阅读说明：本技术 一种加氢裂化催化剂及其制备方法和应用 (Hydrocracking catalyst, and preparation method and application thereof ) 是由 高杭 杜艳泽 秦波 柳伟 董立廷 于 2019-10-28 设计创作，主要内容包括：本发明公开一种加氢裂化催化剂及其制备方法和应用,所述加氢裂化催化剂中含有改性Y-Y型分子筛,所述改性Y-Y型分子筛富含中强酸,以富含中强酸的改性Y-Y型分子筛为活性组分的加氢裂化催化剂为油品中的大分子反应提供更充足的反应空间,提高了该反应的目的产物的选择性。(The hydrocracking catalyst contains a modified Y-Y type molecular sieve, the modified Y-Y type molecular sieve is rich in medium strong acid, and the hydrocracking catalyst taking the modified Y-Y type molecular sieve rich in medium strong acid as an active component provides more sufficient reaction space for macromolecular reaction in oil products, so that the selectivity of target products of the reaction is improved.)

1. A hydrocracking catalyst characterized by: the catalyst contains a modified Y-Y type molecular sieve and active metal, and the weight of the final catalyst is 3-75 wt% of the modified Y-Y type molecular sieve; the catalyst contains 5-35 wt% of VIB group metal active metal calculated by oxide; 2 to 15 wt% of active metal of VIII group metal calculated by oxide; the modified Y-Y type molecular sieve has the following properties: SiO 2₂/Al₂O₃The molar ratio of (A) to (B) is 6-75; the specific surface area is 560 to 980m²(ii)/g; the total acid amount is 0.8-1.75 mmol/g; the amount of the strong acid is 0.60 to 1.150 mmol/g at 250 to 400 ℃.

2. The method of claim 1, wherein: based on the weight of the final catalyst, the catalyst contains 5-64 modified Y-Y type molecular sieveThe composition comprises 10-28 wt% of VIB group metal active metal calculated by oxide; the modified Y-Y type molecular sieve contains 3-10 wt% of VIII group metal active metal calculated by oxide, and has the following properties: SiO 2₂/Al₂O₃The molar ratio of (A) to (B) is 10 to 53; the specific surface area is 660 to 920m²(ii)/g; the total acid amount is 0.9-1.35 mmol/g; the amount of the strong acid is 0.65-0.9 mmol/g at 250-400 ℃.

3. The method of claim 1, wherein: the hydrocracking catalyst contains alumina and/or amorphous silicon-aluminum, and the content of the alumina and/or amorphous silicon-aluminum is 5-75 wt%, preferably 8-50 wt%, based on the weight of the final catalyst.

4. The method of claim 1, wherein: the VIB group metal is tungsten and/or molybdenum, and the VIII group metal is cobalt and/or nickel.

5. A process for the preparation of a hydrocracking catalyst according to any of claims 1 to 4, characterized in that: one of the following methods is adopted:

the method comprises the following steps:

preparing a modified Y-Y type molecular sieve;

(2) molding the modified Y-Y type molecular sieve prepared in the step (1), drying and roasting to prepare a carrier;

(3) introducing active metal into the carrier prepared in the step (2), and drying and roasting to prepare a final hydrocracking catalyst;

the method 2 comprises the following steps:

preparing a modified Y-Y type molecular sieve;

(2) kneading and molding the material containing the modified Y-Y type molecular sieve prepared in the step (1) and the active metal, drying and roasting to obtain the final hydrocracking catalyst.

6. The method of claim 5, wherein: in the method 1 or the method 2, the modified Y-Y type molecular sieve in the step (1) is prepared by the following steps: reacting NH₄Y-Y molecular sieve at pressure of 0.0Carrying out constant-temperature hydrothermal treatment for 1-4 h under the conditions of 2-0.25 MPa and the temperature of 300-850 ℃; then, carrying out constant-temperature hydrothermal treatment for 1-4 h under the conditions that the pressure is 0.26-0.80 MPa and the temperature is 300-850 ℃; finally, reducing the pressure and the temperature, adding deionized water, preparing a mixed solution with a solid-to-liquid ratio of 1: 5-1: 30 and an acid concentration of 0.1-2.0 mol/L, and stirring for 1-3 hours at the temperature of 20-100 ℃; and filtering and washing the modified molecular sieve to be neutral, and drying at 100-120 ℃ for 6-24 h to obtain the modified Y-Y type molecular sieve rich in medium-strong acid.

7. The method of claim 6, wherein: in the method 1 or the method 2, the modified Y-Y type molecular sieve in the step (1) is prepared by the following steps: reacting NH₄Carrying out thermostatic hydrothermal treatment on the Y-Y molecular sieve for 1-4 h under the conditions that the pressure is 0.05-0.20 MPa and the temperature is 400-750 ℃; then, carrying out constant-temperature hydrothermal treatment for 1-4 h at the pressure of 0.40-0.73 MPa and the temperature of 350-750 ℃.

8. The method according to claim 6 or 7, characterized in that: the NH₄Y-Y type molecular sieve SiO₂/Al₂O₃The molar ratio is 4.6-5.8, and the specific surface area is 650-960 m²/g，Na₂The content of O is 1.0wt% to 4.5 wt%.

9. The method of claim 5, wherein: in the method 1 or the method 2, the acid solution is one or more of a nitric acid solution, a hydrochloric acid solution, a sulfuric acid solution and a phosphoric acid solution.

10. The method of claim 5, wherein: in the method 1 or the method 2, the drying temperature in the step (2) is 100-120 ℃, the time is 8-24 hours, the roasting temperature is 450-550 ℃, and the time is 2-8 hours.

11. The method of claim 5, wherein: in the method 1, the active metal is introduced in the step (3) and is subjected to equal-volume impregnation or over-volume impregnation, the drying temperature after impregnation is 100-120 ℃, the time is 8-24 hours, the roasting temperature is 450-550 ℃, and the time is 2-8 hours.

12. Use of a catalyst prepared by the process of any of claims 1 to 4 in a hydrocracking reaction process, characterized in that: the reaction conditions were as follows: the reaction pressure is 2-20 MPa, the reaction temperature is 200-450 ℃, the hydrogen-oil ratio is 500-1800, and the volume airspeed is 0.5-5.0 h^-1。

Technical Field

The invention relates to a hydrocracking catalyst, a preparation method and application thereof, in particular to a hydrocracking catalyst containing a modified Y-Y type molecular sieve, and a preparation method and application thereof.

Background

Hydrocracking technology is one of the most important crude oil processing technologies in modern oil refining technology, can convert heavy and poor crude oil into high-value-added products such as lubricating oil base stock, gasoline, diesel oil, naphtha and the like, and is widely applied at home and abroad. In recent years, as the quality of crude oil becomes heavier, the S, N content is higher and higher, the content of macromolecular hydrocarbons is increased, and the market demand for clean oil products is increased, so that higher requirements on the hydrocracking process and the performance of a catalyst are provided. The hydrocracking process technology mainly carries out hydrogenation and cracking on oil products through a catalyst, and is the key in the whole process technology. And in the hydrocracking catalyst, a molecular sieve provides a cracking active center, polycyclic aromatic hydrocarbons are subjected to ring-opening conversion, and heavy crude oil is converted into a light product. Therefore, the pore structure and the pore size of the molecular sieve play a decisive role in the conversion rate of oil products in the process.

The molecular sieve is an inorganic crystal material artificially synthesized by adopting raw materials such as a silicon source, an aluminum source, an alkali source and the like, has strong acidity and hydrothermal stability and a unique pore channel structure, and is widely applied to the field of catalysis as a carrier at present. The common method for preparing the molecular sieve is a hydrothermal synthesis method, but has the problem of serious environmental pollution. In recent years, researchers have developed various green synthesis methods including a seed crystal method, a template-free method and the like by continuously optimizing and improving synthesis raw materials, preparation methods, conditions and the like, and have continuously promoted the research progress of zeolite molecular sieves. The Y-type molecular sieve is one of the most common and important molecular sieves in the field of petroleum refining, and is used as a carrier component of a hydrocracking catalyst to bear a cracking process and directly influence the reaction performance of the hydrocracking catalyst due to proper acid amount, acid strength, larger pore diameter and higher hydrothermal stability.

Framework silicon-aluminum ratio of conventionally synthesized Y-type molecular sieve is lower (SiO)₂With Al₂O₃The molar ratio = 3-4.2), the hydrothermal stability is poor, and the standard of industrial application cannot be achieved, so that the method is not generally applied. In contrast, high silica to alumina ratio Y type molecular Sieves (SiO)₂With Al₂O₃Molar ratio of>4.3) has better hydrothermal stability and acid property. The Y-type molecular sieve with high Si/Al ratio is usually obtained through post-treatment modification, and the post-treatment method has a mature method route capable of being applied industrially, and the process mainly comprises the steps of dealuminizing, desiliconizing or silicon supplementing of the molecular sieve skeleton by some treatment methods so as to achieve the purposes of improving the Si/Al ratio of the skeleton, dredging pore passages and exposing acid sites of the skeleton, wherein the commonly used method is ammonium fluosilicate dealuminizing and silicon supplementingAcid dealumination, ion exchange, heat treatment, alkali treatment, hydrothermal treatment and the like. The modified Y-type molecular sieve with high silica-alumina ratio can be used as a catalytic material carrier to be applied to the field of catalytic cracking and hydrocracking of petroleum processing, and plays a role in irreplaceable cracking.

The modification research of the Y-type molecular sieve mainly changes the framework silica-alumina ratio through a post-treatment process, thereby greatly improving the framework stability of the molecular sieve, generating a large amount of secondary mesoporous structures which are beneficial to macromolecular reaction and diffusion in the process, and effectively improving the utilization rate of the acid sites of the molecular sieve. Sun Shuhong et al use citric acid to modify Y-type molecular sieve, and use molecular sieve with high Si/Al ratio as raw material, but the modified Y-type molecular sieve has greatly reduced relative crystallinity, and the modification process is difficult to control, which is not beneficial to industrial application. Zhaitao et al, which adopts a combination of organic complexing agent and organic acid to treat Y-type molecular sieve, has a significant effect of removing non-framework aluminum from the outer surface of the molecular sieve, but the cost of the modification process is high and the recovery rate of the molecular sieve is low.

CN102198950 discloses a method for directly synthesizing NaY molecular sieve with high silica-alumina ratio without using any organic or inorganic template agent, but the synthesis process has longer period and the hydrothermal stability of the product is poor. In recent years, the combination of conventional molecular sieve modification means can significantly improve the overall performance of the molecular sieve. For example, the heat treatment or hydrothermal treatment and acid treatment are carried out on the hydrogen-type Y molecular sieve after ion exchange, so that a large number of secondary pores are obtained by dealuminizing the molecular sieve, and the hydrothermal stability of the molecular sieve is improved. The other method is to treat the Y-type molecular sieve with acid and then with alkali or alkaline salt, which can greatly improve the acid content and the secondary pore content of the molecular sieve and solve the problem of insufficient acid content caused by insufficient treatment depth in a single post-treatment process.

More attention is paid to the existing modification technology by constructing a large number of secondary holes to play a role in adjusting the pore channel structure of the molecular sieve, so that the diffusion performance of the pore channel of the molecular sieve is improved, but in the actual reaction process of hydrocracking, the molecular sieve plays a more important role in cracking, and the molecular sieve plays an acid site in cracking.

In recent years, the Y-Y type isomorphous composite molecular sieve is used as a novel carrier in the field of hydrocracking, and correspondingly, the performance of the Y-Y type isomorphous composite molecular sieve is improved in a targeted manner through a series of modification technologies, so that the application effect of the Y-Y type isomorphous composite molecular sieve in a hydrocracking catalyst is improved. Therefore, the method has important significance for further exploring the most efficient utilization of the acid site of the Y-Y type isomorphous molecular sieve by improving the modification technology.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a hydrocracking catalyst, a preparation method and an application thereof, wherein the hydrocracking catalyst contains a modified Y-Y type molecular sieve, the modified Y-Y type molecular sieve is rich in medium strong acid, and the hydrocracking catalyst taking the modified Y-Y type molecular sieve rich in medium strong acid as an active component provides more sufficient reaction space for macromolecular reaction in oil products, so that the selectivity of target products of the reaction is improved.

A hydrocracking catalyst contains a modified Y-Y type molecular sieve and active metal, and based on the weight of the final catalyst, the hydrocracking catalyst contains 3-75 wt%, preferably 5-64 wt% of the modified Y-Y type molecular sieve, and 5-35 wt%, preferably 10-28 wt%, calculated by oxides, of active metal containing VIB group metal; the modified Y-Y type molecular sieve contains 2-15 wt% of VIII group metal active metal calculated by oxide, preferably 3-10 wt%, and has the following properties: SiO 2₂/Al₂O₃The molar ratio of (A) is 6-75, preferably 10-53; the specific surface area is 560 to 980m²Per g, preferably 660 to 920m²(ii)/g; the total acid amount is 0.8-1.75 mmol/g, preferably 0.9-1.35 mmol/g; the amount of the strong acid is 0.60 to 1.150 mmol/g, preferably 0.65 to 0.9 mmol/g, at 250 to 400 ℃.

In the method, the hydrocracking catalyst further contains alumina and/or amorphous silicon-aluminum, and the content of the alumina and/or amorphous silicon-aluminum is 5-75 wt%, preferably 8-50 wt%, based on the weight of the final catalyst.

In the above process, the group VIB metal is preferably tungsten (W) and/or molybdenum (Mo), and the group VIII metal is preferably cobalt (Co) and/or nickel (Ni).

A preparation method of a hydrocracking catalyst adopts one of the following methods:

the method comprises the following steps:

(1) preparing a modified Y-Y type molecular sieve;

(2) molding the modified Y-Y type molecular sieve prepared in the step (1), drying and roasting to prepare a carrier;

(3) and (3) introducing active metal into the carrier prepared in the step (2), and drying and roasting to obtain the final hydrocracking catalyst.

The method 2 comprises the following steps:

(1) preparing a modified Y-Y type molecular sieve;

(2) kneading and molding the material containing the modified Y-Y type molecular sieve prepared in the step (1) and the active metal, drying and roasting to obtain the final hydrocracking catalyst.

In the method 1 or 2, the modified Y-Y molecular sieve in the step (1) is prepared as follows: reacting NH₄Carrying out constant-temperature hydrothermal treatment on the Y-Y molecular sieve for 1-4 h under the conditions that the pressure is 0.02-0.25 MPa, preferably 0.05-0.20 MPa, the temperature is 300-850 ℃, and preferably 400-750 ℃; taking out, and continuously carrying out constant-temperature hydrothermal treatment for 1-4 h at the pressure of 0.26-0.80 MPa, preferably 0.40-0.73 MPa, the temperature of 300-850 ℃ and preferably 350-750 ℃; adding deionized water into the sample subjected to pressure reduction and temperature reduction treatment, preparing a mixed solution with a solid-to-liquid ratio of 1: 5-1: 30 and an acid concentration of 0.1-2.0 mol/L, and stirring for 1-3 hours at the temperature of 20-100 ℃; and filtering and washing the modified molecular sieve to be neutral, and drying at 100-120 ℃ for 6-24 h to obtain the modified Y-Y type molecular sieve rich in medium-strong acid.

NH used in the above method 1 or 2₄The Y-Y type molecular sieve is prepared by the prior art, wherein, SiO₂/Al₂O₃The molar ratio is 4.6-5.8, and the specific surface area is 650-960 m²/g，Na₂The content of O is 1.0wt% to 4.5 wt%.

In the above method 1 or method 2, a conventional NH₄The preparation process of the Y-Y type molecular sieve is as follows: preparing 0.5-3.0 mol/L ammonium salt solution, wherein the ammonium salt can be ammonium nitrate, ammonium chloride and ammonium sulfateThe one or more of (1) and (2) adding the NaY-Y type molecular sieve into the ammonium salt solution, stirring for 0.5-5 hours at the temperature of 60-95 ℃, taking out, and drying for 8-24 hours.

In the method 1 or 2, the acid solution is one or more of inorganic acids such as nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, and the like.

In the above method 1 or method 2, an adhesive, an extrusion aid, a peptizing agent, or an auxiliary agent may be added in the forming process in the step (2), and the peptizing agent may be one or more selected from organic acids such as citric acid, acetic acid, oxalic acid, and the like.

In the method 1 or the method 2, the drying temperature in the step (2) is 100-120 ℃, the time is 8-24 hours, the roasting temperature is 450-550 ℃, and the time is 2-8 hours.

In the method 1, the active metal is introduced in the step (3) by adopting a dipping method, the active metal can be dipped in an equal volume or through volume, the drying temperature after dipping is 100-120 ℃, the time is 8-24 hours, the roasting temperature is 450-550 ℃, and the time is 2-8 hours.

The catalyst is used in the hydrocracking reaction process, and the reaction conditions are as follows: the reaction pressure is 2-20 MPa, the reaction temperature is 200-450 ℃, the hydrogen-oil ratio is 500-1800, and the volume airspeed is 0.5-5.0 h^-1。

The method adopts a pressure-swing hydrothermal treatment technology, removes aluminum atoms at different positions of a framework in the modification process of the Y-Y type molecular sieve, and integrally controls the acid properties, particularly the acid strength, of the Y-Y type molecular sieve. The steam concentration in the hydrothermal treatment device is regulated and controlled by regulating the low pressure and the high pressure, the water molecular weight of the environment around the aluminum atoms of the molecular sieve framework is further controlled, and the aluminum atoms with different binding energy are respectively removed. The weak strength and high strength acid sites which are not beneficial to the reaction are removed in a targeted manner, the aim of enriching the medium and strong acid which is beneficial to the reaction is achieved, particularly, the shell layer nano small particle Y-shaped molecular sieve forms more effective active sites, and the catalytic performance of the shell layer nano small particle Y-shaped molecular sieve is greatly improved. The Y-Y type molecular sieve modified by the method can be directly used for preparing a carrier of a hydrocracking catalyst, and the selectivity of a target product is effectively improved. Compared with the existing modification method, the modified Y-Y type molecular sieve prepared by the method has the advantages that the acid content (250-400 ℃) of the medium strong acid is remarkably increased under the condition that the silicon-aluminum ratio is the same, and the application prospect is good.

Drawings

Figure 1 is an XRD spectrum of the Y-type molecular sieve prepared in example 2.

Detailed Description

The following examples further illustrate the preparation of the present invention, but are not to be construed as limiting the process of the present invention. NH is adopted in the preparation process₄The Y-Y type molecular sieve has the following properties: SiO 2₂/Al₂O₃Has a molar ratio of 5.3 and a specific surface area of 839m²(ii) in terms of/g. In the following examples and comparative examples,% are mass% unless otherwise specified, and NH₄The Y-Y type molecular sieve is prepared by the following method: preparing 0.5-3.0 mol/L ammonium salt solution, wherein the ammonium salt can be one or more of ammonium nitrate, ammonium chloride and ammonium sulfate, putting the NaY-Y type molecular sieve into the ammonium salt solution, setting the temperature to be 60-95 ℃, stirring for 0.5-5 hours, taking out, and drying for 8-24 hours.

In the method of the present invention, the determination method of the total acid content and the content of the medium and strong acids is a conventional determination method, and refers to the method disclosed in article "influence of mesoporous P zeolite acid properties and pore structure on catalytic diesel oil hydrogenation ring-opening performance", published in "Petroleum institute (Petroleum processing)" 2018, volume 34, No. 1 by Wangjian et al: pyridine infrared characterization is adopted to modify acidic Bronsted acid and Lewis acid on the surface of the Y-Y type molecular sieve, and the determination range of the infrared spectrum is 4000cm^-1~400cm^-1. The B acid position and the L acid position of the molecular sieve are respectively 1400-1700 cm^-11540 cm in range^-1And 1450 cm^-1The characteristic peak of (A) is subjected to qualitative analysis and quantitative calculation.

Example 1

Reacting NH₄Carrying out constant-temperature hydrothermal treatment on a Y-Y type molecular sieve at 0.08MPa and 450 ℃ for 1h, carrying out constant-temperature hydrothermal treatment at 0.30MPa and 640 ℃ for 2h, carrying out pressure reduction and temperature reduction, placing a sample in a nitric acid solution with a solid-to-liquid ratio of 1:10 and a concentration of 0.60mol/L, stirring at 80 ℃ for 2h, taking out, filtering, washing to be neutral,drying at 110 deg.c for 18 hr to obtain modified Y-Y type molecular sieve rich in medium and strong acid. The specific properties of the modified Y-Y molecular sieve are shown in Table 1.

Example 2

Reacting NH₄Carrying out constant-temperature hydrothermal treatment on the Y-Y type molecular sieve at 0.15MPa and 550 ℃ for 1h, carrying out constant-temperature hydrothermal treatment at 0.40MPa and 550 ℃ for 2h, reducing the pressure and the temperature, placing the sample in a nitric acid solution with a solid-to-liquid ratio of 1:20 and a concentration of 1.0mol/L, stirring at 70 ℃ for 1h, taking out, filtering, washing to be neutral, and drying at 100 ℃ for 24h to obtain the modified Y-Y type molecular sieve rich in medium-strong acid. The specific properties of the modified Y-Y molecular sieve are shown in Table 1.

Example 3

Reacting NH₄And carrying out constant-temperature hydrothermal treatment on the Y-Y type molecular sieve at 0.20MPa and 350 ℃ for 3h, carrying out constant-temperature hydrothermal treatment at 0.50MPa and 450 ℃ for 3h, reducing the pressure and the temperature, placing the sample in a hydrochloric acid solution with the solid-to-liquid ratio of 1:15 and the concentration of 1.5mol/L, stirring at 60 ℃ for 1h, taking out, filtering, washing to be neutral, and drying at 110 ℃ for 18 h to obtain the modified Y-Y type molecular sieve rich in medium-strong acid. The specific properties of the modified Y-Y molecular sieve are shown in Table 1.

Example 4

Reacting NH₄Carrying out constant-temperature hydrothermal treatment on the Y-Y type molecular sieve at 0.10MPa and 550 ℃ for 1h, carrying out constant-temperature hydrothermal treatment at 0.45MPa and 650 ℃ for 1h, reducing the pressure and the temperature, placing the sample in a sulfuric acid solution with the solid-to-liquid ratio of 1:16 and the concentration of 0.60mol/L, stirring at 50 ℃ for 2h, taking out, filtering, washing to be neutral, and drying at 120 ℃ for 12 h to obtain the modified Y-Y type molecular sieve rich in medium-strong acid. The specific properties of the modified Y-Y molecular sieve are shown in Table 1.

Example 5

Reacting NH₄Carrying out constant-temperature hydrothermal treatment on the Y-Y type molecular sieve at 0.08MPa and 650 ℃ for 1h, carrying out constant-temperature hydrothermal treatment at 0.45MPa and 450 ℃ for 1h, reducing the pressure and the temperature, placing the sample in a nitric acid solution with the solid-to-liquid ratio of 1:11 and the concentration of 0.80mol/L, stirring at 60 ℃ for 1h, taking out, filtering, washing to be neutral, and drying at 100 ℃ for 24h to obtain the modified Y-Y type molecular sieve rich in medium-strong acid. The specific properties of the modified Y-Y molecular sieve are shown in Table 1.

Comparative example

Reacting NH₄Carrying out constant-temperature hydrothermal treatment on the Y-Y type molecular sieve at 550 ℃ under 0.15MPa for 3h, reducing the pressure and the temperature, placing a sample in a nitric acid solution with the solid-to-liquid ratio of 1:20 and the concentration of 1.0mol/L, stirring for 1h at 70 ℃, taking out, filtering, washing to be neutral, and drying for 24h at 100 ℃ to obtain the modified Y-Y type molecular sieve rich in medium and strong acid. The specific properties of the modified Y-Y molecular sieve are shown in Table 1.

The application of the molecular sieve in the hydrocracking catalyst comprises the following steps:

preparation method of hydrocracking catalyst 1: uniformly mixing the modified Y-Y type molecular sieve, amorphous silicon aluminum and alumina powder, adding an acid solution, fully rolling and forming, drying at 100 ℃ for 12 hours, taking out, and roasting at 600 ℃ for 8 hours to obtain a catalyst carrier; preparing W, Ni metal solution, and impregnating the catalyst carrier; or preparing a metal solution of Mo and Ni, soaking the catalyst carrier, drying at 100 ℃ for 12 hours, taking out, placing in a muffle furnace, setting the temperature at 500 ℃, and roasting for 6 hours to obtain the hydrocracking catalyst. The hydrocracking catalyst properties are as shown in table 2.

Preparation method 2 of hydrocracking catalyst: uniformly mixing modified Y-Y type molecular sieve powder, amorphous silicon aluminum, alumina powder, molybdenum oxide, tungsten oxide (or nickel oxide) and the like, adding an acid solution, fully rolling and forming, drying at 100 ℃ for 8 hours, taking out, placing in a muffle furnace, setting the temperature at 550 ℃, and roasting for 8 hours to obtain the hydrocracking catalyst. The hydrocracking catalyst properties are as shown in table 2.

Catalyst evaluation conditions: a200 m1 small hydrogenation apparatus was used as an evaluation apparatus, and the catalyst was presulfided before activity evaluation. The properties of the raw oil used for the evaluation are shown in Table 3, and the results of comparison of the reaction process conditions and the catalyst reaction performance are shown in Table 4. When the catalyst is evaluated, the raw oil directly enters a hydrocracking catalyst bed layer after passing through a hydrofining catalyst bed layer, and the organic nitrogen content in the raw oil is controlled to be lower than 10ppm when passing through the hydrofining catalyst bed layer.

TABLE 1 physicochemical Properties of modified Y-Y type molecular sieves

TABLE 2 composition of hydrocracking catalyst

TABLE 3 Properties of the raw materials

TABLE 4 Process conditions and catalyst reactivity

The hydrocracking reaction result shows that when the reaction conversion rate is controlled to be the same, the reaction temperature of the modified Y-Y type molecular sieve is 7-13 ℃ lower than that of the original Y-Y type molecular sieve, and the yield of heavy naphtha is improved by 2.3-4.0%. The result shows that the activity and the target product selectivity of the modified Y-Y type molecular sieve prepared by the method are superior to those of the original Y-Y type molecular sieve.