Alumina carrier, method for preparing the same, and use thereof

Abstract

The application provides an alumina carrier and a preparation method and application thereof, and the preparation method comprises the following steps: step 1, subjecting isobutene-maleic anhydride copolymer to an ammonolysis reaction; step 2, mixing the mixture obtained in step 1 with hydrated alumina; step 3, mixing the mixture obtained in step 2 with an aqueous crosslinking agent solution, shaping, drying, and calcining to obtain the alumina carrier. The preparation method is simple, low in cost, and friendly to the environment in the preparation process, and the prepared alumina carrier has a large pore size and pore volume and high mechanical strength. The prepared alumina carrier can be used for a residual oil hydroprocessing active protective agent and a hydrodemetallization catalyst.

Description

Technical Field

[0001] This invention relates to the field of alumina support preparation, and particularly to an alumina support, its preparation method, and its application. Background Technology

[0002] Currently, with the increasing heavy and degraded quality of global petroleum resources, there is an urgent need to develop clean and efficient heavy oil processing technologies. Hydrogenation is the most effective technology for processing heavy and residual oil feedstocks. Through hydrogenation, most metallic impurities and sulfur can be removed, while the carbon residue value can be reduced, improving the quality of heavy oil and making further efficient and clean processing possible. The combination of heavy and residual oil hydrotreating with heavy oil catalytic cracking can not only maximize the conversion of low-value and environmentally polluting residual oil and significantly increase the yield of light oil, but also obtain high-value-added, high-quality clean oil products. This technology combination has become a core technology for refining enterprises processing sulfur-containing crude oil to improve economic efficiency.

[0003] Metals such as Na, Ca, Ni, and V deposited on hydrotreating catalysts in heavy oil can cause permanent poisoning, a crucial factor to consider in the heavy oil hydrotreating process. Active protective agents and hydrodemetallizing catalysts in hydrotreating are key technologies in the heavy oil hydrotreating process. Their main function is to remove most of the Ni and V metal impurities from the feedstock, protecting downstream desulfurization (HDS) and denitrification (HDN) catalysts, while also possessing a certain desulfurization capacity. Both types of catalysts need not only excellent metal removal capabilities but also high metal impurity tolerance. Since most metal impurities in residual oil are found in gums and asphaltenes, which are the largest, most structurally complex, and most polar components in petroleum, they exhibit significant diffusion resistance. Demetallizing agents are constrained by the mass transfer and diffusion efficiency of the carrier, easily leading to pore blockage, severely uneven distribution of removed impurities, and limited metal tolerance. All of these factors result in significant waste of internal catalyst space, preventing the maximization of individual catalyst efficiency. Therefore, both types of catalysts must possess large pore volume, pore size, and good pore permeability to facilitate the diffusion, reaction, and deposition of macromolecular substances such as asphaltenes containing metallic impurities in residual oil feedstock. One solution is to use macroporous alumina supports. During the reaction, the large pores with a diameter of over 100 nm provide channels for the diffusion of macromolecular reactants, promoting the diffusion and deposition of impurities into the internal pores of the catalyst, thereby giving the catalyst high demetallization activity and high impurity tolerance.

[0004] To obtain alumina carrier materials with macroporous structures, researchers have employed methods such as pore expanders and hydrothermal treatment to achieve this structure. There is a considerable body of literature on the synthesis of macroporous alumina materials using pore expanders, which can be categorized into two types based on the type of pore expander: hard pore expanders and soft pore expanders.

[0005] Hard pore-expanding agent methods, represented by activated carbon, can yield relatively good macroporous alumina. US19820384626 discloses a method using carbon black as a pore-expanding agent to obtain macroporous alumina with a pore size distribution of 15–300 nm. However, due to the uneven particle diameter distribution of carbon black, it is difficult to prepare macroporous alumina with a concentrated pore size distribution. CN201410347665.X discloses a method for preparing macroporous, high-strength alumina by adding pore-expanding agents such as polyacrylamide, polyvinyl alcohol, alkyl cellulose, guar gum powder, and starch to obtain a macroporous alumina carrier. The amount of pore-expanding agent used accounts for 10%–30% of the alumina. Although hard pore-expanding agent methods can yield relatively good macroporous alumina carriers, the amount of pore-expanding agent used is preferably greater than 20%, which leads to a significant increase in processing costs. Furthermore, the decomposition of a large amount of pore-expanding agent does not meet the requirements of low-carbon and environmentally friendly development.

[0006] CN102441437B discloses a method for co-expanding pores using hydrothermal heating and a pore-expanding agent to prepare an alumina carrier with a macroporous structure. Through hydrothermal assisted pore-expanding, the amount of pore-expanding agent can be reduced to 3% to 10%, but the auxiliary hydrothermal heating results in increased energy consumption.

[0007] CN100388980C discloses a method for preparing macroporous alumina, using polyvinyl alcohol, polypropylene alcohol, and polyethylene glycol as soft pore expanders. By adding 1% polyethylene glycol, the pore volume with a diameter greater than 100 nm accounts for 26.2% of the total pore volume. Soft pore expanders have the advantages of low dosage and good pore-expanding effect; however, the poor solubility of high molecular weight alcohol-based soft pore expanders in water limits their use in expanding ultra-large porosity alumina.

[0008] CN103922373A discloses a method for preparing porous alumina microspheres, comprising the following steps: 1) dissolving a surfactant in deionized water and stirring to form an aqueous phase; 2) mixing a chelating agent, an alumina precursor, and n-octanol and stirring to form an oil phase; 3) adding Span80 and a pore-forming agent to the oil phase and stirring; 4) pouring the clarified oil phase obtained in step 3) into the aqueous phase and continuously stirring to emulsify; 5) vacuum filtering the product obtained in step 4), washing and drying the resulting filter cake to obtain porous alumina microspheres. These microspheres have an internally closed macroporous structure, with a size of 1–100 μm. This invention utilizes a sol-gel process between a pore-forming agent and an emulsion to obtain metal porous microspheres with an internally closed macroporous structure. The porous microspheres are prepared using the principle of phase separation. The internal closed pore size is 50 nm–5 μm. The pore-forming agent is polyvinylpyrrolidone, polyacrylamide, or polyacrylic acid. This invention uses a large number of surfactants, chelating agents, and pore-forming agents, and requires many raw materials and has a complex synthesis process.

[0009] CN104549534B discloses a method for preparing an alumina support, comprising the following steps: first, a neutralization reaction is carried out between an alkaline precipitant aqueous solution and an acidic aluminum salt aqueous solution to obtain a precipitate slurry; then, a water-soluble resin is added to the precipitate slurry and aged using microwave heating; finally, the aged mixture is filtered, washed, dried, and shaped to obtain the final alumina support. The alumina support prepared by this method has a high proportion of pores with a diameter of 10–20 nm, reaching 60%–80% of the total pore volume, while the proportion of macropores is relatively small.

[0010] CN102765737B discloses a mesoporous spherical alumina and a method for preparing the mesoporous spherical alumina using a pore-expanding agent. The method employs an oil column molding process, adding a pore-expanding agent with a guiding function to the alumina sol during preparation. During the molding and aging process of the alumina sol, the presence of the pore-expanding agent creates a large number of mesoporous structures within the alumina spheres. The pore-expanding agent is an organic monomer or a linear polymer. The organic monomer is one of acrylic acid, ammonium acrylate, acrylamide, or allyl alcohol, and the linear polymer is one of polyvinyl alcohol, polyacrylamide, or polyacrylamide. The specific surface area of ​​the resulting mesoporous spherical alumina is 150–300 μm. 2 / g, particle diameter 0.1–5mm, pore volume 0.7–1.5ml / g, pores with a diameter of 2–40nm greater than 97%, bulk density 0.30–0.80g / cm³ 3 The crushing strength is 70–250 N / particle. The mesoporous spherical alumina prepared by this invention using a pore-expanding agent has a relatively concentrated pore diameter, and the proportion of macropores >100 nm is very small overall, making it unsuitable as a support for heavy oil or residue oil hydrogenation catalysts.

[0011] CN110394197A discloses an ordered hierarchical porous alumina support, its preparation method, and its application. The preparation method includes the following steps: first, a soft template agent, a soluble aluminum salt, a binder, and a precipitant are mixed together to form a supersol-polymerized micelle; then, a hard template agent is mixed with the supersol-polymerized micelles for in-situ synthesis to obtain secondary nano-self-assembled aluminum hydroxide; finally, the secondary nano-self-assembled aluminum hydroxide is washed with water and dried, followed by calcination to obtain the ordered hierarchical porous alumina support. This preparation method is exceptionally complex and requires excessively large dosages, leading to high costs, high energy consumption during calcination, and high carbon emissions. Furthermore, the hard template agent used in this method introduces other elemental impurities into the alumina support, severely affecting its physical properties.

[0012] In summary, the existing macroporous alumina carrier preparation technology has the following problems: (1) When alumina is formed, acidic substances such as nitric acid and acetic acid are often added as adhesives, resulting in small pore volume and pore size of the alumina carrier; (2) A large amount of organic / inorganic pore expanders are added, which generates a large amount of greenhouse gases and harmful gases during the calcination process, resulting in high environmental pressure. This not only increases the carrier preparation cost, but also has a negative impact on the strength of the carrier, and also results in high residual impurities in the carrier; (3) Extrusion aids such as starch and guar gum are required, which increases the carrier preparation cost. Summary of the Invention

[0013] The main objective of this invention is to provide an alumina carrier, its preparation method, and its application, in order to overcome the shortcomings of existing macroporous alumina carriers, such as insufficient pore size, complex preparation methods, and high costs.

[0014] To achieve the above objectives, the present invention provides a method for preparing an alumina support, comprising the following steps:

[0015] Step 1: The isobutylene-maleic anhydride copolymer undergoes ammonolysis.

[0016] Step 2: Mix the mixture obtained in Step 1 with hydrated alumina;

[0017] Step 3: Mix the mixture obtained in Step 2 with an aqueous solution of a crosslinking agent, shape, dry, and calcine to obtain an alumina carrier.

[0018] In the method for preparing the alumina carrier of the present invention, the number average molecular weight of the isobutylene-maleic anhydride copolymer is 6,000-400,000.

[0019] The method for preparing the alumina carrier according to the present invention includes step 1, in which isobutylene-maleic anhydride copolymer is mixed with ammonia water to carry out ammonolysis reaction, wherein the ammonia water is 20% to 100% of the weight of the isobutylene-maleic anhydride copolymer, and the concentration of the ammonia water is 20-40w.

[0020] The method for preparing the alumina carrier according to the present invention, wherein the hydrated alumina is selected from at least one of gibbsite, boehmite, pseudoboehmite, and amorphous aluminum hydroxide.

[0021] In the method for preparing the alumina carrier of the present invention, the amount of the isobutylene-maleic anhydride copolymer added is 1.0%-10.0% of the weight of the hydrated alumina.

[0022] The method for preparing the alumina carrier according to the present invention, wherein the crosslinking agent is an aluminum ion salt.

[0023] In the method for preparing the alumina carrier of the present invention, the amount of crosslinking agent added is 0.1% to 10.0% of the weight of the isobutylene-maleic anhydride copolymer.

[0024] The method for preparing the alumina carrier according to the present invention includes a drying temperature of 100-120°C and a drying time of 0.5-6 hours; and a calcination temperature of 500-1100°C and a calcination time of 0.5-4 hours.

[0025] To achieve the above objectives, the present invention also provides an alumina support obtained by the above preparation method, with a pore volume of 1.5-2.5 ml / g, an average pore size of 30-70 nm, a pore volume with a pore size > 500 nm accounting for 10%-45% of the total pore volume, and a strength > 15 N / mm.

[0026] To achieve the above objectives, the present invention further provides the application of the above-mentioned alumina support in the active protective agent or hydrodemetallization catalyst of residue oil hydrotreating.

[0027] The beneficial effects of this invention are:

[0028] In this invention, the isobutylene-maleic anhydride copolymer after ammonolysis is first mixed with hydrated alumina. The alumina is then coated with a large number of orderly arranged carboxyl groups unique to the structure of the isobutylene-maleic anhydride copolymer, which provides electrostatic repulsion between the coated alumina molecules, increases the intermolecular porosity of the alumina, and makes the mixture uniformly dispersed, which is beneficial to improving the lateral pressure strength of the carrier. Then, a crosslinking agent mixed with deionized water is added to the mixture of the isobutylene-maleic anhydride copolymer and hydrated alumina, so that the isobutylene-maleic anhydride copolymer undergoes a crosslinking reaction in the gaps between the alumina powder, which plays a bonding role and expands the pores during the calcination process. Detailed Implementation

[0029] The technical solution of the present invention is described in detail below. The following embodiments are implemented under the premise of the technical solution of the present invention, and a detailed implementation process is given. However, the protection scope of the present invention is not limited to the following embodiments. In the following embodiments, structures or experimental methods without specific conditions are generally performed under conventional conditions. % unless otherwise specified are by weight.

[0030] This invention provides a method for preparing an alumina support, comprising the following steps:

[0031] Step 1: The isobutylene-maleic anhydride copolymer undergoes ammonolysis.

[0032] Step 2: Mix the mixture obtained in Step 1 with hydrated alumina;

[0033] Step 3: Mix the mixture obtained in Step 2 with an aqueous crosslinking agent, shape, dry, and calcine to obtain an alumina carrier.

[0034] This invention first involves ammonolyzing an isobutylene-maleic anhydride copolymer, then mixing the ammonolyzed isobutylene-maleic anhydride copolymer with hydrated alumina. The alumina is encapsulated by the numerous orderly arranged carboxyl groups inherent in the structure of the isobutylene-maleic anhydride copolymer, which provide electrostatic repulsion between the encapsulated alumina molecules, increasing the intermolecular porosity and dispersing the hydrated alumina, thus improving the lateral compressive strength of the carrier. Furthermore, a mixture of a crosslinking agent and water is mixed with the mixture of the ammonolyzed isobutylene-maleic anhydride copolymer and hydrated alumina, causing the isobutylene-maleic anhydride copolymer to undergo a crosslinking reaction within the gaps of the alumina powder, acting as a binder and expanding the pores during calcination.

[0035] The preparation method of this invention is simple, low-cost, and environmentally friendly. The resulting alumina support has a large pore size and volume, and high mechanical strength. The prepared alumina support can be used as an active protective agent and a hydrodemetallization catalyst in the hydrotreating of residual oil.

[0036] In one embodiment, the isobutylene-maleic anhydride copolymer of the present invention is an alternating copolymer; in another embodiment, the number-average molecular weight of the isobutylene-maleic anhydride copolymer is 6,000-400,000.

[0037] In one embodiment, ammonia is used as the reagent for ammonolysis of the isobutylene-maleic anhydride copolymer; that is, the isobutylene-maleic anhydride copolymer is mixed with ammonia to carry out the ammonolysis reaction. In another embodiment, the amount of ammonia added is 20% to 100% of the weight of the isobutylene-maleic anhydride copolymer, and the concentration of the ammonia is 20-40 wt%. Mixing the isobutylene-maleic anhydride copolymer with hydrated alumina after ammonolysis results in a more uniform mixture of the isobutylene-maleic anhydride copolymer and alumina.

[0038] This invention does not particularly limit the conditions of the ammonolysis reaction; for example, it can be carried out at room temperature (20-30°C). The mixture after ammonolysis is mixed with hydrated alumina to disperse the hydrated alumina. This invention does not particularly limit the type of hydrated alumina. In one embodiment, the hydrated alumina is selected from at least one of gibbsite, boehmite, pseudoboehmite, and amorphous aluminum hydroxide; more preferably, pseudoboehmite. This invention can adjust the amount of isobutylene-maleic anhydride copolymer and hydrated alumina according to the pore size requirements of the alumina carrier to be prepared. In one embodiment, the amount of isobutylene-maleic anhydride copolymer added is 1.0%-10.0% of the weight of hydrated alumina, more preferably 3.0%-7.0%, and most preferably 3.0%-3.5%, which can effectively disperse the alumina.

[0039] Then, the dispersed hydrated alumina is mixed with an aqueous crosslinking agent solution, shaped, dried, and calcined to obtain an alumina carrier.

[0040] The crosslinking agent aqueous solution is a mixture of crosslinking agent and water. In one embodiment, the crosslinking agent is an aluminum ion salt, such as aluminum sulfate, aluminum nitrate, or aluminum chloride, preferably aluminum sulfate. The present invention does not particularly limit the concentration of the crosslinking agent aqueous solution. In one embodiment, the amount of crosslinking agent added is 0.1% to 10.0% of the weight of the isobutylene-maleic anhydride copolymer, more preferably 0.5% to 5.0%, and most preferably 1.0% to 1.5%. The crosslinking agent is mainly used to induce a crosslinking reaction in the isobutylene-maleic anhydride copolymer within the alumina interstices. The crosslinked copolymer forms interconnected channels during subsequent calcination, thus playing a role in pore expansion.

[0041] In one embodiment, the drying temperature is 100–120°C and the time is 0.5–6 hours; the calcination temperature is 500–1100°C and the time is 0.5–4 hours.

[0042] The preparation method of this invention is mild and can be carried out entirely at room temperature and pressure. The carrier molding process is stable and efficient, and highly adaptable to various equipment. The alumina carrier prepared by this method has a pore volume of 1.5-2.5 ml / g, an average pore size of 30-70 nm, and pores with a diameter >500 nm accounting for 10-45% of the total pore volume. The carrier strength is >15 N / mm. Compared with existing alumina carriers, the alumina carrier prepared by this invention has a 30% higher mechanical strength, a pore volume increase of over 10%, and a more than 50% reduction in additive usage, significantly reducing the carrier preparation cost. Furthermore, the isobutylene-maleic anhydride copolymer has a residual ash content of less than 0.5 wt% during calcination, and the emission of harmful gases is reduced by more than 50% compared to existing technologies, with CO2 emissions reduced by more than 50%, making it environmentally friendly.

[0043] The alumina support prepared by this invention can be used as an active protective agent or a hydrodemetallization catalyst for residual oil hydrotreating.

[0044] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0045] Example 1

[0046] 20g of isobutylene-maleic anhydride copolymer (number average molecular weight 6000) was weighed and then 32g of 25wt% ammonia solution was added for ammonolysis. After complete ammonolysis, 564g of macroporous pseudoboehmite dry adhesive powder (dry basis content 71.0wt%) produced by Shandong Binzhou Juchuang Company was weighed and mixed evenly with the ammonolyzed isobutylene-maleic anhydride copolymer. 0.3g of crosslinking agent aluminum sulfate and 750g of deionized water were weighed and mixed, then added to the mixture of alumina and isobutylene-maleic anhydride copolymer, kneaded into a plastic body, and then extruded into clover-shaped carrier wet strips with a diameter of 1.4mm on an extruder. The wet strips were dried at 120℃ for 3.0 hours and then placed in a high-temperature calcination furnace and kept at 950℃ for 3 hours to obtain carrier A. Its physicochemical properties are listed in Table 1.

[0047] Example 2

[0048] 12g of isobutylene-maleic anhydride copolymer (number average molecular weight 200,000) was weighed and then 50g of 25wt% ammonia solution was added for ammonolysis. After complete ammonolysis, 588g of macroporous pseudoboehmite dry adhesive powder (dry basis content 68.0wt%) produced by Shandong Linqu Heng Hui Co., Ltd. was weighed and mixed evenly with the ammonolyzed isobutylene-maleic anhydride copolymer. 1g of crosslinking agent aluminum sulfate and 700g of deionized water were weighed and mixed, then added to the mixture of alumina and isobutylene-maleic anhydride copolymer, kneaded into a plastic body, and then extruded into clover-shaped carrier wet strips with a diameter of 1.4mm on an extruder. The wet strips were dried at 120℃ for 3.0 hours and then placed in a high-temperature calcination furnace and kept at 900℃ for 4 hours to obtain carrier B. Its physicochemical properties are listed in Table 1.

[0049] Example 3

[0050] Weigh 5g of isobutylene-maleic anhydride copolymer (number average molecular weight 300,000), then add 15g of 25wt% ammonia water for ammonolysis. After complete ammonolysis, weigh 556g of macroporous pseudoboehmite dry adhesive powder (dry basis content 72.0wt%) produced by Shanxi Juhua Company, and mix it evenly with the ammonolyzed isobutylene-maleic anhydride copolymer. Weigh 0.1g of crosslinking agent aluminum sulfate and 600g of deionized water, mix them, and then add them to the mixture of alumina and isobutylene-maleic anhydride copolymer. Knead the mixture into a plastic body, and then extrude it into a clover-shaped carrier wet strip with a diameter of 1.4mm on an extruder. Dry the wet strip at 100℃ for 2.5 hours, and then place it in a high-temperature calcination furnace and keep it at 920℃ for 4 hours to obtain carrier C. Its physicochemical properties are listed in Table 1.

[0051] Example 4

[0052] 25g of isobutylene-maleic anhydride copolymer (number average molecular weight 200,000) was weighed and then 65g of 25wt% ammonia solution was added for ammonolysis. After complete ammonolysis, 556g of macroporous pseudoboehmite dry adhesive powder (dry basis content 72.0wt%) produced by Shanxi Juhua Company was weighed and mixed evenly with the ammonolyzed isobutylene-maleic anhydride copolymer. 2.5g of crosslinking agent aluminum sulfate and 700g of deionized water were weighed and mixed, then added to the mixture of alumina and isobutylene-maleic anhydride copolymer, kneaded into a plastic body, and then extruded into clover-shaped carrier wet strips with a diameter of 1.4mm on an extruder. The wet strips were dried at 110℃ for 4.5 hours and then placed in a high-temperature calcination furnace and kept at 870℃ for 4 hours to obtain carrier D. Its physicochemical properties are listed in Table 1.

[0053] Comparative Examples 1-4: Alumina supports prepared using existing techniques.

[0054] Comparative Example 1

[0055] The difference from Example 1 is that 20g of polyacrylamide disclosed in CN104084182B (national drug procurement, national drug code 30503770) was added as a pore expander. Otherwise, it is the same as Example 1, and the carrier G is obtained. Its physicochemical properties are listed in Table 1.

[0056] Comparative Example 2

[0057] The difference from Example 1 is that 20g of carbon black powder (particle size 20-40μm) disclosed in CN102441437B was added as a pore-expanding agent. Otherwise, the same as in Example 1 was used to obtain carrier H, the physicochemical properties of which are listed in Table 1.

[0058] Comparative Example 3

[0059] The difference from Example 1 is that 20g of the water-soluble resin (water-soluble polyacrylic acid resin, trade name: carbomer u20) disclosed in CN104549534B was added as a pore expander. Otherwise, it is the same as Example 1, and the carrier I is obtained. Its physicochemical properties are listed in Table 1.

[0060] Comparative Example 4

[0061] The difference from Example 1 is that 20g of polyisobutylene triethanolamine maleate (self-made, number average molecular weight 500) disclosed in CN1296136C was added as an organic pore expander. Otherwise, it is the same as Example 1, and the carrier J is obtained. Its physicochemical properties are listed in Table 1.

[0062] Table 1. Physicochemical properties of the carriers in the examples and comparative examples.

[0063]

[0064] As shown in Table 1, the support prepared using the comparative example method has no pore size distribution >500 nm. Compared with the comparative example, the alumina support prepared using the method of the present invention has advantages such as large pore volume, large average pore size, high lateral pressure strength, low impurity residue, and a high proportion of pores >500 nm in the alumina support. Therefore, the alumina support prepared by the method of the present invention can better provide channels for the diffusion of macromolecular reactants and promote the diffusion and deposition of impurities into the internal pores of the catalyst. In addition, compared with the comparative example, the method of the present invention reduces the amount of isobutylene-maleic anhydride copolymer additive added, and the mass ratio of the total additive to the mass of alumina is significantly reduced, effectively reducing the support preparation cost, simplifying the preparation process, and greatly reducing the emission of greenhouse gases and harmful gases during the preparation process.

[0065] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing an alumina carrier, characterized in that, Includes the following steps: Step 1: The isobutylene-maleic anhydride copolymer undergoes ammonolysis. Step 2: Mix the mixture obtained in Step 1 with hydrated alumina; Step 3: Mix the mixture obtained in Step 2 with an aqueous solution of a crosslinking agent, shape, dry, and calcine to obtain an alumina carrier; In this process, isobutylene-maleic anhydride copolymer is mixed with ammonia water for ammonolysis reaction, wherein the ammonia water accounts for 20% to 100% of the weight of the isobutylene-maleic anhydride copolymer and the concentration of the ammonia water is 20-40w.

2. The method for preparing the alumina carrier according to claim 1, characterized in that, The number-average molecular weight of the isobutylene-maleic anhydride copolymer is 6,000-400,000.

3. The method for preparing the alumina carrier according to claim 1, characterized in that, The hydrated alumina is selected from at least one of gibbsite, boehmite, pseudoboehmite, and amorphous aluminum hydroxide.

4. The method for preparing the alumina carrier according to claim 1, characterized in that, The amount of the isobutylene-maleic anhydride copolymer added is 1.0%-10.0% of the weight of the hydrated alumina.

5. The method for preparing the alumina carrier according to claim 1, characterized in that, The crosslinking agent is an aluminum ion salt.

6. The method for preparing the alumina carrier according to claim 1, characterized in that, The amount of crosslinking agent added is 0.1% to 10.0% of the weight of the isobutylene-maleic anhydride copolymer.

7. The method for preparing the alumina carrier according to claim 1, characterized in that, The drying temperature is 100~120℃, and the drying time is 0.5~6 hours; the calcination temperature is 500~1100℃, and the calcination time is 0.5~4 hours.

8. The alumina support obtained by the preparation method according to any one of claims 1-7, characterized in that, The pore volume is 1.5-2.5 ml / g, the average pore size is 30-70 nm, the pore volume with a pore size > 500 nm accounts for 10%-45% of the total pore volume, and the strength is > 15 N / mm.

9. The application of the alumina support according to claim 8 in the active protective agent or hydrodemetallization catalyst for residual oil hydrotreating.

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