A method for producing a high viscosity lubricating oil base oil

Abstract

The present application belongs to the technical field of coal-based liquefaction product hydrogen isomerization, and particularly relates to a method for preparing high-viscosity lubricating oil base oil, comprising: taking coal indirect liquefaction product as raw material, contacting the coal indirect liquefaction product with modified hydrogen isomerization catalyst and performing isomerization dewaxing reaction to prepare high-viscosity base oil with a grade of 10 cSt and above; the coal indirect liquefaction product is one or more of full distillation of Fischer-Tropsch refined cutback oil / cracking cutback oil and heavy narrow distillation of Fischer-Tropsch refined cutback oil / cracking cutback oil; the modified hydrogen isomerization catalyst comprises an active component and a carrier, the carrier comprises a composite molecular sieve, and the composite molecular sieve is a combination of 30-80 wt% ZSM-48 molecular sieve and 20-70 wt% MCM-41 molecular sieve. The method of the present application can produce high-viscosity base oil with a grade of 10 cSt and above with high selectivity and high yield.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydroisomerization of coal-based liquefaction products, and particularly relates to a method for preparing high-viscosity lubricating oil base oil. BACKGROUND

[0002] The hydroisomerization catalyst is a bifunctional shape-selective catalyst, which needs both hydrogenation activity and acid centers. The hydrogenation reaction is carried out on the metal active center, and the isomerization and cracking reactions are carried out on the acid centers of the carrier. Therefore, the performance of the hydroisomerization catalyst is closely related to the carrier preparation technology and the metal loading technology.

[0003] The existing composite acid component as the carrier is mainly based on the hydrothermal synthesis method, in which a traditional molecular sieve with isomerization function (such as ZSM-5, SAPO-11, ZSM-22, ZSM-23) is synthesized in the first step, and then a second acid molecular sieve is crystallized by adding a silicon source, an aluminum source and a template agent. This method has high cost and a complex synthesis process. For example,

[0004] Patent document CN105032478A discloses a preparation method of a core-shell structure molecular sieve and an isomerization and condensation reduction catalyst; a composite molecular sieve with ZSM-22 as the core and MCM-41 as the shell is prepared by a hydrothermal synthesis method, and the isomerization and condensation reduction catalyst prepared by taking the molecular sieve as the acid component has high isomerization selectivity, especially the selectivity of multi-branched alkanes is obviously improved when used for isomerization and condensation reduction of F-T synthetic middle distillate oil.

[0005] Patent document CN112058303A discloses a composite molecular sieve with ZSM-22 as the core and MCM-48 as the shell, and a hydroisomerization dewaxing catalyst is prepared by loading Pt nanoparticles on the composite molecular sieve by a sol-gel method; and the catalyst is used for improving the catalytic performance of petroleum-based cutting oil or F-T oil.

[0006] Patent document CN106669811A discloses a ZSM-22 / MCM-22 composite molecular sieve, and a catalyst is prepared by subjecting the composite molecular sieve to tetraethyl orthosilicate-high temperature hydrothermal treatment. The acid centers of the outer layer molecular sieve are covered purposefully to avoid non-selective cracking reactions, so as to improve the yield of liquid products and the yield of target products.

[0007] Patent document CN106513035A discloses that the acid component of the catalyst is a ZSM-23 molecular sieve wrapped by MCM-41 or SBA-15 mesoporous material, the inner-to-outer ratio and the acidity of the molecular sieve are adjustable, and the catalyst is particularly suitable for long-chain alkanes, especially raw materials with high wax content, and the isomerization selectivity of multi-branched alkanes is significantly improved, which is greater than 58%.

[0008] In view of this, the existing composite molecular sieve carrier prepared hydrogen isomerization catalyst is mainly aimed at the catalytic modification of petroleum-based raw materials, and is not specifically aimed at the selective isomerization of coal indirect liquefaction products (especially coal-based long carbon chain) and the improvement of high viscosity base oil yield. SUMMARY

[0009] The purpose of the present application is to provide a method for preparing high viscosity lubricating oil base oil for specific wide distillation range and high boiling point coal indirect liquefaction raw materials, which can produce high viscosity base oil with a grade of 10 cSt and above with high selectivity and high yield.

[0010] In order to achieve the above-mentioned purpose, the technical scheme provided by the present application is as follows:

[0011] A method for preparing high viscosity lubricating oil base oil, comprising the following steps:

[0012] The coal indirect liquefaction product is contacted with the modified hydrogen isomerization catalyst to carry out isomerization dewaxing reaction, and high viscosity base oil with a grade of 10 cSt and above is prepared;

[0013] The coal indirect liquefaction product is one or more of the full distillation of Fischer-Tropsch refined reduced oil / cracking reduced oil and the heavy narrow distillation (atmospheric boiling point distillation range > 500℃) of Fischer-Tropsch refined reduced oil / cracking reduced oil;

[0014] The modified hydrogen isomerization catalyst comprises an active component and a carrier; the active component is a group VIII noble metal element, preferably palladium and / or platinum;

[0015] The carrier contains a composite molecular sieve, and the composite molecular sieve is a combination of ZSM-48 molecular sieve and MCM-41 molecular sieve; the components and their contents in the composite molecular sieve are as follows, based on the total weight of the composite molecular sieve:

[0016] The proportion of ZSM-48 molecular sieve is 30-80wt% (for example, 35wt%, 40wt%, 50wt%, 60wt%, 70wt%), preferably 40-70wt%;

[0017] The proportion of MCM-41 molecular sieve is 20-70wt% (for example, 25wt%, 40wt%, 50wt%, 55wt%, 65wt%), preferably 30-60wt%.

[0018] According to the method provided by the present application, in some embodiments, the composite molecular sieve is a combination of ZSM-48 molecular sieve and pure silicon MCM-41 molecular sieve, or a combination of ZSM-48 molecular sieve and aluminum-containing MCM-41.

[0019] According to the method provided by the present application, in some embodiments, the components in the carrier and their weight percentage are as follows, based on the total weight of the carrier:

[0020] 10-90wt% (for example, 15wt%, 20wt%, 40wt%, 60wt%, 80wt%) of composite molecular sieve, preferably 30-80wt%;

[0021] 10-90wt% (for example, 15wt%, 25wt%, 40wt%, 60wt%, 80wt%) of binder, preferably 20-70wt%.

[0022] According to the method provided by the present application, in some embodiments, the loading amount of the active component is 0.1wt%-1wt%, preferably 0.2wt%-0.4wt%, based on the total weight of the modified hydroisomerization catalyst.

[0023] According to the method provided by the present application, the coal indirect liquefaction product can be a full fraction of Fischer-Tropsch refined reduced oil, a full fraction of cracked reduced oil, a heavy narrow fraction of Fischer-Tropsch refined reduced oil, a heavy narrow fraction of cracked reduced oil.

[0024] In some embodiments, the full fraction of Fischer-Tropsch refined reduced oil / cracked reduced oil has a distillation range of initial boiling point ≥ 300°C (for example, 350°C, 400°C, 500°C) and final boiling point ≥ 600°C (for example, 650°C, 700°C, 800°C); for example, the full fraction of Fischer-Tropsch refined reduced oil / cracked reduced oil can have a distillation range of 350-750°C. The heavy narrow fraction of Fischer-Tropsch refined reduced oil / cracked reduced oil has an initial boiling point ≥ 480°C (for example, 500°C, 550°C, 600°C); for example, the heavy narrow fraction of Fischer-Tropsch refined reduced oil / cracked reduced oil can have a distillation range of 550-720°C.

[0025] According to the method provided by the present application, in some embodiments, the preparation method of the modified hydroisomerization catalyst comprises:

[0026] 1) The ZSM-48 molecular sieve, MCM-41 molecular sieve, binder and optional amaranth powder are thoroughly mixed, acid solution is added (for example, while stirring), and (for example, kneading, extruding) molding treatment (for example, molding into a cylindrical shape or a clover shape) is performed, and then the carrier is prepared after drying and calcination;

[0027] 2) The prepared carrier is immersed in the impregnation liquid in an equal volume impregnation manner, impregnation is performed, and then the modified hydroisomerization catalyst is prepared after drying and calcination.

[0028] The drying process conditions may include, for example, a drying temperature of 40-120℃ (e.g., 60℃, 90℃, 115℃), preferably 80-110℃, and a drying time of 2-8h (e.g., 2.5h, 4h, 7h), preferably 3-6h. The calcination process conditions may include, for example, a calcination temperature of 400-750℃ (e.g., 500℃, 550℃, 650℃, 700℃), preferably 450-600℃; and a calcination time of 2-5h (e.g., 2.5h, 3h, 4h).

[0029] In some embodiments, the acid in the acid solution is selected from one or more of nitric acid, citric acid, and oxalic acid;

[0030] In some embodiments, the amount of acid used as a solute in the acid solution is 1-5 wt% of the carrier (e.g., 1.5 wt%, 2 wt%, 3 wt%, 4 wt%).

[0031] In the process of preparing the catalyst in this invention, the amount of guar gum powder used is conventional and will not be elaborated here.

[0032] In some embodiments, the impregnation solution contains an active component precursor; the active component precursor is selected from one or more of tetraammineplatinum nitrate, chloroplatinic acid, ammonium chloroplatinate, ammonium chloroplatinate and dichlorotetraammonium platinum.

[0033] In some embodiments, the binder is selected from one or more of boehmite, alumina, alumina sol, and silica sol.

[0034] In some embodiments, the process conditions for the isomerization dewaxing reaction include:

[0035] The reaction temperature is 250℃~400℃ (e.g., 300℃, 350℃, 380℃);

[0036] The partial pressure of hydrogen is 2.0 MPa to 15.0 MPa (e.g., 3 MPa, 5 MPa, 10 MPa);

[0037] The mass hourly space velocity is 0.2 h. -1 ~2.0h -1 (For example, 0.3h) -1 0.5h -1 1h -1 1.5h -1 );

[0038] The hydrogen-to-oil volume ratio is 100–2000:1 (e.g., 120:1, 200:1, 800:1, 1000:1, 1500:1).

[0039] In some embodiments, the catalyst needs to be reduced by hydrogen before use, the reduction temperature is 100-500℃ (for example, 120℃, 150℃, 200℃, 300℃, 450℃), preferably 200-400℃, and the reduction time is 1-48h (for example, 2h, 5h, 10h, 20h, 40h), preferably 6-24h.

[0040] In the present application, the isomerization reaction follows a typical "pore-mouth" / "lock-key" mechanism, that is, the reaction mainly occurs at the pore mouth and outer surface of the ZSM-48 molecular sieve, and by compounding the ZSM-48 molecular sieve with the MCM-41 molecular sieve, a catalyst with appropriate acid density and multi-level pore structure can be obtained, that is, the total acid amount of the catalyst prepared by compounding the molecular sieve is lower, the proportion of weak acid is higher, and the proportion of medium-strong acid is lower, and it has appropriate acidity and multi-level pore structure (for example, the specific surface area is in the range of 240-500m 2 / g, the pore volume is in the range of 0.35-0.7cm 3 / g, and the average pore diameter is in the range of 4.0-7.0nm); in addition, the content of the MCM-41 molecular sieve also needs to be selected and controlled, and if the content is too low or too high, the yield of high-viscosity base oil with a grade of 10cSt (cSt refers to the kinematic viscosity of hydraulic oil) and above will not increase but decrease.

[0041] For the light bias raw material with a narrow distillation range, the boiling point of the raw material is generally below 580℃, and it cannot produce high-viscosity base oil and the processing difficulty is low; and for the full-range of Fischer-Tropsch refined reduced oil / cracked reduced oil (the distillation range is very wide, and the highest boiling point reaches above 700℃) and heavy narrow distillate (the distillation range is relatively narrow, and the boiling point range is 500-700℃ or above), although it can produce high-viscosity base oil, the processing difficulty is still very high. Therefore, in the process of compounding the ZSM-48 molecular sieve with the MCM-41 molecular sieve, the compounding method is also a factor to be considered, and if the compounding molecular sieve is a core-shell structure, because the outer surface of the ZSM-48 molecular sieve is wrapped with an inert MCM-41 molecular sieve shell, it will produce resistance to the diffusion, adsorption and isomerization of heavy raw material (long-chain alkane) in the catalytic process, and it is not suitable for the processing and production of heavy raw material (high-viscosity product).

[0042] Compared with the prior art, the beneficial effects of the technical scheme of the present application are as follows:

[0043] (1) By combining the ZSM-48 molecular sieve and the MCM-41 molecular sieve and physically mixing the molecular sieves, a hydrogenation isomerization catalyst with appropriate acid density and multi-level pore structure can be prepared; and the catalyst can positively catalyze the diffusion, adsorption and isomerization of heavy raw material (long-chain alkane);

[0044] (2) For specific wide-cut, high-boiling coal indirect liquefaction raw materials, the catalyst prepared by compounding ZSM-48 molecular sieve and MCM-41 molecular sieve can selectively and in high yield produce high-viscosity base oil with a grade of 10 cSt and above. DETAILED DESCRIPTION

[0045] In order to enable a detailed understanding of the technical features and content of the present application, the preferred embodiments of the present application will be described in more detail below. Although the preferred embodiments of the present application are described in the examples, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein.

[0046] <Raw material sources>

[0047] ZSM-48 molecular sieve, commercially available;

[0048] Pure-silicon MCM-41 molecular sieve, commercially available;

[0049] Aluminum-containing MCM-41 molecular sieve, commercially available.

[0050] Example 1:

[0051] 1) 40 g of ZSM-48 molecular sieve, 30 g of pure-silicon MCM-41 molecular sieve, 30.0 g of alumina, and 1.2 g of sesbania powder were uniformly mechanically mixed, an acid solution composed of 3.2 g of concentrated nitric acid (63 wt%) and 80.0 g of deionized water was added while stirring, and then kneaded in a kneader and extruded into a trilobal (diameter 1.6 mm) type in an extruder, the obtained extruded strip was dried at 120°C for 8 h and calcined at 500°C for 6 h to obtain a carrier;

[0052] 2) 0.75 g of chloroplatinic acid was completely dissolved in 80.0 mL of deionized water to prepare an impregnation solution; the impregnation solution was slowly added to the carrier obtained in step 1) for equal-volume impregnation while stirring, and after the addition was completed, it was dried in an oven at 120°C for 12 h and finally calcined at 400°C for 6 h to obtain a hydrogen isomerization catalyst A.

[0053] Example 2:

[0054] The catalyst was prepared according to Example 1, except that the pure-silicon MCM-41 molecular sieve was replaced with aluminum-containing MCM-41 molecular sieve (SiO2 / Al2O3=25), the platinum source was dichlorotetraamine platinum and the amount used was 0.56 g; a hydrogen isomerization catalyst B was obtained.

[0055] Example 3:

[0056] The catalyst preparation process is the same as in Example 1, except that the amount of pure silicon MCM-41 molecular sieve used is 14.0 g and the amount of ZSM-48 molecular sieve used is 56.0 g; thus, hydroisomerization catalyst C is obtained.

[0057] Example 4:

[0058] The catalyst preparation process is the same as in Example 1, except that the amount of pure silicon MCM-41 molecular sieve used is 38.5g and the amount of ZSM-48 molecular sieve used is 31.5g; thus, hydroisomerization catalyst D is obtained.

[0059] Example 5:

[0060] The catalyst preparation process is the same as in Example 1, except that the amount of pure silicon MCM-41 molecular sieve used is 42.0 g and the amount of ZSM-48 molecular sieve used is 28.0 g; thus, hydroisomerization catalyst E is obtained.

[0061] Example 6:

[0062] The catalyst preparation process is the same as in Example 1, except that the amount of pure silicon MCM-41 molecular sieve used is 49.0g and the amount of ZSM-48 molecular sieve used is 21.0g; thus, the hydroisomerization catalyst F is obtained.

[0063] Comparative Example 1:

[0064] 1) Weigh 70g of ZSM-48 molecular sieve, mix it evenly with 30.0g of alumina and 1.2g of guar gum powder, and add an acid solution consisting of 3.2g of concentrated nitric acid (63wt%) and 80.0g of deionized water while stirring. Knead the mixture in a kneader and then extrude it into a clover (1.6mm in diameter) shape in an extruder. Dry the resulting extruded strip at 120℃ for 8h and calcine it at 500℃ for 6h to obtain the carrier.

[0065] 2) Weigh 0.75g of chloroplatinic acid and dissolve it completely in 80.0mL of deionized water to prepare an impregnation solution. While stirring, slowly add the impregnation solution dropwise onto the support obtained in step 1) for equal-volume impregnation. After the addition is complete, dry it in an oven at 120℃ for 12h, and finally calcine it at 400℃ for 6h to obtain the hydroisomerization catalyst R1.

[0066] Comparative Example 2:

[0067] 1) Take 70 g of MCM-41 molecular sieve containing aluminum, mechanically mix it uniformly with 30.0 g of alumina and 1.2 g of sesbania powder, add an acid solution composed of 3.2 g of concentrated nitric acid (63 wt%) and 80.0 g of deionized water while stirring, knead in a kneader and then extrude into clover (diameter 1.6 mm) type in an extruder, dry the obtained shaped extruded strip at 120°C for 8 h and calcine at 500°C for 6 h to obtain a carrier;

[0068] 2) Take 0.75 g of chloroplatinic acid, completely dissolve it in 80.0 mL of deionized water to prepare an impregnation solution; slowly drop the impregnation solution onto the carrier obtained in step 1) for equal volume impregnation while stirring, dry in an oven at 120°C for 12 h after the dropping is completed, and finally calcine at 400°C for 6 h to obtain a hydroisomerization catalyst R2.

[0069] Comparative Example 3:

[0070] The catalyst is prepared according to Example 1, except that the amount of pure silicon MCM-41 molecular sieve used is 6.3 g and the amount of ZSM-48 molecular sieve used is 63.7 g; a hydroisomerization catalyst R3 is obtained.

[0071] Comparative Example 4:

[0072] The catalyst is prepared according to Example 1, except that the amount of pure silicon MCM-41 molecular sieve used is 57.4 g and the amount of ZSM-48 molecular sieve used is 12.6 g; a hydroisomerization catalyst R4 is obtained.

[0073] The catalysts obtained in each example and comparative example are tested for texture properties using conventional testing methods in the art (such as BET testing), and the test results are shown in Table 1. Acid property testing is also performed using conventional testing methods in the art, which will not be described here, and the acid amount distribution test results are shown in Table 2.

[0074] Table 1 Texture property test results of catalysts obtained in examples and comparative examples

[0075]

[0076]

[0077] Table 2 Comparison of acid properties of catalysts obtained in examples and comparative examples

[0078]

[0079] Example 7: Provide an evaluation method for the hydroisomerization catalyst obtained as above

[0080] The catalysts prepared in Examples 1-6 were respectively used to react with the feedstock of the refined bottom oil / cracking bottom oil, and the properties of the feedstock and the process parameters for evaluating the reaction were as shown in Table 3.

[0081] Table 3 Properties of the feedstock and process parameters for evaluating the reaction

[0082]

[0083] The reaction was evaluated in a 100 mL fixed bed reactor, and after the hydrogenation isomerization catalysts were packed, hydrogen was first passed through at 300°C for 4 h, and then the reaction temperature and other parameters shown in Table 2 were switched to pass the feedstock to react. The products obtained after the reaction were collected at the outlet of the separation tank and tested, and the test results were shown in Tables 4 and 5.

[0084] Table 4 Properties of the isomerization products of the feedstock 1 (refined bottom oil of heavy narrow fraction)

[0085]

[0086]

[0087] Table 5 Properties of the isomerization products of the feedstock 2 (cracking bottom oil of full fraction)

[0088]

[0089] As can be seen from the results shown in Tables 1-2, compared with the comparative examples, the catalysts prepared by the examples through the composite molecular sieve have suitable acid density, which is mainly reflected in: on the one hand, the total acid amount is lower than that of the catalyst prepared by the single ZSM-48 molecular sieve; in the case of the composite molecular sieve, especially with the increase of the amount of MCM-41 molecular sieve, the proportion of the medium-strong acid is significantly reduced (such acid sites are the main active sites of the cracking side reaction leading to the reduction of the yield of high viscosity oil), and the proportion of the weak acid beneficial to the isomerization main reaction changes less; on the other hand, the catalyst prepared by the composite molecular sieve has larger surface area and pore volume, and the multi-level pore structure thereof is beneficial to the adsorption of long carbon chain molecules and the desorption of corresponding product molecules in the reaction process, thereby being beneficial to the timely diffusion of the heavy feedstock affected by diffusion and the improvement of the isomerization reaction performance and the prevention of excessive cracking. That is, the combination effect of the specific acid properties and the multi-level pore structure of the catalyst prepared in each example is more optimal.

[0090] Compared with Comparative Example 1-2, each of the examples can realize the improvement of the yield and selectivity of high viscosity base oil with a grade of 10 cSt and above by the compounding of two molecular sieves. Compared with Comparative Examples 3-4, the examples 1-6 selectively compounding ZSM-48 molecular sieve with MCM-41 molecular sieve and preferentially selecting the ratio of the two, promote the isomerization reaction mainly occurring at the pore openings and outer surface of ZSM-48 molecular sieve, and are more conducive to improving the yield and selectivity of high viscosity base oil with a grade of 10 cSt and above.

[0091] The above has described the embodiments of the present application, the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the spirit of the present application.

Claims

1. A process for producing a high viscosity lubricating oil base oil, characterized by, The method comprises the following steps: The coal indirect liquefaction product is contacted with the modified hydroisomerization catalyst to perform isomerization dewaxing reaction, and high-viscosity base oil with a grade of 10 cSt or above is prepared; The coal indirect liquefaction product is one or more of a full fraction of a fischer-tropsch refined cutback oil / cracked cutback oil and a heavy narrow fraction of the fischer-tropsch refined cutback oil / cracked cutback oil; The modified hydroisomerization catalyst comprises an active component and a carrier; the active component is a group VIII noble metal element; The carrier comprises a composite molecular sieve; the composite molecular sieve is a combination of ZSM-48 molecular sieve and MCM-41 molecular sieve; the components and their contents in the composite molecular sieve are as follows: the ZSM-48 molecular sieve accounts for 30-80 wt%; and the MCM-41 molecular sieve accounts for 20-70 wt%. The ZSM-48 molecular sieve accounts for 30-80 wt%. The MCM-41 molecular sieve accounts for 20-70 wt%. The carrier is prepared by the following steps: the ZSM-48 molecular sieve, the MCM-41 molecular sieve, a binder and a sesbania powder are fully mixed, acid liquid is added and molding treatment is performed, and then the carrier is prepared after drying and calcination.

2. The method of claim 1, wherein, The active component in the modified hydroisomerization catalyst is palladium and / or platinum.

3. The method of claim 1, wherein, The components and their contents in the composite molecular sieve are as follows: the ZSM-48 molecular sieve accounts for 40-70 wt%; and the MCM-41 molecular sieve accounts for 30-60 wt%. The ZSM-48 molecular sieve accounts for 40-70 wt%. The MCM-41 molecular sieve accounts for 30-60 wt%.

4. The method of claim 1, wherein, The composite molecular sieve is a combination of ZSM-48 molecular sieve and pure-silicon MCM-41 molecular sieve, or a combination of ZSM-48 molecular sieve and aluminum-containing MCM-41.

5. The method of claim 1, wherein, The components and their weight percentages in the carrier are as follows: 10-90 wt% of the composite molecular sieve; and 10-90 wt% of the binder. The components and their weight percentages in the carrier are as follows: 30-80 wt% of the composite molecular sieve; and 20-70 wt% of the binder. The loading amount of the active component in the modified hydroisomerization catalyst is 0.1 wt%-1 wt% based on the total weight of the modified hydroisomerization catalyst.

6. The method of claim 5, wherein, The loading amount of the active component in the modified hydroisomerization catalyst is 0.2 wt%-0.4 wt% based on the total weight of the modified hydroisomerization catalyst. The distillation range of the full fraction of the fischer-tropsch refined cutback oil / cracked cutback oil is ≥300℃ for the initial boiling point and ≥600℃ for the final boiling point; and the initial boiling point of the heavy narrow fraction of the fischer-tropsch refined cutback oil / cracked cutback oil is ≥480℃. The preparation method of the modified hydroisomerization catalyst comprises the following steps:

7. The method of claim 1, wherein, 1) the ZSM-48 molecular sieve, the MCM-41 molecular sieve, a binder and a sesbania powder are fully mixed, acid liquid is added and molding treatment is performed, and then the carrier is prepared after drying and calcination; 8. The method of claim 7, wherein, 2) the prepared carrier is immersed in an impregnation liquid in an equal-volume manner for impregnation, and then the modified hydroisomerization catalyst is prepared after drying and calcination.

9. The method of claim 1, wherein, The acid in the acid liquid is selected from one or more of nitric acid, citric acid and oxalic acid; 10. The method of claim 1, wherein, The amount of the acid as a solute in the acid liquid is 1-5 wt% of the carrier. ​ ​ 11. The method of claim 10, wherein, ​ ​ 12. The method of claim 10, wherein, The impregnation solution contains an active component precursor; the active component precursor is selected from one or more of tetraammineplatinum nitrate, chloroplatinic acid, ammonium chloroplatinate, ammonium chloroplatous acid and dichlorotetraammineplatinum.

13. The method of claim 1, wherein, The binder is selected from one or more of pseudoboehmite, alumina, aluminum sol and silica sol.

14. The method of claim 1, wherein, The process conditions of the isomerization dewaxing reaction include: The reaction temperature is 250℃ to 400℃; The hydrogen partial pressure is 2.0MPa to 15.0MPa; mass velocity of 0.2 h -1 ~2.0 h -1 ; The hydrogen to oil volume ratio is 100 to 2000:1.

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