A diesel hydrocracking catalyst, its preparation method and application

Abstract

This invention provides a method for preparing a diesel hydrocracking catalyst, comprising the following steps: mixing and kneading a Y-type molecular sieve loaded with a hydrogenation active metal and alumina loaded with a hydrogenation active metal to obtain the final hydrocracking catalyst; wherein the average pore size of the alumina is larger than the average pore size of the Y-type molecular sieve. The catalyst prepared by this method can improve the diffusion performance of macromolecules in low-quality diesel fuel within the molecular sieve channels, enhance catalytic activity, reduce reaction temperature, decrease energy consumption, and extend the operating cycle of the equipment.

Description

Technical Field

[0001] This invention relates to a diesel hydrocracking catalyst, its preparation method, and its application. It is particularly suitable for the process of producing high value-added products from low-quality diesel hydrocracking, and can achieve the purpose of reducing the cracking reaction temperature and extending the operating cycle of the unit. Background Technology

[0002] Hydrocracking technology is a clean fuel oil and chemical feedstock production technology. It can process low-quality feedstocks such as vacuum gas oil, catalytic diesel, coking gas oil, coking diesel, fluidized bed gas oil, and fluidized bed diesel to produce light naphtha, heavy naphtha, jet fuel, diesel, and high-quality tail oil. In recent years, the diesel consumption market has been sluggish, the diesel-to-gasoline ratio has continued to decline, and gasoline demand has been on the rise. Therefore, the current product structure adjustment direction of Chinese refineries is to shift from producing traditional low-value-added, low-quality diesel feedstocks to producing high-value-added gasoline or BTX products, which can solve the problems of diesel oversupply and insufficient gasoline and aromatics production in refineries.

[0003] The biggest technical shortcomings of the hydrocracking technology for producing gasoline or BTX from inferior diesel are the high reaction temperature, rapid catalyst deactivation rate, and short operating cycle. Therefore, developing highly active and stable hydrocracking catalysts is of great significance for extending the operating cycle of inferior diesel hydrocracking units and improving the economic benefits of enterprises.

[0004] CN106669789A discloses a method for preparing a catalytic diesel hydrocracking catalyst. This method involves calcining a deactivated hydrocracking catalyst in an oxygen-containing atmosphere to partially decarbonize it, obtaining a decarbonized catalyst. This decarbonized catalyst powder is then pulverized. Subsequently, the sieved powder, hydrocracking catalyst support material, and hydrocracking active metal precursor are mixed and treated at high temperature in an inert atmosphere to obtain the catalytic diesel hydrocracking catalyst. While this catalyst can solve the problem of long initial equilibrium time in catalytic diesel hydroconversion units, it suffers from high carbon buildup and a faster deactivation rate, compromising the unit's operational cycle. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to improve the diffusion performance of macromolecules in inferior diesel oil in the molecular sieve channels, so as to improve catalytic reaction activity, reduce reaction temperature, reduce energy consumption and extend the operation cycle of the device.

[0006] This invention discloses a method for preparing a diesel hydrocracking catalyst, the method comprising: mixing and molding a Y molecular sieve loaded with a hydrogenation active metal and alumina loaded with a hydrogenation active metal to obtain the final hydrocracking catalyst; wherein the average pore size of the alumina is larger than the average pore size of the Y molecular sieve.

[0007] In the preparation method of the catalyst of the present invention, the final hydrocracking catalyst is obtained by mixing and kneading Y molecular sieve 1 loaded with hydrogenation active metal, Y molecular sieve 2 loaded with hydrogenation active metal, and alumina loaded with hydrogenation active metal; the pore size of Y molecular sieve 1 is smaller than that of Y molecular sieve 2, and the pore size of alumina is larger than the average pore size of Y molecular sieve 2, based on the unloaded metal support.

[0008] In the preparation method of the catalyst of the present invention, the average pore size of the Y molecular sieve 1 is 1-7 nm lower than that of the Y molecular sieve 2, preferably 2-6 nm, and more preferably 3-5 nm.

[0009] In the preparation method of the catalyst of the present invention, the average pore size of the alumina is 2-10 nm higher than that of the molecular sieve 2, preferably 3-8 nm, and more preferably 4-6 nm.

[0010] In the preparation method of the catalyst of the present invention, the average pore size of the Y molecular sieve 1 is 1-5 nm, preferably 2-4 nm; the average pore size of the Y molecular sieve 2 is 3-10 nm, preferably 4-8 nm; and the average pore size of the alumina is 6-20 nm, preferably 8-16 nm.

[0011] In the preparation method of the catalyst of the present invention, the weight content of the hydrogenated active metal in the Y molecular sieve 1 supported with hydrogenated active metal, based on its weight, is lower than the weight content of the hydrogenated active metal in the Y molecular sieve 2 supported with hydrogenated active metal, based on its weight, based on its weight, based on its weight; the difference between the two is 5 to 35 wt%, preferably 10 to 30 wt%, and more preferably 15 to 25 wt%.

[0012] In the preparation method of the catalyst of the present invention, the weight content of the hydrogenated active metal in the Y molecular sieve 2 supported by hydrogenated active metal (calculated as oxide) is lower than the weight content of the hydrogenated active metal in the alumina supported by hydrogenated active metal (calculated as oxide); the difference between the two is 5 to 40 wt%, preferably 8 to 36 wt%, and more preferably 10 to 30 wt%.

[0013] In the preparation method of the catalyst of the present invention, the Y molecular sieve 1 supported on hydrogenation active metal accounts for 3 to 20 wt% of the total weight of the final hydrocracking catalyst, preferably 5 to 18 wt%; the Y molecular sieve 2 supported on hydrogenation active metal accounts for 10 to 40 wt% of the total weight of the final hydrocracking catalyst, preferably 12 to 35 wt%; and the alumina supported on hydrogenation active metal accounts for 20 to 65 wt% of the total weight of the final hydrocracking catalyst, preferably 25 to 55 wt%.

[0014] In the preparation method of the catalyst of the present invention, the hydrogenation 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.

[0015] In the preparation method of the catalyst of the present invention, based on the total weight of the Y molecular sieve 1 loaded with hydrogenated active metal, the content of the hydrogenated active metal in the Y molecular sieve 1 loaded with hydrogenated active metal, calculated as oxide, is generally 0-15 wt%, preferably 2-12 wt%; wherein the content of Group VII or Group VIII hydrogenated active metal oxide is generally 0-5 wt%, preferably 1-4 wt%, and the content of Group VI hydrogenated active metal, calculated as oxide, is generally 0-10 wt%, preferably 2-8 wt%.

[0016] In the preparation method of the catalyst of the present invention, based on the total weight of the Y molecular sieve 2 loaded with hydrogenated active metal, the content of the hydrogenated active metal in the Y molecular sieve 2 as an oxide is generally 2-30 wt%, preferably 5-26 wt%; wherein the content of Group VII or Group VIII hydrogenated active metal as an oxide is generally 1-8 wt%, preferably 2-6 wt%; and the content of Group VI hydrogenated active metal as an oxide is generally 1-25 wt%, preferably 3-22 wt%.

[0017] In the preparation method of the catalyst of the present invention, based on the total weight of the alumina loaded with hydrogenated active metals, the content of the hydrogenated active metals in the alumina loaded with hydrogenated active metals, calculated as oxides, is generally 3-42 wt%, preferably 8-35 wt%; wherein the content of Group VII or Group VIII hydrogenated active metals, calculated as oxides, is generally 1-8 wt%, preferably 2-6 wt%; and the content of Group VI hydrogenated active metals, calculated as oxides, is generally 2-35 wt%, preferably 4-30 wt%.

[0018] In the preparation method of the catalyst of this invention, the hydrogenation active metal is supported by an impregnation method, in which the hydrogenation active metal is loaded onto a corresponding support. Equal-volume impregnation or excessive impregnation can be used; stepwise impregnation or co-impregnation can 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 VIII active metals. After impregnation, the mixture is allowed to stand for 4–18 hours to air dry, then placed in an oven at 60–120°C for 6–16 hours, and calcined in a muffle furnace at 400–600°C for 4–12 hours to obtain intermediate powder.

[0019] In the preparation method of the catalyst of this invention, Y molecular sieve 1 and Y molecular sieve 2 loaded with hydrogenation active metal, alumina loaded with hydrogenation active metal, and a binder are mixed and kneaded into shape. The binder is usually aluminum sol, soluble boehmite, silica sol, silica-alumina sol, polyethylene glycol, and phosphoalumina sol, etc. The binder is added at 1% to 5% of the weight of the final diesel hydrocracking catalyst. Then, it is dried at 60 to 120°C for 6 to 16 hours and calcined at 400 to 650°C for 2 to 12 hours to obtain the finished catalyst.

[0020] The catalyst of this invention can be in the shape of a toothed ball, a clover, a four-leaf clover, or a cylindrical strip. The diameter of the toothed ball catalyst is 1.4 to 8.0 mm. The length of the clover, four-leaf clover, or cylindrical strip is 1.0 to 12.0 mm, and the diameter is 1.2 to 5.0 mm.

[0021] The diesel hydrocracking catalyst described in this invention is suitable for the hydrocracking process of low-quality diesel fuel. The diesel feedstock typically includes catalytic diesel, coking diesel, fluidized bed diesel, slurry bed diesel, and residue hydrotreated diesel, as well as straight-run diesel. The initial boiling point of the diesel feedstock is between 140 and 260°C, the dry point is between 280 and 390°C, the sulfur content is between 500 and 15000 ppm, and the nitrogen content is between 500 and 1200 ppm.

[0022] In the diesel hydrocracking process, the reaction conditions in the refining reaction zone are generally as follows: reaction pressure 5.0–14.0 MPa, preferably 6.0–10.0 MPa; average reaction temperature 260–420℃, preferably 280–410℃; and refining volume hourly space velocity 0.2–3.0 h⁻¹. -1 Preferably 0.5–2.0 h -1 The reaction conditions within the cracking reaction zone are generally as follows: reaction pressure 5.0–14.0 MPa, preferably 6.0–10.0 MPa; average reaction temperature 300–430 °C, preferably 320–410 °C; cracking volume hourly space velocity 0.5–4.0 h⁻¹. -1 Preferably 1.0 to 3.0 hours -1 .

[0023] Compared with the prior art, the beneficial effects of the method of the present invention are as follows:

[0024] 1. When catalysts with supports of different pore sizes are used, the linear velocity changes dramatically as the reactants pass through particles of different pore sizes within the catalyst. According to Bernoulli's equation, the pressure head on the outer surface of particles with different pore sizes will also differ significantly. The high pressure head of large-pore alumina causes reactants to flow towards the small-pore Y molecular sieve support, thereby significantly improving the diffusion performance of large molecular reactants between catalysts. This achieves the goal of improving the diffusion performance of diesel hydrocracking catalysts for large molecular reactants and reducing the reaction temperature.

[0025] 2. Loading different amounts of active metals onto supports with different pore sizes can effectively reduce the overall active metal loading and packing density of the catalyst, thereby reducing the cost of catalyst raw materials.

[0026] 3. The diesel hydrocracking catalyst of the present invention can process secondary inferior diesel from different sources, with wide adaptability to feedstock, high blending ratio, low reaction temperature, and long operating cycle of the unit. Detailed Implementation

[0027] The preparation method of the diesel hydrocracking catalyst provided by the present invention will be further explained below with reference to the embodiments, but this does not limit the present invention.

[0028] Table 1 Properties of Crude Oil

[0029] Crude oil name diesel fuel <![CDATA[Density (20 °C), g·cm -3 (GB / T 1884)]]> 0.9650 Distillation range, °C (ASTM D1160) Sulfur content, ppm 8000 Nitrogen content, ppm 580 IBP~EBP 150～380 Group composition, wt% (SH / T 0606) Total alkanes 11.5 Total cycloalkanes 20.5 Total aromatics 68.0

[0030] Table 2 Physicochemical properties of refined catalysts and other supports

[0031] Catalysts and supports FHUDS-8 1-Y 2-Y 3-Y <![CDATA[Al2O3]]> Average pore size / nm 5.6 2.5 7.0 9.0 12.0 <![CDATA[Pore volume / mL·g -1 > 0.35 0.25 0.23 0.20 0.42 shape Clover cylindrical bar cylindrical bar cylindrical bar cylindrical bar

[0032] Table 3 Evaluation Criteria

[0033] Reaction pressure, MPa 8.0 <![CDATA[Refining / cracking agent mass hourly space velocity, h -1 > 1.0 / 2.0 Hydrogen-to-oil ratio at the inlet of the hydrorefining / cracking reaction zone, v / v 400:1 / 600:1 Nitrogen content of refined oil, ppm 10 Conversion rate, % 75 Operating time, days 100

[0034] The feedstock used in the following examples and comparative examples is a blend of catalytic diesel and straight-run diesel, the properties of which are shown in Table 1. The refining reactor is loaded with industrial catalyst FHUDS-8, and the properties of FHUDS-8 and the support required for preparing the hydrocracking catalyst by the method of this invention are shown in Table 2. The catalyst evaluation conditions in all examples and comparative examples are the same, as shown in Table 3.

[0035] In this embodiment, catalysts with different properties are used, and their synthesis methods are as follows.

[0036] Example 1

[0037] Two types of Y-zeolite with different average pore sizes were selected as supports: the smallest pore size 1-Y-zeolite support had an average pore size of 2.5 nm, and the largest pore size 2-Y-zeolite support had an average pore size of 7.0 nm.

[0038] Using 1-Y as a carrier, nickel and tungsten 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 8 hours, and finally calcined in a muffle furnace at 500℃ for 8 hours to obtain catalyst-A powder. Based on the mass of the 1-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-A was 1.0 wt%, and the molybdenum active metal loading was 2.0 wt%.

[0039] Using 2-Y as a carrier, nickel and tungsten active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 5 hours to air dry, then dried in an oven at 120℃ for 8 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-B powder. Based on the mass of the 2-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-B was 3.0 wt%, and the molybdenum active metal loading was 10.0 wt%.

[0040] Using alumina as a carrier, nickel and tungsten 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 8 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-C powder. Based on the mass of the alumina supporting the active metals, the nickel active metal loading in catalyst-C was 4.0 wt%, and the molybdenum active metal loading was 18.0 wt%.

[0041] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 2.0 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100℃ for 6 h and calcined at 450℃ for 4 h to obtain catalyst HC-1. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 16.0 wt%, the mass fraction of catalyst-B was 36.0 wt%, and the mass fraction of catalyst-C was 48.0 wt%.

[0042] The refining reactor was filled with FHUDS-8 hydrorefining catalyst, and the HC-1 catalyst synthesized by the above method was loaded into the hydrocracking reaction zone. Diesel fuel in Table 1 was used as feedstock, and the reaction was evaluated according to the conditions in Table 3.

[0043] Example 2

[0044] Two types of Y-zeolite with different average pore sizes were selected as supports: the smallest pore size 1-Y-zeolite support had an average pore size of 2.5 nm, and the largest pore size 3-Y-zeolite support had an average pore size of 9.0 nm.

[0045] Using 1-Y as a carrier, nickel and tungsten active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to dry, then dried in an oven at 120℃ for 8 hours, and finally calcined in a muffle furnace at 550℃ for 8 hours to obtain catalyst-A powder. Based on the mass of the 1-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-A was 2.0 wt%, and the molybdenum active metal loading was 4.0 wt%.

[0046] Using 3-Y as a carrier, nickel and tungsten active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 5 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 mass of the 3-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-B was 3.0 wt%, and the molybdenum active metal loading was 10.0 wt%.

[0047] Using alumina as a carrier, nickel and tungsten 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 8 hours, and finally calcined in a muffle furnace at 550℃ for 6 hours to obtain catalyst-C powder. Based on the mass of the alumina supporting the active metals, the nickel active metal loading in catalyst-C was 4.0 wt%, and the molybdenum active metal loading was 25.0 wt%.

[0048] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 3.0 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100℃ for 4 h and calcined at 450℃ for 6 h to obtain catalyst HC-2. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 14.0 wt%, the mass fraction of catalyst-B was 30.0 wt%, and the mass fraction of catalyst-C was 56.0 wt%.

[0049] The refining reactor was filled with FHUDS-8 hydrorefining catalyst, and the HC-2 catalyst synthesized by the above method was loaded into the hydrocracking reaction zone. Diesel fuel in Table 1 was used as feedstock, and the reaction was evaluated according to the conditions in Table 3.

[0050] Example 3

[0051] Two types of Y-zeolite with different average pore sizes were selected as supports: the smallest pore size 1-Y-zeolite support had an average pore size of 2.5 nm, and the largest pore size 2-Y-zeolite support had an average pore size of 7.0 nm.

[0052] Using 1-Y as a carrier, nickel and tungsten 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 8 hours, and finally calcined in a muffle furnace at 500℃ for 12 hours to obtain catalyst-A powder. Based on the mass of the 1-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-A was 2.5 wt%, and the molybdenum active metal loading was 8.0 wt%.

[0053] Using 2-Y as a carrier, nickel and tungsten active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to dry, then dried in an oven at 100℃ for 8 hours, and finally calcined in a muffle furnace at 550℃ for 8 hours to obtain catalyst-B powder. Based on the mass of the 2-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-B was 4.0 wt%, and the molybdenum active metal loading was 12.0 wt%.

[0054] Using alumina as a carrier, nickel and tungsten active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to dry, then dried in an oven at 100℃ for 8 hours, and finally calcined in a muffle furnace at 550℃ for 8 hours to obtain catalyst-C powder. Based on the mass of the alumina supporting the active metals, the nickel active metal loading in catalyst-C was 4.5 wt%, and the molybdenum active metal loading was 30.5 wt%.

[0055] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 4.0 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 120°C for 6 h and calcined at 450°C for 8 h to obtain catalyst HC-3. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 19.5 wt%, the mass fraction of catalyst-B was 31.0 wt%, and the mass fraction of catalyst-C was 49.5 wt%.

[0056] The refining reactor was filled with FHUDS-8 hydrorefining catalyst, and the HC-3 catalyst synthesized by the above method was loaded into the hydrocracking reaction zone. Diesel fuel in Table 1 was used as feedstock, and the reaction was evaluated according to the conditions in Table 3.

[0057] Example 4

[0058] Two types of Y-zeolite with different average pore sizes were selected as supports: the smallest pore size 1-Y-zeolite support had an average pore size of 2.5 nm, and the largest pore size 3-Y-zeolite support had an average pore size of 9.0 nm.

[0059] Using 1-Y as a carrier, nickel and tungsten active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 8 hours to dry, then dried in an oven at 120℃ for 8 hours, and finally calcined in a muffle furnace at 550℃ for 8 hours to obtain catalyst-A powder. Based on the mass of the 1-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-A was 3.0 wt%, and the molybdenum active metal loading was 7.0 wt%.

[0060] Using 3-Y as a carrier, nickel and tungsten active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 5 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 mass of the 3-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-B was 4.0 wt%, and the molybdenum active metal loading was 12.0 wt%.

[0061] Using alumina as a carrier, nickel and tungsten active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 6 hours to dry, then dried in an oven at 100℃ for 8 hours, and finally calcined in a muffle furnace at 550℃ for 6 hours to obtain catalyst-C powder. Based on the mass of the alumina supporting the active metals, the nickel active metal loading in catalyst-C was 4.0 wt%, and the molybdenum active metal loading was 30.0 wt%.

[0062] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 3.0 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100℃ for 6 h and calcined at 550℃ for 6 h to obtain catalyst HC-4. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 11.0 wt%, the mass fraction of catalyst-B was 29.0 wt%, and the mass fraction of catalyst-C was 60.0 wt%.

[0063] The refining reactor was filled with FHUDS-8 hydrorefining catalyst, and the HC-4 catalyst synthesized by the above method was loaded into the hydrocracking reaction zone. Diesel fuel in Table 1 was used as feedstock, and the reaction was evaluated according to the conditions in Table 3.

[0064] Comparative Example 1

[0065] Using 1-Y as a carrier, nickel and tungsten 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 8 hours, and finally calcined in a muffle furnace at 500℃ for 8 hours to obtain catalyst-A powder. Based on the mass of the 1-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-A was 1.0 wt%, and the molybdenum active metal loading was 2.0 wt%.

[0066] Using 1-Y as a carrier, nickel and tungsten active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 5 hours to air dry, then dried in an oven at 120℃ for 8 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-B powder. Based on the mass of the 1-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-B was 3.0 wt%, and the molybdenum active metal loading was 10.0 wt%.

[0067] Using alumina as a carrier, nickel and tungsten 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 8 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-C powder. Based on the mass of the alumina supporting the active metals, the nickel active metal loading in catalyst-C was 4.0 wt%, and the molybdenum active metal loading was 18.0 wt%.

[0068] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 2.0 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100℃ for 6 h and calcined at 450℃ for 4 h to obtain catalyst HC-5. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 16.0 wt%, the mass fraction of catalyst-B was 36.0 wt%, and the mass fraction of catalyst-C was 48.0 wt%.

[0069] The refining reactor was filled with FHUDS-8 hydrorefining catalyst, and the HC-5 catalyst synthesized by the above method was loaded into the hydrocracking reaction zone. Diesel fuel in Table 1 was used as feedstock, and the reaction was evaluated according to the conditions in Table 3.

[0070] Comparative Example 2

[0071] Using 2-Y as a carrier, nickel and tungsten 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 8 hours, and finally calcined in a muffle furnace at 500℃ for 8 hours to obtain catalyst-A powder. Based on the mass of the 1-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-A was 1.0 wt%, and the molybdenum active metal loading was 2.0 wt%.

[0072] Using 2-Y as a carrier, nickel and tungsten active metals were impregnated separately using an equal-volume impregnation method. After impregnation, the active metals were allowed to stand for 5 hours to air dry, then dried in an oven at 120℃ for 8 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-B powder. Based on the mass of the 2-Y molecular sieve supporting the active metal, the nickel active metal loading in catalyst-B was 3.0 wt%, and the molybdenum active metal loading was 10.0 wt%.

[0073] Using alumina as a carrier, nickel and tungsten 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 8 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-C powder. Based on the mass of the alumina supporting the active metals, the nickel active metal loading in catalyst-C was 4.0 wt%, and the molybdenum active metal loading was 18.0 wt%.

[0074] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 2.0 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100℃ for 6 h and calcined at 450℃ for 4 h to obtain catalyst HC-6. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 16.0 wt%, the mass fraction of catalyst-B was 36.0 wt%, and the mass fraction of catalyst-C was 48.0 wt%.

[0075] The refining reactor was filled with FHUDS-8 hydrorefining catalyst, and the HC-6 catalyst synthesized by the above method was loaded into the hydrocracking reaction zone. Diesel fuel in Table 1 was used as feedstock, and the reaction was evaluated according to the conditions in Table 3.

[0076] Comparative Example 3

[0077] Using 1-Y and 2-Y with equal mass fractions as carriers, nickel and tungsten active metals were impregnated respectively 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 8 hours, and finally calcined in a muffle furnace at 500℃ for 8 hours to obtain catalyst-A powder. Based on the mass of the supported active metal Y molecular sieve, the nickel active metal loading in catalyst-A was 3.0 wt%, and the molybdenum active metal loading was 6.0 wt%.

[0078] Using alumina as a carrier, nickel and tungsten 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 8 hours, and finally calcined in a muffle furnace at 500℃ for 6 hours to obtain catalyst-B powder. Based on the mass of the supported active metal Y molecular sieve, the nickel active metal loading in catalyst-B was 2.0 wt%, and the molybdenum active metal loading was 10.0 wt%.

[0079] The catalyst-A powder and catalyst-B powder prepared above were mechanically mixed, and then 2.0 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100℃ for 6 h and calcined at 450℃ for 4 h to obtain catalyst HC-7. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 40.0 wt%, and the mass fraction of catalyst-B was 60.0 wt%.

[0080] The refining reactor was filled with FHUDS-8 hydrorefining catalyst, and the HC-7 catalyst synthesized by the above method was loaded into the hydrocracking reaction zone. Diesel fuel in Table 1 was used as feedstock, and the reaction was evaluated according to the conditions in Table 3.

[0081] Table 4 Results of the experiments in the examples and comparative examples

[0082]

[0083] 1The conversion rate is uniformly controlled at 75%; 2 Catalyst deactivation rate = (cracking reaction temperature after 100 days of operation - initial reaction temperature) / 100.

[0084] The results of all examples and comparative experiments are shown in Table 4. The experimental results show that, under the same reaction conditions, the diesel cracking catalyst of this patent exhibits lower hydrocracking reaction temperature and lower catalyst deactivation rate in the examples, indicating that the hydrocracking catalyst of this patent has better reactivity and stability.

Claims

1. A method for preparing a diesel hydrocracking catalyst, characterized in that: The final hydrocracking catalyst is prepared by mixing and molding Y molecular sieve 1 supported on hydrogenated active metal, Y molecular sieve 2 supported on hydrogenated active metal, and alumina supported on hydrogenated active metal. The pore size of Y molecular sieve 1 is smaller than that of Y molecular sieve 2, and the pore size of alumina is larger than the average pore size of Y molecular sieve 2. The average pore size is based on the support without hydrogenated active metal. The average pore size of Y molecular sieve 1 is 1-7 nm lower than that of Y molecular sieve 2. The average pore size of the alumina is 2-10 nm higher than that of Y molecular sieve 2; The weight content of hydrogenated active metal (calculated as oxide) of Y molecular sieve 1 loaded with hydrogenated active metal is lower than that of Y molecular sieve 2 loaded with hydrogenated active metal (calculated as oxide) by weight, with a difference of 5-35 wt%. The weight content of hydrogenated active metal in Y molecular sieve 2, based on its weight, is lower than that of hydrogenated active metal in alumina, based on its weight, by 5 to 40 wt%.

2. The method according to claim 1, characterized in that: The average pore size of Y molecular sieve 1 is 2-6 nm lower than that of Y molecular sieve 2.

3. The method according to claim 2, characterized in that: The average pore size of Y molecular sieve 1 is 3-5 nm lower than that of Y molecular sieve 2.

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

5. The method according to claim 4, characterized in that: The average pore size of the alumina is 4-6 nm larger than that of Y molecular sieve 2.

6. The method according to claim 1, characterized in that: The average pore size of the Y molecular sieve 1 is 1~5 nm; the average pore size of the Y molecular sieve 2 is 3~10 nm; and the average pore size of the alumina is 6~20 nm.

7. The method according to claim 6, characterized in that: The average pore size of the Y molecular sieve 1 is 2~4 nm; the average pore size of the Y molecular sieve 2 is 4~8 nm; and the average pore size of the alumina is 8~16 nm.

8. The method according to claim 1, characterized in that: The weight content of hydrogenated active metal in Y molecular sieve 1, based on its weight, is lower than that in Y molecular sieve 2, based on its weight, by 10~30 wt%.

9. The method according to claim 8, characterized in that: The weight content of hydrogenated active metal in Y molecular sieve 1, based on its weight, is lower than that in Y molecular sieve 2, based on its weight, by 15~25 wt%.

10. The method according to claim 1, characterized in that: The weight content of hydrogenated active metal in Y molecular sieve 2, based on its weight, is lower than that of hydrogenated active metal in alumina, based on its weight, by 8 to 36 wt%.

11. The method according to claim 10, characterized in that: The weight content of hydrogenated active metal in Y molecular sieve 2, based on its weight, is lower than that of hydrogenated active metal in alumina, based on its weight, by 10~30 wt%.

12. The method according to claim 1, characterized in that: Y molecular sieve 1 supported on hydrogenation active metal accounts for 3-20 wt% of the total weight of the final hydrocracking catalyst; Y molecular sieve 2 supported on hydrogenation active metal accounts for 10-40 wt% of the total weight of the final hydrocracking catalyst; alumina supported on hydrogenation active metal accounts for 20-65 wt% of the total weight of the final hydrocracking catalyst; the mass of the hydrocracking catalyst is 100%.

13. The method according to claim 12, characterized in that: Y molecular sieve 1, supported on hydrogenation active metal, accounts for 5-18 wt% of the total weight of the final hydrocracking catalyst; Y molecular sieve 2, supported on hydrogenation active metal, accounts for 12-35 wt% of the total weight of the final hydrocracking catalyst; and alumina, supported on hydrogenation active metal, accounts for 25-55 wt% of the total weight of the final hydrocracking catalyst.

14. The method according to claim 1, characterized in that: Hydrogen-active metals include one or more of Group VIB, Group VIIB, Group VIII metals or their metal oxides or metal sulfides.

15. The method according to claim 14, characterized in that: The active metal for hydrogenation is one or more of iron, chromium, molybdenum, tungsten, cobalt, nickel, or their sulfides or oxides.

16. The method according to claim 14, characterized in that: Based on the total weight of Y molecular sieve 1 loaded with hydrogenated active metal, the content of hydrogenated active metal in Y molecular sieve 1, calculated as oxide, is 2-15 wt%; among which, the content of Group VIIB or Group VIII hydrogenated active metal oxide is 0-5 wt%, and the content of Group VIB hydrogenated active metal, calculated as oxide, is 0-10 wt%.

17. The method according to claim 16, characterized in that: Based on the total weight of Y molecular sieve 1 loaded with hydrogenated active metal, the content of hydrogenated active metal in Y molecular sieve 1, calculated as oxide, is 2-12 wt%; among which, the content of Group VIIB or Group VIII hydrogenated active metal oxide is 1-4 wt%, and the content of Group VIB hydrogenated active metal, calculated as oxide, is 2-8 wt%.

18. The method according to claim 14, characterized in that: Based on the total weight of Y molecular sieve 2 loaded with hydrogenated active metal, the content of hydrogenated active metal in Y molecular sieve 2 as oxide is 2-30 wt%; among which, the content of Group VIIB or Group VIII hydrogenated active metal as oxide is 1-8 wt%; and the content of Group VIB hydrogenated active metal as oxide is 1-25 wt%.

19. The method according to claim 18, characterized in that: Based on the total weight of Y molecular sieve 2 loaded with hydrogenated active metal, the content of hydrogenated active metal in Y molecular sieve 2 as oxide is 5-26 wt%; among which, the content of Group VIIB or Group VIII hydrogenated active metal as oxide is 2-6 wt%; and the content of Group VIB hydrogenated active metal as oxide is 3-22 wt%.

20. The method according to claim 14, characterized in that: Based on the total weight of the alumina loaded with hydrogenated active metals, the content of hydrogenated active metals in the alumina loaded with hydrogenated active metals, calculated as oxides, is 3–42 wt%; of which the content of Group VIIB or Group VIII hydrogenated active metals, calculated as oxides, is 1–8 wt%; and the content of Group VIB hydrogenated active metals, calculated as oxides, is 2–35 wt%.

21. The method according to claim 20, characterized in that: Based on the total weight of the alumina loaded with hydrogenated active metals, the content of hydrogenated active metals in the alumina loaded with hydrogenated active metals, calculated as oxides, is 8–35 wt%; of which the content of Group VIIB or Group VIII hydrogenated active metals, calculated as oxides, is 2–6 wt%; and the content of Group VIB hydrogenated active metals, calculated as oxides, is 4–30 wt%.

22. The method according to claim 1, characterized in that: Y molecular sieve 1 and Y molecular sieve 2 loaded with hydrogenated active metal, alumina loaded with hydrogenated active metal, and binder are mixed and kneaded into shape.

23. The diesel hydrocracking catalyst prepared by any one of claims 1-22.

24. The diesel hydrocracking catalyst prepared according to any one of claims 1-22 is used in the hydrocracking process of inferior diesel.

25. The hydrocracking process according to claim 24, characterized in that: Inferior diesel fuel includes catalytic diesel fuel and coking diesel fuel. The initial boiling point of inferior diesel fuel is between 140 and 260°C, the dry point is between 280 and 390°C, the sulfur content is between 500 and 15,000 ppm, and the nitrogen content is between 500 and 1,200 ppm.

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