Reactivation method for used adsorbent, reactivation device for used adsorbent, reactivated adsorbent, oil regeneration device including adsorption processing portion packed with reactivated adsorbent, oil regeneration device equipped with reactivation device

Abstract

To provide a reactivation method and a reactivation device each for used adsorbent and requiring no high temperature process, a reactivated adsorbent, an oil regeneration device including adsorption processing portion packed with reactivated adsorbent, and an oil regeneration device equipped with a reactivation device.SOLUTION: There is provided a reactivation method for a used adsorbent, the method comprising the steps of; stirring the used adsorbent and a nonpolar solvent; separating the adsorbent from the nonpolar solvent; stirring the separated adsorbent and an alkali solvent; and separating the adsorbent from the alkali solvent. There are also provided: a reactivation device; a reactivated adsorbent; an oil regeneration device including an adsorption processing portion packed with a reactivated adsorbent; and an oil regeneration device equipped with a reactivation device.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for reactivating a used adsorbent, a reactivation device, a reactivated adsorbent, an oil regeneration device having an adsorption treatment section filled with the reactivated adsorbent, and an oil regeneration device equipped with a reactivation device. [Background technology]

[0002] To protect the global environment, it is necessary to reduce CO2 emissions and waste. As part of this effort, there is a need to reduce the amount of used oil discarded and the CO2 emissions associated with its incineration. An effective way to achieve this is to restore the functions of used oil and reuse it. For example, insulating oil in transformers and lubricating oil in compressors deteriorate over time and are usually discarded, but reusing these types of oil is expected to reduce the environmental impact. The total acid number is widely used as an indicator of oil deterioration. The total acid number is the number of milligrams of potassium hydroxide required to neutralize all acidic components contained in 1 gram of oil; the higher the value, the more deteriorated the oil is.

[0003] Reducing the total acid number is an effective way to regenerate used oil, and adsorbents such as mineral adsorbents, synthetic adsorbents, and ion exchange resins are widely used. By adding an adsorbent to used oil and stirring it, acidic components such as free fatty acids in the oil are adsorbed onto the surface and pores of the adsorbent, reducing the total acid number.

[0004] Used adsorbents are often discarded because they accumulate acidic components such as free fatty acids, reducing their oil regeneration capacity compared to new ones. To reduce the environmental impact, it is desirable to restore the oil regeneration capacity of used adsorbents (hereafter referred to as reactivation) and reuse them, just like used oil.

[0005] Heat treatment is commonly used to reactivate adsorbents. Patent Document 1 discloses a method for reactivating a zeolite adsorbent that removes sulfur from hydrocarbon oils. The zeolite adsorbent is heat-treated at 300°C to 800°C in an oxygen-free air stream, and then heat-treated at 300°C to 800°C in an oxygen-containing air stream, thereby removing impurities such as carbon and sulfides that have accumulated on the adsorbent and reactivating the adsorbent. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-221188 Summary of the Invention [Problem to be solved by the invention]

[0007] When reactivating adsorbents by heat treatment, the particles of the adsorbent aggregate during the heat treatment, reducing the specific surface area and the number of adsorption sites. This means that the reactivation of the adsorbent stops at a certain level and it may not be possible to reuse it for oil recovery. In addition, the high-temperature process requires high energy consumption, and the environmental impact may not be reduced compared to disposing of the adsorbent.

[0008] An object of the present invention is to provide a method for reactivating a used adsorbent without the need for a high-temperature process, a reactivation device, a reactivated adsorbent, an oil regeneration device having an adsorption treatment section filled with the reactivated adsorbent, and an oil regeneration device equipped with a reactivation device. [Means for solving the problem]

[0009] The present invention has the following configuration to achieve the above object. A method for reactivating used adsorbent, including the steps of stirring the used adsorbent and a non-polar solvent, separating the adsorbent from the non-polar solvent, stirring the separated adsorbent and an alkaline solvent, and separating the adsorbent from the alkaline solvent; a reactivation device; a reactivated adsorbent; an oil regeneration device having an adsorption treatment section filled with the reactivated adsorbent; and an oil regeneration device equipped with a reactivation device. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a method for reactivating a used adsorbent without the need for a high-temperature process, a reactivation device, a reactivated adsorbent, an oil regeneration device having an adsorption treatment section filled with the reactivated adsorbent, and an oil regeneration device equipped with a reactivation device. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a used adsorbent to which the present invention is directed. [Figure 2] FIG. 1 illustrates an embodiment of an adsorbent reactivation device. [Figure 3] 1 is a flow chart illustrating an embodiment of a method for reactivating an adsorbent. [Figure 4] FIG. 1 shows the solvent types used in the adsorbent reactivation test. [Figure 5] FIG. 1 is a diagram showing experimental results of the reactivation degree of the adsorbent obtained in a reactivation test. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments, and different embodiments may be combined with each other, and any modifications may be made within the scope that does not significantly impair the effects of the present invention.

[0013] Figure 1 is a schematic diagram of the adsorbent targeted by this invention. Adsorbents are often roughly spherical, which has the largest surface area, but used adsorbents of various shapes other than spherical shapes can also be treated. A partial enlargement of the adsorbent is shown on the right side of Figure 1. The surface of the adsorbent has numerous pores, which increases the surface area and improves adsorption performance. However, if oil is adsorbed into these pores and fatty acids are trapped in the fine cracks around the pores, the adsorption performance will not be restored unless the oil, fatty acids, etc. are removed from the used adsorbent, as shown in the lower right figure. Below, we will explain the device and method for removing oil, fatty acids, etc. from used adsorbent, as shown in the lower right figure.

[0014] Fig. 2 is a diagram showing an adsorbent reactivation apparatus 10 according to one embodiment. Fig. 3 is a flowchart showing an adsorbent reactivation method according to one embodiment. The adsorbent reactivation apparatus and method will be described below with reference to Figs. 2 and 3.

[0015] In step S21 of FIG. 3, the adsorbent and nonpolar solvent are introduced into the treatment device 1 (11a, also referred to as the first treatment device) of FIG. 2 and stirred to remove oil retained on the surface and in the pores of the adsorbent. There is no limit to the stirring time, but it is desirable to carry out the stirring for 30 minutes or more to remove the oil. For stirring, well-known techniques such as rotating a propeller-shaped stirring blade inside the treatment device 1 (11a) can be applied. To improve stirring efficiency, an ultrasonic irradiation mechanism for generating cavitation inside the treatment device 1 (11a) may be provided as needed.

[0016] Next, in step S22 of FIG. 3, the adsorbent and nonpolar solvent are introduced into filtration device 1 (12a, also referred to as the first filtration device) of FIG. 2, where they are separated by filtration. To introduce the adsorbent and nonpolar solvent into filtration device 1 (12a), a mixture (slurry) of the adsorbent and nonpolar solvent in processing device 1 (11a) is transported to filtration device 1 (12a) via a flow path. If necessary, a pump may be used to shorten the time required to transport the mixture. In filtration device 1 (12a), the adsorbent and nonpolar solvent are separated using a mesh. The separated nonpolar solvent is transported to a waste liquid treatment tank (not shown) via a flow path. The separated adsorbent remaining on the mesh is transported to processing device 2 (11b, also referred to as the second processing device) by a hand mechanism (not shown) that grips and transports the mesh. Alternatively, the adsorbent may be vacuum-suctioned and transported to processing device 2 (11b) via a pipe.

[0017] Next, in step S23 of Fig. 3, the adsorbent and alkaline solvent are stirred in treatment device 2 (11b) of Fig. 2 to remove acidic components such as free fatty acids that have accumulated on the surface and in the pores of the adsorbent. There is no limit to the stirring time, but it is desirable to carry out the stirring for 30 minutes or more to remove oil.

[0018] Next, in step S24 of FIG. 3, the adsorbent and alkaline solvent are introduced into filtration device 2 (12b, also referred to as the second filtration device) of FIG. 2, where they are separated by filtration. Here, as with filtration device 1 (12a), the adsorbent and alkaline solvent are separated using a mesh. The separated alkaline solvent is transported to a waste liquid treatment tank (not shown) via a flow path. The separated, reactivated adsorbent remaining on the mesh is transported to the adsorbent recovery section 13 of FIG. 2 in step S25 of FIG. 3 and stored. The reactivated adsorbent can be reused for oil regeneration by filling it into the adsorption treatment section of the oil regeneration device.

[0019] The processing device 1 (11a), processing device 2 (11b), filtration device 1 (12a), and filtration device 2 (12b) in Figure 2 are controlled by a control device 14 (the dashed lines in Figure 1 indicate the control). Note that filtration device 1 (12a) and filtration device 2 (12b) are devices that physically separate the adsorbent and the liquid component using a filter, mesh, or the like, and there are cases where control by the control device 14 is not necessary. However, if a mechanism (not shown) is provided to optically monitor the clogging state of the filter or mesh, or if a suction mechanism (not shown) is provided to suck the liquid from the downstream of the filter or mesh to accelerate separation, the control device 14 can be configured to control these mechanisms.

[0020] In the above embodiment, the alkaline solvent in step S23 may be changed to a mixed solvent of an alkaline solvent and an alcohol, or the stirring treatment may be performed in an alkaline solvent, followed by stirring treatment in an alcohol solvent.

[0021] By using alcohol, fatty acid salts deposited on the surface and in the pores of the adsorbent can be removed, thereby improving the effect of reactivating the adsorbent.

[0022] Furthermore, if the removal of oil from the adsorbent in step S21 is insufficient, the alkaline solvent and oil may become suspended in step S23, making it impossible to reactivate the adsorbent. As a preventative measure, the treatment device 2 (11b) in Figure 2 may be equipped with a mechanism 15 for measuring the turbidity of the solvent, such as a turbidimeter, and the control device 14 may control the treatment device 2 (11b) to continue stirring until the turbidity becomes equal to or less than a predetermined value.

[0023] Adsorbents made of weakly basic to basic materials can be used. The pH value of the adsorbent is preferably 7.5 to 11. The pH value can be measured, for example, by using a pH meter to disperse the adsorbent at 5 wt% in pure water. Preferred types of adsorbents include silica-based, magnesium-based, silica-magnesia-based (magnesium silicate-based) adsorbents whose main components are silica and magnesium oxide, and mineral-based adsorbents.

[0024] The shape of the adsorbent is not particularly limited, but is preferably spherical. The average particle size is, for example, from 10 μm to 2000 μm, more preferably from 50 μm to 500 μm.

[0025] Examples of oils that can be regenerated using the adsorbent include ester oils, ether oils, vegetable oils, and mineral oils. The regeneration effect of the present invention is particularly high for oils that contain carbon and oxygen in their molecular structure. Specifically, these oils include ester oils, vegetable oils, and ether oils.

[0026] The non-polar solvent used in the treatment device 1 (11a) may be, for example, hexane, toluene, cyclohexane, benzene, or a mixture of two or more of these.

[0027] The alkaline solvent used in the treatment device 2 (11b) is preferably more basic than the adsorbent to be treated. For example, an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, an aqueous solution of calcium hydroxide, or a mixture of two or more of these can be used.

[0028] The alcohol solvent used in the treatment device 2 (11b) may be methanol, ethanol, propanol, butanol, or a mixture of two or more of these.

[0029] The mixed solvent of alkali and alcohol used in the treatment device 2 (11b) may be a mixture of two or more of the above-mentioned solvents.

[0030] The reason why the device and method shown in Figures 2 and 3 are effective for reactivating adsorbents is explained below. Acidic components such as free fatty acids accumulate on the surface and pores of adsorbents used for oil reclamation. This reduces the adsorption sites of the adsorbent, making it difficult to reuse it for oil reclamation. Therefore, removing the deposits from the adsorption sites is effective for reactivating adsorbents.

[0031] The inventors conducted numerous reactivation tests on used adsorbents and found that multi-stage treatment using multiple solvents can remove deposits from adsorption sites and is effective in reactivating adsorbents. Specifically, in the first stage of solvent treatment, agitating the adsorbent in a nonpolar solvent can remove oil from the surface and pores of the adsorbent. Furthermore, in the second stage of solvent treatment, agitating the adsorbent in an alkaline solvent can remove acidic components such as free fatty acids deposited on the adsorption sites and restore the surface pH of the adsorbent to basicity. In this case, the alkaline solvent preferably has a higher basicity than the surface pH of the adsorbent. Furthermore, they found that fatty acid salts can be removed by using a polar alcohol solvent in the second stage of solvent treatment. It was revealed that such multi-stage treatment can reactivate adsorbents.

[0032] Furthermore, as will be described later in the Examples, it was confirmed that the adsorbent could not be sufficiently reactivated by a single-stage treatment using a non-polar solvent, an alkaline solvent, etc. In particular, it was confirmed that aqueous solutions such as alkaline solvents were insufficient in reactivation because they were suspended in the oil retained in the adsorbent.

[0033] Patent Document 1 discloses the reactivation of adsorbents by heat treatment. However, when this method is applied to the used adsorbents targeted by the present invention, the adsorbent particles aggregate, reducing the specific surface area of ​​the adsorbent. This reduces the number of adsorption sites, resulting in insufficient reactivation of the adsorbent and making it impossible to reuse it for oil recovery. Furthermore, heat treatment consumes a lot of energy, so it may not be effective in reducing environmental impact.

[0034] To address these issues, the multi-stage treatment using multiple solvents of the present invention can effectively reactivate the adsorbent and contributes to energy savings because it does not require a high-temperature process.

[0035] The configuration of the reactivation device according to the present invention can be easily confirmed by visual inspection or by disassembling the device, etc. The type of solvent used can be easily confirmed by chemical analysis such as infrared spectroscopy or gas chromatography mass spectrometry.

[0036] Below, we present the results of verifying the effectiveness of the reactivation device 10 through adsorbent reactivation tests. In the studies of Examples 1 to 5 and Comparative Examples 1 to 6, a silica-magnesia adsorbent was used as a representative example of the adsorbent. In these tests, the silica-magnesia adsorbent used had previously been used in the regeneration treatment of ester oil. Before the regeneration treatment of ester oil, the silica-magnesia adsorbent had an average particle size of 150 μm and a pH value of 9.1.

[0037] The solvent types are shown in Figure 4. The primary solvent is the solvent used in treatment device 1 (11a), and the secondary solvent is the solvent used in treatment device 2 (11b).

[0038] In Examples 1 to 4, hexane or toluene was used as the primary solvent, and a 1M aqueous sodium hydroxide solution or a mixture of 1M aqueous sodium hydroxide and ethanol was used as the secondary solvent. The primary solvent and adsorbent were introduced into treatment device 1 (11a) and stirred at a stirring speed of 1000 rpm for 30 minutes. The primary solvent and adsorbent were then separated by suction filtration in filtration device (12a). Next, the secondary solvent and adsorbent were introduced into treatment device 2 (11b) and stirred at a stirring speed of 1000 rpm for 30 minutes. The secondary solvent and adsorbent were then separated by suction filtration in filtration device (12b). The adsorbent was then recovered in adsorbent recovery section 13.

[0039] In Example 5, hexane was used as the primary solvent, and 1M aqueous sodium hydroxide and ethanol were used as the secondary solvent. Hexane and the adsorbent were introduced into treatment device 1 (11a) and stirred at a stirring speed of 1000 rpm for 30 minutes. The primary solvent and the adsorbent were then separated by suction filtration in filtration device 1 (12a). Next, the 1M aqueous sodium hydroxide and the adsorbent were introduced into treatment device 2 (11b) and stirred at a stirring speed of 1000 rpm for 15 minutes. Furthermore, ethanol was added to treatment device 2 (11b) and stirred at a stirring speed of 1000 rpm for 15 minutes. The secondary solvent and the adsorbent were then separated by suction filtration in filtration device 2 (12b). The adsorbent was then recovered in adsorbent recovery section 13.

[0040] In Comparative Example 1, for comparison with the Examples, solvent treatment of the adsorbent was not performed. In Comparative Examples 2 to 6, water, hexane, acetone, ethanol, or 1 M aqueous sodium hydroxide solution was used as the primary solvent. The primary solvent and adsorbent were introduced into treatment device 1 (11a) and stirred at a stirring speed of 1000 rpm for 30 minutes. Thereafter, the primary solvent and adsorbent were separated by suction filtration in filtration device 1 (12a). A single-stage solvent treatment was performed without using a secondary solvent, and the adsorbent was recovered in adsorbent recovery section 13.

[0041] The reactivation effect of the adsorbents in Examples 1 to 5 and Comparative Examples 1 to 6 was confirmed as follows. Degraded ester oil with a total acid value of 9 mgKOH / g was placed in an adsorption treatment unit filled with each adsorbent and stirred at a stirring speed of 1000 rpm for 30 minutes. The adsorbent and ester oil were then separated by suction filtration, and the ester oil was recovered. The reactivation degree of each adsorbent was evaluated using the following formula. Reactivation degree = (total acid number reduction value by reactivated adsorbent) / (total acid number reduction value by new adsorbent) * 100 Here, the total acid number reduction by a new adsorbent is the amount (mg KOH / g) of reduction in the total acid number of a deteriorated ester oil by a new silica-magnesia-based adsorbent, and the total acid number reduction by a reactivated adsorbent is the amount (mg KOH / g) of reduction in the total acid number of a deteriorated ester oil by a silica-magnesia-based adsorbent treated in an example or comparative example.

[0042] The reactivation degrees of Examples 1 to 5 and Comparative Examples 1 to 6 obtained by adsorbent reactivation tests are shown in Figure 5. In Comparative Example 1, the reactivation degree was as low as 18%, indicating a low reactivation effect for the adsorbent. Furthermore, even in Comparative Examples 2 to 6 where treatment was performed with a single solvent, the reactivation degree was 50% or less, indicating that a sufficient reactivation effect was not obtained.

[0043] On the other hand, the reactivation degree exceeded 80% in Examples 1 and 2. Furthermore, in Examples 3 to 5, in which alcohol was used in combination as a secondary solvent, the reactivation degree exceeded 100%, confirming that the oil regeneration ability was higher than that of a new adsorbent.

[0044] The results of the reactivation test described above confirmed that multi-stage solvent treatment using the reactivation device 10, which uses a non-polar solvent as the primary solvent and an alkaline solvent or alcohol as the secondary solvent, can reactivate used adsorbents and enable them to be reused for oil recovery.

[0045] Therefore, we can provide an apparatus and method for reactivating used adsorbents without the need for high-temperature processes through multi-stage treatment with multiple solvents, a reactivated adsorbent, an oil regeneration apparatus having an adsorption treatment section filled with the reactivated adsorbent, and an oil regeneration apparatus equipped with such a reactivation apparatus. This can reduce the amount of oil and adsorbent waste and also reduce CO2 emissions during the waste incineration process, thereby reducing the environmental load. [Explanation of symbols]

[0046] 10...reactivation device, 11a...treatment device 1, 11b...treatment device 2, 12a...filtration device 1, 12b...filtration device 2, 13...adsorbent recovery section.

Claims

1. agitating the spent adsorbent and the non-polar solvent; separating the adsorbent and the non-polar solvent; agitating the separated adsorbent and alkaline solvent; separating the adsorbent and the alkaline solvent; A method for reactivating a used adsorbent, comprising:

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

3. 2. The method for reactivating a used adsorbent according to claim 1, After the step of stirring the separated adsorbent and the alkaline solvent, A method for reactivating a used adsorbent, comprising the step of stirring the adsorbent and an alcohol solvent.

4. 2. The method for reactivating a used adsorbent according to claim 1, A method for reactivating a used adsorbent, wherein the adsorbent is an adsorbent containing silica and magnesium oxide as main components.

5. 2. The method for reactivating a used adsorbent according to claim 1, A method for reactivating a used adsorbent, characterized in that the non-polar solvent contains at least one of hexane, toluene, cyclohexane, and benzene.

6. 2. The method for reactivating a used adsorbent according to claim 1, A method for reactivating a used adsorbent, wherein the alkaline solvent contains at least one of an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, and an aqueous solution of calcium hydroxide.

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

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

9. 2. The method for reactivating a used adsorbent according to claim 1, A method for reactivating a used adsorbent, characterized in that the oil adsorbed by the used adsorbent is based on either ester oil or vegetable oil.

10. 2. The method for reactivating a used adsorbent according to claim 1, A method for reactivating a used adsorbent, characterized in that the shape of the used adsorbent is mainly approximately spherical.

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

12. a first treatment device for agitating the used adsorbent and the non-polar solvent; a first filtration device that separates the mixture in the first treatment device into the adsorbent and a liquid component; a second treatment device that stirs the adsorbent and the alkaline solvent separated in the first filtration device; a second filtration device that separates the mixture in the second treatment device into the adsorbent and a liquid component; A reactivation device for used adsorbent, comprising:

13. 13. The apparatus for reactivating spent adsorbent according to claim 12, A reactivation apparatus for a used adsorbent, characterized in that in the second treatment apparatus, the adsorbent separated in the first filtration apparatus and a mixed liquid of an alkaline solvent and an alcohol solvent are stirred.

14. 14. The apparatus for reactivating a used adsorbent according to claim 12 or 13, 10. A reactivation apparatus for a used adsorbent, comprising a turbidity meter for measuring the turbidity of the solvent in the second treatment apparatus.

15. An adsorbent reactivated by the method for reactivating a used adsorbent according to any one of claims 1 to 11.

16. An oil regeneration device characterized by having an adsorption treatment unit filled with an adsorbent reactivated by the method for reactivating a used adsorbent according to any one of claims 1 to 11.

17. An oil regeneration device comprising the device for reactivating a used adsorbent according to claim 12 or 13.

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