Impurity removal method and regeneration treatment process for waste lubricating oil

Abstract

The invention discloses a waste lubricating oil impurity removal method and a regeneration treatment process, and the impurity removal method comprises the following steps: a waste lubricating oil raw material enters a first membrane separation zone, and is treated to obtain a penetrating fluid and a retentate; the obtained penetrating fluid enters a heat treatment reaction zone, and a gas-phase material flow and a reaction product material flow are obtained after treatment; and mixing the obtained reaction product flow with water, and treating the mixture in a second membrane separation area to obtain the primarily purified waste lubricating oil raw material. According to the regeneration treatment process, a waste lubricating oil pretreatment technology for efficiently removing impurities is combined with a hydrotreating-isodewaxing-finishing two-stage high-pressure hydrogenation upgrading process; the problems of short operation cycle of a downstream hydrogenation upgrading device, hidden danger of corrosion of a hydrogenation device and the like caused by the existence of chlorine and metal in the waste lubricating oil are solved, and the quality of a regenerated product of the waste lubricating oil can be greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of petrochemicals and relates to a method for treating waste lubricating oil, particularly a method for treating waste lubricating oil by pretreatment to remove impurities and then hydrogenation to improve its quality. Background Technology

[0002] Mineral oil is currently the most widely used chemical substance worldwide. However, if the waste oil generated after its use is not properly treated, it will cause serious pollution to water bodies and soil, harm the growth of animals and plants, and the human living environment. It has been listed by the state as a high-risk waste chemical (HW08) for priority protection and treatment. Currently, the market capacity of waste lubricating oil in my country is approximately 8 million tons. This waste lubricating oil is not being effectively recycled, causing serious environmental pollution and wasting valuable petroleum resources. Less than 10% of waste lubricating oil is deteriorated; through high-tech methods and harmless treatment processes, it can be used to produce heavy fuel oil and lubricating oil base oil for industrial power. The comprehensive utilization of waste mineral oil is of great significance for alleviating my country's resource shortage, solving the bottleneck problem of oil supply falling short of demand, improving the utilization rate of existing resources, and protecting the ecological environment.

[0003] Currently, the common domestic method for treating waste lubricating oil is a combination of distillation pretreatment and hydrogenation treatment. Distillation pretreatment is simple and easy to implement, but problems such as equipment blockage and corrosion seriously affect the long-term stable operation of the equipment.

[0004] CN107325839A proposes a waste lubricating oil regeneration method employing hydro-catalytic thermal treatment, hydrorefining, and fractionation. However, this hydro-thermal treatment cannot effectively remove impurities such as chlorine, phosphorus, and metals, which significantly affect the subsequent hydrorefining catalyst. Furthermore, the improvement in waste lubricating oil quality achieved solely through hydrorefining is limited.

[0005] CN106350112A discloses a method for pretreatment of waste mineral oil followed by hydrotreating to regenerate lubricating oil base oil. The proposed method uses a process of sedimentation dehydration, centrifugal separation, thin-film evaporation, and vacuum distillation to treat waste lubricating oil. However, the pretreatment process of sedimentation dehydration, centrifugal separation, thin-film evaporation, and vacuum distillation is not ideal for removing impurities such as chlorine, phosphorus, and metals. Furthermore, using only hydrotreating to improve the quality of the waste lubricating oil results in a base oil product of poor quality.

[0006] CN106906040A discloses a method for regenerating waste lubricating oil, which uses alumina adsorbent and chitosan derivative adsorbent to pretreat the waste lubricating oil and remove non-ideal components. However, for waste lubricating oil with complex sources, the types and quantities of impurities vary greatly, and adsorption separation alone cannot meet the impurity limits of the subsequent hydrogenation catalyst. This method also only uses a hydrogenation refining process to improve the quality of the waste lubricating oil, resulting in a base oil product of poor quality.

[0007] CN108587765A discloses a pretreatment process for regenerating high-quality base oil from waste lubricating oil, proposing a method of chemical reaction dechlorination-hydrocatalytic thermal decomposition-solvent refining to solve the problems caused by the presence of chlorine and metals in waste lubricating oil. However, this method is not effective at removing phosphorus. While the solvent refining process improves the quality of the waste lubricating oil, the resulting base oil product is of poor quality.

[0008] The existing waste lubricating oil regeneration technologies mentioned above all suffer from poor impurity removal and low quality of the lubricating oil base oil products obtained after waste lubricating oil regeneration. Summary of the Invention

[0009] To address the shortcomings of existing waste lubricating oil regeneration methods, this invention provides a waste lubricating oil impurity removal method and regeneration process. The regeneration process combines efficient waste lubricating oil pretreatment technology for impurity removal with a two-stage high-pressure hydrogenation upgrading process of hydrotreating-isomerization dewaxing-supplementary refining. This not only solves the problems of short operating cycles of downstream hydrogenation upgrading units and corrosion risks of hydrogenation units caused by the presence of chlorine and metals in waste lubricating oil, but also significantly improves the quality of waste lubricating oil regenerated products.

[0010] This invention first provides a method for removing impurities from waste lubricating oil, the method comprising the following steps:

[0011] (1) Waste lubricating oil raw material enters the first membrane separation zone for processing, and after processing, permeate and residual liquid are obtained;

[0012] (2) The permeate obtained in step (1) is processed in the heat treatment reaction zone, and after processing, a gaseous material stream and a reaction product stream are obtained.

[0013] (3) The reaction product stream obtained in step (2) is mixed with water and then enters the second membrane separation zone for processing. After processing, the pre-purified waste lubricating oil raw material is obtained.

[0014] Furthermore, as some specific implementation methods, the permeate obtained in step (1) is preferably mixed with the gaseous stream obtained in step (2) before entering the heat treatment reaction zone. After the two are fully mixed and homogeneous, they enter the heat treatment reaction zone for processing. The mixing conditions can generally be controlled as follows: the pressure (gauge pressure) is not less than 0.11 MPa, such as 0.11 MPa to 0.40 MPa, preferably 0.11 MPa to 0.25 MPa. The mixing can be carried out in a mixing tank, which can be at least one of a vertical tank or a horizontal tank.

[0015] Furthermore, as some specific implementation methods, in step (1), the membrane module in the first membrane separation zone is an inorganic membrane, and the pore size range of the inorganic membrane is 0.3nm to 500nm, preferably 10 to 80nm; furthermore, the pore size ratio of 45nm to 55nm is not less than 90%, and the pore size ratio of 45nm to 55nm refers to the proportion of the pore volume of the pore size of 45nm to 55nm to the total pore volume.

[0016] Furthermore, as some specific implementation methods, the waste lubricating oil raw material in step (1) can remove most of the metals and solid impurities in the raw material after entering the first membrane separation zone and being separated by the membrane module.

[0017] Furthermore, as some specific implementation methods, the operating temperature of the first membrane separation zone in step (1) is 50 to 200°C, preferably 120 to 160°C.

[0018] Furthermore, as some specific implementation methods, the residual liquid in the first membrane separation zone in step (1) is a concentrated liquid containing a large number of solid impurities, which can be used as fuel oil.

[0019] Furthermore, as some specific implementation methods, the waste lubricating oil raw material can be selected from one or a mixture of several of waste internal combustion engine oil, waste gear oil, waste hydraulic oil, waste turbine oil, and waste electrical insulating oil; the waste lubricating oil raw material contains additives such as ZDDP (zinc dialkyl dithiophosphate), calcium dodecylbenzene, and chlorinated paraffin; even further, the phosphorus content is 0.02wt% to 0.6wt%, the calcium content is 0.01wt% to 1.0wt%, the zinc content is 0.01wt% to 0.5wt%, and the chlorine content is 0.01wt% to 0.5wt%.

[0020] Furthermore, as some specific implementations, the heat treatment reaction zone in step (2) is provided with at least one heat treatment reactor, which is a container with a heating device at the bottom. The reaction conditions in the heat treatment reaction zone are as follows: the heat treatment pressure is 0.05MPa to 1.0MPa, and the heating temperature at the bottom of the heat treatment reactor is 200 to 400°C, preferably 250 to 300°C.

[0021] Furthermore, as some specific implementation methods, the permeate obtained in step (1) is heated to 150-200°C and then enters the heat treatment reactor. Preferably, it enters the heat treatment reactor from the upper part of the side wall of the reactor shell. After the permeate reaches the bottom of the heat treatment reactor, it begins to pyrolyze under high temperature conditions to generate gas and residue. During the downward flow, the permeate comes into countercurrent contact with the gas generated by the reaction and reacts fully. Some of the generated residue and the waste lubricating oil after pyrolysis are discharged from the bottom of the heat treatment reactor. The liquid level in the heat treatment reactor is maintained at 5%-50% of the total height of the reactor, preferably 15%-30%. The gas generated during the treatment process is discharged from the top of the heat treatment reactor and is preferably mixed with the permeate obtained in step (1).

[0022] Furthermore, as some specific implementation methods, the reaction product stream obtained in step (2) in step (3) is cooled to 25-50°C and mixed with water. The amount of water added is 0.1%-15%, preferably 5%-10%. After thorough mixing, the water-soluble salts in the reaction product stream are dissolved. The mixture then enters the second membrane separation zone for further processing. The membrane module in the second membrane separation zone is an inorganic membrane with a pore size range of 0.3nm-500nm, preferably 5nm-30nm. Furthermore, the pore size ratio of 15nm-25nm is not less than 90%. The pore size ratio of 15nm-25nm specifically refers to the proportion of the pore volume of pores with a pore size of 15nm-25nm to the total pore volume.

[0023] Furthermore, as some specific implementation methods, the operating temperature of the second membrane separation zone in step (3) is 20-90°C, preferably 30-80°C; the pressure is 0.1-2.0 MPa, preferably 0.5-0.8 MPa.

[0024] In another aspect, the present invention provides a waste lubricating oil regeneration process, the regeneration process comprising the following steps:

[0025] (1) Waste lubricating oil raw material enters the first membrane separation zone for processing, and after processing, permeate and residual liquid are obtained;

[0026] (2) The permeate obtained in step (1) is processed in the heat treatment reaction zone, and after processing, a gaseous material stream and a reaction product stream are obtained.

[0027] (3) The reaction product stream obtained in step (2) is mixed with water and then enters the second membrane separation zone for processing. After processing, the pre-purified waste lubricating oil raw material is obtained.

[0028] (4) In the presence of hydrogen, the pre-purified waste lubricating oil raw material obtained in step (3) enters the first hydrogenation reaction zone for reaction, and the reaction products are separated to obtain gas and hydrogenated refined oil.

[0029] (5) In the presence of hydrogen, the hydrotreated oil obtained in step (4) enters the second hydrogenation reaction zone for reaction, and the reaction products are separated to obtain the target product.

[0030] Furthermore, as some specific implementation methods, the permeate obtained in step (1) is preferably mixed with the gaseous stream obtained in step (2) before entering the heat treatment reaction zone. After the two are fully mixed and homogeneous, they enter the heat treatment reaction zone for processing. The mixing conditions can generally be controlled as follows: the pressure (gauge pressure) is not less than 0.11 MPa, such as 0.11 MPa to 1.0 MPa, preferably 0.11 MPa to 0.8 MPa. The mixing can be carried out in a mixing tank, which can be at least one of a vertical tank or a horizontal tank.

[0031] Furthermore, as some specific implementation methods, in step (1), the membrane module in the first membrane separation zone is an inorganic membrane, and the pore size range of the inorganic membrane is 0.3nm to 500nm, preferably 10 to 80nm; furthermore, the pore size of 45nm to 55nm accounts for not less than 90%, and the pore size of 45nm to 55nm specifically refers to the proportion of the pore volume of pores with a diameter of 45nm to 55nm to the total pore volume.

[0032] Furthermore, as some specific implementation methods, the waste lubricating oil raw material in step (1) can remove most of the metals and solid impurities in the raw material after entering the first membrane separation zone and being separated by the membrane module.

[0033] Furthermore, as some specific implementation methods, the operating temperature of the first membrane separation zone in step (1) is 50 to 200°C, preferably 120 to 160°C.

[0034] Furthermore, as some specific implementation methods, the residual liquid in the first membrane separation zone in step (1) is a concentrated liquid containing a large number of solid impurities, which can be used as fuel oil.

[0035] Furthermore, as some specific implementation methods, the waste lubricating oil raw material can be selected from one or a mixture of several of waste internal combustion engine oil, waste gear oil, waste hydraulic oil, waste turbine oil, and waste electrical insulating oil; the waste lubricating oil raw material contains additives such as ZDDP (zinc dialkyl dithiophosphate), calcium dodecylbenzene, and chlorinated paraffin; even further, the phosphorus content is 0.02wt% to 0.6wt%, the calcium content is 0.01wt% to 1.0wt%, the zinc content is 0.01wt% to 0.5wt%, and the chlorine content is 0.01wt% to 0.5wt%.

[0036] Furthermore, as some specific implementations, the heat treatment reaction zone in step (2) is provided with at least one heat treatment reactor, which is a container with a heating device at the bottom. The reaction conditions in the heat treatment reaction zone are as follows: the heat treatment pressure is 0.05MPa to 1.0MPa, and the heating temperature at the bottom of the heat treatment reactor is 200 to 400°C, preferably 250 to 300°C.

[0037] Furthermore, as some specific implementation methods, the permeate obtained in step (1) is heated to 150-200°C and then enters the heat treatment reactor. Preferably, it enters the heat treatment reactor from the upper part of the side wall of the reactor shell. After the permeate reaches the bottom of the heat treatment reactor, it begins to pyrolyze under high temperature conditions to generate gas and residue. During the downward flow, the permeate comes into countercurrent contact with the gas generated by the reaction and reacts fully. Some of the generated residue and the waste lubricating oil after pyrolysis are discharged from the bottom of the heat treatment reactor. The liquid level in the heat treatment reactor is maintained at 5%-50% of the total height of the reactor, preferably 15%-30%. The gas generated during the treatment process is discharged from the top of the heat treatment reactor and is preferably mixed with the permeate obtained in step (1).

[0038] Furthermore, as some specific implementation methods, the reaction product stream obtained in step (2) in step (3) is cooled to 25-50°C and mixed with water. The amount of water added is 0.1%-15%, preferably 5%-10%. After thorough mixing, the water-soluble salts in the reaction product stream are dissolved. The mixture then enters the second membrane separation zone for further processing. The membrane module in the second membrane separation zone is an inorganic membrane with a pore size range of 0.3nm-500nm, preferably 5nm-30nm. Furthermore, the pore size ratio of 15nm-25nm is not less than 90%. The pore size ratio of 15nm-25nm specifically refers to the proportion of the total pore volume of pores with a pore size of 15nm-25nm to the total pore volume of all pore sizes.

[0039] Furthermore, as some specific implementation methods, the operating temperature of the second membrane separation zone in step (3) is 20-90°C, preferably 30-80°C; the pressure is 0.1-2.0 MPa, preferably 0.5-0.8 MPa.

[0040] Furthermore, as some specific implementation methods, the operating conditions of the first hydrogenation reaction zone in step (4) are as follows: reaction pressure is 0.5–18.0 MPa, preferably 6.0–10.0 MPa; reaction temperature is 230–430°C, preferably 280°C–380°C; hydrogen-to-oil volume ratio is 200–1500, preferably 600:1–800:1; and volume hourly space velocity is 0.5–10.0 h⁻¹. -1 Preferably 1.0h -1 ~3.0h -1 .

[0041] Furthermore, as some specific implementations, in step (4), the reaction products of the first hydrogenation reaction zone are preferably partially recycled back to the mixing tank and mixed with the permeate obtained in step (1) and the gaseous feed stream obtained in step (2), wherein the reaction products recycled back to the mixing tank account for 5 wt% to 50 wt% of the total reaction products, preferably 10 wt% to 35 wt%.

[0042] Furthermore, as some specific implementation methods, the first hydrogenation reaction zone in step (4) is filled with a hydrorefining catalyst. The hydrorefining catalyst can be a commercially available catalyst in the field, or prepared according to methods disclosed in the field. For example, the FF series hydrorefining catalyst developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. can be selected. Generally, the hydrorefining catalyst includes a support and an active metal component, wherein the support is at least one of alumina, silicon oxide, and silicon-containing alumina; the active metal component is one or more of Group VIB and Group VIII metals, and the active metal component exists in the form of oxides; the hydrorefining catalyst should be sulfided before use to ensure that the active metal component is in a sulfided state during the reaction. The Group VIB metal is selected from Mo and / or W, and its content is 10wt% to 25wt% based on oxides; the Group VIII metal is selected from Co and / or Ni, and its content is 3wt% to 7wt% based on oxides. Furthermore, the atomic ratio of Group VIB metal to (Group VIB metal and Group VIII metal) is 0.30 to 0.70, preferably 0.45 to 0.50.

[0043] Furthermore, as some specific implementation methods, the second hydrogenation reaction zone in step (5) includes an isomerization dewaxing reaction unit and a supplementary refining reaction unit. The isomerization dewaxing reaction unit and the supplementary refining reaction unit can be set in one reactor or in different reactors. According to the direction of liquid material flow, the liquid material passes through the isomerization dewaxing reaction unit and the supplementary refining reaction unit in sequence.

[0044] Furthermore, as some specific implementation methods, the operating conditions of the isomerization dewaxing reaction unit are generally controlled as follows: reaction temperature of 200℃~400℃, preferably 280℃~360℃, hydrogen partial pressure of 0.05MPa~30MPa, preferably 3.0~15.0MPa, and volume hourly space velocity of 0.1h. -1 ~5.0h -1 Preferably 0.5h -1 ~2.0h -1 The hydrogen-to-oil volume ratio is 100:1 to 2000:1, preferably 300:1 to 1000:1.

[0045] Furthermore, as some specific implementation methods, the operating conditions of the supplementary purification reaction unit are generally controlled as follows: reaction temperature of 50℃~300℃, preferably 180℃~280℃; hydrogen partial pressure of 1.0MPa~30.0MPa, preferably 3.0~15.0MPa; and volume hourly space velocity of 0.3h⁻¹. -1 ~3.0h -1 Preferably 0.6h -1 ~1.2h -1 The hydrogen-to-oil volume ratio is 100:1 to 1500:1, preferably 300:1 to 1000:1.

[0046] Furthermore, as some specific embodiments, the isomerization dewaxing reaction unit is filled with an isomerization dewaxing catalyst, which can be a commercially available catalyst commonly used in the art, or prepared according to existing methods disclosed in the art. For example, either FIW-12 or FIW-20 isomerization dewaxing catalysts developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. can be selected.

[0047] Furthermore, as some specific implementations, the supplementary refining reaction unit is filled with an existing reducing hydrorefining catalyst, which can be a common commercial catalyst in the field or prepared according to methods disclosed in the art. For example, FMTA-2, FHDA-1, and FHJ-2 hydrorefining catalysts developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. can be selected. The hydrorefining catalyst can be a noble metal catalyst or a reduced nickel catalyst. When it is a noble metal catalyst, the active metal is one or both of Pt and Pd, and the active metal content in the catalyst is generally 0.05% to 1% by weight. When it is a reduced nickel catalyst, the active metal content is 30% to 80% by weight of oxides. The catalyst support is generally Al2O3 or Al2O3-SiO2, and may contain additives such as P, Ti, B, and Zr. Before use, the catalyst undergoes conventional reduction to ensure that the active metal for hydrorefining is in a reduced state during the reaction.

[0048] Furthermore, as some specific implementation methods, the separation in step (5) includes two processes: gas-liquid separation and fractionation. The reaction products first enter the gas-liquid separator and are separated to obtain gaseous and liquid phase materials. The liquid phase material then enters the fractionation tower for further separation to obtain the target product. The target product can be cut as needed, such as including a first lubricating oil base oil, a second lubricating oil base oil, and a third lubricating oil base oil. The cutting temperature of the first and second lubricating oil base oils is 260–290°C, preferably 270–280°C; the cutting temperature of the second and third lubricating oil base oils is 290–330°C, preferably 300–320°C; and further, the viscosity of the first lubricating oil base oil at 100°C is 3.5 mm. 2 / s~4.5mm 2 / s, the viscosity of the second lubricating oil base oil at 100℃ is 5.5mm. 2 / s~6.5mm 2 / s, the viscosity of the third lubricating oil base oil at 100℃ is 9.0 mm. 2 / s~11.0mm 2 / s.

[0049] Furthermore, as some specific implementation methods, the fractionation in step (5) can be carried out using a vacuum distillation process. The operating conditions of the vacuum distillation column are: a top pressure of 5-40 mmHg, preferably 5-15 mmHg; and a bottom temperature of 200℃-380℃, preferably 290℃-330℃. The gas-liquid separation can be carried out using any of the existing methods in the art that can achieve gas-liquid two-phase separation.

[0050] Compared with the prior art, the waste lubricating oil impurity removal method and regeneration process provided by the present invention have one or more of the following effects:

[0051] 1. During the research process, the applicant discovered that waste lubricating oil raw materials mainly contain additives such as ZDDP (zinc dialkyl dithiophosphate), calcium dodecylbenzene cyclate, and chlorinated paraffin. These additives are the main sources of chlorine, phosphorus, zinc, and calcium in waste lubricating oil. These additives can pyrolyze at certain temperatures to produce gases such as hydrogen chloride, phosphorothiols, hydrogen sulfide, and thiols, as well as precipitates such as zinc pyrothiophosphate. More importantly, the inventors discovered that under certain reaction system conditions, the hydrogen chloride, phosphorothiols, and hydrogen sulfide gases produced by the reaction can react with metals such as iron, calcium, and zinc contained in the waste lubricating oil to produce metal salts such as calcium chloride and ferric chloride, or precipitates. By circulating the pyrolysis gas, both chlorine and phosphorus impurities in the waste lubricating oil and metals such as iron, calcium, and zinc can be removed, thereby achieving effective removal of impurities such as iron, calcium, zinc, chlorine, and phosphorus that have a significant impact on the catalyst of the waste lubricating oil hydrogenation and upgrading unit.

[0052] 2. The waste lubricating oil impurity removal method provided by the present invention adopts a two-stage membrane separation treatment and heat treatment combination process to remove metal and solid impurities from waste lubricating oil raw materials. In particular, the method of pre-mixing the gas phase material flow generated by pyrolysis with the permeate after treatment in the first membrane separation zone can significantly improve the dispersion uniformity of gas in the oil phase, thereby improving the gas-liquid mass transfer efficiency and reaction efficiency of the sludge generation reaction, which is beneficial to the removal of metals such as iron, calcium and zinc from waste lubricating oil.

[0053] 3. In the waste lubricating oil regeneration process provided by the present invention, the reaction products of the first hydrogenation reaction zone are recycled back to the mixing tank and mixed with the permeate obtained in step (1) and the gaseous material obtained in step (2). The applicant found that this operation method can greatly promote the mixing degree of gaseous material and liquid material, promote the solubility of gaseous components in liquid material, promote the mass transfer efficiency of the gas and metal sludge reaction process in the heat treatment reactor, and facilitate the smooth progress of membrane separation and heat treatment of waste lubricating oil.

[0054] 4. The waste lubricating oil regeneration process provided by this invention combines efficient waste lubricating oil pretreatment technology for removing impurities with a two-stage high-pressure hydrogenation upgrading process of hydrogenation treatment-isomeric dewaxing-supplementary refining. This process can significantly improve the quality of waste lubricating oil regeneration products while solving problems such as short operating cycles of downstream hydrogenation upgrading units and corrosion risks of hydrogenation units caused by the presence of chlorine and metals in waste lubricating oil. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the waste lubricating oil regeneration process of the present invention. Detailed Implementation

[0056] The specific content and effects of the method of the present invention are illustrated below through specific embodiments. The following embodiments will further illustrate the method provided by the present invention, but do not limit the scope of the present invention.

[0057] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0058] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0059] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0060] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0061] In the context of this invention, all numerical values ​​of parameters (e.g., quantity or condition) should be understood to be modified by the term “about” in all cases, regardless of whether “about” actually appears before the numerical value.

[0062] In the context of this invention, "substantially" means that deviations that are acceptable or considered reasonable to those skilled in the art are permitted, such as deviations within ±5%, ±2%, ±1%, ±0.5%, or ±0.1%.

[0063] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this instruction manual are based on weight, and the pressure is gauge pressure.

[0064] In the context of this invention, any two or more embodiments or aspects of this invention can be arbitrarily combined, and the resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of this invention.

[0065] like Figure 1As shown, the specific process flow of the waste lubricating oil impurity removal method and regeneration process provided by the present invention is as follows: Waste lubricating oil raw material 1 first enters the first membrane separation zone 2 for filtration treatment, and after treatment, permeate 4 and first residual liquid 3 are obtained. The obtained permeate 4 is fully mixed with the gas phase material stream 7 obtained from the heat treatment reaction zone in the mixing tank 5, and then enters the heat treatment reaction zone 6 for treatment, and after treatment, gas phase material stream and reaction product material stream are obtained; wherein the first gas phase material stream 7 is recycled, and the second gas phase material stream 8 can be discharged. The reaction product material stream is mixed with water 9 and then enters the second membrane separation zone 10 for treatment, and after treatment, pre-purified waste lubricating oil raw material 12 and second residual liquid 11 are obtained. The pre-purified waste lubricating oil feedstock 12 enters the first hydrogenation reaction zone 13, where it reacts in the presence of hydrogen. Part of the reaction product 14 from the first hydrogenation reaction zone is recycled back to the mixing tank 5, while the other part enters the first gas-liquid separation zone 15 for separation, yielding hydrogen-rich gas 17 and hydrorefined oil 16. The hydrogen-rich gas 17 can then enter the mixing tank 5 to mix with the permeate 4 and the gaseous feed stream 7. After thorough mixing, it enters the heat treatment reaction zone 6 for further processing. The hydrorefined oil 16 sequentially enters the isomerization dewaxing unit 18 and the supplementary refining unit 21 in the second hydrogenation reaction zone, where it reacts in the presence of hydrogen. The reaction product 22 from the second hydrogenation reaction zone enters the second gas-liquid separation unit 23 for separation, yielding gas 25 and liquid product 24. The liquid product 24 then enters the fractionation zone 26, where fractionation yields the first lubricating oil base oil 27, the second lubricating oil base oil 28, the third lubricating oil base oil 29, and light product 30.

[0066] In the context of this invention, the properties of the waste lubricating oil raw materials used in all embodiments and comparative examples are shown in Table 1.

[0067] In the context of this invention, the membrane components of the first membrane separation zone and the membrane components of the second membrane separation zone are both tubular ceramic membranes prepared using alumina, zirconium oxide, titanium oxide and silicon oxide as supports.

[0068] In the context of this invention, the first hydrogenation reaction zone is provided with one fixed-bed hydrogenation reactor, which is filled with FF-66 hydrogenation refining catalyst; the second hydrogenation reaction zone is provided with two fixed-bed hydrogenation reactors, the first hydrogenation reactor is filled with FIW-12 isomerization dewaxing catalyst, and the second hydrogenation reactor is filled with FMTA-2 supplementary hydrogenation refining catalyst.

[0069] Table 1 Properties of Raw Materials

[0070]

[0071]

[0072] Example 1

[0073] Example 1 uses the waste lubricating oil listed in Table 1 as raw material. The main properties of the raw material are listed in Table 1. Figure 1 The process flow shown includes a mixing tank, and the reaction products from the first hydrogenation reaction zone are not recycled back to the mixing tank. The process conditions for the first membrane separation zone, second membrane separation zone, mixing tank, heat treatment reaction zone, first hydrogenation reaction zone, and second hydrogenation reaction zone are shown in Table 2. The analytical results of the pre-purified waste lubricating oil feedstock obtained after treatment in the second membrane separation zone are shown in Table 2. The properties of the final lubricating oil base oil are shown in Table 3.

[0074] Example 2

[0075] Example 2 uses the waste lubricating oil listed in Table 1 as raw material. The main properties of the raw material are listed in Table 1. Figure 1 The process flow shown includes a mixing tank. Part of the reaction products from the first hydrogenation reaction zone are recycled back to the mixing tank and mixed with the permeate obtained in step (1) and the gaseous feed stream obtained in step (2). The recycled reaction products account for 20 wt% of the total reaction products. The process conditions for the first membrane separation zone, the second membrane separation zone, the mixing tank, the heat treatment reaction zone, the first hydrogenation reaction zone, and the second hydrogenation reaction zone are shown in Table 2. The analysis results of the pre-purified waste lubricating oil raw material obtained after treatment in the second membrane separation zone are shown in Table 2. The properties of the final lubricating oil base oil are shown in Table 3.

[0076] Example 3

[0077] Example 3 uses the waste lubricating oil listed in Table 1 as raw material. The main properties of the raw material are listed in Table 1. Figure 1 The process flow shown includes a mixing tank. A portion of the reaction products from the first hydrogenation reaction zone is recycled back to the mixing tank and mixed with the permeate obtained in step (1) and the gaseous feed stream obtained in step (2). The recycled reaction products account for 30 wt% of all reaction products. The process conditions for the first membrane separation zone, the second membrane separation zone, the mixing tank, the heat treatment reaction zone, the first hydrogenation reaction zone, and the second hydrogenation reaction zone are shown in Table 2. The analysis results of the pre-purified waste lubricating oil raw material obtained after treatment in the second membrane separation zone are shown in Table 2. The properties of the final lubricating oil base oil are shown in Table 3.

[0078] Example 4

[0079] The process is basically the same as in Example 1, except that a mixing tank was not set up, and the permeate obtained in step (1) and the gaseous feed stream obtained in step (2) were not pre-mixed and directly entered the heat treatment reaction zone. The process conditions of the first membrane separation zone, the second membrane separation zone, the heat treatment reaction zone, the first hydrogenation reaction zone, and the second hydrogenation reaction zone are shown in Table 2. The analysis results of the pre-purified waste lubricating oil raw material obtained after treatment in the second membrane separation zone are shown in Table 2. The properties of the final lubricating oil base oil are shown in Table 3.

[0080] Comparative Example 1

[0081] Comparative Example 1 is basically the same as Example 1, except that a mixing tank and a heat treatment reaction zone are not set up in Comparative Example 1. Comparative Example 1 uses the waste lubricating oil listed in Table 1 as raw material, and the main properties of the raw material are listed in Table 1. The process conditions of the first membrane separation zone, the second membrane separation zone, the first hydrogenation reaction zone, and the second hydrogenation reaction zone are shown in Table 3. The analysis results of the pre-purified waste lubricating oil raw material obtained after treatment in the second membrane separation zone are shown in Table 3.

[0082] Comparative Example 2

[0083] Comparative Example 2 is basically the same as Example 1, except that a first membrane separation zone is not set up in Comparative Example 2. Comparative Example 2 uses the waste lubricating oil listed in Table 1 as raw material, and the main properties of the raw material are listed in Table 1. The process conditions for the second membrane separation zone, mixing tank, heat treatment reaction zone, first hydrogenation reaction zone, and second hydrogenation reaction zone are shown in Table 3. The analytical results of the pre-purified waste lubricating oil raw material obtained after treatment in the second membrane separation zone are shown in Table 3.

[0084] Comparative Example 3

[0085] Comparative Example 3 is basically the same as Example 1, except that a second membrane separation zone is not set up in Comparative Example 3. Comparative Example 2 uses the waste lubricating oil in Table 1 as raw material, and the main properties of the raw material are listed in Table 1. The process conditions of the first membrane separation zone, mixing tank, heat treatment reaction zone, first hydrogenation reaction zone, and second hydrogenation reaction zone are shown in Table 3. The analysis results of the pre-purified waste lubricating oil raw material obtained after treatment in the second membrane separation zone are shown in Table 3.

[0086] Table 2. Process conditions and results of Examples 1-4

[0087]

[0088]

[0089] Table 3. Process conditions and results for Comparative Examples 1-3

[0090]

[0091]

[0092]

[0093] Table 4 Properties of the base oil products in Examples 1-4

[0094] Example number Example 1 Example 2 Example 3 Example 4 crude oil Table 1 Table 1 Table 1 Table 1 First Lubricating Oil Base Oil Yield, mass % 22.31 9.78 4.66 13.23 Pour point / ℃ -60 -36 -27 -39 <![CDATA[Viscosity (100 °C), mm / s 2 > 3.521 4.021 4.489 4.261 Viscosity Index 93 112 115 110 Second Lubricating Oil Base Oil Yield, mass % 19.15 22.43 30.01 21.90 Pour point / ℃ -48 -30 -21 -33 <![CDATA[Viscosity (100 °C), mm / s 2 > 5.564 6.122 6.543 6.002 Viscosity Index 99 115 119 112 Third Lubricating Oil Base Oil Yield, mass % 32.30 39.65 44.02 36.18 Pour point / ℃ -36 -21 -15 -21 <![CDATA[Viscosity (100 °C), mm / s 2 > 9.23 10.44 10.98 9.80 Viscosity Index 107 122 125 153

Claims

1. A method for removing impurities from used lubricating oil, the method comprising the following steps: (1) subjecting a used lubricating oil feedstock to a first membrane separation zone to obtain a permeate and a retentate; (2) subjecting the permeate obtained in step (1) to a thermal treatment reaction zone to obtain a gaseous stream and a reaction product stream; (3) subjecting the reaction product stream obtained in step (2) to a second membrane separation zone after mixing with water to obtain a first purified used lubricating oil feedstock.

2. The method of claim 1, wherein the waste lubricating oil is subjected to the decontamination process at a temperature of from 50°C to 150°C. The permeate obtained in step (1) is mixed with the gaseous stream obtained in step (2) before being introduced into the thermal treatment reaction zone, and the mixture is introduced into the thermal treatment reaction zone after being thoroughly mixed; the mixing pressure is not less than 0.11 MPa.

3. The method of claim 1 wherein, In step (1), the membrane module in the first membrane separation zone is an inorganic membrane, and the pore size of the inorganic membrane ranges from 0.3 nm to 500 nm, preferably from 10 nm to 80 nm; the pore size of 45 nm to 55 nm accounts for not less than 90%.

4. The method of claim 1 wherein the waste lubricating oil is subjected to a process selected from the group consisting of acid treatment, caustic treatment, and a combination thereof. In step (1), the operating temperature of the first membrane separation zone is 50-200°C, preferably 120-160°C.

5. The method of claim 1 wherein the waste lubricating oil is subjected to a process selected from the group consisting of acid treatment, caustic treatment, and a combination thereof. The used lubricating oil feedstock is selected from one or a mixture of several of the following: used internal combustion engine oil, used gear oil, used hydraulic oil, used turbine oil, and used electrical insulation oil; the phosphorus content in the used lubricating oil feedstock is 0.02wt%-0.6wt%, the calcium content is 0.01wt%-1.0wt%, the zinc content is 0.01wt%-0.5wt%, and the chlorine content is 0.01wt%-0.5wt%.

6. The method of claim 1 wherein the waste lubricating oil is subjected to a process selected from the group consisting of acid treatment, caustic treatment, and a combination thereof. In step (2), the reaction conditions of the thermal treatment reaction zone are as follows: the thermal treatment pressure is 0.05 MPa-1.0 MPa, and the heating temperature at the bottom of the thermal treatment reactor is 200-400°C, preferably 250-300°C.

7. The method of claim 1 wherein the waste lubricating oil is a used lubricating oil. In step (1), the permeate is heated to 150-200°C before being introduced into the thermal treatment reactor, and the pyrolysis gas and residue are generated after the permeate is introduced into the thermal treatment reactor from the upper side wall of the shell of the thermal treatment reactor; part of the generated residue and the pyrolyzed used lubricating oil are discharged from the bottom of the thermal treatment reactor, and the liquid level height of the thermal treatment reactor is maintained at 5%-50% of the total height of the reactor, preferably 15%-30%; the generated gas is discharged from the top of the thermal treatment reactor, and is preferably mixed with the permeate obtained in step (1).

8. The method of claim 1 wherein, In step (3), the mixture of the reaction product stream obtained in step (2) and water after being cooled to 25-50°C is introduced into the second membrane separation zone for treatment; the membrane module in the second membrane separation zone is an inorganic membrane, and the pore size of the inorganic membrane ranges from 0.3 nm to 500 nm, preferably from 5 nm to 30 nm; the pore size of 15 nm to 25 nm accounts for not less than 90%.

9. The method of claim 1 wherein, In step (3), the operating temperature of the second membrane separation zone is 20-90°C, preferably 30-80°C; and the pressure is 0.1-2.0 MPa, preferably 0.5-0.8 MPa.

10. A process for regenerating used lubricating oil, the process comprising the following steps: (1) subjecting a used lubricating oil feedstock to a first membrane separation zone to obtain a permeate and a retentate; (2) The permeate obtained in step (1) is introduced into a thermal treatment reaction zone for treatment, and a gas phase stream and a reaction product stream are obtained after the treatment; (3) The reaction product stream obtained in step (2) is mixed with water and then introduced into a second membrane separation zone for treatment, and an initially purified waste lubricating oil raw material is obtained after the treatment; (4) The initially purified waste lubricating oil raw material obtained in step (3) is introduced into a first hydrogenation reaction zone for reaction in the presence of hydrogen, and a gas and a hydrorefined oil are obtained after the separation of the reaction product; (5) The hydrorefined oil obtained in step (4) is introduced into a second hydrogenation reaction zone for reaction in the presence of hydrogen, and a target product is obtained after the separation of the reaction product.

11. The used lubricating oil reclamation process according to claim 10, wherein, The permeate obtained in step (1) is mixed with the gas phase stream obtained in step (2) before being introduced into the thermal treatment reaction zone, and the mixture is introduced into the thermal treatment reaction zone after being fully mixed, and the mixing pressure is not less than 0.11 MPa.

12. The used lubricating oil reclamation process according to claim 10, wherein, In step (1), the membrane assembly in the first membrane separation zone is an inorganic membrane, and the pore size of the inorganic membrane ranges from 0.3 nm to 500 nm, preferably from 10 nm to 80 nm; and the pore size of 45 nm to 55 nm accounts for not less than 90%.

13. The used lubricating oil reclamation process according to claim 10, wherein, In step (1), the operating temperature of the first membrane separation zone is 50-200°C, preferably 120-160°C.

14. The used lubricating oil reclamation process according to claim 10, wherein, The waste lubricating oil raw material is selected from one or a mixture of several of waste internal combustion engine oil, waste gear oil, waste hydraulic oil, waste turbine oil, and waste electrical insulation oil; the phosphorus content in the waste lubricating oil raw material is 0.02wt%-0.6wt%, the calcium content is 0.01wt%-1.0wt%, the zinc content is 0.01wt%-0.5wt%, and the chlorine content is 0.01wt%-0.5wt%.

15. The used lubricating oil reclamation process according to claim 10, wherein, In step (2), the reaction conditions of the thermal treatment reaction zone are as follows: the thermal treatment pressure is 0.05 MPa-1.0 MPa, and the heating temperature at the bottom of the thermal treatment reactor is 200-400°C, preferably 250-300°C.

16. The used lubricating oil reclamation process according to claim 10, wherein, In step (1), the permeate is heated to 150-200°C before being introduced into the thermal treatment reactor, and the gas and residue generated by pyrolysis are preferably introduced into the thermal treatment reactor from the upper part of the shell side wall of the thermal treatment reactor; part of the generated residue and the pyrolyzed waste lubricating oil are discharged from the bottom of the thermal treatment reactor, and the liquid level height of the thermal treatment reactor is maintained at 5%-50% of the total height of the reactor, preferably 15%-30%; and the gas generated during the treatment is discharged from the top of the thermal treatment reactor, and is preferably mixed with the permeate obtained in step (1).

17. The used lubricating oil reclamation process according to claim 10, wherein, In step (3), the mixture of the reaction product stream obtained in step (2) and water is introduced into the second membrane separation zone for treatment after being cooled to 25-50°C; the membrane assembly in the second membrane separation zone is an inorganic membrane, and the pore size of the inorganic membrane ranges from 0.3 nm to 500 nm, preferably from 5 nm to 30 nm; and the pore size of 15 nm to 25 nm accounts for not less than 90%.

18. The used lubricating oil reclamation process according to claim 10, wherein, In step (3), the operating temperature of the second membrane separation zone is 20-90°C, preferably 30-80°C; and the pressure is 0.1-2.0 MPa, preferably 0.5-0.8 MPa.

19. The used lubricating oil reclamation process according to claim 10, wherein, The operating conditions of the first hydrogenation reaction zone in step (4) are as follows: the reaction pressure is 0.5-18.0 MPa, preferably 6.0-10.0 MPa; the reaction temperature is 230-430°C, preferably 280-380°C; the hydrogen / oil volume ratio is 200-1500, preferably 600:1-800:1; the volume space velocity is 0.5-10.0 h -1 , preferably 1.0 h -1 -3.0 h -1 .

20. The used lubricating oil reclamation process according to claim 10, wherein, The reaction product of the first hydrogenation reaction zone in step (4) is partially recycled back to the mixing tank for mixing with the permeate obtained in step (1) and the gas phase stream obtained in step (2), wherein the reaction product recycled back to the mixing tank accounts for 5wt%-50wt% of the total reaction product, preferably 10wt%-35wt%.

21. The used lubricating oil reclamation process according to claim 10, wherein, The first hydrogenation reaction zone is packed with a hydrofining catalyst; the second hydrogenation reaction zone comprises an isodewaxing reaction unit and a supplemental finishing reaction unit, wherein the isodewaxing reaction unit and the supplemental finishing reaction unit are arranged in one reactor or are arranged in different reactors respectively; the liquid phase material passes through the isodewaxing reaction unit and the supplemental finishing reaction unit in sequence in the direction of liquid phase material flow; the isodewaxing reaction unit is packed with an isodewaxing catalyst, and the supplemental finishing reaction unit is packed with a hydrofining catalyst.

22. The used lubricating oil reclamation process according to claim 10, wherein, The operating conditions of the isomerization dewaxing reaction unit are as follows: the reaction temperature is 200°C to 400°C, preferably 280°C to 360°C, the hydrogen partial pressure is 0.05 MPa to 30 MPa, preferably 3.0 to 15.0 MPa, the volume space velocity is 0.1 h -1 -5.0 h -1 , preferably 0.5 h -1 -2.0 h -1 , the hydrogen to oil volume ratio is 100:1 to 2000:1, preferably 300:1 to 1000:

1.

23. The used lubricating oil reclamation process according to claim 10, wherein, The operating conditions of the make-up finishing reaction unit are as follows: reaction temperature 50°C to 300°C, preferably 180°C to 280°C, hydrogen partial pressure 1.0 MPa to 30.0 MPa, preferably 3.0 to 15.0 MPa, volume space velocity 0.3 h -1 to 3.0 h -1 , preferably 0.6 h -1 to 1.2 h -1 , hydrogen to oil volume ratio 100:1 to 1500:1, preferably 300:1 to 1000:1.

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