ZSM-5 molecular sieve, its manufacturing method and use, hydrotreating catalyst, hydrodewaxing catalyst and use thereof

Abstract

The present invention provides a ZSM-5 molecular sieve, its preparation method and use, and a hydrotreating catalyst, a hydrodewaxing catalyst and its use. The ZSM-5 molecular sieve of the present invention has a total acid amount of 0.03-0.40 mmol / g as measured by infrared spectroscopy of pyridine, a total acid amount of 0.002-0.02 mmol / g as measured by infrared spectroscopy of di-tert-butylpyridine, a mesopore volume of 10%-20% of the total pore volume, and / or a mesopore volume of 2-10 nm of 70%-95% of the total mesopore volume. The molecular sieve has significant technical advantages as a carrier or active component, for example, when the hydrodewaxing catalyst produced by the ZSM-5 molecular sieve is used in the treatment of oil products, both the quality and yield of low-freezing point oil products can be improved.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of Chinese Patent Application No. 202111269100.0, filed on October 29, 2021, the contents of which are incorporated herein by reference.

[0002] [Technical Field] The present invention relates to the field of molecular sieves and their production, in particular to ZSM-5 molecular sieves, their production methods and uses, as well as hydrotreating catalysts, hydrodewaxing catalysts and their uses. [Background technology]

[0003] In 1972, Mobile succeeded in synthesizing the first molecular sieve belonging to the "Pentasil" family using tetraethylammonium hydroxide as a template agent, and named this molecular sieve ZSM-5. The emergence of this molecular sieve was a milestone in the development of molecular sieves. In 1978, Kokotailo et al. analyzed the structure of ZSM-5 molecular sieves and confirmed that they have a three-dimensional double 10-membered ring pore channel structure with linear and sinusoidal pore channels, respectively. The two types of 10-membered ring pore channels are orthogonal to each other. The linear 10-membered ring pore channels are parallel to the b axis and have a pore size of 0.53 × 0.56 nm. The sinusoidal 10-membered ring pore channels are parallel to the a axis and have a pore size of 0.51 × 0.55 nm. The cell parameters are a = 2.017 nm, b = 1.996 nm, and c = 1.343 nm, respectively. These pore structure features result in shape-selective catalytic properties. In hydrodewaxing reactions, most cyclic and isoparaffinic hydrocarbons have molecular dynamic sizes larger than those of the 10-membered ring pore channels of ZSM-5 molecular sieves, preventing them from entering the pore channels and reacting inside. This allows for the selective cracking of linear hydrocarbons, which have poor low-temperature fluidity. In ZSM-5 molecular sieve raw powder, the acidity of the pore openings and outer surface can cause side reactions, which can affect catalytic performance.

[0004] To obtain catalysts with higher para selectivity and reaction stability, ZSM-5 molecular sieves must be modified. Among these, silanization of molecular sieves is a frequently used and effective method for modifying the acidity of the external surface. Current silanization methods can be classified into (1) vacuum chemical vapor deposition, (2) flow chemical vapor deposition, (3) liquid-phase chemical impregnation, (4) reflux liquid-phase deposition, and (5) chemical reactive deposition. Although these methods differ in process, their main purpose is to support amorphous silica on the external surface of the molecular sieve by deposition, thereby removing the external acidic centers. However, conventional silanization methods require repeated periodic impregnation to achieve the goal of removing the external acidic center, which results in the waste of large amounts of ester silane and significantly reduces the efficiency of the reforming process. While the improved chemical reactive deposition method improves the reforming efficiency and utilization rate of ester silane, it requires specialized operations, making the process complicated and inevitably leading to clogging of the pore channels. Summary of the Invention [Problem to be solved by the invention]

[0005] To overcome the shortcomings of the prior art, the present invention provides a ZSM-5 molecular sieve, its preparation method and use, and a hydrotreating catalyst, a hydrodewaxing catalyst and their uses. The ZSM-5 molecular sieve can be widely used as a support or active component. For example, a catalyst prepared using the ZSM-5 molecular sieve as a support can be used in the hydrodewaxing process of partially mixing catalytic diesel and / or coked diesel with straight-run diesel to improve both the quality and yield of low-freezing point diesel. [Means for solving the problem]

[0006] A first aspect of the present invention provides a ZSM-5 molecular sieve having a total acid amount of 0.03 to 0.40 mmol / g when measured with pyridine by infrared ray, a total acid amount of 0.002 to 0.02 mmol / g when measured with di-tert-butylpyridine by infrared ray, a mesopore volume of 10% to 20% of the total pore volume, and / or a mesopore volume of 2 to 10 nm that accounts for 70% to 95% of the total mesopore volume.

[0007] A second aspect of the present invention is (1) hydrothermally treating a raw ZSM-5 molecular sieve; Step (2) of removing non-framework aluminum in the molecular sieve obtained in step (1); Step (3) of impregnating the material obtained in step (2) with a pore channel protection liquid; Step (4) of treating the material obtained in step (3) with an organic acid; Step (5) of mixing the material obtained in step (4) with an aluminum removal and silicon replenishment reagent to remove aluminum and replenish silicon; and (6) filtering, washing, drying and roasting the material obtained in step (5).

[0008] A third aspect of the present invention provides the use of the molecular sieve as a support and / or catalytically active component, preferably as a hydrogenation catalyst support.

[0009] A fourth aspect of the present invention provides a hydrotreating catalyst containing the ZSM-5 molecular sieve of the present invention and a hydrogenation active component.

[0010] A fifth aspect of the present invention provides a hydrodewaxing catalyst containing the ZSM-5 molecular sieve of the present invention, preferably the ZSM-5 molecular sieve and a Group VIII metal component, wherein the content of the ZSM-5 molecular sieve is 30% to 90% and the content of the Group VIII metal component, calculated as an oxide, is 5% to 40%, based on the weight of the catalyst.

[0011] A sixth aspect of the present invention provides the use of the hydrodewaxing catalyst of the present invention in the hydrodewaxing of an oil product, preferably wherein the oil product is a blend of straight-run diesel and catalytic diesel and / or coked diesel. [Effects of the Invention]

[0012] Compared with the prior art, the present invention has the following advantages: 1. The ZSM-5 molecular sieve of the present invention has a low total acid content as measured by infrared spectroscopy using di-tert-butylpyridine, removes mesopore acids and external acids, and has a suitable mesopore distribution. The ZSM-5 molecular sieve can be widely used as a support or active component. For example, a catalyst prepared using the ZSM-5 molecular sieve as a support can be used in the hydrodewaxing process of partially mixing catalytic diesel and / or coked diesel with straight-run diesel to improve both the quality and yield of low-freezing point diesel. 2. In the method for producing ZSM-5 molecular sieves of the present invention, a certain amount of mesopores is first obtained by hydrothermal treatment, and then non-framework aluminum is removed to smooth the pore channels. Then, the acid centers in the non-zigzag pore channels are selectively removed by pore channel protection. Most of the aluminum sites in the non-zigzag pore channels are replaced with non-acidic silicon atoms through the action of the aluminum-removing silicon supplement, and the molecular sieve structure is maintained intact. In a preferred embodiment of the present invention, molecular sieves have the advantage of superior performance because they can retain a small amount of acid centers on the outer surface and within the mesopores as needed. For example, when used in hydrodewaxing, small amounts of polycyclic aromatic hydrocarbons that tend to adsorb to the feedstock are hydrogenated and ring-opened at the weak acid sites within the mesopores and on the outer surface, thereby improving the quality of diesel. High-quality, low-freezing-point monocyclic hydrocarbons and isocyclic hydrocarbons have low competitive adsorption capacity and are difficult to enter the micropore channels of ZSM-5 molecular sieves, so they are retained in the product. Because the adsorption capacity of n-alkanes is weaker than that of aromatic hydrocarbons, they do not dominate competitive adsorption outside the pore channels, and therefore enter the micropore channels and undergo shape-selective cracking reactions, resulting in primary cracking products with lowered freezing points. The reduction in acid centers on the outer surface prevents the cracking products from continuing to crack into smaller non-diesel components. The smooth pore channels allow primary cracking products to diffuse out of the pore channels in a timely manner, reducing secondary cracking and ultimately significantly increasing the yield of low-freezing-point diesel. [Brief explanation of the drawings]

[0013] [Figure 1] 1 shows XRD patterns of a commercially available ZSM-5 molecular sieve, the ZSM-5 molecular sieve Z-T4 obtained in Example 4 of the present invention, and the molecular sieve ZB obtained in Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0014] The functions and effects of the technical solution of the present invention will be further illustrated below with reference to examples and comparative examples, but the following examples do not limit the protection scope of the present invention.

[0015] The present invention provides a ZSM-5 molecular sieve, wherein the total acid content of pyridine of the ZSM-5 molecular sieve as measured by infrared spectroscopy is 0.03 to 0.40 mmol / g, for example, 0.03 mmol / g, 0.04 mmol / g, 0.05 mmol / g, 0.06 mmol / g, 0.07 mmol / g, 0.08 mmol / g, 0.09 mmol / g, 0.10 mmol / g, 0.11 mmol / g, 0.12 mmol / g, 0.13 mmol / g, 0.14mmol / g, 0.15mmol / g, 0.16mmol / g, 0.17mmol / g, 0.18mmol / g, 0.19mmol / g, 0.20mmol / g, 0.21mmol / g, 0.22mm ol / g, 0.23mmol / g, 0.24mmol / g, 0.25mmol / g, 0.26mmol / g, 0.27mmol / g, 0.28mmol / g, 0.29mmol / g, 0.30mmol / g, 0. The total acid content of di-tert-butylpyridine measured by infrared measurement is 0.002 to 0.02 mmol / g, for example, 0.002 mmol / g, 0.003 mmol / g, 0.004 mmol / g, 0.31 mmol / g, 0.32 mmol / g, 0.33 mmol / g, 0.34 mmol / g, 0.35 mmol / g, 0.36 mmol / g, 0.37 mmol / g, 0.38 mmol / g, 0.39 mmol / g, 0.40 mmol / g. mmol / g, 0.005mmol / g, 0.006mmol / g, 0.007mmol / g, 0.008mmol / g, 0.009mmol / g, 0.010mmol / g, 0.011mmol / g, 0.0 12mmol / g, 0.013mmol / g, 0.014mmol / g, 0.015mmol / g, 0.016mmol / g, 0.017mmol / g, 0.018mmol / g, 0.019mmol / g, 0.020 mmol / g, the mesopore volume of the ZSM-5 molecular sieve accounts for 10% to 20%, for example, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%, of the total pore volume, and / or the volume of 2-10 nm mesopores in the ZSM-5 molecular sieve accounts for 70% to 95%, for example, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95% of the total mesopore volume.

[0016] According to a preferred embodiment of the present invention, the total acid amount of pyridine in the ZSM-5 molecular sieve measured by infrared spectroscopy is 0.10 to 0.20 mmol / g, for example, 0.10 mmol / g, 0.11 mmol / g, 0.12 mmol / g, 0.13 mmol / g, 0.14 mmol / g, 0.15 mmol / g, 0.16 mmol / g, 0.17 mmol / g, 0.18 mmol / g, 0.19 mmol / g, or 0.20 mmol / g, and the total acid amount of di-tert-butylpyridine measured by infrared spectroscopy is 0.005 to 0.01 mmol / g, for example, 0.005 mmol / g, 0.006 mmol / g, 0.007 mmol / g, 0.008 mmol / g, 0.009 mmol / g, or 0.010 mmol / g.

[0017] According to one preferred embodiment of the present invention, the ratio of the SiO2 / Al2O3 molar ratio of the outer surface of the ZSM-5 molecular sieve to the total SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 2-100:1, preferably 5-30:1, for example, 5:1, 6:1, 7:1, 8:1, 8:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 26:1, 27:1, 28:1, 29:1, 30:1.

[0018] According to a preferred embodiment of the present invention, the SiO2 / Al2O3 molar ratio on the outer surface of the ZSM-5 molecular sieve is 200-1000, preferably 500-1000.

[0019] According to a preferred embodiment of the present invention, the total SiO2 / Al2O3 molar ratio of said ZSM-5 molecular sieve is 30-100, preferably 40-70.

[0020] According to a preferred embodiment of the present invention, the mesopore volume of the ZSM-5 molecular sieve accounts for 10% to 20% of the total pore volume.

[0021] According to a preferred embodiment of the present invention, in the ZSM-5 molecular sieve, the volume of mesopores having a size of 2 to 10 nm accounts for 70% to 95% of the total mesopore volume.

[0022] The molecular sieve of the present invention having the above-mentioned characteristics can achieve the object of the present invention, and there is no particular requirement for its manufacturing method. According to one preferred embodiment of the present invention, the present invention is (1) hydrothermally treating a raw ZSM-5 molecular sieve; Step (2) of removing non-framework aluminum in the molecular sieve obtained in step (1); Step (3) of impregnating the material obtained in step (2) with a pore channel protection liquid; Step (4) of treating the material obtained in step (3) with an organic acid; Step (5) of mixing the material obtained in step (4) with an aluminum removal and silicon replenishment reagent to remove aluminum and replenish silicon; and (6) filtering, washing, drying and roasting the material obtained in step (5).

[0023] In the present invention, the ZSM-5 molecular sieve raw material may be a commercially available product or a macroporous hydrogen-type ZSM-5 molecular sieve manufactured by a conventional technique. Preferably, the ZSM-5 molecular sieve raw material has the following characteristics: an SiO2 / Al2O3 molar ratio of 30 to 100, a specific surface area of ​​300 to 450 m 2 / g, pore volume 0.15-0.20 cm 3 / g.

[0024] According to a preferred embodiment of the present invention, in step (1), the temperature of the hydrothermal treatment is 400 to 700°C, preferably 500 to 600°C.

[0025] According to the present invention, the time of the hydrothermal treatment is adjusted depending on the temperature, and in the present invention, the time of the hydrothermal treatment is preferably 0.5 to 5 hours, and more preferably 1 to 2 hours.

[0026] According to the present invention, the pressure of the hydrothermal treatment is adjusted depending on the temperature, and in the present invention, the pressure of the hydrothermal treatment is 0.05 to 0.5 MPa, preferably 0.1 to 0.3 MPa.

[0027] In the present invention, there are several methods for removing non-framework aluminum, including, but not limited to, removing non-framework aluminum using a buffer solution. The buffer solution refers to a mixed solution consisting of a weak acid and its salt, or a weak base and its corresponding salt, which can to some extent eliminate or reduce the effect of an externally added strong acid or strong base on the acidity / alkalinity of the solution, thereby maintaining the pH value of the solution relatively stable.

[0028] In the present invention, unless otherwise specified, the solution refers to an aqueous solution.

[0029] In the present invention, the weak acid is preferably an inorganic acid and / or an organic acid having a molecular size of less than 0.5 nm and capable of being removed without damaging the structure of the molecular sieve by roasting or the like.

[0030] According to one preferred embodiment of the invention, the inorganic acid is one or more of phosphoric acid, carbonic acid, and boric acid.

[0031] According to one preferred embodiment of the present invention, the inorganic acid salts are ammonium salts of phosphoric acid, carbonic acid and boric acid.

[0032] According to one preferred embodiment of the present invention, the organic acid is selected from C2 to C6 monobasic or polybasic acids, preferably one or more of citric acid, formic acid, acetic acid, oxalic acid, propionic acid, malonic acid, butyric acid, and succinic acid.

[0033] According to one preferred embodiment of the present invention, the organic acid salt is selected from C2 to C6 monobasic or polybasic acid salts, preferably one or more of ammonium salts of citric acid, formic acid, acetic acid, oxalic acid, propionic acid, malonic acid, butyric acid, and succinic acid.

[0034] According to one preferred embodiment of the present invention, more preferably, the buffer solution is one or more of an oxalic acid-ammonium oxalate solution and an acetic acid-ammonium acetate solution.

[0035] According to one preferred embodiment of the present invention, the buffer solution is acidic, and preferably has a pH value in the range of 4.5 to 6.5.

[0036] According to one preferred embodiment of the present invention, the molar concentration of the organic acid in the buffer solution is 0.1 to 1.0 mol / L.

[0037] In the present invention, the amount of the buffer solution used can be in a wide range. According to one preferred embodiment of the present invention, the liquid / solid volume ratio of the buffer solution to the molecular sieve obtained in step (1) is 3:1 to 10:1.

[0038] According to a preferred embodiment of the present invention, the process of step (2) includes mixing and stirring the molecular sieve obtained in step (1) with a buffer solution, followed by solid-liquid separation, and optionally repeating the above procedure 2 to 4 times. According to the present invention, the treatment temperature is preferably 40 to 80°C, and the treatment time is adjusted according to the temperature, but is preferably 0.5 to 3 hours.

[0039] In the present invention, the pore channel protecting agent of the pore channel protecting solution is one or more of inorganic alkalis or organic alkalis having a molecular size of less than 0.5 nm and easily removable by means such as roasting without damaging the structure of the molecular sieve, such as ammonia water, ethylenediamine, propylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetramethylammonium bromide, and tetraethylammonium bromide.

[0040] According to one preferred embodiment of the present invention, in step (3), the pore channel protecting agent of the pore channel protecting solution is one or more of isopropylamine solution, tetramethylammonium hydroxide, tetraethylammonium hydroxide solution, and tetrapropylammonium hydroxide.

[0041] According to one preferred embodiment of the present invention, the pore channel protection liquid is preferably an aqueous solution of a pore channel protection agent, preferably one or more of an isopropylamine solution, a tetraethylammonium hydroxide solution, and a tetrapropylammonium hydroxide solution.

[0042] According to one preferred embodiment of the present invention, the concentration of the pore channel protecting solution is preferably 0.8 to 2.0 mol / L.

[0043] In the present invention, there is no particular requirement for the impregnation method, and in the present invention, the impregnation is preferably equal volume impregnation.

[0044] According to a preferred embodiment of the present invention, the temperature for the impregnation treatment is 20 to 25°C.

[0045] In the present invention, in step (4), the organic acid is preferably an organic acid having a molecular size of 0.55 nm to 2 nm and being easily removable by a method such as roasting that does not damage the structure of the molecular sieve, such as one or more C7 to C10 organic acids.

[0046] According to a preferred embodiment of the present invention, the organic acid is one or more of 2-methylbenzoic acid, 2-methylbenzenesulfonic acid, 2,4-xylenesulfonic acid, 2,4-dimethylbenzoic acid, 1,2,5-trimethylbenzenesulfonic acid, and 1,2,5-trimethylbenzoic acid.

[0047] According to a preferred embodiment of the present invention, in step (4), the organic acid is more preferably one or more of 2,4-xylenesulfonic acid and 2,4-dimethylbenzoic acid.

[0048] According to a preferred embodiment of the present invention, the treatment process in step (4) preferably includes firstly mixing the material obtained in step (3) with water, preferably in a liquid / solid volume ratio of 2:1 to 6:1 between the water and the material obtained in step (3); and then adding an organic acid until the pH value of the solution is reduced to below 8, preferably 6.5 to 7.5.

[0049] In the present invention, in step (5), the aluminum-removing silicon replenisher can be of a wide variety of types. According to a preferred embodiment of the present invention, the aluminum-removing silicon replenisher of the aluminum-removing silicon replenisher reagent is one or more of fluorosilicic acid, fluorosilicic acid salts (including but not limited to ammonium hexafluorosilicate, fluorosilicic acid, and sodium fluorosilicate), silicon halides (including but not limited to silicon tetrachloride and silicon tetrafluoride), and silicates (including but not limited to ethyl orthosilicate), preferably one or more of ammonium hexafluorosilicate, fluorosilicic acid, sodium fluorosilicate, silicon tetrachloride, silicon tetrafluoride, and ethyl orthosilicate, more preferably, the aluminum-removing silicon replenisher reagent is at least one of ammonium hexafluorosilicate solution and ethyl orthosilicate solution.

[0050] According to a preferred embodiment of the present invention, the molar concentration of the aluminum-removing silicon-replenishing reagent is 0.3 to 1.0 mol / L.

[0051] In the present invention, the range of the amount of aluminum-removing silicon replenisher reagent used is wide, and according to a preferred embodiment of the present invention, the mass ratio of the material obtained in step (4) to the aluminum-removing silicon replenisher reagent is 1:1 to 1:5.

[0052] According to a preferred embodiment of the present invention, in step (5), the mixing temperature is 60 to 100°C.

[0053] According to a preferred embodiment of the present invention, the operation process of step (5) includes heating the material obtained in step (4) to 60-100°C, continuously stirring, adding aluminum-removing silicon-replenishing reagent dropwise, and continuing stirring for 60-120 minutes after the dropwise addition is completed.

[0054] According to one preferred embodiment of the present invention, in step (6), the filtration and washing may be performed by a method commonly used in the art, the drying temperature is 100°C to 150°C, the drying time is 2 to 4 hours, the roasting temperature is 400°C to 600°C, and the roasting time is 3 to 5 hours.

[0055] According to the present invention, there is provided the use of the molecular sieve of the present invention as a support and / or catalytically active component, preferably as a hydrogenation catalyst support.

[0056] According to the present invention, there is provided a hydrotreating catalyst comprising the ZSM-5 molecular sieve of the present invention and a hydrogenation active component, wherein the hydrogenation active component is preferably one or more selected from Group VIB, VIIB and VIII metals, preferably one or more selected from Pt, Pd, Ni, W, Mo and Co.

[0057] According to the present invention, there is provided a hydrodewaxing catalyst containing the ZSM-5 molecular sieve of the present invention.

[0058] According to a preferred embodiment of the present invention, the hydrodewaxing catalyst preferably comprises the ZSM-5 molecular sieve and a Group VIII metal component, and the content of the ZSM-5 molecular sieve is 30% to 90% based on the weight of the catalyst, and the content of the Group VIII metal component, calculated as an oxide, is 5% to 40% based on the weight of the catalyst.

[0059] The present invention provides a use of the hydrodewaxing catalyst of the present invention in the hydrodewaxing of an oil product, wherein the oil product is preferably a blend of straight-run diesel and catalytic diesel and / or coked diesel.

[0060] According to a preferred embodiment of the present invention, the SiO2 / Al2O3 molar ratio on the outer surface of the ZSM-5 molecular sieve is 200-1000, the total SiO2 / Al2O3 molar ratio is 30-100, the total acid amount of pyridine measured by infrared spectroscopy is 0.03-0.40 mmol / g, and the total acid amount of di-tert-butylpyridine measured by infrared spectroscopy is 0.002-0.02 mmol / g, and the mesopore volume of the ZSM-5 molecular sieve accounts for 10%-20% of the total pore volume.

[0061] According to a preferred embodiment of the present invention, preferably, the SiO2 / Al2O3 molar ratio of the outer surface of the ZSM-5 molecular sieve is 500-1000, and the total SiO2 / Al2O3 molar ratio is 40-70.

[0062] According to a preferred embodiment of the present invention, the total acid amount of pyridine of the ZSM-5 molecular sieve measured by infrared ray is preferably 0.10 to 0.20 mmol / g, and the total acid amount of di-tert-butylpyridine measured by infrared ray is preferably 0.005 to 0.01 mmol / g.

[0063] According to a preferred embodiment of the present invention, the mesopores in the ZSM-5 molecular sieve are preferably concentrated in the range of 2 to 10 nm, and the volume of mesopores in the range of 2 to 10 nm accounts for 70% to 95% of the total mesopore volume. In the present invention, mesopores are pores with a pore diameter of 2 to 50 nm.

[0064] According to one preferred embodiment of the present invention, the present invention comprises: (1) hydrothermally treating a ZSM-5 molecular sieve; Step (2) of removing non-framework aluminum in the molecular sieve obtained in step (1); Step (3) of impregnating the material obtained in step (2) with a pore channel protection liquid; Step (4) of treating the material obtained in step (3) with an organic acid; Step (5) of mixing the material obtained in step (4) with an aluminum removal and silicon replenishment reagent to remove aluminum and replenish silicon; and (6) filtering, washing, drying, and roasting the material obtained in step (5) to obtain a ZSM-5 molecular sieve.

[0065] According to one preferred embodiment of the present invention, preferably, in step (1), the temperature of the hydrothermal treatment is 400 to 700°C, preferably 500 to 600°C, the time is 0.5 to 5 hours, preferably 1 to 2 hours, and the pressure is 0.05 to 0.5 MPa, preferably 0.1 to 0.3 MPa.

[0066] According to one preferred embodiment of the present invention, the method for removing non-framework aluminum in step (2) may preferably be a method for removing non-framework aluminum using a buffer solution. The buffer solution used is one or more of an oxalic acid-ammonium oxalate solution and an acetic acid-ammonium acetate solution. The pH value of the buffer solution ranges from 4.5 to 6.5, preferably from 5.0 to 6.0. The molar concentration of the organic acid in the buffer solution is 0.1 to 1.0 mol / L. The liquid / solid volume ratio of the buffer solution to the molecular sieve obtained in step (1) is 3:1 to 10:1.

[0067] According to one preferred embodiment of the present invention, the specific treatment process in step (2) is preferably as follows: the molecular sieve obtained in step (1) is mixed with a buffer solution and stirred, the treatment temperature is 40 to 80°C, the treatment time is 0.5 to 3 hours, and then solid-liquid separation (for example, suction filtration) is performed, and the above operation is repeated 2 to 4 times.

[0068] According to a preferred embodiment of the present invention, in step (3), the pore channel protection solution is preferably one or more of an isopropylamine solution, a tetraethylammonium hydroxide solution, a tetrapropylammonium hydroxide solution, etc. The concentration of the pore channel protection solution is 0.8 to 2.0 mol / L, preferably 1.1 to 1.5 mol / L.

[0069] According to one preferred embodiment of the present invention, in step (3), the impregnation is preferably equal volume impregnation. The temperature of the impregnation treatment is room temperature, generally 20 to 25°C.

[0070] According to one preferred embodiment of the present invention, in step (4), the organic acid is preferably one or more of 2,4-xylenesulfonic acid and 2,5-dimethylbenzoic acid.

[0071] According to one preferred embodiment of the present invention, the specific operation is preferably as follows: First, the material obtained in step (3) is mixed with water so that the liquid / solid volume ratio of the water to the material obtained in step (3) is 2:1 to 6:1, and then an organic acid is added until the pH value of the solution is reduced to 8 or less, preferably 6.5 to 7.5.

[0072] According to one preferred embodiment of the present invention, in step (5), the aluminum-removing silicon replenisher reagent is preferably at least one of an ammonium hexafluorosilicate solution, an ethyl orthosilicate solution, etc. The molar concentration of the aluminum-removing silicon replenisher reagent is 0.3 to 1.0 mol / L. The mass ratio of the material obtained in step (4) to the aluminum-removing silicon replenisher reagent is 1:1 to 1:5. The mixing temperature is 60 to 100°C.

[0073] According to a preferred embodiment of the present invention, the specific operation procedure of step (5) is as follows: the material obtained in step (4) is rapidly heated to 60-100°C and continuously stirred, and the aluminum removal and silicon replenishment reagent is added dropwise. After the addition is completed, stirring is continued for 60-120 minutes. The addition rate is 0.5 mL / min g or less (material obtained in step (4)), preferably 0.2-0.4 mL / min g or less (material obtained in step (4)).

[0074] According to one preferred embodiment of the present invention, in step (6), the filtration and washing may be performed by a method commonly used in the art, the drying temperature is 100°C to 150°C, the drying time is 2 to 4 hours, the roasting temperature is 400°C to 600°C, and the roasting time is 3 to 5 hours.

[0075] According to one preferred embodiment of the present invention, there is provided a hydrodewaxing catalyst comprising the above-described ZSM-5 molecular sieve.

[0076] According to one preferred embodiment of the present invention, the hydrodewaxing catalyst preferably comprises the ZSM-5 molecular sieve and a Group VIII metal component, and the content of the ZSM-5 molecular sieve is 30% to 90%, preferably 40% to 70%, based on the weight of the catalyst, and the content of the Group VIII metal component, calculated as an oxide, is 5% to 40%, preferably 10% to 30%.

[0077] According to one preferred embodiment of the present invention, the hydrodewaxing catalyst preferably comprises the ZSM-5 molecular sieve, alumina, and a Group VIII metal component, and the content of the ZSM-5 molecular sieve is 30% to 50%, the content of alumina is 40% to 70%, and the content of the Group VIII metal component, calculated as an oxide, is 5% to 40%, based on the weight of the catalyst.

[0078] According to one preferred embodiment of the present invention, preferably said Group VIII metal is cobalt and / or nickel.

[0079] According to one preferred embodiment of the present invention, the present invention provides the use of the above-described hydrodewaxing catalyst in the hydrodewaxing of a feedstock.

[0080] According to one preferred embodiment of the present invention, the use preferably comprises reacting a feedstock with the action of the above-mentioned hydrodewaxing catalyst in the presence of hydrogen to obtain a low-freezing point diesel.

[0081] According to one preferred embodiment of the present invention, the reaction conditions for hydrodewaxing in the above-mentioned use are preferably a reaction pressure of 5.0 to 8.0 MPa, a hydrogen / oil volume ratio of 400:1 to 600:1, and a liquid hourly space velocity of 0.5 to 2 h -1 The reaction temperature is 280 to 400°C.

[0082] According to one preferred embodiment of the present invention, the feedstock is preferably a blend of straight-run diesel and catalytic diesel and / or coked diesel. In the feedstock, the total blend amount of catalytic diesel and / or coked diesel is 20% to 40%, the wax (n-alkane with more than 20 carbon atoms) content is 5% to 15% by mass, and the polycyclic aromatic hydrocarbon content is 10% to 30% by mass. The distillation range of the feedstock is typically 150 to 400°C. [Example]

[0083] In the present invention, % in the examples and comparative examples means mass fraction unless otherwise specified.

[0084] In this invention, the SiO2 / Al2O3 molar ratio on the outer surface is measured by X-ray photoelectron spectroscopy (XPS), and the elemental composition and state of the catalyst surface are measured by a Multilab2000 electron energy spectrometer (Thermo Fisher Scientific, USA), with an excitation source of MgKα and a cathode voltage and current of 13 kV and 20 mA, respectively. The electron binding energy is calibrated using C1s (284.6 eV).

[0085] In the present invention, the total SiO2 / Al2O3 molar ratio is obtained by X-ray fluorescence spectroscopy (XRF) analysis, using a ZSX100e X-ray fluorescence spectrometer, the spectral line is Kα, the crystal is LiF1, the target material is Rh, the detector is an SC scintillation counter, the timing is 20 seconds, and the atmosphere of the optical path is vacuum.

[0086] In the present invention, the specific surface area, pore volume, and pore distribution are measured as follows: A low-temperature liquid nitrogen physical adsorption apparatus ASAP 2420 manufactured by Micromeritics, Inc., USA, is used, and the pretreatment temperature is 300°C and the pretreatment time is 4 hours.

[0087] In the present invention, the infrared measurement method for pyridine is as follows: Powdered ZSM-5 molecular sieve is pressed into a sheet, vacuum-suctioned, and degassed at 450°C for 2 hours. After the temperature is lowered to room temperature, the infrared spectrum of chemical desorption is measured using pyridine molecules as probe molecules, and the amount of adsorption is calculated.

[0088] In the present invention, the total acid amount of di-tert-butylpyridine measured by infrared spectroscopy refers to the protonic acid that can be contacted by a 2,6-di-tert-butylpyridine molecule with a dynamic diameter of 10.5 Å. The infrared spectroscopy method for 2,6-di-tert-butylpyridine is as follows: Powdered ZSM-5 molecular sieve is pressed into a sheet, vacuumed, and degassed at 450°C for 2 hours. After the temperature is lowered to room temperature, the infrared spectrum of chemical desorption is measured using 2,6-di-tert-butylpyridine molecules as probe molecules, and the adsorption amount is calculated.

[0089] The ZSM-5 raw material powder according to the examples and comparative examples of the present invention is a commercially available product, which is a microporous hydrogen-type ZSM-5 molecular sieve. The characteristics of the ZSM-5 are a specific surface area of ​​405 m 2 / g, pore volume 0.182 cm 3 / g, water absorption is 55%, and SiO2 / Al2O3 ratio (molar) is 31.2.

[0090] Example 1 30 g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 500 °C and 0.1 MPa for 2 h. The resulting material was added to 300 mL of oxalic acid-ammonium oxalate solution with a pH of 6.0 and an oxalic acid molar concentration of 0.3 mol / L. The mixture was stirred and heated to 60 °C for 30 min, then suction filtered. This process was repeated three times. Then, 16.5 mL of 1.1 mol / L isopropylamine solution was added in equal volumes and allowed to stand for 10 min. 170 mL of water was added, and 2,5-xylenesulfonic acid was added dropwise until the pH reached 6.5. The mixture was then heated to 60 °C with stirring. 90 mL of 0.3 mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.2 mL / min g using a peristaltic pump. The temperature was maintained at 60 °C and the mixture was stirred for 90 min. The mixture was filtered under suction while still hot, and 300 mL of water was added to the filter cake. The mixture was heated to 60°C and kept at that temperature for 20 minutes. The mixture was then filtered under suction while still hot, and the filter cake was dried at 120°C for 24 hours, and then roasted at 500°C for 3 hours to obtain a molecular sieve, which was named Z-T1.

[0091] Example 2 30 g of commercially available ZSM-5 powder was placed in a hydrothermal treatment furnace and treated at 530 °C and 0.1 MPa for 2 h. The resulting material was added to 300 mL of acetic acid-ammonium acetate solution with a pH of 6.0 and a molar concentration of 0.2 mol / L acetic acid, stirred, and heated to 60 °C for 30 min. This process was repeated three times. Subsequently, 16.5 mL of 1.2 mol / L tetraethylammonium hydroxide solution was added in equal volumes. After 10 min of standing, 170 mL of water was added, and 2,5-dimethylbenzoic acid was added dropwise until the pH reached 7.0. The mixture was heated to 65 °C with stirring. 90 mL of 0.5 mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.2 mL / min g using a peristaltic pump. The temperature was maintained at 65 °C and stirring was continued for 90 min. The mixture was filtered under suction while still hot, and 300 mL of water was added to the filter cake. The mixture was heated to 60°C and kept at this temperature for 20 minutes. The mixture was then filtered under suction while still hot, and the filter cake was dried at 120°C for 24 hours, and then roasted at 500°C for 3 hours to obtain a molecular sieve, which was named Z-T2.

[0092] Example 3 30 g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 550 °C and 0.1 MPa for 2 h. The resulting material was added to 300 mL of 0.4 mol / L oxalic acid-ammonium oxalate solution with a pH of 5.5 and an oxalic acid molar concentration of 0.4 mol / L. The mixture was stirred and heated to 70 °C for 30 min, then suction filtered. This process was repeated three times. The resulting material was impregnated with 16.5 mL of 1.2 mol / L tetrapropylammonium hydroxide solution in equal volumes. After 10 min of standing, 170 mL of water was added, and 2,4-xylenesulfonic acid was added dropwise until the pH reached 6.5. The mixture was heated to 65 °C with stirring. 90 mL of 0.6 mol / L ethyl orthosilicate solution was added dropwise at a rate of 0.3 mL / min g using a peristaltic pump. The temperature was maintained at 65 °C and the mixture was stirred for 90 min. The mixture was filtered under suction while still hot, and 300 mL of water was added to the filter cake. The mixture was heated to 60°C and kept at this temperature for 20 minutes. The mixture was then filtered under suction while still hot. The filter cake was dried at 120°C for 24 hours and then roasted at 500°C for 3 hours to obtain a molecular sieve, which was named Z-T3.

[0093] Example 4 30 g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 550 °C and 0.15 MPa for 2 h. The resulting material was then added to 300 mL of a 0.4 mol / L oxalic acid-ammonium oxalate solution with a pH of 5.5 and stirred at 80 °C for 30 min. The mixture was then vacuum filtered. This process was repeated three times. The resulting material was then impregnated with 16.5 mL of a 1.2 mol / L isopropylamine solution at an equal volume. After 10 min of standing, 170 mL of water was added. 2,4-xylenesulfonic acid was added dropwise until the pH reached 7.0. The mixture was then heated to 65 °C with stirring. 90 g of a 0.6 mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.3 mL / min g using a peristaltic pump. The temperature was maintained at 65 °C and the mixture was stirred for 90 min. The mixture was filtered under suction while still hot, and 300 mL of water was added to the filter cake. The mixture was heated to 60°C and kept at this temperature for 20 minutes. The mixture was then filtered under suction while still hot. The filter cake was dried at 120°C for 24 hours and then roasted at 500°C for 3 hours to obtain a molecular sieve, which was named Z-T4.

[0094] Example 5 30 g of commercial ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 550 °C and 0.15 MPa for 2 h. The resulting material was added to 300 mL of 0.3 mol / L oxalic acid-ammonium oxalate solution with a pH of 5.0 and oxalic acid concentration. The mixture was stirred and heated to 60 °C and suction filtered for 30 min. This process was repeated three times. The resulting material was impregnated with 16.5 mL of 1.2 mol / L isopropylamine solution at an equal volume. After 10 min of standing, 170 mL of water was added, and 2,4-dimethylbenzoic acid was added dropwise until the pH reached 7.0. The mixture was heated to 65 °C with stirring. 90 mL of 0.6 mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.3 mL / min g using a peristaltic pump. The temperature was maintained at 65 °C and the mixture was stirred for 90 min. The mixture was filtered under suction while still hot, and 300 mL of water was added to the filter cake. The mixture was heated to 60°C and kept at this temperature for 20 minutes. The mixture was then filtered under suction while still hot, and the filter cake was dried at 120°C for 24 hours, and then roasted at 500°C for 3 hours to obtain a molecular sieve, which was named Z-T5.

[0095] Example 6 30 g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 550 °C and 0.15 MPa for 2 h. The resulting material was then added to 300 mL of acetic acid-ammonium acetate solution (pH 5.0, 0.3 mol / L acetic acid), stirred, heated to 60 °C, and suction filtered for 30 min. This process was repeated three times. The resulting material was then impregnated with an equal volume of 16.5 mL of 1.3 mol / L tetraethylammonium hydroxide solution, allowed to stand for 10 min, added with 170 mL of water, and 2,4-xylenesulfonic acid was added dropwise until the pH reached 7.5. The mixture was then heated to 65 °C with stirring. 90 mL of 0.6 mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.3 mL / min g using a peristaltic pump. The temperature was maintained at 65 °C and the mixture was stirred for 90 min. The mixture was filtered under suction while still hot, and 300 mL of water was added to the filter cake. The mixture was heated to 60°C and kept at this temperature for 20 minutes. The mixture was then filtered under suction while still hot, and the filter cake was dried at 120°C for 24 hours, and then roasted at 500°C for 3 hours to obtain a molecular sieve, which was named Z-T6.

[0096] Example 7 Thirty grams of commercially available ZSM-5 powder was placed in a hydrothermal furnace and treated at 570 °C and 0.15 MPa for 2 hours. The resulting material was then added to 300 mL of a 0.5 mol / L acetic acid-ammonium acetate solution with a pH of 5.0 and stirred at 60 °C for 30 minutes. This process was repeated three times. The resulting material was then impregnated with 16.5 mL of a 1.5 mol / L isopropylamine solution at an equal volume. After 10 minutes of settling, 170 mL of water was added, and 2,4-dimethylbenzoic acid was added dropwise until the pH reached 7.5. The mixture was then heated to 65 °C with stirring. 90 mL of a 0.8 mol / L ethyl orthosilicate solution was added dropwise at a rate of 0.4 mL / min g using a peristaltic pump. The temperature was maintained at 65 °C and the mixture was stirred for 90 minutes. The mixture was filtered under suction while still hot, and 300 mL of water was added to the filter cake. The mixture was heated to 60°C and kept at this temperature for 20 minutes. The mixture was then filtered under suction while still hot, and the filter cake was dried at 120°C for 24 hours, and then roasted at 500°C for 3 hours to obtain a molecular sieve, which was named Z-T7.

[0097] Example 8 30 g of commercial ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 570 °C and 0.2 MPa for 2 h. The resulting material was then added to 300 mL of a 0.5 mol / L oxalic acid-ammonium oxalate solution with a pH of 5.0 and stirred at 60 °C for 30 min. The mixture was then vacuum filtered. This process was repeated three times. The resulting material was then impregnated with 16.5 mL of a 1.5 mol / L isopropylamine solution at an equal volume. After 10 min of standing, 170 mL of water was added, and 2,4-dimethylbenzoic acid was added dropwise until the pH reached 7.5. The mixture was then heated to 65 °C with stirring. 90 mL of a 1.0 mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.4 mL / min g using a peristaltic pump. The temperature was maintained at 65 °C and the mixture was stirred for 90 min. The mixture was filtered under suction while still hot, and 300 mL of water was added to the filter cake. The mixture was heated to 60°C and kept at this temperature for 20 minutes. The mixture was then filtered under suction while still hot, and the filter cake was dried at 120°C for 24 hours, and then roasted at 500°C for 3 hours to obtain a molecular sieve, which was named Z-T8.

[0098] Comparative Example 1 Thirty grams of commercially available ZSM-5 raw powder was placed in a hydrothermal furnace and treated at 550°C and 0.15 MPa for 2 hours. The resulting material was added to 300 mL of an oxalic acid-ammonium oxalate solution with a pH of 5.0 and an oxalic acid molar concentration of 0.3 mol / L, stirred, heated to 60°C, and suction filtered for 30 minutes. This process was repeated three times. The filter cake was dried at 120°C for 24 hours and then roasted at 500°C for 3 hours to obtain a molecular sieve, designated ZB.

[0099] Comparative Example 2 30 g of commercially available ZSM-5 raw powder was placed in a hydrothermal furnace and treated at 550 °C and 0.15 MPa for 2 hours. The resulting material was added to 300 mL of 0.3 mol / L oxalic acid-ammonium oxalate solution with a pH of 5.0 and an oxalic acid concentration of 0.3 mol / L. The mixture was stirred and heated to 60 °C, then suction filtered for 30 minutes. This process was repeated three times. 90 mL of 0.6 mol / L ammonium hexafluorosilicate solution was added dropwise using a peristaltic pump at a rate of 0.3 mL / min g. The mixture was maintained at 65 °C and stirred for 90 minutes. The mixture was then suction filtered while hot. The filter cake was dried at 120 °C for 24 hours and then roasted at 500 °C for 3 hours to obtain a molecular sieve, designated ZC.

[0100] Comparative Example 3 Thirty grams of commercially available ZSM-5 powder was placed in a hydrothermal treatment furnace and treated at 550°C and 0.15 MPa for 2 hours. The resulting material was impregnated with 16.5 mL of 0.6 mol / L isopropylamine solution at an equal volume. The mixture was left to stand for 10 minutes, and then 170 mL of water was added. 2,4-dimethylbenzoic acid was added dropwise until the pH reached 7.0. The mixture was stirred and heated to 65°C. 90 mL of 0.6 mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.3 mL / min g using a peristaltic pump. The mixture was then stirred for 90 minutes while maintaining the temperature at 65°C. The mixture was filtered under suction while still hot, and 300 mL of water was added to the filter cake. The mixture was heated to 60°C and kept at that temperature for 20 minutes. The mixture was then filtered under suction while still hot, and the filter cake was dried at 120°C for 24 hours, and then roasted at 500°C for 3 hours to obtain a molecular sieve, which was named ZD.

[0101] Comparative Example 4 30 g of commercially available ZSM-5 raw powder was heated to 65°C with stirring, and 180 mL of 1.0 mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.4 mL / min g using a peristaltic pump. The temperature was maintained at 65°C and stirring was continued for 90 min. The mixture was then suction filtered while still hot. The filter cake was dried at 120°C for 24 h and then roasted at 500°C for 3 h to obtain a molecular sieve, designated ZE.

[0102] [Table 1]

[0103] Example 9 The buffer solution used was a citric acid-ammonium citrate solution with a pH value of 5.0, but was the same as in Example 5. The resulting molecular sieve was named Z-T9.

[0104] Example 10 The pore channel protection solution was 1.2 mol / L of ammonia water, except that the method was the same as in Example 5. The obtained molecular sieve was named Z-T10.

[0105] Example 11 The procedure was the same as in Example 5, except that the organic acid in step (4) was 2-methylbenzenesulfonic acid. The resulting molecular sieve was named Z-T11.

[0106] Example 12 The aluminum-removing silicon-replenishing reagent was 0.6 mol / L fluorosilicic acid solution, except that the procedure was the same as in Example 5. The resulting molecular sieve was named Z-T12.

[0107] Example 13 Catalysts were produced using the molecular sieves Z-T1 to Z-T12 obtained in Examples 1 to 12, respectively. In the production, the roasted molecular sieves and macroporous alumina (specific surface area: 302 m) were mixed. 2 / g, pore volume is 0.96 cm 3The catalysts were named C1 to C12, respectively. The mass fraction of the molecular sieve was 30 wt%, the mass fraction of the macroporous alumina was 50 wt%, the mass fraction of NiO was 10 wt%, and the remainder was the binder. 10 g of each of catalysts C1 to C12 was placed in a fixed-bed reactor, and the reaction pressure was 6.0 MPa, the hydrogen / oil volume ratio was 500:1, and the liquid hourly space velocity was 10 h -1 The hydrodewaxing reaction was carried out at a reaction temperature of 320° C. The characteristics of the raw material are shown in Table 2, and the product distribution and characteristics of the product are shown in Table 3.

[0108] [Table 2]

[0109] [Table 3]

[0110] Comparative Example 4 Commercially available ZSM-5 molecular sieves and macroporous alumina (specific surface area 302 m) 2 / g, pore volume is 0.96 cm 3 The catalyst DC1 was obtained by kneading ZSM-5 (ZSM-5 0.01g / g) with aluminum sol as a binder, extruding it into a strand shape, molding it, and then drying and roasting it. The carrier was then impregnated with an impregnation solution of nickel nitrate, followed by drying and roasting. The mass percentage of ZSM-5 was 30 wt%, the mass percentage of macroporous alumina was 50 wt%, the mass percentage of NiO was 10 wt%, and the remainder was the binder. 10 g of catalyst DC1 was placed in a fixed-bed reactor, and the reaction pressure was 6.0 MPa, the hydrogen / oil volume ratio was 500:1, and the liquid hourly space velocity was 10 h -1 The hydrodewaxing reaction was carried out under hydrodewaxing conditions of 1000 kJ / min, 1000 kJ / min, and a reaction temperature of 340° C. The characteristics of the raw materials are shown in Table 2, and the product distribution and characteristics of the products are shown in Table 4.

[0111] [Table 4]

[0112] Comparative Example 5 Molecular sieve ZB and macroporous alumina (specific surface area 302 m 2 / g, pore volume is 0.96 cm 3 The catalyst DC2 was obtained by kneading ZSM-5 (ZSM-5 0.01g / g) with aluminum sol as a binder, extruding it into a strand shape, molding it, and then drying and roasting it. The carrier was then impregnated with a nickel nitrate impregnation solution, followed by drying and roasting. The mass percentage of ZSM-5 was 30 wt%, the mass percentage of macroporous alumina was 50 wt%, the mass percentage of NiO was 10 wt%, and the remainder was the binder. 10 g of catalyst DC2 was placed in a fixed-bed reactor, and the reaction pressure was 6.0 MPa, the hydrogen / oil volume ratio was 500:1, and the liquid hourly space velocity was 10 h -1 The hydrodewaxing reaction was carried out under hydrodewaxing conditions of 1000 kJ / min, 1000 kJ / min, and a reaction temperature of 340° C. The characteristics of the raw materials are shown in Table 2, and the product distribution and characteristics of the products are shown in Table 5.

[0113] [Table 5]

[0114] Comparative Example 6 Molecular sieve ZC and macroporous alumina (specific surface area 302 m 2 / g, pore volume is 0.96 cm 3 The catalyst DC3 was obtained by kneading ZSM-5 (ZSM-5 0.01g / g) with aluminum sol as a binder, extruding it into a strand shape, molding it, and then drying and roasting it. The carrier was then impregnated with an impregnation solution of nickel nitrate, followed by drying and roasting. The mass percentage of ZSM-5 was 30 wt%, the mass percentage of macroporous alumina was 50 wt%, the mass percentage of NiO was 10 wt%, and the remainder was the binder. 10 g of catalyst DC3 was placed in a fixed-bed reactor, and the reaction pressure was 6.0 MPa, the hydrogen / oil volume ratio was 500:1, and the liquid hourly space velocity was 10 h -1 The hydrodewaxing reaction was carried out under hydrodewaxing conditions of 1000 kJ / min, 1000 kJ / min, and a reaction temperature of 340° C. The characteristics of the raw materials are shown in Table 2, and the product distribution and characteristics of the products are shown in Table 6.

[0115] [Table 6]

[0116] Comparative Example 7 Molecular sieve ZD and macroporous alumina (specific surface area 302 m 2 / g, pore volume is 0.96 cm 3 The catalyst DC4 was obtained by kneading ZSM-5 (ZSM-5 0.01g / g) with aluminum sol as a binder, extruding it into a strand shape, molding it, and then drying and roasting it. The carrier was then impregnated with a nickel nitrate impregnation solution, followed by drying and roasting. The mass percentage of ZSM-5 was 30 wt%, the mass percentage of macroporous alumina was 50 wt%, the mass percentage of NiO was 10 wt%, and the remainder was the binder. 10 g of catalyst DC4 was placed in a fixed-bed reactor, and the reaction pressure was 6.0 MPa, the hydrogen / oil volume ratio was 500:1, and the liquid hourly space velocity was 10 h -1 The hydrodewaxing reaction was carried out under hydrodewaxing conditions of 1000 kJ / min, 1000 kJ / min, and a reaction temperature of 340° C. The characteristics of the raw materials are shown in Table 2, and the product distribution and characteristics of the products are shown in Table 7.

[0117] [Table 7]

[0118] Comparative Example 8 Molecular sieve ZE and macroporous alumina (specific surface area is 302 m 2 / g, pore volume is 0.96 cm 3 The catalyst DC5 was obtained by kneading ZSM-5 (ZSM-5 mass percentage: 30 wt%) with alumina sol as a binder, extruding the mixture into a strand shape, molding it, and then drying and roasting it. The catalyst DC5 was obtained by impregnating the carrier with a nickel nitrate impregnation solution, drying and roasting it. The mass percentage of ZSM-5 was 30 wt%, the mass percentage of macroporous alumina was 50 wt%, the mass percentage of NiO was 10 wt%, and the remainder was the binder. 10 g of catalyst DC5 was placed in a fixed-bed reactor, and the reaction pressure was 6.0 MPa, the hydrogen / oil volume ratio was 500:1, and the liquid hourly space velocity was 10 h -1The hydrodewaxing reaction was carried out under hydrodewaxing conditions of 1000 kJ / min, 1000 kJ / min, and a reaction temperature of 340° C. The characteristics of the raw materials are shown in Table 2, and the product distribution and characteristics of the products are shown in Table 8.

[0119] [Table 8]

Claims

1. A ZSM-5 molecular sieve, characterized in that the total acid amount of pyridine measured by infrared spectroscopy is 0.03 to 0.40 mmol / g, the total acid amount of di-tert-butylpyridine measured by infrared spectroscopy is 0.002 to 0.02 mmol / g, the mesopore volume accounts for 10% to 20% of the total pore volume, and / or the volume of mesopores having a diameter of 2 to 10 nm accounts for 70% to 95% of the total mesopore volume.

2. The pyridine has a total acidity of 0.10 to 0.20 mmol / g as measured by infrared, and the di-tert-butylpyridine has a total acidity of 0.005 to 0.01 mmol / g as measured by infrared, and / or Outer surface SiO ２ / Al ２ O ３ Molar ratio and total SiO ２ / Al ２ O ３ 2. The molecular sieve according to claim 1, wherein the molar ratio of hydroxybenzoates to hydroxybenzoates is 2 to 100:

1.

3. The molecular sieve of claim 2, wherein the ratio of the SiO 2 / Al 2 O 3 molar ratio of the outer surface to the total SiO 2 / Al 2 O 3 molar ratio is 5-30:

1.

4. Outer surface SiO ２ / Al ２ O ３ the molar ratio is between 200 and 1000, and / or Total SiO ２ / Al ２ O ３ 2. The molecular sieve of claim 1, wherein the molar ratio is 30-100.

5. The SiO 2 / Al 2 O 3 molar ratio of the outer surface is 500 to 1000, and / or 2. The molecular sieve of claim 1, wherein the total SiO 2 / Al 2 O 3 molar ratio is 40-70.

6. (1) hydrothermally treating a raw ZSM-5 molecular sieve; Step (2) of removing non-framework aluminum in the molecular sieve obtained in step (1); Step (3) of impregnating the material obtained in step (2) with a pore channel protection liquid; Step (4) of treating the material obtained in step (3) with an organic acid; Step (5) of mixing the material obtained in step (4) with an aluminum removal silicon replenishment reagent to remove aluminum and replenish silicon; and (6) filtering, washing, drying and roasting the material obtained in step (5).

7. In step (1), The temperature of the hydrothermal treatment is 400 to 700°C, The duration of the hydrothermal treatment is 0.5 to 5 h, and / or The method according to claim 6, wherein the pressure of the hydrothermal treatment is 0.05 to 0.5 MPa.

8. In step (2), removing non-framework aluminum using a buffer solution that is a mixed solution of a weak acid and / or a weak base and their corresponding salts; the weak acid is an inorganic acid and / or an organic acid having a molecular size of less than 0.5 nm and capable of being removed without damaging the structure of the molecular sieve; the inorganic acid is one or more of phosphoric acid, carbonic acid, and boric acid; the salt of an inorganic acid is one or more of an ammonium phosphate, an ammonium carbonate, and an ammonium borate; the organic acid is selected from C2 to C6 monobasic or polybasic acids; The salt of the organic acid is selected from C2 to C6 monobasic or polybasic acid salts. The method of claim 6.

9. The organic acid is one or more of citric acid, formic acid, acetic acid, oxalic acid, propionic acid, malonic acid, butyric acid, and succinic acid; 9. The method of claim 8, wherein the salt of an organic acid is one or more of ammonium citrate, ammonium formate, ammonium acetate, ammonium oxalate, ammonium propionate, ammonium malonate, ammonium butyrate, and ammonium succinate.

10. The method described in claim 8, wherein the buffer solution is one or more of an oxalic acid-ammonium oxalate solution and an acetic acid-ammonium acetate solution.

11. the pH value of said buffer solution is in the range of 4.5 to 6.5; and / or the molar concentration of the acid in the buffer solution is 0.1 to 1.0 mol / L; and / or 9. The method of claim 8, wherein the liquid / solid volume ratio of the buffer solution to the molecular sieve obtained in step (1) is 3:1 to 10:

1.

12. The process of step (2) is as follows:

7. The method according to claim 6, comprising mixing and stirring the molecular sieve obtained in step (1) with a buffer solution, followed by solid-liquid separation.

13. In step (3), The pore channel protecting agent of the pore channel protecting solution is an inorganic alkali and / or an organic alkali having a molecular size of less than 0.5 nm and removable by roasting without damaging the structure of the molecular sieve; the pore channel protecting agent is one or more of ammonia water, ethylenediamine, propylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetramethylammonium bromide, and tetraethylammonium bromide; the pore channel protection liquid is one or more of an isopropylamine solution, a tetraethylammonium hydroxide solution, and a tetrapropylammonium hydroxide solution; and / or The method according to claim 6, wherein the concentration of the pore channel protection solution is 0.8 to 2.0 mol / L.

14. In step (3), the impregnation is an isovolumetric impregnation, and / or The method according to claim 6, wherein the impregnation temperature is 20 to 25°C.

15. In step (4), The organic acid has a molecular size of 0.55 nm to 2 nm and is an organic acid that can be removed by roasting without damaging the structure of the molecular sieve; 7. The method of claim 6, wherein the organic acid is one or more of 2-methylbenzoic acid, 2-methylbenzenesulfonic acid, 2,4-xylenesulfonic acid, 2,4-dimethylbenzoic acid, 1,2,5-trimethylbenzenesulfonic acid, and 1,2,5-trimethylbenzoic acid.

16. 7. The method of claim 6, wherein the treating process in step (4) comprises first mixing the material obtained in step (3) with water, and then adding an organic acid until the pH value of the solution is reduced to 8 or less.

17. In step (5), The aluminum-removing silicon replenisher of the aluminum-removing silicon replenisher reagent is one or more of fluorosilicic acid, fluorosilicic acid salts, silicon halides, and silicates; and / or The molar concentration of the aluminum-removing silicon-replenishing reagent is 0.3 to 1.0 mol / L; and / or 7. The method of claim 6, wherein the mass ratio of the material obtained in step (4) to the aluminum-removing silicon-replenishing reagent is 1:1 to 1:

5.

18. 7. The method of claim 6, wherein the operation of step (5) comprises heating the material obtained in step (4) to 60-100°C, continuously stirring, adding dropwise the aluminum-removing silicon-replenishing reagent, and continuing stirring for 60-120 minutes after the dropwise addition is completed.

19. Use of the molecular sieve according to any one of claims 1 to 5 as a carrier and / or catalytically active component.

20. A hydrotreating catalyst comprising the ZSM-5 molecular sieve according to any one of claims 1 to 5 and a hydrogenation active component.

21. A hydrodewaxing catalyst comprising the ZSM-5 molecular sieve according to any one of claims 1 to 5.

22. A hydrodewaxing catalyst comprising the ZSM-5 molecular sieve and a Group VIII metal component, wherein the content of the ZSM-5 molecular sieve is 30% to 90% based on the weight of the hydrodewaxing catalyst, and the content of the Group VIII metal component, calculated as an oxide, is 5% to 40%; Alternatively, the hydrodewaxing catalyst according to claim 21, comprising the ZSM-5 molecular sieve, alumina, and a Group VIII metal component, wherein the ZSM-5 molecular sieve content is 30% to 50%, the alumina content is 40% to 70%, and the Group VIII metal component content, calculated as oxide, is 5% to 40%, based on the weight of the hydrodewaxing catalyst.

23. 22. Use of the hydrodewaxing catalyst of claim 21 in the hydrodewaxing of oil products.

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