A process for regenerating base oil from waste lubricating oil

Abstract

The present invention provides a process for regenerating base oil from waste lubricating oil, belonging to the technical field of base oil processing and production; its preparation process includes the following steps: preparing biomass activated carbon based on peanut shells; preparing modified biomass activated carbon; pre-treating and extracting waste lubricating oil; molecular distillation and adsorption purification of oil. Through the technological steps of pre-treatment, vacuum distillation, extraction, molecular distillation, adsorption purification and flash degassing, it is possible to use the vast majority of waste lubricating oil in society to produce base oil, realizing the comprehensive utilization of waste lubricating oil. The traditional clay refining process is abolished in the production process, completely solving the secondary pollution problem caused by waste clay generated in the regeneration of waste lubricating oil and reducing hazardous waste pollution.

Description

Technical Field

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

[0002] With the acceleration of the industrialization process and the development of the transportation industry, the consumption of lubricating oil has increased year by year. At the same time, the generation of waste lubricating oil has also increased. Waste lubricating oil contains various harmful substances, such as heavy metals, additive residues, etc. Therefore, effective recovery and treatment of waste lubricating oil can not only reduce environmental pollution but also realize the recycling of resources.

[0003] The existing waste oil regeneration processes include:

[0004] Flocculation-sedimentation-dehydration and deslagging method. This process uses simple physical methods for treatment and is only applicable to some oils with higher quality. After the waste oil is first sedimented to separate water and other heavy components, it enters the subsequent process for direct pickling and then clay adsorption. This saves heat energy and the process is relatively simple. However, pickling sedimentation is relatively slow, takes a long time, and contains a certain amount of acid slag, which pollutes the environment. The quality of the produced oil is unstable and of poor quality, not meeting the requirements.

[0005] Clay high-temperature contact acid-free regeneration process. The quality of the regenerated oil by this process is good, but since this process is essentially an improved process of the distillation-clay refining process, there are factors such as a large amount of clay usage (>10%), a relatively low yield of lubricating oil base oil (generally <80%), serious equipment corrosion, possible blockage of furnace tubes, and relatively harsh operating conditions. Therefore, it is not suitable to be widely promoted in China.

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

[0007] Aiming at the deficiencies of the existing technology, the purpose 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 includes the following steps:

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

[0010] Prepare biomass activated carbon using peanut shells;

[0011] S2: Preparation of modified biomass activated carbon

[0012] First, modify the biomass activated carbon to obtain thiolated biomass activated carbon, and then wrap and modify it with manganese dioxide-doped chitosan to obtain modified biomass activated carbon;

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

[0014] Perform sedimentation centrifugation on the waste lubricating oil to obtain pretreated oil. Subject the pretreated oil to vacuum distillation to separate the distillate oil and residue. Extract the distillate oil to obtain the extracted oil;

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

[0016] Perform three-stage molecular short-path distillation on the extracted oil to obtain base oils with different viscosities. Subject the base oils with different viscosities to adsorption purification, flash degassing, and dehydration treatment to obtain finished base oils.

[0017] Furthermore, step S1 prepares biomass activated carbon based on peanut shells, specifically including the following steps:

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

[0019] S1.2: Add 8-10 parts by weight of the pretreated peanut shell powder to 45-60 parts by weight of deionized water, mix and place in a high-pressure hydrothermal reaction kettle, and react at 180-190°C for 12-14h. After cooling the reactant, filter and wash it to neutral and then dry to obtain peanut shell-based hydrothermal carbon char;

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

[0021] Furthermore, the preparation of the modified biomass activated carbon in step S2 specifically includes the following steps:

[0022] S2.1: Mix 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. Place the mixed system under the condition of 65 - 70 °C and shake - react for 2 - 3 h to obtain thiolated 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 thiolated biomass activated carbon and ultrasonically disperse for 10 - 12 min, and then add 4 - 5 parts by weight of manganese dioxide and ultrasonically disperse for 10 - 12 min 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 instant - formed modified biomass activated carbon microspheres. Wash the obtained modified biomass activated carbon microspheres with deionized water until neutral, dry them in an oven and then crush them to obtain modified biomass activated carbon.

[0025] Further, the pretreatment and extraction of waste lubricating oil in step S3 specifically include the following steps:

[0026] S3.1: Let the waste lubricating oil settle and be centrifugally separated at 60 - 70 °C, then heat it to 110 - 120 °C for evaporation to obtain pretreated oil. Pump the pretreated oil into a distillation column with an absolute pressure of 1.2 - 1.3 kPa and a temperature of 230 - 240 °C for primary vacuum distillation to separate fuel oil. The material after primary vacuum distillation is pumped into a distillation column with an absolute pressure of 0.7 - 0.8 kPa and a temperature of 320 - 330 °C for secondary vacuum distillation to separate distillate oil and residue;

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

[0028] S3.3: Cool the distillate oil led out from the secondary vacuum distillation column to 100 - 105 °C, then pump it into the tower from the lower inlet of the packed extraction column, and the extractant enters the tower from the upper inlet of the packed extraction column for extraction to obtain the extracted oil.

[0029] Further, the molecular distillation and adsorption purification of oil in step S4 specifically include the following steps:

[0030] S4.1: Subject the extracted oil to three-stage molecular short-path distillation. The distances between the hot and cold plates in the three-stage molecular short-path distillation are 15 - 20 mm, 25 - 30 mm, and 35 - 40 mm in sequence. The hot plate temperatures are 180 - 200 °C, 200 - 220 °C, and 320 - 340 °C in sequence. The cold plate temperatures are 20 - 25 °C, 80 - 85 °C, and 100 - 105 °C. The vacuum degree is 40 - 50 Pa for all. Collect the distillates at each stage during the distillation process to obtain base oils with different viscosities;

[0031] S4.2: Under the condition of 300 - 310 r / min, magnetically stir the base oil at a constant temperature of 125 - 130 °C for 40 - 50 min. Then add the modified biomass activated carbon in two portions and stir to mix. Evacuate and maintain the vacuum degree at 0.06 - 0.08 MPa for 30 - 60 min. Filter and separate the modified biomass activated carbon from the base oil mixture to obtain a semi-finished base oil;

[0032] S4.3: Preheat the semi-finished base oil to 110 - 120 °C through a heat exchanger and then enter a flash distillation tower. Conduct flash degassing and dehydration treatment under the condition of a vacuum degree of 0.06 - 0.08 MPa. After condensation, filter the base oil after the flash distillation tower to obtain the finished base oil.

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

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

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

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

[0037] Furthermore, in step S4.2, the addition amount of the modified biomass activated carbon 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 through mercaptanization treatment. The introduction of L-cysteine makes the surface of activated carbon carry mercapto groups. These mercapto groups can form stable chemical bonds with metal ions, sulfur-containing compounds, etc. in waste lubricating oil, enhancing the adsorption selectivity for specific impurities, thereby more effectively removing harmful substances that affect the quality of base oil. The modified biomass activated carbon treated through multiple steps has a rich pore structure. After being compound-modified with substances such as chitosan and manganese dioxide, 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 increase the purity of the regenerated base oil.

[0040] 2. Peanut shells have a certain adsorption capacity due to the presence of 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, realizing the resource utilization of agricultural waste. Peanut shells are a common agricultural waste, usually treated as garbage, which not only occupies space but may also 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. Through the technological steps of pretreatment, vacuum distillation, extraction, molecular distillation, adsorption purification, and flash degassing, the present invention can use the vast majority of waste lubricating oil in society to produce base oil, realizing the comprehensive utilization of waste lubricating oil. Fuel oil and residue are separated by vacuum distillation and a short-path distiller. According to the compositional characteristics of waste lubricating oil, base oils with three specifications of low, medium, and high viscosities are produced, enabling the complete separation of the base oil fractions in waste lubricating oil according to different qualities and values, achieving the maximization of economic benefits, greatly increasing the product yield. The yield of lubricating oil base oil products can reach more than 90%. The traditional clay refining process is abolished in the production process, completely solving the secondary pollution problem caused by waste clay generated during the regeneration of waste lubricating oil and reducing hazardous waste pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings incorporated herein and constituting a part of the specification illustrate embodiments of the present disclosure and, together with the specification, are further used to explain the principles of the present disclosure and enable those skilled in the relevant art to implement and use the present disclosure.

[0043] Figure 1 It is a process flow diagram for regenerating base oil from waste lubricating oil adopted in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The following will describe in detail 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 should be noted here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments. For some well-known technologies, those skilled in the art can also adopt other alternative methods for implementation; moreover, the accompanying drawings are only for more specifically describing 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, as Figure 1 shown, includes the following steps:

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

[0048] S1.1: Place peanut shells in a vacuum drying oven at 100 °C for 24 h, then crush and sieve them to obtain the undersize material. Then place the undersize material in a 1 mol / L sodium chloride solution and stir at room temperature for 4 h, with a solid-liquid ratio of 1:2. Then wash it twice with deionized water and soak it for 24 h, and dry it in a vacuum drying oven at 65 °C to obtain pretreated peanut shell powder;

[0049] S1.2: Add 8 parts by weight of the pretreated peanut shell powder to 45 parts by weight of deionized water, mix and place it in a high-pressure hydrothermal reaction kettle, react at 180 °C for 12 h, cool the reactant, filter and wash it until neutral, and then dry it to obtain peanut shell-based hydrochar;

[0050] S1.3: Put 8 parts by weight of peanut shell-based hydrochar into 16 parts by weight of a 2 mol / L potassium carbonate solution, stir and mix at room temperature for 2 h, vacuum dry the mixture and then place it in a tubular furnace. Under a nitrogen atmosphere, keep it at 700 °C for 1 h, cool it, wash it until neutral and then dry it. After drying, place it in a nitrogen-oxygen mixed gas and keep it at 420 °C for 1 h to obtain biomass activated carbon;

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

[0052] S2: Preparation of modified biomass activated carbon

[0053] S2.1: Mix 1 part by weight of biomass activated carbon, 3 parts by weight of L-cysteine, 0.2 part by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 0.1 part by weight of N-hydroxysuccinimide. Place the mixed system at 65 °C and react with shaking for 2 h to obtain thiolated biomass activated carbon;

[0054] S2.2: Dissolve 1 part by weight of chitosan in 30 parts by weight of 5% glacial acetic acid solution by ultrasonic method. Then add 20 parts by weight of mercapto-functionalized biomass activated carbon and disperse it ultrasonically for 10 min. Next, add 4 parts by weight of manganese dioxide and disperse it ultrasonically for 10 min to obtain a mixed solution;

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

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

[0057] S3.1: Let the waste lubricating oil settle and be centrifuged at 60 °C, then heat it to 110 °C for evaporation to obtain pretreated oil. Pump the pretreated oil into a distillation column at an absolute pressure of 1.2 kPa and 230 °C for the first-stage vacuum distillation to separate fuel oil. Pump the material after the first-stage vacuum distillation into a distillation column at an absolute pressure of 0.7 kPa and 320 °C for the second-stage vacuum distillation to separate distillate oil and residue;

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

[0059] S3.3: Cool the distillate oil drawn from the second-stage vacuum distillation column to 100 °C, then pump it into the tower from the lower inlet of the packed extraction column. The extractant enters the tower from the upper inlet of the packed extraction column. Control the volume flow rate of the distillate oil and the extractant to be 1:1 to obtain the extracted oil;

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

[0061] S4.1: Perform three-stage molecular short-path distillation on the extracted oil. The distances between the hot and cold plates in the three-stage molecular short-path distillation are 15 mm, 25 mm, and 35 mm in sequence, the hot plate temperatures are 180 °C, 200 °C, and 320 °C in sequence, the cold plate temperatures are 20 °C, 80 °C, and 100 °C, and the vacuum degree is 40 Pa in all cases. Collect the distillates at each stage during the distillation process to obtain base oils with different viscosities;

[0062] S4.2: Under the condition of 300 r / min, keep the temperature at 125 °C and stir magnetically for 40 min for the base oil. Then add the modified biomass activated carbon in two portions. The addition amount of the modified biomass activated carbon each time is 8% of the mass of the base oil. Stir and mix, evacuate and maintain the vacuum degree at 0.06 MPa for 30 min. Filter and separate the modified biomass activated carbon from the base oil mixture to obtain semi-finished base oil;

[0063] S4.3: The semi-finished base oil is preheated to 110 °C by a heat exchanger and enters the flash distillation column, where flash degassing and dehydration are carried out under the condition of a vacuum degree of 0.06 MPa. The base oil after the flash distillation column is condensed and then filtered to obtain the finished base oil.

[0064] Example 2

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

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

[0067] S1.1: Place the peanut shells in a vacuum drying oven at 110 °C for 25 h, then crush and sieve them to obtain the undersize material. Then place the undersize material in a 1 mol / L sodium chloride solution and stir at room temperature for 5 h, with a solid-liquid ratio of 1:2. Then wash it 3 times with deionized water and soak it for 25 h, and dry it in a vacuum drying oven at 70 °C to obtain the pretreated peanut shell powder;

[0068] S1.2: Add 8 parts by weight of the pretreated peanut shell powder to 45 parts by weight of deionized water, mix them and place them in a high-pressure hydrothermal reaction kettle, react at 190 °C for 14 h, cool the reactant, filter and wash it until neutral, and then dry it to obtain peanut shell-based hydrochar;

[0069] S1.3: Put 8 parts by weight of peanut shell-based hydrochar into 16 parts by weight of a 2 mol / L potassium carbonate solution, stir and mix at room temperature for 3 h, vacuum dry the mixture, then place it in a tubular furnace, keep it at 720 °C for 2 h in a nitrogen atmosphere, cool it, wash it until neutral and then dry it. After drying, place it in a nitrogen-oxygen mixed gas and keep it at 450 °C for 2 h to obtain biomass activated carbon;

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

[0071] S2: Preparation of modified biomass activated carbon

[0072] S2.1: Mix 1 part by weight of biomass activated carbon, 3 parts by weight of L-cysteine, 0.2 part by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 0.1 part by weight of N-hydroxysuccinimide, place the mixed system at 70 °C, and shake and react for 3 h to obtain thiolated biomass activated carbon;

[0073] S2.2: Dissolve 1 part by weight of chitosan in 30 parts by weight of a 5% glacial acetic acid solution by ultrasonic method, then add 20 parts by weight of thiolated biomass activated carbon and ultrasonically disperse for 12 min, and then add 4 parts by weight of manganese dioxide and ultrasonically disperse for 12 min to obtain a mixed solution;

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

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

[0076] S3.1: Let the waste lubricating oil settle and be centrifuged at 70 °C, then heat it to 120 °C for evaporation to obtain pretreated oil. Pump the pretreated oil into a distillation column at an absolute pressure of 1.3 kPa and 240 °C for the first-stage vacuum distillation to separate fuel oil. The material after the first-stage vacuum distillation is pumped into a distillation column at an absolute pressure of 0.8 kPa and 330 °C for the second-stage vacuum distillation to separate distillate oil and residue;

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

[0078] S3.3: Cool the distillate oil drawn from the second-stage vacuum distillation column to 105 °C, then pump it into the tower from the lower inlet of the packed extraction column. The extractant enters the tower from the upper inlet of the packed extraction column. Control the volume flow rate of the distillate oil and the extractant to be 1:1 to obtain the extracted oil;

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

[0080] S4.1: Conduct three-stage molecular short-path distillation on the extracted oil. The distances between the hot and cold plates in the three-stage molecular short-path distillation are 20 mm, 30 mm and 40 mm in sequence, the hot plate temperatures are 200 °C, 220 °C and 340 °C in sequence, the cold plate temperatures are 25 °C, 85 °C and 105 °C, and the vacuum degree is 50 Pa for all. Collect the distillates at each stage during the distillation process to obtain base oils with different viscosities;

[0081] S4.2: Under the condition of 310 r / min, magnetically stir the base oil at a constant temperature of 130 °C for 50 min, then add modified biomass activated carbon in two batches. The addition amount of modified biomass activated carbon each time is 8% of the mass of the base oil. Stir and mix, evacuate and maintain the vacuum degree at 0.08 MPa for 60 min. Filter and separate the modified biomass activated carbon from the base oil mixture to obtain semi-finished base oil;

[0082] S4.3: Preheat the semi-finished base oil to 120 °C through a heat exchanger and enter a flash distillation column. Conduct flash degassing and dehydration treatment under the condition of a vacuum degree of 0.08 MPa. The base oil after the flash distillation column is condensed and then filtered to obtain finished base oil.

[0083] Example 3

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

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

[0086] S1.1: Place peanut shells in a vacuum drying oven at 100 °C for 24 h, then crush and sieve them to obtain the undersize fraction. Then place the undersize fraction in a 2 mol / L sodium chloride solution and stir at room temperature for 4 h, with a solid-liquid ratio of 1:3. Then wash twice with deionized water and soak for 24 h, and dry in a vacuum drying oven at 65 °C to obtain pretreated peanut shell powder;

[0087] S1.2: Add 10 parts by weight of the pretreated peanut shell powder to 60 parts by weight of deionized water, mix and place in a high-pressure hydrothermal reaction kettle, react at 180 °C for 12 h, cool the reactant, filter and wash until neutral, and then dry to obtain peanut shell-based hydrochar;

[0088] S1.3: Put 10 parts by weight of peanut shell-based hydrochar into 20 parts by weight of a 3 mol / L potassium carbonate solution, stir and mix at room temperature for 2 h, vacuum dry the mixture and then place it in a tubular furnace, keep it at 700 °C for 1 h under a nitrogen atmosphere, cool, wash until neutral and then dry, and then place it in a nitrogen-oxygen mixed gas and keep it at 420 °C for 1 h to obtain biomass activated carbon;

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

[0090] S2: Preparation of modified biomass activated carbon

[0091] S2.1: Mix 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, place the mixed system at 65 °C, and react with shaking for 2 h to obtain thiolated biomass activated carbon;

[0092] S2.2: Dissolve 2 parts by weight of chitosan in 40 parts by weight of a 5% glacial acetic acid solution by ultrasonic method, then add 30 parts by weight of thiolated biomass activated carbon and disperse ultrasonically for 10 min, and then add 5 parts by weight of manganese dioxide and disperse ultrasonically for 10 min to obtain a mixed solution;

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

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

[0095] S3.1: Let the waste lubricating oil settle and be centrifuged at 60 °C, then heat it to 110 °C for evaporation to obtain pretreated oil. Pump the pretreated oil into a distillation column with an absolute pressure of 1.2 kPa and a temperature of 230 °C for primary vacuum distillation to separate fuel oil. Pump the material after primary vacuum distillation into a distillation column with an absolute pressure of 0.7 kPa and a temperature of 320 °C for secondary vacuum distillation to separate distillate oil and residue;

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

[0097] S3.3: Cool the distillate oil drawn from the secondary vacuum distillation column to 100 °C and then pump it into the tower from the lower inlet of the packed extraction column. The extractant enters the tower from the upper inlet of the packed extraction column. Control the volume flow rate of the distillate oil and the extractant to be 1:1 to obtain the extracted oil;

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

[0099] S4.1: Perform three-stage molecular short-path distillation on the extracted oil. The distances between the hot and cold plates in the three-stage molecular short-path distillation are 15 mm, 25 mm, and 35 mm in sequence, the hot plate temperatures are 180 °C, 200 °C, and 320 °C in sequence, the cold plate temperatures are 20 °C, 80 °C, and 100 °C, and the vacuum degree is 40 Pa in all cases. Collect the distillates at each stage during the distillation process to obtain base oils with different viscosities;

[0100] S4.2: Under the condition of 300 r / min, magnetically stir the base oil at a constant temperature of 125 °C for 40 min, then add modified biomass activated carbon in two portions. The addition amount of modified biomass activated carbon each time is 10% of the mass of the base oil. Stir and mix, evacuate and maintain a vacuum degree of 0.06 MPa for 30 min. Filter and separate the modified biomass activated carbon from the base oil mixture to obtain a semi-finished base oil;

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

[0102] Comparative Example 1

[0103] Compared with Example 1, the difference in Comparative Example 1 is that in Comparative Example 1, step S2 is removed, the modified biomass activated carbon in step S4.2 is replaced with biomass activated carbon of the same mass, and the remaining steps remain unchanged to prepare the finished base oil, denoted as Comparative Example 1.

[0104] Comparative Example 2

[0105] Compared with Example 1, the difference in Comparative Example 2 is that in Comparative Example 2, steps S2.2 - 2.3 are removed, the modified biomass activated carbon in step S4.2 is replaced with thiolated biomass activated carbon of the same mass, and the remaining steps remain unchanged to prepare the finished base oil, denoted as Comparative Example 2.

[0106] Comparative Example 3

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

[0108] Comparative Example 4

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

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

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

[0112]

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

[0114] The low - viscosity base oils in the finished base oils prepared in the comparative examples were analyzed and measured respectively, and the measurement results of the low - viscosity base oil in Example 1 were continued to be used, and the results are shown in Table 2.

[0115] Table 2. Analysis and measurement results of the finished base oils in the comparative examples

[0116] Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Chromaticity 1 5.3 3.6 7.4 1.6 Mass fraction of moisture % Trace 0.02 0.02 0.03 Trace Total amount of metal mmp 47 252 173 483 82 Residual carbon % 0.024 0.23 0.18 0.42 0.06 Acid value mgKOH / g 0.01 0.05 0.03 0.08 0.01 Mass fraction of sulfur element % 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 examples are worse than those of the examples, indicating that the preparation of activated carbon from peanut shells can effectively adsorb the impurities in waste lubricating oil, realize the regeneration of waste lubricating oil, improve the purity of the regenerated base oil. At the same time, after its modification, more adsorption sites can be provided for adsorbing the impurities in waste lubricating oil, improving the adsorption efficiency of the impurities in waste lubricating oil, and significantly improving the purity of the regenerated base oil. It can be seen from the data of Comparative Example 4 that the adsorption and purification effect is better when the modified biomass activity is added in two times.

[0118] The above embodiments merely illustrate the principles and effects of the present invention, rather than limiting the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should 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 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: injecting 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, 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; 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 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.

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 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.

4. 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.

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

6. A process for regenerating base oil from waste lubricating oil according to claim 3, characterized in that: In step S3.2, the mixed alcohol and N-methylpyrrolidone are mixed in a weight ratio of 4:7-8.

7. A process for regenerating base oil from waste lubricating oil according to claim 3, 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.

8. The process for regenerating base oil from waste lubricating oil according to claim 1, 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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