A method for preparing a large-pore hydro-sodalite alumina carrier

Abstract

The present application relates to the technical field of alumina carrier, in particular to a preparation method of super-large pore hydrogen spheroidal alumina carrier.The preparation method of super-large pore hydrogen spheroidal alumina carrier comprises the following steps: a) mixing nanocellulose and amino silane coupling agent in water to prepare slurry;b) mixing pseudo-boehmite, inorganic strong acid and water, kneading for 20-40 min to obtain initial sol; then stirring the slurry prepared from the initial sol and the solution of basic aluminum chloride for 40-50 min to obtain slurry; forming the slurry to obtain wet gel balls;c) mixing the wet gel balls obtained in step b) with urea solution, and hydrothermal reaction at 110-130 DEG C for 5-7 h; washing with water; drying; and then sintering in an oxygen-containing atmosphere, thus obtaining the super-large pore hydrogen spheroidal alumina carrier.The preparation method of the present application generates a microcrystalline hardening layer of mullite in situ at the interface of the carrier pore wall, thereby maintaining high porosity while improving mechanical strength.

Description

Technical Field

[0001] This invention relates to the field of alumina support technology, and specifically to a method for preparing an ultra-large porous hydrogenated spherical alumina support. Background Technology

[0002] Heavy oil feedstocks contain a large number of gum and asphaltic macromolecules with molecular dynamic diameters reaching tens of nanometers, as well as porphyrin metal complexes such as nickel and vanadium encapsulated within them. Therefore, in the hydrodemetallization (HDM) and hydrodesulfurization (HDS) production of heavy oil, the hydrotreating catalyst must possess an ultraporous structure (pore size > 100 nm) to provide mass transfer channels for these macromolecules and "gold-containing space" for metal deposition. Due to the high requirements for heavy oil hydrotreating catalysts, the performance requirements for the spherical γ-Al2O3 support, which serves as the catalyst framework, are also increased.

[0003] In existing technologies, the preparation of spherical γ-Al₂O₃ supports typically uses boehmite as a precursor, adding polystyrene microspheres, carbon black, or polyethylene glycol as pore expanders. The supports are then titrated into spheres using an oil-ammonia column molding method, and finally the pore expanders are calcined off at high temperature, leaving pores. However, practice shows that when the total pore volume of the support is increased to over 1.0 mL / g and the proportion of macropores (pore diameter > 100 nm) exceeds 30%, the system encounters a bottleneck. The sharp increase in support porosity is accompanied by a precipitous decrease in macroscopic mechanical strength.

[0004] Furthermore, the single-particle crushing strength of this conventionally prepared high-porosity, ultra-large-pore support is typically less than 40 N / particle. In industrial fixed-bed reactors with loading capacities of hundreds of tons, the bottom catalyst, under hydrostatic pressure of tens of megapascals and the scouring effect of gas-liquid fluids, will experience severe particle fragmentation and pulverization in less than 1000 hours of continuous operation. Pulverization can cause the reactor bed pressure drop to surge from the normal 0.2 MPa to over 1.5 MPa, leading to a shutdown of the unit.

[0005] The root cause of the above problems lies in the fact that existing pore-expanding agents merely act as sacrificial templates for physical site placement. After being removed by high-temperature combustion, they not only leave behind huge physical voids, but the intense exothermic oxidation also disrupts the grain boundary fusion of the surrounding alumina framework. At this point, the γ-Al₂O₃ framework walls become thinner, and the neck connections between grains are in a disordered and fragile physical stacking state, lacking the support of a nanoscale chemical bonding network, and thus unable to resist external stress concentration. Therefore, it is necessary to develop a novel process for preparing ultra-large porous spherical alumina supports to solve the problem of framework brittleness and weakness when constructing ultra-large porous systems. Summary of the Invention

[0006] This invention provides a method for preparing an ultra-large porous hydrogenated spherical alumina support to improve the mechanical properties of the ultra-large porous hydrogenated spherical alumina support.

[0007] To achieve the above objectives, the preparation method of the ultra-large porous hydrogenated spherical alumina support of the present invention adopts the following technical solution:

[0008] A method for preparing an ultra-large porous hydrogenated spherical alumina support includes the following steps:

[0009] a) Prepare a slurry by mixing nanocellulose with an aminosilane coupling agent in water;

[0010] b) Mix boehmite, inorganic strong acid and water, knead for 20-40 minutes to obtain a preliminary sol;

[0011] Then, the initial sol, the slurry obtained in step b), and the basic aluminum chloride solution are stirred for 40-50 minutes to obtain the slurry.

[0012] The obtained slurry was molded to obtain wet gel spheres;

[0013] c) Mix the wet gel balls obtained in step b) with urea solution and perform a hydrothermal reaction at 110-130℃ for 5-7 hours; wash with water; dry; then keep at 230-260℃ for 1.5-3 hours in an oxygen-containing atmosphere, then keep at 420-480℃ for 2-4 hours, and then keep at 720-780℃ for 3-6 hours to obtain the final product.

[0014] Before using nanocellulose, the technical solution of this invention pre-modifies its surface with an aminosilane coupling agent through surface chemical grafting to form a "cellulose core-silica shell" structure. During the sizing stage, basic aluminum chloride (ACH), which has a high degree of polymerization, is added. A coupling reaction occurs in the molding system: the amino groups on the shell of the aminosilane coupling agent act as a local acid-base buffer, promoting the directional hydrolysis and condensation of ACH on the fiber surface; simultaneously, the silanol groups generated from the shell hydrolysis form strong covalent bonds with the pseudoboehmite and the aluminum hydroxyl groups of ACH. The hydrothermal reaction allows the pseudoboehmite grains to grow further along the cellulose network in a directional manner, consolidating the three-dimensional framework.

[0015] The sintering process was divided into three stages:

[0016] During the low-temperature stage (anchoring), the silanol and aluminol groups on the pore walls undergo a dehydration condensation reaction, forming a tough cross-linked network. The reaction mechanism can be represented as follows:

[0017] Si-OH + HO-Al → Si-O-Al + H2O

[0018] Intermediate temperature stage (pore formation): The internal cellulose undergoes relatively complete thermal oxidative decomposition, releasing carbon dioxide and water vapor. These gases form a large number of continuous, ultra-large pores in situ within the system. The reaction mechanism can be represented as follows:

[0019] C6H 10 O5 + 6O2 → 6CO2 + 5H2O

[0020] High-temperature stage (strengthening): The silicon-rich aluminum interface on the surface of the pore wall undergoes a solid-phase transformation, which can generate a microcrystalline hardened layer. These microcrystalline hardened layers can significantly improve the strength of the pore wall.

[0021] Preferably, in step a), the mass ratio of nanocellulose to aminosilane coupling agent is 280-300:1.

[0022] Preferably, the aspect ratio of the nanocellulose in step a) is not less than 1000. Preferably, the nanocellulose in step a) is a nanocellulose hydrogel.

[0023] Through the above scheme, nanocellulose naturally possesses an ultra-long, three-dimensional interpenetrating network topology with a diameter of 30-50 nm and a length of up to the micrometer level. Using it as a template, three-dimensional interconnected ultra-large channels can be constructed within the carrier, which not only greatly reduces mass transfer resistance, but its interwoven network can also effectively disperse external stress.

[0024] Preferably, the aminosilane coupling agent in step 1) is 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, or N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

[0025] Preferably, in step 1), mixing the nanocellulose and the aminosilane coupling agent in water involves first homogenizing the nanocellulose in water, then adding the aminosilane coupling agent dropwise at 60-65°C, and stirring for 3-5 hours. The homogenization speed is 4000-10000 rpm, the homogenization time is 20-40 minutes, and the dropwise addition rate is 0.5-2 mL / min. After stirring for 3-5 hours, the mixture is allowed to stand for 10-15 hours.

[0026] Through the above steps, silane coupling agents are covalently grafted onto the surface of cellulose nanofibers to form an active shell with amino and silanol groups, thereby enhancing subsequent reactions.

[0027] Preferably, in step b), the inorganic strong acid is either nitric acid or hydrochloric acid. The nitric acid is concentrated nitric acid, with a mass fraction of 65%-68%. The hydrochloric acid is concentrated hydrochloric acid, with a mass fraction of 36-38%.

[0028] Preferably, in step b), the mass ratio of pseudoboehmite to inorganic strong acid is 1000:20-40.

[0029] The role of inorganic strong acids is similar to chemical colloidation. The abundant hydrogen ions in these acids interact with boehmite, giving the particle surface a positive charge. Due to the repulsion of like charges, the clustered micron-sized powder rapidly disintegrates, breaking down into primary colloidal particles ranging from a few nanometers to tens of nanometers in size. These positively charged nanoparticles are uniformly dispersed in water, with water molecules bound around them to form a hydration layer. However, the amount of inorganic strong acid added needs strict control. Adding too much will cause the slurry to disperse like loose sand in the oil phase after being dripped, preventing it from forming perfect spheres due to surface tension.

[0030] Preferably, in step b), the mass ratio of boehmite to water is 100:80-140.

[0031] Preferably, in step b), the mass ratio of pseudoboehmite to inorganic strong acid is 100:20-40.

[0032] Preferably, the dry basis mass content of boehmite in step b) is 72.5%. The specific surface area of ​​boehmite is 320.0 m². 2 / g.

[0033] Preferably, in step b), the stirring speed when mixing boehmite with inorganic strong acid and water is 80-200 pm.

[0034] Preferably, the mass ratio of boehmite in step b) to nanocellulose in step 1) is 100:80-180.

[0035] Preferably, in step b), the mass ratio of boehmite to basic aluminum chloride solution is 100:220-250, and the mass fraction of basic aluminum chloride solution is 20%-25%.

[0036] Preferably, in step b), the stirring speed when stirring the initial sol with the slurry and basic aluminum chloride solution prepared in step 1) is 280-350 rpm.

[0037] Preferably, the viscosity of the slurry in step b) is 700-900 mPa·s.

[0038] Experiments have shown that setting this viscosity range can ensure the best possible molding results in subsequent steps, avoiding inconsistent shapes and sizes.

[0039] Preferably, in step b), the molding process employs an oil-ammonia column molding method (also known as liquid column molding or water column molding). The upper liquid in the oil-ammonia column molding is liquid paraffin, and the lower liquid is ammonia. The mass fraction of the ammonia is 10%-12%. The height ratio of the upper liquid to the lower liquid is 1-1.2:1. Preferably, the column height of the oil-ammonia column molding can be determined according to the scale of the experiment; however, to ensure the uniformity and shape of the molding, the column height should not be too small, generally 1-2 m is preferable.

[0040] Through the above steps, the slurry droplets shrink into perfect spheres in the oil phase due to surface tension. After entering the ammonia phase, they undergo rapid acid-base neutralization and gelation, and finally deposit at the bottom to form wet gel spheres, resulting in perfectly shaped particles with a more uniform texture.

[0041] Preferably, in step c), the volume ratio of the wet gel spheres to the urea solution is 1:2-3. The concentration of the urea solution is 1.5-3 g / L.

[0042] Preferably, the drying temperature in step c) is 90-100℃.

[0043] Preferably, the oxygen-containing atmosphere in step c) is an air atmosphere.

[0044] Preferably, in step c), the heating rate to 230-260℃ is 1-2℃ / min. The heating rate to 420-480℃ is 3-4℃ / min. The heating rate to 420-480℃ is 5-7℃ / min.

[0045] The above-described technical solution of the present invention has at least the following beneficial effects:

[0046] The preparation method of the present invention is based on the synergistic crosslinking of a core-shell reactive template and an inorganic polymeric aluminum binder, and constructs micro-reinforced pore walls in situ through segmented cascade calcination. By introducing a multi-component coupling reaction, a mullite-like microcrystalline hardened layer is generated in situ at the pore wall interface of the carrier, thereby improving mechanical strength while maintaining high porosity.

[0047] Nanocellulose was introduced during the construction of the microscopic three-dimensional template, and nanocellulose can form an interwoven network in the fluid. Furthermore, this invention uses an aminosilane coupling agent to perform surface grafting modification on the above-mentioned cellulose to achieve surface functionalization. Simultaneously, a highly polymerized inorganic polynuclear aluminum crosslinking agent, basic aluminum chloride aqueous solution, is used not only as a binder but also as an aluminum-rich source to participate in the in-situ solid-phase reaction at the interface. Attached Figure Description

[0048] Figure 1 XRD pattern of the ultra-large porous hydrogenated spherical alumina support prepared in Example 1 of this application. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0050] Unless otherwise specified, the raw materials used in the following examples and comparative examples are generally commercially available products. Preferably, the boehmite used in the following examples has a dry basis mass content of 72.5% and a specific surface area of ​​320.0 m². 2 / g. The aspect ratio of the nanocellulose used in the following examples is 1000. The purity of the 3-aminopropyltriethoxysilane used in the following examples is 98%.

[0051] Example 1

[0052] The preparation method of the ultra-large porous hydrogenated spherical alumina support in this embodiment includes the following steps:

[0053] 1) Place 1500g of nanocellulose in a high-speed disperser, add 500mL of deionized water, and homogenize at 8000rpm for 30min;

[0054] The system was heated to 60°C, and then 5.0 g APTES was added dropwise at a rate of 1 mL / min, while stirring continuously for 4 h. The resulting slurry was then allowed to stand at room temperature for 12 h.

[0055] 2) Take 1000g of boehmite and slowly add a mixture of 1300mL of deionized water and 30.0mL of nitric acid while stirring at 150rpm. Stir and knead for 30min to form a preliminary sol. Add the slurry prepared in step 1) and 250g of 23% basic aluminum chloride aqueous solution (ACH). Then increase the speed to 300rpm and stir for 45min. Under the buffering effect of amino groups on the surface of the slurry, ACH is prevented from agglomerating and is uniformly penetrated and crosslinked between the boehmite particles to form a milky white slurry with a viscosity of 800mPa·s.

[0056] 3) Assemble a 2.0m high liquid column molding device (water column molding device), with a 1.2m high liquid paraffin phase on the upper layer (maintained at 45℃) and a 0.8m high 12% ammonia water phase on the lower layer; drip the slurry from step 2) into the molding column at a rate of 60 drops / min through a porous dropper with a 2.5mm aperture to form wet gel spheres;

[0057] 4) The wet gel balls from step 3) are transferred to a high-pressure reactor, and twice the volume of deionized water containing 2.0 g / L urea is added. The reactor is subjected to a hydrothermal reaction at 120°C and its own pressure for 6 hours. After the reaction, the mixture is washed with water until it is neutral.

[0058] 5) Dry the gel balls washed in step 4) at 90℃ for 12 hours in a drying oven, then transfer them to a tube furnace (temperature control accuracy ±1℃) and heat them in a flowing air atmosphere with a flow rate of 500 mL / min: heat to 250℃ at a heating rate of 2℃ / min and hold for 2 hours; then heat to 450℃ at a heating rate of 3℃ / min and hold for 3 hours; then heat to 750℃ at a heating rate of 5℃ / min and hold for 4 hours, and cool with the furnace to obtain the final product.

[0059] Furthermore, step 1) in Example 1 can promote the covalent grafting of the silane coupling agent onto the surface of the cellulose nanofibers, forming an active shell with amino and silanol groups. In other embodiments, if local agglomeration of the fibers is observed during the homogenization process, ultrasonic dispersion at a frequency of approximately 50 kHz can be added beforehand to ensure a uniform distribution of the network structure. In other embodiments, the viscosity in step 2) is set to 1000 mPa·s for better shaping. This viscosity range is adjusted within 600-1000 mPa·s, but in practice, it is generally not advisable to exceed 700-900 mPa·s. In other embodiments, the aminosilane coupling agent can be selected from 3-aminopropyltrimethoxysilane or N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, with 3-aminopropyltriethoxysilane (APTES) being preferred for its coupling effect.

[0060] Without nitric acid, the pseudoboehmite powder particles are tightly bound together by hydrogen bonds and van der Waals forces, making them prone to precipitation and stratification, which is detrimental to good dispersion in water. In other embodiments, the mass ratio of pseudoboehmite to nitric acid can be selected in the range of 100:20-40. In other embodiments, hydrochloric acid can also be added; however, nitric acid, in addition to not leaving impurities after sintering, also does not leave any corrosive components to the equipment, which is beneficial for large-scale production. Therefore, nitric acid is preferred as the inorganic strong acid.

[0061] Example 2

[0062] The preparation method of the ultra-large porous hydrogenated spherical alumina support in this embodiment includes the following steps:

[0063] 1) Place 800g of nanocellulose in a high-speed disperser, add 250mL of deionized water, and homogenize at 4500rpm for 30min;

[0064] The system was heated to 65°C, and then 5.0 g APTES was added dropwise at a rate of 0.8 mL / min, while stirring continuously for 4 h. The resulting slurry was then allowed to stand at room temperature for 12 h.

[0065] 2) Take 1000g of boehmite and slowly add a mixture of 1300mL of deionized water and 30.0mL of nitric acid while stirring at 180rpm. Stir and knead for 30min to form a preliminary sol. Add the slurry prepared in step 1) and 250g of 23% basic aluminum chloride aqueous solution (ACH). Then increase the speed to 300rpm and stir for 45min to form a milky white slurry with a viscosity of 800mPa·s.

[0066] The other steps are the same as in Example 1.

[0067] Example 3

[0068] The preparation method of the ultra-large porous hydrogenated spherical alumina support in this embodiment includes the following steps:

[0069] 1) Place 1500g of nanocellulose in a high-speed disperser, add 500mL of deionized water, and homogenize at 8000rpm for 30min;

[0070] The system was heated to 60°C, and then 5.0 g APTES was added dropwise at a rate of 1 mL / min, while stirring continuously for 4 h. The resulting slurry was then allowed to stand at room temperature for 12 h.

[0071] 2) Take 1000g of pseudoboehmite, and slowly add a mixture of 1300mL of deionized water and 30.0mL of nitric acid while stirring at 150rpm. Stir and knead for 30min to form a preliminary sol. Add the slurry prepared in step 1) and 250mL of deionized water, and then increase the speed to 300rpm and stir for 45min.

[0072] The other steps are the same as in Example 1.

[0073] Example 4

[0074] The preparation method of the ultra-large porous hydrogenated spherical alumina support in this embodiment includes the following steps:

[0075] 1) Place 1500g of nanocellulose in a high-speed disperser, add 500mL of deionized water, and homogenize at 8000rpm for 30min;

[0076] The system was heated to 60°C, and then 30.0 g APTES was added dropwise at a rate of 1 mL / min, while stirring continuously for 4 h. The resulting slurry was then allowed to stand at room temperature for 12 h.

[0077] 2) Take 1000g of boehmite and slowly add a mixture of 1200mL of deionized water and 30.0mL of nitric acid while stirring at 150rpm. Stir and knead for 30min to form a preliminary sol. Add the slurry prepared in step 1) and 250g of 23% basic aluminum chloride aqueous solution (ACH). Then increase the speed to 300rpm and stir for 45min. Under the buffering effect of amino groups on the surface of the slurry, ACH is prevented from agglomerating and is uniformly penetrated and crosslinked between the boehmite particles to form a milky white slurry with a viscosity of 800mPa·s.

[0078] 3) Assemble a 2.0m high liquid column forming device, with a 1.2m high liquid paraffin phase on the upper layer (maintained at 45℃) and a 0.8m high 12% ammonia phase on the lower layer; drip the slurry from step 2) into the forming column at a rate of 60 drops / min through a porous dropper with a 2.5mm aperture to form wet gel spheres;

[0079] 4) The wet gel balls from step 3) are transferred to a high-pressure reactor, and twice the volume of deionized water containing 8.0 g / L urea is added. The reactor is subjected to a hydrothermal reaction at 120°C and its own pressure for 6 hours. After the reaction, the mixture is washed with water until it is neutral.

[0080] The other steps are the same as in Example 1.

[0081] Example 5

[0082] The difference between this embodiment and Embodiment 1 is that step 5) is:

[0083] After washing the gel balls in step 4), dry them in a drying oven at 90°C for 12 hours. Then, transfer them to a tube furnace and heat them in a flowing air atmosphere with a flow rate of 500 mL / min: heat them to 150°C at a heating rate of 1.5°C / min and hold for 2 hours; then heat them to 450°C at a heating rate of 3°C / min and hold for 3 hours; then heat them to 750°C at a heating rate of 5°C / min and hold for 4 hours. Cool them in the furnace to obtain the final product.

[0084] The other steps are the same as in Example 1.

[0085] Example 6

[0086] The difference between this embodiment and Embodiment 1 is that step 5) is:

[0087] After washing the gel balls in step 4), dry them in a drying oven at 90°C for 12 hours. Then, transfer them to a tube furnace and heat them in a flowing air atmosphere with a flow rate of 500 mL / min: heat to 250°C at a heating rate of 2°C / min and hold for 2 hours; then heat to 450°C at a heating rate of 3°C / min and hold for 3 hours; then heat to 900°C at a heating rate of 5°C / min and hold for 4 hours. Cool them in the furnace to obtain the final product.

[0088] The other steps are the same as in Example 1.

[0089] Comparative Example 1

[0090] The difference between this comparative example and Example 1 is that step 1) is:

[0091] 1) Place 1500g of nanocellulose in a high-speed disperser, add 500mL of deionized water, and homogenize at 8000rpm for 30min; heat the system to 60℃ and stir continuously for 4h; let the slurry obtained after stirring stand at room temperature for 12h.

[0092] The other steps are the same as in Example 1.

[0093] Comparative Example 2

[0094] The difference between this comparative example and Example 1 is that step 5) is:

[0095] After washing the gel balls in step 4), dry them in a drying oven at 90°C for 12 hours. Then, transfer them to a tube furnace and heat them in a flowing air atmosphere with a flow rate of 500 mL / min. Heat them to 750°C at a heating rate of 5°C / min, hold for 4 hours, and then cool them in the furnace to obtain the final product.

[0096] The other steps are the same as in Example 1.

[0097] Experimental Example

[0098] (1) Physical performance testing

[0099] The physical properties of the materials obtained in Examples 1-6 and Comparative Examples 1-2 were tested, and the test results are shown in the table below:

[0100] Table 1. Performance test results of the alumina carriers prepared in Examples 1-6 and Comparative Examples 1-2

[0101]

[0102] As shown in the table above, the alumina carrier prepared in Example 1 achieved a good balance in terms of total pore volume, macropore volume ratio, specific surface area, and single-particle side crushing strength. Example 2 reduced the amount of template, resulting in a significant increase in strength, but a sharp drop in total pore volume and macropore volume ratio, demonstrating that the amount of template is the decisive factor in the formation of ultra-large pores. Example 3 eliminated the aluminum binder; although the total pore volume remained unchanged, the strength decreased by 51%, strongly demonstrating that the aluminum binder is the structural bridge connecting coarse alumina particles and fine cellulose templates. Example 4, by enhancing the alkaline environment and increasing the amount of coupling agent, obtained the highest total pore volume, macropore ratio, and excellent strength, indicating that promoting appropriate alumina grain growth and simultaneously enhancing interfacial crosslinking is an effective way to further improve the pore structure performance of the carrier. Example 5 reduced the insulation temperature of the low-temperature anchoring section. Although its total pore volume and macropore volume ratio were similar to those of Example 1, the strength decreased by 28%. This may be because the low-temperature anchoring was insufficient to form a solid silicon-aluminum cross-linked network. During the subsequent high-temperature calcination process, some pore wall structures tore due to the stress generated by the rapid combustion of cellulose. Example 6 increased the temperature of the high-temperature strengthening section. Although the strength increased by 10%, the total pore volume, macropore volume ratio, and specific surface area decreased significantly, indicating that high-temperature sintering led to excessive shrinkage and agglomeration of alumina grains, sacrificing the pore structure.

[0103] Comparative Example 1, which did not use a silane coupling agent, formed a pore structure similar to that of Example 1, but with extremely low strength. This directly confirms the role of the silane coupling agent in forming a reinforcing skeleton at the pore wall interface through anchoring. Comparative Example 2, which used conventional rapid calcination, showed a significant decrease in strength and a pore structure inferior to that of Example 1, indicating that the low-temperature dehydration anchoring and medium-temperature slow decarburization of the present invention are necessary steps to prevent pore wall cracking and maintain the integrity of the skeleton.

[0104] from Figure 1 In the image, broadened diffraction peaks appear around 37°, 46°, and 67°, which are characteristic diffraction peaks of γ-Al2O3. The broadened peak shape indicates that the alumina crystals of the product maintain a nanoscale and possess the high specific surface area characteristics required for a catalytic support. Weak and diffuse diffraction peaks belonging to the mullite-like microcrystalline phase appear at 26.5° and 35°, corresponding to the characteristic crystal planes of aluminum-rich aluminosilicate microcrystals. The absence of sharp diffraction peaks of the free SiO2 crystal phase indicates that this application uses a synergistic process of modification with aminosilane coupling agent, basic aluminum chloride cementation to assist in in-situ interfacial bonding, and coupled with three-stage graded calcination to generate a low-crystallinity mullite-like microcrystalline hardened layer in situ at the alumina pore wall interface.

[0105] (2) Performance testing of metal patina

[0106] Under conditions of 380℃, 15.0MPa, and an H2 / oil volume ratio of 600, a solution containing 120μg·g was used. -¹(Ni+V) vacuum residue was used as feed gas and tested in continuous operation. The test results are shown in the table below.

[0107] Table 2. Test data of gold compatibilization performance in Examples 1 and 2

[0108]

[0109] Combining the data in Tables 1 and 2, it can be seen that the sample prepared in Example 1, thanks to its ultra-large pore structure and high-strength mass transfer channels, achieved deep penetration and high capacity loading of metal contaminants, while maintaining stable bed resistance. In Example 2, the significantly reduced pore volume and macropore ratio led to increased metal diffusion resistance, insufficient penetration depth, and a decrease in effective metal capacity.

[0110] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an ultra-large porous hydrogenated spherical alumina support, characterized in that, The steps include the following: a) Prepare a slurry by mixing nanocellulose with an aminosilane coupling agent in water; b) Mix boehmite, inorganic strong acid and water, knead for 20-40 minutes to obtain a preliminary sol; the mass ratio of boehmite to nanocellulose is 100:

150. Then, the initial sol, the slurry obtained in step a), and the basic aluminum chloride solution are stirred for 40-50 minutes to obtain the slurry. The obtained slurry was molded to obtain wet gel spheres; c) Mix the wet gel balls obtained in step b) with urea solution and perform a hydrothermal reaction at 110-130℃ for 5-7 hours; wash with water; dry; then keep at 230-260℃ for 1.5-3 hours in an oxygen-containing atmosphere, then keep at 420-480℃ for 2-4 hours, and then keep at 720-780℃ for 3-6 hours to obtain the final product.

2. The method for preparing the ultra-large porous hydrogenated spherical alumina support according to claim 1, characterized in that, In step a), the mass ratio of nanocellulose to aminosilane coupling agent is 280-300:

1.

3. The method for preparing the ultra-large porous hydrogenated spherical alumina support according to claim 1, characterized in that, In step a), the aminosilane coupling agent is 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, or N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

4. The method for preparing the ultra-large porous hydrogenated spherical alumina support according to claim 1, characterized in that, In step b), the inorganic strong acid is either nitric acid or hydrochloric acid.

5. The method for preparing the ultra-large porous hydrogenated spherical alumina support according to claim 1, characterized in that, In step b), the mass ratio of pseudoboehmite to inorganic strong acid is 1000:20-40.

6. The method for preparing the ultra-large porous hydrogenated spherical alumina support according to claim 5, characterized in that, In step b), the mass ratio of pseudoboehmite to water is 100:80-140.

7. The method for preparing the ultra-large porous hydrogenated spherical alumina support according to claim 1, characterized in that, In step b), the mass ratio of boehmite to basic aluminum chloride solution is 100:220-250, and the mass fraction of basic aluminum chloride solution is 20-25%.

8. The method for preparing the ultra-large porous hydrogenated spherical alumina support according to any one of claims 1-7, characterized in that, The viscosity of the slurry in step b) is 700-900 mPa·s.

9. The method for preparing the ultra-large porous hydrogenated spherical alumina support according to any one of claims 1-7, characterized in that, The molding process described in step b) uses an oil-ammonia column molding method.

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