Although great progress has been made in the synthesis of hierarchically structured zeolites (HSZs), the optimal design of HSZs is still very challenging due to the lack of mathematical models. This work proposes a multiscale model that is able to describe mass transfer and reaction at crystal, pellet, and reactor levels, by directly coupling model equations at two neighboring levels. Two types of HSZ particles are considered, and n-hexane isomerization catalyzed by Pt/ZSM-5 is taken as a model reaction system. The results show that the diffusion limitations in both micropores and macro-/meso-pores can significantly reduce the conversion at reactor level. The trade-off between diffusion limitations and quantity of catalytic materials determines the optimal structure of HSZ particles. The optimized HSZ particles can be 52.9–1021.4% larger in conversion than their conventional counterparts. This work provides a powerful model and some useful guidance for the design of industrial zeolite catalysts.

中文翻译：

---

正己烷异构化分级结构ZSM-5沸石的优化设计

尽管在分级结构沸石（HSZs）的合成方面取得了很大进展，但由于缺乏数学模型，HSZs的优化设计仍然非常具有挑战性。这项工作提出了一个多尺度模型，该模型能够通过直接耦合两个相邻级别的模型方程来描述晶体、颗粒和反应器级别的传质和反应。考虑了两种类型的 HSZ 粒子，n以Pt/ZSM-5催化的-己烷异构化反应为模型反应体系。结果表明，微孔和大/中孔中的扩散限制可以显着降低反应器水平的转化率。扩散限制和催化材料数量之间的权衡决定了 HSZ 颗粒的最佳结构。优化后的 HSZ 颗粒的转化率比传统颗粒大 52.9-1021.4%。这项工作为工业沸石催化剂的设计提供了一个强大的模型和一些有用的指导。