Preparation method and application of hydrocracking catalyst for increasing yield of middle distillates

Abstract

The invention discloses a preparation method and application of a hydrocracking catalyst capable of increasing middle distillate yield, and the preparation method comprises the following steps: mixing an acidic solution containing P123, a silicon source and an aluminum source, crystallizing, washing, drying and roasting to obtain an Al-KIT-6 molecular sieve; immersing acidic cation exchange resin into the active metal impregnation liquid for pretreatment; mixing an Al-KIT-6 molecular sieve, the pretreated acidic cation exchange resin, amorphous silica-alumina, aluminum oxide and an extrusion aid to obtain mixed powder; mixing the mixed powder with deionized water and a binder, and performing extrusion molding, drying and roasting to obtain a catalyst carrier; and immersing the catalyst carrier in the active metal impregnation liquid for impregnation, curing, drying and roasting to obtain the catalyst. According to the method, an Al-KIT-6 molecular sieve is adopted as a carrier to synthesize the hydrocracking catalyst, and the molecular sieve has the advantages of large specific surface area and regular and ordered pore channels.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a method for preparing and applying a hydrocracking catalyst that produces more middle distillate oil. Background Technology

[0002] Currently, my country faces overcapacity in oil refining. In 2022, my country's total refining capacity reached 924 million tons per year, but its processing volume was only 680 million tons, indicating overcapacity. The average refinery operating rate was 73.6% (compared to the global average of 79%). Public data shows that in 2022, domestic crude oil processing volume declined year-on-year for the first time, meaning that my country's primary crude oil processing capacity was oversupplied by more than 200 million tons. National refined oil consumption was 345 million tons, a slight increase of 0.9% year-on-year. my country's refining capacity exhibits significant structural contradictions. This is reflected in the fact that gasoline and diesel consumption has entered a plateau period, and the consumption of aviation kerosene alone is expected to increase from the current 30 million tons to 80 million tons by 2035. The market demand for basic chemical raw materials, represented by aromatics and olefins, is also expected to grow. Therefore, the production model of the refining industry will inevitably shift from oil refining to chemical production. Increasing the production of chemical raw materials and simultaneously producing aviation kerosene will become the main development direction for refining enterprises to adjust their product structure and improve quality and efficiency.

[0003] Hydrocracking technology is a crucial method for the deep processing of heavy oil fractions. It can directly convert inferior and heavy feedstocks into chemical feedstocks (including ethylene feedstocks and reforming feedstocks) and clean oil products (jet kerosene and diesel). It features high liquid yield, strong feedstock adaptability, and good production flexibility, making it a key technology for the transformation and upgrading of the refining and chemical industry. Hydrocracking processes are divided into single-stage and two-stage processes. Compared to single-stage processes, two-stage hydrocracking technology can perform secondary conversion of unconverted tail oil from the first stage, offering better feedstock adaptability, higher conversion rates, and meeting more flexible production needs. Furthermore, two-stage hydrocracking is also one solution to address the future trend towards larger-scale plants.

[0004] In foreign companies such as UOP and CLG, two-stage hydrocracking processes and catalyst technologies are more common. Examples include UOP's HC-310LT and HC-320LT catalysts, primarily used in the second-stage reactors of two-stage hydrocracking units, and CLG's ICR 240 catalyst containing a small amount of molecular sieves. In China, the Sinopec Fushun (Dalian) Petrochemical Research Institute possesses two-stage hydrocracking technology, such as the FMD2 two-stage hydrocracking technology for maximum production of middle distillate oils and the FMC2 two-stage hydrocracking technology for high-quality chemical feedstock production. However, catalysts specifically developed for the second stage of two-stage processes are almost nonexistent. Therefore, this patent develops a hydrocracking catalyst for high-yield middle distillate oil production specifically for the second stage of two-stage processes.

[0005] The core of hydrocracking technology is the hydrocracking catalyst, which consists of a metallic active component and acidic centers. Suitable catalyst pore structure and acidic center properties play a decisive role in regulating the yield of middle distillate oil and product distribution. During the hydrocracking reaction, heavy distillate oil can be hydrogenated to saturation and undergo ring-opening cracking, converting it into middle distillate oil after primary cracking. To achieve a two-stage, high-yield middle distillate oil hydrocracking process, the development of a high-yield second-stage hydrocracking catalyst has become the core and key to this technology. Current research indicates that the catalyst's pore structure and acidic center properties determine its hydrocracking performance.

[0006] CN117943111A discloses a hydrocracking catalyst for producing high-yield lubricating oil base oils and its preparation method. The hydrocracking catalyst comprises a support and an active metal component supported on the support; based on the total mass of the hydrocracking catalyst, the content of the support is 2-99% by weight; the support contains a non-amorphous mesoporous acidic material and a molecular sieve, the molecular sieve including a twelve-membered ring three-dimensional macroporous molecular sieve and a ten-membered ring one-dimensional mesoporous molecular sieve; the content of the molecular sieve in the support is 20-90% by weight, and the weight ratio of the twelve-membered ring three-dimensional macroporous molecular sieve to the ten-membered ring one-dimensional mesoporous molecular sieve is 0.1-40:1. Using the catalyst provided in this disclosure to process heavy distillate oils significantly improves the selectivity of middle distillate oils and the yield of jet fuel, significantly increases the viscosity index of tail oil, and significantly reduces the pour point.

[0007] CN117380259A discloses a hydrocracking catalyst for producing middle distillate oil, its preparation method, and its application. The method includes the preparation of a support and the loading of a hydrocracking active metal. The support preparation method includes: mixing and molding ZSM-23 molecular sieve, Y molecular sieve, amorphous silica-alumina, and a binder, followed by drying and calcination to prepare the catalyst support. The Y molecular sieve has the following properties: Na2O weight content less than 0.3%; SiO2 / Al2O3 molar ratio of 35–50; specific surface area of ​​600–900 m² / g. 2 / g; pore volume is 0.4~0.7mL / g; the properties of the ZSM-23 molecular sieve are as follows: specific surface area is 300-430m² / g. 2 / g, pore volume is 0.31-0.5cm 3 / g, microporous specific surface area is 50-170m² 2 / g, mesoporous specific surface area is 150-310m² 2 / g; preferably, the specific surface area is 320-405m². 2 / g, pore volume is 0.34-0.45cm³ 3 / g, microporous specific surface area is 80-140m² 2 / g, mesoporous specific surface area is 261-295m² 2 / g. The catalyst prepared by the method exhibits high selectivity for medium-grade oil in the hydrocracking reaction of heavy feedstock, while also possessing characteristics such as low freezing point of jet fuel and low pour point of diesel oil.

[0008] CN116060111A discloses a catalyst for hydrocracking of middle distillate oil, its preparation method, and its application. The catalyst, based on its weight, comprises: an active metal content of 4 wt% to 40 wt% (based on oxides); and a support content of 60 wt% to 96 wt%. The support, based on its total mass, comprises: 10 wt% to 15 wt% Al-SBA-15 / β core-shell composite molecular sieve, 5 wt% to 15 wt% Y molecular sieve, 20 wt% to 60 wt% amorphous silica-alumina, and 15 wt% to 50 wt% binder components. This catalyst is suitable for heavy oil hydrocracking reactions, exhibiting high activity and selectivity for middle distillate oil, and producing good product properties.

[0009] CN113019426A discloses a hydrocracking catalyst support, a hydrocracking catalyst, and its preparation method. The support comprises a Y / Al-SBA-15 composite molecular sieve and alumina. The Y / Al-SBA-15 composite molecular sieve has a medium-strong acid content of 0.6–1.2 mL / g and a Brønsted acid to Lewis acid ratio of less than 1.2. The preparation method of the Y / Al-SBA-15 composite molecular sieve used in this support includes: using amorphous silica-alumina dry gel as raw material, and employing P123 triblock copolymer as a template agent for a first crystallization to synthesize Al-SBA-15 molecular sieve, followed by the addition of ultrastable Y molecular sieve slurry, and a second crystallization to obtain the Y / Al-SBA-15 composite molecular sieve. Using the hydrocracking catalyst of this invention in the hydrocracking reaction, the yield of heavy naphtha is 35–40 wt%, and the aromatic potential is approximately 60 wt%.

[0010] CN115999618A discloses a hydrocracking catalyst and its preparation method. The method includes the following steps: 1) mixing nickel nitrate with an acidic aqueous solution to obtain a mixed liquid; 2) mixing the mixed liquid obtained in step 1) with a base material, molecular sieve, additives, and a second active ingredient or its precursor to obtain a mixed material; 3) sequentially molding, drying, and calcining the mixed material obtained in step 3); wherein, relative to 1 kg of nickel nitrate, the amount of the acidic aqueous solution is 1-8 kg. The method provided by this invention enables continuous preparation of the hydrocracking catalyst, resulting in higher uniformity of metal components among the catalyst particles, which is beneficial for the uniformity of the catalyst's intrinsic activity. Summary of the Invention

[0011] The purpose of this invention is to provide a method for preparing a hydrocracking catalyst that yields more middle distillate oil and its application. The catalyst prepared by the method of this invention, incorporating acidic cation exchange resin material, significantly improves the selectivity and conversion rate of feedstock molecules, and its application in hydrocracking reactions can significantly increase the yield of middle distillate oil.

[0012] To achieve the above objectives, the present invention provides a method for preparing a hydrocracking catalyst that yields a large amount of middle distillate oil, comprising the following steps:

[0013] S1, mix an acidic solution containing P123, a silicon source, and an aluminum source, crystallize, wash, dry, and calcine to obtain Al-KIT-6 molecular sieve;

[0014] S2, the acidic cation exchange resin is pretreated by immersing it in an active metal impregnation solution;

[0015] S3, the Al-KIT-6 molecular sieve, the pretreated acidic cation exchange resin, amorphous silica-alumina, alumina and extrusion aid are mixed to obtain a mixed powder;

[0016] S4, the mixed powder is mixed with deionized water and binder, extruded into strips, dried and calcined to obtain a catalyst support;

[0017] S5, the catalyst support is immersed in an active metal impregnation solution for impregnation, conditioning, drying, and calcination to obtain the catalyst.

[0018] The method for preparing a hydrocracking catalyst for producing more middle distillate oil according to the present invention uses an acidic cation exchange resin, which is a sulfonic acid type cation exchange resin.

[0019] The method for preparing a hydrocracking catalyst for producing more middle distillate oil according to the present invention includes an active metal comprising at least one of Group VIB and Group VIII metals, wherein the Group VIB metal is molybdenum and / or tungsten, and the Group VIII metal is cobalt and / or nickel. The active metal in the catalyst, calculated as oxide, comprises 20 to 45 wt% of the total mass of Al-KIT-6 molecular sieve, acidic cation exchange resin, amorphous silica and alumina, and alumina.

[0020] In the preparation method of the hydrocracking catalyst for producing more middle distillate oil according to the present invention, the mass ratio of P123, silicon source and aluminum source in step S1 is 1:(1.9~2.4):(0.02~0.35), wherein the silicon source is calculated as SiO2 and the aluminum source is calculated as Al2O3.

[0021] The method for preparing the hydrocracking catalyst for producing more middle distillate oil according to the present invention comprises a catalyst support of 100% by mass, wherein the mass content of Al-KIT-6 molecular sieve in the catalyst support is 45-65% by mass; and the mass ratio of Al-KIT-6 molecular sieve, alumina, pretreated acidic cation exchange resin, and amorphous silica-alumina is 1:(1.4-2.5):(1.9-3.0):(4.2-6.1).

[0022] The preparation method of the hydrocracking catalyst for producing more middle distillate oil according to the present invention includes the following steps in step S1: crystallization conditions are 90-120℃ for 18-30 h; calcination conditions are 500-560℃ for 3-6 h.

[0023] In the preparation method of the hydrocracking catalyst for producing more middle distillate oil according to the present invention, the drying in step S4 is freeze drying; the calcination conditions are calcination at 480-550℃ for 3-5 hours.

[0024] The preparation method of the hydrocracking catalyst for producing more middle distillate oil according to the present invention includes the following steps: in step S5, the conditioning is carried out in a closed container for 2-3 hours; the drying is freeze drying; and the calcination conditions are calcination at 480-550℃ for 3-5 hours.

[0025] The method for preparing a hydrocracking catalyst for producing high-yield middle distillate oil according to the present invention, wherein the catalyst has a specific surface area of ​​280-340 m². 2 / g, pore volume is 0.27~0.42mL / g, pore size is 7.6~11.1nm.

[0026] To achieve the above objectives, the present invention also provides an application of the catalyst prepared by the above-described method in hydrocracking, wherein the hydrocracking reaction temperature is 290–395°C, the reaction pressure is 6–16 MPa, the hydrogen-to-oil volume ratio is 500–1500:1, and the liquid hourly space velocity is 0.5–2.5 h⁻¹. -1 .

[0027] Beneficial effects of this invention:

[0028] An acidic cation exchange resin material is used to synthesize the support. This material has large pores, a large specific surface area, numerous active sites, and a fast ion diffusion rate. The catalyst prepared using this material has an increased specific surface area and larger pores, making it easier for feedstock oil molecules to diffuse close to the active sites, effectively improving the selectivity and conversion rate of middle distillate oils.

[0029] An acidic cation exchange resin material is used to synthesize the support, which can also perform ion exchange. During metal impregnation, the chemically active groups in the cation exchange resin support can exchange with the W-Ni metal cations in the impregnation solution, impregnating the W-Ni metal into the catalyst support. This method can better load the metal into the catalyst, increase the metal loading, and thus improve the catalytic activity of the catalyst.

[0030] This method uses Al-KIT-6 molecular sieve, modified from pure silicon molecular sieve KIT-6, as a support to synthesize a hydrocracking catalyst. This molecular sieve has the advantages of large specific surface area and regular and ordered pores. The KIT-6 molecular sieve is modified with Al to make it acidic, which can improve the activity of the molecular sieve. Detailed Implementation

[0031] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0032] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified. Among them, the triblock copolymer P123(EO) 20 PO 70 EO 20 (Molecular weight = 5800, Sigma-Aldrich (Shanghai) Co., Ltd.), Tetraethyl orthosilicate (Si(C2H5O)4) (Tianjin Damao Chemical Reagent Factory, AR), Aluminum isopropoxide (Al(OiPr)3) (Tianjin Damao Chemical Reagent Factory, CR), Alumina (Tianjin Kaivent Technology Co., Ltd., purity 70%), Amorphous silica-alumina (Tianjin Kaivent Technology Co., Ltd., purity 70%), Sulfonic acid type strong acid cation exchange resin (Maclean's reagent, AR), Ammonium metatungstate (Merck reagent, WO3 content 85%), Nickel nitrate (Merck reagent, Ni content 25%), Guargan oil (Zhengzhou Yuhe Food Additives Co., Ltd., purity 100%), Citric acid (brand innochem, purity 99%), Nitric acid (Tianjin Kemio Chemical Reagent Co., Ltd., purity 63%).

[0033] Analytical testing methods: Specific surface area and pore volume were tested on an ASAP2020M specific surface area and porosity analyzer manufactured by Micromeritics. Specific surface area was calculated according to the BET method; pore volume was calculated according to the BJH method. Specific implementation examples:

[0035] Example 1

[0036] (1) An acidic solution containing P123, tetraethyl orthosilicate, and aluminum isopropoxide were mixed, crystallized at 90°C for 18 h, washed, dried, and calcined at 500°C for 6 h to obtain Al-KIT-6 molecular sieve, wherein the mass ratio of P123, tetraethyl orthosilicate (calculated as SiO2), and aluminum isopropoxide (calculated as Al2O3) was 1:1.9:0.35;

[0037] (2) The sulfonic acid type strong acid cation exchange resin was pretreated by immersing it in an aqueous solution of W-Ni metal ions obtained by mixing 13.5g ammonium metatungstate and 8.9g nickel nitrate.

[0038] (3) Weigh 20g of Al-KIT-6 molecular sieve, then weigh 122g of amorphous silica-alumina, 60g of pretreated sulfonic acid-type strong acid cation exchange resin, 28g of alumina and 5.0g of guar gum powder and mix them evenly. This mixture is called A mixed powder.

[0039] (4) Mix the A mixed powder with deionized water, 1.5g citric acid and 4.5g nitric acid evenly, and record it as solid B.

[0040] (5) The solid B was extruded into strips, freeze-dried for 4 hours, and calcined at 540°C for 4 hours to obtain carrier A.

[0041] (6) Weigh out 20.3g of ammonium metatungstate and 13.4g of nickel nitrate and mix them together. Prepare an equal volume of impregnation solution according to the water absorption rate of the carrier, and denot it as reagent C.

[0042] (7) Impregnate carrier A with reagent C, cure in a sealed container for 2 hours, freeze dry for 4 hours, and calcine at 500°C for 4 hours to obtain catalyst A.

[0043] Example 2

[0044] (1) An acidic solution containing P123, tetraethyl orthosilicate, and aluminum isopropoxide were mixed, crystallized at 100°C for 25 h, washed, dried, and calcined at 550°C for 3 h to obtain Al-KIT-6 molecular sieve, wherein the mass ratio of P123, tetraethyl orthosilicate (calculated as SiO2), and aluminum isopropoxide (calculated as Al2O3) was 1:2.4:0.02;

[0045] (2) The sulfonic acid type strong acid cation exchange resin was pretreated by immersing it in an aqueous solution of W-Ni metal ions obtained by mixing 20.8g ammonium metatungstate and 13.8g nickel nitrate.

[0046] (3) Weigh 24g of Al-KIT-6 molecular sieve, then weigh 123.6g of amorphous silica-alumina, 58.8g of pretreated sulfonic acid-type strong acid cation exchange resin, 46.8g of alumina and 5.0g of guar gum powder and mix them evenly. This mixture is called A mixed powder.

[0047] (4) Mix the A mixed powder with deionized water, 1.5g citric acid and 4.5g nitric acid evenly, and record it as solid B.

[0048] (5) The solid B was extruded into strips, freeze-dried for 4 hours, and calcined at 480°C for 5 hours to obtain carrier B.

[0049] (6) Weigh out 31.3g of ammonium metatungstate and 20.7g of nickel nitrate and mix them together. Prepare an equal volume of impregnation solution according to the water absorption rate of the carrier, and denot it as reagent C.

[0050] (7) Impregnate carrier A with reagent C, cure in a sealed container for 3 hours, freeze dry for 4 hours, and calcine at 480°C for 5 hours to obtain catalyst B.

[0051] Example 3

[0052] (1) An acidic solution containing P123, tetraethyl orthosilicate, and aluminum isopropoxide were mixed, crystallized at 120°C for 30 h, washed, dried, and calcined at 560°C for 6 h to obtain Al-KIT-6 molecular sieve, wherein the mass ratio of P123, tetraethyl orthosilicate (calculated as SiO2), and aluminum isopropoxide (calculated as Al2O3) was 1:2.15:0.04.

[0053] (2) The sulfonic acid type strong acid cation exchange resin was pretreated by immersing it in an aqueous solution of W-Ni metal ions obtained by mixing 29.5g of ammonium metatungstate and 19.5g of nickel nitrate.

[0054] (3) Weigh 29g of Al-KIT-6 molecular sieve, then weigh 121.8g of amorphous silica-alumina, 55.1g of pretreated sulfonic acid-type strong acid cation exchange resin, 72.5g of alumina and 5.0g of guar gum powder and mix them evenly. This mixture is called A mixed powder.

[0055] (4) Mix the A mixed powder with deionized water, 1.5g citric acid and 4.5g nitric acid evenly, and record it as solid B.

[0056] (5) The solid B was extruded into strips, freeze-dried for 4 hours, and calcined at 550°C for 3 hours to obtain carrier C.

[0057] (6) Weigh out 44.2g of ammonium metatungstate and 29.2g of nickel nitrate and mix them together. Prepare an equal volume of impregnation solution according to the water absorption rate of the carrier, and denot it as reagent C.

[0058] (7) Impregnate carrier A with reagent C, cure in a sealed container for 2 hours, freeze dry for 4 hours, and calcine at 550°C for 3 hours to obtain catalyst C.

[0059] Example 4

[0060] (1) An acidic solution containing P123, tetraethyl orthosilicate, and aluminum isopropoxide were mixed, crystallized at 90°C for 25 h, washed, dried, and calcined at 500°C for 4 h to obtain Al-KIT-6 molecular sieve, wherein the mass ratio of P123, tetraethyl orthosilicate (calculated as SiO2), and aluminum isopropoxide (calculated as Al2O3) was 1:2.15:0.04.

[0061] (2) The sulfonic acid type strong acid cation exchange resin was pretreated by immersing it in an aqueous solution of W-Ni metal ions obtained by mixing 13.5g ammonium metatungstate and 8.9g nickel nitrate.

[0062] (3) Weigh 20g of Al-KIT-6 molecular sieve, then weigh 122g of amorphous silica-alumina, 60g of pretreated sulfonic acid-type strong acid cation exchange resin, 28g of alumina and 5.0g of guar gum powder and mix them evenly. This mixture is called A mixed powder.

[0063] (4) Mix the A mixed powder with deionized water, 1.5g citric acid and 4.5g nitric acid evenly, and record it as solid B.

[0064] (5) The solid B was extruded into strips, freeze-dried for 4 hours, and calcined at 540°C for 4 hours to obtain carrier D.

[0065] (6) Weigh out 20.3g of ammonium metatungstate and 13.4g of nickel nitrate and mix them together. Prepare an equal volume of impregnation solution according to the water absorption rate of the carrier, and denot it as reagent C.

[0066] (7) Impregnate carrier A with reagent C, cure in a sealed container for 2 hours, freeze dry for 4 hours, and calcine at 500°C for 4 hours to obtain catalyst D.

[0067] Example 5

[0068] (1) An acidic solution containing P123, tetraethyl orthosilicate, and aluminum isopropoxide were mixed, crystallized at 110°C for 20 h, washed, dried, and calcined at 520°C for 5 h to obtain Al-KIT-6 molecular sieve, wherein the mass ratio of P123, tetraethyl orthosilicate (calculated as SiO2), and aluminum isopropoxide (calculated as Al2O3) was 1:2.4:0.02;

[0069] (2) The sulfonic acid type strong acid cation exchange resin was pretreated by immersing it in an aqueous solution of W-Ni metal ions obtained by mixing 29.5g of ammonium metatungstate and 19.5g of nickel nitrate.

[0070] (3) Weigh 29g of Al-KIT-6 molecular sieve, then weigh 121.8g of amorphous silica-alumina, 55.1g of pretreated sulfonic acid-type strong acid cation exchange resin, 72.5g of alumina and 5.0g of guar gum powder and mix them evenly. This mixture is called A mixed powder.

[0071] (4) Mix the A mixed powder with deionized water, 1.5g citric acid and 4.5g nitric acid evenly, and record it as solid B.

[0072] (5) The solid B was extruded into strips, freeze-dried for 4 hours, and calcined at 540°C for 4 hours to obtain carrier E.

[0073] (6) Weigh out 44.2g of ammonium metatungstate and 29.2g of nickel nitrate and mix them together. Prepare an equal volume of impregnation solution according to the water absorption rate of the carrier, and denot it as reagent C.

[0074] (7) Impregnate carrier A with reagent C, cure in a sealed container for 2 hours, freeze dry for 4 hours, and calcine at 500°C for 4 hours to obtain catalyst E.

[0075] Comparative Example 1

[0076] (1) Weigh 20g of Y molecular sieve, then weigh 122g of amorphous silica-alumina, 28g of alumina and 5.0g of guar gum powder and mix them evenly. This mixture is called A mixed powder.

[0077] (2) Mix the A mixed powder with deionized water, 1.5g citric acid and 4.5g nitric acid evenly, and record it as solid B.

[0078] (3) The solid B was extruded into strips, dried at 120°C for 4 hours, and calcined at 550°C for 3 hours to obtain carrier F.

[0079] (4) Weigh out 33.8g of ammonium metatungstate and 22.4g of nickel nitrate and mix them together. Prepare an equal volume of impregnation solution according to the water absorption rate of the carrier, and record it as reagent C.

[0080] (5) Impregnate carrier A and reagent C in equal volumes, allow to grow for 2 hours, dry at 120°C for 4 hours, and calcine at 550°C for 3 hours to obtain catalyst F.

[0081] Comparative Example 2

[0082] (1) Weigh 29g of Y molecular sieve, then weigh 121.8g of amorphous silicon aluminum, 72.5g of alumina and 5.0g of guar powder and mix them evenly. This mixture is called A mixed powder.

[0083] (2) Mix the A mixed powder with deionized water, 1.5g citric acid and 4.5g nitric acid evenly, and record it as solid B.

[0084] (3) The solid B was extruded into strips, dried at 120°C for 4 hours, and calcined at 550°C for 3 hours to obtain the carrier G.

[0085] (4) Weigh out 73.7g of ammonium metatungstate and 48.7g of nickel nitrate and mix them together. Prepare an equal volume of impregnation solution according to the water absorption rate of the carrier, and denot it as reagent C.

[0086] (5) Impregnate carrier A and reagent C in equal volumes, allow to grow for 2 hours, dry at 120°C for 4 hours, and calcine at 550°C for 3 hours to obtain catalyst G.

[0087] Comparative Example 3

[0088] (1) An acidic solution containing P123, tetraethyl orthosilicate, and aluminum isopropoxide were mixed, crystallized at 120°C for 30 h, washed, dried, and calcined at 560°C for 6 h to obtain Al-KIT-6 molecular sieve, wherein the mass ratio of P123, tetraethyl orthosilicate (calculated as SiO2), and aluminum isopropoxide (calculated as Al2O3) was 1:2.15:0.04.

[0089] (2) Weigh 29g of Al-KIT-6 molecular sieve, then weigh 121.8g of amorphous silica-alumina, 72.5g of alumina and 5.0g of guar gum powder and mix them evenly. This mixture is called A mixed powder.

[0090] (3) Mix the A mixed powder with deionized water, 1.5g citric acid and 4.5g nitric acid evenly, and record it as solid B.

[0091] (4) The solid B was extruded into strips, freeze-dried for 4 hours, and calcined at 550°C for 3 hours to obtain the carrier H.

[0092] (5) Weigh out 73.7g of ammonium metatungstate and 48.7g of nickel nitrate and mix them together. Prepare an equal volume of impregnation solution according to the water absorption rate of the carrier, and record it as reagent C.

[0093] (6) Impregnate carrier A with reagent C, cure in a sealed container for 2 hours, freeze dry for 4 hours, and calcine at 550°C for 3 hours to obtain catalyst H.

[0094] Comparative Example 4

[0095] (1) An acidic solution containing P123, tetraethyl orthosilicate, and aluminum isopropoxide were mixed, crystallized at 120°C for 30 h, washed, dried, and calcined at 560°C for 6 h to obtain Al-KIT-6 molecular sieve, wherein the mass ratio of P123, tetraethyl orthosilicate (calculated as SiO2), and aluminum isopropoxide (calculated as Al2O3) was 1:2.15:0.04.

[0096] (2) Weigh 29g of Al-KIT-6 molecular sieve, then weigh 121.8g of amorphous silica-alumina, 55.1g of sulfonic acid-type strong acid cation exchange resin, 72.5g of alumina and 5.0g of guar gum powder and mix them evenly. This mixture is called A mixed powder.

[0097] (3) Mix the A mixed powder with deionized water, 1.5g citric acid and 4.5g nitric acid evenly, and record it as solid B.

[0098] (4) The solid B was extruded into strips, freeze-dried for 4 hours, and calcined at 550°C for 3 hours to obtain carrier I.

[0099] (5) Weigh out 73.7g of ammonium metatungstate and 48.7g of nickel nitrate and mix them together. Prepare an equal volume of impregnation solution according to the water absorption rate of the carrier, and record it as reagent C.

[0100] (6) Impregnate carrier A with reagent C, cure in a sealed container for 2 hours, freeze dry for 4 hours, and calcine at 550°C for 3 hours to obtain catalyst I.

[0101] Comparative Example 5

[0102] (1) Acidic solution containing P123 was mixed with tetraethyl orthosilicate, crystallized at 120°C for 30 h, washed, dried, and calcined at 560°C for 6 h to obtain KIT-6 molecular sieve, wherein the mass ratio of P123 to tetraethyl orthosilicate (calculated as SiO2) was 1:2.15.

[0103] (2) The sulfonic acid type strong acid cation exchange resin was pretreated by immersing it in an aqueous solution of W-Ni metal ions obtained by mixing 29.5g of ammonium metatungstate and 19.5g of nickel nitrate.

[0104] (3) Weigh 29g of Al-KIT-6 molecular sieve, then weigh 121.8g of amorphous silica-alumina, 55.1g of pretreated sulfonic acid-type strong acid cation exchange resin, 72.5g of alumina and 5.0g of guar gum powder and mix them evenly. This mixture is called A mixed powder.

[0105] (4) Mix the A mixed powder with deionized water, 1.5g citric acid and 4.5g nitric acid evenly, and record it as solid B.

[0106] (5) The solid B was extruded into strips, freeze-dried for 4 hours, and calcined at 550°C for 3 hours to obtain carrier J.

[0107] (6) Weigh out 44.2g of ammonium metatungstate and 29.2g of nickel nitrate and mix them together. Prepare an equal volume of impregnation solution according to the water absorption rate of the carrier, and denot it as reagent C.

[0108] (7) Impregnate carrier A with reagent C, cure in a sealed container for 2 hours, freeze dry for 4 hours, and calcine at 550°C for 3 hours to obtain catalyst J.

[0109] Table 1 Physical properties of catalysts

[0110]

[0111] Evaluation results of the catalysts prepared in the examples and comparative examples on the hydrocracking of hydrocracking tail oil in a 200 mL fixed bed hydrocracking unit.

[0112] The conventional refining agent was loaded into the first reactor at a loading volume of 60 mL; the catalyst and supplementary refining agent prepared in the examples and comparative examples were loaded into the second reactor at a loading volume of 60 / 6 mL. Sulfidation was then carried out using kerosene containing 2% carbon disulfide. The hydrocracking conditions were: reaction pressure 15 MPa, hydrogen-to-oil volume ratio 1000:1, and liquid hourly space velocity (LHSV) in the cracking section 1.5 h⁻¹. -1 The reaction temperatures for the first and second reactions are 380 and 340℃, respectively. The main properties of the feedstock are listed in Table 2, and the evaluation results are listed in Table 3.

[0113] Table 2 Properties of Raw Materials

[0114]

[0115]

[0116] Table 3 Evaluation Results

[0117]

[0118] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a hydrocracking catalyst that yields a large amount of middle distillate oil, characterized in that, Includes the following steps: S1, mix an acidic solution containing P123, a silicon source, and an aluminum source, crystallize, wash, dry, and calcine to obtain Al-KIT-6 molecular sieve; S2, the acidic cation exchange resin is pretreated by immersing it in an active metal impregnation solution; S3, the Al-KIT-6 molecular sieve, the pretreated acidic cation exchange resin, amorphous silica-alumina, alumina and extrusion aid are mixed to obtain a mixed powder; S4, the mixed powder is mixed with deionized water and binder, extruded into strips, dried and calcined to obtain a catalyst support; S5, the catalyst support is immersed in an active metal impregnation solution for impregnation, conditioning, drying, and calcination to obtain the catalyst.

2. The method for preparing the hydrocracking catalyst for producing multiple middle distillate oils according to claim 1, characterized in that, The acidic cation exchange resin is a sulfonic acid type cation exchange resin.

3. The method for preparing the hydrocracking catalyst for producing multiple middle distillate oils according to claim 1, characterized in that, The active metal includes at least one of Group VIB and Group VIII metals, wherein the Group VIB metal is molybdenum and / or tungsten, and the Group VIII metal is cobalt and / or nickel. The active metal in the catalyst, calculated as oxide, has a content of 20 to 45 wt% of the total mass of Al-KIT-6 molecular sieve, acidic cation exchange resin, amorphous silica and alumina, and alumina.

4. The method for preparing the hydrocracking catalyst for producing multiple middle distillate oils according to claim 1, characterized in that, In step S1, the mass ratio of P123, silicon source, and aluminum source is 1:(1.9~2.4):(0.02~0.35), where the silicon source is calculated as SiO2 and the aluminum source is calculated as Al2O3.

5. The method for preparing the hydrocracking catalyst for producing multiple middle distillate oils according to claim 1, characterized in that, With the catalyst support mass as 100%, the mass content of Al-KIT-6 molecular sieve in the catalyst support is 45-65%; the mass ratio of Al-KIT-6 molecular sieve, alumina, pretreated acidic cation exchange resin, and amorphous silica-alumina is 1:(1.4-2.5):(1.9-3.0):(4.2-6.1).

6. The method for preparing the hydrocracking catalyst for producing more middle distillate oil according to claim 1, characterized in that, In step S1, the crystallization conditions are 90–120℃ for 18–30 h; the calcination conditions are 500–560℃ for 3–6 h.

7. The method for preparing a hydrocracking catalyst for producing multiple middle distillate oils according to claim 1, characterized in that, In step S4, the drying is freeze-drying; the calcination conditions are calcination at 480-550℃ for 3-5 hours.

8. The method for preparing the hydrocracking catalyst for producing more middle distillate oil according to claim 1, characterized in that, In step S5, the conditioning process involves conditioning in a sealed container for 2–3 hours; the drying process involves freeze drying; and the calcination conditions are calcination at 480–550℃ for 3–5 hours.

9. The method for preparing a hydrocracking catalyst for producing multiple middle distillate oils according to claim 1, characterized in that, The catalyst has a specific surface area of ​​280–340 m². 2 / g, pore volume is 0.27~0.42mL / g, pore size is 7.6~11.1nm.

10. The application of the catalyst prepared by the method according to any one of claims 1 to 9 in hydrocracking, characterized in that, The hydrocracking reaction temperature is 290–395℃, the reaction pressure is 6–16 MPa, the hydrogen-to-oil volume ratio is 500–1500:1, and the liquid hourly space velocity is 0.5–2.5 h⁻¹. -1 .

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