Extraction device

Abstract

To improve the extraction efficiency of liquid-liquid extraction methods using slug flow. [Solution] The extraction apparatus 1 disclosed herein comprises a first channel 10 for transporting a first liquid L1 which is an aqueous liquid, a second channel 20 for transporting a second liquid L2 which is a hydrophobic non-aqueous liquid, a confluence section 30 to which the first channel 10 and the second channel 20 are connected and which generates a slug flow in which the first liquid L1 and the second liquid L2 flow alternately in the flow direction, and an outlet channel 40 which is a pipe located downstream of the confluence section 30 and transports the slug flow along the axial direction. The extraction apparatus then adds fine bubbles F to at least one of the first liquid L1 and the second liquid L2 contained in the slug flow. B It is further equipped with a microbubble introduction mechanism 50 that incorporates a slug flow. This improves the extraction efficiency of liquid-liquid extraction methods using slug flow.

Description

Technical Field

[0001] The technology disclosed herein relates to an extraction apparatus. Specifically, the technology disclosed herein relates to an extraction apparatus used in a liquid-liquid extraction method utilizing a slug flow.

Background Art

[0002] The liquid-liquid extraction method is used in various fields as a method for extracting a desired extraction target. In this liquid-liquid extraction method, two types of immiscible liquids (for example, an aqueous liquid and a non-aqueous liquid) are dispersed. Thereby, the extraction target contained in one liquid can be transferred to the other liquid. As an example of this liquid-liquid extraction method, an emulsion method may be cited (see Patent Document 1 and Non-Patent Document 1). In this emulsion method, the two liquids are dispersed until an emulsion state (emulsified state) is achieved. As this increases the area of the liquid interface between the two liquids, high extraction efficiency can be realized.

[0003] However, it is difficult for the emulsified liquid generated by the emulsion method to separate back into the two liquids. Therefore, in recent years, a liquid-liquid extraction method utilizing a slug flow (hereinafter referred to as the "slug method") has been investigated (see Patent Document 2 and Non-Patent Document 2). In this slug method, a slug flow in which an aqueous liquid and a non-aqueous liquid flow alternately in the axial direction of a pipe is formed. In this slug flow, transfer of the extraction target occurs at the liquid interface between the aqueous liquid and the non-aqueous liquid. Further, since the slug method does not highly disperse the two liquids, the two liquids after the extraction treatment can be easily separated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0005] [Non-Patent Document 1] Ting-Fan Feng et al, Intensification of High-phase-ratio extraction via microbubble-agitation in gas-liquid-liquid systems,Chemical Engineering Science,177,(2018),270-283 [Non-Patent Document 2] Nora Assmann et al,Extraction inmicrorectors: Intensification by adding an inert gas phase,Chemical Engineering and Processing,50,(2011),822-827 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in slug flow, the surface area of ​​the liquid interface between the aqueous and non-aqueous liquids is smaller than in emulsified liquids. Therefore, in the slug method, it takes a long time to sufficiently extract the desired target material. The technology disclosed herein was developed in consideration of this problem and aims to improve the extraction efficiency of liquid-liquid extraction methods using slug flow. [Means for solving the problem]

[0007] To solve the above-mentioned problems, an extraction device with the following configuration is proposed.

[0008] The extraction apparatus disclosed herein comprises a first channel for transporting a first liquid, which is an aqueous liquid; a second channel for transporting a second liquid, which is a hydrophobic non-aqueous liquid; a confluence section to which the first and second channels are connected, generating a slug flow in which the first and second liquids flow alternately in the flow direction; and an outlet channel, which is a pipe located downstream of the confluence section and transports the slug flow along its axial direction. Furthermore, the extraction apparatus is characterized by comprising a microbubble introduction mechanism for incorporating fine bubbles into either the first liquid or the second liquid contained in the slug flow.

[0009] As a result of various experiments and studies, the inventors discovered that by including fine bubbles in either the first liquid or the second liquid contained in the slug flow, a superior extraction efficiency compared to conventional methods can be achieved. The extraction apparatus disclosed herein is based on this finding. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic cross-sectional view showing an extraction apparatus according to the first embodiment. [Figure 2] Figure 2 is a cross-sectional view illustrating the slug flow generated in the extraction apparatus according to the first embodiment. [Figure 3] Figure 3 is a schematic cross-sectional view showing an extraction apparatus according to the second embodiment. [Figure 4] Figure 4 is a cross-sectional view illustrating the slug flow generated in the extraction apparatus according to the second embodiment. [Figure 5] Figure 5 is a graph showing the evaluation results of the extraction efficiency in the first test. [Figure 6] Figure 6 is a graph showing the evaluation results of the extraction efficiency in the second test. [Modes for carrying out the invention]

[0011] An embodiment of the technology disclosed herein will be described below. Matters not specifically mentioned herein but necessary for carrying out the disclosed technology (e.g., the preparation procedure for the first and second liquids) can be understood as design matters for those skilled in the art based on the prior art. The disclosed technology can be carried out based on the content disclosed herein and common technical knowledge in the art. The drawings are schematic, and the dimensional relationships (length, width, thickness, etc.) shown in the drawings do not reflect actual dimensional relationships.

[0012] <First Embodiment> The following describes a first embodiment of the extraction apparatus disclosed herein. Figure 1 is a schematic cross-sectional view of the extraction apparatus according to the first embodiment. Figure 2 is a cross-sectional view illustrating the slug flow generated in the extraction apparatus according to the first embodiment. In the following description, the left side in Figures 1 and 2 is referred to as the upstream direction in the flow direction, and the right side as the downstream direction. However, the installation direction of the equipment is not limited to the technology disclosed herein.

[0013] The extraction apparatus 1 according to this embodiment is used for liquid-liquid extraction (slag method) utilizing slag flow. As shown in Figure 1, this extraction apparatus 1 comprises a first flow path 10, a second flow path 20, a confluence section 30, an outlet flow path 40, and a microbubble introduction mechanism 50. Furthermore, the extraction apparatus 1 according to this embodiment includes a separation section 60. Each component will be described below.

[0014] (1) First channel 10 The first channel 10 is a channel for transferring the first liquid L1, which is an aqueous liquid. In this specification, "aqueous liquid" is a broad concept that includes hydrophilic liquids. An example of this aqueous liquid is water (such as deionized water, distilled water, or pure water). Another example of an aqueous liquid is a hydrophilic organic solvent. Examples of hydrophilic organic solvents include lower alcohols. Specific examples of lower alcohols include methanol, ethanol, 2-propanol, ethylene glycol, and glycerin. The aqueous liquid may also be a mixture of a hydrophilic organic solvent and water. Furthermore, the aqueous liquid may contain conventionally known additives that can be used in liquid-liquid extraction. For example, the aqueous liquid may contain a scavenger that captures the target of extraction. Another example of an additive is a surfactant.

[0015] As shown in Figure 1, the first flow path 10 in this embodiment comprises a first tank 12, a first transfer pipe 14, and a first pump 16. The first tank 12 is a tank for storing the first liquid L1. The first transfer pipe 14 connects the first tank 12 to the junction 30. Specifically, the upstream end 14a of the first transfer pipe 14 is connected to the first tank 12. On the other hand, the downstream end 14b of the first transfer pipe 14 is connected to the first inflow passage 32 (see Figure 2) of the junction 30. The first pump 16 is a transfer means for transferring the first liquid L1 in the first tank 12 to the junction 30. In this embodiment, the first flow path 10 uses a syringe pump as the first pump 16. This syringe pump pressurizes the inside of the first tank 12 to pump the first liquid L1 to the junction 30. However, the structure of the first pump is not particularly limited, and any conventionally known pump can be used without any particular restrictions. For example, the first pump may be a diaphragm pump, a piezo micropump, etc. Note that the first pump 16 is not an essential component in the first flow path 10. Specifically, if a pressurized tank is used as the first tank 12, the first liquid L1 can be transferred even without providing the first pump.

[0016] Furthermore, the first flow path 10 may be equipped with conventionally known equipment that can be used for transferring the solution, as long as it does not significantly impair the effectiveness of the technology disclosed herein. For example, a check valve, pressure gauge, flow meter, filter media, etc., may be attached to the first transfer pipe 14. Although not limited to the technology disclosed herein and therefore not shown in the figures, a pipe for supplying cleaning solution (cleaning pipe) may be connected to the first transfer pipe 14. In this case, it is preferable to provide a T-switching valve at the connection between the first transfer pipe 14 and the cleaning pipe. This allows the inside of the first transfer pipe 14 to be cleaned after each use.

[0017] (2) Second channel 20 The second channel 20 is a channel for transporting the second liquid L2, which is a hydrophobic non-aqueous liquid. In this specification, "non-aqueous liquid" refers to a hydrophobic liquid that does not mix with the aqueous liquid described above. Examples of non-aqueous liquids, without limiting the technology disclosed herein, include aliphatic hydrocarbons, aromatic hydrocarbons, higher alcohols, ethers, methane halides, and ketones. Examples of aliphatic hydrocarbons include N-pentane, N-hexane, cyclohexane, N-heptane, N-nonane, N-octane, N-decane, N-undecane, N-dodecane, tridecane, tetradecane, kerosene, petroleum hydrocarbons, naphtha, dipentene, and turpentine oil. Examples of aromatic hydrocarbons include benzene, toluene, and xylene. Examples of higher alcohols include 1-octanol, dodecanol, hexadecanol, and oleic alcohol. Examples of ethers include diethyl ether and diphenyl ether. Examples of halide methanes include chloroform, carbon tetrachloride, and dichloromethane. Examples of ketones include acetone, methyl ethyl ketone, and cyclohexanone.

[0018] The second flow path 20 in the first embodiment has a structure substantially the same as that of the first flow path 10 described above. Specifically, the second flow path 20 comprises a second tank 22, a second transfer pipe 24, and a second pump 26. The second tank 22 is a tank for storing the second liquid L2. The second transfer pipe 24 connects the second tank 22 to the junction 30. Specifically, the upstream end 24a of the second transfer pipe 24 is connected to the second tank 22. On the other hand, the downstream end 24b of the second transfer pipe 24 is connected to the second inflow passage 34 (see Figure 2) of the junction 30. The second pump 26 is a transfer means for transferring the second liquid L2 in the second tank 22 to the junction 30. The second pump 26 is also a syringe pump, similar to the first pump 16. However, the second pump can also be any conventionally known pump without any particular limitations. Furthermore, similar to the first channel 10, the second channel 20 may also be equipped with conventionally known equipment that can be used for transferring the solution, as long as it does not significantly impair the effectiveness of the technology disclosed herein. Descriptions of this equipment are omitted to avoid repetition. Also, similar to the first transfer pipe 14, it is preferable that a washing pipe is attached to the second transfer pipe 24.

[0019] Furthermore, the extraction apparatus disclosed herein transfers the substance to be extracted, contained in one of the first liquid and the second liquid, to the other liquid. Here, the substance to be extracted is not particularly limited as long as it is soluble in both the first and second liquids and can be extracted by liquid-liquid extraction. For example, the extraction apparatus disclosed herein can be used for the extraction of organic compounds such as phenol, ions of metal elements such as gold, platinum, palladium, nickel, lithium, and cobalt, and polymer compounds such as proteins and polysaccharides. Among these, when metal ions are to be extracted, it is preferable to add a scavenger to the liquid to be extracted. In the first embodiment, the case in which the substance to be extracted is transferred from the second liquid L2 (non-aqueous liquid) to the first liquid L1 (aqueous liquid) will be described as an example. That is, in this embodiment, the substance to be extracted is stored in the second tank 22 together with the second liquid L2.

[0020] (3) Confluence section 30 The confluence section 30 is the part where the first flow path 10 and the second flow path 20 are connected. This confluence section 30 generates a slug flow in which the first liquid L1 and the second liquid L2 flow alternately in the flow direction. As shown in Figure 2, the confluence section 30 in this embodiment includes a first inlet passage 32, a second inlet passage 34, a connecting section 36, and an outlet passage 38. The first inlet passage 32 is a flow path that communicates with the first flow path 10 (first transfer pipe 14). The second inlet passage 34 is a flow path that communicates with the second flow path 20 (second transfer pipe 24). The connecting section 36 is the part where the first inlet passage 32 and the second inlet passage 34 are connected. The outlet passage 38 is a flow path provided downstream of the connecting section 36.

[0021] In the junction 30 of the above configuration, the first liquid L1 flows from the first flow path 10 into the first inflow passage 32. Also, the second liquid L2 flows from the second flow path 20 into the second inflow passage 34. The first liquid L1 and the second liquid L2 then merge at the connection 36. Here, the first liquid L1 and the second liquid L2 are liquids that do not dissolve in each other. Therefore, in the outflow passage 38 downstream of the connection 36, a two-phase flow (slug flow) is generated in which the first liquid L1 and the second liquid L2 flow alternately in the flow direction.

[0022] (4) Outlet channel 40 The outlet channel 40 is a pipe located downstream of the confluence section 30. The slug flow described above is transported along the axial direction of the outlet channel 40. Specifically, the upstream end 40a of the outlet channel 40 is connected to the outflow channel 38 of the confluence section 30. The downstream end 40b of the outlet channel 40 is connected to the separation section 60. The slug flow that flows out from the outflow channel 38 of the confluence section 30 is transported through the liquid channel 40c within the outlet channel 40 to the separation section 60. During transport, the liquid interface L S The target to be extracted moves from the second liquid L2 to the first liquid L1 via this process.

[0023] Furthermore, the inner circumferential wall 40d of the outlet channel 40 is made of fine bubbles F, which will be described later. BIt is preferable that the supply is made of a material with good wettability to the liquid to be supplied (first liquid L1 in this embodiment). For example, if the inner circumferential wall 40d of the outlet channel 40 has excellent wettability to the first liquid L1, a thin liquid phase consisting of the first liquid L1 is formed between the inner circumferential wall 40d of the outlet channel 40 and the second liquid L2. That is, improving the wettability between the inner circumferential wall 40d and the first liquid L1 causes the first liquid L1 to become a continuous phase along the inner circumferential wall 40d. At this time, the second liquid L2 becomes a droplet in which the entire surface is covered by the first liquid L1. As a result, the liquid interface L between the first liquid L1 and the second liquid L2 S The area of ​​becomes larger. And the liquid interface L surrounding the second liquid L2 S Fine bubble F in the vicinity B Because convection occurs, it can further contribute to improving extraction efficiency. Furthermore, according to this embodiment, fine bubbles F are preferentially introduced into the first liquid L1. B It will become easier to supply.

[0024] Furthermore, the diameter D (pipe diameter) of the outlet channel 40 is preferably 0.1 mm or more, more preferably 0.25 mm or more, even more preferably 0.5 mm or more, and particularly preferably 0.75 mm or more. This increases the flow rate of the outlet channel 40, which contributes to improving extraction efficiency. On the other hand, the diameter D of the outlet channel 40 is preferably 6 mm or less, more preferably 5 mm or less, even more preferably 4 mm or less, and particularly preferably 3 mm or less. By keeping the diameter D of the outlet channel 40 below a certain level, it becomes easier to maintain a state in which the first liquid L1 and the second liquid L2 are transported as a slug flow.

[0025] (5) Microbubble introduction mechanism 50 In the first embodiment, the extraction apparatus 1 adds fine bubbles F to the first liquid L1 contained in the slag flow. B It is equipped with a microbubble introduction mechanism 50 that incorporates slug flow. Experiments have confirmed that this improves the extraction efficiency of the liquid-liquid extraction method using slug flow. Although it is not intended to limit the technology disclosed herein, it is presumed that this improvement in extraction efficiency is achieved by the following mechanism. As described above, in the slug flow during transport, the liquid interface LS The extraction target moves from the second liquid L2 to the first liquid L1 via the intermediate. As the movement of the extraction target proceeds, the liquid interface L of the second liquid L2 S While the concentration of the extraction target decreases in the vicinity, the concentration of the extraction target at the liquid interface L of the first liquid L1 S The concentration of the extraction target increases in the vicinity. Then, at the liquid interface L S As the concentration difference of the extraction target between the two liquids sandwiching the interface decreases, the movement of the extraction target from the second liquid L2 to the first liquid L1 becomes less likely to occur. However, in the central portion of the second liquid L2 (the liquid interface L S At a position distant from the interface), a high concentration of the extraction target still exists. Similarly, in the central portion of the first liquid L1 (the liquid interface L S At a position distant from the interface), the extraction target is hardly contained. Therefore, in the extraction apparatus 1 according to the present embodiment, fine bubbles F are added to the liquid contained in the slug flow (here, the first liquid L1) B to supply. These fine bubbles F B In the liquid to which the fine bubbles are supplied (the first liquid L1), convection occurs in the vicinity of the liquid interface L with the other liquid S This causes convection in the vicinity. As a result, at the liquid interface L S Since the concentration difference of the extraction target between the two liquids sandwiching the interface increases again, the movement of the extraction target from the second liquid L2 to the first liquid L1 can be promoted. In addition, the fine bubbles F B At the liquid interface L with the other liquid S When adsorbed, a part of the other liquid (here, the second liquid L2) may cover the surface of the fine bubbles F B This may occur. In this case, the fine bubbles F B It is also assumed that the second liquid L2 covering the fine bubbles separates into the liquid of the first liquid L1. As a result, the area of the interface between the first liquid L1 and the second liquid L2 increases. As a result, the extraction efficiency from the second liquid L2 to the first liquid L1 is improved. By these actions, even when the slug method, which tends to reduce the area of the liquid interface L between the first liquid L1 and the second liquid L2 S is adopted, high extraction efficiency can be achieved.

[0026] Note that the term "fine bubbles F" in the present specification B"Fine bubbles" are defined as bubbles with a diameter of 100 μm or less, similar to the general definition of fine bubbles. By dispersing such fine bubbles, more favorable convection can be generated within each of the first liquid L1 and the second liquid L2. Also, large bubbles can form at the liquid interface L S If it adheres to the surface, the contact area between the first liquid L1 and the second liquid L2 will decrease, which may actually reduce the extraction efficiency. From this perspective, fine bubbles F B The average bubble diameter is more preferably 80 μm or less, even more preferably 60 μm or less, and particularly preferably 40 μm or less. On the other hand, fine bubbles F with extremely small bubble diameters are also preferred. B (Nanobubbles) are not broken down unless subjected to special treatment such as ultrasonic treatment, and therefore may hinder separation in the separation section 60 described later. From this perspective, fine bubbles F B The average bubble diameter is preferably 10 μm or more, and particularly preferably 20 μm or more.

[0027] Furthermore, in order to more effectively demonstrate the extraction efficiency improvement effect of the technology disclosed herein, the diameter D of the outlet channel 40 (i.e., the liquid phase diameter of the first liquid L1 and the second liquid L2) and the fine bubble F B It is preferable to control the relationship with the average bubble diameter. For example, when the diameter D of the outlet channel 40 is 100%, the fine bubble F B The ratio of average bubble diameters is preferably 10% or less, more preferably 8% or less, even more preferably 6% or less, and particularly preferably 4% or less. On the other hand, the lower limit of the ratio of bubble diameters is preferably 0.5% or more, more preferably 1.0% or more, and particularly preferably 1.5% or more.

[0028] Next, the specific configuration of the microbubble introduction mechanism 50 in this embodiment will be described. The microbubble introduction mechanism 50 in this embodiment comprises a bubble generating tube 52 and a gas supply means 54. The bubble generating tube 52 is a cylindrical porous body having a liquid channel 52a with both ends open. On the other hand, the gas supply means 54 supplies gas from the outer peripheral wall 52b of the bubble generating tube 52 toward the liquid channel 52a, and introduces fine bubbles F into the first liquid L1 flowing through the liquid channel 52a. BThe following is introduced. Specifically, the liquid channel 52a of the bubble generation tube 52 is in communication with the liquid channel 40c of the outlet channel 40. That is, the slug flow flowing through the outlet channel 40 flows into the liquid channel 52a of the bubble generation tube 52. Multiple micropores of the micro-order (preferably 3 μm or less, more preferably 1 μm or less) are formed in this bubble generation tube 52. These micropores are in communication from the outer circumferential wall 52b to the inner circumferential wall 52c of the bubble generation tube 52. Therefore, when high-pressure gas is supplied to the outer circumferential wall 52b of the bubble generation tube 52, the gas permeates the bubble generation tube 52 and enters the liquid channel 52a. The gas then forms fine bubbles F into the slug flow (first liquid L1) in the liquid channel 52a. B It is supplied in the form of fine bubbles F. Also, similar to the outlet channel 40 described above, the inner circumferential wall 52c of the bubble generating tube 52 is also supplied with fine bubbles F. B It is preferable that the material is made of a material with high wettability to the liquid to be supplied (in this case, the first liquid L1). This allows fine bubbles F to be supplied to the first liquid L1. B It can be supplied more efficiently.

[0029] As shown in Figure 2, the bubble generating tube 52 in this embodiment is housed in a cylindrical sealed container called a housing 53. This housing 53 includes a gas introduction pipe 53a connected to a gas supply means 54 described later, and an internal cavity 53b that houses the bubble generating tube 52. By housing the bubble generating tube 52 inside the housing 53, it becomes easier to maintain a high pressure of the gas supplied to the outer peripheral wall 52b of the bubble generating tube 52. Also, as shown in Figure 2, it is preferable that the diameter of the internal cavity 53b of the housing 53 is larger than the diameter of the bubble generating tube 52. This creates an annular gap S between the housing 53 and the bubble generating tube 52. By supplying gas to this gap S, high-pressure gas can be supplied over the entire circumference of the outer peripheral wall 52b of the bubble generating tube 52.

[0030] Furthermore, as shown in Figure 1, the gas supply means 54 in this embodiment includes a gas supply source 54a, a pressure adjustment unit 54b, and a valve 54c. The gas supply source 54a is filled with gas supplied to the bubble generation pipe 52. BThe gas used to generate the fine bubbles F is not limited to a specific gas and can be appropriately changed considering the components of the materials (first liquid L1, second liquid L2, and the material to be extracted) supplied to the extraction device 1. Examples of such gases include air, oxygen gas, carbon dioxide gas, nitrogen gas, and argon gas. Next, the pressure adjustment unit 54b adjusts the pressure of the gas supplied from the gas supply source 54a to a preset pressure. This generates fine bubbles F in the bubble generation tube 52. B This allows for stable generation of gas. Furthermore, the valve 54c is configured to be opened and closed as needed. Although not shown in the figures, the gas supply means 54 may also be equipped with other conventionally known equipment that can be used for supplying gas. For example, the gas supply means 54 may be equipped with a pressure gauge, a flow meter, a regulator, and the like.

[0031] As shown in Figures 1 and 2, the microbubble introduction mechanism 50 in this embodiment is attached to the outlet channel 40. This introduces fine bubbles F into the liquid (slag flow including the first liquid L1 and the second liquid L2) flowing through the outlet channel 40. B This allows for the supply of fine bubbles F to the slug flow. This can result in the following advantages: First, fine bubbles F can be supplied to the slug flow. B When supplied, the liquid interface L between the first liquid L1 and the second liquid L2 S Fine bubble F B This is introduced. This results in the liquid interface L S Because the generation of convection in the vicinity is promoted, the movement of the extractable substance from the second liquid L2 to the first liquid L1 can be promoted. Next, in the first channel 10 and the second channel 20, it is necessary to set the fine bubble supply conditions considering the length of the other channel, the pipe diameter, the liquid flow rate and pressure, etc. On the other hand, in the outlet channel 40 after the first channel 10 and the second channel 20 have been integrated, the fine bubble supply conditions can be set uniformly. Next, in the outlet channel 40, since a slug flow has already been formed, the movement of the extractable substance from the second liquid L2 to the first liquid L1 has progressed to some extent. In this state, fine bubbles F BBy generating convection through the supply of liquid, the movement of the extractable material from the second liquid L2 to the first liquid L1 can be further promoted. In addition, since a slug flow is formed in the outlet channel 40, a large shear force is applied to the interface between the inner circumferential wall 52c of the bubble generation tube 52 and the fluid. As a result, the gas that has permeated the bubble generation tube 52 and entered the liquid channel 52a is finely chopped, allowing for the efficient generation of fine bubbles.

[0032] (6) Separation part 60 Next, in the extraction apparatus 1 according to this embodiment, a separation unit 60 is provided downstream of the outlet channel 40 to separate the slug flow into a first liquid L1 and a second liquid L2. This separation unit 60 comprises a separation tank 62, a first recovery tank 64, and a second recovery tank 66. The separation tank 62 is a tank located downstream of the outlet channel 40. The dispersion liquid discharged from the outlet channel 40 is stored in this separation tank 62. Here, the dispersion liquid discharged from the outlet channel 40 is a slug flow in which the first liquid L1 and the second liquid L2 flow alternately. Therefore, the dispersion liquid discharged into the separation tank 62 separates easily with just a short period of standing. As a result, the separation tank 62 stores a two-layer separation liquid in which the first liquid L1 is present in the lower layer and the second liquid L2 is present in the upper layer. The first liquid L1, which contains the object to be extracted, is recovered in the first recovery tank 64. On the other hand, the second liquid L2 is recovered in the second recovery tank 66. Thus, because the extraction apparatus 1 according to this embodiment uses the slag method, the dispersion after the extraction process can be easily separated.

[0033] The extraction apparatus 1 according to the first embodiment has been described above. In this extraction apparatus 1, a slug flow containing a first liquid L1 and a second liquid L2 is generated in the outlet channel 40. Fine bubbles F are then introduced into the first liquid L1 within this slug flow. B This is introduced. This will create a liquid interface L between the first liquid L1 and the second liquid L2. S Liquid-liquid extraction is facilitated through this process. Therefore, according to the extraction apparatus 1 of the first embodiment, the extraction efficiency of the liquid-liquid extraction method using slug flow can be improved.

[0034] <Second Embodiment> As described above, in the first embodiment, fine bubbles F are formed in the outlet channel 40 after the slug flow is generated. B They are supplying it. However, in the technology disclosed herein, fine bubbles F are added to the first liquid L1 (or second liquid L2) contained in the slag flow. B It is sufficient if it contains fine bubbles F in the first channel 10 and the second channel 20 before the slug flow is generated. B It may also be supplied. Below, an example of an extraction apparatus having such a configuration, the extraction apparatus 1A according to the second embodiment will be described.

[0035] Figure 3 is a schematic cross-sectional view showing the extraction apparatus according to the second embodiment. Figure 4 is a cross-sectional view illustrating the slug flow generated in the extraction apparatus according to the second embodiment. As shown in Figure 3, the microbubble introduction mechanism 50A of the extraction apparatus 1A according to the second embodiment introduces fine bubbles F into the first channel 10A B It is configured to supply [the substance]. Below, the microbubble introduction mechanism 50A and the first channel 10A of the extraction apparatus 1A according to the second embodiment will be described. Note that other components (second channel 20, confluence section 30, outlet channel 40, separation section 60) can be configured to be the same as those of the first embodiment, so redundant explanations will be omitted.

[0036] As shown in Figure 3, in the second embodiment, the bubble generating tube 52A is located in the first transfer tube 14 of the first flow path 10. This allows fine bubbles F to be generated in the first liquid L1 in the first flow path 10. B This is supplied. This first liquid L1 is fine bubble F B It is supplied to the confluence section 30 containing the fine bubbles F. B A slug flow is generated in which the first liquid L1 and the second liquid L2, which contain F, flow alternately (see Figure 4). In such a slug flow, fine bubbles F are already present. B Because it contains this, immediately after it flows out from the confluence 30, the liquid interface L of the two liquids S Liquid-liquid extraction is facilitated through this process. Therefore, according to the second embodiment, the extraction efficiency of the liquid-liquid extraction method using slug flow can be suitably improved.

[0037] Furthermore, the first flow path 10A in the second embodiment includes a first tank 12, a first transfer pipe 14, and a first pump 16, similar to the first embodiment. The first tank 12 is a tank for storing the first liquid L1. The first transfer pipe 14 connects the first tank 12 to the junction 30. These configurations are substantially the same as those in the first embodiment. In addition, the first pump 16 in the second embodiment is located on the first transfer pipe 14. In the second embodiment, the first pump 16 can be a liquid pump or the like. Furthermore, the first flow path 10A in this embodiment further includes a retention section 17 and a return pipe 18. The retention section 17 is a container for temporarily storing the first liquid L1 before it is transferred to the junction 30. The return pipe 18 is a pipe connecting the retention section 17 to the first tank 12. In other words, the first flow path 10A in the second embodiment has a circulation line including a first tank 12, a bubble generating pipe 52A, and a retention section 17. With this configuration, fine bubbles F are introduced into the first liquid L1 circulating in the first flow path 10A. B This allows for the supply of an appropriate amount of fine bubbles F. B The first liquid L1 containing the above can be stably supplied to the merging section 30.

[0038] <Other Embodiments> Preferred embodiments of the technology disclosed herein have been described above. However, the extraction apparatus disclosed herein is not limited to the configurations shown in the first and second embodiments described above, and various configurations can be modified.

[0039] For example, in the first and second embodiments described above, liquid-liquid extraction is performed from the second liquid L2 (non-aqueous liquid) to the first liquid L1 (aqueous liquid). However, the extraction apparatus disclosed herein can also be used for liquid-liquid extraction from the first liquid L1 to the second liquid L2. That is, the target to be extracted before the extraction process may be contained in the first liquid L1, not the second liquid L2. Even in this case, fine bubbles F are added to one of the liquids in the slug flow. B By supplying the liquid interface L S This can facilitate liquid-liquid extraction.

[0040] Furthermore, in the first and second embodiments described above, fine bubbles F are introduced into the first liquid L1, which is the destination of the object to be extracted. B It supplies fine bubbles. B The liquid interface L may also be supplied to the source of the object to be extracted (i.e., the liquid containing the object to be extracted before the extraction process). S Liquid-liquid extraction can be promoted via this. Furthermore, fine bubbles F B The fine bubbles F may be supplied to both the first liquid L1 and the second liquid L2. In other words, the technology disclosed herein provides a fine bubble F to at least one of the first liquid L1 and the second liquid L2. B It is sufficient to supply the fine bubbles F to both the first liquid L1 and the second liquid L2. B When supplied, the liquid interface L of the first liquid L1 and the second liquid L2 S Because convection occurs in the vicinity of the first liquid L1 and the second liquid L2, liquid-liquid extraction can be performed more efficiently. Also, in Figures 2 and 4, fine bubbles F B The fine bubbles F remain in the receiving liquid (first liquid L1 in these drawings). However, such illustrations are not intended to limit the technology disclosed herein. That is, the fine bubbles F supplied to one of the liquids remain in the receiving liquid. B The liquid interface L S It is also possible that the liquid may move beyond the first liquid L1 and the second liquid L2 to the other liquid. In this case as well, the liquid interface L of the first liquid L1 and the second liquid L2 S Because convection occurs in the vicinity, extraction efficiency may be improved.

[0041] Furthermore, in the first and second embodiments, fine bubbles F are introduced into the piping (first transfer pipe 14, outlet channel 40) that transfers the liquid. B It supplies fine bubbles. B The supply destination is not limited to piping. For example, fine bubble F B The gas may be supplied to tanks that store liquid (first tank 12, second tank 22, etc.). In this case, a porous body having fine pores is submerged in the liquid in the tank, and the gas is supplied to the porous body. This allows fine bubbles to be supplied to the liquid stored in the tank.

[0042] [Example Test] The following describes test examples relating to the technology disclosed herein. However, the following test examples are not intended to limit the scope of the technology disclosed herein.

[0043] A. First test 1. Sample preparation In this experiment, extraction experiments were conducted using extraction apparatus 1, which has the configuration shown in Figure 1. The detailed test conditions are as follows. First, in this experiment, water (purified water) was used as the first liquid L1. On the other hand, dodecane was used as the second liquid L2. In addition, phenol (concentration: 1.0 × 10) was added to the second liquid L2 as the target of extraction. -4 (g / ml) was added. Next, in this test, the diameter of the outlet channel 40 was set to 1 mm and the length of the channel to 1 m. The pumping speed from the first channel 10 and the second channel 20 was set so that the liquid flow rate in the outlet channel 40 was 10 ml / min. The liquid that passed through the outlet channel 40 was then discharged to the separation section 60.

[0044] In this experiment, we attempted liquid-liquid extraction of phenol from the second liquid L2 to the first liquid L1 while supplying gas (atmosphere) from the gas supply means 54 to the bubble generating tube 52. The lower layer of the liquid discharged to the separation unit 60 (first liquid L1) was collected as an analytical sample. Here, in this experiment, fine bubbles F were supplied to the bubble generating tube 52. B Three different samples were prepared with varying supply volumes (gas supply pressure). Specifically, the gas supply pressure in Sample 1 was 0 MPa (fine bubble F). B The gas supply was set to "no supply". In addition, the gas supply pressure in Sample 2 was set to 0.1 MPa. And in Sample 3, the gas supply pressure was set to 0.13 MPa.

[0045] 2. Evaluation of extraction efficiency In this test, the mass transfer capacity coefficient Ka was measured. The procedure for measuring the mass transfer capacity coefficient Ka is as follows. First, a sample solution was collected from the first liquid L1 in the separation unit 60, and the phenol concentration C (g / ml) immediately after collection of the recovered solution was measured using a UV-Vis spectrophotometer (model: UV-1600) manufactured by Shimadzu Corporation. Next, the equilibrium phenol concentration C0 (g / ml) of the discharged solution was obtained by measuring the phenol concentration after stirring the discharged solution (first liquid L1 in the separation unit 60) for one day. Then, the extraction rate E (%) was calculated based on the following equation (1). Next, the mass transfer capacity coefficient Ka was calculated based on the following equation (2). Note that "E" in equation (2) represents the extraction rate (%), and "E * " is the equilibrium extraction rate (%), "t" is the residence time (s), and "C1" is the initial concentration. In this study, the mass transfer coefficient Ka was evaluated as the extraction efficiency of phenol. The results are shown in Figure 5.

[0046]

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[0047]

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[0048] As shown in Figure 5, samples 2 and 3 showed a significant increase in the mass transfer coefficient Ka compared to sample 1. This indicates that supplying fine bubbles to the first liquid (non-aqueous liquid) in the slag flow can improve the extraction efficiency in the slag method.

[0049] B. Second Examination In this experiment, extraction experiments were conducted using extraction apparatus 1A with the configuration shown in Figure 3. In this experiment, fine bubbles F were used. B Phenol extraction was performed under the same conditions as the first test, except that the supply location was changed to the first flow path 10 (first transfer pipe 14). As shown in Table 2 below, the gas supply pressure in sample 4 was 0 MPa (fine bubble F BThe setting was changed to (no gas supply). In addition, the gas supply pressure in sample 5 was set to 0.1 MPa. In this test as well, the mass transfer capacity coefficient Ka of samples 4 and 5 was measured. The measurement results are shown in Figure 6.

[0050] As shown in Figure 6, a significant increase in the mass transfer capacity coefficient Ka was also observed in sample 5. This indicates that the supply destination of fine bubbles is not limited to the outlet channel after slug flow generation, but can also be the first channel before slug flow generation.

[0051] The technologies disclosed herein have been described in detail above, but these are merely illustrative examples and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. In other words, the technologies disclosed herein encompass the forms described in items 1 to 6 below.

[0052] <Item 1> A first channel for transporting a first liquid, which is an aqueous liquid, A second channel for transporting a second liquid, which is a hydrophobic, non-aqueous liquid, The first flow path and the second flow path are connected, and a junction is provided that generates a slug flow in which the first liquid and the second liquid flow alternately in the flow direction, The piping is located downstream of the aforementioned confluence and has an outlet channel that transports the slug flow along its axial direction. Equipped with, An extraction apparatus further comprising a microbubble introduction mechanism for introducing fine bubbles into at least one of the first liquid and the second liquid contained in the slug flow.

[0053] <Item 2> The aforementioned microbubble introduction mechanism is A bubble generating tube is a cylindrical porous body having liquid channels with open ends, A gas supply means that supplies gas from the outer circumference of the bubble generating tube toward the liquid flow path and introduces the fine bubbles into the first liquid or the second liquid flowing through the liquid flow path. The extraction device described in item 1, which is equipped with the following features.

[0054] <Item 3> The extraction apparatus according to item 1 or 2, wherein the microbubble introduction mechanism introduces the fine bubbles into the first liquid or the second liquid in any of the first channel, the second channel, and the outlet channel.

[0055] <Item 4> The extraction apparatus according to any one of items 1 to 3, wherein a separation unit for separating the slug flow into a first liquid and a second liquid is provided downstream of the outlet flow path.

[0056] <Item 5> An extraction apparatus according to any one of items 1 to 4, wherein the average bubble diameter of the fine bubbles is 20 μm to 60 μm.

[0057] <Item 6> An extraction apparatus according to any one of items 1 to 5, wherein, when the diameter of the outlet channel is set to 100%, the average bubble diameter of the fine bubbles is 1.5% to 4%. [Explanation of Symbols]

[0058] 1 Extraction device 10 First channel 12 Tank No. 1 14 1st transfer pipe 16. Pump No. 1 17 Retention part 18 Piping 20 Second channel 22 Tank No. 2 24 2nd transfer pipe 26. Pump No. 2 30 Confluence 32 1st inflow channel 34 Second inflow channel 36 Connection part 38 Outflow channel 40 Outlet channel 50 Microbubble Introduction Mechanism 52 Bubble generating tube 53 cabinets 54 Gas supply means 60 Separation section 62 Separation tanks 64. First Recovery Tank 66 Second Recovery Tank F B Fine bubbles L1 1st liquid L2 2nd liquid L S liquid interface

Claims

1. A first channel for transporting a first liquid, which is an aqueous liquid, A second channel for transporting a second liquid, which is a hydrophobic, non-aqueous liquid, The first flow path and the second flow path are connected, and a junction is provided where the first liquid and the second liquid flow alternately in the flow direction to generate a slug flow, The piping is located downstream of the aforementioned confluence and has an outlet channel that transports the slug flow along its axial direction. Equipped with, An extraction apparatus further comprising a microbubble introduction mechanism for introducing fine bubbles into at least one of the first liquid and the second liquid contained in the slug flow.

2. The aforementioned microbubble introduction mechanism is A bubble generating tube is a cylindrical porous body having liquid channels with open ends, A gas supply means that supplies gas from the outer wall of the bubble generating tube toward the liquid flow path and introduces the fine bubbles into the first liquid or the second liquid flowing through the liquid flow path. The extraction apparatus according to claim 1, comprising:

3. The extraction apparatus according to claim 1, wherein the fine bubble introduction mechanism introduces the fine bubbles into the first liquid or the second liquid in any of the first channel, the second channel, and the outlet channel.

4. The extraction apparatus according to claim 1, wherein a separation unit is provided downstream of the outlet channel for separating the slug flow into a first liquid and a second liquid.

5. The extraction apparatus according to claim 1, wherein the average bubble diameter of the fine bubbles is 20 μm to 60 μm.

6. The extraction apparatus according to claim 1, wherein, when the diameter of the outlet channel is set to 100%, the average bubble diameter of the fine bubbles is 1.5% to 4%.

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