Array Modified Molded Alumina Supported PdAg Catalyst for Selective Acetylene Hydrogenation: Intrinsic Kinetics Enhancement and Thermal Effect Optimization,Industrial & Engineering Chemistry Research

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Array Modified Molded Alumina Supported PdAg Catalyst for Selective Acetylene Hydrogenation: Intrinsic Kinetics Enhancement and Thermal Effect Optimization
Industrial & Engineering Chemistry Research ( IF 3.8 ) Pub Date : 2021-06-04 , DOI: 10.1021/acs.iecr.1c00423
Chenglin Miao _{1,

2} , Luoyu Cai _{1,

2} , Yanfei Wang ₃ , Xingjun Xu ₁ , Jiarui Yang ₁ , Yufei He _{1,

2} , Dianqing Li _{1,

2} , Junting Feng _{1,

2}

Affiliation

High temperature calcined spherical alumina material with macroporous structure is widely used in the typical strong exothermic industrial catalytic process due to its good heat transfer ability. Aiming at the problem that its low surface area limits the dispersion of active metals, an in situ growth method is applied to fabricate an alumina array on spherical alumina, while maintaining the heat transfer advantages. Taking the as-obtained modified alumina as support, a highly dispersed PdAg catalyst for selective hydrogenation of acetylene is synthesized, which exhibits a remarkable enhanced intrinsic activity. Moreover, when the conversion of acetylene reaches 90%, the selectivity toward ethylene still remains 89%. Preferred selectivity is assigned to more isolated Pd sites as well as high electronic density, which facilitates the desorption of the resulting ethylene. More importantly, the array modified catalyst exhibits good structural stability and resistance to carbon deposition. From one aspect, the decrease of the heat production rate over a single active site is conducive to reducing the reaction heat accumulation, thereby avoiding the formation of hot spots over the catalyst, which is a necessary condition for the endothermic reaction of carbon deposition. From another point of view, both the new generated outer opening pore structure and the original macroporous structure of the molded alumina are beneficial for the heat transfer.

中文翻译：

用于选择性乙炔加氢的阵列改性模塑氧化铝负载 PdAg 催化剂：本征动力学增强和热效应优化

具有大孔结构的高温煅烧球形氧化铝材料由于其良好的传热能力，被广泛应用于典型的强放热工业催化过程。针对其低表面积限制活性金属分散的问题，采用原位生长法在球形氧化铝上制备氧化铝阵列，同时保持传热优势。以得到的改性氧化铝为载体，合成了一种高度分散的用于乙炔选择性加氢的PdAg催化剂，其固有活性显着增强。而且，当乙炔的转化率达到90%时，对乙烯的选择性仍保持在89%。优选的选择性分配给更多孤立的 Pd 位点以及高电子密度，这有利于所得乙烯的解吸。更重要的是，阵列改性催化剂表现出良好的结构稳定性和抗积碳能力。从一方面来看，单个活性位点上产热速率的降低有利于减少反应热量的积累，从而避免在催化剂上形成热点，这是积碳吸热反应的必要条件。从另一个角度来看，成型氧化铝新生成的外开孔结构和原有的大孔结构都有利于传热。单个活性位点上产热速率的降低有利于减少反应热量的积累，从而避免在催化剂上形成热点，这是积碳吸热反应的必要条件。从另一个角度来看，成型氧化铝新生成的外开孔结构和原有的大孔结构都有利于传热。单个活性位点上产热速率的降低有利于减少反应热量的积累，从而避免在催化剂上形成热点，这是积碳吸热反应的必要条件。从另一个角度来看，成型氧化铝新生成的外开孔结构和原有的大孔结构都有利于传热。

更新日期：2021-06-17

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