Zsm-5 molecular sieve, method for preparing and using the same, and hydroprocessing catalyst and application of the same

Abstract

The application provides a ZSM-5 molecular sieve, a preparation method and application thereof, a hydroprocessing catalyst, a hydrodewaxing catalyst and application thereof. The pyridine infrared total acid amount of the ZSM-5 molecular sieve is 0.03-0.40 mmol / g, the di-tert-butyl pyridine infrared total acid amount is 0.002-0.02 mmol / g; the mesopore volume of the ZSM-5 molecular sieve accounts for 10-20% of the total pore volume, and / or the mesopore volume of 2-10 nm in the ZSM-5 molecular sieve accounts for 70-95% of the total mesopore volume. The molecular sieve has obvious technical advantages as a carrier or an active component, for example, the hydrodewaxing catalyst prepared from the ZSM-5 molecular sieve can be used for oil product treatment to simultaneously improve the quality and yield of low-condensation oil products.

Description

[0001] Cross-reference to related applications

[0002] 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. Technical Field

[0003] This invention relates to the field of molecular sieves and their preparation, specifically to a ZSM-5 molecular sieve, its preparation method and application, and hydrogenation treatment catalysts and hydrodewaxing catalysts and their applications. Background Technology

[0004] In 1972, Mobile successfully synthesized the first molecular sieve belonging to the "Pentasil" family, named ZSM-5, using tetraethylammonium hydroxide as a template agent. Its emergence was a milestone in the development of molecular sieves. In 1978, Kokotailo et al. analyzed the structure of ZSM-5 molecular sieve, confirming that it has a three-dimensional double ten-membered ring pore structure, consisting of straight and sinusoidal channels. The two sets of ten-membered ring channels are orthogonal. The straight ten-membered ring channels are parallel to the b-axis with a pore size of 0.53 × 0.56 nm, while the sinusoidal ten-membered ring channels are parallel to the a-axis with a pore size of 0.51 × 0.55 nm. Their cell parameters are a = 2.017 nm, b = 1.996 nm, and c = 1.343 nm, respectively. This pore structure endows it with shape-selective catalytic properties. Hydrogenation dewaxing reaction utilizes the fact that the molecular dynamics of most cyclic hydrocarbons and isoparaffins are larger than the ten-membered ring channels of ZSM-5 molecular sieves, preventing them from entering the channel interior for reaction. This enables the selective cracking of low-temperature, poorly mobile chain hydrocarbons. However, the presence of acidity at the pore openings and outer surface of the ZSM-5 molecular sieve powder can lead to side reactions, affecting its catalytic performance.

[0005] To obtain catalysts with high para-selectivity and reaction stability, ZSM-5 molecular sieves must be modified. Silanization is a frequently used and relatively effective method for modifying the acidity of the outer surface of the molecular sieve. Current silanization methods include: (1) vacuum chemical vapor deposition; (2) flowing chemical vapor deposition; (3) liquid phase chemical impregnation; (4) reflux liquid phase deposition; and (5) chemical reaction deposition. Although the processes differ, the main purpose is to eliminate the acidic centers on the outer surface of the molecular sieve by loading amorphous silica onto it through deposition. However, traditional silanization methods require repeated, cyclic impregnation to eliminate the acidity, resulting in significant waste of silica ester and greatly reducing the efficiency of the modification process. While the improved chemical reaction deposition method increases modification efficiency and silica ester utilization, it requires special operations, making the process cumbersome and inevitably leading to pore blockage. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a ZSM-5 molecular sieve, its preparation method and applications, as well as a hydrotreating catalyst and a hydroponic dewaxing catalyst and its applications. This ZSM-5 molecular sieve has wide applications as a support or active component. For example, as a support, the catalyst prepared for hydroponic dewaxing in the blending of straight-run diesel with catalytic diesel and / or coking diesel can simultaneously improve the quality and yield of low-pour-point diesel.

[0007] In a first aspect, the present invention provides a ZSM-5 molecular sieve, wherein the total pyridine infrared spectral acidity of the ZSM-5 molecular sieve is 0.03–0.40 mmol / g, and the total di-tert-butylpyridine infrared spectral acidity is 0.002–0.02 mmol / g; the mesopore volume of the ZSM-5 molecular sieve accounts for 10%–20% of the total pore volume, and / or in the ZSM-5 molecular sieve, the mesopore volume of 2–10 nm accounts for 70%–95% of the total mesopore volume.

[0008] In a second aspect, the present invention provides a method for preparing the ZSM-5 molecular sieve described herein, the method comprising the following steps:

[0009] (1) Hydrothermal treatment of raw material ZSM-5 molecular sieve;

[0010] (2) Remove non-framework aluminum from the molecular sieve obtained in step (1);

[0011] (3) Impregnate the material obtained in step (2) with a channel protection liquid;

[0012] (4) The material obtained in step (3) is treated with organic acids;

[0013] (5) Mix the material obtained in step (4) with the dealuminizing and silicon replenishing reagent to perform dealuminizing and silicon replenishment;

[0014] (6) The material obtained in step (5) is filtered, washed, dried and roasted.

[0015] In a third aspect, the present invention provides the use of the molecular sieve as a support and / or an active component of a catalyst, preferably as a support for a hydrogenation catalyst.

[0016] In a fourth aspect, the present invention provides a hydrogenation catalyst, wherein the hydrogenation catalyst contains the ZSM-5 molecular sieve and the hydrogenation active component described herein.

[0017] In a fifth aspect, the present invention provides a hydrodewaxing catalyst containing the ZSM-5 molecular sieve described herein; preferably, the hydrodewaxing catalyst comprises the ZSM-5 molecular sieve and a Group VIII metal component, wherein, based on the weight of the catalyst, the content of the ZSM-5 molecular sieve is 30% to 90%, and the content of the Group VIII metal component, calculated as oxides, is 5% to 40%.

[0018] In a sixth aspect, the present invention provides the application of the hydrodewaxing catalyst of the present invention in hydrodewaxing of oil products; preferably, the oil product is a mixture of straight-run diesel oil and catalytic diesel oil and / or coking diesel oil.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. The ZSM-5 molecular sieve of this invention has a low total infrared acidity of di-tert-butylpyridine, which eliminates mesoporous acids and external surface acids while having a suitable mesoporous distribution. The ZSM-5 molecular sieve has a wide range of applications as a support or active component. For example, the catalyst prepared as a support can be used in the process of hydrodewaxing straight-run diesel blending and / or coking diesel to simultaneously improve the quality and yield of low-pour-point diesel.

[0021] 2. The preparation method of ZSM-5 molecular sieve of the present invention firstly obtains a certain amount of mesopores through hydrothermal treatment, then removes non-framework aluminum to make the pores more unobstructed, and then selectively removes acid centers in non-zigzag pores through pore protection. Most of the aluminum sites in non-zigzag pores are replaced by non-acidic silicon atoms under the action of aluminum removal and silicon replenishment agent, thus completely preserving the molecular sieve structure.

[0022] In a preferred embodiment of the present invention, a small number of acid centers on the outer surface and in the mesopores of the molecular sieve can be retained as needed, giving the molecular sieve better performance advantages. For example, when used as a hydrodewaxing catalyst, a small amount of polycyclic aromatic hydrocarbons that are easily adsorbed in the feedstock undergo hydrogenation and ring-opening at the weakly acidic sites in the mesopores and on the outer surface, thereby improving the quality of diesel. Monocyclic hydrocarbons and isomeric chain hydrocarbons with higher quality and lower pour points are retained in the product because they have poor competitive adsorption capacity and are difficult to enter the micropores of the ZSM-5 molecular sieve. Since n-alkanes have a weaker adsorption capacity than aromatics, they are not dominant in competitive adsorption outside the pores, and thus enter the micropores to undergo shape-selective cracking reactions, obtaining primary cracking products with lower pour points. The reduced acid centers on the outer surface prevent the cracking products from further cracking into smaller non-diesel components. The unobstructed pores allow the primary cracking products to diffuse out of the pores in a timely manner, reducing secondary cracking and ultimately significantly improving the yield of low-pour-point diesel. Attached Figure Description

[0023] Figure 1The images show the XRD patterns of commercially available ZSM-5 molecular sieve, ZSM-5 molecular sieve Z-T4 obtained in Example 4 of this invention, and molecular sieve ZB obtained in Comparative Example 1. Detailed Implementation

[0024] The following examples and comparative examples further illustrate the role and effect of the technical solution of the present invention, but the following examples do not constitute a limitation on the scope of protection of the present invention.

[0025] This invention provides a ZSM-5 molecular sieve, wherein the total pyridine infrared spectral acidity of the ZSM-5 molecular sieve is 0.03–0.40 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, 0.14 mmol / g, 0.15 mmol / g, 0.16 mmol / g, 0.17 mmol / g, 0.18 mmol / g, and 0.19 mmol / g. l / g, 0.20mmol / g, 0.21mmol / g, 0.22mmol / g, 0.23mmol / g, 0.24mmol / g, 0.25mmol / g, 0.26mmol / g, 0.27mmol / g, 0.28mmol / g, 0.29mmol / g, 0.30m mol / g, 0.31mmol / g, 0.32mmol / g, 0.33mmol / g, 0.34mmol / g, 0.35mmol / g, 0.36mmol / g, 0.37mmol / g, 0.38mmol / g, 0.39mmol / g, 0.40mmol / g, di-tert-butyl The total acidity of pyridylpyridine in infrared spectroscopy ranges from 0.002 to 0.02 mmol / g, for example, 0.002 mmol / g, 0.003 mmol / g, 0.004 mmol / g, 0.005 mmol / g, 0.006 mmol / g, 0.007 mmol / g, 0.008 mmol / g, 0.009 mmol / g, 0.010 mmol / g, 0.011 mmol / g, 0.012 mmol / g, 0.013 mmol / g, 0.014 mmol / g, 0.015 mmol / g, 0.016 mmol / g, 0.017 mmol / g, 0.018 mmol / g, 0.019 mmol / g. mmol / g, 0.020 mmol / g; the mesopore volume of the ZSM-5 molecular sieve accounts for 10% to 20% of the total pore volume, for example, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%; and / or in the ZSM-5 molecular sieve, the mesopore volume of 2 to 10 nm accounts for 70% to 95% of the total mesopore volume, 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%, 95%.

[0026] According to a preferred embodiment of the present invention, the total pyridine IR acidity of the ZSM-5 molecular sieve is 0.10–0.20 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 di-tert-butylpyridine IR acidity is 0.005–0.01 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.

[0027] According to a preferred embodiment of the present invention, the ratio of the molar ratio of SiO2 / Al2O3 on the outer surface of the ZSM-5 molecular sieve to the total molar ratio of SiO2 / Al2O3 in 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.

[0028] According to a preferred embodiment of the present invention, the molar ratio of SiO2 / Al2O3 on the outer surface of the ZSM-5 molecular sieve is 200 to 1000, preferably 500 to 1000.

[0029] According to a preferred embodiment of the present invention, the total SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 30 to 100, preferably 40 to 70.

[0030] 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.

[0031] According to a preferred embodiment of the present invention, in the ZSM-5 molecular sieve, the mesopore volume of 2-10 nm accounts for 70%-95% of the total mesopore volume.

[0032] Molecular sieves possessing the aforementioned properties of this invention can all achieve the objectives of this invention, and there are no special requirements for their preparation methods. According to a preferred embodiment of this invention, this invention provides a method for preparing the ZSM-5 molecular sieve described herein, the method comprising the following steps:

[0033] (1) Hydrothermal treatment of raw material ZSM-5 molecular sieve;

[0034] (2) Remove non-framework aluminum from the molecular sieve obtained in step (1);

[0035] (3) Impregnate the material obtained in step (2) with a channel protection liquid;

[0036] (4) The material obtained in step (3) is treated with organic acids;

[0037] (5) Mix the material obtained in step (4) with the dealuminizing and silicon replenishing reagent to perform dealuminizing and silicon replenishment;

[0038] (6) The material obtained in step (5) is filtered, washed, dried and roasted.

[0039] In this invention, the ZSM-5 molecular sieve raw material can be a commercially available product or a microporous hydrogen-form ZSM-5 molecular sieve prepared according to existing technology. Preferably, the properties of the ZSM-5 molecular sieve raw material are as follows: SiO2 / Al2O3 molar ratio 30-100, specific surface area 300-450 m² / g. 2 / g, pore volume 0.15~0.20cm³ 3 / g.

[0040] According to a preferred embodiment of the present invention, in step (1), the temperature of the hydrothermal treatment is 400-700°C, preferably 500-600°C.

[0041] According to the present invention, the hydrothermal treatment time is adjusted according to the temperature. Preferably, the hydrothermal treatment time is 0.5 to 5 hours, and more preferably 1 to 2 hours.

[0042] According to the present invention, the pressure of hydrothermal treatment is adjusted according to the temperature. For the present invention, the pressure of hydrothermal treatment is 0.05 to 0.5 MPa, preferably 0.1 to 0.3 MPa.

[0043] In this invention, the method for removing non-skeletal aluminum can be various, including but not limited to using a buffer solution for removing non-skeletal aluminum. The buffer solution refers to a mixed solution composed of a weak acid and its salt, a weak base and its corresponding salt, which can, to a certain extent, offset or reduce the influence of external strong acid or strong base on the pH of the solution, thereby maintaining the pH value of the solution relatively stable.

[0044] Unless otherwise specified, in this invention, "solution" refers to an aqueous solution.

[0045] In this invention, the weak acid is preferably an inorganic acid and / or an organic acid with a molecular size of less than 0.5 nm that can be removed by means such as calcination without damaging the molecular sieve structure.

[0046] According to a preferred embodiment of the present invention, the inorganic acid is one or more selected from phosphoric acid, carbonic acid, and boric acid.

[0047] According to a preferred embodiment of the present invention, the inorganic acid salt is an ammonium salt of phosphoric acid, carbonic acid, or boric acid.

[0048] According to a preferred embodiment of the present invention, the organic acid is selected from C2-C6 monocarboxylic or polycarboxylic acids, preferably one or more of citric acid, formic acid, acetic acid, oxalic acid, propionic acid, malonic acid, butyric acid, and succinic acid.

[0049] According to a preferred embodiment of the present invention, the organic acid salt is selected from monocarboxylic acids or polycarboxylic acid salts of C2-C6, preferably one or more of citric acid, formic acid, acetic acid, oxalic acid, propionic acid, malonic acid, butyric acid and ammonium salts of succinic acid.

[0050] According to a preferred embodiment of the present invention, more preferably, the buffer solution is one or more of oxalic acid-ammonium oxalate solution and acetic acid-ammonium acetate solution.

[0051] According to a preferred embodiment of the present invention, the buffer solution is acidic, and preferably, the pH value of the buffer solution is in the range of 4.5 to 6.5.

[0052] According to a 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.

[0053] In this invention, the amount of buffer solution can be selected from a wide range. According to a preferred embodiment of this invention, the liquid-to-solid volume ratio of the buffer solution to the molecular sieve obtained in step (1) is 3:1 to 10:1.

[0054] According to a preferred embodiment of the present invention, 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 operation 2 to 4 times; according to the present invention, preferably, the processing temperature is 40 to 80°C, and the processing time is adjusted according to the temperature, preferably the processing time is 0.5 to 3 hours.

[0055] In this invention, the pore protection agent of the pore protection liquid is an inorganic or organic base with a molecular size of less than 0.5 nm that can be easily removed by means such as calcination without damaging the molecular sieve structure, such as one or more of ammonia, ethylenediamine, propylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetramethylammonium bromide, and tetraethylammonium bromide.

[0056] According to a preferred embodiment of the present invention, in step (3), the pore protection agent of the pore protection liquid is one or more of isopropylamine solution, tetramethylammonium hydroxide, tetraethylammonium hydroxide solution, and tetrapropylammonium hydroxide.

[0057] According to a preferred embodiment of the present invention, the pore protection liquid is preferably an aqueous solution of a pore protection agent, and is more preferably one or more of isopropylamine solution, tetraethylammonium hydroxide solution, and tetrapropylammonium hydroxide solution.

[0058] According to a preferred embodiment of the present invention, preferably, the concentration of the pore protection liquid is 0.8 to 2.0 mol / L.

[0059] In this invention, there are no special requirements for the impregnation method. For this invention, it is preferred that the impregnation be an equal volume impregnation.

[0060] According to a preferred embodiment of the present invention, the impregnation treatment temperature is 20-25°C.

[0061] In this invention, in step (4), the organic acid is preferably an organic acid with a molecular size between 0.55 nm and 2 nm that is easily removed by means such as calcination that do not damage the molecular sieve structure. For example, one or more of C7-C10 organic acids.

[0062] 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-dimethylbenzenesulfonic acid, 2,4-dimethylbenzoic acid, 1,2,5-trimethylbenzenesulfonic acid, and 1,2,5-trimethylbenzoic acid.

[0063] According to a preferred embodiment of the present invention, in step (4), the organic acid is further preferably one or more of 2,4-dimethylbenzenesulfonic acid and 2,4-dimethylbenzoic acid.

[0064] According to a preferred embodiment of the present invention, the process of step (4) includes: first mixing the material obtained in step (3) with water, preferably the liquid-to-solid volume ratio of water to the material obtained in step (3) is 2:1 to 6:1; then adding organic acid until the pH value of the solution drops below 8, preferably 6.5 to 7.5.

[0065] In this invention, the range of types of dealuminizing and silicon-replenishing agents in step (5) is relatively wide. According to a preferred embodiment of this invention, the dealuminizing and silicon-replenishing agent is one or more of fluorosilicic acid, fluorosilicates (including but not limited to ammonium hexafluorosilicate, fluorosilicic acid, sodium fluorosilicate), silicon halides (including but not limited to silicon tetrachloride, silicon tetrafluoride), and silicate esters (including but not limited to tetraethyl orthosilicate). Preferably, it is one or more of ammonium hexafluorosilicate, fluorosilicic acid, sodium fluorosilicate, silicon tetrachloride, silicon tetrafluoride, and tetraethyl orthosilicate. More preferably, the dealuminizing and silicon-replenishing agent is at least one of ammonium hexafluorosilicate solution and tetraethyl orthosilicate solution.

[0066] According to a preferred embodiment of the present invention, the molar concentration of the dealumination and silicon replenishment reagent is 0.3 to 1.0 mol / L.

[0067] In this invention, the amount of the dealuminizing and silicon-replenishing reagent can be selected from a wide range. According to a preferred embodiment of this invention, the mass ratio of the material obtained in step (4) to the dealuminizing and silicon-replenishing reagent is 1:1 to 1:5.

[0068] According to a preferred embodiment of the present invention, in step (5), the mixing temperature is 60 to 100°C.

[0069] 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 and stirring continuously, adding a dealuminating and silicon-replenishing reagent dropwise, and continuing to stir for 60-120 minutes after the addition is completed.

[0070] According to a preferred embodiment of the present invention, preferably, in step (6), the filtration and washing can be carried out using conventional methods in the art, the drying temperature is 100℃~150℃, the drying time is 2~4h, the calcination temperature is 400℃~600℃, and the calcination time is 3~5h.

[0071] According to the present invention, the use of the molecular sieve described herein as a support and / or an active component of a catalyst is provided, preferably as a support for a hydrogenation catalyst.

[0072] According to the present invention, a hydrotreating catalyst is provided, the hydrotreating catalyst comprising the ZSM-5 molecular sieve described in the present invention and a hydrotreating active component; preferably, the hydrotreating active component is selected from one or more of group VIB, VIIB, and VIII metals, and more preferably from one or more of Pt, Pd, Ni, W, Mo, and Co.

[0073] According to the present invention, a hydrogen dewaxing catalyst is provided, which contains the ZSM-5 molecular sieve described in the present invention.

[0074] According to a preferred embodiment of the present invention, preferably, the hydrodewaxing catalyst comprises the ZSM-5 molecular sieve and a Group VIII metal component, wherein, based on the weight of the catalyst, the content of the ZSM-5 molecular sieve is 30% to 90%, and the content of the Group VIII metal component, calculated as oxides, is 5% to 40%.

[0075] This invention provides the application of the hydrodewaxing catalyst of this invention in hydrodewaxing of oil products; preferably, the oil product is a mixture of straight-run diesel, catalytic diesel and / or coking diesel.

[0076] According to a preferred embodiment of the present invention, the outer surface SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 200-1000, the total SiO2 / Al2O3 molar ratio is 30-100, the total pyridine infrared acidity is 0.03-0.40 mmol / g, and the total di-tert-butylpyridine infrared acidity is 0.002-0.02 mmol / g; the mesoporous pore volume of the ZSM-5 molecular sieve accounts for 10%-20% of the total pore volume.

[0077] According to a preferred embodiment of the present invention, preferably, the molar ratio of SiO2 / Al2O3 on the outer surface of the ZSM-5 molecular sieve is 500-1000, and the molar ratio of total SiO2 / Al2O3 is 40-70.

[0078] According to a preferred embodiment of the present invention, preferably, the total pyridine infrared acidity of the ZSM-5 molecular sieve is 0.10-0.20 mmol / g; and the total pyridine infrared acidity is 0.005-0.01 mmol / g.

[0079] According to a preferred embodiment of the present invention, preferably, the mesopores in the ZSM-5 molecular sieve are concentrated in the range of 2–10 nm, wherein the mesopore volume of 2–10 nm accounts for 70%–95% of the total mesopore volume. In the present invention, mesopores refer to pores with a diameter of 2–50 nm.

[0080] According to a preferred embodiment of the present invention, a method for preparing ZSM-5 molecular sieve is provided, comprising the following steps:

[0081] (1) Hydrothermal treatment of ZSM-5 molecular sieve;

[0082] (2) Remove non-framework aluminum from the molecular sieve obtained in step (1);

[0083] (3) Impregnate the material obtained in step (2) with a channel protection liquid;

[0084] (4) The material obtained in step (3) is treated with organic acids;

[0085] (5) Mix the material obtained in step (4) with the dealuminizing and silicon replenishing reagent to perform dealuminizing and silicon replenishment;

[0086] (6) The material obtained in step (5) is filtered, washed, dried and calcined to obtain ZSM-5 molecular sieve.

[0087] According to a preferred embodiment of the present invention, preferably, in step (1), the temperature of the hydrothermal treatment is 400-700°C, preferably 500-600°C, the time is 0.5-5h, preferably 1-2h, and the pressure is 0.05-0.5MPa, preferably 0.1-0.3MPa.

[0088] According to a preferred embodiment of the present invention, preferably, in step (2), the method for removing non-skeletal aluminum can be a buffer solution method. The buffer solution used is one or more of oxalic acid-ammonium oxalate solution and acetate-ammonium acetate solution. The pH value of the buffer solution is in the range of 4.5 to 6.5, preferably 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.

[0089] According to a preferred embodiment of the present invention, preferably, in step (2), the specific processing procedure is as follows: the molecular sieve obtained in step (1) is mixed with a buffer solution and stirred, the processing temperature is 40-80°C, the processing time is 0.5-3h, and then solid-liquid separation (e.g., vacuum filtration) is performed; and the above operation is repeated 2-4 times.

[0090] According to a preferred embodiment of the present invention, preferably, in step (3), the pore protection solution is one or more of isopropylamine solution, tetraethylammonium hydroxide solution, tetrapropylammonium hydroxide solution, etc. The concentration of the pore protection solution is 0.8 to 2.0 mol / L, preferably 1.1 to 1.5 mol / L.

[0091] According to a preferred embodiment of the present invention, preferably, in step (3), the impregnation is an equal-volume impregnation. The impregnation treatment temperature is room temperature, generally 20-25°C.

[0092] According to a preferred embodiment of the present invention, preferably, in step (4), the organic acid is one or more of 2,4-dimethylbenzenesulfonic acid and 2,5-dimethylbenzoic acid.

[0093] According to a preferred embodiment of the present invention, the specific operation is as follows: first, the material obtained in step (3) is mixed with water, wherein the liquid-solid volume ratio of 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 drops below 8, preferably 6.5 to 7.5.

[0094] According to a preferred embodiment of the present invention, preferably, in step (5), the dealumination and silicon replenishment reagent is at least one of ammonium hexafluorosilicate solution, tetraethyl orthosilicate solution, etc. The molar concentration of the dealumination and silicon replenishment reagent is 0.3 to 1.0 mol / L. The mass ratio of the material obtained in step (4) to the dealumination and silicon replenishment reagent is 1:1 to 1:5. The mixing temperature is 60 to 100°C.

[0095] According to a preferred embodiment of the present invention, preferably, step (5) specifically involves: rapidly heating the material obtained in step (4) to 60–100°C while continuously stirring, adding a dealumination and silicon replenishment reagent dropwise, and continuing stirring for 60–120 min after the addition is completed. The dropwise addition rate does not exceed 0.5 mL / min·g of the material obtained in step (4); preferably, it is 0.2–0.4 mL / min·g of the material obtained in step (4).

[0096] According to a preferred embodiment of the present invention, preferably, in step (6), the filtration and washing can be carried out using conventional methods in the art, the drying temperature is 100℃~150℃, the drying time is 2~4h, the calcination temperature is 400℃~600℃, and the calcination time is 3~5h.

[0097] According to a preferred embodiment of the present invention, a hydrogen dewaxing catalyst is provided, comprising the above-mentioned ZSM-5 molecular sieve.

[0098] According to a preferred embodiment of the present invention, the hydrodewaxing catalyst preferably comprises the above-mentioned ZSM-5 molecular sieve and a Group VIII metal component, wherein, based on the weight of the catalyst, the content of the ZSM-5 molecular sieve is 30% to 90%, preferably 40% to 70%, and the content of the Group VIII metal component, calculated as oxides, is 5% to 40%, preferably 10% to 30%.

[0099] According to a preferred embodiment of the present invention, preferably, the hydrodewaxing catalyst comprises the ZSM-5 molecular sieve, alumina, and a Group VIII metal component, wherein, based on the weight of the catalyst, 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 oxides, is 5% to 40%.

[0100] According to a preferred embodiment of the present invention, preferably, the Group VIII metal is cobalt and / or nickel.

[0101] According to a preferred embodiment of the present invention, the present invention provides an application of the above-mentioned hydrodewaxing catalyst in hydrodewaxing of feedstock oil.

[0102] According to a preferred embodiment of the present invention, the application preferably includes: reacting feedstock oil in the presence of hydrogen under the action of the above-mentioned hydrodewaxing catalyst to obtain low-pour-point diesel oil.

[0103] According to a preferred embodiment of the present invention, preferably, in the application, the reaction conditions for hydrodewaxing are as follows: reaction pressure of 5.0–8.0 MPa, hydrogen-to-oil volume ratio of 400:1–600:1, and liquid hourly space velocity of 0.5–2 h⁻¹. -1 The reaction temperature is 280–400℃.

[0104] According to a preferred embodiment of the present invention, preferably, the feedstock is a mixture of straight-run diesel oil, catalytic diesel oil, and / or coking diesel oil. In the feedstock, the total blending amount of catalytic diesel oil and / or coking diesel oil is 20%–40%, the wax (n-alkanes with more than 20 carbon atoms) content is 5%–15%, and the polycyclic aromatic hydrocarbon content is 10%–30%. The distillation range of the feedstock is typically 150–400°C.

[0105] In this invention, unless otherwise specified, all percentages (%) in the embodiments and comparative examples refer to mass fractions.

[0106] In this invention, the SiO2 / Al2O3 molar ratio on the outer surface was determined by X-ray photoelectron spectroscopy (XPS). The elemental composition and state of the catalyst surface were determined using a Thermofisher Multilab2000 electron spectrometer, with Mg Kα as the excitation source and a cathode voltage and current of 13 kV and 20 mA, respectively. The electron binding energy was calibrated using C1s (284.6 eV).

[0107] In this invention, the total SiO2 / Al2O3 molar ratio was obtained by X-ray fluorescence spectroscopy (XRF) analysis using a ZSX100e X-ray fluorescence spectrometer with Kα spectral line, LiF1 crystal, Rh target material, SC scintillation detector, 20s timing, and vacuum optical atmosphere.

[0108] In this invention, the specific surface area, pore volume, and pore distribution were measured using the following method: an ASAP 2420 cryogenic liquid nitrogen physical adsorption instrument manufactured by Microlithics, Inc. was used, with a pretreatment temperature of 300°C and a pretreatment time of 4 hours.

[0109] In this invention, the pyridine infrared determination method is as follows: Powdered ZSM-5 molecular sieve is compressed into tablets, vacuumed, and degassed at 450°C for 2 hours. After the temperature drops to room temperature, pyridine molecules are used as probe molecules to measure the infrared spectrum of chemical desorption, and the adsorption amount is calculated.

[0110] In this invention, the total infrared acidity of di-tert-butylpyridine refers to the total acidity with a kinetic diameter of [missing information]. The 2,6-di-tert-butylpyridine molecule can contact protic acids. The infrared spectroscopy method for determining 2,6-di-tert-butylpyridine is as follows: Powdered ZSM-5 molecular sieve is compressed into tablets, vacuumed, and degassed at 450℃ for 2 hours. After the temperature drops to room temperature, 2,6-di-tert-butylpyridine molecules are used as probe molecules to measure their chemical desorption infrared spectrum, and the adsorption amount is calculated.

[0111] The ZSM-5 raw powder involved in the embodiments and comparative examples of this invention is a commercially available product, which is a microporous hydrogen-form ZSM-5 molecular sieve. The properties of the ZSM-5 are as follows: specific surface area is 405 m². 2 / g, pore volume is 0.182cm³ 3 / g, water absorption rate is 55%, SiO2 / Al2O3 ratio (molar) is 31.2.

[0112] Example 1

[0113] 30g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 500℃ and 0.1MPa pressure for 2h. The resulting material was placed in 300mL of an oxalic acid-ammonium oxalate solution with a pH of 6.0, wherein the molar concentration of oxalic acid was 0.3mol / L. The mixture was stirred and heated to 60℃, held for 30min, and then filtered. This process was repeated 3 times. Then, an equal volume of 16.5mL of 1.1mol / L isopropylamine solution was used for impregnation, and the mixture was allowed to stand for 10min. 170mL of water was added, and 2,5-dibenzenesulfonic acid was added dropwise until the pH reached 6.5. The mixture was stirred and heated to 60℃. 90mL of 0.3mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.2mL / min·g using a peristaltic pump, while the temperature was maintained at 60℃ and the mixture was stirred continuously for 90min. The filter cake was filtered while hot, and 300 mL of water was added to it. The mixture was heated to 60 °C and kept at that temperature for 20 min. The filter cake was then dried at 120 °C for 24 h and calcined at 500 °C for 3 h. The resulting molecular sieve was named Z-T1.

[0114] Example 2

[0115] 30g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 530℃ and 0.1MPa pressure for 2h. The resulting material was placed in 300mL of an acetic acid-ammonium acetate solution with a pH of 6.0, wherein the molar concentration of acetic acid was 0.2mol / L. The mixture was stirred and heated to 60℃, held for 30min, and then filtered. This process was repeated 3 times. Then, an equal volume of 16.5mL of a 1.2mol / L tetraethylammonium hydroxide solution was used for impregnation. After standing for 10min, 170mL of water was added, and 2,5-xylenecarboxylic acid was added dropwise until the pH reached 7.0. The mixture was stirred and heated to 65℃. 90mL of a 0.5mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.2mL / min·g using a peristaltic pump. The temperature was maintained at 65℃ and the mixture was stirred continuously for 90min. The filter cake was filtered while hot, and 300 mL of water was added to it. The mixture was heated to 60 °C and kept at that temperature for 20 min. The filter cake was then dried at 120 °C for 24 h and calcined at 500 °C for 3 h. The resulting molecular sieve was named Z-T2.

[0116] Example 3

[0117] 30g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 550℃ and 0.1MPa pressure for 2h. The resulting material was placed in 300mL of an oxalic acid-ammonium oxalate solution with a pH of 5.5, wherein the oxalic acid molar concentration was 0.4mol / L. The mixture was stirred and heated to 70℃, maintained for 30min, and then filtered. This process was repeated 3 times. The resulting material was then impregnated with an equal volume of 16.5mL of a 1.2mol / L tetrapropylammonium hydroxide solution, allowed to stand for 10min, and 170mL of water was added. 2,4-dibenzenesulfonic acid was added dropwise until the pH reached 6.5. The mixture was stirred and heated to 65℃. 90mL of a 0.6mol / L tetraethyl orthosilicate solution was added dropwise at a rate of 0.3mL / min·g using a peristaltic pump. The temperature was maintained at 65℃ and the mixture was stirred continuously for 90min. The filter cake was filtered while hot, and 300 mL of water was added to it. The mixture was heated to 60 °C and maintained for 20 min. The filter cake was then filtered while hot and dried at 120 °C for 24 h. After drying at 500 °C for 3 h, the resulting molecular sieve was named Z-T3.

[0118] Example 4

[0119] 30g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 550℃ and 0.15MPa pressure for 2h. The resulting material was placed in 300mL of an oxalic acid-ammonium oxalate solution with a pH of 5.5 and an oxalic acid concentration of 0.4mol / L. The mixture was stirred and heated to 80℃, maintained for 30min, and then filtered. This process was repeated 3 times. The resulting material was then impregnated with an equal volume of 16.5mL of a 1.2mol / L isopropylamine solution. After standing for 10min, 170mL of water was added, and 2,4-dibenzenesulfonic acid was added dropwise until the pH reached 7.0. The mixture was stirred and heated to 65℃. 90g of a 0.6mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.3mL / min·g using a peristaltic pump. The temperature was maintained at 65℃ and the mixture was stirred continuously for 90min. The filter cake was filtered while hot, and 300 mL of water was added to it. The mixture was heated to 60 °C and kept at that temperature for 20 min. The filter cake was then dried at 120 °C for 24 h and calcined at 500 °C for 3 h. The resulting molecular sieve was named Z-T4.

[0120] Example 5

[0121] 30g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 550℃ and 0.15MPa pressure for 2h. The resulting material was placed in 300mL of an oxalic acid-ammonium oxalate solution with a pH of 5.0 and an oxalic acid concentration of 0.3mol / L. The mixture was stirred and heated to 60℃, maintained for 30min, and then filtered. This process was repeated 3 times. The resulting material was then impregnated with an equal volume of 16.5mL of a 1.2mol / L isopropylamine solution. After standing for 10min, 170mL of water was added, and 2,4-xylenecarboxylic acid was added dropwise until the pH reached 7.0. The mixture was stirred and heated to 65℃. 90mL of a 0.6mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.3mL / min·g using a peristaltic pump. The temperature was maintained at 65℃ and the mixture was stirred continuously for 90min. The filter cake was filtered while hot, and 300 mL of water was added to it. The mixture was heated to 60 °C and maintained for 20 min. The filter cake was then filtered while hot and dried at 120 °C for 24 h. After drying at 500 °C for 3 h, the resulting molecular sieve was named Z-T5.

[0122] Example 6

[0123] 30g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 550℃ and 0.15MPa pressure for 2h. The resulting material was placed in 300mL of an acetic acid-ammonium acetate solution with a pH of 5.0 and an acetic acid concentration of 0.3mol / L. The mixture was stirred and heated to 60℃, maintained for 30min, and then filtered. This process was repeated 3 times. The resulting material was then impregnated with an equal volume of 16.5mL of a 1.3mol / L tetraethylammonium hydroxide solution. After standing for 10min, 170mL of water was added, and 2,4-dibenzenesulfonic acid was added dropwise until the pH reached 7.5. The mixture was stirred and heated to 65℃. 90mL of a 0.6mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.3mL / min·g using a peristaltic pump. The temperature was maintained at 65℃ and the mixture was stirred continuously for 90min. The filter cake was filtered while hot, and 300 mL of water was added to it. The mixture was heated to 60 °C and kept at that temperature for 20 min. The filter cake was then dried at 120 °C for 24 h and calcined at 500 °C for 3 h. The resulting molecular sieve was named Z-T6.

[0124] Example 7

[0125] 30g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 570℃ and 0.15MPa pressure for 2h. The resulting material was placed in 300mL of an acetic acid-ammonium acetate solution with a pH of 5.0 and an acetic acid concentration of 0.5mol / L. The mixture was stirred and heated to 60℃, maintained for 30min, and then filtered. This process was repeated 3 times. The resulting material was then impregnated with an equal volume of 16.5mL of a 1.5mol / L isopropylamine solution. After standing for 10min, 170mL of water was added, and 2,4-xylenecarboxylic acid was added dropwise until the pH reached 7.5. The mixture was stirred and heated to 65℃. 90mL of a 0.8mol / L tetraethyl orthosilicate solution was added dropwise at a rate of 0.4mL / min·g using a peristaltic pump. The temperature was maintained at 65℃ and the mixture was stirred continuously for 90min. The filter cake was filtered while hot, and 300 mL of water was added to it. The mixture was heated to 60 °C and kept at that temperature for 20 min. The filter cake was then dried at 120 °C for 24 h and calcined at 500 °C for 3 h. The resulting molecular sieve was named Z-T7.

[0126] Example 8

[0127] 30g of commercially available ZSM-5 raw powder was placed in a hydrothermal treatment furnace and treated at 570℃ and 0.2MPa pressure for 2h. The resulting material was placed in 300mL of an oxalic acid-ammonium oxalate solution with a pH of 5.0 and an oxalic acid concentration of 0.5mol / L. The mixture was stirred and heated to 60℃, maintained for 30min, and then filtered. This process was repeated 3 times. The resulting material was then impregnated with an equal volume of 16.5mL of a 1.5mol / L isopropylamine solution. After standing for 10min, 170mL of water was added, and 2,4-xylenecarboxylic acid was added dropwise until the pH reached 7.5. The mixture was stirred and heated to 65℃. 90mL of a 1.0mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.4mL / min·g using a peristaltic pump. The temperature was maintained at 65℃ and the mixture was stirred continuously for 90min. The filter cake was filtered while hot, and 300 mL of water was added to it. The mixture was heated to 60 °C and kept at that temperature for 20 min. The filter cake was then dried at 120 °C for 24 h and calcined at 500 °C for 3 h. The resulting molecular sieve was named Z-T8.

[0128] Comparative Example 1

[0129] 30g of commercially available ZSM-5 raw powder was placed in a hydrothermal furnace and treated at 550℃ and 0.15MPa pressure for 2h. The resulting material was placed in 300mL of oxalic acid-ammonium oxalate solution with a pH of 5.0 and a molar concentration of 0.3mol / L of oxalic acid. The mixture was stirred and heated to 60℃ and maintained for 30min before filtration. This process was repeated 3 times. The filter cake was dried at 120℃ for 24h and then calcined at 500℃ for 3h. The resulting molecular sieve was named ZB.

[0130] Comparative Example 2

[0131] 30g of commercially available ZSM-5 raw powder was placed in a hydrothermal furnace and treated at 550℃ and 0.15MPa pressure for 2h. The resulting material was placed in 300mL of an oxalic acid-ammonium oxalate solution with a pH of 5.0 and an oxalic acid concentration of 0.3mol / L. The mixture was stirred and heated to 60℃, maintained for 30min, and then filtered. This process was repeated three times. 90mL of a 0.6mol / L ammonium hexafluorosilicate solution was then added dropwise using a peristaltic pump at a rate of 0.3mL / min·g, while maintaining the temperature at 65℃ and stirring continuously for 90min. The mixture was filtered while hot, and the filter cake was dried at 120℃ for 24h and then calcined at 500℃ for 3h. The resulting molecular sieve was named ZC.

[0132] Comparative Example 3

[0133] 30g of commercially available ZSM-5 raw powder was placed in a hydrothermal furnace and treated at 550℃ and 0.15MPa pressure for 2h. The resulting material was impregnated with 16.5mL of 0.6mol / L isopropylamine solution, allowed to stand for 10min, and then 170mL of water was added. 2,4-xylenecarboxylic acid was added dropwise until the pH reached 7.0. The mixture was stirred and heated to 65℃. 90mL of 0.6mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.3mL / min·g using a peristaltic pump, while maintaining the temperature at 65℃ and stirring continuously for 90min. The mixture was filtered while hot, and 300mL of water was added to the filter cake. The mixture was heated to 60℃ and maintained for 20min, then filtered while hot. The filter cake was dried at 120℃ for 24h and then calcined at 500℃ for 3h. The resulting molecular sieve was named ZD.

[0134] Comparative Example 4

[0135] 30g of commercially available ZSM-5 raw powder was stirred and heated to 65℃. 180mL of 1.0mol / L ammonium hexafluorosilicate solution was added dropwise at a rate of 0.4mL / min·g using a peristaltic pump. The temperature was maintained at 65℃ and stirring was continued for 90min. The mixture was filtered while hot. The filter cake was dried at 120℃ for 24h and then calcined at 500℃ for 3h. The resulting molecular sieve was named ZE.

[0136] Table 1. Characterization results of the molecular sieves obtained in the examples and comparative examples.

[0137]

[0138]

[0139] Example 9

[0140] The method of Example 5 was followed, except that a citric acid-ammonium citrate solution with a pH of 5.0 was used to obtain a molecular sieve, named Z-T9.

[0141] Example 10

[0142] Following the method of Example 5, except that the pore protection solution was ammonia water with a concentration of 1.2 mol / L, a molecular sieve was obtained and named Z-T10.

[0143] Example 11

[0144] The method of Example 5 is followed, except that the organic acid in step (4) is 2-methylbenzenesulfonic acid, and a molecular sieve named Z-T11 is obtained.

[0145] Example 12

[0146] Following the method of Example 5, except that the dealumination and silicon replenishment reagent was a 0.6 mol / L fluorosilicic acid solution, a molecular sieve was obtained and named Z-T12.

[0147] Example 13

[0148] Catalysts were prepared using molecular sieves Z-T1 to Z-T12 obtained in Examples 1-12, respectively. The preparation process involved reacting the calcined molecular sieves with macroporous alumina (specific surface area of ​​302 m²). 2 / g, pore volume 0.96cm 3 After mixing, extruding, and molding the aluminum sol binder (g), the carrier is obtained by drying and calcining. The carrier is then impregnated with nickel nitrate impregnation solution, and then dried and calcined to obtain the catalyst, which is designated as C1-C12. The molecular sieve has a mass fraction of 30 wt%, the macroporous alumina has a mass fraction of 50 wt%, the NiO has a mass fraction of 10 wt%, and the remainder is binder.

[0149] Take 10g of each of the catalysts C1-C12 and place them in a fixed-bed reactor. The reaction is carried out at a pressure of 6.0MPa, a hydrogen-to-oil volume ratio of 500:1, and a liquid hourly space velocity of 10h⁻¹. -1 The reaction was carried out at a temperature of 320℃, and the properties of the raw materials are shown in Table 2. The product distribution and properties are shown in Table 3.

[0150] Table 2 Properties of Oil Products

[0151] Types of raw materials Daqing Straight Diesel Catalytic Oil <![CDATA[Density (20 °C), kg / m 3 > 864.0 Distillation range, °C 165～365 Pour point, ℃ 18 Wax content, wt% 11.0 Polycyclic aromatic hydrocarbon content, wt% 15 Pour point, ℃ 5

[0152] Table 3. Application results of catalysts in each example.

[0153]

[0154] Comparative Example 4

[0155] Commercially available ZSM-5 molecular sieve and macroporous alumina (specific surface area 302m²) 2 / g, pore volume 0.96cm 3 The carrier is obtained by mixing, extruding, and molding the aluminum sol binder (g), followed by drying and calcination. The carrier is then impregnated with nickel nitrate impregnation solution, followed by drying and calcination to obtain catalyst DC1. The catalyst DC1 is composed of ZSM-5 (30 wt%), macroporous alumina (50 wt%), NiO (10 wt%), and the remainder is binder.

[0156] 10g of catalyst DC1 was placed in a fixed-bed reactor and reacted at a reaction pressure of 6.0MPa, a hydrogen-to-oil volume ratio of 500:1, and a liquid hourly space velocity of 10h⁻¹. -1The reaction was carried out under hydrogen decondensation conditions at a reaction temperature of 340℃. The properties of the raw materials are shown in Table 2, and the product distribution and properties are shown in Table 4.

[0157] Table 4. Application results of catalysts prepared using commercially available molecular sieves

[0158]

[0159] Comparative Example 5

[0160] Molecular sieve ZB and macroporous alumina (specific surface area 302 m²) 2 / g, pore volume 0.96cm 3 The carrier is obtained by mixing, extruding, and molding the aluminum sol binder (g), followed by drying and calcination. The carrier is then impregnated with nickel nitrate impregnation solution, followed by drying and calcination to obtain catalyst DC2. The carrier contains 30 wt% ZSM-5, 50 wt% macroporous alumina, 10 wt% NiO, and the remainder is binder.

[0161] 10g of catalyst DC2 was placed in a fixed-bed reactor and reacted at a reaction pressure of 6.0MPa, a hydrogen-to-oil volume ratio of 500:1, and a liquid hourly space velocity of 10h⁻¹. -1 The reaction was carried out under hydrogen decondensation conditions at a reaction temperature of 340℃. The properties of the raw materials are shown in Table 2, and the product distribution and properties are shown in Table 5.

[0162] Table 5. Application results of catalysts prepared using ZB molecular sieves

[0163]

[0164] Comparative Example 6

[0165] Molecular sieve ZC and macroporous alumina (specific surface area 302 m²) 2 / g, pore volume 0.96cm 3 The carrier is obtained by mixing, extruding, and molding the aluminum sol binder (g), followed by drying and calcination. The carrier is then impregnated with nickel nitrate impregnation solution, followed by drying and calcination to obtain catalyst DC3. The carrier contains 30 wt% ZSM-5, 50 wt% macroporous alumina, 10 wt% NiO, and the remainder is binder.

[0166] 10g of catalyst DC3 was placed in a fixed-bed reactor and reacted at a reaction pressure of 6.0MPa, a hydrogen-to-oil volume ratio of 500:1, and a liquid hourly space velocity of 10h⁻¹. -1 The reaction was carried out under hydrogen decondensation conditions at a reaction temperature of 340℃. The properties of the raw materials are shown in Table 2, and the product distribution and properties are shown in Table 6.

[0167] Table 6. Application results of catalysts prepared using ZC molecular sieves

[0168]

[0169] Comparative Example 7

[0170] Molecular sieve ZD and macroporous alumina (specific surface area 302 m²) 2 / g, pore volume 0.96cm 3 The carrier is obtained by mixing, extruding, and molding the aluminum sol binder (g), followed by drying and calcination. The carrier is then impregnated with nickel nitrate impregnation solution, followed by drying and calcination to obtain catalyst DC4. The catalyst consists of ZSM-5 (30 wt%), macroporous alumina (50 wt%), NiO (10 wt%), and the remainder is binder.

[0171] 10g of catalyst DC4 was placed in a fixed-bed reactor and reacted at a pressure of 6.0MPa, a hydrogen-to-oil volume ratio of 500:1, and a liquid hourly space velocity of 10h⁻¹. -1 The reaction was carried out under hydrogen decondensation conditions at a reaction temperature of 340℃. The properties of the raw materials are shown in Table 2, and the product distribution and properties are shown in Table 7.

[0172] Table 7 Application results of catalysts prepared using ZD molecular sieves

[0173]

[0174] Comparative Example 8

[0175] Molecular sieve ZE and macroporous alumina (specific surface area 302 m²) 2 / g, pore volume 0.96cm 3 The carrier is obtained by mixing, extruding, and molding the aluminum sol binder (g), followed by drying and calcination. The carrier is then impregnated with nickel nitrate impregnation solution, followed by drying and calcination to obtain catalyst DC5. The catalyst DC5 is composed of ZSM-5 (30 wt%), macroporous alumina (50 wt%), NiO (10 wt%), and the remainder is binder.

[0176] 10g of catalyst DC5 was placed in a fixed-bed reactor and reacted at a reaction pressure of 6.0MPa, a hydrogen-to-oil volume ratio of 500:1, and a liquid hourly space velocity of 10h⁻¹. -1 The reaction was carried out under hydrogen decondensation conditions at a reaction temperature of 340℃. The properties of the raw materials are shown in Table 2, and the product distribution and properties are shown in Table 8.

[0177] Table 8. Application results of catalysts prepared using ZE molecular sieves

[0178]

Claims

1. A ZSM-5 molecular sieve, characterized in that: The ZSM-5 molecular sieve has a total pyridine infrared spectral acidity of 0.03~0.40 mmol / g and a total di-tert-butylpyridine infrared spectral acidity of 0.002~0.02 mmol / g; the mesoporous pore volume of the ZSM-5 molecular sieve accounts for 10%~20% of the total pore volume, and in the ZSM-5 molecular sieve, the mesoporous pore volume of 2~10 nm accounts for 70%~95% of the total mesoporous pore volume.

2. The molecular sieve according to claim 1, wherein, The ZSM-5 molecular sieve has a total pyridine infrared spectral acid content of 0.10~0.20 mmol / g; a total di-tert-butylpyridine infrared spectral acid content of 0.005~0.01 mmol / g; and / or The ratio of the molar ratio of SiO2 / Al2O3 on the outer surface of the ZSM-5 molecular sieve to the total molar ratio of SiO2 / Al2O3 in the ZSM-5 molecular sieve is 2-100:

1.

3. The molecular sieve according to claim 2, wherein... The ratio of the molar ratio of SiO2 / Al2O3 on the outer surface of the ZSM-5 molecular sieve to the total molar ratio of SiO2 / Al2O3 in the ZSM-5 molecular sieve is 5-30:

1.

4. The molecular sieve according to claim 1 or 2, wherein, The outer surface SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 200~1000; and / or The total SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 30~100.

5. The molecular sieve according to claim 4, wherein, The outer surface SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 500~1000; and / or The total SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 40~70.

6. A method for preparing ZSM-5 molecular sieve according to any one of claims 1-5, characterized in that: The method includes the following steps: (1) Hydrothermal treatment of the raw material ZSM-5 molecular sieve; (2) Use a buffer solution to remove non-framework aluminum from the molecular sieve obtained in step (1); the buffer solution is one or more of oxalic acid-ammonium oxalate solution and acetic acid-ammonium acetate solution, with a pH range of 4.5~6.5; (3) Impregnate the material obtained in step (2) with a pore protection solution; the pore protection solution is one or more of isopropylamine solution, tetraethylammonium hydroxide solution, and tetrapropylammonium hydroxide solution. (4) The material obtained in step (3) is treated by adjusting the pH value to 6.5-7.5 with organic acid; (5) Mix the material obtained in step (4) with the dealuminizing and silicon replenishing reagent to perform dealuminizing and silicon replenishment; (6) The material obtained in step (5) is filtered, washed, dried and roasted.

7. The method according to claim 6, wherein, In step (1), The hydrothermal treatment temperature is 400~700℃; and / or The hydrothermal treatment time is 0.5~5 hours; and / or The pressure of the hydrothermal treatment is 0.05~0.5 MPa.

8. The method according to claim 7, wherein, In step (1), The temperature of the hydrothermal treatment is 500~600℃; The hydrothermal treatment time is 1-2 hours; and / or The pressure of the hydrothermal treatment is 0.1~0.3MPa.

9. The method according to claim 6, wherein, The buffer solution contains an acid with a molar concentration of 0.1–1.0 mol / L; and / or The liquid-to-solid volume ratio of the buffer solution to the molecular sieve obtained in step (1) is 3:1 to 10:

1.

10. The method according to claim 6 or 7, wherein, Step (2) includes the following process: Mix the molecular sieve obtained in step (1) with the buffer solution and stir, then separate the solid and liquid; and optionally repeat the above operation 2 to 4 times.

11. The method according to claim 10, wherein, Step (2) includes the following process: The processing temperature is 40~80℃, and the processing time is 0.5~3h.

12. The method according to claim 6 or 7, wherein, In step (3), The concentration of the pore protection fluid is 0.8~2.0 mol / L.

13. The method according to claim 6 or 7, wherein, In step (3), The impregnation is an equal-volume impregnation; and / or The impregnation treatment temperature is 20~25℃.

14. The method according to claim 6 or 7, wherein, In step (4), The organic acid is an organic acid with a molecular size between 0.55 nm and 2 nm that can be removed by calcination without damaging the molecular sieve structure.

15. The method according to claim 14, wherein, In step (4), The organic acid is one or more of the C7-C10 organic acids.

16. The method according to claim 15, wherein, In step (4), The organic acid is one or more of 2-methylbenzoic acid, 2-methylbenzenesulfonic acid, 2,4-dimethylbenzenesulfonic acid, 2,4-dimethylbenzoic acid, 1,2,5-trimethylbenzenesulfonic acid, and 1,2,5-trimethylbenzoic acid.

17. The method according to claim 16, wherein, In step (4), The organic acid is one or more of 2,4-dimethylbenzenesulfonic acid and 2,4-dimethylbenzoic acid.

18. The method according to claim 6 or 7, wherein, The process described in step (4) includes: first mixing the material obtained in step (3) with water.

19. The method according to claim 18, wherein, The liquid-to-solid volume ratio of water to the material obtained in step (3) is 2:1 to 6:

1.

20. The method according to claim 6 or 7, wherein, In step (5), The dealuminizing and silicon-replenishing agent contains one or more of the following: fluorosilicic acid, fluorosilicate, silicon halide, and silicate ester. and / or The molar concentration of the dealuminizing and silicon-replenishing reagent is 0.3~1.0 mol / L; and / or The mass ratio of the material obtained in step (4) to the dealuminizing and silicon-replenishing reagent is 1:1 to 1:5; and / or The mixing temperature is 60~100℃.

21. The method according to claim 20, wherein, In step (5), The dealuminizing and silicon-replenishing agent is composed of one or more of the following: ammonium hexafluorosilicate, fluorosilicic acid, sodium fluorosilicate, silicon tetrachloride, silicon tetrafluoride, and tetraethyl orthosilicate.

22. The method according to claim 21, wherein, In step (5), The dealuminizing and silicon-replenishing agent is at least one of ammonium hexafluorosilicate solution and tetraethyl orthosilicate solution.

23. The method according to claim 6 or 7, wherein, Step (5) includes heating the material obtained in step (4) to 60~100℃ and stirring continuously, adding aluminum removal and silicon replenishment reagent dropwise, and continuing to stir for 60~120 minutes after the addition is completed.

24. The use of the molecular sieve according to any one of claims 1-5 as a support and / or active component of a catalyst.

25. The application according to claim 24, wherein, The use of the molecular sieve according to any one of claims 1-5 as a hydrogenation catalyst support.

26. A hydrogenation catalyst, characterized in that, The hydrogenation catalyst contains the ZSM-5 molecular sieve as described in any one of claims 1-5 and the hydrogenation active component.

27. The catalyst according to claim 26, wherein, The hydrogenation active component is selected from one or more metals of Group VIB, VIIB, and VIII.

28. The catalyst according to claim 27, wherein, The hydrogenation active component is selected from one or more of Pt, Pd, Ni, W, Mo, and Co.

29. A hydrogen-induced dewaxing catalyst, characterized in that, The catalyst contains the ZSM-5 molecular sieve as described in any one of claims 1-5.

30. The catalyst according to claim 29, wherein, The hydrogen-induced condensation depressant catalyst comprises the ZSM-5 molecular sieve and a Group VIII metal component, wherein, based on the weight of the catalyst, the content of the ZSM-5 molecular sieve is 30% to 90%, and the content of the Group VIII metal component, calculated as oxides, is 5% to 40%.

31. The catalyst according to claim 29, wherein, The hydrogen-induced condensation depressant catalyst comprises the ZSM-5 molecular sieve, alumina, and a Group VIII metal component, wherein, based on the weight of the catalyst, 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 oxides, is 5% to 40%.

32. The application of the hydrodewaxing catalyst according to any one of claims 29-31 in hydrodewaxing of oil products.

33. The application according to claim 32, wherein, The oil product is a blend of straight-run diesel, catalytic diesel, and / or coking diesel.

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