Hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention discloses a hydrogenation catalyst as well as a preparation method and application thereof. The hydrogenation catalyst comprises a carrier and active metal, the carrier is an aluminum oxide core wrapped by a carbon shell, the active metal is Mo and Ni, and on the basis of the weight of the catalyst, the content of MoO3 is 7.5 wt%-15.5 wt%, the content of NiO is 1.5 wt%-4.5 wt%, the content of carbon is 20 wt%-45 wt%, and the content of aluminum oxide is 35 wt%-70 wt%; and the ratio delta 1 of the content of the active metal in the shell layer to the content of the active metal in the core layer is 0.25: 1-0.75: 1. The preparation method comprises the following steps: (1) preparing active metal modified flour; (2) preparing active metal modified pseudo-boehmite microspheres; and (3) rolling the active metal modified flour and the active metal modified pseudo-boehmite microspheres for molding, then carrying out heat treatment, drying and roasting to obtain the hydrogenation catalyst. The catalyst disclosed by the invention has relatively high metal impurity capacity and relatively high Ca, Fe, Ni and V removal capacity, and is suitable for being used as a hydrogenation protection catalyst and a hydrodemetallization catalyst in a residual oil hydrogenation process.

Description

Technical Field

[0001] This invention belongs to the field of materials preparation, specifically relating to a hydrogenation catalyst, its preparation method, and its application. Background Technology

[0002] Metallic impurities such as Ca, Fe, Ni, and V in heavy oil can cause permanent poisoning when deposited on hydrotreating catalysts, a crucial factor to consider in heavy oil hydrotreating processes. Protective agents and hydrodemetallizing catalysts are key technologies in heavy oil hydrotreating, primarily responsible for removing most of the Ni and V metallic impurities from the feedstock, protecting downstream desulfurization (HDS) and denitrification (HDN) catalysts, and possessing a certain desulfurization capacity. Both types of catalysts require not only excellent metal removal capabilities but also high metal impurity tolerance. Since most metallic impurities in residual oil reside in gums and asphaltenes, which are the largest, most structurally complex, and most polar components in petroleum, they exhibit significant diffusion resistance. Demetallizing agents are constrained by the mass transfer and diffusion efficiency of the carrier, easily leading to pore blockage, severely uneven impurity deposition, and limited metal tolerance. All of these factors result in significant waste of internal catalyst space, preventing the maximization of individual catalyst efficiency. Therefore, these two types of catalysts must have large pore volume, pore size and good pore permeability to facilitate the diffusion and reaction of macromolecular substances such as asphaltene containing metal impurities in the residual oil feedstock, as well as the deposition of metal impurities.

[0003] CN114425374A discloses a residue oil hydrodemetallization catalyst and its preparation method. The catalyst includes a catalyst body composed of a support and active components supported on the support, and a carbon film on the outer surface of the catalyst body. The preparation process includes: (1) preparing a residue oil hydrodemetallization catalyst as the catalyst body; (2) soaking the catalyst body obtained in step (1) in a carbohydrate aqueous solution, drying it, and then carbonizing it to form a carbon film on the catalyst surface. This method prevents the carbon deposits, sulfides, and iron, calcium, and other deposits generated after the residue oil reacts violently at the active sites on the catalyst surface from blocking the catalyst channels and covering the active sites by covering the surface active centers with a carbon film. However, the carbon film on the catalyst surface prepared by this method has a relatively small pore size, which is not conducive to the diffusion of large molecular reactants into the catalyst interior; moreover, as the reaction proceeds, the gradual deposition of metal impurities can easily cause metal deposition on the catalyst surface and block the channels.

[0004] CN117000258A discloses a catalyst for hydrodemetallization of residual oil and its preparation method. The catalyst includes a catalyst body, a sub-outer layer and a macroporous alumina layer. The active metal is distributed in the catalyst body and the sub-outer layer, and the active metal content in the sub-outer layer is lower than that in the catalyst body. The thickness ratio of the macroporous alumina layer to the sub-outer layer is 3:5 to 3:2. The preparation process includes: (1) impregnating the support with active metal impregnation solution R1 and drying to obtain the catalyst body; (2) preparing a macroporous pseudoboehmite slurry; (3) mixing the macroporous pseudoboehmite slurry obtained in step (2) with active metal impregnation solution R1 in a certain proportion to obtain active metal impregnation solution R2; (4) wrapping the catalyst body obtained in step (1) with active metal impregnation solution R2 obtained in step (3) and drying to obtain the catalyst intermediate; (5) impregnating the catalyst intermediate obtained in step (4) with the macroporous pseudoboehmite slurry prepared in step (2), drying, and calcining to obtain the residue oil hydrodemetallization catalyst. Although the macroporous alumina layer on the surface of the catalyst prepared by this method has large pores that can accommodate more carbon deposits and has no active metal, thus avoiding a violent hydrogenation reaction on the outer surface, the catalyst surface prepared by this method has no active components, resulting in low hydrogenation reaction activity and affecting the overall activity improvement of the catalyst. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a hydrogenation catalyst and its preparation method. The catalyst shell of this invention consists of a carbon material with micron-sized pores and a low-concentration hydrogenation active component, while the core layer consists of alumina and a high-concentration hydrogenation active component. This catalyst exhibits high tolerance for metal impurities and high removal capabilities for Ca, Fe, Ni, and V, making it suitable as a hydrogenation protection catalyst and a hydrogenation demetallization catalyst in the hydrogenation process of residue oil.

[0006] The hydrogenation catalyst of the present invention comprises a support and an active metal, wherein the support is an alumina core encased in a carbon shell, and the active metals are Mo and Ni. Based on the weight of the catalyst, the MoO3 content is 7.5wt%-15.5wt%, the NiO content is 1.5wt%-4.5wt%, the carbon content is 20wt%-45wt%, and the alumina content is 35wt%-70wt%; the ratio δ1 of the shell active metal content to the core active metal content is 0.25:1-0.75:1.

[0007] In the hydrogenation catalyst of the present invention, the ratio δ2 of the carbon shell thickness to the radius of the alumina core is 1:1-1:4.

[0008] In the hydrogenation catalyst of the present invention, the pore size of the carbon shell is 0.5-30 μm, the area ratio of 0.5-30 μm pores per unit area is greater than 80%, and the proportion of 7.5-15 μm pores in the 0.5-30 μm pores is greater than 60%.

[0009] The method for preparing the hydrogenation catalyst of the present invention includes the following steps: (1) Mix flour with inorganic alkali and grind it to obtain pretreated flour. Then add nickel nitrate and ammonium heptamolybdate to the pretreated flour and mix them evenly to obtain active metal modified flour. (2) The pseudoboehmite was impregnated with an impregnation solution containing Mo and Ni, and the impregnated pseudoboehmite was dried to obtain active metal modified pseudoboehmite. (3) The active metal modified boehmite from step (2) was placed in a rotary forming machine and rolled to form active metal modified boehmite microspheres. (4) The active metal modified flour from step (1) and the active metal modified boehmite microspheres from step (3) are placed in a rotary forming machine to form a spherical shape to obtain the hydrogenation catalyst precursor; (5) The hydrogenation catalyst precursor from step (4) is placed in a sealed container for heat treatment. The treated material is then dried and calcined to obtain the hydrogenation catalyst.

[0010] In the method of the present invention, the flour mentioned in step (1) is wheat flour, wherein the protein content is 6%-20%, the starch content is 65%-75%, and the rest is moisture, ash, enzymes, fat and vitamins, etc.

[0011] In the method of the present invention, the inorganic alkali in step (1) is one or more of LiOH, KOH and NaOH, and the mass ratio of inorganic alkali to flour is 2:100-12:100, preferably 4:100-8:100.

[0012] In the method of the present invention, the peak intensity of the XRD pattern of the pretreated flour in step (1) at 2θ of 15º, 17º, 18º, and 23º is reduced by more than 60% compared with that of the flour raw material, preferably 75%-90%. The average grain size D corresponding to the peak position at 2θ of 15º is 6.5-8.5 nm, where D=Kλ / (Bcosθ), K is the Scherrer constant, λ is the diffraction wavelength of the target material, B is the half-width of the diffraction peak, and θ is the diffraction angle. The grinding is preferably carried out in a ball mill for a grinding time of 40-180 min, preferably 60-120 min.

[0013] In the method of this invention, the mass ratio of nickel nitrate added in step (1) to pretreated flour is 1:100-5:100, preferably 1.2:100-3:100. The mass ratio of ammonium heptamolybdate added to flour is 1:100-8:100, preferably 1.5:100-4.5:100. To improve the uniformity of the mixture, it is preferable to grind the mixture for 10-30 minutes.

[0014] In the method of the present invention, the Mo and Ni impregnation solution in step (2) is a phosphoric acid solution containing Mo and Ni. The Mo content in the solution is 5.5-10.5 g / 100 mL as MoO3, and the Ni content is 1.3-4.5 g / 100 mL as NiO. The amount of solution used is the saturated water absorption capacity of boehmite.

[0015] In the method of the present invention, the pseudoboehmite in step (2) can be prepared by any method, preferably pseudoboehmite with a pore size of 10-30 nm.

[0016] In the method of the present invention, the drying temperature in step (2) is 120-180℃ and the drying time is 2-8 hours.

[0017] In the method of this invention, the operating conditions of the rotary forming machine in step (3) are as follows: the tilt angle of the rotary table is 40-70º, the rotation speed of the rotary table is 10-30 rpm, and the forming time of the material in the rotary table is 45-120 min. During the ball forming process, an aqueous solution containing adhesive solvent can be sprayed into the material; the aqueous solution containing adhesive solvent is one or a mixture of several of the aqueous solutions of nitric acid, phosphoric acid, oxalic acid, and acetic acid, and the mass concentration of the solution is 1%-3%, preferably an aqueous solution of acetic acid.

[0018] In the method of this invention, the operating conditions of the rotary forming machine in step (4) are as follows: the tilt angle of the rotary table is 40-70º, the rotation speed of the rotary table is 10-30 rpm, and the forming time of the material in the rotary table is 30-45 min. During the ball forming process, an appropriate amount of deionized water can be sprayed into the material.

[0019] In the method of the present invention, the sealed container in step (5) is preferably a sealed high-pressure reactor, the volume of the hydrogenation catalyst precursor accounts for 30% to 70% of the volume of the sealed container, the heat treatment temperature is 40-90℃, and the treatment time is 60-120min.

[0020] In the method of the present invention, the drying temperature in step (5) is 120-180℃ and the drying time is 2-6 hours. The calcination conditions are: calcination temperature is 400-600℃, calcination time is 4-8 hours, and the calcination atmosphere is an inert atmosphere, which is one or more of argon, helium or nitrogen, preferably nitrogen.

[0021] The application of the hydrogenation catalyst of the present invention in the hydrotreating of heavy residue oil is specifically as a hydroprotective agent and / or a hydrodemetallization catalyst.

[0022] This invention first pretreats the flour. During pretreatment, alkaline substances are adsorbed onto the starch granule surface through hydrogen bonding. Under the combined action of mechanical force and alkaline substances, the starch molecular bonds are broken, generating shorter molecular chains and branched structures, thus improving the swelling, viscosity, and toughness of the starch. During catalyst molding, the core layer is active metal-modified boehmite, and the shell layer is active metal-modified flour. When the molded material is heated in a sealed high-pressure container, the shell flour undergoes deep fracture under the influence of the sealed environment, moisture, alkaline substances, and suitable temperature, and undergoes water absorption, swelling, and foaming reactions, forming micron-sized pore precursors on the catalyst surface. Due to the enhanced swelling, viscosity, and toughness of the starch, the micron-sized pore precursors on the catalyst surface are easily formed and maintain structural integrity. During calcination under an inert atmosphere, the shell flour undergoes a carbonization reaction, and the micron-sized pore precursors transform into interconnected micron-sized channels. The catalyst shell consists of carbon material containing micron-sized channels and a low-concentration hydrogenation active component, while the core layer consists of alumina and a high-concentration hydrogenation active component. During the hydrogenation reaction, the shell catalyst almost completely removes Ca and Fe from the residue feedstock and partially removes Ni and V. The reactants then diffuse into the catalyst core for Ni and V removal. The carbon material in the catalyst shell interacts well with the active components, promoting the formation of the highly active II phase and enhancing the shell's reactivity. Simultaneously, the high macropore content and good pore connectivity of the catalyst shell enhance its capacity to accommodate Ca, Fe, Ni, and V, effectively suppressing catalyst deactivation. The catalyst core layer has a high active metal content and is impregnated before the boehmite transforms into alumina, improving the interaction between the active components and the alumina support, thus increasing the catalyst's hydrogenation demetallization activity. The content of metal impurities in the reactants diffused into the catalyst core layer is significantly reduced, mitigating the blockage of the catalyst core layer pores by metal impurities. This allows for efficient utilization of the catalyst core, improving catalyst activity while extending its operating cycle. Attached Figure Description

[0023] Figure 1 The XRD patterns of the flour raw materials and pretreated flour in Example 1 are shown.

[0024] Figure 2 This is a SEM image of the cross-sectional shell of the sample prepared in Example 1. Detailed Implementation

[0025] The technical solution and effects of the present invention will be further illustrated below with reference to the embodiments, but the invention is not limited to the following embodiments. In the present invention, wt% represents mass fraction.

[0026] The pore structure of the samples was characterized using N2 physical adsorption-desorption, and the specific operation was as follows: An ASAP-2420 N2 physical adsorption-desorption instrument was used to characterize the pore structure of the samples. A small amount of sample was vacuum-treated at 300℃ for 3-4 hours, and finally, the product was placed under liquid nitrogen cryogenic conditions (-200℃) for nitrogen adsorption-desorption testing. The specific surface area was obtained according to the BET equation, and the pore volume and pore diameter distribution below 30 nm were obtained according to the BJH model.

[0027] The pore structure of the sample was characterized using a scanning electron microscope (SEM). The specific operation was as follows: The microstructure of the carrier was characterized using a JSM-7500F SEM with an accelerating voltage of 5 kV, an accelerating current of 20 µA, and a working distance of 8 mm.

[0028] The ratio δ1 of the active metal content in the catalyst shell to the active metal content in the core layer was determined by SEM-EDS micro-area analysis. During the measurement, the catalyst was cut into two hemispheres on average, ensuring that the cross-section after cutting was perpendicular to the direction of the electron beam of the scanning electron microscope. Twenty micro-areas in each of the catalyst shell and core layer were randomly selected, and the active metal content was measured and the average value was taken to calculate δ1.

[0029] The ratio δ2 of the catalyst shell thickness to the core radius was calculated by measuring the thickness of aluminum and carbon elements using SEM-EDS energy dispersive spectroscopy. During the measurement, the catalyst was cut into two hemispheres on average, ensuring that the cross-section after cutting was perpendicular to the direction of the electron beam of the scanning electron microscope. δ2 was calculated by averaging the thickness of aluminum and carbon elements in 20 spheres.

[0030] Method for measuring the proportion of 0.5-30μm pores: The material is cut and adhered to the scanning electron microscope (SEM) stage. The instrument is adjusted to acquire SEM images. The image area and the area of ​​0.5-30μm pores in the image are statistically measured using the image scale. The proportion of 0.5-30μm pores in the material is obtained by dividing the area of ​​0.5-30μm pores by the image area. Images are randomly selected during the measurement process, and the number of images is greater than 50, and the average value is calculated.

[0031] Method for measuring the proportion of 7.5-15μm pores: The material is cut and adhered to the scanning electron microscope (SEM) stage. The instrument is adjusted to acquire SEM images. The area of ​​0.5-30μm pores and the area of ​​pores with a size of 7.5-15μm are calculated by statistically measuring the image scale. The proportion of 7.5-15μm pores in the material is obtained by dividing the area of ​​7.5-15μm pores by the area of ​​0.5-30μm pores in the image. Images are randomly selected during the measurement process, and the number of images is greater than 50, and the average value is calculated. Example 1

[0032] (1) Weigh 100g of wheat flour (protein content 7.1%, carbohydrate content 66.2%) and 6.5g of sodium hydroxide. Mix the above materials evenly and grind the mixture in a grinder for 85 minutes to obtain pretreated flour. Weigh 100g of pretreated flour, 1.8g of nickel nitrate, and 2.6g of ammonium heptamolybdate. Mix the above materials evenly and grind the mixture in a grinder for 20 minutes to obtain active metal modified flour. The XRD patterns of the wheat flour raw materials and the pretreated flour are shown in [reference needed]. Figure 1 The average grain size D corresponding to the peak position 2θ of the pretreated flour at 15º is 7.2 nm; (2) Weigh an appropriate amount of pseudoboehmite (with a pore size of 18), and saturate the above material with a Mo-Ni-P solution with a MoO3 concentration of 7.5 g / 100 mL and a NiO concentration of 1.9 g / 100 mL. After impregnation, the material is dried at 140 °C for 4 hours to obtain active metal modified pseudoboehmite. (3) Place the active metal modified boehmite from step (2) into a rotary molding machine, adjust the tilt angle of the rotary table to 42º and the rotation speed of the rotary table to 20rpm, and spray an appropriate amount of 0.5% acetic acid aqueous solution onto the material in the rotary table through a sprayer. The material is molded in the rotary table for 70min to obtain active metal modified boehmite microspheres. (4) Place the active metal modified flour from step (1) and the active metal modified boehmite microspheres from step (3) into a rotary molding machine, control the tilt angle of the rotary table to be 42º and the rotation speed of the rotary table to be 20rpm, spray an appropriate amount of deionized water onto the material in the rotary table through a sprayer, and continue to roll the ball for 35min to obtain the hydrogenation catalyst precursor. (5) The hydrogenation catalyst precursor from step (4) was placed directly into a high-pressure reactor (the material occupied 50% of the reactor's reaction liner volume). After the reactor was sealed, it was heated at 60°C for 95 min. The heated material was then dried at 140°C for 4 hours. The dried material was calcined at 500°C for 6 hours under a nitrogen atmosphere to obtain the hydrogenation catalyst cat1 of this invention. The properties of the catalyst are shown in Table 1. The scanning electron microscope image of the cross-sectional shell of the catalyst after cutting is shown in Table 1. Figure 2 . Example 2

[0033] Same as Example 1, except that in step (1), sodium hydroxide is replaced with potassium hydroxide, the amount of potassium hydroxide added is 5.3 g, the grinding time is 95 minutes, the amount of nickel nitrate added is 2.3 g, and the amount of ammonium heptamolybdate added is 3.4 g. In step (2), the concentration of MoO3 in the Mo-Ni-P solution is 7 g / 100 mL, and the concentration of NiO is 1.8 g / 100 mL. In step (4), the rolling time is 40 minutes. In step (5), the heat treatment temperature is 70 °C, and the treatment time is 85 minutes. The hydrogenation catalyst cat2 of the present invention was obtained, and the properties of the catalyst are shown in Table 1. Example 3

[0034] Same as Example 1, except that in step (1), the amount of sodium hydroxide added is 4.3 g, the grinding time is 105 minutes, the amount of nickel nitrate added is 1.3 g, and the amount of ammonium heptamolybdate added is 1.8 g. In step (2), the concentration of MoO3 in the Mo-Ni-P solution is 8 g / 100 mL, and the concentration of NiO is 2.1 g / 100 mL. In step (4), the rolling time is 30 minutes. In step (5), the heat treatment temperature is 50 °C, and the treatment time is 105 minutes. The hydrogenation catalyst cat3 of the present invention was obtained, and the properties of the catalyst are shown in Table 1. Example 4

[0035] Same as Example 1, except that in step (1), sodium hydroxide is replaced with potassium hydroxide, the amount of potassium hydroxide added is 7.4 g, the grinding time is 75 minutes, the amount of nickel nitrate added is 2.8 g, and the amount of ammonium heptamolybdate added is 4 g. In step (2), the concentration of MoO3 in the Mo-Ni-P solution is 6.5 g / 100 mL, and the concentration of NiO is 1.7 g / 100 mL. In step (4), the rolling time is 45 minutes. In step (5), the heat treatment temperature is 80 °C, and the treatment time is 75 minutes. The hydrogenation catalyst cat4 of the present invention was obtained, and the properties of the catalyst are shown in Table 1.

[0036] Comparative Example 1 Same as Example 1, except that the wet material after molding in step (5) was not placed in a sealed container for heating treatment, but was directly placed in an oven for forced air heating treatment to obtain the hydrogenation demetallization catalyst cat5. Scanning electron microscopy revealed that no abundant micron-sized interconnected channels were formed in the catalyst shell. The properties of the catalyst are shown in Table 1.

[0037] Comparative Example 2 Same as Example 1, except that the flour in step (1) was not treated with alkali, but the same amount of alkali was sprayed in during the spherical forming in step (4) to obtain the hydrogenation demetallization catalyst cat6. Scanning electron microscopy revealed that no abundant micron-sized interconnected channels were formed in the catalyst shell. The properties of the catalyst are shown in Table 1.

[0038] Comparative Example 3 Same as Example 1, except that in step (1) sodium hydroxide was replaced with the same amount of ammonium bicarbonate to prepare the comparative hydrogenation demetallization catalyst cat7. Scanning electron microscopy revealed that no abundant micron-sized interconnected channels were formed in the catalyst shell. The catalyst properties are shown in Table 1.

[0039] Comparative Example 4 Same as Example 1, except that in step (2) the boehmite was not modified by active metal, but the same active metal was impregnated and loaded into the catalyst in step (6) to obtain the comparative hydrogenation demetallization catalyst cat8. The properties of the catalyst are shown in Table 1.

[0040] Table 1 Catalyst Properties Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 catalyst cat1 cat2 cat3 cat4 cat5 cat6 cat7 cat8 C content, wt% 25.3 29.6 32.5 22.1 25.6 25.9 25.7 25.6 <![CDATA[Al2O3 content, wt%]]> 63.9 59.9 57.3 67.5 63.7 63.2 63.7 63.6 <![CDATA[MoO3 content, wt%]]> 8.6 8.4 8.2 8.4 8.6 8.7 8.5 8.7 NiO content, wt% 2.2 2.1 2.0 2.0 2.1 2.2 2.0 2.1 δ1 0.38 0.57 0.24 0.69 0.38 0.41 0.39 0.96 δ2 1:3.3 1:2.8 1:2.1 1:3.6 1:3.4 1:3.2 1:3.3 1:3.5 The percentage of the area of ​​0.5-30μm pores in the shell, %. 85.6 83.9 87.2 86.2 ─ ─ ─ 86.8 The percentage of the area of ​​7.5-15μm pores in the shell, %. 62.6 66.1 65.3 63.1 ─ ─ ─ 63.5 As can be seen from Table 1, the hydrogenation catalyst shell prepared by the method of the present invention has a high content of micron-sized pores, and the active metal is distributed in the core-shell pattern in the radial direction of the catalyst.

[0041] Using a certain residual oil as feedstock, the feedstock oil contained 16.8 μg / g calcium, 13.3 μg / g iron, 89.6 μg / g nickel, and 51.5 μg / g vanadium. The catalytic performance of the catalysts cat1-cat8 in the above examples and comparative examples was evaluated using a 200 mL small-scale evaluation apparatus under the following reaction conditions: reaction temperature 385℃, pressure 15.0 MPa, and liquid hourly space velocity 0.3 h⁻¹. -1 The hydrogen-to-oil volume ratio was 900. After 500 hours of reaction, the content of various impurities in the generated oil was measured, and the impurity removal rate was calculated. The evaluation results are shown in Table 2. As the operating time increased, the catalyst activity decreased. In order to maintain the catalyst activity to meet production requirements, it is necessary to raise the temperature of the catalyst bed. The temperature rise of the catalyst bed after 3000 hours of operation is shown in Table 3.

[0042] Table 2 Comparison of Hydrodemetallization Performance of Catalysts Catalyst number cat1 cat2 cat3 cat4 cat5 cat6 cat7 cat8 Relative demetallization rate (Ca+Fe), % 129 128 124 118 100 103 98 135 Relative demetallization (V+Ni) rate, % 131 125 129 126 100 101 106 110 As can be seen from the data in Table 2, the catalyst prepared by the method of the present invention has a high ability to remove metallic impurities such as calcium, iron, nickel, and vanadium.

[0043] Table 3 shows the temperature rise of the catalyst bed after 3000 hours of operation.

[0044]

[0045] As can be seen from the results in Table 3, after 3000 hours of reaction, the catalyst prepared by the present invention has a lower temperature rise than the comparative catalyst, indicating that the catalyst prepared by the present invention has a strong long-term operation capability.

Claims

1. A hydrogenation catalyst, characterized in that: It includes a support and active metals, wherein the support is an alumina core wrapped in a carbon shell, and the active metals are Mo and Ni. Based on the weight of the catalyst, the content of MoO3 is 7.5wt%-15.5wt%, the content of NiO is 1.5wt%-4.5wt%, the carbon content is 20wt%-45wt%, and the alumina content is 35wt%-70wt%; the ratio δ1 of the shell active metal content to the core active metal content is 0.25:1-0.75:

1.

2. The catalyst according to claim 1, characterized in that: The ratio δ2 of the carbon shell thickness to the radius of the alumina core is 1:1 to 1:

4.

3. The catalyst according to claim 1, characterized in that: The carbon shell has internal pore sizes of 0.5-30μm, with pores of 0.5-30μm accounting for more than 80% of the area per unit area, and pores of 7.5-15μm accounting for more than 60% of the pores of 0.5-30μm.

4. A method for preparing a hydrogenation catalyst according to any one of claims 1 to 3, characterized in that... The process includes the following: (1) Mixing flour with inorganic alkali and grinding it to obtain pretreated flour, then adding nickel nitrate and ammonium heptamolybdate to the pretreated flour and mixing it to obtain active metal modified flour; (2) Impregnating boehmite with impregnation solution containing Mo and Ni, and drying the impregnated boehmite to obtain active metal modified boehmite; (3) Placing the active metal modified boehmite from step (2) in a rotary forming machine to form active metal modified boehmite microspheres; (4) Placing the active metal modified flour from step (1) and the active metal modified boehmite microspheres from step (3) in a rotary forming machine to form a hydrogenation catalyst precursor; (5) Placing the hydrogenation catalyst precursor from step (4) in a sealed container for heat treatment, and drying and calcining the treated material to obtain a hydrogenation catalyst.

5. The method according to claim 4, characterized in that: The flour mentioned in step (1) is wheat flour, with a protein content of 6%-20% and a starch content of 65%-75%.

6. The method according to claim 4, characterized in that: The inorganic alkali mentioned in step (1) is one or more of LiOH, KOH or NaOH, and the mass ratio of inorganic alkali to flour is 2:100-12:

100.

7. The method according to claim 4, characterized in that: The XRD pattern of the pretreated flour in step (1) shows that the peak intensity of the diffraction peaks at 2θ of 15º, 17º, 18º, and 23º is reduced by more than 60% compared with that of the flour raw material, preferably by 75%-90%; wherein the average grain size D corresponding to the peak position at 2θ of 15º is 6.5-8.5nm, D=Kλ / (Bcosθ), where K is the Scherrer constant, λ is the diffraction wavelength of the target material, B is the half-width of the diffraction peak, and θ is the diffraction angle.

8. The method according to claim 4, characterized in that: The ratio of the amount of nickel nitrate added in step (1) to the mass of the pretreated flour is 1:100-5:100; the ratio of the amount of ammonium heptamolybdate added to the mass of the flour is 1:100-8:

100.

9. The method according to claim 4, characterized in that: The impregnation solution containing Mo and Ni in step (2) is a phosphoric acid solution containing Mo and Ni. The Mo content in the solution is 5.5-10.5 g / 100 mL as MoO3, and the Ni content is 1.3-4.5 g / 100 mL as NiO. The amount of solution used is the saturated water absorption capacity of boehmite.

10. The method according to claim 4, characterized in that: The pseudoboehmite described in step (2) has a pore size of 10-30 nm.

11. The method according to claim 4, characterized in that: The operating conditions of the rotary forming machine in step (3) are as follows: the tilt angle of the rotary table is 40-70º, the rotation speed of the rotary table is 10-30 rpm; the forming time of the material in the rotary table is 45-120 min; during the ball forming process, an aqueous solution containing adhesive solvent is sprayed into the material; the aqueous solution containing adhesive solvent is one or more of the aqueous solutions of nitric acid, phosphoric acid, oxalic acid and acetic acid, and the mass concentration of the solution is 1%-3%.

12. The method according to claim 4, characterized in that: The operating conditions for the rotary forming machine in step (4) are as follows: the tilt angle of the rotary table is 40-70º, the rotation speed of the rotary table is 10-30rpm, and the forming time of the material in the rotary table is 30-45min.

13. The method according to claim 4, characterized in that: The sealed container in step (5) is a sealed high-pressure reactor. The volume of the hydrogenation catalyst precursor accounts for 30% to 70% of the volume of the sealed container. The heat treatment temperature is 40-90℃ and the treatment time is 60-120min.

14. The method according to claim 4, characterized in that: The drying temperature in step (5) is 120-180℃ and the drying time is 2-6 hours; the calcination conditions are: calcination temperature is 400-600℃ and the calcination time is 4-8 hours, and the calcination atmosphere is an inert atmosphere, which is one or more of argon, helium or nitrogen.

15. The application of a hydrotreating catalyst according to any one of claims 1 to 3 in the hydrotreating of heavy residue oil.

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