Eggshell type catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalysts, and discloses an eggshell type catalyst and a preparation method and application thereof, the preparation method comprises the following steps: (1) providing an impregnation liquid containing a hydrogenation active metal precursor and a binder; wherein the binder is selected from at least one of Arabic gum, guar gum and carrageenan; in the impregnation liquid, the weight concentration of the binder is 1-15g / 100mL; and (2) impregnating a catalyst carrier with the impregnation liquid, and then drying and roasting. The preparation method can effectively adjust the thickness of the shell layer on the surface of the eggshell type hydrogenation catalyst and the dispersity of the active metal while ensuring the metal feeding amount, and improves the pore volume and the specific surface area of the catalyst, thereby improving the activity of the catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and particularly relates to an eggshell-type catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Most of the impurities such as metals (e.g., V, Fe), sulfur, and nitrogen in residue oil mainly exist in macromolecular compounds such as resins and asphaltenes. These compounds have complex structures and large molecular sizes, and it is difficult to diffuse in the catalyst pores. Moreover, after the metal is removed, it will deposit on the catalyst surface and in the pores, resulting in low utilization rate of the active metal and waste of the active metal. By loading the active metal component on the surface layer of the carrier to prepare an eggshell-type catalyst, the activity of the catalyst can be effectively improved, and the amount of the active metal used can be reduced, thereby reducing the production cost of the catalyst.

[0003] CN101143325A discloses a catalyst preparation method. First, a soluble compound containing the component to be loaded is prepared, and then the prepared solution is sprayed onto a rolling carrier or a carrier pre-loaded with an active metal component while the carrier is heated during the spraying process; the obtained product is dried or calcined; by repeatedly spraying and drying the carrier, a catalyst with an obvious shell-type distribution can be obtained. This method has complex processes and is cumbersome. CN113000055A discloses a preparation method of a shell-layer type hydrogenation catalyst, which utilizes the colloidal solubility of pseudo-boehmite and the correlation of the distribution of the active metal component on the carrier surface to prepare a catalyst with the active metal component distributed in a shell layer, but this preparation method is greatly affected by the carrier and has a narrow application range. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems in the prior art that it is difficult to control the distribution of the active metal component in the catalyst, the activity of the catalyst is insufficient, and the cost is high, and to provide an eggshell-type catalyst, a preparation method thereof, and an application thereof. The preparation method can effectively adjust the concentration of the active metal on the catalyst surface, and the catalyst has good activity.

[0005] To achieve the above purpose, the first aspect of the present invention provides a preparation method of an eggshell-type catalyst, comprising the following steps:

[0006] (1) Providing an impregnating solution containing a precursor of a hydrogenation active metal and a binder;

[0007] Wherein, the binder is selected from at least one of gum arabic, guar gum, and carrageenan; in the impregnating solution, the weight concentration of the binder is 1-15 g / 100 mL;

[0008] (2) Impregnating a catalyst carrier with the above impregnating solution, and then drying and calcining.

[0009] The second aspect of the present invention provides an eggshell-type catalyst prepared by the above preparation method; the catalyst includes a carrier and a hydrogenation active metal component supported on the carrier; in the catalyst, the shell factor α of the hydrogenation active metal component is 0.8-0.95.

[0010] The third aspect of the present invention provides the application of the above eggshell-type catalyst in residue hydrogenation.

[0011] Through the above technical solution, by introducing a binder during the preparation of the active metal impregnation solution, the viscosity of the solution can be well controlled, and the obtained active metal impregnation solution is very stable, which can effectively adjust the thickness of the surface shell layer of the eggshell-type hydrogenation catalyst and the dispersion degree of the active metal, and at the same time can also stabilize the active metal component on the hydrogenation catalyst and reduce the loss of the metal component. Moreover, the eggshell-type catalyst prepared by this method distributes the active metal on the surface layer of the catalyst, making the catalyst have a larger pore volume and specific surface area, which helps to shorten the diffusion distance of the reactant molecules to the active center. Specific Embodiments

[0012] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0013] The first aspect of the present invention provides a preparation method of an eggshell-type catalyst, including the following steps:

[0014] (1) Provide an impregnation solution containing a precursor of a hydrogenation active metal and a binder;

[0015] Wherein, the binder is selected from at least one of arabic gum, guar gum and carrageenan; in the impregnation solution, the weight concentration of the binder is 1-15 g / 100 mL;

[0016] (2) Impregnate the catalyst carrier with the above impregnation solution, and then carry out drying and calcination.

[0017] According to the present invention, by introducing a binder during the preparation of the impregnation solution, by adjusting the concentration of the binder, the thickness of the surface shell layer of the eggshell-type hydrogenation catalyst and the dispersion degree of the active metal can be effectively adjusted, and at the same time the active metal component on the hydrogenation catalyst can be stabilized, reducing the loss of the metal component. The eggshell-type catalyst prepared by this method distributes the active metal on the surface layer of the catalyst, which is beneficial to obtaining a larger pore volume and specific surface area, shortening the diffusion distance of the reactant molecules to the active center, and thus improving the catalyst activity.

[0018] According to the present invention, controlling the concentration of the binder in the impregnating solution within the above range, the impregnating solution has an appropriate viscosity, which can effectively regulate the distribution of the hydrogenation metal on the surface of the eggshell-type hydrogenation catalyst, and is also beneficial to improving the stability of the impregnating solution and reducing the loss of the hydrogenation active metal component. Preferably, in the impregnating solution, the weight concentration of the binder is 5-15 g / 100 mL, for example, it can be specific but non-limiting weight concentrations such as 5 g / 100 mL, 6 g / 100 mL, 7 g / 100 mL, 8 g / 100 mL, 9 g / 100 mL, 10 g / 100 mL, 11 g / 100 mL, 12 g / 100 mL, 13 g / 100 mL, 14 g / 100 mL, 15 g / 100 mL or the range between any two of them.

[0019] According to the present invention, the binder is selected from any one of gum arabic, guar gum and carrageenan. A single binder can be used, or a combination of two or three binders can be used. The present invention has no special limitation on this, as long as the concentration requirement of the above binder is met.

[0020] According to some preferred embodiments of the present invention, the binder is gum arabic. In the above preferred case, it is beneficial to further improve the stability of the impregnating solution, obtain an appropriate enrichment amount on the outer surface while ensuring the metal loading amount, contribute to stabilizing the active metal component on the hydrogenation catalyst, and reduce the loss of the metal component.

[0021] The present invention has no special limitation on the source of the binder, and it can be obtained through commercial purchase.

[0022] In the present invention, the "hydrogenation active metal" can be any metal element having hydrogenation activity, which is well known to those skilled in the art. The present invention has no special limitation on the specific type of the hydrogenation active metal, and conventional metals with hydrogenation functions in the art can be applied to the present invention, for example, it can be a transition metal.

[0023] According to some preferred embodiments of the present invention, the hydrogenation active metal is selected from at least one of Group VIB metals and Group VIII metals, preferably at least one of Mo, W, Ni and Co.

[0024] Preferably, the amount of the precursor of the hydrogenation active metal is such that the content of the hydrogenation active metal in the prepared catalyst, calculated as the oxide, is 4-25 wt%, preferably 4-12 wt%.

[0025] Preferably, in the impregnation solution, the weight concentration of the precursor of the hydrogenation active metal in terms of oxide is 20-150 g / 100 mL, preferably 50-80 g / 100 mL. By adopting the above preferred embodiment, it can not only ensure the loading of the hydrogenation active metal, but also be beneficial to adjusting the relative concentration of the active metal on the catalyst surface.

[0026] The present invention does not particularly limit the specific type of the precursor of the hydrogenation active metal, and it can be a conventional compound containing a hydrogenation active metal element in the art. For example, the precursor of molybdenum can be ammonium molybdate and / or molybdenum nitrate; the precursor of tungsten can be at least one of ammonium metatungstate, tungsten nitrate and tungstic acid; the precursor of nickel can be at least one of nickel nitrate, nickel sulfate, nickel chloride, basic nickel carbonate and nickel carbonate; the precursor of cobalt can be at least one of cobalt oxide, cobalt nitrate, basic cobalt carbonate and cobalt chloride.

[0027] The precursor of the hydrogenation active metal may also contain crystal water, which will not be elaborated here.

[0028] In order to further improve the hydrogenation activity of the catalyst, in a further preferred embodiment, the hydrogenation active metal includes a first metal component and a second metal component, the first metal component is Mo and / or W, and the second metal component is Ni and / or Co. Through the synergistic effect of the first metal component and the second metal component, it is beneficial to further improve the hydrogenation activity of the catalyst.

[0029] According to some preferred embodiments of the present invention, in terms of oxide, the mass ratio of the first metal component to the second metal component is 2-5:1, preferably 3-4.5:1.

[0030] Preferably, the dosage of the precursor of the hydrogenation active metal is such that in the prepared catalyst, in terms of oxide, the content of the first metal component is 4-20 wt%, preferably 4-10 wt%, and the content of the second metal component is 0.5-5 wt%, preferably 0.8-2 wt%.

[0031] According to some preferred embodiments of the present invention, the impregnation solution further contains a phosphorus source. In the above case, it is beneficial to ensure the loading of the hydrogenation active metal.

[0032] Preferably, the dosage of the phosphorus source is such that in the prepared catalyst, the content of phosphorus element in terms of phosphorus pentoxide is 1-5 wt%.

[0033] Preferably, the impregnation solution further contains a solvent. The present invention has no special requirements for the type of the solvent in the impregnation solution, as long as it can fully dissolve each component. Preferably, the solvent is water.

[0034] The present invention has no particular requirements for the specific manner of providing the impregnating solution, as long as a uniform and flowable impregnating solution can be formed. According to some preferred embodiments of the present invention, the method for providing the impregnating solution in step (1) includes: dispersing a precursor of a hydrogenation active metal in a solvent, stirring at 70 - 120 °C for 0.5 - 3 h, then cooling to 30 - 60 °C, and adding the binder and stirring for 0.5 - 1 h. Adopting the above preferred embodiments is beneficial to exert the viscosity control effect of the binder, improve the stability of the impregnating solution, and further adjust the thickness of the surface shell layer of the eggshell-type hydrogenation catalyst and the dispersion degree of the active metal.

[0035] The present invention has no particular limitations on the specific operation methods and conditions of the impregnation in step (2), and conventional impregnation methods in the art can be adopted. For example, the spray impregnation method can be used. The present invention also has no particular requirements for the equipment of the impregnation. For example, it can be carried out in a double-cone impregnating machine.

[0036] In the present invention, the impregnation process can be carried out by single impregnation or stepwise impregnation.

[0037] According to some preferred embodiments of the present invention, the impregnation process includes: first bringing at least part of the impregnating solution into first contact with the catalyst support, and then bringing the remaining part of the impregnating solution into second contact with the catalyst support. Adopting the above preferred embodiments is beneficial to further increase the concentration of the active metal on the outer surface of the catalyst on the basis of ensuring the total amount of the active metal loaded, thereby improving the utilization rate of the active metal and the hydrogenation activity of the catalyst.

[0038] Preferably, based on the total volume of the impregnating solution, the volume content of the at least part of the impregnating solution is 5 - 20%.

[0039] Preferably, the conditions for the first contact include: temperature of 10 - 40 °C and time of 0.5 - 2 h, and the conditions for the second contact include: temperature of 10 - 40 °C and time of 0.5 - 2 h.

[0040] Preferably, the drying temperature is 80 - 130 °C and the time is 2 - 10 h.

[0041] Preferably, the calcination temperature is 350 - 650 °C and the time is 3 - 5 h.

[0042] In the present invention, there is no particular selection for the composition of the catalyst support, and conventional shaped supports for hydrogenation catalysts in the art can be applied to the present invention.

[0043] According to some preferred embodiments of the present invention, the method for preparing the catalyst support includes: mixing an alumina precursor, an adhesive, and an optional auxiliary agent, shaping the mixture, and then performing shaping drying and shaping calcination.

[0044] Preferably, the alumina precursor is selected from at least one of alumina powder, silica-alumina powder, and silica-alumina molecular sieve. The molar ratio of silica to alumina in the silica-alumina powder is 5-50:1.

[0045] According to some preferred embodiments of the present invention, the alumina precursor is alumina powder and silica-alumina powder, and the mass ratio of the alumina powder to the silica-alumina powder is 1-5:1.

[0046] The present invention has a wide selection range for the adhesive. For example, it can be an acidic aqueous solution. In the acidic aqueous solution, the total content of inorganic acid and / or inorganic acid is 2-10 wt%. The inorganic acid can be selected from at least one of nitric acid, phosphoric acid, sulfuric acid, and hydrochloric acid, preferably nitric acid; the organic acid can be selected from at least one of acetic acid, citric acid, and oxalic acid.

[0047] Preferably, based on 100 parts by weight of the alumina precursor, the amount of the adhesive used is 50-150 parts by weight.

[0048] In the present invention, the auxiliary agent can be added according to actual needs, such as a pore-expanding agent and / or an extrusion aid. The present invention has no particular limitation on the specific selection of the pore-expanding agent and the extrusion aid, and can be a conventional selection in the art. For example, the pore-expanding agent can be selected from at least one of carbon black, ammonium carbonate, and polyvinyl alcohol. The extrusion aid can be talc powder and / or polyethylene glycol.

[0049] According to some preferred embodiments of the present invention, based on 100 parts by weight of the alumina precursor, the amount of the auxiliary agent used is 0-5 parts by weight.

[0050] In the present invention, the shaping can be carried out by using a conventional shaping method in the art. For example, the alumina precursor, the adhesive, and the auxiliary agent can be kneaded and mixed and then shaped. The shaping method can be extrusion shaping.

[0051] Preferably, the temperature of the shaping drying is 70-130 °C, and the time is 1-10 h.

[0052] Preferably, the temperature of the shaping calcination is 450-850 °C, and the time is 4-8 h.

[0053] The second aspect of the present invention provides an eggshell-type catalyst prepared by the above preparation method. The catalyst includes a support and a hydrogenation active metal component supported on the support; in the catalyst, the shell layer factor α of the hydrogenation active metal component is 0.8-0.95.

[0054] In the present invention, the shell factor α is the ratio of the concentration of the hydrogenation active metal component at the center of the catalyst particle to the concentration on the outer surface. The α value represents the distribution form of the active component on the catalyst and quantitatively describes the degree of non-uniform distribution. The concentration of the hydrogenation active metal component on the outer surface of the catalyst refers to the average value of the concentration test results of 20 numerical points near the outer surface along the radial direction of the catalyst in the SEM-EDS characterization result; the concentration of the hydrogenation active metal component at the center of the catalyst particle refers to the average value of the concentration test results of 20 numerical points near the center point of the catalyst in the SEM-EDS characterization result.

[0055] Preferably, the specific surface area of the eggshell-type catalyst is 185 - 200 m 2 / g, preferably 190 - 195 m 2 / g.

[0056] Preferably, the pore volume of the eggshell-type catalyst is 0.44 - 0.55 mL / g, preferably 0.45 - 0.5 mL / g.

[0057] In the present invention, the specific surface area and pore volume are measured using the ASAP2400 physical and chemical adsorption instrument of the American company Micro meritics, and the pore volume and specific surface area are measured using the BET method.

[0058] The third aspect of the present invention provides the application of the above-mentioned eggshell-type catalyst in residue hydrogenation.

[0059] In the above catalyst, the active metal is distributed on the surface layer of the catalyst. The catalyst has a larger pore volume and specific surface area, which helps to shorten the distance for reactant molecules to diffuse to the active center during the residue hydrogenation process. It has a higher hydrogenation activity.

[0060] The present invention will be described in detail below through examples.

[0061] Support preparation: At 25°C, an acidic aqueous solution (nitric acid weight content is 3%) is prepared. The aqueous solution is stirred for 1 h and then left to stand for half an hour before use. According to 100 parts by weight of alumina powder, 120 parts by weight of a nitric acid aqueous solution with a concentration of 0.3 wt% is added, and they are fully kneaded in a powder-liquid mixer. The kneaded material is extruded through a 1.9 mm cylindrical orifice plate after rolling for 25 min, dried at 80°C for 2.5 h, and then calcined at 600°C for 5 h. The obtained support is denoted as D.

[0062] Example 1

[0063] At room temperature, mix 70 L of water with 5 kg of phosphoric acid and stir for 3 - 5 minutes. Then add 50 kg of molybdenum trioxide, slowly add 20 kg of nickel basic carbonate. After adding all the materials, stir for 20 minutes and then start heating. After heating to 50 °C, keep the temperature constant for 40 minutes, then continue heating to 90 °C, keep the temperature constant for 60 minutes, then stop heating. After cooling to room temperature, add 5 kg of gum arabic, make up the water to a final volume of 100 L, stir for 30 minutes, filter the insoluble substances and reserve for use.

[0064] Add 100 kg of carrier D to the double - cone impregnation, then pre - spray 10 L of solution and stop the liquid inlet, start the double - cone rotation and homogenize for 5 minutes; the second liquid inlet is 90 L, and continue to rotate and homogenize for 40 minutes. The homogenized wet material is dried in air at 80 °C for 2 h and calcined at 650 °C for 3.5 h to obtain catalyst Z1. The test results are shown in Table 1.

[0065] Comparative Example 1

[0066] At room temperature, mix 70 L of water with 5 kg of phosphoric acid and stir for 3 - 5 minutes. Then add 50 kg of molybdenum trioxide, slowly add 20 kg of nickel basic carbonate. After adding all the materials, stir for 20 minutes and then start heating. After heating to 50 °C, keep the temperature constant for 40 minutes, then continue heating to 90 °C, keep the temperature constant for 60 minutes, then stop heating. After cooling to room temperature, make up the water to a final volume of 100 L, stir for more than 30 minutes and filter for reserve.

[0067] Add 100 kg of carrier D to the double - cone impregnation, then pre - spray 10 L of solution and stop the liquid inlet, start the double - cone rotation and homogenize for 5 minutes; the second liquid inlet is 90 L, and continue to rotate and homogenize for 40 minutes. The homogenized wet material is dried in air at 80 °C for 2 h and calcined at 650 °C for 3.5 h to obtain catalyst DZ1. The test results are shown in Table 1.

[0068] Example 2

[0069] At room temperature, mix 70 L of water with 5 kg of phosphoric acid and stir for 3 - 5 minutes. Then add 50 kg of molybdenum trioxide, slowly add 20 kg of nickel basic carbonate. After adding all the materials, stir for 20 minutes and then start heating. After heating to 50 °C, keep the temperature constant for 40 minutes, then continue heating to 90 °C, keep the temperature constant for 60 minutes, then stop heating. After cooling to room temperature, add 10 kg of gum arabic, make up the water to a final volume of 100 L, stir for 30 minutes, filter the insoluble substances and reserve for use.

[0070] Add 100 kg of carrier D to the double - cone impregnation, then pre - spray 10 L of solution and stop the liquid inlet, start the double - cone rotation and homogenize for 5 minutes; the second liquid inlet is 90 L, and continue to rotate and homogenize for 40 minutes. The homogenized wet material is dried in air at 80 °C for 2 h and calcined at 650 °C for 3.5 h to obtain catalyst Z2. The test results are shown in Table 1.

[0071] Example 3

[0072] At room temperature, 70 L of water is mixed with 5 kg of phosphoric acid and stirred for 3 - 5 minutes. Then 50 kg of molybdenum trioxide is added, and 20 kg of nickel basic carbonate is slowly added. After adding all the materials, it is stirred for 20 minutes and then heated. After heating to 50 °C, it is kept at a constant temperature for 40 minutes and then heated to 90 °C. After keeping at a constant temperature for 60 minutes, the heating is stopped. After cooling to room temperature, 15 kg of gum arabic is added, and water is added to make the final volume 100 L. It is stirred for more than 30 minutes, and the insoluble matter is filtered and reserved for use.

[0073] 100 kg of carrier D is added to a double - cone impregnator. Then 10 L of solution is pre - sprayed and the liquid inlet is stopped. The double - cone is started to rotate and homogenize for 5 minutes. The second liquid inlet is 90 L, and it continues to rotate and homogenize for 40 minutes. The homogenized wet material is dried in air at 80 °C for 2 h and calcined at 650 °C for 3.5 h to obtain catalyst Z3. The test results are shown in Table 1.

[0074] Example 4

[0075] According to the method of Example 2, the difference is that an equal mass of guar gum is used to replace gum arabic. The prepared catalyst is denoted as Z4. The test results are shown in Table 1.

[0076] Example 5

[0077] According to the method of Example 1, the difference is that 100 kg of carrier D is added to a double - cone impregnator, 100 L of solution is fed, the double - cone is started to rotate and homogenize for 45 minutes. The homogenized wet material is dried in air at 80 °C for 2 h and calcined at 650 °C for 3.5 h to obtain catalyst Z5. The test results are shown in Table 1.

[0078] Comparative Example 2

[0079] According to the method of Example 1, the difference is that the addition amount of the binder is 40 kg. The prepared catalyst is denoted as DZ2. The test results are shown in Table 1.

[0080] Table 1

[0081] Catalyst number Z1 Z2 Z3 Z4 Z5 DZ1 DZ2 <![CDATA[Specific surface area, m 2 / g]]> 190 193 186 190 188 182 192 Pore volume, mL / g 0.45 0.48 0.44 0.45 0.44 0.43 0.42 <![CDATA[MoO 3 , wt%]]> 9.49 9.52 9.48 9.45 9.46 9.5 9.10 NiO, wt% 2.35 2.37 2.34 2.32 2.32 2.36 1.88 <![CDATA[P 2 O 5 , wt%]]> 0.9 0.89 0.91 0.88 0.89 0.92 0.75 <![CDATA[α Mo > 0.94 0.85 0.90 0.89 0.96 0.98 0.78 <![CDATA[α Ni > 0.92 0.88 0.91 0.90 0.94 0.99 0.75

[0082] It can be seen from the results in Table 1 that by comparing Example 1 and Comparative Example 1, for the catalyst in which the active components form metal compounds with an egg - shell - type distribution on the carrier in the example, the proportion of the hydrogenation active metal components entering the center of the catalyst particles is lower. The catalyst has a higher specific surface area and a larger pore volume, which helps to shorten the diffusion distance of reactant molecules to the active center during the residue oil hydrogenation process. Compared with the comparative example, the catalyst prepared in the example has a higher hydrogenation activity.

[0083] It can be seen from the comparison between Example 1 and Comparative Example 2 that when the concentration of the binder is too high, the metal loading is low, which is not conducive to improving the utilization rate of the hydrogenation metal. By using an appropriate concentration of the binder in the present invention, the metal concentration on the outer surface of the eggshell-type hydrogenation catalyst can be effectively adjusted and a relatively high metal loading can be achieved at the same time.

[0084] It can be seen from the comparison between Example 1 and Example 5 that stepwise impregnation of the carrier with the impregnation solution is beneficial to further increase the concentration of the active metal on the outer surface of the catalyst on the basis of ensuring the total active metal loading, thereby improving the utilization rate of the active metal and the hydrogenation activity of the catalyst.

[0085] It can be seen therefrom that the method provided by the present invention can be used to achieve an eggshell distribution of the active components on the carrier, with simple operation and little environmental pollution.

[0086] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A preparation method of an eggshell-type catalyst, characterized in that, it comprises the following steps: (1) Provide an impregnation solution containing a precursor of a hydrogenation active metal and a binder; wherein, the binder is selected from at least one of gum arabic, guar gum and carrageenan; in the impregnation solution, the weight concentration of the binder is 1-15 g / 100 mL; (2) Impregnate a catalyst support with the above impregnation solution, and then perform drying and calcination.

2. The preparation method according to claim 1, wherein, in the impregnation solution, the weight concentration of the binder is 5-15 g / 100 mL; preferably, the binder is gum arabic.

3. The preparation method according to claim 1 or 2, wherein, the hydrogenation active metal is selected from at least one of Group VIB metals and Group VIII metals, preferably at least one of Mo, W, Ni and Co; preferably, the dosage of the precursor of the hydrogenation active metal is such that in the prepared catalyst, the content of the hydrogenation active metal in terms of oxide is 4-25 wt%, preferably 4-12 wt%; preferably, in the impregnation solution, the weight concentration of the precursor of the hydrogenation active metal in terms of oxide is 20-150 g / 100 mL.

4. The preparation method according to claim 3, wherein, the hydrogenation active metal comprises a first metal component and a second metal component, the first metal component is Mo and / or W, and the second metal component is Ni and / or Co; preferably, in terms of oxide, the mass ratio of the first metal component to the second metal component is 2-5:1; preferably, the dosage of the precursor of the hydrogenation active metal is such that in the prepared catalyst, in terms of oxide, the content of the first metal component is 4-20 wt%, preferably 4-10 wt%, and the content of the second metal component is 0.5-5 wt%, preferably 0.8-2 wt%.

5. The preparation method according to any one of claims 1-4, wherein, the impregnation solution further contains a phosphorus source; preferably, the dosage of the phosphorus source is such that in the prepared catalyst, the content of phosphorus element in terms of phosphorus pentoxide is 1-5 wt%.

6. The preparation method according to any one of claims 1-5, wherein, the method for providing the impregnation solution in step (1) includes: dispersing the precursor of the hydrogenation active metal in a solvent, stirring at 70-120 °C for 0.5-3 h, then cooling to 30-60 °C, and adding the binder and stirring for 0.5-1 h.

7. The preparation method according to any one of claims 1-6, wherein, the impregnation process includes: first making a first contact between at least part of the impregnation solution and the catalyst support, and then making a second contact between the remaining part of the impregnation solution and the catalyst support; preferably, based on the total volume of the impregnation solution, the volume content of the at least part of the impregnation solution is 5-20%. preferably, the conditions for the first contact include: temperature of 10-40 °C, time of 0.5-2 h, and the conditions for the second contact include: temperature of 10-40 °C, time of 0.5-2 h; Preferably, the drying temperature is 80 - 130 °C and the time is 2 - 10 h; Preferably, the calcination temperature is 350 - 650 °C and the time is 3 - 5 h.

8. The preparation method according to any one of claims 1 - 7, wherein, the preparation method of the catalyst support includes: mixing an alumina precursor, an adhesive and an optional auxiliary agent, shaping, and then performing shaping drying and shaping calcination; Preferably, the alumina precursor is selected from at least one of alumina powder, silica-alumina powder and silica-alumina molecular sieve; Preferably, based on 100 parts by weight of the alumina precursor, the amount of the adhesive is 50 - 150 parts by weight, and the amount of the auxiliary agent is 0 - 5 parts by weight; Preferably, the shaping drying temperature is 70 - 130 °C and the time is 1 - 10 h; Preferably, the shaping calcination temperature is 450 - 850 °C and the time is 4 - 8 h.

9. An eggshell-type catalyst prepared by the preparation method according to any one of claims 1 - 8; the catalyst includes a support and a hydrogenation active metal component supported on the support; in the catalyst, the shell layer factor α of the hydrogenation active metal component is 0.8 - 0.

95.

10. Use of the eggshell-type catalyst according to claim 9 in residue oil hydrogenation.