A hydrofining catalyst, its preparation method and use

Abstract

The application discloses a kind of hydrofining catalyst and its preparation method and application.The method includes the following contents:(1) selecting or preparing alumina 1, introducing hydrogenation active metal into alumina 1;(2) selecting or preparing alumina 2, introducing hydrogenation active metal into alumina 2;(3) the material obtained in step (1) and the material obtained in step (2) are kneaded into final hydrofining catalyst;Wherein, the average pore size of alumina 1 is lower than the average pore size of alumina 2.The hydrofining catalyst prepared by the method can realize deep desulfurization for diesel oil raw material.

Description

Technical Field

[0001] This invention relates to a hydrorefining catalyst, its preparation method, and its application; more specifically, it relates to a highly active diesel hydrorefining catalyst, its preparation method, and its application. Background Technology

[0002] With increasingly stringent environmental regulations, countries and regions worldwide are imposing stricter requirements on gasoline and diesel vehicle emissions. To improve fuel oil quality and meet environmental standards, many countries have introduced stringent environmental regulations and gasoline and diesel quality standards. In recent years, my country has imposed even stricter limits on the sulfur, nitrogen, cetane number, and polycyclic aromatic hydrocarbon (PAH) content in refined diesel fuel. Developing efficient diesel desulfurization technologies to achieve ultra-deep desulfurization or conversion of diesel fuel has become a key challenge for countries around the world.

[0003] CN108452839A discloses a mesoporous / microporous composite molecular sieve, a catalyst, its preparation method, and its applications. The USY / MCM-48 mesoporous / microporous composite molecular sieve prepared by this invention has a mesoporous and microporous channel structure, with a mesoporous pore size distribution of 2.0–4.0 nm and a microporous pore size distribution of 0.3–1.0 nm. The catalyst uses a high specific surface area mesoporous / microporous molecular sieve as a support, which can effectively disperse the active components. Under the premise of low noble metal content, the catalyst still has high catalytic activity, and is particularly suitable for the selective ring-opening reaction of diesel aromatics.

[0004] CN108786928A discloses a diesel hydrotreating catalyst support and its preparation method. The method uses solid fiber filaments, modifying agents, and alumina as a support, which are then molded and calcined to obtain a modified diesel hydrotreating catalyst support with interconnected small and medium pores. This invention's support possesses interconnected small and medium pores and a higher specific surface area, thereby significantly improving the utilization rate of active centers, reducing mass transfer resistance, and ultimately achieving the goal of improving the catalyst's hydrodesulfurization, hydrodenitrogenation, and aromatic saturation performance.

[0005] CN102423712A discloses a method for preparing a highly active catalyst for the hydrorefining of low-quality diesel. The method involves using an inorganic acid as a precipitant, an amphoteric surfactant and a fluorinated compound as a composite dispersant, mixing them with a molding support, a salt solution of a Group VIB metal, an alcohol solvent, and water, followed by a solvothermal reaction at high temperature. After calcination, a fluorinated bimetallic catalyst is obtained. The prepared catalyst is then further dispersed with a salt solution containing a Group VIII metal, washed with water, filtered, dried, and calcined to obtain the catalyst for the hydrorefining of low-quality diesel. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a hydrorefining catalyst, its preparation method, and its application. The hydrorefining catalyst can achieve deep desulfurization of diesel feedstock.

[0007] The inventive concept of this invention is as follows: Dibenzothiophene sulfides are among the most difficult molecules to remove from diesel fuel, mainly due to their large molecular diameter, significant steric hindrance, and high diffusion resistance, making it difficult for them to contact the active sites on the catalyst surface and react. Therefore, improving the diffusion performance of the catalyst is a key challenge directly affecting the desulfurization activity of diesel hydrotreating catalysts. According to the Kelvin equation, the vapor pressure of reactants increases as their radius decreases. If supports with different pore sizes can be mixed, the vapor pressure difference between catalyst particles can be used to improve the diffusion performance of the catalyst, thereby improving the hydrodesulfurization performance of the diesel hydrotreating catalyst. Furthermore, the inventors have discovered that supports with smaller pore sizes have higher self-diffusion activation energies, while supports with larger pore sizes have lower self-diffusion activation energies. Therefore, selectively adapting different proportions of active metals can maximize the catalyst diffusion performance and the hydrodesulfurization activity of diesel fuel.

[0008] This invention discloses a method for preparing a hydrorefining catalyst, the method comprising the following steps:

[0009] (1) Select or prepare alumina 1, and introduce hydrogenated active metal into alumina 1;

[0010] (2) Select or prepare alumina 2, and introduce hydrogenated active metal into alumina 2;

[0011] (3) The materials obtained in step (1) and step (2) are mixed and kneaded to form the final hydrorefining catalyst;

[0012] Among them, the average pore size of alumina 1 is lower than that of alumina 2.

[0013] In the method of the present invention, the average pore size of alumina 1 is 2-12 nm lower than that of alumina 2, preferably 3-10 nm, and more preferably 4-8 nm.

[0014] In the method of the present invention, the average pore size of the alumina 1 is 2-5 nm, and the average pore size of the alumina 2 is 6-15 nm.

[0015] In the method of the present invention, the weight percentage of hydrogenated active metal introduced into alumina 1, calculated as oxide, is lower than the weight percentage of hydrogenated active metal introduced into alumina 2, calculated as oxide, with the weight basis being alumina 1 and alumina 2 loaded with hydrogenated active metal, respectively.

[0016] In the method of the present invention, the weight percentage of the hydrogenated active metal introduced into alumina 1, calculated as oxide, is 3-35 wt% lower than the weight percentage of the hydrogenated active metal introduced into alumina 2, calculated as oxide, preferably 4-32 wt%, and more preferably 5-20 wt%, with the weight basis being alumina 1 and alumina 2 loaded with hydrogenated active metal, respectively.

[0017] In the method of the present invention, based on the total weight of the material obtained in step (1), the content of hydrogenated active metal oxides loaded on the material obtained in step (1) is generally 0 to 20 wt%, preferably 2 to 18 wt%, and more preferably 4 to 16 wt%; wherein the content of group VII or group VIII hydrogenated active metal oxides is generally 0 to 5 wt%, preferably 0.5 to 4.5 wt%, and the content of group VI hydrogenated active metal oxides is generally 0 to 15 wt%, preferably 1.5 to 12.5 wt%.

[0018] In the method of the present invention, based on the total weight of the material obtained in step (2), the content of hydrogenated active metal oxides loaded on the material obtained in step (2) is generally 5 to 40 wt%, preferably 8 to 38 wt%, and more preferably 10 to 35 wt%; wherein the content of Group VII or Group VIII hydrogenated active metal oxides is generally 2 to 10 wt%, preferably 3 to 8 wt%; and the content of Group VI hydrogenated active metal oxides is generally 2 to 30 wt%, preferably 5 to 25 wt%.

[0019] In the method of the present invention, the percentage of the material obtained in step (1) as a percentage of the final hydrorefining catalyst weight is lower than the percentage of the material obtained in step (2) as a percentage of the final hydrorefining catalyst weight, and the difference between the two is 20-90 wt%, preferably 25-80 wt%, and more preferably 30-70 wt%.

[0020] In the method of the present invention, the material obtained in step (1) accounts for 5 to 40 wt% of the total weight of the final hydrorefining catalyst, preferably 8 to 38 wt%, and more preferably 15 to 35 wt%; the material obtained in step (2) accounts for 60 to 95 wt% of the total weight of the final hydrorefining catalyst, preferably 62 to 90 wt%, and more preferably 65 to 85 wt%.

[0021] In the method of the present invention, the hydrogenated active metal includes Group VI, Group VII, Group VIII metals or their metal oxides or metal sulfides, more preferably one or more of iron, chromium, molybdenum, tungsten, cobalt, nickel or their sulfides or oxides.

[0022] In the method of this invention, the hydrogenated active metal is introduced in step (1) and / or step (2) by impregnation, which involves loading the hydrogenated active metal onto alumina 1 and / or 2. Equal-volume impregnation or excessive impregnation can be used; stepwise impregnation or co-impregnation can also be used, but equal-volume stepwise impregnation is preferred. When using stepwise loading of the active component, Group VI active components should be loaded first, followed by Group VII or Group VIII active metals. After impregnation, the metal is allowed to stand for 6–24 hours to air dry, then placed in an oven at 60–140°C for 4–14 hours, and calcined in a muffle furnace at 400–600°C for 4–12 hours.

[0023] In the method of this invention, the materials obtained in step (1) and step (2), along with the additives and binders, are mixed and kneaded. The binder is typically porous alumina or silica, and its mass fraction is 5%–25 wt%, preferably 6–20 wt%, and more preferably 8–15 wt%, based on the total weight of the kneaded materials. The additives are typically ethylenediaminetetraacetic acid, citric acid, ammonium triacetate, tartaric acid, malic acid, etc., and their mass fraction is 5%–15 wt%, preferably 6–13 wt%, and more preferably 7–12 wt%, based on the total weight of the kneaded materials. Subsequently, the mixture is dried at 60–140°C for 2–14 h and calcined at 400–600°C for 2–12 h to obtain the catalyst product.

[0024] A hydrorefining catalyst prepared by the above method, based on the total weight of the final hydrorefining catalyst, has a hydrorefining active metal content of 15-50 wt%, calculated as oxides, wherein the content of Group VII or Group VIII active metals is typically 3-10 wt%, and the content of Group VI active metals is typically 10-40 wt%.

[0025] The present invention relates to a hydrorefining catalyst, wherein the shape of the hydrorefining catalyst support can be a toothed ball, a clover, a four-leaf clover, or a cylindrical strip. The diameter of the toothed ball catalyst is 1.5–8.5 mm; the length of the clover, four-leaf clover, or cylindrical strip is 1.0–10.0 mm, and the diameter is 1.0–5.5 mm.

[0026] The hydrorefining catalyst of this invention is suitable for diesel hydrorefining processes, wherein the reaction conditions in the refining reaction zone are generally: reaction pressure 4.0–15.0 MPa, preferably 6.0–12.0 MPa; average reaction temperature 280–430 °C, preferably 300–400 °C; and volume hourly space velocity (VHSV) 0.5–3.0 h⁻¹. -1 Preferably 0.6–2.5 h -1 .

[0027] Compared with the prior art, the beneficial effects of the method of the present invention are as follows:

[0028] 1. By mixing carriers with different pore sizes, the vapor pressure difference between the outer surfaces of the carriers can be used to promote the diffusion and reaction of sulfide molecules, thereby improving the diffusion performance of diesel hydrotreating catalysts.

[0029] 2. Depending on the pore size and diffusion activation energy of different carriers, loading different amounts of active metals onto carriers with different pore sizes can significantly improve the desulfurization and denitrification effects. Detailed Implementation

[0030] The following examples and comparative examples further illustrate the hydrorefining catalyst, its preparation method, and its application provided by the present invention, but do not limit the present invention.

[0031] Table 1 Properties of Crude Oil

[0032] Crude oil name diesel fuel <![CDATA[Density (20 °C), g·cm -3 (GB / T 1884)]]> 0.8150 Distillation range, °C (ASTM D1160) IBP~EBP 195～360 Sulfur content, ppm 11000 Nitrogen content, ppm 380 Group composition, wt% (SH / T 0606) Total alkanes 41.0 Total cycloalkanes 33.5 Total aromatics 25.5

[0033] Table 2 Evaluation Criteria

[0034] Pressure, MPa 6.0 <![CDATA[Refining agent mass space velocity, h -1 > 1.0 Hydrogen-to-oil ratio at the inlet of the hydrorefining reaction zone, v / v 400:1 Refining reaction temperature, °C 380 Runtime, h 200

[0035] The feedstock used in the following examples and comparative examples is diesel oil, the properties of which are shown in Table 1. The catalyst evaluation conditions in all examples and comparative examples are the same, as shown in Table 2.

[0036] This embodiment uses five catalysts with different properties, and their synthesis methods are as follows.

[0037] Example 1

[0038] Two types of alumina with different average pore sizes were used as supports: the smallest pore size support had an average pore size of 2.5 nm, and the largest pore size support had an average pore size of 8.5 nm. Using the smallest pore size alumina as the support, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to air dry, then dried in an oven at 120℃ for 6 hours, and finally calcined in a muffle furnace at 450℃ for 6 hours to obtain catalyst-A powder. Based on the alumina with supported active metals, the nickel active metal loading in catalyst-A was 1.5 wt%, and the molybdenum active metal loading was 6.0 wt%.

[0039] Using alumina with the largest pore size as a carrier, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 6 hours to air dry, then dried in an oven at 100℃ for 6 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-B powder. Based on the alumina supporting the active metals, the nickel active metal loading in catalyst-B was 3.5 wt%, and the molybdenum active metal loading was 15.0 wt%.

[0040] Finally, catalyst-A powder and catalyst-B powder were mechanically mixed, and then a certain amount of additives and binders were added and extruded. Based on the final total weight of the catalyst, the amount of ethylenediaminetetraacetic acid additive added was 6.0 wt%, and the amount of alumina binder added was 8.0 wt%. After drying at 100℃ for 6 h and calcining at 500℃ for 4 h, catalyst 1 was obtained, in which the mass fraction of catalyst-A was 30 wt% and the mass fraction of catalyst-B was 62 wt%.

[0041] Catalyst 1 synthesized by the above method was selected as the diesel hydrorefining catalyst. Using the diesel in Table 1 as raw material, the catalyst was evaluated for 200 hours according to the conditions in Table 2. Finally, the sulfur content of the hydrorefined diesel was analyzed.

[0042] Example 2

[0043] Two types of alumina with different average pore sizes were used as supports: the smallest pore size support had an average pore size of 3.5 nm, and the largest pore size support had an average pore size of 9.5 nm. Using the smallest pore size alumina as the support, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to air dry, then dried in an oven at 120℃ for 6 hours, and finally calcined in a muffle furnace at 450℃ for 6 hours to obtain catalyst-A powder. Based on the alumina with supported active metals, the nickel active metal loading in catalyst-A was 1.0 wt%, and the molybdenum active metal loading was 3.0 wt%.

[0044] Using alumina with the largest pore size as a carrier, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to air dry, then dried in an oven at 120℃ for 6 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-B powder. Based on the alumina supporting the active metals, the nickel active metal loading in catalyst-B was 3.0 wt%, and the molybdenum active metal loading was 12.0 wt%.

[0045] Finally, catalyst-A powder and catalyst-B powder were mechanically mixed, and then a certain amount of additives and binders were added and extruded. Based on the final total weight of the catalyst, the amount of ethylenediaminetetraacetic acid additive added was 7.5 wt%, and the amount of alumina binder added was 10.0 wt%. After drying at 120℃ for 4 h and calcining at 500℃ for 6 h, catalyst 2 was obtained, in which the mass fraction of catalyst-A was 30.0 wt% and the mass fraction of catalyst-B was 60.0 wt%.

[0046] Catalyst 2, synthesized by the above method, was selected as the diesel hydrorefining catalyst. Using the diesel in Table 1 as raw material, the catalyst was evaluated for 200 hours according to the conditions in Table 2. Finally, the sulfur content of the hydrorefined diesel was analyzed.

[0047] Example 3

[0048] Two types of alumina with different average pore sizes were used as supports: the smallest pore size support had an average pore size of 4.5 nm, and the largest pore size support had an average pore size of 10.5 nm. Using the smallest pore size alumina as the support, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the powder was allowed to stand for 10 hours to air dry, then dried in an oven at 100℃ for 6 hours, and finally calcined in a muffle furnace at 500℃ for 4 hours to obtain catalyst-A powder. Based on the alumina with supported active metals, the nickel active metal loading in catalyst-A was 2.0 wt%, and the molybdenum active metal loading was 6.0 wt%.

[0049] Using alumina with the largest pore size as a carrier, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to air dry, then dried in an oven at 120℃ for 6 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-B powder. Based on the alumina supporting the active metals, the nickel active metal loading in catalyst-B was 5.0 wt%, and the molybdenum active metal loading was 22.0 wt%.

[0050] Finally, catalyst-A powder and catalyst-B powder were mechanically mixed to obtain catalyst 3, which was then extruded with a certain amount of additives and binders. Based on the final total weight of the catalyst, the amount of ethylenediaminetetraacetic acid additive added was 10.0 wt%, and the amount of alumina binder added was 8.0 wt%. After drying at 80℃ for 10 h and calcining at 500℃ for 4 h, catalyst 3 was obtained, in which the mass fraction of catalyst-A was 25.0 wt% and the mass fraction of catalyst-B was 65.0 wt%.

[0051] Catalyst 3, synthesized by the above method, was selected as the diesel hydrorefining catalyst. Using the diesel in Table 1 as raw material, the catalyst was evaluated for 200 hours according to the conditions in Table 2. Finally, the sulfur content of the hydrorefined diesel was analyzed.

[0052] Example 4

[0053] Two types of alumina with different average pore sizes were used as carriers. The carrier with the smallest pore size had an average pore size of 3.5 nm, while the carrier with the largest pore size had an average pore size of 11.5 nm.

[0054] Using alumina with the smallest pore size as a carrier, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to air dry, then dried in an oven at 100℃ for 8 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-A powder. Based on the alumina supporting the active metals, the nickel active metal loading in catalyst-A was 2.0 wt%, and the molybdenum active metal loading was 6.0 wt%.

[0055] Using alumina with the largest pore size as a carrier, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to air dry, then dried in an oven at 100℃ for 6 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-B powder. Based on the alumina supporting the active metals, the nickel active metal loading in catalyst-B was 4.5 wt%, and the molybdenum active metal loading was 12.5 wt%.

[0056] Finally, catalyst-A powder and catalyst-B powder were mechanically mixed, and then a certain amount of additives and binders were added and extruded. Based on the final total weight of the catalyst, the amount of ethylenediaminetetraacetic acid additive added was 7.0 wt%, and the amount of alumina binder added was 6.0 wt%. After drying at 80℃ for 12 h and calcining at 500℃ for 6 h, catalyst 4 was obtained, in which the mass fraction of catalyst-A was 15 wt% and the mass fraction of catalyst-B was 79 wt%.

[0057] Catalyst 4, synthesized by the above method, was selected as the diesel hydrorefining catalyst. Using the diesel in Table 1 as raw material, the catalyst was evaluated for 200 hours according to the conditions in Table 2. Finally, the sulfur content of the hydrorefined diesel was analyzed.

[0058] Example 5

[0059] Two types of alumina with different average pore sizes were used as carriers. The carrier with the smallest pore size had an average pore size of 3.5 nm, while the carrier with the largest pore size had an average pore size of 11.5 nm.

[0060] Using alumina with the smallest pore size as a carrier, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 6 hours to air dry, then dried in an oven at 120℃ for 6 hours, and finally calcined in a muffle furnace at 550℃ for 4 hours to obtain catalyst-A powder. Based on the alumina supporting the active metals, the nickel active metal loading in catalyst-A was 3.0 wt%, and the molybdenum active metal loading was 7.0 wt%.

[0061] Using alumina with the largest pore size as a carrier, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 6 hours to air dry, then dried in an oven at 120℃ for 8 hours, and finally calcined in a muffle furnace at 550℃ for 6 hours to obtain catalyst-B powder. Based on the alumina supporting the active metals, the nickel active metal loading in catalyst-B was 4.5 wt%, and the molybdenum active metal loading was 17.5 wt%.

[0062] Finally, catalyst-A powder and catalyst-B powder were mechanically mixed, and then a certain amount of additives and binders were added and extruded. Based on the final total weight of the catalyst, the amount of ethylenediaminetetraacetic acid additive added was 6.0 wt%, and the amount of alumina binder added was 7.0 wt%. After drying at 80℃ for 12 h and calcining at 500℃ for 6 h, catalyst 5 was obtained, in which the mass fraction of catalyst-A was 14 wt% and the mass fraction of catalyst-B was 79 wt%.

[0063] Catalyst 5, synthesized by the above method, was selected as the diesel hydrorefining catalyst. Using the diesel in Table 1 as raw material, the catalyst was evaluated for 200 hours according to the conditions in Table 2. Finally, the sulfur content of the hydrorefined diesel was analyzed.

[0064] Comparative Example 1

[0065] Using microporous alumina with an average pore size of 2.5 nm as a carrier, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to air dry, then dried in an oven at 120℃ for 6 hours, and finally calcined in a muffle furnace at 450℃ for 6 hours to obtain catalyst-A powder. Based on the alumina loaded with active metals, the nickel active metal loading in catalyst-A was 1.5 wt%, and the molybdenum active metal loading was 6.0 wt%.

[0066] Using microporous alumina with an average pore size of 2.5 nm as a carrier, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 6 hours to air dry, then dried in an oven at 100℃ for 6 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-B powder. Based on the alumina loaded with active metals, the nickel active metal loading in catalyst-B was 3.5 wt%, and the molybdenum active metal loading was 15.0 wt%.

[0067] Finally, catalyst-A powder and catalyst-B powder were mechanically mixed, and then a certain amount of additives and binders were added and extruded. Based on the final total weight of the catalyst, the amount of ethylenediaminetetraacetic acid additive added was 6.0 wt%, and the amount of alumina binder added was 8.0 wt%. After drying at 100℃ for 6 h and calcining at 500℃ for 4 h, catalyst 5 was obtained, in which the mass fraction of catalyst-A was 30 wt% and the mass fraction of catalyst-B was 62 wt%.

[0068] Catalyst 6, synthesized by the above method, was selected as the diesel hydrorefining catalyst. Using the diesel in Table 1 as raw material, the catalyst was evaluated for 200 hours according to the conditions in Table 2. Finally, the sulfur content of the hydrorefined diesel was analyzed.

[0069] Comparative Example 2

[0070] Using macroporous alumina with an average pore size of 8.5 nm as a support, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to air dry, then dried in an oven at 120℃ for 6 hours, and finally calcined in a muffle furnace at 450℃ for 6 hours to obtain catalyst-A powder. Based on the alumina loaded with active metals, the nickel active metal loading in catalyst-A was 1.5 wt%, and the molybdenum active metal loading was 6.0 wt%.

[0071] Using macroporous alumina with an average pore size of 8.5 nm as a carrier, molybdenum and nickel active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 6 hours to air dry, then dried in an oven at 100℃ for 6 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-B powder. Based on the alumina loaded with active metals, the nickel active metal loading in catalyst-B was 3.5 wt%, and the molybdenum active metal loading was 15.0 wt%.

[0072] Finally, catalyst-A powder and catalyst-B powder were mechanically mixed, and then a certain amount of additives and binders were added and extruded. Based on the final total weight of the catalyst, the amount of ethylenediaminetetraacetic acid additive added was 6.0 wt%, and the amount of alumina binder added was 8.0 wt%. After drying at 100℃ for 6 h and calcining at 500℃ for 4 h, catalyst 7 was obtained, in which the mass fraction of catalyst-A was 30 wt% and the mass fraction of catalyst-B was 62 wt%.

[0073] Catalyst 7, synthesized by the above method, was selected as the diesel hydrorefining catalyst. Using the diesel in Table 1 as raw material, the catalyst was evaluated for 200 hours according to the conditions in Table 2. Finally, the sulfur content of the hydrorefined diesel was analyzed.

[0074] Table 3. Test Results of Examples

[0075] project Example 1 Example 2 Example 3 Example 4 Example 5 Sulfur content of refined diesel oil, ppm 1.8 1.5 1.9 2.8 8.5 Nitrogen content of refined diesel fuel, ppm 3.8 3.6 4.1 5.3 10.2

[0076] Table 4. Results of the comparative experiment

[0077] project Comparative Example 1 Comparative Example 2 Sulfur content of refined diesel oil, ppm 20.8 15.8 Nitrogen content of refined diesel fuel, ppm 32.5 21.9

[0078] As can be seen from the experimental results of the comparative examples and embodiments in Tables 3 and 4, the diesel hydrorefining catalyst of this patent invention, under the same reaction conditions, has lower sulfur and nitrogen content in the hydrorefined diesel products compared with the comparative examples, indicating that the catalyst of this patent invention has good hydrodesulfurization and denitrification activity.

Claims

1. A method for preparing a hydrorefining catalyst for diesel hydrorefining, characterized in that: The method includes the following: (1) Select or prepare alumina 1, introduce hydrogenated active metal into alumina 1, and obtain the material; (2) Select or prepare alumina 2, introduce hydrogenated active metal into alumina 2, and obtain the material; (3) The materials obtained in step (1) and step (2) are mixed and kneaded to form the final hydrorefining catalyst; wherein the materials obtained in step (1) and step (2) are powders. The average pore size of alumina 1 is 2-12 nm lower than that of alumina 2. The mass percentage of hydrogenated active metal introduced into alumina 1, expressed as an oxide, is 3-35 wt% lower than that of hydrogenated active metal introduced into alumina 2, expressed as an oxide. The weight basis is based on alumina 1 loaded with hydrogenated active metal and alumina 2 loaded with hydrogenated active metal, respectively. Based on the total weight of the material obtained in step (1), the content of hydrogenated active metal oxide loaded in the material obtained in step (1) is 2-20 wt%. The material obtained in step (1) accounts for 5 to 40 wt% of the total weight of the final hydrorefining catalyst; the material obtained in step (2) accounts for 60 to 95 wt% of the total weight of the final hydrorefining catalyst.

2. The method according to claim 1, characterized in that: The average pore size of alumina 1 is 3-10 nm smaller than that of alumina 2.

3. The method according to claim 2, characterized in that: The average pore size of alumina 1 is 4-8 nm smaller than that of alumina 2.

4. The method according to claim 1, characterized in that: The alumina 1 has an average pore size of 2-5 nm, and the alumina 2 has an average pore size of 6-15 nm.

5. The method according to claim 4, characterized in that: The mass percentage of hydrogenated active metal introduced into alumina 1, expressed as an oxide, is 4 to 32 wt% lower than that of hydrogenated active metal introduced into alumina 2, expressed as an oxide. The weight basis is based on alumina 1 loaded with hydrogenated active metal and alumina 2 loaded with hydrogenated active metal, respectively.

6. The method according to claim 5, characterized in that: The mass percentage of hydrogenated active metal introduced into alumina 1, expressed as an oxide, is 5-20 wt% lower than that of hydrogenated active metal introduced into alumina 2, expressed as an oxide. The weight basis is based on alumina 1 loaded with hydrogenated active metal and alumina 2 loaded with hydrogenated active metal, respectively.

7. The method according to claim 1, characterized in that: The material obtained in step (1) accounts for 8 to 38 wt% of the total weight of the final hydrorefining catalyst; the material obtained in step (2) accounts for 62 to 90 wt% of the total weight of the final hydrorefining catalyst.

8. The method according to claim 7, characterized in that: The material obtained in step (1) accounts for 15 to 35 wt% of the total weight of the final hydrorefining catalyst; the material obtained in step (2) accounts for 65 to 85 wt% of the total weight of the final hydrorefining catalyst.

9. The method according to claim 1, characterized in that: Hydrogen-active metals include Group VI, Group VII, and Group VIII metals or their metal oxides or metal sulfides.

10. The method according to claim 9, characterized in that: The active metal for hydrogenation is one or more of iron, chromium, molybdenum, tungsten, cobalt, nickel, or their sulfides or oxides.

11. The method according to claim 9, characterized in that: Based on the total weight of the material obtained in step (1), the content of hydrogenated active metal oxides loaded on the material obtained in step (1) is 2 to 18 wt%; wherein the content of group VII or group VIII hydrogenated active metal oxides is 0.5 to 5 wt%, and the content of group VI hydrogenated active metal oxides is 1.5 to 15 wt%.

12. The method according to claim 11, characterized in that: Based on the total weight of the material obtained in step (1), the content of hydrogenated active metal oxides loaded in the material obtained in step (1) is 4 to 16 wt%; wherein the content of group VII or group VIII hydrogenated active metal oxides is 0.5 to 4.5 wt%, and the content of group VI hydrogenated active metal oxides is 1.5 to 12.5 wt%.

13. The method according to claim 9, characterized in that: Based on the total weight of the material obtained in step (2), the content of hydrogenated active metal oxides loaded on the material obtained in step (2) is 5 to 40 wt%; of which the content of group VII or group VIII hydrogenated active metal oxides is 2 to 10 wt%; and the content of group VI hydrogenated active metal oxides is 2 to 30 wt%.

14. The method according to claim 13, characterized in that: Based on the total weight of the material obtained in step (2), the content of hydrogenated active metal oxides loaded on the material obtained in step (2) is 8 to 38 wt%; of which the content of group VII or group VIII hydrogenated active metal oxides is 3 to 8 wt%; and the content of group VI hydrogenated active metal oxides is 5 to 25 wt%.

15. The method according to claim 13, characterized in that: Based on the total weight of the material obtained in step (2), the content of hydrogenated active metal oxides loaded in the material obtained in step (2) is 10-35 wt%.

16. The method according to claim 1, characterized in that: The hydrogenated active metal is introduced in step (1) and / or step (2) by impregnation.

17. The method according to claim 16, characterized in that: The impregnation method involves impregnation of equal or excessive volume, followed by standing for 6–24 hours to air dry, then drying in an oven at 60–140°C for 4–14 hours, and finally calcining in a muffle furnace at 400–600°C for 4–12 hours.

18. A hydrorefining catalyst prepared by any one of the methods described in claims 1-17, characterized in that: Based on the total weight of the final hydrorefining catalyst, the content of the hydrorefining active metal, calculated as oxide, is 15–50 wt%, of which the content of Group VII or Group VIII active metals is 3–10 wt%, and the content of Group VI active metals is 10–40 wt%.

19. The application of the catalyst according to claim 18 in diesel hydrorefining, characterized in that: The reaction pressure was 4.0–15.0 MPa; the average reaction temperature was 280–430 °C; and the volume hourly space velocity (VHSV) was 0.5–3.0 h⁻¹. -1 .

20. The application of the catalyst according to claim 19 in diesel hydrorefining, characterized in that: The reaction pressure was 6.0–12.0 MPa; the average reaction temperature was 300–400 °C; and the volume hourly space velocity was 0.6–2.5 h⁻¹. -1 .