Alumina carrier as well as preparation method and application thereof

Abstract

The invention provides an alumina carrier as well as a preparation method and application thereof. The preparation method comprises the following steps: step 1, performing ammonolysis reaction on an isobutylene-maleic anhydride copolymer; step 2, mixing the mixture obtained in the step 1 with hydrated alumina; and step 3, mixing the mixture obtained in the step 2 with a cross-linking agent aqueous solution, molding, drying, and roasting to obtain the alumina carrier. The preparation method is simple and low in cost, the preparation process is environmentally friendly, and the prepared alumina carrier is large in pore diameter and pore volume and high in mechanical strength. The prepared alumina carrier can be used for a residual oil hydrotreating active protective agent and a hydrodemetallization catalyst.

Description

Technical Field

[0001] The present invention relates to the field of alumina carrier preparation, and in particular to an alumina carrier and a preparation method and application thereof. Background Art

[0002] At present, with the increasing heaviness and inferiority of oil resources worldwide, there is an urgent need to develop clean and efficient heavy oil processing technology. Hydrogenation is the most effective heavy and residual oil raw material processing technology. Through hydrogenation, most of the metal impurities and sulfur can be removed, while the residual carbon value can be reduced, the quality of heavy oil can be improved, and further efficient and clean processing can be provided. The technical combination of heavy and residual oil hydroprocessing and heavy oil catalytic cracking can not only maximize the conversion of residual oil with low utilization value and easy to cause environmental pollution, and greatly increase the yield of light oil; it can also obtain clean oil products with high added value and high quality. This technical combination has become the core technology for sulfur-containing crude oil processing and refining enterprises to improve economic benefits.

[0003] The deposition of metals such as Na, Ca, Ni, and V in heavy oil on the hydrogenation catalyst will cause permanent poisoning, which is an important factor to be considered in the heavy oil hydrogenation process. The active protective agent in the hydroprocessing protective agent and the hydrodemetallization catalyst are the key technologies in the heavy oil hydroprocessing process. Their main function is to remove most of the metal impurities such as Ni and V in the raw materials, protect the downstream desulfurization (HDS) and denitrification (HDN) catalysts, and have a certain desulfurization capacity. The above two types of catalysts need to have not only good metal removal ability, but also high metal impurity tolerance. Since most of the metal impurities in the residual oil exist in colloids and asphaltene, and colloids and asphaltene are the largest molecular weight, most complex structure, and strongest polarity in the petroleum components, the diffusion resistance is large. The demetallization agent is restricted by the mass transfer and diffusion efficiency of the carrier, and is prone to pore blockage, the deposition distribution of the impurities removed is seriously uneven, and the metal tolerance capacity is limited. All of the above cause serious waste of the internal space of the catalyst, and the efficiency of a single catalyst cannot be maximized. Therefore, these two types of catalysts must have a large pore volume, pore diameter and good pore permeability to facilitate the diffusion, reaction and deposition of macromolecular substances such as asphaltene containing metal impurities in the residual oil raw material. One solution is to use a macroporous alumina carrier. During the reaction process, macropores with a pore diameter of more than 100nm provide channels for the diffusion of macromolecular reaction substances, promote the diffusion and deposition of impurities into the internal pores of the catalyst, and thus make the catalyst have high demetallization activity and high impurity tolerance.

[0004] In order to obtain alumina carrier materials with macroporous structures, researchers have obtained macroporous alumina by using pore expanders, hydrothermal treatment and other methods. There are many related literatures on the synthesis of macroporous alumina materials by pore expanders. According to the different types of pore expanders, they can be divided into two methods: hard pore expanders and soft pore expanders.

[0005] The hard pore expander method represented by activated carbon can obtain better macroporous alumina. US19820384626 discloses a carbon black as a pore expander, which can obtain macroporous alumina with a pore size distribution of 15 to 300 nm. However, due to the uneven distribution of the particle diameter of carbon black, it is difficult to prepare macroporous alumina with a concentrated pore size distribution. CN201410347665.X discloses a method for preparing alumina with large pore volume and high strength. By adding pore expanders such as polyacrylamide, polyvinyl alcohol, alkyl cellulose, sesbania powder, starch, etc., an alumina carrier containing macropores is obtained, and the amount of the pore expander accounts for 10% to 30% of the alumina. Although the hard pore expander method can obtain a better macroporous alumina carrier, the amount of the pore expander is preferably greater than 20%, which leads to a significant increase in processing costs, and the decomposition of a large amount of pore expanders does not meet the development requirements of low-carbon and environmental protection.

[0006] CN102441437B discloses a method for pore expansion using hydrothermal and pore expander to prepare an alumina carrier having a macroporous structure. Through the hydrothermal auxiliary pore expansion effect, the amount of pore expander can be reduced to 3% to 10%, but the auxiliary hydrothermal causes an increase in energy consumption.

[0007] CN100388980C discloses a method for preparing macroporous alumina, wherein polyvinyl alcohol, polypropylene alcohol and polyethylene glycol soft pore expanders are used for pore expansion, and by adding 1% polyethylene glycol, the pore volume with a pore diameter greater than 100 nm accounts for 26.2% of the total pore volume. The soft pore expander has the advantages of low dosage and good pore expansion effect, but the alcohol soft pore expander with a higher molecular weight has poor solubility in water, which limits its use in expanding ultra-macroporous alumina.

[0008] CN103922373A discloses a method for preparing porous alumina microspheres, comprising the following steps: 1) dissolving a surfactant in deionized water and stirring as a water phase; 2) mixing a chelating agent, an alumina precursor and n-octanol and stirring as an oil phase; 3) adding Span80 and a porogen to the oil phase and stirring; 4) pouring the clarified oil phase obtained in step 3) into the water phase and continuously stirring and emulsifying; 5) vacuum filtering the product obtained in step 4), washing the filter cake and drying it to obtain porous alumina microspheres. The microspheres have an internal closed macroporous structure, and the microsphere size is 1 to 100 μm. The invention uses a porogen and a sol-gel process in an emulsion to obtain a metal porous microsphere with an internal closed macroporous structure. The porous microspheres are prepared using the phase separation principle. The internal closed pore size is 50 nm to 5 μm. The porogen is polyvinyl pyrrolidone, polyacrylamide or polyacrylic acid. The invention uses a large amount of surfactants, chelating agents, and porogens, requires a lot of raw materials, and has a complicated synthesis process.

[0009] CN104549534B discloses a method for preparing an alumina carrier, comprising the following contents: firstly, neutralizing an alkaline precipitant aqueous solution with an acidic aluminum salt aqueous solution to obtain a precipitation slurry; then, adding a water-soluble resin to the precipitation slurry and subjecting it to an aging treatment by microwave heating; finally, filtering, washing, drying, and molding the aged mixture to obtain a final alumina carrier. The alumina carrier prepared by the method has a large proportion of pores of 10 to 20 nm in the total pore volume, reaching 60% to 80%, and a small proportion of macropores.

[0010] CN102765737B provides a mesoporous spherical alumina and a method for preparing the mesoporous spherical alumina by using a pore expander. The oil column molding method is used to add a pore expander with a guiding function to the aluminum sol during the preparation of the aluminum sol. During the molding and aging process of the aluminum sol, a large number of mesoporous structures are produced in the alumina balls due to the presence of the pore expander with a guiding function. The pore expander is an organic monomer or a linear polymer. The organic monomer is one of acrylic acid, ammonium acrylate, acrylamide, and allyl alcohol. The linear polymer is one of polyvinyl alcohol, polyacrylamide, polyacrylamide, and polypropylene alcohol. The specific surface area of ​​the mesoporous spherical alumina is 150 to 300 m 2 / g, particle diameter 0.1 ~ 5mm, pore volume 0.7 ~ 1.5ml / g, pore diameter 2 ~ 40nm pores greater than 97%, bulk density 0.30 ~ 0.80g / cm 3 The crushing strength is 70-250N / grain. The mesoporous spherical alumina prepared by the pore-expanding agent in the invention has relatively concentrated pore diameters, and the overall proportion of macropores > 100nm is very small, so it is not suitable as a carrier for heavy oil or residual oil hydrogenation catalysts.

[0011] CN110394197A discloses an ordered hierarchical pore alumina carrier and its preparation method and application. The preparation method of the alumina carrier comprises the following steps: firstly, a soft template, a soluble aluminum salt, a binder and a precipitant are mixed together to form a super-solubilized micelle by self-assembly; then, a hard template is mixed with the super-solubilized micelle to perform an in-situ synthesis reaction to obtain a secondary nano self-assembled aluminum hydroxide; then, the secondary nano self-assembled aluminum hydroxide is sequentially washed and dried, and then calcined to obtain an ordered hierarchical pore alumina carrier. The preparation method is extremely complicated, and the required additive amount is too large, resulting in excessive cost, energy consumption and carbon emissions during the calcination process. At the same time, the hard template used in this method will introduce other element impurities into the alumina carrier, which seriously affects the physical properties of the carrier.

[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 need to be added as peptizing agents, which leads to small pore volume and pore size of the alumina carrier; (2) A large amount of organic / inorganic pore expanders are added, and a large amount of greenhouse gases and harmful gases are generated during the roasting process, which puts great pressure on the environmental protection. This not only increases the cost of carrier preparation, but also has a negative impact on the strength of the carrier and also leads to a high content of impurities in the carrier; (3) Extrusion aids such as starch and sesbania powder need to be added, which increases the cost of carrier preparation. Summary of the invention

[0013] The main purpose of the present invention is to provide an alumina carrier and a preparation method and application thereof, so as to overcome the defects of the existing macroporous alumina carrier, such as the pore size does not meet the requirements, the preparation method is complicated, and the cost is high.

[0014] In order to achieve the above object, the present invention provides a method for preparing an alumina carrier, comprising the following steps:

[0015] Step 1, subjecting the isobutylene-maleic anhydride copolymer to an aminolysis reaction;

[0016] Step 2, mixing the mixture obtained in step 1 with hydrated alumina;

[0017] Step 3, mixing the mixture obtained in step 2 with an aqueous solution of a crosslinking agent, forming, drying, and calcining 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 6000-400000.

[0019] The preparation method of the alumina carrier of the present invention, wherein in step 1, the isobutylene-maleic anhydride copolymer is mixed with ammonia water for aminolysis reaction, 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 an alumina carrier of the present invention, wherein the hydrated alumina is selected from at least one of gibbsite, boehmite, pseudo-boehmite, 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 an alumina carrier of the present invention, wherein the cross-linking agent is an aluminum ion salt.

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

[0024] The method for preparing the alumina carrier of the present invention comprises the following steps: the drying temperature is 100-120° C., and the drying time is 0.5-6 hours; the calcination temperature is 500-1100° C., and the calcination time is 0.5-4 hours.

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

[0026] In order to achieve the above object, the present invention further provides the use of the above alumina carrier in a residual oil hydroprocessing active protective agent or a hydrodemetallization catalyst.

[0027] Beneficial effects of the present invention:

[0028] The invention first mixes the isobutylene-maleic anhydride copolymer after ammonolysis with hydrated alumina, and uses a large number of orderly arranged carboxyl groups peculiar to the structure of the isobutylene-maleic anhydride copolymer to wrap the alumina, so that the wrapped alumina provide electrostatic repulsion to each other, increase the gap between alumina molecules, and make the mixture dispersed evenly, which is beneficial to improve the lateral pressure strength of the carrier; then, a crosslinking agent is mixed with deionized water and added to the mixture of the isobutylene-maleic anhydride copolymer after ammonolysis and the hydrated alumina, so that the isobutylene-maleic anhydride copolymer undergoes a crosslinking reaction in the gaps between alumina powders, plays a bonding role, and plays a pore expansion effect during the calcination process. DETAILED DESCRIPTION

[0029] The technical scheme of the present invention is described in detail below. The following implementation modes are implemented on the premise of the technical scheme 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 implementation modes. In the following implementation modes, structures or experimental methods without specifying specific conditions are usually based on conventional conditions, and unspecified % are % by weight.

[0030] The present invention provides a method for preparing an alumina carrier, comprising the following steps:

[0031] Step 1, subjecting the isobutylene-maleic anhydride copolymer to an aminolysis reaction;

[0032] Step 2, mixing the mixture obtained in step 1 with hydrated alumina;

[0033] Step 3, mixing the mixture obtained in step 2 with an aqueous solution of a crosslinking agent, forming, drying, and calcining to obtain an alumina carrier.

[0034] The present invention firstly performs ammonolysis on an isobutylene-maleic anhydride copolymer, then mixes the ammonolyzed isobutylene-maleic anhydride copolymer with hydrated alumina, and uses a large number of orderly arranged carboxyl groups that are unique to the structure of the isobutylene-maleic anhydride copolymer to wrap the alumina, and allows the wrapped alumina to provide electrostatic repulsion to each other, thereby increasing the gaps between alumina molecules, playing a role in dispersing the hydrated alumina, and facilitating the improvement of the carrier lateral pressure strength. In addition, a mixture of a crosslinking agent and water is mixed with the mixture of the ammonolyzed isobutylene-maleic anhydride copolymer and hydrated alumina, so that the isobutylene-maleic anhydride copolymer undergoes a crosslinking reaction in the gaps between the alumina powders, plays a bonding role, and plays a pore expansion effect during the calcination process.

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

[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, the reagent for the aminolysis of the isobutylene-maleic anhydride copolymer is ammonia water, that is, the isobutylene-maleic anhydride copolymer is mixed with ammonia water for aminolysis reaction. In another embodiment, the amount of ammonia water added in the present invention is 20% to 100% of the weight of the isobutylene-maleic anhydride copolymer, and the concentration of ammonia water is 20-40w%. After the isobutylene-maleic anhydride copolymer is aminolyzed, it is mixed with hydrated aluminum oxide, which can make the isobutylene-maleic anhydride copolymer and aluminum oxide mixed more uniformly.

[0038] The present invention does not particularly limit the conditions of the ammonolysis reaction, for example, it can be carried out at room temperature of 20-30°C. The mixture after ammonolysis is mixed with hydrated alumina to disperse the hydrated alumina. The present 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, pseudo-boehmite and amorphous aluminum hydroxide; more preferably pseudo-boehmite. The present invention can adjust the dosage relationship 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 the hydrated alumina, more preferably 3.0%-7.0%, and most preferably 3.0%-3.5%, which can well disperse the alumina.

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

[0040] The crosslinking agent aqueous solution is a mixture of a crosslinking agent and water. In one embodiment, the crosslinking agent is an aluminum ion salt, such as aluminum sulfate, aluminum nitrate, aluminum chloride, etc., preferably aluminum sulfate. The present invention does not particularly limit the concentration of the crosslinking agent aqueous solution. In one embodiment, the amount of the crosslinking agent added is 0.1 to 10.0% by 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 for the crosslinking reaction of the isobutylene-maleic anhydride copolymer in the gap of alumina. The crosslinked copolymer forms interconnected channels in the subsequent calcination process, which plays a role in expanding the pores.

[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 the present invention has mild conditions and can be carried out at normal temperature and pressure throughout the process. The carrier molding process is stable and efficient, and has strong adaptability to equipment. The pore volume of the alumina carrier prepared by the method of the present invention is 1.5-2.5 ml / g, the average pore diameter is 30-70 nm, the pore volume with a pore diameter of more than 500 nm accounts for 10-45% of the total pore volume, and the carrier strength is more than 15 N / mm. Compared with the alumina carrier of the prior art, the mechanical strength of the alumina carrier prepared by the present invention is increased by 30%, the pore volume is increased by more than 10%, the amount of additives is reduced by more than 50%, and the cost of carrier preparation is greatly reduced. In addition, the residual ash content of the isobutylene-maleic anhydride copolymer during the roasting process is less than 0.5wt%, the harmful gas emissions generated are reduced by more than 50% compared with the prior art, and the CO2 emissions are reduced by more than 50%, which is environmentally friendly.

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

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

[0045] Example 1

[0046] Weigh 20g of isobutylene-maleic anhydride copolymer (number average molecular weight is 6000), then add 32g of 25wt% ammonia water for aminolysis, after complete aminolysis, weigh 564g of macroporous pseudo-boehmite dry rubber powder (dry basis content 71.0wt%) produced by Shandong Binzhou Juchuang Company, and mix it evenly with the isobutylene-maleic anhydride copolymer after aminolysis; weigh 0.3g of crosslinking agent aluminum sulfate and 750g of deionized water, add the mixture of aluminum oxide and isobutylene-maleic anhydride copolymer, knead into a plastic body, and then extrude into a four-leaf clover-shaped carrier wet strip with a diameter of 1.4mm on an extruder. The wet strip is dried at 120°C for 3.0 hours, and then placed in a high-temperature roasting furnace, and constant temperature is 950°C for 3 hours to obtain carrier A, and its physical and chemical properties are listed in Table 1.

[0047] Example 2

[0048] Weigh 12g of isobutylene-maleic anhydride copolymer (number average molecular weight of 200000), then add 50g of 25wt% ammonia water for aminolysis. After complete aminolysis, weigh 588g of macroporous pseudo-boehmite dry rubber powder (dry basis content of 68.0wt%) produced by Shandong Linqu Henghui Company, and mix it evenly with the isobutylene-maleic anhydride copolymer after aminolysis; weigh 1g of crosslinking agent aluminum sulfate and 700g of deionized water, add the mixture of aluminum oxide and isobutylene-maleic anhydride copolymer, knead into a plastic, and then extrude into a four-leaf clover-shaped carrier wet strip with a diameter of 1.4mm on an extruder. The wet strip is dried at 120°C for 3.0 hours, and then placed in a high-temperature roasting furnace, and kept at 900°C for 4 hours to obtain carrier B, whose physical and chemical properties are listed in Table 1.

[0049] Example 3

[0050] Weigh 5g of isobutylene-maleic anhydride copolymer (number average molecular weight of 300000), then add 15g of 25wt% ammonia water for aminolysis. After complete aminolysis, weigh 556g of macroporous pseudo-boehmite dry rubber powder (dry basis content of 72.0wt%) produced by Shanxi Juhua Company, and mix it evenly with the isobutylene-maleic anhydride copolymer after aminolysis; weigh 0.1g of crosslinking agent aluminum sulfate and 600g of deionized water, add the mixture of aluminum oxide and isobutylene-maleic anhydride copolymer, knead into a plastic, and then extrude into a four-leaf clover-shaped carrier wet strip with a diameter of 1.4mm on an extruder. The wet strip is dried at 100°C for 2.5 hours, and then placed in a high-temperature roasting furnace at 920°C for 4 hours to obtain carrier C, whose physicochemical properties are listed in Table 1.

[0051] Example 4

[0052] Weigh 25g of isobutylene-maleic anhydride copolymer (number average molecular weight of 200000), then add 65g of 25wt% ammonia water for aminolysis. After complete aminolysis, weigh 556g of macroporous pseudo-boehmite dry rubber powder (dry basis content of 72.0wt%) produced by Shanxi Juhua Company, and mix it evenly with the isobutylene-maleic anhydride copolymer after aminolysis; weigh 2.5g of crosslinking agent aluminum sulfate and 700g of deionized water, add the mixture of aluminum oxide and isobutylene-maleic anhydride copolymer, knead into a plastic, and then extrude into a four-leaf clover-shaped carrier wet strip with a diameter of 1.4mm on an extruder. The wet strip is dried at 110°C for 4.5 hours, and then placed in a high-temperature roasting furnace at 870°C for 4 hours to obtain carrier D, whose physicochemical properties are listed in Table 1.

[0053] Comparative Examples 1-4 used an alumina carrier prepared using prior art.

[0054] Comparative Example 1

[0055] The difference from Example 1 is that 20 g of polyacrylamide disclosed in CN104084182B (purchased by National Medicines, National Medicines Code 30503770) is added as a pore-enlarging agent. The rest is the same as Example 1 to obtain carrier G, whose physicochemical properties are listed in Table 1.

[0056] Comparative Example 2

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

[0058] Comparative Example 3

[0059] The difference from Example 1 is that 20 g of the water-soluble resin disclosed in CN104549534B (water-soluble polyacrylic acid resin, trade name: Carbomer U20) is added as a pore-enlarging agent, and the rest is the same as Example 1 to obtain a carrier I, whose physicochemical properties are listed in Table 1.

[0060] Comparative Example 4

[0061] The difference from Example 1 is that 20 g of polyisobutylene maleate triethanolamine ester (self-made, number average molecular weight 500) disclosed in CN1296136C is added as an organic pore-enlarging agent. The rest is the same as Example 1 to obtain a carrier J, whose physicochemical properties are listed in Table 1.

[0062] Table 1 Physical and chemical properties of carriers in examples and comparative examples

[0063]

[0064] As shown in Table 1, the carrier prepared by the comparative example method has no pore size distribution > 500nm; compared with the comparative example, the alumina carrier prepared by the method of the present invention has the advantages of large pore volume, large average pore size, high carrier lateral pressure strength, less impurity residue, and a high proportion of pore volume with pore size > 500nm in the alumina carrier. Therefore, the alumina carrier prepared by the method of the present invention can better provide a channel for the diffusion of macromolecular reaction substances 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 the additive isobutylene-maleic anhydride copolymer, and the mass of the total additives accounts for a significantly lower proportion of the mass of alumina, which effectively reduces the cost of carrier preparation, simplifies the preparation process, and greatly reduces the emission of greenhouse gases and harmful gases during the preparation process.

[0065] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing an alumina carrier, characterized in that: The steps include: Step 1, subjecting the isobutylene-maleic anhydride copolymer to an aminolysis 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 solution of a crosslinking agent, forming, drying, and calcining to obtain an alumina carrier.

2. The method for preparing an 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 an alumina carrier according to claim 1, characterized in that: In step 1, the isobutylene-maleic anhydride copolymer is mixed with ammonia water for aminolysis 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%.

4. The method for preparing an alumina carrier according to claim 1, characterized in that: The hydrated aluminum oxide is selected from at least one of gibbsite, boehmite, pseudo-boehmite, and amorphous aluminum hydroxide.

5. The method for preparing an alumina carrier according to claim 1, characterized in that: The addition amount of the isobutylene-maleic anhydride copolymer is 1.0%-10.0% by weight of the hydrated aluminum oxide.

6. The method for preparing an alumina carrier according to claim 1, characterized in that: The cross-linking agent is an aluminum ion salt.

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

8. The method for preparing an alumina carrier according to claim 1, characterized in that: The drying temperature is 100-120° C., and the drying time is 0.5-6 hours; the roasting temperature is 500-1100° C., and the roasting time is 0.5-4 hours.

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

10. Use of the alumina carrier according to claim 9 in a residual oil hydroprocessing active protective agent or a hydrodemetallization catalyst.

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