Catalytic slurry oil hydrotreating method

Abstract

The invention discloses a catalytic cracking oil slurry hydrotreating method. A fixed bed hydrogenation process is adopted, and the method comprises the following steps: in the presence of hydrogen, catalytic cracking slurry oil is sequentially contacted with a hydrogenation protective agent, a hydrogenation transition catalyst and a hydrodesulfurization catalyst for hydrogenation reaction to obtain hydrogenated oil; wherein the hydrogenation protective agent comprises an alumina carrier with the most probable pore size of 40-100 nm, molybdenum oxide and cobalt oxide; the hydrogenation transition catalyst comprises an alumina carrier containing an auxiliary agent, MoO3 and CoO, the carrier has bimodal pore size distribution, the smaller pore size is intensively distributed at 10-40nm, and the larger pore size is intensively distributed at 150-400nm. The method provided by the invention can eliminate the diffusion resistance of macromolecules on the surface of the catalyst during adsorption and reaction in the catalytic cracking slurry oil hydrogenation process, can accommodate more deposits such as carbon deposits, prolongs the operation period of the device, is beneficial to the proceeding of reactions such as hydrodesulfurization, improves the content of tricyclic and tetracyclic aromatic hydrocarbons in the hydrogenated oil, and improves the yield of the catalytic cracking slurry oil. The raw material is a high-quality raw material for producing needle coke.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogenation, and in particular relates to a catalytic oil slurry hydrogenation treatment method. Background Art

[0002] As oil resources continue to degrade and become heavier, market demand for diversified and lighter petrochemical products is increasing. Processing low-quality, heavy crude oil has become a critical issue for refineries worldwide. Catalytic cracking technology is one of the three main processes for deep processing of heavy oil and a key technology for lightweighting feedstocks. It is also highly adaptable to feedstocks. Currently, some FCC units can directly process atmospheric residue or blend it with vacuum residue, leading to problems such as a poor distribution of FCC products. To increase unit throughput, reduce energy consumption, and increase the production of lighter products, slurry oil disposal is a promising solution. This, in turn, generates a large amount of FCC slurry oil as a byproduct. As a low-value-added product of the FCC process, FCC slurry oil exhibits high density, high carbon residue, high viscosity, and a high aromatic content. It also contains residual catalyst particles and coke, making it challenging to process and utilize. Therefore, how to process and utilize FCC slurry oil has become a critical issue that refineries urgently need to address.

[0003] Catalytic cracking oil, rich in aromatics, is an ideal raw material for producing high-end carbon-based materials such as needle coke. Needle coke boasts high crystallinity, high strength, high graphitization, low thermal expansion, and low ablation, making it primarily used in ultra-high-power graphite electrodes and lithium-ion battery anode materials. As a raw material for needle coke production, catalytic cracking oil is typically required to have low sulfur, low nitrogen, and low ash content, and high aromatic content, particularly high levels of tri- and tetra-ring aromatics. FCC oil has high density, high carbon residue, high viscosity, high aromatic content, and contains residual catalyst particles and coke, making it difficult to utilize. Currently, high-quality, low-sulfur oil resources are extremely scarce, while lower-quality oils have high sulfur contents (1.0 wt% to 2.0 wt%). Needle coke products have strict sulfur content requirements (≤ 0.5 wt%), and processing with conventional residue oil hydrotreating catalysts results in excessive aromatic losses. At present, there are few studies on hydrogenation catalysts dedicated to catalytic cracking slurry oil. Therefore, it is of great significance to develop a catalyst suitable for hydrogenation of catalytic cracking slurry oil.

[0004] CN103013567A discloses a method for producing needle coke feedstock from catalytic cracking slurry. The method comprises a protection zone and a hydrogenation reaction zone. The protection zone is filled with an adsorbent capable of absorbing catalytic cracking catalyst powder, while the hydrogenation reaction zone is sequentially filled with a hydrogenation protective agent, a hydrogenation demetallization agent, and a hydrogenation desulfurization agent according to the flow direction of the reactants. The catalytic cracking slurry first enters the protection zone to absorb most of the catalytic cracking catalyst powder, then mixes with hydrogen and enters a heating furnace. After heating, it enters the hydrogenation reaction zone for hydrogenation. Among them, the hydrogenation protective agent is a Raschig ring, which is a conventional residue oil hydrogenation protective agent. The hydrodemetallization agent contains an alumina carrier and molybdenum and / or tungsten, as well as nickel and / or cobalt loaded on the carrier. The pore distribution of the carrier is that the pore volume with a pore diameter of 100-200 angstroms (10-20nm) accounts for 70%-98% of the total pore volume; the hydrodesulfurization agent contains a carrier and molybdenum and / or tungsten, as well as nickel and / or cobalt loaded on the carrier. The carrier is alumina and optional silica. The pore distribution of the carrier is that the pore volume with a diameter of 60-100 angstroms (6-10nm) accounts for 75%-98% of the total pore volume. The above-mentioned hydrodemetallization agents and hydrodesulfurization agents are both conventional residue oil hydrogenation catalysts. Although they can be used for catalytic cracking oil slurry hydrogenation, the metal content and metal deposits of the catalytic cracking oil slurry are relatively low, the pore size of the carrier is relatively small, and the macropore volume is relatively small. During the hydrogenation reaction, the adsorption and reaction of macromolecules such as colloids and asphaltenes in the catalytic cracking oil slurry are affected by diffusion resistance. At the same time, the continuous deposition of carbon deposits during the hydrogenation process can easily cause pore blockage, and the carbon deposits are deposited on the downstream desulfurization catalyst, ultimately leading to plant shutdown.

[0005] Since catalytic cracking slurry oil feedstock is different from conventional residual oil feedstock, conventional residual oil hydrogenation catalysts in the prior art still have the above-mentioned problems for catalytic cracking slurry oil feedstock. Therefore, it is urgent to develop a process method suitable for catalytic cracking slurry oil hydrogenation. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention provides a method for hydrotreating catalytic cracking slurry oil. This method eliminates the adsorption of macromolecules on the catalyst surface and the diffusion resistance during the reaction during the catalytic cracking slurry oil hydrogenation process, increasing the capacity to accommodate more carbon deposits and other sediments, extending the operating cycle of the device. It also facilitates reactions such as hydrodesulfurization and increases the content of tri- and tetra-ring aromatics in the hydrogenated oil, making it a high-quality raw material for producing needle coke.

[0007] The desolidified catalytic cracking oil slurry contains relatively few metallic impurities and relatively high levels of colloids and asphaltenes (4.0% to 15.0%). Asphaltene molecules are primarily composed of 5 to 7 flaky, fused aromatic rings with sizes ranging from 12 to 16 angstroms (1.2 to 1.6 nm), and the asphaltene molecules are prone to agglomeration. Therefore, conventional residual oil hydrogenation protectants and hydrodemetallization catalysts are not very suitable for hydrogenating catalytic cracking oil slurry. The inventors have discovered that developing a hydrogenation protectant with a suitable large pore size and large pore size distribution, and a hydrogenation transition agent with a suitable bimodal pore size distribution, and using these two in a graded manner, not only facilitates the diffusion of macromolecules and accommodates more carbon deposits, but also facilitates the hydrogenation reaction of small sulfur-containing compounds such as mercaptans and sulfides, thereby achieving the initial removal of sulfur impurities from the catalytic cracking oil slurry. This plays a key role in ensuring that the performance of downstream catalysts is not affected by impurities such as carbon deposits, thereby ensuring the long-term operation of the device.

[0008] The present invention provides a catalytic cracking oil slurry hydroprocessing method, which adopts a fixed bed hydrogenation process, comprising: in the presence of hydrogen, the catalytic cracking oil slurry feedstock is sequentially contacted with a hydrogenation protective agent, a hydrogenation transition catalyst and a hydrodesulfurization catalyst to carry out a hydrogenation reaction to obtain hydrogenated oil;

[0009] The hydrogenation protective agent comprises a carrier and a hydrogenation active metal, wherein an alumina carrier is used, the hydrogenation active metal comprises molybdenum oxide and cobalt oxide, and the properties of the alumina carrier are as follows: the most probable pore diameter is 40 to 100 nm, preferably 50 to 70 nm, and the pore volume occupied by the pores from (most probable pore diameter - 30) nm to (most probable pore diameter + 30) nm accounts for more than 75% of the total pore volume, preferably 75% to 90%;

[0010] The hydrogenation transition catalyst comprises an alumina carrier containing a promoter and MoO3 and CoO. The carrier has a bimodal pore size distribution, with smaller pore sizes concentrated in the range of 10 to 40 nm, and the pore volume of pores with a pore size of 10 to 40 nm accounting for 20% to 40% of the total pore volume; and larger pore sizes concentrated in the range of 150 to 400 nm, and the pore volume of pores with a pore size of 150 to 400 nm accounting for 30% to 50% of the total pore volume.

[0011] In the present invention, based on the mass of the hydrogenation protective agent, the mass content of MoO3 is 2.0% to 7.0%, and the mass content of CoO is 0.3% to 1.7%.

[0012] In the present invention, based on the mass of the hydrogenation protective agent, the mass content of the alumina carrier is 91.3% to 97.7%.

[0013] In the present invention, the pore volume of the alumina support in the hydrogenation protective agent is 1.00 to 1.40 cm 3 / g, preferably 1.10 to 1.30 cm 3 / g.

[0014] In the present invention, the specific surface area of ​​the alumina carrier in the hydrogenation protective agent is 120 to 180 m 2 / g, preferably 130 to 170 m 2 / g.

[0015] In the present invention, the shape of the hydrogenation protective agent is preferably a four-leaf wheel or a four-leaf clover.

[0016] The present invention also provides a method for preparing the above-mentioned hydrogenation protective agent, comprising the following steps:

[0017] a) mixing a first aluminum source, a second aluminum source, and a third aluminum source with water to obtain a slurry, and then grinding the slurry;

[0018] b) adding clean water to the slurry obtained in step a) and stirring;

[0019] c) adding a modifier, a pH regulator, and an optional dispersant to the material obtained in step b) to obtain a mixed slurry, and then subjecting the mixed slurry to a hydrothermal treatment;

[0020] d) drying the material obtained in step c) to obtain alumina dry glue;

[0021] e) mixing the alumina dry glue obtained in step d) with a binder, shaping, drying, and calcining to obtain a carrier;

[0022] f) impregnating the carrier obtained in step e) with an impregnation solution containing molybdenum and cobalt, and drying and calcining to obtain the hydrogenation protective agent.

[0023] In the method of the present invention, in step a), the first aluminum source is alumina trihydrate.

[0024] In the method of the present invention, in step a), the second aluminum source is alumina gel having a water content of 35% by mass or less. The alumina gel can be a dehydrated alumina hydrate, and can be completely dehydrated alumina or partially dehydrated alumina, such as monohydrated alumina.

[0025] In the method of the present invention, in step a), the third aluminum source is an aluminum-containing salt compound, which can be an acidic aluminum salt, or a basic aluminate and / or metaaluminate. The third aluminum source can be selected from at least one of aluminum nitrate, aluminum chloride, aluminum sulfate, sodium metaaluminate, and the like.

[0026] In the method of the present invention, in step a), the mass ratio of the first aluminum source, the second aluminum source and the third aluminum source is 30-66:33-60:1-10.

[0027] In the method of the present invention, in step a), the amount of water added is 100% to 150% of the total mass of the first aluminum source, the second aluminum source and the third aluminum source.

[0028] In the method of the present invention, in step a), the slurry is ground until the size of the particles in the slurry is 4 to 20 μm, measured by the median particle size D50.

[0029] In the method of the present invention, in step b), the slurry obtained in step a) is added with clean water (preferably deionized water) and stirred so that the total mass content of the first aluminum source, the second aluminum source and the third aluminum source in the slurry is 10% to 20%.

[0030] In the method of the present invention, in step c), the pH regulator can be an alkaline substance (such as at least one of sodium hydroxide, ammonia water, sodium bicarbonate, ammonium carbonate, etc.) or an acidic substance (such as at least one of acetic acid, citric acid, nitric acid, etc.). The added pH regulator is adjusted according to the properties of the slurry, and the pH value of the mixed slurry in step c) is controlled to be 8.5 to 12.0.

[0031] In the method of the present invention, in step c), the dispersant is selected from at least one hydrophilic dispersant. The dispersant can be a nonionic surfactant having an HLB value (Hydrophile-Lipophile Balance Number) of 10 to 20. The amount of the dispersant added is less than 10% of the mass of the material obtained in step b), preferably 0.01% to 10%. The nonionic surfactant dispersant is preferably at least one of Tween-80, lauryl alcohol polyoxyethylene ether, and methyl glucose polyoxyethylene ether. The modifier is preferably at least one of sodium hexametaphosphate, sodium tripolyphosphate, disodium ethylenediaminetetraacetic acid, sodium gluconate, sodium tartrate, etc. The amount of the modifier added is 0.01% to 6% of the mass of the material obtained in step b), for example but not limited to: 0.1%, 0.2%, 0.5%, 0.6%, 0.8%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, etc.

[0032] In the method of the present invention, in step c), the conditions of the hydrothermal treatment are as follows: temperature is 220-280° C., and time is 5-12 hours.

[0033] In the method of the present invention, in step d), the material obtained in step c) may be filtered and washed before drying. Conventional filtering and washing methods may be employed. The drying conditions are as follows: a drying temperature of 100 to 180° C. and a drying time of 4 to 10 hours.

[0034] In the method of the present invention, in step e), the binder is selected from at least one of an inorganic acid, an organic acid, cellulose, and a resin. The inorganic acid may be nitric acid, and the organic acid may be selected from at least one of acetic acid, citric acid, and tartaric acid. The cellulose may be at least one of hydroxypropyl cellulose and methyl cellulose, and the resin may be at least one of phenolic resin and ethylene-vinyl acetate resin. The amount of the binder added is 0.1% to 10% of the mass of the dry alumina gel.

[0035] In the method of the present invention, in step e), a molding aid, such as an extrusion aid, may be added depending on the molding conditions. The extrusion aid is selected from sesbania powder and the amount of the extrusion aid added is 0.5% to 6.0% of the mass of the alumina dry glue obtained in step d).

[0036] In the method of the present invention, step e) does not require the addition of pore-forming raw materials, such as pore-enlarging agents. These raw materials, such as carbon black and starch, are added during the carrier preparation process. During the molding process, the pore-enlarging agent molecules are encapsulated by the alumina powder particles. After high-temperature calcination, the pore-enlarging agent molecules are oxidized or undergo other chemical reactions to generate gases that escape, leaving behind the spaces previously occupied, thereby forming large pores.

[0037] In the method of the present invention, in step e), the formed shape can be a four-leaf wheel or a four-leaf clover shape.

[0038] In the method of the present invention, in step e), the drying conditions after forming are as follows: a drying temperature of 100-180°C and a drying time of 4-12 hours; and the calcination conditions after forming are as follows: a calcination temperature of 500-800°C and a calcination time of 3-12 hours. The calcination atmosphere can be an oxygen-containing gas, such as air.

[0039] In the method of the present invention, in step f), the impregnation solution containing molybdenum and cobalt has a cobalt content of 0.2 to 1.6 g / 100 mL (calculated as cobalt oxide), and a molybdenum content of 1.6 to 6.3 g / 100 mL (calculated as molybdenum oxide). The molybdenum source may be at least one of ammonium molybdate and molybdenum trioxide. The cobalt source may be at least one of cobalt nitrate and basic cobalt carbonate.

[0040] In the method of the present invention, in step f), the impregnation is preferably carried out by saturation impregnation.

[0041] In the method of the present invention, in step f), the drying conditions after impregnation are as follows: a drying temperature of 100-180°C for a drying time of 4-12 hours; and the calcination conditions are as follows: a calcination temperature of 450-600°C for a calcination time of 3-6 hours. The calcination atmosphere is an oxygen-containing atmosphere, such as air.

[0042] In the present invention, the hydrogenation transition catalyst comprises an alumina carrier containing a promoter and MoO3 and CoO. The carrier has a bimodal pore size distribution, with the smaller pore size concentrated in the range of 10 to 40 nm, and the pore volume of the pores with a pore size of 10 to 40 nm accounting for 20% to 40% of the total pore volume; the larger pore size concentrated in the range of 150 to 400 nm, and the pore volume of the pores with a pore size of 150 to 400 nm accounting for 30% to 50% of the total pore volume.

[0043] In the present invention, the pore volume of the carrier in the hydrogenation transition catalyst is 0.95 to 1.35 cm 3 / g, preferably 1.00 to 1.25 cm 3 / g.

[0044] In the present invention, the specific surface area of ​​the carrier in the hydrogenation transition catalyst is 110 to 175 m 2 / g, preferably 130 to 170 m 2 / g.

[0045] In the present invention, based on the mass of the hydrogenation transition catalyst, the content of MoO3 is 4.0% to 10.0%, and the content of CoO is 0.8% to 2.5%.

[0046] In the present invention, the shape of the hydrogenation transition catalyst is preferably a four-leaf clover shape.

[0047] In the present invention, in the hydrogenation transition catalyst, in the alumina carrier containing the additive, the additive is preferably one or more of fluorine, phosphorus, silicon or boron; the content of the additive as an element accounts for 0.2% to 10% of the total mass of the alumina in the carrier, preferably 1% to 6%.

[0048] In the present invention, the preparation method of the above-mentioned hydrogenation transition catalyst comprises the following steps:

[0049] A) mixing a first aluminum source, a second aluminum source, and a third aluminum source with water to obtain a slurry, and then grinding the slurry;

[0050] B) adding clean water to the slurry obtained in step A) and stirring;

[0051] C) adding a pH regulator, a modifier, an auxiliary agent precursor, and an optional dispersant to the material obtained in step B) to obtain a mixed slurry, and then subjecting the mixed slurry to a hydrothermal treatment;

[0052] D) drying the material obtained in step C) to obtain alumina dry gel;

[0053] E) mixing the alumina dry gel obtained in step D) with a binder, shaping, drying, and calcining to obtain a carrier;

[0054] F) impregnating the support obtained in step E) with an impregnation solution containing molybdenum and cobalt, and drying and calcining to obtain the hydrogenation transition catalyst.

[0055] In the method of the present invention, in step A), the first aluminum source is alumina trihydrate.

[0056] In the method of the present invention, in step A), the second aluminum source is alumina gel having a water content of 35% by mass or less. The alumina gel can be a dehydrated alumina hydrate, and can be completely dehydrated alumina or partially dehydrated alumina, such as monohydrated alumina.

[0057] In the method of the present invention, in step A), the third aluminum source is an aluminum-containing salt compound, which can be an acidic aluminum salt, or a basic aluminate and / or metaaluminate. The third aluminum source can be selected from at least one of aluminum nitrate, aluminum chloride, aluminum sulfate, sodium metaaluminate, and the like.

[0058] In the method of the present invention, in step A), the mass ratio of the first aluminum source, the second aluminum source and the third aluminum source is 30-66:33-60:1-10.

[0059] In the method of the present invention, in step A), the amount of water added is 100% to 150% of the total mass of the first aluminum source, the second aluminum source and the third aluminum source.

[0060] In the method of the present invention, in step A), the slurry is ground until the size of the particles in the slurry is 4 to 20 μm, measured by the median particle size D50.

[0061] In the method of the present invention, in step B), the slurry obtained in step A) is added with clean water (preferably deionized water) and stirred so that the total mass content of the first aluminum source, the second aluminum source and the third aluminum source in the slurry is 10% to 20%.

[0062] In the method of the present invention, in step C), the pH regulator can be an alkaline substance (such as at least one of sodium hydroxide, ammonia water, sodium bicarbonate, ammonium carbonate, etc.) or an acidic substance (such as at least one of acetic acid, citric acid, nitric acid, etc.). The added pH regulator is adjusted according to the properties of the slurry, and the pH value of the mixed slurry in step C) is controlled to be in the range of 9.0 to 12.5.

[0063] In the method of the present invention, in step c), the dispersant is selected from at least one hydrophilic dispersant. The dispersant can be a non-ionic surfactant having an HLB value (Hydrophile-Lipophile Balance Number) of 10 to 20. The amount of the dispersant added is less than 10% of the mass of the material obtained in step b), preferably 0.01% to 10%. The non-ionic surfactant dispersant is preferably at least one of Tween-80, lauryl alcohol polyoxyethylene ether, and methyl glucose polyoxyethylene ether. The modifier is preferably at least one of sodium hexametaphosphate, sodium tripolyphosphate, disodium ethylenediaminetetraacetic acid, sodium gluconate, sodium tartrate, etc. The amount of the modifier added is 0.01% to 10% of the mass of the material obtained in step B), preferably 0.01% to 6%, and examples include but are not limited to: 0.1%, 0.2%, 0.5%, 0.6%, 0.8%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, etc.

[0064] In the method of the present invention, in step C), the auxiliary agent is preferably one or more of fluorine, phosphorus, silicon or boron, preferably silicon. Based on the total mass of the first aluminum source, the second aluminum source and the third aluminum source, the amount of the auxiliary agent (calculated as oxide) added accounts for 0.2% to 10% of the total mass of the alumina, preferably 1% to 6%. The auxiliary fluorine precursor can be at least one of hydrofluoric acid, ammonium fluoride, boron trifluoride, and sodium fluorosilicate. The auxiliary phosphorus precursor can be at least one of phosphoric acid, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate. The auxiliary silicon precursor can be at least one of silica sol, water glass, and fluorosilicic acid. The auxiliary boron precursor can be at least one of boric acid, sodium borate, ammonium borate, and ammonium metaborate.

[0065] In the method of the present invention, in step C), the conditions of the hydrothermal treatment are as follows: temperature is 200-260° C., and the hydrothermal time is 4-10 hours.

[0066] In the method of the present invention, in step D), before drying, the material obtained in step c) can be filtered, washed, etc. Conventional filtering and washing methods can be used for the filtration and washing.

[0067] In the method of the present invention, in step D), the drying conditions are: drying temperature is 100-180° C., and drying time is 4-12 hours.

[0068] In the method of the present invention, in step E), the binder is selected from at least one of an inorganic acid, an organic acid, cellulose, and a resin. The inorganic acid may be nitric acid, and the organic acid may be selected from at least one of acetic acid, citric acid, and tartaric acid. The cellulose may be at least one of hydroxypropyl cellulose and methyl cellulose, and the resin may be at least one of phenolic resin and ethylene-vinyl acetate resin. The amount of the binder added is 0.1% to 10% of the mass of the dry alumina gel.

[0069] In the method of the present invention, in step E), a molding aid, such as an extrusion aid, may be added depending on the molding conditions. The extrusion aid is selected from sesbania powder and the amount of the extrusion aid added is 0.5% to 6.0% of the mass of the alumina dry glue obtained in step D).

[0070] In the method of the present invention, step E) does not require the addition of pore-forming raw materials, such as pore-enlarging agents. These raw materials, such as carbon black and starch, are added during the carrier preparation process. During the molding process, the pore-enlarging agent molecules are encapsulated by the alumina powder particles. After high-temperature calcination, the pore-enlarging agent molecules are oxidized or undergo other chemical reactions to generate gases that escape, leaving behind the spaces previously occupied, thereby forming large pores.

[0071] In the method of the present invention, in step E), the formed shape may be a four-leaf clover shape.

[0072] In the method of the present invention, in step E), the drying temperature after forming is 100-180° C., and the drying time is 4-12 hours; the calcination temperature after forming is 500-800° C., and the calcination time is 3-12 hours.

[0073] In the method of the present invention, in step F), the impregnation solution containing molybdenum and cobalt has a cobalt content of 0.7 to 2.4 g / 100 mL (calculated as cobalt oxide), and a molybdenum content of 3.8 to 9.6 g / 100 mL (calculated as molybdenum oxide). The molybdenum source may be at least one of ammonium molybdate and molybdenum trioxide. The cobalt source may be at least one of cobalt nitrate and basic cobalt carbonate.

[0074] In the method of the present invention, in step F), the impregnation can be saturated impregnation or supersaturated impregnation, and saturated impregnation is preferably used.

[0075] In the method of the present invention, in step F), the drying conditions after impregnation are as follows: a drying temperature of 100-180°C for a drying time of 4-12 hours; and the calcination conditions are as follows: a calcination temperature of 450-600°C for a calcination time of 3-6 hours. The calcination atmosphere is an oxygen-containing atmosphere, such as air.

[0076] In the method of the present invention, the hydrodesulfurization catalyst can be a conventional residual oil hydrodesulfurization catalyst. The hydrodesulfurization catalyst generally comprises an alumina carrier and a hydrogenation-active metal component. The hydrogenation-active metal component is preferably a Group VIB and Group VIII metal. The Group VIB metal is preferably W and / or Mo. The Group VIII metal is preferably Ni and / or Co. The hydrodesulfurization catalyst has a Group VIB oxide content of 6% to 16% and a Group VIII metal oxide content of 1.5% to 6.0%, based on the weight of the catalyst. The hydrodesulfurization catalyst can be purchased commercially, such as the FZC series catalyst developed and produced by Sinopec Fushun Petrochemical Research Institute.

[0077] In the method of the present invention, the percentage of the filling volume of the hydrogenation protective agent, the hydrogenation transition catalyst and the hydrodesulfurization catalyst to the total filling volume is 3%-30%, 10%-40% and 30%-87%.

[0078] In the method of the present invention, the basic grading principle of the hydrogenation protective agent, the hydrogenation transition catalyst and the hydrodesulfurization catalyst can adopt the grading principle of the residue oil hydrotreating catalyst, for example: along the logistics direction, the particle size gradually decreases, the bed porosity gradually decreases, the pore size gradually decreases, and the activity gradually increases. Grading according to this principle can bring out the optimal activity of the catalyst series.

[0079] In the method of the present invention, the hydrogenation protective agent, the hydrogenation transition catalyst and the hydrodesulfurization catalyst need to be sulfurized before use, and conventional in-situ presulfurization or ex-situ presulfurization in the art can be used.

[0080] In the method of the present invention, the catalytic cracking slurry oil raw material is one or more of full-fraction slurry oil, second-line slurry oil, and any fraction slurry oil.

[0081] In the method of the present invention, the operating conditions of the hydrotreatment are as follows: reaction temperature of 300-400°C, reaction pressure of 1.0-10.0 MPa, hydrogen-to-oil volume ratio of 200:1-1200:1, liquid hourly volume space velocity of 0.1-2.0h -1 .

[0082] In the method of the present invention, the hydrogenated oil obtained by hydrogenation treatment has a high content of three-ring and four-ring aromatic hydrocarbons and is a high-quality raw material for producing needle coke.

[0083] Compared with the prior art, the present invention has the following beneficial effects:

[0084] 1. In existing technologies, FCC slurry and residual oil are similar, both containing colloids and asphaltenes. However, FCC slurry and residual oil have different properties. FCC slurry contains less metals, and catalyst deactivation is primarily caused by carbon deposition. FCC slurry hydrogenation units operate differently from residual oil hydrogenation units: FCC slurry hydrogenation units typically operate for two years, while residual oil hydrogenation units operate for approximately one year. For FCC slurry hydrogenation units, with varying feedstocks and operating modes, a hydrogenation protectant with as many large pores as possible can accommodate more carbon deposits, protecting downstream catalysts and extending catalyst life, thereby ensuring long-term operation. The catalytic oil slurry hydroprocessing method of the present invention uses a specific hydrogenation protective agent and a hydrogenation transition catalyst to be graded with a conventional hydrodesulfurization catalyst. This can eliminate the adsorption of large molecules on the catalyst surface during the hydrogenation of the catalytic cracking oil slurry and the diffusion resistance during the reaction, accommodate more sediments such as carbon deposits, and is conducive to the long-term operation of the device. In addition, the hydrogenation transition catalyst can carry out the hydrogenation reaction of small sulfur-containing compounds such as mercaptans and sulfides, and the initial removal of sulfur impurities in the catalytic cracking oil slurry plays a key role in ensuring that the performance of the downstream hydrodesulfurization catalyst is not affected by impurities such as carbon deposits. While improving the overall hydrodesulfurization performance, the method of the present invention can also retain the three-ring and four-ring aromatic hydrocarbons in the catalytic cracking oil slurry to a great extent, providing an ideal raw material for the preparation of high-end carbon-based materials such as needle coke.

[0085] Specific implementation method

[0086] The following examples further illustrate the technical solutions and effects of the present invention. The examples are implemented based on the technical solutions of the present invention, and provide detailed implementation methods and specific operating processes, but the scope of protection of the present invention is not limited to the following examples.

[0087] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, were purchased from conventional biochemical reagent stores.

[0088] The pore volumes and pore diameters of the alumina carrier, catalyst, conventional residue oil hydrogenation protectant, and hydrodemetallization catalyst of the present invention (including the embodiments) were measured by mercury intrusion porosimetry using a MicroActive AutoPore V 9600 instrument.

[0089] In the present invention, the pore volume and pore diameter of the alumina supports prepared in Comparative Examples 2 and 3 were tested using a low-temperature liquid nitrogen adsorption method using an ASAP2420 pore structure analyzer produced by Micromeritics, Inc., USA.

[0090] The specific surface areas of the alumina carriers and catalysts of the present invention (including the examples) and the alumina carriers and catalysts prepared in the comparative examples were measured using a low-temperature liquid nitrogen adsorption method using an ASAP2420 pore structure analyzer from Micromeritics, USA.

[0091] Example 1

[0092] Take 100 grams of alumina trihydrate, 90 grams of alumina monohydrate and 10 grams of sodium aluminate, add 300 grams of clean water, use a ball mill to grind, 450rpm, grind for 1 hour, the D50 of the particles in the slurry is 7.43μm. Add 950 grams of clean water to the ground slurry and stir, then add 6 grams of citric acid, 5 grams of sodium hexametaphosphate, and 10 grams of Tween-80. The pH value of the slurry is 9.03. The stirred slurry is transferred to an autoclave for hydrothermal treatment at a hydrothermal temperature of 260°C and a hydrothermal time of 7 hours. The material obtained after hydrothermal treatment is filtered, washed, and dried at 120°C for 5 hours to obtain alumina dry glue;

[0093] Take 100 grams of the prepared alumina gel, add 1 gram of sesbania powder, 1 gram of methylcellulose, 0.5 gram of acetic acid, and 128 grams of purified water, mix and knead, and shape into a four-impeller-shaped carrier. After shaping, dry at 120°C for 4 hours and calcine at 700°C for 4 hours. This produces hydrogenation protective agent carrier A.

[0094] An impregnation solution containing molybdenum and cobalt was prepared, wherein the molybdenum source was ammonium molybdate and the cobalt source was cobalt nitrate. The molybdenum content in the impregnation solution, calculated as molybdenum oxide, was 3.16 g / 100 mL, and the cobalt content, calculated as cobalt oxide, was 0.74 g / 100 mL. A hydrogenation protective agent carrier A was impregnated with the molybdenum and cobalt-containing impregnation solution using a saturated impregnation method. After impregnation, the carrier was dried at 120°C for 4 hours and calcined at 500°C for 4 hours to produce the catalytic cracking oil slurry hydrogenation protective agent A of the present invention.

[0095] Take 100 grams of alumina trihydrate, 80 grams of pseudo-boehmite and 5 grams of sodium aluminate, add 260 grams of clean water, use a ball mill to grind, 450rpm, grind for 1 hour, the D50 of the particles in the slurry is 6.67μm. Add 1000 grams of clean water to the ground slurry and stir, then add 2 grams of citric acid, 10 grams of sodium hexametaphosphate, and 10 grams of silica sol. The pH value of the slurry is 9.41. The stirred slurry is transferred to an autoclave for hydrothermal treatment at a hydrothermal temperature of 230°C and a hydrothermal time of 5 hours. The material obtained after hydrothermal treatment is filtered, washed, and dried at 120°C for 5 hours to obtain alumina dry glue;

[0096] 100 g of the prepared alumina gel was added with 1 g of sesbania powder, 1 g of methylcellulose, 0.5 g of acetic acid, and 124 g of purified water, and the mixture was kneaded to form a four-leaf clover-shaped support. After forming, the support was dried at 120°C for 5 hours and calcined at 650°C for 4 hours to obtain a hydrogenation transition catalyst support A.

[0097] An impregnation solution containing molybdenum and cobalt was prepared, wherein the molybdenum source was ammonium molybdate and the cobalt source was cobalt nitrate. The content of molybdenum in the impregnation solution calculated as molybdenum oxide was 8.4 g / 100 mL, and the content of cobalt in the impregnation solution calculated as cobalt oxide was 2.0 g / 100 mL. The transition agent carrier A was impregnated with the above impregnation solution containing molybdenum and cobalt. After impregnation, the carrier was dried at 120° C. for 4 hours and calcined at 500° C. for 4 hours to obtain the catalytic cracking oil slurry hydrogenation transition catalyst A of the present invention.

[0098] The hydrodesulfurization catalyst used is the FZC-33 catalyst developed and produced by Sinopec Fushun Petrochemical Research Institute.

[0099] Catalyst evaluation:

[0100] A fixed-bed reactor was used, with the hydrogenation protective agent, hydrogenation transition catalyst, and hydrodesulfurization catalyst loaded at volume ratios of 25%, 35%, and 40%, respectively. The catalyst was vulcanized using a wet process, using dimethyl disulfide (DMDS) as the vulcanizing agent and straight-run diesel fuel, with the vulcanizing agent accounting for 1.5% of the diesel fuel's mass. The vulcanization process was conducted at a constant temperature of 230°C for 8 hours and 320°C for 8 hours.

[0101] The raw oil is a full-fraction slurry with a sulfur content of 1.15 wt% and a density (20°C) of 1.062 g / cm 3 The mass content of (three + four ring) aromatics is 48.1%. The process conditions evaluated are: reaction pressure 5.0 MPa, reaction temperature 350 ° C, hydrogen to oil volume ratio 1000, liquid hourly space velocity 0.8h -1 The results of the hydrotreated catalytic cracking slurry obtained after 200 hours of operation are listed in Tables 5 and 6, and the results of the hydrotreated catalytic cracking slurry obtained after 1500 hours of operation are listed in Tables 7 and 8.

[0102] Example 2

[0103] Compared with Example 1, the difference is that during the preparation of the alumina dry gel used in the hydrogenation protective agent, 90 grams of aluminum trihydrate, 100 grams of aluminum monohydrate, and 10 grams of sodium metaaluminate were taken, 300 grams of clean water were added, and ground using a ball mill. This produced the hydrogenation protective agent carrier B and the catalytic cracking oil slurry hydrogenation protective agent B of the present invention.

[0104] Compared with Example 1, the difference is that during the preparation of the alumina gel used in the hydrotransition catalyst, 80 grams of alumina trihydrate, 100 grams of alumina monohydrate, and 5 grams of sodium metaaluminate were taken, 260 grams of clean water were added, and ground using a ball mill. This produced the hydrotransition catalyst carrier B and the catalytic cracking oil slurry hydrotransition catalyst B of the present invention.

[0105] Catalyst evaluation:

[0106] Compared with Example 1, hydrogenation protectant B and hydrogenation transition catalyst B were used instead of hydrogenation protectant A and hydrogenation transition catalyst A, respectively. The results of the hydrotreated catalytic cracking slurry obtained after 200 hours of operation are listed in Tables 5 and 6, and the results of the hydrotreated catalytic cracking slurry obtained after 1500 hours of operation are listed in Tables 7 and 8.

[0107] Example 3

[0108] Compared with Example 1, the difference is that during the dry rubber preparation process, the stirred slurry of hydrogenation protective agent alumina is transferred into an autoclave for hydrothermal treatment at a temperature of 270°C and a hydrothermal time of 6 hours. Thus, the hydrogenation protective agent carrier C and catalytic cracking oil slurry hydrogenation protective agent C of the present invention are obtained.

[0109] Compared with Example 1, the difference is that during the dry rubber preparation process, the stirred slurry of the hydrogenation transition catalyst is transferred into an autoclave for hydrothermal treatment at a temperature of 270°C and a hydrothermal time of 6 hours. Thus, the hydrogenation transition catalyst carrier C and catalytic cracking oil slurry hydrogenation transition catalyst C of the present invention are obtained.

[0110] Catalyst evaluation:

[0111] Compared with Example 1, hydrogenation protectant C and hydrogenation transition catalyst C were used instead of hydrogenation protectant A and hydrogenation transition catalyst A, respectively. The results of the hydrotreated catalytic cracking slurry obtained after 200 hours of operation are listed in Tables 5 and 6, and the results of the hydrotreated catalytic cracking slurry obtained after 1500 hours of operation are listed in Tables 7 and 8.

[0112] Example 4

[0113] Compared with Example 1, the difference is that during the preparation of the alumina dry gel used as the hydrogenation protective agent, 100 grams of aluminum hydroxide, 90 grams of gibbsite, and 10 grams of aluminum sulfate were taken, added to 300 grams of clean water, and ground using a ball mill. 950 grams of clean water was added to the ground slurry and stirred. 5.5 grams of sodium hydroxide and 10 grams of sodium hexametaphosphate were then added, and the slurry pH value was 9.21. This produced the hydrogenation protective agent carrier D and the catalytic cracking oil slurry hydrogenation protective agent D of the present invention.

[0114] Compared with Example 1, the difference is that during the preparation of the alumina gel used in the hydrogenation transition catalyst, 100 grams of alumina trihydrate (commercially available), 80 grams of pseudo-boehmite, and 5 grams of aluminum sulfate were taken, added to 260 grams of clean water, and ground using a ball mill. The ground slurry was then added with 950 grams of clean water and stirred, and then 6 grams of sodium hydroxide and 10 grams of sodium hexametaphosphate were added. The slurry pH value was 9.60. The hydrogenation transition catalyst carrier D and catalytic cracking oil slurry hydrogenation transition catalyst D of the present invention were obtained.

[0115] Catalyst evaluation:

[0116] Compared with Example 1, hydrogenation protectant D and hydrogenation transition catalyst D were used instead of hydrogenation protectant A and hydrogenation transition catalyst A, respectively. The results of the hydrotreated catalytic cracking slurry obtained after 200 hours of operation are listed in Tables 5 and 6, and the results of the hydrotreated catalytic cracking slurry obtained after 1500 hours of operation are listed in Tables 7 and 8.

[0117] Example 5

[0118] Compared with Example 1, the difference is that during the preparation of the alumina dry gel used as the hydrogenation protective agent, 1100 grams of clean water is added to the ground slurry to obtain the hydrogenation protective agent carrier E and the catalytic cracking oil slurry hydrogenation protective agent E of the present invention.

[0119] Compared with Example 1, the difference is that during the preparation of the alumina dry gel used for the hydrogenation transition catalyst, 1100 grams of clean water was added to the ground slurry to obtain the hydrogenation transition agent carrier E and the catalytic cracking oil slurry hydrogenation transition agent E of the present invention.

[0120] Catalyst evaluation:

[0121] Compared with Example 1, hydrogenation protectant E and hydrogenation transition catalyst E were used instead of hydrogenation protectant A and hydrogenation transition catalyst A, respectively. The results of the hydrotreated catalytic cracking slurry obtained after 200 hours of operation are listed in Tables 5 and 6, and the results of the hydrotreated catalytic cracking slurry obtained after 1500 hours of operation are listed in Tables 7 and 8.

[0122] Example 6

[0123] Compared with Example 1, the difference is that the loading volume ratios of the hydrogenation protective agent, hydrogenation transition catalyst, and hydrodesulfurization catalyst are 20%, 35%, and 45%. The results of the hydrotreated catalytic cracking oil slurry obtained after 200 hours of operation are listed in Tables 5 and 6, and the results of the hydrotreated catalytic cracking oil slurry obtained after 1500 hours of operation are listed in Tables 7 and 8.

[0124] Comparative Example 1

[0125] Compared with Example 1, the hydrogenation protective agent, hydrogenation metal catalyst (instead of the hydrogenation transition catalyst) and hydrodesulfurization catalyst are FZC-12A, FZC-28 and FZC-33 catalysts developed and produced by Sinopec Fushun Petrochemical Research Institute, respectively, where the filling volume ratios of FZC-12A, FZC-28 and FZC-33 are 25%, 35% and 40%.

[0126] The results of the hydrotreated catalytic cracking slurry obtained after 200 hours of operation are listed in Tables 5 and 6, and the results of the hydrotreated catalytic cracking slurry obtained after 1500 hours of operation are listed in Tables 7 and 8.

[0127] Comparative Example 2

[0128] Compared to Example 1, the difference lies in that during the preparation of the alumina dry gel used as the hydrogenation protective agent, 100 g of aluminum hydroxide and 90 g of diaspore were added to 300 g of clean water and ground using a ball mill. The active metals were then impregnated, and the molybdenum oxide content in the solution was 4.63 g / 100 mL, and the cobalt oxide content was 1.08 g / 100 mL. This produced a comparative hydrogenation protective agent carrier DB and a comparative catalytic cracking oil slurry hydrogenation protective agent DB.

[0129] Compared to Example 1, the difference is that during the preparation of the alumina dry gel used in the hydrotransition catalyst, 100 g of alumina trihydrate and 80 g of pseudo-boehmite were added to 260 g of clean water and ground using a ball mill. When preparing the active metal solution, the molybdenum oxide content in the solution was 12.13 g / 100 mL, and the cobalt oxide content was 2.89 g / 100 mL. This produced a comparative hydrotransition catalyst support DB and a comparative catalytic cracking oil slurry hydrotransition catalyst DB.

[0130] Catalyst evaluation:

[0131] Compared with Example 1, hydrogenation protectant DB and hydrogenation transition catalyst DB were used instead of hydrogenation protectant A and hydrogenation transition catalyst A, respectively. The results of the hydrotreated catalytic cracking slurry obtained after 200 hours of operation are listed in Tables 5 and 6, and the results of the hydrotreated catalytic cracking slurry obtained after 1500 hours of operation are listed in Tables 7 and 8.

[0132] Comparative Example 3

[0133] Compared with Example 1, the difference in the preparation of the hydrogenation protective agent is that 950 g of purified water is added to the ground slurry and stirred, followed by the addition of 7 g of sulfuric acid, 5 g of sodium hexametaphosphate, and 10 g of Tween-80, resulting in a slurry pH of 2.06. The active metals are impregnated, and the molybdenum oxide content in the solution is 7.86 g / 100 mL, and the cobalt oxide content is 1.83 g / 100 mL. A comparative hydrogenation protective agent carrier DC and a comparative catalytic cracking oil slurry hydrogenation protective agent DC are produced.

[0134] Compared with Example 1, the difference is that during the preparation of the hydrogenation transition catalyst, 1000 grams of clean water is added to the ground slurry and stirred, and then 10 grams of sodium hydroxide, 10 grams of sodium hexametaphosphate, and 10 grams of silica sol are added, and the pH value of the slurry is 13.17; when preparing the active metal solution, the content of molybdenum oxide in the solution is 20.55 g / 100 mL, and the content of cobalt oxide is 4.89 g / 100 mL, to obtain a comparative catalytic cracking oil slurry hydrogenation transition catalyst carrier DC and a comparative catalytic cracking oil slurry hydrogenation transition catalyst DC.

[0135] Catalyst evaluation:

[0136] Compared with Example 1, hydrogenation protectant DC and hydrogenation transition catalyst DC were used instead of hydrogenation protectant A and hydrogenation transition catalyst A, respectively. The results of the hydrotreated catalytic cracking slurry obtained after 200 hours of operation are listed in Tables 5 and 6, and the results of the hydrotreated catalytic cracking slurry obtained after 1500 hours of operation are listed in Tables 7 and 8.

[0137] Table 1 Pore properties of hydrogenation protective agent carriers and protective agent compositions obtained in various examples

[0138]

[0139] Note: In the pore distribution of the carrier used in each example, (most probable pore diameter - 30) nm to (most probable pore diameter + 30) nm is a single peak, and the peak width is at least 60 nm.

[0140] Table 2 Pore properties and protective agent composition of the hydrogenation protective agent carrier obtained in each comparative example

[0141] serial number FZC-12A DB DC Carrier properties <![CDATA[Pore volume, cm 3 / g]]> 0.85 0.60 0.42 <![CDATA[Specific surface area, m 2 / g]]> 123 222 246 Most probable pore diameter, nm 17.5 9 4.5 Pore ​​size distribution range, nm 7～25 4～17.5 - The pore volume occupied by the concentrated pore size is the percentage of the total pore volume of the carrier, % 85 76 - Catalyst composition <![CDATA[MoO3,%]]> 3.80 3.75 3.74 CoO, % 0.91(NiO) 0.87 0.87

[0142] Table 3 Properties of the hydrotransition catalyst supports and catalyst compositions obtained in each example

[0143] serial number A B C D E Carrier properties <![CDATA[Mass percentage of the additive SiO2 in alumina, %]]> 2.41 2.39 2.41 2.44 2.40 <![CDATA[Pore volume, cm 3 / g]]> 1.14 1.17 1.21 1.19 1.12 <![CDATA[Specific surface area, m 2 / g]]> 177 173 164 166 181 The proportion of pore volume of 10-40nm to the total pore volume, % 30 27 23 25 33 The proportion of pore volume of 150~400nm in the total pore volume, % 38 40 46 42 35 Catalyst composition <![CDATA[MoO3,%]]> 8.78 8.78 8.79 8.79 8.78 CoO, % 2.09 2.09 2.10 2.09 2.09

[0144] Table 4 Properties of the Hydrogenation Transition Catalyst Supports and Catalyst Compositions of the Comparative Examples

[0145]

[0146]

[0147] *Note: The catalyst supports obtained in each comparative example are all unimodal.

[0148] Table 5 Evaluation results of various examples

[0149] serial number Example 1 Example 2 Example 3 Example 4 Example 5 <![CDATA[Hydrogenation product density (20 °C), g / cm 3 > 1.035 1.034 1.031 1.033 1.031 Desulfurization rate, % 74.3 74.5 74.9 74.7 75.3 (Three-ring + four-ring) aromatic hydrocarbon retention rate, % 94.6 94.5 94.2 94.4 94.0

[0150] Table 6 Evaluation results of each comparative example

[0151] serial number Comparative Example 1 Comparative Example 2 Comparative Example 3 <![CDATA[Hydrogenation product density (20 °C), g / cm 3 > 1.047 1.043 1.049 Desulfurization rate, % 70.9 72.7 68.6 (Three-ring + four-ring) aromatic hydrocarbon retention rate, % 95.6 95.1 96.2

[0152] Table 7 Evaluation results of various examples

[0153] serial number Example 1 Example 2 Example 3 Example 4 Example 5 <![CDATA[Hydrogenation product density (20 °C), g / cm 3 > 1.038 1.037 1.033 1.036 1.034 Desulfurization rate, % 72.0 72.2 72.6 72.4 73.0 (Three-ring + four-ring) aromatic hydrocarbon retention rate, % 94.8 94.7 94.4 94.6 94.2

[0154] Table 8 Evaluation results of each comparative example

[0155] serial number Comparative Example 1 Comparative Example 2 Comparative Example 3 <![CDATA[Hydrogenation product density (20 °C), g / cm 3 > 1.051 1.048 1.059 Desulfurization rate, % 67.3 67.5 58.9 (Three-ring + four-ring) aromatic hydrocarbon retention rate, % 95.9 95.6 97.1

[0156] In Tables 5-8, the aromatics retention rate is the percentage of three- and four-ring aromatics in the hydrogenation product relative to the three- and four-ring aromatics in the feedstock. Three- and four-ring aromatics are ideal feedstock aromatics for producing high-end carbon-based materials such as needle coke, and the aromatics retention rate is the ideal aromatics retention rate.

[0157] It can be seen from Tables 5-8 that, compared with the comparative agent and the conventional hydrogenation series catalyst, the use of the hydrogenation protective agent and the hydrogenation transition agent of the present invention in combination with the conventional hydrodesulfurization catalyst grading makes the catalyst system activity decay more slowly, the catalyst system has better desulfurization activity selectivity and stability, and has a greater degree of retention rate for tri-ring and tetra-ring aromatic hydrocarbons.

[0158] The above describes in detail the specific embodiments of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as the contents disclosed by the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for hydrotreating catalytic cracking oil slurry, using a fixed-bed hydrogenation process, comprising: In the presence of hydrogen, the catalytic cracking oil slurry feedstock is sequentially contacted with a hydrogenation protective agent, a hydrogenation transition catalyst and a hydrodesulfurization catalyst to carry out a hydrogenation reaction to obtain hydrogenated oil; The hydrogenation protective agent comprises a carrier and a hydrogenation active metal, wherein an alumina carrier is used, the hydrogenation active metal comprises molybdenum oxide and cobalt oxide, and the properties of the alumina carrier are as follows: the most probable pore diameter is 40 to 100 nm, preferably 50 to 70 nm, and the pore volume occupied by the pores from (most probable pore diameter - 30) nm to (most probable pore diameter + 30) nm accounts for more than 75% of the total pore volume, preferably 75% to 90%; The hydrogenation transition catalyst comprises an alumina carrier containing a promoter and MoO3 and CoO. The carrier has a bimodal pore size distribution, with smaller pore sizes concentrated in the range of 10 to 40 nm, and the pore volume of pores with a pore size of 10 to 40 nm accounting for 20% to 40% of the total pore volume; and larger pore sizes concentrated in the range of 150 to 400 nm, and the pore volume of pores with a pore size of 150 to 400 nm accounting for 30% to 50% of the total pore volume.

2. The method according to claim 1, characterized in that Based on the mass of the hydrogenation protective agent, the mass content of MoO3 is 2.0% to 7.0%, and the mass content of CoO is 0.3% to 1.7%; And / or, based on the mass of the hydrogenation transition catalyst, the content of MoO3 is 4.0% to 10.0%, and the content of CoO is 0.8% to 2.5%.

3. The method according to claim 1, characterized in that In the hydrogenation protective agent, the pore volume of the alumina support is 1.00 to 1.40 cm 3 / g, preferably 1.10 to 1.30 cm 3 / g, with a specific surface area of ​​120 to 180 m 2 / g, preferably 130 to 170 m 2 / g; And / or, in the hydrogenation transition catalyst, the pore volume of the carrier is 0.95 to 1.35 cm 3 / g, preferably 1.00 to 1.25 cm 3 / g, with a specific surface area of ​​110 to 175 m 2 / g, preferably 130 to 170 m 2 / g.

4. The method according to claim 1, wherein The shape of the hydrogenation protective agent is a four-leaf wheel or a four-leaf clover; and / or the shape of the hydrogenation transition catalyst is a four-leaf clover.

5. The method according to claim 1, wherein In the hydrogenation transition catalyst, the alumina carrier containing the promoter is one or more of fluorine, phosphorus, silicon or boron, preferably silicon; the content of the promoter as an element accounts for 0.2% to 10% of the total mass of the alumina in the carrier, preferably 1% to 6%.

6. The method according to claim 1, characterized in that The preparation method of the hydrogenation protective agent comprises the following steps: a) mixing a first aluminum source, a second aluminum source, and a third aluminum source with water to obtain a slurry, and then grinding the slurry; b) adding clean water to the slurry obtained in step a) and stirring; c) adding a modifier, a pH regulator, and an optional dispersant to the material obtained in step b) to obtain a mixed slurry, and then subjecting the mixed slurry to a hydrothermal treatment; d) drying the material obtained in step c) to obtain alumina dry glue; e) mixing the alumina dry glue obtained in step d) with a binder, shaping, drying, and calcining to obtain a carrier; f) impregnating the carrier obtained in step e) with an impregnation solution containing molybdenum and cobalt, and drying and calcining to obtain the hydrogenation protective agent.

7. The method according to claim 6, characterized in that In step a), the first aluminum source is aluminum trihydrate; the second aluminum source is alumina gel having a water content of 35% or less by mass, preferably aluminum monohydrate; the third aluminum source is an aluminum-containing salt compound, preferably at least one selected from aluminum nitrate, aluminum chloride, aluminum sulfate, and sodium metaaluminate; Preferably, in step a), the mass ratio of the first aluminum source, the second aluminum source and the third aluminum source is 30-66:33-60:1-10; Preferably, in step a), the amount of water added is 100% to 150% of the total mass of the first aluminum source, the second aluminum source and the third aluminum source; Preferably, in step a), the slurry is ground until the size of the particles in the slurry is 4 to 20 μm, measured by median particle size D50; Preferably, in step b), the slurry obtained in step a) is added with clean water and stirred so that the total mass content of the first aluminum source, the second aluminum source and the third aluminum source in the slurry is 10% to 20%.

8. The method according to claim 6 or 7, characterized in that In step c), the pH value of the mixed slurry is controlled to be 8.5 to 12.0; Preferably, in step c), the dispersant is a nonionic surfactant with an HLB value of 10 to 20, preferably at least one of Tween-80, lauryl alcohol polyoxyethylene ether, and methyl glucose polyoxyethylene ether; and / or the modifier is at least one of sodium hexametaphosphate, sodium tripolyphosphate, disodium ethylenediaminetetraacetic acid, sodium gluconate, sodium tartrate, etc.; Preferably, the amount of the modifier added is 0.01% to 6% of the mass of the material obtained in step b); and / or the amount of the dispersant added is less than 10% of the mass of the material obtained in step b), preferably 0.01% to 10%. Preferably, in step c), the conditions of the hydrothermal treatment are as follows: temperature of 220-280° C., time of 5-12 hours; Preferably, in step e), the drying temperature after forming is 100-180° C., and the drying time is 4-12 hours; the calcination temperature after forming is 500-800° C., and the calcination time is 3-12 hours.

9. The method according to claim 1, characterized in that The preparation method of the hydrogenation transition catalyst comprises the following steps: A) mixing a first aluminum source, a second aluminum source, and a third aluminum source with water to obtain a slurry, and then grinding the slurry; B) adding clean water to the slurry obtained in step A) and stirring; C) adding a pH regulator, a modifier, an auxiliary agent precursor, and an optional dispersant to the material obtained in step B) to obtain a mixed slurry, and then subjecting the mixed slurry to a hydrothermal treatment; D) drying the material obtained in step C) to obtain alumina dry gel; E) mixing the alumina dry gel obtained in step D) with a binder, shaping, drying, and calcining to obtain a carrier; F) impregnating the support obtained in step E) with an impregnation solution containing molybdenum and cobalt, and drying and calcining to obtain the hydrogenation transition catalyst.

10. The method according to claim 9, characterized in that In step A), the first aluminum source is aluminum trihydrate; the second aluminum source is alumina gel having a water content of 35% or less by mass, preferably aluminum monohydrate; the third aluminum source is an aluminum-containing salt compound, preferably at least one selected from aluminum nitrate, aluminum chloride, aluminum sulfate, and sodium metaaluminate; Preferably, in step A), the mass ratio of the first aluminum source, the second aluminum source, and the third aluminum source is 30-66:33-60:1-10; and / or, in step A), the amount of water added is 100% to 150% of the total mass of the first aluminum source, the second aluminum source, and the third aluminum source; Preferably, in step A), the slurry is ground until the size of the particles in the slurry is 4 to 20 μm, measured by the median particle size D50; Preferably, in step B), the slurry obtained in step A) is added with clean water and stirred so that the total mass content of the first aluminum source, the second aluminum source and the third aluminum source in the slurry is 10% to 20%.

11. The method according to claim 9 or 10, characterized in that In step C), the pH value of the mixed slurry in step C) is controlled to be in the range of 9.0 to 12.5; Preferably, in step C), the dispersant is a nonionic surfactant having an HLB value of 10 to 20, preferably at least one of Tween-80, lauryl alcohol polyoxyethylene ether, and methyl glucose polyoxyethylene ether; the amount of the dispersant added is less than 10% of the mass of the material obtained in step B), preferably 0.01% to 10%; Preferably, the modifier is at least one of sodium hexametaphosphate, sodium tripolyphosphate, disodium ethylenediaminetetraacetic acid, sodium gluconate, and sodium tartrate; and the amount of the modifier added is 0.01% to 10% of the mass of the material obtained in step B).

12. The preparation method according to claim 9, characterized in that: In step C), the auxiliary agent is one or more of fluorine, phosphorus, silicon or boron, preferably silicon; based on the total mass of the first aluminum source, the second aluminum source and the third aluminum source, the amount of the auxiliary agent added as an oxide is 0.2% to 10% of the total mass of the alumina, preferably 1% to 6%; preferably, the auxiliary fluorine precursor is at least one of hydrofluoric acid, ammonium fluoride, boron trifluoride, and sodium fluorosilicate, the auxiliary phosphorus precursor is at least one of phosphoric acid, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate, the auxiliary silicon precursor is at least one of silica sol, water glass, and fluorosilicic acid, and the auxiliary boron precursor is at least one of boric acid, sodium borate, ammonium borate, and ammonium metaborate.

13. The preparation method according to claim 9, characterized in that: In step C), the hydrothermal treatment conditions are as follows: a temperature of 200-260° C. and a hydrothermal time of 4-10 hours; and / or, in step E), the drying temperature after molding is 100-180° C. and the drying time is 4-12 hours; and the calcination temperature after molding is 500-800° C. and the calcination time is 3-12 hours.

14. The preparation method according to claim 1, characterized in that: The hydrodesulfurization catalyst is a residue oil hydrodesulfurization catalyst.

15. The preparation method according to claim 1, characterized in that: The percentages of the filling volumes of the hydrogenation protective agent, the hydrogenation transition catalyst and the hydrodesulfurization catalyst in the total filling volume are 3%-30%, 10%-40% and 30%-87%.

16. The preparation method according to claim 1, characterized in that: The catalytic cracking slurry oil raw material is one or more of full-fraction slurry oil minus second-line slurry oil and any fraction slurry oil.

17. The preparation method according to claim 1, characterized in that: The operating conditions of the hydrotreatment are as follows: reaction temperature of 300-400°C, reaction pressure of 1.0-10.0 MPa, hydrogen-to-oil volume ratio of 200:1-1200:1, liquid hourly volume space velocity of 0.1-2.0 h -1 .

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