Pt/ZSM-22催化剂酸性原位调控及加氢异构性能

In-situ acid regulation and hydroisomerization performance of Pt/ZSM-22 catalyst

采用水热法合成ZSM-22分子筛并制备催化剂载体,通过负载贵金属Pt,制备出高分散Pt/H-ZSM-22加氢异构催化剂。以n-C_(12)为原料,考察催化剂的加氢异构性能,在正构烷烃加氢异构反应过程中,通过在原料油中引入一定量含氮物种二正丁胺,使其在催化剂酸性位上发生化学吸附,对催化剂酸性进行原位调控,考察催化剂性能变化。结果表明,随着反应温度提高,酸性调控后的Pt/N-ZSM-22液体收率下降缓慢,且转化率达到85%以上时,Pt/N-ZSM-22的异构选择性比Pt/H-ZSM-22高出约3个百分点。酸性调控后的Pt/N-ZSM-22可通过提高反应温度进行含氮物种脱附,恢复催化剂酸位点的可接近性。采用酸性调控后的催化剂用于以加氢裂化尾油为原料的加氢异构反应,基础油收率均较调控前催化剂有明显提高。

A hydrothermal method was used to synthesize ZSM-22 molecular sieve and prepare a catalyst carrier.By loading precious metal Pt,a highly dispersed Pt/H-ZSM-22 hydroisomerization catalyst was prepared.Using n-C_(12) as feedstock,the hydroisomerization performance of the catalyst was investigated.By introducing a certain amount of nitrogen-containing species in the reaction process,the acid of catalyst was adjusted in the hydroisomerization reactor,and the change of the catalyst performance was investigated.The results showed that,as the reaction temperature increased,the liquid yield of Pt/N-ZSM-22 decreased slowly,and the isomerization selectivity of Pt/N-ZSM-22 were about 3 percentage points higher than Pt/H-ZSM-22 under the same conversion rate above 85%.The acid sites of Pt/N-ZSM-22 catalyst which was absorbed by the nitrogen-containing species can also be restored during raising the reaction temperature.The catalyst after acid regulation was used for hydroisomerization of the hydrocracking UCO,and the base oil yield was significantly higher than the catalyst before regulation.