Preparation method of hollow USY molecular sieve

Abstract

The invention discloses a preparation method of a hollow USY molecular sieve. The preparation method comprises 1, preparing a guiding agent, 2, preparing a mixed solution from an aluminum source, water and sodium hydroxide, adding a low silica-alumina ratio NaY molecular sieve and the guiding agent obtained through the step 1 into the mixed solution, carrying out uniform stirring, carrying out constant temperature crystallization on the gel at a temperature of 90-120 DEG C for 12-72h and carrying out cooling, washing, pumping filtration and drying to obtain a Y-Y composite molecular sieve, 3, carrying out ammonium exchange on the Y-Y composite molecular sieve prepared through the step 2, 4, treating the Y-Y composite molecular sieve subjected to ammonium exchange under hydro-thermal conditions and 5, washing the composite molecular sieve subjected to hydro-thermal treatment in the step 4 to obtain the hollow USY molecular sieve. The USY molecular sieve has more exposed reaction active sites, greatly shortens a reactant diffusion distance and improves molecular sieve catalysis performances.

Description

technical field [0001] The invention relates to a preparation method of a hollow USY molecular sieve. Background technique [0002] Y-type molecular sieve is formed by octahedral molecular sieve 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. Therefore, the discovery and use of Y-type molecular sieve has epoch-making significance in the field of catalysis. [0003] Since Y-type molecular sieves with a low silicon-aluminum ratio (the molar ratio of silicon oxide to aluminum oxide is between 3 and 4.2) do not have good hydrothermal stability, they have not been widely studied and widely used in the actual synthesis process and application. attention. The high silicon-aluminum ratio Y-type molecular sieve (the molar ratio of silicon oxide to aluminum oxide is above 4.3) has good hydrothermal stability and a...

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Problems solved by technology

[0005] At the same time, the synthesis of Y with different silicon-aluminum ratios has attracted the attention of many researchers. It is generally believed that Y-type molecular sieves with low silicon-aluminum ratios (Si / Al less than 2.25) have poor hydrothermal stability and cannot be applied industrially.

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