A method and system for hydroregenerating spent lubricating oil

Abstract

The present disclosure relates to a method and system for hydrogenation regeneration of waste lubricating oil, which comprises: S1, contacting the waste lubricating oil with an oil-soluble catalyst in a slurry bed for hydrogenation pretreatment to obtain a hydrogenation mixture; S2, fractionating the hydrogenation mixture to obtain a gas, a distillate oil and a catalyst-containing tail oil; S3, introducing part of the catalyst-containing tail oil into the slurry bed; the remaining part of the catalyst-containing tail oil is discharged; and S4, contacting the distillate oil with a catalyst in a high-pressure fixed-bed hydrogenation device for high-pressure hydrogenation reaction. The method of the present disclosure can effectively remove metal and non-metallic heteroatoms in the waste lubricating oil, reduce the severity of the subsequent processing process, and obtain high-quality lubricating oil base oil.

Description

Technical Field

[0001] This invention relates to a method and system for hydrogenating and regenerating waste lubricating oil. Background Technology

[0002] Waste lubricating oil refers to the oil that has been replaced during the use of various machines and equipment due to oxidation, thermal decomposition, and contamination by impurities, resulting in its physicochemical properties reaching the required replacement levels. Recycling waste lubricating oil not only conserves petroleum resources but also reduces environmental pollution.

[0003] The development of waste lubricating oil regeneration processes has generally gone through stages such as sulfuric acid-clay process, distillation-clay process, and distillation-hydrogenation. The biggest drawback of traditional waste lubricating oil recycling technologies is that the waste generated during the recycling process can easily cause environmental pollution. Currently, many oil companies at home and abroad are researching and developing new waste lubricating oil hydrogenation recovery technologies. To date, representative technologies include distillation-solvent refining-hydrogenation refining, demetallization-fixed bed hydrogenation refining, and distillation-hydrogenation refining.

[0004] In recent years, various mechanical equipment has placed increasingly higher demands on the performance of lubricating oil products. To meet the stringent operating conditions of these machines, manufacturers are adding more and more additives to their finished lubricating oils. However, these additives often contain heavy metal compounds, which can easily deposit on the surface of the hydrogenation catalyst during the hydrogenation reaction, causing rapid catalyst poisoning, deactivation, and shortened lifespan. Furthermore, they can deposit on the outer surface of catalyst particles or accumulate between particles, leading to catalyst bed agglomeration and blockage, resulting in a rapid increase in reactor pressure drop and shutdown. Therefore, effectively removing heavy metals, avoiding their impact on the catalyst and equipment, and ensuring stable, long-term operation of the hydrogenation process are key challenges in waste lubricating oil regeneration technology.

[0005] CN106398765A proposes a method for the hydrogenation and recycling of waste lubricating oil. This method involves the oil-soluble catalyst passing through only once, resulting in low utilization. Furthermore, the pretreated full-fraction oil is directly fed into subsequent hydrogenation and reforming before being cut into various products. This reduces the residence time of the target components in the base oil and leads to poor product color. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for hydrogenating and regenerating waste lubricating oil. The method disclosed herein can effectively remove metal and non-metal heteroatoms from waste lubricating oil and saturate some polycyclic aromatic hydrocarbons, thereby reducing the severity of subsequent processing and enabling the preparation of high-quality lubricating oil base oil.

[0007] To achieve the above objectives, the first aspect of this disclosure provides a method for hydrogenating and regenerating waste lubricating oil, the method comprising:

[0008] S1. The waste lubricating oil is contacted with the oil-soluble catalyst in a slurry bed for hydrogenation pretreatment to obtain a hydrogenated mixture;

[0009] S2. The hydrogenated mixture is fractionated to obtain gas, distillate oil and catalyst-containing tail oil;

[0010] S3. Introduce a portion of the catalyst-containing tail oil into the slurry bed; discard the remaining portion of the catalyst-containing tail oil.

[0011] In a high-pressure fixed-bed hydrogenation unit, the distillate oil is brought into contact with a hydrogenation catalyst to carry out a high-pressure hydrogenation reaction.

[0012] Optionally, in step S1, the conditions for the hydrogen pretreatment include: a reaction temperature of 300-480℃; a reaction pressure of 2-25 MPa; and a liquid hourly space velocity of 0.2-4 h⁻¹. -1 The volume ratio of hydrogen to the waste lubricating oil is 100-3000 Nm³. 3 / m 3 .

[0013] Optionally, in step S1, the oil-soluble catalyst includes a catalyst main agent and an auxiliary agent; the molar ratio of the catalyst main agent (calculated as metal element) to the auxiliary agent (calculated as sulfur element) in the oil-soluble catalyst is 1:(0.5-5), preferably 1:(0.5-4);

[0014] The additive includes sulfur-containing substances; preferably, the sulfur-containing substances include one or more of carbon disulfide, sulfur, dimethyl disulfide and di-tert-butyl polysulfide.

[0015] The catalyst host comprises a metal central atom or central ion, and an organic ligand coordinated with the metal central atom or central ion; the general formula of the catalyst host is: MO a [R(COOH b ) x ] c ,

[0016] Where M represents a metal, R(COOH) b ) x The organic ligand represents the organic ligand comprising a carboxyl group and a carboxylic acid group; R represents the hydrocarbon group in the organic ligand; x represents the molar ratio of the total number of the carboxyl group and the carboxylic acid group to the hydrocarbon group R; a represents the molar ratio of the noncoordinate bonded oxygen atom connected to the metal M to the metal M; b represents the molar ratio of the carboxylic acid group to the total number of the carboxyl group and the carboxylic acid group; and c represents the molar ratio of the organic ligand to the metal M, wherein:

[0017] The metal is a Group B and / or Group VIII metal with hydrogenation properties;

[0018] x is 1, 2 or 3, preferably 1 or 2;

[0019] a is a positive number from 0 to 5, preferably a positive number from 1 to 3;

[0020] b is a positive number between 0.01 and 0.99, preferably a positive number between 0.1 and 0.5;

[0021] c is a positive number between 0.5 and 10, preferably a positive number between 1 and 5.

[0022] Optionally, in step S1, based on the dry weight of the catalyst main agent, the metal content in the catalyst main agent is 2-40% by weight, preferably 2-35%, preferably 8-30%, and more preferably 10-20%.

[0023] The metal is one or more of Ti, V, Cr, Mo, W, Fe, Co, Ru, Ni, Cu and Zn, preferably one or more of V, Mo, W, Fe, Co, Ni, Cu and Zn, and more preferably one or more of Mo, W, Ni, Co and Fe;

[0024] R is a C3-C19 hydrocarbon group, preferably a C5-C11 normal or isomeric alkyl group, a C5-C12 cycloalkyl group, or a C6-C12 aryl group.

[0025] Optionally, in step S1, the amount of the oil-soluble catalyst, calculated as metal element, relative to 1g of the waste lubricating oil is 20-10000μg, preferably 50-5000μg, and more preferably 100-3000μg.

[0026] Optionally, in step S2, the fractionation conditions include: a pressure of -90 kPa to -99 kPa and a bottom temperature of 320-370°C.

[0027] The distillation range of the distillate oil is 280-540℃, preferably 300-520℃;

[0028] The distillation range of the catalyst-containing tail oil is above 500°C, preferably above 520°C.

[0029] Optionally, in step S3, the amount of catalyst-containing tail oil introduced into the slurry bed accounts for 90-100% by weight of the total amount of catalyst-containing tail oil.

[0030] Optionally, in step S3, along the flow direction of the distillate oil, the hydrogenation catalyst includes a hydrogenation protection catalyst and a hydrogenation treatment catalyst;

[0031] Based on the total volume of the hydrogenation catalyst and by volume, the amount of the hydrogenation protection catalyst is 10-50%, and the amount of the hydrogenation treatment catalyst is 50-90%.

[0032] Optionally, in step S3, along the flow direction of the distillate oil, the hydroprotection catalyst sequentially includes catalyst A, catalyst B, and catalyst C; based on the total volume of the hydroprotection catalyst, the content of catalyst A is 5-20%, the content of catalyst B is 10-50%, and the content of catalyst C is 30-85%.

[0033] The catalyst A contains a first hydrogenation active metal and a first support; the first hydrogenation active metal includes Group VB metals and Group VIB metals, and the first support is selected from alumina and / or silicon oxide; based on the total weight of the catalyst A and calculated as oxides, the content of the Group VB metal is less than 12% by weight, and the content of the Group VIB metal is 0.2-12% by weight; the first support contains phosphorus and halogens, based on the total weight of the first support, the phosphorus content is 0.1-8.0% by weight (calculated as P2O5), and the halogen content is 0.1-6% by weight (calculated as an element).

[0034] The catalyst B contains a second hydrogenation active metal and a second support; the second hydrogenation active metal includes a Group VIB metal and optionally a Group VIII metal, and the second support is selected from alumina and / or silica; based on the total weight of the catalyst B and calculated as oxides, the content of the Group VIB metal is greater than 0 and less than 4% by weight, and the content of the Group VIII metal is 0-0.8% by weight; the second support contains phosphorus and halogens, based on the total weight of the second support, the phosphorus content is 0.1-8.0% by weight (calculated as P2O5), and the halogen content is 0.1-6% by weight (calculated as an element).

[0035] The catalyst C contains a third hydrogenation active metal and a third support; the third hydrogenation active metal includes Group VIII metals and Group VIB metals, and the third support is selected from alumina and / or silica; based on the total weight of the catalyst C and calculated as oxides, the content of the Group VIB metal is 0.2-10% by weight, and the content of the Group VIII metal is less than 5% by weight; the third support contains phosphorus, and based on the total weight of the third support, the phosphorus content calculated as P2O5 is 0.1-8.0% by weight.

[0036] Preferably, the volume ratio of catalyst A, catalyst B and catalyst C is 1:(1-10):(1.5-17), more preferably 1:(2-5):(3-15);

[0037] Along the flow direction of the distillate oil, the hydrotreating catalyst sequentially comprises catalyst I and catalyst II;

[0038] The catalyst I comprises a hydrogenation catalyst Ia, which contains a fourth promoter, a fourth hydrogenation active metal component, and a fourth support; the first promoter comprises one or more of fluorine, boron, and phosphorus; the first hydrogenation active metal comprises one or more of Co, Mo, Ni, and W; the fourth support is selected from alumina and / or silicon oxide; based on the dry weight of the hydrogenation catalyst Ia, the content of the fourth hydrogenation active metal component, calculated as metal oxide, is 16-45% by weight, and the content of the first promoter is 0.5-10% by weight;

[0039] Preferably, the catalyst I further includes a hydrogenation catalyst Ib disposed upstream of the hydrogenation catalyst Ia; the hydrogenation catalyst Ib contains a fifth hydrogenation active metal component and a fifth support, and the content of the fifth hydrogenation active metal component, calculated as metal oxide, is 3-8% by weight based on the dry weight of the hydrogenation catalyst Ib; the fifth hydrogenation active metal component is selected from one or more of Co, Mo, Ni and W; the fifth support is selected from alumina and / or silicon oxide;

[0040] More preferably, the weight content of the fifth hydrogenation active metal component of the hydrogenation catalyst Ib is 10-30% of the weight content of the fourth hydrogenation active metal component of the hydrogenation catalyst Ia, preferably 12-25%; preferably, the volume ratio of the hydrogenation catalyst Ia to the hydrogenation catalyst Ib is (10-50):10.

[0041] The second hydrogenation catalyst further includes a hydrogenation catalyst II disposed downstream of the hydrogenation catalyst I; the hydrogenation catalyst II contains a second promoter, a sixth hydrogenation active metal component, and a sixth support, the second promoter comprising boron and / or phosphorus, and the content of the sixth hydrogenation active metal component, based on the dry weight of the hydrogenation catalyst II and calculated as metal oxide, is 16-52% by weight; the sixth hydrogenation active metal component is selected from one or more of Co, Mo, Ni, and W; the sixth support is selected from alumina; the catalyst II is a fluorine-free hydrogenation catalyst, and the content of the second promoter is 2-8% by weight; the content of the sixth hydrogenation active metal component of the hydrogenation catalyst II is greater than or equal to the total content of the fourth and fifth hydrogenation active metal components of the hydrogenation catalyst I;

[0042] Preferably, the volume ratio of the hydrogenation catalyst I to the hydrogenation catalyst II is (30:70)-(60:40).

[0043] Optionally, in step S3, the conditions for the high-pressure hydrogenation reaction in which the distillate oil contacts the hydrotreating protective catalyst include: a hydrogen partial pressure of 3-20 MPa, a hydrogen-to-oil volume ratio of 200-3000, a reaction temperature of 260-380°C, and a volume hourly space velocity of 0.2-5 h⁻¹. -1 ;

[0044] Preferably, the hydrogen partial pressure is 5-12 MPa, the hydrogen-to-oil volume ratio is 300-1800, the reaction temperature is 280-360℃, and the volume hourly space velocity is 0.3-3 h⁻¹. -1 .

[0045] Optionally, in step S3, the conditions for the high-pressure hydrogenation reaction between the distillate oil and the hydrotreating catalyst include: a hydrogen partial pressure of 3-25 MPa and a hydrogen-to-oil volume ratio of 200-3000; wherein the reaction temperature of catalyst I is 260-420°C and the volume hourly space velocity is 0.2-3 h⁻¹. -1 The reaction temperature of catalyst II is 240-380℃, and the volume hourly space velocity is 0.2-3h. -1 ;

[0046] Preferably, the hydrogen partial pressure is 5-20 MPa, and the hydrogen-to-oil volume ratio is 300-1800; wherein the reaction temperature of catalyst I is 280-360℃, and the volume hourly space velocity is 0.3-2 h⁻¹. -1 The reaction temperature of catalyst II is 260-340℃, and the volume hourly space velocity is 0.3-2h. -1 .

[0047] The second aspect of this disclosure provides a system for the hydrogenation regeneration of waste lubricating oil using the method provided in the first aspect of this disclosure. The system includes: a slurry bed, a fractionation tower, and a high-pressure fixed-bed hydrogenation unit.

[0048] The product outlet of the slurry bed is fluidly connected to the inlet of the fractionation tower, the catalyst-containing tail oil outlet of the fractionation tower is fluidly connected to or vented from the inlet of the slurry bed, and the distillate oil outlet of the fractionation tower is fluidly connected to the inlet of the high-pressure fixed-bed hydrogenation unit.

[0049] Optionally, along the flow direction of the material to be processed, the high-pressure fixed-bed hydrogenation device includes a hydrogenation protection reaction zone and a hydrogenation treatment reaction zone.

[0050] The advantages of the present invention through the above technical solution are as follows:

[0051] (1) This disclosure employs a slurry bed for hydrogenation pretreatment of the entire fraction of waste lubricating oil, which can effectively remove metal and non-metal heteroatoms from the waste oil and saturate some polycyclic aromatic hydrocarbons, reducing the severity of subsequent processing. At the same time, during the slurry bed hydrogenation pretreatment process, more than 50% by weight of the fraction with a boiling point greater than 520°C in the entire fraction of waste lubricating oil can be converted into lubricating oil base oil fraction, and the conversion rate of the fraction with a boiling range of 280-520°C is not higher than 10%, resulting in a high yield of lubricating oil base oil fraction obtained from the regeneration process.

[0052] (2) The oil-soluble catalyst used in the hydropretreatment of this disclosure can be more uniformly dispersed in the waste lubricating oil to ensure sufficient contact for reaction, thereby improving the reaction effect and liquid phase product yield of the catalytic hydropretreatment. The catalyst-containing tail oil is recycled back to the slurry bed, which improves the utilization rate of the catalyst.

[0053] (3) This disclosure enables the deep refining and regeneration of waste lubricating oil by high-pressure hydrogenation of distillate oil, which is beneficial for obtaining high-quality base oil products of various grades through subsequent vacuum distillation.

[0054] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0055] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0056] Figure 1 This is a flowchart illustrating a specific embodiment of the waste lubricating oil hydrogenation regeneration method disclosed herein. Detailed Implementation

[0057] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0058] The first aspect of this disclosure provides a method for hydroregeneration of waste lubricating oil, the method comprising:

[0059] S1. The waste lubricating oil is contacted with the oil-soluble catalyst in a slurry bed for hydrogenation pretreatment to obtain a hydrogenated mixture;

[0060] S2. The hydrogenated mixture is fractionated to obtain gas, distillate oil and catalyst-containing tail oil;

[0061] S3. Introduce a portion of the catalyst-containing tail oil into the slurry bed; discard the remaining portion of the catalyst-containing tail oil.

[0062] In a high-pressure fixed-bed hydrogenation unit, the distillate oil is brought into contact with a hydrogenation catalyst to carry out a high-pressure hydrogenation reaction.

[0063] This disclosed method employs a slurry bed for hydrogenation pretreatment of the entire fraction of waste lubricating oil, effectively removing metal and non-metal heteroatoms and saturating some polycyclic aromatic hydrocarbons, thus reducing the severity of subsequent processing. Simultaneously, the oil-soluble catalyst used in the hydrogenation pretreatment is more uniformly dispersed in the waste lubricating oil to ensure sufficient contact for reaction, thereby improving the reaction efficiency of the catalytic hydrogenation pyrolysis reaction and the yield of liquid-phase products. Furthermore, the catalyst-containing tail oil is recycled back into the slurry bed, improving catalyst utilization. Deep refining and regeneration of waste lubricating oil through high-pressure hydrogenation of the distillate oil facilitates the subsequent production of various grades of high-quality base oil products via vacuum distillation.

[0064] In one specific embodiment of this disclosure, the conditions for the hydrogen pretreatment in step S1 include: a reaction temperature of 300-480℃; a reaction pressure of 2-25 MPa; and a liquid hourly space velocity of 0.2-4 h⁻¹. -1 The volume ratio of hydrogen to the waste lubricating oil (i.e., the hydrogen-to-oil volume ratio) is 100-3000 Nm³. 3 / m 3 Preferably, the reaction temperature is 350-450℃; the reaction pressure is 3-20MPa; and the liquid hourly space velocity is 0.25-3h. -1 The volume ratio of hydrogen to the waste lubricating oil is 200-3000 Nm³. 3 / m 3 .

[0065] In one specific embodiment of this disclosure, in step S1, the oil-soluble catalyst comprises a catalyst main agent and an auxiliary agent; the molar ratio of the catalyst main agent (calculated as a metal element) to the auxiliary agent (calculated as a sulfur element) in the oil-soluble catalyst can vary within a wide range, for example, it can be 1:(0.5-4), preferably 1:(0.5-5). In this disclosure, the catalyst main agent comprises a metal central atom or central ion, and an organic ligand coordinated with the metal central atom or central ion; the general formula of the catalyst main agent is: MO a [R(COOH b ) x ] c Where M represents a metal, R(COOH) b ) xThe organic ligand represents the organic ligand, which includes a carboxyl group and a carboxylic acid group. R represents the hydrocarbon group in the organic ligand. x represents the molar ratio of the total number of the carboxyl group and the carboxylic acid group to the hydrocarbon group R. a represents the molar ratio of the non-coordinate bonded oxygen atom connected to the metal M to the metal M. b represents the molar ratio of the carboxylic acid group to the total number of the carboxyl group and the carboxylic acid group. c represents the molar ratio of the organic ligand to the metal M. The metal is a Group B and / or Group VIII metal with hydrogenation properties; x is 1, 2, or 3, preferably 1 or 2; a is a positive number from 0 to 5, preferably a positive number from 1 to 3; b is a positive number from 0.01 to 0.99, preferably a positive number from 0.1 to 0.5; c is a positive number from 0.5 to 10, preferably a positive number from 1 to 5. In this embodiment, the hydrogenation catalyst main agent has high hydrogenation activity. When used for oil hydrogenation, the coordinating groups of the organic ligands in the hydrogenation catalyst main agent form coordination bonds with the metal central atom or central ion through oxygen atoms. It can be efficiently dispersed in the oil phase and has high hydrogenation activity during the reaction process. It can obtain a high feedstock cracking rate and a heteroatom removal rate, and can maintain a low condensation rate, ultimately achieving the lightening and upgrading of oil feedstock.

[0066] In one specific embodiment of this disclosure, in step S1, based on the dry weight of the catalyst main agent, the metal content in the catalyst main agent is 2-40% by weight, preferably 2-35%, preferably 8-30%, and more preferably 10-20%; the metal is one or more of Ti, V, Cr, Mo, W, Fe, Co, Ru, Ni, Cu, and Zn, preferably one or more of V, Mo, W, Fe, Co, Ni, Cu, and Zn, and more preferably one or more of Mo, W, Ni, Co, and Fe; R is a C3-C19 hydrocarbon group, preferably a C5-C11 normal or isoalkyl group, a C5-C12 cycloalkyl group, or a C6-C12 aryl group.

[0067] In this disclosure, "C3-C19 hydrocarbon group" refers to a hydrocarbon group having 3-19 carbon atoms. The hydrocarbon group can be a saturated or unsaturated straight-chain, branched, or carbocyclic hydrocarbon group, including but not limited to C3-C19 n-alkyl, C3-C19 isoalkyl, C5-C19 cycloalkyl, and C6-C19 aryl. "C5-C11 n-alkyl" refers to a straight-chain alkyl group having 5-11 carbon atoms, such as n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, and n-undecyl. "C5-C11 isoalkyl" refers to a branched alkyl group having 5-11 carbon atoms, such as isopentyl, isohexyl, isoheptyl, isooctyl, isononyl, isodecyl, and isoundecyl. "C5-C12 cycloalkyl" refers to a saturated hydrocarbon group containing a saturated carbon ring with 5-12 carbon atoms, such as cyclopentyl, cyclohexyl, methylcyclohexyl, decahydronaphthyl, methyldecahydronaphthyl, ethyldecahydronaphthyl, etc. "C6-C12 aryl" refers to a group containing an aromatic ring with 6-12 carbon atoms, such as phenyl, naphthyl, anthraceneyl, p-tolyl, benzyl, methylnaphthyl, etc.

[0068] According to this disclosure, the C3-C19 hydrocarbon group, C5-C11 normal alkyl group, C5-C11 isoalkyl group, C5-C12 cycloalkyl group and C6-C12 aryl group may be optionally substituted, for example, they may be unsubstituted, or they may be substituted by one or more groups selected from halogen, nitro, sulfonic acid group and the like.

[0069] In one specific embodiment of this disclosure, the infrared spectrum of the catalyst main agent is at least in the range of 1350-1450 cm⁻¹. -1 and 1500-1610cm -1 It has a characteristic peak at the location.

[0070] According to this disclosure, the catalyst main agent can be highly dispersed in the oil phase, such as oil-soluble molybdenum catalyst, oil-soluble molybdenum-cobalt catalyst, oil-soluble molybdenum-nickel catalyst, oil-soluble iron-molybdenum catalyst, oil-soluble iron-zinc catalyst, etc. In a specific embodiment of this disclosure, the catalyst main agent can be an oil-soluble catalyst such as iron naphthenate or iron carboxylate.

[0071] According to this disclosure, the oil-soluble catalyst includes an additive; the additive includes a sulfur-containing substance, which may include, but is not limited to, one or more of carbon disulfide, sulfur, dimethyl disulfide (DMDS) and di-tert-butyl polysulfide.

[0072] In one specific embodiment of this disclosure, in step S1, the amount of the oil-soluble catalyst, calculated as metal element, relative to 1g of the waste lubricating oil is 20-10000μg, preferably 50-5000μg, and more preferably 100-3000μg.

[0073] In one specific embodiment of this disclosure, the fractionation conditions in step S2 include: a pressure of -90 kPa to -99 kPa and a bottom temperature of 320-370°C; the distillation range of the fractional oil is 280-540°C, preferably 300-520°C; in this disclosure, the fractional oil can be a light lubricating oil base stock, for example, a 150N base oil fraction. The distillation range of the catalyst-containing tail oil fraction is above 500°C, preferably above 520°C. In this embodiment, the total metal content of the fractional oil is not greater than 30 μg / g, and the content of n-heptane insoluble matter is not greater than 300 μg / g.

[0074] According to this disclosure, in step S3, the proportion of the catalyst-containing tail oil introduced into the slurry bed to the total amount of catalyst-containing tail oil can vary within a wide range. In one specific embodiment of this disclosure, in step S3, the amount of catalyst-containing tail oil introduced into the slurry bed accounts for 90-100% by weight of the total amount of catalyst-containing tail oil; the distillation range of the catalyst-containing tail oil is not less than 500°C.

[0075] In one specific embodiment of this disclosure, in step S3, along the flow direction of the distillate oil, the hydrogenation catalyst includes a hydrogenation protection catalyst and a hydrogenation treatment catalyst; based on the total volume of the hydrogenation catalyst and by volume, the amount of the hydrogenation protection catalyst is 10-50%, and the amount of the hydrogenation treatment catalyst is 50-90%.

[0076] In one specific embodiment of this disclosure, in step S3, along the flow direction of the distillate oil, the hydroprotection catalyst sequentially includes catalyst A, catalyst B and catalyst C; based on the total volume of the hydroprotection catalyst, the content of catalyst A is 5-20%, the content of catalyst B is 10-50%, and the content of catalyst C is 30-85%.

[0077] The catalyst A contains a first hydrogenation active metal and a first support; the first hydrogenation active metal includes a Group VB metal and a Group VIB metal, and the first support is selected from alumina and / or silicon oxide; based on the total weight of the catalyst A and calculated as oxides, the content of the Group VB metal is less than 12% by weight, preferably 1-8% by weight, and the content of the Group VIB metal is 0.2-12% by weight, preferably 5-10% by weight; the first support contains phosphorus and halogens, based on the total weight of the first support, the phosphorus content calculated as P2O5 is 0.1-8.0% by weight, preferably 0.1-5.0% by weight, and the halogen content calculated as an element is 0.1-6% by weight, preferably 0.5-2.5% by weight;

[0078] The catalyst B contains a second hydrogenation active metal and a second support; the second hydrogenation active metal includes a Group VIB metal and optionally a Group VIII metal, and the second support is selected from alumina and / or silica; based on the total weight of the catalyst B and calculated as oxides, the content of the Group VIB metal is greater than 0 and less than 4% by weight, preferably 1.5-4% by weight, and the content of the Group VIII metal is 0-0.8% by weight, preferably 0-0.6% by weight; the second support contains phosphorus and halogens, based on the total weight of the second support, the phosphorus content calculated as P2O5 is 0.1-8.0% by weight, preferably 0.1-5% by weight, and the halogen content calculated as an element is 0.1-6% by weight, preferably 0.5-2.5% by weight.

[0079] The catalyst C contains a third hydrogenation active metal and a third support; the third hydrogenation active metal includes Group VIII metals and Group VIB metals, and the third support is selected from alumina and / or silica; based on the total weight of the catalyst C and calculated as oxides, the content of the Group VIB metal is 0.2-10% by weight, preferably 4-8% by weight, and the content of the Group VIII metal is less than 5% by weight, preferably 0.2-4% by weight; the third support contains phosphorus, and based on the total weight of the third support and calculated as P2O5, the phosphorus content is 0.1-8.0% by weight, preferably 0.1-5% by weight.

[0080] In one specific embodiment of this disclosure, the volume ratio of the catalyst A, the catalyst B and the catalyst C is 1:(1-10):(1.5-17), preferably 1:(2-5):(3-15).

[0081] In one specific embodiment of this disclosure, along the flow direction of the distillate oil, the hydrotreating catalyst sequentially comprises catalyst I and catalyst II; by volume and based on the total volume of the hydrotreating catalyst;

[0082] The catalyst I comprises a hydrogenation catalyst Ia, which contains a first promoter, a fourth hydrogenation active metal component, and a fourth support; the first promoter comprises one or more of fluorine, boron, and phosphorus; the metal element in the fourth hydrogenation active metal component comprises one or more of Co, Mo, Ni, and W; the fourth support is selected from alumina and / or silicon oxide; based on the dry weight of the hydrogenation catalyst Ia, the content of the fourth hydrogenation active metal component, calculated as metal oxide, is 16-45% by weight, preferably 22-32% by weight, and the content of the first promoter is 0.5-10% by weight, preferably 0.8-8% by weight;

[0083] Preferably, the catalyst I further includes a hydrogenation catalyst Ib disposed upstream of the hydrogenation catalyst Ia; the hydrogenation catalyst Ib contains a fifth hydrogenation active metal component and a fifth support, and the content of the fifth hydrogenation active metal component (based on the dry weight of the hydrogenation catalyst Ib) is 3-8% by weight; the fifth hydrogenation active metal component is selected from one or more of Co, Mo, Ni and W; the fifth support is selected from alumina and / or silicon oxide;

[0084] More preferably, the weight content of the fifth hydrogenation active metal component of the hydrogenation catalyst Ib is 10-30% of the weight content of the fourth hydrogenation active metal component of the hydrogenation catalyst Ia, preferably 12-25%; preferably, the volume ratio of the hydrogenation catalyst Ia to the hydrogenation catalyst Ib is (10-50):10.

[0085] The second hydrogenation catalyst further includes a hydrogenation catalyst II disposed downstream of the hydrogenation catalyst I; the hydrogenation catalyst II contains a second promoter, a sixth hydrogenation active metal component, and a sixth support. The second promoter includes boron and / or phosphorus. Based on the dry weight of the hydrogenation catalyst II, the content of the sixth hydrogenation active metal component, calculated as metal oxide, is 16-52% by weight, preferably 22-46% by weight. The sixth hydrogenation active metal component is selected from one or more of Co, Mo, Ni, and W. The sixth support is selected from alumina. The catalyst II is a fluorine-free hydrogenation catalyst, and the content of the second promoter is 0-10% by weight, preferably 2-8% by weight. The content of the sixth hydrogenation active metal component of the hydrogenation catalyst II is greater than or equal to the total content of the fourth and fifth hydrogenation active metal components of the hydrogenation catalyst I.

[0086] Preferably, the volume ratio of the hydrogenation catalyst I to the hydrogenation catalyst II is (30:70)-(60:40).

[0087] In one specific embodiment of this disclosure, in step S3, the conditions for the high-pressure hydrogenation reaction in which the distillate oil contacts the hydrotreating protective catalyst include: a hydrogen partial pressure of 3-20 MPa, a hydrogen-to-oil volume ratio of 200-3000, a reaction temperature of 260-380°C, and a volume hourly space velocity of 0.2-5 h⁻¹. -1 Preferably, the hydrogen partial pressure is 5-12 MPa, the hydrogen-to-oil volume ratio is 300-1800, the reaction temperature is 280-360℃, and the volume hourly space velocity is 0.3-3 h⁻¹. -1 .

[0088] The method disclosed herein employs a high-performance hydrogen protection catalyst and a hydrogenation treatment catalyst, and uses a novel catalyst gradation scheme, which can prevent the rapid rise in pressure drop of the high-pressure fixed-bed hydrogenation reactor, extend the operating cycle of the unit, and improve product quality.

[0089] In one specific embodiment of this disclosure, in step S3, the conditions for the high-pressure hydrogenation reaction of the distillate oil in contact with the hydrotreating catalyst include: a hydrogen partial pressure of 3-25 MPa and a hydrogen-to-oil volume ratio of 200-3000; wherein the reaction temperature of catalyst I is 260-420°C and the volume hourly space velocity is 0.2-3 h⁻¹. -1 The reaction temperature of catalyst II is 240-380℃, and the volume hourly space velocity is 0.2-3h. -1 Preferably, the hydrogen partial pressure is 5-20 MPa, and the hydrogen-to-oil volume ratio is 300-1800; wherein the reaction temperature of catalyst I is 280-360℃, and the volume hourly space velocity is 0.3-2 h⁻¹. -1 The reaction temperature of catalyst II is 260-340℃, and the volume hourly space velocity is 0.3-2h. -1 .

[0090] In this disclosure, the reaction pressure of the high-pressure hydrogenation reaction in the presence of the hydrotreating catalyst is higher than that of the high-pressure hydrogenation reaction in the presence of the hydroprotecting catalyst.

[0091] The second aspect of this disclosure provides a system for the hydrogenation regeneration of waste lubricating oil using the method provided in the first aspect of this disclosure. The system includes: a slurry bed, a fractionation tower, and a high-pressure fixed-bed hydrogenation unit; the product outlet of the slurry bed is fluidly connected to the inlet of the fractionation tower, the catalyst-containing tail oil outlet of the fractionation tower is fluidly connected to or vented from the inlet of the slurry bed, and the distillate oil outlet of the fractionation tower is fluidly connected to the inlet of the high-pressure fixed-bed hydrogenation unit.

[0092] In one specific embodiment of this disclosure, the high-pressure fixed-bed hydrogenation device includes a hydrogenation protection reaction zone and a hydrogenation treatment reaction zone along the flow direction of the material to be treated.

[0093] The present invention will be further described in detail below through examples.

[0094] The properties of the waste lubricating oil regenerated in the following examples and comparative examples are shown in Table 1. Unless otherwise specified, all reagents used were commercially available.

[0095] Table 1 Properties of waste lubricating oil

[0096]

[0097]

[0098] The preparation methods and reaction raw materials of the oil-soluble catalyst main agent used in Examples 1-9 are shown in Table 2. The specific method is as follows: Weigh the corresponding weight of the compound as shown in Table 2, place it in a three-necked flask, and then carry out the reaction under the conditions shown in Table 2. Separate the gas generated during the reaction. After the reaction is completed, the metal compound in the flask is completely dissolved. Pour out the liquid reaction product in the flask and place it in a separatory funnel for oil-water separation. Let it stand for 2 hours, and separate the liquid to obtain the upper oil phase product, which is the catalyst main agent of the oil-soluble catalyst.

[0099] Table 2

[0100]

[0101]

[0102] Example 1

[0103] S1. Waste lubricating oil is contacted with an oil-soluble catalyst in a slurry bed for hydrogenation pretreatment to obtain a hydrogenation mixture; wherein the oil-soluble catalyst contains a main agent and an auxiliary agent.

[0104] S2. Fractionate the hydrogenated mixture to obtain gas, distillate oil, and catalyst-containing tail oil;

[0105] S3. Introduce a portion of the catalyst-containing tail oil into the slurry bed; discard the remaining portion of the catalyst-containing tail oil.

[0106] In a high-pressure fixed-bed hydrogenation unit, distillate oil is brought into contact with a catalyst to carry out a high-pressure hydrogenation reaction.

[0107] The reaction conditions, product results, and product property analysis results for the above steps are shown in Table 5.

[0108] Along the flow direction of the distillate oil, the hydroprotection catalyst includes catalyst A, catalyst B and catalyst C arranged in sequence, and the composition of the catalyst is shown in Table 3.

[0109] Catalyst A contains 8.0 wt% MoO3, 1.6 wt% V2O5, and the balance being a support. Based on the dry weight of the support, the phosphorus content (calculated as P2O5) is 4.9 wt%, and the halogen fluorine content (based on elemental composition) is 1.0 wt%.

[0110] The alumina was prepared as follows: 2 L of aluminum sulfate solution with an Al2O3 concentration of 50 g / L was prepared, and 5 mL of concentrated phosphoric acid (85% by weight, the same below) and 9.5 g of boric acid were added to obtain an aluminum sulfate solution containing phosphorus and boron. The above aluminum sulfate solution and an 8% ammonia solution were added in parallel flow to a 5 L reaction vessel to allow precipitation. The mixture was then filtered (XRD characterization showed that the hydrated alumina precipitate had an amorphous structure). The reaction temperature was 40 °C, and the flow rate of the ammonia solution was controlled to maintain the pH of the reaction system at 5.5. In a 5-liter reaction vessel, filter cake, deionized water, and ammonia were mixed and slurried. The amount of ammonia was adjusted to a pH of 8.0. The slurry was aged at 65°C for 60 minutes and then filtered. The filter cake was washed twice with deionized water and dried at 120°C for 24 hours to obtain hydrated alumina P1. P1 was calcined at 600°C for 4 hours to obtain alumina Al. XRD characterization showed that P1 had a boehmite-like structure, and Al had a γ-alumina structure. 1000g of hydrated alumina P1 was weighed and added to 1440ml of an aqueous solution containing 10ml of nitric acid (from Tianjin Chemical Reagent Factory No. 3) and 9.8g of ammonium fluoride. The solution was extruded into butterfly-shaped strips with an outer diameter of φ1.4mm on a twin-screw extruder. The wet strip was dried at 120°C for 4 hours to obtain a molded article. The molded article was calcined at 600°C for 3 hours to obtain support Z1. It was impregnated with 220 mL of a mixed solution of ammonium heptamolybdate and ammonium vanadate containing 80 g / L MoO3 and 16 g / L V2O5 for 1 hour, dried at 120°C for 4 hours, and calcined at 400°C for 3 hours to obtain catalyst A.

[0111] Catalyst B contains 2.0 wt% WO3, 0.2 wt% CoO, and the balance is a support. Based on the dry weight of the support, the phosphorus content (calculated as P2O5) is 3.5 wt%, and the halogen fluorine content (based on elemental composition) is 1.0 wt%.

[0112] The alumina was prepared as follows: 2 L of aluminum sulfate solution with an Al2O3 concentration of 90 g / L was prepared, and 6 mL of concentrated phosphoric acid and 51 g of magnesium sulfate heptahydrate were added to obtain an aluminum sulfate solution containing phosphorus and magnesium. The above-mentioned aluminum sulfate solution containing phosphorus and magnesium and an 8% ammonia solution were added in parallel flow to a 5 L reaction vessel to allow precipitation. The precipitate was then filtered (XRD characterization showed that the hydrated alumina precipitate had an amorphous structure). The reaction temperature was 45 °C, and the flow rate of the ammonia solution was controlled to maintain the pH of the reaction system at 6.0. In a 5-liter reaction vessel, filter cake, deionized water, and ammonium bicarbonate were mixed and slurried. The amount of ammonia added was adjusted to a pH of 9.2. The slurry was aged at 40°C for 240 minutes and then filtered. The filter cake was washed twice with deionized water and dried at 120°C for 14 hours to obtain hydrated alumina P2. XRD characterization showed that P2 had a pseudoboehmite structure. P2 was calcined at 600°C for 4 hours to obtain alumina A2, which, according to XRD, had a γ-alumina structure. 1000g of the prepared hydrated alumina P2 was weighed and added to 1440ml of a mixture containing 10ml of nitric acid (from Tianjin Chemical Reagent Factory No. 3) and 9.8g of ammonium fluoride. The mixture was extruded into a butterfly-shaped strip with an outer diameter of φ1.4mm on a twin-screw extruder. The wet strip was dried at 120°C for 4 hours to obtain a molded product. This molded product was calcined at 600°C for 3 hours to obtain carrier Z2.

[0113] Take 200 g of support Z2, impregnate it for 1 hour with 220 mL of a mixed solution of ammonium tungstate and ammonium vanadate containing 19 g / L WO3 and 2 g / L CoO, dry it at 120 °C for 4 hours, and calcine it at 400 °C for 3 hours to obtain hydrogenation catalyst B.

[0114] Catalyst C contains 6.0 wt% WO3, 1.0 wt% CoO, and the balance being a support. Based on the total weight of the support, the phosphorus content, calculated as P2O5, is 2.5 wt%.

[0115] The solution was prepared as follows: 2 L of aluminum nitrate solution with an Al2O3 concentration of 50 g / L was prepared, and 5 mL of phosphoric acid was added to obtain an aluminum nitrate solution containing phosphorus. The above aluminum nitrate solution and a sodium aluminate solution containing 200 g / L alumina and a caustic coefficient of 1.58 were added concurrently to a 5 L reaction vessel to induce precipitation. The precipitate was then filtered (XRD characterization showed the hydrated alumina precipitate to be amorphous). The reaction temperature was 60 °C, and the flow rate of the sodium aluminate solution was controlled to maintain the pH of the reaction system at 6.0. In a 5-liter reaction vessel, filter cake, deionized water, and ammonium bicarbonate (chemically pure, product of Beijing Yili Fine Chemicals Co., Ltd.) were mixed and slurried. The amount of ammonium bicarbonate was adjusted to make the pH of the slurry 8.0. After aging at 55℃ for 4 hours, the slurry was filtered. The filter cake was washed twice with deionized water and dried at 120℃ for 24 hours to obtain hydrated alumina P6. XRD characterization showed that P6 had a pseudoboehmite structure. P6 was calcined at 600℃ for 4 hours to obtain alumina A6. 1000g of P6 was weighed and added to 1440ml of an aqueous solution containing 10ml of nitric acid (product of Tianjin Chemical Reagent Factory No. 3). The mixture was extruded into a butterfly-shaped strip with an outer diameter of φ1.4mm on a twin-screw extruder. The wet strip was dried at 120℃ for 4 hours to obtain a molded product. The molded product was calcined at 600℃ for 3 hours to obtain carrier Z6.

[0116] Take 200 g of support Z6, impregnate it with 220 mL of a mixed solution of ammonium tungstate and ammonium vanadate containing 59 g / L WO3 and 10 g / L CoO for 1 hour, dry it at 120 °C for 4 hours, and calcine it at 400 °C for 3 hours to obtain catalyst C.

[0117] Table 3 Composition of catalysts A, B, and C

[0118]

[0119] Along the flow direction of the distillate oil, the hydrotreating catalysts sequentially include hydrotreating catalyst Ib, hydrotreating catalyst Ia, and catalyst II. The composition of the catalysts is shown in Table 4.

[0120] The hydrogenation catalyst Ia contains 5 wt% NiO, 5 wt% MoO3, 20 wt% WO3, 5 wt% P2O5 and 65 wt% support.

[0121] The solution was prepared as follows: 3127g of Al2(SO4)3·18H2O and 338g of 98% sulfuric acid were dissolved in 4968g of deionized water to prepare solution I (pH 0.70, Al2O3 content 95g / L). 2070g of water glass (industrial grade, modulus: 3.26, SiO2 279.8g / L, Na2O 87.3g / L, iron oxide content 0.085% by weight, the same below) was diluted with water, and then 1.75g ​​of ferrous sulfate was added to prepare solution II (containing SiO2 80g / L, pH 12.61). Solution II was added to solution I under vigorous stirring to prepare a transparent silicon-aluminum mixed solution III, with a pH of 2.2 and a SiO2 / Al2O3 mass ratio of 1.0. Dilute ammonia (containing 5% NH3 by weight) and silicon-aluminum mixed solution III were mixed at a stirring speed of 3000 RPM. The ammonia was added at a rate that adjusted the pH of the mixture to within the range of 8.0 ± 0.3.

[0122] After the ammonia water was added, the resulting product was stirred at 55-60℃ for 10 hours, filtered, and the resulting filter cake was mixed with hot deionized water, slurried, and filtered. This step was repeated 4 times, and the filter cake was dried at 120℃ overnight. The precursor SAS-2 of the silicon-aluminum composite material carrier was obtained. Based on the weight of the added ferrous sulfate and the obtained precursor SAS-2, the iron content in the precursor of the silicon-aluminum composite material carrier, calculated as Fe2O3, was 0.3% by weight.

[0123] The precursor SAS-2 of the silicon-aluminum composite material carrier was extruded into cylindrical strips with a diameter of 1.5 mm. The cylindrical strips were then dried at 120°C for 5 hours and calcined at 600°C for 2 hours to obtain the catalyst carrier strips.

[0124] Concentrated phosphoric acid (85 wt%, analytical grade, Beijing Chemical Plant, hereinafter the same) and deionized water were heated to 75°C and then mixed with basic nickel carbonate (industrial grade, from Changling Catalyst Plant, hereinafter the same) and molybdenum trioxide (industrial grade, from Changling Catalyst Plant, hereinafter the same). The mixture was heated and stirred until dissolved, and the solution became clear and transparent. After cooling to room temperature, solution I was obtained. Ammonium metatungstate (industrial grade, Sichuan Zigong Hard Alloy Plant, hereinafter the same) and nickel nitrate (analytical grade, Beijing Shuanghuan Chemical Reagent Plant, hereinafter the same) were added to deionized water and stirred until dissolved, resulting in solution II. Solution I and solution II were mixed at room temperature and adjusted to 160 mL with deionized water to obtain solution III (the amounts of NiO, WO3, MoO3 and P2O5 were prepared according to 5 wt%, 20 wt%, 5 wt%, and 5 wt%, respectively). 200 g of the above support strip was impregnated with solution III for 2 hours, then the support strip was removed and dried at 120°C for 4 hours, and then calcined at 500°C with air for 1 hour to obtain hydrogenation catalyst Ia.

[0125] The hydrogenation catalyst Ib uses commercially available RG-1 catalyst, produced by Changling Catalyst Factory, containing 1.0 wt% NiO, 5.5 wt% MoO3, and the remainder alumina support.

[0126] Catalyst II contains 6.7 wt% NiO, 32.0 wt% WO3, 6.2 wt% MoO3, 5.9 wt% P2O5 and the balance support.

[0127] It was prepared by the following method: 200.0 g of industrial alumina support was weighed and impregnated with 178 mL of an aqueous solution containing 31.2 g of ammonium paramolybdate for 3 hours, dried at 120 °C for 4 hours, and then impregnated with 168 mL of an aqueous solution containing 108.2 g of nickel nitrate, 151.3 g of ammonium metatungstate and 48.7 g of phosphoric acid for 3 hours, dried at 120 °C for 4 hours and calcined at 450 °C for 4 hours to obtain hydrogenation catalyst II.

[0128] Table 4 Composition of hydrogenation catalysts Ia, II, and Ib

[0129]

[0130] Examples 2-9

[0131] Waste lubricating oil was treated using the same method as in Example 1, except that the reaction conditions were different, as shown in Table 5.

[0132] Comparative Example 1

[0133] Waste lubricating oil was processed using a conventional vacuum fractionation-hydrorefining process. The properties of the base oil intermediates obtained from vacuum fractionation are shown in Table 6. The yield of the base oil intermediates after vacuum fractionation was 82%. After hydrorefining, the yield of the base oil was approximately 95%. Specific process parameters are shown in Table 7.

[0134] Table 5

[0135]

[0136]

[0137] In the table, the amount of oil-soluble catalyst (μg / g) refers to the amount of oil-soluble catalyst, calculated as metal element, relative to 1g of the waste lubricating oil.

[0138] Catalyst I includes hydrogenation catalyst Ia and hydrogenation catalyst Ib. The reaction conditions for hydrogenation catalyst Ia and hydrogenation catalyst Ib are the same, as shown in the table below.

[0139] Table 6

[0140]

[0141]

[0142] Table 7

[0143]

[0144]

[0145] As can be seen from the above, the method disclosed herein can effectively remove metal and non-metal heteroatoms from waste lubricating oil, reduce the severity of subsequent processing, and prepare high-quality lubricating oil base oil.

[0146] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0147] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0148] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for hydrogenating and regenerating waste lubricating oil, the method comprising: S1. The waste lubricating oil is contacted with the oil-soluble catalyst in a slurry bed for hydrogenation pretreatment to obtain a hydrogenated mixture; S2. The hydrogenated mixture is fractionated to obtain gas, distillate oil and catalyst-containing tail oil; S3. Introduce a portion of the catalyst-containing tail oil into the slurry bed; The remaining portion of the catalyst-containing tail oil was thrown off; In a high-pressure fixed-bed hydrogenation unit, the distillate oil is brought into contact with a hydrogenation catalyst to carry out a high-pressure hydrogenation reaction.

2. The method according to claim 1, wherein, In step S1, the conditions for the hydrogen pretreatment include: a reaction temperature of 300-480℃; a reaction pressure of 2-25 MPa; and a liquid hourly space velocity of 0.2-4 h⁻¹. -1 The volume ratio of hydrogen to the waste lubricating oil is 100-3000 Nm³. 3 / m 3 .

3. The method according to claim 1, wherein, In step S1, the oil-soluble catalyst includes a catalyst main agent and an auxiliary agent; the molar ratio of the catalyst main agent (calculated as metal element) to the auxiliary agent (calculated as sulfur element) in the oil-soluble catalyst is 1:(0.5-5), preferably 1:(0.5-4); The additive includes sulfur-containing substances; preferably, the sulfur-containing substances include one or more of carbon disulfide, sulfur, dimethyl disulfide and di-tert-butyl polysulfide. The catalyst host comprises a metal central atom or central ion, and an organic ligand coordinated with the metal central atom or central ion; the general formula of the catalyst host is: MO a [R(COOH b ) x ] c , Where M represents a metal, R(COOH) b ) x The organic ligand represents the organic ligand comprising a carboxyl group and a carboxylic acid group, R represents the hydrocarbon group in the organic ligand, x represents the molar ratio of the total number of the carboxyl group and the carboxylic acid group to the hydrocarbon group R, a represents the molar ratio of the noncoordinate bonded oxygen atom connected to the metal M to the metal M, b represents the molar ratio of the carboxylic acid group to the total number of the carboxyl group and the carboxylic acid group, and c represents the molar ratio of the organic ligand to the metal M, wherein: The metal is a Group B and / or Group VIII metal with hydrogenation properties; x is 1, 2 or 3, preferably 1 or 2; a is a positive number from 0 to 5, preferably a positive number from 1 to 3; b is a positive number between 0.01 and 0.99, preferably a positive number between 0.1 and 0.5; c is a positive number between 0.5 and 10, preferably a positive number between 1 and 5.

4. The method according to claim 3, wherein, In step S1, based on the dry weight of the catalyst main agent, the metal content in the catalyst main agent is 2-40% by weight, preferably 2-35%, preferably 8-30%, and more preferably 10-20%. The metal is one or more of Ti, V, Cr, Mo, W, Fe, Co, Ru, Ni, Cu and Zn, preferably one or more of V, Mo, W, Fe, Co, Ni, Cu and Zn, and more preferably one or more of Mo, W, Ni, Co and Fe; R is a C3-C19 hydrocarbon group, preferably a C5-C11 normal or isomeric alkyl group, a C5-C12 cycloalkyl group, or a C6-C12 aryl group.

5. The method according to claim 1, wherein, In step S1, the amount of the oil-soluble catalyst, calculated as metal element, is 20-10000 μg relative to 1g of the waste lubricating oil, preferably 50-5000 μg, and more preferably 100-3000 μg.

6. The method according to claim 1, wherein, In step S2, the fractionation conditions include: a pressure of -90 kPa to -99 kPa and a bottom temperature of 320-370 °C. The distillation range of the distillate oil is 280-540℃, preferably 300-520℃; The distillation range of the catalyst-containing tail oil is above 500°C, preferably above 520°C.

7. The method according to claim 1, wherein, In step S3, the amount of catalyst-containing tail oil introduced into the slurry bed accounts for 90-100% by weight of the total amount of catalyst-containing tail oil.

8. The method according to claim 1, wherein, In step S3, along the flow direction of the distillate oil, the hydrogenation catalyst includes a hydrogenation protection catalyst and a hydrogenation treatment catalyst; Based on the total volume of the hydrogenation catalyst and by volume, the amount of the hydrogenation protection catalyst is 10-50%, and the amount of the hydrogenation treatment catalyst is 50-90%.

9. The method according to claim 8, wherein, In step S3, along the flow direction of the distillate oil, the hydroprotection catalyst sequentially includes catalyst A, catalyst B and catalyst C; Based on the total volume of the hydrogenation protection catalyst, the content of catalyst A is 5-20%, the content of catalyst B is 10-50%, and the content of catalyst C is 30-85%. The catalyst A contains a first hydrogenation active metal and a first support; the first hydrogenation active metal includes Group VB metals and Group VIB metals, and the first support is selected from alumina and / or silicon oxide; based on the total weight of the catalyst A and calculated as oxides, the content of the Group VB metal is less than 12% by weight, and the content of the Group VIB metal is 0.2-12% by weight; the first support contains phosphorus and halogens, based on the total weight of the first support, the phosphorus content is 0.1-8.0% by weight (calculated as P2O5), and the halogen content is 0.1-6% by weight (calculated as an element). The catalyst B contains a second hydrogenation active metal and a second support; the second hydrogenation active metal includes a Group VIB metal and optionally a Group VIII metal, and the second support is selected from alumina and / or silica; based on the total weight of the catalyst B and calculated as oxides, the content of the Group VIB metal is greater than 0 and less than 4% by weight, and the content of the Group VIII metal is 0-0.8% by weight; the second support contains phosphorus and halogens, based on the total weight of the second support, the phosphorus content is 0.1-8.0% by weight (calculated as P2O5), and the halogen content is 0.1-6% by weight (calculated as an element). The catalyst C contains a third hydrogenation active metal and a third support; the third hydrogenation active metal includes Group VIII metals and Group VIB metals, and the third support is selected from alumina and / or silica; based on the total weight of the catalyst C and calculated as oxides, the content of the Group VIB metal is 0.2-10% by weight, and the content of the Group VIII metal is less than 5% by weight; the third support contains phosphorus, and based on the total weight of the third support, the phosphorus content calculated as P2O5 is 0.1-8.0% by weight. Preferably, the volume ratio of catalyst A, catalyst B and catalyst C is 1:(1-10):(1.5-17), more preferably 1:(2-5):(3-15); Along the flow direction of the distillate oil, the hydrotreating catalyst sequentially comprises catalyst I and catalyst II; The catalyst I comprises a hydrogenation catalyst Ia, which contains a fourth promoter, a fourth hydrogenation active metal component, and a fourth support; the first promoter comprises one or more of fluorine, boron, and phosphorus; the first hydrogenation active metal comprises one or more of Co, Mo, Ni, and W; the fourth support is selected from alumina and / or silicon oxide; based on the dry weight of the hydrogenation catalyst Ia, the content of the fourth hydrogenation active metal component, calculated as metal oxide, is 16-45% by weight, and the content of the first promoter is 0.5-10% by weight; Preferably, the catalyst I further includes a hydrogenation catalyst Ib disposed upstream of the hydrogenation catalyst Ia; the hydrogenation catalyst Ib contains a fifth hydrogenation active metal component and a fifth support, and the content of the fifth hydrogenation active metal component, calculated as metal oxide, is 3-8% by weight based on the dry basis weight of the hydrogenation catalyst Ib. The fifth hydrogenation active metal component is selected from one or more of Co, Mo, Ni and W; the fifth support is selected from alumina and / or silicon oxide; More preferably, the weight content of the fifth hydrogenation active metal component of the hydrogenation catalyst Ib is 10-30% of the weight content of the fourth hydrogenation active metal component of the hydrogenation catalyst Ia, preferably 12-25%; preferably, the volume ratio of the hydrogenation catalyst Ia to the hydrogenation catalyst Ib is (10-50):

10. The second hydrogenation catalyst further includes a hydrogenation catalyst II disposed downstream of the hydrogenation catalyst I; the hydrogenation catalyst II contains a second promoter, a sixth hydrogenation active metal component, and a sixth support, the second promoter comprising boron and / or phosphorus, and the content of the sixth hydrogenation active metal component, based on the dry weight of the hydrogenation catalyst II and calculated as metal oxide, is 16-52% by weight; the sixth hydrogenation active metal component is selected from one or more of Co, Mo, Ni, and W; the sixth support is selected from alumina; the catalyst II is a fluorine-free hydrogenation catalyst, and the content of the second promoter is 2-8% by weight; the content of the sixth hydrogenation active metal component of the hydrogenation catalyst II is greater than or equal to the total content of the fourth and fifth hydrogenation active metal components of the hydrogenation catalyst I; Preferably, the volume ratio of the hydrogenation catalyst I to the hydrogenation catalyst II is (30:70)-(60:40).

10. The method according to claim 8, wherein, In step S3, the conditions for the high-pressure hydrogenation reaction between the distillate oil and the hydrotreating protective catalyst include: a hydrogen partial pressure of 3-20 MPa, a hydrogen-to-oil volume ratio of 200-3000, a reaction temperature of 260-380°C, and a volume hourly space velocity of 0.2-5 h⁻¹. -1 ; Preferably, the hydrogen partial pressure is 5-12 MPa, the hydrogen-to-oil volume ratio is 300-1800, the reaction temperature is 280-360℃, and the volume hourly space velocity is 0.3-3 h⁻¹. -1 .

11. The method according to claim 8, wherein, In step S3, the conditions for the high-pressure hydrogenation reaction between the distillate oil and the hydrotreating catalyst include: a hydrogen partial pressure of 3-25 MPa and a hydrogen-to-oil volume ratio of 200-3000; wherein the reaction temperature of catalyst I is 260-420°C and the volume hourly space velocity is 0.2-3 h⁻¹. -1 The reaction temperature of catalyst II is 240-380℃, and the volume hourly space velocity is 0.2-3h. -1 ; Preferably, the hydrogen partial pressure is 5-20 MPa, and the hydrogen-to-oil volume ratio is 300-1800; wherein the reaction temperature of catalyst I is 280-360℃, and the volume hourly space velocity is 0.3-2 h⁻¹. -1 The reaction temperature of catalyst II is 260-340℃, and the volume hourly space velocity is 0.3-2h. -1 .

12. A system for hydrogenating and regenerating waste lubricating oil using any one of claims 1-11, the system comprising: Slurry bed, fractionation tower and high-pressure fixed bed hydrogenation units; The product outlet of the slurry bed is fluidly connected to the inlet of the fractionation tower, the catalyst-containing tail oil outlet of the fractionation tower is fluidly connected to or vented from the inlet of the slurry bed, and the distillate oil outlet of the fractionation tower is fluidly connected to the inlet of the high-pressure fixed-bed hydrogenation unit.

13. The system according to claim 12, wherein, Along the flow direction of the material to be processed, the high-pressure fixed-bed hydrogenation device includes a hydrogenation protection reaction zone and a hydrogenation treatment reaction zone.

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