A process for the production of a lubricating oil base stock from fischer-tropsch soft wax

Abstract

The application discloses a hydroisomerization catalyst and a method for processing Fischer-Tropsch synthesis soft wax into lubricating base oil. The hydroisomerization catalyst is a combined catalyst, comprising catalyst A and catalyst B; wherein the catalyst A is a platinum and / or palladium loaded molecular sieve with a TON structure, and the catalyst B is a platinum and / or palladium loaded molecular sieve with a *MRE structure. The catalyst is used for processing Fischer-Tropsch synthesis soft wax into lubricating base oil. After vacuum distillation of a Fischer-Tropsch synthesis soft wax raw material, a fraction with a distillation temperature greater than 550 DEG C is removed by evaporation, and a fraction with a distillation temperature less than or equal to 550 DEG C is introduced into a hydroisomerization reaction zone. Hydroisomerization and moderate cracking of the soft wax are completed on the hydroisomerization catalyst based on the combined TON structure and *MRE structure molecular sieve shape channel and specific catalytic performance, and a hydroisomerization cracking oil is obtained. The obtained hydroisomerization cracking oil can be processed into low pour point and high viscosity index lubricating base oil by a supplemental refining-fractionation process with a high yield.

Description

Technical Field

[0001] This application relates to a hydroisomerization catalyst and its method for processing Fischer-Tropsch synthetic wax into lubricating oil base oil. Specifically, it relates to a method for producing Group III+ base oil as the main product through hydroconversion of Fischer-Tropsch synthetic wax as raw material, which belongs to the petrochemical field. Background Technology

[0002] With the increasing trend of heavier and lower-quality crude oil and increasingly stringent environmental regulations, my country has set higher and higher performance requirements for refined oil products. Against this backdrop, the pace of upgrading lubricant standards is accelerating. Group I and Group II base oils produced using traditional processes can no longer meet the needs of current engine oils and industrial oils. Developing advanced lubricant base oil production processes to produce base oils that meet Group III and higher standards is essential to satisfying consumer demand.

[0003] Traditional lubricating oil base oil production primarily employs the three-step process (solvent refining, solvent dewaxing, and clay refining). This method removes non-ideal components (polycyclic aromatic hydrocarbons, polar substances, etc.) from the oil through physical separation, retaining only high viscosity index and low pour point hydrocarbon components to produce qualified lubricating oil base oil. This production method cannot alter the existing hydrocarbon structure in the oil, and the properties of the base oil depend on the properties of the crude oil. The composition and content of hydrocarbons in the base oil determine its quality. Specifically, the hydrocarbon saturation determines the viscosity index and stability of the base oil, while the degree of isomerization / branching determines its low-temperature fluidity. n-Alkanes (waxes) have high pour points, and polycyclic aromatic hydrocarbons have poor oxidation stability; these are not ideal components for base oil. However, by using chemical methods, such as supplemental refining, hydrocracking, catalytic dewaxing, isomerization dewaxing, and hydrogenation saturation, these components can be transformed into ideal components, thereby significantly improving the performance of the base oil.

[0004] Fischer-Tropsch waxes are the main products of the Fischer-Tropsch synthesis reaction of syngas (CO and H2). They are primarily composed of long-chain alkanes and can be further hydrogenated to produce liquid fuels and chemicals. Fischer-Tropsch waxes are mainly composed of straight-chain alkanes and contain almost no sulfur, nitrogen, or aromatics, making them a high-quality feedstock for Group III+ high-grade lubricating oils. The key technical points for converting Fischer-Tropsch wax products into high-grade lubricating oil base oils are improving the low-temperature flow properties of the oil while maintaining a high viscosity index, i.e., lowering the pour point. This can be achieved through hydrocracking and hydroisomerization reactions.

[0005] Numerous related patents have been published both domestically and internationally. For example, US5834522 discloses a method for producing lubricating oil base oil using Fischer-Tropsch synthesis products as raw materials. The Fischer-Tropsch synthesis products undergo hydroisomerization in a hydroisomerization reaction zone, and the resulting oil is separated by distillation. The bottoms of the distillation column are then dewaxed to obtain oil and non-oil fractions. US5882505 discloses a method for producing lubricating oil base oil by converting Fischer-Tropsch synthesis waxes with a boiling point greater than 370°C using a countercurrent reactor. The raw materials are contacted with a hydroisomerization catalyst in a fixed-bed reactor, and the reaction product is contacted with a hydrodewaxing catalyst in at least one fixed-bed reactor to obtain the target product. The hydroisomerization reaction product flows countercurrently with hydrogen-containing gas. CN1688674 discloses a multi-step method for preparing heavy lubricating oil base oil from Fischer-Tropsch wax, comprising: in a first hydrodewaxing step, hydrodewaxing the wax to obtain a partially dewaxed heavy base oil fraction isomerization product; then, in one or more successive hydrodewaxing steps, hydrodewaxing the heavy lubricating oil fraction to remove hydrocarbons below the heavy lubricating oil fraction, thereby obtaining heavy lubricating oil base oil. CN1703488 discloses a method for preparing fuel and lubricating oil base oil from Fischer-Tropsch wax, comprising: (1) hydrodewaxing the Fischer-Tropsch wax to prepare an isomerization product containing fuel and partially hydrodewaxed base oil fractions; (2) separating the two fractions; (3) separating the partially hydrodewaxed base oil fraction into a heavy fraction and a lower boiling point fraction; and (4) further hydrodewaxing the lower boiling point fraction and the heavy fraction to prepare a lubricating oil base oil including heavy lubricating oil base material. CN101230290 discloses a method for producing solvent oil, lubricating oil base oil, and heavy wax from Fischer-Tropsch synthetic wax. The method involves fractionating the full-fraction product obtained from the wax conversion in a supplementary refining zone to obtain a light solvent oil fraction. The base oil fraction is then separated and subjected to hydroisomerization. The remaining heavy fraction is directly refined to obtain a decolorized wax. US7198710 discloses a method for producing high viscosity index lubricating oil base oil from Fischer-Tropsch wax. This method first fractionates the Fischer-Tropsch wax to obtain light and heavy components, then performs hydroisomerization dewaxing on each to lower the pour point, resulting in a light lubricating oil base oil with a satisfactory pour point. During the hydroisomerization dewaxing of the heavy components, since the pour point is unacceptable, solvent dewaxing is used to further lower the pour point of the heavy components, finally yielding a heavy lubricating oil base oil product with a satisfactory pour point.

[0006] Currently, the conversion of Fischer-Tropsch synthetic waxes in China is mainly achieved through hydrocracking, used to produce high-cetane diesel components. After atmospheric distillation, the reaction products produce a large amount of Fischer-Tropsch synthetic wax hydrocracking tail oil, which appears as a wax paste or viscous substance at room temperature, hence also called Fischer-Tropsch synthetic soft wax. Fischer-Tropsch synthetic soft wax can be hydroisomerized to produce high-viscosity-index Group III+ lubricating oil base oils. However, under current processing technology, this soft wax is recycled back to the hydrocracking reactor for continued diesel production, generating large amounts of naphtha and gaseous hydrocarbons as byproducts, wasting valuable Fischer-Tropsch synthetic wax resources that could be used to produce Group III+ lubricating oil base oils. Compared to Fischer-Tropsch synthetic hard wax, Fischer-Tropsch synthetic soft wax, due to its hydrocracking conversion, has a significantly lower pour point and contains a large amount of branched long-chain alkanes, as well as some olefins. In the process of producing Group III+ lubricating oil base oils through hydroisomerization, the branched long-chain alkanes in Fischer-Tropsch synthetic waxes are more prone to cracking during further hydroisomerization compared to normal long-chain alkanes. Simultaneously, the olefins contained in the waxes are more likely to adsorb onto the acidic sites of the catalyst, leading to excessive reactions (hydrocracking). Furthermore, the wide-range Fischer-Tropsch synthetic waxes exhibit significant differences in reaction rate constants and apparent activation energies due to the varying carbon chain lengths of the alkane components. At the same reaction temperature, the yields of the isomers obtained after conversion of these mixtures of normal-chain alkanes with different carbon chain lengths vary considerably, making it difficult to simultaneously achieve deep isomerization and inhibit cracking. Therefore, achieving high-yield production of Group III+ lubricating oil base oils from Fischer-Tropsch synthetic waxes is challenging. Summary of the Invention

[0007] According to one aspect of this application, a hydroisomerization catalyst is provided. This catalyst is based on a noble metal / molecular sieve catalyst with specific catalytic properties and a shape-selective pore structure combining TON and *MRE molecular sieves. This process enables the high-selectivity conversion of various components in the Fischer-Tropsch synthesis soft wax feedstock, such as n-chain alkanes, branched long-chain alkanes, and olefins, into isomers, thereby achieving high-yield production of Group III+ lubricating oil base products.

[0008] The hydroisomerization catalyst is characterized in that it comprises catalyst A and catalyst B; wherein:

[0009] The catalyst A comprises an active component A and a support A, wherein the active component A is platinum and / or palladium, and the support A is selected from at least one molecular sieve having a TON structure; the total acidity of the catalyst A is 200–600 μmol / g, the acidity on the outer surface is 30–100 μmol / g, and the mesopore volume is 0.20–0.60 ml / g; the mass content of the active component A in the catalyst A is 0.2–0.8 wt%.

[0010] The catalyst B comprises an active component B and a support B, wherein the active component B is platinum and / or palladium, and the support B is selected from [a group consisting of...]. * At least one of the molecular sieves with MRE structure; the total acidity of the catalyst B is 100-400 μmol / g, the acidity of the outer surface is 10-50 μmol / g, the mesopore volume is 0.30-0.80 ml / g, and the mass content of the active component B in the catalyst B is 0.1-0.6 wt%.

[0011] The mass content of active component A in catalyst A is expressed as the mass content of platinum and palladium metal elements; the mass content of active component B in catalyst B is expressed as the mass content of platinum and palladium metal elements.

[0012] Preferably, the total acidity of catalyst A is 300–500 μmol / g. More preferably, the total acidity of catalyst A is 340–480 μmol / g.

[0013] Preferably, the surface acidity of catalyst A is 50–80 μmol / g. More preferably, the total acidity of catalyst A is 60–75 μmol / g.

[0014] Preferably, the mesoporous volume of catalyst A is 0.30–0.50 ml / g. More preferably, the mesoporous volume of catalyst A is 0.32–0.45 ml / g.

[0015] Preferably, the active component A has a mass content of 0.3 to 0.6 wt% in catalyst A. More preferably, the active component A has a mass content of 0.3 to 0.5 wt% in catalyst A.

[0016] Preferably, the total acidity of catalyst B is 200–300 μmol / g.

[0017] Preferably, the surface acidity of catalyst B is 20–40 μmol / g.

[0018] Preferably, the mesoporous volume of catalyst B is 0.30–0.60 ml / g. More preferably, the mesoporous volume of catalyst B is 0.40–0.57 ml / g.

[0019] Preferably, the active component B has a mass content of 0.2–0.5 wt% in catalyst B. More preferably, the active component B has a mass content of 0.25–0.45 wt% in catalyst B.

[0020] Preferably, the volume ratio of catalyst A to catalyst B is 1:10-10:1. More preferably, the volume ratio of catalyst A to catalyst B is 1:6-6:1. Even more preferably, the volume ratio of catalyst A to catalyst B is 1:5-5:1. Still more preferably, the volume ratio of catalyst A to catalyst B is 1:3-2:1.

[0021] Preferably, the molecular sieve with the TON structure is selected from at least one of ZSM-22 molecular sieve, ZSM-22 molecular sieve containing metal heteroatoms, Theta-1 molecular sieve, KZ-2 molecular sieve, ISI-1 molecular sieve, and NU-10 molecular sieve; wherein the metal heteroatoms in the ZSM-22 molecular sieve containing metal heteroatoms are selected from at least one of Zn, Mg, Mn, Co, Cr, Cu, Fe, Cd, and Ni.

[0022] Preferably, the molecular sieve with the *MRE structure is selected from at least one of ZSM-48 molecular sieve and ZSM-48 molecular sieve containing metal heteroatoms; the metal heteroatoms in the ZSM-48 molecular sieve containing metal heteroatoms are selected from at least one of Zn, Mg, Mn, Co, Cr, Cu, Fe, Cd, and Ni.

[0023] Preferably, catalyst A is located above catalyst B. During the hydroisomerization reaction, the reactants are contacted sequentially with catalyst A and catalyst B.

[0024] According to another aspect of this application, a method for processing Fischer-Tropsch synthetic wax into lubricating oil base oil is provided. The Fischer-Tropsch synthetic wax feedstock can be processed through vacuum distillation-hydroisomerization-supplementary refining-fractionation to obtain a lubricating oil base oil with low pour point and high viscosity index in high yield.

[0025] The invention concept is as follows: After vacuum distillation, the fraction above 550°C of the Fischer-Tropsch synthetic soft wax feedstock is removed. The fraction below or equal to 550°C enters the hydroisomerization reaction zone. Based on the shape-selective pores of molecular sieves with combined TON and *MRE structures and possessing specific catalytic properties, the soft wax undergoes hydroisomerization and moderate cracking to obtain hydroisomerized cracked oil. The hydroisomerized cracked oil enters the supplementary refining reaction zone for further processing, where the small amount of unsaturated olefins generated during the hydroisomerization cracking process is hydrogenated to saturate the crude product. The crude product is then fractionated in an atmospheric / vacuum distillation tower to obtain base oil, diesel oil, naphtha, and other products.

[0026] The method for processing Fischer-Tropsch synthetic soft wax into lubricating oil base oil is characterized by comprising the following steps:

[0027] a) Fischer-Tropsch synthesized soft wax enters a vacuum distillation column, where heavy oil fractions above 550°C are separated to obtain fractions below or equal to 550°C.

[0028] b) The fraction with a temperature of less than or equal to 550°C obtained in step a) is mixed with hydrogen and introduced into the hydroisomerization reaction zone, where it is contacted with the hydroisomerization catalyst to carry out the hydroisomerization reaction and obtain hydroisomerized cracked oil.

[0029] c) The hydroisomerized cracked oil obtained in step b) enters the supplementary refining reaction zone and comes into contact with supplementary refining catalyst C to carry out a supplementary refining reaction, yielding a crude product;

[0030] d) Fractionate the crude product obtained in step c) to obtain a product including lubricating oil base oil;

[0031] The hydroisomerization catalyst mentioned in step b) is selected from at least one of the above-mentioned hydroisomerization catalysts.

[0032] Preferably, in step a), the Fischer-Tropsch synthesized soft wax contains no more than 70% n-alkane, no less than 0.5% unsaturated hydrocarbons, an initial boiling point of no less than 300°C, and a final boiling point of no more than 720°C. More preferably, in step a), the Fischer-Tropsch synthesized soft wax contains no more than 60% n-alkane, no less than 1% unsaturated hydrocarbons, an initial boiling point of no less than 320°C, and a final boiling point of no more than 680°C. Even more preferably, in step a), the Fischer-Tropsch synthesized soft wax contains no more than 40% n-alkane, no less than 3% unsaturated hydrocarbons, an initial boiling point of no less than 340°C, and a final boiling point of no more than 650°C.

[0033] Optionally, the hydroisomerization reaction described in step b) is carried out in a fixed-bed reactor.

[0034] Preferably, the reaction conditions for the hydroisomerization reaction in step b) are:

[0035] The reaction temperature is 200–450℃, the hydrogen partial pressure is 3.0–18.0 MPa, and the feedstock oil volume hourly space velocity is 0.4–4.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200:1 to 2000:1.

[0036] More preferably, the reaction conditions for the hydroisomerization reaction in step b) are:

[0037] The reaction temperature was 300–400℃, the hydrogen partial pressure was 3.0–12.0 MPa, and the feedstock oil volume hourly space velocity was 0.5–2.0 h⁻¹. -1 The hydrogen-to-oil ratio is 200:1 to 1000:1.

[0038] Optionally, in the method, the reactor for the supplementary refining reaction in step c) is connected in series with the reactor for the hydroisomerization reaction in step b), and the hydroisomerized cracked oil flows from the hydroisomerization reactor into the supplementary refining reactor.

[0039] Preferably, the reaction conditions for the supplementary purification reaction in step c) are as follows:

[0040] The reaction temperature is 160–360℃, the hydrogen partial pressure is 3.0–18.0 MPa, and the feedstock volume hourly space velocity is 0.5–5.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200:1 to 2000:1;

[0041] More preferably, the reaction conditions for the supplementary purification reaction in step c) are:

[0042] The reaction temperature was 180–320℃, the hydrogen partial pressure was 5.0–15.0 MPa, and the feedstock volume hourly space velocity was 0.5–3 h⁻¹. -1 The hydrogen-to-oil ratio is 200:1 to 1000:1.

[0043] Preferably, the supplementary refining catalyst C in step c) comprises a heat-resistant inorganic oxide support and an active component C;

[0044] The heat-resistant inorganic oxide carrier is alumina and / or silicon oxide;

[0045] The active component C is at least one of platinum, palladium and iridium;

[0046] The active component C in the supplemental refining catalyst C has a mass content of 0.2–1.0 wt%. Preferably, the active component C in the supplemental refining catalyst C has a mass content of 0.4–0.7 wt%.

[0047] Preferably, the supplementary refining catalyst C includes an auxiliary component C, which is selected from at least one of cobalt, nickel, molybdenum, and tungsten.

[0048] Preferably, the mass content of the auxiliary component C in the supplemental refining catalyst C is 0.2 to 1.0 wt%.

[0049] Optionally, step d) is: the crude product obtained in step c) is sequentially fed into an atmospheric distillation tower and a vacuum distillation tower for fractionation to obtain lubricating oil base oil, naphtha and diesel.

[0050] In this application, the total acidity of the catalyst was tested using pyridine as a probe molecule; the acidity of the outer surface was tested using 2,6-di-tert-butylpyridine as a probe molecule.

[0051] This application achieves high-yield conversion of Fischer-Tropsch synthetic wax (320–550 °C) into Group III+ lubricating oil base products through fractionation of heavy components and the use of specific combinations and properties of hydroisomerization catalysts. The beneficial effects of this application include, but are not limited to:

[0052] (1) It avoids the unbalanced reaction caused by the difference in reaction rate constant and apparent activation energy of alkane components with different carbon chain lengths in the Fischer-Tropsch synthesis of soft wax with a wide distillation range, and takes into account both deep isomerization and crack suppression.

[0053] (2) It inhibits the cracking of olefins in Fischer-Tropsch synthetic soft wax, thus avoiding the loss of base oil yield caused by olefin cracking.

[0054] (3) The stepwise conversion of straight-chain and low-branched long alkanes in Fischer-Tropsch synthesis of soft wax was achieved by using a combination of specific catalysts.

[0055] (4) The process conditions are simple, and there is no need to circulate the product of hydroisomerization. The target product can be obtained in one pass.

[0056] (5) The base oil products obtained by this method have high yield and good performance. Attached Figure Description

[0057] Figure 1 This is a process flow diagram of the method for producing lubricating oil base oil from Fischer-Tropsch synthetic soft wax as described in this application. Detailed Implementation

[0058] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0059] Unless otherwise specified, all raw materials and reagents used in this application are commercially purchased and used directly without processing. The instruments and equipment used adopt the manufacturer's recommended scheme and parameters.

[0060] In the examples, the mesopore volume of the samples was determined using a Mack ASAP2420 physical adsorption instrument via nitrogen physical adsorption.

[0061] In this embodiment, the total acid content of the sample was determined using pyridine adsorption infrared spectroscopy (Py-IR): 10-20 mg of sample was weighed, pressed into a circular self-supporting sheet with a diameter of 13 mm, and placed in an in-situ infrared cell. The sample was first pretreated under vacuum at 350 °C for 30 min, then cooled to room temperature to record the spectrum of a blank sample. After pyridine adsorption, the sample was heated to 150 °C and pretreated under vacuum for 30 min, then cooled to room temperature to record the pyridine adsorption spectrum. The total acid content of the sample was calculated based on the characteristic peak area.

[0062] In this embodiment, the surface acidity of the sample was determined using 2,6-di-tert-butylpyridine adsorption infrared spectroscopy (DTBPy-IR): 10-20 mg of sample was weighed, pressed into a 13 mm diameter circular self-supporting sheet, and placed in an in-situ infrared cell. The sample was first pretreated under vacuum at 350 °C for 30 min, then cooled to 150 °C to record the spectrum of a blank sample. After adsorption of 2,6-di-tert-butylpyridine, the sample was vacuumed for 30 min, and the adsorption spectrum of 2,6-di-tert-butylpyridine was recorded. Subsequently, the sample was heated to 300 °C, vacuumed for 30 min, cooled to 150 °C, and the adsorption spectrum of 2,6-di-tert-butylpyridine was recorded. The total acidity of the sample was calculated based on the characteristic peak area.

[0063] In this embodiment, the infrared spectrum was measured using a Bruker Vertex70 infrared spectrometer.

[0064] As one specific implementation method, the technical solution of this application includes the following implementation steps:

[0065] 1) Fischer-Tropsch synthesized soft wax enters a vacuum distillation column to separate heavy oil fractions with temperatures above 550°C;

[0066] 2) The fraction with a temperature of ≤550℃ obtained in step 1) is mixed with hydrogen and introduced into the hydroisomerization reaction zone. It is then contacted with the hydroisomerization catalyst in a fixed-bed reactor. The reaction temperature is 200-450℃, the hydrogen partial pressure is 3.0-18.0 MPa, and the feedstock volume hourly space velocity is 0.4-4.0 h⁻¹. -1 The reaction was carried out under conditions of hydrogen-to-oil volume ratio of 200:1-2000:1 to complete the hydroisomerization and moderate cracking of Fischer-Tropsch synthesized soft wax, and to obtain hydroisomerized cracked oil.

[0067] 3) The hydroisomerized cracked oil obtained in step 2) enters the supplementary refining reaction zone. On the supplementary refining catalyst, the reaction temperature is 160–360℃, the hydrogen partial pressure is 3.0–18.0 MPa, and the feedstock volume hourly space velocity is 0.5–5.0 h⁻¹. -1 Under the condition of a hydrogen-to-oil volume ratio of 200:1-2000:1, hydrosaturation of hydroisomerized cracked oil was completed to obtain crude product;

[0068] 4) The crude product obtained in step 3) enters the atmospheric / vacuum distillation tower and is fractionated to obtain naphtha, diesel, base oil and other products;

[0069] In step 1), the n-alkane content in the Fischer-Tropsch synthesized soft wax is not higher than 70%, the unsaturated hydrocarbon content is not lower than 0.5%, the initial boiling point is not lower than 300°C, and the final boiling point is not higher than 720°C.

[0070] The hydrogenation catalyst in step 2) is a combined catalyst, comprising catalyst A and catalyst B;

[0071] Catalyst A is a catalyst prepared by supporting platinum and / or palladium on a molecular sieve with a TON structure; catalyst B is a catalyst prepared by supporting platinum and / or palladium on a molecular sieve with a *MRE structure.

[0072] In the combined catalyst, the volume ratio of catalyst A to catalyst B is 1:10-10:1.

[0073] The method wherein, in step 1), the Fischer-Tropsch soft wax is the tail oil after hydrocracking of the hard wax generated by Fischer-Tropsch synthesis from syngas and separation of naphtha and diesel fractions. At room temperature, it is in the form of wax paste or viscous paste and is a mixture of n-chain long-chain alkanes, branched long-chain alkanes and unsaturated hydrocarbons (olefins).

[0074] The method wherein, in step 1), the content of n-alkane in the Fischer-Tropsch synthesized soft wax is not higher than 60%, the content of unsaturated hydrocarbons is not lower than 1%, the initial boiling point is not lower than 320°C, and the final boiling point is not higher than 680°C.

[0075] The method wherein, in step 1), the content of n-alkane in the Fischer-Tropsch synthesized soft wax is not higher than 40%, the content of unsaturated hydrocarbons is not lower than 3%, the initial boiling point is not lower than 340°C, and the final boiling point is not higher than 650°C.

[0076] The method wherein the hydroisomerization reaction conditions in step 2) are: temperature 300-400℃, hydrogen partial pressure 3.0-12.0 MPa, and feedstock volume hourly space velocity 0.5-2.0 h⁻¹. -1 The hydrogen-to-oil ratio is 200:1-1000:1.

[0077] The method wherein, in step 2), the molecular sieve with a TON structure in catalyst A is one or more of ZSM-22, Me-ZSM-22 (Me = one or more of Zn, Mg, Mn, Co, Cr, Cu, Fe, Cd or Ni), Theta-1, KZ-2, ISI-1 and NU-10.

[0078] The method wherein, in step 2), the molecular sieve with the *MRE structure in catalyst B is one or more of ZSM-48 and Me-ZSM-48 (Me = one of Zn, Mg, Mn, Co, Cr, Cu, Fe, Cd or Ni).

[0079] The method wherein, in step 2), the total acid content of catalyst A includes the acid content on the outer surface of the molecular sieve and the acid content inside the pores and channels of the molecular sieve.

[0080] The method wherein, in step 2), the total acidity of catalyst A is tested using pyridine as a probe molecule.

[0081] The method wherein, in step 2), the total acid content of catalyst A is 200–600 μmol (Pyridine) / g.

[0082] In the method described, the total acid content of catalyst A in step 2) is preferably 300-500 μmol (Pyridine) / g.

[0083] In the method described in step 2), the acidity of the outer surface of catalyst A is tested using 2,6-di-tert-butylpyridine as a probe molecule.

[0084] The method wherein, in step 2), the surface acidity of catalyst A is 30–100 μmol (2,6-Di-tert-butylpyridine) / g.

[0085] In the method described, the preferred amount of acid on the outer surface of catalyst A in step 2) is 50–80 μmol (2,6-Di-tert-butylpyridine) / g.

[0086] The method wherein, in step 2), the mesoporous pore volume of catalyst A is 0.20-0.60 ml / g.

[0087] The method wherein, in step 2), the preferred mesoporous pore volume of catalyst A is 0.30-0.50 ml / g.

[0088] The method wherein, in step 2), the mass content of the catalyst A supported on platinum and palladium is 0.2-0.8 wt%.

[0089] In the method described, in step 2), the catalyst A preferably has a mass content of 0.3-0.6 wt% of supported metals platinum and palladium.

[0090] The method wherein, in step 2), the total acid content of catalyst B is 100–400 μmol (Pyridine) / g.

[0091] In the method described, the catalyst B in step 2) preferably has a total acid content of 200-300 μmol (Pyridine) / g.

[0092] In the method described, in step 2), the surface acidity of catalyst B is 10–50 μmol (2,6-Di-tert-butylpyridine) / g.

[0093] In the method described, the catalyst B in step 2) preferably has an external surface acidity of 20–40 μmol (2,6-Di-tert-butylpyridine) / g.

[0094] The method wherein, in step 2), the mesoporous pore volume of catalyst B is 0.30-0.80 ml / g.

[0095] In the method described, the preferred mesoporous pore volume of catalyst B in step 2) is 0.30-0.60 ml / g.

[0096] The method wherein, in step 2), the catalyst B supported on platinum and palladium has a mass content of 0.1-0.6 wt%.

[0097] In the method described, in step 2), the catalyst B preferably contains 0.2-0.5 wt% of supported platinum and palladium.

[0098] In the method described, in step 2), the catalysts A and B are combined in such a way that A is above B, and the reaction raw materials flow through A and B sequentially.

[0099] The method wherein, in step 2), the volume ratio of catalyst A to B is 1:10-10:1.

[0100] The method wherein, in step 2), the preferred volume ratio of catalyst A and catalyst B is 1:6-6:1.

[0101] The method wherein, in step 3), the supplementary refining reactor is connected in series with the hydroisomerization reactor in step 2), and the hydroisomerized cracked oil flows from the hydroisomerization reactor into the supplementary refining reactor.

[0102] The method described herein, wherein the additional refining reaction conditions in step 3) are: temperature 180-320℃, hydrogen partial pressure 5.0-15.0 MPa, and feedstock oil volume hourly space velocity 0.5-3 h⁻¹. -1 The hydrogen-to-oil ratio is 200:1-1000:1.

[0103] The method wherein, in step 3), the added refining catalyst consists of a heat-resistant inorganic oxide as a support and a noble metal supported on the support.

[0104] The method wherein, in step 3), the heat-resistant inorganic oxide support used for supplementing the refined catalyst is alumina and / or silicon oxide.

[0105] The method wherein, in step 3), the precious metal supported on the support in the refined catalyst is one or more of platinum, palladium and iridium.

[0106] The method wherein, in step 3), the total content of noble metals supported on the support in the refined catalyst is 0.2-1.0 wt%.

[0107] In the method described, the crude product after hydrogenation saturation in step 3) enters the atmospheric and vacuum distillation system in step 4) for fractionation of the crude product.

[0108] The method described in step 4) is known in the art for its atmospheric and vacuum distillation towers, and typically includes one or more operating units for flash distillation, atmospheric distillation, and vacuum distillation towers to achieve the separation of products with different distillation ranges.

[0109] The method wherein, in step 4), the atmospheric and vacuum distillation systems fractionate the crude product to obtain naphtha, diesel and base oil products.

[0110] The atmospheric and vacuum distillation operation used in the embodiments of the present invention is well known in the art and is carried out according to the distillation range requirements of the raw materials / products.

[0111] Example 1: Preparation of Hydroisomerization Catalyst

[0112] Catalysts A and B were both prepared using a conventional impregnation method. The specific steps of this method are as follows: An aqueous solution containing platinum chloride and / or palladium chloride was prepared as the impregnation solution according to the content of the active component in the catalyst to be prepared, and an equal volume of this solution was used to impregnate the support. The content of the active component was expressed as the mass content of platinum + palladium metal elements. The impregnated catalyst was then allowed to stand at room temperature for 10 hours, dried at 110°C for 4 hours, and calcined at 500°C for 4 hours to obtain the impregnated catalyst.

[0113] The prepared catalysts A and B are loaded into a hydroisomerization reactor in a certain proportion for later use.

[0114] The contents of the support and active components, acid content, and mesopore volume in catalysts A and B are shown in Table 1.

[0115] Table 1

[0116]

[0117] Example 2: Preparation of Supplementary Refining Catalyst

[0118] The supplementary refined catalyst was prepared using a conventional impregnation method. The specific steps of the conventional impregnation method are as follows: An aqueous solution containing chloride or nitrate salts of the active and auxiliary components is prepared as the impregnation liquid according to the content of the active component and auxiliary components in the catalyst to be prepared. An equal volume of this solution is used to impregnate the support. The content of the active component is calculated by the mass content of platinum, palladium, and iridium metals; the content of the auxiliary component is calculated by the mass content of cobalt, nickel, molybdenum, and tungsten metals. The catalyst is allowed to stand at room temperature for 10 hours, dried at 110°C for 4 hours, and calcined at 500°C for 4 hours to obtain the impregnated catalyst.

[0119] Table 2

[0120]

[0121] Preparation of hydroisomerization catalysts DA1, DA2, DB1, and DB2 in Comparative Example 1

[0122] In the comparative examples, the specific preparation steps of the hydroisomerization catalysts DA1, DA2, DB1 and DB2 are the same as in Example 1; the differences are: the support, active component, acid amount or mesoporous pore volume are different.

[0123] The hydroisomerization catalyst DA1 was prepared using a conventional impregnation method. It was supported by a molecular sieve ZSM-22 with a TON structure, and platinum was the active component. Based on the weight percentage of the catalyst, the platinum content was 0.2 wt%, with the remainder being molecular sieves. The total acidity of catalyst DA1 was 580 μmol (Pyridine) / g, the external surface acidity was 120 μmol (2,6-Di-tert-butylpyridine) / g, and the mesopore volume was 0.20 ml / g.

[0124] The hydroisomerization catalyst DA2 was prepared using a conventional impregnation method. It was supported by a molecular sieve EU-1 with an EUO structure, and platinum was the active component. Based on the weight percentage of the catalyst, the platinum content was 0.2 wt%, with the remainder being molecular sieves. The total acidity of catalyst DA2 was 650 μmol (Pyridine) / g, the external surface acidity was 170 μmol (2,6-Di-tert-butylpyridine) / g, and the mesopore volume was 0.23 ml / g.

[0125] The hydroisomerization catalyst DB1 was prepared using a conventional impregnation method. It was supported by ZSM-48 molecular sieve with a *MRE structure, and platinum was the active component. Based on the weight percentage of the catalyst, the platinum content was 0.4 wt%, with the remainder being molecular sieve. Catalyst DB1 had an acidity of 700 μmol (Pyridine) / g, an external surface acidity of 120 μmol (2,6-Di-tert-butylpyridine) / g, and a mesopore volume of 0.15 ml / g.

[0126] The hydroisomerization catalyst DB2 was prepared using a conventional impregnation method. It was supported by ZSM-35 molecular sieve with a FER structure, and palladium was the active component. Based on the weight percentage of the catalyst, the palladium content was 0.5 wt%, with the remainder being molecular sieve. The catalyst DB2 had an acidity of 150 μmol (Pyridine) / g, an external surface acidity of 10 μmol (2,6-Di-tert-butylpyridine) / g, and a mesopore volume of 0.18 ml / g.

[0127] In this invention, an embodiment uses a Fischer-Tropsch synthetic soft wax as raw material, the properties of which are shown in Table 3. The properties of the raw material after vacuum distillation to remove the fraction above 550°C are shown in Table 4.

[0128] The simplified process flow diagram of this invention is as follows: Figure 1 As shown.

[0129] Example 3

[0130] The Fischer-Tropsch synthesized soft wax underwent vacuum distillation to remove the fraction above 550°C, and the fraction with a temperature of ≤550°C was fed into a hydroisomerization reactor. The hydroisomerization reactor used hydroisomerization catalysts A1 and B1, packed with A1 on top and B1 below in a 1:1 volume ratio. The reaction conditions were 333°C, 10 MPa, and a space velocity of 0.75 h⁻¹. -1 The hydrogen-to-oil ratio was 500; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 222℃, 10MPa, and space velocity 1.0h. -1 The hydrogen-to-oil ratio is 500. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5 after conversion and fractionation in this reaction process, and the properties of the base oil products are shown in Table 6.

[0131] Example 4

[0132] The Fischer-Tropsch synthesized soft wax underwent vacuum distillation to remove the fraction above 550°C, and the fraction with a temperature of ≤550°C was fed into a hydroisomerization reactor. The hydroisomerization reactor used hydroisomerization catalysts A1 and B1, packed with A1 on top and B1 below in a volume ratio of 1:2. The reaction conditions were 336°C, 8 MPa, and a space velocity of 0.8 h⁻¹. -1The hydrogen-to-oil ratio was 600; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 236℃, 8MPa, and space velocity 1.4h. -1 The hydrogen-to-oil ratio is 600. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5 after conversion and fractionation in this reaction process, and the properties of the base oil products are shown in Table 6.

[0133] Example 5

[0134] The Fischer-Tropsch synthesized soft wax underwent vacuum distillation to remove the fraction above 550°C, and the fraction with a temperature of ≤550°C was fed into a hydroisomerization reactor. The hydroisomerization reactor used hydroisomerization catalysts A1 and B1, packed with A1 on top and B1 below at a volume ratio of 1:3. The reaction conditions were 340°C, 6 MPa, and a space velocity of 0.85 h⁻¹. -1 The hydrogen-to-oil ratio was 800; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 240℃, 6MPa, and space velocity 1.3h / h. -1 The hydrogen-to-oil ratio is 800. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5, and the properties of the base oil products are shown in Table 6.

[0135] Example 6

[0136] The Fischer-Tropsch synthesized soft wax underwent vacuum distillation to remove the fraction above 550°C, and the fraction with a temperature of ≤550°C was fed into a hydroisomerization reactor. The hydroisomerization reactor used hydroisomerization catalysts A1 and B1, packed with A2 on top and B2 at the bottom in a 2:1 volume ratio. The reaction conditions were 331°C, 7 MPa, and a space velocity of 0.9 h⁻¹. -1 The hydrogen-to-oil ratio was 700; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 230℃, 7MPa, and space velocity 1.6h⁻¹. -1 The hydrogen-to-oil ratio is 700. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5 after conversion and fractionation in this reaction process, and the properties of the base oil products are shown in Table 6.

[0137] Comparative Example 2

[0138] A similar process flow to that in this embodiment was adopted. The Fischer-Tropsch synthesized soft wax underwent vacuum distillation to remove the fraction >550°C, and the fraction with a temperature of ≤550°C was fed into a hydroisomerization reactor. The hydroisomerization reactor used hydroisomerization catalysts DA1 and DB1, with DA1 on top and DB1 below, at a volume ratio of 1:1. The reaction conditions were 336°C, 10 MPa, and a space velocity of 0.75 h⁻¹. -1 The hydrogen-to-oil ratio was 500; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 220℃, 10MPa, and space velocity 1.0h. -1The hydrogen-to-oil ratio is 500. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5 after conversion and fractionation in this reaction process, and the properties of the base oil products are shown in Table 6.

[0139] Comparative Example 3

[0140] A similar process flow to that in this embodiment was adopted. The Fischer-Tropsch synthesized soft wax underwent vacuum distillation to remove the fraction >550°C, and the fraction with a temperature of ≤550°C was fed into a hydroisomerization reactor. The hydroisomerization reactor used hydroisomerization catalysts DA2 and DB2, with DA2 on top and DB2 below, at a volume ratio of 1:2. The reaction conditions were 336°C, 8 MPa, and a space velocity of 0.8 h⁻¹. -1 The hydrogen-to-oil ratio was 600; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 240℃, 8MPa, and space velocity 1.3h / h. -1 The hydrogen-to-oil ratio is 600. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5 after conversion and fractionation in this reaction process, and the properties of the base oil products are shown in Table 6.

[0141] Comparative Example 4

[0142] A similar process flow to that in this embodiment was adopted. The Fischer-Tropsch synthesized soft wax underwent vacuum distillation to remove the fraction >550°C, and the fraction with a temperature of ≤550°C was fed into a hydroisomerization reactor. The hydroisomerization reactor used the hydroisomerization catalyst DA1, and the reaction conditions were 340°C, 12 MPa, and a space velocity of 0.85 h⁻¹. -1 The hydrogen-to-oil ratio was 500; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 240℃, 12MPa, and space velocity 1.3h / h. -1 The hydrogen-to-oil ratio is 500. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5 after conversion and fractionation in this reaction process, and the properties of the base oil products are shown in Table 6.

[0143] Comparative Example 5

[0144] A similar process flow to that in this embodiment was adopted. The Fischer-Tropsch synthesized soft wax underwent vacuum distillation to remove the fraction >550°C, and the fraction with a temperature of ≤550°C was fed into a hydroisomerization reactor. The hydroisomerization reactor used hydroisomerization catalyst DB1, and the reaction conditions were 345°C, 10 MPa, and a space velocity of 0.9 h⁻¹. -1 The hydrogen-to-oil ratio was 600; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 240℃, 10MPa, and space velocity 1.2h⁻¹. -1 The hydrogen-to-oil ratio is 600. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5 after conversion and fractionation in this reaction process, and the properties of the base oil products are shown in Table 6.

[0145] Comparative Example 6

[0146] A similar process flow to that in this embodiment was adopted. The Fischer-Tropsch synthesized soft wax was subjected to vacuum distillation to remove the fraction >550°C, and the fraction with a temperature of ≤550°C was fed into a hydroisomerization reactor. The hydroisomerization reactor used hydroisomerization catalyst A1 (i.e., A1 in Example 1), and the reaction conditions were 336°C, 6 MPa, and a space velocity of 0.9 h⁻¹. -1 The hydrogen-to-oil ratio was 800; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 240℃, 6MPa, and space velocity 1.3h / h. -1 The hydrogen-to-oil ratio is 800. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5, and the properties of the base oil products are shown in Table 6.

[0147] Comparative Example 7

[0148] A similar process flow to that of this embodiment was adopted. The hydroisomerization reactor used hydroisomerization catalysts DA1 and B1 (i.e., B1 in Example 1), with DA1 on top and B1 below. The reaction conditions were 343°C, 7 MPa, and a space velocity of 0.8 h⁻¹. -1 The hydrogen-to-oil ratio was 700; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 260℃, 7MPa, and space velocity 1.6h⁻¹. -1 The hydrogen-to-oil ratio is 700. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5 after conversion and fractionation in this reaction process, and the properties of the base oil products are shown in Table 6.

[0149] Comparative Example 8

[0150] The Fischer-Tropsch synthesized soft wax is directly fed into the hydroisomerization reactor without vacuum distillation. The hydroisomerization reactor uses hydroisomerization catalysts A1 and B1, packed with A1 on top and B1 below in a 1:1 volume ratio. The reaction conditions are 343℃, 10 MPa, and a space velocity of 0.75 h⁻¹. -1 The hydrogen-to-oil ratio was 500; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 222℃, 10MPa, and space velocity 1.0h. -1 The hydrogen-to-oil ratio is 500. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5 after conversion and fractionation in this reaction process, and the properties of the base oil products are shown in Table 6.

[0151] Comparative Example 9

[0152] The Fischer-Tropsch synthesized soft wax is directly fed into the hydroisomerization reactor without vacuum distillation. The hydroisomerization reactor uses hydroisomerization catalysts A1 and B1, packed with A1 on top and B1 below at a volume ratio of 1:2. The reaction conditions are 346℃, 8 MPa, and a space velocity of 0.8 h⁻¹. -1 The hydrogen-to-oil ratio was 600; the supplemental refining reactor used supplemental refining catalyst HDF-1, and the reaction conditions were 236℃, 8MPa, and space velocity 1.4h.-1 The hydrogen-to-oil ratio is 600. The product yields obtained after the feedstocks shown in Table 3 are shown in Table 5 after conversion and fractionation in this reaction process, and the properties of the base oil products are shown in Table 6.

[0153] As shown in Table 5, compared with Comparative Examples 2-7, the method of the present invention significantly improves the base oil yield, especially the yield of the most valuable 4cSt base oil, while the yields of less valuable gaseous hydrocarbons, naphtha, and diesel are significantly reduced. Compared with Comparative Examples 8-9, the method of the present invention improves the base oil yield to a certain extent, and the yield of the most valuable 4cSt base oil is also significantly improved, while the yields of less valuable gaseous hydrocarbons, naphtha, and diesel are significantly reduced.

[0154] Meanwhile, as shown in Table 6, compared with Comparative Examples 2-7, the main product 4cSt base oil in the examples has a lower pour point, a higher viscosity index, a higher flash point, and better stability; compared with Comparative Examples 8-9, the base oil in the examples has a lower cloud point and better performance.

[0155] Table 3 Properties of Fischer-Tropsch Synthetic Soft Wax Feedstock Oil

[0156]

[0157]

[0158] Table 4 Properties of Fischer-Tropsch Synthetic Soft Wax Feedstock Oil After Vacuum Distillation to Remove the >550℃ Fraction

[0159] project raw material <![CDATA[Density (15 °C), kg / m 3 > 835 Sulfur content, ppm <2 Nitrogen content, ppm <2 Olefin content, wt% 3.8 <![CDATA[Water content, μg·g -1 > 38 Distillation, ℃ Initial boiling point 321 10％ 357 30％ 392 50％ 425 70％ 468 90％ 525 95％ 541 Final boiling point 550

[0160] Table 5 Product Yield

[0161]

[0162]

[0163] *BS is for gloss varnish.

[0164] Table 6 Properties of 4cSt Base Oils

[0165]

[0166] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A hydroisomerization catalyst, characterized in that, It includes catalyst A and catalyst B; wherein: The catalyst A comprises an active component A and a support A, wherein the active component A is platinum and / or palladium, and the support A is selected from at least one molecular sieve having a TON structure; the total acidity of the catalyst A is 200–600 μmol / g, the acidity on the outer surface is 30–100 μmol / g, and the mesopore volume is 0.20–0.60 ml / g; the mass content of the active component A in the catalyst A is 0.2–0.8 wt%. The catalyst B comprises an active component B and a support B, wherein the active component B is platinum and / or palladium, and the support B is selected from [a group consisting of...]. * At least one of the molecular sieves with MRE structure; the total acidity of the catalyst B is 100-400 μmol / g, the acidity of the outer surface is 10-50 μmol / g, the mesopore volume is 0.30-0.80 ml / g, and the mass content of the active component B in the catalyst B is 0.1-0.6 wt%.

2. The hydroisomerization catalyst according to claim 1, characterized in that, The volume ratio of catalyst A to catalyst B is 1:10-10:1; Preferably, the volume ratio of catalyst A to catalyst B is 1:6 to 6:1; More preferably, the volume ratio of catalyst A to catalyst B is 1:5-5:

1.

3. The hydroisomerization catalyst according to claim 1, characterized in that, The molecular sieve with the TON structure is selected from at least one of ZSM-22 molecular sieve, ZSM-22 molecular sieve containing metal heteroatoms, Theta-1 molecular sieve, KZ-2 molecular sieve, ISI-1 molecular sieve, and NU-10 molecular sieve; the metal heteroatoms in the ZSM-22 molecular sieve containing metal heteroatoms are selected from at least one of Zn, Mg, Mn, Co, Cr, Cu, Fe, Cd, and Ni. The molecular sieve with the *MRE structure is selected from at least one of ZSM-48 molecular sieve and ZSM-48 molecular sieve containing metal heteroatoms; the metal heteroatoms in the ZSM-48 molecular sieve containing metal heteroatoms are selected from at least one of Zn, Mg, Mn, Co, Cr, Cu, Fe, Cd, and Ni.

4. The hydroisomerization catalyst according to claim 1, characterized in that, Catalyst A is located above catalyst B.

5. A method for processing Fischer-Tropsch synthetic soft wax into a lubricating oil base oil, characterized in that, Includes the following steps: a) Fischer-Tropsch synthesized soft wax enters a vacuum distillation column, where heavy oil fractions above 550°C are separated to obtain fractions below or equal to 550°C. b) The fraction with a temperature of less than or equal to 550°C obtained in step a) is mixed with hydrogen and introduced into the hydroisomerization reaction zone, where it is contacted with the hydroisomerization catalyst to carry out the hydroisomerization reaction and obtain hydroisomerized cracked oil. c) The hydroisomerized cracked oil obtained in step b) enters the supplementary refining reaction zone and comes into contact with supplementary refining catalyst C to carry out a supplementary refining reaction, yielding a crude product; d) Fractionate the crude product obtained in step c) to obtain a product including lubricating oil base oil; The hydroisomerization catalyst mentioned in step b) is selected from the hydroisomerization catalysts described in any one of claims 1 to 4.

6. The method according to claim 5, characterized in that, The Fischer-Tropsch synthesized soft wax described in step a) has a n-alkane content of no more than 70%, an unsaturated hydrocarbon content of no less than 0.5%, an initial boiling point of no less than 300°C, and a final boiling point of no more than 720°C. Preferably, the Fischer-Tropsch synthetic soft wax in step a) contains no more than 60% n-alkane and no less than 1% unsaturated hydrocarbon; the initial boiling point is no less than 320°C and the final boiling point is no more than 680°C.

7. The method according to claim 5, characterized in that, The reaction conditions for the hydroisomerization reaction described in step b) are: The reaction temperature is 200–450℃, the hydrogen partial pressure is 3.0–18.0 MPa, and the feedstock oil volume hourly space velocity is 0.4–4.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200:1 to 2000:1; Preferably, the reaction conditions for the hydroisomerization reaction in step b) are: The reaction temperature was 300–400℃, the hydrogen partial pressure was 3.0–12.0 MPa, and the feedstock oil volume hourly space velocity was 0.5–2.0 h⁻¹. -1 The hydrogen-to-oil ratio is 200:1 to 1000:

1.

8. The method according to claim 5, characterized in that, The reaction conditions for the supplementary purification reaction described in step c) are as follows: The reaction temperature is 160–360℃, the hydrogen partial pressure is 3.0–18.0 MPa, and the feedstock oil volume hourly space velocity is 0.5–5.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200:1 to 2000:1; Preferably, the reaction conditions for the supplementary purification reaction in step c) are as follows: The reaction temperature was 180–320℃, the hydrogen partial pressure was 5.0–15.0 MPa, and the feedstock volume hourly space velocity was 0.5–3 h⁻¹. -1 The hydrogen-to-oil ratio is 200:1 to 1000:

1.

9. The method according to claim 5, characterized in that, The supplementary refining catalyst C mentioned in step c) comprises a heat-resistant inorganic oxide support and an active component C; The heat-resistant inorganic oxide carrier is alumina and / or silicon oxide; The active component C is at least one of platinum, palladium and iridium; The active component C has a mass content of 0.2–1.0 wt% in the supplemental refining catalyst C.

10. The method according to claim 5, characterized in that, Step d) involves sequentially fractionating the crude product obtained in step c) into an atmospheric distillation tower and a vacuum distillation tower to obtain lubricating oil base oil, naphtha, and diesel oil.

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