High-viscosity index base oil and preparation method thereof

Abstract

The present invention provides a high viscosity index base oil preparation method, which comprises: 1) carrying out a hydrocracking reaction to obtain a first oil product; 2) carrying out first atmospheric fractionation to obtain a first tower top component, a first side line component and a first tower bottom component; 3) carrying out an isodewaxing reaction, and carrying out a refining reaction after hydrogenation to obtain a second oil product; 4) carrying out second atmospheric fractionation to obtain a second tower top component, a second side line component and a second tower bottom component; 5) carrying out reduced pressure fractionation to obtain a first light component, light lubricating oil, medium lubricating oil, heavy lubricating oil and reduced bottom lubricating oil; and 6) carrying out steam stripping to obtain a second light component and high viscosity index base oil. The invention further provides the high-viscosity-index base oil and a preparation system thereof. According to the high-viscosity-index base oil and the preparation method thereof provided by the invention, the economic benefits of side products are improved, and high-quality and reliable domestic high-viscosity-index lubricant base oil is provided for downstream markets.

Description

Technical Field

[0001] The present invention belongs to the technical field of lubricating oil base oil production, and particularly relates to a high viscosity index base oil and a preparation method thereof. Background Art

[0002] Lubricating oil base oils are mainly divided into three categories: mineral base oils, synthetic base oils, and vegetable oil base oils. Among them, mineral oil base oils have the widest range of applications. Mineral oil base oils generally originate from the lubricating oil components in crude oil and are special mineral oil products obtained by deep refining to remove impurities such as aromatics, sulfur, and nitrogen. Their components are generally naphthenes and paraffins with a relative molecular mass of 300 - 400, belonging to the lubricating oil fraction, colorless, odorless, tasteless, chemically inert, and having excellent light and heat stability, with wide uses.

[0003] The classification standard of lubricating oil base oils in China is in line with international standards. Generally, the American API standard is adopted, and the base oils are divided into five categories: Category I, II, III, IV, and V. Among them, Categories I, II, and III are all mineral oils, Category IV is synthetic oil, and Category V is base oils not included in Categories I - IV. The main property indicators of Categories I, II, and III mineral oil base oils are: viscosity, viscosity index, sulfur content (mass fraction), saturated hydrocarbons (mass fraction), pour point, evaporation loss, oxidation stability, etc. They are mainly used for vehicle engine lubricating oils, and also for the lubrication of textile machinery, precision instruments, and compressor sealing oils; the lubrication of non - directly - contacted food processing machinery and equipment, including food industrial processing equipment such as grain and oil processing, fruit and vegetable processing, and dairy product processing. Generally, the higher the viscosity index of the base oil product, the higher the price and the greater the profit.

[0004] The domestic production processes of lubricating oil base oils mainly include the "old three sets" and full - hydrogenation. Among them, the "old three sets" process is ketone - benzene, furfural, and clay refining, mainly producing Category I base oils; while the full - hydrogenation process can produce Category II and III base oils. The domestic full - hydrogenation method for producing base oils has been studied and applied for more than 20 years, but the development is slow, and it is mainly used to produce Category II base oils, and only a small part can meet the Category III standard, while developed foreign countries mainly produce high - value - added Category III oils.

[0005] Currently, the hydrogenation process for processing lubricating oil base oils includes the patent CN202111278573.7 (a method for hydrogenation production of high viscosity index lubricating oil base oil) applied by Dalian Research Institute of Petroleum and Chemical Industry, Sinopec. This method uses waxy oil as the raw material. First, a hydrotreating reaction is carried out. After the effluent from the hydrotreating reaction is stripped with high - pressure hydrogen to remove impurities such as H2S and NH3 that affect the noble metal catalyst, it enters the isomerization - dewaxing - deep supplementary refining reaction zone to improve the low - temperature performance and stability of the oil product. Summary of the Invention

[0006] In view of the characteristics of the above-mentioned prior art, the object of the present invention is to provide a high-viscosity index base oil and a preparation method thereof. Based on the full-hydrogenation process of hydrocracking, isodewaxing, and post-hydrorefining, relying on the lubricating oil hydrogenation unit, using the third side line of vacuum fractionation, i.e., the heavy lubricating oil side line, to produce a high-viscosity index base oil meeting the API HVIⅢ4 standard, innovating the production method of Group Ⅲ base oil, which not only improves the overall economic efficiency of the unit but also provides reliable domestic high-viscosity index lubricating oil base oil for the downstream market.

[0007] To achieve the above object and other related objects, the first aspect of the present invention provides a preparation method of a high-viscosity index base oil, comprising the following steps:

[0008] 1) Mix the vacuum gas oil from the fourth side line of distillation, the hydrocracking tail oil, and the underflow of ketone-benzene dewaxing, and then carry out hydrocracking reaction to obtain the first oil product;

[0009] 2) Mix the vacuum gas oil from the fourth side line of distillation, the hydrocracking tail oil, and the underflow of ketone-benzene dewaxing, and then carry out hydrocracking reaction to obtain the first oil product;

[0010] 3) Carry out isodewaxing reaction and post-hydrorefining reaction on the first bottom component to obtain the second oil product;

[0011] 4) Carry out the second atmospheric distillation on the second oil product to obtain the second top component, the second side line component, and the second bottom component respectively;

[0012] 5) Carry out vacuum fractionation on the second bottom component to obtain the first light component, light lubricating oil, medium lubricating oil, heavy lubricating oil, and bottom lubricating oil respectively;

[0013] 6) Divide the heavy lubricating oil into the first part, the second part, and the third part of the heavy lubricating oil, and carry out steam stripping on the third part of the heavy lubricating oil to obtain the second light component and the high-viscosity index base oil.

[0014] The second aspect of the present invention provides a high-viscosity index base oil obtained by the above method.

[0015] The third aspect of the present invention provides a preparation system of a high-viscosity index base oil, which is sequentially provided with a hydrocracking reactor, a hydrocracking atmospheric distillation column, an isodewaxing reactor, a post-hydrorefining reactor, an isodewaxing atmospheric distillation column, an isodewaxing vacuum distillation column, and a stripping column along the raw material input direction. The hydrocracking reactor, the hydrocracking atmospheric distillation column, the isodewaxing reactor, the post-hydrorefining reactor, the isodewaxing atmospheric distillation column, the isodewaxing vacuum distillation column, and the stripping column are sequentially connected by pipelines.

[0016] As described above, the high viscosity index base oil and the preparation method thereof provided by the present invention have the following beneficial effects:

[0017] (1) The present invention provides a high viscosity index base oil and a preparation method thereof, which is based on the continuous production of a fully hydrogenated lubricating oil process of hydrocracking, isodewaxing, and refining after hydrogenation, and utilizes the third side line of vacuum fractionation, i.e., the heavy lubricating oil side line, to produce a high viscosity index base oil that meets the API HVIⅢ4 standard, thus opening up a production method for producing Class III base oils, innovating the production process of HVIⅢ4 high viscosity index base oils, improving the economic benefits of side line products, and providing high-quality and reliable domestically produced high viscosity index lubricating oil base oils (in compliance with the Q / SH PRD0731-2018 standard) for the downstream market.

[0018] (2) The present invention provides a high viscosity index base oil and a preparation method thereof. The high viscosity index base oil product prepared has stable and excellent quality and is sold on the market, which not only improves economic benefits but also enhances the differentiated competitiveness of domestic high-end oil products.

[0019] (3) The high viscosity index base oil and preparation method provided by the present invention, the obtained high viscosity index base oil, increases economic benefits: the side product was originally shipped as a blending component of Class II base oil, with a selling price of 6,200 yuan / ton (excluding tax); when the product is Class III base oil, the average selling price during the same period is 8,000 yuan / ton (excluding tax), the sales volume is 280 tons, and the sales revenue is 2,240,000 yuan. Compared with the Class II base oil, the efficiency is increased by 504,000 yuan, and the marginal profit increases by 1,800 yuan / ton. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Shown is a flow chart of a system for preparing a high viscosity index base oil according to the present invention.

[0021] Reference numerals

[0022] 1 Hydrocracking reactor

[0023] 2 Hydrocracking atmospheric fractionation tower

[0024] 3. Heterodewaxing Reactor

[0025] 4. Post-hydrogenation refining reactor

[0026] 5. Heterogeneous dewaxing atmospheric distillation tower

[0027] 6. Isomerization dewaxing vacuum fractionation tower

[0028] 7 Stripping Tower DETAILED DESCRIPTION

[0029] The first aspect of the present invention provides a method for preparing a high viscosity index base oil, comprising the following steps:

[0030] 1) Mix the vacuum distillation reduced fourth-line wax oil, hydrocracking tail oil, and ketone-benzene wax bottom oil, and then carry out hydrocracking reaction to obtain a first oil product;

[0031] 2) Carry out the first atmospheric distillation on the first oil product to obtain a first top component, a first side-line component, and a first bottom component respectively;

[0032] 3) Carry out isodewaxing reaction and hydrofinishing reaction on the first bottom component to obtain a second oil product;

[0033] 4) Carry out the second atmospheric distillation on the second oil product to obtain a second top component, a second side-line component, and a second bottom component respectively;

[0034] 5) Carry out vacuum distillation on the second bottom component to obtain a first light component, light lubricating oil, medium lubricating oil, heavy lubricating oil, and bottom reduced-pressure lubricating oil respectively;

[0035] 6) Divide the heavy lubricating oil into a first part, a second part, and a third part of the heavy lubricating oil, and carry out steam stripping on the third part of the heavy lubricating oil to obtain a second light component and a high viscosity index base oil.

[0036] In the above method, in step 1), the vacuum distillation reduced fourth-line wax oil is the fourth-line product of the vacuum tower in the first process of atmospheric and vacuum distillation in a general petroleum processing enterprise, that is, it is called vacuum distillation reduced fourth-line wax oil. The sulfur content in the vacuum distillation reduced fourth-line wax oil is ≤0.5%. The vacuum distillation reduced fourth-line wax oil can be obtained after the atmospheric and vacuum distillation of general crude oil, and the source is relatively wide.

[0037] In the above method, in step 1), the hydrocracking tail oil is the end product oil of the hydrocracking unit in a general petroleum processing enterprise. The sulfur content in the hydrocracking tail oil is ≤0.5%.

[0038] In the above method, in step 1), the ketone-benzene wax bottom oil is the oil product produced after temperature reduction and dewaxing in the ketone-benzene dewaxing unit of the lubricating oil product line in a general petroleum processing enterprise. Generally, the wax bottom oil produced by ketone-benzene dewaxing can be used as the ketone-benzene wax bottom oil, and the source is relatively wide.

[0039] In the above method, in step 1), the nitrogen content in the mixture of the vacuum distillation reduced fourth-line wax oil, hydrocracking tail oil, and ketone-benzene wax bottom oil is ≤1700 mg / kg.

[0040] In the above method, in step 1), the distillation range of the mixture of the vacuum distillation reduced fourth-line wax oil, hydrocracking tail oil, and ketone-benzene wax bottom oil is 320°C to 460°C, and the distillation range width is ≥80°C.

[0041] In the above distillation range, the initial boiling point of the mixture raw material should be not less than 320 °C, and the final boiling point should not exceed 460 °C. The width of the above distillation range is the temperature difference between the final boiling point and the initial boiling point.

[0042] In the above method, in step 1), the wax content in the material after mixing the vacuum distillation fourth side stream wax oil, hydrocracking tail oil, and ketone benzene underflow wax is 20 wt% - 55 wt%.

[0043] In the above method, in step 1), the water content in the material after mixing the vacuum distillation fourth side stream wax oil, hydrocracking tail oil, and ketone benzene underflow wax is ≤ 0.03 wt%.

[0044] In the above method, in step 1), the pour point of the material after mixing the vacuum distillation fourth side stream wax oil, hydrocracking tail oil, and ketone benzene underflow wax is 32 °C - 45 °C.

[0045] In the above method, in step 1), the kinematic viscosity (at 100 °C) of the material after mixing the vacuum distillation fourth side stream wax oil, hydrocracking tail oil, and ketone benzene underflow wax is 4.5 - 5.2 mm 2 / s.

[0046] In the above method, in step 1), the mass ratio of the vacuum distillation fourth side stream wax oil, hydrocracking tail oil, and ketone benzene underflow wax in the mixture is 0.8 - 1.2:0.8 - 1.2:0.8 - 1.2, preferably 1:1:1.

[0047] In the above method, in step 1), after mixing the vacuum distillation fourth side stream wax oil, hydrocracking tail oil, and ketone benzene underflow wax, it needs to be filtered to remove solid particles and impurities. Preferably, the particle size of the solid particles and impurities removed by filtration is > 25 μm.

[0048] In the above method, in step 1), the hydrocracking reaction is carried out in a hydrocracking reactor.

[0049] In the above method, in step 1), the hydrogen sulfide concentration in the recycled hydrogen introduced into the hydrocracking reaction is ≤ 1500 ppm.

[0050] In the above method, in step 1), the temperature of the hydrocracking reaction is 370 °C - 380 °C.

[0051] In the above method, in step 1), the pressure of the hydrocracking reaction is 14 MPa - 16 MPa, specifically it can be 14 MPa - 14.5 MPa, 14.5 MPa - 15.5 MPa, 15.5 - 16 MPa, preferably 14.5 - 15.5 MPa.

[0052] The above hydrocracking reaction is carried out under high temperature and high pressure conditions. Through the hydrogenation reaction, desulfurization, denitrification, saturation of olefins and aromatics, and hydrocracking are achieved. All of these reactions are exothermic reactions. In the desulfurization and denitrification reactions, sulfur and nitrogen are split from the sulfur- or nitrogen-containing hydrocarbon rings through aromatic ring saturation and cracking, generating H2S and NH3. The hydrocracking reaction largely retains the hydrocarbon rings. The unsaturated bonds in olefins and aromatics are significantly saturated. The aromatic rings are hydrogenated to form cycloalkanes and then cracked to open the rings.

[0053] In the above method, in step 2), the first oil product is subjected to the first atmospheric fractionation in the first atmospheric fractionation tower (i.e., the hydrocracking atmospheric fractionation tower).

[0054] In the above method, in step 2), when the first oil product is subjected to the first atmospheric fractionation, the top temperature of the first atmospheric fractionation tower is 115°C to 138°C, specifically it can be 115°C to 120°C, 120°C to 130°C, 130°C to 138°C, and preferably it is 120°C to 128°C.

[0055] In the above method, in step 2), the feed temperature of the first atmospheric fractionation is 305°C to 310°C, specifically it can be 305°C to 306°C, 306°C to 309°C, 309°C to 310°C, and preferably it is 306°C to 309°C.

[0056] In the above method, in step 2), when the first oil product is subjected to the first atmospheric fractionation, the bottom temperature of the first atmospheric fractionation tower is 290°C to 298°C, specifically it can be 290°C to 294°C, 294°C to 296°C, 296°C to 298°C, and preferably it is 294°C to 296°C.

[0057] In the above method, in step 2), when the first oil product is subjected to the first atmospheric fractionation, the withdrawal temperature of the side line of the first atmospheric fractionation tower is 115°C to 200°C, specifically it can be 115°C to 170°C, 170°C to 188°C, 188°C to 200°C, and preferably it is 170°C to 188°C.

[0058] The above first atmospheric fractionation is carried out in a plate fractionation tower. The stripping steam is fed from the bottom of the tower, and the material is fed into the first atmospheric fractionation tower from the 8th plate. Under the action of the stripping steam, the light components rise and the heavy components fall, and the gas-liquid two phases are fully contacted on each tower plate, and the product separation is achieved according to different boiling points.

[0059] In the above method, in step 2), the first top component is hydrocracked naphtha. The hydrocracked naphtha is the raw material after being treated by the hydrocracking reaction, and it is the light component oil product obtained at the top of the first atmospheric fractionation tower in the first atmospheric fractionation, generally mainly composed of C5 and C6.

[0060] The above hydrocracked naphtha is withdrawn after being obtained from the top of the atmospheric fractionation column of the hydrocracking unit. Among them, a part of the hydrocracked naphtha is used as a conventional naphtha product, which is cooled and then sent out of the atmospheric fractionation column of the hydrocracking unit, and the other part is returned as reflux to the top of the atmospheric fractionation column of the hydrocracking unit to control the top temperature of the column.

[0061] In the above method, in step 2), the first side stream component is hydrocracked kerosene, which is the raw material after being treated by hydrocracking reaction and is the kerosene component withdrawn from the side stream of the atmospheric fractionation column of the hydrocracking unit, generally composed of C11 - C19. In this preparation method, the above hydrocracked kerosene can be withdrawn from the 27th plate of the side stream of the atmospheric fractionation column of the hydrocracking unit, and the hydrocracked kerosene is taken out of the column as a kerosene product.

[0062] In the above method, in step 2), the first bottom component is the raw material after being treated by hydrocracking reaction, and after the atmospheric fractionation column of the hydrocracking unit separates light components such as hydrocracked naphtha and hydrocracked kerosene, the product obtained at the bottom of the atmospheric fractionation column of the hydrocracking unit.

[0063] In the above method, in step 2), when the first oil product is subjected to the first atmospheric fractionation, the first top component, i.e., hydrocracked naphtha, is obtained at the top of the atmospheric fractionation column, the first side stream component, i.e., hydrocracked kerosene, is obtained from the side stream of the atmospheric fractionation column, and the first bottom component is obtained at the bottom of the atmospheric fractionation column.

[0064] In the above method, in step 2), the nitrogen content in the first bottom component < 2 mg / kg. The nitrogen content in the first bottom component refers to the maximum allowable amount of nitrogen content in the subsequent feed, and the smaller it is in actual production, the better.

[0065] In the above method, in step 2), the sulfur content in the first bottom component < 50 mg / kg. The sulfur content in the first bottom component refers to the maximum allowable amount of sulfur content in the subsequent feed, and the smaller it is in actual production, the better.

[0066] In the above method, in step 3), the isodewaxing reaction is carried out in an isodewaxing reactor.

[0067] In the above method, in step 3), the reaction temperature of the isodewaxing reaction is 333°C - 349°C, specifically it can be 333°C - 335°C, 335°C - 337°C, 337°C - 349°C, and preferably 335°C - 337°C.

[0068] In the above method, in step 3), the reaction pressure of the isodewaxing reaction is 14 MPa to 16 MPa, specifically it can be 14 MPa to 14.5 MPa, 14.5 MPa to 15.5 MPa, 15.5 MPa to 16 MPa. Preferably it is 14.5 to 15.5 MPa.

[0069] The above isodewaxing reaction selects long-chain alkyl hydrocarbons and isomerizes them into isoparaffins to reduce the pour point of the target product and retain the viscosity index of the original paraffins.

[0070] In the above method, in step 3), the post-hydrofining reaction is carried out in a post-hydrofining reactor.

[0071] In the above method, in step 3), the reaction temperature of the post-hydrofining reaction is ≤ 300 °C, preferably 225 °C to 255 °C.

[0072] In the above method, in step 3), the reaction pressure of the post-hydrofining reaction is 14 MPa to 16 MPa, specifically it can be 14 MPa to 14.5 MPa, 14.5 MPa to 15.5 MPa, 15.5 MPa to 16 MPa. Preferably it is 14.5 to 15.5 MPa.

[0073] The above post-hydrofining reaction further promotes the saturation of aromatic compounds under low-temperature and high-pressure conditions.

[0074] In the above method, in step 4), the second oil product is subjected to a second atmospheric distillation in a second atmospheric distillation column (i.e., the isodewaxing atmospheric distillation column).

[0075] In the above method, in step 4), when the second oil product is subjected to the second atmospheric distillation, the top temperature of the second atmospheric distillation column is 115 °C to 128 °C, specifically it can be 115 °C to 118 °C, 118 °C to 125 °C, 125 °C to 138 °C, preferably 118 °C to 125 °C.

[0076] In the above method, in step 4), the feed temperature of the second atmospheric distillation is 300 °C to 320 °C, specifically it can be 300 °C to 308 °C, 308 °C to 313 °C, 313 °C to 320 °C, preferably 308 °C to 313 °C.

[0077] In the above method, in step 4), when the second oil product is subjected to the second atmospheric distillation, the draw temperature of the side line of the second atmospheric distillation column is ≥ 170 °C, preferably 190 °C to 205 °C.

[0078] In the above method, in step 4), when the second oil product undergoes the second atmospheric distillation, the bottom temperature of the second atmospheric distillation column is 299°C to 305°C, specifically it can be 299°C to 300°C, 300°C to 302°C, 302°C to 305°C, and preferably it is 300°C to 302°C.

[0079] The mechanism of action of the above second atmospheric distillation is that in a plate fractionating column, stripping steam is fed from the bottom of the column, and the material is fed into the column from the 8th plate of the second atmospheric distillation column. Under the action of the stripping steam, the light components rise and the heavy components descend, and the gas-liquid two phases are in full contact on each tray, and product separation is achieved according to different boiling points.

[0080] In the above method, in step 4), the second overhead component is isomerized naphtha, generally mainly composed of C5 and C6. After the second overhead component is withdrawn from the top of the isomerization dewaxing atmospheric distillation column, it is divided into two paths. One path is sent out of the isomerization dewaxing atmospheric distillation column as a conventional naphtha product, and the other path is returned as reflux to the inside of the top of the isomerization dewaxing atmospheric distillation column to control the top temperature.

[0081] In the above method, in step 4), the second side stream component is isomerized dewaxed kerosene. The isomerized dewaxed kerosene, as a conventional kerosene component, is generally composed of C11 to C19. In this preparation method, the second side stream component can be withdrawn from the 17th plate of the side stream of the isomerization dewaxing atmospheric distillation column, and after being stripped of light components by a reboiler, it is sent out of the column as a conventional kerosene product.

[0082] In the above method, in step 4), the second bottom component is the oil product obtained after the raw material undergoes hydrocracking reaction, the first atmospheric distillation, and isomerization dewaxing reaction, and after separating light components such as naphtha component and kerosene component in the isomerization dewaxing atmospheric distillation column of the second atmospheric distillation.

[0083] In the above method, in step 5), the vacuum distillation is carried out in a vacuum distillation column (i.e., an isomerization dewaxing vacuum distillation column).

[0084] In the above method, in step 5), the feed temperature of the vacuum distillation is 319°C to 321°C, specifically it can be 319 to 319.5°C, 319.5 to 320.5°C, 320.5 to 321°C, and preferably it is 319.5 to 320.5°C.

[0085] The vacuum distillation column for the above vacuum distillation is a packed column and can be divided into 7 layers of packing. Stripping steam is fed from the bottom of the column, and the material is fed between the first and second packing beds. Under vacuum conditions, the gas-liquid two phases are in full contact on the packing of each bed, the light components rise layer by layer, and the heavy components descend layer by layer to achieve fine separation of the products.

[0086] In the above method, in step 5), when the second bottom component is subjected to vacuum fractionation, the first light component is obtained at the top of the vacuum fractionation column, the light lubricating oil is obtained from the first side line of the vacuum fractionation column, the medium lubricating oil is obtained from the second side line of the vacuum fractionation column, the heavy lubricating oil is obtained from the third side line of the vacuum fractionation column, and the bottoms lubricating oil is obtained at the bottom of the vacuum fractionation column.

[0087] The first side line of the above-mentioned vacuum fractionation column is located between the fifth packing bed layer and the sixth packing bed layer in the vacuum fractionation column, the second side line is located between the fourth packing bed layer and the fifth packing bed layer in the vacuum fractionation column, and the third side line is located between the second packing bed layer and the third packing bed layer in the vacuum fractionation column. The above-mentioned first packing bed layer to the seventh packing bed layer are arranged in sequence from the bottom to the top in the vacuum fractionation column.

[0088] In the above method, in step 5), when the second bottom component is subjected to vacuum fractionation, the pressure at the top of the vacuum fractionation column is -101 kPa to -90 kPa, specifically it can be -101 kPa to -98 kPa, -98 kPa to -94 kPa, -94 kPa to -90 kPa, and preferably it is -98 kPa to -94 kPa.

[0089] In the above method, in step 5), when the second bottom component is subjected to vacuum fractionation, the temperature at the top of the vacuum fractionation column is 85 °C to 98 °C, specifically it can be 85 °C to 91 °C, 91 °C to 96 °C, 96 °C to 98 °C, and preferably it is 91 °C to 96 °C.

[0090] In the above method, in step 5), when the second bottom component is subjected to vacuum fractionation, the draw-off temperature of the first side line of the vacuum fractionation column > 190 °C, preferably 210 °C to 220 °C.

[0091] In the above method, in step 5), when the second bottom component is subjected to vacuum fractionation, the draw-off temperature of the second side line of the vacuum fractionation column > 240 °C, preferably 245 °C to 255 °C.

[0092] In the above method, in step 5), when the second bottom component is subjected to vacuum fractionation, the draw-off temperature of the third side line of the vacuum fractionation column ≥ 275 °C, preferably 278 °C to 282 °C.

[0093] In the above method, in step 5), when the second bottom component is subjected to vacuum fractionation, there is no limit requirement for the temperature at the bottom of the vacuum fractionation column.

[0094] In the above method, in step 5), the first light component is the overhead diesel. After the first light component is drawn from the top of the vacuum fractionation column, it is divided into two paths. One path is sent out as diesel product, and the other path is returned as reflux to the top of the vacuum fractionation column to control the top temperature.

[0095] In the above method, in step 5), the amount of the first light component discharged from the device is 2-3 t / h, specifically it can be 2-2.2 t / h, 2.2-2.7 t / h, 2.7-3.0 t / h, and preferably 2.2 t / h-2.7 t / h.

[0096] In the above method, in step 5), the light lubricating oil is a product medium drawn from the first side line between the fifth packing bed layer and the sixth packing bed layer in the vacuum fractionating tower. After being steam-stripped by the side line packing tower, the light components return to the vacuum fractionating tower, and the bottom components are discharged from the vacuum fractionating tower as lubricating oil products. The kinematic viscosity of the above light lubricating oil at 40 °C is ≥7 mm 2 / s and <12 mm 2 / s.

[0097] In the above method, in step 5), the medium lubricating oil is a product medium drawn from the second side line between the fourth packing bed layer and the fifth packing bed layer in the vacuum fractionating tower. After being steam-stripped by the side line packing tower, the light components return to the vacuum fractionating tower, and the bottom components are discharged from the vacuum fractionating tower as lubricating oil products. The kinematic viscosity of the above medium lubricating oil at 40 °C is ≥12 mm 2 / s and <25 mm 2 / s.

[0098] In the above method, in step 5), the bottom lubricating oil is a product medium drawn from the bottom of the vacuum fractionating tower, and after being air-cooled, it is discharged from the vacuum fractionating tower as a lubricating oil product. The kinematic viscosity of the above bottom lubricating oil at 40 °C is ≥35 mm 2 / s and ≤100 mm 2 / s.

[0099] In the above method, in step 5), the heavy lubricating oil is a product medium drawn from the third side line between the second packing bed layer and the third packing bed layer in the vacuum fractionating tower. The kinematic viscosity of the above heavy lubricating oil at 40 °C is ≥25 mm 2 / s and <35 mm 2 / s.

[0100] In the above method, in step 6), the first part of the heavy lubricating oil returns to step 5) as a thermal reflux.

[0101] In one embodiment, the first part of the heavy lubricating oil returns to the vacuum fractionating tower between the second packing bed layer and the third packing bed layer of the vacuum fractionating tower, and the return position of the first part of the heavy lubricating oil is lower than the extraction position of the heavy lubricating oil from the vacuum fractionating tower.

[0102] In one embodiment, the thermal reflux amount of the first part of the heavy lubricating oil as a thermal reflux is ≤10 t / h, and preferably 3.2 t / h-3.8 t / h.

[0103] In the above method, in step 6), the second part of the heavy lubricating oil returns to step 5) as a cold reflux.

[0104] In one embodiment, the second part of the heavy lubricating oil is cooled by a heat exchanger and then returns to the vacuum fractionating column.

[0105] In a preferred embodiment, the temperature after cooling is 210°C to 221°C, preferably 214°C to 218°C.

[0106] In one embodiment, the second part of the heavy lubricating oil returns to the vacuum fractionating column between the third packing bed layer and the fourth packing bed layer of the vacuum fractionating column.

[0107] In one embodiment, the cold reflux flow rate of the second part of the heavy lubricating oil as a cold reflux is ≥17 t / h, preferably 19.5 t / h to 21 t / h.

[0108] In the above method, in step 6), the mass ratio among the first part, the second part, and the third part of the heavy lubricating oil is 1:5.5 - 6.5:1.5 - 2.5, preferably 1:5.8:2.

[0109] In the above method, in step 6), the third part of the heavy lubricating oil is steam - stripped in a stripping column. The stripping column is a side - line packed column. Under the action of steam stripping, the light components in the third part of the heavy lubricating oil are further volatilized, return to the vacuum fractionating column from the top of the stripping column, improving the quality of the third part of the heavy lubricating oil, while the high - viscosity - index base oil is obtained from the bottom of the stripping column.

[0110] In the above method, in step 6), the steam flow rate for steam stripping is 0.1 - 0.5 t / h, specifically it can be 0.1 - 0.2 t / h, 0.2 - 0.4 t / h, 0.4 - 0.5 t / h, preferably 0.2 - 0.4 t / h.

[0111] In the above method, in step 6), the temperature for steam stripping is 190°C to 205°C, specifically it can be 190°C - 195°C, 195°C - 199°C, 199°C - 205°C, preferably 195°C - 199°C.

[0112] In the above method, in step 6), the steam pressure for steam stripping is ≥0.8 MPa, preferably 1.0 MPa.

[0113] In the above method, in step 6), the second light component is obtained at the top of the stripping column and returns to step 5).

[0114] The second light component is an oil and gas component that volatilizes spontaneously under the action of stripping steam, generally diesel oil.

[0115] In one embodiment, in step 6), the second light component returns to the vacuum fractionating tower between the third packing bed and the fourth packing bed of the vacuum fractionating tower, and the return position of the second light component is higher than the return position of the second part of the heavy lubricating oil as the cold reflux.

[0116] In one embodiment, in step 6), the temperature at which the second light component returns to the vacuum fractionating tower is ≥255 °C, preferably 258 °C - 274 °C.

[0117] In the above method, in step 6), the high-viscosity index base oil is obtained at the bottom of the stripping tower.

[0118] The second aspect of the present invention provides a high-viscosity index base oil obtained by the above method.

[0119] Table 1

[0120]

[0121] In the above base oil, the high-viscosity index base oil meets the API HVIⅢ4 standard. Specifically, the content of the API HVIⅢ4 standard is shown in Table 1 above. Among them, the high viscosity index of the base oil means that the viscosity index of the base oil ≥120.

[0122] The third aspect of the present invention provides a preparation system for a high-viscosity index base oil, as Figure 1 shown, a hydrocracking reactor, a hydrocracking atmospheric fractionating tower, an isodewaxing reactor, a post-hydrofining reactor, an isodewaxing atmospheric fractionating tower, an isodewaxing vacuum fractionating tower, and a stripping tower are sequentially provided along the raw material input direction, and the hydrocracking reactor, the hydrocracking atmospheric fractionating tower, the isodewaxing reactor, the post-hydrofining reactor, the isodewaxing atmospheric fractionating tower, the isodewaxing vacuum fractionating tower, and the stripping tower are sequentially connected by pipelines.

[0123] The above hydrocracking reactor, hydrocracking atmospheric fractionating tower, isodewaxing reactor, post-hydrofining reactor, isodewaxing atmospheric fractionating tower, isodewaxing vacuum fractionating tower, and stripping tower are all reaction devices commonly used in the art.

[0124] In the above preparation system, as Figure 1 shown, the bottom of the hydrocracking reactor is connected to the hydrocracking atmospheric fractionating tower through a pipeline. After the bottom product of the hydrocracking reactor is separated into water, gas, and oil phases, the oil-phase medium is transported to the hydrocracking atmospheric fractionating tower through a pipeline.

[0125] In the above preparation system, as Figure 1As shown, the bottom of the hydrocracking atmospheric fractionating column is connected to the isodewaxing reactor through a pipeline. The bottom product of the hydrocracking atmospheric fractionating column is transported to the isodewaxing reactor through pipelines and other static and dynamic equipment.

[0126] In the above preparation system, as Figure 1 shown, the bottom of the isodewaxing reactor is connected to the top of the post-hydrofining reactor through a pipeline.

[0127] In the above preparation system, as Figure 1 shown, the bottom of the post-hydrofining reactor is connected to the isodewaxing atmospheric fractionating column through a pipeline. After the bottom product of the post-hydrofining reactor is separated into water, gas, and oil phases, the oil-phase medium is transported to the isodewaxing atmospheric fractionating column through a pipeline.

[0128] In the above preparation system, as Figure 1 shown, the bottom of the isodewaxing atmospheric fractionating column is connected to the isodewaxing vacuum fractionating column through a pipeline. The bottom product of the isodewaxing atmospheric fractionating column is transported to the isodewaxing vacuum fractionating column through pipelines and other static and dynamic equipment.

[0129] In the above preparation system, the isodewaxing vacuum fractionating column is provided with a first packing bed to a seventh packing bed in sequence from bottom to top.

[0130] In the above preparation system, as Figure 1 shown, the third side line of the isodewaxing vacuum fractionating column is connected to the stripping column through a pipeline.

[0131] The following specific examples illustrate the implementation modes of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0132] In the following examples, the general indicators of the mixed material of vacuum gas oil from the fourth side stream of distillation, hydrocracking tail oil, and underflow of ketone-benzene dewaxing are shown in Table 2 below. Properties of the mixed material of vacuum gas oil from the fourth side stream of distillation, hydrocracking tail oil, and underflow of ketone-benzene dewaxing: boiling range is 320°C to 460°C, wax content is 20wt% to 55wt%, water content ≤ 0.03wt%, pour point is 32°C to 45°C.

[0133] Table 2

[0134] Index Raw material Moisture (mixed), %(mass fraction) 0.03 <![CDATA[Kinematic viscosity (100 °C), mm 2 / s]]> 7.124 Viscosity index 102 Pour point, °C 48 Initial boiling point, °C 343 50% recovery temperature, °C 407 Final boiling point, °C 465 Wax content, %(mass fraction) 25.01 <![CDATA[Density (20 °C), kg / m 3 > 893.1 Sulfur content, %(mass fraction) 0.254

[0135] Example 1

[0136] The preparation process of high viscosity index base oil No. 1 is as follows:

[0137] 1) The distilled four-line wax oil, hydrocracking tail oil, and ketone benzene wax lower oil are fully mixed in a mass ratio of 1:1:1, and filtered after heat exchange to remove solid particles and impurities larger than 25 μm. Then, the mixture is mixed with circulating hydrogen, heated, and then introduced into a hydrocracking reactor for hydrocracking reaction to obtain a first oil product.

[0138] Among them, the total feed amount is 33t / h, and the distillation of four-line wax oil, hydrocracking tail oil, and ketone benzene wax oil are all 11t / h. The material properties of the mixture of distillation of four-line wax oil, hydrocracking tail oil, and ketone benzene wax oil are as follows: nitrogen content is 267.96mg / kg, distillation range is 340℃~455℃, distillation range width is ≥80℃, wax content is 24.66%, moisture content is ≤0.03wt%, pour point is 42℃, kinematic viscosity (100℃) is 5.135mm 2 / s.

[0139] The temperature of the hydrocracking reaction is 379°C, the pressure of the hydrocracking reaction is 14.60MPa, and the concentration of hydrogen sulfide in the circulating hydrogen participating in the hydrocracking reaction is 500ppm.

[0140] 2) The first oil product enters a hydrocracking atmospheric fractionation tower for a first atmospheric fractionation, and the hydrocracking naphtha as a first tower top component, the hydrocracking kerosene component as a first side line component, and the first tower bottom component obtained at the tower bottom are cut out.

[0141] Among them, the feed temperature of the hydrocracking atmospheric distillation tower is 309°C, the top temperature is 121°C, the bottom temperature is 295°C, and the side line extraction temperature is 180°C; the nitrogen content of the distillation tower bottom product is controlled at <2mg / kg, and the sulfur content is controlled at <50mg / kg.

[0142] 3) The first bottom component is input into an isodewaxing reactor for isodewaxing reaction, and the long carbon chain of the oil product is isomerized to reduce the pour point; then the first bottom component is input into a hydrogenation refining reactor for hydrogenation refining reaction, and under the low temperature and high pressure conditions of hydrogenation refining, a large degree of saturation of aromatics is achieved to obtain a second oil product.

[0143] Among them, the temperature of the isodewaxing reaction is 336°C, the temperature of the refining reaction after hydrogenation is 237°C, and the pressure of the isodewaxing reaction and the refining reaction after hydrogenation is 14.56MPa.

[0144] 4) The second oil product is input into the isomeric dewaxing atmospheric distillation tower for a second atmospheric distillation, and the second tower top component and the second side line component are further clearly cut according to the distillation range to obtain the second tower bottom component at the bottom of the tower.

[0145] Among them, the tower top temperature is 120°C, the feed temperature is 310°C, the extraction temperature of the side line component is 199°C, and the tower bottom temperature is 301°C.

[0146] 5) Feed the second bottom component into the isodewaxing vacuum fractionating column for vacuum fractionation. Diesel oil, which is the first light component, is obtained at the top of the column. Light lubricating oil is obtained at the first side draw. Medium lubricating oil is obtained at the second side draw. Heavy lubricating oil is obtained at the third side draw. Bottom lubricating oil is obtained at the bottom of the column.

[0147] Among them, the feed temperature for vacuum fractionation is 319.5 °C, the pressure at the top of the vacuum fractionating column is -96 kPa, the withdrawal rate of diesel oil at the top of the column is 2.6 t / h, the temperature at the top of the vacuum fractionating column is 93 °C, the draw temperature of the first side draw is 215 °C, the draw temperature of the second side draw is 250 °C, the draw temperature of the third side draw, i.e., the heavy lubricating oil side draw, is 280.8 °C, and there is no restricted requirement for the temperature at the bottom of the column.

[0148] 6) Divide the heavy lubricating oil into the first part of heavy lubricating oil, the second part of heavy lubricating oil, and the third part of heavy lubricating oil. The mass ratio among the first part of heavy lubricating oil, the second part of heavy lubricating oil, and the third part of heavy lubricating oil is 1:5.8:2. The first part of heavy lubricating oil is returned to the vacuum fractionating column as a hot reflux, and the hot reflux rate is 3.7 t / h. The second part of heavy lubricating oil is returned to the vacuum fractionating column as a cold reflux after being cooled by a heat exchanger, and the temperature after cooling is 216 °C, and the cold reflux rate is 19.8 t / h. The third part of heavy lubricating oil is subjected to steam stripping in a stripping column. The second light component is obtained and returned to the vacuum fractionating column from the top of the stripping column under the action of steam stripping. High-viscosity index base oil No. 1 meeting the API HVIⅢ4 standard is produced at the bottom of the stripping column. Among them, the steam flow rate for steam stripping is 0.25 t / h, the temperature for steam stripping is 199 °C, the steam pressure for steam stripping is 1.0 MPa, the temperature at which the second light component returns to the vacuum fractionating column is 261.8 °C, and the production rate of high-viscosity index base oil is 6.5 t / h.

[0149] The above hydrogenation process can process low-nitrogen and low-sulfur raw materials, and the process runs stably. Finally, high-viscosity index base oil meeting the API HVIⅢ4 standard with excellent viscosity, viscosity index, evaporation loss, and oxidation stability is obtained. The specific performance data are shown in Table 3 below.

[0150] Example 2

[0151] The preparation process of high-viscosity index base oil No. 2 is as follows:

[0152] 1) Fully mix the distilled reduced fourth-line wax oil, hydrocracking tail oil, and ketone-benzene wax bottom oil in a mass ratio of 1:1:1. After heat exchange, filter to remove solid particles and impurities larger than 25 μm. Then mix with recycle hydrogen, heat, and enter the hydrocracking reactor for hydrocracking reaction to obtain the first oil product.

[0153] Among them, the total feed rate is 35 t / h, and the vacuum gas oil from the fourth side stream of distillation, the tail oil of hydrocracking, and the underflow of ketone-benzene dewaxing are all 11.67 t / h. The properties of the mixture of the vacuum gas oil from the fourth side stream of distillation, the tail oil of hydrocracking, and the underflow of ketone-benzene dewaxing: nitrogen content is 328.96 mg / kg, boiling range is 335°C to 452°C, boiling range width ≥ 80°C, wax content is 23.08%, moisture content is ≤ 0.03 wt%, pour point is 45°C, and kinematic viscosity (at 100°C) is 4.983 mm 2 / s.

[0154] The temperature of the hydrocracking reaction is 380°C, and the pressure of the hydrocracking reaction is 15.5 MPa; the hydrogen sulfide concentration in the recycled hydrogen participating in the hydrocracking reaction is 800 ppm.

[0155] 2) Feed the first oil product into the atmospheric fractionating tower of hydrocracking for the first atmospheric fractionation to cut out hydrocracked naphtha as the first top component, hydrocracked kerosene component as the first side stream component, and the first bottom component obtained at the bottom of the tower.

[0156] Among them, the feed temperature of the atmospheric fractionating tower of hydrocracking is 310°C, the top temperature is 125°C; the bottom temperature is 296°C, and the draw temperature of the side stream is 175°C; the nitrogen content of the product at the bottom of the fractionating tower is controlled at < 2 mg / kg, and the sulfur content is controlled at < 50 mg / kg.

[0157] 3) Input the first bottom component into the isodewaxing reactor for isodewaxing reaction to conduct isomerization reaction of long carbon chains for the oil product to reduce the pour point; then input it into the post-hydrofining reactor for post-hydrofining reaction. Under the conditions of low temperature and high pressure in post-hydrofining, a large amount of aromatics saturation is achieved to obtain the second oil product.

[0158] Among them, the temperature of the isodewaxing reaction is 337°C, the temperature of the post-hydrofining reaction is 238°C, and the pressure of the isodewaxing reaction and the post-hydrofining reaction is 14.52 MPa.

[0159] 4) Input the second oil product into the atmospheric fractionating tower of isodewaxing for the second atmospheric fractionation, and conduct clear cutting on the second top component and the second side stream component according to the boiling range, and obtain the second bottom component at the bottom of the tower.

[0160] Among them, the top temperature is 125°C; the feed temperature is 312°C, the draw temperature of the side stream component is 201°C, and the bottom temperature is 302°C.

[0161] 5) Input the second bottom component into the vacuum fractionating tower of isodewaxing for vacuum fractionation to obtain diesel as the first light component at the top of the tower, light lubricating oil at the first side stream, medium lubricating oil at the second side stream, heavy lubricating oil at the third side stream, and bottom lubricating oil at the bottom of the tower.

[0162] Among them, the feed temperature of vacuum fractionation is 320.3 °C, the pressure at the top of the vacuum fractionation column is -94 kPa, the output of diesel oil from the top of the column is 2.5 t / h, the temperature at the top of the vacuum fractionation column is 95 °C, the draw temperature of the first side line is 217 °C, the draw temperature of the second side line is 252 °C, the draw temperature of the third side line, i.e., the heavy lubricating oil side line, is 281.5 °C, and there is no limit requirement for the temperature at the bottom of the column.

[0163] 6) The heavy lubricating oil is divided into the first part of the heavy lubricating oil, the second part of the heavy lubricating oil, and the third part of the heavy lubricating oil. The mass ratio among the first part of the heavy lubricating oil, the second part of the heavy lubricating oil, and the third part of the heavy lubricating oil is 1:5.8:2. The first part of the heavy lubricating oil returns to the vacuum fractionation column as a hot reflux, and the hot reflux rate is 3.5 t / h; the second part of the heavy lubricating oil returns to the vacuum fractionation column as a cold reflux after being cooled by a heat exchanger, and the temperature after cooling is 218 °C, and the cold reflux rate is 20.9 t / h; the third part of the heavy lubricating oil is steam stripped in a stripping column. The second light component returns from the top of the stripping column to the vacuum fractionation column under the action of steam stripping, and high-viscosity index base oil No. 2 meeting the API HVIⅢ4 standard is produced at the bottom of the stripping column. Among them, the steam flow rate for steam stripping is 0.25 t / h, the temperature for steam stripping is 198 °C, the steam pressure for steam stripping is 1.0 MPa, the temperature at which the second light component returns to the vacuum fractionation column is 265.3 °C, and the output of high-viscosity index base oil is 7.01 t / h.

[0164] The above hydrogenation process can process low-nitrogen and low-sulfur raw materials, and the process runs stably. Finally, high-viscosity index base oil meeting the API HVIⅢ4 standard with excellent viscosity, viscosity index, evaporation loss, and oxidation stability is obtained. The specific performance data are shown in Table 3 below.

[0165] Example 3

[0166] The preparation process of high-viscosity index base oil No. 2 is as follows:

[0167] 1) The distilled reduced fourth-line wax oil, hydrocracked tail oil, and ketone benzene wax bottom oil are fully mixed according to the mass ratio of 1:1:1, filtered after heat exchange, and solid particles and impurities larger than 25 μm are filtered out. Then it is mixed with recycled hydrogen, heated, and enters a hydrocracking reactor for hydrocracking reaction to obtain the first oil product.

[0168] Among them, the total feed rate is 36 t / h, and the vacuum distillation reduced fourth-line wax oil, hydrocracked tail oil, and ketone benzene wax bottom oil are all 12 t / h each. The properties of the mixture of vacuum distillation reduced fourth-line wax oil, hydrocracked tail oil, and ketone benzene wax bottom oil: nitrogen content is 394.37 mg / kg, distillation range is 330 °C to 450 °C, distillation range width ≥ 80 °C, wax content is 32.65%, water content is ≤ 0.03 wt%, pour point is 45 °C, kinematic viscosity (100 °C) is 4.753 mm 2 / s.

[0169] The temperature of the hydrocracking reaction is 377.8 °C, and the pressure of the hydrocracking reaction is 15.4 MPa; the hydrogen sulfide concentration in the recycled hydrogen participating in the hydrocracking reaction is 500 ppm.

[0170] 2) Feed the first oil product into the atmospheric fractionating tower of hydrocracking for the first atmospheric fractionation to cut out hydrocracked naphtha as the first top component, hydrocracked kerosene component as the first side-line component, and the first bottom component obtained at the bottom of the tower.

[0171] Among them, the feed temperature of the atmospheric fractionating tower of hydrocracking is 306.2 °C, the top temperature is 120 °C; the bottom temperature is 294 °C, and the extraction temperature of the side line is 182 °C; the nitrogen content of the fractionation tower bottom product is controlled at < 2 mg / kg, and the sulfur content is controlled at < 50 mg / kg.

[0172] 3) Input the first bottom component into the isodewaxing reactor for isodewaxing reaction to carry out isomerization reaction of long carbon chains for the oil product to reduce the pour point; then input it into the post-hydrofining reactor for post-hydrofining reaction, and under the conditions of low temperature and high pressure in post-hydrofining, achieve a large degree of saturation of aromatics to obtain the second oil product.

[0173] Among them, the temperature of the isodewaxing reaction is 336.5 °C, the temperature of the post-hydrofining reaction is 236 °C, and the pressure of the isodewaxing reaction and the post-hydrofining reaction is 14.82 MPa.

[0174] 4) Input the second oil product into the atmospheric fractionating tower of isodewaxing for the second atmospheric fractionation, and further clearly cut the second top component and the second side-line component according to the distillation range, and obtain the second bottom component at the bottom of the tower.

[0175] Among them, the top temperature is 124 °C; the feed temperature is 309 °C, the extraction temperature of the side-line component is 203 °C, and the bottom temperature is 300 °C.

[0176] 5) Input the second bottom component into the vacuum fractionating tower of isodewaxing for vacuum fractionation to obtain diesel as the first light component at the top of the tower, light lubricating oil at the first side line, medium lubricating oil at the second side line, heavy lubricating oil at the third side line, and bottom lubricating oil at the bottom of the tower.

[0177] Among them, the feed temperature of vacuum fractionation is 319.5 °C, the pressure at the top of the vacuum fractionation column is -98 kPa, the output of diesel oil at the top of the column is 2.2 t / h, the temperature at the top of the vacuum fractionation column is 94 °C, the draw temperature of the first side line is 218 °C, the draw temperature of the second side line is 248 °C, the draw temperature of the third side line, i.e., the heavy lubricating oil side line, is 280.2 °C, and there is no limit requirement for the temperature at the bottom of the column.

[0178] 6) The heavy lubricating oil is divided into the first part of heavy lubricating oil, the second part of heavy lubricating oil, and the third part of heavy lubricating oil. The mass ratio among the first part of heavy lubricating oil, the second part of heavy lubricating oil, and the third part of heavy lubricating oil is 1:5.8:2. The first part of heavy lubricating oil is returned to the vacuum fractionation column as a hot reflux, and the hot reflux amount is 3.6 t / h; the second part of heavy lubricating oil is returned to the vacuum fractionation column as a cold reflux after being cooled by a heat exchanger, and the temperature after cooling is 215 °C, and the cold reflux amount is 20.8 t / h; the third part of heavy lubricating oil is steam-stripped in a stripping column. The second light component returns to the vacuum fractionation column from the top of the stripping column under the action of steam stripping, and high-viscosity index base oil No. 3 meeting the API HVIⅢ4 standard is produced at the bottom of the stripping column. Among them, the steam amount for steam stripping is 0.3 t / h, the temperature for steam stripping is 199 °C, the steam pressure for steam stripping is 1.0 MPa, the temperature at which the second light component returns to the vacuum fractionation column is 262.1 °C, and the output of high-viscosity index base oil is 7.5 t / h.

[0179] The above hydrogenation process can process low-nitrogen and low-sulfur raw materials, and the process runs stably. Finally, high-viscosity index base oil meeting the API HVIⅢ4 standard with excellent viscosity, viscosity index, evaporation loss, and oxidation stability is obtained. The specific performance data are shown in Table 3 below.

[0180] Table 3

[0181] HVIⅢ4 base oil index Example 1 Example 2 Example 3 <![CDATA[Kinematic viscosity (100 °C), mm 2 / s]]> 4.392 4.285 4.410 Viscosity index 121 121 122 Sulfur content, %(mass fraction) 0.0001 0.0001 0.0001 Saturated hydrocarbon, %(mass fraction) 99.82 99.90 99.91 Flash point, °C 214 218 224 Pour point, °C -18 -18 -18 Evaporation loss, %(mass fraction) 13.5 12.0 11.7 Oxidation stability, rotating oxygen bomb method (150 °C), min 337 338 338

[0182] Comparative example

[0183] The base oil meeting the APIⅡ is obtained according to the existing process. Compared with the high-viscosity index base oil No. 3 obtained in Example 3 above, the selling price of the base oil meeting the APIⅡ is about 6,200 yuan / ton (excluding tax), while the average selling price of the high-viscosity index base oil No. 3 in the same period is 8,000 yuan / ton (excluding tax). When the sales volume is 280 tons, the sales amount of the high-viscosity index base oil No. 3 is 2,240,000 yuan. Compared with the base oil meeting the APIⅡ obtained in the comparative example, the economic benefit is increased by 504,000 yuan, and the marginal profit is increased by 1,800 yuan / ton, significantly increasing the economic benefit.

[0184] The above are only the preferred embodiments of the present invention, and do not impose any formal or substantial limitations on the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the method of the present invention, several improvements and supplements can still be made, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any equivalent changes such as slight modifications, decorations and evolutions made by those who are familiar with the technology in this field without departing from the spirit and scope of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the substantial technology of the present invention still fall within the scope of the technical solutions of the present invention.

Claims

1. A method for preparing a high viscosity index base oil, comprising the following steps: 1) Mixing vacuum gas oil from the fourth side stream of distillation, hydrocracking tail oil, and slack wax from ketone-benzene dewaxing, and then carrying out hydrocracking reaction to obtain a first oil product; 2) Conducting the first atmospheric distillation on the first oil product to separately obtain a first top component, a first side stream component, and a first bottom component; 3) Subject the first bottom component to isodewaxing reaction and hydrofinishing reaction to obtain a second oil product; 4) Conduct a second atmospheric distillation on the second oil product to separately obtain a second top component, a second side stream component, and a second bottom component; 5) Conduct a vacuum distillation on the second bottom component to separately obtain a first light component, light lubricating oil, medium lubricating oil, heavy lubricating oil, and bottom vacuum lubricating oil; 6) Divide the heavy lubricating oil into a first part, a second part, and a third part of the heavy lubricating oil, and subject the third part of the heavy lubricating oil to steam stripping to obtain a second light component and a high viscosity index base oil.

2. The method for preparing a high viscosity index base oil according to claim 1, wherein, In step 1), any one or more of the following conditions are included: A1) The nitrogen content in the mixture of the distilled vacuum gas oil, hydrocracking tail oil, and ketone benzene wax tail oil is ≤ 1700 mg / kg; A2) In the mixture of the distilled vacuum gas oil, hydrocracking tail oil, and ketone benzene wax tail oil, the distillation range is 320°C to 460°C, and the distillation range width ≥ 80°C; A3) The wax content in the mixture of the distilled vacuum gas oil, hydrocracking tail oil, and ketone benzene wax tail oil is 20 wt% to 55 wt%; A4) The water content in the mixture of the distilled vacuum gas oil, hydrocracking tail oil, and ketone benzene wax tail oil is ≤ 0.03 wt%; A5) The pour point of the mixture of the distilled vacuum gas oil, hydrocracking tail oil, and ketone benzene wax tail oil is 32°C to 45°C; A6) The kinematic viscosity of the material after mixing the vacuum residue hydrotreated fourth side stream wax oil, hydrocracked tail oil, and ketone-benzene dewaxing underflow is 4.5 - 5.2 mm 2 / s at 100 °C; A7) The mass ratio of the distilled vacuum gas oil, hydrocracking tail oil, and ketone benzene wax tail oil in the mixture is 0.8 to 1.2:0.8 to 1.2:0.8 to 1.2; A8) After mixing the distilled vacuum gas oil, hydrocracking tail oil, and ketone benzene wax tail oil, it needs to be filtered to remove solid particles and impurities. Preferably, the particle size of the filtered solid particles and impurities > 25 μm; A9) The hydrogen sulfide concentration in the recycled hydrogen introduced into the hydrocracking reaction is ≤ 1500 ppm; A10) The temperature of the hydrocracking reaction is 370°C to 380°C; A11) The pressure of the hydrocracking reaction is 14 MPa to 16 MPa.

3. The method for preparing a high viscosity index base oil according to claim 1, wherein, In step 2), any one or more of the following conditions are included: B1) Conduct the first atmospheric distillation of the first oil product in the first atmospheric distillation column; B2) When the first oil product is subjected to the first atmospheric distillation, the top temperature of the first atmospheric distillation column is 115°C to 138°C; B3) The feed temperature of the first atmospheric distillation is 305°C to 310°C; B4) When the first oil product is subjected to the first atmospheric distillation, the bottom temperature of the first atmospheric distillation column is 290°C to 298°C; B5) When the first oil product is subjected to the first atmospheric distillation, the draw temperature of the side stream of the first atmospheric distillation column is 115°C to 200°C; B6) The nitrogen content in the first bottom component < 2 mg / kg; B7) The sulfur content in the first bottom component < 50 mg / kg.

4. The method for preparing a high viscosity index base oil according to claim 1, wherein, In step 3), any one or more of the following conditions are included: C1) The isodewaxing reaction is carried out in an isodewaxing reactor; C2) The reaction temperature of the isodewaxing reaction is 333°C to 349°C; C3) The reaction pressure of the isomerization dewaxing reaction is 14 MPa to 16 MPa; C4) The post-hydrogenation refining reaction is carried out in a post-hydrogenation refining reactor; C5) The reaction temperature of the post-hydrogenation refining reaction is ≤ 300 °C; C6) The reaction pressure of the post-hydrogenation refining reaction is 14 MPa to 16 MPa.

5. The preparation method of the high viscosity index base oil according to claim 1, characterized in that, In step 4), any one or more of the following conditions are included: D1) The second oil product undergoes a second atmospheric distillation in a second atmospheric distillation column; D2) When the second oil product undergoes the second atmospheric distillation, the top temperature of the second atmospheric distillation column is 115 °C to 128 °C; D3) The feed temperature of the second atmospheric distillation is 300 °C to 320 °C; D4) When the second oil product undergoes the second atmospheric distillation, the draw temperature of the side line of the second atmospheric distillation column is ≥ 170 °C; D5) When the second oil product undergoes the second atmospheric distillation, the bottom temperature of the second atmospheric distillation column is 299 °C to 305 °C.

6. The preparation method of the high viscosity index base oil according to claim 1, characterized in that, In step 5), any one or more of the following conditions are included: E1) The vacuum distillation is carried out in a vacuum distillation column; E2) The feed temperature of the vacuum distillation is 319 °C to 321 °C; E3) When the second bottom component undergoes vacuum distillation, the first light component is obtained at the top of the vacuum distillation column, the light lubricating oil is obtained at the first side line of the vacuum distillation column, the medium lubricating oil is obtained at the second side line of the vacuum distillation column, the heavy lubricating oil is obtained at the third side line of the vacuum distillation column, and the bottom lubricating oil is obtained at the bottom of the vacuum distillation column; E4) When the second bottom component undergoes vacuum distillation, the pressure at the top of the vacuum distillation column is -101 kPa to -90 kPa; E5) When the second bottom component undergoes vacuum distillation, the top temperature of the vacuum distillation column is 85 °C to 98 °C; E6) When the second bottom component undergoes vacuum distillation, the draw temperature of the first side line of the vacuum distillation column is > 190 °C; E7) When the second bottom component undergoes vacuum distillation, the draw temperature of the second side line of the vacuum distillation column is > 240 °C; E8) When the second bottom component undergoes vacuum distillation, the draw temperature of the third side line of the vacuum distillation column is ≥ 275 °C; E9) The discharge rate of the first light component is 2 to 3 t / h.

7. The preparation method of the high viscosity index base oil according to claim 1, characterized in that, In step 6), any one or more of the following conditions are included: F1) The first part of the heavy lubricating oil is returned as a hot reflux to step 5); F2) The second part of the heavy lubricating oil is returned as a cold reflux to step 5); F3) The mass ratio among the first part, the second part, and the third part of the heavy lubricating oil is 1:5.5 to 6.5:1.5 to 2.5; F4) The third part of the heavy lubricating oil undergoes steam stripping in a stripping column; F5) The steam flow rate of the steam stripping is 0.1 to 0.5 t / h; F6) The temperature of the steam stripping is 190 °C to 205 °C; F7) The steam pressure of the steam stripping is ≥ 0.8 MPa; F8) The second light component is obtained at the top of the stripping column and returned to step 5); F9) The high viscosity index base oil is obtained at the bottom of the stripping column.

8. The preparation method of the high viscosity index base oil according to claim 7, characterized in that, It also includes any one or more of the following conditions: F11) In F1), the heat reflux amount of the first part of the heavy lubricating oil as heat reflux ≤ 10 t / h; F21) In F2), the second part of the heavy lubricating oil returns to the vacuum fractionating tower after being cooled by a heat exchanger; preferably, the temperature after cooling is 210°C to 221°C; F22) In F2), the cold reflux amount of the second part of the heavy lubricating oil as cold reflux ≥ 17 t / h; F81) In F8), the temperature at which the second light component returns to the vacuum fractionating tower ≥ 255°C.

9. A high viscosity index base oil obtained by the preparation method of the high viscosity index base oil according to any one of claims 1-8.

10. A preparation system for a high viscosity index base oil, characterized in that, A hydrocracking reactor (1), a hydrocracking atmospheric fractionating tower (2), an isodewaxing reactor (3), a post-hydrofining reactor (4), an isodewaxing atmospheric fractionating tower (5), an isodewaxing vacuum fractionating tower (6), and a stripping tower (7) are successively arranged along the raw material input direction, and the hydrocracking reactor (1), the hydrocracking atmospheric fractionating tower (2), the isodewaxing reactor (3), the post-hydrofining reactor (4), the isodewaxing atmospheric fractionating tower (5), the isodewaxing vacuum fractionating tower (6), and the stripping tower (7) are connected in series through pipelines.

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