Preparation method of catalyst containing small-grain Y-type molecular sieve

Abstract

The invention provides a preparation method of a catalyst containing a small-grain Y-type molecular sieve. The preparation method comprises steps of mixing raw materials including a small-grain Y-type molecular sieve, alumina sol, hydrated alumina, silica sol, clay, acid and water to obtain slurry and moulding to obtain the catalyst. The preparation method is characterized in that the small-grain Y-type molecular sieve is prepared from the following steps: successively adding a guiding agent, a silicon source, an aluminium source and water into a mixing tank under synthesis conditions of a NaY molecular sieve so as to obtain a mixture A, carrying out hydrothermal crystallization on the mixture A and recovering an obtained product, carrying out ammonium exchange for sodium reduction on the product, carrying out a hydro-thermal treatment, beating, adding silica sol with pH of 2-4 and C2-C4 organic alcohols, adjusting pH to 3-6 with citric acid, fully mixing at the temperature of 80-120 DEG C, washing and drying. The catalyst prepared by the above method has good mechanical strength and has better catalytic performance.

Description

technical field [0001] The present invention relates to a preparation method of a catalyst containing Y-type molecular sieves, more specifically to a preparation method of a catalyst containing small-grain Y-type molecular sieves. Background technique [0002] In the late 1950s, Milton and Breck successfully synthesized Y-type molecular sieves. Due to the SiO in the structure of the Y-type molecular sieve 2 with Al 2 o 3 The ratio is greater than that of X-type molecular sieve, so that the thermal stability and hydrothermal stability are improved. In the early 1970s, Grace Company developed the directing agent method to synthesize NaY molecular sieves. The raw material was water glass instead of expensive silica sol. The process was simplified and the growth cycle was shortened, so that NaY molecular sieves were rapidly and widely used in petrochemical industries Petroleum cracking catalysis field. So far, among the hundreds of molecular sieves that have been developed,...

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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

Although the above two modification methods can increase the silicon-aluminum ratio of the molecular sieve skeleton, the fluoride ions introduced by the additives are difficult to elute from the slurry, and a large amount of fluoride ions remain in the liquid after the molecular sieve is washed, causing environmental problems in industrial production.

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