A silicon-modified beta zeolite molecular sieve, a hydrocatalytic diesel hydrocracking catalyst, a preparation method and application thereof

Abstract

This invention discloses a silicon-modified Beta zeolite molecular sieve, a hydrocracking catalyst for diesel fuel, its preparation method, and its applications. The silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 80-300, preferably 100-200, and an acid content of 0.05-0.35 mmol / g, preferably 0.1-0.3 mmol / g. This invention uses the silicon-modified Beta zeolite molecular sieve as a partially active component in the acid-functionalized cracking of the catalyst, which can effectively improve the yield of light aromatics and xylene products in conventional Beta zeolite molecular sieve-based hydrocracking catalysts for diesel fuel.

Description

Technical Field

[0001] This invention relates to the field of hydrocracking technology, specifically to a silicon-modified Beta zeolite molecular sieve, a catalytic diesel hydrocracking catalyst, its preparation method, and its application. Background Technology

[0002] The important method for utilizing catalytic diesel is to convert it into high-value-added light oil products through hydrocracking units after hydrorefining.

[0003] For example, Chinese patent CN1955262A discloses a two-stage hydrocracking method that can produce high-aromatic, high-potential-value heavy naphtha from inferior catalytic diesel. CN101724454A and CN101917971A disclose technologies for converting catalytic diesel into high-octane gasoline blending components. In these methods, modified Y-type zeolite molecular sieves are used as the active cracking component in the hydrocracking catalyst. After the catalyst stabilizes, the single-pass conversion rate reaches 30-60%, and the cracking products have a high non-aromatic content and a low C6-10 light aromatic content. Recent studies have found that Beta zeolite molecular sieves exhibit good ring-opening and selective cracking capabilities in the hydrocracking reaction of catalytic diesel. Chinese patent CN105435836A discloses a hydrocracking catalyst and its preparation and application, using ZSM-5 and Beta zeolite molecular sieves as the active cracking components, exhibiting a high tetrahydronaphthalene conversion rate. Chinese patent CN114433211A discloses a chemical-type hydrocracking catalyst, its preparation method, and its application. It selects Beta zeolite and layered MWW-type zeolite molecular sieves as the cracking active components, effectively improving the single-pass conversion rate of the feedstock and the yield of light aromatics. Chinese patent CN112570016A discloses a nitrogen-resistant aromatics-type hydrocracking catalyst, its preparation method, and its application. It selects Beta zeolite molecular sieves with high acid strength as the cracking active component, achieving high feedstock conversion rate and long-term stability.

[0004] Although Beta zeolite molecular sieves have good ring-opening cracking ability and can improve catalyst conversion when used as cracking active components in catalytic diesel hydrocracking catalysts, conventional Beta zeolite molecular sieves have poor selectivity for light aromatics and xylene. Therefore, there is a need for a modified Beta zeolite molecular sieve with better selectivity for light aromatics and xylene, resulting in higher yields of light aromatics and xylene in the product. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a silicon-modified Beta zeolite molecular sieve, a catalytic diesel hydrocracking catalyst, its preparation method, and its application. The catalytic diesel hydrocracking catalyst can be applied to the hydrocracking reaction of hydrotreated catalytic diesel, realizing the lightening process of converting hydrotreated catalytic diesel into high-value-added chemical products such as light aromatics, ethylene cracking feedstock, and high-octane gasoline blending components.

[0006] One objective of this invention is to provide a silicon-modified Beta zeolite molecular sieve with a silicon-aluminum oxide molecular ratio of 80-300, preferably 100-200, and an acidity of 0.05-0.35 mmol / g, preferably 0.1-0.3 mmol / g.

[0007] In a preferred embodiment of the present invention,

[0008] The silicon-aluminum oxide molecular sieve used for the modification of the silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 10-200, preferably 20-100, more preferably 35-80, and an acid content of 0.2-2.0 mmol / g, preferably 0.2-1.0 mmol / g. The raw material Beta zeolite molecular sieve can be obtained commercially or prepared using any preparation method in the art, preferably Chinese Patent CN110668459A, which is incorporated herein by reference in its entirety; and / or,

[0009] The modifier used in the silicon-modified Beta zeolite molecular sieve is silicone oil; the silicone oil preferably includes at least one of methyl silicone oil (dimethyl silicone oil), ethyl silicone oil, phenyl silicone oil, amino silicone oil, methyl hydrogen silicone oil, methyl phenyl silicone oil, methyl ethoxy silicone oil, methyl vinyl silicone oil, methyl hydroxy silicone oil, ethyl hydrogen silicone oil, hydroxy hydrogen silicone oil, and polyether-modified silicone oil, more preferably at least one of methyl silicone oil and ethyl silicone oil, and most preferably methyl silicone oil. Preferably, the viscosity of the silicone oil is 10-500 mPa·s, more preferably 10-200 mPa·s.

[0010] In a preferred embodiment of the present invention,

[0011] The silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio increased by 50-100 compared to the unmodified raw Beta zeolite molecular sieve; and / or, the acid content of the silicon-modified Beta zeolite molecular sieve is reduced by 0.1-1.8 mmol / g compared to the unmodified raw Beta zeolite molecular sieve, preferably reduced by 0.1-0.8 mmol / g.

[0012] In a preferred embodiment of the present invention,

[0013] The silicon-modified Beta zeolite molecular sieve is prepared by a method including mixing and reacting components containing the unmodified raw material Beta zeolite molecular sieve and a modifier, followed by filtration, drying, and calcination.

[0014] The second objective of this invention is to provide a method for preparing silicon-modified Beta zeolite molecular sieves, which is one of the objectives of this invention. The method includes mixing and reacting components, including the unmodified raw material Beta zeolite molecular sieve and a modifier, followed by filtration, drying, and calcination. The modifier is silicone oil.

[0015] In a preferred embodiment of the present invention,

[0016] The volume ratio of the unmodified Beta zeolite molecular sieve to the modifier is 1:(5-20), preferably 1:(5-10); and / or,

[0017] The reaction temperature is 20-40℃, preferably 25-35℃; and / or,

[0018] The reaction time can be any duration greater than 1 hour, preferably 2-24 hours, more preferably 3-7 hours, and even more preferably 4-6 hours; and / or,

[0019] The drying temperature is 100-120℃, and the drying time is 8-16 hours; and / or,

[0020] The roasting temperature is 450-550℃, and the roasting time is 3-6 hours. Preferably, the roasting is carried out in an air atmosphere.

[0021] In a preferred embodiment of the present invention,

[0022] The reaction is carried out under stirring, preferably at a stirring rate of 400-600 rpm.

[0023] The present invention can be specifically implemented using the following methods:

[0024] Using silicone oil as a modifier, the components, including the unmodified Beta zeolite molecular sieve and silicone oil, are mixed, stirred and reacted for a certain time, filtered, dried in an oven at 100-120℃ for 8-16 hours, and then placed in a muffle furnace and calcined at 450-550℃ in air atmosphere for 3-6 hours.

[0025] A third objective of this invention is to provide a catalytic diesel hydrocracking catalyst, comprising the following components:

[0026] a) Beta zeolite molecular sieve II;

[0027] b) Silicon-modified Beta zeolite molecular sieve;

[0028] c) Active metal components;

[0029] d) Adhesive;

[0030] Preferably, the silicon-modified Beta zeolite molecular sieve described above is at least one of the silicon-modified Beta zeolite molecular sieve according to one objective of the present invention and the silicon-modified Beta zeolite molecular sieve prepared by the preparation method according to another objective of the present invention.

[0031] In a preferred embodiment of the present invention,

[0032] The Beta zeolite molecular sieve II may be the same as or different from the raw material Beta zeolite molecular sieve before modification with silicon-modified Beta zeolite molecular sieve. The silicon-aluminum oxide molecular ratio of the Beta zeolite molecular sieve II is 10-200, preferably 20-100, and more preferably 50-80.

[0033] In a preferred embodiment of the present invention,

[0034] The active metal component includes at least one of Group VIII metals and Group VIII metal sulfides, and at least one of Group VIB metal oxides and Group VIB metal sulfides, preferably including at least one of Group VIII metal-Group VIB metal oxides, Group VIII metal sulfides-Group VIB metal sulfides, and Group VIII metal sulfides-Group VIB metal oxides-Group VIB metal sulfides.

[0035] In a preferred embodiment of the present invention,

[0036] The Group VIII metals include at least one of platinum, palladium, ruthenium, cobalt, nickel, and iridium; and / or,

[0037] The group VIB metal oxide includes at least one of molybdenum and tungsten oxides; preferably at least one of molybdenum dioxide, molybdenum trioxide, tungsten dioxide, and tungsten trioxide; and / or,

[0038] The group VIII metal sulfides include at least one of iron, cobalt, and nickel sulfides; and / or,

[0039] The group VIB metal sulfides include at least one of molybdenum disulfide and tungsten disulfide.

[0040] In a preferred embodiment of the present invention,

[0041] The binder includes at least one of alumina, silicon oxide, silicon oxide-alumina composite, and amorphous aluminum silicate.

[0042] In a preferred embodiment of the present invention,

[0043] By weight percentage,

[0044] The total mass of the zeolite molecular sieve accounts for 5-80 wt% of the catalyst mass, preferably 20-75 wt%, more preferably 30-70 wt%, wherein the silicon-modified Beta zeolite molecular sieve accounts for 1-99 wt% of the total mass of the zeolite molecular sieve, preferably 5-70 wt%, more preferably 20-50 wt%; and / or,

[0045] The active metal component accounts for 3-35 wt% of the catalyst mass, preferably 5-23 wt%; and / or,

[0046] The remainder is adhesive.

[0047] In a preferred embodiment of the present invention,

[0048] By weight percentage,

[0049] The group VIII metal and / or group VIII metal sulfides constitute 0.01-10 wt% of the catalyst mass, preferably 0.5-8 wt%; and / or,

[0050] The group VIB metal oxides and / or sulfides account for 3-25 wt% of the catalyst mass, preferably 5-15 wt%.

[0051] The fourth objective of this invention is to provide a method for preparing a catalytic diesel hydrocracking catalyst, which is also the objective of this invention. The method includes loading the metal active component onto a support containing Beta zeolite molecular sieve II, silicon-modified Beta zeolite molecular sieve, and a binder, and then reducing and / or sulfiding the support to obtain the catalytic diesel hydrocracking catalyst.

[0052] The catalytic diesel hydrocracking catalyst of the present invention can be prepared using any method of catalyst preparation in the art, without particular limitation. For example, the preparation of the catalyst of the present invention may include the steps of forming a catalyst support containing the Beta zeolite molecular sieve II, silicon-modified Beta zeolite molecular sieve and binder, loading the metal active component compound, drying and calcining to obtain a catalyst precursor, and reducing and / or sulfiding the catalyst precursor. The support forming method may employ methods commonly used in the art, such as extrusion, ball rolling, or oil column forming; the loading of the metal active component may employ methods commonly used in the art, such as co-precipitation, co-gelling, kneading, ion exchange, or impregnation of the metal active component with the catalyst support. Preferably, it may include the following specific steps:

[0053] 1) The catalyst support is prepared by mixing, extruding, and drying the components including the Beta zeolite molecular sieve II, the silicon-modified Beta zeolite molecular sieve and the binder, and then calcining them in air at 500-600℃.

[0054] 2) Prepare an aqueous solution of a metal compound, including at least one of the group VIII metal compounds and at least one of the group VIB metal compounds; impregnate the catalyst support obtained above by an equal-volume impregnation method, dry it, and then calcine it in an air atmosphere at 450-580°C to obtain a catalyst precursor.

[0055] 3) The obtained catalyst precursor was reduced under hydrogen conditions at 400-500℃ to obtain the catalyst;

[0056] Alternatively, the obtained catalyst precursor can be sulfurized under sulfurization conditions of 280-360℃ to obtain the catalyst;

[0057] Alternatively, the obtained catalyst precursor can be reduced with hydrogen and then sulfided to obtain the catalyst.

[0058] The fifth objective of this invention is to provide the application of the catalytic diesel hydrocracking catalyst of objective three of this invention or the catalytic diesel hydrocracking catalyst obtained by the preparation method of objective four of this invention in the hydrocracking reaction of hydrotreated catalytic diesel, including the step of contacting the catalyst with hydrotreated catalytic diesel under hydrocracking conditions.

[0059] In a preferred embodiment of the present invention,

[0060] The feedstock for the catalytic diesel hydrocracking catalyst of the present invention in the hydrocracking reaction is hydrotreated catalytic diesel that has undergone hydrorefining. The catalytic diesel has a T95 of ≤360℃, preferably ≤345℃, and the hydrotreated catalytic diesel has an aromatic content of ≥70wt% and a nitrogen content of ≤20ppm.

[0061] In a preferred embodiment of the present invention,

[0062] The process conditions for the hydrocracking reaction include:

[0063] Reactor inlet temperature 280-450℃, preferably 310-430℃, more preferably 350-410℃; and / or,

[0064] Hydrogen partial pressure 5-10 MPa, preferably 5-9 MPa, more preferably 6-8 MPa; and / or,

[0065] Mass hourly space velocity (MHSV) 0.5-2.0 h -1 Preferably 0.6-1.5h -1 More preferably 0.8-1.2h -1 ; and / or,

[0066] The hydrogen-to-oil volume ratio of fresh hydrogen to hydrotreated catalytic diesel is 400-1000, preferably 500-800, more preferably 500-600; and / or,

[0067] The hydrogen-to-oil volume ratio of the mixed hydrogen to the hydrotreated catalytic diesel is 1000-5000, preferably 2000-4000, and more preferably 2000-3000.

[0068] In a preferred embodiment of the present invention,

[0069] Hydrocracking reaction products satisfy C 6-10 The component yield is ≥35wt%, preferably ≥38wt%, more preferably ≥40wt%; and / or, the xylene yield is ≥11wt%, preferably ≥12wt%, more preferably ≥13wt%.

[0070] The beneficial effects of this invention are as follows: The catalytic diesel hydrocracking catalyst of this invention can be applied to the hydrocracking reaction of hydrotreated catalytic diesel, realizing the lightening process of converting hydrotreated catalytic diesel into high-value-added chemical products such as light aromatics, ethylene cracking feedstock, and high-octane gasoline blending components. This invention uses silicon-modified Beta zeolite molecular sieves as part of the active component for acid-functionalized cracking of the catalyst, which can effectively improve the yield of light aromatics and xylene products in conventional Beta zeolite molecular sieve-based catalytic diesel hydrocracking catalysts. Detailed Implementation

[0071] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0072] All raw materials used in the embodiments of this invention are conventional commercially available raw materials.

[0073] The compositional analysis of the catalysts involved in this invention employs existing analytical methods in the art. For example, the composition of the catalysts and molecular sieves was analyzed using X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma atomic emission spectroscopy (ICP); the valence state and composition of the metals in the catalysts were determined using X-ray photoelectron spectroscopy (XPS). XRF, ICP, and XPS characterization were performed using a Rigaku ZSX100e X-ray fluorescence spectrometer and a Varian 700 X-ray fluorescence spectrometer, respectively. The measurements were performed using an ES series inductively coupled plasma atomic emission spectrometer and a PerkinElmer PHI5000CESCA X-ray photoelectron spectrometer.

[0074] In this invention, the hydrocarbon composition of hydrocracking products is determined by online gas chromatography. The chromatograph is an Agilent 7890A, equipped with an FID detector. Gas phase hydrocarbon composition is analyzed using an HP-PLOT Q capillary column, and liquid phase hydrocarbon composition is analyzed using an HP-INNOWax capillary column.

[0075] The formula for calculating the yield of hydrocarbon components is:

[0076]

[0077] (In the above formula, the content of the component in the liquid phase (gas phase) is determined by chromatography; the liquid phase yield is calculated by dividing the hourly product mass by the hourly feed rate; the gas phase yield is calculated by dividing the sum of the masses of each tail gas component by the hourly tail gas flow rate measured by a wet flow meter by the hourly feed rate.)

[0078] Example 1

[0079] The Beta zeolite molecular sieve was prepared according to Example 4 of Chinese Patent CN110668459A. The resulting Beta zeolite molecular sieve had a silica-alumina oxide molecular ratio of 38 and an acid content of 0.79 mmol / g.

[0080] Preparation of silicon-modified Beta zeolite molecular sieves:

[0081] Mix 20 ml of the above-mentioned Beta zeolite molecular sieve with 100 ml of dimethyl silicone oil (Aladdin D104762), 25 o C. Stir at 600 rpm and react for 4 hours. Filter the mixture, dry it in an oven at 120°C for 12 hours, and then calcine it in a muffle furnace at 550°C for 3 hours in air. The resulting silicon-modified Beta zeolite molecular sieve silicon-aluminum oxide has a molecular ratio of 10:2 and an acid content of 0.25 mmol / g.

[0082] Preparation of catalysts for catalytic diesel hydrocracking:

[0083] 10.0 g of silicon-modified Beta zeolite molecular sieve and 20.7 g of pseudoboehmite were mixed, extruded, dried at 90 °C, and calcined in air at 550 °C for 4 hours to obtain a catalyst support. Then, 6.24 g of nickel nitrate hexahydrate and 3.02 g of ammonium molybdate tetrahydrate were prepared into a clear solution. The catalyst support was impregnated with an equal volume of metal solution, dried at 100 °C, and calcined at 520 °C for 2 hours to obtain a catalyst precursor. The catalyst precursor was reduced at 400 °C for 4 hours in hydrogen at a flow rate of 80 ml / min to obtain a catalyst with the following composition: 3.5 wt% Ni - 5.2 wt% MoO2 - 1.0 wt% MoO3 / 25.0 wt% Beta molecular sieve - 25.0 wt% silicon-modified Beta molecular sieve - 40.3 wt% Al2O3.

[0084] Applications of catalysts:

[0085] The hydrocracking reactor was loaded with 10.0 g of CAT-1 catalyst. The properties of the hydrocracking diesel feedstock and the hydrocracking reaction conditions are shown in Table 1. The reaction results are shown in Table 2.

[0086] Table 1. Feedstock Properties and Hydrocracking Reaction Conditions

[0087]

[0088] Example 2

[0089] The Beta zeolite molecular sieve was prepared according to Example 4 of Chinese Patent CN110668459A. The resulting Beta zeolite molecular sieve had a silica-alumina oxide molecular ratio of 38 and an acid content of 0.79 mmol / g.

[0090] Preparation of silicon-modified Beta zeolite molecular sieves:

[0091] Take 20 ml of the above-mentioned Beta zeolite molecular sieve and mix it with 120 ml of ethyl silicone oil (Huaxiang Kejie, CAS: 63148-61-8), 30 o C. Stirred at 500 rpm for 6 hours, filtered, dried in an oven at 120℃ for 12 hours, and then calcined in a muffle furnace at 520℃ for 4 hours in air atmosphere. The resulting silicon-modified Beta zeolite molecular sieve silicon-aluminum oxide had a molecular ratio of 120 and an acidity of 0.22 mmol / g.

[0092] Preparation of catalysts for catalytic diesel hydrocracking:

[0093] 4.0 g of silicon-modified Beta zeolite molecular sieve, 16.0 g of Beta zeolite molecular sieve, and 21.1 g of pseudoboehmite were mixed, extruded, dried at 90 °C, and calcined in air at 550 °C for 4 hours to obtain a catalyst support. 6.24 g of nickel nitrate hexahydrate and 2.17 g of ammonium metatungstate were then prepared into a clear solution. The catalyst support was impregnated with an equal volume of metal solution, dried at 100 °C, and calcined at 520 °C for 2 hours to obtain a catalyst precursor. The catalyst precursor was reduced at 450 °C for 4 hours in hydrogen at a flow rate of 80 ml / min, and then cooled to 320 °C and injected with dimethyl disulfide for 4 hours to obtain a catalyst with the following composition: 3.5 wt% Ni - 3.3 wt% WO2 - 1.7 wt% WS2 - 0.5 wt% WO3 / 40 wt% Beta molecular sieve - 10 wt% silicon-modified Beta molecular sieve - 41.0 wt% Al2O3.

[0094] Applications of catalysts:

[0095] The hydrocracking reactor was loaded with 10.0 g of catalyst. The properties of the hydrocracking diesel feedstock and the hydrocracking reaction conditions were the same as in Example 1. The reaction results are shown in Table 2.

[0096] Example 3

[0097] The Beta zeolite molecular sieve was prepared according to Example 5 of Chinese Patent CN110668459A. The resulting Beta zeolite molecular sieve had a silica-alumina oxide molecular ratio of 75 and an acid content of 0.28 mmol / g.

[0098] Preparation of silicon-modified Beta zeolite molecular sieves:

[0099] Mix 20 ml of the above-mentioned Beta zeolite molecular sieve with 200 ml of dimethyl silicone oil (Aladdin D104762), 30 o C. Stir at 400 rpm for 5 hours, filter, dry in an oven at 100°C for 16 hours, and then calcine in a muffle furnace at 540°C for 6 hours in air atmosphere. The resulting silicon-modified Beta zeolite molecular sieve silicon-aluminum oxide has a molecular ratio of 168 and an acidity of 0.13 mmol / g.

[0100] Preparation of catalysts for catalytic diesel hydrocracking:

[0101] 8.0 g of silicon-modified Beta zeolite molecular sieve, 12.0 g of Beta zeolite molecular sieve, and 20.7 g of pseudoboehmite were mixed, extruded, dried at 90 °C, and calcined in air at 550 °C for 4 h to obtain a catalyst support. Then, 6.22 g of cobalt nitrate hexahydrate and 3 g of ammonium molybdate tetrahydrate were prepared into a clear solution. The catalyst support was impregnated with an equal volume of metal solution, dried at 100 °C, and calcined at 520 °C for 2 h to obtain a catalyst precursor. The catalyst precursor was reduced at 400 °C for 4 h in a hydrogen atmosphere at 80 ml / min. The catalyst composition was: 3.5 wt% Co - 5.2 wt% MoO2 - 1.0 wt% MoO3 / 30.0 wt% Beta molecular sieve - 20 wt% silicon-modified Beta molecular sieve - 40.3 wt% Al2O3. 3。

[0102] Applications of catalysts:

[0103] The hydrocracking reactor was loaded with 10.0 g of catalyst. The properties of the hydrocracking diesel feedstock and the hydrocracking reaction conditions are shown in Table 1. The reaction results are shown in Table 2.

[0104] Example 4

[0105] The Beta zeolite molecular sieve was prepared according to Example 5 of Chinese Patent CN110668459A. The resulting Beta zeolite molecular sieve had a silica-alumina oxide molecular ratio of 75 and an acid content of 0.28 mmol / g.

[0106] Preparation of silicon-modified Beta zeolite molecular sieves:

[0107] Mix 20 ml of the above-mentioned Beta zeolite molecular sieve with 140 ml of dimethyl silicone oil (Aladdin D104762), 35 o C. Stir at 600 rpm for 5 hours, filter, dry in an oven at 110°C for 8 hours, and then calcine in a muffle furnace at 450°C for 6 hours in air atmosphere. The resulting silicon-modified Beta zeolite molecular sieve silicon-aluminum oxide has a molecular ratio of 156 and an acidity of 0.15 mmol / g.

[0108] Preparation of catalysts for catalytic diesel hydrocracking:

[0109] 6.0 g of silicon-modified Beta zeolite molecular sieve, 14.0 g of Beta zeolite molecular sieve, and 20.7 g of pseudoboehmite were mixed, extruded, dried at 90 °C, and calcined in air at 550 °C for 4 h to obtain a catalyst support. Then, 6.24 g of nickel nitrate hexahydrate and 3.02 g of ammonium molybdate tetrahydrate were prepared into a clear solution. The catalyst support was impregnated with an equal volume of metal solution, dried at 100 °C, and calcined at 520 °C for 2 h to obtain a catalyst precursor. The catalyst precursor was reduced at 400 °C for 4 h in hydrogen at a flow rate of 80 ml / min to obtain a catalyst with the following composition: 3.5 wt% Ni - 5.2 wt% MoO2 - 1.0 wt% MoO3 / 35.0 wt% Beta molecular sieve - 15.0 wt% silicon-modified Beta molecular sieve - 40.3 wt% Al2O3.

[0110] Applications of catalysts:

[0111] The hydrocracking reactor was loaded with 10.0 g of catalyst. The properties of the hydrocracking diesel feedstock and the hydrocracking reaction conditions were the same as in Example 3. The reaction results are shown in Table 2.

[0112] Example 5

[0113] The Beta zeolite molecular sieve was prepared according to Example 4 of Chinese Patent CN110668459A. The resulting Beta zeolite molecular sieve had a silica-alumina oxide molecular ratio of 38 and an acid content of 0.79 mmol / g.

[0114] Preparation of silicon-modified Beta zeolite molecular sieves:

[0115] Take 20 ml of the above-mentioned Beta zeolite molecular sieve and mix it with 120 ml of ethyl silicone oil (Huaxiang Kejie, CAS: 63148-61-8), 30 oC. Stirred at 500 rpm for 24 hours, filtered, dried in an oven at 120℃ for 12 hours, and then calcined in a muffle furnace at 520℃ for 4 hours in air atmosphere. The resulting silicon-modified Beta zeolite molecular sieve silicon-aluminum oxide had a molecular ratio of 320 and an acidity of 0.02 mmol / g.

[0116] Preparation of catalysts for catalytic diesel hydrocracking:

[0117] 4.0 g of silicon-modified Beta zeolite molecular sieve, 16.0 g of Beta zeolite molecular sieve, and 21.1 g of pseudoboehmite were mixed, extruded, dried at 90 °C, and calcined in air at 550 °C for 4 hours to obtain a catalyst support. 6.24 g of nickel nitrate hexahydrate and 2.17 g of ammonium metatungstate were then prepared into a clear solution. The catalyst support was impregnated with an equal volume of metal solution, dried at 100 °C, and calcined at 520 °C for 2 hours to obtain a catalyst precursor. The catalyst precursor was reduced at 450 °C for 4 hours in hydrogen at a flow rate of 80 ml / min, and then cooled to 320 °C and injected with dimethyl disulfide for 4 hours to obtain a catalyst with the following composition: 3.5 wt% Ni - 3.3 wt% WO2 - 1.7 wt% WS2 - 0.5 wt% WO3 / 40 wt% Beta molecular sieve - 10 wt% silicon-modified Beta molecular sieve - 41.0 wt% Al2O3.

[0118] Applications of catalysts:

[0119] The hydrocracking reactor was loaded with 10.0 g of catalyst. The properties of the hydrocracking diesel feedstock and the hydrocracking reaction conditions were the same as in Example 1. The reaction results are shown in Table 2.

[0120] Comparative Example 1

[0121] Preparation of catalysts for catalytic diesel hydrocracking:

[0122] The specific preparation process is basically the same as in Example 1, except that silicon-modified Beta zeolite molecular sieve is not used. The Beta zeolite molecular sieve in the catalyst is entirely the Beta zeolite molecular sieve prepared according to Example 4 of Chinese Patent CN110668459A. The final catalyst composition is: 3.5wt%Ni-5.2wt%MoO2-1.0wt%MoO3 / 50.0wt%Beta molecular sieve-40.3wt%Al2O3.

[0123] Applications of catalysts:

[0124] The hydrocracking reactor was loaded with 10.0 g of catalyst. The properties of the hydrocracking diesel feedstock and the hydrocracking reaction conditions were the same as in Example 1. The reaction results are shown in Table 2.

[0125] Comparative Example 2

[0126] The preparation methods for Beta zeolite molecular sieves, silicon-modified Beta zeolite molecular sieves, and catalytic diesel hydrocracking catalysts are the same as in Example 1.

[0127] Applications of catalysts:

[0128] The hydrocracking reactor was loaded with 10.0 g of catalyst. The properties of the hydrocracking diesel feedstock and the hydrocracking reaction conditions are shown in Table 1. The reaction results are shown in Table 2.

[0129] Comparative Example 3

[0130] The Beta zeolite molecular sieve was prepared according to Example 4 of Chinese Patent CN110668459A. The resulting Beta zeolite molecular sieve had a silica-alumina oxide molecular ratio of 38 and an acid content of 0.79 mmol / g.

[0131] Preparation of silicon-modified Beta zeolite molecular sieves:

[0132] 20 ml of the above-mentioned Beta zeolite molecular sieve was mixed with 120 ml of ethyl silicone oil (Huaxiang Kejie, CAS: 63148-61-8), stirred at 30℃ and 500 rpm for 0.5 h, filtered, dried in an oven at 120℃ for 12 h, and then calcined in a muffle furnace at 520℃ for 4 h in air atmosphere. The resulting silicon-modified Beta zeolite molecular sieve had a silicon-aluminum oxide molecular ratio of 69 and an acidity of 0.31 mmol / g.

[0133] Preparation of catalysts for catalytic diesel hydrocracking:

[0134] 4.0 g of silicon-modified Beta zeolite molecular sieve, 16.0 g of Beta zeolite molecular sieve, and 21.1 g of pseudoboehmite were mixed, extruded, dried at 90 °C, and calcined in air at 550 °C for 4 hours to obtain a catalyst support. Then, 6.24 g of nickel nitrate hexahydrate and 2.17 g of ammonium metatungstate were prepared into a clear solution. The catalyst support was impregnated with an equal volume of metal solution, dried at 100 °C, and calcined at 520 °C for 4 hours to obtain a catalyst precursor. The catalyst precursor was reduced at 450 °C for 4 hours in hydrogen at a flow rate of 80 ml / min, and then cooled to 320 °C and injected with dimethyl disulfide for 4 hours to obtain a catalyst with the following composition: 3.5 wt% Ni - 3.3 wt% WO2 - 1.7 wt% WS2 - 0.5 wt% WO3 / 40 wt% Beta molecular sieve - 10 wt% silicon-modified Beta molecular sieve - 41.0 wt% Al2O3.

[0135] Applications of catalysts:

[0136] The hydrocracking reactor was loaded with 10.0 g of catalyst. The properties of the hydrocracking diesel feedstock and the hydrocracking reaction conditions were the same as in Example 1. The reaction results are shown in Table 2.

[0137] Comparative Example 4

[0138] The preparation methods for Beta zeolite molecular sieves and silicon-modified Beta zeolite molecular sieves are the same as in Example 3.

[0139] Preparation of catalysts for catalytic diesel hydrocracking:

[0140] 20.0 g of silicon-modified Beta zeolite molecular sieve and 20.7 g of pseudoboehmite were mixed, extruded, dried at 90 °C, and calcined in air at 550 °C for 4 h to obtain a catalyst support. A clear solution was prepared by mixing 6.22 g of cobalt nitrate hexahydrate and 3 g of ammonium molybdate tetrahydrate. The catalyst support was impregnated with an equal volume of molten metal solution, dried at 100 °C, and calcined at 520 °C for 2 h to obtain a catalyst precursor. The catalyst precursor was reduced at 400 °C for 4 h in a hydrogen atmosphere at 80 ml / min. The catalyst composition was: 3.5 wt% Co - 5.2 wt% MoO2 - 1.0 wt% MoO3 / 50 wt% silicon-modified Beta molecular sieve - 40.3 wt% Al2O3. 3。

[0141] Applications of catalysts:

[0142] The hydrocracking reactor was loaded with 10.0 g of catalyst. The properties of the hydrocracking diesel feedstock and the hydrocracking reaction conditions were the same as in Example 3. The reaction results are shown in Table 2.

[0143] Table 2 Hydrocarbon Yields

[0144]

[0145] As can be seen from Example 1, Comparative Example 1, and Table 2, the catalyst without silicon-modified Beta zeolite molecular sieve has a lower Cg than the catalyst prepared using partially silicon-modified Beta zeolite molecular sieve proposed in this invention. 6-10 Yields of light aromatics and xylene.

[0146] As can be seen from Example 1, Comparative Example 2, and Table 2, if the selected hydrocatalytic diesel feedstock is unsuitable, with an aromatic content ≤70wt%, it will affect product quality. 6-10 The yields of light aromatics and xylene are low.

[0147] As can be seen from Example 2, Comparative Example 3, and Table 2, a reaction time that is too short during the preparation of silicon-modified Beta zeolite molecular sieve will affect the catalyst effect, leading to C 6-10 The yields of light aromatics and xylene are low.

[0148] As can be seen from Example 3, Comparative Example 4, and Table 2, the use of silicon-modified Beta zeolite molecular sieves entirely in the preparation of catalysts leads to C 11+ Excessive levels of heavy aromatics also affect C6-10 Yields of light aromatics and xylene.

Claims

1. A hydrocracking catalyst for diesel fuel, comprising the following components: a) Beta zeolite molecular sieve II; b) Silicon-modified Beta zeolite molecular sieve; c) Active metal components; d) Adhesive; The silicon-modified Beta zeolite molecular sieves described above have a silicon-aluminum oxide molecular ratio of 80-300 and an acidity of 0.05-0.35 mmol / g.

2. The hydrocracking catalyst for diesel fuel as described in claim 1, characterized in that: The silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 100-200 and an acidity of 0.1-0.3 mmol / g.

3. The hydrocracking catalyst for diesel fuel as described in claim 1, characterized in that: The silicon-modified Beta zeolite molecular sieve before modification has a silicon-aluminum oxide molecular ratio of 10-200 and an acidity of 0.2-2.0 mmol / g; and / or, The modifier for the silicon-modified Beta zeolite molecular sieve is silicone oil.

4. The hydrocracking catalyst for diesel fuel as described in claim 3, characterized in that: The silicon-modified Beta zeolite molecular sieve before modification has a silicon-aluminum oxide molecular ratio of 20-100 and an acidity of 0.2-1.0 mmol / g; and / or, The silicone oil includes at least one of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, amino silicone oil, methyl hydrogen silicone oil, methyl phenyl silicone oil, methyl ethoxy silicone oil, methyl vinyl silicone oil, methyl hydroxy silicone oil, ethyl hydrogen silicone oil, hydroxy hydrogen silicone oil, and polyether-modified silicone oil.

5. The hydrocracking catalyst for diesel fuel as described in claim 4, characterized in that: The silicon-aluminum oxide molecular ratio of the raw material Beta zeolite molecular sieve before modification is 35-80; and / or, The silicone oil is at least one of methyl silicone oil and ethyl silicone oil.

6. The hydrocracking catalyst for diesel fuel as described in claim 5, characterized in that: The silicone oil is methyl silicone oil.

7. The hydrocracking catalyst for diesel hydrocracking as described in claim 1, characterized in that: The silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio increased by 50-100 compared to the unmodified raw Beta zeolite molecular sieve; and / or, the acid content of the silicon-modified Beta zeolite molecular sieve is reduced by 0.1-1.8 mmol / g compared to the unmodified raw Beta zeolite molecular sieve.

8. The hydrocracking catalyst for diesel fuel as described in claim 7, characterized in that: The silicon-modified Beta zeolite molecular sieve has a reduced acid content of 0.1-0.8 mmol / g compared to the unmodified raw Beta zeolite molecular sieve.

9. The hydrocracking catalyst for diesel fuel as described in claim 1, characterized in that: The silicon-modified Beta zeolite molecular sieve is prepared by a method including mixing and reacting components containing the unmodified raw material Beta zeolite molecular sieve and a modifier, followed by filtration, drying, and calcination; the modifier is silicone oil.

10. The hydrocracking catalyst for diesel fuel as described in claim 9, characterized in that: The volume ratio of the unmodified Beta zeolite molecular sieve to the modifier is 1:(5-20); and / or, The reaction temperature is 20-40℃; and / or, The reaction time is greater than 1 hour; and / or, The drying temperature is 100-120℃, and the drying time is 8-16 hours; and / or, The roasting temperature is 450-550℃, and the roasting time is 3-6 hours.

11. The hydrocracking catalyst for diesel fuel as described in claim 10, characterized in that: The volume ratio of the unmodified Beta zeolite molecular sieve to the modifier is 1:(5-10); and / or, The reaction temperature is 25-35℃; and / or, The reaction time is 2-24 hours; and / or, The roasting is carried out in an air atmosphere.

12. The hydrocracking catalyst for diesel fuel as described in claim 11, characterized in that: The reaction time is 3-7 hours.

13. The hydrocracking catalyst for diesel fuel as described in claim 12, characterized in that: The reaction time is 4-6 hours.

14. The hydrocracking catalyst for diesel fuel as described in claim 9, characterized in that: The reaction was carried out under stirring.

15. The hydrocracking catalyst for diesel fuel as described in claim 14, characterized in that: The stirring speed is 400-600 rpm.

16. The hydrocracking catalyst for diesel fuel as described in claim 1, characterized in that: The Beta zeolite molecular sieve II may be the same as or different from the raw material Beta zeolite molecular sieve before modification of silicon-modified Beta zeolite molecular sieve, and the silicon-aluminum oxide molecular ratio of the Beta zeolite molecular sieve II is 10-200.

17. The hydrocracking catalyst for diesel fuel as described in claim 16, characterized in that: The silicon-aluminum oxide molecular ratio of the Beta zeolite molecular sieve II is 20-100.

18. The hydrocracking catalyst for diesel fuel as described in claim 17, characterized in that: The silicon-aluminum oxide molecular ratio of the Beta zeolite molecular sieve II is 50-80.

19. The hydrocracking catalyst for diesel fuel as described in claim 1, characterized in that: The active metal component includes at least one of Group VIII metals and Group VIII metal sulfides, and at least one of Group VIB metal oxides and Group VIB metal sulfides.

20. The hydrocracking catalyst for diesel fuel as described in claim 19, characterized in that: The active metal component includes at least one of Group VIII metal-Group VIB metal oxide, Group VIII metal sulfide-Group VIB metal sulfide, and Group VIII metal sulfide-Group VIB metal oxide-Group VIB metal sulfide.

21. The hydrocracking catalyst for diesel fuel as described in claim 19, characterized in that: The Group VIII metals include at least one of platinum, palladium, ruthenium, cobalt, nickel, and iridium; and / or, The group VIB metal oxides include at least one of the oxides of molybdenum and tungsten; and / or, The group VIII metal sulfides include at least one of iron, cobalt, and nickel sulfides; and / or, The group VIB metal sulfides include at least one of molybdenum disulfide and tungsten disulfide.

22. The hydrocracking catalyst for diesel fuel as described in claim 21, characterized in that: The group VIB metal oxide is at least one of molybdenum dioxide, molybdenum trioxide, tungsten dioxide, and tungsten trioxide.

23. The hydrocracking catalyst for diesel fuel as described in claim 1, characterized in that: The binder includes at least one of alumina, silicon oxide, silicon oxide-alumina composite, and amorphous aluminum silicate.

24. The hydrocracking catalyst for diesel fuel as described in any one of claims 1-23, characterized in that: By weight percentage, The total mass of the zeolite molecular sieve accounts for 5-80 wt% of the catalyst mass, wherein the silicon-modified Beta zeolite molecular sieve accounts for 1-99 wt% of the total mass of the zeolite molecular sieve; and / or, The active metal component accounts for 3-35 wt% of the catalyst mass.

25. The hydrocracking catalyst for diesel fuel as described in claim 24, characterized in that: By weight percentage, The total mass of the zeolite molecular sieve accounts for 20-75 wt% of the catalyst mass, of which the silicon-modified Beta zeolite molecular sieve accounts for 5-70 wt% of the total mass of the zeolite molecular sieve; and / or, The active metal component accounts for 5-23 wt% of the catalyst mass.

26. The hydrocracking catalyst for diesel fuel as described in claim 25, characterized in that: By weight percentage, The total mass of the zeolite molecular sieve accounts for 30-70 wt% of the catalyst mass, of which the silicon-modified Beta zeolite molecular sieve accounts for 20-50 wt% of the total mass of the zeolite molecular sieve.

27. The hydrocracking catalyst for diesel fuel as described in claim 19, characterized in that: By weight percentage, The group VIII metal and / or group VIII metal sulfides constitute 0.01-10 wt% of the catalyst mass; and / or, The group VIB metal oxides and / or sulfides account for 3-25 wt% of the catalyst mass.

28. The hydrocracking catalyst for diesel fuel as described in claim 27, characterized in that: By weight percentage, The group VIII metal and / or group VIII metal sulfides constitute 0.5-8 wt% of the catalyst mass; and / or, The group VIB metal oxides and / or sulfides account for 5-15 wt% of the catalyst mass.

29. A method for preparing a hydrocracking catalyst for diesel fuel as described in any one of claims 1-28, comprising loading the metal active component onto a support containing Beta zeolite molecular sieve II, silicon-modified Beta zeolite molecular sieve and a binder, and then reducing and / or sulfiding the support to obtain the hydrocracking catalyst for diesel fuel.

30. The application of the hydrocracking catalyst for hydrotreated diesel fuel according to any one of claims 1-28 or the hydrocracking catalyst for hydrotreated diesel fuel obtained by the preparation method according to claim 29 in the hydrocracking reaction of hydrotreated diesel fuel, comprising the step of contacting the catalyst with hydrotreated catalytic diesel fuel under hydrocracking conditions; wherein the hydrotreated catalytic diesel fuel is hydrotreated catalytic diesel fuel that has undergone hydrorefining treatment; wherein the catalytic diesel fuel has a T95 ≤ 360°C, and the hydrotreated catalytic diesel fuel obtained after hydrorefining has an aromatic hydrocarbon content ≥ 70 wt% and a nitrogen content ≤ 20 ppm.

31. The application as described in claim 30, characterized in that: The catalytic diesel oil has a temperature of T95 ≤ 345℃.

32. The application as described in claim 30, characterized in that: The process conditions for the hydrocracking reaction include: Reactor inlet temperature 280-450℃; and / or, Hydrogen partial pressure 5-10 MPa; and / or, Mass hourly space velocity (MHSV) 0.5-2.0 h -1 ; and / or, The hydrogen-to-oil volume ratio of fresh hydrogen to hydrotreated catalytic diesel is 400-1000; and / or, The hydrogen-to-oil volume ratio of the mixed hydrogen to the hydrotreated catalytic diesel is 1000-5000.

33. The application as described in claim 32, characterized in that: The process conditions for the hydrocracking reaction include: Reactor inlet temperature 310-430℃; and / or, Hydrogen partial pressure 5-9 MPa; and / or, Mass hourly space velocity (MHSV) 0.6-1.5 h -1 ; and / or, The hydrogen-to-oil volume ratio of fresh hydrogen to hydrotreated catalytic diesel is 500-800; and / or, The hydrogen-to-oil volume ratio of the mixed hydrogen to the hydrotreated catalytic diesel is 2000-4000.

34. The application as described in claim 33, characterized in that: The process conditions for the hydrocracking reaction include: Reactor inlet temperature 350-410℃; and / or, Hydrogen partial pressure 6-8 MPa; and / or, Mass hourly space velocity (MHSV) 0.8-1.2 h -1 ; and / or, The hydrogen-to-oil volume ratio of fresh hydrogen to hydrotreated catalytic diesel is 500-600; and / or, The hydrogen-to-oil volume ratio of the mixed hydrogen to the hydrotreated catalytic diesel is 2000-3000.

35. The application as described in claim 30, characterized in that: Hydrocracking reaction products satisfy C 6-10 The component yield is ≥35 wt%; and / or, the xylene yield is ≥11 wt%.

36. The application as described in claim 35, characterized in that: Hydrocracking reaction products satisfy C 6-10 The component yield is ≥38 wt%; and / or, the xylene yield is ≥12 wt%.

37. The application as described in claim 36, characterized in that: Hydrocracking reaction products satisfy C 6-10 The component yield is ≥40 wt%; and / or, the xylene yield is ≥13 wt%.

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