Method for recycling, refining and remanufacturing waste lubricating oil and remanufactured lubricating oil

Abstract

The invention discloses a method for recycling, refining and remanufacturing waste lubricating oil and remanufactured lubricating oil. The preparation method comprises the following steps: carrying out ultrasonic treatment on the waste lubricating oil to prevent impurities in the waste lubricating oil from precipitating, heating and stirring, adding an organic flocculant, changing the heating and stirring time and temperature, adding an adsorbent, changing the heating and stirring time and temperature again, settling, filtering, taking supernate and distilling to obtain the waste lubricating oil. And adding the modified graphene-copper nano composite additive, and uniformly dispersing to obtain the remanufactured lubricating oil. The modified graphene and the copper nanoparticles with different morphologies are dispersed into a refined and recycled lubricating oil matrix, the dispersion stability of the modified graphene is remarkably improved, meanwhile, the copper nanoparticles with different morphologies are introduced, so that the bearing and antifriction performance of the lubricating oil in the friction process can be effectively improved, the friction coefficient can be reduced to 0.088, and the wear volume can be reduced by 50%.

Description

Technical Field

[0001] The present invention relates to the technical field of waste lubricating oil recovery and remanufacturing, and in particular to a waste lubricating oil recovery, refining and remanufacturing method and remanufactured lubricating oil. Background Art

[0002] In recent years, with the rapid development of my country's high-end equipment field, the demand for high-end lubricants for key moving parts has increased year by year. However, the amount of waste oil generated has increased accordingly, and the harm caused by waste oil to the environment has become increasingly serious. The refining and remanufacturing of waste lubricants has become a research hotspot in the field of industrial lubrication. The lubricating and friction-reducing effect components of waste lubricants are mainly base oils, which account for more than 90%. The proportion of waste and failed components generated during the use of lubricants is not high, and the prospects for recycling the effective components of waste lubricants are very broad. Therefore, research on the recovery of waste lubricants can greatly reduce the number of lubricant replacements and increase their service life, thereby achieving the goals of saving energy and protecting the environment.

[0003] At present, the existing technologies for the recovery and refining of waste lubricating oil have the following deficiencies: (1) Sulfuric acid-kaolin refining process: Using sulfuric acid as raw material for recovery and refining will produce a large amount of wastewater containing acidic substances, which is harmful to natural environmental resources such as water and soil. This technology has been abolished; (2) Hydrogenation refining process: This process has less environmental pollution, but its reaction conditions involve harsh working conditions such as high temperature and high pressure, and its energy consumption is high. At the same time, in order to ensure the effective components of the recovered lubricating oil, the proportion of the hydrorefining component oil needs to be strictly controlled. The technical difficulty is high, and this recovery and refining process still needs further improvement; (3) Distillation-kaolin refining process: Kaolin is used as an adsorbent. Due to the small particle size of the kaolin, the difficulty of filtering and recovering the lubricating oil will be increased during the refining process. (4) The friction reduction and wear resistance of the recovered refined lubricating oil is insufficient: Compared with the new lubricating oil, the lubricating oil base recovered by the currently commonly used waste lubricating oil recovery and regeneration process still has a certain gap in friction reduction and lubrication performance, and needs further remanufacturing. Summary of the invention

[0004] In order to solve the deficiencies of the above technical solutions, the object of the present invention is to provide a method for recycling, refining and remanufacturing waste lubricating oil.

[0005] Another object of the present invention is the remanufactured lubricating oil obtained by the above method.

[0006] The purpose of the present invention is achieved through the following technical solutions.

[0007] A method for recycling, refining and remanufacturing waste lubricating oil comprises the following steps:

[0008] Step 1, ultrasonically treating the waste lubricating oil to prevent precipitation of impurities in the waste lubricating oil, heating and stirring, adding an organic flocculant, changing the time and temperature of heating and stirring, adding an adsorbent, changing the time and temperature of heating and stirring again, settling, filtering, taking the supernatant and distilling, and obtaining a recovered refined lubricating oil;

[0009] Step 2, adding the modified graphene-copper nanocomposite additive to the recovered refined lubricating oil obtained in step 1, dispersing the additive evenly, and obtaining remanufactured lubricating oil.

[0010] In the above technical solution, in step 1, the ultrasonic time is 15 minutes to 30 minutes.

[0011] In the above technical solution, in step 1, after the waste lubricating oil is ultrasonicated, the heating and stirring temperature is 60° C., the heating and stirring time is 30 minutes, and the heating and stirring are performed to remove a small amount of water in the waste lubricating oil.

[0012] In the above technical scheme, in the step 1, the mass ratio of the organic flocculant to the waste lubricating oil is 1:3.5. When the mass ratio of the organic flocculant to the waste lubricating oil is less than 1:3.5, the viscosity of the waste lubricating oil is tested by a rotational rheometer, and its viscosity is relatively high, which is not easy to stir and affects the flocculation effect; when the mass ratio of the organic flocculant to the waste lubricating oil is greater than 1:3.5, by filtering the flocculated mixture, the subsequent recovery of the organic flocculant agglomerates is difficult and the purity of the lubricating oil is low.

[0013] In the above technical scheme, in step 1, the organic flocculant is isopropanol. Based on the boiling point of isopropanol, in order to ensure the activity of isopropanol and prevent isopropanol from volatilizing, after adding the organic flocculant, the heating and stirring temperature is 40°C and the time is 30 minutes. The flocculant is added to promote the formation of flocs of impurities such as coke in the waste lubricating oil to achieve solid-liquid separation.

[0014] In the above technical scheme, in step 1, the mass of the adsorbent is 60% of the mass of the waste lubricating oil. After the adsorbent is added, the heating and stirring temperature is 130°C and the heating and stirring time is 30 minutes. This temperature can promote the volatilization of part of the machine flocculant. The adsorbent is zeolite, and the particle size of the zeolite is 1 mm. Zeolite can remove impurities such as sludge and dust in the waste lubricating oil.

[0015] The sedimentation temperature is 70° C., the sedimentation time is 3 hours, and further sedimentation is required after adding the adsorbent zeolite for decolorization, which is beneficial to the separation of the adsorbent and the lubricating oil.

[0016] In the above technical solution, in step 1, the filtration is performed by suction filtration using a Buchner funnel to separate the zeolite, and the pore size of the filter paper for suction filtration is 15 to 20 μm.

[0017] In the above technical solution, in step 1, the distillation is performed by vacuum distillation, heated by an oil bath, and the distillation temperature is 70°C. The distillation is performed to remove residual organic flocculant isopropanol. The boiling point of isopropanol is 80°C at room temperature and pressure. The vacuum environment reduces the boiling point of isopropanol, so the vacuum distillation temperature is 70°C.

[0018] In the above technical solution, in step 2, the copper nanoparticles in the modified graphene-copper nanocomposite additive are spherical copper nanoparticles, lamellar copper nanoparticles and dendritic copper nanoparticles.

[0019] In the above technical solution, in step 2, the modified graphene-copper nanocomposite additive is prepared by the following steps:

[0020] Step 1, adding graphene powder to a copper nitrate solution, then adding a reducing agent, reacting at 100° C. to 140° C. for 3 to 5 hours to obtain a graphene-copper nanocomposite additive, wherein the mass ratio of the graphene powder to the reducing agent is (1 to 5): (0.1 to 0.5) by mass, and the mass fraction of the copper nitrate solution is 5% to 10%.

[0021] Step 2: adding the graphene-copper nanocomposite additive to oleylamine, ultrasonically dispersing for 5 to 10 minutes, and stirring at room temperature for 1 to 2 hours to obtain a modified graphene-copper nanocomposite additive, wherein the modified graphene-copper nanocomposite additive can improve the dispersibility of the composite additive in the recovered refined lubricating oil matrix, wherein the mass fraction of the graphene-copper nanocomposite additive and the volume fraction of oleylamine are (1 to 3): (50 to 300), the unit of the mass fraction is g, and the unit of the volume fraction is mL.

[0022] In the above technical solution, in step 2, the reducing agent is dimethylformamide, sodium citrate or ethylene glycol.

[0023] Another aspect of the present invention also includes the remanufactured lubricating oil obtained by the above method.

[0024] The advantages and beneficial effects of the present invention are:

[0025] 1. The adsorbent of the present invention uses zeolite with a particle size of 1 mm, which is quite different from the pore size of the filter paper used in filtration, thereby reducing the technical difficulty of the filtration process.

[0026] 2. The present invention disperses modified graphene and copper nanoparticles of different morphologies into a refined and recovered lubricating oil matrix. The dispersion stability of the modified graphene is significantly improved. At the same time, the introduction of copper nanoparticles of different morphologies can effectively improve the load-bearing and friction-reducing performance of the lubricating oil during the friction process. The friction coefficient can be reduced to 0.088 and the wear volume can be reduced by 50%.

[0027] 3. The present invention adds different proportions of graphene and different reducing agents to copper nitrate with different mass fractions, and reacts to obtain three copper nanoparticles with different morphologies, which can promote the formation of a copper friction chemical reaction film in the friction contact area during the friction process of the lubricating oil, effectively reduce the degree of wear, and achieve the wear-resistant properties of the remanufactured lubricating oil; in the friction process, the modified graphene sheet can be effectively peeled off in situ, effectively reduce the interface shear strength, and achieve a friction reduction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is the process flow chart of Example 1;

[0029] Figure 2 It is a scanning electron microscope image, wherein a is the modified graphene-copper nanocomposite additive of Example 1, b is the modified graphene-copper nanocomposite additive of Example 2, and c is the modified graphene-copper nanocomposite additive of Example 3.

[0030] Figure 3 It is the friction curve diagram of the remanufactured lubricating oil of Example 1 to Example 3. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0032] The waste lubricating oil in the following embodiments is the engine oil replaced after the car has traveled 5000 kilometers.

[0033] Example 1

[0034] like Figure 1-Figure 2 As shown, a method for recycling, refining and remanufacturing waste lubricating oil comprises the following steps:

[0035] Step 1, ultrasonically treat the waste lubricating oil for 15 minutes, heat and stir at 60°C for 30 minutes, add an organic flocculant, heat and stir at 40°C for 30 minutes, then add an adsorbent, heat at 130°C, stir for 30 minutes, and then settle at 70°C for 3 hours, filter using a Buchner funnel (filter paper pore size is 15-20μm), take the supernatant, vacuum distill at 70°C (using oil bath heating), and obtain a recovered refined lubricating oil matrix, the mass ratio of the organic flocculant to the waste lubricating oil is 1:3.5, the organic flocculant is isopropanol, and the mass fraction of the adsorbent in the waste lubricating oil is 60%. The adsorbent is zeolite, and the particle size of the zeolite is 1mm.

[0036] Step 2, adding the modified graphene-copper nanocomposite additive to the recovered refined lubricating oil obtained in step 1, dispersing the additive evenly, and obtaining remanufactured lubricating oil.

[0037] The modified graphene-copper nanocomposite additive is prepared by the following steps:

[0038] Step 1, adding 2g of graphene powder to a 5% copper nitrate solution by mass, and then adding 0.2g of dimethylformamide, and reacting at 100°C for 3 hours to obtain a graphene-spherical copper nanocomposite additive (graphene-spherical copper nanoparticles).

[0039] Step 2: Add 3 g of graphene-copper nanocomposite additive to 150 mL of oleylamine, perform ultrasonic dispersion for 5 minutes, and stir at room temperature for 1 hour to obtain a modified graphene-copper nanocomposite additive.

[0040] Example 2

[0041] like Figure 1-Figure 2 As shown, a method for recycling, refining and remanufacturing waste lubricating oil comprises the following steps:

[0042] Step 1, ultrasonically treat the waste lubricating oil for 15 minutes, heat and stir at 60°C for 30 minutes, add an organic flocculant, heat and stir at 40°C for 30 minutes, then add an adsorbent, heat at 130°C, stir for 30 minutes, and then settle at 70°C for 3 hours, filter using a Buchner funnel (filter paper pore size is 15-20μm), take the supernatant, vacuum distill at 70°C (using oil bath heating), and obtain a recovered refined lubricating oil matrix, the mass ratio of the organic flocculant to the waste lubricating oil is 1:3.5, the organic flocculant is isopropanol, and the mass fraction of the adsorbent in the waste lubricating oil is 60%. The adsorbent is zeolite, and the particle size of the zeolite is 1mm.

[0043] Step 2, adding the modified graphene-copper nanocomposite additive to the recovered refined lubricating oil obtained in step 1, dispersing the additive evenly, and obtaining remanufactured lubricating oil.

[0044] The modified graphene-copper nanocomposite additive is prepared by the following steps:

[0045] Step 1, adding 2g of graphene powder to a 10% copper nitrate solution by mass, and then adding 0.4g of sodium citrate, and reacting at 140°C for 5 hours to obtain a graphene-copper nanocomposite additive (graphene-lamellar copper nanoparticles).

[0046] Step 2: Add 3 g of graphene-copper nanocomposite additive to 300 mL of oleylamine, perform ultrasonic dispersion for 5 minutes, and stir at room temperature for 1 hour to obtain a modified graphene-copper nanocomposite additive.

[0047] Example 3

[0048] like Figure 1-Figure 2As shown, a method for recycling, refining and remanufacturing waste lubricating oil comprises the following steps:

[0049] Step 1, ultrasonically treat the waste lubricating oil for 15 minutes, heat and stir at 60°C for 30 minutes, add an organic flocculant, heat and stir at 40°C for 30 minutes, then add an adsorbent, heat at 130°C, stir for 30 minutes, and then settle at 70°C for 3 hours, filter using a Buchner funnel (filter paper pore size is 15-20μm), take the supernatant, vacuum distill at 70°C (using oil bath heating), and obtain a recovered refined lubricating oil matrix, the mass ratio of the organic flocculant to the waste lubricating oil is 1:3.5, the organic flocculant is isopropanol, and the mass fraction of the adsorbent in the waste lubricating oil is 60%. The adsorbent is zeolite, and the particle size of the zeolite is 1mm.

[0050] Step 2, adding the modified graphene-copper nanocomposite additive to the recovered refined lubricating oil obtained in step 1, dispersing the additive evenly, and obtaining remanufactured lubricating oil.

[0051] The modified graphene-copper nanocomposite additive is prepared by the following steps:

[0052] Step 1, adding 2g of graphene powder to a copper nitrate solution with a mass fraction of 8%, and then adding 0.3g of ethylene glycol, and reacting at 120°C for 3 to 5 hours to obtain a graphene-copper nanocomposite additive (graphene-dendritic copper nanoparticles).

[0053] Step 2: Add 3 g of graphene-copper nanocomposite additive into 200 mL of oleylamine, perform ultrasonic dispersion for 5 minutes, and stir at room temperature for 1 hour to obtain a modified graphene-copper nanocomposite additive.

[0054] The remanufactured lubricating oils prepared in Examples 1 to 3 were subjected to friction and wear tests using a ball-on-disk contact method. The results are as follows: Figure 3 As shown. Figure 3 It can be seen that the remanufactured lubricating oil of Examples 1-3 has the best friction-reducing lubrication performance, and its friction coefficient is reduced to 0.0883.

[0055] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A method for recycling, refining and remanufacturing waste lubricating oil, characterized in that: The following steps are involved: Step 1, ultrasonically treating the waste lubricating oil, heating and stirring, adding an organic flocculant, changing the time and temperature of heating and stirring, then adding an adsorbent, changing the time and temperature of heating and stirring again, settling, filtering, and distilling the supernatant to obtain recovered refined lubricating oil; Step 2, adding the modified graphene-copper nanocomposite additive to the recovered refined lubricating oil obtained in step 1, dispersing the additive evenly, and obtaining remanufactured lubricating oil.

2. The method for recycling, refining and remanufacturing waste lubricating oil according to claim 1, characterized in that: In the step 1, the ultrasonic time is 15 min to 30 min.

3. The method for recycling, refining and remanufacturing waste lubricating oil according to claim 1, characterized in that: In the step 1, after the waste lubricating oil is ultrasonicated, the heating and stirring temperature is 60° C., and the heating and stirring time is 30 minutes.

4. The method for recycling, refining and remanufacturing waste lubricating oil according to claim 1, characterized in that: In the step 1, the mass ratio of the organic flocculant to the waste lubricating oil is 1:3.

5.

5. The method for recycling, refining and remanufacturing waste lubricating oil according to claim 1, characterized in that: In the step 1, the organic flocculant is isopropanol. After the organic flocculant is added, the heating and stirring temperature is 40° C. and the time is 30 minutes.

6. The method for recycling, refining and remanufacturing waste lubricating oil according to claim 5, characterized in that: In the step 1, the mass of the adsorbent is 60% of the mass of the waste lubricating oil. After the adsorbent is added, the heating and stirring temperature is 130° C., and the heating and stirring time is 30 minutes. The adsorbent is zeolite, and the particle size of the zeolite is 1 mm. The sedimentation temperature is 70° C., and the sedimentation time is 3 hours.

7. The method for recycling, refining and remanufacturing waste lubricating oil according to claim 6, characterized in that: In the step 1, the filtration is performed using a Buchner funnel, and the pore size of the filter paper used for the filtration is 15 to 20 μm; In the step 1, the distillation is carried out by vacuum distillation and heated by an oil bath at a temperature of 70°C.

8. The method for recycling, refining and remanufacturing waste lubricating oil according to claim 1, characterized in that: In the step 2, the morphology of the copper nanoparticles in the modified graphene-copper nanocomposite additive is spherical copper nanoparticles, lamellar copper nanoparticles or dendritic copper nanoparticles.

9. The method for recycling, refining and remanufacturing waste lubricating oil according to claim 1, characterized in that: In the step 2, the modified graphene-copper nanocomposite additive is prepared by the following steps: Step 1, adding graphene powder to a copper nitrate solution, then adding a reducing agent, reacting at 100° C. to 140° C. for 3 to 5 hours to obtain a graphene-copper nanocomposite additive, wherein the mass ratio of the graphene powder to the reducing agent is (1 to 5): (0.1 to 0.5) by mass, the mass fraction of the copper nitrate solution is 5% to 10%, and the reducing agent is dimethylformamide, sodium citrate or ethylene glycol; Step 2, adding the graphene-copper nanocomposite additive to oleylamine, ultrasonically dispersing for 5 to 10 minutes, stirring at room temperature for 1 to 2 hours to obtain a modified graphene-copper nanocomposite additive, wherein the mass fraction of the graphene-copper nanocomposite additive and the volume fraction of oleylamine are (1 to 3): (50 to 300), the unit of the mass fraction is g, and the unit of the volume fraction is mL.

10. The remanufactured lubricating oil obtained by the method for recovering, refining and remanufacturing waste lubricating oil according to any one of claims 1 to 9.

Images