A method for producing a lubricating oil base oil by isomerization dewaxing

Abstract

The application discloses a method for producing lubricating oil base oil through isomerization dewaxing. The method comprises the following steps: mixing raw oil with hydrogen and then feeding the mixture into an isomerization dewaxing reaction zone for reaction, wherein the isomerization dewaxing reaction zone is filled with at least one isomerization dewaxing catalyst, which is marked as isomerization dewaxing catalyst II. The isomerization dewaxing catalyst II has the following properties: 7-26 nm mesopores account for 55-87% of the total pore volume, the amount of medium-strong B acid accounts for 5-18% of the total acid amount, and the ratio of medium-strong B acid to medium-strong L acid is 0.3-1.8. Preferably, 7-26 nm mesopores account for 65-80% of the total pore volume, the amount of medium-strong B acid accounts for 7-15% of the total acid amount, and the ratio of medium-strong B acid to medium-strong L acid is 0.4-1.6. The method has the advantages of high yield of target product, small loss of viscosity index, good product quality and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to a production method of lubricating oil base oil, in particular to a method for producing lubricating oil base oil by hydroisomerization dewaxing. BACKGROUND

[0002] The core of the production technology of lubricating oil base oil by hydrogenation method is isomerization dewaxing technology, which mainly generates low condensation point few branched chain isomerized alkanes from high condensation point long chain alkanes non-ideal components in the raw material through isomerization reaction, and the generated isomerized alkanes are retained in the base oil fraction, so as to achieve the purpose of reducing the pour point while ensuring the low loss of viscosity index. The core reaction of isomerization dewaxing technology is long chain alkane isomerization reaction, which mainly includes two steps of hydrogenation dehydrogenation and skeletal isomerization. Therefore, the reaction needs the participation of bifunctional catalyst, and the bifunctional isomerization catalyst suitable for long chain alkane isomerization reaction generally consists of metal active component and acidic carrier. The hydrogenation dehydrogenation reaction occurs on the active site of the metal component, and the skeletal isomerization reaction mainly occurs on the active site of the acidic carrier. The metal component in the catalyst usually uses noble metal Pt as the hydrogenation dehydrogenation active center, and the acidic carrier mainly uses molecular sieve with suitable pore structure and acid property. By using suitable molecular sieve acid component, the yield of the target product and the liquid yield in the production of lubricating oil base oil by isomerization dewaxing are improved, and the viscosity index loss is reduced on the basis of meeting the pour point requirement.

[0003] At present, the acid component of the isomerization dewaxing catalyst used in the isomerization dewaxing technology is mainly molecular sieve with one-dimensional straight pore, such as AEL type molecular sieve, MTT type molecular sieve, TON type molecular sieve, *MRE type molecular sieve and the like used in US6294081B1, US11220435B1, US9677016B2, US8475648B2, US10640389B2. According to the related literature reports, the above molecular sieves can be used as the acid component of the isomerization dewaxing catalyst to make the selective isomerization reaction of n-alkanes and reduce the pour point of the reaction raw oil. Among them, the *MRE skeletal molecular sieve is mainly ZSM-48 molecular sieve, and the other molecular sieves include COK-8, EU-2, EU-11, IZM-1, SSZ-91, ZBM-30 and the like.

[0004] US patent US10640389B uses hexamethonium hydroxide as a template agent, and adds FAU type molecular sieve to synthesize aluminum-rich *MRE molecular sieve, and applies it to the field of isomerization dewaxing, which has high catalytic activity. Chinese patent CN103803576A adds ZSM-48 crystal seeds and uses 12-crown ether-4 as a template agent to synthesize low-silicon aluminum ratio ZSM-48 molecular sieve, which has significantly improved acid amount compared with conventional molecular sieve, but the use of crown ether as a template agent during molecular sieve synthesis is expensive, which significantly increases the production cost.

[0005] Although the molecular sieve used in isomerization dewaxing to produce base oil has high acid amount, which can improve the conversion rate of catalytic isomerization of n-alkanes, the matching degree of different types of acid is low, which can increase the reaction opportunity of cracking and other side reactions, and the small pore size of the molecular sieve is not conducive to the desorption of product molecules, thereby reducing the yield of the target product and the quality of the product is not ideal. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a method for producing lubricating oil base oil by isomerization dewaxing, which has the advantages of high yield of target product, small loss of viscosity index, good product quality, etc.

[0007] A method for producing lubricating oil base oil by isomerization dewaxing, the method comprising mixing raw oil with hydrogen and then entering an isomerization dewaxing reaction zone for reaction, the isomerization dewaxing reaction zone being loaded with at least one isomerization dewaxing catalyst, denoted as isomerization dewaxing catalyst II, the isomerization dewaxing catalyst II having the following properties: 7-26 nm mesopores accounting for 55-87% of the total pore volume, medium-strong B acid accounting for 5-18% of the total acid, and the ratio of medium-strong B acid to medium-strong L acid being 0.3-1.8; preferably, 7-26 nm mesopores accounting for 65-80% of the total pore volume, medium-strong B acid accounting for 7-15% of the total acid, and the ratio of medium-strong B acid to medium-strong L acid being 0.4-1.6.

[0008] Further, in the method of the present application, the isomerization dewaxing catalyst II contains HZSM-48 molecular sieve, the HZSM-48 molecular sieve having 7-26 nm mesopores accounting for 35-80% of the total pore volume, medium-strong B acid accounting for 8-30% of the total acid, and the ratio of medium-strong B acid to medium-strong L acid being 0.7-4.5; preferably, 7-26 nm mesopores accounting for 40-75% of the total pore volume, medium-strong B acid accounting for 10-25% of the total acid, and the ratio of medium-strong B acid to medium-strong L acid being 0.8-4.0.

[0009] Further, in the method of the present application, the feed oil is any suitable feed oil known in the art, such as hydrocracking tail oil, hydroprocessing vacuum gas oil, hydroprocessing deasphalted oil, and the like. The feed oil needs to be treated to control the sulfur and nitrogen content before entering the isodewaxing reaction zone, and the sulfur content of the feed oil is less than 35 mg / g, preferably less than 15 mg / g, and the nitrogen content of the feed oil is less than 10 mg / g, preferably less than 2 mg / g.

[0010] Further, in the method of the present application, the isodewaxing catalyst II has a BET surface area of 140 m 2 / g to 450 m 2 / g, preferably a BET surface area of 150 m 2 / g to 330 m 2 / g; and a pore volume of 0.25 mL / g to 0.70 mL / g, preferably a pore volume of 0.30 mL / g to 0.65 mL / g.

[0011] Further, in the method of the present application, the isodewaxing catalyst II comprises a ZSM-48 molecular sieve and an active metal component. The active metal component is at least one of the Group VIII noble metals Pt and Pd, preferably Pt.

[0012] Further, in the method of the present application, the isodewaxing catalyst II further comprises an inorganic refractory oxide. The inorganic refractory oxide is one or more selected from the group consisting of alumina, titania, silica, boria, magnesia, zirconia, and clay, preferably alumina and / or silica, and more preferably alumina. The precursor of the inorganic refractory oxide can be one or more selected from the group consisting of boehmite, pseudoboehmite, diaspore, gibbsite, and bauxite, and preferably pseudoboehmite.

[0013] Further, in the method of the present application, the isodewaxing catalyst II has a molecular sieve content of 10 wt% to 90 wt%, preferably 20 wt% to 70 wt%, based on the weight of the final catalyst; an active metal content of 0.05 wt% to 5 wt% in terms of metal, preferably 0.1 wt% to 1.0 wt%; and an inorganic refractory oxide content of 5 wt% to 85 wt%, preferably 30 wt% to 70 wt%.

[0014] Further, in the method of the present application, after the feed oil is mixed with hydrogen and passes through the isodewaxing reaction zone, the mixture enters a hydrofining reaction zone for reaction. The operating conditions of the hydrofining reaction zone are the process conditions well known to those skilled in the art, for example, the reaction temperature is 200°C to 300°C, the reaction pressure is 6.0 MPa to 19.0 MPa, the volume space velocity is 0.5 h -1 ~ 2.8 h -1 , and the hydrogen to oil volume ratio is 400:1 to 1500:1.

[0015] Further, in the method of the present application, the hydrofining reaction zone is loaded with a hydrofining catalyst, which can be selected from the commonly used hydrofining catalysts, and can be a commercial hydrofining catalyst or prepared according to the general method in the art. The hydrofining catalyst carrier is generally Al2O3 or Al2O3-SiO2, and the active metal is one or both of Pt and Pd, and the weight content of the active metal in the catalyst is generally 0.05wt% to 1.0wt%. The catalyst needs to be reduced before use to ensure that the hydrogenation active metal is in a reduced state during the reaction.

[0016] Further, in the method of the present application, the isodewaxing reaction zone comprises a first catalyst bed and a second catalyst bed, and the first catalyst bed is loaded with a conventional isodewaxing catalyst, which is referred to as isodewaxing catalyst I, and the second catalyst bed is loaded with isodewaxing catalyst II; compared with the isodewaxing catalyst I, the isodewaxing catalyst II has an increased 7-28nm mesopore content, a decreased medium-strong B acid content, and a decreased medium-strong B acid / medium-strong L acid ratio.

[0017] Further, in the method of the present application, compared with the isodewaxing catalyst I, the isodewaxing catalyst II has an increased 7-26nm mesopore content by 5-57 percentage points, a decreased medium-strong B acid content by 3-16 percentage points, and a decreased medium-strong B acid / medium-strong L acid ratio by 0.2-2.2; preferably, the 7-26nm mesopore content is increased by 10-50 percentage points, the medium-strong B acid content is decreased by 4-13 percentage points, and the medium-strong B acid / medium-strong L acid ratio is decreased by 0.3-1.8.

[0018] Further, in the method of the present application, the volume ratio of the isodewaxing catalyst II to the isodewaxing catalyst I is 1:9 to 4:1, and preferably 1:4 to 7:3.

[0019] Further, in the method of the present application, the isodewaxing catalyst I comprises a conventional *MRE type molecular sieve and an active metal component. The active metal component is at least one of the Group VIII noble metals Pt and Pd, and is preferably Pt; and the conventional *MRE type molecular sieve is one or more of ZSM-48, COK-8, EU-2, EU-11, IZM-1, SSZ-91, and ZBM-30, and is preferably ZSM-48 molecular sieve.

[0020] Further, in the method of the present application, the isodewaxing catalyst I further comprises an inorganic refractory oxide, the inorganic refractory oxide is one or more selected from alumina, titania, silica, boria, magnesia, zirconia and clay, preferably alumina and / or silica, more preferably alumina; the precursor of the inorganic refractory oxide can be one or more selected from boehmite, pseudoboehmite, gibbsite, bayerite and bauxite, preferably pseudoboehmite.

[0021] Further, in the method of the present application, the isodewaxing catalyst I, the content of the MRE type molecular sieve is 25wt% to 80wt%, preferably 40wt% to 70wt% based on the weight of the final catalyst; the content of the active metal is 0.05wt% to 5wt% based on the metal, preferably 0.1wt% to 1.0wt%; the content of the inorganic refractory oxide is 15wt% to 70wt%, preferably 30wt% to 60wt%.

[0022] Further, in the method of the present application, the reaction conditions of the isodewaxing reaction zone are the process conditions well known to the skilled person, for example, the reaction temperature is generally 250℃ to 400℃, the reaction pressure is generally 2MPa to 20MPa, the volume space velocity is generally 0.5h -1 ~4.0h -1 , and the volume ratio of hydrogen to oil is generally 500:1 to 1400:1.

[0023] According to the characteristics of producing lubricating oil base oil by isodewaxing, the present application improves the overall reaction performance of the isodewaxing device by grading the isodewaxing catalysts with different mesopore distributions and acid types. The larger mesopore diameter in the isodewaxing catalyst is conducive to the rapid desorption of reaction products, reducing the opportunity of secondary isomerization reaction, thereby increasing the content of single branched-chain alkane isomers. With the flow direction of the reaction raw material and hydrogen, the amount of larger mesopores in the graded isodewaxing catalyst increases, while the proportion of medium-strong B acid and the proportion of medium-strong B / medium-strong L acid decrease in turn. The high proportion of medium-strong B acid with isomerization performance in the upper catalyst is conducive to the isomerization reaction of the raw material oil entering the catalyst bed in a short contact time. With the flow of the raw material, the larger mesopore diameter is more conducive to the rapid passage of single branched-chain isomers that have undergone isomerization reaction through the catalyst bed, and the proportion of medium-strong B acid also decreases, preventing single branched-chain isomers from isomerizing again, thereby achieving the purpose of ensuring a certain isomerization degree while reducing the opportunity of excessive isomerization reaction, improving the yield of the isodewaxing reaction product, and reducing the loss of viscosity index. Embodiment

[0024] The preparation method of the isomerization dewaxing catalyst I can adopt the conventional catalyst preparation method in the field.

[0025] In the catalyst carrier of the isomerization dewaxing catalyst I, the conventional *MRE type molecular sieve is one or more of ZSM-48, COK-8, EU-2, EU-11, IZM-1, SSZ-91 and ZBM-30, and preferably ZSM-48 molecular sieve; the ZSM-48 molecular sieve can be prepared by using the prior art.

[0026] The preparation method of the isomerization dewaxing catalyst II comprises the following steps:

[0027] S1, synthesizing ZSM-48 molecular sieve;

[0028] S2, preparing the ZSM-48 molecular sieve obtained in S1 into a catalyst carrier;

[0029] S3, introducing metal active components into the catalyst carrier obtained in S2.

[0030] Further, in the preparation method of the isomerization dewaxing catalyst II, the catalyst carrier forming aid such as sesbania powder and starch can also be added in step S2.

[0031] Further, in the preparation method of the isomerization dewaxing catalyst II, the metal active component loading process in step S3 can adopt the conventional loading method in the field, and can adopt impregnation method, equal volume impregnation, excess volume impregnation, spray impregnation and complexation impregnation, and after the impregnation is completed, it is dried at 80-200 DEG C for 1-15 h, and then calcined at 400-650 DEG C for 2-15 h, so as to obtain the isomerization dewaxing catalyst.

[0032] Further, in the preparation method of the isomerization dewaxing catalyst II, the synthesis of ZSM-48 molecular sieve in step S1 adopts the synthesis method provided above, and specifically as follows:

[0033] (1) under the contact condition, the silicon source, the aluminum source, the template agent and the water are mixed uniformly to obtain a gel;

[0034] (2) the gel obtained in step (1) is subjected to hydrothermal crystallization treatment, and then washed, dried and calcined to obtain hydrogen type ZSM-48 molecular sieve.

[0035] Further, in the synthesis method of the hydrogen type ZSM-48 molecular sieve, the template agent in step (1) comprises hexamethonium hydroxide and urea; preferably, the template agent further comprises urease.

[0036] Further, in the synthesis method of the hydrogen-type ZSM-48 molecular sieve, the SiO2 / Al2O3 molar ratio in the gel in step (1) is 20-600, preferably 50-200.

[0037] Further, in the synthesis method of the hydrogen-type ZSM-48 molecular sieve, the H2O / SiO2 molar ratio in step (1) is 10-60, the hexamethonium hydroxide / SiO2 molar ratio is 0.02-0.3, and the urea / SiO2 molar ratio is 0.005-0.5; the urease is added in an amount of 0.05 g / L-100 g / L, preferably 0.5 g / L-10 g / L, based on the amount of the gel.

[0038] Further, in the synthesis method of the hydrogen-type ZSM-48 molecular sieve, the silicon source in step (1) is one or more of silica sol, white carbon black, and tetraethyl orthosilicate; preferably, the silicon source is silica sol.

[0039] Further, in the synthesis method of the hydrogen-type ZSM-48 molecular sieve, the aluminum source in step (1) is one or more of aluminum hydroxide, pseudo-boehmite, aluminum isopropoxide, aluminum sulfate, and aluminum chloride; preferably, the aluminum source is pseudo-boehmite.

[0040] Further, in the synthesis method of the hydrogen-type ZSM-48 molecular sieve, the hydrothermal crystallization treatment temperature in step (2) is 30°C-200°C, preferably 40°C-185°C; and the treatment time is 0.3 h-200 h, preferably 2 h-100 h.

[0041] Further, in the synthesis method of the hydrogen-type ZSM-48 molecular sieve, the hydrothermal crystallization treatment in step (2) comprises two-stage hydrothermal crystallization treatment, wherein the first-stage hydrothermal crystallization treatment can be static crystallization or dynamic crystallization, preferably dynamic crystallization; in general, the first-stage hydrothermal crystallization treatment temperature is 30°C-70°C; and the treatment time is 0.3 h-12 h, preferably 2 h-6 h. The second-stage hydrothermal crystallization treatment can be static crystallization or dynamic crystallization, preferably dynamic crystallization; the second-stage hydrothermal crystallization treatment temperature is 150°C-200°C, and the crystallization time is 10 h-200 h, preferably 20 h-100 h. Further preferably, the second-stage hydrothermal crystallization treatment temperature is 80°C-170°C higher than the first-stage hydrothermal crystallization treatment temperature, preferably 95°C-155°C higher.

[0042] Furthermore, in the above-mentioned synthesis method of hydrogen-type ZSM-48 molecular sieve, the gel obtained in step (1) is preferably further mixed with ZSM-48 molecular sieve and then subjected to hydrothermal crystallization treatment, wherein the amount of ZSM-48 molecular sieve added is 0.01% to 6% of the amount of silicon dioxide added. The ZSM-48 molecular sieve can be a product obtained by the synthesis method of the present invention, or it can be a commercially available ZSM-48 molecular sieve product after dealkalization of metal ions.

[0043] Furthermore, in the above-mentioned method for synthesizing hydrogen-type ZSM-48 molecular sieve, the washing in step (2) can be any of the existing washing methods in the art, specifically, it can be washed with water several times, generally 1-6 times, until the filtrate is neutral.

[0044] Furthermore, in the above-mentioned synthesis method of hydrogen-type ZSM-48 molecular sieve, the drying conditions in step (2) are as follows: the drying temperature is 60℃~150℃, preferably 80℃~120℃; the drying time is 2h~24h, preferably 4h~12h.

[0045] Furthermore, in the above-mentioned synthesis method of hydrogen-type ZSM-48 molecular sieve, the calcination conditions in step (2) are as follows: the calcination temperature is 400℃~650℃, preferably 450℃~600℃; the calcination time is 2h~20h, preferably 4h~8h.

[0046] The invention will be further illustrated below with examples and comparative examples, but this does not limit the scope of the invention. The endpoints and values ​​of the disclosed ranges are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, endpoint values ​​of various ranges, endpoint values ​​of various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. Unless otherwise specified, all contents in the following examples are weight percentages. The specific surface area and pore volume of the samples of this invention were determined by N2 adsorption-desorption using an ASAP 2405 physical adsorption instrument. The medium-strong Brønsted acid and medium-strong Leucite acid of the samples of this invention were determined by pyridine adsorption-desorption using a Nicolet iS20 Fourier transform infrared spectrometer. The medium-strong Brønsted acid refers to the difference between the amount of Brønsted acid at a pyridine desorption temperature of 300℃ and the amount of Brønsted acid at a desorption temperature of 450℃. The medium-strong Leucite acid refers to the difference between the amount of Leucite at a pyridine desorption temperature of 300℃ and the amount of Leucite at a desorption temperature of 450℃.

[0047] Example 1

[0048] ZSM-48 molecular sieve with SiO2 / Al2O3 of 150 was synthesized according to the method provided in US6923949A, and then the synthesized ZSM-48 molecular sieve was exchanged with 1 mol / L NH4Cl solution at 80°C for 2 h, and the process was repeated three times, and hydrogen type ZSM-48 molecular sieve S-1 was obtained after being calcined at 550°C for 4 h. 140 g of the above hydrogen type ZSM-48 molecular sieve (dry basis, the same below) was uniformly mixed with 60 g of alumina, 1.15 mL of concentrated nitric acid (65% by mass) and an appropriate amount of water were added, and the mixture was kneaded and extruded into strips. The formed carrier was dried at 100°C for 6 h and calcined at 550°C for 3 h to obtain the carrier. The noble metal Pt was impregnated by the saturation impregnation method, the Pt loading amount was 0.41 wt% of the carrier, and the isomerization dewaxing catalyst I was obtained after being dried at 80°C for 4 h and calcined at 450°C for 4 h, and the catalyst number was E-1.

[0049] Example 2

[0050] 30 g of urea, 18.9 g of hexamethonium hydroxide solution (25% by mass), 200 g of silica sol (30% by mass), 0.51 g of pseudoboehmite, 566 g of water, 1.66 g of urease, and 0.3 g of ZSM-48 seed crystals were uniformly mixed to form a gel, and after dynamic crystallization at 30°C for 6 h, the temperature was increased to 190°C for hydrothermal crystallization for 20 h. The product obtained after crystallization was washed, then dried at 80°C for 5 h and calcined at 550°C for 3 h to obtain hydrogen type ZSM-48 molecular sieve S-2. 80 g of the above hydrogen type ZSM-48 molecular sieve was uniformly mixed with 120 g of alumina and 2 g of sesbania powder, 1.15 mL of concentrated nitric acid (65% by mass) and an appropriate amount of water were added, and the mixture was kneaded and extruded into strips. The formed carrier was dried at 100°C for 6 h and calcined at 550°C for 4 h to obtain the carrier. The noble metal Pt was impregnated by the saturation impregnation method, the Pt loading amount was 0.30 wt% of the carrier, and the isomerization dewaxing catalyst II was obtained after being dried at 120°C for 4 h and calcined at 500°C for 3 h, and the catalyst number was E-2.

[0051] Example 3

[0052] A gel was formed by uniformly mixing 0.3 g of urea, 94.6 g of a hexamethonium hydroxide solution (25% by mass), 60 g of white carbon black, 0.92 g of pseudoboehmite, 109 g of water, 0.09 g of urease, and 0.4 g of ZSM-48 seed crystals, and the gel was dynamically crystallized at 70°C for 6 h, and then hydrothermally crystallized at 170°C for 48 h. The product obtained after the crystallization was completed was washed, and then dried at 100°C for 4 h and calcined at 500°C for 4 h, thereby obtaining a hydrogen-type ZSM-48 molecular sieve S-3. 110 g of the hydrogen-type ZSM-48 molecular sieve described above, 90 g of alumina, and 2 g of sesbania powder were uniformly mixed, 1.15 mL of concentrated nitric acid (65% by mass) and an appropriate amount of water were added, and kneading and extrusion were performed. The support after the molding was dried at 90°C for 8 h and calcined at 550°C for 4 h, thereby obtaining a support. The support was impregnated with a noble metal Pt by a saturation impregnation method, the Pt loading amount was 0.25% by mass of the support, and the isomerization and dewaxing catalyst II was obtained after drying at 110°C for 6 h and calcination at 500°C for 4 h. The catalyst number is E-3.

[0053] Example 4

[0054] A gel was formed by uniformly mixing 12 g of urea, 283.7 g of a hexamethonium hydroxide solution (25% by mass), 200 g of silica sol (30% by mass), 3.12 g of aluminum hydroxide, 727 g of water, 10.8 g of urease, and 0.1 g of ZSM-48 seed crystals, and the gel was dynamically crystallized at 60°C for 4 h, and then hydrothermally crystallized at 175°C for 36 h. The product obtained after the crystallization was completed was washed, and then dried at 100°C for 4 h and calcined at 500°C for 4 h, thereby obtaining a hydrogen-type ZSM-48 molecular sieve S-4. 100 g of the hydrogen-type ZSM-48 molecular sieve described above, 100 g of alumina, and 2 g of sesbania powder were uniformly mixed, 1.15 mL of concentrated nitric acid (65% by mass) and an appropriate amount of water were added, and kneading and extrusion were performed. The support after the molding was dried at 90°C for 8 h and calcined at 550°C for 4 h, thereby obtaining a support. The support was impregnated with a noble metal Pt by a saturation impregnation method, the Pt loading amount was 0.34% by mass of the support, and the isomerization and dewaxing catalyst II was obtained after drying at 110°C for 4 h and calcination at 500°C for 4 h. The catalyst number is E-4.

[0055] Example 5

[0056] A gel was formed by mixing 15 g of urea, 189.1 g of hexamethonium hydroxide solution (25% by mass), 200 g of silica sol (30% by mass), 1.02 g of pseudoboehmite, 258 g of water, 3.8 g of urease, and 0.1 g of ZSM-48 seeds, and the gel was dynamically crystallized at 50°C for 5 h, and then hydrothermally crystallized at 180°C for 24 h. The product obtained after the crystallization was completed was washed, dried at 120°C for 3 h, and calcined at 450°C for 8 h, thereby obtaining hydrogen-type ZSM-48 molecular sieve S-5. 96 g of the hydrogen-type ZSM-48 molecular sieve described above, 104 g of alumina, and 2 g of sesbania powder were mixed uniformly, 1.15 mL of concentrated nitric acid (65% by mass) and an appropriate amount of water were added, and the mixture was kneaded and extruded into strips. The support after the extrusion was dried at 80°C for 8 h and calcined at 550°C for 4 h, thereby obtaining a support. The support was impregnated with a noble metal Pt by a saturation impregnation method, dried at 100°C for 4 h, and calcined at 450°C for 6 h, thereby obtaining an isodewaxing catalyst II, and the catalyst was assigned a catalyst number E-5.

[0057] Example 6

[0058] The catalyst grading scheme for the isodewaxing reaction zone was isodewaxing catalyst I E-1 : isodewaxing catalyst II E-2 = 3:2, and the reaction conditions are shown in Table 4. The catalyst used in the hydrofining reaction zone was a commercial catalyst FMTA-2 developed by SINOPEC Dalian (Fushun) Petrochemical Research Institute, the hydrofining reaction pressure was 13 MPa, the hydrogen to oil volume ratio was 800, and the volume space velocity was 0.8 h -1 .

[0059] Example 7

[0060] The catalyst grading scheme for the isodewaxing reaction zone was isodewaxing catalyst I E-1 : isodewaxing catalyst II E-3 = 5:3, and the reaction conditions are shown in Table 4. The catalyst used in the hydrofining reaction zone and the reaction conditions were the same as in Example 6.

[0061] Example 8

[0062] The catalyst grading scheme for the isodewaxing reaction zone was isodewaxing catalyst I E-1 : isodewaxing catalyst II E-4 = 1:1, and the reaction conditions are shown in Table 4. The catalyst used in the hydrofining reaction zone and the reaction conditions were the same as in Example 6.

[0063] Example 9

[0064] The catalyst grading scheme for the isodewaxing reaction zone was isodewaxing catalyst I E-1 : isodewaxing catalyst II E-5 = 3:4, and the reaction conditions are shown in Table 4. The catalyst used in the hydrofining reaction zone and the reaction conditions were the same as in Example 6.

[0065] Comparative Example 1

[0066] The isodewaxing reaction zone catalyst grading scheme was: all isodewaxing catalyst I E-1 was loaded, the reaction conditions were as shown in Table 4, and the hydrogenation finishing reaction zone was loaded with catalyst and had the same reaction conditions as in Example 6.

[0067] Comparative Example 2

[0068] The isodewaxing reaction zone catalyst grading scheme was: all isodewaxing catalyst II E-3 was loaded, the reaction conditions were as shown in Table 4, and the hydrogenation finishing reaction zone was loaded with catalyst and had the same reaction conditions as in Example 6.

[0069] The catalysts loaded using different grading schemes were evaluated for performance, the raw oil properties were as shown in Table 3, and the evaluation results were as shown in Table 4.

[0070] Table 1 Molecular sieve physical and chemical properties

[0071]

[0072] Table 2 Catalyst physical and chemical properties

[0073]

[0074] Table 3 Main properties of raw materials

[0075]

[0076] Table 4 Catalyst performance evaluation results

[0077]

[0078] The evaluation results in Table 4 show that, compared with the comparative catalyst grading scheme, the catalyst grading scheme provided by the application, when applied in the isodewaxing process of the lubricating oil fraction, the lubricating oil base oil yield and the viscosity index of the product are both improved when the pour point of the lubricating oil base oil is similar, which indicates that the catalyst grading scheme of the application significantly improves the effect in the isodewaxing process for producing base oil.

Claims

1. A method for producing lubricating oil base oil through isomerization dewaxing, characterized in that: The method includes mixing the feedstock oil with hydrogen and then reacting it in an isomerization dewaxing reaction zone. The isomerization dewaxing reaction zone is filled with at least one isomerization dewaxing catalyst, denoted as isomerization dewaxing catalyst II. In the isomerization dewaxing catalyst II, 7-26 nm mesopores account for 55%-87% of the total pore volume, the amount of medium-strong Brønsted acid accounts for 5%-18% of the total acid content, and the ratio of medium-strong Brønsted acid to medium-strong Lewis acid is 0.3-1.

8. The isomerization dewaxing catalyst II contains HZSM-48 molecular sieve; The isomerization dewaxing reaction zone includes a first catalyst bed and a second catalyst bed. According to the contact sequence with the reactants, the first catalyst bed is filled with a conventional isomerization dewaxing catalyst, referred to as isomerization dewaxing catalyst I, and the second catalyst bed is filled with isomerization dewaxing catalyst II. Compared with isomerization dewaxing catalyst I, isomerization dewaxing catalyst II has a larger proportion of 7-28 nm mesopores in the total pore volume, a smaller proportion of medium-strong Brønsted acid in the total acid content, and a lower proportion of medium-strong Brønsted acid / medium-strong Lewis acid. The volume ratio of isomerization dewaxing catalyst II to isomerization dewaxing catalyst I is 1:9 to 4:

1.

2. The method according to claim 1, characterized in that: In the isomeric dewaxing catalyst II, 7-26 nm mesopores account for 65%-80% of the total pore volume, medium-strong Brønsted acid accounts for 7%-15% of the total acid content, and the ratio of medium-strong Brønsted acid to medium-strong L acid is 0.4-1.

6.

3. The method according to claim 1, characterized in that: In the HZSM-48 molecular sieve, mesopores of 7~26nm account for 35%~80% of the total pore volume, medium-strength Benzyl acid accounts for 8%~30% of the total acid content, and the ratio of medium-strength Benzyl acid to medium-strength Lewis acid is 0.7~4.

5.

4. The method according to claim 3, characterized in that: In the HZSM-48 molecular sieve, mesopores of 7~26nm account for 40%~75% of the total pore volume, medium-strength Benzyl acid accounts for 10%~25% of the total acid content, and the ratio of medium-strength Benzyl acid to medium-strength Lewis acid is 0.8~4.

0.

5. The method according to claim 1, characterized in that: The feedstock oil needs to be treated before entering the isomerization dewaxing reaction zone to control the sulfur and nitrogen content, with the sulfur content controlled to be below 35 mg / g and the nitrogen content below 10 mg / g.

6. The method according to claim 5, characterized in that: The sulfur content should be controlled below 15 mg / g and the nitrogen content below 2 mg / g.

7. The method according to claim 1, characterized in that: The BET specific surface area of ​​the isomer dewaxing catalyst II is 140 m². 2 / g~450m 2 / g, pore volume 0.25mL / g~0.70mL / g.

8. The method according to claim 7, characterized in that: The BET specific surface area of ​​the isomer dewaxing catalyst II is 150 m². 2 / g~330m 2 / g, with a pore volume of 0.30mL / g~0.65mL / g.

9. The method according to claim 1, characterized in that: The isomerization dewaxing catalyst II includes an active metal component; the active metal component is at least one of the Group VIII noble metals Pt and Pd.

10. The method according to claim 9, characterized in that: The active metal component is Pt.

11. The method according to claim 1, characterized in that: The isomer dewaxing catalyst II also contains inorganic refractory oxides, which are one or more of alumina, titanium dioxide, silicon dioxide, boron oxide, magnesium oxide, zirconium oxide and clay. The precursors of the inorganic refractory oxides are one or more of boehmite, pseudoboehmite, diaspore, gibbsite and diaspore.

12. The method according to claim 11, characterized in that: The inorganic refractory oxide is alumina and / or silicon oxide, and the precursor of the inorganic refractory oxide is boehmite.

13. The method according to claim 11, characterized in that: The inorganic refractory oxide is aluminum oxide.

14. The method according to claim 1, characterized in that: The isomer dewaxing catalyst II, based on the final catalyst weight, has a molecular sieve content of 10wt%~90wt%, an active metal content of 0.05wt%~5wt% (calculated as metal), and an inorganic refractory oxide content of 5wt%~85wt%.

15. The method according to claim 14, characterized in that: The isomer dewaxing catalyst II, based on the final catalyst weight, has a molecular sieve content of 20wt%~70wt%, an active metal content of 0.1wt%~1.0wt% (calculated as metal), and an inorganic refractory oxide content of 30wt%~70wt%.

16. The method according to claim 1, characterized in that: After the feedstock oil is mixed with hydrogen, it passes through the isomerization dewaxing reaction zone and then enters the hydrorefining reaction zone for further reaction. The operating conditions of the hydrorefining reaction zone are: reaction temperature of 200℃~300℃, reaction pressure of 6.0MPa~18.0MPa, and volume hourly space velocity of 0.5h⁻¹. -1 ~2.8h -1 The hydrogen-to-oil volume ratio is 400:1 to 1500:

1.

17. The method according to claim 16, characterized in that: The hydrorefining reaction zone is filled with a hydrorefining catalyst; the hydrorefining catalyst support is Al2O3 or Al2O3-SiO2, and the active metal is one or both of Pt and Pd, with the active metal accounting for 0.05wt% to 1.0wt% of the catalyst by weight.

18. The method according to claim 1, characterized in that: Compared with isomer dewaxing catalyst I, the isomer dewaxing catalyst II has an increased proportion of 7-26 nm mesopores in the total pore volume by 5-57 percentage points, a decreased proportion of medium-strong Brønsted acid in the total acid content by 3-16 percentage points, and a decreased proportion of medium-strong Brønsted acid / medium-strong L-acid by 0.2-2.

2.

19. The method according to claim 18, characterized in that: Compared with isomer dewaxing catalyst I, the isomer dewaxing catalyst II has a 10-50 percentage point increase in the proportion of 7-26 nm mesopores in the total pore volume, a 4-13 percentage point decrease in the proportion of medium-strong Brønsted acid in the total acid content, and a 0.3-1.8 decrease in the ratio of medium-strong Brønsted acid to medium-strong L acid.

20. The method according to claim 1, characterized in that: The volume ratio of isomerization dewaxing catalyst II to isomerization dewaxing catalyst I is 1:4 to 7:

3.

21. The method according to claim 1, characterized in that: The isomer dewaxing catalyst I comprises a conventional *MRE type molecular sieve and an active metal component, wherein the active metal component is at least one of Group VIII noble metals Pt and Pd, and the conventional *MRE type molecular sieve is one or more of ZSM-48, COK-8, EU-2, EU-11, IZM-1, SSZ-91, and ZBM-30.

22. The method according to claim 21, characterized in that: The active metal component is Pt, and the conventional *MRE type molecular sieve is ZSM-48 molecular sieve.

23. The method according to claim 1, characterized in that: The isomer dewaxing catalyst I also contains inorganic refractory oxides, which are one or more of alumina, titanium dioxide, silicon dioxide, boron oxide, magnesium oxide, zirconium oxide and clay, and the precursors of the inorganic refractory oxides are one or more of boehmite, pseudoboehmite, diaspore, gibbsite and diaspore.

24. The method according to claim 23, characterized in that: The inorganic refractory oxide is alumina and / or silicon oxide, and the precursor of the inorganic refractory oxide is boehmite.

25. The method according to claim 23, characterized in that: The inorganic refractory oxide is aluminum oxide.

26. The method according to claim 1, characterized in that: The isomer dewaxing catalyst I, based on the final catalyst weight, has an MRE-type molecular sieve content of 25wt%~80wt%, an active metal content of 0.05wt%~5wt% (calculated as metal), and an inorganic refractory oxide content of 15wt%~70wt%.

27. The method according to claim 26, characterized in that: The isomer dewaxing catalyst I, based on the final catalyst weight, has an MRE-type molecular sieve content of 40wt%~70wt%, an active metal content of 0.1wt%~1.0wt% (calculated as metal), and an inorganic refractory oxide content of 30wt%~60wt%.

28. The method according to claim 1, characterized in that: The reaction conditions in the isomerization dewaxing reaction zone are as follows: reaction temperature 250℃~400℃, reaction pressure 2MPa~20MPa, and volume hourly space velocity 0.5h⁻¹. -1 ~4.0h -1 The hydrogen-to-oil volume ratio is 500:1 to 1400:1.

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