Composite molecular sieve of AEL-configuration molecular sieve and beta-configuration molecular sieve as well as preparation method and application of composite molecular sieve

Abstract

The invention relates to a composite molecular sieve of an AEL-configuration molecular sieve and a beta-configuration molecular sieve, a preparation method of the composite molecular sieve and application of the composite molecular sieve in hydroisomerization. The preparation method of the composite molecular sieve comprises the following steps: providing a first molecular sieve containing a first template agent, and then preparing a second molecular sieve in the presence of a second template agent and the first molecular sieve containing the first template agent to obtain the composite molecular sieve, wherein the first template agent and the second template agent are different in chemical structure, and the first molecular sieve is an AEL configuration molecular sieve and the second molecular sieve is a beta configuration molecular sieve. When the composite molecular sieve is used as a catalyst, the content of a single branched chain isomer can be increased, and the yield of a target product is effectively improved.

Description

Technical Field

[0001] This invention relates to a molecular sieve, and more specifically to a composite molecular sieve of AEL-configured molecular sieve and beta-configured molecular sieve, its manufacturing method, and its application in hydroisomerization. Background Technology

[0002] With the rapid development of the automotive industry and increasingly stringent environmental protection requirements, the demand for high-end lubricants is growing, and the production of high-end lubricants requires high-quality Grade III and Grade III lubricants. + As a fundamental blending component, lubricating oil base oils are increasingly favored for their isomerization dewaxing technology, a key technology for producing high-end lubricating oil base oils. The core of isomerization dewaxing technology lies in the development of isomerization dewaxing catalysts, typically employing bifunctional catalysts composed of a metal active component with hydrodehydrogenation capabilities and an acidic component with skeletal isomerization capabilities. The metal active component usually utilizes Group VIII noble metals, while the acidic component primarily employs molecular sieves with one-dimensional pore structures and suitable acid properties. The acidic component of the molecular sieve is crucial for the isomerization dewaxing catalyst. Molecular sieves suitable for isomerization dewaxing reactions are typically one-dimensional straight-pore molecular sieves. Common types of molecular sieves suitable for isomerization dewaxing reactions include AEL-type molecular sieves, MTT-type molecular sieves, TON-type molecular sieves, and *MRE-type molecular sieves. The pore size can be selectively chosen based on the size of the alkane molecule. Furthermore, the acidity of the molecular sieve should not be too strong to facilitate rapid product desorption and prevent secondary isomerization and cracking side reactions caused by excessively strong molecular sieve adsorption forces that prevent product desorption from the active center.

[0003] While the pore structures of the aforementioned molecular sieves can satisfy the shape-selectivity requirement of allowing n-alkanes to freely enter and exit while preventing larger isoalkanes from entering, resulting in good shape-selectivity for reactions occurring within the pores, single-molecule sieve pore structures have certain limitations in terms of molecular adsorption and product diffusion. Their simple structure cannot effectively constrain products at the pore openings, easily leading to the formation of multi-branched isomers of non-target products. This results in low yields of isomerized products, low liquid yields, and product quality that needs further improvement. Composite molecular sieves, by coupling the pore structures and acidity of molecular sieves with different properties, can enhance the constraint on reactions, thus being more conducive to the formation of single-branched isomers of the target product.

[0004] Chinese patent CN107512725B discloses a core-shell structured TON-MFI composite molecular sieve and its preparation method. This composite molecular sieve is a core-shell molecular sieve formed by using MFI molecular sieve as the core and TON molecular sieve as the shell. This composite molecular sieve exhibits high crystallinity, dispersed particles, and regular morphology. Furthermore, the synthesis method is simple and does not involve cumbersome preparation steps. It combines ten-membered ring one-dimensional channels and Z-shaped channels, and the bonding method exposes more active sites on the pores. It can be used for various shape-selective catalytic reactions and has potential application value in fine chemicals, petrochemicals, and other fields.

[0005] Chinese patent CN112717995B discloses a composite molecular sieve catalyst of MCM-41 and SSZ-32. The composite molecular sieve consists of a microporous molecular sieve SSZ-32 as the core and a mesoporous molecular sieve MCM-41 as the shell. This composite molecular sieve has a significant acid gradient distribution, with stronger acidity in the internal micropores and weaker acidity in the external mesopores. The two work synergistically, thus exhibiting excellent performance in hydroisomerization catalysis. It improves the isomerization rate of n-alkanes and the yield of target products, reduces the occurrence of secondary reactions-cracking reactions, increases the yield of single-branched isomers, and is beneficial to improving catalytic activity, reducing carbon deposition, and extending catalyst life.

[0006] The inventors of this invention have discovered that when a single molecular sieve is applied to the isomerization reaction of long-chain alkanes, due to the weak pore constraint and the presence of many non-selective acidic centers, not only monomethyl branched isomers are generated during the isomerization process, but also over-isomerization occurs, resulting in the generation of more non-ideal polymethyl branched isomers. Summary of the Invention

[0007] Single-molecule sieve isomerization catalysts possess multiple active sites on their surface, but only the sites at the pore openings are selectively active. When n-alkanes undergo isomerization at the sieve pore openings to form monomethyl branched isomers, sufficient reaction space allows these isomers to further undergo isomerization to form polymethyl branched isomers. Furthermore, when diffused monomethyl branched isomers contact other non-selective active sites on the sieve surface, they also undergo isomerization to form polymethyl branched isomers.

[0008] The inventors of this invention have discovered that by covering the non-selective active sites on the surface of the molecular sieve, the occurrence of excessive isomerization can be suppressed; and by setting a local confinement structure at the pore opening of the molecular sieve, the monomethyl isomer is forced to leave immediately after its formation due to steric hindrance, thereby reducing its residence time at the pore opening and preventing further isomerization of the monomethyl branched isomer, which can significantly improve the selectivity of the monomethyl branched isomer.

[0009] According to a first embodiment of the present invention, a method for manufacturing a composite molecular sieve is provided, comprising the following steps: providing a first molecular sieve containing a first template agent (e.g., manufacturing the first molecular sieve containing the first template agent in the presence of the first template agent), and then manufacturing a second molecular sieve in the presence of a second template agent and the first molecular sieve containing the first template agent to obtain the composite molecular sieve, wherein the first template agent and the second template agent are chemically different, and the first molecular sieve is an AEL configuration molecular sieve (preferably SAPO-11 molecular sieve), and the second molecular sieve is a beta configuration molecular sieve (preferably an all-silica beta configuration molecular sieve).

[0010] According to a second embodiment of the present invention, a composite molecular sieve is provided, comprising a first molecular sieve and a second molecular sieve covering the surface of the first molecular sieve, wherein the first molecular sieve is an AEL configuration molecular sieve (preferably SAPO-11 molecular sieve), the second molecular sieve is a beta configuration molecular sieve (preferably all-silica beta configuration molecular sieve), and the mass ratio of the first molecular sieve to the second molecular sieve is (60-99):1, preferably (70-99):1, more preferably (80-99):1, and the outer surface acidity of the composite molecular sieve is 0.001 mmol / g-0.018 mmol / g (preferably 0.002 mmol / g-0.014 mmol / g).

[0011] According to a third embodiment of the present invention, a hydroisomerization catalyst (preferably a n-alkane hydroisomerization catalyst) is provided, comprising the composite molecular sieve and the active metal component of the present invention.

[0012] According to a fourth embodiment of the present invention, a hydroisomerization method (such as a dewaxing method for lubricating oil fractions) is provided, comprising the step of hydroisomerizing n-alkanes (such as paraffinic hydrocarbons) in the presence of the hydroisomerization catalyst of the present invention.

[0013] Technical effect

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] This invention utilizes the amphiphilicity of a combined template agent to grow pure silica beta molecular sieves on AEL molecular sieves, and forms a dual-microporous composite molecular sieve with two different pore sizes through the self-assembly of the template agent, creating a continuous "variable-diameter combined pore" structure. The AEL molecular sieve provides isomerization functionality, while the pure silica beta molecular sieve provides local confinement functionality. The pure silica beta molecular sieve reduces the acidity of the outer surface of the molecular sieve, thus ensuring that the isomerization reaction only occurs within the confined region. After straight-chain alkanes enter the isomer AEL molecular sieve and undergo isomerization at the pore opening to generate single-branched isomers, further isomerization is prevented due to the pore size constraint of the outer beta molecular sieve. This achieves the goal of controlling the degree of isomerization, increasing the content of single-branched isomers, and effectively improving the yield of the target product. Attached Figure Description

[0016] Figure 1 The images show the XRD patterns of the composite molecular sieve synthesized in Example 1.

[0017] Figure 2 These are the pore size distribution diagrams of the composite molecular sieve and SAPO-11 molecular sieve in Example 1 of the present invention.

[0018] Figure 3 The results are TEM characterization results of the composite molecular sieve synthesized in Example 1 of this invention. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in detail below. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims in the appendix.

[0020] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0021] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0022] In the context of this invention, all numerical values ​​of parameters (e.g., quantity or condition) should be understood to be modified by the term “about” in all cases, regardless of whether “about” actually appears before the numerical value.

[0023] In the context of this invention, "substantially" means that deviations that are acceptable or reasonable to those skilled in the art are permitted, such as deviations within ±2%, ±1%, ±0.5%, or ±0.1%.

[0024] In the context of this invention, the XRD spectrum is measured using a D / max-2500 fully automatic rotating target X-ray diffractometer. The experimental conditions are: Cu target, Kα radiation source, operating voltage 40kV, and tube current 80mA.

[0025] In the context of this invention, the method for measuring the composite structure formed by the first molecular sieve and the second molecular sieve is to use a JEM-2100 high-resolution transmission electron microscope from JEOL Corporation of Japan.

[0026] In the context of this invention, the type of the second molecular sieve is determined by XRD analysis of the powder obtained after lightly grinding the composite molecular sieve and sieving it. Specifically, the light grinding is performed by dry grinding using a mortar and pestle. To facilitate the detachment of the second molecular sieve from the surface of the carrier (first molecular sieve), the entire grinding process is conducted under relatively gentle conditions. The ground composite molecular sieve is then sieved through a mesh of 160 or finer, and the resulting powder (with a higher concentration of the second molecular sieve) is subjected to XRD analysis.

[0027] In the context of this invention, the pore size distribution is measured using an ASAP 2460 physical adsorption instrument via N2 adsorption-desorption method. Before measurement, the sample is activated by vacuuming at 300°C for 4 hours, and the pore size distribution is analyzed using a DFT model.

[0028] In the context of this invention, the average particle size is measured according to GB / T 6288-2021 Method for Determination of Particle Size of Granular Molecular Sieve.

[0029] In the context of this invention, the specific surface area, pore volume, and pore size are measured using an ASAP 2460 physical adsorption instrument via N2 adsorption-desorption method. Before measurement, the sample is activated by vacuuming at 300°C for 4 hours. The specific surface area of ​​the sample is calculated using the BET method, the pore volume is calculated using the BJH model, and the pore size distribution is analyzed using the DFT model.

[0030] In the context of this invention, the template agent content is measured by thermogravimetric analysis, and the weight loss at a temperature above 200°C until the weight loss curve stabilizes is taken as the template agent content of the molecular sieve.

[0031] In the context of this invention, the free water content is measured using a halogen moisture analyzer at a test temperature of 120°C for 10 minutes.

[0032] In the context of this invention, the method for measuring the template agent loss rate is to use thermogravimetric analysis. The weight loss at temperatures above 200°C until the weight loss curve stabilizes is taken as the template agent content. The template agent loss rate is calculated as follows: (template agent content in the molecular sieve before washing - template agent content in the molecular sieve after washing) / template agent content in the molecular sieve before washing * 100%.

[0033] In the context of this invention, the method for measuring the amount of acid on the outer surface is to use 2,6-di-tert-butylpyridine as a probe to determine its infrared spectrum of chemical desorption and calculate the amount of adsorption.

[0034] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this instruction manual are based on weight, and the pressure is gauge pressure.

[0035] In the context of this invention, any two or more embodiments or aspects of this invention can be arbitrarily combined, and the resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of this invention.

[0036] According to one embodiment of the present invention, a method for manufacturing a composite molecular sieve is provided, comprising step 1): providing a first molecular sieve containing a first template agent, for example, manufacturing the first molecular sieve containing the first template agent in the presence of the first template agent. Preferably, according to the present invention, the first molecular sieve containing the first template agent is substantially not removed after manufacturing. More preferably, the manufacturing method of the present invention does not include a step capable of removing part or all of the first template agent from the first molecular sieve containing the first template agent. The inventors of the present invention have found that if the first molecular sieve does not contain a template agent, or if a first molecular sieve without a template agent is added during the synthesis of a second molecular sieve, and a first template agent and a second template agent are added simultaneously, this situation leads to the inability to form a continuous pore structure between the first and second molecular sieves during the synthesis of the composite molecular sieve, severely restricting the diffusion of reactants and products. Since calcination can remove the template agent, according to a preferred embodiment of the present invention, step 1) does not include a calcination step.

[0037] According to one embodiment of the present invention, in step 1), an aluminum source, a silicon source, a phosphorus source and water are also present, wherein the molar ratio of the aluminum source (calculated as Al2O3): the phosphorus source (calculated as P2O5): the silicon source (calculated as SiO2): water: the first template agent is 1:0.6-1.4:0.02-1.2:30-100:0.3-2.0, preferably 1:0.7-1.2:0.08-0.8:40-80:0.6-1.8.

[0038] According to one embodiment of the present invention, the average particle size of the first molecular sieve containing the first template agent is 85% or more passing through 60 mesh, preferably 90% or more passing through 100 mesh. The inventors of the present invention have found that a suitable molecular sieve particle size is beneficial for the growth of a second molecular sieve on its surface; when the particle size is too large, it leads to a decrease in specific surface area, a reduction in the number of pores, an increase in free diffusion paths, and a decrease in catalytic activity.

[0039] According to one embodiment of the present invention, the free water content of the first molecular sieve containing the first template agent is no more than 10 wt%, preferably no more than 5 wt%. The inventors of the present invention have found that a lower water content can ensure the particle dispersion of the first molecular sieve. If the water content is too high, it will cause the dispersibility of the first molecular sieve to decrease, resulting in a viscous state, which will affect the growth of the second molecular sieve on its surface.

[0040] According to one embodiment of the present invention, based on the total weight of the first molecular sieve containing the first template agent as 100 wt%, the content of the first template agent is 3 wt%-40 wt%, preferably 6 wt%-35 wt%.

[0041] According to one embodiment of the present invention, after the first molecular sieve containing the first template agent is washed twice with deionized water at room temperature, the loss rate of the first template agent is less than 10 wt% (preferably less than 5 wt% or less than 2 wt%). According to the present invention, the first template agent is substantially entirely embedded within the pores of the first molecular sieve during its manufacturing process, and the interaction between the template agent and the first molecular sieve is not simply physical adsorption or physical mixing; therefore, the washing loss rate is very small.

[0042] According to one embodiment of the present invention, step 1) includes the following steps:

[0043] 1-1) A first mixture is formed by mixing a silicon source, an aluminum source, a phosphorus source, a first template agent, and water.

[0044] 1-2) Crystallize the first mixture to generate the first molecular sieve containing the first template agent.

[0045] 1-3) Separate the first molecular sieve containing the first template agent. Here, as a preferred embodiment of step 1-3), the first molecular sieve containing the first template agent is dried after optional washing and / or optional filtration.

[0046] According to one embodiment of the present invention, in step 1-2), the crystallization conditions include: crystallization pressure from atmospheric pressure to system autogenous pressure, presence or absence of seed crystals, crystallization temperature of 170℃-230℃ (preferably 180℃-220℃), and crystallization time of 12h-120h (preferably 24h-100h).

[0047] According to one embodiment of the present invention, in steps 1-3), the drying conditions include: a drying temperature of 60℃-180℃, preferably 80℃-180℃, and a drying time of 2h-20h, preferably 4h-15h. According to the present invention, there are no particular limitations on the drying process, but from the perspective of achieving superior technical effects, spray drying is particularly preferred. Therefore, the spray drying conditions include: a solid content of 35%-65%, an inlet air temperature of 150℃-250℃, an outlet air temperature of 80℃-150℃, and an air velocity of 300m / s. 3 / h-1500m 3 / h.

[0048] According to one embodiment of the present invention, after steps 1-3), the first molecular sieve containing the first template agent is further pulverized (e.g., ground) to an average particle size of 85% or more passing through 60 mesh, preferably 90% or more passing through 100 mesh.

[0049] According to one embodiment of the present invention, the method for manufacturing the composite molecular sieve includes step 2): then, a second molecular sieve is manufactured in the presence of a second template agent and the first molecular sieve containing the first template agent to obtain the composite molecular sieve.

[0050] According to the present invention, "then" means that step 2) must be performed after step 1). Specifically, the second molecular sieve is manufactured only after the first molecular sieve containing the first template agent is manufactured according to step 1). Therefore, according to the present invention, the first molecular sieve containing the first template agent and the second molecular sieve are not manufactured simultaneously. As a case of simultaneous manufacturing, for example, the first molecular sieve and the second molecular sieve can be manufactured simultaneously in the presence of the first template agent and the second template agent.

[0051] According to one embodiment of the present invention, in step 2), a silicon source, a fluorine source, an alkali source, and water are also present, wherein the silicon source (calculated as SiO2): the fluorine source (calculated as F) -1 (Calculated): The alkali source (in the form of OH) -1 The molar ratio of water to the second template agent is 1:0.2-2.5:0-0.5:5-40:0.05-0.8, preferably 1:0.3-2.0:0-0.4:6-36:0.1-0.6.

[0052] According to one embodiment of the present invention, in step 2), the mass ratio of the first molecular sieve containing the first template agent to the silicon source (in SiO2) in step 2) is (59-99):1, preferably (69-99):1, and more preferably (79-99):1.

[0053] According to a preferred embodiment of the present invention, from the perspective of obtaining a hydroisomerization catalyst with superior performance, the first molecular sieve is an AEL-configured molecular sieve (preferably SAPO-11 molecular sieve), and the second molecular sieve is a beta-configured molecular sieve (preferably an all-silica beta-configured molecular sieve). The inventors of the present invention have discovered that the acidity, pore size, and one-dimensional straight channels of SAPO-11 molecular sieve are suitable for long-chain alkane isomerization reactions, while the pore diameter of beta molecular sieves is around 0.67 nm, which can limit further reactions of monomethyl branched isomers and avoid the formation of multi-branched isomers.

[0054] According to the present invention, the first template agent and the second template agent are different in chemical structure. Preferably, the first template agent and the second template agent have similar polarities, which attracts them to each other, and both template agents contain nitrogen-containing functional groups, which then bond to each other through hydrogen bonds formed by the nitrogen-containing functional groups.

[0055] According to the present invention, "similar polarity" means that the first template agent and the second template agent have a small difference in molecular polarity. Specifically, if the two template agent molecules contain the same type and similar number of polar functional groups and the polar functional groups are relatively symmetrically positioned in the molecules, especially ammonium groups or substituted ammonium groups, or if the two template agents are mutually soluble or have a small difference in solubility in the same solvent (e.g., less than 20%), then they can be considered to have a small difference in molecular polarity.

[0056] According to the present invention, the first template agent can be used to synthesize the first molecular sieve. As a specific example, the first template agent is selected from at least one of di-n-propylamine, diisopropylamine, diethylamine, triethylamine, n-butylamine, di-n-butylamine, and diisobutylamine, preferably at least one of di-n-propylamine and diisopropylamine. Furthermore, the second template agent can be used to synthesize the second molecular sieve. As a specific example, the second template agent is selected from at least one of tetraethylammonium hydroxide, tetraethylammonium fluoride, triethylamine, tetrapropylammonium hydroxide, tetraethylammonium chloride, tetraethylammonium bromide, and tetraethylammonium iodide, preferably tetraethylammonium hydroxide.

[0057] According to one embodiment of the present invention, step 2) includes the following steps:

[0058] 2-1) A second mixture is formed by mixing a silicon source, a fluorine source, an alkali source, a second template agent, and water.

[0059] 2-2) Mix the first molecular sieve containing the first template agent with the second mixture to obtain a composite mixture.

[0060] 2-3) Optionally, after drying the composite mixture, crystallize the composite mixture to generate the composite molecular sieve.

[0061] 2-4) After optional washing and / or optional filtration, the composite molecular sieve is dried.

[0062] According to one embodiment of the present invention, in step 2-2), the second mixture is coated (e.g., sprayed) onto the first molecular sieve containing the first template agent in a finely granulated form.

[0063] According to one embodiment of the present invention, in step 2-2), the morphological integrity (particularly the bulk structure or pore structure) of the first molecular sieve containing the first template agent is substantially maintained after the mixing. In other words, the morphological integrity (particularly the bulk structure or pore structure) of the first molecular sieve containing the first template agent is substantially maintained under the manufacturing conditions of the second molecular sieve. Therefore, according to the present invention, the second molecular sieve is grown in situ on the first molecular sieve containing the first template agent. The inventors of the present invention have found that maintaining the morphological integrity of the first molecular sieve is beneficial to the permeability of the pore structure of the composite molecular sieve and also provides suitable active sites and reaction sites for isomerization reactions, which is beneficial to the diffusion of reactants and products. If the morphological integrity of the first molecular sieve is severely damaged, the second molecular sieve will be unable to grow on its surface, seriously affecting the confinement effect.

[0064] According to one embodiment of the present invention, in steps 2-3), drying is an optional step, but drying is preferred. The inventors of the present invention have discovered that the drying process allows the second molecular sieve precursor to form a dry gel on the surface of the first molecular sieve, which is more conducive to the subsequent crystallization process where the molecular sieve grows on its surface. Therefore, the drying conditions include: a drying temperature of 60℃-250℃, preferably 80℃-200℃, and a drying time of 0.1h-20h, preferably 4h-12h.

[0065] According to one embodiment of the present invention, in step 2-3), if the composite mixture is dried, the crystallization conditions include: crystallization pressure from atmospheric pressure to system autogenous pressure, water vapor concentration of 20%-70%, preferably 30%-50%, crystallization temperature of 120℃-200℃, preferably 140℃-180℃, and crystallization time of 24h-180h, preferably 30h-150h.

[0066] According to one embodiment of the present invention, in step 2-3), if the composite mixture has not been dried, the crystallization conditions include: crystallization pressure from atmospheric pressure to system autogenous pressure, crystallization temperature of 100℃-200℃, preferably 120℃-180℃, and crystallization time of 20h-150h, preferably 24h-80h.

[0067] According to one embodiment of the present invention, in steps 2-4), the drying conditions include: a drying temperature of 60℃-180℃, preferably 80℃-150℃, and a drying time of 2h-20h, preferably 4h-12h.

[0068] According to one embodiment of the present invention, the manufacturing method further includes a step of calcining the composite molecular sieve after steps 2-4), wherein the calcination conditions include: calcination temperature of 400℃-650℃ (preferably 450℃-600℃) under an oxygen-containing atmosphere, and calcination time of 3h-18h (preferably 4h-12h).

[0069] According to one embodiment of the present invention, there is no particular limitation on the silicon source, which can be any silicon source conventionally used in the manufacture of molecular sieves in the art, such as one or more of silica sol, fumed silica, water glass and organosilicone esters, preferably silica sol.

[0070] According to one embodiment of the present invention, there is no particular limitation on the aluminum source, which can be any aluminum source conventionally used in the manufacture of molecular sieves in the art. Specifically, one or more of aluminum hydroxide, boehmite, aluminum isopropoxide, aluminum sulfate and aluminum chloride can be cited, with aluminum hydroxide being preferred.

[0071] According to one embodiment of the present invention, there is no particular limitation on the phosphorus source, which can be any phosphorus source conventionally used in the manufacture of molecular sieves in the art. Specifically, one or more of phosphoric acid, phosphorous acid, hypophosphoric acid, ammonium phosphate, ammonium monohydrogen phosphate and ammonium dihydrogen phosphate can be mentioned, with phosphoric acid being preferred.

[0072] According to one embodiment of the present invention, there is no particular limitation on the fluorine source, which can be any fluorine source conventionally used in the manufacture of molecular sieves in the art, such as one or more of hydrofluoric acid, sodium fluoride and ammonium fluoride, preferably sodium fluoride.

[0073] According to one embodiment of the present invention, there is no particular limitation on the alkali source, which can be any alkali source conventionally used in the manufacture of molecular sieves in the art, such as sodium hydroxide or potassium hydroxide, preferably sodium hydroxide.

[0074] According to one embodiment of the present invention, a composite molecular sieve is disclosed, comprising a first molecular sieve and a second molecular sieve. According to the present invention, the composite molecular sieve can be manufactured according to the manufacturing method described in any of the foregoing or hereinafter described in this specification.

[0075] In the composite molecular sieve of the present invention, the first molecular sieve has a complete, smooth crystal structure, at least a portion of which is covered by a dense layer of the second molecular sieve. Preferably, the second molecular sieve densely covers substantially the entire surface of the first molecular sieve. The inventors of the present invention have discovered that as the coverage of the second molecular sieve on the surface of the first molecular sieve increases, the composite molecular sieve increasingly exhibits the surface properties of the second molecular sieve and increasingly loses the surface properties of the first molecular sieve, such as the amount of acid on its outer surface. In contrast, composite molecular sieves formed by directly coating the second molecular sieve onto the first molecular sieve according to the proportions specified in the present invention, or by simply physically mixing the two, still exhibit the surface properties of the first molecular sieve (e.g., the amount of acid on its outer surface); however, because the second molecular sieve occupies a relatively low proportion in the entire composite molecular sieve, its surface properties are difficult to measure. For example, the amount of acid on the outer surface of the composite molecular sieve is typically 0.001 mmol / g to 0.018 mmol / g (preferably 0.002 mmol / g to 0.014 mmol / g).

[0076] According to one embodiment of the present invention, the first molecular sieve is an AEL-configured molecular sieve (preferably SAPO-11 molecular sieve), the second molecular sieve is a beta-configured molecular sieve (preferably an all-silica beta-configured molecular sieve), and the mass ratio of the first molecular sieve to the second molecular sieve is (60-99):1, preferably (70-99):1, and more preferably (80-99):1. The composite molecular sieve formed by the present invention mainly consists of the second molecular sieve grown on the surface of the first molecular sieve. If the content of the second molecular sieve is too high, it will lead to an excessively high content of inactive components in the composite molecular sieve, resulting in a decrease in catalyst activity and covering the pore structure of the first molecular sieve, affecting the mass transfer process of the reactants and products.

[0077] According to one embodiment of the present invention, the average particle size of the first molecular sieve is 85% or more passing through 60 mesh (preferably 90% or more passing through 100 mesh).

[0078] According to the present invention, since the second molecular sieve accounts for a lower proportion in the entire composite molecular sieve, its contribution to the XRD pattern is smaller. Therefore, the XRD pattern of the composite molecular sieve is substantially the same as that of the first molecular sieve. If the relative intensity of the strongest characteristic diffraction peak in the XRD pattern is designated as 100, then vw = very weak (>0 to <10); w = weak (10 to ≤20); m = moderate (>20 to ≤40); s = strong (>40 to ≤60); vs = very strong (>60 to ≤100). Here, "substantially the same" means that the composite molecular sieve is consistent with the first molecular sieve at least on all characteristic diffraction peaks with relative intensities of s to vs (preferably m to vs). In other words, the composite molecular sieve substantially does not show characteristic diffraction peaks with relative intensities of s to vs associated with the second molecular sieve (when the second molecular sieve is measured alone), unless such characteristic diffraction peaks are shared by both the first and second molecular sieves. Based on the surface properties described above in this specification, and without any theoretical limitations, the inventors of this invention believe that the composite molecular sieve of this invention substantially exhibits the characteristics of the first molecular sieve in terms of bulk properties and substantially exhibits the characteristics of the second molecular sieve in terms of surface properties.

[0079] According to the present invention, the first molecular sieve and the composite molecular sieve have two distribution peaks in the micropore size distribution range: small pore size and large pore size. However, there is a significant difference in the number of pores between the two. Compared with the first molecular sieve, the number of small pores in the composite molecular sieve is reduced, while the number of large pores is increased. This is because after the second molecular sieve with a larger pore size is assembled onto the first molecular sieve, it covers part of the small pores on the surface of the first molecular sieve, thereby reducing the number of small pores. However, the reduction is small, resulting in the first molecular sieve and the second molecular sieve having essentially interconnected pores.

[0080] According to one embodiment of the present invention, the composite molecular sieve has a bimodal pore distribution. Specifically, the most probable pore sizes of the composite molecular sieve are 0.60 nm-0.66 nm (preferably about 0.62 nm) and 0.67 nm-0.72 nm (preferably about 0.69 nm). Preferably, the pores with the most probable pore size of 0.60 nm-0.66 nm account for more than 80% (preferably about 90%) of the total pore volume.

[0081] According to one embodiment of the present invention, the composite molecular sieve has a BET specific surface area of ​​160 m². 2 / g-450m 2 / g (preferably 200m) 2 / g-400m 2 / g), with a pore volume of 0.10ml / g-0.45ml / g (preferably 0.15ml / g-0.40ml / g).

[0082] According to one embodiment of the present invention, a hydroisomerization catalyst (preferably a n-alkane hydroisomerization catalyst) is provided, comprising the composite molecular sieve and active metal component described in any of the foregoing or hereinafter of this specification.

[0083] According to one embodiment of the present invention, based on a total weight of 100 wt% of the hydroisomerization catalyst, the content (dry basis) of the composite molecular sieve is 1 wt%-80 wt% (preferably 10 wt%-70 wt%, more preferably 20 wt%-60 wt%), and the content (based on metal element) of the active metal component is 0.01 wt%-10 wt% (preferably 0.05 wt%-8.0 wt%, more preferably 0.1 wt%-5.0 wt%).

[0084] According to one embodiment of the present invention, the active metal component is selected from at least one noble metal element of Group VIII of the periodic table, preferably at least one of Pt and Pd, especially Pt.

[0085] According to one embodiment of the present invention, a hydroisomerization method (such as a dewaxing method for lubricating oil fractions) is provided, comprising the step of hydroisomerizing n-alkanes (such as paraffinic hydrocarbons) in the presence of a hydroisomerization catalyst described in any of the foregoing or hereinafter of this specification.

[0086] According to one embodiment of the present invention, the conditions for the hydroisomerization reaction include: a reaction temperature of 250°C-420°C, a reaction pressure of 1.0 MPa-20 MPa, and a volume hourly space velocity of 0.5 h⁻¹. -1 -4.0h -1 The hydrogen-to-oil volume ratio is 500:1-1400:1.

[0087] According to one embodiment of the present invention, a molecular sieve precursor is disclosed, comprising a molecular sieve and a template agent, wherein the average particle size of the precursor is at least 85% passing through 60 mesh, preferably at least 90% passing through 100 mesh, and the free water content is no more than 10 wt%, preferably no more than 5 wt%. The template agent is selected from at least one of di-n-propylamine, diisopropylamine, diethylamine, tetraethylammonium hydroxide, and triethylamine, preferably at least one of di-n-propylamine and diisopropylamine. The molecular sieve is an AEL-configured molecular sieve (preferably SAPO-11 molecular sieve). According to the present invention, the molecular sieve precursor can be manufactured by the manufacturing method described above in this specification.

[0088] According to one embodiment of the present invention, after the precursor is washed twice with deionized water at room temperature, the loss rate of the template agent is less than 10 wt% (preferably less than 5 wt% or less than 2 wt%). According to the present invention, the template agent is substantially entirely embedded within the pores of the molecular sieve during the manufacturing process, and its interaction with the molecular sieve is not simply physical adsorption or physical mixing; therefore, the washing loss rate is very small.

[0089] According to one embodiment of the present invention, the content of the template agent is 3wt%-38wt%, preferably 6wt%-33wt%, based on a total weight of 100wt% of the precursor.

[0090] Example

[0091] The present invention will be further described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0092] In the following examples and comparative examples, the performance evaluation of the catalyst isomerization reaction was carried out using n-dodecane as a model compound. The catalyst was pre-reduced before feeding to convert the noble metal on the catalyst into a reduced state. The reduction conditions were as follows: in the presence of hydrogen, at a temperature of 400°C, a pressure of 4 MPa, and a time of 4 hours. The evaluation reaction conditions were as follows: in the presence of hydrogen, at a temperature of 250°C-420°C and a pressure of 4 MPa.

[0093] Example 1

[0094] (1) Mix 23.1g phosphoric acid (85wt%), 10.2g boehmite, 16.19g di-n-propylamine, 9g silica sol (30wt%) and 89g water evenly. After aging at room temperature for 3 hours, load the mixture into a crystallization kettle and heat it to 200℃ for dynamic hydrothermal crystallization for 45 hours. After crystallization, spray dry the crystallized product under the following conditions: solid content 40%, inlet air temperature 160℃, outlet air temperature 90℃, and inlet air volume 410m³. 3 / h, the main molecular sieve N1 is obtained, which is SAPO-11 molecular sieve.

[0095] The main molecular sieve N1 is not calcined, and its average particle size is more than 93% passing through 100 mesh, free water content is 2.8 wt%, template agent content is 14 wt%, and template agent loss rate is less than 3.2 wt%.

[0096] (2) Mix 3.26g tetraethylammonium hydroxide (35wt%), 0.31g sodium hydroxide, 3.88g silica sol (30wt%), 0.90g sodium fluoride and 7.38g water evenly, then spray it onto the main molecular sieve N1. After drying at 80℃ for 3h, a composite molecular sieve dry gel is obtained. Then, it is crystallized at 167℃ for 32h under the action of water vapor, dried at 80℃ for 12h and calcined at 450℃ for 5h to obtain a double microporous composite molecular sieve M1, which is a composite molecular sieve made by coating SAPO-11 molecular sieve with all-silica beta molecular sieve.

[0097] Figure 1 The XRD characterization results show that composite molecular sieve 1 is the composite molecular sieve prepared in this invention, and composite molecular sieve 2 is the composite molecular sieve after light grinding. Both mainly exhibit the characteristic diffraction peaks of SAPO-11 molecular sieve. The composite molecular sieve is identical to the first molecular sieve, SAPO-11, in all characteristic diffraction peaks with relative intensities from w to vs. Further comparative studies revealed that composite molecular sieve 2 exhibits weaker characteristic diffraction peaks of beta molecular sieve, thus confirming that the second molecular sieve is of beta type.

[0098] Figure 2 The results show the pore size distribution of the composite molecular sieve and the first molecular sieve. It can be seen that the composite molecular sieve has two distribution peaks: small pore size and large pore size. However, there is a significant difference in the number of pores between the two. Compared with the first molecular sieve, the increase in the number of large pores indicates the introduction of the second molecular sieve. In contrast, the number of small pores in the composite molecular sieve decreases, but the decrease is small, indicating that the pores of the first and second molecular sieves are basically interconnected.

[0099] TEM images revealed that the dual-microporous composite molecular sieve M1 comprises a first molecular sieve (SAPO-11 molecular sieve) and a second molecular sieve (all-silica beta molecular sieve) covering the surface of the first molecular sieve, such as... Figure 3 As shown. According to Figure 3 It can be seen that a dense crystalline material covers the original crystal surface of the first molecular sieve, SAPO-11, and there is a clear boundary between the two.

[0100] Measurements showed that the mass ratio of the first to the second molecular sieve in the dual-microporous composite molecular sieve M1 was 89:1. The channels of the first and second molecular sieves were essentially interconnected, and the XRD pattern of the composite molecular sieve was substantially the same as that of the first molecular sieve. The composite molecular sieve exhibited a bimodal pore distribution, with the most probable pore diameters being 0.62 nm and 0.69 nm, respectively. The most probable pore diameter of 0.62 nm accounted for 93% of the total pore volume. The BET specific surface area of ​​the composite molecular sieve was 258 m². 2 / g, pore volume is 0.23ml / g, and surface acidity is 0.005mmol / g.

[0101] (3) Take 80g of the prepared double microporous composite molecular sieve M1 (dry basis, the same below) and 35g of pseudoboehmite (dry basis) and mix them thoroughly. Add 1.8mL of concentrated nitric acid (mass fraction of 65%) and an appropriate amount of water, knead thoroughly, and then extrude into strips. Then, impregnate the noble metal Pt by the impregnation method. The Pt loading is 0.50wt% of the support. After drying at 90℃ for 5h and calcining at 470℃ for 4h, the catalyst C1 of this invention is obtained. The evaluation results of the catalyst are shown in Table 1.

[0102] Example 2

[0103] The synthesis of the composite molecular sieve and the preparation of the catalyst are the same as in Example 1, except that: the template agent used in the synthesis of the first molecular sieve is diisopropylamine, the mass ratio of the first molecular sieve to the second molecular sieve is 81:1, and the dual-microporous composite molecular sieve has a composite structure similar to that in Example 1, with an external surface acidity of 0.003 mmol / g. The catalyst is designated C2, and the evaluation results of the catalyst are shown in Table 1.

[0104] Example 3

[0105] The synthesis of the composite molecular sieve and the preparation of the catalyst are the same as in Example 1, except that the mass ratio of the first molecular sieve to the second molecular sieve is 97:1, and the dual-microporous composite molecular sieve has a composite structure similar to that in Example 1, with an external surface acidity of 0.012 mmol / g. The catalyst is designated C3, and the evaluation results are shown in Table 1.

[0106] Example 4

[0107] The synthesis of the composite molecular sieve and the preparation of the catalyst are the same as in Example 1, except that the mass ratio of the first molecular sieve containing the first template agent to the silicon source (calculated as SiO2) added during the synthesis of the second molecular sieve is 45:1. The dual-microporous composite molecular sieve has a composite structure similar to that in Example 1, and the acid content on the outer surface is 0.002 mmol / g. The catalyst is designated C4, and the evaluation results of the catalyst are shown in Table 1.

[0108] Example 5

[0109] The synthesis of the composite molecular sieve and the preparation of the catalyst are the same as in Example 1, except that the mass ratio of the first molecular sieve containing the first template agent to the silicon source (calculated as SiO2) added during the synthesis of the second molecular sieve is 120:1. The dual-microporous composite molecular sieve has a composite structure similar to that in Example 1, and the acid content on the outer surface is 0.014 mmol / g. The catalyst is designated C5, and the evaluation results of the catalyst are shown in Table 1.

[0110] Example 6

[0111] The synthesis of the composite molecular sieve and the preparation of the catalyst are the same as in Example 1, except that: the average particle size of the first molecular sieve containing the first template agent is 75% passing through 60 mesh; the dual-microporous composite molecular sieve has a composite structure similar to that in Example 1; and the acid content on the outer surface is 0.009 mmol / g. The catalyst is designated C6, and the evaluation results of the catalyst are shown in Table 1.

[0112] Example 7

[0113] The synthesis of the composite molecular sieve and the preparation of the catalyst are the same as in Example 1, except that the free water content of the first molecular sieve containing the first template agent is 15 wt%, and the dual-microporous composite molecular sieve has a composite structure similar to that in Example 1, with an external surface acidity of 0.013 mmol / g. The catalyst is designated C7, and the evaluation results are shown in Table 1.

[0114] Example 8

[0115] The synthesis of the composite molecular sieve and the preparation of the catalyst were the same as in Example 1, except that: after the first molecular sieve was crystallized, the product was subjected to ordinary drying at a temperature of 80°C for 3 hours. The dual-microporous composite molecular sieve had a composite structure similar to that in Example 1, with an external surface acidity of 0.007 mmol / g. The catalyst was designated C8, and the evaluation results are shown in Table 1.

[0116] Example 9

[0117] The synthesis of the composite molecular sieve and the preparation of the catalyst are the same as in Example 1, except that titanium tetrachloride is added instead of a silicon source during the synthesis of the first molecular sieve. The dual-microporous composite molecular sieve has a composite structure similar to that in Example 1, with an external surface acidity of 0.009 mmol / g. The catalyst is designated C9, and the evaluation results are shown in Table 1.

[0118] Example 10

[0119] The synthesis of the composite molecular sieve and the preparation of the catalyst are the same as in Example 1, except that: boehmite is added during the synthesis of the second molecular sieve, resulting in a composite molecular sieve formed by covering the surface of the SAPO-11 molecular sieve with an aluminum-containing beta molecular sieve. This dual-microporous composite molecular sieve has a similar composite structure to that of Example 1, with an outer surface acidity of 0.018 mmol / g. The catalyst is designated C10, and the evaluation results are shown in Table 1.

[0120] Example 11

[0121] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that: 0.6 g of sodium hydroxide was added to the raw material for the synthesis of the second molecular sieve, causing some of the first molecular sieve to be dissolved and destroyed. The resulting dual-microporous composite molecular sieve had a composite structure similar to that in Example 1, with an external surface acidity of 0.015 mmol / g. The catalyst was designated C11, and the evaluation results are shown in Table 1.

[0122] Example 12

[0123] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that no water vapor participated in the crystallization process of the second molecular sieve, and the dual-microporous composite molecular sieve had a composite structure similar to that in Example 1, with an external surface acidity of 0.008 mmol / g. The catalyst was designated C12, and the evaluation results are shown in Table 1.

[0124] Comparative Example 1

[0125] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that the first molecular sieve was directly SAPO-11 molecular sieve with the template agent removed after calcination, and the resulting composite molecular sieve had an outer surface acidity of 0.026 mmol / g. The catalyst was designated D1, and the evaluation results are shown in Table 1.

[0126] Comparative Example 2

[0127] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that 4.21 g of tetraethylammonium hydroxide (35 wt%) was added to the raw material for synthesizing the first molecular sieve, crystallized at 180 °C for 36 h, washed, dried, and calcined to obtain the composite molecular sieve. The surface acidity of the obtained composite molecular sieve was 0.044 mmol / g. The catalyst was designated D2, and the evaluation results are shown in Table 1.

[0128] Comparative Example 3

[0129] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that: the first molecular sieve was synthesized as a beta molecular sieve (SiO2 / Al2O3 = 60), and the second molecular sieve was synthesized as a SAPO-11 molecular sieve. The resulting composite molecular sieve was formed by covering the surface of the beta molecular sieve with SAPO-11 molecular sieve, and the surface acidity of the obtained composite molecular sieve was 0.088 mmol / g. The catalyst was designated as D3, and the evaluation results are shown in Table 1.

[0130] Comparative Example 4

[0131] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that the first molecular sieve was calcined after drying at 320℃ for 2 hours, resulting in an outer surface acidity of 0.024 mmol / g for the composite molecular sieve. The catalyst was designated D4, and the evaluation results are shown in Table 1.

[0132] Comparative Example 5

[0133] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that: the second molecular sieve, all-silica beta, was synthesized first, and then coated onto the first molecular sieve at a mass ratio of 1:92. The resulting composite molecular sieve had an outer surface acidity of 0.037 mmol / g. The catalyst was designated D5, and the evaluation results are shown in Table 1.

[0134] Table 1 Results of the hydroisomerization reaction of n-dodecane over a catalyst

[0135]

Claims

1. A method for manufacturing a composite molecular sieve, comprising the following steps: 1) Provide a first molecular sieve containing a first template agent (e.g., manufacture the first molecular sieve containing the first template agent in the presence of the first template agent), then 2) A second molecular sieve is manufactured in the presence of a second template agent and the first molecular sieve containing the first template agent to obtain the composite molecular sieve. The first template agent and the second template agent are different in chemical structure, and the first molecular sieve is an AEL configuration molecular sieve (preferably SAPO-11 molecular sieve), and the second molecular sieve is a beta configuration molecular sieve (preferably all-silica beta configuration molecular sieve).

2. The manufacturing method of claim 1, wherein in step 1), an aluminum source, a silicon source, a phosphorus source, and water are further present, wherein the molar ratio of the aluminum source (calculated as Al2O3): the phosphorus source (calculated as P2O5): the silicon source (calculated as SiO2): water: the first template agent is 1:0.6-1.4:0.02-1.2:30-100:0.3-2.0, preferably 1:0.7-1.2:0.08-0.8:40-80:0.6-1.8; and / or, in step 2), a silicon source, a fluorine source, an alkali source, and water are further present, wherein the molar ratio of the silicon source (calculated as SiO2): the fluorine source (calculated as P2O5 ... the first template agent is 1 -1 (Calculated): The alkali source (in OH-) -1 The molar ratio of water to the second template agent is 1:0.2-2.5:0-0.5:5-40:0.05-0.8, preferably 1:0.3-2.0:0-0.4:6-36:0.1-0.6; and / or, the mass ratio of the first molecular sieve containing the first template agent to the silicon source (calculated as SiO2) in step 2) is (59-99):1, preferably (69-99):1, more preferably (79-99):1; and / or, the average particle size of the first molecular sieve containing the first template agent is more than 85% passing through 60 mesh, preferably... More than 90% pass through 100 mesh; and / or, the free water content of the first molecular sieve containing the first template agent is no more than 10 wt%, preferably no more than 5 wt%; and / or, based on the total weight of the first molecular sieve containing the first template agent as 100 wt%, the content of the first template agent is 3 wt%-40 wt%, preferably 6 wt%-35 wt%; and / or, after washing the first molecular sieve containing the first template agent twice with deionized water at room temperature, the loss rate of the first template agent is less than 10 wt% (preferably less than 5 wt% or less than 2 wt%).

3. The manufacturing method of claim 1, wherein the first template agent and the second template agent have similar polarity and are able to form hydrogen bonds with each other in the presence of water, and / or, the first template agent can be used to synthesize the first molecular sieve, and / or, the first template agent is selected from at least one of di-n-propylamine, diisopropylamine, diethylamine, triethylamine, n-butylamine, di-n-butylamine, and diisobutylamine, preferably at least one of di-n-propylamine and diisopropylamine, and / or, the second template agent can be used to synthesize the second molecular sieve, and / or, the second template agent is selected from at least one of tetraethylammonium hydroxide, tetraethylammonium fluoride, triethylamine, tetrapropylammonium hydroxide, tetraethylammonium chloride, tetraethylammonium bromide, and tetraethylammonium iodide, preferably tetraethylammonium hydroxide.

4. The manufacturing method of claim 1, wherein step 1) comprises the following steps: 1-1) A first mixture is formed by mixing a silicon source, an aluminum source, a phosphorus source, a first template agent, and water. 1-2) Crystallize the first mixture to generate the first molecular sieve containing the first template agent. 1-3) Separate the first molecular sieve containing the first template agent (preferably, after optional washing and / or optional filtration, dry (especially spray dry) the first molecular sieve containing the first template agent).

5. The manufacturing method of claim 4, wherein in steps 1-2), the crystallization conditions include: The crystallization pressure is from atmospheric pressure to the system's autogenous pressure, with or without seed crystals; the crystallization temperature is 170℃-230℃ (preferably 180℃-220℃); the crystallization time is 12h-120h (preferably 24h-100h); and / or, in steps 1-3), the drying conditions include: a drying temperature of 60℃-180℃, preferably 80℃-180℃; a drying time of 2h-20h, preferably 4h-15h; and / or, in steps 1-3), the spray drying conditions include: a solid content of 35%-65%; an inlet air temperature of 150℃-250℃; an outlet air temperature of 80℃-150℃; and a wind speed of 300m / s. 3 / h-1500m 3 / h, and / or, further comprising, after steps 1-3), pulverizing (e.g., grinding) the first molecular sieve containing the first template agent to an average particle size of 85% or more passing through 60 mesh, preferably 90% or more passing through 100 mesh.

6. The manufacturing method of claim 1, excluding the step of removing part or all of the first template agent from the first molecular sieve containing the first template agent, and / or, wherein step 1) does not include a calcination step.

7. The manufacturing method of claim 1, wherein step 2) comprises the following steps: 2-1) A second mixture is formed by mixing a silicon source, a fluorine source, an alkali source, a second template agent, and water. 2-2) The first molecular sieve containing the first template agent is mixed with the second mixture to obtain a composite mixture. 2-3) Optionally, after drying the composite mixture, crystallize the composite mixture to generate the composite molecular sieve. 2-4) After optional washing and / or optional filtration, the composite molecular sieve is dried.

8. The manufacturing method of claim 7, wherein in step 2-2), the second mixture is finely coated (e.g., sprayed) onto the first molecular sieve containing the first template agent, and / or, in step 2-2), the morphological integrity (particularly the bulk structure or pore structure) of the first molecular sieve containing the first template agent is substantially maintained after the mixing.

9. The manufacturing method of claim 7, wherein in steps 2-3), the composite mixture is dried, and the crystallization conditions include: The crystallization pressure is from atmospheric pressure to the system's autogenous pressure; the water vapor concentration is 20%-70%, preferably 30%-50%; the crystallization temperature is 120℃-200℃, preferably 140℃-180℃; the crystallization time is 24h-180h, preferably 30h-150h; and / or, in steps 2-3), the composite mixture is not dried, and the crystallization conditions include: a crystallization pressure from atmospheric pressure to the system's autogenous pressure; a crystallization temperature of 100℃-200℃, preferably 120℃-180℃. The drying conditions include: 0℃, crystallization time of 20h-150h, preferably 24h-80h, and / or, in step 2-3), the drying conditions include: drying temperature of 60℃-250℃, preferably 80℃-200℃, drying time of 0.1h-20h, preferably 4h-12h, and / or, in step 2-4), the drying conditions include: drying temperature of 60℃-180℃, preferably 80℃-150℃, drying time of 2h-20h, preferably 4h-12h.

10. The manufacturing method of claim 7, further comprising, after steps 2-4), a step of calcining the composite molecular sieve, wherein the calcination conditions include: Under an oxygen-containing atmosphere, the calcination temperature is 400℃-650℃ (preferably 450℃-600℃), and the calcination time is 3h-18h (preferably 4h-12h).

11. The manufacturing method of claim 1, wherein in step 1), the first molecular sieve containing the first template agent is substantially not removed after manufacturing, and / or, in step 2), the morphological integrity (particularly the bulk structure or pore structure) of the first molecular sieve containing the first template agent is substantially maintained under the manufacturing conditions of the second molecular sieve, and / or, in step 2), the second molecular sieve is grown in situ on the first molecular sieve containing the first template agent.

12. A composite molecular sieve, comprising a first molecular sieve and a second molecular sieve covering the surface of the first molecular sieve, wherein the first molecular sieve is an AEL-configured molecular sieve (preferably SAPO-11 molecular sieve), the second molecular sieve is a beta-configured molecular sieve (preferably an all-silica beta-configured molecular sieve), and the mass ratio of the first molecular sieve to the second molecular sieve is (60-99):1, preferably (70-99):1, more preferably (80-99):1, and the outer surface acidity of the composite molecular sieve is 0.001 mmol / g-0.018 mmol / g (preferably 0.002 mmol / g-0.014 mmol / g).

13. The composite molecular sieve of claim 12, wherein the average particle size of the first molecular sieve is more than 85% passing through 60 mesh (preferably more than 90% passing through 100 mesh).

14. The composite molecular sieve of claim 12, wherein the first molecular sieve and the second molecular sieve are substantially interconnected in terms of pores, and / or, the XRD pattern of the composite molecular sieve is substantially the same as the XRD pattern of the first molecular sieve, and / or, the composite molecular sieve has a bimodal pore distribution, and / or, the most probable pore sizes of the composite molecular sieve are 0.60 nm-0.66 nm (preferably about 0.62 nm) and 0.67 nm-0.72 nm (preferably about 0.69 nm), respectively, and / or, the pores with the most probable pore size of 0.60 nm-0.66 nm account for more than 80% (preferably about 90%) of the total pore volume, and / or, the BET specific surface area of ​​the composite molecular sieve is 160 m². 2 / g-450m 2 / g (preferably 200m) 2 / g-400m 2 / g), with a pore volume of 0.10ml / g-0.45ml / g (preferably 0.15ml / g-0.40ml / g).

15. The composite molecular sieve of claim 12 can be manufactured according to the manufacturing method of any one of claims 1-11.

16. A hydroisomerization catalyst (preferably a n-alkane hydroisomerization catalyst) comprising the composite molecular sieve and active metal component as described in claim 12.

17. The hydroisomerization catalyst of claim 16, wherein, based on the total weight of the hydroisomerization catalyst of 100 wt%, the content (dry basis) of the composite molecular sieve is 1 wt%-80 wt% (preferably 10 wt%-70 wt%, more preferably 20 wt%-60 wt%), and the content (based on metal element) of the active metal component is 0.01 wt%-10 wt% (preferably 0.05 wt%-8.0 wt%, more preferably 0.1 wt%-5.0 wt%).

18. The hydroisomerization catalyst of claim 16, wherein the active metal component is selected from at least one noble metal element of Group VIII of the periodic table, preferably at least one of Pt and Pd, especially Pt.

19. A hydroisomerization method (e.g., a dewaxing method for lubricating oil fractions), comprising the step of hydroisomerizing n-alkanes (e.g., paraffinic hydrocarbons) in the presence of the hydroisomerization catalyst of claim 16.

20. The hydroisomerization method of claim 19, wherein the conditions for the hydroisomerization reaction include: The reaction temperature was 250℃-420℃, the reaction pressure was 1.0MPa-20MPa, and the volume hourly space velocity was 0.5h⁻¹. -1 -4.0h -1 The hydrogen-to-oil volume ratio is 500:1-1400:1.

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