Waste engine oil regeneration process
By employing a process flow of flocculation, dehydration and dehydrogenation, membrane filtration, and refining and decolorization, the problems of high equipment investment, high production costs, and environmental unfriendliness in existing waste oil regeneration processes have been solved. This has enabled efficient and low-cost waste oil regeneration, improving product quality and market value.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-26
- Publication Date
- 2026-04-03
AI Technical Summary
Existing waste oil regeneration processes involve large investments in equipment, high production costs, and the solvents used are environmentally unfriendly, with low added value from byproducts.
The process involves flocculation, dehydration and dehydrogenation, membrane filtration and refining decolorization. It includes adding a demetallizing agent and a flocculant at room temperature, followed by heating and sedimentation, then separation by vacuum filtration and membrane filtration, and finally decolorization using silica gel sand. A cleaning agent is used for recycling in the silica gel sand regeneration step.
It reduces energy consumption and production costs, increases the market value of by-products, reduces environmental pollution, and ensures stable product quality that meets market demands.
Smart Images
Figure CN121780237A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of waste oil regeneration technology, and in particular to a waste oil regeneration process. Background Technology
[0002] With industrial development, the amount of waste engine oil generated is increasing daily. Waste engine oil contains a large number of harmful substances, and direct discharge will cause serious environmental pollution. Since residual oil generally contains about 0.2% to 3% sulfur, the exhaust gas produced by combustion contains sulfur dioxide, nitrogen oxides, and dust. Even after dust removal, the sulfur dioxide and nitrogen oxides are often emitted at high altitudes, leading to air pollution and exacerbating the greenhouse effect. Therefore, regenerating waste engine oil can not only reduce environmental pollution but also achieve resource recycling, which has significant economic and environmental implications.
[0003] Currently, the mainstream waste oil regeneration processes in China are mainly distillation-hydrogenation refining and distillation-solvent extraction. These two waste oil regeneration processes involve large investments, low profits, and generate secondary hazardous waste.
[0004] The distillation-hydrorefining process first removes moisture and mechanical impurities from waste engine oil through pretreatment (dehydration and impurity removal at 145℃), then performs vacuum distillation (320℃) to separate fractions with different boiling points, followed by hydrorefining. Under the action of a catalyst, impurities such as sulfur, nitrogen, and oxygen, as well as unsaturated hydrocarbons, are removed through a hydrogenation reaction, achieving decolorization and desulfurization. Finally, trace impurities are removed by adsorption filtration. While this process can produce high-quality recycled oil, it involves large equipment investment and requires high temperature, high pressure, and large amounts of hydrogen. Since the explosive limits of hydrogen in air are 4% to 75.6%, hydrogen is a flammable and explosive gas. The hydrorefining process is inherently dangerous, making it difficult for small enterprises to afford. This results in harsh operating conditions and high production costs. The byproduct, residual oil, contains high levels of mechanical impurities and ash, has a low market price, and generates volatile organic compounds at high temperatures, polluting the environment.
[0005] The distillation-solvent extraction process involves preheating waste engine oil (145°C) after preliminary dehydration and impurity removal treatment, then decomposing it in a loss-in-weight furnace. The liquid phase is then fed into a distillation column (340°C). The fractionated thinner oil is extracted with organic solvents such as petroleum ether, benzene, or methanol. Since the extracted base oil contains some solvent, the temperature needs to be raised to 205°C to distill off the solvent. The extracted solvent contains coking compounds and impurities, resulting in a very high boiling point for the solvent mixture. This makes it difficult to recover the solvent through simple distillation or extraction; instead, it requires further heating and separation in a separation unit. The solvent is then condensed and precipitated in a condenser for recycling. This process results in high energy consumption, a complex solvent recovery process, and the solvent itself poses environmental hazards. Furthermore, the residual oil produced by the distillation unit contains mechanical impurities and has a high ash content, leading to low market value and significantly reducing overall profits.
[0006] Therefore, the present invention provides a waste engine oil regeneration process. Summary of the Invention
[0007] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a waste oil regeneration process, thereby solving the technical problems of the existing waste oil regeneration process, such as harsh process conditions, high production costs, large equipment investment, environmentally unfriendly solvents, and low added value of by-products.
[0008] To achieve the above objectives, the present invention provides a waste engine oil regeneration process, which includes: Step 1: Flocculation; First, add a demetallizing agent and a flocculant to the waste engine oil at room temperature to obtain a mixture. Then, heat the mixture to the reaction temperature. After the reaction is complete, let the mixture settle to obtain the flocculated waste engine oil. Step 2: Dehydration and dehydrogenation; The flocculated waste oil is then vacuum filtered to obtain dehydrated and dehydrogenated waste oil. Step 3: Membrane filtration; Waste engine oil that has been dehydrated and dehydrogenated is permeated to obtain base oil and concentrate, with the concentrate being used as an asphalt additive product. Step 4: Refining and decolorizing; Regenerated base oil can be obtained by decolorizing the base oil using silica gel sand.
[0009] Optionally, in step 1: the reaction temperature is 80℃~100℃; the sedimentation time is 2h~5h; in step 2: the vacuum degree of vacuum filtration is −0.05Mpa~−0.09Mpa.
[0010] Optionally, the volume ratio between waste engine oil and demetallizing agent / flocculant is 1000:8~5:3~1; The preferred volume ratio between waste engine oil and demetallizing agent and flocculant is 1000:5:3.
[0011] Optionally, in step 4: the mass ratio of base oil to silica gel sand is 7~5:1.
[0012] Alternatively, the demetallizing agent may be at least one of ammonium sulfate, metaphosphate, ammonium thiocarbamate, and dodecylbenzenesulfonic acid; the flocculant may be at least one of monoammonium phosphate, acrylamide, polyvinyl alcohol, and polyoxypropylene.
[0013] Optionally, after step 4, the following may also be included: Step 5: Regeneration of silica gel sand; Step 51: Soak the saturated silica sand used for decolorization in Step 4 in a cleaning agent to obtain a mixture of saturated cleaning agent and recycled silica sand; Step 52: Separate the saturated cleaning agent and the recycled silica sand by vacuuming the mixture of saturated cleaning agent and recycled silica sand, and recycle the recycled silica sand. Step 53: The saturated cleaning agent obtained in step 52 is subjected to membrane filtration to obtain residue and regenerated cleaning agent. The residue is recycled and the regenerated cleaning agent is reused.
[0014] The soaking time is optional, ranging from 30 to 100 minutes; the vacuum level is -0.6 MPa to -0.7 MPa.
[0015] Optionally, the mass ratio between the cleaning agent and saturated silica gel sand is 6 to 3:1.
[0016] Alternatively, the cleaning agent can be petroleum ether and butyl acetate, with a mass ratio of petroleum ether to butyl acetate of 6~4:2~1.
[0017] The beneficial effects of this invention are: (1) Through the process method of the present invention, most of the water in the waste oil is removed in the flocculation step, which reduces the energy consumption generated by subsequent high-temperature dehydration. The metal removal agent removes most of the mechanical impurities, so there is no need to filter the mechanical impurities in the subsequent membrane filtration step, which reduces the utilization rate of the filter membrane and extends the service life of the filter membrane in the membrane filtration step. At the same time, the by-product asphalt additive contains less impurities, the quality is greatly improved, and the market sales price of the by-product is increased. (2) The membrane filtration step replaces the distillation of the prior art. The flocculation temperature in step 1 of this regeneration process is 80℃~100℃, the soaking time in step 51 is 30min~100min, and the vacuum degree of step 52 is -0.6Mpa~-0.7Mpa. It can be seen that the temperature involved in the waste oil regeneration process does not exceed 100℃, while the distillation of the prior art requires 320℃. Therefore, the waste oil regeneration process of the present invention greatly saves energy consumption. (3) In the silica gel sand regeneration step, the transfer of used saturated filter sand to hazardous waste enterprises for incineration is avoided, saving the high cost of incinerating hazardous waste. In addition, the recycled silica gel sand can be reused, which greatly reduces production costs. At the same time, through the rational design of flocculation, dehydration and dehydrogenation, and membrane filtration steps, unnecessary energy consumption and reagent consumption are reduced, further reducing costs. (4) The product quality is stable. The waste oil after this regeneration process can effectively remove mechanical impurities, residual carbon, ash and moisture. Furthermore, through the refining, decolorization and silica gel sand regeneration steps, the color index of the product is guaranteed to meet the standard. The product quality is stable and reliable, which can meet the market demand for high-quality regenerated oil. (5) Environmentally friendly: In the process of waste oil regeneration, the present invention reduces the use of solvents that are harmful to the environment, and at the same time effectively recycles and reuses the generated waste, thereby reducing environmental pollution. Attached Figure Description
[0018] Figure 1 This is a flowchart of the waste oil regeneration process of the present invention. Detailed Implementation
[0019] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.
[0020] This embodiment provides a waste engine oil regeneration process, such as... Figure 1 As shown, it includes: Step 1: Flocculation; First, add a demetallizing agent and a flocculant to the waste engine oil at room temperature, with a feed pressure not exceeding 2.0 MPa, to obtain a mixture. Then, heat the mixture to the reaction temperature. After the reaction is complete, let the mixture settle to obtain the flocculated waste engine oil. In step 1: the reaction temperature is 80℃~100℃; the sedimentation time is 2h~5h; the demetallizing agent is at least one of ammonium sulfate, metaphosphoric acid, ammonium thiocarbamate, and dodecylbenzenesulfonic acid; the flocculant is at least one of monoammonium phosphate, acrylamide, polyvinyl alcohol, and polyoxypropylene.
[0021] The principle of demetallizing agents is as follows: a measured amount of demetallizing agent is dissolved in the electrostatic desalting injection water. The water and crude oil are thoroughly mixed in a mixer, dispersing into very small droplets. At the oil-water interface, the water-soluble demetallizing agent reacts with organometallic compounds in the crude oil, causing the metal ions to ionize or form precipitates or chelates, thus dissolving or dispersing them in the water. Under the combined action of an electric field and a demulsifier, the small droplets rapidly aggregate into larger droplets and separate from the oil phase, ultimately achieving the purpose of demetallizing the crude oil.
[0022] The metal removal agent in this embodiment is chemically stable in water, not easily hydrolyzed, and has good corrosion inhibition effects, which can improve refining efficiency and help prevent equipment corrosion. It not only improves oil quality but also reduces production problems caused by metal impurities.
[0023] The principle of flocculant flocculation is mainly through adsorption, bridging or trapping, which causes suspended particles (such as silt and organic matter) in water to aggregate into large flocs, thereby accelerating sedimentation or filtration.
[0024] The flocculant in this embodiment has the advantages of fast flocculation speed, large and dense flocs, and good settling performance. In the process of treating waste engine oil, it can effectively remove suspended mechanical impurities and some heavy metal ions. Furthermore, it has good chemical stability, maintaining a relatively stable flocculation effect under different water quality conditions and treatment environments, ensuring the reliability and consistency of the treatment effect.
[0025] Step 2: Dehydration and dehydrogenation; the flocculated waste oil is vacuum filtered to obtain dehydrated and dehydrogenated waste oil; the vacuum pumping time is 2h~3h; In step 2: the vacuum degree of vacuum filtration is -0.05 MPa to -0.09 MPa.
[0026] Step 3: Membrane filtration; the dehydrated and dehydrogenated waste engine oil is permeated to obtain base oil and concentrate, with the concentrate used as an asphalt additive product; the density of the concentrate is less than 0.90 g / cm³. 3 If the freezing point is less than -40℃ and the flash point is greater than 230℃, it can be directly used as an asphalt additive product.
[0027] Step 4: Refining and decolorizing; The base oil is decolorized using silica gel sand to obtain recycled base oil. The decolorization flow rate range is 5L / min to 6L / min. In step 4: the mass ratio of base oil to silica gel sand is 7~5:1.
[0028] Step 5: Regeneration of silica gel sand; Step 51: Soak the saturated silica sand used for decolorization in Step 4 in a cleaning agent to obtain a mixture of saturated cleaning agent and recycled silica sand; Soaking time is 30-100 minutes; The mass ratio of cleaning agent to saturated silica gel sand is 6~3:1.
[0029] The cleaning agent is petroleum ether and butyl acetate; The mass ratio of petroleum ether to butyl acetate is 6~4:2~1.
[0030] The cleaning agent separates organic matter based on the principle of "like dissolves like," and then extracts oil from waste silica gel sand using the cleaning agent, followed by two extraction processes. The cleaning agent has no solubility in the silica gel matrix, avoiding structural damage; silica gel sand regeneration can effectively reduce costs; continuously promoting the reduction, resource utilization, and harmless disposal of solid waste at the source, minimizing the amount of solid waste going to landfills, and reducing the environmental impact of solid waste to a minimum.
[0031] Step 52: Separate the saturated cleaning agent and the recycled silica sand by vacuuming the mixture of saturated cleaning agent and recycled silica sand, and recycle the recycled silica sand. The mixture of saturated cleaning agent and regenerated silica gel sand was separated, and the vacuum degree was -0.6Mpa to -0.7Mpa.
[0032] Step 53: The saturated cleaning agent obtained in step 52 is subjected to membrane filtration to obtain residue and regenerated cleaning agent. The residue is recycled and the regenerated cleaning agent is reused.
[0033] The membrane used in step 53 of this invention is a nano-scale filtration membrane made of 316L material with a pore size of 1nm.
[0034] Based on the waste engine oil regeneration process of the present invention, three embodiments and two comparative examples are given below. Embodiments 1, 2, and 3 respectively regenerate and recycle waste lubricating oil, spilled oil, and tank cleaning oil. Comparative examples 1 and 2 follow the process steps of embodiment 1, but the demetallizing agent and flocculant are replaced. Specifically, the demetallizing agent and flocculant in comparative example 1 are citric acid and aluminum sulfate, respectively, while the demetallizing agent and flocculant in comparative example 2 are acetic acid and aluminum oxide, respectively.
[0035] The test methods for mechanical impurities are in accordance with GB / T511-2010, the test methods for residual carbon are in accordance with GB / T17144-1997, the test methods for ash content are in accordance with GB / T508-1985 (1990), and the test methods for moisture content are in accordance with GB / T11133-2015. Example 1
[0036] Step 1: Flocculation; At room temperature, 1000L of waste engine oil (waste lubricating oil) was added to a reactor, along with 5L of ammonium sulfate and 3L of monoammonium phosphate. The stirring device was turned on, and the stirring speed was controlled at 200 rpm. The mixture was then slowly heated to 85℃ and maintained at this temperature for 2 hours. After the reaction was completed, the mixture was transferred to a continuous settling tank, and the settling time was 3 hours. The removal rate of mechanical impurities, residual carbon, ash, and moisture reached 95.6%, yielding 980L of flocculated waste engine oil.
[0037] Step 2: Dehydration and dehydrogenation; 980L of flocculated waste engine oil was vacuum filtered at a vacuum degree of -0.08MPa for 1.5h to separate a small amount of water and light components, resulting in 950L of dehydrated and dehydrogenated waste engine oil with an open flash point of 215℃.
[0038] Step 3: Membrane filtration; The feed pressure was controlled at 0.3 MPa, and the dehydrated and dehydrogenated waste engine oil was permeated at a temperature of 60°C. 890 L of 150SN base oil (80%) and 60 L of concentrate (20%) were obtained. The concentrate met the requirements for asphalt additives.
[0039] Step 4: Refining and decolorizing; 890L of 150SN base oil (existing model of base oil) after membrane filtration was filtered through 178L of silica gel sand at a flow rate of 5L / min to obtain 886L of qualified product with a color of less than 1.
[0040] Step 5: Regeneration of silica gel sand; Step 51: The cleaning agent is a mixture of petroleum ether and butyl acetate, with a mass ratio of petroleum ether to butyl acetate of 6:1. 178L of saturated silica sand used for decolorization in step 4 is soaked in 534L of the cleaning agent for 60 minutes to obtain 712L of a mixture of saturated cleaning agent and recycled silica sand. Step 52: Separate and recover 538L of saturated cleaning agent using a vacuum system. The vacuum level is -0.6Mpa. 174L of recycled silica gel sand can be reused. Step 53: 538L of saturated cleaning agent is filtered through a membrane to obtain residue and regenerated cleaning agent. The residue is recycled and treated, and 480.6L of regenerated cleaning agent is recycled and reused, with a cleaning agent recycling rate of 90%. Example 2
[0041] Step 1: Flocculation; At room temperature, 1500L of waste engine oil (oil spilled on the ground) was added to a reaction vessel, along with 8L of ammonium sulfate and 5L of monoammonium phosphate. The stirring speed was 250r / min, and the mixture was heated to 85℃ for 2.5h. After settling in a continuous settler for 4h, the removal rate of mechanical impurities, residual carbon, ash, and moisture was 97%, yielding 1475L of flocculated waste engine oil.
[0042] Step 2: Dehydration and dehydrogenation; 1475L of flocculated waste engine oil was vacuum filtered at a vacuum degree of -0.09MPa for 2 hours to obtain 1430L of dehydrated and dehydrogenated waste engine oil with an open flash point increased to 220℃.
[0043] Step 3: Membrane filtration; The feed pressure was controlled at 0.35 MPa and the permeation temperature at 60℃. The waste engine oil after dehydration and dehydrogenation was filtered through a membrane to separate 1144 L of 80% 150SN base oil and 286 L of 20% concentrate. The concentrate met the standards for asphalt additives.
[0044] Step 4: Refining and decolorizing; 1144L of 150SN base oil after membrane filtration was filtered through 228L of silica gel sand at a flow rate of 6L / min to obtain a qualified product with a color of less than 1.
[0045] Step 5: Regeneration of silica gel sand; Step 51: The cleaning agent is a mixture of petroleum ether and butyl acetate, with a mass ratio of petroleum ether to butyl acetate of 4:1. 228L of saturated silica sand used for decolorization in step 4 is soaked in 685L of the cleaning agent for 90 minutes to obtain 913L of a mixture of saturated cleaning agent and recycled silica sand. Step 52: Separate and recover 693L of saturated cleaning agent using a vacuum system. The vacuum level is -0.7Mpa. 220L of recycled silica gel sand can be reused. Step 53: 693L of saturated cleaning agent is filtered through a membrane to obtain residue and regenerated cleaning agent. The residue is recycled and treated, and 630L of regenerated cleaning agent is recycled and reused, achieving a cleaning agent recycling rate of 92%. Example 3
[0046] Step 1: Flocculation; At room temperature, 1200L of waste engine oil (cleaning and tank cleaning oil) was added to a reactor, along with 6L of ammonium sulfate and 3.6L of monoammonium phosphate. The stirring device was turned on, and the stirring speed was controlled at 200 rpm. The mixture was then slowly heated to 87℃ and maintained at this temperature for 2.2 hours. After the reaction was completed, the mixture was transferred to a continuous settling tank, where it was settling for 4 hours. The results showed that the removal rates of mechanical impurities, residual carbon, ash, and moisture reached 96.9%, yielding 1175L of flocculated waste engine oil.
[0047] Step 2: Dehydration and dehydrogenation; 1175L of flocculated waste engine oil was vacuum filtered at a vacuum degree of -0.08MPa for 1.5h to separate a small amount of water and light components, resulting in 1140L of dehydrated and dehydrogenated waste engine oil with an open flash point of 218℃.
[0048] Step 3: Membrane filtration; The feed pressure was controlled at 0.3 MPa, and the dehydrated and dehydrogenated waste engine oil was permeated at a temperature of 60°C. 912 L of 80% 150SN base oil and 228 L of 20% concentrate were obtained. The concentrate met the requirements for asphalt additives.
[0049] Step 4: Refining and decolorizing; 912L of 150SN base oil after membrane treatment was filtered through 182L of silica gel sand at a flow rate of 5L / min to obtain 905L of qualified product with a color of less than 1.
[0050] Step 5: Regeneration of silica gel sand; Step 51: The cleaning agent is a mixture of petroleum ether and butyl acetate, with a mass ratio of petroleum ether to butyl acetate of 3:1. 182L of saturated silica sand used for decolorization in step 4 is soaked in 546L of the cleaning agent for 90 minutes to obtain 728L of a mixture of saturated cleaning agent and recycled silica sand. Step 52: Separate and recover 550L of saturated cleaning agent using a vacuum system. The vacuum level is -0.7Mpa. 178L of recycled silica gel sand can be reused. Step 53: 550L of saturated cleaning agent is filtered through a membrane to obtain residue and regenerated cleaning agent. The residue is recycled and 491L of regenerated cleaning agent is recycled, and the cleaning agent recycling rate reaches 90%.
[0051] Comparative Example 1 Step 1: Flocculation; At room temperature, 1000L of waste engine oil (waste lubricating oil) was added to a reactor, along with 5L of ammonium sulfate and 3L of aluminum sulfate. The stirring device was turned on, and the stirring speed was controlled at 200 rpm. The mixture was then slowly heated to 85℃ and maintained at this temperature for 2 hours. After the reaction was completed, the mixture was transferred to a continuous settling tank, and the settling time was 3 hours. The results showed that the removal rate of mechanical impurities, residual carbon, ash, and moisture reached 79.1%.
[0052] Step 2: Dehydration and dehydrogenation; The flocculated waste engine oil was vacuum filtered at a vacuum degree of -0.08 MPa for 1.5 hours to separate a small amount of water and light components, resulting in dehydrated and dehydrogenated waste engine oil.
[0053] Step 3: Membrane filtration; The feed pressure was controlled at 0.3 MPa, and the dehydrated and dehydrogenated waste engine oil was permeated at a temperature of 60°C to separate 80% of 150SN base oil and 20% concentrate.
[0054] Step 4: Refining and decolorizing; The 150SN base oil after membrane treatment was filtered through silica gel sand at a flow rate of 5L / min to obtain a product with a color of 2.
[0055] Comparative Example 2 Step 1: Flocculation; At room temperature, 1000L of waste engine oil (waste lubricating oil) was added to a reactor, along with 5L of acetic acid and 3L of monoammonium phosphate. The stirring device was turned on, and the stirring speed was controlled at 200 rpm. The mixture was then slowly heated to 85°C and maintained at this temperature for 2 hours. After the reaction was completed, the mixture was transferred to a continuous settling tank, and the settling time was 3 hours. The results showed that the removal rate of mechanical impurities, residual carbon, ash, and moisture reached 81.4%.
[0056] Step 2: Dehydration and dehydrogenation; The flocculated waste engine oil was vacuum filtered at a vacuum degree of -0.08 MPa for 1.5 hours to separate a small amount of water and light components, resulting in dehydrated and dehydrogenated waste engine oil.
[0057] Step 3: Membrane filtration; The feed pressure was controlled at 0.3 MPa, and the dehydrated and dehydrogenated waste engine oil was permeated at a temperature of 60°C to separate 80% of 150SN base oil and 20% concentrate.
[0058] Step 4: Refining and decolorizing; The 150SN base oil after membrane treatment was filtered through silica gel sand at a flow rate of 5L / min to obtain a product with a color of 3.
[0059] Table 1. Comparison of indicators for waste engine oil flocculation treatment in Examples 1, 2, 3 and Comparative Examples 1, 2
[0060] As shown in Table 1, the waste engine oil regeneration process of the present invention has a good recycling effect on spilled oil, tank cleaning oil and waste lubricating oil. The demetallizing agent and flocculant give full play to their respective properties, so that the total removal rate of mechanical impurities, residual carbon, ash and moisture reaches more than 94%.
[0061] Compared with before flocculation, in Example 1, the removal rate of mechanical impurities was 97%, the removal rate of residual carbon was 94%, the removal rate of ash was 98%, the removal rate of moisture was 88%, and the total removal rate was 94.6%. Compared with Example 1, Comparative Example 1, using different flocculants, showed a slightly lower mechanical impurity removal rate of 95.5%, a significantly lower residual carbon removal rate of 76% and a significantly lower ash removal rate of 47%, and a moisture removal rate of 86% within the fluctuation range, with a total removal rate of 76.5%. Comparative Example 2, using different demetallizing agents, showed a significantly lower mechanical impurity removal rate of 84%, a slightly lower residual carbon removal rate of 91.8%, a lower ash removal rate of 92%, and a slightly lower moisture removal rate of 84%. It can be seen that the demetallizing agent of the present invention is much more helpful in reducing the mechanical impurity value compared with other demetallizing agents (acetic acid) in the field, and the flocculant of the present invention is much more helpful in reducing the residual carbon and ash value compared with other flocculants (aluminum sulfate) in the field. When the demetallizing agent and the flocculant of the present invention are added at the same time, the removal rates of mechanical impurities, residual carbon, ash and moisture are further reduced compared with the comparative examples, indicating that the addition of the two has a mutually promoting and synergistic effect. The combined effect of the demetallizing agent and the flocculant in comparative examples 1 and 2 is not as good as the combined effect of ammonium sulfate and monoammonium phosphate in example 1. Furthermore, the color of the regenerated engine oil in comparative examples 1 and 2 cannot meet the qualified product requirement of less than 1.
[0062] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.
Claims
1. A waste engine oil regeneration process, characterized in that, include: Step 1: Flocculation; First, add a demetallizing agent and a flocculant to the waste engine oil at room temperature to obtain a mixture. Then, heat the mixture to the reaction temperature. After the reaction is complete, let the mixture settle to obtain the flocculated waste engine oil. Step 2: Dehydration and dehydrogenation; The flocculated waste oil is then vacuum filtered to obtain dehydrated and dehydrogenated waste oil. Step 3: Membrane filtration; Waste engine oil that has been dehydrated and dehydrogenated is permeated to obtain base oil and concentrate, with the concentrate being used as an asphalt additive product. Step 4: Refining and decolorizing; Regenerated base oil can be obtained by decolorizing the base oil using silica gel sand.
2. The waste engine oil regeneration process as described in claim 1, characterized in that, The volume ratio of waste engine oil to demetallizing agent and flocculant is 1000:8~5:3~1.
3. The waste engine oil regeneration process as described in claim 1, characterized in that, The preferred volume ratio between waste engine oil and demetallizing agent and flocculant is 1000:5:
3.
4. The waste engine oil regeneration process as described in claim 1, characterized in that: The demetallizing agent is at least one of ammonium sulfate, metaphosphoric acid, ammonium thiocarbamate, and dodecylbenzenesulfonic acid. The flocculant is at least one of monoammonium phosphate, acrylamide, polyvinyl alcohol, and polyoxypropylene.
5. The waste engine oil regeneration process as described in claim 1, characterized in that: In step 1: The reaction temperature is 80℃~100℃; The settling time is 2 hours to 5 hours. In step 2: The vacuum degree of vacuum filtration is -0.05 MPa to -0.09 MPa.
6. The waste engine oil regeneration process as described in claim 1, characterized in that: In step 4: the mass ratio of base oil to silica gel sand is 7~5:
1.
7. The waste engine oil regeneration process as described in claim 1, characterized in that, Following step 4, the following is also included: Step 5: Regeneration of silica gel sand; Step 51: Soak the saturated silica sand used for decolorization in Step 4 in a cleaning agent to obtain a mixture of saturated cleaning agent and recycled silica sand; Step 52: Separate the saturated cleaning agent and the recycled silica sand by vacuuming the mixture of saturated cleaning agent and recycled silica sand, and recycle the recycled silica sand. Step 53: The saturated cleaning agent obtained in step 52 is subjected to membrane filtration to obtain residue and regenerated cleaning agent. The residue is recycled and the regenerated cleaning agent is reused.
8. The waste engine oil regeneration process as described in claim 7, characterized in that: The soaking time is 30 min to 100 min; The vacuum level of the vacuum pump is -0.6 MPa to -0.7 MPa.
9. The waste engine oil regeneration process as described in claim 7, characterized in that, The mass ratio of the cleaning agent to the saturated silica gel sand is 6~3:
1.
10. The waste engine oil regeneration process as described in claim 7, characterized in that, The cleaning agent is petroleum ether and butyl acetate, with a mass ratio of petroleum ether to butyl acetate of 6~4:2~1.