Residue oil hydrodesulfurization catalyst and preparation method thereof

Abstract

The invention discloses a residual oil hydrodesulfurization catalyst and a preparation method thereof. The catalyst comprises a matrix inner layer composed of a carrier and a first active metal component loaded on the carrier and a catalyst outer layer composed of a macroporous alumina layer and a second active metal component, wherein the first active metal component and the second active metal component both comprise metal molybdenum and nickel; the thickness of the macroporous alumina layer is 20 to 400 μm, and the content ratio of tetrahedral molybdenum to octahedral molybdenum in the catalyst is 0.10 to 0.50 in terms of Mo atoms. The catalyst has a strong anti-carbon deposition ability, and when used in the residual oil hydrodesulfurization reaction, it can improve the hydrodesulfurization activity of the catalyst and prolong the operation time of the device.

Description

Technical Field

[0001] The invention relates to a hydrogenation catalyst and a preparation method thereof, and in particular to a residual oil hydrodesulfurization catalyst and a preparation method thereof. Background Art

[0002] As the world's crude oil becomes heavier and inferior, the lightening of heavy oil and the efficient treatment of heavy oil are becoming more and more common concerns of today's refineries. In the application process of fixed-bed residue oil hydrogenation technology, its catalyst grading system can effectively remove impurities such as metals, sulfur, nitrogen and carbon residue from residue oil, and has good industrial application effect. However, in order to further improve the economic benefits of refineries, the proportion of inferior residue oil in the raw materials will be continuously increased in the residue oil hydrogenation unit, which puts higher requirements on residue oil hydrogenation catalysts. In addition, with increasingly stringent environmental protection standards, the performance requirements for residue oil hydrodesulfurization catalysts are also higher.

[0003] At present, due to the worsening deterioration of feed in residue oil hydrotreating units, a large amount of aromatic condensed ring compounds in the raw materials are deposited on the catalyst, forming carbon-rich organic deposits that block the pores, cover the active centers of the catalyst, affect the catalyst activity, and cause the bed pressure drop to gradually increase, thus affecting the operation cycle of the unit.

[0004] CN101618326A discloses a heavy oil hydroprocessing catalyst and a preparation method thereof. The catalyst comprises a carrier, at least one metal component selected from group VIII and at least one metal component selected from group VIB. The pore volume of the carrier is 0.6-1.2 ml / g, and the specific surface area is 200-380 m 2 / g, an average pore diameter of 11-14nm, and pores with a pore diameter of 9nm-15nm account for 80-95% of the total pore volume. The preparation method of the carrier includes forming, drying and calcining the alumina precursor, wherein the calcination conditions are calcining at a temperature of 350-400°C for 0.5-2h and then calcining at a temperature of 600-800°C for 1-6h.

[0005] CN110201691A discloses a residual oil hydrodemetallization desulfurization catalyst and a preparation method thereof, wherein two pseudo-boehmite with different crystal sizes are used as precursors to prepare an alumina carrier, and at least one VIB group metal component and at least one VIII group metal component are used to form a hydrogenation active metal component to prepare the residual oil hydrodemetallization desulfurization catalyst, the pore volume of the catalyst is 0.4-0.8 mL / g, and the specific surface area is 100-200 m 2 / g, the average mesopore diameter is 12-20nm, and it can be used for hydrodemetallization and desulfurization of heavy oils such as residual oil.

[0006] In summary, as the deterioration of feed in the residue oil hydroprocessing unit worsens, the catalysts prepared by the existing technology have failed to effectively improve the problem of carbon deposition on the catalyst surface, and the hydrodesulfurization activity and stability still need to be further improved. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention provides a residual oil hydrodesulfurization catalyst and a preparation method thereof. The catalyst has strong anti-carbon deposition ability and can improve the hydrodesulfurization activity of the catalyst and prolong the operation time of the device when used in the residual oil hydrodesulfurization reaction.

[0008] On the one hand, the present invention provides a residual oil hydrodesulfurization catalyst, comprising a matrix inner layer composed of a carrier and a first active metal component loaded on the carrier, and a catalyst outer layer composed of a macroporous alumina layer and a second active metal component, wherein the first active metal component and the second active metal component both include metal molybdenum and nickel; the thickness of the macroporous alumina layer is 20 to 400 μm, preferably 50 to 180 μm, and further preferably 85 to 105 μm; wherein, in the catalyst, the content ratio of tetrahedral molybdenum to octahedral molybdenum, calculated as Mo atoms, is 0.10 to 0.50.

[0009] In the present invention, the carrier may be an alumina-based carrier. The pore volume of the carrier is 0.60 to 0.90 cm 3 / g, specific surface area is 170~340m 2 / g.

[0010] In the present invention, the pore volume of the macroporous alumina layer is 0.85 to 1.00 cm 3 / g, the pore volume with a pore diameter of 50-180 nm accounts for 20%-60% of the total pore volume.

[0011] In the present invention, preferably, the macroporous alumina layer comprises one or more additives selected from fluorine, phosphorus, silicon or boron, and the content of the additives in terms of oxide is 2.0% to 20.0% based on the mass of alumina in the macroporous alumina layer.

[0012] In the present invention, in the catalyst, based on the mass of the catalyst, the content of molybdenum oxide is 5.0% to 25.0%, and the content of nickel oxide is 2.0% to 10.0%.

[0013] In the present invention, based on the mass of total molybdenum oxide in the catalyst, the content of molybdenum oxide in the first active metal component is 30% to 65%, and the content of molybdenum oxide in the second active metal component is 35% to 70%.

[0014] In the present invention, based on the mass of total nickel oxide in the catalyst, the content of nickel oxide in the first active metal component is 30% to 65%, and the content of nickel oxide in the second active metal component is 35% to 70%.

[0015] The second aspect of the present invention provides a method for preparing the above-mentioned residue hydrodesulfurization catalyst, comprising the following steps:

[0016] (1) spraying a first active metal impregnation solution onto a carrier in an unsaturated impregnation manner, followed by drying and a first calcination to obtain a catalyst intermediate A;

[0017] (2) adding the intermediate A obtained in step (1) into the macroporous pseudo-boehmite gel, stirring and soaking, taking out after the surface is coated with the gel, drying, and second calcining to obtain the intermediate B;

[0018] (3) Spraying the second active metal impregnation solution onto the intermediate B obtained in step (2) in a saturated impregnation manner, and obtaining the residual oil hydrodesulfurization catalyst after drying and a third calcination.

[0019] In the method of the present invention, the carrier in step (1) may be an alumina-based carrier, and the pore volume of the carrier is 0.60 to 0.90 cm 3 / g, specific surface area is 170~340m 2 / g.

[0020] In the method of the present invention, the active metals in the first active metal impregnation solution in step (1) are preferably molybdenum and nickel. The content of MoO3 in the first active metal impregnation solution is 15.0-55.0 g / 100 ml, and the content of NiO is 5.0-15.0 g / 100 ml. Among them, the mass of molybdenum oxide introduced into the catalyst by the first active metal impregnation solution accounts for 30%-65% of the total molybdenum oxide loading in the catalyst, and the mass of nickel oxide introduced into the catalyst by the first active metal impregnation solution accounts for 30%-65% of the total nickel oxide loading in the catalyst.

[0021] In the method of the present invention, the amount of the first impregnation liquid used in step (1) is 20% to 50% of the saturated water absorption rate of the carrier.

[0022] In the method of the present invention, the drying condition in step (1) is drying at 120-180° C. for 2-12 hours.

[0023] In the method of the present invention, the first calcination condition in step (1) is calcination at 550-650° C. for 2-6 hours, and the calcination atmosphere is one or more of air, water vapor, and nitrogen, preferably air.

[0024] In the method of the present invention, before the catalyst intermediate A described in step (2) is added to the macroporous pseudo-boehmite gel, the catalyst body is preferably soaked in a binder solution. The binder content in the binder solution is 3% to 45%, preferably 3% to 30%. The binder solution is composed of a binder and pure water.

[0025] In the method of the present invention, the binder in step (2) can be one or more of starch, dextrin, polyvinyl alcohol or carboxymethyl cellulose. Preferably, the catalyst intermediate A is immersed in the binder solution for 0.3 to 5 minutes, and the excess binder solution is drained off and left at room temperature for 10 to 80 minutes.

[0026] The concentration of aluminum oxide in the macroporous pseudo-boehmite gel is 15 g / L to 60 g / L, preferably 18 g / L to 55 g / L. The macroporous pseudo-boehmite gel preferably contains one or more of fluorine, phosphorus, silicon or boron as an auxiliary agent; based on the mass of aluminum oxide, the amount of the auxiliary agent (calculated as an element) added is 2.0% to 20% of the mass of aluminum oxide.

[0027] In the method of the present invention, the drying condition in step (2) is drying at 120-180° C. for 2-12 hours.

[0028] In the method of the present invention, the second calcination condition in step (2) is: calcining at a temperature of 450 to 650° C. for 2 to 8 hours to convert into a macroporous alumina outer layer. The macroporous pseudo-boehmite gel can be obtained by the following method: using an inorganic aluminum source as a raw material, without adding a template, adjusting the pH value to 2.5 to 3.5, and performing a hydrothermal treatment at 180 to 320° C. for 3.0 to 6.0 hours. The inorganic aluminum source can be selected from at least one of aluminum sulfate, aluminum nitrate, and aluminum chloride.

[0029] In the method of the present invention, the catalyst intermediate A in step (2) is added to the macroporous pseudo-boehmite gel and stirred for 0.5 to 20 minutes. After the surface is coated with gel, it is taken out and centrifuged to remove excess gel on the surface for 1 to 10 minutes. Then, it is dried at 120 to 180° C. for 2 to 12 hours. Then, it is calcined at 450 to 650° C. for 2 to 8 hours. The thickness of the outer layer of aluminum oxide can be controlled by controlling the concentration of aluminum oxide in the macroporous pseudo-boehmite gel, the soaking time and the centrifugation time.

[0030] In the method of the present invention, the active metals in the second active metal impregnation solution in step (3) are preferably molybdenum and nickel. The content of MoO3 in the second active metal impregnation solution is 2.0-40.0 g / 100 ml, and the content of NiO is 1.0-18.0 g / 100 ml. Among them, the mass of molybdenum oxide introduced into the catalyst by the second active metal impregnation solution accounts for 35%-70% of the total molybdenum oxide loading in the catalyst, and the mass of nickel oxide introduced into the catalyst by the second active metal impregnation solution accounts for 35%-70% of the total nickel oxide loading in the catalyst.

[0031] In the method of the present invention, the third calcination in step (3) adopts programmed temperature increase, the heating rate is 1°C / min to 3°C / min, the third calcination temperature is 450 to 600°C, the calcination time is 3 to 6 hours, and the calcination atmosphere is one or more of air, water vapor, and nitrogen, preferably air.

[0032] In the method of the present invention, the temperature of the third calcination is 50-200° C. lower than the temperature of the first calcination.

[0033] The third aspect of the present invention provides the use of the above-mentioned residue oil hydrodesulfurization catalyst in a residue oil hydrotreating process.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The residual oil hydrodesulfurization catalyst of the present invention comprises a matrix inner layer composed of a carrier and a first active metal component loaded on the carrier, a macroporous alumina outer layer coated on the surface of the matrix inner layer, and a second active metal component loaded inside and on the surface of the macroporous alumina outer layer. The catalyst is applied to the residual oil hydrodesulfurization reaction, significantly improving the hydrodesulfurization activity of the catalyst and prolonging the operation time of the device.

[0036] 2. The residual oil hydrodesulfurization catalyst of the present invention adopts two impregnations and two calcinations, which can effectively regulate the relative content of tetrahedral molybdenum and octahedral molybdenum in the final catalyst; wherein the catalyst surface after one impregnation is covered with an outer layer of alumina, which can effectively regulate the pore structure outside the catalyst, effectively avoiding the deposition of coke on the catalyst surface, and combined with the active metal components impregnated in the second step, the hydrogenation capacity of the catalyst surface is improved. During the reaction process, the macromolecules in the residual oil can successively enter the outer layer of the catalyst and the inner layer of the matrix for hydrogenation reaction, the utilization rate of the active metal is high, and the overall anti-coking performance of the catalyst is good. In addition, the desulfurization performance and stability of the catalyst are also relatively good. In summary, the method of the present invention significantly improves the desulfurization performance and stability of the catalyst through the comprehensive coordination of each step. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a Raman spectrum of the catalyst surface obtained in Example 1;

[0038] Figure 2 This is a Raman spectrum of the catalyst surface obtained in Example 2;

[0039] Figure 3 This is a Raman spectrum of the catalyst surface obtained in Comparative Example 1;

[0040] Figure 4 This is the Raman spectrum of the catalyst surface obtained in Comparative Example 2. DETAILED DESCRIPTION

[0041] In the present invention, the Raman spectroscopic characterization of the catalyst was performed using a DXR Microscope type DXR micro Raman spectrometer from Thermo Scientific. 1 The peak nearby is the peak of tetrahedral molybdenum, at 960cm- 1 The nearby peak is the peak of octahedral molybdenum, and the contents of tetrahedral molybdenum and octahedral molybdenum are calculated based on the area under the same baseline.

[0042] In the present invention, the ASAP-2420 physical adsorption instrument of the Michael Company is used to characterize the pore structure (SVD) and specific surface area of ​​the catalyst. The pore volume and pore diameter of the outer layer of the macroporous alumina involved are obtained by mercury intrusion testing.

[0043] The technical solutions and effects of the present invention are further described below in conjunction with embodiments, but are not limited to the following embodiments.

[0044] Example 1

[0045] (1) Prepare 300 g of residual oil hydrodesulfurization alumina support (the pore volume of the support is 0.72 cm 3 / g, specific surface area is 289m 2 / g), dried at 120°C for 6h and set aside. Prepare a first active metal impregnation solution with a volume of 96.6ml, wherein the content of MoO3 is 30.26g / 100ml and the content of NiO is 9.96g / 100ml. The above-mentioned carrier is impregnated with the prepared first active metal impregnation solution (the amount of molybdenum oxide introduced into the catalyst by the first active metal impregnation solution accounts for 38% of the total molybdenum oxide loading in the catalyst, and the amount of nickel oxide introduced into the catalyst by the first active metal impregnation solution accounts for 38% of the total nickel oxide loading in the catalyst), and the amount used is 35% of the saturated water absorption rate of the carrier. After the impregnation, dry at 120°C for 6h, and then carry out the first calcination, and heat to 650°C at a heating rate of 3.0°C / min for 3h to obtain catalyst intermediate A.

[0046] (2) Preparation of binder solution: Dissolve 26 g of starch in 730 g of pure water, heat and stir during mixing until the solid is uniformly dissolved. Preparation of macroporous pseudo-boehmite gel: Weigh 26 g of aluminum sulfate, add 2.6 g of phosphoric acid, adjust the pH value to 3.5, and hydrothermally treat at 260°C for 3 h. Finally, the concentration of alumina in the macroporous pseudo-boehmite gel is 28 g / L. Immerse the catalyst intermediate A in the above-mentioned binder for 3.5 min and then take it out, wipe off the excess binder solution, leave it at room temperature for 40 min, then add it to the above-mentioned macroporous pseudo-boehmite gel and stir it for 12 min, until the gel adheres to the surface and then take it out, centrifuge it in a high-speed centrifuge for 4 min, dry it at 120°C for 6 h, and calcine it at 550°C for 4 h to obtain the residual oil hydrodemetallization catalyst intermediate B.

[0047] (3) Prepare a second active metal impregnation solution with a volume of 285.7 ml, wherein the content of MoO3 is 10.23 g / 100 ml and the content of NiO is 3.37 g / 100 ml. Spray the second active metal impregnation solution onto the catalyst intermediate B in a saturated impregnation manner (the amount of molybdenum oxide introduced into the catalyst by the second active metal impregnation solution accounts for 62% of the total molybdenum oxide loading in the catalyst, and the amount of nickel oxide introduced into the catalyst by the second active metal impregnation solution accounts for 62% of the total nickel oxide loading in the catalyst). After the impregnation, dry at 120°C for 6 hours, and then perform a third calcination, heating to 500°C at a heating rate of 1.0°C / min for 6 hours. Thus, the residue hydrodesulfurization catalyst CAT-1 is obtained.

[0048] The pore volume of the matrix inner layer in catalyst CAT-1 is 0.53 cm 3 / g, the thickness of the macroporous alumina layer is 104 μm, and the pore volume is 0.91 cm 3 / g, the pore volume with a pore diameter of 50-180nm accounts for 34% of the total pore volume, and the ratio of tetrahedral molybdenum to octahedral molybdenum is 0.13.

[0049] Example 2

[0050] Compared with Example 1, the difference is that the first calcination in step (1) adopts a programmed temperature rising method, and the temperature is raised to 600°C at a heating rate of 2.5°C / min for 4 hours; in step (2), the binder solution is prepared by dissolving 26 grams of dextrin in 730 grams of pure water, heating and stirring until the solid is uniformly dissolved; in step (2), the stirring time in the macroporous pseudo-boehmite gel is 10 minutes. Thus, the residue oil hydrodesulfurization catalyst CAT-2 is obtained.

[0051] The pore volume of the matrix inner layer in catalyst CAT-2 is 0.55 cm 3 / g, the thickness of the macroporous alumina layer is 98 μm, and the pore volume is 0.94 cm3 / g, the pore volume with a pore diameter of 50-180nm accounts for 38% of the total pore volume, and the ratio of tetrahedral molybdenum to octahedral molybdenum is 0.20.

[0052] Example 3

[0053] Compared with Example 1, the difference is that the volume of the first active metal impregnation solution in step (1) is 96.6 ml, wherein the content of MoO3 is 26.84 g / 100 ml, and the content of NiO is 9.89 g / 100 ml (the amount of molybdenum oxide introduced into the catalyst by the first active metal impregnation solution accounts for 45% of the total molybdenum oxide loading in the catalyst, and the amount of nickel oxide introduced into the catalyst by the first active metal impregnation solution accounts for 45% of the total nickel oxide loading in the catalyst). The stirring time in the macroporous pseudo-boehmite gel in step (2) is 8 min. At the same time, the volume of the second active metal impregnation solution in step (3) is 271.4 ml, wherein the content of MoO3 is 9.55 g / 100 ml, and the content of NiO is 3.52 g / 100 ml (the amount of molybdenum oxide introduced into the catalyst by the second active metal impregnation solution accounts for 55% of the total molybdenum oxide loading in the catalyst, and the amount of nickel oxide introduced into the catalyst by the second active metal impregnation solution accounts for 55% of the total nickel oxide loading in the catalyst). That is, the residue oil hydrodesulfurization catalyst CAT-3 is obtained.

[0054] The pore volume of the inner layer of the catalyst CAT-3 matrix is ​​0.57 cm 3 / g, the thickness of the macroporous alumina layer is 95 μm, and the pore volume is 0.88 cm 3 / g, the pore volume with a pore diameter of 50-180nm accounts for 32% of the total pore volume, and the ratio of tetrahedral molybdenum to octahedral molybdenum is 0.32.

[0055] Example 4

[0056] Compared with Example 1, the difference is that when preparing the macroporous pseudo-boehmite gel in step (2), 1.6 g of phosphoric acid is added, and the macroporous pseudo-boehmite gel is hydrothermally treated at 180° C. for 4 h, the concentration of alumina in the macroporous pseudo-boehmite is 22 g / L, and the stirring time in the macroporous pseudo-boehmite gel is 6 min; in the third calcination in step (3), a programmed temperature is used, and the temperature is raised to 450° C. at a heating rate of 1.5° C. / min and calcined for 4 h. The residue oil hydrodesulfurization catalyst CAT-4 is obtained.

[0057] The pore volume of the matrix inner layer in catalyst CAT-4 is 0.54 cm 3 / g, the thickness of the outer layer of alumina is 92μm, and the pore volume is 0.93cm 3 / g, the pore volume with a pore diameter of 50-180nm accounts for 35% of the total pore volume, and the ratio of tetrahedral molybdenum to octahedral molybdenum is 0.43.

[0058] Example 5

[0059] Compared with Example 1, the difference is that the catalyst intermediate A dried in step (2) is immersed in the binder for 1.0 min, then taken out, the excess binder solution is wiped off, and the mixture is left at room temperature for 20 min. The treated catalyst intermediate A is added to the macroporous pseudo-boehmite gel and stirred for 4 min, centrifuged in a high-speed centrifuge for 6 min, dried at 140° C. for 4 h, and calcined at 500° C. for 3 h. The residue hydrodesulfurization catalyst CAT-5 is obtained.

[0060] The pore volume of the matrix inner layer in catalyst CAT-5 is 0.52 cm 3 / g, the thickness of the macroporous alumina layer is 88 μm, and the pore volume is 0.97 cm 3 / g, the pore volume with a pore diameter of 50-180nm accounts for 42% of the total pore volume, and the ratio of tetrahedral molybdenum to octahedral molybdenum is 0.48.

[0061] Comparative Example 1

[0062] Compared with Example 1, the difference is that step (3) is removed and there is only one impregnation process, that is, in step (1), the first active metal impregnation solution is prepared with a volume of 276.0 ml, wherein the content of MoO3 is 17.08 g / 100 ml and the content of NiO is 3.62 g / 100 ml. A residue oil hydrodesulfurization catalyst DCAT-1 is obtained.

[0063] The pore volume of the matrix inner layer in catalyst DCAT-1 is 0.57 cm 3 / g, the thickness of the macroporous alumina layer is 86 μm, and the pore volume is 1.02 cm 3 / g, the pore volume with a pore diameter of 50-180nm accounts for 46% of the total pore volume, and the ratio of tetrahedral molybdenum to octahedral molybdenum is 2.28.

[0064] Comparative Example 2

[0065] Compared with Example 1, the difference is that steps (2) and (3) are removed, and the first active metal impregnation solution is directly prepared with a volume of 96.6 ml, wherein the content of MoO3 is 48.80 g / 100 ml, and the content of NiO is 10.35 g / 100 ml, and the alumina carrier is impregnated with the solution and then the first calcination is performed (the process is the same as that of Example 1). The residue oil hydrodesulfurization catalyst DCAT-2 is obtained.

[0066] The pore volume of the matrix inner layer in catalyst DCAT-2 is 0.51 cm 3 / g, the ratio of tetrahedral molybdenum to octahedral molybdenum is 2.66.

[0067] Comparative Example 3

[0068] Compared with Example 1, the difference is that in the process of preparing the macroporous pseudo-boehmite gel in step (2), phosphoric acid is not added, and the treatment temperature is hydrothermally treated at 200° C. for 6 hours. In addition, the temperature is raised to 550° C. for 3 hours at a heating rate of 2.0° C. / min during the first and third calcinations. The residue oil hydrodesulfurization catalyst DCAT-3 is obtained.

[0069] The pore volume of the matrix inner layer in catalyst DCAT-3 is 0.52 cm 3 / g, the thickness of the macroporous alumina layer is 86 μm, and the pore volume is 0.92 cm 3 / g, the pore volume with a pore diameter of 50-180nm accounts for 41% of the total pore volume, and the ratio of tetrahedral molybdenum to octahedral molybdenum is 2.75.

[0070] Evaluation test

[0071] The activity stability of the example catalysts CAT-1 to CAT-5 and the comparative catalysts DCAT-1 to DCAT-3 were evaluated on a 200 ml fixed bed hydrogenation test device. The raw oil used was a certain atmospheric residue (sulfur content was 4.67%). The experimental process conditions are shown in Table 1. Based on the desulfurization rate of the catalyst DCAT-1 when it was operated for 100 hours, the relative desulfurization rates of other catalysts can be obtained. The evaluation results of the catalysts are shown in Table 2.

[0072] Table 1 Experimental process conditions

[0073] Reaction temperature, °C 385 Reaction pressure, MPa 15.0 <![CDATA[Space velocity, h- 1 > 0.5 Hydrogen to oil ratio, V / V 750

[0074] Table 2 Evaluation results of catalysts of various examples

[0075]

[0076] It can be seen from Table 1 and Table 2 that the hydrodesulfurization catalyst prepared by the present invention has better hydrodesulfurization activity than the comparative example, and has better stability during the long-term operation of the catalyst.

Claims

1. A method for preparing a residue hydrodesulfurization catalyst, characterized in that: The catalyst comprises a matrix inner layer composed of a carrier and a first active metal component loaded on the carrier, and a catalyst outer layer composed of a macroporous alumina layer and a second active metal component, wherein the first active metal component and the second active metal component both comprise metal molybdenum and nickel; the thickness of the macroporous alumina layer is 85-105 μm; wherein, in the catalyst, the content ratio of tetrahedral molybdenum to octahedral molybdenum, calculated as Mo atoms, is 0.10-0.50; the pore volume of the macroporous alumina layer is 0.85-1.00 cm 3 / g, the pore volume of pores with a pore size of 50-180 nm accounts for 20%-60% of the total pore volume; (1) spraying a first active metal impregnation solution onto a carrier in an unsaturated impregnation manner, followed by drying and a first calcination to obtain a catalyst intermediate A; (2) adding the catalyst intermediate A obtained in step (1) into macroporous pseudo-boehmite gel, stirring and soaking, taking out after the surface is coated with gel, drying and second calcining to obtain intermediate B; (3) spraying the second active metal impregnation solution onto the intermediate B obtained in step (2) in a saturated impregnation manner, drying and third calcining to obtain the residual oil hydrodesulfurization catalyst; The temperature of the first roasting is 550-650°C, and the temperature of the third roasting is 450-500°C, and the temperature of the third roasting is 50-200°C lower than that of the first roasting; The macroporous pseudo-boehmite gel contains one or more of fluorine, phosphorus, silicon or boron as an auxiliary agent; the auxiliary agent is added in an amount of 2.0% to 20% of the mass of the alumina in terms of element, based on the mass of the alumina; In step (1), the amount of the first active metal impregnation solution used is 20% to 50% of the saturated water absorption rate of the carrier.

2. The preparation method according to claim 1, characterized in that: The carrier is an alumina-based carrier, and the pore volume of the carrier is 0.60-0.90 cm 3 / g, with a specific surface area of ​​170~340m 2 / g.

3. The preparation method according to claim 1, characterized in that: In the catalyst, based on the mass of the catalyst, the content of molybdenum oxide is 5.0% to 25.0%, and the content of nickel oxide is 2.0% to 10.0%.

4. The preparation method according to claim 1, characterized in that: The first calcination condition is: the calcination time is 2 to 6 hours, and the calcination atmosphere is one or more of air, water vapor, and nitrogen.

5. The preparation method according to claim 1, characterized in that: The calcination atmosphere of the first calcination is air.

6. The preparation method according to claim 1, characterized in that: Before the catalyst intermediate A described in step (2) is added to the macroporous pseudo-boehmite gel, the catalyst intermediate A is soaked in a binder solution, wherein the binder content in the binder solution is 3% to 45%.

7. The preparation method according to claim 6, characterized in that: The mass content of the adhesive in the adhesive solution is 3%~30%.

8. The preparation method according to claim 6, characterized in that: The adhesive is one or more of starch, dextrin, polyvinyl alcohol or carboxymethyl cellulose.

9. The preparation method according to claim 6, characterized in that: The catalyst intermediate A is immersed in the binder solution for 0.3 min to 5 min, excess binder solution is drained off, and the catalyst intermediate A is left at room temperature for 10 to 80 min.

10. The preparation method according to claim 1, characterized in that: The macroporous pseudo-boehmite gel described in step (2) is obtained by the following method: using an inorganic aluminum source as a raw material, without adding a template agent, adding an auxiliary agent, adjusting the pH value to 3.0-3.4, and hydrothermally treating at 180-320° C. for 3.5-6.0 hours.

11. The preparation method according to claim 1, characterized in that: The concentration of alumina in the macroporous pseudo-boehmite gel is 15g / L~60g / L.

12. The preparation method according to claim 1, characterized in that: The concentration of alumina in the macroporous pseudo-boehmite gel is 18g / L~55g / L.

13. The preparation method according to claim 1, characterized in that: In step (2), the catalyst intermediate A is added to the macroporous pseudo-boehmite gel and stirred for 0.5 to 20 minutes. After the surface is coated with gel, it is taken out and centrifuged to remove excess gel on the surface for 1 to 10 minutes. Then, it is dried at 120 to 180° C. for 2 to 12 hours.

14. The preparation method according to claim 1, characterized in that: The second calcination condition described in step (2) is: calcination at a temperature of 450-650° C. for 2-8 hours.

15. The preparation method according to claim 1, characterized in that: The third calcination conditions in step (3) are: a heating rate of 1°C / min to 3°C / min, a calcination time of 3 to 6 hours, and a calcination atmosphere of one or more of air, water vapor, and nitrogen.

16. The preparation method according to claim 1, characterized in that: The calcination atmosphere for the third calcination in step (3) is air.

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