A method for improving the quality of lubricating oil base oil

Abstract

The application discloses a method for improving the quality of lubricating oil base oil. The method is a hydrocracking process in which a hydrofining reactor and a hydrocracking reactor are connected in series, a hydrocracking catalyst bed and a post-hydrofining catalyst bed are arranged in the hydrocracking reactor, and the method comprises the following steps: feeding a wax oil raw material and hydrogen into the hydrofining reactor, and performing a hydrofining reaction on the raw material and the hydrogen by using the hydrofining catalyst to obtain a hydrofining stream; feeding the hydrofining stream into the hydrocracking reactor, and feeding the material P into the hydrocracking reactor between the hydrocracking catalyst bed and the post-hydrofining catalyst bed; performing air cooling on the obtained product, and performing water injection on the product in the air cooling process so that the material P in the product is carried out of the reaction system by the water phase; and performing separation and fractionation on the oil phase after the air cooling to obtain a tail oil fraction heavier than diesel oil, and using the tail oil fraction as the lubricating oil base oil. The method can improve the quality of the lubricating oil base oil product while ensuring the yield of the lubricating oil base oil in the hydrocracking device.

Description

Technical Field

[0001] This invention relates to the field of hydrocracking technology, and more specifically to a method for improving the quality of lubricating oil base oil. Background Technology

[0002] In recent years, the demand for refined oil products has undergone significant changes. Demand for diesel and gasoline has gradually declined, while demand for lubricating oil base oils has grown rapidly. The hydrocracking process can produce tail oil components that can be used as lubricating oil base oils. The quality properties of lubricating oil base oils determine the properties and grade of the lubricating oil. Higher-quality lubricating oil base oils can be used to produce higher-quality, higher-grade lubricating oil products, which helps improve the product's market competitiveness.

[0003] CN114479926B discloses a method for preparing lubricating oil base oil. The method includes the following steps: S1, vacuum wax oil is contacted with a hydrorefining catalyst in hydrorefining reaction zone I for desulfurization and denitrogenation; S2, the refined oil generated is passed through hydrocracking reaction zone II for mild conversion, achieving the conversion of refined long-chain macromolecular alkanes and cyclic hydrocarbons into smaller molecule hydrocarbons; S3, the fraction generated in hydrocracking reaction zone II enters reaction zone III for pour point depressing reaction, obtaining low-pour-point lubricating oil base oil; S4, the low-pour-point lubricating oil base oil is further contacted with a hydrorefining catalyst in hydrorefining reaction zone IV to obtain refined low-pour-point lubricating oil base oil, simultaneously accommodating the production of jet kerosene, low-pour-point diesel oil, and naphtha. Compared with conventional two-stage hydrocracking, this method can reduce investment in precious metal hydroisomerization catalysts and also lower investment costs in the process. However, the reaction temperatures in the hydrocracking reaction zone II and the hydrodewaxing reaction zone III of this method are relatively high. Within this temperature range, long-chain macromolecular alkanes will undergo partial dehydrogenation. Although the subsequent hydrorefining reaction zone IV plays a refining role, the fractions entering the hydrorefining reaction zone IV are all alkanes, aromatics, and cycloalkanes. The adsorption energy of alkanes is lower than that of aromatics and cycloalkanes, making it difficult for them to undergo hydrorefining reactions. Therefore, this method does not significantly improve the quality of lubricating oil base oils. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for improving the quality of lubricating oil base oils. This method can improve the quality of lubricating oil base oil products while ensuring the yield of lubricating oil base oils in a hydrocracking unit.

[0005] This invention provides a method for improving the quality of lubricating oil base oil, employing a hydrocracking process in which a hydrorefining reactor and a hydrocracking reactor are connected in series. The hydrocracking reactor contains a hydrocracking catalyst bed and a post-hydrorefining catalyst bed. The method includes the following steps:

[0006] (1) Wax oil raw material and hydrogen enter the hydrorefining reactor, and come into contact with the hydrorefining catalyst to carry out the hydrorefining reaction, and obtain the hydrorefined stream.

[0007] (2) The hydrorefined stream from step (1) enters the hydrocracking reactor. The material P enters the hydrocracking reactor between the hydrocracking catalyst bed and the post-hydrorefining catalyst bed. The resulting product is air-cooled, and water is injected into the air-cooled product so that the material P in the product is carried out of the reaction system by the aqueous phase. The air-cooled oil phase is separated and fractionated to obtain a tail oil fraction heavier than diesel oil. The tail oil fraction is used as a base oil for lubricating oil. The material P is one or more of the following: C23-C35 olefin alcohols, olefin aldehydes, alkyne alcohols, alkyne aldehydes, olefin esters, and wax esters.

[0008] In the method of the present invention, a hydrocracking catalyst bed is set upstream of the hydrocracking reactor, and a post-hydrorefining catalyst bed is set downstream.

[0009] In the method of the present invention, the air-cooled oil phase is separated and fractionated to obtain light naphtha, heavy naphtha, jet fuel, diesel oil and tail oil fractions, wherein the tail oil fraction is used as a base oil for lubricating oil.

[0010] In the method of this invention, both the hydrorefining reactor and the hydrocracking reactor are fixed-bed reactors.

[0011] In the method of this invention, the hydrorefining reactor adopts a conventional top-feed, bottom-discharge method. In the hydrocracking reactor, the hydrorefined stream and hydrogen gas adopt a top-feed, bottom-discharge method.

[0012] In the method of this invention, the initial boiling point of the wax oil feedstock is generally 200℃~350℃, and the dry point is generally 500℃~600℃, preferably 530℃~590℃; the nitrogen content is below 2500μg / g, generally 500μg / g~2000μg / g; the sulfur content is not strictly limited, and the content of other impurities only needs to meet conventional requirements. The wax oil feedstock can be at least one of various straight-run or secondary-processed wax oils obtained from processing naphthenic crude oil, intermediate-based crude oil, or paraffinic crude oil, preferably straight-run wax oil components or deasphalted oils from primary-processed paraffinic crude oil, which can be selected from at least one of various vacuum gas oil (VGO) and deasphalted oil (DAO) obtained from processing paraffinic crude oil, such as Daqing VGO, DAO, Changqing VGO, DAO, Shengli VGO, DAO, or several of them. The hydrogen gas is a feedstock with a commonly used industrial impurity content that meets the requirements.

[0013] In the method of this invention, the operating conditions of the hydrorefining reactor in step (1) are as follows: the reaction temperature is 300℃~420℃, preferably 310℃~390℃; the reactor inlet pressure is 6MPa~20MPa, preferably 8MPa~18MPa; and the volume hourly space velocity is 0.5h. -1 ~3.0h -1 0.6h is preferred -1 ~2.5h -1 The hydrogen-to-oil volume ratio at the reactor inlet is 400–1200, preferably 500–1100.

[0014] In the method of this invention, the hydrorefining catalyst and the post-hydrorefining catalyst can be conventional hydrocracking pretreatment catalysts, or the desired catalyst can be prepared according to common knowledge in the art. Conventional hydrocracking pretreatment catalysts include a support and a hydrogenation metal. Based on the weight of the catalyst, they typically include a Group VIB metal component from the periodic table, such as tungsten and / or molybdenum, with a mass content of 10%–35% (based on oxides), preferably 15%–30%, and a Group VIII metal, such as nickel and / or cobalt, with a mass content of 1%–7% (based on oxides), preferably 1.5%–6%. The support is an inorganic refractory oxide, generally selected from at least one of alumina, amorphous silica-alumina, silica, titanium dioxide, etc. The preferred metal for the hydrorefining catalyst is a Mo-Ni combination with a specific surface area ≥160 m². 2 / g, pore volume ≥0.3mL / g. The preferred metal catalyst for post-hydrogenation refining is a Mo-Co combination with a specific surface area ≥160m². 2 / g, pore volume ≥0.3mL / g. The conventional hydrocracking pretreatment catalyst can be any of the existing commercial catalysts, such as the 3936, 3996, FF-12, FF-16, FF-26, FF-36, FF-46, and FF-66 catalysts developed by the Fushun Petrochemical Research Institute (FRIPP). The refining reaction is a process of removing impurities such as desulfurization, denitrification, and aromatic saturation. The hydrorefining catalyst and the post-hydrorefining catalyst can be the same or different.

[0015] In the method of this invention, the operating conditions of the hydrocracking catalyst bed in the hydrocracking reactor in step (2) are as follows: the reaction temperature is 385℃~420℃, preferably 395℃~410℃; the reactor inlet pressure is 12MPa~18MPa, preferably 13MPa~15MPa; and the volume hourly space velocity is 0.5h. -1 ~5.0h -1 0.6h is preferred -1 ~3.0h -1 The hydrogen-to-oil volume ratio at the reactor inlet is 400–2000, preferably 500–1100. Generally, during the later stages of operation, the hydrocracking reaction temperature is 400℃–415℃.

[0016] In the method of this invention, the operating conditions of the hydrorefining catalyst bed after the hydrocracking reactor in step (2) are as follows: the reaction temperature is 360℃~435℃, preferably 375℃~430℃; the volume hourly space velocity of the hydrocracking bed products is 10h. -1 ~25h -1 12h preferred -1 ~20h -1 The hydrogen-to-oil volume ratio is 400–2000, preferably 500–1100, and the reactor inlet pressure is 6 MPa–20 MPa, preferably 8 MPa–18 MPa. Generally, the reaction temperature of the post-hydrogenation refining catalyst bed is 390℃–430℃ during the later stages of operation.

[0017] In the method of this invention, the hydrocracking catalyst is a conventional hydrocracking catalyst used for producing lubricating oil base oils, generally a high-oil type hydrocracking catalyst. The hydrocracking catalyst includes a cracking component and a hydrogenation component, and may also include a binder. The cracking component typically includes at least one amorphous silica-alumina and / or molecular sieves, such as Y-type, β-type, or USY molecular sieves, and the binder is typically alumina and / or silica. The hydrogenation component is selected from at least one metal, metal oxide, or metal sulfide from Group VIB, Group VIIB, or Group VIII, with the hydrogenation metal more preferably being one or more of iron, chromium, molybdenum, tungsten, cobalt, and nickel. Based on the weight of the catalyst, the hydrogenation component, calculated as oxides, has a content of 23%–30%, preferably 24%–28%, the molecular sieve content is 14%–22%, preferably 15%–20%, and the remainder is amorphous silica-alumina and / or binder components. Conventional hydrocracking catalysts can be selected from various existing commercial catalysts, such as FC-40, FC-60, FC-80, and FC-80B developed by FRIPP. Specific hydrocracking catalysts can also be prepared according to common knowledge in the field.

[0018] In the method of the present invention, the material P is one or more of the following: C23-C35 olefin alcohols, olefin aldehydes, alkyne alcohols, and alkyne aldehydes; further selected from one or more of all-trans-β-alincaroaldehyde, triacontadecene-2,3-diol, lauryl myristate, dimethyl hexadecanoate, and tetradecenol.

[0019] In the method of the present invention, preferably, the volume hourly space velocity of the material P relative to the post-hydrocracking catalyst is 31% to 72% of the total volume hourly space velocity of the hydrocracking bed products and the material P, more preferably 32% to 60%, for example, but not limited to 32%, 35%, 40%, 50%, 55%, 60%, etc., and any value within the range formed by any two of these values.

[0020] The inventors discovered that the main reason for the poor quality of the tail oil produced by hydrocracking units as a base oil for lubricating oil is that long-chain alkane components undergo dehydrogenation reactions in the post-refining catalyst reaction zone, generating components with higher unsaturation, such as long-chain olefins and long-chain alkynes. These components increase the instability of the lubricating oil base oil, thus affecting the product quality. Effectively retaining long-chain alkane components would be highly beneficial for improving the stability of the lubricating oil base oil and the quality of the lubricating oil product. Further research by the inventors revealed that material P will react at relatively low space velocities (1.5–3.0 h⁻¹). -1 The hydrodeoxygenation reaction is carried out at relatively low temperatures (300–330 °C), but post-hydrogenation purification at high space velocities (3.1–18.0 h⁻¹) is necessary. -1 Deoxygenation reactions are difficult to occur in reaction environments with high temperatures (360℃~435℃). Therefore, introducing material P before post-hydrocracking refining in the hydrocracking reactor can inhibit the dehydrogenation reaction of long-chain alkane components in the material during post-refining, which helps to efficiently retain long-chain alkane components. At the same time, material P is highly soluble in water, so material P can be effectively removed before product fractionation. Thus, it will not only not affect the yield and composition of hydrocracking tail oil, but also ensure the stability of subsequent lubricating oil base oil and the product quality of lubricating oil.

[0021] Further research by the inventors revealed that the content of C26-C31 long-chain cycloalkanes in the hydrocracking catalyst bed products changes before and after passing through the post-hydrorefining catalyst bed. When the retention rate of C26-C31 long-chain cycloalkanes is lower than 80% due to dehydrogenation reaction with the post-hydrorefining catalyst, it significantly affects the stability of the lubricating oil base oil. Therefore, feedstock P is added to inhibit the dehydrogenation reaction of C26-C31 long-chain cycloalkanes. However, since there is a chemical reaction equilibrium between feedstock P, hydrocracking bed products, and post-hydrorefining catalyst, the dehydrogenation reaction of C26-C31 long-chain cycloalkanes cannot be completely prevented. It is preferable to control a certain retention rate.

[0022] In the method of this invention, preferably, after the hydrocracking bed product stream passes through the post-hydrorefining catalyst, the retention rate of C26-C31 long-chain cycloalkanes is above 80 wt%, more preferably 85 wt% to 92 wt%. Wherein, the retention rate of C26-C31 long-chain cycloalkanes = (concentration of C26-C31 long-chain cycloalkanes in the post-refined product / concentration of C26-C31 long-chain cycloalkanes in the hydrocracking bed product stream) * 100%.

[0023] Hydrocracking units typically involve a separation process (generally including hot high-performance fraction, hot low-performance fraction, cold high-performance fraction, and cold low-performance fraction) before fractionation of the hydrocracking products. This process separates the gaseous components from the products, improving the efficiency of the fractionation process and reducing energy consumption. Specifically, a water injection process occurs after the hot high-performance fraction and before air cooling. This is to prevent the precipitation of ammonium salts during the cooling process, which could clog pipelines and equipment. Since the material P in the method of this invention is highly soluble in water, it can be carried out of the reaction system by the aqueous phase.

[0024] In the method of the present invention, an air cooling device is set up before the fractionation of the obtained product. The air cooling device is injected with water so that the material P in the product is carried out of the reaction system by the aqueous phase. The amount of water injected is 2 to 30 times the mass flow rate of material P, preferably 3 to 9 times the mass flow rate of material P.

[0025] In the method of this invention, the subsequent product separation, fractionation process and various qualified products are all conventional technical contents familiar to those skilled in the art, and will not be described in detail here.

[0026] In the method of this invention, the final boiling point of light naphtha is 50-68℃, preferably 55-62℃; the initial boiling point of heavy naphtha is 55-75℃, preferably 60-68℃, and the final boiling point is 120-190℃, preferably 145-180℃; the initial boiling point of jet fuel is 160-200℃, preferably 170-185℃, and the final boiling point is 200-230℃, preferably 205-220℃; the initial boiling point of diesel fuel is 215-270℃, preferably 215-265℃, and the final boiling point is 300-380℃, preferably 310-380℃; and the initial boiling point of tail oil (lubricating oil base oil) is 360-400℃, preferably 375-395℃.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) The catalysts used in the hydrocracking unit in the method of the present invention are all conventional catalysts, and there is no need to develop new catalysts;

[0029] (2) In the method of the present invention, the quality problem of lubricating oil base oil is specifically improved by introducing material P, without causing changes in product distribution and other product properties;

[0030] (3) In the method of the present invention, material P is soluble in water and can be discharged from the system with the demineralized water during the separation of hydrocracking products. It will not enter the fractionation system, so that the lubricating oil base oil components will not have any impurities. The process is energy-saving and efficient.

[0031] (4) The method of the present invention has strong applicability and can improve the quality of lubricating oil base oil for any hydrocracking catalyst and process conditions. The adjustment method is flexible. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the process of the present invention;

[0033] The annotations in the attached figures are explained as follows:

[0034] 1-Feedstock oil and hydrogen, 2-Hydrorefining reactor, 3-Hydrorefining product, 4-Hydrocracking reactor, 5-Hydrocracking catalyst bed, 6-Post-hydrorefining catalyst bed, 7-Feed P, 8-Hydrocracking product, 9-Water, 10-Air cooler, 11-Cooled material, 12-Cold high-efficiency fractionator, 13-Cold high-efficiency gas phase component, 14-Acidic water, 15-Cold high-efficiency oil phase component, 16-Cold low-efficiency fractionator, 17-Cold low-efficiency gas phase component, 18-Cold low-efficiency oil phase component, 19-Fracturing system, 20-Naphtha, 21-Jet kerosene, 22-Diesel, 23-Lubricating oil base oil. Detailed Implementation

[0035] The method of the present invention will be described in more detail below with reference to specific embodiments and comparative examples.

[0036] The hydrocracking method for improving the quality of lubricating oil base oil provided by this invention, such as... Figure 1 As shown, it includes:

[0037] Feedstock oil and hydrogen 1 are sequentially passed through hydrorefining reactor 2 and hydrocracking reactor 4 (equipped with hydrocracking catalyst bed 5 and post-hydrorefining catalyst bed 6). Material P7 is introduced between the hydrocracking catalyst bed 5 and the post-hydrorefining catalyst bed 6. The product from the hydrocracking bed and material P7 are passed together through the post-hydrorefining catalyst bed 6 to obtain hydrocracking product 8. Hydrocracking product 8 is mixed with water 9 and then cooled in air cooler 10. The cooled material 11 enters cold high-efficiency separator 12 for separation to obtain cold high-efficiency gas phase component 13, cold high-efficiency oil phase component 15, and acidic water 14. The acidic water 14 contains material P7 dissolved in the water. The cold high-phase oil phase component 15 enters the cold low-phase separator 16 for separation to obtain the cold low-phase gas phase component 17 and the cold low-phase oil phase component 18. The cold low-phase oil phase component 18 enters the fractionation system 19 for separation to obtain naphtha 20, jet fuel 21, diesel fuel 22, and lubricating oil base oil 23.

[0038] In the embodiments and comparative examples of the present invention, the distillation range of light naphtha is the fraction below 62°C, the distillation range of heavy naphtha is 62 to 178°C, the distillation range of jet fuel is 178 to 220°C, the distillation range of diesel fuel is 220 to 380°C, and the tail oil (lubricating oil base oil) is the fraction above 380°C.

[0039] The properties of the feedstock used in the following examples and comparative examples are shown in Table 1, and the main properties of the catalysts used in the examples and comparative examples are shown in Table 2.

[0040] Table 1 Main Properties of Crude Oil

[0041] project crude oil type Straight-run wax oil Density, g / cm 3 ]] 0.9032 Distillation range, °C 305～535 S, wt% 1.37 N, μg / g 1098

[0042] Table 2 Main properties of the catalyst

[0043]

[0044] Example 1

[0045] Adopting such Figure 1 This is a series process flow. Hydrorefining catalyst A is used, hydrocracking catalyst B is used, and post-hydrorefining catalyst A is used again. Feedstock P uses all-trans-β-alincaroaldehyde, controlling the tail oil yield to approximately 35%, and sampling and analyzing the properties of the tail oil products.

[0046] Example 2

[0047] Adopting such Figure 1 This is a series process flow. Hydrorefining catalyst A is used, hydrocracking catalyst B is used, and post-hydrorefining catalyst C is used. Feedstock P uses triacontadecene-2,3-diol and lauryl myristate (where the mass ratio of triacontadecene-2,3-diol to lauryl myristate is 0.5:2.1), controlling the tail oil yield to approximately 35%, and sampling and analyzing the properties of the tail oil products.

[0048] Example 3

[0049] Adopting such Figure 1 This is a series process flow. Hydrorefining catalyst A is used, hydrocracking catalyst B is used, and post-hydrorefining catalyst C is used. Feedstock P consists of all-trans-β-alincaroaldehyde, triacontadecene-2,3-diol, dimethyl hexadecanoate, and tetradecenool (where the mass ratio of all-trans-β-alincaroaldehyde, triacontadecene-2,3-diol, dimethyl hexadecanoate, and tetradecenool is 2.6:1.1:0.6:0.8). The tail oil yield is controlled at approximately 40%, and the properties of the tail oil product are sampled and analyzed.

[0050] Comparative Example 1

[0051] Compared with Example 1, the only difference is that material P is not introduced and water is injected into the air-cooled room in a conventional manner.

[0052] A conventional single-stage series process was adopted. Catalyst A was used for hydrorefining, catalyst B for hydrocracking, and catalyst A was used for post-hydrorefining. The tail oil yield was controlled at approximately 35%, and the properties of the tail oil products were sampled and analyzed.

[0053] Comparative Example 2

[0054] Compared with Example 3, the only difference is that material P is not introduced and water is injected into the air-cooled room in a conventional manner.

[0055] A conventional single-stage series process was adopted. Catalyst A was used for hydrorefining, catalyst B for hydrocracking, and catalyst C for post-hydrorefining. The tail oil yield was controlled at approximately 40%, and the properties of the tail oil products were sampled and analyzed.

[0056] Comparative Example 3

[0057] The difference compared to Example 3 is that the material P is different.

[0058] Adopting such Figure 1 This is a series process flow. Hydrorefining catalyst A is used, hydrocracking catalyst B is used, and post-hydrorefining catalyst C is used. Feedstock P consists of ninhydrin hydrate, 4-methylumbelliferone, rhein, and cinnamyl alcohol (with a mass ratio of ninhydrin hydrate, 4-methylumbelliferone, rhein, and cinnamyl alcohol of 2.6:1.1:0.6:0.8). The tail oil yield is controlled at approximately 40%, and samples are taken to analyze the properties of the tail oil product.

[0059] The effects of the above embodiments and comparative examples are compared in Table 3.

[0060] Table 3. Reaction conditions and results for each embodiment and comparative example.

[0061]

[0062]

Claims

1. A method for improving the quality of lubricating oil base oil, comprising a hydrocracking process using a hydrorefining reactor and a hydrocracking reactor connected in series, wherein the hydrocracking reactor is provided with a hydrocracking catalyst bed and a post-hydrorefining catalyst bed, the method comprising the following steps: (1) Wax oil raw material and hydrogen enter the hydrorefining reactor, and come into contact with the hydrorefining catalyst to carry out the hydrorefining reaction, and obtain the hydrorefined stream. (2) The hydrorefined stream from step (1) enters the hydrocracking reactor. The material P enters the hydrocracking reactor between the hydrocracking catalyst bed and the post-hydrorefining catalyst bed. The resulting product is air-cooled, and water is injected into the air-cooled product so that the material P in the product is carried out of the reaction system by the aqueous phase. The air-cooled oil phase is separated and fractionated to obtain a tail oil fraction heavier than diesel oil. The tail oil fraction is used as a base oil for lubricating oil. The material P is one or more of the following: C23-C35 olefin alcohols, olefin aldehydes, alkyne alcohols, alkyne aldehydes, olefin esters, and wax esters.

2. The method according to claim 1, characterized in that, A hydrocracking catalyst bed is set upstream of the hydrocracking reactor, and a post-hydrorefining catalyst bed is set downstream.

3. The method according to claim 1, characterized in that, After air cooling, the oil phase is separated and fractionated to obtain light naphtha, heavy naphtha, jet fuel, diesel oil and tail oil fractions, the tail oil fraction being used as lubricating oil base oil.

4. The method according to claim 1, characterized in that, Both the hydrorefining reactor and the hydrocracking reactor are fixed-bed reactors; the hydrorefining reactor adopts a top-feed and bottom-discharge method; in the hydrocracking reactor, the hydrorefining stream and hydrogen gas adopt a top-feed and bottom-discharge method.

5. The method according to claim 1, characterized in that, The initial boiling point of the wax oil raw material is 200℃~350℃, and the dry point is 500℃~600℃, preferably 530℃~590℃; the nitrogen content is below 2500μg / g, preferably 500μg / g~2000μg / g.

6. The method according to claim 1, characterized in that, The operating conditions of the hydrorefining reactor in step (1) are as follows: reaction temperature is 300℃~420℃, preferably 310℃~390℃; reactor inlet pressure is 6MPa~20MPa, preferably 8MPa~18MPa; volume hourly space velocity is 0.5h. -1 ~3.0h -1 0.6h is preferred -1 ~2.5h -1 The hydrogen-to-oil volume ratio at the reactor inlet is 400–1200, preferably 500–1100.

7. The method according to claim 1, characterized in that, The aforementioned hydrorefining catalyst and post-hydrorefining catalyst are hydrocracking pretreatment catalysts; Preferably, the hydrorefining catalyst is a Mo-Ni metal combination with a specific surface area of ​​≥160 m². 2 / g, pore volume ≥ 0.3mL / g; Preferably, the catalyst for post-hydrogenation refining is a Mo-Co metal combination with a specific surface area of ​​≥160 m². 2 / g, pore volume ≥0.3mL / g.

8. The method according to claim 1, characterized in that, The operating conditions of the hydrocracking catalyst bed in the hydrocracking reactor in step (2) are as follows: reaction temperature is 385℃~420℃, preferably 395℃~410℃; reactor inlet pressure is 12MPa~18MPa, preferably 13MPa~15MPa; volume hourly space velocity is 0.5h. -1 ~5.0h -1 0.6h is preferred -1 ~3.0h -1 The hydrogen-to-oil volume ratio at the reactor inlet is 400–2000, preferably 500–1100.

9. The method according to claim 1, characterized in that, The operating conditions for the hydrorefining catalyst bed after the hydrocracking reactor in step (2) are as follows: the reaction temperature is 360℃~435℃, preferably 375℃~430℃; the volume hourly space velocity of the hydrocracking bed products is 10h. -1 ~25h -1 12h preferred -1 ~20h -1 The hydrogen-to-oil volume ratio is 400–2000, preferably 500–1100, and the reactor inlet pressure is 6 MPa–20 MPa, preferably 8 MPa–18 MPa.

10. The method according to claim 1, characterized in that, The hydrocracking catalyst comprises a cracking component and a hydrogenation component; the cracking component typically comprises amorphous silica-alumina and / or molecular sieves, such as at least one of Y-type, β-type, or USY molecular sieves; the hydrogenation component is selected from at least one of Group VIB, Group VIIB, or Group VIII metals, metal oxides, or metal sulfides, and the hydrogenation metal is more preferably one or more of iron, chromium, molybdenum, tungsten, cobalt, and nickel; Preferably, based on the weight of the catalyst, the content of the hydrogenation component, calculated as oxide, is 23% to 30%, more preferably 24% to 28%, and the content of molecular sieve is 14% to 22%, more preferably 15% to 20%.

11. The method according to claim 1, characterized in that, The material P is one or more of the following: C23-C35 olefin alcohols, olefin aldehydes, alkyne alcohols, and alkyne aldehydes; further selected from one or more of all-trans-β-alincaroaldehyde, triacontadecene-2,3-diol, lauryl myristate, dimethyl hexadecanoate, and tetradecenol.

12. The method according to claim 1, characterized in that, Compared to the post-hydrocracking catalyst, the volume hourly space velocity of the material P accounts for 31% to 72% of the total volume hourly space velocity of the hydrocracking bed products and the material P, more preferably 32% to 60%.

13. The method according to claim 1, characterized in that, After the hydrocracking bed product flows through the post-hydrorefining catalyst, the retention rate of long-chain cycloalkanes of C26-C31 is above 80 wt%, and is further preferred to be 85 wt% to 92 wt%.

14. The method according to claim 1, characterized in that, An air-cooling device is installed before the fractionation of the obtained product. The air-cooling device is injected with water so that material P in the product is carried out of the reaction system by the aqueous phase. The amount of water injected is 2 to 30 times the mass flow rate of material P, preferably 3 to 9 times the mass flow rate of material P.

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