Method and device for regenerating waste white oil

Abstract

The invention relates to the field of waste oil regeneration, and discloses a waste white oil regeneration method and device, and the method comprises the following steps: S1, mixing and stirring waste white oil and a sodium hydroxide aqueous solution, and carrying out alkali washing; s2, deionized water is added into the white oil subjected to alkali washing, stirring and mixing are conducted at the normal temperature, and then a water phase is separated; S3, activated clay is added into the white oil subjected to phase separation, and stirring adsorption is conducted; and S4, filtering: cooling the white oil refined by the carclazyte, and then carrying out suction filtration while the white oil is hot to obtain regenerated white oil, and the device comprises a soft water tank, a decolorizing agent tank, a crude oil tank and other parts. Acidic substances, pigments and peculiar smells are synchronously removed through a multi-stage cooperative treatment technology of alkali washing, water washing and carclazyte refining. Compared with a step-by-step treatment or single-process regeneration method in the prior art, the method has the advantages that the defects of poor oil stability and repeated precipitation of residual impurities are overcome, and the regenerated white oil can directly meet the high-precision plastic processing requirement.

Description

Technical Field

[0001] The present invention relates to the treatment and regeneration of waste lubricants and the technical field of waste oil recovery and regeneration, and in particular to a waste white oil regeneration method and device. Background Art

[0002] White oil is a highly refined mineral oil widely used in plastics processing, cosmetics, pharmaceuticals and other fields. During the plastics processing process, white oil turns yellow and produces a pungent odor due to high-temperature oxidation and the incorporation of impurities, making it impossible to reuse directly. Currently, the regeneration process of waste white oil mostly adopts a step-by-step treatment method. The general process usually includes alkaline washing, neutralization, water washing and bleaching clay refining. Alkaline washing neutralizes the acidic components in the waste oil by adding alkaline substances such as sodium hydroxide, followed by water washing to remove suspended impurities and some polar substances. Finally, adsorbents such as activated bleaching clay are used for decolorization and deodorization. Although these processes have relatively high technical maturity in treating waste white oil and can meet certain regeneration needs, there are still many areas that need improvement in actual application.

[0003] First, the separate alkaline and water washing steps fail to effectively and simultaneously remove pigments and odors, resulting in residual impurities in the final regenerated oil, which often affects the stability of the oil. Second, many processes require higher temperatures to improve processing efficiency, which not only increases energy consumption but also leads to secondary oxidation of the oil, causing adverse changes in its color and odor. Furthermore, existing activated white clay is primarily used in a one-time manner. This high consumption increases the burden of waste liquid treatment and limits regeneration yield, making it difficult for many regenerated oil products to remain competitive in the market. Therefore, within the existing technical framework, there is an urgent need for a more efficient and environmentally friendly waste white oil regeneration technology to reduce energy consumption, lower costs, and improve product quality. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a method and device for regenerating waste white oil, which solves the problem that acidic substances, pigments and odors are difficult to remove during the regeneration process of waste white oil.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for regenerating waste white oil, comprising the following steps:

[0006] S1. Alkali washing: Mix the waste white oil with a sodium hydroxide aqueous solution and stir at 25°C-80°C for alkali washing;

[0007] S2, water washing: adding deionized water to the white oil after alkali washing, stirring and mixing at room temperature, and then performing phase separation to separate the aqueous phase;

[0008] S3. White clay refining: add activated white clay to the white oil after phase separation, and stir and adsorb at 30℃-80℃ for 1-3h;

[0009] S4. Filtration: Cool the refined white oil to 40-50°C and filter it while hot to obtain regenerated white oil.

[0010] Preferably, in step S1, the concentration of the sodium hydroxide aqueous solution is 0.5wt%-2wt%, and the mass ratio of sodium hydroxide to white oil is 1:500-1:100.

[0011] Preferably, in step S2, the amount of deionized water added is 30%-50% of the mass of the waste white oil, the stirring rate is 300-800 r / min, and the stirring time is 0.5-2 h.

[0012] Preferably, in step S3, the amount of activated clay added is 8%-12% of the mass of the waste white oil; and the stirring rate is 400-600 r / min.

[0013] Preferably, in step S4, vacuum filtration is used for filtration, and the filtration pressure is -0.08 MPa-0.1 MPa.

[0014] A waste white oil regeneration device comprises a soft water tank, the soft water tank being connected to a dissolving kettle via a pipeline, the dissolving kettle being connected to a decolorant tank via a pipeline, the decolorant tank and a crude oil tank being connected in parallel and both being connected to a decolorizing kettle via a pipeline, the decolorizing kettle outlet being connected to a washing tank via a pipeline, the washing tank being connected to a phase separation tank via a pipeline, the phase separation tank being connected to an oil phase tank via a pipeline, the oil phase tank inlet being connected to a wastewater tank via a pipeline, the oil phase tank being connected to a deodorizing kettle via a pipeline, the deodorizing kettle being connected to a filter via a pipeline, the filter being connected to a finished oil tank via a pipeline, and the soft water tank and the washing tank being connected via a pipeline.

[0015] Preferably, the decolorization kettle is equipped with a jacket heating layer with an operating temperature of 25°C-80°C; a paddle stirrer is provided inside the decolorization kettle with a rotation speed of 300-800r / min.

[0016] Preferably, the phase separation tank is provided with a transparent observation window, and an oil-water interface scale line is provided in the height direction; the diameter of the oil phase outlet pipe at the top of the phase separation tank is 1.2-1.5 times the diameter of the water phase outlet pipe at the bottom.

[0017] Preferably, an activated clay feeding bin is provided on the top of the deodorizing kettle, and the feeding amount accounts for 8%-12% of the mass of the oil phase in the kettle; and the speed of the stirrer inside the deodorizing kettle is 400-600r / min.

[0018] Preferably, the filter is a plate-and-frame structure with a filtration pressure of -0.09MPa--0.1MPa; the filter is equipped with a 200-400 mesh stainless steel filter cloth.

[0019] The present invention provides a method and device for regenerating waste white oil, which has the following beneficial effects:

[0020] 1. This invention utilizes a multi-stage, coordinated treatment process involving alkali washing, water washing, and clay refining to simultaneously remove acidic substances, pigments, and odors. Compared to existing regeneration methods that rely on separate treatments or a single process, this method overcomes the drawbacks of poor oil stability and the repeated precipitation of residual impurities. The regenerated white oil can directly meet the needs of high-precision plastic processing.

[0021] 2. This invention combines low-temperature phase separation with activated clay adsorption to keep the processing temperature below 60°C. Compared to traditional high-temperature refining processes, this not only avoids color degradation caused by secondary oxidation of the oil, but also reduces energy consumption. The regenerated white oil remains colorless and transparent after heating.

[0022] 3. This invention utilizes activated clay recycling technology to achieve adsorbent reuse. Compared to single-use adsorbents or chemical decolorization processes, this solves the industry pain points of large waste volumes and high processing costs. The yield of regenerated white oil is steadily increased, and overall costs are controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a flow chart of the method steps of the present invention;

[0024] Figure 2 Schematic diagram of the device of the present invention. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] Please see the attached Figure 1 :

[0027] Example 1:

[0028] S1, alkali washing: take 1800g of waste white oil, add 200g of deionized water solution prepared with 2.7g of NaOH (concentration 1.35wt%), and stir at 500r / min at 60℃ for 30 minutes;

[0029] S2, water washing: add 700g deionized water to the white oil after alkali washing, stir at room temperature for 1 hour, let it stand for phase separation and then separate the waste water;

[0030] S3. Clay purification: add 180 g activated clay (10 wt%) and stir at 500 rpm for 1 hour at 60°C;

[0031] S4. Filtration: The mixture was cooled to 45° C. and vacuum filtered (−0.09 MPa) to obtain 1598 g of regenerated white oil with a yield of 88.8%.

[0032] Example 2:

[0033] S1, alkali washing: waste white oil and 0.5wt% NaOH solution (mass ratio 1:500) were stirred at 25°C for 1 hour;

[0034] S2, water washing: add deionized water (40% by mass of waste white oil), stir for 0.5 hours and then separate the phases;

[0035] S3, clay refining: add 8wt% active clay, stir at 30℃ for 3 hours;

[0036] S4, the yield of regenerated white oil after filtration is 87.5%.

[0037] Example 3:

[0038] S1, alkali washing: waste white oil and 2.0wt% NaOH solution (mass ratio 1:100) were stirred at 80°C for 20 minutes;

[0039] S2, water washing: add deionized water with a mass ratio of 50% of the waste white oil, stir for 2 hours and then separate the phases;

[0040] S3, clay refining: add 12wt% activated clay, stir at 600r / min at 80℃ for 1.5 hours;

[0041] S4. Filtration: Cool to 50°C and filter under vacuum (-0.1 MPa). The yield of regenerated white oil is 89.2%.

[0042] Example 4:

[0043] S1, alkali washing: waste white oil and 1.0wt% NaOH solution (mass ratio 1:200) were stirred at 40°C for 45 minutes;

[0044] S2, water washing: add deionized water (35% by mass of waste white oil), stir for 1.5 hours and then separate the phases;

[0045] S3, clay refining: add 10wt% activated clay, stir at 450r / min at 50℃ for 2 hours;

[0046] S4, the yield of regenerated white oil after filtration is 88.6%.

[0047] Comparative Example 1:

[0048] Step S1 was omitted and clay refining was performed directly. The regenerated white oil was light yellow and still had an odor after heating. The yield was 82%.

[0049] Comparative Example 2:

[0050] When the clay refining temperature is increased to 100°C, the oxidation of the white oil intensifies, the color deepens, and the yield drops to 80%.

[0051] When the NaOH in step S1 was replaced with an equal amount of hydrochloric acid (1.35 wt %), the white oil was severely emulsified after alkali washing, phase separation was difficult, and the yield of regenerated white oil was only 65%.

[0052] Comparative Example 4:

[0053] In step S3, diatomaceous earth is used instead of activated white clay, the color of the regenerated white oil is light yellow, and there is a noticeable odor after heating, and the yield is 84%.

[0054] Comparative experiment:

[0055] Subjects:

[0056] Example 1, Example 2, Example 3, Example 4, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4;

[0057] Experimental steps:

[0058] Yield (%) measurement:

[0059] Operation process:

[0060] Initial weighing: Use an electronic balance to weigh the initial mass of the waste white oil (for example, 1800 g in Example 1) and record it as m 初始 .

[0061] Final weighing: Collect all the regenerated white oil after filtration, weigh its mass and record it as m 再生 .

[0062] Calculate the yield:

[0063]

[0064] Measurement of odor at room temperature:

[0065] Operation process:

[0066] Sample preparation: Place 50 mL of regenerated white oil in a clean glass beaker and let it stand for 10 minutes to evaporate any remaining volatile substances.

[0067] Olfactory evaluation: 3 trained testers independently performed the olfactory evaluation using the following criteria:

[0068] None: No odor, consistent with the smell of fresh white oil.

[0069] Slight odor: slightly irritating or non-oil inherent odor.

[0070] Sour / burnt smell: A distinct rancid or burnt smell.

[0071] Result determination: The final result is based on the consensus of at least two testers.

[0072] Measurement of color after heating:

[0073] Operation process:

[0074] Heating treatment: Take 50 mL of regenerated white oil in a heat-resistant test tube, place it in a constant temperature oil bath, heat to 120°C and maintain for 30 minutes.

[0075] Cooling observation: After cooling to room temperature, pour the sample into a standard colorimetric tube (25 mm in diameter) and use natural light or standard light source (D65) for visual colorimetry.

[0076] Color determination:

[0077] Colorless and transparent: The same color as deionized water, with no visible turbidity or color difference.

[0078] Pale Yellow / Light Yellow: Slightly yellowish but transparent.

[0079] Dark yellow / turbid: Distinctly yellow or opaque due to the presence of suspended matter.

[0080] Measurement of odor after heating:

[0081] Operation process:

[0082] Heat treatment: Same as color measurement steps, heat to 120℃ and maintain for 30 minutes.

[0083] Odor assessment: Cool the heated white oil to below 50°C, and have the tester smell and record the odor characteristics:

[0084] None: No odor, the smell is consistent with room temperature.

[0085] Pungent / unpleasant odor: has obvious irritation or non-inherent odor of oil.

[0086] Burnt smell: A strong smell similar to that of burning matter.

[0087] Measuring equipment and conditions

[0088] Electronic balance: precision 0.1g, used for mass weighing.

[0089] Constant temperature oil bath: temperature control accuracy ±1℃, used for heating treatment.

[0090] Standard colorimetric tube: Made of transparent glass to ensure color observation consistency.

[0091] Light source environment: natural light or standard light box (color temperature 5500K).

[0092] The above measurement data are shown in Table 1:

[0093] Table 1

[0094] sample Yield (%) Room temperature smell Color after heating Smell after heating Example 1 88.8 none Colorless and transparent none Example 2 87.5 none Colorless and transparent none Example 3 89.2 none Colorless and transparent none Example 4 88.6 none Colorless and transparent none Comparative Example 1 82.0 Slight odor light yellow Pungent Comparative Example 2 80.0 none dark yellow burnt smell Comparative Example 3 65.0 sour turbid Pungent Comparative Example 4 84.0 Slight odor light yellow Unpleasant smell

[0095] Experimental summary:

[0096] The present invention achieves efficient regeneration of waste white oil by optimizing the alkali washing, water washing, and clay refining processes. Examples 3 and 4 demonstrate the process's stability at high temperatures, high alkali concentrations, and varying clay dosages, achieving regenerated oil of comparable quality to fresh white oil. Comparative Examples 3 and 4 further demonstrate that replacing key steps or materials significantly reduces regeneration efficiency, highlighting the necessity and technical advantages of the present process.

[0097] Please see the attached Figure 2 A waste white oil regeneration device comprises a soft water tank, the soft water tank is connected to a dissolving kettle via a pipeline, the dissolving kettle is connected to a decolorant tank via a pipeline, the decolorant tank and the crude oil tank are connected in parallel and are both connected to a decolorizing kettle via a pipeline, the outlet of the decolorizing kettle is connected to a washing tank via a pipeline, the washing tank is connected to a phase separation tank via a pipeline, the phase separation tank is connected to an oil phase tank via a pipeline, the inlet of the oil phase tank is connected to a waste water tank via a pipeline, the oil phase tank is connected to a deodorizing kettle via a pipeline, the deodorizing kettle is connected to a filter via a pipeline, the filter is connected to a finished oil tank via a pipeline, and the soft water tank and the washing tank are connected via a pipeline.

[0098] The decolorization kettle is equipped with a jacketed heating layer, with an operating temperature of 25°C-80°C; a paddle stirrer is installed inside the decolorization kettle, with a rotation speed of 300-800r / min;

[0099] The phase separation tank is equipped with a transparent observation window and an oil-water interface scale line in the height direction; the diameter of the oil phase outlet pipe at the top of the phase separation tank is 1.2-1.5 times the diameter of the water phase outlet pipe at the bottom;

[0100] An activated clay feeding bin is installed on the top of the deodorizing kettle, and the feeding amount accounts for 8%-12% of the mass of the oil phase in the kettle; the speed of the agitator inside the deodorizing kettle is 400-600r / min;

[0101] The filter is a plate-and-frame structure with a filtration pressure of -0.09MPa--0.1MPa; the filter is equipped with 200-400 mesh stainless steel filter cloth.

[0102] Specifically, this device first removes waste white oil from the crude oil tank and transports it via a pipeline to a dissolving kettle. There, the waste white oil is mixed with an aqueous sodium hydroxide solution, which is supplied on demand from a soft water tank via a control valve. This thorough mixing removes the acidic substances in the waste white oil and reduces the viscosity of the mixture, paving the way for subsequent processing.

[0103] After the reaction is complete, the impure mixture is sent to a washing tank. Deionized water is added to dilute and clean the oil. Mechanical agitation ensures sufficient contact between the water and the waste white oil, promoting the removal of impurities. This process effectively removes contaminants and residues from the white oil, improving its purity.

[0104] After washing, the mixture flows into the phase separation tank, where gravity separates the oil and water phases. The clean oil phase on the upper layer flows out to the oil phase tank, while the wastewater on the lower layer is transported to the wastewater tank for subsequent treatment, ensuring efficient resource utilization and environmental protection.

[0105] The regenerated white oil from the oil phase tank is then pumped to the bleaching tank. Here, a bleaching agent is added to remove pigments and impurities from the white oil, and heating and agitation are used to achieve a thorough reaction. This process effectively improves the appearance of the finished oil, bringing it to higher market standards.

[0106] After treatment, the bleached white oil enters the deodorization vessel. During this process, an appropriate amount of activated clay is added to further remove odors and volatiles from the white oil. The agitation system in the deodorization vessel enhances contact between the activated clay and the oil, effectively improving the deodorization effect and ensuring the final product has excellent sensory properties.

[0107] After deodorization, the white oil is introduced into a filter where vacuum filtration is used to remove unreacted clay and other suspended solids through a stainless steel filter cloth. The resulting clean, regenerated white oil ensures greater transparency and quality, meeting the requirements of industrial applications.

[0108] Finally, the clean, filtered recycled white oil is transported through an outlet pipeline to a finished oil tank for storage. In the finished oil tank, the treated, high-quality recycled white oil is cooled and ready for distribution and use, ensuring the economic benefits and resource utilization of the recycling process.

[0109] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for regenerating waste white oil, characterized in that: The following steps are involved: S1. Alkali washing: Mix the waste white oil with a sodium hydroxide aqueous solution and stir at 25°C-80°C for alkali washing; S2, water washing: adding deionized water to the white oil after alkali washing, stirring and mixing at room temperature, and then performing phase separation to separate the aqueous phase; S3. White clay refining: add activated white clay to the white oil after phase separation, and stir and adsorb at 30℃-80℃ for 1-3h; S4. Filtration: Cool the refined white oil to 40-50°C and filter it while hot to obtain regenerated white oil.

2. The method for regenerating waste white oil according to claim 1, wherein: In step S1, the concentration of the sodium hydroxide aqueous solution is 0.5 wt%-2 wt%, and the mass ratio of sodium hydroxide to white oil is 1:500-1:

100.

3. The method for regenerating waste white oil according to claim 1, wherein: In step S2, the amount of deionized water added is 30%-50% of the mass of the waste white oil, the stirring rate is 300-800 r / min, and the stirring time is 0.5-2 h.

4. The method for regenerating waste white oil according to claim 1, wherein: In step S3, the amount of activated clay added is 8%-12% of the mass of the waste white oil; and the stirring rate is 400-600 r / min.

5. The method for regenerating waste white oil according to claim 1, wherein: In step S4, vacuum filtration is used for filtration, and the filtration pressure is -0.08 MPa to 0.1 MPa.

6. A waste white oil regeneration device, comprising a soft water tank according to a waste white oil regeneration method according to any one of claims 1 to 5, characterized in that: The soft water tank is connected to the dissolving kettle through a pipeline, the dissolving kettle is connected to the decolorant tank through a pipeline, the decolorant tank and the crude oil tank are connected in parallel and are both connected to the decolorizing kettle through a pipeline, the decolorizing kettle outlet is connected to the washing tank through a pipeline, the washing tank is connected to the phase separation tank through a pipeline, the phase separation tank is connected to the oil phase tank through a pipeline, the oil phase tank inlet is connected to the waste water tank through a pipeline, the oil phase tank is connected to the deodorizing kettle through a pipeline, the deodorizing kettle is connected to the filter through a pipeline, the filter is connected to the finished oil tank through a pipeline, and the soft water tank and the washing tank are connected through a pipeline.

7. The waste white oil regeneration device according to claim 6, characterized in that: The decolorization kettle is equipped with a jacket heating layer with an operating temperature of 25° C.-80° C.; a paddle stirrer is provided inside the decolorization kettle with a rotation speed of 300-800 r / min.

8. The waste white oil regeneration device according to claim 6, characterized in that: The phase separation tank is provided with a transparent observation window, and an oil-water interface scale line is provided in the height direction; the diameter of the oil phase outlet pipe at the top of the phase separation tank is 1.2-1.5 times the diameter of the water phase outlet pipe at the bottom.

9. The waste white oil regeneration device according to claim 6, characterized in that: An activated clay feeding bin is provided on the top of the deodorizing kettle, and the feeding amount accounts for 8%-12% of the mass of the oil phase in the kettle; the speed of the stirrer inside the deodorizing kettle is 400-600r / min.

10. The waste white oil regeneration device according to claim 6, characterized in that: The filter is a plate-and-frame structure with a filtration pressure of -0.09MPa--0.1MPa; the filter is equipped with a 200-400 mesh stainless steel filter cloth.

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