A refining process for base oil from used lubricating oil

Abstract

The present application relates to a kind of waste lubricating oil regeneration base oil refining process, comprising the following steps: step S1: remove solid waste: remove solid waste in waste lubricating oil by centrifugal sedimentation;Step S2: flocculation treatment: the waste lubricating oil obtained in step S1 and gel state polydimethyl diallyl ammonium chloride (PDMDAAC) powder are mixed according to the proportion of 1:10-15 by mass ratio, fully stirred evenly, make gel state PDMDAAC powder and waste lubricating oil fully contact reaction, after reaction, filter, sedimentation separation waste lubricating oil and impurity-containing gel state PDMDAAC powder, obtain waste lubricating oil;Step S3: thin film evaporation: the obtained waste lubricating oil is preheated to 130 DEG C, and sent into thin film evaporator and carries out distillation;Step S4: short path distillation;Step S5: blending and refining, and the regenerated base oil is obtained.The present application has the advantages of simple process, convenient operation, and is suitable for industrial production.The present application realizes the stable synthesis of PDMDAAC colloid by accurately controlling reaction conditions, and improves the purity and performance of product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of regenerating lubricating oil, and particularly relates to a refining process for regenerating base oil from waste lubricating oil. BACKGROUND

[0002] Lubricating oil is mainly composed of 80-90% base oil and 10-20% additives. After being used for 150SN, the performance of lubricating oil will deteriorate due to physical and chemical factors or human factors, impurities will be generated, and the lubricating oil cannot be used any more and becomes waste lubricating oil. Waste lubricating oil belongs to the HW08 waste mineral oil and mineral oil-containing waste category in the National Hazardous Waste List of China, and contains various 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 high recycling value and can be regenerated into base oil and other products through appropriate regeneration technology. China is short of oil resources, and the dependence on foreign crude oil is more than 65%, while 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, the core hydrocarbon components still have certain recycling value. Traditional waste lubricating oil treatment methods such as sedimentation, distillation, acid washing, and alkali washing have problems such as high energy consumption, limited treatment effect, and difficulty in efficiently separating high-quality lubricating oil base oil, resulting in resource waste. Polydimethyl diallyl ammonium chloride (PDMDAAC) is an important cationic polymer and has a wide range of applications in various industries. SUMMARY

[0004] The present application aims to overcome the deficiencies in the prior art and provide a refining process for regenerating base oil from waste lubricating oil. The unique properties of PDMDAAC colloid interact with impurities and harmful substances in waste lubricating oil to purify the waste lubricating oil and improve its recycling value.

[0005] The present application is achieved by the following technical solutions: on the one hand, a refining process for regenerating base oil from waste lubricating oil is provided, which includes the following steps:

[0006] Step S1: removing solid waste

[0007] The solid waste in the waste lubricating oil is removed by centrifugal sedimentation;

[0008] Step S2: flocculation treatment

[0009] The waste lubricating oil obtained in step S1 and gelled polydimethyl diallyl ammonium chloride (PDMDAAC) powder are mixed in a mass ratio of 1:10-15, fully stirred and uniformly mixed, so that the gelled PDMDAAC powder fully contacts and reacts with the waste lubricating oil. After the reaction is completed, the waste lubricating oil and the gelled PDMDAAC powder containing impurities are separated by filtration and sedimentation, and the waste lubricating oil is obtained.

[0010] Step S3: thin film evaporation

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

[0012] Step S4: short path distillation,

[0013] Step S5: refining, and the base oil is obtained.

[0014] Through the above technical scheme, the impurities and harmful substances in the waste lubricating oil are effectively removed through the steps of centrifugal sedimentation, flocculation treatment, thin film evaporation, short path distillation, and refining, 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 gelled polydimethyl diallyl 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 more simple and efficient. The above-mentioned waste lubricating oil regeneration base oil refining process of the present application has significant advantages in resource conservation, environmental friendliness and economic benefits, and the obtained base oil is superior to the products of the prior art in purity, performance and application range, and brings excellent technical effects such as efficient purification, energy consumption reduction and strong environmental protection.

[0015] The gelled PDMDAAC powder has the characteristics of high purity, good dispersibility and stability. The waste lubricating oil is mixed with the gelled PDMDAAC powder in a mass ratio of 1:10-15. The cationic quaternary ammonium salt group of PDMDAAC has electrostatic attraction with anionic particles (such as suspended particles, colloidal particles, etc.) in the waste lubricating oil, forming large-particle flocculants. PDMDAAC also exhibits strong adsorption to oil droplets, heavy metal ions and other loads, 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 flocculants, which can effectively improve the regeneration efficiency of the waste lubricating oil and make the regeneration process more rapid and thorough. And the use amount of PDMDAAC is less and the efficiency is high, which can effectively remove the impurities and suspended solids in the waste lubricating oil, and improve the quality and stability of the regenerated oil.

[0016] Further, in step S1, the sedimentation time is 15-48 h.

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

[0018] a) Raw material preparation: mix dimethyl diallyl ammonium chloride monomer solution, comonomer solution, EDTA, and deionized water according to a certain proportion, fully stir to uniform, and prepare an aqueous solution;

[0019] b) Initiation reaction: adjust the temperature of the aqueous solution obtained in step a) to 45-60℃, remove oxygen by nitrogen, then slowly add the prepared initiator aqueous solution, while keeping stirring, make the initiator uniformly dispersed in the reaction system, react for 40-46h, and obtain polydimethyl diallyl ammonium chloride colloid;

[0020] c) The polydimethyl diallyl ammonium chloride colloid is cut, granulated, dried, crushed and sieved to obtain the gel PDMDAAC powder.

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

[0022] Further, in step a), the mass ratio of the dimethyl diallyl ammonium 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, can better remove impurities and harmful substances in waste lubricating oil; has better flocculation effect, can form large and dense flocs faster, and improve the purification efficiency of waste lubricating oil.

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

[0025] Further, in step a), the addition amount of the EDTA accounts for 0.15%-0.2% of the total volume of the reaction system.

[0026] Further, in step b), the initiator is any one of persulfate initiators and azo initiators.

[0027] Further, the addition amount of the initiator accounts for 0.71%-0.85% of the mass of dimethyl diallyl ammonium 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 comprises 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 is operated at a temperature of 150-250 DEG C and a vacuum degree of 30-90 Pa to fractionate light lubricating oil base stock; the second-stage short path distillation is operated at a temperature of 180-260 DEG C and a vacuum degree of 5-20 Pa to evaporate medium lubricating oil base stock; and the third-stage short path distillation is operated at a temperature of 200-230 DEG C and a vacuum degree of 30-50 Pa to evaporate heavy lubricating oil base stock.

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

[0030] Advantages

[0031] The present application utilizes the unique properties of PDMDAAC colloid to treat waste lubricating oil, and has the advantages of high efficiency, environmental protection, and low cost. The nitrogen oxygen removal treatment ensures that the reaction system is carried out under oxygen-free conditions, which is conducive to the smooth progress of the free radical polymerization reaction. The method is simple in process and convenient in operation, and is suitable for industrial production. The present application 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 scheme and advantages of the present application more clear, the present application will be further described in detail below in combination with specific examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0033] Based on the examples in the present application, all other examples obtained by those skilled in the art without making creative efforts belong to the scope of protection of the present application. The experimental methods not specified in the following examples are usually carried out according to conventional conditions or according to the conditions recommended by the manufacturers. Unless otherwise specified, all percentages, ratios, proportions or parts are by weight.

[0034] The reagents and raw materials used in the examples and comparative examples of the present application can be obtained through commercial channels unless otherwise specified.

[0035] Example 1

[0036] A refining process of waste lubricating oil regenerated base oil comprises the following steps:

[0037] Step S1: removing solid waste

[0038] 1000 kg of industrial waste lubricating oil was weighed, and after standing and settling for 48 h, the solid waste in the waste lubricating oil was removed by centrifugation.

[0039] Step S2: flocculation treatment

[0040] The waste lubricating oil and the gelatinous PDMDAAC powder obtained in step S1 were mixed in a high-speed dispersion machine at a mass ratio of 1:15, and the pH value of the waste lubricating oil was adjusted to 7 using dilute hydrochloric acid or sodium hydroxide solution. The stirring speed was 1000 rpm, and the stirring time was 15 min. The gelatinous PDMDAAC powder was fully stirred and uniformly contacted with the waste lubricating oil. During the stirring process, the gelatinous PDMDAAC powder was gradually dissolved and dispersed in the waste lubricating oil to form small flocculant particles. After standing for 12 min, the impurities such as suspended solids and colloidal particles in the waste lubricating oil were gradually adsorbed onto the flocculant particles to form large and loose flocs. After the reaction was completed, the waste lubricating oil and the gelatinous PDMDAAC powder containing impurities were separated by filtration and sedimentation after standing for 30 min, and 950 kg of purified waste lubricating oil was obtained.

[0041] Step S3: thin film evaporation

[0042] The obtained waste lubricating oil was preheated to 130℃ and sent into a thin film evaporator for distillation.

[0043] Step S4: short path distillation

[0044] The waste lubricating oil obtained in step S3 was heated to 150℃ by a heater, and the light components in the waste lubricating oil began to evaporate under the condition of a vacuum degree of 45 Pa. The evaporated oil gas was condensed into liquid by a condenser, and light lubricating oil base oil was collected as a standby base oil of the waste lubricating oil. The remaining oil after the first distillation was continuously heated to 180℃, and the medium components were evaporated and condensed under the condition of a vacuum degree of 20 Pa to obtain medium lubricating oil base oil. The remaining oil after the second distillation was heated to 200℃, and the heavy components were evaporated and condensed under the condition of a vacuum degree of 50 Pa to obtain heavy lubricating oil base oil.

[0045] Step S5: blending and refining

[0046] The base oil obtained in step S4 was blended according to the target proportion, and 20% of fly ash with a specific surface area of 300 m 2 / kg, a SiO2 content of 45%, and a calcium oxide content of 18% was added based on the weight of the base oil. The mixture was refined at 65℃ for 60 min, and after standing for 10 h, the regenerated base oil was obtained by filtration. The yield of the regenerated base oil was calculated to be 98%.

[0047] On the basis of the above scheme, in step S2, the preparation process of the gelatinous PDMDAAC powder is as follows:

[0048] a) Preparation of raw materials: 70 parts of dimethyl diallyl ammonium chloride monomer solution and 30 parts of AM solution were mixed, and then deionized water and EDTA were added in turn, and fully stirred to prepare an aqueous solution; the addition amount of EDTA was 0.15% of the total volume of the reaction system, and the concentration of AM solution was 12%.

[0049] b) Initiation of reaction: the temperature of the aqueous solution obtained in step a) was adjusted to 60℃, and then deoxygenated by nitrogen blowing, and then ammonium persulfate (NH4)2S2O8 aqueous solution prepared in advance was slowly added while stirring, so that ammonium persulfate (NH4)2S2O8 was uniformly dispersed in the reaction system, and the reaction was carried out for 40h to obtain polydimethyl diallyl ammonium chloride colloid; the addition amount of (NH4)2S2O8 was 0.85% of the mass of dimethyl diallyl ammonium chloride monomer.

[0050] c) The polydimethyl diallyl ammonium chloride colloid was cut, granulated, dried, and crushed and sieved to obtain gel PDMDAAC powder.

[0051] Example 2

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

[0053] Step S1: removing solid waste

[0054] 1000kg of industrial waste lubricating oil was weighed, and after standing and settling for 24h, the solid waste in the waste lubricating oil was removed by centrifugation;

[0055] Step S2: flocculation treatment

[0056] The waste lubricating oil obtained in step S1 and gel PDMDAAC powder were mixed in a high-speed disperser at a mass ratio of 1:10, and dilute hydrochloric acid or sodium hydroxide solution was used to adjust the pH value of the waste lubricating oil to 8, the stirring speed was 800rpm, and the stirring time was 10min, so that the gel PDMDAAC powder was fully stirred and uniformly mixed with the waste lubricating oil to fully contact and react; during the stirring process, the gel PDMDAAC powder was gradually dissolved and dispersed in the waste lubricating oil to form small flocculant particles; after standing for 12min, the impurities such as suspended matter and colloidal particles in the waste lubricating oil were gradually adsorbed onto the flocculant particles to form large and loose flocs; after the reaction was completed, the waste lubricating oil and the gel PDMDAAC powder containing impurities were separated by filtration and sedimentation after standing for 30min, and 938kg of purified waste lubricating oil was obtained.

[0057] Step S3: thin film evaporation

[0058] The obtained waste lubricating oil was preheated to 130℃ and sent into a thin film evaporator for distillation.

[0059] Step S4: Short path distillation

[0060] The waste lubricating oil obtained in step S3 is heated to 130℃ by a heater, and the light components in the waste lubricating oil start to evaporate under the condition of a vacuum degree of 45 Pa. The evaporated oil gas is condensed into liquid by a condenser, and the light lubricating oil base oil is collected and used as the base oil of the waste lubricating oil. The remaining oil after the first distillation is continuously heated to 180℃, and the medium components evaporate and condense under the condition of a vacuum degree of 20 Pa, and the medium lubricating oil base oil is obtained. The remaining oil after the second distillation is heated to 200℃, and the heavy components evaporate and condense under the condition of a vacuum degree of 50 Pa, and the heavy lubricating oil base oil is obtained.

[0061] Step S5: Blending and refining

[0062] The base oil obtained in step S4 is blended according to the target proportion, and 20% of the base oil by weight is added to the fly ash with a specific surface area of 350 m 2 / kg, a SiO2 content of 55%, and a calcium oxide content of 20%, and refined at 65℃ for 60 min. After settling for 10 h, filtration is performed to obtain the regenerated base oil. The yield of the regenerated base oil is calculated to be 92%.

[0063] On the basis of the above scheme, in step S2, the preparation process of the gel PDMDAAC powder is as follows:

[0064] a) Raw material preparation: 70 parts of dimethyl diallyl ammonium chloride monomer solution and 30 parts of AM solution are mixed, and then deionized water and EDTA are added in sequence, and fully stirred to prepare an aqueous solution; the addition amount of EDTA is 0.15% of the total volume of the reaction system, and the concentration of the AM solution is 12%.

[0065] b) Initiation of reaction: the temperature of the aqueous solution obtained in step a) is adjusted to 60℃, and nitrogen is introduced to remove oxygen, and then ammonium persulfate (NH4)2S2O8 aqueous solution is slowly added while stirring to make ammonium persulfate (NH4)2S2O8 uniformly dispersed in the reaction system, and the reaction is carried out for 40 h to obtain polydimethyl diallyl ammonium chloride colloid; the addition amount of (NH4)2S2O8 is 0.85% of the mass of dimethyl diallyl ammonium chloride monomer.

[0066] c) The polydimethyl diallyl ammonium chloride colloid is cut, granulated, dried, and crushed and sieved to obtain the gel PDMDAAC powder.

[0067] Example 3

[0068] A waste lubricating oil regeneration base oil refining process, comprising the following steps:

[0069] Step S1: Removing solid waste

[0070] Take 1000 kg of waste lubricating oil for vehicles, and after standing for 48 h, remove the solid waste in the waste lubricating oil by centrifugation;

[0071] Step S2: flocculation treatment

[0072] The waste lubricating oil obtained in step S1 and the gelatinous polydimethyl diallyl ammonium chloride (PDMDAAC) powder are mixed in a high-speed dispersion machine at a mass ratio of 1:15, 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, the stirring time is 18 min, and the gelatinous PDMDAAC powder is fully stirred and uniformly mixed to fully contact and react with the waste lubricating oil; during the stirring process, the gelatinous PDMDAAC powder is gradually dissolved and dispersed in the waste lubricating oil to form tiny flocculants; after standing for 12 min, the impurities such as suspended matter and colloidal particles in the waste lubricating oil are gradually adsorbed to the flocculants to form large and loose flocs; after the reaction is completed, the waste lubricating oil and the gelatinous PDMDAAC powder containing impurities are separated by filtration and sedimentation after standing for 30 min, and 940 kg of purified waste lubricating oil is obtained.

[0073] Step S3: thin film evaporation

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

[0075] Step S4: short path distillation

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

[0077] Step S5: blending and refining

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

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

[0080] a) Raw material preparation: Weigh 70 parts of dimethyl diallyl ammonium chloride monomer solution and 70 parts of AM solution, mix them, and then add deionized water and EDTA in sequence. Stir thoroughly to prepare an aqueous solution. The amount of EDTA added accounts for 0.2% of the total volume of the reaction system, and the concentration of AM solution is 12%.

[0081] b) Initiating the reaction: Adjust the temperature of the aqueous solution obtained in step a) to 60°C, remove oxygen by purging with nitrogen, and slowly add the pre-prepared ammonium persulfate (NH4)2S2O8 aqueous solution while stirring to ensure that the ammonium persulfate (NH4)2S2O8 is uniformly dispersed in the reaction system. React for 40 hours to obtain polydimethyldiallyl ammonium chloride colloid; the amount of (NH4)2S2O8 added accounts for 0.85% of the mass of the dimethyldiallyl ammonium chloride monomer.

[0082] c) The polydimethyldiallylammonium chloride colloid is cut, granulated, dried, pulverized and sieved to obtain gel-state PDMDAAC powder.

[0083] Example 4

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

[0085] Step S1: Remove solid waste

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

[0087] Step S2: Flocculation Treatment

[0088] The waste lubricating oil obtained in step S1 and gelled polydimethyldiallylammonium chloride (PDMDAAC) powder were added to a high-speed disperser at a mass ratio of 1:15 and mixed. The pH value of the waste lubricating oil was adjusted to 7-9 using dilute hydrochloric acid or sodium hydroxide solution. The stirring speed was 800 rpm and the stirring time was 18 min to ensure thorough mixing and complete contact and reaction between the gelled PDMDAAC powder and the waste lubricating oil. During the stirring process, the gelled PDMDAAC powder gradually dissolved and dispersed in the waste lubricating oil, forming tiny flocculant particles. After standing for 12 min, suspended solids, colloidal particles, and other impurities in the waste lubricating oil were gradually adsorbed onto the flocculant particles, forming large and loose flocs. After the reaction was completed, the mixture was allowed to stand for 30 min, and then filtered and settled to separate the waste lubricating oil and the impurity-containing gelled PDMDAAC powder, yielding 940 kg of purified waste lubricating oil.

[0089] Step S3: Thin film evaporation

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

[0091] Step S4: short path distillation

[0092] The waste lubricating oil obtained in step S3 is heated to 190°C by a heater, and under the condition of a vacuum degree of 85 Pa, the light components in the waste lubricating oil start to evaporate, the evaporated oil gas is condensed into liquid by a condenser, and the light lubricating oil base oil is collected and used as the base oil of the waste lubricating oil. The remaining oil after the first distillation is continuously heated to 210°C, and under the condition of a vacuum degree of 18 Pa, 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 under the condition of a vacuum degree of 45 Pa, the heavy components evaporate and condense to obtain the heavy lubricating oil base oil.

[0093] Step S5: blending and refining

[0094] The base oil obtained in step S4 is blended according to the target proportion, and 8% of the base oil by weight is added to the fly ash with a specific surface area of 350 m 2 / kg, a SiO2 content of 55%, and a calcium oxide content of 20%, and refined at 65°C for 60 min, and after settling for 10 h, filtering to obtain the regenerated base oil; it is calculated that the yield of the regenerated base oil is 90.25%.

[0095] On the basis of the above scheme, in step S2, the preparation process of the gel PDMDAAC powder is as follows:

[0096] Raw material preparation: 70 parts of dimethyl diallyl ammonium chloride monomer solution and 70 parts of AM solution are mixed, and then deionized water and EDTA are added in sequence, and fully stirred to prepare an aqueous solution; the addition amount of EDTA is 0.2% of the total volume of the reaction system, and the concentration of the AM solution is 10%.

[0097] b) initiating the reaction: the temperature of the aqueous solution obtained in step a) is adjusted to 60°C, oxygen is removed by nitrogen blowing, and then the previously prepared ammonium persulfate (NH4)2S2O8 aqueous solution is slowly added while stirring to make ammonium persulfate (NH4)2S2O8 uniformly dispersed in the reaction system, and the reaction is carried out for 40 h to obtain a polydimethyl diallyl ammonium chloride colloid; the addition amount of (NH4)2S2O8 is 0.85% of the mass of dimethyl diallyl ammonium chloride monomer.

[0098] c) the polydimethyl diallyl ammonium chloride colloid is cut, granulated, dried, and crushed and sieved to obtain a gel PDMDAAC powder.

[0099] Comparative Example 1

[0100] Compared with Example 1, the addition of gelatinous polydimethyl diallyl ammonium chloride (PDMDAAC) powder is absent; the yield of the regenerated base oil is 80% by calculation.

[0101] Comparative Example 2

[0102] Compared with Example 1, the addition of comonomer is absent in the preparation of gelatinous polydimethyl diallyl ammonium chloride (PDMDAAC) powder; the yield of the regenerated base oil is 86% by calculation.

[0103] Comparative Example 3

[0104] Compared with Example 2, the process of short path distillation is absent, the waste lubricating oil obtained in step S3 is directly subjected to blending and refining, and 20% by weight of the waste lubricating oil is added with fly ash having a specific surface area of 280 m 2 / kg, a SiO2 content of 45%, and a calcium oxide content of 10%, and is refined at 65°C for 60 min, and after settling for 10 h, is filtered to obtain the regenerated base oil; the yield of the regenerated base oil is 89% by calculation.

[0105] Effect Example

[0106] The above Examples 1-4 and Comparative Examples 1-3 are subjected to performance testing, and the performance of the base oil is characterized as shown in the following table:

[0107]

[0108]

[0109] Note:

[0110] Pretreatment of waste lubricating oil: the samples before and after centrifugal settling are used to calculate the impurity removal rate of the waste lubricating oil by weighing method.

[0111] Oil quality analysis: the oil samples after each treatment are subjected to physicochemical property analysis, including viscosity, acid value, moisture content, and the like.

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

[0113] It can be known from the above table analysis that the application realizes efficient removal of impurities such as suspended matter and colloidal particles in waste lubricating oil by using gelatinous polydimethyl diallyl ammonium chloride (PDMDAAC) powder, so that the appearance of the regenerated base oil is clear and transparent, and the color number is significantly reduced. It can be known from Examples 1-4 that the regenerated base oil has a relatively high viscosity index, indicating that the viscosity change at different temperatures is small, which is beneficial to ensure the stable operation of mechanical equipment under different working conditions. The application realizes efficient recovery and utilization of waste lubricating oil by reasonable process design and optimization, significantly improves the yield, reduces the production cost, and improves the economic benefit.

[0114] Finally, it should be pointed out that: the above only for the preferred embodiments of the application, and not for limiting the application, although the application is described in detail with reference to the foregoing embodiments, for those skilled in the art, the technical solution recorded in the foregoing embodiments can still be modified, or some technical features can be replaced, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application, should be included in the protection scope of the application.

Claims

1. A refining process for the production of base oil from used lubricating oil, characterized in that, The method comprises the following steps: Step S1: removing solid waste from the waste lubricating oil; Step S2: flocculation treatment; Step S3: thin film evaporation; Step S4: short path distillation; Step S5: blending and refining; In step S2, the preparation process of the gelatinous PDMDAAC powder is as follows: a) raw material preparation: mix dimethyl diallyl ammonium chloride monomer solution, comonomer solution, EDTA, and deionized water in a certain proportion, fully stir and uniformly mix, and prepare an aqueous solution; b) initiating reaction: adjust the temperature of the aqueous solution obtained in step a) to 45-60 DEG C, remove oxygen by nitrogen blowing, slowly add the prepared initiator aqueous solution, and keep stirring to uniformly disperse the initiator in the reaction system; react for 40-46 h to obtain polydimethyl diallyl ammonium chloride colloid; c) cut, granulate, dry, and crush and sieve the polydimethyl diallyl ammonium chloride colloid to obtain the gelatinous PDMDAAC powder; In step S5, the specific surface area of the fly ash is 280-350 m 2 / kg, the SiO2 content is 30%-55%, and the calcium oxide content is 8%-20%. Acrylamide In step b), the initiator is any one of persulfate initiators and azo initiators; the addition amount of the initiator is 0.71%-0.85% of the mass of dimethyl diallyl ammonium chloride monomer. In step a), the addition amount of EDTA is 0.15%-0.2% of the total volume of the reaction system. The waste lubricating oil is industrial waste lubricating oil or vehicle waste lubricating oil. ​ In step a), the mass ratio of the dimethyl diallyl ammonium chloride monomer solution: co-monomer solution is 7-3:3-1; the co-monomer solution is an acrylamide monomer (AM) solution, and the concentration of the AM solution is 8%-12%. ​ ​ ​ 2. The refining process of waste lubricating oil to base oil of claim 1, wherein, ​ 3. The refining process of the spent lubricating oil base oil according to any one of claims 1 to 2, characterized in that, ​

Images