放热的总氧化反应。
Oxidative dehydrogenation of ethane (ODHE), unlike traditional steam cracking processes, can potentially be used to produce ethene at supra-ambient pressures, thereby reducing reactor footprint and alleviating (de) compression energy requirements. Global kinetic models that capture kinetic features of both desired and undesired reactions over an extended range of reactant and product pressures are lacking despite the clear reliance of comparative reactor design assessments on such models. We report herein a global kinetic model that accounts for the rates (between 603 and 703 K) of all 6 of the prevalent reaction network steps, extends up to 6 bar total pressure, and explains a broad set of differential and integral kinetic features measured over MoVTeNbOx catalysts. H2O2-mediated dissolution procedures enable low-temperature measurements which under the extended pressure ranges used in this study evidence significant coverages of reduced sites the contributions of which can be interpreted as being determined by ethane to oxygen molar ratios. Explaining measured kinetic features require invoking an oxygen pool present in quasi-equilibrium with gas phase oxygen that is distinct in identity from lattice oxygens, only the latter of which are wholly responsible for hydrogen abstraction steps in turnovers producing ethene, not COx. We demonstrate how a simplified global kinetic model that employs power law rate expressions for undesired reactions and excludes product inhibitory effects for the entirety of the reaction network is sufficient to explain both co-feed data as well as differential and integral features evaluated in the absence of product co-feeds. The proposed kinetic model can be employed in comparative assessments of highpressure ODHE reactor configurations operating non-isothermally, especially those carrying a high sensitivity to contributions from highly exothermic total oxidation reactions.