Refining process of regenerated base oil of waste lubricating oil

Abstract

The invention relates to a refining process for regenerated base oil of waste lubricating oil. The refining process comprises the following steps: S1, removing solid wastes: removing the solid wastes in the waste lubricating oil through centrifugal sedimentation; step S2, flocculation treatment: mixing the waste lubricating oil obtained in the step S1 and gel-state polydimethyldiallylammonium chloride (PDMDAAC) powder according to a mass ratio of 1: (10-15), fully and uniformly stirring to enable the gel-state PDMDAAC powder to fully contact and react with the waste lubricating oil, and after the reaction is finished, filtering and settling to separate out the waste lubricating oil and the gel-state PDMDAAC powder containing impurities to obtain the waste lubricating oil; s3, film evaporation: preheating the obtained waste lubricating oil to 130 DEG C, and feeding the preheated waste lubricating oil into a film evaporator for distillation; step S4: short-path distillation; and S5, blending and refining to obtain the regenerated base oil. The method has the advantages of being simple in process, convenient to operate and suitable for industrial production. By accurately controlling the reaction conditions, stable synthesis of the PDMDAAC colloid is realized, and the purity and performance of the product are improved.

Description

Technical Field

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

[0002] Lubricating oil is mainly composed of 80% to 90% base oil and 10% to 20% additives. After 150SN of use, lubricating oil will deteriorate in performance and generate impurities due to physical, chemical or human factors. It can no longer be used and becomes waste lubricating oil. Waste lubricating oil belongs to the HW08 waste mineral oil and mineral oil-containing waste category in my country's "National List of Hazardous Wastes". It contains a variety of toxic and harmful substances, such as heavy metals, benzene series, polycyclic aromatic hydrocarbons, etc. Direct disposal will cause water and soil pollution. On the other hand, waste lubricating oil has a high recycling value and can be regenerated into base oil and other products through appropriate recycling technology. my country's oil resources are insufficient, and its dependence on crude oil abroad exceeds 65%. The recycling of waste lubricating oil can directly save oil resources.

[0003] Although waste lubricating oil contains a large amount of impurities and aging components, its core hydrocarbon components still have certain recycling value. Traditional waste lubricating oil treatment methods such as sedimentation, distillation, acid washing, alkali washing, etc. not only have high energy consumption and limited treatment effect, but also have difficulty in efficiently separating high-quality lubricating oil base oil, resulting in waste of resources. Polydimethyldiallylammonium chloride (PDMDAAC) is an important cationic polymer with a wide range of applications in multiple industrial fields. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a refining process for regenerating base oil from waste lubricating oil. The present invention uses the unique properties of PDMDAAC colloid to react with impurities and harmful substances in the waste lubricating oil to achieve the purpose of purifying the waste lubricating oil and improving its reuse value.

[0005] The present invention is achieved through the following technical solutions: On the one hand, a refining process for regenerating base oil from waste lubricating oil is provided, comprising the following steps:

[0006] Step S1: Removal of solid waste

[0007] Removing solid waste from waste lubricating oil by centrifugal sedimentation;

[0008] Step S2: Flocculation treatment

[0009] The waste lubricating oil obtained in step S1 and the gel-state polydimethyldiallyl ammonium chloride (PDMDAAC) powder are mixed in a mass ratio of 1:10 to 15, and stirred evenly to allow the gel-state PDMDAAC powder to fully contact and react with the waste lubricating oil. After the reaction is completed, the waste lubricating oil and the gel-state PDMDAAC powder containing impurities are separated by filtering and sedimentation to obtain the waste lubricating oil;

[0010] Step S3: Thin film evaporation

[0011] The waste lubricating oil obtained is preheated to 130°C and sent to a thin film evaporator for distillation;

[0012] Step S4: short path distillation,

[0013] Step S5: refining to obtain base oil.

[0014] Through the above technical scheme, the waste lubricating oil is subjected to centrifugal sedimentation, flocculation treatment, thin film evaporation and short-range distillation, refining and other steps, and impurities and harmful substances in the waste lubricating oil are effectively removed, so that the purity of the regenerated base oil is significantly improved. This high-purity base oil can provide better lubrication performance and longer service life in subsequent applications. In addition, the gel-state polydimethyldiallyl ammonium chloride (PDMDAAC) powder used in the flocculation treatment step can efficiently adsorb impurities and harmful substances in the waste lubricating oil, making the subsequent treatment process simpler and more efficient. The refining process of the above-mentioned waste lubricating oil regeneration base oil of the present invention has significant advantages in terms of resource conservation, environmental friendliness and economic benefits. The obtained base oil is superior to the existing technology products in terms of purity, performance and application range, and brings excellent technical effects such as efficient purification, reduced energy consumption and strong environmental protection.

[0015] Among them, the gel-state PDMDAAC powder has the characteristics of high purity, good dispersibility and stability. When the waste lubricating oil and the gel-state PDMDAAC powder are mixed at a mass ratio of 1:10-15, the cationic quaternary ammonium salt groups of PDMDAAC and the anionic particles (such as suspended particles, colloidal particles, etc.) in the waste lubricating oil are electrostatically attracted to form large-particle floccules; PDMDAAC also exhibits a strong adsorption effect on loads such as oil droplets and heavy metal ions, which helps to further remove impurities and pollutants in the waste lubricating oil; therefore, with the addition of PDMDAAC and the electrostatic attraction and adsorption, the impurities in the waste lubricating oil gradually aggregate to form larger floccules, which can effectively improve the regeneration efficiency of the waste lubricating oil and make the regeneration process faster and more thorough. In addition, the use amount of PDMDAAC is small and the efficiency is high, which can effectively remove impurities and suspended matter in the waste lubricating oil and improve the quality and stability of the regenerated oil.

[0016] Furthermore, in step S1, the sedimentation time is 15-48 hours.

[0017] Further, in step S2, the preparation process of the gel-state PDMDAAC powder is as follows:

[0018] a) Raw material preparation: dimethyldiallylammonium chloride monomer solution, comonomer solution, EDTA and deionized water are mixed in a certain proportion, stirred well and prepared into an aqueous solution;

[0019] b) Initiation reaction: the temperature of the aqueous solution obtained in step a) is adjusted to 45-60°C, after nitrogen is passed to deoxygenate, the pre-prepared aqueous initiator solution is slowly added, while stirring is maintained to uniformly disperse the initiator in the reaction system, and the reaction is carried out for 40-46 hours to obtain polydimethyldiallylammonium chloride colloid;

[0020] c) cutting, granulating, drying, crushing and screening the polydimethyldiallylammonium chloride colloid to obtain gel-state PDMDAAC powder.

[0021] Through the above technical solution, by optimizing the raw material ratio and reaction conditions, not only can the generation of by-products be reduced, but also the purity of the product can be improved. The preparation process of the above gel-state PDMDAAC powder is superior to the existing technology in terms of raw material selection and ratio optimization, reaction condition control, initiator selection and addition method, and post-treatment process, which effectively improves production efficiency and reduces production costs.

[0022] Furthermore, in step a), the mass ratio of the dimethyldiallylammonium chloride monomer solution to the comonomer solution is 7-3:3-1.

[0023] Through the above technical solution, the obtained PDMDAAC polymer has stronger adsorption capacity and can better remove impurities and harmful substances in waste lubricating oil; the flocculation effect is better and can form large and dense flocs more quickly, thereby improving the purification efficiency of waste lubricating oil.

[0024] Furthermore, the comonomer solution is an acrylamide monomer (AM) solution, and the concentration of the AM solution is 8%-12%.

[0025] Furthermore, in step a), the amount of EDTA added is 0.15% to 0.2% of the total volume of the reaction system.

[0026] Furthermore, in step b), the initiator is any one of a persulfate initiator and an azo initiator.

[0027] Furthermore, the added amount of the initiator accounts for 0.71% to 0.85% of the mass of the dimethyldiallylammonium chloride monomer.

[0028] Further, in step S4, the short-path distillation is a three-stage molecular short-path distillation; the three-stage molecular short-path distillation includes a first-stage short-path distillation, a second-stage short-path distillation, and a third-stage short-path distillation; the operating conditions of the first-stage short-path distillation are a temperature of 150-250°C and a vacuum of 30-90Pa, and light lubricating oil base oil is distilled out; the operating conditions of the second-stage short-path distillation are a temperature of 180-260°C and a vacuum of 5-20Pa, and medium lubricating oil base oil is distilled out; the operating conditions of the third-stage short-path distillation are a temperature of 200-230°C and a vacuum of 30-50Pa, and heavy lubricating oil base oil is distilled out.

[0029] Preferably, the waste lubricating oil is industrial waste lubricating oil or vehicle waste lubricating oil.

[0030] Beneficial Effects

[0031] The present invention utilizes the unique properties of PDMDAAC colloid to treat waste lubricating oil, and has the advantages of high efficiency, environmental protection, low cost, etc. Nitrogen deoxygenation treatment ensures that the reaction system is carried out under anaerobic conditions, which is conducive to the smooth progress of free radical polymerization reaction. The method is simple in process and convenient in operation, and is suitable for industrial production. The present invention realizes the stable synthesis of PDMDAAC colloid by accurately controlling the reaction conditions, and improves the purity and performance of the product. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The experimental methods without specific conditions in the following examples are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise specified, all percentages, ratios, proportions or parts are by weight.

[0034] Unless otherwise specified, the reagents and raw materials used in the examples and comparative examples of the present invention can be obtained through commercial channels.

[0035] Example 1

[0036] A refining process for regenerating base oil from waste lubricating oil comprises the following steps:

[0037] Step S1: Removal of solid waste

[0038] Weigh 1000 kg of industrial waste lubricating oil, let it settle for 48 hours, and then centrifuge to remove solid waste from the waste lubricating oil;

[0039] Step S2: Flocculation treatment

[0040] The waste lubricating oil obtained in step S1 and the gel-state polydimethyldiallyl ammonium chloride (PDMDAAC) powder are added into a high-speed disperser in a mass ratio of 1:15 for mixing, and the pH value of the waste lubricating oil is adjusted to 7 using dilute hydrochloric acid or sodium hydroxide solution. The stirring speed is 1000 rpm, and the stirring time is 15 minutes. The mixture is fully stirred to make the gel-state PDMDAAC powder and the waste lubricating oil fully contact and react. During the stirring process, the gel-state PDMDAAC powder gradually dissolves and disperses in the waste lubricating oil to form tiny flocculant particles. After standing for 12 minutes, impurities such as suspended matter and colloidal particles in the waste lubricating oil are gradually adsorbed to the flocculant particles to form large and loose flocs. After the reaction is completed, the waste lubricating oil and the gel-state PDMDAAC powder containing impurities are filtered and settled to separate the waste lubricating oil and the impurities, and 950 kg of purified waste lubricating oil is obtained.

[0041] Step S3: Thin film evaporation

[0042] The waste lubricating oil obtained is preheated to 130°C and sent to a thin film evaporator for distillation;

[0043] Step S4: Short Path Distillation

[0044] The waste lubricating oil obtained in step S3 is then heated to 150°C by a heater, and under the condition of a vacuum degree of 45Pa, the light components in the waste lubricating oil begin to evaporate, and the evaporated oil gas is condensed into liquid through a condenser, and the light lubricating oil base oil is collected and then used as the base oil of the waste lubricating oil for standby use. The remaining oil after the first distillation is further heated to 180°C, and when the vacuum degree is 20Pa, the medium components evaporate and condense to obtain the medium lubricating oil base oil; the remaining oil after the second distillation is heated to 200°C, and when the vacuum degree is 50Pa, the heavy components evaporate and condense to obtain the heavy lubricating oil base oil.

[0045] Step S5: Blending and refining

[0046] After the base oil obtained in step S4 is blended according to the target ratio, 20% of the weight of the base oil with a specific surface area of ​​300 m 2 / kg, fly ash with SiO2 content of 45% and calcium oxide content of 18%, is refined at 65℃ for 60min, settled for 10h, and then filtered to obtain regenerated base oil; according to calculation, the yield of regenerated base oil is 98%.

[0047] Based on the above scheme, in step S2, the preparation process of gel-state PDMDAAC powder is as follows:

[0048] a) Raw material preparation: Weigh 70 parts of dimethyldiallylammonium chloride monomer solution and 30 parts of AM solution, mix them, then add deionized water and EDTA in sequence, stir well and prepare an aqueous solution; the amount of EDTA added is 0.15% of the total volume of the reaction system, and the concentration of the AM solution is 12%.

[0049] b) Initiating reaction: adjusting the temperature of the aqueous solution obtained in step a) to 60° C., passing nitrogen to deoxygenate, slowly adding the pre-prepared aqueous solution of ammonium persulfate (NH4)2S2O8, while maintaining stirring, so that the ammonium persulfate (NH4)2S2O8 is evenly dispersed in the reaction system, reacting for 40 hours to obtain polydimethyldiallylammonium chloride colloid; the amount of (NH4)2S2O8 added accounts for 0.85% of the mass of dimethyldiallylammonium chloride monomer.

[0050] c) cutting, granulating, drying, crushing and screening the polydimethyldiallylammonium chloride colloid to obtain gel-state PDMDAAC powder.

[0051] Example 2

[0052] A refining process for regenerating base oil from waste lubricating oil comprises the following steps:

[0053] Step S1: Removal of solid waste

[0054] Weigh 1000 kg of industrial waste lubricating oil, let it settle for 24 hours, and then centrifuge to remove solid waste from the waste lubricating oil;

[0055] Step S2: Flocculation treatment

[0056] The waste lubricating oil obtained in step S1 and the gel-state polydimethyldiallyl ammonium chloride (PDMDAAC) powder are added into a high-speed disperser in a mass ratio of 1:10 for mixing, and the pH value of the waste lubricating oil is adjusted to 8 using dilute hydrochloric acid or sodium hydroxide solution. The stirring speed is 800 rpm, and the stirring time is 10 min. The mixture is fully stirred to make the gel-state PDMDAAC powder and the waste lubricating oil fully contact and react. During the stirring process, the gel-state PDMDAAC powder gradually dissolves and disperses in the waste lubricating oil to form tiny flocculant particles. After standing for 12 min, impurities such as suspended matter and colloidal particles in the waste lubricating oil are gradually adsorbed to the flocculant particles to form large and loose flocs. After the reaction is completed, the waste lubricating oil and the gel-state PDMDAAC powder containing impurities are filtered and settled to separate the waste lubricating oil and the impurities, and 938 kg of purified waste lubricating oil is obtained.

[0057] Step S3: Thin film evaporation

[0058] The waste lubricating oil obtained is preheated to 130°C and sent to a thin film evaporator for distillation;

[0059] Step S4: Short Path Distillation

[0060] The waste lubricating oil obtained in step S3 is then heated to 130°C by a heater, and under the condition of a vacuum degree of 45Pa, the light components in the waste lubricating oil begin to evaporate, and the evaporated oil gas is condensed into liquid through a condenser, and the light lubricating oil base oil is collected and then used as the base oil of the waste lubricating oil for standby use. The remaining oil after the first distillation is further heated to 180°C, and when the vacuum degree is 20Pa, the medium components evaporate and condense to obtain the medium lubricating oil base oil; the remaining oil after the second distillation is heated to 200°C, and when the vacuum degree is 50Pa, the heavy components evaporate and condense to obtain the heavy lubricating oil base oil.

[0061] Step S5: Blending and refining

[0062] After the base oil obtained in step S4 is blended according to the target ratio, 20% of the weight of the base oil is added to the base oil with a specific surface area of ​​350 m 2 / kg, fly ash with SiO2 content of 55% and calcium oxide content of 20%, is refined at 65℃ for 60min, settled for 10h, and then filtered to obtain regenerated base oil; according to calculation, the yield of regenerated base oil is 92%.

[0063] Based on the above scheme, in step S2, the preparation process of gel-state PDMDAAC powder is as follows:

[0064] a) Raw material preparation: Weigh 70 parts of dimethyldiallylammonium chloride monomer solution and 30 parts of AM solution, mix them, then add deionized water and EDTA in sequence, stir well and prepare an aqueous solution; the amount of EDTA added is 0.15% of the total volume of the reaction system, and the concentration of the AM solution is 12%.

[0065] b) Initiating reaction: adjusting the temperature of the aqueous solution obtained in step a) to 60° C., passing nitrogen to deoxygenate, slowly adding the pre-prepared aqueous solution of ammonium persulfate (NH4)2S2O8, while maintaining stirring, so that the ammonium persulfate (NH4)2S2O8 is evenly dispersed in the reaction system, reacting for 40 hours to obtain polydimethyldiallylammonium chloride colloid; the amount of (NH4)2S2O8 added accounts for 0.85% of the mass of dimethyldiallylammonium chloride monomer.

[0066] c) cutting, granulating, drying, crushing and screening the polydimethyldiallylammonium chloride colloid to obtain gel-state PDMDAAC powder.

[0067] Example 3

[0068] A refining process for regenerating base oil from waste lubricating oil comprises the following steps:

[0069] Step S1: Removal of solid waste

[0070] Weigh 1000 kg of waste lubricating oil for vehicles, let it settle for 48 hours, and then centrifuge to remove solid waste in the waste lubricating oil;

[0071] Step S2: Flocculation treatment

[0072] The waste lubricating oil obtained in step S1 and the gel-state polydimethyldiallyl ammonium chloride (PDMDAAC) powder are added into a high-speed disperser at a mass ratio of 1:15 for mixing, and the pH value of the waste lubricating oil is adjusted to 7-9 using dilute hydrochloric acid or sodium hydroxide solution. The stirring speed is 800 rpm, and the stirring time is 18 minutes. The mixture is fully stirred to make the gel-state PDMDAAC powder and the waste lubricating oil fully contact and react. During the stirring process, the gel-state PDMDAAC powder gradually dissolves and disperses in the waste lubricating oil to form tiny flocculant particles. After standing for 12 minutes, impurities such as suspended matter and colloidal particles in the waste lubricating oil are gradually adsorbed to the flocculant particles to form large and loose flocs. After the reaction is completed, the waste lubricating oil and the gel-state PDMDAAC powder containing impurities are filtered and settled to separate the waste lubricating oil and the impurities, and 940 kg of purified waste lubricating oil is obtained.

[0073] Step S3: Thin film evaporation

[0074] The waste lubricating oil obtained is preheated to 130°C and sent to a thin film evaporator for distillation;

[0075] Step S4: Short Path Distillation

[0076] The waste lubricating oil obtained in step S3 is then heated to 180°C by a heater, and under the condition of a vacuum degree of 60Pa, the light components in the waste lubricating oil begin to evaporate, and the evaporated oil gas is condensed into liquid through a condenser, and the light lubricating oil base oil is collected, and then used as the base oil of the waste lubricating oil for standby use. The remaining oil after the first distillation is further heated to 200°C, and when the vacuum degree is 18Pa, the medium components evaporate and condense to obtain the medium lubricating oil base oil; the remaining oil after the second distillation is heated to 230°C, and when the vacuum degree is 42Pa, the heavy components evaporate and condense to obtain the heavy lubricating oil base oil.

[0077] Step S5: Blending and refining

[0078] After the base oil obtained in step S4 is blended according to the target ratio, 8% of the weight of the base oil with a specific surface area of ​​350 m 2 / kg, fly ash with SiO2 content of 55% and calcium oxide content of 20%, is refined at 65℃ for 60min, settled for 10h, and then filtered to obtain regenerated base oil; after calculation, the yield of regenerated base oil is 94%.

[0079] Based on the above scheme, in step S2, the preparation process of gel-state PDMDAAC powder is as follows:

[0080] a) Raw material preparation: Weigh 70 parts of dimethyldiallylammonium chloride monomer solution and 70 parts of AM solution, mix them, then add deionized water and EDTA in sequence, stir well and prepare an aqueous solution; the amount of EDTA added is 0.2% of the total volume of the reaction system, and the concentration of the AM solution is 12%.

[0081] b) Initiating reaction: adjusting the temperature of the aqueous solution obtained in step a) to 60° C., passing nitrogen to deoxygenate, slowly adding the pre-prepared aqueous solution of ammonium persulfate (NH4)2S2O8, while maintaining stirring, so that the ammonium persulfate (NH4)2S2O8 is evenly dispersed in the reaction system, reacting for 40 hours to obtain polydimethyldiallylammonium chloride colloid; the amount of (NH4)2S2O8 added accounts for 0.85% of the mass of dimethyldiallylammonium chloride monomer.

[0082] c) cutting, granulating, drying, crushing and screening the polydimethyldiallylammonium chloride colloid to obtain gel-state PDMDAAC powder.

[0083] Example 4

[0084] A refining process for regenerating base oil from waste lubricating oil comprises the following steps:

[0085] Step S1: Removal of solid waste

[0086] Weigh 1000 kg of waste lubricating oil for vehicles, let it settle for 48 hours, and then centrifuge to remove solid waste in the waste lubricating oil;

[0087] Step S2: Flocculation treatment

[0088] The waste lubricating oil obtained in step S1 and the gel-state polydimethyldiallyl ammonium chloride (PDMDAAC) powder are added into a high-speed disperser at a mass ratio of 1:15 for mixing, and the pH value of the waste lubricating oil is adjusted to 7-9 using dilute hydrochloric acid or sodium hydroxide solution. The stirring speed is 800 rpm, and the stirring time is 18 minutes. The mixture is fully stirred to make the gel-state PDMDAAC powder and the waste lubricating oil fully contact and react. During the stirring process, the gel-state PDMDAAC powder gradually dissolves and disperses in the waste lubricating oil to form tiny flocculant particles. After standing for 12 minutes, impurities such as suspended matter and colloidal particles in the waste lubricating oil are gradually adsorbed to the flocculant particles to form large and loose flocs. After the reaction is completed, the waste lubricating oil and the gel-state PDMDAAC powder containing impurities are filtered and settled to separate the waste lubricating oil and the impurities, and 940 kg of purified waste lubricating oil is obtained.

[0089] Step S3: Thin film evaporation

[0090] The waste lubricating oil obtained is preheated to 130°C and sent to a thin film evaporator for distillation;

[0091] Step S4: Short Path Distillation

[0092] The waste lubricating oil obtained in step S3 is then heated to 190°C by a heater, and under the condition of a vacuum degree of 85Pa, the light components in the waste lubricating oil begin to evaporate, and the evaporated oil gas is condensed into liquid through a condenser, and the light lubricating oil base oil is collected and then used as the base oil of the waste lubricating oil for standby use. The remaining oil after the first distillation is further heated to 210°C, and when the vacuum degree is 18Pa, the medium components evaporate and condense to obtain the medium lubricating oil base oil; the remaining oil after the second distillation is heated to 230°C, and when the vacuum degree is 45Pa, the heavy components evaporate and condense to obtain the heavy lubricating oil base oil.

[0093] Step S5: Blending and refining

[0094] After the base oil obtained in step S4 is blended according to the target ratio, 8% of the weight of the base oil with a specific surface area of ​​350 m 2 / kg, fly ash with SiO2 content of 55% and calcium oxide content of 20%, was refined at 65°C for 60min, settled for 10h, and then filtered to obtain regenerated base oil; after calculation, the yield of regenerated base oil was 90.25%.

[0095] Based on the above scheme, in step S2, the preparation process of gel-state PDMDAAC powder is as follows:

[0096] Preparation of raw materials: Weigh 70 parts of dimethyldiallylammonium chloride monomer solution and 70 parts of AM solution, mix them, then add deionized water and EDTA in sequence, stir well to prepare an aqueous solution; the amount of EDTA added is 0.2% of the total volume of the reaction system, and the concentration of the AM solution is 10%.

[0097] b) Initiating reaction: adjusting the temperature of the aqueous solution obtained in step a) to 60° C., passing nitrogen to deoxygenate, slowly adding the pre-prepared aqueous solution of ammonium persulfate (NH4)2S2O8, while maintaining stirring, so that the ammonium persulfate (NH4)2S2O8 is evenly dispersed in the reaction system, reacting for 40 hours to obtain polydimethyldiallylammonium chloride colloid; the amount of (NH4)2S2O8 added accounts for 0.85% of the mass of dimethyldiallylammonium chloride monomer.

[0098] c) cutting, granulating, drying, crushing and screening the polydimethyldiallylammonium chloride colloid to obtain gel-state PDMDAAC powder.

[0099] Comparative Example 1

[0100] Compared with Example 1, the addition of gel-state polydimethyldiallyl ammonium chloride (PDMDAAC) powder is missing; according to calculation, the yield of the regenerated base oil is 80%.

[0101] Comparative Example 2

[0102] Compared with Example 1, the preparation of the gel-state polydimethyldiallylammonium chloride (PDMDAAC) powder lacks the addition of comonomer; and according to calculation, the yield of the regenerated base oil is 86%.

[0103] Comparative Example 3

[0104] Compared with Example 2, the short-path distillation process is omitted, the waste lubricating oil obtained in step S3 is directly blended and refined, and 20% of the weight of the waste lubricating oil with a specific surface area of ​​280 m 2 / kg, fly ash with SiO2 content of 45% and calcium oxide content of 10%, is refined at 65℃ for 60min, settled for 10h, and then filtered to obtain regenerated base oil; after calculation, the yield of regenerated base oil is 89%.

[0105] Effect Example

[0106] The above-mentioned Examples 1 to 4 and Comparative Examples 1 to 3 were subjected to performance tests, and the performance characteristics of the base oil are shown in the following table:

[0107]

[0108]

[0109] Notice:

[0110] Pretreatment of waste lubricating oil: Using samples before and after centrifugal sedimentation, the impurity removal rate of the waste lubricating oil was calculated by weighing method.

[0111] Oil quality analysis: Physical and chemical properties of oil samples after each step of treatment are analyzed, including viscosity, acid value, moisture and other indicators.

[0112] Yield and purity testing: The yield and purity of the final base oil are determined by weighing and laboratory analysis.

[0113] It can be seen from the above table that the present invention realizes the efficient removal of impurities such as suspended matter and colloidal particles in waste lubricating oil by utilizing gel-state polydimethyldiallyl ammonium chloride (PDMDAAC) powder, making the appearance of the regenerated base oil clear and transparent, and the color number is significantly reduced. It can be seen from Examples 1 to 4 that the regenerated base oil has a high viscosity index, indicating that its viscosity changes less at different temperatures, which is conducive to ensuring the stable operation of mechanical equipment under different working conditions. The present invention realizes the efficient recovery and utilization of waste lubricating oil through reasonable process design and optimization, and the yield is significantly improved, the production cost is reduced, and the economic benefit is improved.

[0114] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A refining process for regenerating base oil from waste lubricating oil, characterized in that: The following steps are involved: Step S1: Removal of solid waste Removing solid waste from waste lubricating oil by centrifugal sedimentation; Step S2: Flocculation treatment The waste lubricating oil obtained in step S1 and the gel-state polydimethyldiallyl ammonium chloride (PDMDAAC) powder are mixed in a mass ratio of 1:10 to 15, and stirred evenly to allow the gel-state PDMDAAC powder to fully contact and react with the waste lubricating oil. After the reaction is completed, the waste lubricating oil and the gel-state PDMDAAC powder containing impurities are separated by filtering and sedimentation to obtain the waste lubricating oil; Step S3: Thin film evaporation The waste lubricating oil obtained is preheated to 130°C and sent to a thin film evaporator for distillation; Step S4: short path distillation; Step S5: Blending and refining The base oil obtained in step S4 is blended, and then 5%-20% of fly ash by weight of the base oil is added, refined at 45-65° C. for 50-80 minutes, and filtered after settling for 8-12 hours to obtain the regenerated base oil.

2. The refining process for regenerating base oil from waste lubricating oil according to claim 1, characterized in that: In step S2, the preparation process of the gel-state PDMDAAC powder is as follows: a) Raw material preparation: dimethyldiallylammonium chloride monomer solution, comonomer solution, EDTA and deionized water are mixed in a certain proportion, stirred well and prepared into an aqueous solution; b) Initiation reaction: the temperature of the aqueous solution obtained in step a) is adjusted to 45-60°C, after nitrogen is passed to deoxygenate, the pre-prepared aqueous initiator solution is slowly added, while stirring is maintained to uniformly disperse the initiator in the reaction system, and the reaction is carried out for 40-46 hours to obtain polydimethyldiallylammonium chloride colloid; c) cutting, granulating, drying, crushing and screening the polydimethyldiallylammonium chloride colloid to obtain gel-state PDMDAAC powder.

3. The refining process for regenerating base oil from waste lubricating oil according to claim 3, characterized in that: In step a), the mass ratio of the dimethyldiallylammonium chloride monomer solution to the comonomer solution is 7-3:3-1.

4. The refining process for regenerating base oil from waste lubricating oil according to claim 4, characterized in that: The comonomer solution is an acrylamide monomer (AM) solution, and the concentration of the AM solution is 8%-12%.

5. The refining process for regenerating base oil from waste lubricating oil according to claim 3, characterized in that: In step a), the amount of EDTA added is 0.15% to 0.2% of the total volume of the reaction system.

6. The process for refining base oil from waste lubricating oil according to claim 3, characterized in that: In step b), the initiator is any one of a persulfate initiator and an azo initiator.

7. The process for refining base oil from waste lubricating oil according to claim 7, characterized in that: The added amount of the initiator accounts for 0.71% to 0.85% of the mass of the dimethyldiallylammonium chloride monomer.

8. The process for refining base oil from waste lubricating oil according to claim 1, characterized in that: In step S4, the short-path distillation is a three-stage molecular short-path distillation; the three-stage molecular short-path distillation includes a first-stage short-path distillation, a second-stage short-path distillation, and a third-stage short-path distillation; the first-stage short-path distillation operating conditions are a temperature of 150-250°C and a vacuum degree of 30-90Pa, and light lubricating oil base oil is distilled out; the second-stage short-path distillation operating conditions are a temperature of 180-260°C and a vacuum degree of 5-20Pa, and medium-quality lubricating oil base oil is distilled out; the third-stage short-path distillation operating conditions are a temperature of 200-230°C and a vacuum degree of 30-50Pa, and heavy lubricating oil base oil is distilled out.

9. The process for refining base oil from waste lubricating oil according to claim 1, characterized in that: In step S5, the specific surface area of ​​the fly ash is 280-350m 2 / kg, SiO2 content is 30% to 55%, and calcium oxide content is 8% to 20%.

10. The process for refining base oil from waste lubricating oil according to any one of claims 1 to 9, characterized in that: The waste lubricating oil is industrial waste lubricating oil or vehicle waste lubricating oil.

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