This research investigates how combining forced periodic operation with spatially distributed catalyst activity can enhance heterogeneous catalytic processes. It focuses on analyzing reaction-diffusion phenomena within porous catalyst pellets. These pellets exhibit a Gaussian distribution of active sites, and the study investigates how externally forced periodic variations in bulk reactant concentration and temperature affect the reaction process. The paper establishes a mathematical model for a non-isothermal reaction based on Langmuir-Hinshelwood kinetics. This model is then transformed into its dimensionless form for numerical analysis. Numerical simulations are employed to investigate the impact of various parameters on the concentration and temperature profiles within the pellet, as well as on the pellet productivity. These parameters include the position and width of the Gaussian distribution of active sites, the Thiele modulus, the mass and heat Biot numbers, the Arrhenius number for reaction, the energy generation function, the ratio of characteristic times for diffusion and heat conductivity, and frequencies and amplitudes of periodic variations. The simulations reveal complex relationships between the spatial and temporal profiles of concentration and temperature within the pellets. Using porous granules with a non-uniform catalyst activity profile alongside forced periodic operations for reaction-diffusion processes enables higher productivity compared to granules with a uniform activity profile and subject to the steady-state operation. This study demonstrates the potential for optimizing catalytic processes in porous pellets with non-uniform activity profiles under forced periodic operation, offering valuable insights into enhancing process efficiency.

中文翻译：

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强制周期操作下具有高斯活性分布的催化剂颗粒与 Langmuir-Hinshelwood 动力学的反应


本研究调查了将强制周期性操作与空间分布的催化剂活性相结合如何增强非均相催化过程。它侧重于分析多孔催化剂颗粒内的反应扩散现象。这些沉淀表现出活性位点的高斯分布，该研究调查了本体反应物浓度和温度的外部强迫周期性变化如何影响反应过程。该论文建立了一个基于 Langmuir-Hinshelwood 动力学的非等温反应数学模型。然后将该模型转换为无量纲形式进行数值分析。采用数值模拟来研究各种参数对颗粒内浓度和温度曲线以及颗粒生产率的影响。这些参数包括活性位点高斯分布的位置和宽度、Thiele 模量、质量和热 Biot 数、反应的 Arrhenius 数、能量产生函数、扩散和热导率的特征时间之比以及周期性变化的频率和振幅。模拟揭示了颗粒内浓度和温度的时空分布之间的复杂关系。与具有均匀活性分布并处于稳态操作的颗粒相比，使用具有不均匀催化剂活性分布的多孔颗粒以及反应扩散过程的强制周期性操作可以提高生产率。本研究证明了在强制定期操作下优化活性分布不均匀的多孔颗粒中的催化过程的潜力，为提高工艺效率提供了有价值的见解。