Residue hydro-decarbon residue catalyst, its preparation method and application

Abstract

This invention discloses a catalyst for hydrotreating and decarbonizing residual oil, its preparation method, and its application. The catalyst comprises a modified alumina support and a hydrotreating active metal component; the modified alumina support includes alumina and a modifying agent, wherein the modifying agent is magnesium, and the six-coordinated Al on the support accounts for 75%-95% of the total aluminum. The catalyst of this invention exhibits excellent hydrotreating and decarbonizing performance, and is particularly suitable for processing fluidized bed hydrotreating tail oil with poor oil properties.

Description

Technical Field

[0001] This invention belongs to the field of oil refining technology, specifically relating to a catalyst for hydrotreating and decarbonizing residual oil, its preparation method, and its application. Background Technology

[0002] Catalysts for residue hydrotreating typically use γ-alumina as a support. However, the support surface has low smoothness, excessive randomness in microscopic surface properties, and a wide acidity distribution, making it very difficult to finely control the active phase of the catalyst. Regions with highly uneven metal distribution, rough surfaces, and many cavities tend to be more acidic and have higher active metal dispersion, resulting in higher catalytic activity but lower stability. Conversely, regions with relatively smooth surfaces, fewer cavities, lower acidity, and lower active metal dispersion exhibit higher catalyst stability but lower activity.

[0003] To improve the performance of residual oil catalysts, researchers have proposed a variety of modification methods for alumina supports.

[0004] CN201310499295.7 discloses a method for preparing an alumina support for a residue oil hydrodemetallization catalyst. The method includes: first, mixing a physical pore-expanding agent, boehmite dry powder, an extrusion aid, and a solvent to form a plastic body, extruding it into strips, and drying it; then, impregnating the dried support with a chemical pore-expanding agent using an unsaturated spray; finally, drying and calcining the chemically impregnated support to obtain the alumina support for the residue oil hydrodemetallization catalyst. The alumina prepared by this method has an excellent pore structure, but its surface uniformity is not sufficiently improved, thus affecting the dispersion effect of the active metal component.

[0005] CN201110322448.1 discloses a method for preparing an alumina support for a residue oil hydrotreating catalyst. This method uses activated carbon fibers with well-developed pore structures, impregnated with and adsorbed inorganic aluminum salts as a pore-expanding agent, mixed with an alumina precursor, kneaded and shaped, and then dried and calcined to obtain the alumina support. The alumina support obtained by this method has a high specific surface area, which is beneficial for removing large components from heavy residue oil, thus helping to maintain the activity of the hydrotreating catalyst and extend its operating cycle. However, as an alumina support, its surface uniformity is poor, which can easily cause the active metal to aggregate in certain areas during the loading process, affecting the efficient utilization of the active metal.

[0006] CN200410050726.2 discloses a method for preparing an alumina support. The method includes neutralizing an acidic aluminum salt with a basic aluminate, aging the neutralized material, followed by filtration, washing, shaping, drying, and calcination to obtain the alumina support. The aging is carried out at a temperature and pH higher than the neutralization temperature. However, the alumina support prepared by this method exhibits poor surface uniformity, affecting the subsequent loading of active metals and the overall activity of the catalyst. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a catalyst for hydrotreating and removing residual carbon from residue oil, its preparation method, and its application. The catalyst of this invention exhibits excellent hydrotreating carbon removal performance and is particularly suitable for processing fluidized bed tail oils with poor oil properties.

[0008] In γ-alumina, Al exists primarily in two forms: stable six-coordinate framework aluminum, which shows a shift of -10 to 30 ppm in Al NMR, and less stable four-coordinate non-framework aluminum, which shows a shift of 40 to 80 ppm in Al NMR. The inventors discovered that when the alumina surface is predominantly composed of six-coordinate aluminum, the surface becomes smooth and homogeneous, while simultaneously improving the activity and stability of the catalyst. The inventors creatively introduced magnesium into the alumina surface while simultaneously removing non-framework aluminum, achieving a smooth surface and homogeneous properties, thus realizing this invention.

[0009] The first aspect of the present invention provides a catalyst for hydrotreating and decarbonizing residual oil, comprising a modified alumina support and a hydrotreating active metal component; the modified alumina support comprises alumina and a modifying agent, wherein the modifying agent is magnesium, and the six-coordinated Al on the support accounts for 75%-95% of the total aluminum, preferably 80%-90%.

[0010] Furthermore, based on the mass of the carrier, the magnesium content, calculated as MgO, is 1%-12%, preferably 2%-10%.

[0011] Furthermore, based on the mass of the carrier, the mass content of alumina is 83%-99%, preferably 85%-98%.

[0012] Furthermore, the carrier may also contain one or more conventional additives such as silicon, phosphorus, and boron. Based on the mass of the carrier, the mass content of the conventional additives, calculated as elements, is less than 5%.

[0013] Furthermore, the carrier has the following properties: a specific surface area of ​​180-420 m². 2 / g, preferably 220-360m 2 / g, pore volume 0.5-1.1m 2 / g, preferably 0.6-1.0m 2 / g.

[0014] Furthermore, the hydrogenation active metal component is selected from at least one group VIB and group VIII metals. Preferably, the group VIB metal is selected from at least one group of tungsten and molybdenum, and the group VIII metal is selected from at least one group of nickel and cobalt.

[0015] Furthermore, based on the mass of the catalyst, the content of Group VIB metals as +6 oxides is 10%-32%, preferably 15%-26%, and the content of Group VIII metals as +2 oxides is 2%-8%, preferably 3%-7%.

[0016] Furthermore, based on the mass of the catalyst, the content of the modified alumina support is 55%-88%, preferably 64%-82%.

[0017] The second aspect of the present invention provides a method for preparing the above-mentioned catalyst, including the preparation of a modified alumina support and the loading of a hydrogenation active metal component, wherein the method for preparing the modified alumina support includes: mixing the alumina support with an organic solution of magnesium chloride, performing a closed heating treatment, and performing an activation treatment to obtain the modified alumina support.

[0018] Furthermore, the alumina support is a γ-alumina support. The alumina support can be a conventional alumina support used in residue hydrotreating catalysts, preferably an alumina support used in residue hydrotreating decarbonization catalysts. In addition to alumina, the alumina support may also contain additives, such as one or more of silicon, phosphorus, and boron. The additives in the alumina support account for less than 5% by mass, based on elemental composition.

[0019] Furthermore, in the preparation method of the modified alumina carrier, the organic solution of magnesium chloride contains one or more of the organic solvents glycerol, 1,4-butanediol, and 1,2-butanediol.

[0020] Furthermore, in the preparation method of the modified alumina carrier, the mass content of magnesium chloride in the organic solution of magnesium chloride is 2%-10%, preferably 3%-8%.

[0021] Furthermore, in the preparation method of the modified alumina support, the mass ratio of the alumina support to the organic solution of magnesium chloride is 1:5-1:50, preferably 1:10-1:30.

[0022] Furthermore, in the preparation method of the modified alumina carrier, the conditions for the closed heating treatment are as follows: inert atmosphere, pressure of 0.05-0.5MPa, preferably 0.1-0.4MPa, treatment temperature of 160-230℃, preferably 180-210℃, and treatment time of 4-24 hours, preferably 6-16 hours.

[0023] Further, in the preparation method of the modified alumina carrier, after closed heating treatment, the solid is separated and washed with deionized water, preferably 2-10 times, at a washing temperature of 30-80℃, preferably 40-70℃, and the amount of deionized water used each time is 5-50 times, preferably 10-40 times, of the solid to be washed. The washed carrier is then activated under the following conditions: a treatment temperature of 120-350℃, preferably 160-320℃, a treatment time of 2-10 hours, preferably 2-8 hours, and an oxygen-containing atmosphere, to obtain the modified alumina carrier.

[0024] Furthermore, the method for loading the active metal component onto the modified alumina support preferably employs an impregnation method, and more preferably an equal-volume impregnation method. When using the impregnation method, the catalyst is obtained after drying and calcination. The drying and calcination can be performed using conventional methods and conditions. Preferably, the drying temperature is 80-200℃, more preferably 100-180℃, and the drying time is 2.0-10.0 hours, more preferably 4.0-8.0 hours; the calcination temperature is 300-600℃, more preferably 350-500℃, and the calcination time is 2.0-8.0 hours, more preferably 3.0-5.0 hours.

[0025] A third aspect of the present invention provides the application of the above-described catalyst in the hydrotreating of residual oil. Further, in this application, the catalyst is used as a hydrodecarbonization catalyst.

[0026] Furthermore, the residual oil feedstock can be a conventional residual oil feedstock, such as at least one of atmospheric residue, vacuum residue, or deasphalted oil.

[0027] Furthermore, the residue feedstock can also be used to process fluidized bed hydrotreating tail oil with poor oil properties. Furthermore, the properties of the fluidized bed hydrotreating tail oil include: a density of 0.90-1.05 g / cm³. 3 The sulfur content is 1000-15000 ppm, preferably 1500-12000 ppm, the nitrogen content is 500-5000 ppm, and the carbon residue content is 5%-25%.

[0028] Furthermore, the hydrogenation treatment conditions are as follows: reaction temperature 300-450℃, preferably 350-420℃; reaction pressure 12-25MPa, preferably 15-22MPa; and liquid hourly space velocity 0.05-0.6h. -1 Preferably 0.1-0.4h -1 .

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] 1. The catalyst of this invention uses a modified alumina support and is characterized by nuclear magnetic resonance. It is mainly composed of six-coordinated aluminum, that is, six-coordinated Al accounts for 75%-95% (preferably 80%-90%) of the total aluminum. When used in the hydrotreating process of residual oil, it can improve the hydrotreating and decarbonization activity and stability of the catalyst.

[0031] 2. In the preparation process of the modified alumina support used in the catalyst of this invention, the non-framework aluminum in the alumina support is dissolved in a chlorine-containing organic solution to generate AlCl3. Since aluminum chloride is a covalent compound with very low melting and boiling points and capable of sublimation, it can volatilize from a high-boiling-point liquid at a relatively low temperature, thereby promoting the continuous dissolution of tetracoordinated aluminum in the alumina into the solution, completing the dealuminization process. Simultaneously, magnesium in the solution enters the alumina surface to balance the charge, playing a role in modifying the alumina surface throughout the process. The resulting modified alumina support has a surface mainly composed of hexacoordinated aluminum with good surface uniformity. During the impregnation and loading of active metals, the metals can be uniformly dispersed on the support surface, resulting in higher metal utilization. The prepared residue oil hydrodecarbonization catalyst exhibits better hydrodecarbonization activity and stability. Attached Figure Description

[0032] Figure 1 The alumina carrier obtained in Example 1 27 Al MAS NMR spectrum;

[0033] Figure 2 The alumina support obtained in Comparative Example 1 27 Al MAS NMR spectrum;

[0034] Figure 3 The image shows a transmission electron microscope (TEM) image of the catalyst obtained in Example 1.

[0035] Figure 4 This is a transmission electron microscope (TEM) image of the catalyst obtained in Comparative Example 1. Detailed Implementation

[0036] The present invention will be further described below with reference to embodiments, but it should be understood that the scope of protection of the present invention is not limited to the embodiments. In the present invention, unless otherwise expressly stated, percentages and contents are all expressed by mass.

[0037] In this invention, the specific surface area and pore volume of the sample were obtained by liquid nitrogen physical adsorption method on a Micromeritics ASAP 2020M.

[0038] In this invention, nuclear magnetic resonance spectroscopy (NMR) is used to obtain... 27Al MAS NMR spectra were obtained to determine the ratio of six-coordinate framework aluminum and four-coordinate non-framework aluminum in the support, expressed as Al atoms. Nuclear magnetic resonance spectroscopy (NMR) was performed using a Bruker Avance III 500 NMR spectrometer with Topspin 2.0 software. [The text abruptly ends here, likely due to an incomplete sentence or missing information.] 27 For Al MAS NMR spectra, aluminum trichloride was used as the standard, the resonance frequency was 133 MHz, and the experimental conditions were: 4-6 microsecond pulse width and 60-120 second relaxation delay. The obtained... 27 In the Al MAS NMR spectrum, the chemical shifts corresponding to six-coordinate framework aluminum are -10 to 30 ppm, while those corresponding to four-coordinate non-framework aluminum are 40 to 80 ppm. Total aluminum refers to the sum of six-coordinate and four-coordinate aluminum.

[0039] In this invention, the morphology of the active metal lamellar crystals of the sulfide catalyst can be statistically analyzed using TEM characterization. The TEM used is a JEOL JEM 2100 TEM with an accelerating voltage of 120 kV. The sulfidated catalyst is stored in ethanol. During testing, the sample is placed in a mortar, a small amount of alcohol is added, and the mixture is ground for 10 minutes. After standing for a short time, the supernatant is collected and placed in a sample bottle. The sample is diluted with alcohol and then subjected to ultrasonic treatment for 20 minutes. Two to three drops are then added to an ultrathin carbon film using a dropper. The ethanol is evaporated using a heat lamp, and after drying, the film is subjected to microscopic testing. To analyze the lamellar dispersion state of the active metal on the catalyst, the field of view is adjusted to 10 nm. At least 30 high-quality images from different locations are required for each sample.

[0040] In this invention, the unmodified alumina support S-0 used in the following examples and comparative examples was prepared by the following method:

[0041] Weigh 1000.0g of alumina dry adhesive powder, add 20.0g of acetic acid, 20.0g of citric acid, 30.0g of guar gum powder, and 20.0g of cellulose, mix well, then add 1100.0g of an aqueous solution containing 1.5% nitric acid. After rolling for 15.0min, extrude the mixture into strips using a clover-shaped perforated plate with a diameter of 1.8mm. Dry at 140℃ for 4.0h, then calcine at 600℃ for 4.0h. The calcined carrier is designated S-0. The carrier properties are as follows: specific surface area is 312m². 2 / g, pore volume is 0.88cm 3 / g.

[0042] Example 1

[0043] Dissolve 250.0g of magnesium chloride in 3000g of glycerol, and the resulting solution is denoted as G-1.

[0044] 200.0g of S-0 and G-1 were added together into the reactor, sealed with nitrogen, and the reactor pressure was controlled at 0.2MPa. The reactor was heated to 200℃ and stirred thoroughly. After reacting for 10.0 hours, the solid obtained was separated and recorded as Z-1.

[0045] Z-1 was rinsed with 6000 ml of deionized water at 60°C each time, and rinsed 6 times. After rinsing, it was activated at 240°C for 4.0 hours in air atmosphere. The resulting carrier was denoted as S-1.

[0046] Take 30.0g of ammonium heptamolybdate tetrahydrate and 20.0g of nickel nitrate hexahydrate, dissolve them in deionized water, and prepare a 120ml solution, denoted as Q-1.

[0047] Take 100.0g of S-1 support, impregnate it with Q-1, let it stand for 12 hours, dry it at 120℃ for 4.0 hours, and then calcine it at 420℃ for 6.0 hours to obtain the catalyst, which is denoted as Cat-1.

[0048] Example 2

[0049] Dissolve 200.0g of magnesium chloride in 3000g of 1,4-butanediol, and the resulting solution is denoted as G-2.

[0050] 200.0g of S-0 and G-2 were added together into the reactor, sealed with nitrogen, and the reactor pressure was controlled at 0.3MPa. The reactor was heated to 190℃ and stirred thoroughly. After reacting for 6.0 hours, the solid obtained was separated and recorded as Z-2.

[0051] Z-2 was rinsed with 6000 ml of deionized water at 50°C for 6 times. After rinsing, it was activated at 240°C for 4.0 hours in air. The resulting carrier was denoted as S-2.

[0052] Take 25.0g of ammonium heptamolybdate tetrahydrate and 18.0g of nickel nitrate hexahydrate, dissolve them in deionized water, and prepare a 120ml solution, which is denoted as Q-2.

[0053] Take 100.0g of S-2 support, impregnate it with Q-2, let it stand for 12 hours, dry it at 120℃ for 4.0 hours, and then calcine it at 420℃ for 6.0 hours to obtain the catalyst, which is denoted as Cat-2.

[0054] Example 3

[0055] Dissolve 150.0g of magnesium chloride in 3000g of 1,2-butanediol, and the resulting solution is denoted as G-3.

[0056] 200.0g of S-0 and G-3 were added together into the reactor, sealed with nitrogen, and the reactor pressure was controlled at 0.3MPa. The reactor was heated to 200℃ and stirred thoroughly. After reacting for 6.0 hours, the solid obtained was denoted as Z-3.

[0057] Z-3 was rinsed with 6000 ml of deionized water at 50°C each time, and rinsed 6 times. After rinsing, it was activated at 300°C for 3.0 hours in air atmosphere. The resulting carrier was denoted as S-3.

[0058] Take 22.0g of ammonium heptamolybdate tetrahydrate and 15.0g of nickel nitrate hexahydrate, dissolve them in deionized water, and prepare a 120ml solution, which is denoted as Q-3.

[0059] Take 100.0g of S-3 support, impregnate it with Q-3, let it stand for 12 hours, dry it at 120℃ for 4.0 hours, and then calcine it at 420℃ for 6.0 hours to obtain the catalyst, which is denoted as Cat-3.

[0060] Comparative Example 1

[0061] Take 100.0g of S-0 support, impregnate it with 120ml of Q-2, let it stand for 12 hours, dry it at 120℃ for 4.0 hours, and then calcine it at 420℃ for 6.0 hours to obtain the catalyst, which is denoted as DCT-1.

[0062] Comparative Example 2

[0063] Take 12.0g of magnesium nitrate, dissolve it in deionized water, and prepare a 110ml solution, which is denoted as DG-2.

[0064] Take 100.0g of carrier S-0, impregnate S-0 with DG-2, let stand for 12 hours, dry at 120℃ for 4.0 hours, and then calcine at 400℃ for 6.0 hours to obtain carrier DS-2.

[0065] DS-2 was impregnated with 110 ml of Q-2, allowed to stand for 12 hours, dried at 120°C for 4.0 hours, and then calcined at 420°C for 6.0 hours to obtain the catalyst, denoted as DCT-2.

[0066] Comparative Example 3

[0067] Dissolve 150.0g of magnesium chloride in 3000g of deionized water to obtain a solution labeled DG-3.

[0068] 200.0g of S-0 and DG-3 were added together into a reactor, sealed with nitrogen, and the reactor pressure was controlled at 0.3MPa. The reactor was heated to 90℃ and stirred thoroughly. After reacting for 6.0 hours, the resulting solid was denoted as DZ-3.

[0069] DZ-3 was rinsed with 6000 ml of deionized water at 50°C for 6 times. After rinsing, it was dried at 240°C for 4.0 hours. The resulting carrier was denoted as DS-3.

[0070] Take 100.0g of DS-3 support, impregnate it with 110ml of Q-2, let it stand for 12 hours, dry it at 120℃ for 4.0 hours, and then calcine it at 420℃ for 6.0 hours to obtain the catalyst, denoted as DCT-3.

[0071] Catalyst sulfidation

[0072] 20.0 g of catalysts Cat-1, Cat-2, Cat-3, DCT-1, DCT-2, and DCT-3 were respectively subjected to sulfidation at a temperature of 320℃ for 12.0 hours. The hydrogen pressure during sulfidation was 5.0 MPa, and the hydrogen space velocity was 20 ml / min·g. 催化剂 The liquid hourly space velocity of the vulcanizing liquid is 1.0 h⁻¹. -1 The sulfiding agent was a cyclohexane solution of 5.0% DMDS by mass. The sulfided catalysts were designated as SCT-1, SCT-2, SCT-3, DSCT-1, DSCT-2, and DSCT-3, respectively.

[0073] Table 1 shows the elemental analysis of the catalysts obtained in each example.

[0074] Catalyst number <![CDATA[MoO3 / wt%]]> NiO / wt% MgO / wt% <![CDATA[Al2O3 / wt%]]> Cat-1 18.6 3.9 3.7 73.8 Cat-2 16.1 3.7 3.3 76.9 Cat-3 14.5 3.2 2.7 79.6 DCT-1 16.0 3.5 0 80.5 DCT-2 16.2 3.6 2.6 77.6 DCT-3 16.1 3.6 3.1 77.2

[0075] Table 2 shows the NMR analysis of aluminum in the carriers obtained for each example.

[0076]

[0077] Table 3 shows the properties of the carriers obtained in each example.

[0078] Carrier number Specific surface area, m2 / g Pore ​​volume, mL / g S-1 266 0.79 S-2 271 0.80 S-3 270 0.79 S-0 312 0.88 DS-2 273 0.77 DS-3 275 0.78

[0079] Table 4 shows the TEM characterization analysis of the catalysts obtained in each example.

[0080]

[0081] Examples 4-6

[0082] Using fluidized bed residue hydrotreating oil as feedstock, and employing a fixed-bed hydrotreating process, hydrotreating evaluation experiments were conducted on catalysts SCT-1, SCT-2, and SCT-3 obtained in Examples 1-3, after sulfidation. The properties of the fluidized bed residue hydrotreating oil are shown in Table 5.

[0083] Table 5 Properties of oils produced by hydrotreating fluidized bed residue oil

[0084] project numerical values project numerical values <![CDATA[Density / g·cm -3 > 0.980 Nitrogen content, μg / g 3292 Vanadium + Nickel content, μg / g 39.6 H / C atomic ratio 1.51 Sulfur content, μg / g 23051 Kang's carbon residue, % 17.9

[0085] A hydroprotective agent (FZC-100B) and a hydrodemetallization catalyst (FZC-204A) were loaded before the aforementioned catalyst. The volume ratio of the protective agent, the hydrodemetallization catalyst, and the catalyst obtained in the examples was 1:2:4. The operating conditions were: reaction temperature 380°C, reaction pressure 20.0 MPa, hydrogen-to-oil volume ratio 1800:1, and liquid hourly space velocity (LHSV) 0.25 h⁻¹. -1 After 1500 hours of reaction evaluation, the residual carbon value, sulfur content, and nitrogen content of the hydrogenated oil fraction at a temperature not lower than 300℃ were analyzed, and the results are shown in Table 6.

[0086] Comparative Examples 4-6

[0087] The hydrogenated residue oil from the fluidized bed reactor (see Table 4) was used as feedstock, and a fixed-bed process was employed. The activity of catalysts DSCT-1, DSCT-2, and DSCT-3 obtained in Comparative Examples 1-3 was evaluated. A hydrotreating protectant (FZC-100B) and a hydrodemetallization catalyst (FZC-204A) were loaded before the above catalysts. The volume ratio of the protectant, hydrodemetallization catalyst, and the catalysts obtained in the comparative examples was 1:2:4. The operating conditions were: reaction temperature 380℃, reaction pressure 20.0 MPa, hydrogen-to-oil volume ratio 1800:1, and liquid hourly space velocity (LISH) 0.25 h⁻¹. -1 After 1500 hours of reaction evaluation, the residual carbon value, sulfur content, and nitrogen content of the hydrogenated oil fraction at a temperature not lower than 300℃ were analyzed, and the results are shown in Table 6.

[0088] Table 6 Properties of Oils Generated by Fixed-Bed Hydrogenation

[0089]

[0090]

[0091] As can be seen from the evaluation results in Table 6, the catalyst of the present invention has good hydrodecarbonization activity, as well as good hydrodenitrogenation and hydrodesulfurization activity when hydrotreating low-sulfur fluidized bed residue oil to produce oil.

Claims

1. A catalyst for hydrotreating and removing residual carbon from residual oil, comprising a modified alumina support and a hydrotreating active metal component; wherein the modified alumina support comprises alumina and a modifying agent, wherein the modifying agent is magnesium, and the six-coordinated Al on the support accounts for 80%-95% of the total aluminum; Based on the mass of the carrier, the magnesium content (calculated as MgO) is 1%-12%; based on the mass of the carrier, the alumina content is 83%-99%. The hydrogenation active metal component is selected from at least one group VIB and group VIII metals; based on the mass of the catalyst, the content of group VIB metals as +6 oxides is 10%-32%, and the content of group VIII metals as +2 oxides is 2%-8%. The catalyst preparation method includes: preparation of modified alumina support and loading of hydrogenation active metal component, wherein the preparation method of modified alumina support includes: mixing alumina support with an organic solution of magnesium chloride, performing closed heating treatment, and activating treatment to obtain modified alumina support; In the organic solution of magnesium chloride, the organic solvent is one or more of glycerol, 1,4-butanediol, and 1,2-butanediol; and the mass content of magnesium chloride in the organic solution of magnesium chloride is 2%-10%.

2. The catalyst according to claim 1, characterized in that, The six-coordinated Al on the carrier accounts for 80%-90% of the total aluminum.

3. The catalyst according to claim 1, characterized in that, Based on the mass of the carrier, the magnesium content (calculated as MgO) is 2%-10%; and / or, based on the mass of the carrier, the alumina content is 85%-98%.

4. The catalyst according to claim 1, characterized in that, The carrier has the following properties: specific surface area of ​​180-420 m². 2 / g, with a pore volume of 0.5-1.1mL / g.

5. The catalyst according to claim 4, characterized in that, The carrier has the following properties: specific surface area of ​​220-360 m². 2 / g, with a pore volume of 0.6-1.0mL / g.

6. The catalyst according to claim 1, characterized in that, The carrier also contains one or more of the additives silicon, phosphorus, and boron. Based on the mass of the carrier, the mass content of the additives, calculated by element, is less than 5%.

7. The catalyst according to claim 1, characterized in that, Group VIB metals are selected from at least one of tungsten and molybdenum, and Group VIII metals are selected from at least one of nickel and cobalt.

8. The catalyst according to claim 1, characterized in that, Based on the mass of the catalyst, the content of Group VIB metals as +6 oxides is 15%-26%, and the content of Group VIII metals as +2 oxides is 3%-7%.

9. A method for preparing the catalyst according to any one of claims 1-8, comprising: Preparation of modified alumina support and loading of hydrogenated active metal components, wherein the preparation method of the modified alumina support includes: mixing the alumina support with an organic solution of magnesium chloride, performing a closed heating treatment, and an activation treatment to obtain the modified alumina support; In the organic solution of magnesium chloride, the organic solvent is one or more of glycerol, 1,4-butanediol, and 1,2-butanediol; and the mass content of magnesium chloride in the organic solution of magnesium chloride is 2%-10%.

10. The preparation method according to claim 9, characterized in that, The alumina support is an alumina-based support used in catalysts for the hydrotreating of residual oil.

11. The preparation method according to claim 10, characterized in that, The alumina support is an alumina-based support used in catalysts for hydrotreating and decarbonizing residual oil.

12. The preparation method according to claim 9, characterized in that, The magnesium chloride organic solution contains 3%-8% by mass of magnesium chloride.

13. The preparation method according to claim 9, characterized in that, The mass ratio of the alumina carrier to the organic solution of magnesium chloride is 1:5 to 1:

50.

14. The preparation method according to claim 13, characterized in that, The mass ratio of the alumina carrier to the organic solution of magnesium chloride is 1:10 to 1:

30.

15. The preparation method according to claim 9, characterized in that, In the preparation method of the modified alumina carrier, the conditions for the closed heating treatment are as follows: inert atmosphere, pressure of 0.05-0.5 MPa, treatment temperature of 160-230℃, and treatment time of 4-24 hours.

16. The preparation method according to claim 15, characterized in that, In the preparation method of the modified alumina carrier, the conditions for the closed heating treatment are as follows: inert atmosphere, pressure of 0.1-0.4 MPa, treatment temperature of 180-210℃, and treatment time of 6-16 hours.

17. The preparation method according to claim 9, characterized in that, In the preparation method of the modified alumina carrier, the activation treatment conditions are as follows: the treatment temperature is 120-350℃, the treatment time is 2-10 hours, and the treatment atmosphere is an oxygen-containing atmosphere.

18. The preparation method according to claim 17, characterized in that, In the preparation method of the modified alumina carrier, the activation treatment conditions are as follows: the treatment temperature is 160-320℃, and the treatment time is 2-8 hours.

19. The preparation method according to claim 9, characterized in that, The method for loading hydrogenated active metal components onto modified alumina carriers employs an impregnation method.

20. The preparation method according to claim 19, characterized in that, The drying and calcination conditions after impregnation are as follows: drying temperature is 80-200℃, drying time is 2.0-10.0 hours; calcination temperature is 300-600℃, calcination time is 2.0-8.0 hours.

21. The preparation method according to claim 20, characterized in that, The drying and calcination conditions after impregnation are as follows: drying temperature is 100-180℃, drying time is 4.0-8.0 hours; calcination temperature is 350-500℃, calcination time is 3.0-5.0 hours.

22. The use of the catalyst according to any one of claims 1-8 in the hydrotreating of residual oil.

23. The application according to claim 22, characterized in that, In this application, the catalyst is used as a hydrodenitrification catalyst; the hydrotreating conditions are as follows: reaction temperature 300-450℃, reaction pressure 12-25 MPa, and liquid hourly space velocity 0.05-0.6 h⁻¹. -1 .

24. The application according to claim 23, characterized in that, In this application, the catalyst is used as a hydrodenitrification catalyst; the hydrotreating conditions are as follows: reaction temperature 350-420℃, reaction pressure 15-22 MPa, and liquid hourly space velocity 0.1-0.4 h⁻¹. -1 .

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