Process for regenerating base oil from waste lubricating oil

Abstract

The invention provides a process for regenerating base oil from waste lubricating oil, and belongs to the technical field of base oil processing and production. The preparation process comprises the following steps: preparing biomass activated carbon based on peanut shells; preparing modified biomass activated carbon; pretreatment and extraction of waste lubricating oil; and carrying out molecular distillation and adsorption purification on the oil. Through the process steps of pretreatment, reduced pressure distillation, extraction, molecular distillation, adsorption purification and flash evaporation degassing, the base oil can be produced by using most of logarithms of the waste lubricating oil in society, so that the comprehensive utilization of the waste lubricating oil is realized, and the traditional clay refining process is eliminated in the production process; the problem of secondary pollution caused by waste clay generated in regeneration of the waste lubricating oil is thoroughly solved, and hazardous waste pollution is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of base oil processing and production, and in particular to a process for regenerating base oil from waste lubricating oil. Background Art

[0002] With the acceleration of industrialization and the development of the transportation industry, the consumption of lubricating oil has increased year by year. At the same time, the amount of waste lubricating oil has also increased. Waste lubricating oil contains various harmful substances, such as heavy metals, additive residues, etc. If it is discharged directly without treatment, it will cause serious pollution to the environment. Therefore, effective recycling of waste lubricating oil can not only reduce environmental pollution, but also realize the recycling of resources.

[0003] Existing waste oil regeneration processes include:

[0004] Flocculation-sedimentation-dehydration and slag removal method. This process uses simple physical methods for treatment. It is only for some high-quality oil products. The waste oil is first settled to separate water and other heavy components, and then directly pickled in the subsequent process and adsorbed by white clay, which saves heat energy. The process is also relatively simple, but the pickling sedimentation is slow and takes a long time. It also contains a certain amount of acid slag, which pollutes the environment. The quality of the produced oil is unstable and poor, and does not meet the requirements.

[0005] The high-temperature contact acid-free regeneration process of kaolin has good regenerated oil quality. However, since this process is essentially an improved process of the distillation-kaolin refining process, there are factors such as large kaolin usage >10%, low lubricating oil base oil yield generally <80%, severe equipment corrosion, possible blockage of furnace tubes, and harsh operating conditions. Therefore, it is not suitable for comprehensive promotion of this process in my country.

[0006] Therefore, we propose a process for regenerating base oil from waste lubricating oil, which can improve the efficiency of regenerating base oil from waste lubricating oil and enhance the quality of regenerated base oil. Summary of the invention

[0007] In view of the shortcomings of the prior art, the object of the present invention is to provide a process for regenerating base oil from waste lubricating oil.

[0008] A process for regenerating base oil from waste lubricating oil comprises the following steps:

[0009] S1: Preparation of biomass activated carbon based on peanut shells

[0010] Biomass activated carbon is prepared using peanut shells;

[0011] S2: Preparation of modified biomass activated carbon

[0012] Firstly, biomass activated carbon is modified to obtain thiol-modified biomass activated carbon, and then manganese dioxide is doped with chitosan for encapsulation modification to obtain modified biomass activated carbon;

[0013] S3: Pretreatment and extraction of waste lubricating oil

[0014] The waste lubricating oil is subjected to sedimentation centrifugation to obtain pretreated oil, the pretreated oil is subjected to reduced pressure distillation to separate distillate oil and residue, and the distillate oil is extracted to obtain extracted oil;

[0015] S4: Molecular distillation and adsorption purification of oil

[0016] The extracted oil is subjected to three-stage molecular short-range distillation to obtain base oils of different viscosities, and the base oils of different viscosities are subjected to adsorption purification and flash degassing and dehydration treatment to obtain finished base oils.

[0017] Furthermore, step S1 is to prepare biomass activated carbon based on peanut shells, which specifically includes the following steps:

[0018] S1.1: Dry the peanut shells in a vacuum drying oven at 100-110°C for 24-25 hours, then crush and sieve to obtain the sieve residue, then place the sieve residue in a 1-2 mol / L sodium chloride solution and stir at room temperature for 4-5 hours, with a solid-liquid ratio of 1:2-3, then wash with deionized water 2-3 times and soak for 24-25 hours, and dry in a vacuum drying oven at 65-70°C to obtain the pretreated peanut shell powder;

[0019] S1.2: 8-10 parts by weight of pretreated peanut shell powder are added to 45-60 parts by weight of deionized water, mixed and placed in a high-pressure hydrothermal reactor, reacted at 180-190° C. for 12-14 hours, the reactant is cooled, filtered, washed to neutrality, and then dried to obtain peanut shell-based hydrothermal carbon char;

[0020] S1.3: Place 8-10 parts by weight of peanut shell-based hydrothermal carbon char into 16-20 parts by weight of 2-3 mol / L potassium carbonate solution, stir and mix at room temperature for 2-3 hours, vacuum dry the mixture and place it in a tubular furnace, keep it warm at 700-720°C for 1-2 hours in a nitrogen atmosphere, cool it, wash it to neutrality and then dry it, place it in a nitrogen and oxygen mixed gas after drying, keep it warm at 420-450°C for 1-2 hours to obtain biomass activated carbon.

[0021] Furthermore, step S2 of preparing modified biomass activated carbon specifically comprises the following steps:

[0022] S2.1: 1-2 parts by weight of biomass activated carbon, 3-5 parts by weight of L-cysteine, 0.2-0.3 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 0.1-0.2 parts by weight of N-hydroxysuccinimide are mixed, and the mixed system is placed at 65-70° C. and shaken for reaction for 2-3 hours to obtain thiol-modified biomass activated carbon;

[0023] S2.2: Dissolve 1-2 parts by weight of chitosan in 30-40 parts by weight of 5% glacial acetic acid solution by ultrasonic method, then add 20-30 parts by weight of thiol-modified biomass activated carbon and ultrasonically disperse for 10-12 minutes, then add 4-5 parts by weight of manganese dioxide and ultrasonically disperse for 10-12 minutes to obtain a mixed solution;

[0024] S2.3: Inject the mixed solution into 100-120 parts by weight of 1-2 mol / L sodium hydroxide solution through a syringe to obtain instantly formed modified biomass activated carbon microspheres, wash the obtained modified biomass activated carbon microspheres with deionized water until neutral, put them into an oven to dry and then crush them to obtain modified biomass activated carbon.

[0025] Furthermore, step S3 of pretreatment and extraction of waste lubricating oil specifically comprises the following steps:

[0026] S3.1: After the waste lubricating oil is settled and centrifuged at 60-70°C, it is heated to 110-120°C for evaporation to obtain pre-treated oil, and the pre-treated oil is pumped into a distillation tower at an absolute pressure of 1.2-1.3 kPa and 230-240°C for primary vacuum distillation to separate the fuel oil, and the material after the primary vacuum distillation is pumped into a distillation tower at an absolute pressure of 0.7-0.8 kPa and 320-330°C for secondary vacuum distillation to separate the distillate oil and the residue;

[0027] S3.2: mixing butanol and pentanol to obtain a mixed alcohol, and mixing the mixed alcohol with N-methylpyrrolidone to obtain an extractant;

[0028] S3.3: The distillate oil drawn out from the secondary vacuum distillation tower is cooled to 100-105°C and then pumped into the packed extraction tower from the lower inlet. The extractant enters the tower from the upper inlet of the packed extraction tower for extraction to obtain extracted oil.

[0029] Furthermore, step S4, molecular distillation and adsorption purification of oil, specifically comprises the following steps:

[0030] S4.1: The extracted oil is subjected to three-stage molecular short-path distillation, wherein the distances between the hot and cold plates of the three-stage molecular short-path distillation are 15-20 mm, 25-30 mm and 35-40 mm, respectively, the temperatures of the hot plates are 180-200°C, 200-220°C and 320-340°C, respectively, the temperatures of the cold plates are 20-25°C, 80-85°C and 100-105°C, and the vacuum degrees are all 40-50 Pa. During the distillation process, the distillates of each stage are collected to obtain base oils of different viscosities;

[0031] S4.2: The base oil is stirred magnetically at 300-310 r / min and constant temperature of 125-130°C for 40-50 min, and then the modified biomass activated carbon is added twice, stirred and mixed, and vacuumed and maintained at a vacuum degree of 0.06-0.08 MPa for 30-60 min. The base oil mixture is filtered to separate the modified biomass activated carbon to obtain a semi-finished base oil product;

[0032] S4.3: The semi-finished base oil is preheated to 110-120℃ through a heat exchanger and enters a flash tower for flash degassing and dehydration treatment under a vacuum degree of 0.06-0.08MPa. The base oil after the flash tower is condensed and filtered to obtain the finished base oil.

[0033] Furthermore, the volume fractions of oxygen and nitrogen in the nitrogen-oxygen mixed gas in step S1.3 are 5% and 95% respectively.

[0034] Furthermore, the butanol and pentanol in step S3.2 are mixed in a mixing ratio of 2:3-4 by weight.

[0035] Furthermore, in step S3.2, the mixed alcohol and N-methylpyrrolidone are mixed in a weight ratio of 4:7-8.

[0036] Furthermore, during extraction in step S3.3, the volume flow rate of the distillate oil and the extractant is controlled to be 1:1.

[0037] Furthermore, in step S4.2, the amount of modified biomass activated carbon added each time is 8-10% of the mass of the base oil.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] 1. The present invention increases the chemical adsorption capacity of activated carbon by thiol treatment. The introduction of L-cysteine ​​makes the surface of activated carbon have thiol groups. These thiol groups can form stable chemical bonds with metal ions, sulfur-containing compounds and the like in waste lubricating oil, thereby enhancing the adsorption selectivity of specific impurities, thereby more effectively removing harmful substances that affect the quality of base oil. The modified biomass activated carbon after multi-step treatment has a rich pore structure. At the same time, after being composite-modified with chitosan, manganese dioxide and other substances, the pores are further enriched and refined, which can provide more adsorption sites for adsorbing impurities in waste lubricating oil, improve the adsorption efficiency of impurities in waste lubricating oil, and significantly improve the purity of regenerated base oil.

[0040] 2. Peanut shells have a certain adsorption capacity because they contain many functional groups such as hydroxyl, amino, and carboxyl groups on their surface. The present invention uses peanut shells as raw materials to prepare activated carbon, thereby realizing the resource utilization of agricultural waste. Peanut shells are a common agricultural waste and are usually treated as garbage, which not only takes up space but also may cause environmental pollution. Converting them into biomass activated carbon for waste lubricating oil regeneration not only reduces waste emissions, but also provides a green and environmentally friendly solution for the treatment of waste lubricating oil. The biomass activated carbon prepared based on peanut shells can effectively adsorb impurities in waste lubricating oil, realize the regeneration of waste lubricating oil, and improve the purity of the regenerated base oil.

[0041] 3. The present invention can utilize the vast majority of waste lubricating oil in the society to produce base oil through the process steps of pretreatment, vacuum distillation, extraction, molecular distillation, adsorption purification and flash degassing, thereby realizing the comprehensive utilization of waste lubricating oil. Fuel oil and residue are separated by vacuum distillation and a short-range distiller, and base oils of three specifications of low, medium and high viscosity are produced according to the composition characteristics of the waste lubricating oil. The base oil fractions in the waste lubricating oil are completely separated according to their quality and value, thereby maximizing economic benefits and greatly improving the yield of the product. The yield of the lubricating oil base oil product can reach more than 90%. The production process abolishes the traditional clay refining process, completely solves the secondary pollution problem caused by the waste clay generated in the regeneration of waste lubricating oil, and reduces hazardous waste pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable those skilled in the relevant art to make and use the present disclosure.

[0043] Figure 1 The present invention is a process flow chart for regenerating base oil from waste lubricating oil. DETAILED DESCRIPTION

[0044] The following is a detailed description of a process for regenerating base oil from waste lubricating oil provided by the present invention in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternatives to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0045] Example 1

[0046] A process for regenerating base oil from waste lubricating oil, such as Figure 1 As shown, the following steps are included:

[0047] S1: Preparation of biomass activated carbon based on peanut shells

[0048] S1.1: The peanut shells were dried in a vacuum drying oven at 100°C for 24 hours, then crushed and sieved to obtain the sieved material, and then the sieved material was placed in a 1 mol / L sodium chloride solution and stirred at room temperature for 4 hours, with a solid-liquid ratio of 1:2, and then washed twice with deionized water and soaked for 24 hours, and dried in a vacuum drying oven at 65°C to obtain the pretreated peanut shell powder;

[0049] S1.2: 8 parts by weight of pretreated peanut shell powder are added to 45 parts by weight of deionized water, mixed and placed in a high-pressure hydrothermal reactor, reacted at 180° C. for 12 hours, the reactant is cooled, filtered, washed to neutrality, and then dried to obtain peanut shell-based hydrothermal carbon char;

[0050] S1.3: 8 parts by weight of peanut shell-based hydrothermal carbon char is placed in 16 parts by weight of 2 mol / L potassium carbonate solution, stirred and mixed at room temperature for 2 hours, the mixture is vacuum dried and placed in a tube furnace, kept at 700°C for 1 hour in a nitrogen atmosphere, cooled, washed to neutrality and then dried, and after drying, placed in a nitrogen and oxygen mixed gas and kept at 420°C for 1 hour to obtain biomass activated carbon;

[0051] The volume fractions of oxygen and nitrogen in the nitrogen-oxygen mixture are 5% and 95% respectively.

[0052] S2: Preparation of modified biomass activated carbon

[0053] S2.1: 1 part by weight of biomass activated carbon, 3 parts by weight of L-cysteine, 0.2 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 0.1 parts by weight of N-hydroxysuccinimide are mixed, and the mixed system is placed at 65° C. and shaken for 2 hours to obtain thiol-modified biomass activated carbon;

[0054] S2.2: 1 part by weight of chitosan was dissolved in 30 parts by weight of 5% glacial acetic acid solution by ultrasonic method, then 20 parts by weight of thiol-modified biomass activated carbon was added and ultrasonically dispersed for 10 minutes, and then 4 parts by weight of manganese dioxide was added and ultrasonically dispersed for 10 minutes to obtain a mixed solution;

[0055] S2.3: injecting the mixed solution into 100 parts by weight of 1 mol / L sodium hydroxide solution through a syringe to obtain instantly formed modified biomass activated carbon microspheres, washing the obtained modified biomass activated carbon microspheres with deionized water until neutral, drying them in an oven, and then crushing them to obtain modified biomass activated carbon;

[0056] S3: Pretreatment and extraction of waste lubricating oil

[0057] S3.1: After the waste lubricating oil is settled and centrifuged at 60°C, it is heated to 110°C for evaporation to obtain pre-treated oil, and the pre-treated oil is pumped into a distillation tower at an absolute pressure of 1.2 kPa and 230°C for primary vacuum distillation to separate the fuel oil, and the material after the primary vacuum distillation is pumped into a distillation tower at an absolute pressure of 0.7 kPa and 320°C for secondary vacuum distillation to separate the distillate oil and the residue;

[0058] S3.2: mixing butanol and pentanol in a ratio of 2:3 by weight to obtain a mixed alcohol, and mixing the mixed alcohol with N-methylpyrrolidone in a ratio of 4:7 by weight to obtain an extractant;

[0059] S3.3: The distillate oil drawn out from the secondary vacuum distillation tower is cooled to 100°C and then pumped into the tower from the lower inlet of the packed extraction tower, and the extractant is fed into the tower from the upper inlet of the packed extraction tower, and the volume flow rate of the distillate oil and the extractant is controlled to be 1:1, to obtain the extracted oil;

[0060] S4: Molecular distillation and adsorption purification of oil

[0061] S4.1: The extracted oil is subjected to three-stage molecular short-path distillation, wherein the distances between the hot and cold plates of the three-stage molecular short-path distillation are 15 mm, 25 mm and 35 mm, respectively, the temperatures of the hot plate are 180°C, 200°C and 320°C, respectively, the temperatures of the cold plate are 20°C, 80°C and 100°C, and the vacuum degree is 40 Pa. During the distillation process, the distillates of each stage are collected to obtain base oils of different viscosities;

[0062] S4.2: The base oil is stirred magnetically at a constant temperature of 125°C for 40 minutes at 300 r / min, and then the modified biomass activated carbon is added twice, with the amount of the modified biomass activated carbon added each time being 8% of the mass of the base oil. The mixture is stirred and evacuated and the vacuum degree is maintained at 0.06 MPa for 30 minutes. The base oil mixture is filtered to separate the modified biomass activated carbon to obtain a semi-finished base oil product;

[0063] S4.3: The semi-finished base oil is preheated to 110°C through a heat exchanger and then enters a flash tower for flash degassing and dehydration treatment under a vacuum degree of 0.06MPa. The base oil after the flash tower is condensed and filtered to obtain the finished base oil.

[0064] Example 2

[0065] A process for regenerating base oil from waste lubricating oil, such as Figure 1 As shown, the following steps are included:

[0066] S1: Preparation of biomass activated carbon based on peanut shells

[0067] S1.1: The peanut shells were dried in a vacuum drying oven at 110°C for 25 hours, then crushed and sieved to obtain the sieved material, and then the sieved material was placed in a 1 mol / L sodium chloride solution and stirred at room temperature for 5 hours, with a solid-liquid ratio of 1:2, and then washed with deionized water for 3 times and soaked for 25 hours, and dried in a vacuum drying oven at 70°C to obtain the pretreated peanut shell powder;

[0068] S1.2: 8 parts by weight of pretreated peanut shell powder are added to 45 parts by weight of deionized water, mixed and placed in a high-pressure hydrothermal reactor, reacted at 190° C. for 14 hours, the reactant is cooled, filtered, washed to neutrality, and then dried to obtain peanut shell-based hydrothermal carbon char;

[0069] S1.3: 8 parts by weight of peanut shell-based hydrothermal carbon char is placed in 16 parts by weight of 2 mol / L potassium carbonate solution, stirred and mixed at room temperature for 3 hours, the mixture is vacuum dried and placed in a tube furnace, kept at 720°C for 2 hours in a nitrogen atmosphere, cooled, washed to neutrality and then dried, and after drying, placed in a nitrogen and oxygen mixed gas and kept at 450°C for 2 hours to obtain biomass activated carbon;

[0070] The volume fractions of oxygen and nitrogen in the nitrogen-oxygen mixture are 5% and 95% respectively.

[0071] S2: Preparation of modified biomass activated carbon

[0072] S2.1: 1 part by weight of biomass activated carbon, 3 parts by weight of L-cysteine, 0.2 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 0.1 parts by weight of N-hydroxysuccinimide are mixed, and the mixed system is placed at 70° C. and shaken for 3 hours to obtain thiol-modified biomass activated carbon;

[0073] S2.2: 1 part by weight of chitosan was dissolved in 30 parts by weight of 5% glacial acetic acid solution by ultrasonic method, then 20 parts by weight of thiol-modified biomass activated carbon was added and ultrasonically dispersed for 12 minutes, and then 4 parts by weight of manganese dioxide was added and ultrasonically dispersed for 12 minutes to obtain a mixed solution;

[0074] S2.3: injecting the mixed solution into 100 parts by weight of 1 mol / L sodium hydroxide solution through a syringe to obtain instantly formed modified biomass activated carbon microspheres, washing the obtained modified biomass activated carbon microspheres with deionized water until neutral, drying them in an oven, and then crushing them to obtain modified biomass activated carbon;

[0075] S3: Pretreatment and extraction of waste lubricating oil

[0076] S3.1: After the waste lubricating oil is settled and centrifuged at 70°C, it is heated to 120°C for evaporation to obtain pre-treated oil, and the pre-treated oil is pumped into a distillation tower at an absolute pressure of 1.3 kPa and 240°C for primary vacuum distillation to separate the fuel oil, and the material after the primary vacuum distillation is pumped into a distillation tower at an absolute pressure of 0.8 kPa and 330°C for secondary vacuum distillation to separate the distillate oil and the residue;

[0077] S3.2: mixing butanol and pentanol in a ratio of 2:3 by weight to obtain a mixed alcohol, and mixing the mixed alcohol with N-methylpyrrolidone in a ratio of 4:7 by weight to obtain an extractant;

[0078] S3.3: The distillate oil drawn out from the secondary vacuum distillation tower is cooled to 105°C and then pumped into the packed extraction tower from the lower inlet. The extractant enters the tower from the upper inlet of the packed extraction tower. The volume flow rate of the distillate oil and the extractant is controlled to be 1:1 to obtain the extracted oil.

[0079] S4: Molecular distillation and adsorption purification of oil

[0080] S4.1: The extracted oil is subjected to three-stage molecular short-path distillation, wherein the distances between the hot and cold plates of the three-stage molecular short-path distillation are 20 mm, 30 mm and 40 mm, respectively, the temperatures of the hot plate are 200°C, 220°C and 340°C, respectively, the temperatures of the cold plate are 25°C, 85°C and 105°C, and the vacuum degree is 50 Pa. During the distillation process, the distillates of each stage are collected to obtain base oils of different viscosities;

[0081] S4.2: The base oil is stirred magnetically at 310 r / min and constant temperature of 130°C for 50 min, and then modified biomass activated carbon is added twice, with the amount of modified biomass activated carbon added each time being 8% of the mass of the base oil, and the mixture is stirred and evacuated and maintained at a vacuum degree of 0.08 MPa for 60 min. The base oil mixture is filtered to separate the modified biomass activated carbon to obtain a semi-finished base oil product;

[0082] S4.3: The semi-finished base oil is preheated to 120°C through a heat exchanger and enters a flash tower for flash degassing and dehydration treatment under a vacuum degree of 0.08MPa. The base oil after the flash tower is condensed and filtered to obtain the finished base oil.

[0083] Example 3

[0084] A process for regenerating base oil from waste lubricating oil, such as Figure 1 As shown, the following steps are included:

[0085] S1: Preparation of biomass activated carbon based on peanut shells

[0086] S1.1: The peanut shells were placed in a vacuum drying oven at 100°C and dried for 24 hours, then crushed and sieved to obtain the sieved material, and then the sieved material was placed in a 2 mol / L sodium chloride solution and stirred at room temperature for 4 hours, with a solid-liquid ratio of 1:3, and then washed twice with deionized water and soaked for 24 hours, and dried in a vacuum drying oven at 65°C to obtain the pretreated peanut shell powder;

[0087] S1.2: 10 parts by weight of pretreated peanut shell powder are added to 60 parts by weight of deionized water, mixed and placed in a high-pressure hydrothermal reactor, reacted at 180° C. for 12 hours, the reactant is cooled, filtered, washed to neutrality, and then dried to obtain peanut shell-based hydrothermal carbon char;

[0088] S1.3: 10 parts by weight of peanut shell-based hydrothermal carbon char is placed in 20 parts by weight of 3 mol / L potassium carbonate solution, stirred and mixed at room temperature for 2 hours, the mixture is vacuum dried and placed in a tubular furnace, kept at 700°C for 1 hour in a nitrogen atmosphere, cooled, washed to neutrality and then dried, and after drying, placed in a nitrogen and oxygen mixed gas and kept at 420°C for 1 hour to obtain biomass activated carbon;

[0089] The volume fractions of oxygen and nitrogen in the nitrogen-oxygen mixture are 5% and 95% respectively.

[0090] S2: Preparation of modified biomass activated carbon

[0091] S2.1: 2 parts by weight of biomass activated carbon, 5 parts by weight of L-cysteine, 0.3 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 0.2 parts by weight of N-hydroxysuccinimide are mixed, and the mixed system is placed at 65° C. and shaken for 2 hours to obtain thiol-modified biomass activated carbon;

[0092] S2.2: 2 parts by weight of chitosan are dissolved in 40 parts by weight of 5% glacial acetic acid solution by ultrasonic method, then 30 parts by weight of thiol-modified biomass activated carbon are added and ultrasonically dispersed for 10 minutes, and then 5 parts by weight of manganese dioxide are added and ultrasonically dispersed for 10 minutes to obtain a mixed solution;

[0093] S2.3: injecting the mixed solution into 120 parts by weight of a 2 mol / L sodium hydroxide solution through a syringe to obtain instantaneously formed modified biomass activated carbon microspheres, washing the obtained modified biomass activated carbon microspheres with deionized water until neutral, drying them in an oven, and then crushing them to obtain modified biomass activated carbon;

[0094] S3: Pretreatment and extraction of waste lubricating oil

[0095] S3.1: After the waste lubricating oil is settled and centrifuged at 60°C, it is heated to 110°C for evaporation to obtain pre-treated oil, and the pre-treated oil is pumped into a distillation tower at an absolute pressure of 1.2 kPa and 230°C for primary vacuum distillation to separate the fuel oil, and the material after the primary vacuum distillation is pumped into a distillation tower at an absolute pressure of 0.7 kPa and 320°C for secondary vacuum distillation to separate the distillate oil and the residue;

[0096] S3.2: mixing butanol and pentanol in a ratio of 2:4 by weight to obtain a mixed alcohol, and mixing the mixed alcohol with N-methylpyrrolidone in a ratio of 4:8 by weight to obtain an extractant;

[0097] S3.3: The distillate oil drawn out from the secondary vacuum distillation tower is cooled to 100°C and then pumped into the tower from the lower inlet of the packed extraction tower, and the extractant is fed into the tower from the upper inlet of the packed extraction tower, and the volume flow rate of the distillate oil and the extractant is controlled to be 1:1, to obtain the extracted oil;

[0098] S4: Molecular distillation and adsorption purification of oil

[0099] S4.1: The extracted oil is subjected to three-stage molecular short-path distillation, wherein the distances between the hot and cold plates of the three-stage molecular short-path distillation are 15 mm, 25 mm and 35 mm, respectively, the temperatures of the hot plate are 180°C, 200°C and 320°C, respectively, the temperatures of the cold plate are 20°C, 80°C and 100°C, and the vacuum degree is 40 Pa. During the distillation process, the distillates of each stage are collected to obtain base oils of different viscosities;

[0100] S4.2: The base oil is stirred magnetically at a constant temperature of 125°C for 40 minutes at 300 r / min, and then the modified biomass activated carbon is added twice, with the amount of the modified biomass activated carbon added each time being 10% of the mass of the base oil. The mixture is stirred and evacuated and the vacuum degree is maintained at 0.06 MPa for 30 minutes. The base oil mixture is filtered to separate the modified biomass activated carbon to obtain a semi-finished base oil product;

[0101] S4.3: The semi-finished base oil is preheated to 110°C through a heat exchanger and then enters a flash tower for flash degassing and dehydration treatment under a vacuum degree of 0.06MPa. The base oil after the flash tower is condensed and filtered to obtain the finished base oil.

[0102] Comparative Example 1

[0103] Compared with Example 1, the difference of Comparative Example 1 is that Comparative Example 1 removes step S2, replaces the modified biomass activated carbon in step S4.2 with an equal mass of biomass activated carbon, and prepares the finished base oil without changing the other steps, which is recorded as Comparative Example 1.

[0104] Comparative Example 2

[0105] Compared with Example 1, the difference of Comparative Example 2 is that Comparative Example 2 removes steps S2.2-2.3, replaces the modified biomass activated carbon in step S4.2 with an equal mass of thiol-modified biomass activated carbon, and prepares the finished base oil without changing the other steps, which is recorded as Comparative Example 2.

[0106] Comparative Example 3

[0107] Compared with Example 1, the difference of Comparative Example 3 is that step S4.2 is removed in Comparative Example 3, the semi-finished base oil in S4.3 is replaced with base oil of different viscosity, and the remaining steps remain unchanged to prepare the finished base oil, which is recorded as Comparative Example 3.

[0108] Comparative Example 4

[0109] Compared with Example 1, the difference of Comparative Example 4 is that the adding of modified biomass activated carbon twice in step S4.2 is modified to adding modified biomass activated carbon, and the remaining steps remain unchanged to prepare the finished base oil, which is recorded as Comparative Example 4.

[0110] The finished base oil prepared in Example 1 was analyzed and measured respectively, and the results are shown in Table 1.

[0111] Table 1. Analysis results of finished base oils prepared in Examples 1-3

[0112]

[0113] From the data in Table 1, it can be seen that the finished base oil produced by the production process of the present invention has the advantages of a wide viscosity range, low chroma, stable kinematic viscosity and viscosity index, high flash point, low pour point, low water content, low carbon residue and high yield, and has higher quality and performance.

[0114] The low viscosity base oil in the finished base oil prepared in the comparative example was analyzed and measured respectively, and the measurement results of the low viscosity base oil in Example 1 were used. The results are shown in Table 2.

[0115] Table 2. Comparative Example Finished Base Oil Analysis Results

[0116] Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Chroma 1 5.3 3.6 7.4 1.6 Water mass fraction% trace 0.02 0.02 0.03 trace Total metal amount mmp 47 252 173 483 82 Carbon residue% 0.024 0.23 0.18 0.42 0.06 Acid value mgKOH / g 0.01 0.05 0.03 0.08 0.01 Sulfur mass fraction % 0.1 0.34 0.17 0.37 0.11 Yield % 34.9 30.9 32.8 28.3 33.6

[0117] It can be seen from the data in Table 2 that the data of the comparative example is worse than that of the embodiment, indicating that the activated carbon prepared with peanut shells as raw materials can effectively adsorb impurities in waste lubricating oil, realize the regeneration of waste lubricating oil, and improve the purity of the regenerated base oil. At the same time, after modification, it can provide more adsorption sites for adsorbing impurities in waste lubricating oil, improve the adsorption efficiency of impurities in waste lubricating oil, and significantly improve the purity of the regenerated base oil. From the data of Comparative Example 4, it can be seen that the adsorption and purification effect of adding modified biomass activity twice is better.

[0118] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A process for regenerating base oil from waste lubricating oil, characterized in that: The steps include: S1: Preparation of biomass activated carbon based on peanut shells Biomass activated carbon is prepared using peanut shells; S2: Preparation of modified biomass activated carbon Firstly, biomass activated carbon is modified to obtain thiol-modified biomass activated carbon, and then manganese dioxide is doped with chitosan for encapsulation modification to obtain modified biomass activated carbon; S3: Pretreatment and extraction of waste lubricating oil The waste lubricating oil is subjected to sedimentation centrifugation to obtain pretreated oil, the pretreated oil is subjected to reduced pressure distillation to separate distillate oil and residue, and the distillate oil is extracted to obtain extracted oil; S4: Molecular distillation and adsorption purification of oil The extracted oil is subjected to three-stage molecular short-range distillation to obtain base oils of different viscosities, and the base oils of different viscosities are subjected to adsorption purification and flash degassing and dehydration treatment to obtain finished base oils.

2. A process for regenerating base oil from waste lubricating oil according to claim 1, characterized in that: Step S1 is to prepare biomass activated carbon based on peanut shells, which specifically includes the following steps: S1.1: Dry the peanut shells in a vacuum drying oven at 100-110°C for 24-25 hours, then crush and sieve to obtain the sieve residue, then place the sieve residue in a 1-2 mol / L sodium chloride solution and stir at room temperature for 4-5 hours, with a solid-liquid ratio of 1:2-3, then wash with deionized water 2-3 times and soak for 24-25 hours, and dry in a vacuum drying oven at 65-70°C to obtain the pretreated peanut shell powder; S1.2: 8-10 parts by weight of pretreated peanut shell powder are added to 45-60 parts by weight of deionized water, mixed and placed in a high-pressure hydrothermal reactor, reacted at 180-190° C. for 12-14 hours, the reactant is cooled, filtered, washed to neutrality, and then dried to obtain peanut shell-based hydrothermal carbon char; S1.3: Place 8-10 parts by weight of peanut shell-based hydrothermal carbon char into 16-20 parts by weight of 2-3 mol / L potassium carbonate solution, stir and mix at room temperature for 2-3 hours, vacuum dry the mixture and place it in a tubular furnace, keep it warm at 700-720°C for 1-2 hours in a nitrogen atmosphere, cool it, wash it to neutrality and then dry it, place it in a nitrogen and oxygen mixed gas after drying, keep it warm at 420-450°C for 1-2 hours to obtain biomass activated carbon.

3. A process for regenerating base oil from waste lubricating oil according to claim 2, characterized in that: Step S2: Preparation of modified biomass activated carbon, specifically comprising the following steps: S2.1: 1-2 parts by weight of biomass activated carbon, 3-5 parts by weight of L-cysteine, 0.2-0.3 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 0.1-0.2 parts by weight of N-hydroxysuccinimide are mixed, and the mixed system is placed at 65-70° C. and shaken for reaction for 2-3 hours to obtain thiol-modified biomass activated carbon; S2.2: Dissolve 1-2 parts by weight of chitosan in 30-40 parts by weight of 5% glacial acetic acid solution by ultrasonic method, then add 20-30 parts by weight of thiol-modified biomass activated carbon and ultrasonically disperse for 10-12 minutes, then add 4-5 parts by weight of manganese dioxide and ultrasonically disperse for 10-12 minutes to obtain a mixed solution; S2.3: Inject the mixed solution into 100-120 parts by weight of 1-2 mol / L sodium hydroxide solution through a syringe to obtain instantly formed modified biomass activated carbon microspheres, wash the obtained modified biomass activated carbon microspheres with deionized water until neutral, put them into an oven to dry and then crush them to obtain modified biomass activated carbon.

4. A process for regenerating base oil from waste lubricating oil according to claim 3, characterized in that: Step S3: pretreatment and extraction of waste lubricating oil, specifically comprising the following steps: S3.1: After the waste lubricating oil is settled and centrifuged at 60-70°C, it is heated to 110-120°C for evaporation to obtain pre-treated oil, and the pre-treated oil is pumped into a distillation tower at an absolute pressure of 1.2-1.3 kPa and 230-240°C for primary vacuum distillation to separate the fuel oil, and the material after the primary vacuum distillation is pumped into a distillation tower at an absolute pressure of 0.7-0.8 kPa and 320-330°C for secondary vacuum distillation to separate the distillate oil and the residue; S3.2: mixing butanol and pentanol to obtain a mixed alcohol, and mixing the mixed alcohol with N-methylpyrrolidone to obtain an extractant; S3.3: The distillate oil drawn out from the secondary vacuum distillation tower is cooled to 100-105°C and then pumped into the packed extraction tower from the lower inlet. The extractant enters the tower from the upper inlet of the packed extraction tower for extraction to obtain extracted oil.

5. A process for regenerating base oil from waste lubricating oil according to claim 4, characterized in that: Step S4: molecular distillation and adsorption purification of oil, specifically including the following steps: S4.1: The extracted oil is subjected to three-stage molecular short-path distillation, wherein the distances between the hot and cold plates of the three-stage molecular short-path distillation are 15-20 mm, 25-30 mm and 35-40 mm, respectively, the temperatures of the hot plates are 180-200°C, 200-220°C and 320-340°C, respectively, the temperatures of the cold plates are 20-25°C, 80-85°C and 100-105°C, and the vacuum degrees are all 40-50 Pa. During the distillation process, the distillates of each stage are collected to obtain base oils of different viscosities; S4.2: The base oil is stirred magnetically at 300-310 r / min and constant temperature of 125-130°C for 40-50 min, and then the modified biomass activated carbon is added twice, stirred and mixed, and vacuumed and maintained at a vacuum degree of 0.06-0.08 MPa for 30-60 min. The base oil mixture is filtered to separate the modified biomass activated carbon to obtain a semi-finished base oil product; S4.3: The semi-finished base oil is preheated to 110-120℃ through a heat exchanger and enters a flash tower for flash degassing and dehydration treatment under a vacuum degree of 0.06-0.08MPa. The base oil after the flash tower is condensed and filtered to obtain the finished base oil.

6. A process for regenerating base oil from waste lubricating oil according to claim 2, characterized in that: The volume fractions of oxygen and nitrogen in the nitrogen-oxygen mixed gas in step S1.3 are 5% and 95% respectively.

7. A process for regenerating base oil from waste lubricating oil according to claim 4, characterized in that: In step S3.2, butanol and pentanol are mixed in a mixing ratio of 2:3-4 by weight.

8. The process for regenerating base oil from waste lubricating oil according to claim 4, characterized in that: In step S3.2, the mixed alcohol and N-methylpyrrolidone are mixed in a weight ratio of 4:7-8.

9. A process for regenerating base oil from waste lubricating oil according to claim 4, characterized in that: During extraction in step S3.3, the volume flow rate of the distillate oil and the extractant is controlled to be 1:

1.

10. The process for regenerating base oil from waste lubricating oil according to claim 5, characterized in that: In step S4.2, the amount of modified biomass activated carbon added each time is 8-10% of the mass of the base oil.

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