CoZr/AC@ZSM-5核壳结构催化剂费-托合成反应特性

摘要

The core-shell structured CoZr/AC@ZSM-5 catalysts were prepared with hydrothermal synthesis, and then they were characterized by scanning electron microscope, X-ray Diffraction, Brunauer Emmett Teller and NH3-temperature programmed desorption methods. The catalyst performance was evaluated in a fixed-bed reactor for Fischer-Tropsch synthesis process. Compared to CoZr/AC catalyst without surrounding ZSM-5 membrane, the micro-pore structure of ZSM-5 zeolite membrane slows down the internal diffusion of syngas. Therefore, the selectivity of light hydrocarbon increases, and the selectivity of heavy hydrocarbons and alcohols decreases. The mechanism analysis indicates that the micro-pore structure of zeolite membrane facilitates the hydrogenation reactions, while it suppresses the carbon chain growth and CO insertion reactions, In addition, ZSM-5 zeolite membrane has certain hydrocracking ability.%采用水热合成法制各了核壳结构的CoZr/AC@ZSM-5催化剂,并用扫描电镜、X射线衍射仪、比表面积、孔结构测定仪和化学吸附仪等对催化剂的形貌和结构进行了表征.在固定床反应器上对其费-托合成反应的性能进行了考察.与无ZSM-5包覆的CoZr/AC催化剂相比较,核壳型催化剂分子筛膜微孔结构的存在削弱了合成气由核外至核内的扩散,低碳烃的选择性得到提高,而重质烃和醇类的生成得到抑制.反应机理分析表明,核壳型催化剂上的ZSM-5分子筛膜的微孔结构促进了加氢反应,削弱了碳链增长和CO插入反应的进行,同时该膜也具有一定的催化裂化作用.