A kind of preparation method of Y-type molecular sieve with high silicon-aluminum ratio

Abstract

The invention relates to a method for preparing a high-silica alumina ratio Y-type molecular sieve. The method is characterized in that water is added in a NaY molecular sieve for beating, polyhydroxy-alcohol is added according to the mass ratio of alcohol to the sieve at 1-20:1, a slurry A is obtained through processing at the temperature of 80-200 DEG C; the slurry A and organic base are mixed to obtain a slurry B according to the mass ratio of the alcohol to the sieve at 0.1-1:1; the slurry B and a silicon source are mixed and a mixture is aged to obtain a slurry C, by metering with SiO2, the mass ratio of the silicon source to the NaY molecular sieve is 0.1-1:1; the slurry C is subjected to hydrothermal crystallization in an enclosed reaction vessel, and the product is recovered. The method can effectively increase the silica-alumina ratio of the molecular sieve, and can make the crystallization integrity of the molecular sieve better, a structure of the molecular sieve is more stable, and the higher molecular sieve yield can be kept.

Description

technical field [0001] The invention relates to a preparation method of a Y-type molecular sieve with a high silicon-aluminum ratio. Background technique [0002] Y-type molecular sieve with faujasite crystal structure has become an important catalyst in modern industry due to its good hydrothermal stability, strong acidity and high activity. Especially in the process of petroleum refining and processing, Y-type molecular sieve is widely used . [0003] The directly synthesized Y-type molecular sieve has a silicon-aluminum ratio (SiO 2 / Al 2 o 3 ) is usually around 5.0, and can reach 5.5 when it is higher, but it is difficult to directly synthesize Y-type molecular sieves with higher silicon-aluminum ratios by conventional methods. Since the aluminum content in the Y-type molecular sieve is relatively high, and the Al-O bond is unstable under high-temperature hydrothermal conditions, it is easy to cause dealumination of the framework, which affects the integrity and stab...

AI Technical Summary

Problems solved by technology

In the gas phase method, the high temperature condition has a great influence on the molecular sieve, and the crystallinity is greatly reduced, and the by-products produced in the process are not friendly to the environment

Although the dealumination effect of the liquid phase method is better, because the dealumination agent contains F - On the one hand, it is easy to cause emission problems, and on the other hand, some fluorides formed have poor solubility and are difficult to elute, which will have a certain impact on the stability and activity of molecular sieves.

[0006] The above methods are mainly to improve the silicon-aluminum ratio and stability of the molecular sieve by removing the skeleton aluminum. Except for the hydrothermal method, the other methods are mostly at the cost of losing the yield of the molecular sieve. Even with the supplement of active silicon source However, the yield of the overall molecular sieve is still reduced, so it not only causes the waste of aluminum sources but also may cause environmental pollution; and although the hydrothermal method has no loss of yield, the existence of non-framework aluminum and the loss of crystallinity are also a problem. unfavorable factors