A non-hydrogenated, clean method for the resource recycling of waste lubricating oil

Abstract

The present invention belongs to the technical field of resource recycling and utilization of waste lubricating oil, and specifically relates to a non-hydrogenation clean waste lubricating oil resource recycling method, comprising the following steps: distilling and pre-oxidizing the waste lubricating oil, cooling it to a specific temperature, adding a flocculant, and compressing the double electric layer by using electrical neutralization and bridging adsorption to destabilize the colloid particles, colloidal particles collide with each other, condense, and precipitate; when floccules appear in the system, adding an organic porous adsorption material to adsorb non-hydrocarbon compounds containing sulfur, nitrogen, and oxygen as well as colloids and asphaltene in the waste lubricating oil to obtain a liquid-solid mixture; filtering and separating the liquid-solid mixture, liquid-liquid extraction of the filtrate by an organic solvent, and mixing the extract with the condensate evaporated from the distillation to obtain a regenerated base oil. The present invention couples the pre-oxidation, distillation, flocculation, adsorption, filtration, and extraction treatment methods to remove impurities and harmful substances in the waste oil to obtain a regenerated base oil, and the whole process is clean and pollution-free.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste lubricating oil resource recycling and utilization, and in particular relates to a non-hydrogenation clean waste lubricating oil resource recycling method. Background Art

[0002] Lubricating oils lubricate friction pairs, reduce wear and noise, provide cooling and insulation, seal, and provide cleansing and dispersion. They are widely used in internal combustion engines, gearboxes, turbines, compressors, and hydraulic systems. With the rapid development of the automotive industry, annual consumption of internal combustion engine oil, the primary lubricant product, has exceeded 5 million tons. However, approximately 70% to 80% of this total lubricant is discarded each year, unusable due to oxidation, wear, and contamination. These lubricants contain compounds such as metal salts, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. Disposal, landfilling, or incineration of these lubricants causes soil, water, and air pollution, as well as significant energy waste.

[0003] Due to the long-term effects of oxygen-rich, high-temperature, high-pressure, high-shear, and circulating conditions, waste lubricating oil contains a certain amount of metal salts, polycyclic short-chain aromatic hydrocarbons, sulfur-, nitrogen-, and oxygen-containing acids, alkalis, water, and other non-hydrocarbon compounds, as well as colloids, asphaltenes, and other impurities. The presence of impurities, which are non-ideal components of lubricating oil, can cause a decrease in the oil's viscosity index, deterioration in its antioxidant stability, an increase in acid value, increased corrosiveness, and an increase in mechanical impurities, shortening the lubricating oil's service life.

[0004] Impurities in waste lubricating oil primarily consist of perishable components in the base oil and various additives used in the lubricating oil production process, typically less than 15%. Other components retain the physical and chemical properties of the base oil. Removing these undesirable components and recycling and repurposing waste lubricating oil has significant social and economic benefits, including addressing environmental pollution, alleviating oil supply constraints, and improving oil resource utilization.

[0005] Common methods for recycling waste lubricating oil include: pickling, adsorption, hydrotreating, and solvent methods. The product quality obtained by the pickling method is unstable, the yield is low, and a large amount of acid residue, acid-containing wastewater and other excreta are generated during the process, causing serious pollution. The adsorption method has a low yield for regenerating lubricating oil, uses a large amount of organic adsorbent, has high energy consumption, and is prone to adsorbing polar additives in the lubricating oil. The hydrotreating method requires large equipment investment, has high requirements for raw material quality, and the catalyst is difficult to adapt to the quality requirements of different waste lubricating oils, resulting in a short production cycle. The solvent method uses the different solubility characteristics of organic solvents in the base oil components and additives, oxidation products, sludge and other impurities in the waste oil to separate impurities and obtain regenerated oil. It has the characteristics of low energy consumption and less pollution. However, the impurity content of the oil products that have undergone traditional pretreatment before solvent extraction is high, resulting in an unstable yield of regenerated lubricating oil. Summary of the Invention

[0006] In response to the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a non-hydrogenation clean waste lubricating oil resource regeneration method. The present invention combines pre-oxidation, distillation, flocculation, adsorption, filtration and extraction treatment methods to remove a large amount of impurities and harmful substances such as colloids, asphaltenes, acids, soaps, nitrogen compounds, sulfur compounds, etc. in the waste oil. The base oil recovery rate reaches more than 88%, the regeneration quality is good, and it has opened up a new path for the resource regeneration of waste lubricating oil.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: A non-hydrogenation clean waste lubricating oil resource regeneration method comprises the following steps: The waste lubricating oil is subjected to distillation and pre-oxidation treatment, and the distillation and pre-oxidation treatment are carried out simultaneously. The pre-oxidation treatment promotes the complete conversion of colloids and asphaltene in the waste lubricating oil, and the light components in the waste lubricating oil are pre-evaporated through distillation.

[0008] After heat exchange and cooling, flocculants are added and stirred, and the double electric layer is compressed by the effects of electrical neutralization and bridging adsorption, causing the colloidal particles to become unstable, colloidal, coagulate, and precipitate.

[0009] When floccules appear in the system, organic porous adsorption material is added and stirred to adsorb non-hydrocarbon compounds containing sulfur, nitrogen, and oxygen as well as colloids and asphaltene in the waste lubricating oil, thereby achieving heterogeneity of the system and obtaining a liquid-solid mixture.

[0010] The liquid-solid mixture is filtered and separated, and the filtrate after filtration and separation is subjected to liquid-liquid extraction with an organic solvent. Non-ideal components are removed by using the principle of like dissolves like, and the filtrate is mixed with the condensate evaporated from distillation to obtain regenerated base oil.

[0011] The present invention firstly performs distillation and pre-oxidation treatment on the waste lubricating oil, and the distillation and pre-oxidation treatment are carried out simultaneously. The pre-oxidation treatment promotes the complete conversion of colloid and asphaltene in the waste lubricating oil, and the light components in the waste lubricating oil are pre-distilled by distillation. Then, a flocculant is added, and the cations in the flocculant, such as Al 3+ Mg 2+ 、Fe 3+The negative charges of heteroatoms such as S, N, and O contained on the surface of colloidal particles and suspended matter in the waste lubricating oil are electrically neutralized, reducing the Zeta potential of the colloidal structure. The colloidal particles change from repulsion to attraction, thereby destroying the stability of the micelles and making it easy for the colloidal particles to collide with each other, aggregate, and separate into phases, forming flocculent coagulation precipitation to achieve preliminary purification. When floccules appear in the system, organic porous adsorption materials are added and stirred to adsorb non-hydrocarbon compounds containing sulfur, nitrogen, and oxygen, as well as colloids and asphaltene in the waste lubricating oil, thereby achieving heterogeneity of the system and obtaining a liquid-solid mixture. The liquid-solid mixture is filtered and separated, and the filtrate after filtration and separation is subjected to liquid-liquid extraction with an organic solvent. The non-ideal components therein are removed by using the principle of like dissolves like, and the residue is mixed with the condensate evaporated from the distillation to obtain the regenerated base oil. The present invention combines pre-oxidation, distillation, flocculation, adsorption, filtration and extraction treatment methods to remove existing and potential impurities and harmful substances such as colloids, asphaltenes, acids, soaps, nitrogen compounds, sulfur compounds, etc. in the waste oil. The base oil recovery rate reaches more than 88%. The whole process is clean and pollution-free, and the regeneration quality is good, opening up a new way for the resource regeneration of waste lubricating oil.

[0012] The non-condensable gas and light fractions in the waste oil are removed by distillation, and the unstable components in the waste lubricating oil are fully reacted under high temperature and air conditions, so that most additives and oxidation products are enriched.

[0013] When the hot waste lubricating oil is cooled to 120℃ through heat exchange, one or more sulfates, nitrates, and chlorides of aluminum, magnesium, zinc, iron, and copper are added to compress the double layer by utilizing electrical neutralization and bridging adsorption, causing the colloidal particles to become unstable, colloidal, condense, and precipitate.

[0014] When a large amount of floccules appear in the system, organic porous adsorption materials are added to utilize their rich pore structure, high specific surface area and groups with excellent adsorption performance to effectively adsorb non-hydrocarbon compounds containing sulfur, nitrogen and oxygen, as well as colloids and asphaltene in the waste lubricating oil.

[0015] The clear liquid after filtration and separation still contains a small amount of impurities such as polycyclic short side chain aromatic hydrocarbons. By adding weak polar solvents such as furfural with similar polarity to the impurities and utilizing the principle of like dissolves like, non-ideal components such as heterocyclic compounds, acidic oxidation products and polycyclic short side chain aromatic hydrocarbons in the waste lubricating oil can be further removed.

[0016] The oil sample separated by filtration is a light yellow clear liquid, which basically meets the quality standards of R-100SH~R-200SH base lubricants in Group I base oils. After being extracted with furfural or N-methylpyrrolidone to remove impurities such as polycyclic short side chain impurities, the oil sample is a light yellow clear transparent liquid.

[0017] In a preferred embodiment of the present invention, the specific steps of distillation and pre-oxidation treatment are as follows: heating the waste lubricating oil to 300°C to 320°C, causing gaseous phase to escape, then heating to 345°C to 360°C, stopping the escape, then heating to 390°C at a rate of 15°C / 10min to 20°C / 10min, causing light fractions to escape, continuing heating to 410°C to 420°C, stopping the escape, maintaining the temperature at 410°C to 420°C and continuously stirring for 15min to 20min. The distillation temperature range of the light fraction is 350°C to 420°C, the color is extremely light, the density is between 0.85 and 0.86, the sulfur content is close to zero, the viscosity index is qualified, and the relevant standards for lubricating oil base oil are met. The light fraction is directly mixed with the raffinate phase to form the lubricating oil base oil, reducing the feed amount of the extraction process without affecting the quality of the base oil, thereby reducing the solvent consumption and solvent loss in the solvent extraction process and improving the economic efficiency of the extraction process.

[0018] The heating temperature, heating rate and holding time involved in the distillation and pre-oxidation processes of the present invention all have specific requirements. The appropriate heating temperature and heating rate are to maintain a balance between distillation and pre-oxidation. If the heating temperature is too low, when it is less than 350°C, the pre-oxidation rate of colloids and asphaltene pre-bio-metastable substances generated during the use of the lubricating oil is slow, the conversion is incomplete, the subsequent flocculation and adsorption effects are poor, the filtering effect is difficult to play a role, the extraction process agent consumption increases, the regenerated oil quality does not meet the standards, and the fraction below 350°C is too light and does not meet the base oil fraction requirements. If the temperature is too high, when it is greater than 420°C, the undeteriorated ideal components in the lubricating oil undergo condensation reactions, the amount of flocculant and adsorbent used increases, the regenerated oil yield decreases, and the economic benefits of resource utilization decrease. At the same time, the fraction above 420°C is too heavy, has a high density and a low viscosity index, and does not meet the base oil quality requirements.

[0019] The ideal fraction in the rapidly heated mixture is not effectively evaporated, and the pre-oxidation is insufficient. The evaporated components contain impurities and have a heavy color, which does not meet the base oil fraction requirements; slow heating leads to a smaller selectivity difference between the pre-oxidation reaction and the side reaction of the ideal component, which is not conducive to the effective pre-oxidation reaction. The appropriate heating rate should be maintained to achieve a balance between distillation and pre-oxidation.

[0020] The ideal fraction in the rapidly heated mixture is not effectively evaporated, and the pre-oxidation is insufficient. The evaporated components contain impurities and have a heavy color, which does not meet the base oil fraction requirements; slow heating leads to a smaller selectivity difference between the pre-oxidation reaction and the side reaction of the ideal component, which is not conducive to the effective pre-oxidation reaction. The appropriate heating rate should be maintained to achieve a balance between distillation and pre-oxidation.

[0021] Proper holding time is essential for promoting the complete pre-oxidation reaction. Suitable heating temperature, appropriate heating rate, and appropriate holding time enable efficient distillation and pre-oxidation, maintaining a balance between oxidation and distillation. This provides a good foundation for subsequent flocculation, adsorption, filtration, and extraction, and also allows for direct mixing of the distillate with the raffinate.

[0022] In a preferred embodiment of the present invention, the flocculant is one or more of sulfates, nitrates or chlorides of aluminum, magnesium, zinc, iron or copper.

[0023] In a preferred embodiment of the present invention, the mass percentage of flocculant is 3% to 8%. The amount of flocculant added directly affects the quality and yield of the regenerated oil, and thus the economic benefits of the resource-based regeneration process. Insufficient flocculant addition will result in incomplete flocculation of colloids, asphaltenes, organic acids and their salts, lubricant additives, and heteroatom compounds, affecting subsequent adsorption. Too little adsorbent will make it difficult to fully adsorb the flocculated substances. Excessively small amounts of flocculant and adsorbent added will result in regenerated oil quality that fails to meet requirements. Increasing the amount of flocculant and adsorbent has limited effect on the performance of the regenerated oil and may increase over-adsorption of the regenerated oil, reduce the regenerated oil yield, increase additive costs, and reduce the benefits of resource utilization.

[0024] In a preferred embodiment of the present invention, after adding the flocculant, the temperature is 110° C. to 120° C., the stirring time is 40 min to 50 min, and the stirring speed is 20 r / min to 40 r / min.

[0025] In a preferred embodiment of the present invention, the organic porous adsorption material is one or more of activated carbon, modified activated clay, and modified bentonite.

[0026] In a preferred embodiment of the present invention, the mass percentage of the organic porous adsorption material is 1% to 3%.

[0027] In a preferred embodiment of the present invention, after the organic porous adsorption material is added, the temperature is 90° C. to 105° C., the stirring time is 40 min to 50 min, and the stirring speed is 20 r / min to 40 r / min.

[0028] The stirring time and temperature after adding flocculants and organic porous adsorbents have a great influence on the results of resource recovery and regeneration. The temperature affects the viscosity, density and other properties of different phases in the system, thereby affecting the speed of flocculation and adsorption, and thus affecting the regeneration effect. Properly increasing the temperature and reducing the viscosity are conducive to the combination of flocculants with colloids, asphaltene, organic acids and their salts, lubricant additives and heteroatom compounds. Too high a temperature may cause the flocculant to fail and reduce the flocculation ability; too low a temperature and too high a viscosity will weaken the Brownian motion, reduce the chance of collision between particles, and be detrimental to the destabilization and coagulation of colloidal particles. If the stirring time is too short, the flocculant and waste lubricating oil are not fully mixed, resulting in poor flocculation effect. If the stirring time is too long, the flocculation agglomeration has reached equilibrium, and the implementation is of little significance.

[0029] Furthermore, after adding the organic porous adsorbent, increasing the temperature is detrimental to adsorption; while lower temperatures are beneficial for adsorption, excessively low temperatures may reduce the adsorption rate. Slow stirring speeds result in uneven concentration distribution, making it prone to excessive localized aggregation. Fast stirring speeds result in uniform concentration distribution, but may disrupt aggregation and adsorption, hindering phase separation.

[0030] In a preferred embodiment of the present invention, the organic solvent is furfural or N-methylpyrrolidone.

[0031] In a preferred embodiment of the present invention, when the organic solvent is furfural, the volume ratio of furfural to waste lubricating oil is 1.2-1.5; when the organic solvent is N-methylpyrrolidone, the volume ratio of N-methylpyrrolidone to waste lubricating oil is 0.9-1.2.

[0032] The non-ideal components mentioned in the present invention refer to impurities such as a certain amount of metal salts, polycyclic short side chain aromatic hydrocarbons, sulfur-, nitrogen-, oxygen-containing acids, alkalis, water, and other non-hydrocarbon compounds and colloids, asphaltene, etc. contained in the waste lubricating oil.

[0033] Compared with the prior art, the present invention has the following significant effects: 1. The present invention first distills and pre-oxidizes the waste lubricating oil. The distillation and pre-oxidation treatments are carried out simultaneously. The pre-oxidation treatment promotes the complete conversion of colloids and asphaltene in the waste lubricating oil. The light components in the waste lubricating oil are pre-distilled by distillation. Then, a flocculant is added. The cations in the flocculant, such as Al 3+ Mg 2+ 、Fe 3+The negative charge of heteroatoms such as S, N, and O contained on the surface of colloidal particles and suspended matter in the waste lubricating oil is neutralized, the Zeta potential of the colloidal structure is reduced, and the colloidal particles change from the original repulsion to attraction, thereby destroying the stability of the micelles, making the colloidal particles more likely to collide with each other, aggregate, and separate into phases, forming flocculent coagulation precipitation, and achieving preliminary purification. When floccules appear in the system, organic porous adsorption materials are added and stirred to adsorb non-hydrocarbon compounds containing sulfur, nitrogen, and oxygen, as well as colloids and asphaltene in the waste lubricating oil, thereby achieving heterogeneity of the system and obtaining a liquid-solid mixture. Finally, the The liquid-solid mixture is filtered and separated, and the filtrate after filtration and separation is subjected to liquid-liquid extraction with an organic solvent. The non-ideal components are removed by using the principle of like dissolves like. The residue is mixed with the light component, that is, the condensate evaporated from the distillation to obtain the regenerated base oil. The present invention combines pre-oxidation, distillation, flocculation, adsorption, filtration and extraction treatment methods to remove existing and potential colloids, asphaltenes, acids, soaps, nitrogen compounds, sulfur compounds and other impurities and harmful substances in the waste oil. The base oil recovery rate reaches more than 88%. The whole process is clean and pollution-free, and the regeneration quality is good, opening up a new way for the resource regeneration of waste lubricating oil.

[0034] 2. The present invention promotes the complete conversion of pre-biological and metastable substances of colloids and asphaltenes produced during the use of lubricating oil under high temperature, high shear, high humidity and strong oxidizing conditions through pre-oxidation treatment, thereby improving the effects of flocculation and adsorption. Distillation and pre-oxidation are carried out simultaneously to pre-evaporate the light components in the waste lubricating oil to reduce losses in subsequent flocculation, adsorption and filtration. Different flocculants are used to achieve flocculation and adsorption of colloids, asphaltenes and lubricating oil additives, thereby achieving heterogeneity of the system and facilitating separation. Non-ideal components are separated by filtration to achieve resource regeneration of the lubricating oil, and extraction further improves the quality of the regenerated lubricating oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The figure is a schematic diagram of the process flow of the non-hydrogenation clean waste lubricating oil resource regeneration method of the present invention. DETAILED DESCRIPTION

[0036] The following is a detailed description of the technical solutions in the embodiments of the present invention, using preferred embodiments and accompanying drawings in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] It should be noted that all professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0038] The present invention is based on the problems of serious pollution, unstable product quality and low yield in the existing methods for resource regeneration of waste lubricating oil. A non-hydrogenation clean waste lubricating oil resource regeneration method is proposed, which comprises the following steps: distilling and pre-oxidizing the waste lubricating oil, heating the waste lubricating oil to 350°C at different speeds, allowing non-condensable gas to escape in the form of gas phase, then heating to 420°C at a speed of 20°C / 10min, keeping warm and continuously stirring for 20min, distilling and pre-oxidizing simultaneously, promoting the complete conversion of colloid and asphaltene in the waste lubricating oil through pre-oxidation, and pre-evaporating the light fraction in the waste lubricating oil through distillation; after heat exchange cooling, adding a flocculant and stirring at 110°C~120°C for 40min ~50min, utilize electrical neutralization and bridging adsorption to compress the double electric layer, making the colloidal particles unstable, colliding with each other, agglomerating and precipitating; when floccules appear in the system, add organic porous adsorption material and stir at 95℃~105℃ for 40min~50min to adsorb non-hydrocarbon compounds containing sulfur, nitrogen and oxygen as well as colloidal and asphaltene in the waste lubricating oil, realize heterogeneity of the system and obtain a liquid-solid mixture; filter and separate the liquid-solid mixture, extract the filtrate after filtration and separation with an organic solvent furfural or NMP, and use the principle of like dissolves like to remove non-ideal components, mix the raffinate phase with the distilled condensate to obtain regenerated base oil, and regenerate the extract phase through solvent regeneration to remove non-ideal components, which can be recycled. The process flow is as follows: Figure 1 shown.

[0039] Example 1 A non-hydrogenation clean waste lubricating oil resource regeneration method comprises the following steps: (1) Add 100g of lubricating oil into an open container equipped with a steam condensation recovery device, and heat it rapidly to 320℃ at 30℃ / 10min. 1.5g of non-condensable gas escapes in the gas phase. The escape ends at 350℃. Continue heating at 18℃ / 10min to 390℃, and light fraction escapes. At 420℃, 7g of light fraction escapes in the gas phase, and the remaining 91.5g is maintained at 420℃. Keep warm for 20min and keep stirring.

[0040] (2) After cooling to 120°C, add 5g of a mixture of aluminum chloride and magnesium sulfate, with the mass of aluminum chloride and magnesium sulfate in the mixture being 2.5g each, and stir at 120°C for 40min at a stirring speed of 30r / min. After adding the flocculant, an asphalt-like black substance appears, which is mainly composed of colloids, asphaltene, organic acids and their salts, lubricating oil additives, and flocculants of heteroatom compounds.

[0041] (3) When a large amount of floccules appear in the above system, add 1.5 g of organic porous adsorbent activated carbon and stir at 100 ° C for 50 min at a stirring speed of 20 r / min to obtain liquid-solid turbidity. Add organic porous adsorption material to turn the floccules appearing in step (2) into fine sand to facilitate subsequent separation.

[0042] (4) The liquid-solid turbid liquid was sent to a plate and frame filter for separation to obtain 82.5 g of clear light yellow filtrate and 15.5 g of filter cake, wherein the clear light yellow filtrate was regenerated oil, and the main components of the filter cake were flocculant, organic porous adsorbent and non-ideal components of lubricating oil, including metal salts, polycyclic short side chain aromatic hydrocarbons, sulfur-, nitrogen-, oxygen-containing acids, alkalis, water and other non-hydrocarbon compounds and colloids, asphaltene and other impurities. This filtrate basically met the quality standards of R-100SH~R-200SH base oils in Class I base oils.

[0043] (5) 82.5 g of the filtrate was extracted with furfural at a volume ratio of 1.5 to oil, to obtain about 99% of the raffinate, i.e., 81.7 g of regenerated oil, which was mixed with 7 g of the light components escaped and condensed during the distillation process of step (1) to obtain the base oil for the entire resource recovery, totaling 88.7 g.

[0044] Example 2 A non-hydrogenation clean waste lubricating oil resource regeneration method comprises the following steps: (1) Add 100g of lubricating oil into an open container equipped with a steam condensation recovery device, and heat it rapidly to 320℃ at a rate of 30℃ / 10min. 1.5g of non-condensable gas escapes in the form of gas phase, and the escape ends at 350℃. Continue heating to 390℃ at a rate of 20℃ / 10min, and the light fraction escapes. At 420℃, 7g of the light fraction escapes in the form of gas phase, and the remaining 91.5g is maintained at 420℃. Keep warm for 20min and keep stirring.

[0045] (2) After cooling to 120°C, add 4.5g of a mixture of aluminum chloride and magnesium sulfate, where the masses of aluminum chloride and magnesium sulfate are 2g and 2.5g respectively, and stir at 120°C for 40min at a stirring speed of 30r / min. After adding the flocculant, an asphalt-like black substance appears, which is mainly composed of colloids, asphaltene, organic acids and their salts, lubricating oil additives, and flocculants of heteroatom compounds.

[0046] (3) When a large amount of floccules appear in the above system, add 1.5 g of organic porous adsorbent activated carbon and stir for 50 min at 100 °C and a stirring speed of 20 r / min to obtain liquid-solid turbidity. Add organic porous adsorption material to turn the floccules appearing in step (2) into fine sand, which is convenient for subsequent separation.

[0047] (4) The liquid-solid turbid liquid was sent to a plate and frame filter for separation to obtain 82.5 g of clear light yellow filtrate and 15 g of filter cake, wherein the clear light yellow filtrate was regenerated oil, and the main components of the filter cake were flocculant, organic porous adsorbent and non-ideal components of lubricating oil, including metal salts, polycyclic short side chain aromatic hydrocarbons, sulfur-, nitrogen-, oxygen-containing acids, alkalis, water and other non-hydrocarbon compounds and colloids, asphaltene and other impurities. This filtrate basically met the quality standards of R-100SH~R-200SH base oils in Class I base oils.

[0048] (5) 82.5 g of the filtrate was extracted with N-methylpyrrolidone at a volume ratio of 1.1 to oil, and about 99% of a clear, transparent light yellow oil sample, i.e., 81.7 g of regenerated oil, was obtained. This was mixed with 7 g of light components that escaped and condensed during the distillation process of step (1) to obtain the base oil for the entire resource recovery, totaling 88.7 g.

[0049] Example 3 A non-hydrogenation clean waste lubricating oil resource regeneration method comprises the following steps: (1) Add 100g of lubricating oil to an open container equipped with a steam condensation recovery device, and quickly heat it to 300℃ at 30℃ / 10min. 1.5g of non-condensable gas escapes in the gas phase. The escape ends at 350℃. Continue heating at 20℃ / 10min to 390℃, and light fraction escapes. At 420℃, 7g of light fraction escapes in the gas phase, and the remaining 91.5g is maintained at 410℃. Keep warm for 15min and keep stirring.

[0050] (2) After cooling to 110°C, add 3g of a mixture of aluminum chloride and magnesium sulfate, with the mass of aluminum chloride and magnesium sulfate in the mixture being 1.5g each, and stir at 110°C for 40min at a stirring speed of 30r / min. After adding the flocculant, an asphalt-like black substance appears, which is mainly composed of colloids, asphaltene, organic acids and their salts, lubricating oil additives, and flocculants of heteroatom compounds.

[0051] (3) When a large amount of floccules appear in the above system, add 1g of organic porous adsorbent activated carbon and stir at 90°C for 50min at a stirring speed of 20r / min to obtain liquid-solid turbidity. Add organic porous adsorbent to turn the floccules appearing in step (2) into fine sand, which is convenient for subsequent separation.

[0052] (4) The liquid-solid turbid liquid was sent to a plate and frame filter for separation to obtain 82.5 g of clear light yellow filtrate and 13 g of filter cake, wherein the clear light yellow filtrate was regenerated oil, and the main components of the filter cake were flocculant, organic porous adsorbent and non-ideal components of lubricating oil, including metal salts, polycyclic short side chain aromatic hydrocarbons, sulfur-, nitrogen-, oxygen-containing acids, alkalis, water and other non-hydrocarbon compounds and colloids, asphaltene and other impurities. This filtrate basically met the quality standards of R-100SH~R-200SH base oils in Class I base oils.

[0053] (5) 82.5 g of the filtrate was subjected to liquid-liquid extraction with furfural at a furfural-to-oil ratio of 1.5, to obtain a clear, transparent light yellow oil sample of about 98.5%, i.e., 81.2 g of regenerated oil, which was mixed with 7 g of light components escaped and condensed during the distillation process of step (1) to obtain the base oil for the entire resource recovery, totaling 88.2 g.

[0054] Example 4 A non-hydrogenation clean waste lubricating oil resource regeneration method comprises the following steps: (1) Add 100g of lubricating oil to an open container equipped with a steam condensation recovery device, and quickly heat it to 310℃ at 30℃ / 10min. 1.5g of non-condensable gas escapes in the form of gas. The escape ends at 350℃. Continue heating to 390℃ at 20℃ / 10min. Light fraction escapes. At 420℃, 7g of light fraction escapes in the form of gas. The remaining 91.5g is maintained at 415℃. Keep warm for 18min and keep stirring.

[0055] (2) After cooling to 115°C by heat exchange, 8g of a mixture of aluminum chloride and magnesium sulfate was added. The mass of aluminum chloride and magnesium sulfate in the mixture was 4g each. The mixture was stirred at 115°C for 40min at a stirring speed of 30r / min. After the flocculant was added, an asphalt-like black substance appeared. The substance was mainly composed of colloids, asphaltene, organic acids and their salts, lubricating oil additives, and flocculants of heteroatom compounds.

[0056] (3) When a large amount of floccules appear in the above system, add 3 g of organic porous adsorbent activated carbon and stir at 105 ° C for 50 min at a stirring speed of 20 r / min to obtain liquid-solid turbidity. Add organic porous adsorption material to turn the floccules appearing in step (2) into fine sand to facilitate subsequent separation.

[0057] (4) The liquid-solid turbid liquid is sent to a panel filter for separation to obtain 82.3 g of clear light yellow filtrate and 20.2 g of filter cake, wherein the clear light yellow filtrate is regenerated oil, and the main components of the filter cake are flocculant, organic porous adsorbent and non-ideal components of lubricating oil, which include metal salts, polycyclic short side chain aromatic hydrocarbons, sulfur, nitrogen, oxygen-containing acids, alkalis, water and other non-hydrocarbon compounds and colloids, asphaltene and other impurities. This filtrate basically meets the quality standards of R-100SH~R-200SH base oils in Class I base oils.

[0058] (5) The filtrate is subjected to liquid-liquid extraction with furfural at a furfural-to-oil ratio of 1.5, and a clear, transparent light yellow oil sample of about 99% is obtained, i.e., 81.5 g of regenerated oil, which is mixed with 7 g of light components escaped and condensed during the distillation process of step (1) to obtain the base oil for the entire resource recovery, totaling 88.5 g.

[0059] Comparative Example 1 A non-hydrogenation clean waste lubricating oil resource regeneration method comprises the following steps: (1) Add 5 g of a mixture of aluminum chloride and magnesium sulfate to 100 g of lubricating oil and stir for 40 min at a stirring speed of 30 r / min.

[0060] (2) Rapidly heat to 320℃ at 30℃ / 10min, 2g of gas phase escapes, and the escape ends at 350℃. Continue heating to 390℃ at 20℃ / 10min, and light fraction escapes. At 420℃, 5g of gas phase escapes, and the remaining 98g is maintained at 420℃. Keep warm for 20min and keep stirring.

[0061] (3) Cool the mixture to 120°C by heat exchange, then add 1.5 g of organic porous adsorbent activated carbon and stir for 50 min at a stirring speed of 20 r / min to obtain a liquid-solid turbidity.

[0062] (4) The liquid-solid turbid liquid is sent to a plate and frame filter for filtration and separation.

[0063] (5) The filtrate is subjected to liquid-liquid extraction with furfural, with a volume ratio of furfural to oil of 1.5.

[0064] In Comparative Example 1, since the flocculant is added first and then distillation and pre-oxidation are carried out, the pre-biological-metastable substances of the colloid and asphalt are not effectively converted and are difficult to aggregate, the flocculation and adsorption effects are difficult to fully exert, the filtration process is extremely poor, impurities and non-ideal substances are difficult to separate, and the product quality is difficult to meet the requirements of resource recycling.

[0065] Comparative Example 2 A non-hydrogenation clean waste lubricating oil resource regeneration method comprises the following steps: (1) Add 5 g of a mixture of aluminum chloride and magnesium sulfate to 100 g of lubricating oil and stir for 40 min at a stirring speed of 30 r / min.

[0066] (2) When a large amount of flocculent material appears in the above system, add 1.5 g of organic porous adsorbent activated carbon and stir for 50 min at a stirring speed of 20 r / min to obtain turbid material.

[0067] (3) The turbid material was added to an open container equipped with a steam condensation recovery device, and rapidly heated to 320°C at a rate of 30°C / 10min. 3g of gas phase escaped, and the escape ended at 350°C. The material was heated continuously at a rate of 20°C / 10min to 390°C, and light fractions escaped. The material was heated to 420°C, and the gas phase escaped. The remaining 99.5g was maintained at 420°C. The temperature was kept at this temperature for 20min, and stirring was continued.

[0068] (4) Send to plate and frame filter for filtration and separation.

[0069] (5) The filtrate is subjected to liquid-liquid extraction with furfural, with a volume ratio of furfural to oil of 1.5.

[0070] In Comparative Example 2, since flocculants and organic porous adsorption substances are added first and then distilled and pre-oxidized, the pre-biological-metastable substances of colloids and asphaltene are not effectively converted and are difficult to aggregate. The flocculation and adsorption effects are almost not exerted, the filtration process is poor, impurities and non-ideal substances are difficult to separate, and the product quality is difficult to meet the requirements of resource recycling.

[0071] Comparative Example 3 A non-hydrogenation clean waste lubricating oil resource regeneration method comprises the following steps: (1) Add 100g of lubricating oil to an open container equipped with a vapor condensation recovery device, and heat it rapidly to 320℃ at a rate of 30℃ / 10min. 1.5g of gas phase will escape. The escape ends at 350℃. Continue heating at a rate of 20℃ / 10min to 390℃. Light fractions will escape. At 420℃, 7g of gas phase will escape. The remaining 91.5g is maintained at 420℃. Keep warm for 20min and keep stirring.

[0072] (2) Send the above substances into a plate and frame filter for filtration and separation.

[0073] (3) Then add 5 g of a mixture of aluminum chloride and magnesium sulfate and stir for 40 minutes at a stirring speed of 30 r / min.

[0074] (4) Add 1.5 g of organic porous adsorbent activated carbon and stir for 50 min at a stirring speed of 20 r / min.

[0075] (5) Then, furfural was used for liquid-liquid extraction with a volume ratio of 1.5 to oil.

[0076] In Comparative Example 3, distillation and pre-oxidation are first performed, followed by filtration, and then flocculation and adsorption. Since the filtration operation is placed before the flocculation and adsorption, floccules and sediments have not yet been formed, and the filtration process is completely ineffective.

[0077] Comparative Example 4 A non-hydrogenation clean waste lubricating oil resource regeneration method comprises the following steps: (1) Add 100g of lubricating oil to an open container equipped with a vapor condensation recovery device, and heat it rapidly to 320℃ at a rate of 30℃ / 10min. 1.5g of gas phase will escape. The escape ends at 350℃. Continue heating at a rate of 20℃ / 10min to 390℃. Light fractions will escape. At 420℃, 7g of gas phase will escape. The remaining 91.5g is maintained at 420℃. Keep warm for 20min and keep stirring.

[0078] (2) Then, furfural was used for liquid-liquid extraction with a volume ratio of 1.5 to oil.

[0079] (3) Cool the mixture to 120°C after heat exchange, add 5g of a mixture of aluminum chloride and magnesium sulfate, and stir for 40 minutes while adding. The stirring speed is 30r / min.

[0080] (4) When a large amount of flocculent material appears in the above system, add 1.5 g of organic porous adsorbent activated carbon and stir for 50 min at a stirring speed of 20 r / min to obtain turbid material.

[0081] (5) The turbid liquid is sent to a plate and frame filter for filtration and separation.

[0082] In Comparative Example 4, the extraction is placed after distillation and pre-oxidation, resulting in extremely high solvent consumption, and the solvent is difficult to have equal and good selectivity for different impurities. The impurity removal rate is difficult to improve, and the product quality is difficult to meet the requirements of resource recycling.

[0083] The resource recycling method disclosed herein is primarily targeted at waste lubricating oil that is regularly replaced according to operating procedures during the processing of mechanical equipment, internal combustion engines, and other processes. Under the long-term effects of oxygen-rich, high-temperature, high-pressure, high-shear, and hot-cold cycling conditions, the additives in the lubricating oil and the active groups in the molecular chain react, resulting in impurities such as sludge, colloids, asphaltenes, additives and their decomposition products, organic acids and their salts, heteroatom compounds such as S, N, O, and Cl, and condensed aromatics in the waste lubricating oil. Compared to unused lubricating oil, the waste lubricating oil is darker in color, appearing dark black or dark yellow. It also has a lower viscosity index, deteriorating antioxidant stability, an increased acid value, stronger corrosiveness, and an increase in mechanical impurities.

[0084] In summary, the present invention first distills and pre-oxidizes the waste lubricating oil, and the distillation and pre-oxidation treatments are carried out simultaneously. The pre-oxidation treatment promotes the complete conversion of colloids and asphaltene in the waste lubricating oil, and the light components in the waste lubricating oil are pre-distilled by distillation. Then, a flocculant is added, and the cations in the flocculant, such as Al 3+ Mg 2+ 、Fe 3+ The negative charge of heteroatoms such as S, N, and O contained on the surface of colloidal particles and suspended matter in waste lubricating oil is neutralized, reducing the Zeta potential of the colloidal structure. The colloidal particles change from repulsion to attraction, thereby destroying the stability of the micelles, causing the colloidal particles to collide with each other, aggregate, and separate into phases, forming flocculent coagulation precipitation to achieve purification. When floccules appear in the system, organic porous adsorption materials are added and stirred to adsorb non-hydrocarbon compounds containing sulfur, nitrogen, and oxygen, as well as colloids and asphaltene in the waste lubricating oil, thereby achieving heterogeneity of the system and obtaining a liquid-solid mixture. The liquid-solid mixture is filtered and separated, and the filtrate after filtration and separation is subjected to liquid-liquid extraction with an organic solvent. Non-ideal components are removed by using the principle of like dissolves like, and the base oil is mixed with the condensate evaporated from the distillation to obtain a regenerated base oil. The present invention combines pre-oxidation, distillation, flocculation, adsorption, filtration, extraction and other treatment methods to remove a large amount of colloids, asphaltenes, acids, soaps, nitrogen compounds, sulfur compounds and other impurities and harmful substances in the waste oil. The base oil recovery rate reaches more than 88%, the regeneration quality is good, and a new way to regenerate waste lubricating oil resources is opened up.

[0085] It should be noted that when numerical ranges are mentioned in the present invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints may be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes preferred embodiments. Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0086] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the present invention and its equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for recycling waste lubricating oil without hydrogenation cleaning, characterized in that: The following steps are involved: The waste lubricating oil is subjected to distillation and pre-oxidation treatment, and the distillation and pre-oxidation treatment are carried out simultaneously. The pre-oxidation treatment promotes the complete conversion of colloid and asphaltene in the waste lubricating oil, and the fraction in the waste lubricating oil is first evaporated by distillation; After heat exchange and cooling, flocculants are added for stirring, and the double electric layer is compressed by the effects of electrical neutralization and bridging adsorption, so that the colloidal particles become unstable, colloidal, colloidal, coagulated, and precipitated. When floccules appear in the system, organic porous adsorbent is added and stirred to adsorb non-hydrocarbon compounds containing sulfur, nitrogen and oxygen as well as colloids and asphaltene in the waste lubricating oil, thereby achieving heterogeneity of the system and obtaining a liquid-solid mixture; The liquid-solid mixture is filtered and separated, and the filtrate after filtration and separation is subjected to liquid-liquid extraction by an organic solvent. Non-ideal components are removed by using the principle of like dissolves like, and the residue is mixed with the condensate evaporated by distillation to obtain a regenerated base oil.

2. The non-hydrogenation clean waste lubricating oil resource regeneration method according to claim 1, characterized in that: The specific steps of distillation and pre-oxidation treatment are: heating the waste lubricating oil to 300℃~320℃, gas phase escape occurs, then heating to 345℃~360℃, the escape ends, then heating to 390℃ at a rate of 15℃ / 10min~20℃ / 10min, the light fraction escapes, continuing to heat to 410℃~420℃, the escape ends, maintaining the temperature at 410℃~420℃ and continuing to keep warm and stir for 15min~20min.

3. The non-hydrogenation clean waste lubricating oil resource regeneration method according to claim 1, characterized in that: The flocculant is one or more of the sulfate, nitrate or chloride of aluminum, magnesium, zinc, iron or copper.

4. The non-hydrogenation clean waste lubricating oil resource regeneration method according to claim 1, characterized in that: The mass percentage of flocculant is 3%~8%.

5. The non-hydrogenation clean waste lubricating oil resource regeneration method according to claim 1, characterized in that: After adding the flocculant, the temperature is 110℃~120℃, the stirring time is 40min~50min, and the stirring speed is 20r / min~40r / min.

6. The non-hydrogenation clean waste lubricating oil resource regeneration method according to claim 1, characterized in that: The organic porous adsorption material is one or more of activated carbon, modified activated clay and modified bentonite.

7. The non-hydrogenation clean waste lubricating oil resource regeneration method according to claim 1, characterized in that: The mass percentage of organic porous adsorption material is 1%~3%.

8. The non-hydrogenation clean waste lubricating oil resource regeneration method according to claim 1, characterized in that: After adding the organic porous adsorption material, the temperature is 90°C~105°C, the stirring time is 4min~50min, and the stirring speed is 20r / min~40r / min.

9. The non-hydrogenation clean waste lubricating oil resource regeneration method according to claim 1, characterized in that: The organic solvent is furfural or N-methylpyrrolidone.

10. The non-hydrogenation clean waste lubricating oil resource regeneration method according to claim 9, characterized in that: When the organic solvent is furfural, the volume ratio of furfural to waste lubricating oil is 1.2-1.5; when the organic solvent is N-methylpyrrolidone, the volume ratio of N-methylpyrrolidone to waste lubricating oil is 0.9-1.2.

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