Silicon-modified Beta zeolite molecular sieve, catalyst for catalyzing diesel hydrocracking, preparation method and application

Abstract

The invention discloses a silicon-modified Beta zeolite molecular sieve, a catalyst for catalyzing diesel hydrocracking, a preparation method and an application. According to the silicon modified Beta zeolite molecular sieve, the molecular ratio of silicon oxide to aluminum oxide is 80 to 300, preferably 100 to 200, and the acid content is 0.05 to 0.35 mmol / g, preferably 0.1 to 0.3 mmol / g. According to the invention, the silicon-modified Beta zeolite molecular sieve is used as a part of active component for acid functional cracking of the catalyst, so that the yield of light aromatic hydrocarbon and xylene products of a conventional Beta zeolite molecular sieve-based diesel oil hydrocracking catalyst can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of hydrocracking, and in particular to a silicon-modified Beta zeolite molecular sieve, a catalytic diesel hydrocracking catalyst, and a preparation method and application thereof. Background Art

[0002] In recent years, with the improvement of catalytic cracking unit processing capacity, the output of catalytic diesel has increased year by year. However, the growth of diesel market demand has stagnated. In addition, the domestic environmental protection requirements for oil products have been improved. The National VI standard was implemented in 2019. Refining companies have an oversupply of inferior diesel such as catalytic diesel. How to use it efficiently has become a bottleneck restricting the processing capacity and efficiency improvement of my country's refining companies. Converting catalytic diesel into light oil products with high added value through hydrocracking units after hydrofining is an important means of utilizing catalytic diesel.

[0003] For example, Chinese patent CN1955262A discloses a two-stage hydrocracking method, which can produce high aromatic potential heavy naphtha from inferior catalytic diesel. CN101724454A and CN101917971A disclose the technology of converting catalytic diesel into high-octane gasoline blending components. In the method, the hydrocracking catalyst uses a modified Y-type zeolite molecular sieve as a cracking active component. After the catalyst runs stably, the single-pass conversion rate reaches 30-60%, and the non-aromatic content in the cracking product is high, and the C6-10 light aromatic content is low. In recent years, studies have found that Beta zeolite molecular sieves have shown good ring opening and selective cracking capabilities in catalytic diesel hydrocracking reactions. Chinese patent CN105435836A discloses a hydrocracking catalyst and its preparation and application, using ZSM-5 and Beta zeolite molecular sieves as cracking active components, with a high tetralin conversion rate. Chinese patent CN114433211A discloses a chemical hydrocracking catalyst, its preparation method and application, and selects Beta zeolite and layered MWW zeolite molecular sieve as cracking active components, effectively improving the single-pass conversion rate of raw materials and the yield of light aromatics. Chinese patent CN112570016A discloses a nitrogen-resistant aromatic hydrocracking catalyst, its preparation method and application, and selects Beta zeolite molecular sieve with high strong acid content as cracking active component, which can achieve high conversion rate and long-term stability of raw materials.

[0004] Although Beta zeolite molecular sieve has good ring-opening cracking ability and can improve the catalyst conversion rate as a cracking active component of catalytic diesel hydrocracking catalyst, conventional Beta zeolite molecular sieve has poor selectivity for light aromatics and xylenes. Therefore, there is a need for a modified Beta zeolite molecular sieve with better selectivity for light aromatics and xylenes and higher yield of light aromatics and xylenes in the product. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a silicon-modified Beta zeolite molecular sieve, a catalytic diesel hydrocracking catalyst, a preparation method and an application thereof. The catalytic diesel hydrocracking catalyst can be applied to the hydrocracking reaction of hydrocatalytic diesel, realizing the lightening process of converting hydrocatalytic diesel into high value-added chemical products such as light aromatics, ethylene cracking raw materials and high-octane gasoline blending components.

[0006] One of the purposes of the present invention is to provide a silicon-modified Beta zeolite molecular sieve, wherein the silicon-aluminum oxide molecular ratio is 80-300, preferably 100-200, and the acid content is 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-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 before modification can be obtained from the market or prepared by any preparation method in the prior art, and the preparation method is preferably referred to Chinese patent CN110668459A, which is fully introduced here; 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, methylphenyl silicone oil, methylethoxy silicone oil, methylvinyl silicone oil, methylhydroxy 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 10-500mPa.s, and more preferably 10-200mPa.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 raw Beta zeolite molecular sieve before modification; and / or the acid content of the silicon-modified Beta zeolite molecular sieve is reduced by 0.1-1.8 mmol / g, preferably by 0.1-0.8 mmol / g, compared to the raw Beta zeolite molecular sieve before modification.

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

[0013] The silicon-modified Beta zeolite molecular sieve is prepared by a method comprising the steps of mixing components including the raw material Beta zeolite molecular sieve before modification and a modifier, filtering and drying, and then calcining.

[0014] The second object of the present invention is to provide a method for preparing silicon-modified Beta zeolite molecular sieve according to one of the objects of the present invention, comprising the steps of mixing and reacting the components including the raw Beta zeolite molecular sieve before modification and the modifier, filtering and drying, and then calcining; the modifier is silicone oil.

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

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

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

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

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

[0020] The calcination temperature is 450-550° C., and the calcination time is 3-6 hours. Preferably, the calcination is performed 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 specifically adopt the following method:

[0024] With silicone oil as a modifier, the components including the raw material Beta zeolite molecular sieve before modification and silicone oil are mixed, stirred for reaction for a certain period of time and then filtered, dried in an oven at 100-120°C for 8-16 hours, placed in a muffle furnace, and calcined at 450-550°C for 3-6 hours in an air atmosphere.

[0025] The third object of the present 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) metal active components;

[0029] d) binder;

[0030] Preferably, the silicon-modified Beta zeolite molecular sieve is at least one of the silicon-modified Beta zeolite molecular sieve of one of the purposes of the present invention and the silicon-modified Beta zeolite molecular sieve prepared by the preparation method of the second purpose of the present invention.

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

[0032] The Beta zeolite molecular sieve II is the same as or different from the raw material Beta zeolite molecular sieve before modification of the 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 metal active 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, and preferably 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.

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

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

[0037] The VIB group 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 sulfide comprises at least one of sulfides of iron, cobalt and nickel; and / or,

[0039] The VIB group metal sulfide includes 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 aluminum oxide, silicon oxide, silicon oxide-aluminum oxide composite, and amorphous silicon aluminum.

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

[0043] In terms of mass percentage,

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

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

[0046] The balance is binder.

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

[0048] In terms of mass percentage,

[0049] The Group VIII metal and / or Group VIII metal sulfide accounts for 0.01-10 wt %, preferably 0.5-8 wt % of the catalyst mass; and / or,

[0050] The VIB Group metal oxide and / or sulfide accounts for 3-25 wt %, preferably 5-15 wt % of the catalyst mass.

[0051] The fourth object of the present invention is to provide a method for preparing a catalytic diesel hydrocracking catalyst according to the third object of the present invention, comprising loading the metal active component on a carrier comprising Beta zeolite molecular sieve II, silicon-modified Beta zeolite molecular sieve and a binder, and then reducing and / or sulfurizing to obtain the catalytic diesel hydrocracking catalyst.

[0052] The catalytic diesel hydrocracking catalyst described in the present invention can be prepared by any method for preparing catalysts in the art, without special limitation. For example, the preparation of the catalyst described in the present invention can include the steps of molding a catalyst carrier comprising the Beta zeolite molecular sieve II, silicon-modified Beta zeolite molecular sieve and a binder, drying and calcining the catalyst precursor after loading the metal active component compound, and reducing and / or sulfurizing the catalyst precursor. The carrier molding method can be carried out by the usual methods of extrusion, rolling ball or oil column molding in the art; the loading of the metal active component can be carried out by the usual methods of co-precipitation, co-gelation, kneading, ion exchange or impregnation of the metal active component and the catalyst carrier in the art. Preferably, the following specific steps can be included:

[0053] 1) kneading and extruding the components including the Beta zeolite molecular sieve II, the silicon-modified Beta zeolite molecular sieve and the binder, drying and then calcining in an air atmosphere at 500-600° C. to obtain a catalyst carrier;

[0054] 2) preparing a metal compound aqueous solution with metal components including at least one of the Group VIII metal compounds and at least one of the Group VIB metal compounds; impregnating the above obtained catalyst carrier by an equal volume impregnation method, and calcining in an air atmosphere at 450-580° C. after drying to obtain a catalyst precursor;

[0055] 3) reducing the obtained catalyst precursor under hydrogen conditions at 400-500° C. to obtain the catalyst;

[0056] Alternatively, the obtained catalyst precursor is sulfurized under a sulfurization condition of 280-360° C. to obtain the catalyst;

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

[0058] The fifth object of the present invention is to provide a catalytic diesel hydrocracking catalyst according to the third object of the present invention or a catalytic diesel hydrocracking catalyst obtained by the preparation method according to the fourth object of the present invention in a hydrocatalytic diesel hydrocracking reaction, comprising the step of contacting the catalyst with hydrocatalytic diesel under hydrocracking conditions.

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

[0060] The feedstock oil suitable for the catalytic diesel hydrocracking catalyst in the hydrocracking reaction of the present invention is hydrogenated catalytic diesel that has been treated with hydrofining. The catalytic diesel has a T95 of ≤360°C, preferably ≤345°C, and the aromatic content of the hydrogenated catalytic diesel obtained after hydrofining is ≥70wt%, and the nitrogen content is ≤20ppm.

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

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

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

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

[0065] Mass airspeed 0.5-2.0h -1 , preferably 0.6-1.5h -1 , more preferably 0.8-1.2h -1 and / or,

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

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

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

[0069] The 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] Beneficial effects of the present invention: The catalytic diesel hydrocracking catalyst of the present invention can be applied to the hydrocracking reaction of hydrocatalytic diesel, and realizes the lightening process of hydrocatalytic diesel into high value-added chemical products such as light aromatics, ethylene cracking raw materials and high-octane gasoline blending components. The present invention uses silicon-modified Beta zeolite molecular sieve as part of the active component of the catalyst acid functional cracking, which can effectively improve the yield of light aromatics and xylene products of conventional Beta zeolite molecular sieve-based catalytic diesel hydrocracking catalysts. DETAILED DESCRIPTION

[0071] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0072] The raw materials used in the examples of the present invention are all conventional commercially available raw materials.

[0073] The composition analysis of the catalyst involved in the present invention adopts the existing analysis methods in the art. For example, the composition of the catalyst and molecular sieve is analyzed by X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma emission spectroscopy (ICP); the metal valence and composition in the catalyst are determined by X-ray photoelectron spectroscopy (XPS). XRF, ICP and XPS characterization are respectively determined by Rigaku ZSX100e X-ray fluorescence spectrometer, Varian 700-ES series inductively coupled plasma emission spectrometer and PerkinElmer PHI5000CESCA X-ray photoelectron spectrometer.

[0074] In the present invention, the hydrocarbon composition of the hydrocracking product is determined by online gas chromatography. The chromatographic model is Agilent 7890A, equipped with a FID detector, the gas phase hydrocarbon composition is analyzed by HP-PLOT Q capillary chromatographic column, and the liquid phase hydrocarbon composition is analyzed by HP-INNOWax capillary chromatographic column.

[0075] The calculation formula for hydrocarbon component yield is:

[0076] Yield of a hydrocarbon component

[0077] =Content of the component in the liquid phase × yield of the liquid phase + content of the component in the gas phase

[0078] ×Gas phase yield

[0079] (In the above formula, the content of the component in the liquid phase (gas phase) is measured by chromatography; the liquid phase yield is calculated by dividing the weighed product mass per hour by the hourly feed amount; the gas phase yield is calculated by dividing the sum of the mass of each tail gas component by the hourly tail gas flow measured by the wet flow meter by the hourly feed amount.)

[0080] Example 1

[0081] The preparation method of Beta zeolite molecular sieve refers to Example 4 of Chinese patent CN110668459A. The obtained Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 38 and an acid content of 0.79 mmol / g.

[0082] Preparation of silicon-modified Beta zeolite molecular sieve:

[0083] Take 20ml of the above Beta zeolite molecular sieve and mix it with 100ml of dimethyl silicone oil (Aladdin D104762), stir at 25℃, 600rpm, react for 4h, filter, dry in an oven at 120℃ for 12h, put it in a muffle furnace, and calcine at 550℃ for 3h in air atmosphere. The obtained silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 102 and an acid content of 0.25mmol / g.

[0084] Preparation of catalytic diesel hydrocracking catalyst:

[0085] 10.0g silicon-modified Beta zeolite molecular sieve, 10.0g Beta zeolite molecular sieve and 20.7g pseudo-boehmite were kneaded and extruded, and then dried at 90°C and calcined at 550°C in air atmosphere for 4 hours to obtain a catalyst carrier. Then 6.24g nickel nitrate hexahydrate and 3.02g ammonium molybdate tetrahydrate were prepared into a clear solution, and the catalyst carrier was impregnated with an equal volume of metal solution, dried at 100°C and calcined at 520°C for 2h to obtain a catalyst precursor. The catalyst precursor was reduced at 400°C for 4h in a hydrogen flow rate of 80ml / min to obtain a catalyst composition of: 3.5wt% Ni-5.2wt% MoO2-1.0wt% MoO3 / 25.0wt% Beta molecular sieve-25.0wt% silicon-modified Beta molecular sieve-40.3wt% Al2O3.

[0086] Application of catalyst:

[0087] The hydrocracking reactor was loaded with 10.0 g of CAT-1 catalyst, and the properties of the hydrocatalytic diesel feedstock used and the hydrocracking reaction conditions were shown in Table 1. The reaction results are shown in Table 2.

[0088] Table 1 Raw material properties and hydrocracking reaction conditions

[0089] Example 1 Example 3 Comparative Example 2 Catalytic diesel T95(℃) 330 340 310 Hydrogenation catalytic diesel aromatic content (%) 76 82 65 Hydrogenation catalytic diesel nitrogen (ppm) 7.0 12.0 6.0 Hydrogen partial pressure (Mpa) 7.0 7.5 7.0 Inlet temperature(℃) 370 380 370 Fresh Hydrogen Hydrogen Oil Volume Ratio 540 540 540 Mixed hydrogen oil volume ratio 2000 2000 2000 <![CDATA[Mass hourly space velocity (h -1 )]]> 1.0 1.0 1.0

[0090] Example 2

[0091] The preparation method of Beta zeolite molecular sieve refers to Example 4 of Chinese patent CN110668459A. The obtained Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 38 and an acid content of 0.79 mmol / g.

[0092] Preparation of silicon-modified Beta zeolite molecular sieve:

[0093] Take 20ml of the above Beta zeolite molecular sieve and mix it with 120ml of ethyl silicone oil (Huaxiang Kejie, CAS: 63148-61-8), stir at 30℃, 500rpm, react for 6h, filter, dry in an oven at 120℃ for 12h, put it in a muffle furnace, and calcine at 520℃ for 4h in air atmosphere. The obtained silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 120 and an acid content of 0.22mmol / g.

[0094] Preparation of catalytic diesel hydrocracking catalyst:

[0095] 4.0g silicon-modified Beta zeolite molecular sieve, 16.0g Beta zeolite molecular sieve and 21.1g pseudo-boehmite were kneaded and extruded, and then dried at 90°C and calcined at 550°C in air atmosphere for 4 hours to obtain a catalyst carrier. Then 6.24g nickel nitrate hexahydrate and 2.17g ammonium metatungstate were prepared into a clear solution, and the catalyst carrier was impregnated with an equal volume of metal solution, dried at 100°C, and calcined at 520°C for 2h to obtain a catalyst precursor. The catalyst precursor was reduced at 450°C for 4h in a hydrogen flow rate of 80ml / min, then cooled to 320°C and injected with dimethyl disulfide for 4h to obtain a catalyst composition of: 3.5wt% Ni-3.3wt% WO2-1.7wt% WS2-0.5wt% WO3 / 40wt% Beta molecular sieve-10wt% silicon-modified Beta molecular sieve-41.0wt% Al2O3.

[0096] Application of catalyst:

[0097] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock used and the hydrocracking reaction conditions were the same as those in Example 1. The reaction results are shown in Table 2.

[0098] Example 3

[0099] The preparation method of Beta zeolite molecular sieve refers to Example 5 of Chinese patent CN110668459A. The obtained Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 75 and an acid content of 0.28 mmol / g.

[0100] Preparation of silicon-modified Beta zeolite molecular sieve:

[0101] Take 20 ml of the above Beta zeolite molecular sieve and mix it with 200 ml of dimethyl silicone oil (Aladdin D104762), stir at 30°C and 400 rpm, react for 5 hours, filter, dry in an oven at 100°C for 16 hours, put it in a muffle furnace, and calcine at 540°C for 6 hours in an air atmosphere. The obtained silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 168 and an acid content of 0.13 mmol / g.

[0102] Preparation of catalytic diesel hydrocracking catalyst:

[0103] 8.0g of silicon-modified Beta zeolite molecular sieve, 12.0g of Beta zeolite molecular sieve and 20.7g of pseudo-boehmite were kneaded and extruded, dried at 90°C and calcined in air atmosphere at 550°C for 4h to obtain a catalyst carrier. Then 6.22g of cobalt nitrate hexahydrate and 3g of ammonium molybdate tetrahydrate were prepared into a clear solution, and the catalyst carrier was impregnated with an equal volume of metal solution, dried at 100°C and calcined at 520°C for 2h to obtain a catalyst precursor. The catalyst precursor was reduced at 400°C in a hydrogen atmosphere of 80ml / min for 4h, and the catalyst composition was: 3.5wt% Co-5.2wt% MoO2-1.0wt% MoO3 / 30.0wt% Beta molecular sieve-20wt% silicon-modified Beta molecular sieve-40.3wt% Al2O3.

[0104] Application of catalyst:

[0105] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock used and the hydrocracking reaction conditions were shown in Table 1. The reaction results are shown in Table 2.

[0106] Example 4

[0107] The preparation method of Beta zeolite molecular sieve refers to Example 5 of Chinese patent CN110668459A. The obtained Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 75 and an acid content of 0.28 mmol / g.

[0108] Preparation of silicon-modified Beta zeolite molecular sieve:

[0109] Take 20ml of the above Beta zeolite molecular sieve and mix it with 140ml of dimethyl silicone oil (Aladdin D104762), stir at 35℃, 600rpm, react for 5h, filter, dry in an oven at 110℃ for 8h, put it in a muffle furnace, and calcine at 450℃ for 6h in air atmosphere. The obtained silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 156 and an acid content of 0.15mmol / g.

[0110] Preparation of catalytic diesel hydrocracking catalyst:

[0111] 6.0g of silicon-modified Beta zeolite molecular sieve, 14.0g of Beta zeolite molecular sieve and 20.7g of pseudo-boehmite were kneaded and extruded, dried at 90°C and calcined in air atmosphere at 550°C for 4h to obtain a catalyst carrier. Then 6.24g of nickel nitrate hexahydrate and 3.02g of ammonium molybdate tetrahydrate were prepared into a clear solution, and the catalyst carrier was impregnated with an equal volume of metal solution, dried at 100°C and calcined at 520°C for 2h to obtain a catalyst precursor. The catalyst precursor was reduced at 400°C for 4h in a hydrogen flow rate of 80ml / min to obtain a catalyst composition of: 3.5wt%Ni-5.2wt%MoO2-1.0wt%MoO3 / 35.0wt%Beta molecular sieve-15.0wt%silicon-modified Beta molecular sieve-40.3wt%Al2O3.

[0112] Application of catalyst:

[0113] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock used and the hydrocracking reaction conditions were the same as those in Example 3. The reaction results are shown in Table 2.

[0114] Example 5

[0115] The preparation method of Beta zeolite molecular sieve refers to Example 4 of Chinese patent CN110668459A. The obtained Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 38 and an acid content of 0.79 mmol / g.

[0116] Preparation of silicon-modified Beta zeolite molecular sieve:

[0117] Take 20ml of the above Beta zeolite molecular sieve and mix it with 120ml of ethyl silicone oil (Huaxiang Kejie, CAS: 63148-61-8), stir at 30℃, 500rpm, react for 24h, filter, dry in an oven at 120℃ for 12h, put it in a muffle furnace, and calcine at 520℃ for 4h in air atmosphere. The obtained silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 320 and an acid content of 0.02mmol / g.

[0118] Preparation of catalytic diesel hydrocracking catalyst:

[0119] 4.0g silicon-modified Beta zeolite molecular sieve, 16.0g Beta zeolite molecular sieve and 21.1g pseudo-boehmite were kneaded and extruded, and then dried at 90°C and calcined at 550°C in air atmosphere for 4 hours to obtain a catalyst carrier. Then 6.24g nickel nitrate hexahydrate and 2.17g ammonium metatungstate were prepared into a clear solution, and the catalyst carrier was impregnated with an equal volume of metal solution, dried at 100°C, and calcined at 520°C for 2h to obtain a catalyst precursor. The catalyst precursor was reduced at 450°C for 4h in a hydrogen flow rate of 80ml / min, then cooled to 320°C and injected with dimethyl disulfide for 4h to obtain a catalyst composition of: 3.5wt% Ni-3.3wt% WO2-1.7wt% WS2-0.5wt% WO3 / 40wt% Beta molecular sieve-10wt% silicon-modified Beta molecular sieve-41.0wt% Al2O3.

[0120] Application of catalyst:

[0121] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock used and the hydrocracking reaction conditions were the same as those in Example 1. The reaction results are shown in Table 2.

[0122] Comparative Example 1

[0123] Preparation of catalytic diesel hydrocracking catalyst:

[0124] The specific preparation process is basically the same as that of Example 1, except that silicon-modified Beta zeolite molecular sieve is not used, and the Beta zeolite molecular sieve in the catalyst is all Beta zeolite molecular sieve prepared with reference 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.

[0125] Application of catalyst:

[0126] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock used and the hydrocracking reaction conditions were the same as those in Example 1. The reaction results are shown in Table 2.

[0127] Comparative Example 2

[0128] The preparation methods of Beta zeolite molecular sieve, silicon-modified Beta zeolite molecular sieve and catalytic diesel hydrocracking catalyst are the same as those in Example 1.

[0129] Application of catalyst:

[0130] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock used and the hydrocracking reaction conditions were shown in Table 1. The reaction results are shown in Table 2.

[0131] Comparative Example 3

[0132] The preparation method of Beta zeolite molecular sieve refers to Example 4 of Chinese patent CN110668459A. The obtained Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 38 and an acid content of 0.79 mmol / g.

[0133] Preparation of silicon-modified Beta zeolite molecular sieve:

[0134] Take 20ml of the above Beta zeolite molecular sieve and mix it with 120ml of ethyl silicone oil (Huaxiang Kejie, CAS: 63148-61-8), stir at 30℃, 500rpm, react for 0.5h, filter, dry in an oven at 120℃ for 12h, put it in a muffle furnace, and calcine at 520℃ for 4h in air atmosphere. The obtained silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio of 69 and an acid content of 0.31mmol / g.

[0135] Preparation of catalytic diesel hydrocracking catalyst:

[0136] 4.0g silicon-modified Beta zeolite molecular sieve, 16.0g Beta zeolite molecular sieve and 21.1g pseudo-boehmite were kneaded and extruded, and then dried at 90°C and calcined at 550°C in air atmosphere for 4 hours to obtain a catalyst carrier. Then 6.24g nickel nitrate hexahydrate and 2.17g ammonium metatungstate were prepared into a clear solution, and the catalyst carrier was impregnated with an equal volume of metal solution, dried at 100°C, and calcined at 520°C for 4h to obtain a catalyst precursor. The catalyst precursor was reduced at 450°C for 4h in a hydrogen flow rate of 80ml / min, then cooled to 320°C and injected with dimethyl disulfide for 4h to obtain a catalyst composition of: 3.5wt% Ni-3.3wt% WO2-1.7wt% WS2-0.5wt% WO3 / 40wt% Beta molecular sieve-10wt% silicon-modified Beta molecular sieve-41.0wt% Al2O3.

[0137] Application of catalyst:

[0138] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock used and the hydrocracking reaction conditions were the same as those in Example 1. The reaction results are shown in Table 2.

[0139] Comparative Example 4

[0140] The preparation methods of Beta zeolite molecular sieve and silicon-modified Beta zeolite molecular sieve are the same as those in Example 3.

[0141] Preparation of catalytic diesel hydrocracking catalyst:

[0142] 20.0g of silicon-modified Beta zeolite molecular sieve and 20.7g of pseudo-boehmite were kneaded and extruded, dried at 90℃ and calcined in air atmosphere at 550℃ for 4h to obtain a catalyst carrier. Then 6.22g of cobalt nitrate hexahydrate and 3g of ammonium molybdate tetrahydrate were prepared into a clear solution, and the catalyst carrier was impregnated with an equal volume of metal solution, dried at 100℃ and calcined at 520℃ for 2h to obtain a catalyst precursor. The catalyst precursor was reduced at 400℃ for 4h in a hydrogen atmosphere of 80ml / min, and the catalyst composition was: 3.5wt% Co-5.2wt% MoO2-1.0wt% MoO3 / 50wt% silicon-modified Beta molecular sieve-40.3wt% Al2O3.

[0143] Application of catalyst:

[0144] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock used and the hydrocracking reaction conditions were the same as those in Example 3. The reaction results are shown in Table 2.

[0145] Table 2 Product hydrocarbon yield

[0146]

[0147] It can be seen from Example 1, Comparative Example 1 and Table 2 that the catalyst prepared without using silicon-modified Beta zeolite molecular sieve has a lower C 6-10 Yield of light aromatics and xylenes.

[0148] It can be seen from Example 1, Comparative Example 2 and Table 2 that if the selected hydrogenation catalytic diesel raw material is not suitable and the aromatic content is ≤70wt%, the product quality will be affected. 6-10 The yields of light aromatics and xylenes are low.

[0149] It can be seen from Example 2, Comparative Example 3 and Table 2 that the reaction time of silicon-modified Beta zeolite molecular sieve in the preparation process is too short, which will affect the catalyst effect and lead to C 6-10 The yields of light aromatics and xylenes are low.

[0150] It can be seen from Example 3, Comparative Example 4 and Table 2 that using all silicon-modified Beta zeolite molecular sieves to prepare the catalyst will result in C 11+ Heavy aromatics are too high, which also affects C 6-10 Yield of light aromatics and xylenes.

Claims

1. A silicon-modified Beta zeolite molecular sieve, wherein the molecular ratio of silicon to aluminum oxide is 80-300, preferably 100-200, and the acid content is 0.05-0.35 mmol / g, preferably 0.1-0.3 mmol / g.

2. The silicon-modified Beta zeolite molecular sieve according to claim 1, characterized in that: 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 before modification; and / or The modifier of the silicon-modified Beta zeolite molecular sieve is silicone oil; the silicone oil preferably 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, more preferably at least one of methyl silicone oil and ethyl silicone oil, and most preferably methyl silicone oil.

3. The silicon-modified Beta zeolite molecular sieve according to any one of claims 1 to 2, characterized in that: The silicon-modified Beta zeolite molecular sieve has a silicon-aluminum oxide molecular ratio increased by 50-100 compared to the raw Beta zeolite molecular sieve before modification; and / or the acid content of the silicon-modified Beta zeolite molecular sieve is reduced by 0.1-1.8 mmol / g, preferably by 0.1-0.8 mmol / g, compared to the raw Beta zeolite molecular sieve before modification.

4. The silicon-modified Beta zeolite molecular sieve according to claim 1, characterized in that: The silicon-modified Beta zeolite molecular sieve is obtained by a preparation method comprising the steps of mixing components including the raw material Beta zeolite molecular sieve before modification and a modifier, filtering and drying, and then calcining.

5. A method for preparing a silicon-modified Beta zeolite molecular sieve as claimed in any one of claims 1 to 4, comprising the steps of mixing components including the raw Beta zeolite molecular sieve before modification and a modifier, filtering and drying, and then calcining; the modifier is silicone oil.

6. The method for preparing the silicon-modified Beta zeolite molecular sieve according to claim 5, characterized in that: The volume ratio of the raw material Beta zeolite molecular sieve before modification to the modifier is 1:(5-20), preferably 1:(5-10); and / or, The reaction temperature is 20-40°C, preferably 25-35°C; and / or, The reaction time is greater than 1 hour, preferably 2-24 hours, more preferably 3-7 hours, and further preferably 4-6 hours; and / or, The drying temperature is 100-120°C and the drying time is 8-16h; and / or, The calcination temperature is 450-550° C., and the calcination time is 3-6 hours. Preferably, the calcination is performed in an air atmosphere.

7. The method for preparing the silicon-modified Beta zeolite molecular sieve according to claim 5, characterized in that: The reaction is carried out under stirring, preferably at a stirring rate of 400-600 rpm.

8. A catalytic diesel hydrocracking catalyst comprising the following components: a) Beta zeolite molecular sieve II; b) silicon-modified Beta zeolite molecular sieve; c) metal active components; d) binder; Preferably, the silicon-modified Beta zeolite molecular sieve is at least one of the silicon-modified Beta zeolite molecular sieve according to any one of claims 1 to 4 and the silicon-modified Beta zeolite molecular sieve prepared according to any one of claims 5 to 7.

9. The catalytic diesel hydrocracking catalyst as claimed in claim 8, characterized in that: The Beta zeolite molecular sieve II is the same as or different from the raw material Beta zeolite molecular sieve before modification of the 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.

10. The catalytic diesel hydrocracking catalyst according to claim 8, characterized in that: The metal active 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, and preferably 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.

11. The catalytic diesel hydrocracking catalyst according to claim 10, characterized in that: The Group VIII metal includes at least one of platinum, palladium, ruthenium, cobalt, nickel and iridium; and / or, The VIB group 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, The Group VIII metal sulfide comprises at least one of sulfides of iron, cobalt and nickel; and / or, The VIB group metal sulfide includes at least one of molybdenum disulfide and tungsten disulfide.

12. The catalytic diesel hydrocracking catalyst according to claim 8, characterized in that: The binder includes at least one of aluminum oxide, silicon oxide, silicon oxide-aluminum oxide composite, and amorphous silicon aluminum.

13. The catalytic diesel hydrocracking catalyst according to any one of claims 8 to 12, characterized in that: In terms of mass percentage, The total mass of the zeolite molecular sieve accounts for 5-80wt% of the mass of the catalyst, preferably 20-75wt%, more preferably 30-70wt%, wherein the silicon-modified Beta zeolite molecular sieve accounts for 1-99wt%, preferably 5-70wt%, more preferably 20-50wt% of the total mass of the zeolite molecular sieve; and / or, The metal active component accounts for 3-35 wt% of the catalyst mass, preferably 5-23 wt%.

14. The catalytic diesel hydrocracking catalyst according to claim 10, characterized in that: In terms of mass percentage, The Group VIII metal and / or Group VIII metal sulfide accounts for 0.01-10 wt %, preferably 0.5-8 wt % of the catalyst mass; and / or, The VIB Group metal oxide and / or sulfide accounts for 3-25 wt %, preferably 5-15 wt % of the catalyst mass.

15. A method for preparing a catalytic diesel hydrocracking catalyst as claimed in any one of claims 8 to 14, comprising loading the metal active component on a carrier comprising Beta zeolite molecular sieve II, silicon-modified Beta zeolite molecular sieve and a binder, and then reducing and / or sulfurizing to obtain the catalytic diesel hydrocracking catalyst.

16. Use of the catalytic diesel hydrocracking catalyst according to any one of claims 8 to 14 or the catalytic diesel hydrocracking catalyst obtained by the preparation method according to claim 15 in a hydrocracking reaction of hydrogenated catalytic diesel, comprising the step of contacting the catalyst with hydrogenated catalytic diesel under hydrocracking conditions.

17. The use according to claim 16, characterized in that: The catalytic diesel has a T95 of ≤360°C, preferably ≤345°C, and the hydrogenated catalytic diesel obtained after hydrogenation refining has an aromatic content of ≥70wt% and a nitrogen content of ≤20ppm.

18. The use according to claim 16, characterized in that: The process conditions of the hydrocracking reaction include: Reactor inlet temperature 280-450°C, preferably 310-430°C, more preferably 350-410°C; and / or, Hydrogen partial pressure 5-10 MPa, preferably 5-9 MPa, more preferably 6-8 MPa; and / or, Mass airspeed 0.5-2.0h -1 , preferably 0.6-1.5h -1 , more preferably 0.8-1.2h -1 and / or, The volume ratio of fresh hydrogen to hydrogenated catalytic diesel is 400-1000, preferably 500-800, more preferably 500-600; and / or, The volume ratio of hydrogen to oil of the mixed hydrogen and hydrogenated catalytic diesel is 1000-5000, preferably 2000-4000, more preferably 2000-3000.

19. The use according to claim 16, characterized in that: The 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%.

Images