Small crystal particle Y-shaped molecular sieve and preparation method thereof

Abstract

The invention discloses a small crystal particle Y-shaped molecular sieve and a preparation method thereof. The property of the small crystal particle Y-shaped molecular sieve is as follows: the molar ratio of Si, O2 / Al2O3 is 10.0-120.0, the cell parameters are 2.420-2.445 nm, the crystallization retention is larger than 95 percent, and B acid / L acid is above 7.0. Due to higher raw material thermal and hydrothermal stability, higher silicon-aluminum ratio, good stability and uniform framework silicon-aluminum structure, the small crystal particle NaY molecular sieve can ensure the framework continuity of the molecular sieve, reduce the collapse possibility of the framework structure and maximally keep the integrity of a silicon-aluminum-oxygen structure in the modification, namely in the ammonia exchange, ammonium fluorosilicate dealumination and silicon reinsertion, hydro-thermal treatment, aluminum salt and acid mixed water solution treatment process, thereby having high crystallization retention. The Y-shaped molecular sieve can be taken as an active component of a hydrocracking catalyst, thereby improving the activity of the catalyst, the selectivity of the molecular sieve and the product quality.

Description

Technical field [0001] The invention relates to a Y-type molecular sieve and a preparation method thereof, in particular to a small-crystalline Y-type molecular sieve and a preparation method thereof. Background technique [0002] Currently in the field of heavy oil cracking, molecular sieves that can be used as cracking active components include Y-type, β-type and ZSM, among which Y-type molecular sieves are most commonly used. At present, the methods of industrial production of Y-type molecular sieves basically use the directing agent method proposed by GRACE in USP 3639099 and USP 4166099. The crystal grains of ordinary Y-type molecular sieves are generally about 1000 nm, and the crystal grains are relatively large. The pores are relatively long and the diffusion resistance is large. It is difficult for macromolecules to enter the pores for reaction, and the products after the reaction are also difficult to diffuse out, so its cracking activity and the selectivity of the targe...

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Problems solved by technology

CN1382632A discloses a super-stabilizing method of small-grain Y-type zeolite, which is obtained by contacting the dry gas of silicon tetrachloride with small-grain NaY zeolite and washing it. Stability is just relatively poor, and this inventive method adopts the mode of vapor phase dealumination of silicon to process molecular sieve simultaneously, and this makes the thermal and hydrothermal stability of product worse, and activity is low; Small, high energy consumption and other disadvantages

Using aluminum salt alone can also partially remove the non-framework aluminum formed after hydrothermal treatment, but because the pH value of the aluminum salt solution is generally between 2 and 3, it is not enough to remove a large amount of non-framework aluminum, so that part of the aluminum in the micropores The difficult-to-remove non-skeleton aluminum remains in the molecular sieve, which causes partial acid centers of the molecular sieve to be masked, and also affects the distribution of B acid and L acid, making it difficult to maximize the cracking performance of the molecular sieve

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