提高细晶粒Y型分子筛的结构稳定性及其裂化性能的研究

STUDY ON STABILIZATION AND CRACKING PERFORMANCE OF SMALL ZEOLITE CRYSTALLITES

在实验室研究了晶粒粒径约 0 .2～ 0 .4μm的分子筛硅 /铝比与结构稳定性之间的关系 ,提出了提高细晶粒Y型分子筛结构稳定性的关键是在提高其硅 /铝比的同时保持完整的晶体结构 ;用特殊的热 化学法制备的骨架硅 /铝比 11.7、结晶度大于 90 %的细晶粒USY分子筛具有与常规粗晶粒USY分子筛相近的结构和活性稳定性 ;与常规粗晶粒USY分子筛相比 ,细晶粒USY分子筛具有较高的裂化活性和动态活性 ,有更强的渣油转化能力 。

The relation between Si/Al ratio and structural stability of small Y zeolite crystallites (0.2- 0.4 μm) was studied in the laboratory. It was proposed that the key for increasing the structural stability of Y zeolite was maintaining the crystallite structure simultaneously with raising the Si/Al ratio. A special method was employed for combining the thermal treatment with a chemical treatment to prepare the small crystallites with a Si/Al ratio of 11.7 and a crystallinity of higher than 90%, which still kept the structural stability and activity stability close to the conventional USY zeolite crystallites. In comparison with the conventional USY zeolite crystallites, the small Y-zeolite crystallites exhibited both of higher cracking activity and dynamic activity with stronger bottoms crackability, as well as better selectivity of valued product yields.