Catalyst for catalyzing diesel oil hydrocracking and preparation method and application thereof

Abstract

The invention discloses a catalyst for catalyzing diesel hydrocracking and a preparation method and application thereof. The catalyst for catalyzing diesel hydrocracking comprises the following components: a) a Beta zeolite molecular sieve; b) a metal active component; c) a binder; the content of the chiral polymorph A in the Beta zeolite molecular sieve is 46 to 70 weight percent, preferably 50 to 70 weight percent, and more preferably 50 to 65 weight percent. The Beta zeolite molecular sieve with excessive chiral polymorph A is used as the catalyst for catalyzing diesel hydrocracking of an acid functional cracking active component, so that the long-period stability of the conventional Beta zeolite molecular sieve-based catalyst can be effectively improved, and the catalyst can keep high conversion per pass in a relatively long operation time.

Description

Technical Field

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

[0002] As an important by-product of the catalytic cracking unit, catalytic diesel has the characteristics of high total aromatics content, high sulfur and nitrogen content and low cetane number, and is not suitable for processing into automotive diesel. In recent years, with the improvement of the processing capacity of the catalytic cracking unit, 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 enterprises 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 enterprises.

[0003] At present, it is an important means to utilize catalytic diesel to convert it into light oil products with high added value through a hydrocracking unit after hydrofining. For example, Chinese patent CN1955262A discloses a two-stage hydrocracking method, which can produce high aromatic heavy naphtha from inferior catalytic diesel. CN101724454A and CN101917971A disclose technologies for 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%, the non-aromatic content in the cracking product is high, and C 6-10 The content of light aromatics is relatively low.

[0004] 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 and its preparation method and application, selecting Beta zeolite and layered MWW zeolite molecular sieves 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 and its preparation method and application, selecting Beta zeolite molecular sieves with high strong acid content as cracking active components, which can achieve high conversion rate and long-term stability of raw materials.

[0005] Beta zeolite molecular sieve has good ring-opening and selective cracking capabilities. As the cracking active component of catalytic diesel hydrocracking catalyst, it can improve the catalyst's single-pass conversion rate and light aromatics selectivity. However, the hydrogenated catalytic diesel after hydrorefining usually still contains a nitrogen content of several ppm to tens of ppm. The weak nitrogen resistance of conventional Beta zeolite molecular sieve makes it impossible for the catalyst to stably maintain a high catalytic activity and conversion rate, resulting in weak raw material adaptability, poor anti-fluctuation ability and long-term stability of the catalyst. This weakness seriously affects the practical application of Beta zeolite molecular sieve in catalytic diesel hydrocracking. Summary of the invention

[0006] In order to solve the problem of poor long-term stability of conventional Beta zeolite molecular sieve-based catalytic diesel hydrocracking catalysts in the prior art, the present invention provides a catalytic diesel hydrocracking catalyst and a preparation method and application thereof. The present invention uses a Beta zeolite molecular sieve with an excess of chiral polymorph A as a catalytic diesel hydrocracking catalyst with an acid functional cracking active component, which can effectively improve the long-term stability of conventional Beta zeolite molecular sieve-based catalysts, so that the catalyst maintains high catalytic activity and single-pass conversion rate during a long operating time.

[0007] One of the objects of the present invention is to provide a catalytic diesel hydrocracking catalyst comprising the following components:

[0008] a) Beta zeolite molecular sieve;

[0009] b) metal active components;

[0010] c) binder;

[0011] The content of chiral polymorph A in the Beta zeolite molecular sieve is 46-70wt%, preferably 50-70wt%, more preferably 50-65wt%, and most preferably 55-65wt%.

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

[0013] The molecular ratio of silicon to aluminum oxide of the Beta zeolite molecular sieve is 20-200, preferably 50-120.

[0014] The Beta zeolite molecular sieve used in the catalytic diesel hydrocracking catalyst of the present invention is a Beta zeolite molecular sieve with excess chiral polymorph A within a certain silicon-aluminum ratio range. The preparation method of the Beta zeolite molecular sieve with excess chiral polymorph A can refer to the full text of Chinese patent CN106892435A, and the full text of CN106892435A is introduced here.

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

[0016] The metal active component includes at least one of Group VIII metals, Group VIII metal sulfides, Group VIB metal oxides, and Group VIB metal sulfides, and preferably includes 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.

[0017] In a preferred embodiment of the present invention,

[0018] The Group VIII metal includes at least one of platinum, palladium, ruthenium, cobalt, nickel and iridium; and / or,

[0019] The VIB group metal oxide includes at least one of molybdenum oxide and tungsten oxide, preferably includes at least one of molybdenum dioxide, molybdenum trioxide, tungsten dioxide and tungsten trioxide; and / or,

[0020] The Group VIII metal sulfide comprises at least one of sulfides of iron, cobalt and nickel; and / or,

[0021] The VIB group metal sulfide includes at least one of molybdenum disulfide and tungsten disulfide.

[0022] In a preferred embodiment of the present invention,

[0023] The binder includes at least one of aluminum oxide, silicon oxide, silicon oxide-aluminum oxide composite, and amorphous silicon aluminum.

[0024] In a preferred embodiment of the present invention,

[0025] In terms of mass percentage,

[0026] The Beta zeolite molecular sieve accounts for 5-80wt% of the catalyst mass, preferably 20-75wt%, more preferably 30-70wt%; and / or,

[0027] The metal active component accounts for 3-35wt% of the catalyst mass, preferably 5-23wt%; and / or,

[0028] The binder accounts for 0-80 wt % of the catalyst mass, preferably 15-50 wt %.

[0029] In a preferred embodiment of the present invention,

[0030] In terms of mass percentage,

[0031] 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,

[0032] The VIB Group metal oxide and / or sulfide accounts for 3-25 wt %, preferably 5-15 wt % of the catalyst mass.

[0033] The second object of the present invention is to provide a method for preparing the catalytic diesel hydrocracking catalyst of the first object of the present invention, comprising loading the metal active component on a carrier including the Beta zeolite molecular sieve, and then reducing and / or sulfurizing to obtain the catalytic diesel hydrocracking catalyst.

[0034] 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 and a binder, loading the metal active component compound, and then drying and calcining to obtain a catalyst precursor, and reducing 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 metal and catalyst carrier in the art. Preferably, the following specific steps can be included:

[0035] 1) kneading and extruding the components including the Beta zeolite molecular sieve and the binder, drying and then calcining in an air atmosphere at 500-600° C. to obtain a catalyst carrier;

[0036] 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;

[0037] 3) reducing the obtained catalyst precursor under hydrogen conditions at 400-500° C. to obtain the catalyst;

[0038] Alternatively, the obtained catalyst precursor is sulfurized under a sulfurization condition of 280-360° C. to obtain the catalyst;

[0039] Alternatively, the obtained catalyst precursor is reduced with hydrogen and then sulfided to obtain the catalyst.

[0040] The third object of the present invention is to provide a catalytic diesel hydrocracking catalyst according to the first object of the present invention or a catalytic diesel hydrocracking catalyst obtained by the preparation method according to the second object of the present invention in a hydrocatalytic diesel hydrocracking reaction, comprising the step of contacting the catalyst with hydrocatalytic diesel under hydrocracking conditions.

[0041] In a preferred embodiment of the present invention,

[0042] The feedstock oil suitable for the catalyst of the present invention in the hydrocracking reaction is hydrogenated catalytic diesel that has been subjected to hydrofining treatment, the catalytic diesel T95 ≤ 360°C, preferably ≤ 345°C, and the total nitrogen content of the hydrogenated catalytic diesel obtained after hydrofining is ≤ 15ppm, preferably ≤ 10ppm.

[0043] In a preferred embodiment of the present invention,

[0044] The process conditions of the hydrocracking reaction include:

[0045] Reactor inlet temperature 280-450°C, preferably 310-430°C, more preferably 350-410°C; and / or,

[0046] Hydrogen partial pressure 5-10 MPa, preferably 5-9 MPa, more preferably 6-8 MPa; and / or,

[0047] Mass airspeed 0.5-2.0h -1 , preferably 0.6-1.5h -1 , more preferably 0.8-1.2h -1 and / or,

[0048] The volume ratio of fresh hydrogen to hydrogenated catalytic diesel is 400-1000, preferably 500-800, more preferably 500-600; and / or,

[0049] 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.

[0050] In a preferred embodiment of the present invention,

[0051] When the hydrocracking catalyst of the present invention is used to carry out the reaction under the above hydrocracking reaction conditions, and the operation time is greater than or equal to 700 hours, the hydrocracking reaction product satisfies C 11+ The single-pass conversion of the components is greater than 85%, preferably greater than 90%.

[0052] Beneficial effects of the present invention: The present invention provides a catalytic diesel hydrocracking catalyst, which can be applied to the hydrocracking reaction of hydrocatalytic diesel, and realizes 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. The present invention uses Beta zeolite molecular sieves with excessive chiral polymorph A within a certain silicon-aluminum ratio as the catalyst acid functional cracking active component, which can effectively improve the long-term stability of conventional Beta zeolite molecular sieve-based catalytic diesel hydrocracking catalysts, so that the catalyst maintains high catalytic activity and single-pass conversion rate during a long operating time. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a comparison diagram of the XRD spectrum of the Beta-1 sample in Example 1 of the present invention and the standard XRD spectrum of the Beta zeolite molecular sieve with a chiral polymorph A content of 65% simulated by the DIFFaX program; in the figure, the abscissa is the diffraction angle 2θ (°), and the ordinate is the intensity;

[0054] Figure 2 This is a comparison diagram of the XRD spectrum of the Beta-2 sample in Comparative Example 1 of the present invention and the standard XRD of the Beta zeolite molecular sieve with a chiral polymorph A content of 44% simulated by the DIFFaX program; in the figure, the abscissa is the diffraction angle 2θ (°), and the ordinate is the intensity;

[0055] Figure 3 This is a comparison diagram of the XRD spectrum of the Beta-3 sample in Comparative Example 2 of the present invention and the standard XRD of the Beta zeolite molecular sieve with a chiral polymorph A content of 65% simulated by the DIFFaX program; in the figure, the abscissa is the diffraction angle 2θ (°), and the ordinate is the intensity;

[0056] Figure 4 This is a comparison diagram of the XRD spectrum of the Beta-4 sample in Example 2 of the present invention and the standard XRD spectrum of the Beta zeolite molecular sieve with a chiral polymorph A content of 55% simulated by the DIFFaX program; in the figure, the abscissa is the diffraction angle 2θ (°), and the ordinate is the intensity;

[0057] Figure 5 For each catalyst C in the examples and comparative examples 11+ The trend of component single-pass conversion rate changing with running time; in the figure, the horizontal axis is running time (h) and the vertical axis is conversion rate (%). DETAILED DESCRIPTION

[0058] The present invention is described in detail below in conjunction with specific embodiments and drawings. 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 content of the present invention still fall within the scope of protection of the present invention.

[0059] 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 crystal phase of Beta zeolite molecular sieve in the catalyst is analyzed by X-ray diffraction spectroscopy (XRD); the metal valence and composition in the catalyst are determined by X-ray photoelectron spectroscopy (XPS). XRF, ICP, XRD and XPS characterization are respectively carried out by Rigaku ZSX100e X-ray fluorescence spectrometer, Varian 700-ES series inductively coupled plasma emission spectrometer, Bruker D8 Advance SS X-ray diffractometer and PerkinElmer PHI5000CESCA X-ray photoelectron spectrometer.

[0060] In the present invention, the hydrocarbon composition of the hydrocracking product is determined by online gas chromatography. The chromatographic model is Agilent7890A, equipped with an 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. The total nitrogen content in the oil product is analyzed by Elab6600SN sulfur and nitrogen element analyzer.

[0061] The calculation basis of the main result data involved in the specific implementation method of the present invention is:

[0062]

[0063]

[0064] In the above formula, C 11+ The content of the components in the liquid phase was measured by chromatography, and the liquid phase yield was calculated by dividing the weighed mass of the product per hour by the feed amount per hour.

[0065] The raw materials used in the examples are all conventional commercially available raw materials.

[0066] Example 1

[0067] Preparation of chiral polymorph A excess Beta zeolite molecular sieve Beta-1:

[0068] The preparation method refers to Example 1 of the patent CN106892435A specification, and the specific preparation process is as follows:

[0069] 90.2g of tetraethyl orthosilicate, 44.4g of 35% tetraethylammonium hydroxide aqueous solution, and 90g of deionized water were mixed in a beaker, and the beaker was sealed with a sealing film and stirred for 5 hours to completely hydrolyze the tetraethyl orthosilicate, and 0.80g of sodium aluminate was added and stirred for 1 hour. The sealing film was removed, and the resulting mixture was stirred for 6 hours in a fume hood to evaporate the ethanol and water in the system to form a jelly, and then freeze-dried until the molar ratio of H2O to SiO2 in the system was less than 1, and the mass of the dry glue was 43.2g. 43.2g of dry glue was mixed with 3.8g of solid ammonium fluoride and 4.8g of solid L-histidine and ground into a uniform powder (100 mesh), and the resulting powder was transferred to a stainless steel reactor lined with polytetrafluoroethylene and placed in a 150°C oven for crystallization for 7 days. After the crystallization is completed and the product is cooled to room temperature, it is washed with deionized water until neutral, filtered, dried in an oven at 60°C, and calcined in a muffle furnace at 550°C for 6 hours to remove the template to obtain Beta-1 zeolite molecular sieve with excess chiral polymorph A. The product mass is 27g.

[0070] Beta-1 zeolite molecular sieve was characterized and analyzed by XRD and XRF. The XRD spectrum is shown in Figure 1 The XRD analysis showed that the relative content of chiral polymorph A in the Beta-1 zeolite molecular sieve sample was about 65%, and the XRF result showed that the molecular molar ratio of silicon-aluminum oxide in the Beta-1 zeolite molecular sieve was 80.

[0071] Preparation of catalytic diesel hydrocracking catalyst:

[0072] 20.0g of Beta-1 zeolite molecular sieve and 20.7g of pseudo-boehmite were kneaded and extruded, then dried at 90°C and calcined at 550°C in air atmosphere for 4 hours to obtain a catalyst carrier. 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 / 50.0wt%Beta-1 molecular sieve-40.3wt%Al2O3.

[0073] Application of catalyst:

[0074] The hydrocracking reactor was loaded with 10.0 g of catalyst. The properties of the hydrocatalytic diesel feedstock used and the hydrocracking reaction conditions are shown in Table 1. The initial conversion rate of the catalyst, i.e., C 11+ The single-pass conversion rate of the components was 98%. After 700 hours of stable operation, C 11+The component single-pass conversion rate can still reach more than 91% (see Figure 5 ).

[0075] Table 1 Raw material properties and hydrocracking reaction conditions

[0076] Example 1 Example 3 Comparative Example 3 Catalytic diesel T95(℃) 340 356 356 Hydrogen content of catalytic diesel fuel (ppm) 8.8 10.0 18.8 Hydrogen partial pressure (Mpa) 7.0 7.0 7.0 Inlet temperature(℃) 360 370 370 Fresh Hydrogen Hydrogen Oil Volume Ratio 540 830 830 Mixed hydrogen oil volume ratio 2000 2000 2000 <![CDATA[Mass space velocity (h -1 )]]> 1.0 1.0 1.0

[0077] Comparative Example 1

[0078] Preparation of conventional Beta zeolite molecular sieve Beta-2:

[0079] The specific preparation process is substantially the same as that of Example 1, except that solid L-histidine is not added, and 43.2 g of dry gel is mixed with only 3.8 g of solid ammonium fluoride and ground into a uniform powder (100 mesh).

[0080] Beta-2 zeolite molecular sieve was characterized and analyzed by XRD and XRF. The XRD spectrum is shown in Figure 2 The XRD analysis showed that the Beta-2 zeolite molecular sieve sample was a conventional Beta zeolite molecular sieve, and the relative content of chiral polymorph A was about 44%. The XRF results showed that the molar ratio of silicon-aluminum oxide molecules in the Beta-1 zeolite molecular sieve was 80.

[0081] Preparation of catalytic diesel hydrocracking catalyst:

[0082] The specific preparation process is basically the same as that in Example 1, except that the Beta-1 zeolite molecular sieve in Example 1 is replaced by Beta-2 zeolite molecular sieve, and the final catalyst composition is: 3.5wt% Ni-5.2wt% MoO2-1.0wt% MoO3 / 50.0wt% Beta-2 molecular sieve-40.3wt% Al2O3.

[0083] Application of catalyst:

[0084] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock and the hydrocracking reaction conditions used were the same as those in Example 1. The initial conversion rate of the catalyst, i.e., C 11+ The single-pass conversion rate of the components was 98%. After the catalyst was operated stably for 700 hours, C 11+ The single-pass conversion rate of the components dropped to 80% (see Figure 5 ).

[0085] Comparative Example 2

[0086] Preparation of chiral polymorph A excess Beta zeolite molecular sieve Beta-3:

[0087] The specific preparation process is basically the same as that of Example 1, except that the amount of sodium aluminate added is reduced from 0.80 g to 0.20 g.

[0088] Beta-3 zeolite molecular sieve was characterized and analyzed by XRD and XRF. The XRD spectrum is shown in Figure 3 The XRD analysis showed that the relative content of chiral polymorph A in the Beta-1 zeolite molecular sieve sample was about 65%, and the XRF result showed that the molecular molar ratio of silicon to aluminum oxide in the Beta-1 zeolite molecular sieve was 300.

[0089] Preparation of catalytic diesel hydrocracking catalyst:

[0090] The specific preparation process is basically the same as that in Example 1, except that the Beta-1 zeolite molecular sieve in Example 1 is replaced by Beta-3 zeolite molecular sieve, and the final catalyst composition is also: 3.5wt% Ni-5.2wt% MoO2-1.0wt% MoO3 / 50.0wt% Beta-3 molecular sieve-40.3wt% Al2O3.

[0091] Application of catalyst:

[0092] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock and the hydrocracking reaction conditions used were the same as those in Example 1. The initial conversion rate of the catalyst, i.e., C 11+ The single-pass conversion rate of the components was only 87%. After 700 hours of stable operation, C 11+ The component conversion rate per pass is about 74% (see Figure 5 ),.

[0093] Example 2

[0094] Preparation of chiral polymorph A excess Beta zeolite molecular sieve Beta-4:

[0095] The preparation method refers to Example 3 of the patent CN106892435A specification, and the specific preparation process is as follows:

[0096] 90.2g of tetraethyl orthosilicate, 44.4g of 35% tetraethylammonium hydroxide aqueous solution, and 100g of deionized water were mixed in a beaker, and the beaker was sealed with a sealing film and stirred for 4 hours to completely hydrolyze the tetraethyl orthosilicate, and 0.93g of sodium aluminate was added and stirred for 1 hour. The sealing film was removed, and the resulting mixture was stirred for 6 hours in a fume hood to evaporate the ethanol and water in the system to form a jelly, and then freeze-dried until the molar ratio of H2O to SiO2 in the system was less than 1, and the mass of the dry glue was 43.3g. 43.3g of dry glue was mixed with 7.8g of solid ammonium fluoride and 7.4g of solid L-lysine and ground into a uniform powder (100 mesh), and the resulting powder was transferred to a stainless steel reactor lined with polytetrafluoroethylene and placed in a 150°C oven for crystallization for 7 days. After the crystallization is completed and the product is cooled to room temperature, it is washed with deionized water until neutral, filtered, dried in an oven at 60°C, and calcined in a muffle furnace at 550°C for 6 hours to remove the template to obtain Beta-4 zeolite molecular sieve with excess chiral polymorph A. The product mass is 27.2g.

[0097] Beta-4 zeolite molecular sieve was characterized and analyzed by XRD and XRF. The XRD spectrum is shown in Figure 4 The XRD analysis showed that the relative content of chiral polymorph A in the Beta-4 zeolite molecular sieve sample was about 55%, and the XRF result showed that the molecular molar ratio of silicon-aluminum oxide in the Beta-4 zeolite molecular sieve was 58.

[0098] Preparation of catalytic diesel hydrocracking catalyst:

[0099] 20.0g of Beta-4 zeolite molecular sieve and 21.1g of pseudo-boehmite were kneaded and extruded, and then dried at 90℃ and calcined at 550℃ in air atmosphere for 4 hours to obtain a catalyst carrier. Then 6.24g of nickel nitrate hexahydrate and 2.17g of ammonium metatungstate 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 450℃ for 4h in a hydrogen flow rate of 80ml / min, then cooled to 320℃ 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 / 50wt%Beta-4 molecular sieve-41.0wt%Al2O3.

[0100] Application of catalyst:

[0101] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock and the hydrocracking reaction conditions used were the same as those in Example 1. The initial conversion rate of the catalyst, i.e., C 11+ The single-pass conversion rate of the components was 98%. After the catalyst was operated stably for 700 hours, C 11+The component single-pass conversion rate can still reach more than 86% (see Figure 5 ).

[0102] Example 3

[0103] Preparation of catalytic diesel hydrocracking catalyst:

[0104] 20.0g of Beta-1 zeolite molecular sieve and 20.7g of pseudo-boehmite were kneaded and extruded, dried at 90℃ and calcined at 550℃ in air atmosphere for 4 hours to obtain a catalyst carrier. 6.24g of cobalt 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℃ and calcined at 520℃ for 2h to obtain a catalyst precursor. The catalyst precursor was reduced at 400℃ in a hydrogen atmosphere of 80ml / min for 4h to obtain a catalyst composition of: 3.5wt%Co-5.2wt%MoO2-1.0wt%MoO3 / 50.0wt%Beta-4 molecular sieve-40.3wt%Al2O3.

[0105] Application of catalyst:

[0106] The hydrocracking reactor was loaded with 10.0 g of catalyst. The properties of the hydrocatalytic diesel feedstock used and the hydrocracking reaction conditions are shown in Table 1. The initial conversion rate of the catalyst, i.e., C 11+ The single-pass conversion rate of the components was 97%. After the catalyst was operated stably for 700 hours, C 11+ The component single-pass conversion rate can still reach more than 86% (see Figure 5 ).

[0107] Comparative Example 3

[0108] Application of catalyst:

[0109] The hydrocracking reactor was loaded with 10.0 g of the catalytic diesel hydrocracking catalyst in Example 3. The properties of the hydrocatalytic diesel feedstock and the hydrocracking reaction conditions used are shown in Table 1. The total nitrogen content of the hydrocatalytic diesel was 18.8 ppm. The initial conversion rate of the catalyst, i.e., C 11+ The single-pass conversion rate of the components was 96%. After the catalyst was operated stably for 700 hours, C 11+ The component conversion rate per pass is about 80% (see Figure 5 ).

[0110] Example 4

[0111] Preparation of catalytic diesel hydrocracking catalyst:

[0112] 27.0g of Beta-1 zeolite molecular sieve and 11.7g of pseudo-boehmite were kneaded and extruded, then dried at 90°C and calcined at 550°C in air atmosphere for 4 hours to obtain a catalyst carrier. 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 / 67.5wt%Beta-1 molecular sieve-22.8wt%Al2O3.

[0113] Application of catalyst:

[0114] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock and the hydrocracking reaction conditions used were the same as those in Example 3. The initial conversion rate of the catalyst, i.e., C 11+ The single-pass conversion rate of the components was 98%. After the catalyst was operated stably for 700 hours, C 11+ The single-pass conversion rate of the components can still reach over 87%.

[0115] Example 5

[0116] Preparation of chiral polymorph A excess Beta zeolite molecular sieve Beta-5:

[0117] The preparation method refers to Example 3 of the patent CN106892435A specification, and the specific preparation process is as follows:

[0118] 90.2g of tetraethyl orthosilicate, 44.4g of 35% tetraethylammonium hydroxide aqueous solution, and 100g of deionized water were mixed in a beaker, and the beaker was sealed with a sealing film and stirred for 4 hours to completely hydrolyze the tetraethyl orthosilicate, and 0.62g of sodium aluminate was added and stirred for 1 hour. The sealing film was removed, and the resulting mixture was stirred for 6 hours in a fume hood to evaporate the ethanol and water in the system to form a jelly, and then freeze-dried until the molar ratio of H2O to SiO2 in the system was less than 1, and the mass of the dry glue was 43.0g. 43.0g of the dry glue was mixed with 7.8g of solid ammonium fluoride and 7.4g of solid L-lysine and ground into a uniform powder (100 mesh), and the resulting powder was transferred to a stainless steel reactor lined with polytetrafluoroethylene and placed in a 150°C oven for crystallization for 7 days. After the crystallization is completed and the product is cooled to room temperature, it is washed with deionized water until neutral, filtered, dried in an oven at 60°C, and calcined in a muffle furnace at 550°C for 6 hours to remove the template to obtain Beta-5 zeolite molecular sieve with excess chiral polymorph A. The product mass is 26.8g.

[0119] The XRD analysis showed that the relative content of chiral polymorph A in the Beta-5 zeolite molecular sieve sample was about 55%, and the XRF result showed that the molecular molar ratio of silicon-aluminum oxide in the Beta-5 zeolite molecular sieve was 110.

[0120] Preparation of catalytic diesel hydrocracking catalyst:

[0121] 20.0g of Beta-5 zeolite molecular sieve and 21.1g of pseudo-boehmite were kneaded and extruded, and then dried at 90℃ and calcined at 550℃ in air atmosphere for 4 hours to obtain a catalyst carrier. Then 6.24g of nickel nitrate hexahydrate and 2.17g of ammonium metatungstate 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 450℃ for 4h in a hydrogen flow rate of 80ml / min, then cooled to 320℃ 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 / 50wt%Beta-5 molecular sieve-41.0wt%Al2O3.

[0122] Application of catalyst:

[0123] The hydrocracking reactor was loaded with 10.0 g of catalyst, and the properties of the hydrocatalytic diesel feedstock and the hydrocracking reaction conditions used were the same as those in Example 1. The initial conversion rate of the catalyst, i.e., C 11+ The single-pass conversion rate of the components was 97%. After the catalyst was operated stably for 700 hours, C 11+ The single-pass conversion rate of components can still reach more than 85%.

[0124] It can be seen from Example 1 and Comparative Example 1 that when the relative content of chiral polymorph A is lower than the range of the present invention, the catalyst cannot stably maintain a high single-pass conversion rate; it can be seen from Example 1 and Comparative Example 2 that when the silicon-aluminum ratio range is not within the range of the present invention, the catalyst still cannot stably maintain a high single-pass conversion rate; it can be seen from Example 3 and Comparative Example 3 that the catalytic diesel hydrocracking catalyst of the present invention is preferably suitable for hydrogenated catalytic diesel with a total nitrogen content of ≤15ppm.

[0125] It can be seen from Examples 1-5 that the present invention can effectively improve the long-term stability of conventional Beta zeolite molecular sieve-based catalytic diesel hydrocracking catalysts by using Beta zeolite molecular sieves with excess chiral polymorph A within a certain silicon-aluminum ratio as the catalyst acid functional cracking active component, so that the catalyst can maintain a high single-pass conversion rate during a long operating time. When the operating time is greater than or equal to 700 hours, the hydrocracking reaction product meets C 11+ The single-pass conversion of the components is greater than 85%, preferably greater than 90%.

Claims

1. A catalytic diesel hydrocracking catalyst comprising the following components: a) Beta zeolite molecular sieve; b) metal active components; c) binder; The content of chiral polymorph A in the Beta zeolite molecular sieve is 46-70wt%, preferably 50-70wt%, and more preferably 50-65wt%.

2. The catalytic diesel hydrocracking catalyst according to claim 1, characterized in that: The molecular ratio of silicon to aluminum oxide of the Beta zeolite molecular sieve is 20-200, preferably 50-120.

3. The catalytic diesel hydrocracking catalyst according to claim 1, characterized in that: The metal active component includes at least one of Group VIII metals, Group VIII metal sulfides, Group VIB metal oxides, and Group VIB metal sulfides, and preferably includes 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.

4. The catalytic diesel hydrocracking catalyst as claimed in claim 3, 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 oxide and tungsten oxide, preferably includes 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.

5. The catalytic diesel hydrocracking catalyst according to claim 1, characterized in that: The binder includes at least one of aluminum oxide, silicon oxide, silicon oxide-aluminum oxide composite, and amorphous silicon aluminum.

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

7. The catalytic diesel hydrocracking catalyst as claimed in claim 3, 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.

8. A method for preparing the catalytic diesel hydrocracking catalyst according to any one of claims 1 to 7, comprising loading the metal active component on a carrier comprising the Beta zeolite molecular sieve, and then reducing and / or sulfurizing to obtain the catalytic diesel hydrocracking catalyst.

9. Use of the catalytic diesel hydrocracking catalyst according to any one of claims 1 to 7 or the catalytic diesel hydrocracking catalyst obtained by the preparation method according to claim 8 in a hydrocracking reaction of hydrogenated catalytic diesel, comprising the step of contacting the catalyst with hydrogenated catalytic diesel under hydrocracking conditions.

10. The use according to claim 9, characterized in that: The catalytic diesel has a T95 of ≤360°C, preferably ≤345°C, and the total nitrogen content of the hydrogenated catalytic diesel obtained after hydrogenation refining is ≤15ppm, preferably ≤10ppm.

11. The use according to claim 9, 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.

12. The use according to claim 9, characterized in that: When the catalyst operation time is greater than or equal to 700 hours, the hydrocracking reaction product satisfies C 11+ The single-pass conversion of the components is greater than 85%, preferably greater than 90%.

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