非均相催化剂失活机理分析

Mechanism analysis of inactivation of heterogeneous catalyst

非均相催化剂失活是石油化工催化过程中普遍存在的现象及问题,通常是因为催化剂表面被其它物质覆盖,催化位点失活而导致的。文中针对流化催化裂化(FCC)、加氢处理(HDT)和催化重整3个反应工艺,综述了其催化剂失活机理,通过分析催化剂失活原因,认为中毒、结垢、烧结、化学降解以及机械磨损等因素造成催化剂不同程度失活。FCC反应过程中生成的焦炭沉积在催化剂表面是催化重整催化剂失活的主要原因,而催化剂酸性位失活是典型的中毒失活。HDT过程中产生的H2S是导致催化剂中毒失活的主要原因,并因金属和焦炭对催化剂多孔结构的堵塞,催化剂活性会在反应初期大幅下降。

Inactivation of heterogeneous catalysts is a common phenomenon and problem in petrochemical catalysis process,which is usually caused by covering the catalyst surface by other substances,resulting in inactivation of catalytic sites.This paper reviewed the deactivation mechanism of catalysts in three reaction processes including fluidized catalytic cracking(FCC),hydrotreating(HDT)and catalytic reforming,analyzed the causes of deactivation of catalysts to conclude that poisoning,scaling,sintering,chemical degradation and mechanical wear were the main factors to cause the deactivation of catalysts in different degrees.The deposition of coke on catalyst surface during FCC reaction was the main cause of catalyst deactivation,and the acid deactivation of catalyst was a typical toxic deactivation.H_(2)S produced in the process of HDT was the main cause of catalyst poisoning and inactivation,and due to metal and coke blocking the porous structure of the catalyst,the catalyst activity reduced greatly in the initial reaction.