Method for reactivating used adsorbent, reactivation device, reactivated adsorbent, oil regenerating device having an adsorption treatment section filled with reactivated adsorbent, oil regenerating device provided with a reactivation device

Abstract

To provide a method of reactivating used adsorbent that does not require a high-temperature process, a reactivation device, reactivated adsorbent, an oil regenerating device having an adsorption treatment section filled with the reactivated adsorbent, an oil regenerating device provided with the reactivation device, the following configuration is adopted. A method of reactivating used adsorbent, a reactivation device, reactivated adsorbent, an oil regenerating device having an adsorption treatment section filled with the reactivated adsorbent, an oil regenerating device provided with the reactivation device, the method of reactivating used adsorbent includes a step of stirring the used adsorbent and a non-polar solvent, a step of separating the adsorbent and the non-polar solvent, a step of stirring the separated adsorbent and an alkali solvent, and a step of separating the adsorbent and the alkali solvent.

Description

Technical Field

[0001] This invention relates to a method for reactivating used adsorbents, a reactivation apparatus, a reactivated adsorbent, an oil regeneration apparatus having an adsorption treatment section filled with reactivated adsorbent, and an oil regeneration apparatus equipped with a reactivation apparatus. Background Technology

[0002] To protect the Earth's environment, it is necessary to reduce CO2 emissions and waste. As part of this effort, it is required to reduce the amount of used oil waste and the CO2 associated with its combustion. In achieving this, regenerating and reusing used oil is effective. For example, insulating oil in transformers and lubricating oil in compressors deteriorate over time and are usually discarded, but it is hoped that reusing these types of oils can reduce the environmental impact. Total acid number (TAN) is a widely used indicator of oil deterioration. TAN is the number of mg of potassium hydroxide required to neutralize the total acidic components in 1g of oil; the higher the TAN, the more deteriorated the oil.

[0003] In the regeneration of used oil, reducing the total acid value is effective, and mineral-based adsorbents, synthetic adsorbents, and ion exchange resins are widely used. By adding an adsorbent to the used oil and stirring, acidic components such as free fatty acids in the oil are adsorbed onto the surface and pores of the adsorbent, thereby reducing the total acid value.

[0004] Used adsorbents accumulate acidic components such as free fatty acids, resulting in reduced oil regeneration capacity compared to new products, and are therefore mostly discarded. In order to reduce the environmental impact, similar to used oil, it is desirable to restore the oil regeneration capacity of used adsorbents (hereinafter referred to as reactivation) for reuse.

[0005] The reactivation of adsorbents typically involves heat treatment. Patent Document 1 discloses a method for reactivating a zeolite adsorbent used to remove sulfur components from hydrocarbon oils. The zeolite adsorbent is heat-treated at 300°C to 800°C under an oxygen-free gas flow, followed by heat treatment at 300°C to 800°C under an oxygen-containing gas flow. This process removes impurities such as carbon and sulfide deposits accumulated on the adsorbent, thereby reactivating it.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2010-221188 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] When adsorbents are reactivated through heat treatment, the adsorbent particles tend to aggregate, reducing their specific surface area and thus the number of adsorption sites. Consequently, reactivation of the adsorbent ceases to some extent, and it may become unusable for oil regeneration. Furthermore, the high-temperature process results in high energy consumption, and compared to the case of discarded adsorbents, it may not reduce the environmental impact.

[0011] The purpose of this invention is to provide a method for reactivating used adsorbents without a high-temperature process, a reactivation apparatus, a reactivated adsorbent, an oil regeneration apparatus having an adsorption treatment section filled with reactivated adsorbent, and an oil regeneration apparatus equipped with a reactivation apparatus.

[0012] Methods for solving problems

[0013] The present invention configured to achieve the above objectives is as follows.

[0014] A method for reactivating a used adsorbent, a reactivation apparatus, a reactivated adsorbent, an oil regeneration apparatus having an adsorption treatment section filled with the reactivated adsorbent, and an oil regeneration apparatus equipped with the reactivation apparatus, wherein the method for reactivating the used adsorbent includes a step of stirring the used adsorbent and a non-polar solvent, a step of separating the adsorbent and the non-polar solvent, a step of stirring the separated adsorbent and an alkaline solvent, and a step of separating the adsorbent and the alkaline solvent.

[0015] Invention Effects

[0016] According to the present invention, a method for reactivating used adsorbent without a high-temperature process, a reactivation apparatus, a reactivated adsorbent, an oil regeneration apparatus having an adsorption treatment section filled with reactivated adsorbent, and an oil regeneration apparatus equipped with a reactivation apparatus can be provided. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the adsorbent used as the subject of this invention.

[0018] Figure 2 This is a diagram illustrating an adsorbent reactivation apparatus according to one embodiment.

[0019] Figure 3 This is a flowchart illustrating a method for reactivating an adsorbent according to one embodiment.

[0020] Figure 4 This is a graph showing the types of solvents used in the reactivation test of the adsorbent.

[0021] Figure 5 This is a graph showing the experimental results of the reactivation degree of the adsorbent obtained in the reactivation test. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following embodiments, and different embodiments can be combined with each other, and any modifications can be made within the scope that do not significantly impair the effects of the present invention.

[0023] Figure 1 This is a schematic diagram of the adsorbent used in this invention. Adsorbents are mostly roughly spherical in shape with the largest surface area, but various shapes other than spherical used adsorbents can also be used for treatment. A magnified view of a portion of the adsorbent is shown. Figure 1 The right side. The surface of the adsorbent has multiple micropores, thus increasing the surface area and improving the adsorption performance. On the other hand, for used adsorbents where oil is adsorbed into the micropores and fatty acids enter the micropores through the small cracks around the micropores, as shown in the lower right figure, the adsorption performance cannot be restored unless oil, fatty acids, etc. are removed from them. The apparatus and method for removing oil, fatty acids, etc. from used adsorbents as shown in the lower right figure will be described below.

[0024] Figure 2 This is a diagram illustrating an adsorbent reactivation apparatus 10 according to one embodiment. Additionally, Figure 3 This is a flowchart illustrating a method for reactivating an adsorbent according to one embodiment. Hereinafter, using... Figure 2 and Figure 3 This describes an apparatus and method for reactivating an adsorbent.

[0025] exist Figure 3 In step S21, the adsorbent and nonpolar solvent are introduced. Figure 2 The first processing unit (11a, also called the first processing unit) is stirred to remove oil retained on the surface and in the pores of the adsorbent. The stirring time is not limited, but it is preferable to perform the stirring for 30 minutes or more to remove oil. Known techniques such as rotating propeller-shaped stirring blades within the first processing unit (11a) can be used for stirring. To improve stirring efficiency, an ultrasonic irradiation mechanism for generating cavitation may also be provided within the first processing unit (11a) as needed.

[0026] Next, in Figure 3 In step S22, the adsorbent and nonpolar solvent are introduced. Figure 2The first filtration device (12a, also called the first filtration unit) separates the two by filtration. As a method of introducing the adsorbent and non-polar solvent into the first filtration device (12a), the mixture (slurry) of adsorbent and non-polar solvent in the first processing unit (11a) is conveyed to the first filtration device (12a) via a flow path. If necessary, a pump can also be used to shorten the time required for conveying the mixture. In the first filtration device (12a), the adsorbent and non-polar solvent are separated using a screen. The separated non-polar solvent is conveyed to a waste liquid treatment tank (not shown) via a flow path. The adsorbent separated and remaining on the screen is conveyed to the second processing unit (11b, also called the second processing unit) by a robotic arm mechanism (not shown) that holds and conveys the screen. Alternatively, the adsorbent can be vacuum-suctioned, and the suctioned adsorbent can be conveyed to the second processing unit (11b) via piping.

[0027] Next, in Figure 3 In step S23, Figure 2 In the second processing unit (11b), the adsorbent and alkaline solvent are stirred to remove acidic components such as free fatty acids accumulated on the surface and pores of the adsorbent. The stirring time is not limited, but it is preferable to perform the stirring for more than 30 minutes in order to remove oil.

[0028] Next, in Figure 3 In step S24, the adsorbent and alkaline solvent are introduced. Figure 2 The second filtration device (12b, also called the second filtration unit) separates the two by filtration. Here, a screen is used, similar to that used in the first filtration device (12a), to separate the adsorbent from the alkaline solvent. The separated alkaline solvent is then transported via a flow path to a wastewater treatment tank (not shown). Figure 3 In step S25, the separated and reactivated adsorbent remaining on the sieve is transported to... Figure 2 The adsorbent is stored in the adsorbent recovery section 13. The reactivated adsorbent can be reused for oil regeneration by filling the adsorption treatment section of the oil regeneration unit.

[0029] Figure 2 The first processing device (11a), the second processing device (11b), the first filtration device (12a), and the second filtration device (12b) are controlled by the control device 14. Figure 1 (The dashed lines in the diagram represent control). It should be noted that the first filter device (12a) and the second filter device (12b) are devices that physically separate the adsorbent and liquid components through filters, screens, etc. There are also cases where control by the control device 14 is not required. However, in cases where a mechanism (not shown) is provided to optically monitor the clogging status of the filter or screen, or where a liquid suction mechanism (not shown) is provided at the downstream end of the filter or screen to accelerate the separation, these mechanisms can also be configured to be controlled by the control device 14.

[0030] In the above embodiments, the alkaline solvent in step S23 can be changed to a mixed solvent of alkaline solvent and alcohol. Alternatively, after stirring with an alkaline solvent, stirring can be performed with an alcohol solvent.

[0031] By using alcohol, fatty acid salts accumulated on the surface and pores of the adsorbent can be removed, thus improving the reactivation effect of the adsorbent.

[0032] Furthermore, if the removal of oil from the adsorbent is insufficient in step S21, alkaline solvent and oil may remain suspended in step S23, preventing the adsorbent from being reactivated. As a preventative measure, this can also be addressed by... Figure 2 The second processing device (11b) is equipped with a mechanism 15 for measuring the suspension degree of the solvent, such as a turbidimeter. The second processing device (11b) is controlled by the control device 14 to continue stirring until the suspension degree becomes below a specified value.

[0033] The adsorbent can be composed of materials ranging from weakly basic to alkaline. The pH value of the adsorbent is preferably 7.5 to 11. The pH value can be determined, for example, by using a pH meter on pure water in which 5 wt% of the adsorbent is dispersed. Preferred types of adsorbents include silica-based, magnesium-based, silica-magnesium oxide-based (magnesium silicate-based), and mineral-based adsorbents, with silica and magnesium oxide as the main components.

[0034] The shape of the adsorbent is not particularly limited, but spherical shape is preferred. The average particle size is, for example, 10 μm or more and 2000 μm or less, more preferably 50 μm or more and 500 μm or less.

[0035] Oils that can be regenerated using adsorbents include, for example, ester oils, ether oils, vegetable oils, and mineral oils. The present invention exhibits particularly high regeneration efficiency for oils containing carbon and oxygen in their molecular structure. Specifically, this includes ester oils, vegetable oils, and ether oils.

[0036] The non-polar solvent used in the first processing unit (11a) may be, for example, hexane, toluene, cyclohexane, benzene, or a mixture of two or more of them.

[0037] The alkaline solvent used in the second processing device (11b) is preferably an alkaline solvent with a higher alkalinity than the adsorbent that is being processed. For example, aqueous solutions of sodium hydroxide, potassium hydroxide, and calcium hydroxide, or a mixture of two or more of them, can be used.

[0038] The alcohol solvent used in the second processing unit (11b) may be methanol, ethanol, propanol, butanol, or a mixture of two or more of them.

[0039] The mixed solvent of alkali and alcohol used in the second processing device (11b) can be a solvent made by mixing two or more of the above solvents.

[0040] illustrate Figure 2 and Figure 3 The reason why the apparatus and method shown are effective for the reactivation of adsorbents is that acidic components such as free fatty acids accumulate on the surface and in the pores of adsorbents used for oil regeneration. Therefore, the adsorption sites of the adsorbent are reduced, making it difficult to reuse it for oil regeneration. Thus, effective reactivation of the adsorbent involves removing the deposits on the adsorption sites.

[0041] The inventors conducted numerous reactivation experiments on used adsorbents and found that multi-stage treatment using various solvents could remove deposits on adsorption sites and was effective in reactivating the adsorbents.

[0042] Specifically, as the first stage of solvent treatment, stirring the adsorbent in a non-polar solvent removes oil from the surface and pores of the adsorbent. Furthermore, as the second stage of solvent treatment, it was confirmed that stirring the adsorbent in an alkaline solvent removes acidic components such as free fatty acids accumulated at the adsorption sites and restores the surface pH of the adsorbent to alkalinity. In this case, the alkalinity of the alkaline solvent is preferably higher than the surface pH of the adsorbent. Furthermore, it was determined that using an alcohol solvent, which is a polar solvent, in the second stage of solvent treatment removes fatty acid salts. It was clarified that through this multi-stage treatment, the adsorbent can be reactivated.

[0043] Furthermore, as described in the examples below, it was confirmed that the adsorbent could not be sufficiently reactivated in single-stage treatments using nonpolar solvents, alkaline solvents, etc. In particular, in aqueous systems with alkaline solvents, the reactivation became insufficient due to the oil suspension within the adsorbent.

[0044] Patent Document 1 discloses a method for reactivating adsorbents through heat treatment. However, when using a previously used adsorbent as the subject of this invention, the adsorbent particles become aggregated, reducing the specific surface area of ​​the adsorbent. Consequently, the number of adsorption sites decreases, resulting in insufficient reactivation of the adsorbent and sometimes rendering it unusable for oil regeneration. Furthermore, the energy consumption of heat treatment is high, thus sometimes failing to reduce environmental impact.

[0045] To address this issue, the multi-stage treatment using various solvents in this invention enables effective reactivation of the adsorbent without requiring high-temperature processes, thus contributing to energy conservation.

[0046] The configuration of the reactivation apparatus of the present invention can be easily confirmed through visual inspection, apparatus disassembly, etc. The type of solvent used can be easily confirmed through chemical analysis such as infrared spectrophotometry, gas chromatography-mass spectrometry, etc.

[0047] The following shows the results of the reactivation test of the adsorbent to verify the effectiveness of the reactivation device 10.

[0048] In the studies of Examples 1 to 5 and Comparative Examples 1 to 6, a silica-magnesium oxide adsorbent was used as a representative example of the adsorbent. In this experiment, a silica-magnesium oxide adsorbent that had previously been used in the regeneration treatment of the ester oil was used. The average particle size of the silica-magnesium oxide adsorbent before the ester oil regeneration treatment was 150 μm, and the pH value was 9.1.

[0049] Solvent types are shown Figure 4 The primary solvent is the solvent used in the first processing unit (11a), and the secondary solvent is the solvent used in the second processing unit (11b).

[0050] In Examples 1 to 4, the primary solvent used was hexane or toluene, and the secondary solvent used was a 1M aqueous sodium hydroxide solution or a mixture of a 1M aqueous sodium hydroxide solution and ethanol.

[0051] The primary solvent and adsorbent are introduced into the first processing unit (11a) and stirred at 1000 rpm for 30 minutes. Then, the primary solvent and adsorbent are separated by vacuum filtration using the filtration device (12a). Next, the secondary solvent and adsorbent are introduced into the second processing unit (11b) and stirred at 1000 rpm for 30 minutes. Then, the secondary solvent and adsorbent are separated by vacuum filtration using the filtration device (12b). Finally, the adsorbent is recovered using the adsorbent recovery unit 13.

[0052] In Example 5, hexane was used as the primary solvent, and 1M sodium hydroxide aqueous solution and ethanol were used as the secondary solvent. Hexane and the adsorbent were introduced into the first processing unit (11a) and stirred at 1000 rpm for 30 minutes. Then, the primary solvent and adsorbent were separated by suction filtration using the first filtration unit (12a). Next, the 1M sodium hydroxide aqueous solution and the adsorbent were introduced into the second processing unit (11b) and stirred at 1000 rpm for 15 minutes. Then, ethanol was added to the second processing unit (11b) and stirred at 1000 rpm for 15 minutes. Then, the secondary solvent and adsorbent were separated by suction filtration using the second filtration unit (12b). Finally, the adsorbent was recovered using the adsorbent recovery unit 13.

[0053] In Comparative Example 1, as a comparison with the Examples, no solvent treatment of the adsorbent was performed. In Comparative Examples 2 to 6, any one of water, hexane, acetone, ethanol, and 1M sodium hydroxide aqueous solution was used as the primary solvent. The primary solvent and adsorbent were introduced into the first processing apparatus (11a) and stirred at a stirring speed of 1000 rpm for 30 minutes. Then, the primary solvent and adsorbent were separated by suction filtration using the first filtration apparatus (12a). Without using a secondary solvent, a single-stage solvent treatment was performed, and the adsorbent was recovered using the adsorbent recovery unit 13.

[0054] The reactivation effect of the adsorbents in Examples 1 to 5 and Comparative Examples 1 to 6 was confirmed as follows. Deteriorated ester oil with a total acid value of 9 mg KOH / g was added to the adsorption treatment section filled with each adsorbent, and the mixture was stirred at 1000 rpm for 30 minutes. Then, the adsorbent and ester oil were separated by vacuum filtration, and the ester oil was recovered. The reactivation degree of each adsorbent was evaluated using the following formula.

[0055] Reactivation degree = (total acid value reduction based on reactivated adsorbent) / (total acid value reduction based on virgin adsorbent) 100

[0056] Here, the total acid value reduction based on the new adsorbent refers to the total acid value reduction (mg KOH / g) of the degraded ester oil based on the new silica-magnesium oxide adsorbent, and the total acid value reduction based on the reactivated adsorbent refers to the total acid value reduction (mg KOH / g) of the degraded ester oil based on the silica-magnesium oxide adsorbent treated in the examples or comparative examples.

[0057] The reactivation degrees of Examples 1 to 5 and Comparative Examples 1 to 6 based on adsorbent-based reactivation tests are shown in the figure. Figure 5 In Comparative Example 1, the reactivation degree was as low as 18%, indicating that the reactivation effect of the adsorbent was low. In addition, even with single solvent treatment in Comparative Examples 2 to 6, the reactivation degree was less than 50%, and a sufficient reactivation effect could not be obtained.

[0058] On the other hand, in Examples 1 and 2, the degree of reactivation exceeded 80%. Furthermore, in Examples 3 to 5, which used alcohol in a secondary solvent, the degree of reactivation was over 100%, confirming that the oil regeneration capacity was higher than that of the new adsorbent.

[0059] The results of the reactivation test described above confirm that the used adsorbent can be reactivated and reused for oil regeneration by using a multi-stage solvent treatment device 10 that uses a non-polar solvent as the primary solvent and an alkaline solvent or alcohol as the secondary solvent.

[0060] Therefore, by utilizing a multi-stage process with various solvents, it is possible to provide an apparatus and method for reactivating used adsorbents without high-temperature processes, reactivated adsorbents, an oil regeneration apparatus having an adsorption treatment section filled with reactivated adsorbents, and an oil regeneration apparatus equipped with such a reactivation apparatus. This reduces the amount of waste oil and adsorbent, and also reduces CO2 emissions from waste incineration, thus achieving a reduction in environmental impact.

[0061] Explanation of reference numerals in the attached figures

[0062] 10…reactivation device, 11a…first processing device, 11b…second processing device, 12a…first filtration device, 12b…second filtration device, 13…adsorbent recovery unit.

Claims

1. A method for reactivating a used adsorbent, characterized in that, include: The step of stirring the used adsorbent and non-polar solvent. The step of separating the adsorbent and the nonpolar solvent. The step of stirring the separated adsorbent and alkaline solvent, and The step of separating the adsorbent and the alkaline solvent.

2. The method for reactivating used adsorbent according to claim 1, characterized in that, In the step of stirring the separated adsorbent and the alkaline solvent, a mixture formed by adding an alcohol solvent to the alkaline solvent is used.

3. The method for reactivating used adsorbent according to claim 1, characterized in that, After stirring the separated adsorbent and alkaline solvent, a step of stirring the adsorbent and alcohol solvent is performed.

4. The method for reactivating used adsorbent according to claim 1, characterized in that, The adsorbent is an adsorbent with silicon dioxide and magnesium oxide as its main components.

5. The method for reactivating used adsorbent according to claim 1, characterized in that, The nonpolar solvent comprises at least one of hexane, toluene, cyclohexane, and benzene.

6. The method for reactivating used adsorbent according to claim 1, characterized in that, The alkaline solvent comprises at least one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, and calcium hydroxide aqueous solution.

7. The method for reactivating used adsorbent according to claim 2, characterized in that, The alcohol solvent includes at least one of methanol, ethanol, propanol, and butanol.

8. The method for reactivating used adsorbent according to claim 1, characterized in that, The molecular structure of the oil adsorbed by the used adsorbent contains carbon and oxygen.

9. The method for reactivating used adsorbent according to claim 1, characterized in that, Of the oils adsorbed by the used adsorbent, ester oil and vegetable oil are either the base oils.

10. The method for reactivating used adsorbent according to claim 1, characterized in that, The used adsorbent is mainly roughly spherical in shape.

11. The method for reactivating used adsorbent according to claim 1, characterized in that, The pH value of the adsorbent is 7.5~11.

12. A device for reactivating used adsorbent, characterized in that, have: A first processing apparatus for stirring used adsorbent and non-polar solvent. A first filtration device separates the mixture within the first processing unit into the adsorbent and liquid components. A second processing device for stirring the adsorbent and alkaline solvent separated by the first filtration device, and A second filtration device that separates the mixture in the second processing unit into the adsorbent and liquid components.

13. The reactivation apparatus for used adsorbent according to claim 12, characterized in that, In the second processing device, the adsorbent separated by the first filtration device and the mixture of alkaline solvent and alcohol solvent are stirred.

14. The reactivation apparatus for used adsorbent according to claim 12 or 13, characterized in that, It is equipped with a turbidimeter for measuring the suspension degree of the solvent in the second processing device.

15. An adsorbent, characterized in that, The adsorbent was reactivated using the reactivation method described in any one of claims 1 to 11.

16. An oil regeneration device, characterized in that, It has an adsorption treatment section. The adsorption treatment section is filled with an adsorbent that has been reactivated by the reactivation method of the used adsorbent according to any one of claims 1 to 11.

17. An oil regeneration device, characterized in that, A device for reactivating used adsorbent as described in claim 12 or 13.

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