阅读说明：本技术 一种馏分油加氢裂化催化剂及其制备方法和应用 (Distillate oil hydrocracking catalyst, preparation method and application thereof ) 是由 杜艳泽 高杭 秦波 柳伟 张晓萍 于 2019-10-28 设计创作，主要内容包括：本发明公开一种馏分油加氢裂化催化剂及其制备方法和应用,所述催化剂中以最终催化剂的重量为基准,含有3～78%的改性Y-Y型分子筛,所述改性Y-Y型分子筛具有如下性质：SiO-2/Al-2O-3为5～55；比表面积为560～960m～2/g；酸量为0.9～1.650mmol/g。所述催化剂能够增加催化剂可接触的有效酸性位,为大分子反应过程提供更多空间,提高目标产物选择性。(The invention discloses a distillate oil hydrocracking catalyst, a preparation method and an application thereof, wherein the catalyst contains 3-78% of modified Y-Y type molecular sieve based on the weight of the final catalyst, and the modified Y-Y type molecular sieve has the following properties: SiO 2 2 /Al 2 O 3 5 to 55; the specific surface area is 560 to 960m 2 (ii)/g; the amount of acid is 0.9 to 1.650 mmol/g. The catalyst can increase the available acid sites which can be contacted by the catalyst, provide more space for a macromolecular reaction process, and improve the selectivity of a target product.)

1. A distillate oil hydrocracking catalyst is characterized in that: the catalyst contains 3-78% of modified Y-Y type molecular sieve based on the weight of the final catalyst, and the modified Y-Y type molecular sieve has the following properties: SiO 2₂/Al₂O₃5 to 55; the specific surface area is 560 to 960m²(ii)/g; the amount of acid is 0.9 to 1.650 mmol/g.

2. The catalyst of claim 1, wherein: the catalyst contains 10-65% of modified Y-Y type molecular sieve based on the weight of the final catalyst, and the modified Y-Y type molecular sieve has the following properties: SiO 2₂/Al₂O₃8 to 25; the specific surface area is 700-850 m²(ii)/g; the amount of acid is 1.15 to 1.470 mmol/g.

3. The catalyst of claim 1, wherein: the modified Y-Y type molecular sieve has the following properties: SiO 2₂/Al₂O₃Is 10 to 15; the amount of acid is 1.2 to 1.4 mmol/g.

4. The method of claim 1, wherein: the catalyst contains VIB active metals and/or VIII active metals, and the VIB active metals account for 5-35% of oxides based on the weight of the final catalyst; the amount of the group VIII active metal is 1-10% by weight of oxide.

5. The method of claim 4, wherein: based on the weight of the final catalyst, the VIB group active metal accounts for 10-28% of the oxide; the amount of the VIII group active metal is 3-8% in terms of oxide; the group VIII metal is cobalt and/or nickel and the group VIB metal is tungsten and/or molybdenum.

6. The method of claim 1, wherein: the catalyst further comprises alumina and/or amorphous silicon-aluminum by taking the weight of the final catalyst as a reference, wherein the content of the alumina and/or amorphous silicon-aluminum is 3-65%.

7. A process for the preparation of a catalyst according to any one of claims 1 to 6, characterized in that: the method comprises the following steps:

preparing a modified Y-Y type molecular sieve;

forming the material containing the modified Y-Y type molecular sieve prepared in the step (1) and active metal

And (2) treating, drying and roasting after molding to prepare a hydrocracking catalyst, or loading active metal after molding the modified Y-Y type molecular sieve prepared in the step (1) into a carrier, and drying and roasting to prepare the hydrocracking catalyst.

8. The method of claim 7, wherein: the preparation method of the modified Y-Y type molecular sieve in the step (1) comprises the following steps: adding deionized water into an HY-Y molecular sieve for dissolving, wherein the solid-liquid mass ratio is 1: 5-1: 40, heating to 40-98 ℃ under a stirring state, sequentially and slowly adding an aluminum source and a silicon source, keeping the temperature for 0.5-2.0 h, placing a filtered and dried product in a hydrothermal treatment device, and performing secondary crystallization at a certain temperature to obtain the modified Y-Y molecular sieve.

9. The method of claim 8, wherein: the HY-Y type molecular sieve has the following properties: SiO 2₂With Al₂O₃The molar ratio is 4.5-30.0, and the specific surface area is 630-880 m²/g；Na₂The mass fraction of O is 0.02 wt% -0.50 wt%.

10. The method of claim 8, wherein: the aluminum source is one or more of aluminum isopropoxide, aluminum ethoxide, aluminum triethoxide and aluminum n-butoxide, and the addition amount of the aluminum source is Al₂O₃Calculated as HY-Y type molecular sieve, is 0.05-5.0 wt%.

11. The method of claim 8, wherein: the silicon source is low-sodium silica sol, wherein the content of silicon dioxide is 5-35 wt%, the content of sodium oxide is 0.02-0.5 wt%, and the adding amount of the silicon source is SiO₂Calculated as 5.0-25.0 wt% of the final Y-Y type molecular sieve.

12. The method of claim 8, wherein: the second crystallization condition in the hydrothermal treatment device environment is that the hydrothermal crystallization is carried out for 0.5-24 h at the constant temperature of 100-750 ℃ under the pressure of 0.05-0.50 MPa.

13. The method of claim 8, wherein: the molding in the step (2) is spherical, strip-shaped or clover-shaped, and one or more of adhesive, extrusion aid or metal additive is added in the molding process.

14. The method of claim 8, wherein: the drying temperature in the step (2) is 100-120 ℃, the drying time is 8-24 hours, the roasting temperature is 450-600 ℃, and the roasting time is 2-8 hours.

15. A hydrocracking process characterized by: the catalyst prepared by the method of any one of claims 1 to 6, wherein the reaction process conditions are as follows: the reaction pressure is 5-20 MPa, the reaction temperature is 260-450 ℃, the hydrogen-oil ratio is 500-1800, and the volume space velocity is 0.5-5.0 h^-1。

Technical Field

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

Background

The Y-type molecular sieve is an excellent active component of the catalyst, is formed by mutually communicating octahedral zeolite cages along the directions of three crystal axes of xyz through twelve-membered rings, has high cracking activity and high selectivity, and is an indispensable part in a hydrocracking catalyst.

The framework silicon-aluminum ratio has a direct effect on the hydrothermal stability of the Y-type molecular sieve. The Y-type molecular sieve with the low silicon-aluminum ratio (3-4.2) has poor hydrothermal stability, and on the contrary, the Y-type molecular sieve with the high silicon-aluminum ratio (> 4.3) has good hydrothermal stability and acid stability, and can be used as a catalytic material to play a cracking role in the petroleum processing process after being modified.

In the hydrocracking field, the work of modified post-treatment of Y-type molecular sieves has been attracting much attention. At present, the modification treatment of the Y-type molecular sieve is mainly to realize desilication and dealumination of a molecular sieve framework by one or a combination of several methods of ion exchange, heat treatment, hydrothermal treatment, acid or acid salt treatment, alkali or alkaline salt and complex treatment and the like, thereby improving the stability of the molecular sieve framework and generating a large number of mesoporous structures. The common method is that after the Y-type molecular sieve is subjected to ion exchange, the Y-type molecular sieve is subjected to heat treatment or hydrothermal treatment, and further acid treatment is performed, so that the aim of removing framework aluminum is fulfilled, the hydrothermal stability is further improved, and a large number of secondary pore structures are generated. The generation of a large number of secondary holes is beneficial to the reaction and diffusion of macromolecules, and the utilization rate of the acid sites of the molecular sieve is effectively improved. In recent years, the method developed in the field is to perform alkali or alkaline salt treatment on the Y-shaped molecular sieve after acid or acid salt treatment, wherein the alkali treatment after acid treatment can greatly increase the secondary pores of the molecular sieve, improve the acid content of the molecular sieve and solve the problem of great reduction of the skeleton acid content of the molecular sieve caused by single deep acid treatment. The existing Y-type molecular sieve modification technology mainly focuses on the fact that a secondary pore structure is constructed by adjusting a pore structure of a molecular sieve, and then the diffusion performance of the molecular sieve is improved. However, in the actual reaction process, it is the acidic sites of the molecular sieve that have the cracking function.

CN109970076 introduces a modification method for coating a silicon-aluminum mesoporous layer on the surface of a Y-type molecular sieve, which enables a mesoporous structure to grow on and wrap the surface of the Y-type molecular sieve, and the pore structure is distributed in a gradient manner. CN106853973 discloses a preparation method of a strong acid type Y molecular sieve, which is to mix NaY molecular sieve with a carrierTreating in ammonium salt water solution and acid solution, and placing in a container containing cetyl trimethyl ammonium bromide, ammonia water and LaCl₃The strong acid type Y-shaped molecular sieve is obtained by modification and high-temperature roasting in the solution. CN102198950 discloses a method for preparing NaY molecular sieve with high silica-alumina ratio, two gels are prepared according to different molar ratios, mixed gel is obtained by respective crystallization, and the NaY molecular sieve with high silica-alumina ratio is synthesized in a short time. CN109967117 discloses a method for modifying a Y-type molecular sieve, which comprises performing a gelling reaction and a silicon source aging on a NaY molecular sieve filter cake, an aluminum source and an alkali solution, and placing the aged slurry in a closed reaction kettle for hydrothermal crystallization to obtain a modified Y-type molecular sieve with a surface attached with a wrinkled mesoporous structure.

The successful preparation of the Y-Y type isomorphous composite molecular sieve widens the utilization path of the Y type molecular sieve, and the corresponding series of modification technologies realize the great improvement of the performance of the Y-Y type isomorphous molecular sieve. Therefore, further improvement of modification technology to improve the acid site performance of the Y-Y type isomorphous molecular sieve is an important research direction.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a distillate oil hydrocracking catalyst, a preparation method and application thereof, wherein the hydrocracking catalyst contains a method of modifying a Y-Y type molecular sieve with high acid content, the effective acid sites which can be contacted by the catalyst can be increased, the hydrocracking catalyst provides more space for a macromolecular reaction process, and the selectivity of a target product is improved.

A distillate oil hydrocracking catalyst contains 3-78%, preferably 10-65% of modified Y-Y type molecular sieve based on the weight of the final catalyst, and the modified Y-Y type molecular sieve has the following properties: SiO 2₂/Al₂O₃5 to 55, preferably 8 to 25, and more preferably 10 to 15; the specific surface area is 560 to 960m²A concentration of 700 to 850m is preferred²(ii)/g; the amount of the acid is 0.9 to 1.650mmol/g, preferably 1.15 to 1.470mmol/g, and more preferably 1.2 to 1.4 mmol/g.

In the hydrocracking catalysis, the catalyst contains VIB group active metals and/or VIII group active metals, and based on the weight of the final catalyst, the VIB group active metals are 5-35%, preferably 10-28%, calculated by oxides; the amount of the VIII group active metal is 1-10% by weight, preferably 3-8% by weight of oxide; the group VIII metals are preferably cobalt (Co) and nickel (Ni), and the group VIB metals are preferably tungsten (W) and molybdenum (Mo).

In the hydrocracking catalyst, the catalyst further contains alumina and/or amorphous silicon-aluminum based on the weight of the final catalyst, and the content of the alumina and/or amorphous silicon-aluminum is 3-65%, preferably 5-50%.

A preparation method of a hydrocracking catalyst comprises the following steps:

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

(2) forming the material containing the modified Y-Y type molecular sieve prepared in the step (1) and active metal

And (2) treating, drying and roasting after molding to prepare a hydrocracking catalyst, or loading active metal after molding the modified Y-Y type molecular sieve prepared in the step (1) into a carrier, and drying and roasting to prepare the hydrocracking catalyst.

The preparation method of the modified Y-Y type molecular sieve in the step (1) comprises the following steps: adding deionized water into a hydrogen Y-Y type (HY-Y) molecular sieve for dissolving, wherein the solid-liquid mass ratio is 1: 5-1: 40, heating to 40-98 ℃ under a stirring state, sequentially and slowly adding an aluminum source and a silicon source, keeping the temperature for 0.5-2.0 h, placing the filtered and dried product in a hydrothermal treatment device, and performing secondary crystallization at a certain temperature to obtain the high-acid modified Y-Y type molecular sieve.

In the method, the HY-Y type molecular sieve is prepared by adopting the existing mature technology, and has the following properties: SiO 2₂With Al₂O₃The molar ratio is 4.5-30.0, and the specific surface area is 630-880 m²/g；Na₂The mass fraction of O is 0.02 wt% -0.50 wt%.

In the method, the aluminum source is easily hydrolyzed aluminum alkoxides such as aluminum isopropoxide, aluminum ethoxide, aluminum triethoxide, aluminum n-butoxide and the like, and the added amount is HY-Y type molecular sieve (Al is used)₂O₃Calculated by weight percent) of the total weight of the components is 0.05 to 5.0 wt percent.

In the method, the silicon source is low-sodium silica sol, wherein the content of silicon dioxide is 5-35 wt%, the content of sodium oxide is 0.02-0.5 wt%, and the adding amount of the silicon source is SiO₂Calculated as 5.0-25.0 wt% of the final Y-Y type molecular sieve.

In the method, the second crystallization condition in the hydrothermal treatment device environment is that the hydrothermal crystallization is carried out for 0.5-24 hours at a constant temperature of 100-750 ℃ under the pressure of 0.05-0.50 MPa.

In the method, the molding in the step (2) is spherical, strip-shaped or clover-shaped, and various additives such as non-adhesive, extrusion aid or metal additive can be added according to actual needs in the molding process.

In the method, the drying temperature in the step (2) is 100-120 ℃, the drying time is 8-24 hours, the roasting temperature is 450-600 ℃, and the roasting time is 2-8 hours.

In the invention, the acid amount of the catalyst is measured by the following method: the method adopts pyridine to measure the acid content of the sample by infrared. Heating at a speed of 10 ℃/min, desorbing for 0.5h after reaching 150 ℃, 250 ℃ and 350 ℃. The infrared spectrum is measured in the range of 4000cm^-1~400cm^-1Resolution of 2cm^-1. At 1400cm^-1 ~ 1700cm^-1The acid amount of the B acid and the L acid of the catalyst is calculated within the range.

A hydrocracking method carries out hydrogenation reaction under the action of the hydrocracking catalyst, and the process conditions are as follows: the reaction pressure is 5-20 MPa, the reaction temperature is 260-450 ℃, the hydrogen-oil ratio is 500-1800, and the volume space velocity is 0.5-5.0 h^-1。

The method adopts a hydrothermal steam secondary crystallization technology of a low-sodium system, and introduces the silicon-aluminum gel on the surface of the Y-Y type molecular sieve, so that the Y type molecular sieve with fully exposed acid sites is obtained by incomplete crystallization of the surface silicon-aluminum gel, the accessibility of the active sites of the Y-Y type molecular sieve is greatly improved, and the pore channel structure of the Y-Y type molecular sieve is unblocked. The modified Y-Y type molecular sieve obtained by the method can be directly used as an acidic carrier for preparing a hydrocracking catalyst. Compared with the prior art, the method disclosed by the invention combines the technical advantages of a conventional Y-type molecular sieve post-treatment method and a hydrothermal crystallization treatment technology. Under the condition that the silica-alumina ratio is the same, the adsorption capacity of the modified molecular sieve pyridine infrared acid is improved by 3-40%. The molecular sieve obtained by the method has high catalytic efficiency, is favorable for preferentially converting condensed ring macromolecules in the hydrocracking process, and has wide application prospect.

Drawings

FIG. 1 is an XRD diffractogram of the Y-Y type molecular sieve prepared in example 1.

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. In the following examples and comparative examples,% is mass% unless otherwise specified.

The hydrogen-type Y-Y molecular sieves used in the examples and comparative examples had the following properties: SiO 2₂With Al₂O₃Has a molar ratio of 6.9 and a specific surface area of 802 m²/g，Na₂The mass fraction of O is 0.22 wt%, and the preparation method comprises the following steps:

example 1

Dissolving HY-Y molecular sieve in water at solid-to-liquid ratio of 1:15, heating the solution to 80 deg.C under stirring, and slowly adding 0.6 wt% (based on Al)₂O₃Calculated as SiO) of aluminum ethoxide and 18.0 wt.% (calculated as SiO)₂Calculated) is stirred for 1.0 hour at constant temperature, after filtration and drying, the sample is hydrothermally crystallized for 8.0 hours at constant temperature under the pressure of 0.17MPa and the temperature of 280 ℃ to obtain the high-acid-content modified Y-Y type molecular sieve, and the specific properties of the obtained molecular sieve are shown in Table 1.

Example 2

Dissolving HY-Y molecular sieve in water at solid-to-liquid ratio of 1:8, heating the solution to 70 deg.C under stirring, and slowly adding 1.8 wt% (based on Al)₂O₃Calculated as SiO) of aluminum triethoxide and 19.0 wt.% (calculated as SiO)₂Calculated) for 1.5 hours, filtering and drying, and then carrying out hydrothermal crystallization on the sample at the constant temperature of 580 ℃ under the pressure of 0.22MPa for 3.0 hours to obtain the high-acid-content modified Y-Y type molecular sieve, wherein the specific properties of the obtained molecular sieve are shown in Table 1.

Example 3

Dissolving HY-Y molecular sieve in water at solid-to-liquid ratio of 1:32, heating to 55 deg.C under stirring, and slowly adding 3.4 wt% (based on Al)₂O₃Calculated as SiO) of aluminum isopropoxide and 25.0 wt.% (calculated as SiO)₂Calculated) is stirred for 2.0 hours at constant temperature, after filtration and drying, the sample is hydrothermally crystallized for 18 hours at constant temperature under the pressure of 0.32MPa and the temperature of 350 ℃ to obtain the high-acid-content modified Y-Y type molecular sieve, and the specific properties of the obtained molecular sieve are shown in Table 1.

Example 4

Dissolving HY-Y molecular sieve in water at solid-to-liquid ratio of 1:8, heating the solution to 60 deg.C under stirring, and slowly adding 2.6 wt% (based on Al)₂O₃Calculated as SiO) of aluminum sec-butoxide and 13.5% by weight₂Measured) for 1.5 hours, filtering and drying, and then carrying out hydrothermal crystallization on the sample at the constant temperature of 300 ℃ for 12 hours under the pressure of 0.18MPa to obtain the high-acid-content modified Y-Y type molecular sieve, wherein the specific properties of the obtained molecular sieve are shown in Table 1.

Example 5

Dissolving HY-Y molecular sieve in water at solid-to-liquid ratio of 1:15, heating to 65 deg.C under stirring, and slowly adding 0.13 wt% (based on Al)₂O₃Calculated as SiO) of aluminum n-butoxide and 17.0 wt.% (calculated as SiO)₂Measured) for 1.0 hour, filtering and drying, and then carrying out hydrothermal crystallization on the sample at the constant temperature of 250 ℃ for 18 hours under the pressure of 0.29MPa to obtain the high-acid-content modified Y-Y type molecular sieve, wherein the specific properties of the obtained molecular sieve are shown in Table 1.

The application of the high-acid-content modified Y-Y type molecular sieve in the hydrocracking catalyst comprises the following steps:

preparation method of hydrocracking catalyst 1: uniformly mixing the modified Y-type molecular sieve powder, amorphous silicon aluminum and alumina powder, continuously adding an acid solution, fully rolling and molding, and drying the prepared catalyst at 100 ℃ for 8 hours. Roasting the dried catalyst at 600 ℃ for 8h to obtain a catalyst carrier; preparing a metal impregnation solution of W and Ni or a metal impregnation solution of Mo and Ni, impregnating the catalyst carrier, drying at 120 ℃ for 6h, and roasting at 500 ℃ for 6h 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-type molecular sieve powder, alumina powder, amorphous silicon-aluminum, molybdenum oxide, tungsten oxide, nickel oxide and the like, continuously adding an acid solution, fully rolling and forming, placing the prepared catalyst at 100 ℃ for drying for 8h, and roasting the dried catalyst at 550 ℃ for 8h to obtain the hydrocracking catalyst. The hydrocracking catalyst properties are as shown in table 2.

Catalyst evaluation conditions: the evaluation device is a 200ml small hydrogenation device, and the catalyst needs to be presulfurized before being evaluated. The properties of the raw oil used for evaluating the catalyst activity are shown in Table 3, the reaction process conditions are shown in Table 4, and the results of the comparison of the catalyst reaction performances are shown in Table 5. When the catalyst is evaluated, raw oil firstly passes through a hydrofining catalyst bed layer, the organic nitrogen content in the raw oil is controlled to be lower than 10ppm, and then the raw oil directly enters a hydrocracking catalyst bed layer.

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

TABLE 2 composition of hydrocracking catalyst

TABLE 3 Process conditions

TABLE 4 Properties of the raw materials

TABLE 5 catalyst reactivity

The hydrocracking reaction result shows that the molecular sieve obtained by the method has the same conversion rate as an HY-Y type molecular sieve, the reaction temperature is 6-12 ℃ lower, and the BMCI value and the content of more than two-ring cyclane of a tail oil product are lower than those of a catalyst prepared by the HY-Y type molecular sieve. The molecular sieve modified by the method has better accessibility of the active sites and is beneficial to the hydrogenation ring-opening process of polycyclic aromatic hydrocarbon.