A kind of prolific middle distillate hydrocracking catalyst and preparation method thereof

Abstract

The invention discloses a productive middle-distillate hydrocracking catalyst and a preparation method thereof. The catalyst comprises the following ingredients (by weight): 55-85% of a carrier containing modified Y molecular sieve and 15-45% of active metal metered on the basis of oxide. The preparation method of the catalyst comprises the following contents: uniformly mixing modified Y molecular sieve and amorphous silica-alumina and/or alumina, adding dilute nitric acid and carrying out extrusion moulding after slurry is formed, drying, and roasting to obtain a carrier containing modified Y molecular sieve; impregnating the carrier by the use of a impregnation liquid containing VIII group and/or VIB group metal, drying the impregnated carrier and roasting so as to obtain the hydrocracking catalyst. By the use of the catalyst, selectivity of produced middle-distillate and diesel quality are obviously improved, and stability of the catalyst is raised.

Description

technical field [0001] The invention relates to a hydrocracking catalyst and its preparation method, in particular to a prolific middle distillate oil hydrocracking catalyst and its preparation method. Background technique [0002] Hydrocracking technology has the characteristics of strong adaptability to raw materials, great flexibility in production operations and product plans, and good product quality. It can directly convert various heavy and low-quality feedstocks into high-quality jet fuel, diesel, and lubricating oil base materials that are urgently needed by the market. As well as chemical naphtha and tail oil steam cracking raw materials for ethylene production, it has become one of the most important heavy oil deep processing processes in modern oil refining and petrochemical industries, and has been increasingly widely used at home and abroad. Especially in recent years, with the increasing processing proportion of heavy and low-quality high-sulfur crude oil and ...

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Problems solved by technology

[0004] Chinese patent CN96120016.2 discloses a Y-type molecular sieve with high silicon crystallinity and its preparation method. 4 NaY is used as the reaction raw material. First, ammonium hexafluorosilicate is used to dealuminate silicon, then perform hydrothermal treatment, and finally treat with aluminum salt solution. The obtained Y molecular sieve maintains a high degree of crystallinity while being deeply dealuminated. However, The pore volume of the obtained modified Y molecular sieve should be low, which is not conducive to the contact and reaction of macromolecular reactants;

[0005] U.S. Patent No. 4,036,739 discloses a hydrocracking method, which discloses a method for modifying Y-type molecular sieves. At a temperature of 315 to 899 ° C, and at least 0.5 psi water vapor is contacted for a period of time to obtain modified Y The unit cell constant of the molecular sieve is 2.440~2.464nm; the treated Y molecular sieve is subjected to ammonium exchange to obtain an intermediate with a sodium content of less than 1%; then, a modified Y molecular sieve with a unit cell constant less than 2.440nm is obtained. The process is relatively harsh, so that the crystallinity of the obtained modified Y molecular sieve is severely damaged, and the crystallinity is low, which affects its performance

[0006] The existing Y-type molecular sieve modification technology has the problems of dealumination depth, silicon-aluminum ratio, secondary pore volume and crystallinity. When the dealumination depth increases, the silicon-aluminum ratio increases, and the secondary pore structure increases, the crystallinity tend to be more destructive; vice versa

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