A usy molecular sieve, its preparation and use

Abstract

This invention discloses a USY molecular sieve, its preparation, and its application. The USY molecular sieve has the following properties: mesoporous pore volume accounts for 30%–60% of the total pore volume; the total acid content is 400–480 μmol / g at 200℃ and 120–150 μmol / g at 350℃. When the molecular sieve of this invention is used as a hydrocracking catalyst, both the catalyst activity and selectivity are significantly improved.

Description

Technical Field

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

[0002] Hydrocracking catalysts are bifunctional catalysts, and Y-zeolite is widely used as a major cracking component in hydrocracking catalysts. However, the pore size of Y-zeolite is limited, and its reaction performance is restricted by the influence of its 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.

[0003] Currently, there are many methods for modifying Y-type molecular sieves, but they are basically conventional post-processing modifications. These methods have limited impact on the properties of Y-type molecular sieves, and it is difficult for other atoms to enter the Y-type molecular sieve framework. CN101723399A discloses a method for preparing framework-rich silica Y-type molecular sieves. This method first pre-treats NaY molecular sieves with alkaline solution for desilication, and then performs ammonium exchange, dealumination, and silica replenishment treatment on the alkaline-treated molecular sieve. The resulting Y-type molecular sieve has slightly increased mesopore size, but the increase is not significant. US5601798 discloses a method for preparing mesoporous Y-type molecular sieves. This method uses HY or USY as raw materials, mixes them in an autoclave with NH4NO3 solution or a mixed solution of NH4NO3 and HNO3, and treats them at 115–250℃ for 2–20 hours to obtain mesoporous Y-type molecular sieves. However, NH4NO3 solution or a mixture of NH4NO3 and HNO3 is an acidic solution. At high temperatures of 115–250°C, the solution generates its own pressure, and the dealuminization depth of the acid treatment increases significantly, resulting in a significant decrease in crystallinity and micropore volume.

[0004] In summary, how to construct heteroatom-modified Y molecular sieves during the synthesis of Y molecular sieves, thereby controlling the relevant properties of the molecular sieves, simplifying the modification steps of Y molecular sieves, and ultimately preparing hydrocracking catalysts with better performance is an urgent problem to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a USY molecular sieve, its preparation method, and its applications. When the molecular sieve of this invention is used as a hydrocracking catalyst, both the catalyst activity and selectivity are significantly improved.

[0006] The first aspect of the present invention provides a USY molecular sieve, wherein the properties of the 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 38% to 55%; the total acid content is 400 to 480 μmol / g at 200°C and 120 to 150 μmol / g at 350°C.

[0007] Furthermore, in the USY molecular sieve, the ratio of Brønsted acid to Leachate acid is 1.20–1.40 at 200°C and 1.10–1.25 at 350°C.

[0008] Furthermore, the most probable pore size in the USY molecular sieve is 23–30 nm.

[0009] Furthermore, the properties of the USY molecular sieve are as follows: specific surface area of ​​500–600 m² / g. 2 / g, with a pore volume of 0.350~0.410mL / g.

[0010] Furthermore, in the USY molecular sieve, the average size of the crystal grains is 0.4–1.4 μm, preferably 450–650 nm.

[0011] Furthermore, the unit cell constant of the USY molecular sieve is

[0012] Furthermore, in the USY molecular sieve, the SiO2 / Al2O3 molar ratio is 14.0 to 25.0.

[0013] A second aspect of this invention provides a method for preparing USY molecular sieves, comprising the following steps:

[0014] (1) Preparation of Y molecular sieve guides containing B and Mg;

[0015] (2) The second aluminum source, the second magnesium source, the second silicon source, the second B source, the second alkali source, and water are mixed with the guide body from step (1) to obtain a gel;

[0016] (3) Crystallize the gel from step (2);

[0017] (4) The crystallized product obtained in step (3) is subjected to ammonium exchange and hydrothermal treatment to obtain heteroatom modified Y molecular sieve, namely USY molecular sieve.

[0018] Further, in step (1), the preparation method of the Y molecular sieve guide containing B and Mg includes: mixing a first aluminum source, a first magnesium source, a first alkali source, a first B source, a first silicon source, and water, and allowing it to stand to obtain the Y molecular sieve guide containing B and Mg. 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 magnesium source is selected from at least one of magnesium nitrate, magnesium chloride, and magnesium 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.

[0019] Further, in step (1), in the method for preparing the Y molecular sieve guide containing B and Mg, the first aluminum source is calculated as Al2O3, the first magnesium source is calculated as MgO, the first alkali source is calculated as NaOH, the first B source is calculated as B2O3, and the first silicon source is calculated as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O is 1:0.1~5.0:11~42:0.07~20.0:5~25:180~450, preferably 1:0.1~3.0:15~35:0.07~12.0:5~18:180~400.

[0020] Furthermore, in step (1), in the preparation method of the Y molecular sieve guide containing B and Mg, the standing temperature is 10-50℃ and the standing time is 15-35 hours.

[0021] Further, in step (1), in the method for preparing the Y molecular sieve guide containing B and Mg, preferably, the first aluminum source, the first boron source and the first alkali source are mixed and dissolved in water, and then the first magnesium source and the first silicon source are added in sequence, mixed evenly, and allowed to stand to obtain the Y molecular sieve guide containing B.

[0022] Further, in step (2), the matrix mixture is a second aluminum source, a second magnesium source, a second silicon source, a second B source, a second alkali source, and water.

[0023] 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 magnesium source is selected from at least one of magnesium nitrate, magnesium chloride, and magnesium 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.

[0024] Further, in step (2), in the matrix mixture, the second aluminum source is calculated as Al2O3, the second magnesium source is calculated as MgO, 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:MgO:NaOH:B2O3:SiO2:H2O is 1:0.1~4.5:1.5~15.0:0.07~15.0:1.5~12.0:80~400, preferably 1:0.1~2.5:1.5~10.0:0.07~8.0:1.5~8.0:80~350.

[0025] Furthermore, in step (2), the amount of Y molecular sieve guide containing B and Mg added is 10.0% to 45.0% of the total mass of the matrix mixture.

[0026] 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:

[0027] 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.

[0028] 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.

[0029] 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.

[0030] Further, in step (2), the mass content of B (based on oxides) in the second B source feed is 2.0% to 18.0%, preferably 10.0% to 18.0%.

[0031] Further, in step (2), preferably, 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, and time 1 to 8 hours, more preferably 1 to 4 hours.

[0032] Further, in step (2), the matrix mixture (second aluminum source, second magnesium 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, the second aluminum source and the second magnesium source obtained in step (1) are added in sequence and mixed evenly to obtain a gel.

[0033] 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, the remaining second aluminum source, and the second magnesium 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.

[0034] 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.

[0035] Furthermore, in the crystallized product obtained in step (3), namely B-Mg-NaY molecular sieve, the content of Mg, calculated as MgO, is 1.0% to 1.5% based on B-Mg-NaY molecular sieve.

[0036] Further, in step (4), the 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.

[0037] Further, in step (4), the hydrothermal treatment is performed 1 to 3 times, preferably 2 times, and the conditions for each hydrothermal treatment 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.

[0038] Furthermore, in the USY molecular sieve, the mesoporous pore volume accounts for 30% to 60% of the total pore volume of the molecular sieve, preferably 38% to 55%.

[0039] Furthermore, in the USY molecular sieve, the total acid content is 400-480 μmol / g at 200℃ and 120-150 μmol / g at 350℃.

[0040] Furthermore, in the USY molecular sieve, the ratio of Brønsted acid to Leachate acid is 1.20–1.40 at 200°C and 1.10–1.25 at 350°C.

[0041] Furthermore, the most probable pore size in the USY molecular sieve is 23–30 nm.

[0042] Furthermore, the properties of the USY molecular sieve are as follows: specific surface area of ​​500–600 m² / g. 2 / g, with a pore volume of 0.350~0.410mL / g.

[0043] Furthermore, in the USY molecular sieve, the average size of the crystal grains is 0.4–1.4 μm, preferably 450–650 nm.

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

[0045] Furthermore, in the USY molecular sieve, the SiO2 / Al2O3 molar ratio is 14.0 to 25.0.

[0046] A third aspect of the present invention provides the application of the above-described USY molecular sieve in hydrocracking catalysts.

[0047] Furthermore, the application is to use USY molecular sieves in the manufacture of flexible hydrocracking catalysts.

[0048] Furthermore, the hydrocracking catalyst comprises a 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 the USY molecular sieve is 15.0%-40.0%, the content of molybdenum (calculated as oxide) is 8.0%-20.0%, the content of tungsten (calculated as oxide) is 2.0%-10.0%, and the content of nickel (calculated as oxide) is 2.0%-8.0%.

[0049] Furthermore, the hydrocracking catalyst also includes alumina, with the alumina content ranging from 40% to 75% based on the weight of the catalyst.

[0050] 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 350-365℃ and a final boiling point of 515-535℃. The main target products are heavy naphtha and jet fuel.

[0051] 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 160-315°C.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] Conventional Y-type molecular sieves have a relatively stable framework, and even hydrothermal treatment results in a limited number of mesopores. While combining single heteroatom-modified Y-type molecular sieves with hydrothermal treatment improves the pore structure to some extent, it also leads to the loss of acidic centers during the process. This invention employs a segmented introduction of dual heteroatoms. Heteroatom B is introduced as an auxiliary solvent, while Mg is directly introduced into the molecular sieve preparation process at appropriate times. This minimizes the competition between the two introduced atoms, allowing heteroatom B and Mg to synergistically modify the Y-type molecular sieve. Ultimately, this significantly increases the number of mesopores in the ultrastable Y-type molecular sieve and also significantly improves its acidity.

[0054] This invention introduces two heteroatoms (B and Mg) in stages into the synthesis of Y-zeolite. This promotes framework instability and, combined with hydrothermal treatment, increases the number of mesopores in the ultrastable Y-zeolite while compensating for the loss of acidic centers during dealumination. When this Y-zeolite is used in hydrocracking, it exhibits better adsorption, diffusion, and shape selectivity, resulting in superior reactivity.

[0055] The method of this invention can obtain USY molecular sieves with high silicon-to-aluminum ratio, large specific surface area, large pore volume, and specific acidity. The flexible hydrocracking catalyst prepared from it has significantly improved activity and selectivity. Attached Figure Description

[0056] Figure 1 The image shows the XRD pattern of the B-Mg-USY molecular sieve obtained in Example 1. Detailed Implementation

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] In this invention, scanning electron microscopy is used to statistically analyze the particle size distribution of molecular sieves.

[0062] In this invention, the distillation range of heavy naphtha is 65–177°C, and the distillation range of jet fuel is 177–260°C.

[0063] 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.

[0064] Example 1

[0065] (1) Preparation of Y-type molecular sieve guide containing B and Mg: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, the first magnesium source is magnesium chloride, 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, the first magnesium source, and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the Y-type molecular sieve guide containing B and Mg. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, the first magnesium source as MgO, and the first silicon source as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the feed is 1:0.35:30:0.50:15:300. The standing temperature is 25℃, and the standing time is 22 hours.

[0066] (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 magnesium source is selected from magnesium chloride, 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 magnesium source is calculated as MgO, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the feed is 1:0.30:5.2:0.45:5.6:120. The amount of Y molecular sieve guide containing B and Mg added in step (1) is 15.0% of the total mass of the matrix mixture. The second B source is dissolved in an aqueous solution of the second aluminum source, sodium aluminate, where the mass content of B (based on oxides) is 12.0%. After ultrasonic treatment (30 kHz) for 4 hours and a settling process of 18 hours, the second B source feed is obtained. The second alkali source and the second silicon source are mixed evenly with the remaining water, and then the guide body obtained in step (1), the second B source feed, the second aluminum source (aluminum sulfate), and the second magnesium source are added in sequence and mixed evenly to obtain a gel.

[0067] (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.

[0068] (4) The crystallized product obtained in step (3) (i.e., B-Mg-NaY molecular sieve) was subjected to ammonium exchange and hydrothermal treatment to obtain USY molecular sieve. The ammonium exchange was a conventional ammonium exchange. 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 ammonium exchange was performed twice. The solid-liquid volume ratio for each ammonium exchange was 1:10, and the treatment time for each ammonium exchange was 6 hours. The hydrothermal treatment was performed twice, and the hydrothermal treatment conditions for each time were as follows: temperature of 620℃, 100% steam treatment, and treatment time of 6 hours. The steam treatment process was a flowing steam treatment.

[0069] In the B-Mg-NaY molecular sieve obtained in Example 1, the Mg content, calculated as MgO, was 1.17%.

[0070] Example 2

[0071] (1) Preparation of Y-type molecular sieve guide containing B and Mg: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, the first magnesium source is magnesium chloride, 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, the first magnesium source, and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the Y-type molecular sieve guide containing B and Mg. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, the first magnesium source as MgO, and the first silicon source as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the Y-type molecular sieve guide is 1:0.35:35:0.4:18:350. The standing temperature is 45℃, and the standing time is 28 hours.

[0072] (2) Preparation of the 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 magnesium source is selected from magnesium chloride, 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 magnesium source is calculated as MgO, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the feed is 1:0.3:4.8:0.4:6.2:180. The amount of Y molecular sieve guide containing B and Mg added in step (1) is 15.0% of the total mass of the matrix mixture. The second B source is dissolved in an aqueous solution of the second aluminum source, sodium aluminate, where the mass content of B (based on oxides) is 14.0%. After ultrasonic treatment (35 kHz) for 4 hours and a settling process for 18 hours, the second B source feed is obtained. The second alkali source and the second silicon source are mixed evenly with the remaining water, and then the guide body obtained in step (1), the second B source feed, the second aluminum source (aluminum sulfate), and the second magnesium source are added in sequence and mixed evenly to obtain a gel.

[0073] (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.

[0074] (4) The crystallized product obtained in step (3) was subjected to ammonium exchange and hydrothermal treatment to obtain USY molecular sieve. The ammonium exchange was a conventional ammonium exchange. 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 ammonium exchange was performed twice. The solid-liquid volume ratio for each ammonium exchange was 1:10, and the treatment time for each ammonium exchange was 6 hours. The hydrothermal treatment was performed twice, and the hydrothermal treatment conditions for each time were as follows: temperature of 620℃, 100% steam treatment, and treatment time of 6 hours. The steam treatment process was a flowing steam treatment.

[0075] In the B-Mg-NaY molecular sieve obtained in Example 2, the Mg content, calculated as MgO, was 1.31%.

[0076] Example 3

[0077] (1) Preparation of Y-type molecular sieve guide containing B and Mg: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, the first magnesium source is magnesium chloride, 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, the first magnesium source, and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the Y-type molecular sieve guide containing B and Mg. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, the first magnesium source as MgO, and the first silicon source as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the feed is 1:0.35:30:0.5:15:300. The standing temperature is 25℃, and the standing time is 22 hours.

[0078] (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 magnesium source is selected from magnesium chloride, 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 magnesium source is calculated as MgO, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the feed is 1:0.30:5.2:0.45:5.6:120. The amount of Y molecular sieve guide containing B and Mg added in step (1) is 10.0% of the total mass of the matrix mixture. The second B source is dissolved in an aqueous solution of the second aluminum source, sodium aluminate, with a B mass content of 16.0%. After ultrasonic treatment (40 kHz) for 4 hours and a standing process for 12 hours, the second B source feed is obtained. The second alkali source and the second silicon source are mixed evenly with the remaining water, and then the guide body obtained in step (1), the second B source feed, the second aluminum source (aluminum sulfate), and the second magnesium source are added in sequence and mixed evenly to obtain a gel.

[0079] (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.

[0080] (4) The crystallized product obtained in step (3) was subjected to ammonium exchange and hydrothermal treatment to obtain USY molecular sieve. The ammonium exchange was a conventional ammonium exchange. 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 ammonium exchange was performed twice. The solid-liquid volume ratio for each ammonium exchange was 1:10, and the treatment time for each ammonium exchange was 6 hours. The hydrothermal treatment was performed twice, and the hydrothermal treatment conditions for each time were as follows: temperature of 620℃, 100% steam treatment, and treatment time of 6 hours. The steam treatment process was a flowing steam treatment.

[0081] In the B-Mg-NaY molecular sieve obtained in Example 3, the Mg content, calculated as MgO, was 1.22%.

[0082] Example 4

[0083] (1) Preparation of Y-type molecular sieve guide containing B and Mg: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, the first magnesium source is magnesium chloride, 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, the first magnesium source, and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the Y-type molecular sieve guide containing B and Mg. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, the first magnesium source as MgO, and the first silicon source as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the feed is 1:0.35:30:0.5:15:300. The standing temperature is 25℃, and the standing time is 22 hours.

[0084] (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 magnesium source is calculated as MgO, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the feed is 1:0.30:5.2:0.45:5.6:120. The amount of Y molecular sieve guide containing B and Mg added in step (1) is 15.0% of the total mass of the matrix mixture. The second B source is dissolved in an aqueous solution of the second aluminum source, aluminum sulfate, with a B mass content of 18.0%. After ultrasonic treatment (45 kHz) for 4 hours and a settling process for 18 hours, the second B source feed is obtained. The second alkali source and the second silicon source are mixed evenly with the remaining water, and then the guide body obtained in step (1), the second B source feed, the second aluminum source sodium aluminate, and the second magnesium source are added in sequence and mixed evenly to obtain a gel.

[0085] (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.

[0086] (4) The crystallized product obtained in step (3) was subjected to ammonium exchange and hydrothermal treatment to obtain USY molecular sieve. The ammonium exchange was a conventional ammonium exchange. 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 ammonium exchange was performed twice. The solid-liquid volume ratio for each ammonium exchange was 1:10, and the treatment time for each ammonium exchange was 6 hours. The hydrothermal treatment was performed twice, and the hydrothermal treatment conditions for each time were as follows: temperature of 620℃, 100% steam treatment, and treatment time of 6 hours. The steam treatment process was a flowing steam treatment.

[0087] In the B-Mg-NaY molecular sieve obtained in Example 4, the Mg content, calculated as MgO, was 1.28%.

[0088] Example 5

[0089] (1) Preparation of Y-type molecular sieve guide containing B and Mg: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, the first magnesium source is magnesium chloride, 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, the first magnesium source, and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the Y-type molecular sieve guide containing B and Mg. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, the first magnesium source as MgO, and the first silicon source as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the feed is 1:0.35:30:0.5:15:300. The standing temperature is 25℃, and the standing time is 22 hours.

[0090] (2) Preparation of the 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 magnesium source is calculated as MgO, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the feed is 1:0.30:5.2:0.45:5.6:120. The amount of Y molecular sieve guide containing B and Mg 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%. After ultrasonic treatment (25 kHz) for 4 hours and a standing process for 18 hours, the second B source feed is obtained. The second alkali source is mixed with the remaining water until homogeneous, and then the guide body obtained in step (1), the second B source feed, the second aluminum source sodium aluminate, the second aluminum source aluminum sulfate, and the second magnesium source are added in sequence and mixed until homogeneous to obtain a gel.

[0091] (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.

[0092] (4) The crystallized product obtained in step (3) was subjected to ammonium exchange and hydrothermal treatment to obtain USY molecular sieve. The ammonium exchange was a conventional ammonium exchange. The ammonium salt used was ammonium chloride, and the concentration of the ammonium salt solution was 0.1 mol / L with a pH of 5.2. The ammonium exchange temperature was 80℃, and the number of ammonium exchanges was 3. The solid-liquid volume ratio of each ammonium exchange was 1:10, and the treatment time for each ammonium exchange was 4 hours. The hydrothermal treatment was performed twice, and the hydrothermal treatment conditions for each time were as follows: temperature of 600℃, 100% steam treatment, and treatment time of 4 hours. The steam treatment process was a flowing steam treatment.

[0093] In the B-Mg-NaY molecular sieve obtained in Example 5, the Mg content, calculated as MgO, was 1.34%.

[0094] Example 6

[0095] (1) Preparation of Y-type molecular sieve guide containing B and Mg: The first B source is sodium metaborate, the first aluminum source is sodium aluminate, the first alkali source is NaOH, the first magnesium source is magnesium chloride, 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, the first magnesium source, and the first silicon source are added sequentially, mixed evenly, and allowed to stand to obtain the Y-type molecular sieve guide containing B and Mg. The first aluminum source is calculated as Al2O3, the first alkali source as NaOH, the first B source as B2O3, the first magnesium source as MgO, and the first silicon source as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the feed is 1:0.35:30:0.50:15:300. 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 magnesium source is selected from magnesium chloride, 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 magnesium source is calculated as MgO, the second B source is calculated as B2O3, and the second silicon source is calculated as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O in the feed is 1:0.30:5.2:0.45:5.6:120. The amount of Y molecular sieve guide containing B and Mg added in step (1) is 15.0% of the total mass of the matrix mixture. The second B source is dissolved in water, wherein the mass content of B (based on oxides) is 12.0%. After ultrasonic treatment (30 kHz) for 4 hours and a settling process of 18 hours, the second B source feed is obtained. The second alkali source and the second silicon source are mixed evenly with the remaining water, and then the guide body obtained in step (1), the second B source feed, the second aluminum source (sodium aluminate), the second aluminum source (aluminum sulfate), and the second magnesium source are added in sequence and mixed evenly to 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) (i.e., B-Mg-NaY molecular sieve) was subjected to ammonium exchange and hydrothermal treatment to obtain USY molecular sieve. The ammonium exchange was a conventional ammonium exchange. 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 ammonium exchange was performed twice. The solid-liquid volume ratio for each ammonium exchange was 1:10, and the treatment time for each ammonium exchange was 6 hours. The hydrothermal treatment was performed twice, and the hydrothermal treatment conditions for each time were as follows: temperature of 620℃, 100% steam treatment, and treatment time of 6 hours. The steam treatment process was a flowing steam treatment.

[0099] In the B-Mg-NaY molecular sieve obtained in Example 6, the Mg content, calculated as MgO, was 1.17%.

[0100] Example 7

[0101] The difference from Example 1 is that the water vapor treatment process in step (4) is a closed process.

[0102] Comparative Example 1

[0103] 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 magnesium source, the first alkali source, the first silicon source and water are mixed and left to stand to obtain the Y molecular sieve guide.

[0104] Comparative Example 2

[0105] Compared with Example 1, the difference is that in step (2), the amount of Y molecular sieve guide containing B and Mg added to the matrix mixture is 8.0% of the total mass of the matrix solution.

[0106] Comparative Example 3

[0107] 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.

[0108] Application examples

[0109] 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.

[0110] 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.

[0111] Table 1 shows the properties of the molecular sieves prepared in each example.

[0112]

[0113]

[0114] Continued in Table 1: Properties of the molecular sieves prepared in each example

[0115]

[0116] Table 2 Composition of hydrocracking catalyst

[0117]

[0118] Table 3 Properties of the feedstock oil used in the evaluation test

[0119] <![CDATA[Density (20 °C), g / cm 3 > 0.91 Distillation range, °C IBP / EBP 361 / 523 Pour point, ℃ 34 Residual carbon, wt% 0.23 S, wt% 1.6 N, wt% 0.12

[0120] Table 4. Process conditions and reaction performance results of the evaluation test of the catalyst of the present invention.

[0121]

[0122]

[0123] Table 5. Process conditions and reaction performance results of the comparative catalyst evaluation test (continued)

[0124]

[0125] 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.

[0126] 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 method for preparing USY molecular sieve, comprising the following steps: (1) Preparation of Y molecular sieve guides containing B and Mg; (2) The second aluminum source, the second magnesium source, the second silicon source, the second B source, the second alkali source, water and the guide body from step (1) are mixed to obtain a gel; (3) Crystallize the gel from step (2); (4) The crystallized product obtained in step (3) is subjected to ammonium exchange and hydrothermal treatment to obtain USY molecular sieve; In step (1), the preparation method of the Y molecular sieve guide containing B and Mg includes: The first aluminum source, the first magnesium source, the first alkali source, the first B source, the first silicon source and water are mixed and allowed to stand to obtain a Y molecular sieve guide containing B and Mg. In step (2), the amount of Y molecular sieve guide containing B and Mg added is 10.0% to 45.0% of the total mass of the matrix mixture, wherein the matrix mixture is a second aluminum source, a second magnesium source, a second silicon source, a second B source, a second alkali source and water; In step (3), the crystallization adopts a three-stage temperature rise 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℃.

2. The preparation method according to claim 1, characterized in that: The first aluminum source is calculated as Al2O3, the first magnesium source as MgO, the first alkali source as NaOH, the first B source as B2O3, and the first silicon source as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O is 1:0.1~5.0:11~42:0.07~20.0:5~25:180~450. And / or, the standing temperature is 10~50℃, and the standing time is 15~35 hours.

3. The preparation method according to claim 2, characterized in that: The first aluminum source is calculated as Al2O3, the first magnesium source as MgO, the first alkali source as NaOH, the first B source as B2O3, and the first silicon source as SiO2. The molar ratio of Al2O3:MgO:NaOH:B2O3:SiO2:H2O is 1:0.1~3.0:15~35:0.07~12.0:5~18:180~400.

4. The preparation method according to claim 1, characterized in that: In step (2), the second aluminum source is calculated as Al2O3, the second magnesium source is calculated as MgO, 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:MgO:NaOH:B2O3:SiO2:H2O is 1:0.1~4.5:1.5~15.0:0.07~15.0:1.5~12.0:80~400.

5. The preparation method according to claim 4, characterized in that: In step (2), the second aluminum source is calculated as Al2O3, the second magnesium source is calculated as MgO, 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:MgO:NaOH:B2O3:SiO2:H2O is 1:0.1~2.5:1.5~10.0:0.07~8.0:1.5~8.0:80~350.

6. The preparation method according to claim 1, characterized in that: 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 prepared by 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.

7. The preparation method according to claim 6, characterized in that: The second B source feed is ultrasonically treated and then allowed to stand before being introduced into the reaction system.

8. The preparation method according to claim 7, characterized in that: The second B source feed is ultrasonically treated and then left to stand for 1 to 48 hours.

9. The preparation method according to claim 8, characterized in that: The second B source feed is ultrasonically treated and then left to stand for 12-24 hours.

10. The preparation method according to claim 7, 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.

11. The preparation method according to claim 10, characterized in that: The ultrasonic treatment conditions are as follows: temperature 20~60℃, time 1~4h.

12. The preparation method according to claim 6, characterized in that: In step (2), 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, the remaining second aluminum source, and the second magnesium source are added in sequence and mixed evenly to obtain a gel.

13. The preparation method according to claim 1, 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 magnesium source or the second magnesium source is independently selected from at least one of magnesium nitrate, magnesium chloride, and magnesium sulfate; 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.

14. The preparation method according to claim 1, characterized in that: The crystallization time for each stage is 12 to 36 hours.

15. The preparation method according to claim 14, characterized in that: The crystallization time for each stage is 15 to 24 hours.

16. The preparation method according to claim 1, characterized in that: The hydrothermal treatment is performed 1 to 3 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.

17. The preparation method according to claim 16, characterized in that: The steam treatment is either a closed steam treatment or a flowing steam treatment.

18. The preparation method according to claim 17, characterized in that: The steam treatment is a flowing steam treatment.

19. The USY molecular sieve prepared by any one of the preparation methods described in claims 1-18.

20. The molecular sieve according to claim 19, characterized in that: The properties of the USY molecular sieve are as follows: the mesoporous pore volume accounts for 30% to 60% of the total pore volume of the molecular sieve; the total acid content is 400 to 480 μmol / g at 200℃ and 120 to 150 μmol / g at 350℃; in the USY molecular sieve, the ratio of Brønsted acid to Lewis acid is 1.20 to 1.40 at 200℃ and 1.10 to 1.25 at 350℃.

21. The molecular sieve according to claim 20, characterized in that: In the USY molecular sieve, mesopores account for 38% to 55% of the total pore volume of the molecular sieve.

22. The molecular sieve according to claim 20, characterized in that: The specific surface area of ​​the USY molecular sieve is 500~600 m². 2 / g, pore volume is 0.350~0.410mL / g; And / or, in the USY molecular sieve, the average size of the crystals is 0.4~1.4μm; And / or, the unit cell constant of the USY molecular sieve is 23.32~24.40 Å; And / or, in the USY molecular sieve, the SiO2 / Al2O3 molar ratio is 14.0~25.0; And / or, in the USY molecular sieve, the most probable pore size is 23~30nm.

23. The molecular sieve according to claim 20, characterized in that: The average size of the crystals in the USY molecular sieve is 450~650nm.

24. The use of the USY molecular sieve according to any one of claims 19-23 in a hydrocracking catalyst.

25. The application according to claim 24, characterized in that: USY molecular sieves are used in the manufacture of flexible hydrocracking catalysts.

26. The application according to claim 24 or 25, characterized in that: The hydrocracking catalyst includes a USY molecular sieve and a hydrocracking active metal component, wherein the hydrocracking active metal is a Group VIB or Group VIII metal.

27. The application according to claim 26, characterized in that: The hydrogenation active metals are molybdenum, tungsten, and nickel.

28. The application according to claim 27, characterized in that: In the catalyst, based on the weight of the catalyst, the content of USY molecular sieve is 15.0%-40.0%, the content of molybdenum as oxide is 8.0%-20.0%, the content of tungsten as oxide is 2.0%-10.0%, and the content of nickel as oxide is 2.0%-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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