Modified y molecular sieve, preparation method and application thereof

Abstract

The application discloses a modified Y molecular sieve, a preparation method and application thereof. The modified Y molecular sieve is a RE- USY molecular sieve, the molecular sieve contains rare earth elements, and the rare earth elements are one or more of lanthanum or cerium; the RE- USY molecular sieve has the following properties: a mesopore pore volume accounts for 30% to 60% of a total pore volume of the molecular sieve. The modified Y molecular sieve is particularly suitable for being used as an acid component of a hydrocracking molecular sieve, and when a hydrocracking catalyst is prepared from the modified molecular sieve, the reaction activity and selectivity can be improved.

Description

Technical Field

[0001] This invention belongs to the field of Y molecular sieve preparation technology, specifically relating to a modified Y molecular sieve, its preparation method, and its application. Background Technology

[0002] Hydrocracking catalysts are bifunctional catalysts, and Y-type molecular sieves are widely used as the main cracking component in hydrocracking catalysts. The active component of the molecular sieve has a significant impact on the overall reaction performance of the catalyst, and the production cost of the molecular sieve component is one of the main costs in catalyst preparation. Y-type molecular sieves have a pore size of only 0.74 nm and are used to process heavy fractions such as heavy oil and residue oil. The accessibility of the active center becomes a major obstacle to the cracking of polycyclic aromatic hydrocarbons, polycyclic cycloalkanes, and other polycyclic compounds. At the same time, because heavy oil and residue oil contain large molecular compounds such as gums and asphaltenes that easily produce coke, as well as heavy metals such as nickel and vanadium, the structure of the molecular sieve in the catalyst is severely damaged under high-temperature hydrothermal conditions, resulting in reduced activity and poor product distribution.

[0003] Currently, rare earth elements are commonly used to modify molecular sieves or catalysts to improve the activity and stability of catalytic cracking catalysts. How to promote the migration of rare earth ions and increase the occupancy of rare earth ions at the locked cation sites directly affects the performance of rare earth Y molecular sieves and the activity and stability of catalysts using them as active components. To promote the migration of rare earth ions into the sodalite cages, high-temperature calcination or high-temperature hydrothermal calcination methods are commonly used in industry. However, excessively high calcination temperatures not only place more stringent requirements on the materials of industrial calcination furnaces, but also cause rare earth ions already locked in positions to tend to return to the cages. CN1026225C discloses a method for preparing rare earth Y molecular sieves, which involves reacting NaY molecular sieves with RE... 3+ After undergoing one ion exchange in an aqueous solution, it is calcined at 450–600°C in 100% flowing steam for 1–3 hours.

[0004] Currently, conventional post-processing modification methods have limited impact on the properties of Y-zeolites, as heteroatoms are difficult to integrate into the Y-zeolite framework. Microporous zeolites have limited pore sizes, and their reaction performance is constrained by the pore structure. Therefore, it is necessary to synthesize a stable Y-zeolite with a hierarchical pore structure to overcome the diffusion limitations of macromolecular reactants. Consequently, constructing heteroatom-modified Y-zeolites during their synthesis and controlling their related properties simplifies subsequent modification steps, ultimately leading to the preparation of higher-performance hydrocracking catalysts – a problem that urgently needs to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a modified Y molecular sieve, its preparation method, and its applications. This modified molecular sieve is particularly suitable as an acidic component of hydrocracking molecular sieves, and its use in preparing hydrocracking catalysts can improve reaction activity and selectivity.

[0006] The first aspect of the present invention provides a RE-USY molecular sieve, wherein the molecular sieve contains rare earth elements, wherein the rare earth elements are one or more of lanthanum or cerium; the properties of the RE-USY molecular sieve are as follows: the mesoporous pore volume accounts for 30% to 60% of the total pore volume of the molecular sieve, preferably 40% to 53%.

[0007] Furthermore, the properties of the RE-USY molecular sieve are as follows: the ratio of Brønsted acid to Lønsted acid is 1.25 to 1.50 at 200℃, and the ratio of Brønsted acid to Lønsted acid is 1.10 to 1.30 at 350℃.

[0008] Furthermore, the properties of the RE-USY molecular sieve are as follows: specific surface area of ​​550–730 m². 2 / g, with a pore volume of 0.35~0.65mL / g.

[0009] Furthermore, in the RE-USY molecular sieve, the average size of the crystal grains is 0.3–1.2 μm, preferably 400–600 nm.

[0010] Furthermore, the unit cell constant of the RE-USY molecular sieve is

[0011] Furthermore, in the RE-USY molecular sieve, the SiO2 / Al2O3 molar ratio is 8.0 to 35.0, preferably 15.0 to 20.0.

[0012] Furthermore, in the RE-USY molecular sieve, the total acid content is 420-500 μmol / g at 200℃ and 130-150 μmol / g at 350℃.

[0013] Furthermore, in the RE-USY molecular sieve, based on the mass of the RE-USY molecular sieve, the content of rare earth elements, calculated as oxides, is 0.10% to 1.50%.

[0014] A second aspect of this invention provides a method for preparing RE-USY molecular sieves, comprising the following steps:

[0015] (1) Preparation of B-containing Y molecular sieve guide bodies;

[0016] (2) The matrix mixture is mixed with the guide body from step (1) to obtain a gel;

[0017] (3) Crystallize the gel from step (2);

[0018] (4) The crystallized product obtained in step (3) is subjected to first ammonium exchange and first hydrothermal treatment to obtain heteroatom modified Y molecular sieve precursor;

[0019] (5) The precursor obtained in step (4) is subjected to a second ammonium exchange and a second hydrothermal treatment to obtain the modified Y molecular sieve, namely RE-USY molecular sieve;

[0020] In step (4), the first ammonium exchange is carried out using a mixed solution of ammonium salt and rare earth compound for ion exchange.

[0021] Further, in step (1), the preparation method of the B-containing Y molecular sieve guide includes: mixing a first aluminum source, a first alkali source, a first B source, a first silicon source, and water, and allowing it to stand to obtain the B-containing Y molecular sieve guide. The first B source is selected from at least one of sodium metaborate, boric acid, ammonium fluoroborate, and borax. The first aluminum source is selected from at least one of sodium aluminate and aluminum sulfate; the first alkali source is selected from at least one of NaOH and KOH; and the first silicon source is selected from at least one of silica sol and water glass.

[0022] Further, in step (1), in the method for preparing the Y molecular sieve guide containing B, the first aluminum source is calculated as Al2O3, the first alkali source is calculated as NaOH, the first B source is calculated as B2O3, the first silicon source is calculated as SiO2, and the molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O is 1:(11~42):(0.07~20.0):(5~25):(180~450), preferably 1:(15~35):(0.07~12.0):(5~18):(180~400).

[0023] Furthermore, in step (1), in the preparation method of the Y molecular sieve guide containing B, the standing temperature is 10-50℃ and the standing time is 15-35 hours.

[0024] Further, in step (1), in the method for preparing the B-containing Y molecular sieve guide, preferably, the first aluminum source and the first alkali source are mixed and dissolved in water, and then the first B source and the first silicon source are added in sequence, mixed evenly, and allowed to stand to obtain the B-containing Y molecular sieve guide.

[0025] Further, in step (2), the matrix mixture is a second aluminum source, a second silicon source, a second B source, a second alkali source, and water.

[0026] Further, in step (2), the second B source is selected from at least one of sodium metaborate, boric acid, ammonium fluoroborate, and borax. The second aluminum source is selected from at least one of sodium aluminate and aluminum sulfate. The second alkali source is selected from at least one of NaOH and KOH. The second silicon source is selected from at least one of silica sol and water glass.

[0027] Further, in step (2), in the matrix mixture, the second aluminum source is calculated as Al2O3, the second alkali source is calculated as NaOH, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O is 1:(1.5~15.0):(0.07~15.0):(1.5~12.0):(80~400), preferably 1:(1.5~10.0):(0.07~8.0):(1.5~8.0):(80~350).

[0028] Furthermore, in step (2), the amount of Y molecular sieve guide containing B added is 10.0% to 45.0% of the total mass of the matrix mixture.

[0029] Further, in step (2), the second B source is introduced into the reaction system as a second B source feed, and the second B source feed is preferably prepared by at least one of the following methods:

[0030] a. At least a portion of the second B source and at least a portion of the second silicon source are used to form a second B source feed.

[0031] b. At least a portion of the second B source and at least a portion of the second aluminum source are used to form the second B source feed.

[0032] c. At least a portion of the second B source is fed with at least a portion of the second aluminum source and at least a portion of the second silicon source to form the second B source feed.

[0033] Further, in step (2), the mass content of B (calculated as oxide) in the second B source feed is 2.0% to 18.0%, preferably 10.0% to 18.0%. Preferably, in step (2), the second B source feed is ultrasonically treated and then subjected to a settling process (preferably, the settling time is 1 to 48 hours, more preferably 12 to 24 hours) before being introduced into the reaction system. Preferably, the ultrasonic treatment conditions are as follows: temperature 20 to 80°C, more preferably 20 to 60°C, ultrasonic frequency 20 to 45 kHz, time 1 to 8 hours, more preferably 1 to 4 hours.

[0034] Further, in step (2), the matrix mixture (second aluminum source, second silicon source, second B source, second alkali source and water) is mixed with the guide body from step (1) to obtain a gel. Specifically, the second alkali source and the second silicon source are mixed evenly with water, and then the guide body, the second B source and the second aluminum source obtained in step (1) are added in sequence and mixed evenly to obtain a gel.

[0035] Further, in step (2), the matrix mixture (second aluminum source, second silicon source, second B source, second alkali source and water) is mixed with the guide body from step (1) to obtain a gel. Preferably, the second B source is introduced into the reaction system as a second B source feed. Specifically, the second alkali source and the remaining second silicon source are mixed evenly with water, and then the guide body obtained in step (1), the second B source feed, and the remaining second aluminum source are added in sequence and mixed evenly to obtain a gel. The remaining second silicon source or the remaining second aluminum source refers to the second silicon source or the second aluminum source remaining after the second silicon source or the second aluminum source used in the preparation of the second B source feed.

[0036] Furthermore, in step (3), the crystallization adopts a three-stage temperature-increasing crystallization method. The first-stage crystallization temperature is 30-40°C, the second-stage crystallization temperature is 30-35°C higher than the first-stage temperature, and the third-stage crystallization temperature is 25-50°C higher than the second-stage temperature, with the highest temperature not exceeding 110°C. The crystallization time for each stage is 12-36 hours, preferably 15-24 hours.

[0037] Further, in step (4), the first ammonium exchange uses a mixed salt solution of ammonium salt and rare earth compound for ion exchange. The ammonium salt used can be one or more of ammonium chloride, ammonium nitrate, and ammonium sulfate, wherein the concentration of the ammonium salt solution is 0.1–3.0 mol / L; the rare earth compound used is at least one of rare earth chloride and rare earth nitrate, which can be a single rare earth or a mixed rare earth, such as lanthanum chloride, lanthanum nitrate, cerium chloride, cerium nitrate, etc., and one or more of rare earth chloride or rare earth nitrate, wherein the amount of rare earth compound added is 1.0%–20.0% of the mass of the crystallized product obtained in step (3). The pH value of the ammonium exchange is 1.0–7.0, preferably 2.0–7.0, the ammonium exchange temperature is 30–90℃, preferably 40–60℃, and the number of ammonium exchanges is 1–5. The solid-liquid volume ratio of each ammonium exchange is 1:10–1:20, and the treatment time of each ammonium exchange is 3–6 hours.

[0038] Further, in step (4), the first hydrothermal treatment is performed 1 to 3 times, preferably 2 times, and the hydrothermal treatment conditions for each time are as follows: temperature of 500 to 650°C, 100% steam treatment, and treatment time of 1 to 6 hours. The steam treatment can be closed steam treatment or flowing steam treatment, preferably flowing steam treatment.

[0039] Further, in step (5), the second ammonium exchange is a conventional ammonium exchange. The ammonium salt used can be one or more of ammonium chloride, ammonium nitrate, and ammonium sulfate, wherein the concentration of the ammonium salt solution is 0.1–3.0 mol / L, the pH value is 1.0–7.0, preferably 2.0–7.0. The ammonium exchange temperature is 30–90℃, preferably 40–60℃, and the number of ammonium exchanges is 1–5. The solid-liquid volume ratio of each ammonium exchange is 1:10–1:20, and the treatment time for each ammonium exchange is 3–6 hours.

[0040] Further, in step (5), the second hydrothermal treatment is performed 1 to 3 times, preferably 2 times, with the following conditions for each hydrothermal treatment: temperature of 500 to 650°C, 100% steam treatment, and treatment time of 1 to 6 hours. The steam treatment can be closed steam treatment or flowing steam treatment, preferably flowing steam treatment.

[0041] Furthermore, the RE-USY molecular sieve has the following properties: the mesoporous pore volume accounts for 30% to 60% of the total pore volume of the molecular sieve, preferably 40% to 53%.

[0042] Furthermore, the properties of the RE-USY molecular sieve are as follows: specific surface area of ​​550–730 m². 2 / g, with a pore volume of 0.35~0.65mL / g.

[0043] Furthermore, in the RE-USY molecular sieve, the average size of the crystal grains is 0.3–1.2 μm, preferably 400–600 nm.

[0044] Furthermore, the unit cell constant of the RE-USY molecular sieve is

[0045] Furthermore, in the RE-USY molecular sieve, the SiO2 / Al2O3 molar ratio is 8.0 to 35.0, preferably 15.0 to 20.0.

[0046] Furthermore, the properties of the RE-USY molecular sieve are as follows: the ratio of Brønsted acid to Lønsted acid is 1.25 to 1.50 at 200℃, and the ratio of Brønsted acid to Lønsted acid is 1.10 to 1.30 at 350℃.

[0047] Furthermore, in the RE-USY molecular sieve, the total acid content is 420-500 μmol / g at 200℃ and 130-150 μmol / g at 350℃.

[0048] A third aspect of the present invention provides the application of the above-described RE-USY molecular sieve in hydrocracking catalysts.

[0049] Furthermore, the application is to use RE-USY molecular sieves in the manufacture of flexible hydrocracking catalysts.

[0050] Furthermore, the hydrocracking catalyst comprises RE-USY molecular sieve and a hydrocracking active metal component. The hydrocracking active metal is preferably a Group VIB or Group VIII metal, more preferably molybdenum, tungsten, or nickel. Based on the weight of the catalyst, the content of RE-USY molecular sieve is 15.0%-45.0%, the content of molybdenum (calculated as oxide) is 8.0%-18.0%, the content of tungsten (calculated as oxide) is 2.0%-10.0%, and the content of nickel (calculated as oxide) is 3.0%-8.0%.

[0051] Furthermore, the hydrocracking catalyst also includes alumina, with the alumina content ranging from 40% to 75% based on the weight of the catalyst.

[0052] Furthermore, the hydrocracking catalyst is particularly suitable for the catalytic cracking of polycyclic macromolecules. The feedstock can be vacuum gas oil with an initial boiling point of 345-375℃ and a final boiling point of 510-550℃. The main target products are heavy naphtha and jet fuel.

[0053] Furthermore, before use, the hydrogenation catalyst can be pre-sulfurized according to conventional methods in the art. The pre-sulfurization method can be: pre-sulfurizing the hydrogenation catalyst with sulfur, hydrogen sulfide or sulfur-containing raw materials in the presence of hydrogen at 165-320°C.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] The conventional Y molecular sieve framework is relatively stable, and the number of mesopores formed by hydrothermal treatment is still very limited. Moreover, during the hydrothermal treatment process, the removal of framework aluminum will cause the loss of acidic centers of the Y molecular sieve, and its reactivity will decrease.

[0056] The modified Y-zeolite of this invention differs from previous post-processing modified Y-zeolites. Instead, boron (B) is first introduced into the guiding agent during Y-zeolite synthesis to form crystal nuclei containing unstable "sites." Then, B is introduced again into the matrix solution used for Y-zeolite synthesis. This "two-step method" controls both the nucleation and crystal growth processes, making the modification effect of heteroatoms (B) on the Y-zeolite more pronounced. The inherent properties of B atoms can be fully utilized to promote framework instability. Finally, rare earth ions are introduced during the first ammonium exchange process, effectively removing... Sodium ions, which are difficult to remove from the Y molecular sieve, are reduced in content, increasing the mesopore ratio. On the other hand, rare earth ions coordinate with water molecules during hydrothermal treatment. Due to their high valence, water molecules polarize, generating a large number of hydroxide ions. These hydroxide ions are attracted by rare earth ions, producing a large number of free hydrogen ions. These hydrogen ions form structural hydroxyl groups with framework oxygen, increasing the Brønsted acid content. Simultaneously, rare earth ions also inhibit the removal of framework aluminum to some extent, reducing the amount of non-framework aluminum and thus increasing the B / L ratio. Finally, combined with dealumination during hydrothermal treatment, this significantly promotes the formation of mesopores in the Y molecular sieve, thereby greatly increasing the proportion of mesopores in the total pore volume and improving the overall performance of the Y molecular sieve. When this modified Y molecular sieve is used as a hydrocracking catalyst, it exhibits better adsorption, diffusion, and shape selectivity, improving reactivity and selectivity.

[0057] The method of this invention can yield RE-USY-type molecular sieves with high silica-to-alumina ratio, large specific surface area, and large pore volume, which can be used as cracking components in hydrocracking catalysts. The flexible hydrocracking catalysts prepared from these sieves exhibit significantly improved activity and selectivity. Attached Figure Description

[0058] Figure 1 The image shows the XRD pattern of the RE-USY molecular sieve obtained in Example 1. Detailed Implementation

[0059] The technical solutions and effects of the present invention will be further illustrated below with reference to the embodiments, but the invention is not limited to the following embodiments.

[0060] In this invention, the amount of Brønsted acid, Lønsted acid, and total acid are obtained by pyridine adsorption infrared spectroscopy and calculated, with units of μmol / g. The total acid is the sum of the Brønsted acid and Lønsted acid. The total acid at 200°C is the sum of the Brønsted acid and Lønsted acid at 200°C, and the total acid at 350°C is the sum of the Brønsted acid and Lønsted acid at 350°C.

[0061] In this invention, the pore volume, pore distribution, most probable pore size, and specific surface area of ​​the molecular sieve are determined using a physical adsorption instrument via a low-temperature nitrogen adsorption-desorption method. The pore volume and pore size distribution are obtained using the BJH method, and the specific surface area is obtained using the BET method.

[0062] In this invention, X-ray diffraction (XRD) was used to determine the phase composition and cell constant of the molecular sieve, and the Breck-Flanigen formula was used to calculate the silicon-to-aluminum ratio of the molecular sieve. The experimental conditions were: CuKα radiation, tube voltage 40 kV, and tube current 40 mA.

[0063] In this invention, scanning electron microscopy is used to statistically analyze the particle size distribution of molecular sieves.

[0064] In this invention, the distillation range of heavy naphtha is 65–177°C, and the distillation range of jet fuel is 177–260°C.

[0065] In this invention, the yield of heavy naphtha refers to the mass ratio of heavy naphtha to fresh hydrocracking feedstock (vacuum oil) in the hydrocracking products, and the yield of jet fuel refers to the mass ratio of jet fuel to fresh hydrocracking feedstock in the hydrocracking products.

[0066] Example 1

[0067] (1) Preparation of B-containing Y molecular sieve guide: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, and the first silicon source is silica sol. The first aluminum source and the first alkali source are mixed and dissolved in water, then the first B source and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the B-containing Y molecular sieve guide. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, and the first silicon source as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the feed is 1:30:0.50:15:300. The standing temperature is 25℃, and the standing time is 22 hours.

[0068] (2) Preparation of matrix mixture; the second B source in the matrix mixture is sodium metaborate, the second aluminum source is sodium aluminate and aluminum sulfate (the molar ratio of sodium aluminate and aluminum sulfate, calculated as aluminum, is 1:0.52), the second alkali source is selected from NaOH, and the second silicon source is water glass. In the matrix solution, the second aluminum source is calculated as Al2O3, the second alkali source is calculated as NaOH, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the feed is 1:5.2:0.45:5.6:120. The amount of Y molecular sieve guide containing B added in step (1) is 15.0% of the total mass of the matrix mixture. The second B source is dissolved in the aqueous solution of the second aluminum source sodium aluminate, wherein the mass content of B (calculated as oxide) is 12.0%. After ultrasonic treatment (20kHz) for 4h and a standing process for 18h, the second B source feed is obtained. Mix the second alkali source and the second silicon source with the remaining water until homogeneous, then add the guide body obtained in step (1), the second B source feed, and the second aluminum source aluminum sulfate in sequence, mix them until homogeneous, and obtain a gel.

[0069] (3) The gel obtained in step (2) is subjected to crystallization treatment; the crystallization is carried out by three-stage temperature rise crystallization, with the first-stage crystallization temperature being 30℃, the second-stage crystallization temperature being 65℃, and the third-stage crystallization temperature being 100℃. The crystallization time for each stage is 18h.

[0070] (4) The crystallized product obtained in step (3) undergoes a first ammonium exchange and a first hydrothermal treatment to obtain a heteroatom-modified Y molecular sieve precursor. The ammonium salt used for ammonium exchange is ammonium nitrate, with a concentration of 0.1 mol / L. This solution contains 5.0% lanthanum chloride by mass of the molecular sieve solid to be exchanged, and the pH value is 6.8. The ammonium exchange temperature is 60℃, and the first ammonium exchange is performed once. The solid-liquid volume ratio for each ammonium exchange is 1:10, and the treatment time for each ammonium exchange is 6 hours. The hydrothermal treatment is performed once, and the conditions for each hydrothermal treatment are as follows: temperature is 620℃, 100% steam treatment, and treatment time is 6 hours. The steam treatment process is a flowing steam treatment.

[0071] (5) The precursor obtained in step (4) undergoes a second ammonium exchange and a second hydrothermal treatment to obtain the modified Y molecular sieve, namely RE-USY molecular sieve (its XRD is shown in the figure). Figure 1 ,Depend on Figure 1As can be seen, it exhibits diffraction peaks characteristic of Y-type molecular sieves. Ammonium exchange was performed using conventional methods. The ammonium salt used was ammonium nitrate, with a concentration of 0.1 mol / L and a pH of 6.8. The ammonium exchange temperature was 60℃, and the second ammonium exchange was performed once. The solid-liquid volume ratio for each ammonium exchange was 1:10, and the treatment time for each exchange was 6 hours. Hydrothermal treatment was performed once, under the following conditions: temperature 620℃, 100% steam treatment, and treatment time 6 hours. The steam treatment process used flowing steam.

[0072] In the molecular sieve obtained in Example 1, the content of La, calculated as La2O3, was 0.39%.

[0073] Example 2

[0074] (1) Preparation of B-containing Y-type molecular sieve guide: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, and the first silicon source is silica sol. The first aluminum source and the first alkali source are mixed and dissolved in water, then the first B source and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the B-containing Y-type molecular sieve guide. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, and the first silicon source as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the Y-type molecular sieve guide is 1:35:0.4:18:350. The standing temperature is 45℃, and the standing time is 28 hours.

[0075] (2) Preparation of matrix mixture; the second B source in the matrix mixture is ammonium fluoroborate, the second aluminum source is sodium aluminate and aluminum sulfate (the molar ratio of sodium aluminate and aluminum sulfate, calculated as aluminum, is 1:0.52), the second alkali source is selected from NaOH, and the second silicon source is water glass. In the matrix solution, the second aluminum source is calculated as Al2O3, the second alkali source is calculated as NaOH, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the feed is 1:4.8:0.4:6.2:180. The amount of Y molecular sieve guide containing B added in step (1) is 15.0% of the total mass of the matrix mixture. The second B source is dissolved in the aqueous solution of the second aluminum source sodium aluminate, wherein the mass content of B (calculated as oxide) is 14.0%. After ultrasonic treatment (25kHz) for 4 hours and a standing process for 18 hours, the second B source feed is obtained. Mix the second alkali source and the second silicon source with the remaining water until homogeneous, then add the guide body obtained in step (1), the second B source feed, and the second aluminum source aluminum sulfate in sequence, mix them until homogeneous, and obtain a gel.

[0076] (3) The gel obtained in step (2) is subjected to crystallization treatment; the crystallization is carried out by three-stage temperature rise crystallization, with the first-stage crystallization temperature being 30℃, the second-stage crystallization temperature being 65℃, and the third-stage crystallization temperature being 100℃. The crystallization time for each stage is 18h.

[0077] (4) The crystallized product obtained in step (3) undergoes a first ammonium exchange and a first hydrothermal treatment to obtain a heteroatom-modified Y molecular sieve precursor. The ammonium salt used for ammonium exchange is ammonium nitrate, with a concentration of 0.1 mol / L. This solution contains 7.0% lanthanum chloride by mass of the molecular sieve solid to be exchanged, and the pH value is 6.8. The ammonium exchange temperature is 60℃, and the first ammonium exchange is performed once. The solid-liquid volume ratio for each ammonium exchange is 1:10, and the treatment time for each ammonium exchange is 6 hours. The hydrothermal treatment is performed once, and the conditions for each hydrothermal treatment are as follows: temperature is 620℃, 100% steam treatment, and treatment time is 6 hours. The steam treatment process is a flowing steam treatment.

[0078] (5) The precursor obtained in step (4) undergoes a second ammonium exchange and a second hydrothermal treatment to obtain the modified Y molecular sieve, i.e., RE-USY molecular sieve. The ammonium salt used for ammonium exchange is ammonium nitrate, with a concentration of 0.1 mol / L and a pH of 6.8. The ammonium exchange temperature is 60℃, and the second ammonium exchange is performed once. The solid-liquid volume ratio for each ammonium exchange is 1:10, and the treatment time for each ammonium exchange is 6 hours. The hydrothermal treatment is performed once, and the conditions for each hydrothermal treatment are as follows: temperature is 620℃, 100% steam treatment, and treatment time is 6 hours. The steam treatment process is a flowing steam treatment.

[0079] In the molecular sieve obtained in Example 2, the content of La, calculated as La2O3, was 0.45%.

[0080] Example 3

[0081] (1) Preparation of B-containing Y molecular sieve guide: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, and the first silicon source is silica sol. The first aluminum source and the first alkali source are mixed and dissolved in water, then the first B source and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the B-containing Y molecular sieve guide. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, and the first silicon source as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the feed is 1:30:0.5:15:300. The standing temperature is 25℃, and the standing time is 22 hours.

[0082] (2) Preparation of matrix mixture; the second B source in the matrix mixture is sodium metaborate, the second aluminum source is sodium aluminate and aluminum sulfate (the molar ratio of sodium aluminate and aluminum sulfate, calculated as aluminum, is 1:0.52), the second alkali source is selected from NaOH, and the second silicon source is water glass. In the matrix solution, the second aluminum source is calculated as Al2O3, the second alkali source is calculated as NaOH, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the feed is 1:5.2:0.45:5.6:120. The amount of Y molecular sieve guide containing B added in step (1) is 10.0% of the total mass of the matrix mixture. The second B source is dissolved in the aqueous solution of the second aluminum source sodium aluminate, wherein the mass content of B is 16.0%. After ultrasonic treatment (30kHz) for 4h and a standing process for 12h, the second B source feed is obtained. Mix the second alkali source and the second silicon source with the remaining water until homogeneous, then add the guide body obtained in step (1), the second B source feed, and the second aluminum source aluminum sulfate in sequence, mix them until homogeneous, and obtain a gel.

[0083] (3) The gel obtained in step (2) is subjected to crystallization treatment; the crystallization is carried out by three-stage temperature rise crystallization, with the first-stage crystallization temperature being 30℃, the second-stage crystallization temperature being 65℃, and the third-stage crystallization temperature being 100℃. The crystallization time for each stage is 18h.

[0084] (4) The crystallized product obtained in step (3) undergoes a first ammonium exchange and a first hydrothermal treatment to obtain a heteroatom-modified Y molecular sieve precursor. The ammonium salt used for ammonium exchange is ammonium nitrate, with a concentration of 0.1 mol / L. This solution contains 9.0% lanthanum chloride by mass of the molecular sieve solid to be exchanged, and the pH value is 6.8. The ammonium exchange temperature is 60℃, and the first ammonium exchange is performed once. The solid-liquid volume ratio for each ammonium exchange is 1:10, and the treatment time for each ammonium exchange is 6 hours. The hydrothermal treatment is performed once, and the conditions for each hydrothermal treatment are as follows: temperature is 620℃, 100% steam treatment, and treatment time is 6 hours. The steam treatment process is a flowing steam treatment.

[0085] (5) The precursor obtained in step (4) undergoes a second ammonium exchange and a second hydrothermal treatment to obtain the modified Y molecular sieve, i.e., RE-USY molecular sieve. The ammonium salt used for ammonium exchange is ammonium nitrate, with a concentration of 0.1 mol / L and a pH of 6.8. The ammonium exchange temperature is 60℃, and the second ammonium exchange is performed once. The solid-liquid volume ratio for each ammonium exchange is 1:10, and the treatment time for each ammonium exchange is 6 hours. The hydrothermal treatment is performed once, and the conditions for each hydrothermal treatment are as follows: temperature is 620℃, 100% steam treatment, and treatment time is 6 hours. The steam treatment process is a flowing steam treatment.

[0086] In the molecular sieve obtained in Example 3, the content of La, calculated as La2O3, was 0.52%.

[0087] Example 4

[0088] (1) Preparation of B-containing Y molecular sieve guide: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, and the first silicon source is silica sol. The first aluminum source and the first alkali source are mixed and dissolved in water, then the first B source and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the B-containing Y molecular sieve guide. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, and the first silicon source as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the feed is 1:30:0.5:15:300. The standing temperature is 25℃, and the standing time is 22 hours.

[0089] (2) Preparation of matrix mixture; the second B source in the matrix mixture is sodium metaborate, the second aluminum source is sodium aluminate and aluminum sulfate (the molar ratio of sodium aluminate and aluminum sulfate, calculated as aluminum, is 1:0.5), the second alkali source is selected from NaOH, and the second silicon source is water glass. In the matrix solution, the second aluminum source is calculated as Al2O3, the second alkali source is calculated as NaOH, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the feed is 1:5.2:0.45:5.6:120. The amount of Y molecular sieve guide containing B added in step (1) is 15.0% of the total mass of the matrix mixture. The second B source is dissolved in the aluminum sulfate solution of the second aluminum source, wherein the mass content of B is 18.0%. After ultrasonic treatment (35kHz) for 4 hours and a standing process for 18 hours, the second B source feed is obtained. Mix the second alkali source and the second silicon source with the remaining water until uniform, and then add the guide body obtained in step (1), the second B source feed, and the second aluminum source sodium aluminate in sequence, mix them evenly, and obtain a gel.

[0090] (3) The gel obtained in step (2) is subjected to crystallization treatment; the crystallization is carried out by three-stage temperature rise crystallization, with the first-stage crystallization temperature at 40℃, the second-stage crystallization temperature at 75℃, and the third-stage crystallization temperature at 110℃. The crystallization time for each stage is 12h.

[0091] (4) The crystallized product obtained in step (3) undergoes a first ammonium exchange and a first hydrothermal treatment to obtain a heteroatom-modified Y molecular sieve precursor. The ammonium salt used for ammonium exchange is ammonium nitrate, with a concentration of 0.1 mol / L. This solution contains 11.0% lanthanum chloride by mass of the molecular sieve solid to be exchanged, and the pH value is 6.8. The ammonium exchange temperature is 60℃, and the first ammonium exchange is performed once. The solid-liquid volume ratio for each ammonium exchange is 1:10, and the treatment time for each ammonium exchange is 6 hours. The hydrothermal treatment is performed once, and the conditions for each hydrothermal treatment are as follows: temperature is 620℃, 100% steam treatment, and treatment time is 6 hours. The steam treatment process is a flowing steam treatment.

[0092] (5) The precursor obtained in step (4) undergoes a second ammonium exchange and a second hydrothermal treatment to obtain the modified Y molecular sieve, i.e., RE-USY molecular sieve. The ammonium salt used for ammonium exchange is ammonium nitrate, with a concentration of 0.1 mol / L and a pH of 6.8. The ammonium exchange temperature is 60℃, and the second ammonium exchange is performed once. The solid-liquid volume ratio for each ammonium exchange is 1:10, and the treatment time for each ammonium exchange is 6 hours. The hydrothermal treatment is performed once, and the conditions for each hydrothermal treatment are as follows: temperature is 620℃, 100% steam treatment, and treatment time is 6 hours. The steam treatment process is a flowing steam treatment.

[0093] In the molecular sieve obtained in Example 4, the content of La, calculated as La2O3, was 0.48%.

[0094] Example 5

[0095] (1) Preparation of B-containing Y molecular sieve guide: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, and the first silicon source is silica sol. The first aluminum source and the first alkali source are mixed and dissolved in water, then the first B source and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the B-containing Y molecular sieve guide. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, and the first silicon source as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the feed is 1:30:0.5:15:300. The standing temperature is 25℃, and the standing time is 22 hours.

[0096] (2) Preparation of matrix mixture; the second B source in the matrix mixture is sodium metaborate, the second aluminum source is sodium aluminate and aluminum sulfate (the molar ratio of sodium aluminate and aluminum sulfate, calculated as aluminum, is 1:0.52), the second alkali source is selected from NaOH, and the second silicon source is water glass. In the matrix solution, the second aluminum source is calculated as Al2O3, the second alkali source is calculated as NaOH, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the feed is 1:5.2:0.45:5.6:120. The amount of Y molecular sieve guide containing B added in step (1) is 15.0% of the total mass of the matrix mixture. The second B source is dissolved in the second silicon source water glass solution, wherein the mass content of B is 10.0%, and after ultrasonic treatment (40kHz) for 4h and a standing process, the standing time is 18h, to obtain the second B source feed. Mix the second alkali source with the remaining water until homogeneous, then add the guide body obtained in step (1), the second B source feed, the second aluminum source sodium aluminate, and the second aluminum source aluminum sulfate in sequence, mix until homogeneous, and obtain a gel.

[0097] (3) The gel obtained in step (2) is subjected to crystallization treatment; the crystallization is carried out by three-stage temperature rise crystallization, with the first-stage crystallization temperature being 30℃, the second-stage crystallization temperature being 65℃, and the third-stage crystallization temperature being 100℃. The crystallization time for each stage is 18h.

[0098] (4) The crystallized product obtained in step (3) undergoes a first ammonium exchange and a first hydrothermal treatment to obtain a heteroatom-modified Y molecular sieve precursor. The ammonium salt used for ammonium exchange is ammonium chloride, with a concentration of 0.1 mol / L. This solution contains 3.0% lanthanum chloride by mass of the molecular sieve solid to be exchanged, and the pH value is 5.2. The ammonium exchange temperature is 80℃, and the first ammonium exchange is performed once. The solid-liquid volume ratio for each ammonium exchange is 1:10, and the treatment time for each ammonium exchange is 4 hours. The hydrothermal treatment is performed once, and the conditions for each hydrothermal treatment are as follows: temperature is 600℃, 100% steam treatment, and treatment time is 4 hours. The steam treatment process is a flowing steam treatment.

[0099] (5) The precursor obtained in step (4) undergoes a second ammonium exchange and a second hydrothermal treatment to obtain the modified Y molecular sieve, i.e., RE-USY molecular sieve. The ammonium salt used for ammonium exchange is ammonium chloride, with a concentration of 0.1 mol / L and a pH of 5.2. The ammonium exchange temperature is 80℃, and the second ammonium exchange is performed once. The solid-liquid volume ratio for each ammonium exchange is 1:10, and the treatment time for each ammonium exchange is 4 hours. The hydrothermal treatment is performed once, and the conditions for each hydrothermal treatment are as follows: temperature is 600℃, 100% steam treatment, and treatment time is 4 hours. The steam treatment process is a flowing steam treatment.

[0100] In the molecular sieve obtained in Example 5, the content of La, calculated as La2O3, was 0.34%.

[0101] Example 6

[0102] (1) Preparation of B-containing Y molecular sieve guide: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, and the first silicon source is silica sol. The first aluminum source and the first alkali source are mixed and dissolved in water, then the first B source and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the B-containing Y molecular sieve guide. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, and the first silicon source as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the feed is 1:30:0.50:15:300. The standing temperature is 25℃, and the standing time is 22 hours.

[0103] (2) Preparation of matrix mixture; the second B source in the matrix mixture is sodium metaborate, the second aluminum source is sodium aluminate and aluminum sulfate (the molar ratio of sodium aluminate and aluminum sulfate, calculated as aluminum, is 1:0.52), the second alkali source is selected from NaOH, and the second silicon source is water glass. In the matrix solution, the second aluminum source is calculated as Al2O3, the second alkali source is calculated as NaOH, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O in the feed is 1:5.2:0.45:5.6:120. The amount of Y molecular sieve guide containing B added in step (1) is 15.0% of the total mass of the matrix mixture. The second B source is dissolved in water, where the mass content of B (calculated as oxide) is 12.0%. After ultrasonic treatment (20kHz) for 4 hours and a settling process for 18 hours, the second B source feed is obtained. Mix the second alkali source and the second silicon source with the remaining water until uniform, and then add the guide body obtained in step (1), the second B source feed, the second aluminum source sodium aluminate, and the second aluminum source aluminum sulfate in sequence, mix them evenly, and obtain a gel.

[0104] (3) The gel obtained in step (2) is subjected to crystallization treatment; the crystallization is carried out by three-stage temperature rise crystallization, with the first-stage crystallization temperature being 30℃, the second-stage crystallization temperature being 65℃, and the third-stage crystallization temperature being 100℃. The crystallization time for each stage is 18h.

[0105] (4) The crystallized product obtained in step (3) undergoes a first ammonium exchange and a first hydrothermal treatment to obtain a heteroatom-modified Y molecular sieve precursor. The ammonium salt used for ammonium exchange is ammonium nitrate, with a concentration of 0.1 mol / L. This solution contains 5.0% lanthanum chloride by mass of the molecular sieve solid to be exchanged, and the pH value is 6.8. The ammonium exchange temperature is 60℃, and the first ammonium exchange is performed once. The solid-liquid volume ratio for each ammonium exchange is 1:10, and the treatment time for each ammonium exchange is 6 hours. The hydrothermal treatment is performed once, and the conditions for each hydrothermal treatment are as follows: temperature is 620℃, 100% steam treatment, and treatment time is 6 hours. The steam treatment process is a flowing steam treatment.

[0106] (5) The precursor obtained in step (4) undergoes a second ammonium exchange and a second hydrothermal treatment to obtain the modified Y molecular sieve, i.e., RE-USY molecular sieve. The ammonium exchange is a conventional ammonium exchange. The ammonium salt used is ammonium nitrate, with a concentration of 0.1 mol / L and a pH of 6.8. The ammonium exchange temperature is 60℃, and the second ammonium exchange is performed once. The solid-liquid volume ratio for each ammonium exchange is 1:10, and the treatment time for each ammonium exchange is 6 hours. The hydrothermal treatment is performed once, and the conditions for each hydrothermal treatment are as follows: temperature is 620℃, 100% steam treatment, and treatment time is 6 hours. The steam treatment process is a flowing steam treatment.

[0107] In the molecular sieve obtained in Example 1, the content of La, calculated as La2O3, was 0.39%.

[0108] Example 7

[0109] The difference from Example 1 is that the water vapor treatment process in step (4) is a closed process.

[0110] Comparative Example 1

[0111] Compared with Example 1, the difference is that the Y molecular sieve guide prepared in step (1) does not contain the first B source, but only the first aluminum source, the first alkali source, the first silicon source and water are mixed and left to stand to obtain the Y molecular sieve guide.

[0112] Comparative Example 2

[0113] Compared with Example 1, the difference is that in step (2), the amount of Y molecular sieve guide containing B added to the matrix mixture is 8.0% of the total mass of the matrix solution.

[0114] Comparative Example 3

[0115] Compared with Example 1, the difference is that the three-stage temperature rise crystallization process was not used in step (3), but the crystallization temperature was 65°C for 54 hours.

[0116] Application examples

[0117] This invention provides examples of the application of molecular sieves in flexible hydrocracking catalysts: the molecular sieves, alumina, molybdenum oxide, tungsten oxide, nickel oxide and guar gum powder prepared in each example are mixed evenly in a certain proportion, an inorganic acid is added as a binder, the powder is uniformly rolled into shape, dried at 120°C for 4 hours, and then calcined at 500°C for 6 hours to obtain a hydrocracking catalyst, the properties of which are shown in Table 2. The catalyst numbers are A-1 to A-7 and D-1 to D-3 in sequence.

[0118] Catalyst Evaluation: The catalysts prepared above were evaluated using a 200 mL small-scale hydrocracking unit. The catalysts underwent a pre-sulfurization process before reaction. The properties of the feedstock used in the evaluation tests are shown in Table 3. The process conditions and reaction performance results of the evaluation tests are shown in Tables 4 and 5. When evaluating this flexible hydrocracking catalyst, the feedstock was sequentially passed through two beds: one for hydrorefining catalyst and the other for the flexible hydrocracking catalyst prepared above. During the hydrorefining catalyst bed, the organic nitrogen content in the feedstock was controlled to be less than 10 ppm.

[0119] Table 1. Properties of the molecular sieves prepared in each example.

[0120]

[0121] Continued in Table 1: Properties of the molecular sieves prepared in each example

[0122]

[0123] Table 2 Composition of hydrocracking catalyst

[0124]

[0125] Table 3 Properties of the feedstock oil used in the evaluation test

[0126] <![CDATA[Density (20 °C), g / cm 3 > 0.90 Distillation range, °C IBP / EBP 355 / 518 Pour point, ℃ 33 Residual carbon, wt% 0.22 S, wt% 1.4 N, wt% 0.16

[0127] Table 4. Process conditions and reaction performance results of the evaluation test of the catalyst of the present invention.

[0128]

[0129] Table 5. Process conditions and reaction performance results of the comparative catalyst evaluation test.

[0130]

[0131]

[0132] As shown in Tables 4 and 5, when the conversion rate of the controlled reaction is the same, the catalyst of the present invention exhibits better reaction activity and selectivity for the target product.

[0133] The embodiments described above are merely detailed descriptions of the technical solutions of the present invention, but the present invention is not limited to the above embodiments, that is, the present invention does not depend on the steps described in the above embodiments to be implemented. In summary, any improvements made to the present invention by those skilled in the art, including the substitution of the raw materials and additives described in the present invention, the selection of specific implementation methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A RE-USY molecular sieve, characterized in that: The molecular sieve contains rare earth elements, specifically one or more of lanthanum or cerium. The RE-USY molecular sieve exhibits the following properties: mesoporous pore volume accounts for 30% to 60% of the total pore volume; the specific surface area of ​​the RE-USY molecular sieve is 550 to 730 m². 2 / g, with a pore volume of 0.35~0.65mL / g; in the RE-USY molecular sieve, the SiO2 / Al2O3 molar ratio is 8.0~35.0; the ratio of Brønsted acid to Lewis acid in the RE-USY molecular sieve at 200℃ is 1.25~1.50, and the ratio of Brønsted acid to Lewis acid at 350℃ is 1.10~1.

30.

2. The molecular sieve according to claim 1, characterized in that: The RE-USY molecular sieve has the following properties: mesoporous pore volume accounts for 40% to 53% of the total pore volume of the molecular sieve.

3. The molecular sieve according to claim 1, characterized in that: The average size of the crystals in the RE-USY molecular sieve is 0.3~1.2μm; And / or, the cell constant of the RE-USY molecular sieve is 23.32~24.40 Å; And / or, in the RE-USY molecular sieve, the SiO2 / Al2O3 molar ratio is 15.0~20.0; And / or, in the RE-USY molecular sieve, the total acid content is 420~500μmol / g at 200℃ and 130~150μmol / g at 350℃.

4. The molecular sieve according to claim 3, characterized in that: The average size of the crystals in the RE-USY molecular sieve is 400~600nm.

5. The molecular sieve according to claim 1, characterized in that: In the RE-USY molecular sieve, based on the mass of the RE-USY molecular sieve, the content of rare earth elements, calculated as oxides, is 0.10%~1.50%.

6. A method for preparing the RE-USY molecular sieve according to any one of claims 1-5, comprising the following steps: (1) Preparation of B-containing Y molecular sieve guides; (2) The matrix mixture is mixed with the guide body from step (1) to obtain a gel; (3) Crystallize the gel from step (2); (4) The crystallized product obtained in step (3) is subjected to a first ammonium exchange and a first hydrothermal treatment to obtain a heteroatom-modified Y molecular sieve precursor; (5) The precursor obtained in step (4) undergoes a second ammonium exchange and a second hydrothermal treatment to obtain the modified Y molecular sieve, namely RE-USY molecular sieve; in, In step (4), the first ammonium exchange is carried out using a mixed solution of ammonium salt and rare earth compound for ion exchange; In step (1), the preparation method of the B-containing Y molecular sieve guide includes: mixing the first aluminum source, the first alkali source, the first B source, the first silicon source and water, and letting it stand to obtain the B-containing Y molecular sieve guide; In step (2), the matrix mixture is a second aluminum source, a second silicon source, a second B source, a second alkali source, and water; In step (2), the amount of Y molecular sieve guide containing B added is 10.0%~45.0% of the total mass of the matrix mixture; In step (3), the crystallization adopts a three-stage temperature-increasing crystallization. The first-stage crystallization temperature is 30~40℃, the second-stage crystallization temperature is 30~35℃ higher than the first-stage temperature, and the third-stage crystallization temperature is 25~50℃ higher than the second-stage temperature, and the highest temperature does not exceed 110℃; the crystallization time for each stage is 12~36 hours.

7. The preparation method according to claim 6, characterized in that: The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, and the first silicon source as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O is 1:(11~42):(0.07~20.0):(5~25):(180~450). And / or, the standing temperature is 10~50℃, and the standing time is 15~35 hours.

8. The preparation method according to claim 7, characterized in that: The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, and the first silicon source as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O is 1:(15~35):(0.07~12.0):(5~18):(180~400).

9. The preparation method according to claim 6, characterized in that: In the matrix mixture, the second aluminum source is calculated as Al2O3, the second alkali source is calculated as NaOH, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O is 1:(1.5~15.0):(0.07~15.0):(1.5~12.0):(80~400).

10. The preparation method according to claim 9, characterized in that: In the matrix mixture, the second aluminum source is calculated as Al2O3, the second alkali source is calculated as NaOH, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:NaOH:B2O3:SiO2:H2O is 1:(1.5~10.0):(0.07~8.0):(1.5~8.0):(80~350).

11. The preparation method according to claim 6, characterized in that: In step (2), the second B source is introduced into the reaction system in the manner of feeding the second B source.

12. The preparation method according to claim 11, characterized in that: In step (2), the second B source feed is prepared using at least one of the following methods: a. At least a portion of the second B source and at least a portion of the second silicon source are used to form a second B source feed. b. At least a portion of the second B source and at least a portion of the second aluminum source are used to form the second B source feed. c. At least a portion of the second B source is fed with at least a portion of the second aluminum source and at least a portion of the second silicon source to form the second B source feed.

13. The preparation method according to claim 12, characterized in that: The second B source feed is ultrasonically treated and then allowed to stand before being introduced into the reaction system.

14. The preparation method according to claim 13, characterized in that: The settling time is 1 to 48 hours.

15. The preparation method according to claim 14, characterized in that: The settling time is 12-24 hours.

16. The preparation method according to claim 13, characterized in that: In the second B source feed, the mass content of B, calculated as oxides, is 2.0%~18.0%; And / or, the ultrasonic treatment conditions are as follows: temperature 20~80℃, ultrasonic frequency 20~45kHz, time 1~8h.

17. The preparation method according to claim 16, characterized in that: The ultrasonic treatment conditions are as follows: temperature 20~60℃, ultrasonic frequency 20~45kHz, time 1~4h.

18. The preparation method according to claim 6, characterized in that: The first B source or the second B source is independently selected from at least one of sodium metaborate, boric acid, ammonium fluoroborate, and borax; the first aluminum source or the second aluminum source is independently selected from at least one of sodium aluminate and aluminum sulfate; the first alkali source or the second alkali source is independently selected from at least one of NaOH and KOH; and the first silicon source or the second silicon source is independently selected from at least one of silica sol and water glass.

19. The preparation method according to claim 6, characterized in that: The crystallization time for each stage is 15 to 24 hours.

20. The preparation method according to claim 6, characterized in that: In step (4), the rare earth compound used for the first ammonium exchange is at least one of rare earth chloride and rare earth nitrate. And / or, the amount of rare earth compound added is 1.0% to 20.0% of the mass of the crystallized product obtained in step (3); And / or, the ammonium exchange pH is 1.0~7.0, the ammonium exchange temperature is 30~90℃, the number of ammonium exchanges is 1~5; the solid-liquid volume ratio of each ammonium exchange is 1:10~1:20, and the treatment time of each ammonium exchange is 3~6 hours.

21. The preparation method according to claim 20, characterized in that: The pH value for ammonium exchange is 2.0~7.0, and the temperature for ammonium exchange is 40~60℃.

22. The preparation method according to claim 6, characterized in that: The first hydrothermal treatment or the second hydrothermal treatment is selected independently from: the hydrothermal treatment is performed 1 to 3 times, and the conditions for each hydrothermal treatment are as follows: the temperature is 500 to 650°C, the treatment time is 1 to 6 hours under 100% water vapor treatment conditions.

23. The preparation method according to claim 22, characterized in that: The first hydrothermal treatment or the second hydrothermal treatment is selected independently: the hydrothermal treatment is performed twice, and the conditions for each hydrothermal treatment are as follows: the temperature is 500~650℃, the treatment time is 1~6 hours under 100% water vapor conditions.

24. The preparation method according to claim 22 or 23, characterized in that: The steam treatment is either a closed steam treatment or a flowing steam treatment.

25. The preparation method according to claim 24, characterized in that: The steam treatment is a flowing steam treatment.

26. The application of the RE-USY molecular sieve according to any one of claims 1-5 or the RE-USY molecular sieve prepared by any one of claims 6-25 in hydrocracking catalysts.

27. The application according to claim 26, characterized in that: RE-USY molecular sieves are used in the manufacture of flexible hydrocracking catalysts.

28. The application according to claim 26 or 27, characterized in that: The hydrocracking catalyst includes RE-USY molecular sieves and a hydrocracking active metal component, wherein the hydrocracking active metal is a Group VIB or Group VIII metal.

29. The application according to claim 28, characterized in that: The hydrogenation active metals are molybdenum, tungsten, and nickel.

30. The application according to claim 29, characterized in that: In the catalyst, based on the weight of the catalyst, the content of RE-USY molecular sieve is 15.0%-45.0%, the content of molybdenum as oxide is 8.0%-18.0%, the content of tungsten as oxide is 2.0%-10.0%, and the content of nickel as oxide is 3.0%-8.0%. And / or, the hydrocracking catalyst includes alumina, with an alumina content of 40%-75% based on the weight of the catalyst.

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