A method for the pretreatment of used lubricating oil

Abstract

The present disclosure relates to a method for pretreating waste lubricating oil, which comprises: S1, carrying out hydrogenation pretreatment of mixed slurry in a slurry bed to obtain a hydrogenation mixture; wherein the mixed slurry contains waste lubricating oil, hydrogenation pretreatment catalyst and promoter; the hydrogenation pretreatment catalyst comprises oil-soluble catalyst and / or carbon carrier catalyst; the promoter comprises sulfur-containing substances and alkali solution; S2, separating the hydrogenation mixture to obtain gas phase materials, distillate oil and catalyst-containing tail oil. The method has strong adaptability to raw materials, high impurity removal rate and high yield of liquid phase products.

Description

Technical Field

[0001] This application relates to a method for pretreatment of waste lubricating oil. Background Technology

[0002] With the sustained high-speed growth of China's economy, the consumption of lubricating oil products is also increasing year by year. In 2023, my country's apparent consumption of lubricating oil was approximately 7.48 million tons, which will generate approximately 4.7 million tons of waste lubricating oil. Researching and developing methods suitable for the regeneration of waste lubricating oil has significant social and economic benefits and huge market potential. Therefore, in recent years, people have begun to pay attention to the recycling of waste lubricating oil and expect the recycled oil to reach the quality level of new lubricating oil base oil.

[0003] Because lubricating oil products contain a wide variety of additives, such as anti-wear agents, friction modifiers, dispersants, foaming agents, corrosion and rust inhibitors, and viscosity index promoters, these additives often contain metal compounds such as calcium, zinc, copper, barium, magnesium, and lead. Therefore, waste oil also contains various heavy metal compounds from these additives. Currently, the widely used technology involves pre-hydrogenation refining in a reactor containing a protective agent, which can remove most additives and metals. However, during the hydrogenation reaction, these metals easily deposit on the surface of the hydrogenation catalyst, causing rapid catalyst poisoning, leading to catalyst deactivation and shortened service life. They also easily deposit on the outer surface of catalyst particles or accumulate between particles, causing catalyst bed agglomeration and blockage, resulting in a rapid increase in reactor pressure drop, requiring shutdown and catalyst replacement. Furthermore, due to the diverse sources of waste lubricating oil, its impurities and composition fluctuate greatly, placing higher demands on the continuity of the production process and the stability of long-term operation.

[0004] Therefore, proposing a new waste lubricating oil hydrogenation pretreatment process that can be used to process complex and varied waste oil raw materials and eliminate the adverse effects on traditional hydrogenation processes is a technical problem that urgently needs to be solved in this field.

[0005] CN101041789A discloses a method for hydrogenating and regenerating waste lubricating oil. This method includes the following steps: the raw waste lubricating oil is subjected to dehydration, filtration, and adsorption treatment to remove water, mechanical impurities, gums, asphaltenes, and most heavy metal impurities; the adsorbed waste lubricating oil is further purified by pre-hydrogenation in a reactor containing a protective agent to remove impurities; the pre-hydrogenated waste lubricating oil enters the main hydrogenation reactor, where hydrogenation is achieved under the action of a hydrogenation catalyst, saturating the non-ideal components in the raw oil with hydrogen, and the product is fractionated. This method only removes some mechanical impurities through physical methods and hydrogenation protective agents, resulting in limited removal of gums and asphaltenes from the heavy fraction of the waste lubricating oil, and the operating cycle cannot be guaranteed. Furthermore, due to the mixed sources of the waste lubricating oil, hydrogenation alone results in low product quality and is heavily dependent on the quality of the raw materials. Summary of the Invention

[0006] The purpose of this disclosure is to provide a method and system for pretreatment of waste lubricating oil. This method has strong raw material adaptability, high impurity removal rate, and high liquid phase product yield, and can provide high-quality pretreatment raw materials for subsequent fixed bed units.

[0007] To achieve the above objectives, this disclosure provides a method for pretreating waste lubricating oil, the method comprising: S1, subjecting a mixed slurry to hydrotreating in a slurry bed to obtain a hydrogenated mixture; wherein the mixed slurry contains waste lubricating oil, a hydrotreating catalyst, and an accelerator; the hydrotreating catalyst comprises an oil-soluble catalyst and / or a carbon-supported catalyst; the accelerator comprises a sulfur-containing substance and an alkaline solution; the amount of the hydrotreating catalyst, calculated as metal element, relative to 1g of waste lubricating oil is 20-100000μg, and the weight ratio of the accelerator to the amount of the hydrotreating catalyst, calculated as metal element, is (0.4-200):1; S2, separating the hydrogenated mixture to obtain a gaseous material, a distillate oil, and a catalyst-containing tail oil.

[0008] Optionally, in step S1, the weight ratio of the sulfur-containing substance to the alkaline solution is 1:(0.1-300), preferably 1:(0.5-250).

[0009] Optionally, in step S1, the amount of the hydrogen pretreatment catalyst, calculated as metal element, relative to 1g of waste lubricating oil is 50-50000μg, preferably 100-3000μg, and the weight ratio of the promoter to the amount of the hydrogen pretreatment catalyst, calculated as metal element, is (0.6-150):1.

[0010] Optionally, in step S1, the accelerator further contains a calcium-containing inorganic compound; the amount of the calcium-containing inorganic compound is 0.001-0.03g relative to 1g of waste lubricating oil.

[0011] Preferably, the calcium-containing inorganic compound includes one or more of calcium carbonate, calcium oxide, and calcium hydroxide.

[0012] Optionally, in step S1, the sulfur-containing substance is selected from one or more of sublimed sulfur, carbon disulfide, dimethyl sulfide, and sulfur-containing low-element gas;

[0013] The alkaline solution is selected from sodium hydroxide solution and / or potassium hydroxide solution, and the concentration of the alkaline solution is 0.5-20% by weight.

[0014] Optionally, in step S1, the temperature of the mixed slurry is 20-200℃, preferably 40-150℃;

[0015] The conditions for the hydrogen pretreatment include: a reaction temperature of 300-480℃, preferably 350-410℃; a reaction pressure of 2-20 MPa, preferably 4-12 MPa; and a liquid hourly space velocity of 0.2-4 h⁻¹. -1 Preferably 0.25-2h -1 The volume ratio of hydrogen to the waste lubricating oil is 100-3000 Nm³. 3 / m 3 Preferably 200-3000 Nm 3 / m 3 .

[0016] Optionally, the oil-soluble catalyst contains 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 hydrogenation catalyst is: MO a [R(COOH b ) x ] c ,

[0017] 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:

[0018] The metal is a Group B and / or Group VIII metal with hydrogenation properties;

[0019] x is 1, 2 or 3, preferably 1 or 2;

[0020] a is a positive number from 0 to 5, preferably a positive number from 1 to 3;

[0021] b is a positive number between 0.01 and 0.99, preferably a positive number between 0.1 and 0.5;

[0022] c is a positive number between 0.5 and 10, preferably a positive number between 1 and 5.

[0023] Optionally, based on the dry weight of the oil-soluble catalyst, the metal content in the oil-soluble catalyst is 2-40% by weight, preferably 2-35%, more preferably 8-30%, and even more preferably 10-20%.

[0024] 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;

[0025] 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.

[0026] Optionally, the carbon-supported catalyst comprises a carbon-based support and an active metal component; based on the total weight of the carbon-supported catalyst and calculated by metal element, the content of the active metal component is 1-50% by weight, preferably 2-40% by weight;

[0027] The carbon-based carrier comprises carbon-containing materials with a carbon content greater than 80% by weight; the metal elements in the active metal component include one or more of Fe, Co, Mo, W and Ni.

[0028] Optionally, step S1 includes:

[0029] SS1. Hydrogen gas is introduced into a hydrogen preheating furnace for preheating to obtain preheated hydrogen gas;

[0030] SS2, The preheated hydrogen and the mixed slurry are introduced into the raw material preheating furnace for heating, and the resulting preheated material is introduced into the slurry bed for the hydrogen pretreatment; or,

[0031] A portion of the preheated hydrogen gas and the mixed slurry are introduced into a raw material preheating furnace for heating. The resulting preheated material, along with the remaining portion of the preheated hydrogen gas, is then introduced into the slurry bed for the hydrogen pretreatment. Optionally, the preheated hydrogen gas introduced into the raw material preheating furnace accounts for 1-50% by volume of the total preheated hydrogen gas.

[0032] The mixed slurry is introduced into a raw material preheating furnace for heating, and the resulting preheated material and the preheated hydrogen are introduced into the slurry bed for hydrogen pretreatment.

[0033] Optionally, the method further includes step S3: mixing a portion of the catalyst-containing tail oil with the mixed slurry and then introducing it into the slurry bed;

[0034] Preferably, the amount of catalyst-containing tail oil introduced into the slurry bed accounts for 5-40% by weight of the total amount of catalyst-containing tail oil.

[0035] Optionally, step S2 includes:

[0036] SS1. The hydrogenated mixture is introduced into a hot high-pressure separator for the first separation to obtain a gas phase component and a liquid phase component;

[0037] SS2. The gas phase component is introduced into a cold high-pressure separator for a second separation, the gas phase component obtained from the second separation is introduced into a cold low-pressure separator for a third separation, the gas phase component obtained from the third separation is introduced into a hydrogen separator for a fourth separation, and the hydrogen obtained from the fourth separation is introduced into the slurry bed.

[0038] The liquid phase component is introduced into a thermal low-pressure separator for a fifth separation, and the liquid phase component obtained from the fifth separation is subjected to solid-liquid separation.

[0039] The method disclosed herein has the following advantages through the above technical solution:

[0040] (1) The present invention uses slurry bed hydrogenation pretreatment of waste lubricating oil fraction, which can effectively remove metal and non-metal heteroatoms from waste oil and saturate some polycyclic aromatic hydrocarbons, reducing the severity of subsequent processing and improving the operating cycle of subsequent fixed bed units.

[0041] (2) In this disclosure, by using specific amounts of hydrogen pretreatment catalyst and accelerator, the conversion rate of the lubricating oil base oil fraction (280-520℃) in waste lubricating oil can be kept to no more than 15%, which is beneficial to improving the yield of the lubricating oil base oil fraction obtained in the subsequent regeneration process. At the same time, the accelerator used in the hydrogen pretreatment process can also help remove metal elements and heteroatoms from the waste lubricating oil, which is beneficial to improving the quality of the subsequently regenerated lubricating oil.

[0042] (3) In this disclosure, waste lubricating oil, hydrogen pretreatment catalyst and accelerator are mixed into a slurry as liquid phase feed, which can effectively improve the dispersion of hydrogen pretreatment catalyst and improve its catalytic performance.

[0043] (4) The oil-soluble catalyst used in the method disclosed herein has good dispersion performance, which is conducive to the catalyst being better and more uniformly dispersed in the waste lubricating oil, and to better contact the additive macromolecules for reaction. It also has adsorption performance, thereby improving the reaction effect of waste oil pretreatment to remove impurities and solidify impurities, and is conducive to further improving the yield of liquid phase products in hydrogen pretreatment.

[0044] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0045] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 This is a schematic flowchart of one specific implementation of the waste lubricating oil hydrogen pretreatment system disclosed herein;

[0047] Figure 2 This is a schematic flowchart of another specific implementation of the waste lubricating oil hydrogen pretreatment system disclosed herein;

[0048] Figure 3 This is a schematic flowchart of another specific embodiment of the waste lubricating oil hydrogen pretreatment system disclosed herein.

[0049] Explanation of reference numerals in the attached figures

[0050] 1. Raw material mixing unit; 2. Raw material preheating furnace; 3. Hydrogen preheating furnace

[0051] 4. Slurry bed; 5. Hot high-pressure separator; 6. Cold high-pressure separator

[0052] 7. Cold low-pressure separator; 8. Hot low-pressure separator; 9. Solid-liquid separation device.

[0053] 10. Hydrogen separator Detailed Implementation

[0054] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0055] In this disclosure, unless otherwise stated, directional terms such as "up," "down," "left," and "right" generally refer to "up," "down," "left," and "right" when the system of this disclosure is functioning normally.

[0056] The first aspect of this disclosure provides a method for pretreating waste lubricating oil, the method comprising: S1, subjecting a mixed slurry to hydrotreating in a slurry bed to obtain a hydrogenated mixture; wherein the mixed slurry contains waste lubricating oil, a hydrotreating catalyst, and an accelerator; the hydrotreating catalyst comprises an oil-soluble catalyst and / or a carbon-supported catalyst; the accelerator comprises a sulfur-containing substance and an alkaline solution; the amount of the hydrotreating catalyst, calculated as metal element, relative to 1g of waste lubricating oil is 20-100000μg, and the weight ratio of the accelerator to the amount of the hydrotreating catalyst, calculated as metal element, is (0.4-200):1; S2, separating the hydrogenated mixture to obtain a gaseous material, a distillate oil, and a catalyst-containing tail oil.

[0057] In existing technologies, heavy oil hydrotreating typically aims to hydrogenate and convert hydrocarbons in the >280℃ distillation range of heavy oil as much as possible. However, the method disclosed in this invention, by contacting waste lubricating oil with a specific hydrogenation pretreatment catalyst and promoter in a slurry bed for hydrogenation pretreatment, can remove heteroatoms and metal elements from the waste lubricating oil while minimizing the conversion rate of the lubricating oil base oil fraction (280-520℃) and maximizing the lightening of the >520℃ fraction. This is beneficial for improving the yield of the lubricating oil base oil fraction obtained from subsequent regeneration processes and the quality of the regenerated lubricating oil.

[0058] In this disclosure, the weight ratio of sulfur-containing substances to alkaline solutions can vary within a wide range. In one specific embodiment of this disclosure, in step S1, the weight ratio of the sulfur-containing substances to the alkaline solutions is 1:(0.1-300), preferably 1:(0.5-250). In this embodiment, the appropriate weight ratio of sulfur-containing substances to alkaline solutions is beneficial for further removing metal elements and heteroatoms from waste lubricating oil and effectively improving the yield of lubricating oil fractions.

[0059] In one specific embodiment of this disclosure, the amount of the hydropretreatment catalyst, calculated based on metal elements, is 50-5000 μg, preferably 100-3000 μg, relative to 1g of waste lubricating oil; the weight ratio of the promoter to the hydropretreatment catalyst, calculated based on metal elements, is (0.6-150):1, more preferably (0.6-20):1. In this embodiment, the liquid phase yield and the effect of removing heteroatoms and metal elements from waste lubricating oil can be further improved.

[0060] In one specific embodiment of this disclosure, in step S1, the accelerator further contains a calcium-containing inorganic compound; the amount of the calcium-containing inorganic compound relative to 1g of waste lubricating oil can vary within a wide range, for example, it can be 0.001-0.03g; preferably, the calcium-containing inorganic compound includes one or more of calcium carbonate, calcium oxide, and calcium hydroxide. In this embodiment, the removal effect of heteroatoms such as chlorine atoms in waste lubricating oil can be further improved, which is beneficial to further improving the quality of subsequent regenerated lubricating oil.

[0061] According to this disclosure, in step S1, the sulfur-containing substance is selected from one or more of sublimed sulfur, carbon disulfide, dimethyl sulfide, and sulfur-containing low-element gas; the alkaline solution is selected from sodium hydroxide solution and / or potassium hydroxide solution, more preferably aqueous sodium hydroxide solution and / or aqueous potassium hydroxide solution, and the concentration of the alkaline solution can vary in a wide range, for example, it can be 0.5-20% by weight.

[0062] According to this disclosure, the mixed slurry is a preheated slurry. In one specific embodiment of this disclosure, in step S1, the temperature of the mixed slurry is 20-200℃, preferably 40-150℃;

[0063] In one specific embodiment of this disclosure, waste lubricating oil, hydrogen pretreatment catalyst, and accelerator are introduced into a raw material mixing unit for mixing to obtain a mixed slurry containing waste lubricating oil, hydrogen pretreatment catalyst, and accelerator.

[0064] In one specific embodiment of this disclosure, the conditions for the hydrogen pretreatment include a reaction temperature of 300-480℃, preferably 350-410℃; a reaction pressure of 2-20 MPa, preferably 4-12 MPa; and a liquid hourly space velocity of 0.2-4 h⁻¹. -1 Preferably 0.25-2h -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 3 200-3000Nm 3 / m 3 In this embodiment, by further optimizing the reaction conditions for hydrogen pretreatment and combining them with a carbon-supported catalyst and / or an oil-soluble catalyst, the conversion rate of the lubricating oil base oil fraction (280-520°C) in the waste lubricating oil can be minimized, which is beneficial to further improving the yield of the lubricating oil base oil fraction obtained from the subsequent regeneration process.

[0065] In one specific embodiment of this disclosure, the oil-soluble catalyst 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 oil-soluble catalyst 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 oil-soluble catalyst has high hydrogenation activity. When used for the hydrogenation treatment of waste lubricating oil, the coordinating groups of the organic ligands in the oil-soluble catalyst 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. It can obtain a high feedstock cracking rate and a heteroatom removal rate, thereby improving the reaction effect of impurity removal and solidification in waste oil pretreatment, which is conducive to further improving the yield of liquid phase products in hydrogenation pretreatment.

[0066] In one specific embodiment of this disclosure, in step S1, based on the dry weight of the oil-soluble catalyst, the metal content in the oil-soluble catalyst is 2-40% by weight, preferably 2-35%, more preferably 8-30%, and even 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 even 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, and 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 oil-soluble catalyst 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 oil-soluble catalyst can be highly dispersed in the oil phase, such as oil-soluble molybdenum catalysts, oil-soluble molybdenum-cobalt catalysts, oil-soluble molybdenum-nickel catalysts, oil-soluble iron-molybdenum catalysts, and oil-soluble iron-zinc catalysts. In one specific embodiment of this disclosure, the oil-soluble catalyst can be an oil-soluble catalyst such as iron naphthenate or iron carboxylate.

[0071] In one specific embodiment of this disclosure, the carbon-supported catalyst comprises a carbon-based support and an active metal component; based on the total weight of the carbon-supported catalyst and calculated by metal element, the content of the active metal component is 1-50% by weight, preferably 5-40% by weight, more preferably 20-40% by weight; the carbon-based support comprises carbon-containing materials with a carbon content greater than 80% by weight, and the carbon-based support may include, but is not limited to, carbon black, activated carbon, coal powder, deoiled asphalt, etc.; the metal element in the active metal component includes one or more of Fe, Co, Mo, W and Ni, and preferably, the active metal component includes metal oxides.

[0072] like Figure 1 As shown, in another specific embodiment of this disclosure, step S1 includes: SS1, introducing hydrogen into a hydrogen preheating furnace for preheating to obtain preheated hydrogen; SS2, introducing the mixed slurry into a raw material preheating furnace for heating, and introducing the obtained preheated material and the preheated hydrogen into the slurry bed for the hydrogen pretreatment.

[0073] like Figure 2 As shown, in one specific embodiment of this disclosure, step S1 includes: SS1, introducing hydrogen into a hydrogen preheating furnace for preheating to obtain preheated hydrogen; SS2, introducing the preheated hydrogen and the mixed slurry into a raw material preheating furnace for heating, and introducing the obtained preheated material into the slurry bed for the hydrogen pretreatment.

[0074] like Figure 3 As shown, in another specific embodiment of this disclosure, step S1 includes: SS1, introducing hydrogen into a hydrogen preheating furnace for preheating to obtain preheated hydrogen; SS2, introducing a portion of the preheated hydrogen and the mixed slurry into a raw material preheating furnace for heating, and introducing the obtained preheated material and the remaining portion of the preheated hydrogen into the slurry bed for the hydrogen pretreatment. Optionally, the preheated hydrogen introduced into the raw material preheating furnace accounts for 1-50% of the total volume of the preheated hydrogen. In this embodiment, by introducing preheated hydrogen into the slurry bed before and after the raw material preheating furnace, the problem of coking in the raw material preheating furnace can be effectively avoided while minimizing hydrogen consumption.

[0075] In one specific embodiment of this disclosure, the method further includes step S3: mixing a portion of the catalyst-containing tail oil with the mixed slurry and then introducing it into the slurry bed; the amount of the catalyst-containing tail oil introduced into the slurry bed as a percentage of the total amount of the catalyst-containing tail oil can vary within a wide range, for example, it can be 5-40% by weight, preferably 10-30% by weight. In this embodiment, by recycling a portion of the catalyst-containing tail oil, the utilization rate of the hydrotreating catalyst can be further improved.

[0076] In one specific embodiment of this disclosure, step S2 includes: SS1, introducing the hydrogenated mixture into a hot high-pressure separator for a first separation to obtain a gaseous component and a liquid component; SS2, introducing the gaseous component into a cold high-pressure separator for a second separation, introducing the gaseous component obtained from the second separation into a cold low-pressure separator for a third separation, introducing the gaseous component obtained from the third separation into a hydrogen separator for a fourth separation, and introducing the hydrogen obtained from the fourth separation into the slurry bed; introducing the liquid component into a hot low-pressure separator for a fifth separation, and performing solid-liquid separation on the liquid component obtained from the fifth separation. In this embodiment, by subjecting the hydrogenated mixture to multiple gas-liquid separations combined with solid-liquid separation, hydrogen can be recycled and reused, and distillate oil can be separated, thus improving the hydrogen utilization rate of the method of this application.

[0077] In this disclosure, solid-liquid separation is well known to those skilled in the art, and may include, for example, one or more combinations of filtration separation, centrifugal separation, and membrane separation.

[0078] like Figures 1-3 As shown, the method provided in the first aspect of this disclosure can be carried out in a waste lubricating oil pretreatment system, the system comprising: a raw material mixing unit 1, a slurry bed 4, and a separation unit; wherein, the slurry bed 4 is provided with a hydrogen pretreatment catalyst, the hydrogen pretreatment catalyst comprising an oil-soluble catalyst and / or a carbon-supported catalyst; the outlet of the raw material mixing unit 1 is connected to the raw material inlet of the slurry bed 4, and the product outlet of the slurry bed 4 is fluidly connected to the inlet of the separation unit 1.

[0079] The system disclosed herein can perform hydrogen pretreatment of waste lubricating oil. This system can remove most of the chlorine and heavy metals from the waste lubricating oil, which is beneficial for protecting the hydrogenation catalyst in the subsequent lubricating oil regeneration process and improving the operating cycle of the waste lubricating oil regeneration system.

[0080] According to this disclosure, the raw material mixing unit may be, for example, a mixing feed tank.

[0081] In one specific embodiment of this disclosure, the system further includes a hydrogen preheating furnace 3 and a raw material preheating furnace 2; the outlet of the raw material mixing unit 1 is fluidly connected to the inlet of the raw material preheating furnace 2, the outlet of the raw material preheating furnace 2 is fluidly connected to the raw material inlet of the slurry bed 4, and the product outlet of the slurry bed 4 is fluidly connected to the inlet of the separation unit; the outlet of the hydrogen preheating furnace 3 is fluidly connected to the inlet of the raw material preheating furnace 2, or the outlet of the hydrogen preheating furnace 3 is in flow communication with the inlet of the slurry bed 4 and optionally fluidly connected to the inlet of the raw material preheating furnace 2.

[0082] In one specific embodiment of this disclosure, the separation unit includes: a hot high-pressure separator 5, a cold high-pressure separator 6, a cold low-pressure separator 7, a hydrogen separator 10, a hot low-pressure separator 8, and a solid-liquid separation device 9; the outlet of the slurry bed 4 is fluidly connected to the inlet of the hot high-pressure separator 5, the gas phase outlet of the hot high-pressure separator 5 is fluidly connected to the inlet of the cold high-pressure separator 6, the gas phase outlet of the cold high-pressure separator 6 is fluidly connected to the inlet of the cold low-pressure separator 7, the gas phase outlet of the cold low-pressure separator 7 is fluidly connected to the inlet of the hydrogen separator 10, and the hydrogen outlet of the hydrogen separator 10 is fluidly connected to the inlet of the slurry bed 4; the liquid phase outlet of the hot high-pressure separator 5 is fluidly connected to the inlet of the hot low-pressure separator 8, the liquid phase outlet of the hot low-pressure separator 8 is fluidly connected to the inlet of the solid-liquid separation device 9, and the catalyst-containing tail oil outlet of the solid-liquid separation device 9 may optionally be fluidly connected to the inlet of the raw material mixing unit 1.

[0083] In a preferred embodiment of this disclosure, the hydrogen outlet of the hydrogen separator 10 is in fluid communication with the inlet of the hydrogen preheating furnace 3, and the outlet of the hydrogen preheating furnace 3 is in fluid communication with the inlet of the raw material preheating furnace 2; or, the outlet of the hydrogen preheating furnace 3 is in flow communication with the inlet of the slurry bed 4 and optionally in fluid communication with the inlet of the raw material preheating furnace 2.

[0084] The present disclosure will be further illustrated by the following examples, but the present disclosure is not limited thereto.

[0085] 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. The sodium hydroxide solution used in the following examples had a concentration of 10% by weight, and the potassium hydroxide solution had a concentration of 5% by weight.

[0086] Table 1 Properties of waste lubricating oil

[0087]

[0088]

[0089] The preparation method of the main agent and reaction raw materials of the oil-soluble catalyst used in the examples 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 oil-soluble catalyst.

[0090] Table 2

[0091]

[0092] The carbon-supported catalyst D1 used in the examples was prepared by the following method:

[0093] (1) Preparation of carrier: Activated carbon (carbon content of more than 95% by weight) is dried and dehydrated at 120℃ and then pulverized into powder with a particle size of 20-60μm;

[0094] (2) Using Fe2(SO4)3 to prepare an aqueous solution of ferric sulfate as the metal source solution, the Fe content in the aqueous solution of ferric sulfate is 2.4g relative to 100mL of active metal source solution; after mixing 125mL of aqueous solution of ferric sulfate with 5g of carrier evenly, 20.16g of 28wt% ammonia solution is added while stirring to carry out precipitation reaction; the precipitation reaction conditions are: reaction temperature of 60℃ and reaction time of 60min; after washing the precipitate, the precipitate reaction product is subjected to solid-liquid separation to obtain solid material;

[0095] (3) After drying the solid material at 110℃ for 300 min, it was placed in a tube furnace and calcined at 490℃ for 300 min under N2 gas protection to obtain carbon-supported catalyst D1, the properties of which are shown in Table 3.

[0096] Table 3 Properties of carbon-supported catalyst D1

[0097] Fe, weight % <![CDATA[Specific surface area, m 2 / g]]> Particle size, μm metallic phase Metal particle size, nm D1 35.40 50.3 24.5 <![CDATA[Fe3O4]]> 22.37

[0098] Example 1

[0099] like Figure 3 As shown, the method for hydrogen pretreatment of waste lubricating oil includes:

[0100] S1. Waste lubricating oil, hydrogen pretreatment catalyst and accelerator are introduced into the raw material mixing unit for mixing to obtain a mixed slurry containing waste lubricating oil, hydrogen pretreatment catalyst and accelerator;

[0101] Hydrogen gas is introduced into a hydrogen preheating furnace for preheating to obtain preheated hydrogen gas.

[0102] A portion of the preheated hydrogen and the mixed slurry are introduced into the raw material preheating furnace for heating, and the resulting preheated material and the remaining preheated hydrogen are introduced into the slurry bed for hydrogen pretreatment.

[0103] S2. The hydrogenated mixture is introduced into a hot high-pressure separator for the first separation to obtain gaseous and liquid components.

[0104] The gas phase component is introduced into a cold high-pressure separator for a second separation. The gas phase component obtained from the second separation is introduced into a cold low-pressure separator for a third separation. The gas phase component obtained from the third separation is introduced into a hydrogen separator for a fourth separation. The hydrogen obtained from the fourth separation is introduced into a slurry bed via a hydrogen preheating furnace. The liquid phase component is introduced into a hot low-pressure separator for a fifth separation. The liquid phase component obtained from the fifth separation undergoes solid-liquid separation.

[0105] The reaction conditions, product results, and product property analysis results for the above steps are shown in Table 4.

[0106] Example 2-11

[0107] Waste lubricating oil pretreatment was carried out using the same method as in Example 1, except that the reaction conditions were different, as shown in Table 4.

[0108] Example 12

[0109] Waste lubricating oil pretreatment was performed using the same method as in Example 1, except that, as Figure 1 As shown, in step S1, the mixed slurry is introduced into the raw material preheating furnace for heating, and the resulting preheated material and preheated hydrogen are introduced into the slurry bed for the hydrogen pretreatment.

[0110] Example 13

[0111] Waste lubricating oil pretreatment was performed using the same method as in Example 1, except that, as Figure 2 As shown, in step S1, preheated hydrogen and mixed slurry are introduced into the raw material preheating furnace for heating, and the resulting preheated material is introduced into the slurry bed for hydrogen pretreatment.

[0112] Comparative Example 1

[0113] Waste lubricating oil pretreatment was carried out using the same method as in Example 1, except that step S1 was non-hydrogen-exposed and no hydrogenation catalyst or accelerator was used.

[0114] Comparative Example 2

[0115] Waste lubricating oil pretreatment was performed using the same method as in Example 1, except that step S1 did not contain an accelerator.

[0116] Comparative Example 3

[0117] Waste lubricating oil pretreatment was performed using the same method as in Example 1, except that the accelerator in step S1 did not contain an alkaline solution.

[0118] Table 4

[0119]

[0120]

[0121] In the table, the amount of hydrogen pretreatment catalyst (μg / g) refers to the amount of oil-soluble catalyst, calculated as metal element, or the amount of carbon-supported catalyst, calculated as metal element, relative to 1g of the waste lubricating oil.

[0122] The amount of accelerator used (μg / g) refers to the amount of accelerator used relative to 1g of the waste lubricating oil.

[0123] Hydrogen consumption / % refers to the amount of hydrogen used relative to 1g of the waste lubricating oil.

[0124] The percentage of circulating tail oil (by weight) refers to the proportion of catalyst-containing tail oil introduced into the slurry bed to the total amount of catalyst-containing tail oil.

[0125] The percentage of preheated hydrogen introduced before the raw material preheating furnace (by volume) refers to the proportion of preheated hydrogen introduced into the raw material preheating furnace to the total amount of preheated hydrogen.

[0126] As can be seen from the above, the method disclosed herein can remove most of the chlorine and heavy metals while ensuring high liquid yield, and can provide high-quality pre-treated raw materials for subsequent fixed bed units.

[0127] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0128] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0129] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for pretreating waste lubricating oil, the method comprising: S1. The mixed slurry is subjected to hydrogenation pretreatment in a slurry bed to obtain a hydrogenated mixture; The mixed slurry contains waste lubricating oil, hydrogen pretreatment catalyst, and accelerator; The hydrogen pretreatment catalyst includes an oil-soluble catalyst and / or a carbon-supported catalyst; the promoter includes a sulfur-containing substance and an alkaline solution; the amount of the hydrogen pretreatment catalyst, calculated as metal element, is 20-100000 μg relative to 1g of waste lubricating oil, and the weight ratio of the promoter to the amount of the hydrogen pretreatment catalyst, calculated as metal element, is (0.4-200):

1. S2. Separate the hydrogenated mixture to obtain gaseous material, distillate oil and catalyst-containing tail oil.

2. The method according to claim 1, wherein, In step S1, the weight ratio of the sulfur-containing substance to the alkaline solution is 1:(0.1-300), preferably 1:(0.5-250).

3. The method according to claim 1, wherein, In step S1, the amount of the hydrogen pretreatment catalyst, calculated as metal element, relative to 1g of waste lubricating oil is 50-50000μg, preferably 100-3000μg, and the weight ratio of the promoter to the amount of the hydrogen pretreatment catalyst, calculated as metal element, is (0.6-150):

1.

4. The method according to claim 1, wherein, In step S1, the accelerator also contains a calcium-containing inorganic compound; the amount of the calcium-containing inorganic compound is 0.001-0.03g relative to 1g of waste lubricating oil. Preferably, the calcium-containing inorganic compound includes one or more of calcium carbonate, calcium oxide, and calcium hydroxide.

5. The method according to claim 1, wherein, In step S1, the sulfur-containing substance is selected from one or more of sublimed sulfur, carbon disulfide, dimethyl sulfide, and sulfur-containing low-element gas; The alkaline solution is selected from sodium hydroxide solution and / or potassium hydroxide solution, and the concentration of the alkaline solution is 0.5-20% by weight.

6. The method according to claim 1, wherein, In step S1, the temperature of the mixed slurry is 20-200℃, preferably 40-150℃; The conditions for the hydrogen pretreatment include: a reaction temperature of 300-480℃, preferably 350-410℃; a reaction pressure of 2-20 MPa, preferably 4-12 MPa; and a liquid hourly space velocity of 0.2-4 h⁻¹. -1 Preferably 0.25-2h -1 The volume ratio of hydrogen to the waste lubricating oil is 100-3000 Nm³. 3 / m 3 Preferably 200-3000 Nm 3 / m 3 .

7. The method according to claim 1, wherein, The oil-soluble catalyst contains 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 oil-soluble catalyst 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.

8. The method according to claim 7, wherein, Based on the dry weight of the oil-soluble catalyst, the metal content in the oil-soluble catalyst is 2-40% by weight, preferably 2-35%, more preferably 8-30%, and even 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.

9. The method according to claim 1, wherein, The carbon-supported catalyst comprises a carbon-based support and an active metal component; based on the total weight of the carbon-supported catalyst and calculated by metal element, the content of the active metal component is 1-50% by weight, preferably 2-40% by weight. The carbon-based carrier comprises carbon-containing materials with a carbon content greater than 80% by weight; the metal elements in the active metal component include one or more of Fe, Co, Mo, W and Ni.

10. The method according to claim 1, wherein, Step S1 includes: SS1. Hydrogen gas is introduced into a hydrogen preheating furnace for preheating to obtain preheated hydrogen gas; SS2, The preheated hydrogen and the mixed slurry are introduced into the raw material preheating furnace for heating, and the resulting preheated material is introduced into the slurry bed for the hydrogen pretreatment; or, A portion of the preheated hydrogen gas and the mixed slurry are introduced into a raw material preheating furnace for heating. The resulting preheated material, along with the remaining portion of the preheated hydrogen gas, is then introduced into the slurry bed for the hydrogen pretreatment. Optionally, the preheated hydrogen gas introduced into the raw material preheating furnace accounts for 1-50% by volume of the total preheated hydrogen gas. The mixed slurry is introduced into a raw material preheating furnace for heating, and the resulting preheated material and the preheated hydrogen are introduced into the slurry bed for hydrogen pretreatment.

11. The method according to claim 1, wherein, The method further includes step S3: mixing a portion of the catalyst-containing tail oil with the mixed slurry and then introducing it into the slurry bed; Preferably, the amount of catalyst-containing tail oil introduced into the slurry bed accounts for 5-40% by weight of the total amount of catalyst-containing tail oil.

12. The method according to claim 1, wherein, Step S2 includes: SS1. The hydrogenated mixture is introduced into a hot high-pressure separator for the first separation to obtain a gas phase component and a liquid phase component; SS2. The gas phase component is introduced into a cold high-pressure separator for a second separation, the gas phase component obtained from the second separation is introduced into a cold low-pressure separator for a third separation, the gas phase component obtained from the third separation is introduced into a hydrogen separator for a fourth separation, and the hydrogen obtained from the fourth separation is introduced into the slurry bed. The liquid phase component is introduced into a thermal low-pressure separator for a fifth separation, and the liquid phase component obtained from the fifth separation is subjected to solid-liquid separation.

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