ZSM-5分子筛的脱硅改性及加氢改质性能

Desilication modification of ZSM-5 zeolite and its catalytic properties in hydro-upgrading

考察了水热与碱联合处理过程中两者的先后顺序对ZSM-5分子筛酸性和孔结构的影响,并与单独的水热和碱处理进行了比较。结果表明,水热后的碱处理对ZSM-5分子筛具有骨架脱硅、骨架补铝和清除非骨架铝物种三重作用,而碱处理后的水热处理具有骨架脱铝和部分骨架稳定化双重作用。与先水热处理再碱处理相比,先碱处理后的水热处理在优化分子筛酸性和产生介孔方面更加有效。基于水热-碱联合处理的HZSM-5分子筛所制备的催化剂对催化裂化汽油的加氢改质表现出适中的异构化活性、较高的烯烃芳构化活性以及最高的稳定性。

The effects of the sequence of the combined steaming and alkali treatments of ZSM-5 zeolite on its acidic properties and pore structure were investigated and compared with those of individual steaming treatment or alkali treatment. The results showed that the alkali treatment after steaming has triple effects on the resultant ZSM-5 zeolite, i. e. desilication, realumination and removal of extra-framework aluminum; whereas the steaming after alkali treatment has binary effects, i.e. dealumination and stabilization. Compared with the alkali treatment after steaming, the steaming after alkali treatment is more effective in adjusting the zeolite acidic properties and creating mesopores. The catalyst derived from ZSM-5 zeolite modified via the combined alkali treatment and steaming exhibits moderate isomerization activity, higher aromatization activity and superior stability in the hydro-upgrading of fluid catalytic cracking gasoline.