A method and system for producing a low-cloud-point lubricating oil base oil

Abstract

The application discloses a production method and a production system of low-haze lubricating oil base oil, and the production system comprises a first reaction zone, a first separation zone, an isomerization and condensation reduction gas-liquid separation zone, a second reaction zone, a second gas-liquid separator, a second fractionating column and a hydrofining reaction zone. The application also provides a production method of low-haze lubricating oil base oil. In the application, two-ring or more ring naphthenes and part of non-ideal components such as aromatics in a lubricating oil base oil raw material are separated out through selective adsorption, so that the isomerization and condensation reduction reaction is only carried out on the pretreated raw material rich in long-chain alkanes, long-side-chain monocyclic naphthenes and long-chain monocyclic aromatics, the separated non-ideal components are subjected to the hydrofining reaction, and the lubricating oil base oil product is generated.

Description

Technical Field

[0001] This invention belongs to the field of petrochemicals, and in particular relates to a method and system for producing lubricating oil base oil. Background Technology

[0002] With increasingly stringent environmental regulations and the rapid development of the machinery industry, higher and higher requirements are being placed on the performance of lubricating oil base oils. Traditional lubricating oil base oil production employs solvent refining processes, which mainly involve two steps: solvent refining to remove non-ideal components such as aromatics and solvent dewaxing to ensure the low-temperature flow properties of the base oil. In addition, supplementary refining with clay or hydrotreating is generally required. However, the development and application of traditional processes are limited by high energy consumption and heavy pollution. In recent years, the hydrotreating process for lubricating oil production has developed rapidly. The hydrotreating process refers to the production of lubricating oil base oils using hydrocracking or a combined process of hydrotreating-isomerization dewaxing-hydrorefining. It offers advantages such as greater feedstock flexibility, higher base oil yield, and higher economic value of by-products.

[0003] In existing methods for preparing high viscosity index lubricating oil base oil products, some employ a full-range or wide-range feedstock and produce high viscosity index lubricating oil base oils through a stepwise isomerization dewaxing-product separation method. Others cut the raw material into narrow fractions and then use these narrow fractions as feedstocks for hydroisomerization dewaxing, thus solving the problem of producing high viscosity index light lubricating oil base oils.

[0004] CN102911726A discloses a method for producing high viscosity index lubricating oil base oil. The method uses waxy oil that does not require pre-fractionation as feed for hydroisomerization dewaxing. The oil first enters the first hydroisomerization dewaxing reaction zone to complete a hydroisomerization reaction of appropriate depth. The reaction products are then fractionated to obtain a light lubricating oil base oil product with a high viscosity index and a pour point that meets the requirements, as well as a heavy base oil component with a relatively high pour point. The heavy base oil component continues to enter the second hydroisomerization dewaxing reaction zone, where the reaction products are fractionated to obtain a heavy lubricating oil base oil product with a high viscosity index and a pour point that meets the requirements.

[0005] US7,198,710 discloses a method for producing high viscosity index lubricating oil base oil from Fischer-Tropsch wax. First, the Fischer-Tropsch wax is fractionated to obtain light and heavy components. Then, hydroisomerization dewaxing is performed on each component to lower its pour point, resulting in a light lubricating oil base oil with a pour point that meets the requirements. Since the heavy component does not meet the pour point requirements after hydroisomerization dewaxing, solvent dewaxing is used to further lower the pour point of the heavy component, finally yielding a heavy lubricating oil base oil product with a pour point that meets the requirements.

[0006] In summary, while using full-range or wide-range feedstocks can produce lubricating oil base oils that simultaneously meet both pour point and viscosity index requirements, heavy lubricating oil base oils may exhibit turbidity (higher cloud point) under certain low-temperature storage conditions. This significantly affects the appearance of the base oil and consequently impacts product sales. Although increasing the depth of secondary isomerization dewaxing or solvent dewaxing can lower the cloud point of the base oil, it also results in a loss of viscosity index, leading to a trade-off and ultimately low economic efficiency. Summary of the Invention

[0007] During their research, the inventors discovered that long-chain isoalkanes and long-side-chain monocyclic cycloalkanes are ideal components for high viscosity index lubricating oil base oils. However, apart from Fischer-Tropsch synthetic oils (FT oils) and polyesters, raw materials for producing lubricating oil base oils from natural petroleum products, such as hydrocracking tail oils, hydrotreated wax oils, hydrorefined wax residues, and hydrorefined wax pastes, contain not only long-chain isoalkanes, long-side-chain monocyclic cycloalkanes, and long-chain monocyclic aromatics, but also a certain amount of bicyclic or higher cycloalkanes and aromatics—non-ideal components. These non-ideal components cannot be converted into high viscosity index components during isomerization dewaxing and pour point depressing, and their presence severely restricts the improvement of the viscosity index of isomerization dewaxing products-lubricating oil base oils. The inventors proposed that if these non-ideal components in the raw materials can be removed beforehand, without subsequent isomerization dewaxing treatment, the viscosity index of isomerization dewaxing products-lubricating oil base oils can be improved, and the hydrogen consumption in the isomerization dewaxing process can be significantly reduced, thereby lowering equipment operation and production costs. This invention is based on the above-mentioned findings.

[0008] To address the problems and shortcomings of existing technologies, the main objective of this invention is to provide a method and system for producing low-cloud-point lubricating oil base oil. First, a primary selective adsorption process separates non-ideal components such as bicyclic or higher-ring cycloalkanes and some aromatics from the lubricating oil base oil feedstock. This process targets only the pre-treated feedstock rich in long-chain alkanes, long-side-chain monocyclic cycloalkanes, and long-chain monocyclic aromatics for isomerization and pour point depletion. The separated non-ideal components undergo hydrorefining to produce the lubricating oil base oil product. The isomerized and poured point depleted oil then undergoes a secondary selective adsorption process to adsorb unconverted long-chain n-alkanes, long-side-chain monocyclic cycloalkanes, long-chain monocyclic aromatics, and lightly isomerized long-chain isoalkanes that affect the oil's cloud point. This process is repeated with another isomerization and pour point depletion reaction, ultimately producing a low-cloud-point, high-viscosity-index lubricating oil base oil product.

[0009] To achieve the above-mentioned objective, the first aspect of the present invention provides a method for producing a low cloud point lubricating oil base oil, comprising the following steps:

[0010] (1) The raw material enters the first reaction zone and is processed by contacting the catalyst. After processing, the first feed stream is obtained.

[0011] (2) The first feed obtained in step (1) is mixed with hydrogen and then enters the hydrorefining reaction zone, where it reacts with the hydrorefining catalyst. The reaction products are separated to obtain light white oil, industrial white oil and rubber filler oil.

[0012] (3) When the refractive index (20°C) of the first feed stream is 0.1% to 5% higher than that of the raw material (20°C), preferably 0.5% to 2.5%, the raw material is stopped from entering the first reaction zone, and hydrogen is introduced into the first reaction zone. Under the action of the catalyst, the isomerization dewaxing reaction occurs. The isomerization dewaxing reaction products are separated by gas and liquid to obtain gaseous feed stream and isomerization dewaxing oil.

[0013] (4) The isomerized pour point depressed oil from step (3) enters the second reaction zone and is processed by contacting the catalyst. After processing, the second stream is obtained. The second stream is separated to obtain light lubricating oil base oil, medium lubricating oil base oil and heavy lubricating oil base oil products.

[0014] (5) When the refractive index (20°C) of the second feed stream is 0.1% to 3% higher than that of the isomeric pour point depressant (20°C), preferably 0.3% to 2%, the isomeric pour point depressant is stopped from entering the second reaction zone, hydrogen is introduced into the second reaction zone, and a reaction occurs under the action of a catalyst. The reaction products are separated into gas phase feed stream and liquid phase feed stream after gas-liquid separation. The liquid phase feed stream is mixed with the second feed stream for separation.

[0015] Furthermore, in the above-mentioned production method of low cloud point lubricating oil base oil, the raw materials can be selected from one or more of hydrocracking tail oil, hydrotreated VGO, hydrotreated wax paste, and hydrotreated wax off oil, and the wax content of the raw materials is not less than 60 wt%.

[0016] Furthermore, in the above-mentioned method for producing low-turbidity-point lubricating oil base oil, one or more reactors are set in the first reaction zone, preferably two reactors, denoted as reactor A and reactor B respectively. The two reactors are connected in parallel and can be switched according to the actual production process needs. When the raw material entering reactor A is stopped, the raw material is switched to reactor B, which is connected in parallel with reactor A, and steps (1) to (3) are repeated to ensure continuous operation of the entire set of equipment. Reactor A and reactor B are preferably identical and filled with the same adsorbent. Reactor A and reactor B can be one or more of the existing fixed-bed reactors, fluidized-bed reactors, and slurry-bed reactors, with fixed-bed reactors being preferred.

[0017] Furthermore, in the above-mentioned method for producing low-cloud-point lubricating oil base oil, the operating conditions (adsorption reaction) of the first reaction zone in step (1) are: temperature of 40℃~250℃, preferably 60℃~200℃, pressure of 0.01MPa~0.5MPa, preferably 0.08~0.1MPa, and volume hourly space velocity of 0.05h⁻¹. -1 ~5.0h -1 Preferably 0.1h -1 ~2.0h -1 .

[0018] Furthermore, in the above-mentioned method for producing low-cloud-point lubricating oil base oil, the catalyst comprises an embedded molecular sieve of TON structure molecular sieve and 5A type molecular sieve, an active metal component, and an inorganic refractory oxide; preferably, the TON structure molecular sieve is embedded on at least a portion of the surface of the 5A type molecular sieve with a predetermined surface coverage rate. A suitable surface coverage rate may be more than 0.5% or more than 1%, and less than 50% or less than 20%, but the present invention is not limited thereto.

[0019] According to one embodiment of the present invention, the specific surface area of ​​the embedded molecular sieve is 300 m². 2 / g~600m 2 / g, pore volume 0.15cm 3 / g~0.40cm 3 / g.

[0020] According to one embodiment of the present invention, the catalyst has a specific surface area of ​​200 m². 2 / g~550m 2 / g, pore volume 0.25 cm³ 3 / g~0.60 cm 3 / g.

[0021] According to one embodiment of the present invention, the weight ratio of the 5A type molecular sieve to the TON structure molecular sieve is 1:80-3:1, preferably 1:30-1:1.

[0022] According to one embodiment of the present invention, the content of TON structured molecular sieve is 10wt%-80wt%, preferably 20wt%-60wt%, and the content of 5A type molecular sieve is 1wt%-50wt%, preferably 2wt%-20wt%, relative to the total weight of the catalyst of 100wt%.

[0023] According to one embodiment of the present invention, based on a total catalyst weight of 100wt%, the content of the embedded molecular sieve is 10wt%-90wt%, preferably 20wt%-70wt%, and the content of the active metal component, calculated as metal element, is 0.05wt%-5.0wt%, preferably 0.1wt%-1.0wt%.

[0024] According to one embodiment of the present invention, the inorganic refractory oxide is selected from one or more of alumina, titanium oxide, boron oxide, silicon oxide, zirconium oxide and magnesium oxide, preferably alumina.

[0025] According to one embodiment of the present invention, the active metal component is selected from at least one of the noble metals of Group VIII of the periodic table, preferably from at least one of Pt and Pd, especially Pt.

[0026] According to one embodiment of the present invention, the TON structure molecule is selected from one or more of ZSM-22, Theta-1, ISI-1, KZ-2 and NU-10, preferably ZSM-22.

[0027] According to one embodiment of the present invention, the 5A molecular sieve is derived from 5A molecular sieve.

[0028] According to one embodiment of the present invention, the catalyst is prepared by mixing an embedded molecular sieve with an inorganic refractory oxide, an extrusion aid, and a binder, further extruding the mixture to obtain a support, and then loading an active metal to obtain the catalyst.

[0029] According to one embodiment of the present invention, the extrusion aid and binder can be reagents commonly used in the art. The extrusion aid can be any one of guar gum powder and starch, and the binder is an aqueous solution of inorganic acid, such as nitric acid.

[0030] According to one embodiment of the present invention, the catalyst has dual functions of adsorption and hydroisomerization, and can selectively enrich long side-chain hydrocarbons, and then further hydroisomerize them, avoiding the occurrence of over-isomerization.

[0031] According to one embodiment of the present invention, the method for preparing the embedded molecular sieve includes the following steps:

[0032] (1) A gel mixture is obtained by contacting a silicon source, an aluminum source, and an alkali source in the presence of a template agent, a TON-structured molecular sieve, and water.

[0033] (2) The gel mixture is subjected to hydrothermal crystallization, then washed, dried and calcined to obtain the first embedded molecular sieve.

[0034] According to one embodiment of the present invention, the preparation method further includes the following steps:

[0035] (3) The first embedded molecular sieve is subjected to calcium exchange, and then washed, dried and calcined to obtain the second embedded molecular sieve.

[0036] According to one embodiment of the present invention, in step (1), the silicon source is selected from at least one of water glass, sodium silicate, methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, and butyl orthosilicate.

[0037] According to one embodiment of the present invention, in step (1), the alkali source is selected from at least one of alkali metal hydroxides, preferably sodium hydroxide.

[0038] According to one embodiment of the present invention, in step (1), the aluminum source is selected from at least one of sodium aluminate, aluminum isopropoxide, aluminum sulfate, aluminum hydroxide, aluminum oxide, and boehmite.

[0039] According to one embodiment of the present invention, in step (1), the template agent is selected from at least one of polyethylene oxide triblock copolymer (P123) and dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC).

[0040] According to one embodiment of the present invention, in step (1), the TON structure molecule is selected from one or more of ZSM-22, Theta-1, ISI-1, KZ-2 and NU-10, preferably ZSM-22.

[0041] According to one embodiment of the present invention, in step (1), the operating conditions for contact include: a temperature of 15°C-30°C and a time of 1h-4h in the presence of stirring.

[0042] According to one embodiment of the present invention, in step (1), the molar ratio of the alkali source (calculated as oxide), the silicon source (calculated as SiO2), the aluminum source (calculated as Al2O3), the template agent and water is (0.5-2.5):1:(0.4-0.7):(0.001-0.08):(30-200), and the amount of the TON structure molecular sieve is 0.3-8 times, preferably 1-7 times, the amount of silicon source added.

[0043] According to one embodiment of the present invention, in step (2), the hydrothermal crystallization temperature is 60℃-120℃ and the crystallization time is 2h-16h.

[0044] According to one embodiment of the present invention, in step (2), the drying temperature is 80℃-200℃ and the drying time is 2h-24h.

[0045] According to one embodiment of the present invention, in step (2), the calcination temperature is 400℃-600℃ and the calcination time is 2h-12h.

[0046] According to one embodiment of the present invention, in step (3), the operating conditions for calcium exchange include: an exchange temperature of 60℃-100℃, an exchange time of 1h-12h, and a calcium ion concentration in the calcium exchange solution of 0.1mol / L-2.5mol / L.

[0047] According to one embodiment of the present invention, in step (3), the drying temperature is 80℃-150℃ and the drying time is 2h-12h.

[0048] According to one embodiment of the present invention, in step (3), the calcination temperature is 300℃-500℃ and the calcination time is 2h-8h.

[0049] Furthermore, in the above-mentioned production method of low-cloud-point lubricating oil base oil, the operating conditions of the hydrorefining reaction zone are as follows: reaction temperature is 180℃~300℃, preferably 200℃~260℃; hydrogen partial pressure is 2.0MPa~18.0MPa, preferably 10.0~15.0MPa; and volume hourly space velocity is 0.2h⁻¹. -1 ~6.0h -1 Preferably 0.3 h -1 ~1.8h -1 The hydrogen-to-oil volume ratio is 400:1 to 1500:1, preferably 600:1 to 800:1.

[0050] Furthermore, in the above-mentioned production method of low-cloud-point lubricating oil base oil, the hydrorefining catalyst can be an existing hydrorefining catalyst in the art, such as a commercially available product, or it can be self-made according to existing preparation methods in the art. Specifically, the FMTA-2 hydrorefining catalyst developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. can be used.

[0051] Furthermore, in the above-mentioned production method of low-turbidity-point lubricating oil base oil, the hydrorefining reaction zone is equipped with one or more reactors. The reactor can be selected from at least one of fixed-bed reactors, fluidized-bed reactors, boiling-bed reactors, and slurry-bed reactors, with a fixed-bed reactor being preferred.

[0052] Furthermore, in the above-mentioned method for producing low-turbidity-point lubricating oil base oil, in step (3), when the refractive index (20°C) of the first feed stream is 0.5 to 2.5% higher than the refractive index (20°C) of the raw material, the raw material is stopped from entering reactor A in the first reaction zone.

[0053] Furthermore, in the above-mentioned method for producing low-cloud-point lubricating oil base oil, the operating conditions (isomeric pour point depletion reaction) of reactor A in the first reaction zone in step (3) are as follows: reaction temperature is 200–420℃, preferably 270–380℃; reaction pressure is 1.0–20.0 MPa, preferably 3.0–15.0 MPa; and volume hourly space velocity is 0.1–10.0 h⁻¹. -1 Preferably, it is 0.5 to 3.0 h. -1 The hydrogen-to-oil volume ratio is 100:1 to 1500:1, preferably 100:1 to 400:1.

[0054] Furthermore, in the above-mentioned method for producing low-cloud-point lubricating oil base oil, the operating conditions (adsorption reaction) of reactor B in the first reaction zone in step (3) are as follows: temperature 40℃~250℃, preferably 60℃~200℃, pressure 0.01MPa~0.5MPa, preferably 0.08~0.1MPa, and volume hourly space velocity 0.05h⁻¹. -1 ~5.0h -1 Preferably 0.1h -1 ~2.0h -1 .

[0055] Furthermore, in the above-mentioned production method of low-cloud-point lubricating oil base oil, the second reaction zone is equipped with one or more reactors, preferably two reactors, denoted as reactor C and reactor D respectively. The two reactors are connected in parallel and can be switched according to the actual production process needs. When the isomerized pour point depressant is stopped from entering reactor C, the isomerized pour point depressant is switched to enter reactor D, which is connected in parallel with reactor C, and steps (4) and (5) are repeated. Reactor C and reactor D are preferably identical and filled with the same adsorbent. Reactor C and reactor D can be one or more of the existing fixed-bed reactors, fluidized-bed reactors, and slurry-bed reactors, with fixed-bed reactors being preferred.

[0056] Furthermore, in the above-mentioned method for producing low-cloud-point lubricating oil base oil, the operating conditions (adsorption reaction) of reactor C in the second reaction zone in step (4) are as follows: temperature 40℃~250℃, preferably 60℃~200℃, pressure 0.01MPa~0.5MPa, preferably 0.08~0.1MPa, and volume hourly space velocity 0.05h⁻¹. -1 ~5.0h -1 Preferably 0.1h -1 ~2.0h -1 .

[0057] Furthermore, in the above-mentioned method for producing low-cloud-point lubricating oil base oil, the operating conditions (isomeric pour point depletion reaction) of reactor C in the second reaction zone in step (5) are as follows: reaction temperature is 200–420℃, preferably 270–380℃; reaction pressure is 1.0–20.0 MPa, preferably 3.0–15.0 MPa; and volume hourly space velocity is 0.1–10.0 h⁻¹. -1 Preferably, it is 0.5 to 3.0 h. -1 The hydrogen-to-oil volume ratio is 100:1 to 1500:1, preferably 100:1 to 400:1.

[0058] Furthermore, in the above-mentioned method for producing low-cloud-point lubricating oil base oil, the operating conditions (adsorption reaction) of reactor D in the second reaction zone in step (5) are as follows: temperature 40℃~250℃, preferably 60℃~200℃, pressure 0.01MPa~0.5MPa, preferably 0.08~0.1MPa, and volume hourly space velocity 0.05h⁻¹. -1 ~5.0h -1 Preferably 0.1h -1 ~2.0h -1 .

[0059] Furthermore, in the above-mentioned method for producing low-cloud-point lubricating oil base oil, the operating conditions (isomeric pour point depletion reaction) of reactor D in the second reaction zone in step (4) are as follows: reaction temperature is 200–420℃, preferably 270–380℃; reaction pressure is 1.0–20.0 MPa, preferably 3.0–15.0 MPa; and volume hourly space velocity is 0.1–10.0 h⁻¹. -1 Preferably, it is 0.5 to 3.0 h. -1 The hydrogen-to-oil volume ratio is 100:1 to 1500:1, preferably 100:1 to 400:1.

[0060] A second aspect of the present invention provides a production system for low cloud point lubricating oil base oil, comprising:

[0061] The first reaction zone is used to receive raw materials. The first reaction zone includes reactors A and B connected in parallel. Reactors A and B are used interchangeably. The raw materials first enter reactor A in the first reaction zone and are treated by contacting the adsorbent to obtain the first feed stream. When the refractive index (20°C) of the first feed stream is 0.1% to 5%, preferably 0.5% to 2.5%, higher than the refractive index (20°C) of the raw materials, the raw materials are stopped from entering reactor A in the first reaction zone, and the raw materials are switched to enter reactor B, which is connected in parallel with reactor A. Hydrogen gas is introduced into reactor A, and an isomerization-decondensation reaction occurs under the action of the adsorbent to obtain the isomerization-decondensation reaction product.

[0062] The hydrorefining reaction zone is used to receive hydrogen and the first feed stream from the first reaction zone, which react with the hydrorefining catalyst to obtain the hydrorefining reaction product.

[0063] The first separation zone includes a first gas-liquid separator and a first fractionation tower. The hydrorefining reaction products are separated by the first gas-liquid separator to obtain a first gas phase stream and a first liquid phase stream. The first liquid phase stream enters the first fractionation tower and is separated to obtain light white oil, industrial white oil and rubber filler oil.

[0064] The isomeric pour point depressing gas-liquid separation zone is used to receive the isomeric pour point depressing reaction products from the first reaction zone, and after gas-liquid separation, the third gas phase feed stream and the isomeric pour point depressing oil are obtained.

[0065] The second reaction zone is used to receive isomeric pour point depressed oil. The second reaction zone includes reactors C and D connected in parallel. Reactors C and D are used interchangeably. The isomeric pour point depressed oil first enters reactor C in the second reaction zone and is treated by contacting the adsorbent. After treatment, a second feed stream is obtained. When the refractive index (20°C) of the second feed stream is 0.1% to 3%, preferably 0.3% to 2%, higher than the refractive index (20°C) of the isomeric pour point depressed oil, the flow of the isomeric pour point depressed oil into reactor C in the second reaction zone is stopped. The isomeric pour point depressed oil is then switched to reactor D, which is connected in parallel with reactor C. Hydrogen gas is introduced into reactor C, and an isomeric pour point depressed reaction occurs under the action of the adsorbent, yielding the isomeric pour point depressed reaction product.

[0066] The second gas-liquid separator is used to receive the isomeric decondensation reaction products from the second reaction zone, and after gas-liquid separation, a second gas phase material stream and a second liquid phase material stream are obtained.

[0067] The second fractionation tower receives the second feed stream from the second reaction zone and the second liquid feed stream from the second gas-liquid separator, and after separation, obtains light lubricating oil base oil, medium lubricating oil base oil and heavy lubricating oil base oil products.

[0068] Furthermore, in the aforementioned low-cloud-point lubricating oil base oil production system, reactors A and B in the first reaction zone are connected in parallel and can be switched according to actual production process needs to ensure continuous operation of the entire unit. Reactors A and B are preferably identical and filled with the same adsorbent. Reactors A and B can be one or more of existing fixed-bed reactors, fluidized-bed reactors, and slurry-bed reactors, with fixed-bed reactors being preferred.

[0069] Furthermore, in the production system of the aforementioned low-cloud-point lubricating oil base oil, the hydrorefining reaction zone is equipped with one or more reactors. The reactor can be selected from at least one of fixed-bed reactors, fluidized-bed reactors, boiling-bed reactors, and slurry-bed reactors, with a fixed-bed reactor being preferred.

[0070] Furthermore, in the aforementioned low-cloud-point lubricating oil base oil production system, reactors C and D in the second reaction zone are connected in parallel and can be switched according to actual production process needs to ensure continuous operation of the entire unit. Reactors C and D are preferably identical and filled with the same adsorbent. Reactors C and D can be one or more of existing fixed-bed reactors, fluidized-bed reactors, and slurry-bed reactors, with fixed-bed reactors being preferred.

[0071] Furthermore, in the aforementioned system for producing high viscosity index lubricating oil base oil, the first gas phase material, the third gas phase material stream, and the second gas phase material stream obtained by the first gas-liquid separator, the heterogeneous pour point depressing gas-liquid separation zone, and the second gas-liquid separator are purified and then connected to the first reaction zone, the second reaction zone, and the hydrorefining reaction zone via pipelines for recycling as circulating hydrogen.

[0072] Compared with the prior art, the production method and system for low cloud point lubricating oil base oil provided by the present invention have the following advantages:

[0073] 1. The method provided by this invention pre-treats the raw materials by adsorption, separating non-ideal components and ensuring that only raw materials rich in ideal components such as long-chain isoalkanes, long-side-chain monocyclic cycloalkanes, and long-chain monocyclic aromatics undergo isomerization and dewaxing reactions. This results in the production of high viscosity index lubricating oil base oil products, significantly reducing the participation of non-ideal components in the hydrogenation reaction. This reduces the isomerization and dewaxing processing load, decreases hydrogen consumption, and improves the economic efficiency of the equipment. Furthermore, the applicant discovered during the research process that adding type 5A molecular sieves to the currently used hydroisomerization dewaxing catalyst has a selective adsorption effect on the raw materials of lubricating oil base oil under the condition of no hydrogen presence. This can separate low viscosity index non-ideal components such as bicyclic or higher-ring cycloalkanes and some aromatics from the raw materials, thereby reducing the content of low viscosity index components in the lubricating oil base oil products and increasing the viscosity index of the lubricating oil base oil products.

[0074] 2. The molecular sieve composition provided by this invention is composed of 5A-type molecular sieves and TON-structured molecular sieves interlocked. The 5A-type molecular sieve possesses excellent adsorption capabilities and can enrich alkanes, while the TON-structured molecular sieve has a specific pore structure and suitable acidity, which is beneficial for the selective isomerization of alkanes. The molecular sieve composition provided by this invention combines both of these specific functions and maintains good adsorption performance even after loading with an active metal. Catalysts prepared using the molecular sieve composition provided by this invention, after isomerization and regeneration, still maintain good stability.

[0075] 3. In the lubricating oil base oil production method provided by the present invention, the adsorption separation efficiency is characterized by the change in the refractive index of the raw material before and after adsorption treatment. This parameter is simple and convenient to measure and can intuitively reflect the separation effect of ideal components such as long-chain isoalkanes, long side-chain monocyclic cycloalkanes and long-chain monocyclic aromatics in the raw material.

[0076] 4. The lubricating oil base oil production method provided by the present invention utilizes a catalyst that simultaneously possesses the selective adsorption capacity for long-chain isoalkanes, long-side-chain monocyclic cycloalkanes, and long-chain monocyclic aromatics, as well as the ability to selectively isomerize alkanes in the presence of hydrogen and under suitable reaction conditions. This simplifies the production process of high viscosity index lubricating oil base oil, reduces equipment investment, and lowers process hydrogen consumption. Attached Figure Description

[0077] Figure 1 This is a schematic flowchart of the low-cloud-point lubricating oil base oil production method of the present invention. Detailed Implementation

[0078] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The following embodiments will further illustrate the method provided by the present invention, but do not limit the scope of the invention.

[0079] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0080] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “over,” “up,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0081] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0082] In this document, all numeric values ​​of parameters (e.g., quantity or condition) should be understood to be modified by the term “about” in all cases, regardless of whether “about” actually appears before the numeric value.

[0083] In the context of this specification, unless explicitly stated otherwise, both the silicon-aluminum material and the catalyst undergo calcination treatment, sometimes referred to as "calcination form," prior to measurement. The conditions for this calcination treatment include: calcination at 600°C in an air atmosphere for a calcination time of 3 hours or more.

[0084] In the context of this specification, long side-chain hydrocarbons specifically refer to one or more of long side-chain isoalkanes, long side-chain monocyclic cycloalkanes, and long side-chain monocyclic aromatics, excluding other hydrocarbons with long side chains. Furthermore, according to the present invention, a long side chain refers to a straight-chain alkyl group of C8-22 (preferably C10-18) as the side chain.

[0085] In the context of this specification, a mechanical mixture refers to a mixture of two or more materials obtained by mechanical mixing. Here, mechanical mixing includes simple mixing, grinding, pulping, etc.

[0086] In the context of this specification, an embedded molecular sieve refers to a composite crystal in which one or more molecular sieve crystals are embedded on or within their surface, exhibiting structural characteristics of two or more molecular sieves. Compared to mechanical mixtures, the different molecular sieves are more tightly bound in an embedded structure, truly forming an integrated composite structure at the molecular level.

[0087] In the context of this specification, the refractive index was characterized using a Mettler R5 refractometer, the long-chain hydrocarbon content was characterized using an Agilent GC 7890, the XRD patterns of the samples were characterized using a D / max-2500 fully automated rotating target X-ray diffractometer, the specific surface area, pore volume, and average pore size of the embedded molecular sieves and the specific surface area, pore volume, and average pore size of the catalyst were characterized using an ASAP 2405 physical adsorption instrument via N2 adsorption-desorption, and the calcium content of the calcium-type molecular sieves was characterized using X-ray fluorescence diffraction.

[0088] In the context of this specification, the content of TON structured molecular sieves in the embedded molecular sieves is quantitatively analyzed by XRD determination.

[0089] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, pressure is gauge pressure, and weight or content is on a dry basis.

[0090] like Figure 1As shown, the specific process of the production method of low cloud point lubricating oil base oil provided by the present invention is as follows: Raw material 1 first enters the first reaction zone, which includes reactors A2 and B3 connected in parallel. Reactors A2 and B3 are used interchangeably. Raw material 1 first enters reactor A2 in the first reaction zone and is treated by contacting the catalyst, resulting in feed stream 4. Feed stream 4 and hydrogen 33 enter the hydrorefining reaction zone 6 and react with the hydrorefining catalyst to obtain hydrorefining reaction product 7. Hydrorefining reaction product 7 enters the first gas-liquid separator 8 for separation to obtain the first gas phase feed stream 9 and the first liquid phase feed stream 10. The first liquid phase feed stream 10 enters the first fractionation tower 11 for separation to obtain light white oil and industrial grade oil. Industrial white oil and rubber filler oil; when the refractive index (20℃) of the first feed stream 4 is 0.1% to 5%, preferably 0.3% to 2.5%, higher than the refractive index (20℃) of the raw material 1, the feed material 1 is stopped from entering reactor A2 in the first reaction zone, and the feed material 1 is switched to enter reactor B3 connected in parallel with reactor A2, where it is treated in contact with the catalyst, and the treated product is feed stream 5; feed stream 5 and hydrogen 33 enter the hydrorefining reaction zone 6, where they react in contact with the hydrorefining catalyst to obtain hydrorefining reaction product 7; hydrorefining reaction product 7 enters the first gas-liquid separator 8 for separation to obtain the first gas phase feed stream 9 and the first liquid phase feed stream 10, and the first liquid phase feed stream 10 enters the first fractionation tower 11 for separation to obtain light white oil, Industrial white oil and rubber filler oil are processed. Hydrogen gas 33 is introduced into reactor A2, where an isomerization-depletion reaction occurs under the action of an adsorbent, yielding isomerization-depletion reaction product 15. Product 15 enters the isomerization-depletion gas-liquid separation zone 17 for separation, yielding a third gas phase stream 18 and isomerization-depletion oil 19. Isomerization-depletion oil 19 enters the second reaction zone, which includes reactors C20 and D21 connected in parallel. Reactors C20 and D21 are used interchangeably. Isomerization-depletion oil 19 first enters reactor C20 in the second reaction zone, where it is treated by contacting the catalyst. The resulting stream 22 enters the second fractionation tower 29, where it is separated to obtain light lubricating oil base oil, medium lubricating oil base oil, and... Heavy lubricating oil base oil products; when the refractive index (20℃) of the feed stream 22 is 0.1% to 3% higher than that of the isomerized pour point depressant 19 (20℃), preferably 0.3% to 2.0% higher, the isomerized pour point depressant 19 is stopped from entering the reactor C20 in the second reaction zone, and hydrogen is introduced into the reactor C20. Under the action of the adsorbent, the isomerization pour point depressant reaction reaction occurs, and the isomerization pour point depressant reaction product 24 is obtained. The isomerization pour point depressant reaction product 24 enters the second gas-liquid separator 26. After gas-liquid separation, the second gas phase feed stream 27 and the second liquid phase feed stream 28 are obtained. The second liquid phase feed stream 28 is mixed with the feed stream 22 and enters the second fractionation tower 29. After separation, light lubricating oil base oil, medium lubricating oil base oil and heavy lubricating oil base oil products are obtained.The isomerized pour point depressant 19 is switched to reactor D21, which is connected in parallel with reactor C20, and treated by contact with the adsorbent. The resulting feed stream 23 enters the second fractionation tower 29, where it is separated to obtain lubricating oil base oil products. When the refractive index (20°C) of feed stream 23 is 0.1% to 3%, preferably 0.3% to 2.0%, higher than that of isomerized pour point depressant 19, the flow of isomerized pour point depressant 19 into reactor D21 in the second reaction zone is stopped, and hydrogen is introduced into reactor D21. Under the action of the adsorbent, an isomerization and pour point depressant reaction occurs, yielding isomerization and pour point depressant reaction product 25. The isomerization and pour point depressant reaction product 25 enters the second gas-liquid separator 26, where it is separated to obtain a second gas phase feed stream 27 and a second liquid phase feed stream 28. The second liquid phase feed stream 28 is mixed with feed stream 22 and enters the second fractionation tower 29, where it is separated to obtain light lubricating oil base oil, medium lubricating oil base oil, and heavy lubricating oil base oil products.

[0091] The properties of the feedstock oils used in the embodiments and comparative examples of the present invention are shown in Table 1. The hydrorefining catalysts involved in Examples 1-3 and the comparative examples can be selected from commercial catalysts according to their properties, or they can be prepared according to knowledge in the art. In the method of the present invention, the hydrorefining catalyst used is the FMTA-2 hydrorefining catalyst developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd.

[0092] Table 1 Properties of Crude Oil

[0093]

[0094] In this invention, the catalyst used was prepared by the following method, and the properties of the obtained catalyst are shown in Table 3.

[0095] Example 1

[0096] Preparation of catalyst CAT-1:

[0097] 128g sodium hydroxide, 208g tetraethyl orthosilicate, 82g sodium aluminate, 14.88g dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC), and 1800g water were mixed evenly and placed into a crystallization reactor. Then, 300g of ZSM-22 molecular sieve was added and stirred. The reactor was sealed, and the temperature was raised to 110℃ for hydrothermal crystallization for 6 hours. After crystallization, the crystallized product was washed, dried at 110℃ for 6 hours, and then calcined at 500℃ for 5 hours to obtain the first embedded molecular sieve Z2. Molecular sieve Z2 was then subjected to ion exchange in a 1.8mol / L CaCl2 solution at 90℃ for 4 hours, filtered and washed, dried at 100℃ for 4 hours, and then calcined at 400℃ for 3 hours to obtain the second embedded molecular sieve GZ-1, with a specific surface area of ​​452 m². 2 / g, pore volume is 0.25mL / g, and the mass fraction of TON structured molecular sieve is 85%.

[0098] 210g of the eutectic molecular sieve GZ-1 prepared above was thoroughly mixed with 90g of pseudoboehmite (dry basis) and 20g of guar gum powder. 9ml of concentrated nitric acid (65% by mass) and an appropriate amount of water were added, and the mixture was thoroughly kneaded and then extruded into strips. The shaped support was dried at 100℃ for 4h and calcined at 550℃ for 4h to obtain support ES-1. Then, noble metal Pt was impregnated using a saturated impregnation method, with a Pt loading of 0.50wt% of the support. After drying at 100℃ for 6h and calcining at 500℃ for 3h, the catalyst of this invention, designated CAT-1, was obtained.

[0099] Example 2

[0100] Preparation of catalyst CAT-2

[0101] 64g sodium hydroxide, 208g tetraethyl orthosilicate, 98.4g sodium aluminate, 24.8g dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC), and 2700g water were mixed evenly and placed into a crystallization vessel. Then, 240g of ZSM-22 molecular sieve was added and stirred. The vessel was sealed, and the temperature was raised to 100℃ for hydrothermal crystallization for 7 hours. After crystallization, the product was washed, dried at 100℃ for 6 hours, and then calcined at 450℃ for 8 hours to obtain the first embedded molecular sieve Z6. Then, molecular sieve Z6 was subjected to ion exchange in a 1.5 mol / L CaCl2 solution at 80℃ for 4 h, filtered and washed, dried at 100℃ for 5 h, and then calcined at 350℃ for 6 h to obtain the second embedded molecular sieve GZ-2, which has a specific surface area of ​​498 m2 / g, a pore volume of 0.23 mL / g, and a TON structure molecular sieve mass fraction of 82%.

[0102] The preparation process of the catalyst CAT-2 of the present invention is the same as that in Example 1, except that the embedded molecular sieve used is GZ-2 and the Pt loading is 0.48 wt% of the support, thus preparing the catalyst CAT-2 of the present invention.

[0103] Example 3

[0104] Preparation of catalyst CAT-3

[0105] 80g sodium hydroxide, 184g sodium silicate, 65.6g sodium aluminate, 4.96g dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC), and 540g water were mixed evenly and placed into a crystallization vessel. Then, 42g of ZSM-22 molecular sieve was added and stirred. The vessel was sealed, and the temperature was raised to 120℃ for hydrothermal crystallization for 5 hours. After crystallization, the product was washed, dried at 120℃ for 5 hours, and then calcined at 500℃ for 4 hours to obtain the first embedded molecular sieve Z3. Then, molecular sieve Z3 was subjected to ion exchange in a 1.2 mol / L CaCl2 solution at 70℃ for 6 h, filtered and washed, dried at 100℃ for 4 h, and then calcined at 450℃ for 3 h to obtain the second embedded molecular sieve GZ-3, which has a specific surface area of ​​573 m2 / g, a pore volume of 0.19 mL / g, and a TON structure molecular sieve mass fraction of 47%.

[0106] The preparation process of catalyst 3 of the present invention is the same as that in Example 1, except that the embedded molecular sieve used is GZ-3, the Pt loading is 0.31 wt% of the support, and the catalyst CAT-3 of the present invention is prepared.

[0107] Table 2 Physicochemical properties of catalysts

[0108]

[0109] Example 4

[0110] Example 4 uses the feedstock oils listed in Table 1. Figure 1 The process flow described above uses catalyst CAT-1 in both the first and second reaction zones. The process conditions are shown in Table 3.

[0111] Example 5

[0112] Example 5 uses the feedstock oils listed in Table 1. Figure 1 The process flow described above uses CAT-2 catalyst in both the first and second reaction zones. The process conditions are shown in Table 3.

[0113] Example 6

[0114] Example 4 uses the feedstock oils listed in Table 1. Figure 1 The process flow described above uses CAT-3 catalyst in both the first and second reaction zones. The process conditions are shown in Table 3.

[0115] Comparative Example 1

[0116] Take 134g of ZSM-22 molecular sieve (silicon-to-aluminum ratio 90), 200g of 5A molecular sieve, 150g of aluminum hydroxide (SB produced by Condean GmbH, Germany) and 30g of guar gum powder and mix them evenly. Then add water and concentrated nitric acid (mass concentration of 66.5wt%) and knead thoroughly to make a paste-like plastic material. Extrude cylindrical strips with a diameter of 1.5mm on an extruder. Dry the cylindrical strips at 100℃ for 12 hours and then calcine them at 550℃ in air for 4 hours to obtain the catalyst support of the present invention.

[0117] The precious metal Pt was loaded onto 300 g of support using a saturated impregnation method, then dried at 110 °C for 7 hours and calcined at 500 °C for 3 hours in air atmosphere to obtain the catalyst of this invention containing 0.49 wt% Pt, designated as C-D1.

[0118] Comparative Example 2

[0119] 40g sodium hydroxide, 208g tetraethyl orthosilicate, 285.6g aluminum isopropoxide, 5.75g polyethylene oxide triblock copolymer (P123), and 1440g water were mixed evenly and placed into a crystallization vessel. Then, 60g Hβ molecular sieve was added and stirred. The vessel was sealed, and the temperature was raised to 90℃ for hydrothermal crystallization for 10 hours. After crystallization, the crystallized product was washed, dried at 110℃ for 6 hours, and then calcined at 450℃ for 8 hours to obtain the first mosaic molecular sieve. The molecular sieve was then subjected to ion exchange in a 1.8mol / L CaCl2 solution at 90℃ for 4 hours, filtered and washed, dried at 100℃ for 4 hours, and then calcined at 400℃ for 3 hours to obtain the second mosaic molecular sieve D.

[0120] The preparation process of the comparative catalyst C-D2 in this invention is the same as that in Example 1, except that the embedded molecular sieve D is used and the Pt loading is 0.30 wt% of the support. The resulting catalyst is designated as C-D2.

[0121] Comparative Example 3

[0122] Comparative Example 3 used the feedstock oils listed in Table 1. Figure 1 The process flow described above uses catalyst C-D1 in both the first and second reaction zones. The process conditions are shown in Table 3.

[0123] Comparative Example 4

[0124] Comparative Example 4 used the feedstock oils listed in Table 1. Figure 1 The process flow described above uses catalyst C-D2 in both the first and second reaction zones. The process conditions are shown in Table 3.

[0125] Table 3. Process conditions and results of the examples and comparative examples

[0126] Example number Example 4 Example 5 Example 6 Comparative Example 3 Comparative Example 4 Adsorption reaction process conditions in the first reaction zone Adsorption temperature / ℃ 120 50 220 120 120 Adsorption pressure / MPa 0.08 0.30 0.04 0.08 0.08 <![CDATA[Space velocity per hour -1 > 1.20 0.06 4.00 1.00 1.00 First material flow refractive index (20℃) 1.4555 1.4914 1.4383 1.4555 1.4555 Isomerization dewaxing process conditions in the first reaction zone Reaction temperature / ℃ 335 400 260 335 335 Reaction pressure / MPa 12.0 2.5 17.5 12.0 12.0 Hydrogen-to-oil volume ratio 300 1200 800 300 300 <![CDATA[Space velocity per hour -1 > 1.00 0.30 4.50 1.00 1.00 Adsorption reaction process conditions in the second reaction zone Adsorption temperature / ℃ 130 55 230 130 130 Adsorption pressure / MPa 0.09 0.40 0.06 0.09 0.09 <![CDATA[Space velocity per hour -1 > 0.90 0.08 4.20 0.90 0.90 Refractive index of the second material flow (20℃) 1.4396 1.4418 1.4368 1.4396 1.4396 Second reaction zone isomerization dewaxing process conditions Reaction temperature / ℃ 330 390 250 330 330 Reaction pressure / MPa 12.0 2.5 17.5 12.0 12.0 Hydrogen-to-oil volume ratio 300 1000 600 300 300 <![CDATA[Space velocity per hour -1 > 1.20 0.40 4.80 1.20 1.20 Hydrorefining reaction zone process conditions Reaction temperature / ℃ 250 190 280 250 250 Reaction pressure / MPa 12.0 2.5 17.5 13.0 13.0 Hydrogen-to-oil volume ratio 600 500 1200 600 600 <![CDATA[Space velocity per hour -1 > 0.80 0.20 5.00 0.80 0.80 Base oil properties Light lubricating oil base oil Pour point / ℃ -35 -32 -27 -20 -15 <![CDATA[Viscosity (100 °C), mm / s 2 > 1.940 1.900 1.980 1.910 2.012 Viscosity Index 112 110 107 104 99 medium-quality lubricating oil base oil Pour point / ℃ -31 -28 -23 -15 -10 <![CDATA[Viscosity (100 °C), mm / s 2 > 3.492 3.650 3.580 3.760 3.680 Viscosity Index 124 122 118 112 105 Heavy lubricating oil base oil Pour point / ℃ -18 -15 -10 -3 0 Cloud point / °C 0 3 7 11 15 <![CDATA[Viscosity (100 °C), mm / s 2 > 10.290 9.710 10.845 9.930 9.965 Viscosity Index 135 132 127 119 111

Claims

1. A method for producing a low-cloud-point lubricating oil base oil, comprising the following steps: (1) a raw material is introduced into a first reaction zone and treated with a catalyst to obtain a first stream; (2) the first stream obtained in step (1) is mixed with hydrogen and introduced into a hydrofining reaction zone to react with a hydrofining catalyst, and the reaction product is separated to obtain light white oil, industrial white oil, and rubber filling oil; (3) when the refractive index at 20°C of the first stream is 0.1% to 5% higher than that of the raw material, the introduction of the raw material into the first reaction zone is stopped, hydrogen is introduced into the first reaction zone, and isomerization and condensation reaction occurs under the action of the catalyst, and the isomerization and condensation reaction product is separated by gas-liquid separation to obtain a gas phase stream and an isomerization and condensation oil; (4) the isomerization and condensation oil from step (3) is introduced into a second reaction zone and treated with a catalyst to obtain a second stream, and the second stream is separated to obtain light lubricating oil base oil, medium lubricating oil base oil, and heavy lubricating oil base oil products; (5) when the refractive index at 20°C of the second stream is 0.1% to 3% higher than that of the isomerization and condensation oil, the introduction of the isomerization and condensation oil into the second reaction zone is stopped, hydrogen is introduced into the second reaction zone, and reaction occurs under the action of the catalyst, and the reaction product is separated by gas-liquid separation to obtain a gas phase stream and a liquid phase stream, and the liquid phase stream is separated together with the second stream; the raw material is selected from one or more of hydrocracking tail oil, hydrotreated VGO, hydrocracked wax paste, and hydrocracked foots oil, and the wax content of the raw material is not less than 60% by weight; the catalyst comprises a mosaic molecular sieve of a TON structure molecular sieve and a 5A molecular sieve, an active metal component, and an inorganic refractory oxide; the active metal component is selected from at least one of the noble metals in Group VIII of the Periodic Table of Elements; The operating conditions of the adsorption reaction in the first reaction zone in step (1) are as follows: temperature 40°C to 250°C, pressure 0.01 MPa to 0.5 MPa, and volume space velocity 0.05 h -1 to 5.0 h -1 ; The operating conditions of the adsorption reaction in the second reaction zone in step (4) are as follows: temperature 40°C to 250°C, pressure 0.01 MPa to 0.5 MPa, volume space velocity 0.05 h -1 ~ 5.0 h -1 .

2. The method for producing a low-cloud-point lubricating oil base oil according to claim 1, characterized by: when the refractive index at 20°C of the first stream is 0.5% to 2.5% higher than that of the raw material, the introduction of the raw material into the first reaction zone is stopped, hydrogen is introduced into the first reaction zone, and isomerization and condensation reaction occurs under the action of the catalyst, and the isomerization and condensation reaction product is separated by gas-liquid separation to obtain a gas phase stream and an isomerization and condensation oil.

3. The method for producing a low-cloud-point lubricating oil base oil according to Claim 1, characterized by: when the refractive index at 20°C of the second stream is 0.3% to 2% higher than that of the isomerization and condensation oil, the introduction of the isomerization and condensation oil into the second reaction zone is stopped, hydrogen is introduced into the second reaction zone, and reaction occurs under the action of the catalyst, and the reaction product is separated by gas-liquid separation to obtain a gas phase stream and a liquid phase stream, and the liquid phase stream is separated together with the second stream.

4. The production process of a low-cloud-point lubricating oil base oil according to Claim 1, characterized by: one or more reactors are provided in the first reaction zone.

5. The method for producing a low-cloud-point lubricating oil base oil according to Claim 1, characterized by: two reactors are provided in the first reaction zone and are denoted as reactor A and reactor B, the two reactors are connected in parallel and used by switching, when the introduction of the raw material into reactor A is stopped, the raw material is switched to enter reactor B connected in parallel with reactor A, and steps (1) to (3) are repeated.

6. The method for producing a low-cloud-point lubricating oil base oil according to claim 1, characterized by: The operating conditions of the adsorption reaction in the first reaction zone in step (1) are as follows: temperature 60-200°C, pressure 0.08-0.1 MPa, volume space velocity 0.1-2.0 h -1 -1 -1 .

7. The method for producing a low-cloud-point lubricating oil base oil according to Claim 1, characterized by: the TON structure molecular sieve is mosaic embedded on at least a part of the surface of the 5A molecular sieve at a predetermined surface coverage, and a suitable surface coverage is 0.5% or more and 50% or less.

8. The method for producing a low-cloud-point lubricating oil base oil according to Claim 1, characterized by: The TON structure molecular sieve is inlaid on at least a part of the surface of the 5A type molecular sieve with a predetermined surface coverage, and a suitable surface coverage is 0.5% or more and 20% or less.

9. The method for producing a low-cloud-point lubricating oil base oil according to Claim 1, characterized by: The TON structure molecular sieve is inlaid on at least a part of the surface of the 5A type molecular sieve with a predetermined surface coverage, and a suitable surface coverage is 1% or more and 50% or less.

10. The method for producing a low-cloud-point lubricating oil base oil according to Claim 1, characterized by: The TON structure molecular sieve is inlaid on at least a part of the surface of the 5A type molecular sieve with a predetermined surface coverage, and a suitable surface coverage is 1% or more and 20% or less.

11. The method for producing a low-cloud-point lubricating oil base oil according to claim 1, characterized by: The specific surface area of the catalyst is 200 m 2 / g to 550 m 2 / g, and the pore volume is 0.25 cm 3 / g to 0.60 cm 3 / g.

12. The method for producing a low-cloud-point lubricating oil base oil according to claim 1, characterized by: The content of the inlaid molecular sieve is 10wt%-90wt% based on 100wt% of the total weight of the catalyst, and the content of the active metal component is 0.05wt%-5.0wt% based on the metal element.

13. The method for producing a low-cloud-point lubricating oil base oil according to claim 1, characterized by: The content of the inlaid molecular sieve is 20wt%-70wt% based on 100wt% of the total weight of the catalyst, and the content of the active metal component is 0.1wt%-1.0wt% based on the metal element.

14. The method for producing a low-cloud-point lubricating oil base oil according to claim 1, characterized by: The inorganic refractory oxide is selected from one or more of alumina, titania, boria, silica, zirconia and magnesia.

15. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The inorganic refractory oxide is alumina.

16. The method for producing a low-cloud-point lubricating oil base oil according to claim 1, characterized by: The active metal component is selected from at least one of Pt and Pd.

17. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The active metal component is Pt.

18. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The TON structure molecular sieve is selected from one or more of ZSM-22, Theta-1, ISI-1, KZ-2 and NU-10, and the 5A type molecular sieve is selected from 5A molecular sieve.

19. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The TON structure molecular sieve is ZSM-22, and the 5A type molecular sieve is selected from 5A molecular sieve.

20. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The operating conditions of the hydrofining reaction zone are as follows: reaction temperature 180°C to 300°C, hydrogen partial pressure 2.0 MPa to 18.0 MPa, volume space velocity 0.2 h -1 ~ 6.0 h -1 , hydrogen to oil volume ratio 400: 1 to 1500:

1.

21. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The operating conditions of the hydrofining reaction zone are as follows: reaction temperature 200-260°C, hydrogen partial pressure 10.0-15.0 MPa, volume space velocity 0.3-1.8 h -1 -1 , hydrogen to oil volume ratio 600:1-800:1.​ 22. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The operating conditions of the isomerization and depressurization reaction in the first reaction zone in step (3) are as follows: the reaction temperature is 200°C-420°C, the reaction pressure is 1.0 MPa-20.0 MPa, the volume space velocity is 0.1 h -1 -10.0 h -1 , and the volume ratio of hydrogen to oil is 100:1-1500:

1.

23. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The operating conditions of the isomerization and dewaxing reaction in the first reaction zone in step (3) are as follows: the reaction temperature is 270-380°C, the reaction pressure is 3.0-15.0 MPa, the volume space velocity is 0.5-3.0 h -1 , the volume ratio of hydrogen to oil is 100:1-400:

1. -1 , the volume ratio of hydrogen to oil is 100:1-400:

1.

24. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The second reaction zone is provided with one or more reactors.

25. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The second reaction zone is provided with two reactors, which are respectively denoted as reactor C and reactor D, and the two reactors are connected in parallel and used by switching, when the isomerization and condensation-reducing oil is stopped from entering the reactor C, the isomerization and condensation-reducing oil is switched to enter the reactor D connected in parallel with the reactor C, and steps (4) and (5) are repeated.

26. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The operating conditions of the adsorption reaction in the second reaction zone in step (4) are as follows: temperature 60-200°C, pressure 0.08-0.1 MPa, volume space velocity 0.1-2.0 h -1 -1 .​ 27. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The operating conditions of the isomerization and condensation reaction in the second reaction zone in step (5) are as follows: the reaction temperature is 200°C-420°C, the reaction pressure is 1.0 MPa-20.0 MPa, the volume space velocity is 0.1 h -1 -10.0 h -1 , and the volume ratio of hydrogen to oil is 100:1-1500:

1.

28. The method of producing a low cloud point lubricating oil base oil according to claim 1, characterized by: The operating conditions of the isomerization and condensation reaction in the second reaction zone in step (5) are as follows: the reaction temperature is 270-380°C, the reaction pressure is 3.0-15.0 MPa, the volume space velocity is 0.5-3.0 h -1 , and the volume ratio of hydrogen to oil is 100:1-400:

1. -1 ​ 29. A production system for producing a low-haze lubricating oil base oil according to any one of claims 1-28, comprising: a first reaction zone for receiving a raw material, the first reaction zone comprising reactors A and B connected in parallel, the reactors A and B being used by switching, the raw material being first introduced into the reactor A in the first reaction zone, and being treated by contacting with an adsorbent to obtain a first stream; when the refractive index at 20°C of the first stream is 0.1%-5% higher than that of the raw material, the raw material is switched to be introduced into the reactor B connected in parallel with the reactor A; and hydrogen is introduced into the reactor A to cause isomerization and condensation-reduction reaction under the action of the adsorbent to obtain an isomerization and condensation-reduction reaction product; a hydrofining reaction zone for receiving hydrogen and the first stream from the first reaction zone, and reacting with a hydrofining catalyst to obtain a hydrofining reaction product; The inorganic refractory oxide is selected from one or more of alumina, titania, boria, silica, zirconia and magnesia. The inorganic refractory oxide is alumina. The active metal component is selected from at least one of Pt and Pd. The active metal component is Pt. The TON structure molecular sieve is selected from one or more of ZSM-22, Theta-1, ISI-1, KZ-2 and NU-10, and the 5A type molecular sieve is selected from 5A molecular sieve. The TON structure molecular sieve is ZSM-22, and the 5A type molecular sieve is selected from 5A molecular sieve. The second reaction zone is provided with one or more reactors. The second reaction zone is provided with two reactors, which are respectively denoted as reactor C and reactor D, and the two reactors are connected in parallel and used by switching, when the isomerization and condensation-reducing oil is stopped from entering the reactor C, the isomerization and condensation-reducing oil is switched to enter the reactor D connected in parallel with the reactor C, and steps (4) and (5) are repeated.

29. A production system for producing a low-haze lubricating oil base oil according to any one of claims 1-28, comprising: a first reaction zone for receiving a raw material, the first reaction zone comprising reactors A and B connected in parallel, the reactors A and B being used by switching, the raw material being first introduced into the reactor A in the first reaction zone, and being treated by contacting with an adsorbent to obtain a first stream; when the refractive index at 20°C of the first stream is 0.1%-5% higher than that of the raw material, the raw material is switched to be introduced into the reactor B connected in parallel with the reactor A; and hydrogen is introduced into the reactor A to cause isomerization and condensation-reduction reaction under the action of the adsorbent to obtain an isomerization and condensation-reduction reaction product; a hydrofining reaction zone for receiving hydrogen and the first stream from the first reaction zone, and reacting with a hydrofining catalyst to obtain a hydrofining reaction product; The first separation zone comprises a first gas-liquid separator and a first fractionating column. The first gas-liquid separator is used to separate the hydrogenation product to obtain a first gas phase stream and a first liquid phase stream. The first liquid phase stream is introduced into the first fractionating column to obtain light white oil, industrial white oil and rubber filling oil. The isomerization and pour point depressing gas-liquid separation zone is used to receive the isomerization and pour point depressing reaction product from the first reaction zone. The isomerization and pour point depressing gas-liquid separation zone is used to separate the isomerization and pour point depressing reaction product to obtain a third gas phase stream and isomerization and pour point depressing oil. The second reaction zone is used to receive the isomerization and pour point depressing oil. The second reaction zone comprises reactors C and D connected in parallel. The reactors C and D are switched to use. The isomerization and pour point depressing oil is first introduced into the reactor C in the second reaction zone to contact with the adsorbent for treatment. The second stream is obtained after the treatment. When the 20℃ refractive index of the second stream is 0.1% to 3% higher than the 20℃ refractive index of the isomerization and pour point depressing oil, the isomerization and pour point depressing oil is stopped from being introduced into the reactor C in the second reaction zone. The isomerization and pour point depressing oil is switched to be introduced into the reactor D connected in parallel with the reactor C. Hydrogen is introduced into the reactor C. The isomerization and pour point depressing reaction occurs under the action of the adsorbent to obtain the isomerization and pour point depressing reaction product. The second gas-liquid separator is used to receive the isomerization and pour point depressing reaction product from the second reaction zone. The second gas-liquid separator is used to separate the isomerization and pour point depressing reaction product to obtain a second gas phase stream and a second liquid phase stream. The second fractionating column is used to receive the second stream from the second reaction zone and the second liquid phase stream from the second gas-liquid separator. The second fractionating column is used to separate the second stream and the second liquid phase stream to obtain light lubricating oil base oil, medium lubricating oil base oil and heavy lubricating oil base oil products.

30. The production system of claim 29, wherein: When the 20℃ refractive index of the first stream is 0.5% to 2.5% higher than the 20℃ refractive index of the raw material, the raw material is stopped from being introduced into the reactor A in the first reaction zone. The raw material is switched to be introduced into the reactor B connected in parallel with the reactor A. Hydrogen is introduced into the reactor A. The isomerization and pour point depressing reaction occurs under the action of the adsorbent to obtain the isomerization and pour point depressing reaction product.

31. The production system of claim 29, wherein: When the 20℃ refractive index of the second stream is 0.3% to 2% higher than the 20℃ refractive index of the isomerization and pour point depressing oil, the isomerization and pour point depressing oil is stopped from being introduced into the reactor C in the second reaction zone. The isomerization and pour point depressing oil is switched to be introduced into the reactor D connected in parallel with the reactor C. Hydrogen is introduced into the reactor C. The isomerization and pour point depressing reaction occurs under the action of the adsorbent to obtain the isomerization and pour point depressing reaction product.

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