NaY type molecular sieves and preparation method therefor

Abstract

The invention discloses NaY type molecular sieves and a preparation method therefor. The molecular sieves have the properties as follows: the mesoporous distribution is 2nm to 6nm, the pore volume of mesopores accounts for 10% to 70% that of micropores and preferably is 20% to 60%, and the specific surface area is 750m<2>/g to 950m<2>/g and preferably is 800m<2>/g to 920m<2>/g; the external specific surface (mesoporous specific surface) is 50m<2>/g to 200m<2>/g and preferably is 100m<2>/g to 160m<2>/g; and the pore volume is 0.40ml/g to 0.60ml/g and preferably is 0.42ml/g to 0.55ml/g. The preparation method comprises the following steps: (1) uniformly mixing sodium hydroxide, an aluminum source, water glass and water, and carrying out aging, so as to obtain a directing agent; and (2) uniformly mixing the directing agent obtained in the step (1), roasted amorphous silica-alumina, sodium hydroxide, water and water glass so as to obtain a gel system, then, carrying out low-temperature crystallization and high-temperature crystallization, and carrying out cooling, solid-liquid separation and drying, thereby obtaining the NaY type molecular sieves. The molecular sieves disclosed by the invention have neat mesoporous distribution; the preparation method is simple in operation and good in repeatability; and the molecular sieves have a broad application prospect in a hydrocracking reaction.

Description

technical field [0001] The invention belongs to the field of molecular sieve synthesis, and in particular relates to a NaY type molecular sieve and a preparation method thereof. Background technique [0002] Y-type zeolite is formed by faujasite cages interpenetrating with each other along three crystal axis directions through twelve-membered rings. It is an excellent catalyst active component, not only has high cracking activity, but also has good selectivity. The discovery and use of Y-type zeolite has epoch-making significance in the field of catalysis. [0003] As crude oil becomes increasingly heavy and inferior, catalytic cracking and hydrocracking of heavy oil and light oil are important processes for deep processing of heavy oil to prepare light oil. Therefore, we put forward higher requirements on the catalytic performance of the catalyst. Microporous zeolite materials are widely used in petroleum refining and petrochemical fields due to their regularly arranged m...

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Problems solved by technology

However, ZSM-5 contains MCM-41, and what is obtained is actually a mixture of ZSM-5 and MCM-41 that has been sieved. The catalytic effect and selectivity of sieved are far inferior to pure ZSM-5.

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