Ga-ZSM-5@silicate-1 complex, preparation method therefor, use thereof, hydrogenation catalyst, and hydro-upgrading method

Abstract

Disclosed in the present invention are a Ga-ZSM-5@Silicate-1 complex, a preparation method therefor, use thereof, a hydrogenation catalyst, and a hydro-upgrading method. The complex comprises a Ga-ZSM-5 heteroatom molecular sieve and a Silicate-1 layer covering the Ga-ZSM-5 heteroatom molecular sieve. The complex has a flaky morphology. The complex is particularly suitable for use as a hydrogenation component, especially as a cracking component of a diesel hydro-upgrading / hydrocracking catalyst; moreover, the preparation method for the complex is simple and easy to operate.

Description

Ga-ZSM-5@Silicate-1 composite, its preparation method and application, hydrogenation catalyst and hydrogenation modification method

[0001] Cross-references to related applications

[0002] This application claims the benefit of Chinese Patent Application No. 2025102126021, filed on February 25, 2025, and Chinese Patent Application No. 2025102126017, filed on February 25, 2025, the contents of which are incorporated herein by reference. Technical Field

[0003] This invention belongs to the field of molecular sieve synthesis technology, specifically relating to a Ga-ZSM-5@Silicate-1 complex, its preparation method and application, as well as a hydrogenation catalyst and a hydrogenation modification method. Background Technology

[0004] ZSM-5 molecular sieves are widely used in petrochemicals, adsorption separation, and other fields due to their unique pore structure and acidic characteristics. ZSM-5 molecular sieves belong to the MFI topology, orthorhombic crystal system, and their pores are their cavities. The framework structure contains two types of perpendicularly intersecting ten-membered ring channels: straight pores with elliptical ten-membered rings (major axis 0.58 nm, minor axis 0.52 nm) and near-circular "Z"-shaped pores with a diameter of 0.54 nm. The intersection of these two types of channels has a dimension of 0.9 nm, where the strong acid sites and catalytic active sites of ZSM-5 are typically concentrated. In recent years, short b-axis ZSM-5 plate-like molecular sieves have emerged as a type of molecular sieve with high hydrothermal stability and good shape selectivity, exhibiting a regular micropore structure, large specific surface area, numerous exposed active sites, and fast mass transfer rate.

[0005] CN117263204A discloses a sheet-like ZSM-5 molecular sieve, its preparation method, and its application, specifically relating to the field of catalyst preparation technology. The method for preparing the sheet-like ZSM-5 molecular sieve involves gelling and aging a seed solution, followed by etching the crystal nuclei with hydrogen fluoride at a temperature below 20°C. After obtaining the molecular sieve precursor, it is further aged before adding an aluminum source to generate catalytically active sites, and then crystallizing at a temperature below 110°C, reducing the thickness of the sheet-like ZSM-5 molecular sieve to a minimum of 16.4 nm.

[0006] CN112691697A reports a syngas conversion coupled catalyst and its applications, particularly relating to a process for converting syngas to produce aromatics and / or light hydrocarbons, and the catalyst used. The catalyst system possesses catalytic activity for syngas conversion and the synthesis of aromatics and / or light hydrocarbons. The syngas conversion activity is provided by a metal oxide, while the aromatics and / or light hydrocarbon synthesis activity is provided by a plate-like ZSM-5 molecular sieve. The plate-like ZSM-5 molecular sieve is a hexagonal prism sheet with a c-axis to b-axis ratio of (2:1)–(50:1) and an a-axis to b-axis ratio of (3:1)–(20:1). Under the action of this coupled catalyst, syngas can be efficiently converted to aromatics and / or light hydrocarbons, especially with high selectivity for C6-C8 aromatic products.

[0007] CN117566753A discloses a synthesis process for b-axis oriented sheet-like ZSM-5 molecular sieves with high hydrothermal stability: a) dissolving a structure-directing agent, an aluminum source, and a mineralizer in water and stirring until completely dissolved; b) adding a silicon source to step a and stirring until completely hydrolyzed; c) adding seed crystals to the solution from step b, then transferring it to a high-pressure hydrothermal reactor for hydrothermal crystallization, and filtering, washing, drying, and calcining the resulting solid to obtain a sheet-like ZSM-5 molecular sieve with high hydrothermal stability.

[0008] CN113184875A discloses a method for preparing an all-silica short b-axis ZSM-5 zeolite molecular sieve, comprising the following steps: (1) Preparing a reaction solution: adding tetraethyl orthosilicate dropwise to an ultrapure water mixture of sodium hydroxide, tetrapropylammonium hydroxide, isopropanol and urea, and stirring thoroughly; (2) Homogeneous reaction: subjecting the reaction solution stirred in step (1) to a homogeneous reaction; (3) washing the solution after the reaction in step (2) and drying the precipitate; (4) Calcination: taking the dried product from step (3) and calcining it to obtain the all-silica short b-axis ZSM-5 zeolite molecular sieve.

[0009] Currently, existing technologies typically add crystal growth inhibitors to the mother liquor during the synthesis of short b-axis plate-shaped ZSM-5 molecular sieves. However, the presence of these inhibitors often restricts the entry of Al elements into the molecular sieve framework. Furthermore, the low acidity of the molecular sieve due to an excessively high silica-to-alumina ratio limits its application in acid catalytic reactions. In particular, current technologies often use ZSM-5 molecular sieves as the cracking component in diesel hydrodewaxing catalysts. The plate-like morphology of short b-axis ZSM-5 molecular sieves can effectively improve the mass transfer and catalytic reaction of large hydrocarbon molecules in diesel feedstocks. However, on the one hand, the low total acidity of short b-axis plate-shaped ZSM-5 molecular sieves reduces their catalytic efficiency; on the other hand, the high acidity ratio on the molecular sieve surface can easily lead to excessive cracking of hydrocarbon molecules in diesel, reducing the yield of the target component in low-pour-point diesel. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention provides a Ga-ZSM-5@Silicate-1 composite, its preparation method, applications, hydrogenation catalyst, and hydrotreating method. The Ga-ZSM-5@Silicate-1 composite exhibits a plate-like morphology, overcoming the defect of high acid content on the surface of plate-like ZSM-5 molecular sieves, significantly improving the application prospects of ZSM-5 molecular sieves. This Ga-ZSM-5@Silicate-1 composite is particularly suitable as a component of hydrogenation catalysts, especially as a cracking component in diesel hydrotreating and hydrocracking catalysts. Furthermore, the preparation method of the Ga-ZSM-5@Silicate-1 composite is simple and easy to operate.

[0011] The first aspect of the present invention provides a Ga-ZSM-5@Silicate-1 composite, the composite comprising: a Ga-ZSM-5 heteroatom molecular sieve and a Silicate-1 layer coating the Ga-ZSM-5 heteroatom molecular sieve, the composite having a plate-like morphology.

[0012] A second aspect of the present invention provides a method for preparing a Ga-ZSM-5@Silicate-1 composite, wherein the method includes:

[0013] (1) The sheet-like ZSM-5 molecular sieve was treated with a mixed solution of ammonium fluorosilicate and Ga precursor, and the resulting solid was dried and calcined to obtain Ga-ZSM-5 heteroatom molecular sieve;

[0014] (2) The Ga-ZSM-5 heteroatom molecular sieve obtained in step (1) is mixed with silicon source, template agent and water to obtain crystallization solution, and then crystallization is carried out; the obtained solid is dried and calcined.

[0015] A third aspect of the present invention provides a Ga-ZSM-5@Silicate-1 composite prepared by the method of the present invention.

[0016] The fourth aspect of this invention provides the application of the Ga-ZSM-5@Silicate-1 composite described herein in hydrogenation catalysts.

[0017] The fifth aspect of the present invention provides a hydrogenation catalyst, the hydrogenation catalyst containing the Ga-ZSM-5@Silicate-1 complex of the present invention and a hydrogenation-active metal oxide, preferably, the content of the Ga-ZSM-5@Silicate-1 complex is 40wt%-70wt%, more preferably 50wt%-60wt%, based on the total weight of the catalyst.

[0018] The sixth aspect of the present invention provides a hydrorefining method using the hydrorefining catalyst described in the present invention. The method includes: (a) a diesel feedstock is mixed with hydrogen and then enters a hydrorefining reaction zone to react with a hydrorefining catalyst bed.

[0019] (b) The hydrorefined product oil and gaseous products are introduced into the hydrocracking reaction zone and react with the hydrocracking catalyst bed. The effluent from the hydrocracking reaction is separated into gas, naphtha and low-pour-point diesel by gas-liquid separation and fractionation.

[0020] Compared with the prior art, the composite, its preparation method, and its application provided by the present invention have the following beneficial effects:

[0021] 1. The plate-like morphology of the complex of the present invention is conducive to the mass transfer and reaction process of macromolecular reactants; the acidity characteristics of the complex can be flexibly controlled.

[0022] 2. This invention first utilizes isomorphous substitution to dope Ga heteroatoms into the plate-like ZSM-5 molecular sieve and modify it with ammonium fluorosilicate. This effectively increases the number of acidic active sites in the plate-like ZSM-5 molecular sieve while effectively reducing the surface acid content. Compared with modification using ammonium fluorosilicate alone, this invention effectively increases the total acid content and reduces the surface acid ratio, effectively solving the defect of high surface acid content in plate-like ZSM-5 molecular sieves and significantly improving the application prospects of ZSM-5 molecular sieves. Then, the Ga-ZSM-5 heteroatom molecular sieve is coated with pure silicon Silicate-1 molecular sieve using crystal epitaxial growth, which can effectively reduce the surface acid active sites while ensuring the shape-selective pore structure of the molecular sieve.

[0023] 3. The Ga-ZSM-5@Silicate-1 composite obtained in this invention is used as a cracking component in a diesel hydrodewaxing catalyst. The composite has a complete surface pore structure and low acidity, which is conducive to the mild cracking and efficient isomerization of low pour point straight-chain alkane components in diesel feedstock, effectively improving the yield of low pour point diesel and reducing the pour point of diesel. Attached Figure Description

[0024] Figure 1 is a SEM image of the Ga-ZSM-5 molecular sieve in Example 1 of the present invention;

[0025] Figure 2 shows the Ga-ZSM-5 molecular sieve in Example 1 of this invention. 71 NMR spectrum;

[0026] Figure 3 is a SEM image of the Ga-ZSM-5@Silicate-1 composite synthesized in Example 1 of the present invention;

[0027] Figure 4 is a TEM image of the Ga-ZSM-5@Silicate-1 composite synthesized in Example 1 of this invention;

[0028] Figure 5 shows the XRD pattern of the Ga-ZSM-5@Silicate-1 composite synthesized in Example 1 of this invention;

[0029] Figure 6 is a SEM image of the conventional ZSM-5 molecular sieve in Comparative Example 4 of the present invention;

[0030] Figure 7 is a SEM image of the Ga-ZSM-5@Silicate-1 composite synthesized in Comparative Example 4 of the present invention. Detailed Implementation

[0031] The present invention provides a Ga-ZSM-5@Silicate-1 composite, which comprises: a Ga-ZSM-5 heteroatom molecular sieve and a Silicate-1 layer coating the Ga-ZSM-5 heteroatom molecular sieve, and the composite has a plate-like morphology.

[0032] The complex of the present invention has good acid distribution characteristics and is particularly suitable for hydrogenation modification and dewaxing.

[0033] According to a preferred embodiment of the present invention, the surface acid content of the composite is 2.0%-4.2%, and the surface acid content is calculated as surface acid content / total acid content × 100%. The total acid content is characterized by pyridine infrared spectroscopy, and the surface acid content is characterized by di-tert-butylpyridine infrared spectroscopy. In contrast, the surface acid content of conventional Ga-modified ZSM-5 heteroatom molecular sieves is 10%-25%, and the surface acid content of ZSM-5 molecular sieves modified with fluorosilicone alone is 5%-10%.

[0034] Complexes with the aforementioned surface acid content have the advantage of reducing excessive alkane cracking. There are no special requirements for the specific surface acid content and total acid content. The following is an illustrative description, but it does not limit the scope of the invention.

[0035] According to a preferred embodiment of the present invention, the total acidity (pyridine infrared acidity) of the complex is 0.1 mmol / g-0.5 mmol / g, preferably 0.2 mmol / g-0.4 mmol / g.

[0036] According to a preferred embodiment of the present invention, the surface acidity (di-tert-butylpyridine infrared acidity) of the complex is 0.002 mmol / g-0.02 mmol / g, preferably 0.005-0.015 mmol / g.

[0037] In this invention, the Ga-ZSM-5@Silicate-1 composite is presented as a hexagonal prism sheet.

[0038] The composite of the present invention has an excellent crystal plane size distribution. According to a preferred embodiment of the present invention, the b-axis dimension perpendicular to the (010) crystal plane is 30 nm-200 nm, preferably 60-160 nm; the ratio of the a-axis dimension perpendicular to the (100) crystal plane to the b-axis dimension is (1:1)-(5:1), preferably (1.2:1)-(2.5:1); and the ratio of the c-axis dimension parallel to the (010) and (100) crystal planes to the b-axis dimension is (5:1)-(15:1), preferably (5:1)-(8:1). The crystal morphology and size of the composite are characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

[0039] In the composite of the present invention, the specific surface area of ​​the composite is 250 m². 2 / g-500m 2 / g, preferably 300m 2 / g-450m 2 / g.

[0040] In the composite of the present invention, the total pore volume of the composite is 0.15 cm³. 3 / g-0.3cm 3 / g, preferably 0.2cm 3 / g-0.25cm 3 / g.

[0041] In the composite of the present invention, the mesoporous pore volume accounts for 10%-30%, preferably 15%-25%.

[0042] In the composite of the present invention, the silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the composite is 100-300, preferably 120-200.

[0043] In the composite of the present invention, the Ga content can be selected within a wide range. According to a preferred embodiment of the present invention, the Ga heteroatom content (in terms of oxide mass fraction) is ≤3.0% by weight, preferably ≤2.0%, and more preferably 0.3-1.5%.

[0044] In the composite of this invention, the coordination mode of Ga atoms in the molecular sieve framework adopts Ga... 71 Solid-state NMR characterization was used for analysis.

[0045] In the complex of the present invention, the Na content can be selected within a wide range. According to a preferred embodiment of the present invention, the Na2O mass content is ≤0.3%, preferably ≤0.1%.

[0046] In the composite of the present invention, the composite has typical MFI topological diffraction peaks and a relative crystallinity of 100%-120%, preferably 105%-115%.

[0047] In the composite of the present invention, the average thickness of the Silicate-1 layer in the composite is determined by characterizing the difference between the composite size and the core phase molecular sieve size using SEM and TEM. The average thickness of the Silicate-1 layer is 5nm-50nm, preferably 20nm-30nm.

[0048] A second aspect of this invention is to provide a method for preparing a Ga-ZSM-5@Silicate-1 composite, the method comprising:

[0049] (1) The sheet-like ZSM-5 molecular sieve was treated with a mixed solution of ammonium fluorosilicate and Ga precursor, and the resulting solid was dried and calcined to obtain Ga-ZSM-5 heteroatom molecular sieve;

[0050] (2) The Ga-ZSM-5 heteroatom molecular sieve obtained in step (1) is mixed with silicon source, template agent and water to obtain crystallization solution, and then crystallization is carried out; the obtained solid is dried and calcined.

[0051] In the composite preparation method of the present invention, the contact treatment conditions of the mixed solution of the sheet-like ZSM-5 molecular sieve with ammonium fluorosilicate and heteroatom precursor in step (1) have a wide range of options. The preferred temperature is 60℃-120℃, and the preferred temperature is 80℃-100℃. The treatment time has a wide range of options and is specifically selected and determined according to the temperature. The preferred time is 3h-5h.

[0052] In this invention, the concentrations of each substance in the mixed solution can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of this invention.

[0053] This invention has found that excessively high ammonium fluorosilicate concentration and excessively low Ga concentration will cause severe dealuminization of the molecular sieve and low Ga atom doping amount, resulting in excessively low acid content in the obtained heteroatom molecular sieve; while excessively low ammonium fluorosilicate concentration and excessively high Ga concentration will cause insufficient dealuminization and Ga atoms cannot be fully doped into the molecular sieve framework.

[0054] According to a preferred embodiment of the present invention, the concentration of ammonium fluorosilicate in the mixed solution is 0.01 mol / L to 0.05 mol / L.

[0055] According to a preferred embodiment of the present invention, the concentration of Ga precursor in the mixed solution is 0.01 mol / L to 0.05 mol / L.

[0056] In the preparation method of the composite of the present invention, the amount of sheet-like ZSM-5 molecular sieve and mixed solution in step (1) can be selected from a wide range, and the preferred solid-liquid ratio is 1:20-50 (g:mL).

[0057] According to a preferred embodiment of the present invention, step (1) is performed at 60℃-120℃, preferably 80℃-100℃ for 3h-5h, and then the solid particles are filtered, washed, dried and calcined to obtain Ga-ZSM-5 heteroatom molecular sieve.

[0058] In the composite preparation method of the present invention, in step (1), solid-liquid separation is performed by filtration, and the product is washed with water until neutral before drying.

[0059] In this invention, there are no special requirements for the drying and calcination conditions in step (1). The following is an illustrative description, but it does not limit the scope of the invention.

[0060] According to one embodiment of the present invention, in step (1), the drying temperature is 80℃-120℃ and the drying time is 12h-24h.

[0061] According to one embodiment of the present invention, in step (1), the calcination atmosphere is air, the calcination temperature is 400℃-500℃, and the calcination time is 2h-4h.

[0062] In the composite preparation method of the present invention, the sheet-like ZSM-5 molecular sieve in step (1) can be prepared according to existing publicly available technology or by using commercially available products.

[0063] In the composite preparation method of the present invention, the specific surface area of ​​the sheet-like ZSM-5 molecular sieve in step (1) is 300 m². 2 / g-500m 2 / g, preferably 350m 2 / g-450m 2 / g; Total pore volume is 0.15cm³ 3 / g-0.3cm 3 / g, preferably 0.2cm 3 / g-0.25cm 3 / g; mesoporous pore volume percentage 5%-20%, preferably 10%-15%.

[0064] In the composite preparation method of the present invention, the b-axis dimension perpendicular to the (010) crystal plane in the sheet-like ZSM-5 molecular sieve in step (1) is 20nm-150nm, preferably 50-100nm; the ratio of the a-axis dimension perpendicular to the (100) crystal plane to the b-axis dimension is (2:1)-(5:1), and the ratio of the c-axis dimension parallel to the (010) crystal plane and (100) to the b-axis dimension is (6:1)-(15:1).

[0065] In the composite preparation method of the present invention, the silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) of the sheet-like ZSM-5 molecular sieve in step (1) is 80-250, preferably 100-150.

[0066] In the composite preparation method of the present invention, the sheet-like ZSM-5 molecular sieve in step (1) has a Na2O content of ≤0.3% by weight, preferably ≤0.1%.

[0067] In the preparation method of the composite of the present invention, the pyridine infrared acid content (total acid content) of the sheet-like ZSM-5 molecular sieve in step (1) is 0.05 mmol / g-0.4 mmol / g, preferably 0.1 mmol / g-0.3 mmol / g; the di-tert-butylpyridine infrared acid content (surface acid content) is 0.01 mmol / g-0.04 mmol / g, preferably 0.02-0.03 mmol / g; and the surface acid content is 10%-20%.

[0068] In this invention, the Ga precursor has no special requirements and can be an organic compound and / or an inorganic compound, such as a Ga salt, specifically at least one of gallium chloride and gallium nitrate.

[0069] In the composite preparation method of this invention, the Ga-ZSM-5 heteroatom molecular sieve obtained in step (1) has a specific surface area of ​​250 m². 2 / g-450m 2 / g, preferably 300m 2 / g-400m 2 / g; Total pore volume is 0.18cm³ 3 / g-0.35cm 3 / g, preferably 0.22cm 3 / g-0.28cm 3 / g, with a mesoporous pore volume ratio of 15%-40%, preferably 20%-30%.

[0070] In the composite preparation method of the present invention, the silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the Ga-ZSM-5 heteroatom molecular sieve obtained in step (1) is 90-280, preferably 100-180; the Ga heteroatom content (in terms of oxide mass fraction) is ≤3.5% by weight, preferably ≤2.5%, and more preferably 0.5-1.8%; the Na2O mass content is ≤0.3%, preferably ≤0.1%.

[0071] In the composite preparation method of the present invention, all Ga atoms in the Ga-ZSM-5 heteroatom molecular sieve obtained in step (1) are doped into the molecular sieve framework, and there are no non-framework Ga atoms.

[0072] In the composite preparation method of the present invention, the Ga-ZSM-5 heteroatom molecular sieve obtained in step (1) has typical MFI topological diffraction peaks and a relative crystallinity of 95%-115%, preferably 100%-110%.

[0073] In the composite preparation method of the present invention, the total acid content of the Ga-ZSM-5 heteroatom molecular sieve obtained in step (1) is 0.15 mmol / g-0.55 mmol / g, preferably 0.25 mmol / g-0.45 mmol / g; the surface acid content of the heteroatom molecular sieve is 0.005 mmol / g-0.03 mmol / g, preferably 0.01-0.02 mmol / g; and the surface acid content is 3.3%-5.5%.

[0074] In the composite preparation method of the present invention, in step (2), the silicon source in the crystallization solution is SiO2, and the ratio of SiO2:template:H2O is 1:(0.6-1.5):(500-1000), preferably SiO2:template:H2O is 1:(0.8-1.2):(600-800). The source of SiO2 in the present invention includes silicon composition of various raw materials such as ZSM-5 molecular sieve and ammonium fluorosilicate.

[0075] In this invention, the mass ratio of Ga-ZSM-5 heteroatom molecular sieve to silicon source (based on SiO2 content) in the mother liquor is 50-150:1, preferably 80-120:1.

[0076] In the composite preparation method of the present invention, the silicon source in step (2) has a wide range of options, and can be an organosilicone grease and / or an inorganic silicon source, preferably an organosilicone grease, wherein the organosilicone grease can be at least one of tetraethyl orthosilicate and methyl orthosilicate, and more preferably tetraethyl orthosilicate.

[0077] In this invention, the range of template agents that can be selected is relatively wide, and commonly used template agents can all be used in this invention. According to a preferred embodiment of this invention, the template agent is at least one of tetrapropylammonium hydroxide and tetrapropylammonium bromide.

[0078] In the composite preparation method of the present invention, the crystallization conditions in step (2) have a wide range of options. The following is an illustrative description, but it does not limit the scope of the present invention. For example, the crystallization temperature is generally 160℃-190℃, preferably 170℃-180℃, and the crystallization time is selected and adjusted according to the crystallization temperature. For example, the crystallization time is generally 6h-24h, preferably 12h-18h.

[0079] In the composite preparation method of the present invention, in step (2), solid-liquid separation is performed by filtration, and the product is washed with water until neutral before drying.

[0080] In this invention, there are no special requirements for the drying and calcination conditions in step (2). The following is an illustrative description, but it does not limit the scope of the invention.

[0081] According to a preferred embodiment of the present invention, the drying temperature is 80-120°C and the drying time is 12-24 hours.

[0082] According to a preferred embodiment of the present invention, the calcination temperature is 500-600℃ and the calcination time is 2-6h.

[0083] This invention provides a composite obtained by the method described in this invention. The molecular sieve prepared according to the method of this invention has the characteristics of the aforementioned molecular sieve, with a moderate acid content distribution, and is particularly suitable for use in hydrogenation catalysts, especially for hydrotreating and dewaxing. Accordingly, this invention provides the application of the composite described in this invention in hydrogenation catalysts; preferably, the hydrogenation catalyst is selected from one or more of diesel hydrotreating and hydrocracking catalysts, catalytic cracking catalysts, and MTO catalysts.

[0084] The composite prepared by the above method can be used as a cracking component of a diesel hydrocracking catalyst.

[0085] The present invention provides a hydrogenation catalyst containing the Ga-ZSM-5@Silicate-1 complex and a hydrogenation-active metal oxide as described in the present invention. Preferably, the content of the Ga-ZSM-5@Silicate-1 complex is 40wt%-70wt%, more preferably 50wt%-60wt%, based on the total weight of the catalyst.

[0086] According to one embodiment of the present invention, a hydrogenation catalyst is provided, wherein the hydrogenation catalyst contains 40%-70%, preferably 50%-60% of a Ga-ZSM-5@Silicate-1 complex based on its weight.

[0087] The amount of each component in the hydrogenation catalyst of the present invention can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of the present invention.

[0088] In this invention, the hydrogenation catalyst optionally contains a binder. Preferably, it contains 10%-40%, more preferably 20%-30% binder by weight of the total catalyst. The range of selectable binders is wide, and various commonly used binders can be used in this invention. For example, the binder is γ-alumina.

[0089] According to a preferred embodiment of the present invention, the catalyst contains 12wt%-20wt%, preferably 14wt%-17wt% hydrogenation active metal oxides based on the total weight of the catalyst.

[0090] In this invention, the types and contents of the hydrogenation active metals can be selected from a wide range. Various types and compositions of active metals used in hydrogenation can be used in this invention. The following is an illustrative description, but it does not limit the scope of this invention.

[0091] According to a preferred embodiment of the present invention, the hydrogenation catalyst contains 12%-20%, preferably 14%-17% hydrogenation active metal (calculated as metal oxide), based on the total weight of the catalyst.

[0092] In the hydrogenation catalyst of the present invention, the hydrogenation active metal is selected, for example, from metals of Group VIII and / or Group VIB.

[0093] According to a preferred embodiment of the present invention, the Group VIII metal is Ni and / or Co, with Ni being more preferred.

[0094] According to a preferred embodiment of the invention, the Group VIB metal is, for example, W and / or Mo, and more preferably W.

[0095] According to a preferred embodiment of the present invention, the hydrogenation active metal contains metals of Group VIII and Group VIB. More preferably, the mass content of Group VIII metal oxides is 2%-5% and the mass content of Group VIB metal oxides is 10%-15% based on the total weight of the catalyst.

[0096] According to a preferred embodiment of the present invention, in the catalyst, the composition of Ga-ZSM-5@Silicate-1 complex: γ-alumina: hydrogenated metal (based on oxides) is 40%-70%: 10%-40%: 12%-20%.

[0097] In the hydrogenation catalyst of this invention, the specific surface area of ​​the hydrogenation catalyst is 200 m². 2 / g-400m 2 / g, preferably 250m 2 / g-360m 2 / g, pore volume 0.2cm 3 / g-0.5cm 3 / g, preferably 0.25cm 3 / g-0.35cm 3 / g.

[0098] Hydrogenation catalysts containing the composition of this invention can achieve the objectives of this invention. There are no special requirements for their preparation methods; they can be prepared using conventional methods. The following is an illustrative description, but it does not limit the scope of this invention.

[0099] According to one embodiment of the present invention, the preparation method of the hydrogenation catalyst includes mixing Ga-ZSM-5@Silicate-1 composite, (binder such as γ-alumina) and hydrogenation active metal to obtain the hydrogenation catalyst, or first molding Ga-ZSM-5@Silicate-1 composite, (binder such as γ-alumina) and then loading hydrogenation active metal to obtain the hydrogenation modified catalyst.

[0100] The method of the present invention, a non-limiting method for preparing a hydrogenation catalyst, includes the following:

[0101] I) The Ga-ZSM-5@Silicate-1 composite and (binder such as γ-alumina) are mixed in a target ratio, and then a colloid (e.g., nitric acid solution) is added to the mixture to form a slurry. The slurry is then kneaded, shaped, dried, and calcined to obtain the hydrogenation catalyst support.

[0102] II) Impregnate the catalyst support obtained in step I) with an aqueous solution of a compound containing a hydrogenation active metal component, and then dry and calcine the impregnated support to obtain the hydrogenation catalyst.

[0103] In the hydrogenation catalyst preparation method of the present invention, in step I), the mass fraction ratio of Ga-ZSM-5@Silicate-1 composite and (binder such as γ-alumina) in the solid mixture is 45%-88%:12%-55%; the adhesive solvent is preferably a nitric acid solution with a concentration of 5-30% by mass; the solid content of the slurry is suitable for molding to obtain the product, preferably, the solid content of the slurry is, for example, 30-60% by mass.

[0104] In the hydrogenation catalyst preparation method of the present invention, the type of binder used in step I) is selected according to needs. For example, γ-alumina can be used, preferably with a specific surface area of ​​200 m². 2 / g-600m 2 / g, preferably 300m 2 / g-500m 2 / g; pore volume 0.5cm 3 / g-1.5cm 3 / g, preferably 0.8cm 3 / g-1.2cm 3 / g.

[0105] In the hydrogenation catalyst preparation method of the present invention, the shaped product in step I) is dried at 100℃-120℃ for 6h-12h, and then calcined at 500℃-600℃ for 1h-5h.

[0106] In the hydrogenation catalyst preparation method of the present invention, the compound containing the hydrogenation active metal component in step II) is a compound containing a Group VIII metal element and a compound containing a Group VIB metal element; the compound containing a Group VIII metal is selected from at least one of nickel and cobalt nitrates, chlorides, sulfates, formates, acetates, phosphates, citrates, oxalates, carbonates, basic carbonates, and hydroxides, preferably at least one of nickel nitrate, nickel sulfate, basic nickel carbonate, nickel chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, basic cobalt carbonate, and cobalt chloride; the compound containing a Group VIB metal is selected from at least one of molybdic acid, secondary molybdic acid, molybdate, secondary molybdate, tungstic acid, metatungstic acid, ethyl metatungstic acid, tungstate, metatungstate, and ethyl metatungstate, preferably at least one of ammonium molybdate and ammonium metatungstate.

[0107] In the hydrogenation catalyst preparation method of the present invention, in step II), the active metal is loaded onto the support obtained in step I) by liquid phase equal volume impregnation method.

[0108] In the hydrogenation catalyst preparation method of the present invention, the impregnation temperature in step II) is 5℃-90℃, preferably 30℃-60℃; the impregnation time is 1h-12h, preferably 3h-6h.

[0109] In the preparation method of the hydrogenation catalyst of the present invention, the support after impregnation with metal in step II) is dried at 100℃-120℃ for 6h-12h, and then calcined at 400℃-500℃ for 1h-3h.

[0110] This invention provides a hydrotreating method, characterized in that the method includes: (a) diesel feedstock is mixed with hydrogen and then enters a hydrorefining reaction zone to react with a hydrorefining catalyst bed;

[0111] (b) The hydrorefined product oil and gaseous products are introduced into the hydrocracking reaction zone and react with the hydrocracking catalyst bed. The effluent from the hydrocracking reaction is separated into gas, naphtha and low-pour-point diesel by gas-liquid separation and fractionation.

[0112] In this invention, step (a) is a conventional operation. The specific hydrorefining conditions and hydrorefining catalyst (the hydrorefining catalyst can be any type of commercial catalyst in the prior art, or it can be prepared according to common knowledge in the field as needed, as long as it can achieve the purpose of hydrorefining diesel feedstock in step (a)) can all be carried out by existing means. According to a preferred embodiment of the present invention, the hydrorefined product oil obtained after step (a) preferably has the following characteristics: nitrogen content <10ppm, preferably <5ppm; sulfur content <200ppm, preferably <100ppm; thereby enabling good subsequent hydrocracking reaction.

[0113] The method of the present invention can be applied to various diesel fuels, and preferably, the diesel fuels have the following properties:

[0114] For example, the density (at 20℃) of diesel fuel ranges from 0.80 g / cm³. 3 -0.90g / cm 3 The preferred value is 0.82 g / cm³. 3 -0.86g / cm 3 .

[0115] For example, the distillation range of diesel fuel is 150℃-380℃, preferably 180℃-370℃; the sulfur content is 0.1%-2.0%, preferably 0.8%-1.5%.

[0116] For example, the nitrogen content of diesel fuel is 10ppm-500ppm, preferably 50ppm-200ppm.

[0117] For example, the pour point of diesel fuel is -10℃ to 25℃, preferably -5℃ to 10℃.

[0118] In this invention, the conditions of the hydrocracking reaction zone in step (b) can be selected from a wide range. Various conventional reaction conditions in the art can be used for hydrocracking with the hydrocracking catalyst of this invention. The following is an illustrative description, but it does not limit the scope of this invention.

[0119] According to a preferred embodiment of the present invention, the reaction pressure of hydrocracking is 3MPa-10MPa, preferably 4MPa-8MPa.

[0120] The reaction temperature for hydrocracking is 300℃-400℃, preferably 320℃-370℃.

[0121] The volume hourly space velocity (VHSV) of the hydrocracking catalyst is 0.5 h⁻¹. -1 -3.0h -1 1.0h is preferred -1 -1.5h -1 .

[0122] The hydrogen-to-oil volume ratio in hydrocracking is 300-1000, preferably 500-800.

[0123] In this invention, the hydrocracking products obtained in step (b) are subjected to gas-liquid separation and fractionation to obtain gas, naphtha, and low-pour-point diesel. The yield of low-pour-point diesel is >85%, preferably >90%, and the yield is calculated as: (low-pour-point diesel mass / diesel feedstock mass) × 100%. The pour point of the low-pour-point diesel is <-40℃, preferably <-45℃, and is determined by a fully automatic pour point tester.

[0124] The present invention will be further described in detail below with reference to specific embodiments. The embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments. In the context of the present invention, unless otherwise specified, % refers to mass percentage content.

[0125] Unless otherwise specified, the experimental methods used in the following examples are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following examples were purchased from conventional biochemical reagent stores.

[0126] In this invention, the morphology and size of the molecular sieve were analyzed by SEM / TEM characterization; the crystal structure and relative crystallinity of the molecular sieve were determined by XRD characterization; the average particle size of the molecular sieve was determined by a laser particle size analyzer; the elemental composition of the molecular sieve was determined by XRF characterization; and the pore information was obtained by nitrogen adsorption-desorption testing of the molecular sieve at 77K using an ASAP 2420 automatic physical adsorption instrument. The acidity characteristics of the molecular sieve were determined by pyridine adsorption infrared spectroscopy; the elemental composition of the molecular sieve and catalyst was determined by XRF characterization; the doping morphology of heteroatoms in the molecular sieve was determined by NMR characterization; the reaction conversion rate and the yield of each fraction were calculated from the actual boiling point data of the product; and the pour point of diesel oil was detected by a fully automatic pour point tester.

[0127] Example 1

[0128] (1) The sheet-like ZSM-5 molecular sieve (a-axis dimension -150nm, b-axis dimension -60nm, c-axis dimension -700nm, silicon-to-aluminum ratio 100, Na2O content 0.12%, specific surface area 405m²) 2 / g, pore volume 0.22cm 3 The surface acid content (calculated as 14%) of Ga-ZSM-5 heteroatom molecular sieve was obtained by mixing Ga-ZSM-5 with a 0.02 mol / L ammonium fluorosilicate and a 0.02 mol / L gallium nitrate mixed solution at a solid-liquid ratio of 1:30 and treating at 90 °C for 4 h. The mixture was then filtered, the solid was washed with water until neutral, dried at 100 °C for 12 h, and calcined at 500 °C for 2 h in air to obtain Ga-ZSM-5 heteroatom molecular sieve. From its SEM image (Figure 1), it can be clearly seen that the Ga-ZSM-5 molecular sieve still maintains a plate-like morphology. The Ga-ZSM-5 heteroatom molecular sieve exhibits... 71 Solid-state NMR characterization (Figure 2) showed that Ga atoms were in a four-coordinated state and there was no signal peak of non-framework Ga atoms at 0 ppm, indicating that all Ga atoms were doped into the ZSM-5 molecular sieve framework.

[0129] (2) According to the molecular sieve mother liquor composition, the molar ratio of SiO2:TPAOH:H2O is 1:1.2:800. Tetraethyl orthosilicate and 25% tetrapropylammonium hydroxide are added to a certain amount of water, and then the Ga-ZSM-5 heteroatom molecular sieve obtained in step (1) is added. The mass ratio of the heteroatom molecular sieve added to the silicon source of the molecular sieve mother liquor (based on the mass of SiO2) is 80:1. After stirring evenly, it is transferred to a polytetrafluoroethylene stainless steel reactor and statically crystallized at 180℃ for 16h. The molecular sieve product is filtered and separated, washed with deionized water until the washing water is neutral, dried at 100℃ for 24h, and calcined at 550℃ for 3h to obtain the Ga-ZSM-5@Silicate-1 composite product.

[0130] The properties of the Ga-ZSM-5@Silicate-1 composite are as follows: SEM and TEM images of the Ga-ZSM-5@Silicate-1 composite (Figures 3 & 4) clearly show that the composite retains its plate-like morphology. Since the Silicate-1 layer is grown epitaxially to coat the core-phase Ga-ZSM-5 heteroatom molecular sieve, and both have the same topological structure, the core-shell structure of the composite product is not obvious. However, by comparing the dimensions of each axis of the composite (a-axis -190 nm, b-axis -100 nm, c-axis -740 nm) with the core-phase molecular sieve, the Silicate-1 layer thickness is found to be -20 nm. The Ga-ZSM-5@Silicate-1 composite exhibits typical MFI topological characteristic peaks (Figure 5). Using the raw material plate-like ZSM-5 molecular sieve as a standard, the relative crystallinity of the Ga-ZSM-5@Silicate-1 composite is 110%. The specific surface area of ​​the Ga-ZSM-5@Silicate-1 composite is 396 m². 2 / g, total pore volume is 0.23cm³ 3 / g, mesoporous pore volume accounts for 22.4% of the total pore volume; the silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the Ga-ZSM-5@Silicate-1 composite is 124, the Na2O mass content is 0.04%, and the Ga2O3 content is 1.5%; the pyridine infrared acid content of the Ga-ZSM-5@Silicate-1 composite is 0.31 mmol / g, the di-tert-butylpyridine infrared acid content is 0.01 mmol / g, and the calculated surface acid content is 3.2%.

[0131] (3) The Ga-ZSM-5@Silicate-1 composite and γ-alumina (specific surface area 460 m²) were added. 2 / g, pore volume 1.2cm 3 / g) Mixed at a molecular sieve: alumina dry basis mass ratio of 71:29, then 15% nitric acid solution was added to the mixture to make a catalyst slurry with a solid content of 50%, which was kneaded, extruded and shaped, and the shaped carrier was dried at a constant temperature of 120℃ for 3h and then calcined at 550℃ for 3h in air atmosphere.

[0132] (4) Using 100g of carrier as a standard, prepare a mixed aqueous solution of nickel nitrate and ammonium metatungstate according to the content of nickel oxide 3% and tungsten oxide 13% in the catalyst. Load the active metal using the equal volume impregnation method. After loading the metal, dry the carrier at 120℃ for 3h and then calcine it at 500℃ for 3h in air atmosphere to obtain the hydrogenation-modified catalyst.

[0133] The hydrogenation catalyst provided in this embodiment, based on its weight, contains 60% Ga-ZSM-5@Silicate-1 composite, 24% alumina, 3% NiO, and 13% WO3, and is designated as A-1; the specific surface area of ​​the hydrogenation catalyst is 320 m². 2 / g, pore volume 0.38cm 3 / g.

[0134] Example 2

[0135] (1) The sheet-like ZSM-5 molecular sieve (a-axis dimension -150nm, b-axis dimension -60nm, c-axis dimension -700nm, silicon-to-aluminum ratio 100, Na2O content 0.12%, specific surface area 405m²) 2 / g, pore volume 0.22cm 3 A mixture of 0.05 mol / L ammonium fluorosilicate and 0.05 mol / L gallium nitrate (containing 0.25 mmol / g of pyridine and 0.035 mmol / g of di-tert-butylpyridine, with a surface acid content of 14%) was prepared with a solid-liquid ratio of 1:20 and treated at 80 °C for 5 h. The mixture was then filtered, and the solid was washed with water until neutral, dried at 100 °C for 12 h, and calcined at 500 °C for 2 h in air to obtain Ga-ZSM-5 heteroatom molecular sieve. The Ga-ZSM-5 heteroatom molecular sieve retained its plate-like morphology, with all Ga atoms incorporated into the molecular sieve framework.

[0136] (2) According to the molecular sieve mother liquor composition, the molar ratio of SiO2:TPAOH:H2O is 1:0.8:500. Tetraethyl orthosilicate and 25% tetrapropylammonium hydroxide are added to a certain amount of water, and then the Ga-ZSM-5 heteroatom molecular sieve obtained in step (1) is added. The mass ratio of the heteroatom molecular sieve added to the silicon source of the molecular sieve mother liquor (based on the mass of SiO2) is 60:1. After stirring evenly, it is transferred to a polytetrafluoroethylene stainless steel reactor and statically crystallized at 160℃ for 24h. The molecular sieve product is filtered and separated, washed with deionized water until the washing water is neutral, dried at 100℃ for 24h, and calcined at 550℃ for 3h to obtain the Ga-ZSM-5@Silicate-1 composite product.

[0137] The properties of the Ga-ZSM-5@Silicate-1 composite are as follows: SEM and TEM images of the Ga-ZSM-5@Silicate-1 composite show that the composite still maintains a plate-like morphology. The a-axis dimension of the composite is -250 nm, the b-axis dimension is -160 nm, and the c-axis dimension is -800 nm. The Silicate-1 layer thickness is -50 nm by comparing the dimensions of the composite with those of the core-phase molecular sieve. The Ga-ZSM-5@Silicate-1 composite exhibits typical MFI topological characteristic peaks. Using plate-like ZSM-5 molecular sieve as a standard, the relative crystallinity of the Ga-ZSM-5@Silicate-1 composite is 118%. The specific surface area of ​​the Ga-ZSM-5@Silicate-1 composite is 384 m². 2 / g, total pore volume is 0.25cm³ 3 / g, mesoporous pore volume accounts for 16.2% of the total pore volume; the silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the Ga-ZSM-5@Silicate-1 composite is 155, the Na2O mass content is 0.03%, and the Ga2O3 content is 2.9%; the pyridine infrared acid content of the Ga-ZSM-5@Silicate-1 composite is 0.39 mmol / g, the di-tert-butylpyridine infrared acid content is 0.006 mmol / g, and the calculated surface acid content is 1.5%.

[0138] (3) The Ga-ZSM-5@Silicate-1 composite and γ-alumina (specific surface area 460 m²) were added. 2 / g, pore volume 1.2cm 3 / g) Mixed at a molecular sieve: alumina dry basis mass ratio of 59:41, then 15% nitric acid solution was added to the mixture to make a catalyst slurry with a solid content of 50%, which was kneaded, extruded and shaped, and the shaped carrier was dried at 120℃ for 3h and then calcined at 550℃ for 3h in air atmosphere.

[0139] (4) Using 100g of support as a standard, prepare a mixed aqueous solution of nickel nitrate and ammonium metatungstate according to the content of nickel oxide in the catalyst being 2.5% and the content of tungsten oxide being 12.5%. Load the active metal using the equal volume impregnation method. After loading the metal, dry the support at 120℃ for 3h and then calcine it at 500℃ for 3h in an air atmosphere to obtain the hydrogenation catalyst.

[0140] The hydrogenation catalyst provided in this embodiment, based on its weight, contains 50% Ga-ZSM-5@Silicate-1 composite, 35% alumina, 2.5% NiO, and 12.5% ​​WO3, and is designated as A-2; the specific surface area of ​​the hydrogenation catalyst is 300 m². 2 / g, pore volume 0.41cm 3 / g.

[0141] Example 3

[0142] (1) The sheet-like ZSM-5 molecular sieve (a-axis dimension -150nm, b-axis dimension -60nm, c-axis dimension -700nm, silicon-to-aluminum ratio 100, Na2O content 0.12%, specific surface area 405m²) 2 / g, pore volume 0.22cm 3 A mixture of 0.01 mol / L ammonium fluorosilicate and 0.01 mol / L gallium nitrate infrared solution (containing 0.25 mmol / g of pyridine and 0.035 mmol / g of di-tert-butylpyridine, with a calculated surface acid content of 14%) was mixed with a solid-liquid ratio of 1:50 and treated at 100 °C for 3 h. The mixture was then filtered, and the solid was washed with water until neutral, dried at 100 °C for 12 h, and calcined at 500 °C for 2 h in air to obtain Ga-ZSM-5 heteroatom molecular sieve. The Ga-ZSM-5 heteroatom molecular sieve retained its plate-like morphology, with all Ga atoms doped into the molecular sieve framework.

[0143] (2) According to the molecular sieve mother liquor composition, the molar ratio of SiO2:TPAOH:H2O is 1:1.5:1000. Tetraethyl orthosilicate and 25% tetrapropylammonium hydroxide are added to a certain amount of water, and then the Ga-ZSM-5 heteroatom molecular sieve obtained in step (1) is added. The mass ratio of the heteroatom molecular sieve added to the silicon source of the molecular sieve mother liquor (based on the mass of SiO2) is 120:1. After stirring evenly, it is transferred to a polytetrafluoroethylene stainless steel reactor and statically crystallized at 190℃ for 8 hours. The molecular sieve product is filtered and separated, washed with deionized water until the washing water is neutral, dried at 100℃ for 24 hours, and calcined at 550℃ for 3 hours to obtain the Ga-ZSM-5@Silicate-1 composite product.

[0144] The properties of the Ga-ZSM-5@Silicate-1 composite are as follows: SEM and TEM images of the Ga-ZSM-5@Silicate-1 composite show that the composite still maintains a plate-like morphology. The a-axis dimension of the composite is -170 nm, the b-axis dimension is -80 nm, and the c-axis dimension is -720 nm. By comparing the dimensions of each axis of the composite with those of the core-phase molecular sieve, the Silicate-1 layer thickness is found to be -10 nm. The Ga-ZSM-5@Silicate-1 composite exhibits typical MFI topological characteristic peaks. Using plate-like ZSM-5 molecular sieve as a standard, the relative crystallinity of the Ga-ZSM-5@Silicate-1 composite is 105%. The specific surface area of ​​the Ga-ZSM-5@Silicate-1 composite is 402 m². 2 / g, total pore volume is 0.21cm³ 3 / g, mesoporous pore volume accounts for 19.8% of the total pore volume; the silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the Ga-ZSM-5@Silicate-1 composite is 108, the Na2O mass content is 0.05%, and the Ga2O3 content is 0.6%; the pyridine infrared acid content of the Ga-ZSM-5@Silicate-1 composite is 0.28 mmol / g, the di-tert-butylpyridine infrared acid content is 0.012 mmol / g, and the calculated surface acid content is 4.2%.

[0145] (3) The Ga-ZSM-5@Silicate-1 composite and γ-alumina (specific surface area 460 m²) were added. 2 / g, pore volume 1.2cm 3 / g) Mix the molecular sieve and alumina dry basis in a ratio of 85:15, then add 15% nitric acid solution to the mixture to make a catalyst slurry with a solid content of 50%, knead, extrude and form into strips, and then dry the formed carrier at a constant temperature of 120°C for 3 hours and calcinate at 550°C in air for 3 hours.

[0146] (4) Using 100g of support as a standard, prepare a mixed aqueous solution of nickel nitrate and ammonium metatungstate according to the content of nickel oxide 4% and tungsten oxide 14% in the catalyst. Load the active metal using the equal volume impregnation method. After loading the metal, dry the support at 120℃ for 3h and then calcine it at 500℃ for 3h in air atmosphere to obtain the hydrogenation catalyst.

[0147] The hydrogenation catalyst provided in this embodiment, based on its weight, contains 70% Ga-ZSM-5@Silicate-1 composite, 12% alumina, 4% NiO, and 14% WO3, and is designated as A-3; the specific surface area of ​​the hydrogenation catalyst is 352 m². 2 / g, pore volume 0.36cm 3 / g.

[0148] Example 4

[0149] The preparation steps of the Ga-ZSM-5@Silicate-1 composite are the same as in Example 1, except that in step (1), the a-axis dimension of the plate-like ZSM-5 molecular sieve is -200nm, the b-axis dimension is -100nm, the c-axis dimension is -1000nm, the silicon-aluminum ratio is 80, the Na2O content is 0.14%, and the specific surface area is 417m². 2 / g, pore volume 0.21cm 3 The surface acid content was calculated to be 12.5%, with pyridine infrared acidity of 0.32 mmol / g and di-tert-butylpyridine infrared acidity of 0.04 mmol / g. The properties of the obtained Ga-ZSM-5@Silicate-1 composite are as follows: SEM and TEM images of the Ga-ZSM-5@Silicate-1 composite show that the composite retains its plate-like morphology. The a-axis dimension of the composite is -250 nm, the b-axis dimension is -150 nm, and the c-axis dimension is -1050 nm. The Silicate-1 layer thickness was found to be -25 nm by comparing the dimensions of the composite with those of the core-phase molecular sieve. The Ga-ZSM-5@Silicate-1 composite exhibits typical MFI topological characteristic peaks. Using plate-like ZSM-5 molecular sieve as a standard, the relative crystallinity of the Ga-ZSM-5@Silicate-1 composite is 113%. The specific surface area of ​​the Ga-ZSM-5@Silicate-1 composite is 390 m² / g. 2 / g, total pore volume is 0.22cm³ 3 / g, mesoporous pore volume accounts for 21.0% of the total pore volume; the silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the Ga-ZSM-5@Silicate-1 composite is 102, the Na2O mass content is 0.02%, and the Ga2O3 content is 1.4%; the pyridine infrared acid content of the Ga-ZSM-5@Silicate-1 composite is 0.41 mmol / g, the di-tert-butylpyridine infrared acid content is 0.008 mmol / g, and the calculated surface acid content is 1.95%.

[0150] The hydrogenation catalyst was prepared according to the method of Example 1. The hydrogenation catalyst provided in this example, based on its weight, contains 60% Ga-ZSM-5@Silicate-1 composite, 24% alumina, 3% NiO, and 13% WO3, and is designated as A-4; the specific surface area of ​​the hydrogenation catalyst is 311 m². 2 / g, pore volume 0.37cm 3 / g.

[0151] Example 5

[0152] The preparation steps of the Ga-ZSM-5@Silicate-1 composite are the same as in Example 1, except that in step (1), the a-axis dimension of the plate-like ZSM-5 molecular sieve is -80nm, the b-axis dimension is -30nm, the c-axis dimension is -400nm, the silicon-aluminum ratio is 150, the Na2O content is 0.06%, and the specific surface area is 380m². 2 / g, pore volume 0.18cm 3 The surface acid content was calculated to be 12.9%, with pyridine infrared acidity of 0.17 mmol / g and di-tert-butylpyridine infrared acidity of 0.022 mmol / g. The properties of the obtained Ga-ZSM-5@Silicate-1 complex are as follows: SEM and TEM images of the Ga-ZSM-5@Silicate-1 complex show that the complex retains its plate-like morphology. The a-axis dimension of the complex is -110 nm, the b-axis dimension is -60 nm, and the c-axis dimension is -430 nm. The Silicate-1 layer thickness was found to be -15 nm by comparing the dimensions of the complex with those of the core-phase molecular sieve. The Ga-ZSM-5@Silicate-1 complex exhibits typical MFI topological characteristic peaks. Using plate-like ZSM-5 molecular sieve as a standard, the relative crystallinity of the Ga-ZSM-5@Silicate-1 complex is 111%. The specific surface area of ​​the Ga-ZSM-5@Silicate-1 complex is 365 m² / g. 2 / g, total pore volume is 0.20cm³ 3 / g, mesoporous pore volume accounts for 19.2% of the total pore volume; the silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the Ga-ZSM-5@Silicate-1 composite is 182, the Na2O mass content is 0.02%, and the Ga2O3 content is 1.2%; the pyridine infrared acid content of the Ga-ZSM-5@Silicate-1 composite is 0.21 mmol / g, the di-tert-butylpyridine infrared acid content is 0.007 mmol / g, and the calculated surface acid content is 3.3%.

[0153] The hydrogenation catalyst was prepared according to the method of Example 1. The hydrogenation catalyst provided in this example, based on its weight, contains 60% Ga-ZSM-5@Silicate-1 composite, 24% alumina, 3% NiO, and 13% WO3, and is designated as A-5; the specific surface area of ​​the hydrogenation catalyst is 296 m². 2 / g, pore volume 0.35cm 3 / g.

[0154] Example 6

[0155] The preparation steps of the Ga-ZSM-5@Silicate-1 composite are the same as in Example 1, except that: in step (1), gallium chloride is used instead of gallium nitrate as the heteroatom precursor, and in step (2), methyl orthosilicate is used instead of tetraethyl orthosilicate as the silicon source. The properties of the obtained Ga-ZSM-5@Silicate-1 composite are as follows: SEM and TEM images of the Ga-ZSM-5@Silicate-1 composite show that the composite still maintains a plate-like morphology. The a-axis dimension of the composite is -210 nm, the b-axis dimension is -120 nm, and the c-axis dimension is -760 nm. The Silicate-1 layer thickness is -30 nm by comparing the dimensions of each axis of the composite with those of the nucleus-phase molecular sieve. The Ga-ZSM-5@Silicate-1 composite exhibits typical MFI topological characteristic peaks. Using the plate-like ZSM-5 molecular sieve as a standard, the relative crystallinity of the Ga-ZSM-5@Silicate-1 composite is 115%. The specific surface area of ​​the Ga-ZSM-5@Silicate-1 composite is 389 m². 2 / g, total pore volume is 0.20cm³ 3 / g, mesoporous pore volume accounts for 17.9% of the total pore volume; the silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the Ga-ZSM-5@Silicate-1 composite is 131, the Na2O mass content is 0.04%, and the Ga2O3 content is 1.6%; the pyridine infrared acid content of the Ga-ZSM-5@Silicate-1 composite is 0.3 mmol / g, the di-tert-butylpyridine infrared acid content is 0.009 mmol / g, and the calculated surface acid content is 3%.

[0156] The hydrogenation catalyst was prepared according to the method of Example 1. The hydrogenation catalyst provided in this example, based on its weight, contains 60% Ga-ZSM-5@Silicate-1 composite, 24% alumina, 3% NiO, and 13% WO3, and is designated as A-6; the specific surface area of ​​the hydrogenation catalyst is 332 m². 2 / g, pore volume 0.37cm 3 / g.

[0157] Example 7

[0158] The preparation steps of the Ga-ZSM-5@Silicate-1 composite are the same as in Example 1, except that in step (1), the ZSM-5 molecular sieve is treated with a mixture of 0.07 mol / L ammonium fluorosilicate and 0.07 mol / L gallium nitrate. The properties of the obtained Ga-ZSM-5@Silicate-1 composite are as follows: SEM and TEM images of the Ga-ZSM-5@Silicate-1 composite show that the composite still maintains a plate-like morphology. The a-axis dimension of the composite is -190 nm, the b-axis dimension is -100 nm, and the c-axis dimension is -740 nm. The Silicate-1 layer thickness is -20 nm by comparing the dimensions of each axis of the composite with those of the core phase molecular sieve. The Ga-ZSM-5@Silicate-1 composite exhibits typical MFI topological characteristic peaks. Using the plate-like ZSM-5 molecular sieve as a standard, the relative crystallinity of the Ga-ZSM-5@Silicate-1 composite is 102%. The specific surface area of ​​the Ga-ZSM-5@Silicate-1 composite is 336 m². 2 / g, total pore volume is 0.27cm³ 3 / g, mesoporous pore volume accounts for 27.1% of the total pore volume; the silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the Ga-ZSM-5@Silicate-1 composite is 226, the Na2O mass content is 0.02%, and the Ga2O3 content is 3.8%; the pyridine infrared acid content of the Ga-ZSM-5@Silicate-1 composite is 0.24 mmol / g, the di-tert-butylpyridine infrared acid content is 0.012 mmol / g, and the calculated surface acid content is 5.0%.

[0159] The hydrogenation catalyst was prepared according to the method of Example 1. The hydrogenation catalyst provided in this example, based on its weight, contains 60% Ga-ZSM-5@Silicate-1 composite, 24% alumina, 3% NiO, and 13% WO3, and is designated as A-7; the specific surface area of ​​the hydrogenation catalyst is 275 m². 2 / g, pore volume 0.40cm 3 / g.

[0160] Example 8

[0161] The preparation steps of the Ga-ZSM-5@Silicate-1 composite are the same as in Example 1, except that tetrapropylammonium bromide is used instead of tetrapropylammonium hydroxide in step (2). The properties of the obtained Ga-ZSM-5@Silicate-1 composite are as follows: SEM and TEM images of the Ga-ZSM-5@Silicate-1 composite show that the composite still maintains a plate-like morphology. The a-axis dimension of the composite is -190 nm, the b-axis dimension is -100 nm, and the c-axis dimension is -740 nm. The Silicate-1 layer thickness is -20 nm by comparing the dimensions of each axis of the composite with those of the core phase molecular sieve. The Ga-ZSM-5@Silicate-1 composite exhibits typical MFI topological characteristic peaks. Using the plate-like ZSM-5 molecular sieve as a standard, the relative crystallinity of the Ga-ZSM-5@Silicate-1 composite is 106%. The specific surface area of ​​the Ga-ZSM-5@Silicate-1 composite is 382 m². 2 / g, total pore volume is 0.21cm³ 3 / g, mesoporous pore volume accounts for 20.2% of the total pore volume; the silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the Ga-ZSM-5@Silicate-1 composite is 117, the Na2O mass content is 0.03%, and the Ga2O3 content is 1.6%; the pyridine infrared acid content of the Ga-ZSM-5@Silicate-1 composite is 0.34 mmol / g, the di-tert-butylpyridine infrared acid content is 0.013 mmol / g, and the calculated surface acid content is 3.8%.

[0162] The hydrogenation catalyst was prepared according to the method of Example 1. The hydrogenation catalyst provided in this example, based on its weight, contains 60% Ga-ZSM-5@Silicate-1 composite, 24% alumina, 3% NiO, and 13% WO3, and is designated as A-8; the specific surface area of ​​the hydrogenation catalyst is 322 m². 2 / g, pore volume 0.38cm 3 / g.

[0163] Example 9

[0164] The preparation steps of the composite and the hydrogenation catalyst are the same as in Example 1, except that: in step (1), the ZSM-5 molecular sieve is first treated with ammonium fluorosilicate (in accordance with step (1) of Example 1, except that gallium nitrate is not introduced into the solution), and then the molecular sieve is loaded with Ga atoms by impregnation with gallium nitrate solution of the same amount in equal volume. Step (2) is the same as in Example 1.

[0165] The properties of the obtained Ga-ZSM-5 heteroatom molecular sieve are as follows: The Ga-ZSM-5 heteroatom molecular sieve still exhibits a plate-like morphology, with dimensions of -150 nm (a-axis), -60 nm (b-axis), and -700 nm (c-axis); the Ga-ZSM-5 heteroatom molecular sieve displays typical MFI topological characteristic peaks; using the plate-like ZSM-5 molecular sieve as a standard, the relative crystallinity of the Ga-ZSM-5 heteroatom molecular sieve is 95%; the specific surface area of ​​the Ga-ZSM-5 heteroatom molecular sieve is 381 m². 2 / g, total pore volume is 0.25cm³ 3 / g, mesoporous pore volume accounts for 29.2% of the total pore volume; the Si / Al ratio (SiO2 / Al2O3 molar ratio) of Ga-ZSM-5 heteroatom molecular sieve is 115, and the Na2O mass content is 0.05%; the pyridine infrared acid content of Ga-ZSM-5 heteroatom molecular sieve is 0.33 mmol / g, the di-tert-butylpyridine infrared acid content is 0.05 mmol / g, and the calculated surface acid content is 15%.

[0166] The hydrogenation catalyst provided in Example 9, based on its weight, contains 60% Ga-ZSM-5 heteroatom molecular sieve, 24% alumina, 3% NiO, and 13% WO3, and is designated as A-9; the specific surface area of ​​the hydrogenation catalyst is 300 m². 2 / g, pore volume 0.37cm 3 / g.

[0167] Comparative Example 1

[0168] The preparation steps of the hydrogenation catalyst are the same as in Example 1, except that steps (1) and (2) are omitted, that is, plate-like ZSM-5 molecular sieves are directly used instead of Ga-ZSM-5@Silicate-1 composites. The properties of the plate-like ZSM-5 molecular sieves are as follows: a-axis dimension -150nm, b-axis dimension -60nm, c-axis dimension -700nm, silicon-aluminum ratio 100, Na2O content 0.12%, specific surface area 405m². 2 / g, pore volume 0.22cm 3 / g, pyridine infrared acidity is 0.25mmol / g, di-tert-butylpyridine infrared acidity is 0.035mmol / g, and the surface acidity is calculated to be 14%.

[0169] The hydrogenation catalyst provided in Comparative Example 1, based on its weight, contains 60% H-ZSM-5 molecular sieve, 24% alumina, 3% NiO, and 13% WO3, and is designated as C-1; the specific surface area of ​​the hydrogenation catalyst is 315 m². 2 / g, pore volume 0.36cm 3 / g.

[0170] Comparative Example 2

[0171] The preparation steps of the composite and hydrogenation catalyst are the same as in Example 1, except that gallium nitrate, a heteroatom metal precursor, is not added in step (1). The properties of the obtained ZSM-5@Silicate-1 composite are as follows: SEM and TEM images of the ZSM-5@Silicate-1 composite show that the composite still maintains a plate-like morphology. The dimensions of the composite are a-axis dimension -190nm, b-axis dimension -100nm, and c-axis dimension -740nm. Compared with the core phase molecular sieve, the Silicate-1 layer thickness is -20nm. The ZSM-5@Silicate-1 composite exhibits typical MFI topological characteristic peaks. Using the plate-like ZSM-5 molecular sieve as a standard, the relative crystallinity of the ZSM-5@Silicate-1 composite is 114%. The specific surface area of ​​the ZSM-5@Silicate-1 composite is 405m². 2 / g, total pore volume is 0.23cm³ 3 / g, mesoporous pore volume accounts for 23.0% of the total pore volume; the silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) of the ZSM-5@Silicate-1 composite is 121, and the Na2O mass content is 0.04%; the pyridine infrared acid content of the ZSM-5@Silicate-1 composite is 0.20 mmol / g, the di-tert-butylpyridine infrared acid content is 0.007 mmol / g, and the calculated surface acid content is 10%.

[0172] The hydrogenation catalyst provided in Comparative Example 2, based on its weight, contains 60% ZSM-5@Silicate-1 composite, 24% alumina, 3% NiO, and 13% WO3, and is designated as C-2; the specific surface area of ​​the hydrogenation catalyst is 333 m². 2 / g, pore volume 0.39cm 3 / g.

[0173] Comparative Example 3

[0174] The preparation steps of the hydrogenation catalyst are the same as in Example 1, except that: in step (1), a traditional ZSM-5 molecular sieve (irregular morphology (see Figure 6), silicon-to-aluminum ratio 96, Na2O content 0.15%, specific surface area 420 m²) is used. 2 / g, pore volume 0.18cm 3 / g, pyridine infrared acid content 0.27mmol / g, di-tert-butylpyridine infrared acid content 0.032mmol / g, calculated surface acid percentage 12%) to replace the plate-like ZSM-5 molecular sieve. The properties of the obtained Ga-ZSM-5@Silicate-1 composite are as follows: The Ga-ZSM-5@Silicate-1 composite still maintains an irregular morphology (Figure 7). Compared with the core phase molecular sieve, the Silicate-1 layer thickness is -20nm, the silicon-aluminum ratio is 117, the Na2O content is 0.03%, and the specific surface area is 413m². 2 / g, pore volume 0.20cm 3 / g, pyridine infrared acidity is 0.34mmol / g, di-tert-butylpyridine infrared acidity is 0.015mmol / g, and the surface acidity is calculated to be 4.4%.

[0175] The hydrogenation catalyst provided in Comparative Example 3, based on its weight, contains 60% Ga-ZSM-5@Silicate-1 composite, 24% alumina, 3% NiO, and 13% WO3, and is designated as C-4; the specific surface area of ​​the hydrogenation catalyst is 331 m². 2 / g, pore volume 0.37cm 3 / g.

[0176] Evaluation Example 1

[0177] The hydrocracking evaluation tests of straight-run diesel oil prepared in the examples and the catalysts in the comparative examples were conducted on a small fixed-bed unit. The properties of the feedstock are shown in Table 1. The evaluation unit adopted a single-stage series one-pass process flow. The first reactor was loaded with a conventional refining catalyst (characteristics of the hydrorefined oil are shown in Table 2), and the second reactor was loaded with the hydrocracking catalysts of the examples and comparative examples of this invention. The evaluation results are shown in Table 2. Process conditions: feedstock was straight-run diesel oil; cracking temperature: 350℃; reaction pressure: 6 MPa; volume hourly space velocity: 1.0 h⁻¹. -1 Hydrogen-to-oil volume ratio 500, sulfur content of hydrotreated oil 80 ppm, nitrogen content of hydrotreated oil 1 ppm.

[0178] The properties of the crude oil used in the hydrocracking evaluation experiment are shown in Table 1:

[0179] Table 1 Properties of Crude Oil

[0180] Table 2 Evaluation results of the hydrogenation catalyst of the present invention

[0181] As shown in Table 2, a comparison of the evaluation results of Example 1 and Comparative Example 1 reveals that: due to the lack of Ga atom doping and Silicate-1 layer coating, the isomerism of diesel hydrocarbon molecules is reduced and the hydrocarbon molecules are excessively cracked, resulting in a decrease in the yield of low-pour-point diesel fraction and an increase in the pour point of diesel compared to the Ga-ZSM-5@Silicate-1 composite catalyst prepared in this invention; a comparison of the evaluation results of Example 1 and Comparative Example 2 reveals that: when Ga heteroatom doping is lacking, although... However, by reducing the acid content on the surface of the molecular sieve through ammonium fluorosilicate treatment and Silicate-1 layer coating, the yield of low-pour-point diesel fraction can be effectively improved. However, due to the low total acid content of the molecular sieve, the isomerization effect of diesel hydrocarbon molecules is poor, resulting in a higher pour point of the low-pour-point diesel product. By comparing the evaluation results of Example 1 and Comparative Example 3, it can be found that the traditional ZSM-5 molecular sieve-based composite lacks the mass transfer effect of the plate-like composite on the large molecular hydrocarbons in the diesel feedstock, which leads to a decrease in its isomerization performance of diesel hydrocarbon molecules, resulting in a higher pour point of the low-pour-point diesel product.

Claims

1. A Ga-ZSM-5@Silicate-1 composite, characterized in that, The composite comprises: a Ga-ZSM-5 heteroatom molecular sieve and a Silicate-1 layer coating the Ga-ZSM-5 heteroatom molecular sieve, and the composite has a plate-like morphology.

2. The complex according to claim 1, wherein, The surface acid content of the complex is 2%-4.2%, and the surface acid content is calculated as surface acid content / total acid content × 100%. The total acid content is characterized by pyridine infrared spectroscopy, and the surface acid content is characterized by di-tert-butylpyridine infrared spectroscopy.

3. The complex according to claim 1 or 2, wherein, The total acidity of the complex is 0.1 mmol / g-0.5 mmol / g, preferably 0.2 mmol / g-0.4 mmol / g; and / or The surface acidity of the complex is 0.002 mmol / g to 0.02 mmol / g, preferably 0.005 to 0.015 mmol / g.

4. The complex according to any one of claims 1-3, wherein, The composite is presented as hexagonal prism flakes; and / or The composite has a b-axis dimension perpendicular to the (010) crystal plane of 30nm-200nm, preferably 60-160nm; the ratio of the a-axis dimension perpendicular to the (100) crystal plane to the b-axis dimension is (1:1)-(5:1); and the ratio of the c-axis dimension parallel to the (010) and (100) crystal planes to the b-axis dimension is (5:1)-(15:1).

5. The complex according to any one of claims 1-4, wherein, The specific surface area of ​​the composite is 250 m². 2 / g-500m 2 / g, preferably 300m 2 / g-450m 2 / g; and / or The total pore volume of the composite is 0.15 cm³. 3 / g-0.3cm 3 / g, preferably 0.2cm 3 / g-0.25cm 3 / g; and / or The mesoporous volume of the composite is 10%-30%, preferably 15%-25%.

6. The complex according to any one of claims 1-5, wherein, The silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the composite is 100-300, preferably 120-200; and / or Based on the total weight of the complex, the mass content of Ga heteroatoms (in oxides) is ≤3.0%, preferably ≤2.0%, and more preferably 0.3-1.5%; and / or the mass content of Na₂O is ≤0.3%, preferably ≤0.1%; and / or The complex exhibits typical MFI topological diffraction peaks. and / or The average thickness of the Silicate-1 layer is 5nm-50nm, preferably 20nm-30nm.

7. A method for preparing a Ga-ZSM-5@Silicate-1 composite, characterized in that: The method includes: (1) The sheet-like ZSM-5 molecular sieve was treated with a mixed solution of ammonium fluorosilicate and Ga precursor, and the resulting solid was dried and calcined to obtain Ga-ZSM-5 heteroatom molecular sieve; (2) The Ga-ZSM-5 heteroatom molecular sieve obtained in step (1) is mixed with silicon source, template agent and water to obtain crystallization solution, and then crystallization is carried out; the obtained solid is dried and calcined.

8. The method according to claim 7, wherein, The conditions processed in step (1) include: The temperature is 60℃-120℃, preferably 80℃-100℃; and / or The time is 3-5 hours; and / or The concentration of ammonium fluorosilicate in the mixed solution is 0.01 mol / L to 0.05 mol / L; and / or The concentration of Ga precursor in the mixed solution is 0.01 mol / L to 0.05 mol / L; and / or The solid-liquid ratio of the sheet-like ZSM-5 molecular sieve to the mixed solution is 1:20-50 (g:mL).

9. The method according to claim 7 or 8, wherein, In step (1): The drying conditions include: a temperature of 80℃-120℃ and a time of 12h-24h; and / or The calcination conditions include: calcination atmosphere is air, calcination temperature is 400℃-500℃, and calcination time is 2h-4h.

10. The method according to any one of claims 7-9, wherein, The specific surface area of ​​the plate-like ZSM-5 molecular sieve is 300 m². 2 / g-500m 2 / g, preferably 350m 2 / g-450m 2 / g; and / or a total pore volume of 0.15cm³. 3 / g-0.3cm 3 / g, preferably 0.2cm 3 / g-0.25cm 3 / g; and / or mesoporous pore volume percentage of 5%-20%, preferably 10%-15%; The b-axis dimension perpendicular to the (010) crystal plane in the sheet-like ZSM-5 molecular sieve is 20nm-150nm, preferably 50-100nm; the ratio of the a-axis dimension perpendicular to the (100) crystal plane to the b-axis dimension is (2:1)-(5:1), and the ratio of the c-axis dimension parallel to the (010) crystal plane and (100) to the b-axis dimension is (6:1)-(15:1). The silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of the plate-like ZSM-5 molecular sieve is 80-250, preferably 100-150; The sheet-like ZSM-5 molecular sieve, based on weight, has a Na2O content of ≤0.3%, preferably ≤0.1%. The pyridine infrared acid content of the sheet-like ZSM-5 molecular sieve is 0.05 mmol / g-0.4 mmol / g, preferably 0.1 mmol / g-0.3 mmol / g; the di-tert-butylpyridine infrared acid content is 0.01 mmol / g-0.04 mmol / g, preferably 0.02-0.03 mmol / g; and the surface acid content is 10%-20%. The Ga precursor is at least one of gallium chloride and gallium nitrate.

11. The method according to any one of claims 7-10, wherein, In step (2): In the crystallization solution, the silicon source is SiO2, and the ratio of SiO2:template:H2O is 1:(0.6-1.5):(500-1000), preferably SiO2:template:H2O = 1:(0.8-1.2):(600-800); and / or The mass ratio of Ga-ZSM-5 heteroatom molecular sieve to silicon source (based on SiO2 content) is 50-150:1, preferably 80-120:1; and / or The silicon source is at least one of tetraethyl orthosilicate and methyl orthosilicate, more preferably tetraethyl orthosilicate; and / or The template agent is one or more of tetrapropylammonium hydroxide and tetrapropylammonium bromide.

12. The method according to any one of claims 7-11, wherein, In step (2): Crystallization conditions include: a temperature of 160℃-190℃, preferably 170℃-180℃; and / or a time of 6h-24h, preferably 12h-18h; and / or The drying conditions include: a temperature of 80-120℃ and a time of 12-24 hours; and / or The roasting conditions include: a temperature of 500-600℃ and a time of 2-6 hours.

13. The Ga-ZSM-5@Silicate-1 composite prepared by the method according to any one of claims 7-12.

14. The application of the Ga-ZSM-5@Silicate-1 composite according to any one of claims 1-6 and 13 in a hydrogenation catalyst; preferably, the hydrogenation catalyst is selected from one or more of diesel hydrocracking catalysts, catalytic cracking catalysts, and MTO catalysts.

15. A hydrogenation catalyst, characterized in that: The hydrogenation catalyst contains the Ga-ZSM-5@Silicate-1 complex according to any one of claims 1-6 and 13 and a hydrogenation active metal oxide. Preferably, the content of the Ga-ZSM-5@Silicate-1 complex is 40wt%-70wt%, more preferably 50wt%-60wt%, based on the total weight of the catalyst.

16. The catalyst according to claim 15, wherein, The catalyst contains 10 wt% to 40 wt%, preferably 20 wt% to 30 wt%, of a binder, preferably selected from γ-alumina, based on its total weight; and / or Based on the total weight of the catalyst, it contains 12wt%-20wt%, preferably 14wt%-17wt% of hydrogenation-active metal oxides; and / or The hydrogenation active metal is selected from metals of Group VIII and / or Group VIB, preferably containing metals of Group VIII and Group VIB, and more preferably, the mass content of Group VIII metal oxides is 2%-5% and the mass content of Group VIB metal oxides is 10%-15% based on the total weight of the catalyst. Preferably, The Group VIII metal is Ni and / or Co, more preferably Ni; and / or The group VIB metal is W and / or Mo, with W being more preferred.

17. The catalyst according to claim 15 or 16, wherein, The specific surface area of ​​the hydrogenation catalyst is 200 m². 2 / g-400m 2 / g, preferably 250m 2 / g-360m 2 / g; and / or a pore volume of 0.2cm 3 / g-0.5cm 3 / g, preferably 0.25cm 3 / g-0.35cm 3 / g.

18. A method for hydrogenation modification, characterized in that, The method includes: (a) After the diesel feedstock is mixed with hydrogen, it enters the hydrorefining reaction zone and reacts with the hydrorefining catalyst bed; (b) The hydrorefined product oil and gaseous products are introduced into the hydrocracking reaction zone and react with the hydrocracking catalyst bed. The effluent from the hydrocracking reaction is separated into gas, naphtha and low-pour-point diesel by gas-liquid separation and fractionation.

19. The method according to claim 18, wherein, Diesel fuel has the following characteristics: Density (20℃) ranges from 0.80 g / cm³ 3 -0.90g / cm 3 The preferred value is 0.82 g / cm³. 3 -0.86g / cm 3 The distillation range is 150℃-380℃, preferably 180℃-370℃; The sulfur content is 0.1-2.0 wt%, preferably 0.8-1.5 wt%; The nitrogen content is 10ppm-500ppm, preferably 50ppm-200ppm; Freezing point -10℃~25℃, preferably -5℃~10℃.

20. The method according to claim 18 or 19, wherein, The characteristics of the hydrorefined product oil include: nitrogen content <10ppm, preferably <5ppm; sulfur content <200ppm, preferably <100ppm; and / or The conditions in the hydrocracking reaction zone include: Reaction pressure 3MPa-10MPa, preferably 4MPa-8MPa; and / or Reaction temperature 300℃-400℃, preferably 320℃-370℃; and / or The volume hourly space velocity (VHSV) of the hydrocracking catalyst is 0.5 h⁻¹. -1 -3.0h -1 1.0h is preferred -1 -1.5h -1 ; and / or The hydrogen-to-oil volume ratio is 300-1000, preferably 500-800.

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