Modified zsm-22 molecular sieve, method for preparing the same, and use thereof in isodewaxing

Abstract

The application discloses a modified ZSM-22 molecular sieve, wherein the molar ratio of SiO2 / Al2O3 of the outer surface of the modified ZSM-22 molecular sieve is 500-1000, the molar ratio of SiO2 / Al2O3 of the bulk phase is 40-120; the total pyridine infrared acid amount is 0.2-0.8 mmol / g, and the di-tert-butyl pyridine infrared total acid amount is 0.001-0.03 mmol / g. The preparation method of the modified ZSM-22 molecular sieve comprises the following steps: (1) preparing a ZSM-22 molecular sieve without removing a template agent; (2) mixing the ZSM-22 molecular sieve obtained in the step (1) with a de-alumination and silicon supplementing reagent to perform de-alumination and silicon supplementing; (3) performing high-temperature calcination and template agent removal treatment on the material obtained in the step (2); and (4) treating the material obtained in the step (3) with an aqueous aluminum salt solution, and then performing filtration, water washing and drying to obtain the modified ZSM-22 molecular sieve. The modified molecular sieve is used in a lubricating oil fraction isomerization dewaxing process, and has the characteristics of high lubricating oil base oil yield, high viscosity index and good low-temperature flow performance.

Description

TECHNICAL FIELD

[0001] The present application relates to a modified ZSM-22 molecular sieve, a preparation method thereof and an application thereof in isomerization dewaxing. BACKGROUND

[0002] Normal alkanes are non-ideal components in lubricating oil due to their high condensation points. In order to improve the low-temperature fluidity of lubricating oil, the normal alkanes therein are usually removed, which is commonly known as "dewaxing". The commonly used methods for dewaxing of lubricating oil mainly include solvent dewaxing, catalytic dewaxing and isomerization dewaxing.

[0003] Solvent dewaxing is a method in which the lubricating oil raw material is diluted and frozen by a solvent, so that the wax therein is crystallized and separated, thereby reducing the condensation point of the lubricating oil. This method not only wastes a large amount of organic solvent, but also has high operation cost and high energy consumption, and is harmful to human body and pollutes the environment. Catalytic dewaxing is a method in which a molecular sieve catalyst with shape-selective cracking function is used to selectively crack the wax in the lubricating oil fraction into small molecular hydrocarbons. This method reduces the yield and viscosity index of the lubricating oil base oil, and the by-products have low value, resulting in economic loss. Isomerization dewaxing is a method in which a molecular sieve catalyst with shape-selective isomerization function is used to cause the normal alkanes with high condensation points in the lubricating oil to isomerize in the molecular sieve channel, so that isomeric alkanes with low condensation points and high viscosity indexes are generated. The low-condensation-point naphthenes and isomeric alkanes are retained in the lubricating oil fraction, so that the purpose of selective dewaxing is achieved. The lubricating oil base oil obtained by isomerization dewaxing has high yield, high viscosity index and good low-temperature fluidity, and has attracted wide attention in recent years.

[0004] CN1488733A discloses an isomerization dewaxing method, which uses a new type of phosphorus-silicon-aluminum molecular sieve PAS-1 with AEL structure as the acid component of the dewaxing catalyst, and is used for isomerization dewaxing reaction of lubricating oil fraction, so that lubricating oil base oil with low condensation point and high viscosity index can be obtained. However, due to the high surface acidity of the molecular sieve, cracking and other side reactions occur during the isomerization dewaxing process, resulting in a low yield of the base oil.

[0005] US6204426 and CN105214717A etc. all propose to use two or more molecular sieves with shape-selective isomerization function as the carrier component to prepare an isomerization catalyst, which is used for isomerization dewaxing reaction of lubricating oil. However, due to the difference in acidity of different molecular sieves, the synergistic effect of the mixed molecular sieves cannot be effectively exerted, and the utilization efficiency of the molecular sieves is low.

[0006] In order to ensure high base oil yield and good low temperature fluidity in the process of lubricating oil isomerization dewaxing, the isomerization selectivity of the catalyst needs to be improved and the cracking reaction needs to be reduced as much as possible. The isomerization reaction of n-alkanes catalyzed by molecular sieve follows the pore mechanism and the lock-key mechanism, but due to the existence of some acid centers on the outer surface of the molecular sieve which do not have shape-selective isomerization catalytic properties, cracking and other side reactions are prone to occur, therefore, it is of great significance to modify the outer surface of the molecular sieve, reduce the acidity of the outer surface and retain the acidity in the pore, for improving the selectivity of the isomerization reaction. SUMMARY

[0007] In view of the deficiencies of the prior art, the application provides a modified ZSM-22 molecular sieve, a preparation method thereof and application thereof in isomerization dewaxing, the modified molecular sieve is used in the process of isomerization dewaxing of lubricating oil fraction, and has the characteristics of high lubricating oil base oil yield, high viscosity index and good low temperature fluidity.

[0008] The first aspect of the application provides a modified ZSM-22 molecular sieve, the molar ratio of SiO2 / Al2O3 of the outer surface of the modified ZSM-22 molecular sieve is 500-1000, the molar ratio of SiO2 / Al2O3 of the bulk phase is 40-120; the total pyridine infrared acid amount is 0.2-0.8 mmol / g, and the total di-tert-butyl pyridine infrared acid amount is 0.001-0.03 mmol / g.

[0009] Further, the molar ratio of SiO2 / Al2O3 of the outer surface of the modified ZSM-22 molecular sieve is 600-900, the molar ratio of SiO2 / Al2O3 of the bulk phase is 60-100; the total pyridine infrared acid amount is 0.3-0.6 mmol / g, and the total di-tert-butyl pyridine infrared acid amount is 0.01-0.025 mmol / g.

[0010] The second aspect of the application provides a preparation method of the modified ZSM-22 molecular sieve, comprising:

[0011] (1) preparing a ZSM-22 molecular sieve without removing the template agent;

[0012] (2) mixing the ZSM-22 molecular sieve obtained in step (1) with a de-alumination and silicon supplementation reagent to perform de-alumination and silicon supplementation;

[0013] (3) performing high-temperature calcination and template removal treatment on the material obtained in step (2);

[0014] (4) treating the material obtained in step (3) with an aqueous aluminum salt solution, then filtering, washing with water and drying to obtain the modified ZSM-22 molecular sieve.

[0015] Further, in step (1), the ZSM-22 molecular sieve without removing the template agent can be prepared by a hydrothermal synthesis method. For example, the silicon source, the aluminum source, the template agent, the alkali source, and water are added in the following molar ratio: SiO2:(0.006-0.03)Al2O3:(0.2-4.0)R (template agent):(0.01-10)K2O:(10-200)H2O. The mixture is crystallized at 150-180°C for 2-5 days, and then the product is washed to a pH value of 7-8, and then filtered, dried at 80-120°C, to obtain the ZSM-22 molecular sieve without removing the template agent.

[0016] Further, in the preparation of the ZSM-22 molecular sieve, the silicon source is selected from one or more of silica sol, white carbon black, tetraethyl orthosilicate, etc., the aluminum source is selected from one or more of aluminum sulfate octadecahydrate, aluminum isopropoxide, pseudo-boehmite, potassium meta-aluminate, etc., the template agent is selected from one or more of 1,6-hexanediamine, isopropylamine, n-butylamine, diethylamine, imidazole-based double quaternary ammonium salt, etc., the alkali source is potassium hydroxide, and the water is deionized water.

[0017] Further, in step (2), the de-alumination and silicon supplementing agent is at least one of ammonium hexafluorosilicate solution and tetraethyl orthosilicate solution.

[0018] Further, in step (2), the molar concentration of the de-alumination and silicon supplementing agent is 0.5-1.5 mol / L. The mass ratio of the ZSM-22 molecular sieve obtained in step (1) to the de-alumination and silicon supplementing agent is 1:2-1:10.

[0019] Further, in step (2), the specific operation process of de-alumination and silicon supplementing is as follows: the ZSM-22 molecular sieve obtained in step (1) is uniformly mixed with water, heated to 60-100°C, continuously stirred, and the de-alumination and silicon supplementing agent is added dropwise. After the addition is completed, the stirring is continued for 60-120 min, and then the product is filtered while hot, washed with water, filtered again, and dried. The liquid-solid volume ratio of water to the ZSM-22 molecular sieve obtained in step (1) is 2:1-10:1 mL / g.

[0020] Further, in step (3), the high-temperature calcination conditions are as follows: the temperature is 400-700°C, preferably 500-600°C, and the time is 1-12 h, preferably 4-6 h.

[0021] Further, in step (4), the aqueous aluminum salt solution is one or more of aluminum sulfate solution, aluminum chloride solution, and aluminum nitrate solution. The concentration (calculated as Al 3+ ) of the aluminum salt is 0.2-2.0 mol / L, preferably 0.5-1.5 mol / L, and the liquid-solid volume ratio of the aqueous aluminum salt solution to the material obtained in step (3) is 3:1-10:1 mL / g.

[0022] Further, in step (4), the specific treatment process is as follows: the material obtained in step (3) is mixed with an aqueous solution of aluminum salt and stirred, the treatment temperature is 40-90°C, the treatment time is 0.5-3h, then filtered, the filter cake is washed with water until the pH value of the washing liquid approaches neutral, and then dried at 80-120°C for 4-8h to obtain the modified ZSM-22 molecular sieve.

[0023] The third aspect of the present application provides a dewaxing catalyst, which comprises a hydrogenation active metal component and a carrier, and the carrier comprises the modified ZSM-22 molecular sieve and a macroporous alumina.

[0024] Further, the macroporous alumina has the following properties: a pore volume of 0.7-1.0mL / g, a specific surface area of 200-500m 2 / g.

[0025] Further, in the isomerization dewaxing catalyst, the content of the modified ZSM-22 molecular sieve is 20%-80% and the content of the macroporous alumina is 20%-80% based on the weight of the carrier.

[0026] Further, the isomerization dewaxing catalyst further comprises a binder, such as a small-pore alumina, and the content of the binder is 0.1%-2% based on the weight of the catalyst.

[0027] Further, the hydrogenation active metal is a Group VIII noble metal component, and the content of the Group VIII noble metal component is 0.01%-5% and preferably 0.5%-1.0% based on the weight of the catalyst.

[0028] Further, the specific surface area of the catalyst is 200-400m 2 / g, and the pore volume is 0.25-0.45mL / g.

[0029] The fourth aspect of the present application provides a preparation method of an isomerization dewaxing catalyst, which comprises the preparation of a carrier and the loading of a hydrogenation active metal component.

[0030] In the preparation process of the carrier, the modified ZSM-22 molecular sieve and the macroporous alumina are mixed, formed, and then dried and calcined to prepare the carrier.

[0031] Further, in the preparation process of the carrier, the drying and calcining can be carried out under conventional conditions, generally dried at 100°C-150°C for 1-12h, and then calcined at 450°C-550°C for 3.0-6.0h.

[0032] Further, the catalyst carrier is loaded with the hydrogenation active metal component by conventional methods, such as ion exchange method or impregnation method, etc. In the present application, the impregnation method is preferred to load the hydrogenation active metal component, and then drying and calcination to obtain the isomerization dewaxing catalyst. Namely, the catalyst carrier is impregnated with the solution of the water-soluble compound containing the Group VIII noble metal, the impregnated carrier is dried at 100-150 DEG C for 1-12 h, and then calcined at 500-600 DEG C for 3.0-6.0 h to prepare the final catalyst.

[0033] The fifth aspect of the present application provides an isomerization dewaxing method, which comprises the reaction of the raw oil under the action of the isomerization dewaxing catalyst, and the reaction conditions are as follows: the reaction pressure is 3.0-18.0 MPa, the temperature is 300-420 DEG C, the hydrogen / oil volume ratio is 500:1-2000:1, the liquid hourly space velocity is 0.5-5.0 h-1, and the reaction time is 0.5-5.0 h. -1 .

[0034] Compared with the prior art, the present application has the following advantages:

[0035] 1. In the method of the present application, the modified ZSM-22 molecular sieve used in the catalyst has low total acid amount of di-tert-butylpyridine, and the open and unblocked pore structure is obtained while the external acid sites are eliminated, the isomerization performance of the molecular sieve is strengthened, and the selectivity of the product is improved; the isomerization dewaxing catalyst of the present application is suitable for the isomerization dewaxing reaction of the lubricating oil, the yield reduction of the base oil caused by excessive cracking can be reduced, and the low-temperature flow performance of the lubricating oil base oil is effectively improved.

[0036] 2. In the method of the present application, the preparation method of the modified ZSM-22 molecular sieve, firstly, the molecular sieve obtained by hydrothermal synthesis is not subjected to the template removal treatment, the organic template molecules in the pore act as the pore protectant, the external acid centers of the molecular sieve are removed by the method of dealumination and silicon supplementation, and the excessive cracking reaction of the n-alkanes on the external surface of the molecular sieve is reduced. The aluminum on the external surface of the molecular sieve is replaced by the silicon atoms which do not have the acid property under the action of the dealumination and silicon supplementation reagent, and the integrity of the pore structure and the acid centers in the pore are effectively protected due to the presence of the template molecules; then, the template molecules in the pore are removed by high-temperature calcination, and the non-framework aluminum generated in the modification process is removed by the aqueous aluminum salt solution, so that the pore of the molecular sieve is more open and unblocked. DETAILED DESCRIPTION

[0037] The role and effect of the technical scheme of the present application will be further illustrated by the following examples and comparative examples, but the following examples do not constitute the limitation on the protection scope of the present application.

[0038] In the present application, the mass fraction is involved in the examples and comparative examples without special instructions.

[0039] In the present application, the molar ratio of the outer surface SiO2 / Al2O3 is measured by X-ray photoelectron spectroscopy (XPS). The Multilab2000 electron spectrometer of Thermofisher Company is used to determine the element composition and state of the catalyst surface. The excitation source is Mg Kα, and the cathode voltage and current are 13 kV and 20 mA, respectively. The electron binding energy is calibrated by C1s (284.6 eV).

[0040] In the present application, the molar ratio of the bulk SiO2 / Al2O3 is obtained by X-ray fluorescence spectroscopy (XRF). The ZSX100e X-ray fluorescence spectrometer is used, the spectrum is Kα, the crystal is Li F1, the target material is Rh, the detector is SC scintillation, the timing is 20 s, and the light path atmosphere is vacuum.

[0041] In the present application, the pyridine infrared determination method is as follows: the powdered ZSM-22 molecular sieve is pressed into a tablet, vacuumed, and then degassed at 450℃ for 2h. When the temperature drops to room temperature, the pyridine molecule is used as a probe molecule to determine the infrared spectrum of chemical desorption, and the adsorption amount is calculated.

[0042] In the present application, the total acid amount of the di-tert-butyl pyridine refers to the protonic acid that can be contacted by the 2,6-di-tert-butyl pyridine molecule with a kinetic diameter of 10.5Å. The 2,6-di-tert-butyl pyridine infrared determination method is as follows: the powdered ZSM-22 molecular sieve is pressed into a tablet, vacuumed, and then degassed at 450℃ for 2h. When the temperature drops to room temperature, the 2,6-di-tert-butyl pyridine molecule is used as a probe molecule to determine the infrared spectrum of chemical desorption, and the adsorption amount is calculated.

[0043] Example 1

[0044] A mixture gel with molar composition of SiO2: 0.013Al2O3: 0.3DAH: 0.15K2O: 60H2O was prepared by dissolving 84.0 g of potassium hydroxide in 4950 mL of water, and then adding 43.3 g of aluminum sulfate octadecahydrate, 750.0 g of silica sol (40% by mass), and 174.0 g of 1,6-hexanediamine (DAH) in sequence under stirring. The initial mixed gel was loaded into a sealed autoclave and crystallized at 160°C for 3 days. The product was washed to pH 7, filtered, and dried at 120°C to obtain ZSM-22 powder without removal of the template. 120 g of the ZSM-22 powder was mixed with 720 mL of water, heated to 60°C, and then 360 mL of 0.5 mol / L ammonium hexafluorosilicate solution was added at a constant rate using a peristaltic pump. The temperature was maintained at 60°C and stirring was continued for 90 min. The hot filtrate was filtered, 960 mL of water was added to the filter cake, which was heated to 60°C and maintained for 20 min, and then filtered while hot. The filter cake was dried at 120°C for 8 h, and then the dried product was calcined at 500°C for 4 h to remove the template. The calcined product was placed in 1000 mL of 0.5 mol / L aluminum sulfate solution, stirred, and heated to 60°C for 90 min. The hot filtrate was filtered, and the filter cake was washed with deionized water until the pH of the washing solution was close to 7. The filter cake was dried at 120°C for 8 h to obtain a modified molecular sieve, which was named ZSM-22-1.

[0045] Example 2

[0046] ZSM-22 powder without removal of the template was prepared as in Example 1. 120 g of the ZSM-22 powder was mixed with 720 mL of water, heated to 60°C, and then 360 mL of 0.8 mol / L tetraethyl orthosilicate solution was added at a constant rate using a peristaltic pump. The temperature was maintained at 60°C and stirring was continued for 90 min. The hot filtrate was filtered, 960 mL of water was added to the filter cake, which was heated to 60°C and maintained for 20 min, and then filtered while hot. The filter cake was dried at 120°C for 8 h, and then the dried product was calcined at 550°C for 5 h to remove the template. The calcined product was placed in 1000 mL of 0.8 mol / L aluminum nitrate solution, stirred, and heated to 70°C for 60 min. The hot filtrate was filtered, and the filter cake was washed with deionized water until the pH of the washing solution was close to 7. The filter cake was dried at 120°C for 8 h to obtain a modified molecular sieve, which was named ZSM-22-2.

[0047] Example 3

[0048] The ZSM-22 powder without removing the template agent was prepared as in Example 1. 120 g of the ZSM-22 powder was mixed with 720 mL of water, heated to 60°C and stirred. 360 mL of 1.0 mol / L ammonium hexafluorosilicate solution was added dropwise at a constant rate using a peristaltic pump. The temperature was maintained at 60°C and stirring was continued for 90 min. The hot filtrate was filtered. 960 mL of water was added to the filter cake, heated to 60°C and maintained for 20 min. The hot filtrate was filtered. The filter cake was dried at 120°C for 8 h. The dried product was placed in a muffle furnace and calcined at 550°C for 6 h to remove the template agent. The obtained material was placed in 1000 mL of 0.8 mol / L aluminum chloride solution. The solution was stirred and heated to 70°C. After 120 min, the hot filtrate was filtered. The filter cake was washed with deionized water until the pH of the washing solution was close to 7. The filter cake was dried at 120°C for 8 h. The modified molecular sieve was named ZSM-22-3.

[0049] Example 4

[0050] The ZSM-22 powder without removing the template agent was prepared as in Example 1. 120 g of the ZSM-22 powder was mixed with 720 mL of water, heated to 60°C and stirred. 360 mL of 1.0 mol / L ammonium hexafluorosilicate solution was added dropwise at a constant rate using a peristaltic pump. The temperature was maintained at 60°C and stirring was continued for 90 min. The hot filtrate was filtered. 960 mL of water was added to the filter cake, heated to 60°C and maintained for 20 min. The hot filtrate was filtered. The filter cake was dried at 120°C for 8 h. The dried product was placed in a muffle furnace and calcined at 550°C for 6 h to remove the template agent. The obtained material was placed in 1000 mL of 0.8 mol / L aluminum chloride solution. The solution was stirred and heated to 70°C. After 120 min, the hot filtrate was filtered. The filter cake was washed with deionized water until the pH of the washing solution was close to 7. The filter cake was dried at 120°C for 8 h. The modified molecular sieve was named ZSM-22-3.

[0051] Example 5

[0052] The ZSM-22 powder without removing the template agent was prepared as in Example 1. 120 g of the ZSM-22 powder was mixed with 720 mL of water, heated to 60°C, and stirred. 360 mL of 1.2 mol / L ammonium hexafluorosilicate solution was added dropwise at a constant rate using a peristaltic pump, and the temperature was maintained at 60°C and stirring was continued for 90 min. The hot filtrate was filtered, 960 mL of water was added to the filter cake, which was heated to 60°C and maintained for 20 min, and then filtered hot. The filter cake was dried at 120°C for 8 h, and then the dried product was placed in a muffle furnace and calcined at 500°C for 6 h to remove the template agent. The resulting material was placed in 1000 mL of 1.5 mol / L aluminum chloride solution, stirred, and heated to 80°C, and maintained for 120 min. The hot filtrate was filtered, and the filter cake was washed with deionized water until the pH of the washing liquid was close to 7. The filter cake was dried at 120°C for 8 h, and the modified molecular sieve obtained was named ZSM-22-5.

[0053] Example 6

[0054] The ZSM-22 powder without removing the template agent was prepared as in Example 1. 120 g of the ZSM-22 powder was mixed with 720 mL of water, heated to 60°C, and stirred. 360 mL of 1.2 mol / L ammonium hexafluorosilicate solution was added dropwise at a constant rate using a peristaltic pump, and the temperature was maintained at 60°C and stirring was continued for 90 min. The hot filtrate was filtered, 960 mL of water was added to the filter cake, which was heated to 60°C and maintained for 20 min, and then filtered hot. The filter cake was dried at 120°C for 8 h, and then the dried product was placed in a muffle furnace and calcined at 600°C for 6 h to remove the template agent. The resulting material was placed in 1000 mL of 1.2 mol / L aluminum nitrate solution, stirred, and heated to 70°C, and maintained for 60 min. The hot filtrate was filtered, and the filter cake was washed with deionized water until the pH of the washing liquid was close to 7. The filter cake was dried at 120°C for 8 h, and the modified molecular sieve obtained was named ZSM-22-6.

[0055] Comparative Example 1

[0056] Similar to Example 1, ZSM-22 powder without template removal was prepared, and then calcined at 550℃ for 6 hours to obtain ZSM-22 powder with template removal. 120g of the above ZSM-22 powder was taken, added to 720mL of water and mixed evenly. The mixture was stirred and heated to 60℃. 360mL of 1.2mol / L ammonium hexafluorosilicate solution was added dropwise using a peristaltic pump, maintaining the temperature at 60℃ and stirring continuously for 90min. The mixture was filtered while hot, and 960mL of water was added to the resulting filter cake. The mixture was heated to 60℃ and maintained for 20min, then filtered while hot. The filter cake was dried at 120℃ for 8 hours. The resulting material was placed in 1000mL of 0.8mol / L aluminum sulfate solution, stirred, and heated to 70℃. After maintaining the temperature for 90min, the mixture was filtered while hot, and the filter cake was washed with deionized water. Washing was stopped when the pH of the washing solution approached 7. The resulting filter cake was dried at 120℃ for 8 hours. The modified molecular sieve was named ZSM-22-D1.

[0057] Comparative Example 2

[0058] Similar to Example 1, ZSM-22 powder without template removal was prepared, and then calcined at 600℃ for 5 h to obtain ZSM-22 powder with template removal. 120 g of the above ZSM-22 powder was placed in 1000 mL of 1.0 mol / L aluminum nitrate solution, stirred and heated to 80℃, maintained for 60 min, and then filtered while hot. The filter cake was washed with deionized water, and washing was stopped when the pH of the washing solution was close to 7. The obtained filter cake was dried at 120℃ for 8 h, and the modified molecular sieve was named ZSM-22-D2.

[0059] Table 1. Characterization results of the modified molecular sieves obtained in the examples and comparative examples.

[0060]

[0061] Example 7

[0062] 41.2g of modified molecular sieve ZSM-22-3 (97wt% dry basis) and 85.7g of macroporous alumina (pore volume 1.0ml / g, specific surface area 400m²) were added. 2 (70wt% dry basis) was mixed in a roller mill, and a thin binder (small pore alumina concentration 2.2 g / 100mL) was added. The mixture was rolled into a paste, extruded into strips, and dried at 120℃ for 6 h. Then, it was calcined at 550℃ for 4 h to obtain a support. The support was impregnated with H2PtCl6 solution at room temperature for 2 h, dried at 120℃ for 6 h, and calcined at 550℃ for 4 h to obtain catalyst CAT-1. The properties of the catalyst are shown in Table 2.

[0063] Example 8

[0064] Put 51.5 g of modified molecular sieve ZSM-22-4 (dry basis 97 wt%), 71.4 g of large-pore alumina (pore volume 1.0 ml / g, specific surface area 400 m 2 / g, dry basis 70 wt%) into a roller mill and mix, add dilute binder (small-pore alumina concentration 2.2 g / 100 ml), roll into paste, extrude into strips, dry the extruded strips at 120°C for 6 h, then calcine at 550°C for 4 h to obtain the carrier, impregnate the carrier with H2PdCl4 solution at room temperature for 2 h, dry at 120°C for 6 h, and calcine at 550°C for 4 h with temperature programming to obtain the catalyst CAT-2. The properties of the catalyst are shown in Table 2.

[0065] Example 9

[0066] Put 61.9 g of modified molecular sieve ZSM-22-5 (dry basis 97 wt%), 57.1 g of large-pore alumina (pore volume 1.0 ml / g, specific surface area 400 m 2 / g, dry basis 70 wt%) into a roller mill and mix, add dilute binder (small-pore alumina concentration 2.2 g / 100 ml), roll into paste, extrude into strips, dry the extruded strips at 120°C for 6 h, then calcine at 550°C for 4 h to obtain the carrier, impregnate the carrier with H2PtCl6 solution at room temperature for 2 h, dry at 120°C for 6 h, and calcine at 500°C for 4 h with temperature programming to obtain the catalyst CAT-3. The properties of the catalyst are shown in Table 2.

[0067] Comparative Example 3

[0068] Put 51.5 g of modified molecular sieve ZSM-22-D1 (dry basis 97 wt%), 71.4 g of large-pore alumina (pore volume 1.0 ml / g, specific surface area 400 m 2 / g, dry basis 70 wt%) into a roller mill and mix, add dilute binder (small-pore alumina concentration 2.2 g / 100 ml), roll into paste, extrude into strips, dry the extruded strips at 120°C for 6 h, then calcine at 550°C for 4 h to obtain the carrier, impregnate the carrier with H2PtCl6 solution at room temperature for 2 h, dry at 120°C for 6 h, and calcine at 500°C for 4 h with temperature programming to obtain the catalyst CAT-D1. The properties of the catalyst are shown in Table 2.

[0069] Comparative Example 4

[0070] Put 61.9 g of modified molecular sieve ZSM-22-D2 (dry basis 97 wt%), 57.1 g of large-pore alumina (pore volume 1.0 ml / g, specific surface area 400 m 2The catalyst CAT-D2 was prepared by the following steps: 70wt% of the catalyst precursor (dry basis) was mixed and milled in a roller mill, and then 2.2g / 100mL of a dilute binder (small-pore alumina) was added to the mixture, which was then rolled into a paste, extruded into a strip, dried at 120°C for 6h, and then calcined at 550°C for 4h to obtain a carrier. The carrier was then impregnated with an H2PdCl4 solution at room temperature for 2h, dried at 120°C for 6h, and then calcined at 500°C for 4h by temperature programming to obtain the catalyst CAT-D2. The properties of the catalyst are shown in Table 2.

[0071] Table 2 Catalyst composition and physicochemical properties

[0072]

[0073] Example 10

[0074] This example describes the evaluation method and results of the method of the present application. Before feeding, the catalyst was pre-reduced, and the noble metal on the catalyst was converted into a reduced state by reduction at 500°C for 6h in a hydrogen atmosphere. Subsequently, the catalysts CAT-1, CAT-2, CAT-3, CAT-D1 and CAT-D2 were evaluated in a fixed-bed hydrogenation test device under the same process conditions. The evaluation conditions were as follows: hydrogen / oil volume ratio was 1000:1, reaction pressure was 12.0MPa, reaction liquid hourly space velocity was 1.0h -1 The properties of the raw material oil used in the evaluation are shown in Table 3, and the evaluation results are shown in Table 4.

[0075] As can be seen from the evaluation results, the method of the present application has the advantages of higher yield of the base oil, higher viscosity index, and better low-temperature flow performance when preparing a lubricating oil base oil.

[0076] Table 3 Properties of raw material oil

[0077]

[0078] Table 4 Comparison of evaluation results of catalyst performance of examples and comparative examples

[0079]

Claims

1. A modified ZSM-22 molecular sieve characterized by: The modified ZSM-22 molecular sieve has an external surface SiO2 / Al2O3 molar ratio of 500-1000 and a bulk SiO2 / Al2O3 molar ratio of 40-120; the pyridine infrared total acid amount is 0.2-0.8 mmol / g, and the di-tert-butyl pyridine infrared total acid amount is 0.001-0.03 mmol / g.

2. The molecular sieve of claim 1, characterized by: The modified ZSM-22 molecular sieve has an external surface SiO2 / Al2O3 molar ratio of 600-900 and a bulk SiO2 / Al2O3 molar ratio of 60-100; the pyridine infrared total acid amount is 0.3-0.6 mmol / g, and the di-tert-butyl pyridine infrared total acid amount is 0.01-0.025 mmol / g.

3. The method of making the ZSM-22 molecular sieve of claim 1 or 2, characterized by: It comprises: (1) preparing a ZSM-22 molecular sieve without removing a template agent; (2) mixing the ZSM-22 molecular sieve obtained in step (1) with a dealumination and silicon supplementation reagent to perform dealumination and silicon supplementation; (3) performing high-temperature calcination and template agent removal treatment on the material obtained in step (2); (4) treating the material obtained in step (3) with an aqueous aluminum salt solution, then filtering, washing with water and drying to obtain a modified ZSM-22 molecular sieve; The dealumination and silicon supplementation reagent is at least one of an ammonium hexafluorosilicate solution and a tetraethyl orthosilicate solution.

4. The method of claim 3, wherein: In step (1), the ZSM-22 molecular sieve without removing a template agent is prepared by a hydrothermal synthesis method.

5. The method of claim 4, wherein: The silicon source, aluminum source, template agent, alkali source and water are added in the following molar ratios: SiO2:(0.006-0.03)Al2O3:(0.2-4.0)R (template agent):(0.01-10)K2O:(10-200)H2O, the mixed material is crystallized at 150-180 ℃ for 2-5 days, the product is washed to a pH value of 7-8, then filtered, dried at 80-120 ℃, and the ZSM-22 molecular sieve without removing a template agent is obtained.

6. The method of claim 5, wherein: The silicon source is selected from one or more of silica sol, white carbon black and tetraethyl orthosilicate, the aluminum source is selected from one or more of aluminum sulfate octadecahydrate, aluminum isopropoxide, pseudo-boehmite and potassium meta-aluminate, the template agent is selected from one or more of 1,6-hexanediamine, isopropylamine, n-butylamine and imidazole-based double quaternary ammonium salt, the alkali source is potassium hydroxide, and the water is deionized water.

7. The method of claim 3, wherein: In step (2), the molar concentration of the dealumination and silicon supplementation reagent is 0.5-1.5 mol / L; and the mass ratio of the ZSM-22 molecular sieve obtained in step (1) to the dealumination and silicon supplementation reagent is 1:2-1:

10.

8. The method of claim 3, wherein: In step (2), the specific operation process of dealumination and silicon supplementation is as follows: the ZSM-22 molecular sieve obtained in step (1) is uniformly mixed with water, heated to 60-100 ℃ and continuously stirred, the dealumination and silicon supplementation reagent is added dropwise, continuous stirring is performed for 60-120 min after the dropwise addition is completed, the mixture is filtered while hot, the filter cake is washed with water, filtered again and dried; and the liquid-solid volume ratio of water to the ZSM-22 molecular sieve obtained in step (1) is 2:1-10:1 mL / g.

9. The method of claim 3, wherein: In step (3), the high-temperature calcination conditions are as follows: the temperature is 400-700 ℃, and the time is 1-12 h.

10. The method of claim 9, wherein: In step (3), the high-temperature calcination is performed at a temperature of 500-600 DEG C for 4-6 hours.

11. The method of claim 3, wherein: In step (4), the aqueous aluminum salt solution is one or more of aluminum sulfate solution, aluminum chloride solution and aluminum nitrate solution; the concentration of the aluminum salt is 0.2-2.0 mol / L, and the liquid-solid volume ratio of the aqueous aluminum salt solution to the material obtained in step (3) is 3:1-10:1 mL / g. 3+ In step (4), the aqueous aluminum salt solution is one or more of aluminum sulfate solution, aluminum chloride solution and aluminum nitrate solution; the concentration of the aluminum salt is 0.2-2.0 mol / L, and the liquid-solid volume ratio of the aqueous aluminum salt solution to the material obtained in step (3) is 3:1-10:1 mL / g.

12. The method of claim 11, wherein: In step (4), the concentration of the aluminum salt is 0.5 to 1.5 mol / L in terms of Al 3+ .

13. The method of claim 3, wherein: In step (4), the specific treatment process is as follows: the material obtained in step (3) is mixed with an aqueous solution of an aluminum salt and stirred at a temperature of 40-90 DEG C for 0.5-3 hours, then filtered, the filter cake is washed with water until the washing liquid reaches a neutral pH, and then dried at 80-120 DEG C for 4-8 hours to obtain the modified ZSM-22 molecular sieve.

14. A dewaxing catalyst characterized by: The dewaxing catalyst comprises a hydrogenation active metal component and a carrier, and the carrier comprises the modified ZSM-22 molecular sieve according to any one of claims 1-2 and macroporous alumina.

15. The catalyst of claim 14, wherein: The properties of the large-pore alumina are as follows: pore volume of 0.7 to 1.0 mL / g, specific surface area of 200 to 500 m 2 / g.

16. The catalyst of claim 14, wherein: The content of the modified ZSM-22 molecular sieve is 20-80% by weight of the carrier, and the content of the macroporous alumina is 20-80% by weight of the carrier.

17. The catalyst of claim 14, wherein: The hydrogenation active metal is a Group VIII noble metal component, and the content of the Group VIII noble metal component is 0.01-5% by weight of the catalyst.

18. The catalyst of claim 17, wherein: The content of the Group VIII noble metal component is 0.5-1.0% by weight of the catalyst.

19. The catalyst of claim 14, wherein: The specific surface area of the catalyst is 200 to 400 m 2 / g, and the pore volume is 0.25 to 0.45 mL / g.

20. A process for the preparation of the catalyst of any one of claims 14 to 19, characterized by: The preparation of the carrier and the loading of the hydrogenation active metal component are included; wherein the preparation of the carrier is as follows: the modified ZSM-22 molecular sieve and the macroporous alumina are mixed, formed, and then dried and calcined to prepare the carrier.

21. The method of claim 20, wherein: In the preparation process of the carrier, drying is performed at 100-150 DEG C for 1-12 hours, and then calcination is performed at 450-550 DEG C for 3.0-6.0 hours.

22. An isodewaxmg process characterized by: The method comprises subjecting raw oil to reaction in the presence of an isomerization dewaxing catalyst under the following reaction conditions: a reaction pressure of 3.0-18.0 MPa, a temperature of 300-420 ℃, a hydrogen / oil volume ratio of 500:1-2000:1, and a liquid hourly space velocity of 0.5-5.0 h-1. 1 The isomerization catalyst contains the modified ZSM-22 molecular sieve according to claim 1 or 2.

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