Preparation method for hydrocracking catalyst

Abstract

The invention discloses a preparation method for a hydrocracking catalyst. The method comprises the following steps: subjecting a small-grain Y type molecular sieve, amorphous silicon-aluminum and a binder prepared from alumina to mechanical mixing and molding and then carrying out drying and roasting so as to prepare a catalyst carrier; and loading a hydrogenation active metal component on the catalyst carrier and then carrying out drying and roasting so as to prepare the catalyst. According to the method, a NaY type molecular sieve raw material with a high silica-alumina ratio, a high degree of crystallization and good stability is employed and successively undergoes ammonium exchange, primary hydro-thermal treatment, treatment with an alkali-containing solution, secondary hydro-thermal treatment and treatment with a mixed solution of acid and an ammonium salt; and the obtained small-grain Y type molecular sieve has a high SiO2 / Al2O3 mol ratio and a high proportion of secondary pores, retains the stability of the molecular sieve and has a high specific surface area and a high degree of crystallization. The hydrocracking catalyst provided by the invention is applicable as a hydrocracking catalyst for high and medium oil and has good activity, medium oil selectivity and product properties.

Description

[0001] technical field [0002] The invention relates to a method for preparing a hydrocracking catalyst, more specifically, a method for preparing a hydrocracking catalyst containing small grain Y-type molecular sieves. Background technique [0003] With the increasing demand for middle distillates in the international oil market, more middle distillates need to be obtained from heavy oil, and the hydrocracking process is one of the important means of lightening heavy oil. Because the process has the characteristics of strong raw material adaptability, good product quality, flexible adjustment operation, high yield of middle distillate products, and flexible product structure, the status of hydrocracking process has become more and more important, especially for the current problems faced by our country. Due to the shortage of petroleum resources, increasingly stringent environmental protection requirements, and the structure of petroleum products that are no longer suitable...

AI Technical Summary

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. The stability is poor, and the method is to deal with molecular sieves by gas-phase dealumination and silicon supplementation, which makes the thermal and hydrothermal stability of the product worse and the activity low

In this method, the raw material needs to be treated with ammonium hexafluorosilicate for dealumination of silicon first, and then undergo hydrothermal treatment and other treatments, so as to reduce the collapse of the molecular sieve skeleton structure and improve the crystallization retention of the molecular sieve. After treatment with ammonium hexafluorosilicate for dealumination and silicon supplementation, due to the isomorphic substitution of silicon and aluminum, the molecular sieve silicon oxide aluminum structure is relatively complete, and then hydrothermal treatment will form less secondary pores, and the proportion of secondary pores is low. Catalyst molecular sieve component, medium oil yield is low

[0008] In the preparation process of the existing method, small-grain NaY molecular sieves, silicon and aluminum are easily lost, the utilization rate of silicon is low, and the distribution of silicon and aluminum is not uniform, and it is easy to appear agglomeration, so the existing methods still cannot prepare small-grain NaY molecular sieves with high silicon-aluminum ratio and good thermal stability and hydrothermal stability

After subsequent modification, small-grain Y-type molecular sieves with complete structure, high crystallinity and more secondary pores cannot be obtained. As the cracking component of the catalyst, the yield of medium oil is low