A kind of modification method of Y-type molecular sieve

Abstract

The invention provides a Y type molecular sieve modification method. The Y type molecular sieve modification method is characterized by comprising the steps that (1) a NaY molecular sieve is activated for 1-10 h through polyhydroxy alcohol at 80-200 DEG C to obtain slurry A, wherein the alcohol-sieve weight ratio is (1-20):1; (2) the slurry A is cooled and mixed with organic alkali to obtain slurry B, wherein the alkali-sieve weight ratio is (0.1-1):1; (3) a silicon source and an aluminum source are sequentially added into the slurry B, and the mixture is aged to obtain slurry C, wherein the weight ratio of the silicon source (in terms of SiO2) to the NaY molecular sieve is (0.1-1):1, and the weight ratio of the aluminum source (in terms of Al2O3) to the silicon source (in terms of the SiO2) is (0.3-0.5):1; and (4) the slurry C is subjected to hydrothermal crystallization, and a product is recovered. By adoption of the Y type molecular sieve modification method, the silicon-aluminum ratio of a molecular sieve skeleton can be remarkably increased, meanwhile, the acid site number of the molecular sieve is increased, and the cracking activity of the molecular sieve is improved.

Description

technical field [0001] The invention relates to a method for modifying a Y-type molecular sieve. Background technique [0002] Breck successfully synthesized Y-type molecular sieve in the 1960s. After half a century of research and development, Y-type molecular sieve has been widely used in modern industry. Y-type molecular sieve is a kind of aluminosilicate with faujasite structure (FAU), which is a very important kind of microporous catalytic material, with uniform pore structure, high thermal and hydrothermal stability and strong It is acidic and has high catalytic activity, so it is widely used in petroleum refining and petroleum processing, especially in catalytic cracking and hydrocracking, and has become an extremely important cracking active component in cracking agents. [0003] In the catalytic cracking reaction process, according to the carbon ion reaction mechanism, the molecular sieve should have a strong B acid center to ensure a high cracking activity. For t...

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Problems solved by technology

However, it is unavoidable that during the ultra-stabilization process, due to the dealumination of the skeleton, the Si-O-Al bonding structure is reduced, resulting in the loss of the B acid center, and because the charges in the Si-O-Si structure are balanced, there is no acidity. , thus leading to a decrease in the total acid content of the molecular sieve, affecting the cracking activity or selectivity

Therefore, the ultra-stabilization process cannot meet the requirements of high stability and high number of acid sites at the same time.

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