A method for preparing a diesel hydrodewaxing catalyst

Abstract

This invention provides a method for preparing a diesel hydrodewaxing catalyst. The catalyst contains ZSM-5 molecular sieve and alumina, wherein the average pore size of the alumina is higher than that of the ZSM-5 molecular sieve, generally 2-15 nm higher, preferably 4-10 nm. The method for preparing the catalyst includes the following steps: (1) Selecting or preparing ZSM-5 molecular sieve 1 and introducing a hydrogenation active metal into ZSM-5 molecular sieve 1; (2) Selecting or preparing ZSM-5 molecular sieve 2 and introducing a hydrogenation active metal into ZSM-5 molecular sieve 2; optionally, (3) Selecting or preparing alumina and introducing a hydrogenation active metal into alumina; (4) Mixing and molding the materials obtained in steps (1), (2) and (3) to obtain the final diesel hydrodewaxing catalyst. The catalyst can reduce the reaction temperature and extend the operating cycle of the device.

Description

Technical Field

[0001] This invention relates to a diesel hydrocracking catalyst, its preparation method, and its application, specifically to a catalyst for producing low-pour-point diesel through diesel hydrocracking, its preparation method, and its application. Background Technology

[0002] Hydrogenation dewaxing, also known as catalytic dewaxing, is a new refining process developed in the 1970s. In the presence of hydrogen, a molecular sieve catalyst produces low-pour-point diesel oil from distillate oils (such as paraffin-based feedstocks) and also yields high-octane gasoline and liquefied petroleum gas (LPG). This process is simple, operates under mild conditions, offers flexible product options, and consumes very little hydrogen. Since its industrial application in 1974, more than 40 industrial plants have been put into operation domestically and internationally, with a total processing capacity of 11 million tons per year. The key to diesel hydrodewaxing technology is the use of a ZSM-5 molecular sieve catalyst with shape-selective cracking capabilities. The size of the straight and corrugated pores in the molecular sieve pore system is between 0.51 and 0.56 nm. n-alkanes and isoalkanes with methyl branches can enter the pores of the ZSM-5 molecular sieve and crack into low-molecular-weight hydrocarbons, while aromatics, cycloalkanes, and highly isoalkanes cannot enter the pores of the ZSM-5 molecular sieve and remain unchanged. By selectively removing n-alkanes from the oil, the pour point of the diesel oil can be lowered.

[0003] However, conventional diesel hydrodewaxing catalysts suffer from the problem of large-molecule alkanes having difficulty entering the molecular channels, resulting in short catalyst lifespans and high cracking temperatures. Only by developing catalysts with strong cracking capabilities for large-molecule alkanes can the long-cycle technical requirements of industrial production be met.

[0004] There are numerous reports on methods for preparing hydrodewaxing catalysts for diesel fuel, but few on improving the activity of these catalysts and extending the operating cycle of the equipment. CN112725022B discloses a hydrodewaxing method in which paraffinic diesel feedstock is passed through a series of hydrorefining and hydrodewaxing reaction zones, followed by separation to obtain a low-pour-point diesel product. The hydrodewaxing reaction zone is filled with a dewaxing catalyst containing ZSM-5 molecular sieves. The dewaxing catalyst has a cracking rate of less than 2% for 1,3,5-triisopropylbenzene. The dewaxing catalyst is prepared by treating its outer surface to reduce or remove acidic sites. This catalyst primarily aims to reduce the cracking rate and the pour point of diesel fuel, but it cannot fundamentally solve the problem of poor activity in diesel hydrodewaxing catalysts.

[0005] CN112536062A discloses a hydrogenation dewaxing catalyst, its preparation method, and its application. The method prepares a catalyst containing an active metal oxide and a support. The catalyst support comprises a catalyst support with a porous surface and a molecular sieve membrane located on the surface of the pores of the support. The porous catalyst support contains alumina and a metal oxide promoter, wherein the alumina and metal oxide promoter form a spinel structure. While this catalyst exhibits excellent hydrogenation activity and selectivity, the molecular sieve membrane is costly to prepare, metal loading is difficult, the active sites have low accessibility, and stability is poor.

[0006] CN114479924A discloses a method for hydrodewaxing. The feedstock oil passes through a hydrorefining reaction zone and a hydrodewaxing reaction zone, followed by separation to obtain low-pour-point diesel product. The ZSM-5 molecular sieve contained in the hydrodewaxing catalyst packed in the hydrodewaxing reaction zone exhibits an increasing trend in total acid content and a decreasing trend in the proportion of non-framework aluminum along the feed direction. This method can improve the quality of diesel product and obtain low-pour-point diesel in high yield, but it cannot solve the problem of poor activity and stability of the hydrodewaxing catalyst. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a diesel hydroponic dewaxing catalyst, its preparation method, and its application. The catalyst can reduce reaction temperature and extend the operating cycle of the equipment.

[0008] A diesel hydrodewaxing catalyst, the catalyst containing ZSM-5 molecular sieve and alumina, wherein the average pore size of the alumina is higher than the average pore size of the ZSM-5 molecular sieve, the average pore size being based on a support without active metal loading.

[0009] In the catalyst of this invention, the pore size of the alumina is higher than that of the ZSM-5 molecular sieve, generally 2 to 15 nm higher, preferably 4 to 10 nm.

[0010] In the catalyst of the present invention, the diesel hydrodewaxing catalyst contains a hydrogenation active component, which 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.

[0011] In the catalyst of this invention, based on the total weight of the diesel hydrodewaxing catalyst, the content of the hydroadding active component, calculated as metal oxide, is typically 5–35 wt%, preferably 6–25 wt%; wherein the content of Group VII or Group VIII hydroadding active metal oxides is typically 2–8 wt%, preferably 3–6 wt%; and the content of Group VI hydroadding active metal oxides is typically 3–30 wt%, preferably 5–28 wt%.

[0012] In the catalyst of this invention, the alumina supported on the active metal accounts for 20-60 wt%, preferably 25-50 wt%, of the total weight of the final hydrodewaxing catalyst. Based on the weight of the alumina supported on the active metal, the mass content of the hydrogenation active metal, calculated as an oxide, is typically 4-25 wt%, preferably 8-20 wt%; wherein the mass content of Group VII or Group VIII hydrogenation active metal oxides is typically 1-8 wt%, preferably 2-6 wt%; and the mass content of Group VI hydrogenation active metal oxides is typically 3-25 wt%, preferably 4-20 wt%.

[0013] The catalyst of this invention contains two types of ZSM-5 molecular sieves, referred to as ZSM-5 molecular sieve 1 and ZSM-5 molecular sieve 2, wherein the average pore size of ZSM-5 molecular sieve 1 is lower than that of ZSM-5 molecular sieve 2.

[0014] In the catalyst of the present invention, the average pore size of the ZSM-5 molecular sieve 1 is 2 to 10 nm lower than that of the ZSM-5 molecular sieve 2, preferably 3 to 8 nm, and more preferably 4 to 6 nm.

[0015] In the catalyst of the present invention, the average pore size of the ZSM-5 molecular sieve 1 is 1-4 nm, and the average pore size of the ZSM-5 molecular sieve 2 is 4-12 nm.

[0016] In the catalyst of this invention, the weight percentage of the hydrogenated active metal supported in ZSM-5 molecular sieve 1, calculated as hydrogenated active metal oxide, is lower than the weight percentage of the hydrogenated active metal supported in ZSM-5 molecular sieve 2, calculated as hydrogenated active metal oxide. The weight basis is calculated based on ZSM-5 molecular sieve 1 and ZSM-5 molecular sieve 2, respectively, which are loaded with hydrogenated active metal.

[0017] In the catalyst of the present invention, the weight percentage of the hydrogenated active metal supported in ZSM-5 molecular sieve 1 (based on hydrogenated active metal oxide) is 3 to 25 wt%, preferably 5 to 20 wt%, and more preferably 6 to 18 wt%, compared with the weight percentage of the hydrogenated active metal supported in ZSM-5 molecular sieve 2 (based on hydrogenated active metal oxide). The weight basis is based on ZSM-5 molecular sieve 1 and ZSM-5 molecular sieve 2 supported on hydrogenated active metal, respectively.

[0018] In the catalyst of this invention, the ZSM-5 molecular sieve 1 supported with hydrogenated active metals has a mass content of 0-6 wt%, preferably 1-5 wt%, based on the weight of the ZSM-5 molecular sieve 1 supported with hydrogenated active metals; wherein the mass content of Group VII or Group VIII hydrogenated active metal oxides is typically 0-2 wt%, preferably 0.5-1.5 wt%, and the mass content of Group VI hydrogenated active metal oxides is typically 0-4 wt%, preferably 1-3 wt%.

[0019] In the catalyst of this invention, the ZSM-5 molecular sieve 2 supported with hydrogenated active metals typically contains 3–30 wt% hydrogenated active metal oxides, preferably 5–25 wt%, based on the weight of the ZSM-5 molecular sieve 2. Specifically, the mass content of Group VII or Group VIII hydrogenated active metal oxides is typically 1–6 wt%, preferably 2–5 wt%, and the mass content of Group VI hydrogenated active metal oxides is typically 2–24 wt%, preferably 4–20 wt%.

[0020] In the catalyst of this invention, the ZSM-5 molecular sieve 1 supported on hydrogenated active metal accounts for 2 to 20 wt% of the total weight of the final diesel hydrodewaxing catalyst, preferably 4 to 16 wt%.

[0021] In the catalyst of this invention, the ZSM-5 molecular sieve 2 supported on hydrogenation active metal accounts for 5 to 30 wt% of the total weight of the final hydrodewaxing catalyst, preferably 8 to 25 wt%.

[0022] The preparation method of the above-mentioned diesel hydroponic dewaxing catalyst includes the following steps.

[0023] (1) Select or prepare ZSM-5 molecular sieve 1, and introduce hydrogenated active metal into ZSM-5 molecular sieve 1;

[0024] (2) Select or prepare ZSM-5 molecular sieve 2, and introduce hydrogenated active metal into ZSM-5 molecular sieve 2;

[0025] Optional, (3) Select or prepare alumina, and introduce a hydrogenated active metal into the alumina;

[0026] (4) The materials obtained in steps (1), (2) and (3) are mixed and molded to obtain the final diesel hydrodewaxing catalyst.

[0027] In the method of this invention, the hydrogenated active metal is introduced in steps (1) and / or (2) and / or (3) by impregnation, which involves loading the hydrogenated active metal onto a corresponding support. This impregnation can be done using equal volume impregnation or excessive impregnation; it can be done stepwise impregnation or co-impregnation, 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 mixture is allowed to stand for 2–20 hours to air dry, then placed in an oven at 50–160°C for 4–120 hours, and calcined in a muffle furnace at 350–650°C for 2–18 hours to obtain intermediate powder.

[0028] In the method of this invention, the materials obtained in steps (1), (2), and (3) are mixed with a binder and then kneaded into shape. The binder is typically aluminum sol, soluble boehmite, silica sol, silica-alumina sol, polyethylene glycol, and phosphoalumina sol, etc., and its mass fraction relative to the dry-based catalyst is 3% to 8%. After molding, the catalyst is dried at 80 to 140°C for 4 to 20 hours and then calcined at 350 to 650°C for 2 to 12 hours to obtain the finished catalyst product.

[0029] 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 1.5 to 10.0 mm. The length of the clover, four-leaf clover, or cylindrical strip is 1.4 to 10.0 mm, and the diameter is 1.0 to 6.0 mm.

[0030] The diesel hydrodewaxing catalyst described in this invention is suitable for use in diesel hydrodewaxing processes, where the diesel feedstock is generally straight-run diesel or coking diesel. The initial boiling point of the diesel feedstock is between 150 and 240°C, the dry point is between 270 and 380°C, the sulfur content is between 200 and 12000 ppm, and the nitrogen content is between 200 and 1000 ppm.

[0031] In the process of hydrodewaxing diesel fuel, the reaction conditions in the refining reaction zone are generally as follows: reaction pressure 4.0–12.0 MPa, preferably 5.0–8.0 MPa; average reaction temperature 270–410℃, preferably 300–400℃; and refining volume hourly space velocity 0.1–4.0 h⁻¹. -1 Preferably 0.5 to 1.5 hours -1 The reaction conditions within the cracking reaction zone are generally as follows: reaction pressure 4.0–12.0 MPa, preferably 5.0–8.0 MPa; average reaction temperature 310–420 °C, preferably 320–400 °C; cracking volume hourly space velocity 0.2–3.0 h⁻¹. -1 Preferably 0.5–2.0 h -1 .

[0032] This invention discloses a method for preparing a diesel hydrocracking catalyst, which can be used in any diesel hydrocracking field. It is particularly suitable for producing low-pour-point diesel products by hydrocracking of inferior diesel.

[0033] Compared with the prior art, the beneficial effects of the diesel hydrodewaxing catalyst of the present invention are as follows:

[0034] 1. By using ZSM-5 molecular sieves with different pore sizes, the pressure head changes after the reactant flows through the ZSM-5 molecular sieve. The pressure head of the large-pore ZSM-5 molecular sieve is high, and the reactants will flow to the small-pore ZSM-5 molecular sieve support, thereby significantly improving the external diffusion performance of large molecular chain alkanes between catalysts and achieving the purpose of improving the activity of diesel hydrodewaxing catalyst.

[0035] 2. By loading different amounts of active metals onto supports with different pore sizes, the overall metal loading and packing density of the catalyst can be effectively reduced, thereby lowering the cost of catalyst raw materials.

[0036] 3. The diesel hydrodewaxing catalyst of the present invention can process paraffinic diesel with a higher dry point, has strong adaptability to feedstock, low reaction temperature, and long operating cycle of the equipment. Detailed Implementation

[0037] The preparation method of the diesel hydrodewaxing catalyst provided by the present invention will be further explained below with reference to the embodiments, but this does not limit the present invention.

[0038] Table 1 Properties of Crude Oil

[0039] Crude oil name diesel fuel <![CDATA[Density (20 °C), g·cm -3 (GB / T 1884)]]> 0.8050 Distillation range, °C (ASTM D1160) IBP~EBP 160～375 Sulfur content, ppm 5000 Nitrogen content, ppm 350 Group composition, wt% (SH / T 0606) Total alkanes 51.5 Total cycloalkanes 20.5 Total aromatics 28.0

[0040] Table 2 Physicochemical properties of catalysts and supports

[0041] Catalysts and supports FF-66 1-ZSM-5 2-ZSM-5 3-ZSM-5 <![CDATA[Al2O3]]> Average pore size / nm 6.5 3.0 8.0 10.0 14.0 <![CDATA[Pore volume / mL·g -1 > 0.40 0.20 0.25 0.27 0.45 shape Clover cylindrical bar cylindrical bar cylindrical bar cylindrical bar

[0042] Table 3 Evaluation Criteria

[0043] Reaction pressure, MPa 10.0 <![CDATA[Refining / Cracking Agent Mass Space Velocity, h -1 > 1.0 / 1.5 Hydrogen-to-oil ratio at the inlet of the hydrorefining / cracking reaction zone, v / v 200:1 / 400:1 Nitrogen content of refined oil, ppm 10 Diesel pour point, ℃ -20 Operating time, days 100

[0044] The feedstock used in the following examples and comparative examples is straight-run diesel oil, the properties of which are shown in Table 1. The refining reactor is loaded with industrial catalyst FF-66, and the properties of the support required for preparing the hydrodewaxing 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.

[0045] In this embodiment, catalysts with different properties are used, and their synthesis methods are as follows.

[0046] Example 1

[0047] Two ZSM-5 molecular sieves with different average pore sizes were selected as supports: the smallest pore size 1 - the average pore size of the ZSM-5 molecular sieve support was 3.0 nm, and the largest pore size 2 - the average pore size of the ZSM-5 support was 8.0 nm.

[0048] Using 1-ZSM-5 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 6 hours, and finally calcined at 500℃ for 8 hours to obtain catalyst-A powder. Based on the mass of the supported active metal 1-ZSM-5, the nickel active metal loading in catalyst-A was 1.5 wt%, and the molybdenum active metal loading was 2.5 wt%.

[0049] Using 2-ZSM-5 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 as powder. Based on the mass of the 2-ZSM-5 carrier, the nickel active metal loading in catalyst-B was 3.0 wt%, and the molybdenum active metal loading was 15 wt%.

[0050] 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 as 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%.

[0051] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 2.5 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100°C for 6 h and calcined at 450°C for 6 h to obtain catalyst C-1. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 14 wt%, the mass fraction of catalyst-B was 29 wt%, and the mass fraction of catalyst-C was 57 wt%.

[0052] The refining reactor was filled with FF-66 hydrorefining catalyst, and the C-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.

[0053] Example 2

[0054] Two ZSM-5 molecular sieves with different average pore sizes were selected as supports: the smallest pore size 1 - the average pore size of the ZSM-5 molecular sieve support was 3.0 nm, and the largest pore size 2 - the average pore size of the ZSM-5 support was 8.0 nm.

[0055] Using 1-ZSM-5 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 6 hours, and finally calcined at 550℃ for 8 hours to obtain catalyst-A as a powder. Based on the mass of the supported active metal 1-ZSM-5, the nickel active metal loading in catalyst-A was 1.0 wt%, and the molybdenum active metal loading was 3.0 wt%.

[0056] Using 2-ZSM-5 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 as powder. Based on the mass of the 2-ZSM-5 carrier active metal, the nickel active metal loading in catalyst-B was 3.0 wt%, and the molybdenum active metal loading was 12.0 wt%.

[0057] 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 as 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 22.5 wt%.

[0058] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 2.5 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100°C for 6 h and calcined at 450°C for 6 h to obtain catalyst C-2. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 19 wt%, the mass fraction of catalyst-B was 24 wt%, and the mass fraction of catalyst-C was 57 wt%.

[0059] The refining reactor was filled with FF-66 hydrorefining catalyst, and the C-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.

[0060] Example 3

[0061] Two ZSM-5 molecular sieves with different average pore sizes were selected as supports: the smallest pore size 1 - the average pore size of the ZSM-5 molecular sieve support was 3.0 nm, and the largest pore size 3 - the average pore size of the ZSM-5 support was 10.0 nm.

[0062] Using 1-ZSM-5 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 6 hours, and finally calcined at 450℃ for 8 hours to obtain catalyst-A as a powder. Based on the mass of the supported active metal 1-ZSM-5, the nickel active metal loading in catalyst-A was 1.5 wt%, and the molybdenum active metal loading was 3.0 wt%.

[0063] Using 3-ZSM-5 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 450℃ for 6 hours to obtain catalyst-B as powder. Based on the mass of the 3-ZSM-5 supporting active metal, the nickel active metal loading in catalyst-B was 2.0 wt%, and the molybdenum active metal loading was 12.5 wt%.

[0064] 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 450℃ for 6 hours to obtain catalyst-C as 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 22.0 wt%.

[0065] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 2.5 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100°C for 6 h and calcined at 450°C for 6 h to obtain catalyst C-3. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 14.5 wt%, the mass fraction of catalyst-B was 28.5 wt%, and the mass fraction of catalyst-C was 57 wt%.

[0066] The refining reactor was filled with FF-66 hydrorefining catalyst, and the C-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.

[0067] Example 4

[0068] Two ZSM-5 molecular sieves with different average pore sizes were selected as supports: the smallest pore size 1 - the average pore size of the ZSM-5 molecular sieve support was 3.0 nm, and the largest pore size 3 - the average pore size of the ZSM-5 support was 10.0 nm.

[0069] Using 1-ZSM-5 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 6 hours, and finally calcined at 600℃ for 8 hours to obtain catalyst-A as a powder. Based on the mass of the supported active metal 1-ZSM-5, the nickel active metal loading in catalyst-A was 1.0 wt%, and the molybdenum active metal loading was 3.0 wt%.

[0070] Using 3-ZSM-5 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 600℃ for 6 hours to obtain catalyst-B as powder. Based on the mass of the 3-ZSM-5 supporting active metal, the nickel active metal loading in catalyst-B was 3.0 wt%, and the molybdenum active metal loading was 11.5 wt%.

[0071] 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 600℃ for 6 hours to obtain catalyst-C as 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 21.5 wt%.

[0072] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 2.5 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100°C for 6 hours and calcined at 550°C for 6 hours to obtain catalyst C-4. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 12 wt%, the mass fraction of catalyst-B was 28.5 wt%, and the mass fraction of catalyst-C was 59.5 wt%.

[0073] The refining reactor was filled with FF-66 hydrorefining catalyst, and the C-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.

[0074] Comparative Example 1

[0075] Using 1-ZSM-5 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 6 hours, and finally calcined at 500℃ for 8 hours to obtain catalyst-A powder. Based on the mass of the supported active metal 1-ZSM-5, the nickel active metal loading in catalyst-A was 1.5 wt%, and the molybdenum active metal loading was 2.5 wt%.

[0076] Using 1-ZSM-5 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 as powder. Based on the mass of the supported active metal 1-ZSM-5, the nickel active metal loading in catalyst-B was 3.0 wt%, and the molybdenum active metal loading was 15 wt%.

[0077] 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 as 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%.

[0078] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 2.5 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100°C for 6 h and calcined at 450°C for 6 h to obtain catalyst C-5. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 14 wt%, the mass fraction of catalyst-B was 29 wt%, and the mass fraction of catalyst-C was 57 wt%.

[0079] The refining reactor was filled with FF-66 hydrorefining catalyst, and the C-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.

[0080] Comparative Example 2

[0081] Using 2-ZSM-5 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 6 hours, and finally calcined at 550℃ for 8 hours to obtain catalyst-A as a powder. Based on the mass of the 2-ZSM-5 supporting active metal, the nickel active metal loading in catalyst-A was 1.0 wt%, and the molybdenum active metal loading was 3.0 wt%.

[0082] Using 2-ZSM-5 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 as powder. Based on the mass of the 2-ZSM-5 carrier active metal, the nickel active metal loading in catalyst-B was 3.0 wt%, and the molybdenum active metal loading was 12.0 wt%.

[0083] 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 as 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 22.5 wt%.

[0084] The catalyst-A powder, catalyst-B powder, and catalyst-C powder prepared above were mechanically mixed, and then 2.5 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100°C for 6 h and calcined at 450°C for 6 h to obtain catalyst C-6. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 19 wt%, the mass fraction of catalyst-B was 24 wt%, and the mass fraction of catalyst-C was 57 wt%.

[0085] The refining reactor was filled with FF-66 hydrorefining catalyst, and the C-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.

[0086] Comparative Example 3

[0087] Using 1-ZSM-5 and 2-ZSM-5 with equal mass fractions as carriers, 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 6 hours, and finally calcined at 550℃ for 8 hours to obtain catalyst-A as powder. Based on the total mass of all ZSM-5 supporting the active metals, the nickel active metal loading in catalyst-A was 3.0 wt%, and the molybdenum active metal loading was 10.0 wt%.

[0088] 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 as powder. Based on the mass of the alumina supporting the active metals, the nickel active metal loading in catalyst-C was 6 wt%, and the molybdenum active metal loading was 25 wt%.

[0089] The catalyst-A powder and catalyst-B powder prepared above were mechanically mixed, and then 2.5 wt% polyethylene glycol binder was added and extruded. The mixture was then dried at 100°C for 6 h and calcined at 450°C for 6 h to obtain catalyst C-7. Based on the total weight of the catalysts, the mass fraction of catalyst-A was 40 wt% and the mass fraction of catalyst-B was 60 wt%.

[0090] The refining reactor was filled with FF-66 hydrorefining catalyst, and the C-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.

[0091] Table 4 Results of the experiments in the examples and comparative examples

[0092]

[0093] 1. The pour point of diesel products is uniformly controlled at -20℃; 2. Catalyst deactivation rate = (cracking reaction temperature after 100 days of operation - initial reaction temperature) / 100.

[0094] The test results of all embodiments and comparative examples are shown in Table 4. The test results of the embodiments and comparative examples show that the diesel cracking catalyst of this patent invention exhibits lower hydrocracking reaction temperature and catalyst deactivation rate, indicating that the hydrocracking catalyst of this patent invention has better reaction activity and stability.

Claims

1. A diesel fuel hydrodewaxing catalyst, characterized in that: The catalyst contains ZSM-5 molecular sieve loaded with hydrogen-active metal and alumina loaded with hydrogen-active metal. The average pore size of the alumina is higher than that of the ZSM-5 molecular sieve. The average pore size is based on the support without hydrogen-active metal loading. The average pore size of the alumina is 2-15 nm higher than that of the ZSM-5 molecular sieve; The ZSM-5 molecular sieve contains two types, which are referred to as ZSM-5 molecular sieve 1 and ZSM-5 molecular sieve 2, respectively. The average pore size of ZSM-5 molecular sieve 1 is 2-10 nm lower than that of ZSM-5 molecular sieve 2; The weight percentage of hydrogenated active metal loaded in ZSM-5 molecular sieve 1, calculated as hydrogenated active metal oxide, is 3-25 wt% lower than that of hydrogenated active metal loaded in ZSM-5 molecular sieve 2, calculated as hydrogenated active metal oxide. The weight basis is based on ZSM-5 molecular sieve 1 and ZSM-5 molecular sieve 2 loaded with hydrogenated active metal, respectively. The preparation method of the diesel hydroponic dewaxing catalyst includes the following: (1) Select or prepare ZSM-5 molecular sieve 1, and introduce hydrogenated active metal into ZSM-5 molecular sieve 1; (2) Select or prepare ZSM-5 molecular sieve 2, and introduce hydrogenated active metal into ZSM-5 molecular sieve 2; (3) Select or prepare alumina, and introduce hydrogenated active metals into the alumina; (4) The materials obtained in steps (1), (2) and (3) are mixed and molded to obtain the final diesel hydrodewaxing catalyst.

2. The catalyst according to claim 1, characterized in that: The average pore size of the alumina is 4~10 nm higher than that of the ZSM-5 molecular sieve.

3. The catalyst 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.

4. The catalyst according to claim 1, characterized in that: The active metal for hydrogenation is one or more of iron, chromium, molybdenum, tungsten, cobalt, nickel, or their sulfides or oxides.

5. The catalyst according to claim 3, characterized in that: Based on the total weight of the diesel hydrodewaxing catalyst, the content of hydroactive metals, calculated as metal oxides, is 5-35 wt%; of which the content of Group VIIB or Group VIII hydroactive metal oxides is 2-8 wt%; and the content of Group VIB hydroactive metal oxides is 3-30 wt%.

6. The catalyst according to claim 5, characterized in that: Based on the total weight of the diesel hydrodewaxing catalyst, the content of hydroactive metal, calculated as metal oxide, is 6~25 wt%.

7. The catalyst according to claim 1, characterized in that: Alumina loaded with hydrogenation active metals accounts for 20-60 wt% of the total weight of the final diesel hydrodewaxing catalyst.

8. The catalyst according to claim 7, characterized in that: Alumina loaded with hydrogenation active metals accounts for 25-50 wt% of the total weight of the final diesel hydrodewaxing catalyst.

9. The catalyst according to claim 3, characterized in that: Based on the weight of the hydrogenated active metal alumina, the mass content of the hydrogenated active metal as oxide is 4~25 wt%; of which the mass content of Group VIIB or Group VIII hydrogenated active metal oxide is 1~8 wt%; and the mass content of Group VIB hydrogenated active metal oxide is 3~25 wt%.

10. The catalyst according to claim 9, characterized in that: Based on the weight of the hydrogenated active metal alumina, the mass content of the hydrogenated active metal as oxide is 8~20 wt%; of which the mass content of Group VIIB or Group VIII hydrogenated active metal oxide is 2~6 wt%; and the mass content of Group VIB hydrogenated active metal oxide is 4~20 wt%.

11. The catalyst according to claim 1, characterized in that: The average pore size of ZSM-5 molecular sieve 1 is 3-8 nm smaller than that of ZSM-5 molecular sieve 2.

12. The catalyst according to claim 11, characterized in that: The average pore size of ZSM-5 molecular sieve 1 is 4-6 nm smaller than that of ZSM-5 molecular sieve 2.

13. The catalyst according to claim 1, characterized in that: The ZSM-5 molecular sieve 1 has an average pore size of 1~4 nm, and the ZSM-5 molecular sieve 2 has an average pore size of 4~12 nm.

14. The catalyst according to claim 1, characterized in that: The weight percentage of hydrogenated active metal loaded in ZSM-5 molecular sieve 1, calculated as hydrogenated active metal oxide, is 5-20 wt% lower than that of hydrogenated active metal loaded in ZSM-5 molecular sieve 2, calculated as hydrogenated active metal oxide. The weight basis is based on ZSM-5 molecular sieve 1 and ZSM-5 molecular sieve 2 loaded with hydrogenated active metal, respectively.

15. The catalyst according to claim 14, characterized in that: The weight percentage of hydrogenated active metal loaded in ZSM-5 molecular sieve 1, calculated as hydrogenated active metal oxide, is 6-18 wt% lower than that of hydrogenated active metal loaded in ZSM-5 molecular sieve 2, calculated as hydrogenated active metal oxide. The weight basis is based on ZSM-5 molecular sieve 1 and ZSM-5 molecular sieve 2 loaded with hydrogenated active metal, respectively.

16. The catalyst according to claim 3, characterized in that: In the ZSM-5 molecular sieve 1 loaded with hydrogenated active metal, based on the weight of the ZSM-5 molecular sieve 1 loaded with hydrogenated active metal, the mass content of the hydrogenated active metal as an oxide is 1~6 wt%; among which, the mass content of Group VIIB or Group VIII hydrogenated active metal oxide is 0~2 wt%, and the mass content of Group VIB hydrogenated active metal oxide is 0~4 wt%.

17. The catalyst according to claim 16, characterized in that: In ZSM-5 molecular sieve 1 loaded with hydrogenated active metal, the hydrogenated active metal is in the form of oxides with a mass content of 1~5 wt%, based on the weight of ZSM-5 molecular sieve 1 loaded with hydrogenated active metal.

18. The catalyst according to claim 3, characterized in that: In the ZSM-5 molecular sieve 2 loaded with hydrogenated active metal, based on the weight of the ZSM-5 molecular sieve 2 loaded with hydrogenated active metal, the mass content of the hydrogenated active metal as an oxide is 3~30 wt%; among which, the mass content of Group VIIB or Group VIII hydrogenated active metal oxide is 1~6 wt%; and the mass content of Group VIB hydrogenated active metal oxide is 2~24 wt%.

19. The catalyst according to claim 18, characterized in that: In the ZSM-5 molecular sieve 2 loaded with hydrogenated active metal, based on the weight of the ZSM-5 molecular sieve 2 loaded with hydrogenated active metal, the mass content of the hydrogenated active metal as an oxide is 5~25 wt%; among which, the mass content of Group VIIB or Group VIII hydrogenated active metal oxide is 2~5 wt%; and the mass content of Group VIB hydrogenated active metal oxide is 4~20 wt%.

20. The catalyst according to claim 1, characterized in that: ZSM-5 molecular sieve 1, supported on hydrogenated active metal, accounts for 2 to 20 wt% of the total weight of the final diesel hydrodewaxing catalyst.

21. The catalyst according to claim 20, characterized in that: ZSM-5 molecular sieve 1, supported on hydrogenated active metal, accounts for 4 to 16 wt% of the total weight of the final diesel hydrodewaxing catalyst.

22. The catalyst according to claim 1, characterized in that: ZSM-5 molecular sieve 2, supported on hydrogenated active metal, accounts for 5-30 wt% of the total weight of the final diesel hydrodewaxing catalyst.

23. The catalyst according to claim 22, characterized in that: ZSM-5 molecular sieve 2, supported on hydrogenated active metal, accounts for 8-25 wt% of the total weight of the final diesel hydrodewaxing catalyst.

24. The method for preparing the diesel hydrodewaxing catalyst according to any one of claims 1 to 23, characterized in that: The method includes the following: (1) Select or prepare ZSM-5 molecular sieve 1, and introduce hydrogenated active metal into ZSM-5 molecular sieve 1; (2) Select or prepare ZSM-5 molecular sieve 2, and introduce hydrogenated active metal into ZSM-5 molecular sieve 2; (3) Select or prepare alumina, and introduce hydrogenated active metals into the alumina; (4) The materials obtained in steps (1), (2) and (3) are mixed and molded to obtain the final diesel hydrodewaxing catalyst.

25. The method according to claim 24, characterized in that: The hydrogenated active metal is introduced in step (1) and / or step (2) and / or step (3) by impregnation. After impregnation, the metal is left to stand for 2 to 20 hours to dry, then placed in an oven at 50 to 160°C to dry for 4 to 120 hours, and then calcined in a muffle furnace at 350 to 650°C for 2 to 18 hours to obtain intermediate material powder.

26. The method according to claim 25, characterized in that: The intermediate material powders obtained in steps (1), (2) and (3) are mixed with the binder and then kneaded into shape.

27. The method according to claim 26, characterized in that: The adhesive is one or more of aluminum sol, silica sol, silica-alumina sol, polyethylene glycol, and phospho-alumina sol.

28. The method according to claim 26, characterized in that: The adhesive is a soluble pseudoboehmite.

29. The method according to claim 24, characterized in that: The catalyst is in the shape of a toothed ball, clover, four-leaf clover, or cylindrical strip; the diameter of the toothed ball catalyst is 1.5 to 10.0 mm; the length of the clover, four-leaf clover, or cylindrical strip is 1.4 to 10.0 mm, and the diameter is 1.0 to 6.0 mm.

30. The application of the diesel hydrodewaxing catalyst according to any one of claims 1 to 23 in diesel hydrodewaxing.

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