A USY molecular sieve, its preparation method and application

Abstract

This invention discloses a USY molecular sieve, its preparation method, and its applications. The USY molecular sieve has the following properties: mesoporous pore volume accounts for 35.0%–55.0% of the total pore volume of the molecular sieve, and the most probable pore size is 23–30 nm. When used as a hydrocracking catalyst, this USY molecular sieve exhibits better adsorption, diffusion, and shape selectivity, resulting in superior reaction performance.

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-type molecular sieves are widely used as the main cracking component in hydrocracking catalysts. Although the Y-type molecular sieves used in hydrocracking catalysts contain a certain amount of mesoporous structures, these mesoporous structures are not interconnected, and the mesoporous content is still insufficient. On the one hand, the polycyclic compounds used as feedstocks cannot fully utilize the abundant surface area of ​​the molecular sieves. On the other hand, after some feedstock molecules diffuse into the smaller mesopores and micropores, the cracking intermediates cannot diffuse out of the smaller channels in time, which will lead to over-cracking, increase the yield of light hydrocarbon components, accelerate carbon deposition in the channels, and catalyst deactivation.

[0003] CN101723399A discloses a method for preparing a framework of silica-rich Y molecular sieves. This method first pre-treats NaY molecular sieves with an alkaline solution to remove silica, then performs ammonium exchange and dealumination with silica replenishment on the alkali-treated sieves. The resulting Y molecular sieves exhibit an increase in mesopore size, but the increase is not significant.

[0004] Currently, there are many methods for modifying Y-zeolites, but they are basically conventional post-processing modifications. These methods have limited impact on the properties of Y-zeolites, as other atoms are difficult to integrate into the Y-zeolite framework. Microporous molecular sieves 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. Thus, constructing heteroatom-modified Y-zeolites during their synthesis and being able to regulate their properties can greatly simplify subsequent modification steps, leading to the preparation of higher-performance hydrocracking catalysts – a problem urgently needing 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. This USY molecular sieve significantly increases the proportion of mesoporous pores, exhibits better adsorption, diffusion, and shape selectivity, and is particularly suitable as an acidic component in hydrocracking molecular sieves. When preparing hydrocracking catalysts from this USY molecular sieve, it can improve reaction activity and selectivity.

[0006] The first aspect of the present invention provides a USY molecular sieve, wherein the USY molecular sieve has the following properties: the mesopore volume accounts for 35.0% to 55.0% of the total pore volume of the molecular sieve, preferably 38.0% to 55.0%, and the most probable pore size is 23 to 30 nm.

[0007] Furthermore, the properties of the USY molecular sieve are as follows: specific surface area of ​​600–750 m² / g. 2 / g, with a pore volume of 0.320~0.550mL / g.

[0008] Furthermore, in the USY molecular sieve, the average size of the crystal grains is 0.4–1.5 μm, preferably 400–600 nm.

[0009] Furthermore, the unit cell constant of the USY molecular sieve is

[0010] Furthermore, in the USY molecular sieve, the SiO2 / Al2O3 molar ratio is 7.0 to 27.5, preferably 13.0 to 16.0.

[0011] A second aspect of this invention provides a method for preparing Y-molecule sieves, comprising the following steps:

[0012] (1) Preparation of B-containing Y molecular sieve guide bodies;

[0013] (2) The matrix mixture is mixed with the guide body from step (1) to obtain a gel;

[0014] (3) The gel from step (2) is crystallized to obtain Y molecular sieve.

[0015] A third aspect of this invention provides a method for preparing USY molecular sieves, comprising the following steps:

[0016] (1) Preparation of B-containing Y molecular sieve guide bodies;

[0017] (2) The matrix mixture is mixed with the guide body from step (1) to obtain a gel;

[0018] (3) Crystallize the gel from step (2);

[0019] (4) The crystallized product obtained in step (3) is subjected to ammonium exchange and hydrothermal treatment to obtain heteroatom modified Y molecular sieve, namely B-USY molecular sieve.

[0020] 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.

[0021] 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).

[0022] 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.

[0023] Further, in step (1), in the method for preparing the Y molecular sieve guide containing B, 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 Y molecular sieve guide containing B.

[0024] 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.

[0025] 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.

[0026] 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).

[0027] 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.

[0028] 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:

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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%. Specifically, the second B source feed is ultrasonically treated and then allowed to stand (preferably, the standing 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 15 to 45 kHz, and time 1 to 8 hours, more preferably 1 to 4 hours.

[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. 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.

[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. 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.

[0035] 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.

[0036] Furthermore, in step (3), the resulting crystallized product, namely B-NaY molecular sieve, has a B2O3 / Al2O3 molar ratio of 0.045 to 0.150.

[0037] 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.

[0038] 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.

[0039] Furthermore, the properties of the USY molecular sieve are as follows: the mesoporous pore volume accounts for 35.0% to 55.0% of the total pore volume of the molecular sieve, preferably 38.0% to 55.0%, and the most probable pore size is 23 to 30 nm.

[0040] Furthermore, the properties of the USY molecular sieve are as follows: specific surface area of ​​600–750 m² / g. 2 / g, with a pore volume of 0.320~0.550mL / g.

[0041] Furthermore, in the USY molecular sieve, the average size of the crystal grains is 0.4–1.5 μm, preferably 400–600 nm.

[0042] Furthermore, the unit cell constant of the USY molecular sieve is

[0043] Furthermore, in the USY molecular sieve, the SiO2 / Al2O3 molar ratio is 7.0 to 27.5, preferably 13.0 to 16.0.

[0044] The fourth aspect of the present invention provides the application of the above-described USY molecular sieve in hydrocracking catalysts.

[0045] Furthermore, the application is to use USY molecular sieves in the manufacture of flexible hydrocracking catalysts.

[0046] 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, and more preferably molybdenum, tungsten, and nickel. Based on the weight of the catalyst, the content of USY molecular sieve is 25.0%-55.0%, the content of molybdenum (calculated as oxide) is 2.0%-8.0%, the content of tungsten (calculated as oxide) is 10.0%-18.0%, and the content of nickel (calculated as oxide) is 2.0%-8.0%.

[0047] Furthermore, the hydrocracking catalyst also includes alumina, with the alumina content ranging from 30% to 75% based on the weight of the catalyst.

[0048] 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 360-370℃ and a final boiling point of 520-530℃. The main target products are heavy naphtha and jet fuel.

[0049] 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 170-320°C.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] Conventional Y-type molecular sieves have a relatively stable framework, and even hydrothermal treatment results in a limited number of mesopores. The inventors discovered that introducing heteroatoms (B) into the Y-type molecular sieve framework during synthesis replaces some aluminum atoms. This increases the silicon-to-aluminum ratio of the Y-type molecular sieve. Furthermore, the shorter bond length and lower bond energy of the B-type bonds weaken the framework's stability, creating several "low-bond-energy points." Combined with subsequent hydrothermal treatment, these low-bond-energy points remove more framework aluminum, thus increasing the number of mesopores and improving the overall performance of the Y-type molecular sieve.

[0052] The USY molecular sieve of this invention differs from previous post-processing modified Y molecular sieves. Instead, boron (B) is first introduced into the guiding agent during Y molecular sieve synthesis to form crystal nuclei containing unstable "sites." Then, B is introduced again into the matrix solution used for Y molecular sieve synthesis. This "two-step method" controls both the nucleation and crystal growth processes, resulting in a more significant modification effect of heteroatoms (B) on the Y molecular sieve. The inherent properties of B atoms are fully utilized to promote framework instability. Finally, combined with the dealumination process in a hydrothermal manner, the generation of mesopores in the Y molecular sieve is significantly promoted, thereby greatly increasing the proportion of mesopores in the total pore volume of the Y molecular sieve. When this USY molecular sieve is used as a hydrocracking catalyst, it exhibits better adsorption, diffusion, and shape selectivity, resulting in superior reactivity.

[0053] The method of this invention can yield 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

[0054] Figure 1 The image shows the XRD pattern of the USY molecular sieve obtained in Example 1. Detailed Implementation

[0055] 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.

[0056] 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.

[0057] 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.

[0058] In this invention, scanning electron microscopy is used to statistically analyze the particle size distribution of molecular sieves.

[0059] In this invention, the distillation range of heavy naphtha is 65–177°C, and the distillation range of jet fuel is 177–260°C.

[0060] 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.

[0061] Example 1

[0062] (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.

[0063] (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 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 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 (frequency 25 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, and the second aluminum source, aluminum sulfate, are added in sequence and mixed evenly to obtain a gel.

[0064] (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.

[0065] (4) The crystallized product obtained in step (3) is subjected to ammonium exchange and hydrothermal treatment to obtain USY molecular sieve (its XRD is shown in Figure 3). 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 exchange was performed twice. The solid-liquid volume ratio for each exchange was 1:10, and the treatment time was 6 hours. Hydrothermal treatment was performed twice, with the following conditions: temperature 620℃, 100% steam, and treatment time of 6 hours. The steam treatment process used flowing steam.

[0066] Example 2

[0067] (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.

[0068] (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 (frequency 30kHz) for 3h 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) 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.

[0071] Example 3

[0072] (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.

[0073] (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 (frequency 35kHz) for 2 hours and a standing process for 12 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.

[0074] (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.

[0075] (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.

[0076] Example 4

[0077] (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.

[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 1:0.5), 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 aqueous solution of aluminum sulfate, the second aluminum source, where the mass content of B is 18.0%. After ultrasonic treatment (frequency 40kHz) for 1 hour and a standing process, the standing time is 18 hours, to obtain the second B source feed. 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.

[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 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.

[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] Example 5

[0082] (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.

[0083] (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 water glass solution of the second silicon source, wherein the mass content of B is 10.0%, and after ultrasonic treatment (frequency 20kHz) 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.

[0084] (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.

[0085] (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 2. 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.

[0086] Example 6

[0087] (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.

[0088] (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 (frequency 25kHz) 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.

[0089] (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.

[0090] (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.

[0091] Example 7

[0092] The difference from Example 1 is that the water vapor treatment process in step (4) is a closed process.

[0093] Comparative Example 1

[0094] 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.

[0095] Comparative Example 2

[0096] 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.

[0097] Comparative Example 3

[0098] 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.

[0099] Application examples

[0100] 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.

[0101] 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.

[0102] Table 1 shows the properties of the molecular sieves prepared in each example.

[0103]

[0104] Table 2 Composition of hydrocracking catalyst

[0105]

[0106]

[0107] Table 3 Properties of the feedstock oil used in the evaluation test

[0108] <![CDATA[Density (20 °C), g / cm 3 > 0.92 Distillation range, °C IBP / EBP 368 / 525 Pour point, ℃ 35 Residual carbon, wt% 0.26 S, wt% 1.5 N, wt% 0.14

[0109] Table 4. Process conditions and reaction performance results of the evaluation test of the catalyst of the present invention.

[0110]

[0111] Table 5. Process conditions and reaction performance results of the comparative catalyst evaluation test.

[0112]

[0113] As shown in Tables 4 and 5, while controlling the conversion rate of the reaction, the catalyst of the present invention exhibits better reaction activity and selectivity for the target product.

[0114] 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 USY molecular sieve, characterized in that: The properties of the USY molecular sieve are as follows: mesoporous pore volume accounts for 35.0%~55.0% of the total pore volume of the molecular sieve, and the most probable pore size is 23~30 nm; the preparation method of the USY molecular sieve includes 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 ammonium exchange and hydrothermal treatment to obtain USY molecular sieve; 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℃. In step (2), the matrix mixture comprises a second aluminum source, a second silicon source, a second B source, a second alkali source, and water; the second B source is introduced into the reaction system as a second B source feed, which is prepared by: at least a portion of the second B source and at least a portion of the second aluminum source being combined to form the second B source feed; in the second B source feed, the mass content of B, calculated as oxides, is 12.0%~18.0%; 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 (4), 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% steam treatment conditions; the steam treatment is a flowing steam treatment.

2. The molecular sieve according to claim 1, characterized in that: The properties of the USY molecular sieve are as follows: the mesoporous pore volume accounts for 38.0% to 55.0% of the total pore volume of the molecular sieve.

3. The molecular sieve according to claim 1, characterized in that: The properties of the USY molecular sieve are as follows: specific surface area of ​​600~750 m². 2 / g, pore volume is 0.320~0.550mL / g; And / or, in the USY molecular sieve, the average size of the crystals is 0.4~1.5μm; And / or, the unit cell constant of the USY molecular sieve is 23.30~24.40 Å; And / or, in the USY molecular sieve, the SiO2 / Al2O3 molar ratio is 7.0~27.

5.

4. The molecular sieve according to claim 1, characterized in that: In the USY molecular sieve, the average size of the crystals is 400~600nm; And / or, in the USY molecular sieve, the SiO2 / Al2O3 molar ratio is 13.0~16.

0.

5. A method for preparing the USY molecular sieve according to any one of claims 1-4, 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 ammonium exchange and hydrothermal treatment to obtain USY molecular sieve; 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℃. In step (2), the matrix mixture comprises a second aluminum source, a second silicon source, a second B source, a second alkali source, and water; the second B source is introduced into the reaction system as a second B source feed, which is prepared by: at least a portion of the second B source and at least a portion of the second aluminum source being combined to form the second B source feed; in the second B source feed, the mass content of B, calculated as oxides, is 12.0%~18.0%; 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 (4), 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% steam treatment conditions; the steam treatment is a flowing steam treatment.

6. The preparation method according to claim 5, characterized in that: 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.

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 5, characterized in that: The second aluminum source is calculated as Al2O3, the second alkali source as NaOH, the second B source as B2O3, and the second silicon source 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: The second aluminum source is calculated as Al2O3, the second alkali source as NaOH, the second B source as B2O3, and the second silicon source 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 5, characterized in that: The second source B feed is ultrasonically treated and then allowed to stand before being introduced into the reaction system.

12. The preparation method according to claim 11, characterized in that: The settling time is 1 to 48 hours.

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

14. The preparation method according to claim 11, characterized in that: The ultrasonic treatment conditions are as follows: temperature 20~80℃, ultrasonic frequency 15~45kHz.

15. The preparation method according to claim 14, characterized in that: The ultrasonic treatment conditions are as follows: temperature 20~60℃, time 1~4h.

16. The preparation method according to claim 5 or 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.

17. The preparation method according to claim 5, characterized in that: The crystallization time for each stage is 12 to 36 hours.

18. The preparation method according to claim 17, characterized in that: The crystallization time for each stage is 15 to 24 hours.

19. The use of the USY molecular sieve according to any one of claims 1-4 or the USY molecular sieve prepared by any one of claims 5-18 in hydrocracking catalysts.

20. The application according to claim 19, characterized in that: The USY molecular sieve is used in the manufacture of flexible hydrocracking catalysts.

21. The application according to claim 19 or 20, 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.

22. The application according to claim 21, characterized in that: The hydrogenation active metals are molybdenum, tungsten, and nickel.

23. The application according to claim 22, characterized in that: Based on the weight of the catalyst, the content of USY molecular sieve is 25.0%-55.0%, the content of molybdenum as oxide is 2.0%-8.0%, the content of tungsten as oxide is 10.0%-18.0%, and the content of nickel as oxide is 2.0%-8.0%. And / or, the hydrocracking catalyst includes alumina, with the alumina content being 30%-75% based on the weight of the catalyst.

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