Hydrocracking catalyst as well as preparation method and application thereof

Abstract

The invention discloses a hydrocracking catalyst as well as a preparation method and application thereof. The hydrocracking catalyst comprises, by weight, 10%-50% of a modified Y molecular sieve, 30%-70% of an adhesive and 20%-35% of hydrogenation active metal in terms of metal oxide. Comprising the following steps: (1) mixing a modified nano-cluster Y-type molecular sieve, an adhesive and hydrogenation active metal according to a certain proportion, then adding a peptizing agent (such as a nitric acid solution) into the mixture to prepare slurry, and carrying out mixing, kneading and extrusion molding; and (2) drying and roasting the extruded product obtained in the step (1) to obtain the hydrocracking catalyst. The hydrocracking catalyst prepared by the method has the advantages of strong conversion capability, low hydrogen consumption, high product liquid yield, low tail oil BMCI value and the like when used in a heavy oil hydrocracking process.

Description

Technical Field

[0001] The present invention belongs to the field of hydrocracking, and in particular relates to a hydrocracking catalyst and a preparation method and application thereof. Background Art

[0002] Hydrocracking technology is one of the main technological means for deep processing of heavy oil. It is also the only important technological means that can directly produce clean transportation fuels and high-quality chemical raw materials while lightening the raw materials. As the quality of my country's crude oil becomes heavier and worse year by year, the processing volume of high-sulfur crude oil increases year by year, and environmental protection requirements for the refining process itself and the quality of petroleum products become increasingly stringent, the market demand for clean fuel and high-quality chemical raw materials continues to grow, which puts higher and more stringent requirements on hydrocracking technology. Hydrocracking catalysts are the core of hydrocracking technology. They are mainly bifunctional catalysts composed of acidic carriers and hydrogenation-active metals. Therefore, how to effectively improve their catalytic activity and selectivity for target products is the research focus of improving catalysts. The development of highly active hydrocracking catalysts has important practical production significance.

[0003] Chinese patent CN114713274A discloses a medium-oil hydrocracking catalyst comprising 10-20 wt% modified Y molecular sieve, 30-70 wt% amorphous silica-alumina, 20-50 wt% binder, and 25-35 wt% active metal. The modified Y molecular sieve is a small-grain mesoporous modified Y molecular sieve with a framework silica-to-alumina molar ratio of 15-60, a sodium oxide content of less than 0.1 wt%, a unit cell parameter of 2.430-2.438 nm, a crystal particle size of less than 500 nm, and a mesoporosis index (M) of 1.7-5.0. Because the Y molecular sieve is modified using an alkali treatment in this method, resulting in severe collapse of the framework structure, the modified Y molecular sieve has a relative crystallinity of only 61-85%, resulting in insufficient catalytic activity of the hydrocracking catalyst and a high BMCI (10-13.2) in the tail oil product.

[0004] Patent CN111672534A provides a hydrocracking catalyst and its preparation method and application. The hydrocracking catalyst includes a carrier, a hydrogenation metal component and an auxiliary agent. The hydrogenation metal component and the auxiliary agent are in the form of metal oxides. The metal component includes oxides of Group VIB metals and oxides of Group VIII metals. The carrier is prepared from a Y-type zeolite / alumina composite material modified by ammonium fluorosilicate. The Y-type zeolite / alumina composite material modified by ammonium fluorosilicate is prepared by mixing activated alumina, a directing agent, a silicon source and water, hydrothermally crystallizing it, and modifying it with ammonium fluorosilicate. However, the relative crystallinity of the Y-type zeolite / alumina composite material prepared in situ by the invention is only 15%-49%, and the specific surface area is only 319m 2 / g-509m 2 / g, resulting in the hydrocracking catalyst prepared with it as an acidic carrier having weak ring-opening ability for polycyclic hydrocarbon macromolecules in heavy oil feedstock, and the BMCI of the tail oil product is relatively high (>10).

[0005] Chinese patent CN115193471A reports a heavy aromatic distillate hydrocracking catalyst and its application. The invention's heavy aromatic distillate hydrocracking catalyst comprises the following components by weight: 10%-90% of at least one of a Y molecular sieve or a β molecular sieve having a twelve-membered ring structure, 0.05%-0.15% of the precious metal Pt, the Group IVA element Sn added at a Sn / Pt molar ratio of 0.5-2.0, and the remainder being a binder. However, the hydrocracking catalyst prepared in this invention uses the precious metal Pt as the hydrogenation active metal, has stringent raw material quality requirements (sulfur and nitrogen contents must both be less than 5 ppm), and the catalyst's production cost is high.

[0006] Patent CN115315312A discloses a method for preparing a hydrocracking catalyst, which specifically comprises: a) providing a zeolite Y having a bulk silica to alumina ratio (SAR) of at least 10; b) mixing the zeolite Y provided in step a) with an alkali, water and a surfactant to obtain a slurry of the zeolite Y; c) reducing the water content of the slurry obtained in step b) to obtain a solid with reduced water content, wherein the reduction of the water content in step c) comprises adding a binder; d) shaping the solid with reduced water content obtained in step c) to obtain a shaped catalyst support; e) calcining the shaped catalyst support obtained in step d) at a temperature above 300° C. in the presence of the surfactant in step b) to obtain a calcined catalyst support; f) impregnating the catalyst support calcined in step e) with a hydrogenating component to obtain a supported catalyst; wherein no heat treatment at a temperature above 500° C. is performed between the mixing in step b) and the shaping in step d). In this method, the Y molecular sieve, which serves as the cracking acid component, suffers severe skeleton collapse after being modified with alkali and surfactants, and its relative crystallinity is only 33%-67% of that before modification, which reduces the cracking activity of the molecular sieve. This in turn leads to low catalytic activity of the hydrocracking catalyst and a reaction temperature as high as 398°C, greatly compressing the flexible adjustment operation space of the hydrocracking catalyst during its application.

[0007] In summary, various types of hydrocracking catalysts using molecular sieve materials as acidic supports are widely used in the processing of heavy feedstocks such as wax oil. However, they also face common practical challenges, such as significant room for improvement in catalyst activity, the need to further improve the quality of catalyst-processed products, and high production costs. Furthermore, with the increasing content of polycyclic macromolecules and macromolecular sulfur and nitrogen compounds in petroleum feedstocks, the processing of heavy oil molecules becomes more difficult and energy consumption increases. Furthermore, the mass transfer limitations of polycyclic macromolecules on hydrocracking catalysts become more severe. This can lead to deep cracking of heavy oil molecules due to untimely mass transfer, resulting in poor product selectivity, and can also easily lead to catalyst deactivation due to carbon deposition. Therefore, the development of low-cost hydrocracking catalysts with both higher catalytic activity and high product quality is urgently needed. Summary of the Invention

[0008] In view of the shortcomings of the prior art, the present invention provides a hydrocracking catalyst, a preparation method thereof, and its application. The catalyst prepared by the method has the advantages of high conversion capacity, low hydrogen consumption, high product liquid yield, and low tail oil BMCI value when used in the heavy oil hydrocracking process.

[0009] In a first aspect, the present invention provides a hydrocracking catalyst, comprising, based on the weight of the catalyst, 10%-50% of a modified Y molecular sieve, 30%-70% of a binder, and 20%-35% of a hydrogenation-active metal (calculated as metal oxide); wherein the modified Y molecular sieve is a modified nanoclustered Y molecular sieve; the binder is alumina; the hydrogenation-active metal is selected from Group VIII and / or Group VIB metals, wherein the Group VIII metal is Ni and / or Co, and the Group VIB metal is W and / or Mo, wherein the content of Group VIII as metal oxide is 5%-10%, and the content of Group VIB as metal oxide is 15%-25%, based on the weight of the catalyst; the average particle size of the modified nanoclustered Y molecular sieve is 500nm-2000nm, preferably 1000nm-1500nm; the pore volume of the modified nanoclustered Y molecular sieve is 0.4cm 3 / g-0.7cm 3 / g, preferably 0.5cm 3 / g-0.6cm 3 / g, the mesopore volume accounts for 30%-55%, preferably 40%-50%, the mesopore volume of 6nm-25nm accounts for more than 60% of the total mesopore volume, preferably 65%-95%, and more preferably 70%-90%; the specific surface area of ​​the modified nano-clustered Y molecular sieve is 700m 2 / g-900m 2 / g, preferably 750m 2 / g-850m 2 / g.

[0010] In the hydrocracking catalyst of the present invention, the mesopore distribution in the modified nano-clustered Y molecular sieve is 3-25 nm, wherein the volume of mesopores with a diameter of 3 nm to less than 6 nm accounts for 5%-30% of the total mesopore volume, preferably 10%-25%.

[0011] In the hydrocracking catalyst of the present invention, the average particle size of the nanoparticles constituting the modified nano-clustered Y molecular sieve clusters is about 30 nm to 100 nm, preferably 40 nm to 70 nm.

[0012] In the hydrocracking catalyst of the present invention, the modified nanoclustered Y molecular sieve has a typical FAU topological structure. Taking the unmodified nanoclustered Y molecular sieve as a standard sample, the relative crystallinity of the modified nanoclustered Y molecular sieve is 90%-110%, preferably 95%-105%.

[0013] In the hydrocracking catalyst of the present invention, the silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) of the modified nano-clustered Y molecular sieve is 8-50, preferably 10-30.

[0014] In the hydrocracking catalyst of the present invention, the pyridine infrared ion content of the modified nano-clustered Y molecular sieve is 0.3 mmol / g-1.2 mmol / g, preferably 0.5 mmol / g-1 mmol / g.

[0015] The second aspect of the present invention provides a method for preparing a hydrocracking catalyst, comprising the following contents:

[0016] (1) mixing the modified nano-clustered Y-type molecular sieve, a binder, and a hydrogenation active metal in a certain proportion, and then adding a peptizing agent (e.g., nitric acid solution) to the mixture to prepare a slurry, kneading, and extruding;

[0017] (2) drying and calcining the extrudate obtained in step (1) to obtain a hydrocracking catalyst.

[0018] In the method of the present invention, the mass fraction ratio of the modified Y-type molecular sieve, the binder and the hydrogenation active metal (calculated as metal oxide) in the solid mixture in step (1) is 10%-50%: 30%-70%: 20%-35%; the concentration of the nitric acid solution is 5-30% by mass; the solid content of the slurry is suitable for extrusion molding to obtain a strip-shaped extruded product, preferably, the solid content of the slurry is 30-60% by mass.

[0019] In the method of the present invention, the modified Y molecular sieve in step (1) is a modified nanoclustered Y molecular sieve with an average particle size of 500nm-2000nm, preferably 1000nm-1500nm; the pore volume of the modified nanoclustered Y molecular sieve is 0.4cm 3 / g-0.7cm 3 / g, preferably 0.5cm 3 / g-0.6cm 3 / g, the mesopore volume accounts for 30%-55%, preferably 40%-50%, the mesopore volume of 6nm-25nm accounts for more than 60% of the total mesopore volume, preferably 65%-95%, and more preferably 70%-90%; the specific surface area of ​​the modified nano-clustered Y molecular sieve is 700m 2 / g-900m 2 / g, preferably 750m 2 / g-850m 2 / g. In the modified nano-clustered Y molecular sieve, the mesopore distribution is 3-25nm, of which the mesopore volume of 3nm-less than 6nm accounts for 5%-30% of the total mesopore volume, preferably 10%-25%. The average particle size of the nanoparticles constituting the clusters of the modified nano-clustered Y molecular sieve is about 30nm-100nm, preferably 40nm-70nm. The modified nano-clustered Y molecular sieve has a typical FAU type topology. Taking the nano-clustered Y molecular sieve before modification as a standard sample, the relative crystallinity of the modified nano-clustered Y molecular sieve is 90%-110%, preferably 95%-105%. In the modified nano-clustered Y molecular sieve, the mass content of Na2O is less than 0.5%, preferably 0.05%-0.3%, based on weight. The silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) of the modified nano-clustered Y molecular sieve is 8-50, preferably 10-30. The modified nano-clustered Y molecular sieve has a pyridine infrared acid content of 0.3 mmol / g to 1.2 mmol / g, preferably 0.5 mmol / g to 1 mmol / g.

[0020] In the present invention, the binder in step (1) is γ-alumina, characterized in that the specific surface area is 200m 2 / g-600m 2 / g, preferably 300m 2 / g-500m 2 / g; pore volume 0.5cm 3 / g-1.5cm 3 / g, preferably 0.8cm 3 / g-1.2cm 3 / g.

[0021] In the present invention, the extruded product in step (2) is dried at 80-120° C. for 6-12 hours and then calcined at 400-500° C. for 1-5 hours.

[0022] Compared with the prior art, the hydrocracking catalyst of the present invention and its preparation method and application have the following beneficial effects:

[0023] The hydrocracking catalyst provided by the present invention adopts the modified nano-clustered Y molecular sieve as the acidic cracking component, and has the advantages of high catalytic activity, high liquid yield, low hydrogen consumption, low tail oil BMCI, etc. DETAILED DESCRIPTION

[0024] In the catalyst of the present invention, a non-limiting preparation method of the modified nano-clustered Y molecular sieve comprises: first preparing a nano-clustered Y molecular sieve, and then modifying the prepared nano-clustered Y molecular sieve. The process for preparing the nano-clustered Y molecular sieve is as follows: a mixture containing a silicon source, an aluminum source, an alkali source, carboxylated nanocellulose, and water is aged, crystallized, filtered, washed, dried, and calcined to obtain a final nano-clustered Y molecular sieve, wherein the mixture has a molar ratio of Na2O:Al2O3:SiO2:H2O=(3-6):1:(8-15):(150-500), preferably Na2O:Al2O3:SiO2:H2O=(4-5):1:(10-12):(250-350), and the mass ratio of carboxylated nanocellulose to silicon source (calculated by SiO2 content) is 0.01-0.05:1, preferably 0.02-0.04:1.

[0025] In the above-mentioned nano-clustered Y molecular sieve method, the silicon source is at least one of silica sol, water glass, ethyl orthosilicate and white carbon black, and silica sol is further preferred; the alkali source is sodium hydroxide; the aluminum source is at least one of sodium aluminate, aluminum isopropoxide, aluminum nitrate, aluminum chloride and aluminum sulfate, and sodium aluminate is preferred; the template agent is carboxylated nanocellulose purchased from MacLean Reagent Company, with a diameter of 4nm-10nm and a length of 100nm-200nm.

[0026] In the above-mentioned nanoclustered Y molecular sieve method, the mixing process of the materials can be carried out at room temperature, the mixing time is generally 1h-3h, and the mixing can be carried out under stirring conditions, and the stirring speed is generally 100r / min-1000r / min.

[0027] In the above-mentioned nano-clustered Y molecular sieve method, the silicon source, carboxylated nanocellulose and water are first uniformly mixed, then the alkali source is added, and finally the aluminum source is added to form a molecular sieve mother liquor. After uniform mixing, stirring, aging and crystallization are started.

[0028] In the above-mentioned nanoclustered Y molecular sieve method, the crystallization temperature is generally 80°C-110°C, preferably 95°C-105°C, and the crystallization time is generally 48h-168h, preferably 72h-120h.

[0029] In the above-mentioned nano-clustered Y molecular sieve method, solid-liquid separation is performed by filtration, and the product is washed with water until neutral. The drying temperature is 80-120°C and the drying time is 12-24 hours; the calcination temperature is 500-600°C and the calcination time is 2-6 hours.

[0030] The modification process of the prepared nano-clustered Y molecular sieve is as follows:

[0031] (a) controlling the sodium oxide content of the nanoclustered Y molecular sieve to 2.0%-4.5% by ion exchange treatment;

[0032] (b) using an ammonium fluorosilicate solution to shallowly dealuminate and resiliconize the nanoclustered Y molecular sieve obtained in step (a), wherein the shallow dealuminate and resiliconize refers to controlling the silicon-aluminum ratio of the nanoclustered Y molecular sieve after dealuminate and resiliconization to be increased by 50%-200%, preferably by 80%-150%, compared with the nanoclustered Y molecular sieve before treatment;

[0033] (c) subjecting the material obtained in step (b) to a hydrothermal dealumination treatment;

[0034] (d) The material after hydrothermal treatment is subjected to acid treatment to obtain modified nano-clustered Y molecular sieve.

[0035] In the method of the present invention, the nanoclustered Y molecular sieve can be prepared according to the synthesis method of the nanoclustered Y molecular sieve provided by the method of the present invention, or can be prepared according to existing public technology or using commercially available products, preferably prepared according to the synthesis method provided by the present invention.

[0036] In the above modification method, the specific process of the ion exchange in step (a) is as follows: the nanoclustered Y molecular sieve is subjected to ion exchange with a salt solution at 30-120° C., preferably 60-90° C., for 1-3 hours, and the number of exchanges is 1-3 times.

[0037] In the above modification method, the salt used in the ion exchange in step (a) is one or more of ammonium chloride, ammonium nitrate, ammonium sulfate, ammonium acetate, ammonium oxalate, sodium chloride and sodium nitrate, and the concentration of the salt solution is 0.5 mol / L-3 mol / L, preferably 1 mol / L-2 mol / L. The solid-to-liquid ratio of the nanoclustered Y molecular sieve to the salt solution is 1:5-15 (g:mL), preferably 1:8-10 (g:mL).

[0038] In the above modification method, in step (a), the nanoclustered Y molecular sieve contains an appropriate amount of sodium ions. Based on the weight of the nanoclustered Y molecular sieve, the mass content of sodium ions calculated as sodium oxide is 2.0%-4.5%, preferably 2.5%-4.0%.

[0039] The results show that an appropriate amount of Na ions in the ammonium fluorosilicate solution-modified nanoclustered Y molecular sieves balances the framework charge and stabilizes the sodalite cages. The lower-energy Al-O bonds in the framework are preferentially broken or semi-broken, causing some sodalite cages to distort and break, while others remain stable due to the presence of Na ions. Ultimately, dealumination allows for the formation of a certain amount of secondary mesopores while maintaining a high degree of crystallinity. Therefore, retaining an appropriate amount of Na ions in the nanoclustered Y molecular sieves is crucial for improving the framework stability during the dealumination process.

[0040] In the above modification method, in step (b), the nanoclustered Y molecular sieve is treated with ammonium fluorosilicate solution at 60°C-120°C, preferably 80°C-100°C, for 3h-5h, and the treatment times are 1-2 times to obtain the pretreated Y molecular sieve.

[0041] In the above modification method, the concentration of the ammonium fluorosilicate solution in step (b) is 0.02 mol / L-0.15 mol / L.

[0042] In the above modification method, the solid-to-liquid ratio of the nano-clustered Y molecular sieve to the ammonium fluorosilicate solution in step (b) is 1:20-50 (g:mL).

[0043] In the above modification method, the hydrothermal treatment in step (c) is a steam heat treatment: the material obtained in step (b) is contacted with steam at a temperature of 500-700°C and a pressure of 0.01-0.5 MPa for 1-4 hours. Preferably, the steam heat treatment is performed 1-2 times.

[0044] In the above modification method, the acid treatment process in step (d) is to treat the material after the hydrothermal treatment in step (c) with an acid solution at a constant temperature of 50-120° C. for 1-3 hours.

[0045] In the above modification method, the acid in step (d) is one or more of nitric acid, sulfuric acid, hydrochloric acid, citric acid and oxalic acid, and the concentration of the acid solution is 0.2-1.5 mol / L, preferably 0.5-1.0 mol / L.

[0046] In the above modification method, in step (d), the solid-to-liquid ratio of the material after hydrothermal treatment in step (c) to the acid solution is 1:6-15 (g:mL), preferably 1:8-10 (g:mL).

[0047] The present invention is further described in detail below with reference to specific examples. The examples are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following examples.

[0048] The experimental methods in the following examples, unless otherwise specified, are conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, were purchased from conventional biochemical reagent stores. In the present invention, the crystal structure and relative crystallinity of the synthesized molecular sieve were determined by XRD characterization, using the nanoclustered Y molecular sieve synthesized in Example 1 as a standard sample; the average particle size of the molecular sieve was determined by a laser particle size analyzer, and the average particle size of the nanocrystals constituting the clusters was determined by the empirical formula d=4061 / S ext Determine (where d is the particle size in nm, S exteral is the external specific surface area of ​​the cluster, in m 2 / g); the elemental compositions of the molecular sieve and catalyst were determined by XRF characterization; pore information was obtained by nitrogen adsorption-desorption testing of Y molecular sieve using an ASAP 2420 automatic physical adsorption instrument at 77K; the acid content of the molecular sieve was determined by pyridine adsorption infrared spectroscopy; the reaction conversion was calculated using the product's actual boiling point cutoff data; the tail oil BMCI was determined using the following method: BMCI = 48640 / T + 473.7d - 456.8, where d is the density (15.6°C) and T is the average boiling point expressed in absolute temperature K.

[0049] Example 1

[0050] (1) According to the molecular sieve mother liquor molar composition of Na2O:Al2O3:SiO2:H2O=4:1:10:300, the mass ratio of carboxylated nanocellulose to silicon source (calculated by SiO2 content) is 0.03:1. Silica sol with a mass content of 30%, carboxylated nanocellulose (diameter 4-10nm, length 100-200nm), sodium hydroxide, sodium metaaluminate, and water are mixed, stirred and aged at room temperature for 24h, and then transferred into a polytetrafluoroethylene stainless steel reactor and crystallized at 100℃ for 72h. The molecular sieve solid is separated by filtration, washed with deionized water until the washing water is neutral, dried at 100℃ for 24h, and calcined at 550℃ for 3h to obtain nanoclustered Y molecular sieve.

[0051] (2) The nanoclustered Y molecular sieve was mixed with a 1.0 mol / L ammonium nitrate solution at a solid-liquid ratio of 1:10, and ammonium ion exchange was performed at 80°C for 2 h. This process was repeated once to obtain a desodiumized Y molecular sieve with a Na2O content of 3.2% by mass.

[0052] (3) The desodiumized Y molecular sieve was mixed with a 0.05 mol / L ammonium fluorosilicate solution at a solid-liquid ratio of 1:30 and treated at 90°C for 4 h to obtain a pretreated Y molecular sieve with a silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) of 9.5.

[0053] (4) The pretreated Y molecular sieve is contacted with water vapor at a temperature of 600°C and a pressure of 0.1 MPa for 2 hours to obtain a dealuminated Y molecular sieve.

[0054] (5) The dealuminated Y molecular sieve was mixed with a 0.5 mol / L nitric acid solution at a solid-liquid ratio of 1:10 and treated at 80°C for 2 h to obtain a modified nanoclustered Y molecular sieve. The total pore volume of the modified nanoclustered Y molecular sieve was 0.54 cm 3 / g, the mesopore volume accounts for 42.2% of the total pore volume, of which the mesopore volume of 3nm-6nm accounts for 22% of the total mesopore volume, and the mesopore volume of 6nm-25nm accounts for 78% of the total mesopore volume; the specific surface area of ​​the modified nanocluster Y molecular sieve is 810m 2 / g; using unmodified nanocluster Y molecular sieve as a standard sample, the relative crystallinity of the modified nanocluster Y molecular sieve is 98%; the silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) of the modified nanocluster Y molecular sieve is 17.1; based on weight, the Na2O mass content in the modified nanocluster Y molecular sieve is 0.11%, and the pyridine infrared acid content is 0.79 mmol / g; in addition, the modified nanocluster Y molecular sieve in this embodiment presents a nanocluster morphology, an average particle size of 1100 nm, and the average size of the nanocrystals constituting the nanocluster Y molecular sieve is 40 nm.

[0055] (6) Modified nano-clustered Y-type molecular sieve, γ-alumina (specific surface area 460m 2 / g, pore volume 1.2cm 3 / g), MoO3 powder and nickel nitrate are mixed in a molecular sieve: alumina: NiO: MoO3 dry basis mass ratio of 50:30:5:15, and then a 15% concentration of nitric acid solution is added to the mixture to prepare a catalyst slurry with a solid content of 50%, which is then kneaded and extruded into strips.

[0056] (7) The formed catalyst was dried at a constant temperature of 120°C for 3 h and then calcined at 500°C for 3 h in an air atmosphere to obtain a hydrocracking catalyst.

[0057] The hydrocracking catalyst provided in this embodiment contains, based on its weight, 50% modified nanoclustered Y molecular sieve, 30% alumina, 5% NiO, and 15% MoO3, and is numbered C-1.

[0058] Example 2

[0059] (1) According to the molecular sieve mother liquor molar composition of Na2O:Al2O3:SiO2:H2O=3:1:8:150, the mass ratio of carboxylated nanocellulose to silicon source (calculated by SiO2 content) is 0.01:1, and 30% by mass silica sol, carboxylated nanocellulose (diameter 4-10nm, length 100-200nm), sodium hydroxide, sodium aluminate, and water are mixed, stirred and aged at room temperature for 24h, and then transferred into a polytetrafluoroethylene stainless steel reactor and crystallized at 90℃ for 48h. The molecular sieve solid is separated by filtration, washed with deionized water until the washing water is neutral, dried at 100℃ for 24h, and calcined at 550℃ for 3h to obtain nanoclustered Y molecular sieve.

[0060] (2) The nanoclustered Y molecular sieve was mixed with a 1.0 mol / L ammonium nitrate solution at a solid-liquid ratio of 1:10, and ammonium ion exchange was performed at 80°C for 2 h. This process was repeated once to obtain a desodiumized Y molecular sieve with a Na2O content of 2.9% by mass.

[0061] (3) The desodiumized Y molecular sieve was mixed with a 0.03 mol / L ammonium fluorosilicate solution at a solid-liquid ratio of 1:30, and treated at 100°C for 2 h. The process was repeated once to obtain a pretreated Y molecular sieve with a silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) of 13.0.

[0062] (4) The pretreated Y molecular sieve was contacted with water vapor at a temperature of 550° C. and a pressure of 0.05 MPa for 1 h to obtain a dealuminated Y molecular sieve.

[0063] (5) The dealuminated Y molecular sieve was mixed with a 2 mol / L hydrochloric acid solution at a solid-liquid ratio of 1:15 and treated at 120°C for 3 h to obtain a modified nanoclustered Y molecular sieve. The total pore volume of the modified nanoclustered Y molecular sieve was 0.53 cm 3 / g, the mesopore volume accounts for 39.2% of the total pore volume, of which the mesopore volume of 3nm-6nm accounts for 20% of the total mesopore volume, and the mesopore volume of 6nm-25nm accounts for 80% of the total mesopore volume; the specific surface area of ​​the modified nanocluster Y molecular sieve is 840m 2 / g; using unmodified nanoclustered Y molecular sieve as a standard sample, the modified nanoclustered Y molecular sieve had a relative crystallinity of 100%; the modified nanoclustered Y molecular sieve had a silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of 18.7; and the modified nanoclustered Y molecular sieve had a Na2O mass content of 0.15% and a pyridinic acid content of 0.74 mmol / g, based on weight. Furthermore, the modified nanoclustered Y molecular sieve in this example exhibited a clustered morphology, an average particle size of 900 nm, and an average size of the nanocrystals comprising the nanoclustered Y molecular sieve of 55 nm.

[0064] (6) Modified nano-clustered Y-type molecular sieve, γ-alumina (specific surface area 400m 2 / g, pore volume 0.9cm 3 / g), MoO3 powder and nickel nitrate are mixed in a molecular sieve: alumina: NiO: MoO3 dry basis mass ratio of 40:38:5:17, and then a 10% concentration of nitric acid solution is added to the mixture to prepare a catalyst slurry with a solid content of 60%, which is then kneaded and extruded into strips.

[0065] (7) The formed catalyst was dried at a constant temperature of 120°C for 3 h and then calcined at 500°C for 3 h in an air atmosphere to obtain a hydrocracking catalyst.

[0066] The hydrocracking catalyst provided in this embodiment contains, based on its weight, 40% of modified nano-clustered Y molecular sieve, 38% of alumina, 5% of NiO, and 17% of MoO3, and is numbered C-2.

[0067] Example 3

[0068] (1) According to the molecular sieve mother liquor molar composition of Na2O:Al2O3:SiO2:H2O=6:1:15:500, the mass ratio of carboxylated nanocellulose to silicon source (calculated by SiO2 content) is 0.05:1. Silica sol with a mass content of 30%, carboxylated nanocellulose (diameter 4-10nm, length 100-200nm), sodium hydroxide, sodium aluminate, and water are mixed, stirred and aged at room temperature for 24h, and then transferred into a polytetrafluoroethylene stainless steel reactor and crystallized at 110℃ for 120h. The molecular sieve solid is separated by filtration, washed with deionized water until the washing water is neutral, dried at 100℃ for 24h, and calcined at 550℃ for 3h to obtain nanoclustered Y molecular sieve.

[0069] (2) The nanoclustered Y molecular sieve was mixed with a 1 mol / L ammonium nitrate solution at a solid-liquid ratio of 1:10, and ammonium ion exchange was performed at 80°C for 2 h to obtain a desodiumized Y molecular sieve with a Na2O content of 4.1% by mass.

[0070] (3) The desodiumized Y molecular sieve was mixed with a 0.12 mol / L ammonium fluorosilicate solution at a solid-liquid ratio of 1:50 and treated at 90°C for 5 h to obtain a pretreated Y molecular sieve with a silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) of 12.8.

[0071] (4) The pretreated Y molecular sieve was contacted with water vapor at a temperature of 650°C and a pressure of 0.2 MPa for 5 h to obtain a dealuminated Y molecular sieve.

[0072] (5) The dealuminated Y molecular sieve was mixed with a 1 mol / L hydrochloric acid solution at a solid-liquid ratio of 1:10 and treated at 80°C for 3 h to obtain a modified nanoclustered Y molecular sieve. The total pore volume of the modified nanoclustered Y molecular sieve was 0.56 cm 3 / g, the mesopore volume accounts for 44.0% of the total pore volume, of which the mesopore volume of 3nm-6nm accounts for 13% of the total mesopore volume, and the mesopore volume of 6nm-25nm accounts for 87% of the total mesopore volume; the specific surface area of ​​the modified nanocluster Y molecular sieve is 793m 2 / g; using unmodified nanoclustered Y molecular sieve as a standard sample, the modified nanoclustered Y molecular sieve had a relative crystallinity of 95%; the modified nanoclustered Y molecular sieve had a silicon-to-aluminum ratio (SiO2 / Al2O3 molar ratio) of 26.0; and the modified nanoclustered Y molecular sieve had a Na2O mass content of 0.17% and a pyridinic acid content of 0.53 mmol / g, based on weight. Furthermore, the modified nanoclustered Y molecular sieve in this example exhibited a clustered morphology, an average particle size of 1600 nm, and an average size of the nanocrystals comprising the nanoclustered Y molecular sieve of 68 nm.

[0073] (6) Modified nano-clustered Y-type molecular sieve, γ-alumina (specific surface area 425m 2 / g, pore volume 1.0cm 3 / g), ammonium metatungstate and nickel nitrate are mixed in a molecular sieve:alumina:NiO:WO3 dry basis mass ratio of 30:45:7:18, and then a 20% concentration of nitric acid solution is added to the mixture to prepare a catalyst slurry with a solid content of 40%, which is then kneaded and extruded into strips.

[0074] (7) The formed catalyst was dried at a constant temperature of 100°C for 5 h and then calcined at 500°C for 3 h in an air atmosphere to obtain a hydrocracking catalyst.

[0075] The hydrocracking catalyst provided in this embodiment contains, based on its weight, 30% of modified nano-clustered Y molecular sieve, 45% of alumina, 7% of NiO, and 18% of WO3, and is numbered C-3.

[0076] Example 4

[0077] The preparation process for the nanoclustered Y molecular sieve-based hydrocracking catalyst was the same as in Example 1, except that the nanoclustered Y molecular sieve synthesized in Example 1 was replaced with the nanoclustered Y molecular sieve prepared using the method described in Example 1 of CN108862309A. The hydrocracking catalyst provided in this example contained, by weight, 50% modified nanoclustered Y molecular sieve, 30% alumina, 5% NiO, and 15% MoO3, and was designated C-4.

[0078] Comparative Example 1

[0079] The molecular sieve modification process and catalyst preparation steps were the same as in Example 1, except that the nanoclustered Y molecular sieve in Example 1 was replaced with a Y molecular sieve prepared by the method of Example 4 in the specification of patent CN104743572A. The hydrocracking catalyst provided in this comparative example contained, by weight, 50% modified Y molecular sieve, 30% alumina, 5% NiO, and 15% MoO3, and was designated D-1.

[0080] Comparative Example 2

[0081] The molecular sieve modification process and catalyst preparation steps were the same as in Example 2, except that the nanoclustered Y molecular sieve in Example 2 was replaced with a Y molecular sieve prepared using the method described in Example 4 of patent CN104743572A. The hydrocracking catalyst provided in this comparative example contained, by weight, 40% modified Y molecular sieve, 38% alumina, 5% NiO, and 17% MoO3, and was designated D-2.

[0082] Comparative Example 3

[0083] The molecular sieve modification process and catalyst preparation steps were the same as in Example 3, except that the nanoclustered Y molecular sieve in Example 3 was replaced with a Y molecular sieve prepared using the method described in Example 4 of patent CN104743572A. The hydrocracking catalyst provided in this comparative example contained, by weight, 30% modified Y molecular sieve, 45% alumina, 7% NiO, and 18% WO3, and was designated D-3.

[0084] Evaluation Example 1

[0085] Catalysts C-1 to C-4 prepared in the Examples and catalysts D-1 to D-3 prepared in the Comparative Examples were subjected to pressurized wax oil hydrocracking evaluation tests in a small fixed-bed apparatus. The feedstock properties are shown in Table 1. The evaluation apparatus adopted a single-stage series single-pass process flow, with the first reactor loaded with a conventional refined catalyst and the second reactor loaded with a hydrocracking catalyst. The specific process conditions and evaluation results are shown in Table 2.

[0086] The properties of the crude oil used in the hydrocracking evaluation experiment are shown in Table 1:

[0087] Table 1 Properties of crude oil

[0088]

[0089]

[0090] Table 2 Evaluation results of the hydrocracking catalyst of the present invention

[0091]

[0092] It can be seen from the results in Table 2 that the hydrocracking catalyst provided by the embodiment of the present invention has the advantages of high reaction activity, high product liquid yield, low hydrogen consumption, and low BMCI value of the tail oil product.

Claims

1. A hydrocracking catalyst, characterized in that: The hydrocracking catalyst comprises, based on its weight, 10%-50% of a modified Y molecular sieve, 30%-70% of a binder, and 20%-35% of a hydrogenation active metal calculated as a metal oxide; wherein the modified Y molecular sieve is a modified nanoclustered Y molecular sieve; the hydrogenation active metal is selected from metals of Group VIII and / or Group VIB, wherein the Group VIII metal is Ni and / or Co, and the Group VIB metal is W and / or Mo, and the content of the Group VIII metal calculated as a metal oxide is 5%-10%, and the content of the Group VIB metal calculated as a metal oxide is 15%-25%, based on the weight of the catalyst; the average particle size of the modified nanoclustered Y molecular sieve is 500nm-2000nm, preferably 1000nm-1500nm; the pore volume of the modified nanoclustered Y molecular sieve is 0.4cm 3 / g-0.7cm 3 / g, preferably 0.5cm 3 / g-0.6cm 3 / g, the mesopore volume accounts for 30%-55%, preferably 40%-50%, the mesopore volume of 6nm-25nm accounts for more than 60% of the total mesopore volume, preferably 65%-95%, and more preferably 70%-90%; the specific surface area of ​​the modified nano-clustered Y molecular sieve is 700m 2 / g-900m 2 / g, preferably 750m 2 / g-850m 2 / g.

2. The catalyst according to claim 1, characterized in that: The mesopore distribution in the modified nano-clustered Y molecular sieve is 3-25 nm, wherein the volume of mesopores with a size of 3 nm to less than 6 nm accounts for 5%-30% of the total mesopore volume, preferably 10%-25%.

3. The catalyst according to claim 1, characterized in that: The average particle size of the nanoparticles constituting the modified nanoclustered Y molecular sieve clusters is about 30 nm to 100 nm, preferably 40 nm to 70 nm.

4. The catalyst according to claim 1, characterized in that: The modified nano-clustered Y molecular sieve has a relative crystallinity of 90%-110%, preferably 95%-105%.

5. The catalyst according to claim 1, characterized in that: The silicon-aluminum ratio of the modified nano-clustered Y molecular sieve is 8-50, preferably 10-30, calculated as a SiO2 / Al2O3 molar ratio.

6. The catalyst according to claim 1, characterized in that: The modified nano-clustered Y molecular sieve has a pyridine infrared acid content of 0.3 mmol / g to 1.2 mmol / g, preferably 0.5 mmol / g to 1 mmol / g.

7. The method for preparing the hydrocracking catalyst according to any one of claims 1 to 6, characterized in that: Includes the following: (1) mixing the modified nano-clustered Y-type molecular sieve, a binder, and a hydrogenation active metal in a certain proportion, and then adding a peptizing agent (e.g., nitric acid solution) to the mixture to prepare a slurry, kneading, and extruding; (2) Drying and calcining the extrudate obtained in step (1) to obtain a hydrocracking catalyst. The pyridine infrared ion content of the clustered Y molecular sieve is 0.3 mmol / g-1.2 mmol / g, preferably 0.5 mmol / g-1 mmol / g.

8. The method according to claim 7, wherein: The binder in step (1) is γ-alumina, characterized in that the specific surface area is 200m 2 / g-600m 2 / g, preferably 300m 2 / g-500m 2 / g; pore volume 0.5cm 3 / g-1.5cm 3 / g, preferably 0.8cm 3 / g-1.2cm 3 / g.

9. The method according to claim 7, wherein: In step (2), the extruded product is dried at 80-120° C. for 6-12 hours and then calcined at 400-500° C. for 1-5 hours.

10. A hydrocracking method, characterized in that: The hydrocracking catalyst according to any one of claims 1 to 6 is used.

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