Y type zeolites containing rare-earth and high content of silicon and method of making the same

Abstract

The RE-containing high-silicon Y-type zeolite has Si / Al ratio of 5-30, initial unit cell constant of 2.430-2.460 nm, RE content of 10-20 wt%, ratio between the balanced unit cell constant and initialunit cell constant not smaller than 0.985, and diffraction peak strength ratio I1 / I2 separately at (12.43+ / -0.06) deg and (11.87+ / -0.06) deg obtained through X ray diffraction analysis greater than 1.The zeolite is prepared through the first high stability gaseous process and the subsequent RE ion exchange process. It has optimized structure, high heat stability, high water stability, high cracking activity and good olefin reducing performance.

Description

technical field [0001] The invention relates to a Y-type zeolite and a preparation method thereof, more specifically, a structure-optimized rare earth-containing high-silicon Y-type zeolite and a preparation method thereof. Background technique [0002] In order to improve the activity and structural stability of Y-type zeolite, the active component of catalytic cracking catalysts, researchers have devoted themselves to introducing rare earth into high-silica Y zeolite to prepare rare-earth-containing high-silica Y-type zeolite. [0003] At present, the industrial production of high-silicon Y-type zeolite mainly adopts the hydrothermal method. Rare earth-containing high-silicon Y-type zeolite can be prepared by performing multiple rare-earth ion exchanges and multiple high-temperature roasting on NaY zeolite. The disadvantages of zeolite are: because too harsh hydrothermal treatment conditions will destroy the structure of zeolite, Y-type zeolite with high silicon-alumina r...

AI Technical Summary

Problems solved by technology

Rare earth-containing high-silicon Y-type zeolite can be prepared by performing multiple rare-earth ion exchanges and multiple high-temperature roasting on NaY zeolite. The disadvantages of zeolite are: because too harsh hydrothermal treatment conditions will destroy the structure of zeolite, Y-type zeolite with high silicon-alumina ratio cannot be obtained; although the production of aluminum outside the framework is very important for improving the stability of zeolite and forming new acid centers Beneficial, but too much aluminum outside the framework reduces the selectivity of zeolite; in addition, many dealuminated holes in zeolite cannot be filled by silicon migrated from the framework in time, often resulting in lattice defects of zeolite, and the crystallization of zeolite remains degree is low, the hydrothermal stability of the prepared rare earth-containing high-silicon Y-type zeolite is poor, showing that the initial unit cell is not easy to shrink, and the equilibrium unit cell constant is low (the ratio of the equilibrium unit cell constant and the initial unit cell constant is lower than 0.984 )

[0008] But, the preparation method of the rare earth high silicon Y-type zeolite disclosed in CN 1382525A, CN1683245A, in SiCl 4 In the process of dealumination and silicon supplementation, a large amount of rare earth ions are lost while removing sodium. In order to maintain a high rare earth content in the product, a very high content of rare earth must be introduced into the raw material, which has resulted in the loss of rare earth ions. Serious waste

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