Concentration method

Abstract

To provide a technology capable of recovering concentrated liquid from a concentration apparatus more than ever.SOLUTION: A concentration method includes a concentration step, a recovery step, and an extraction step. In the concentration step, in a concentration apparatus comprising a concentration mechanism configured to concentrate a specific component contained in a liquid, and a circulation line configured to allow the liquid to flow out from and return to the concentration mechanism, the method concentrates, by the concentration mechanism, the specific component contained in the liquid while circulating the liquid through the circulation line. In the recovery step, after the concentration step, the method recovers at least some of the concentrated liquid from a recovery section. In the extraction step, further after the concentration step, the method extracts at least some of the concentrated liquid from an extraction section different from the recovery section.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] Disclosed embodiments relate to a concentration method. [Background technology]

[0002] Heavy water contains deuterium and tritium, which have larger mass numbers than hydrogen, and has a higher specific gravity than regular water. Heavy water has traditionally been used as a moderator and coolant in nuclear reactors, but it is also used for a variety of other purposes, such as as a heavy solvent (deuterated solvent) in analytical techniques such as NMR (Nuclear Magnetic Resonance).

[0003] Known techniques for concentrating heavy water contained in raw water to produce highly concentrated heavy water include the exchange reaction method, electrolysis method, distillation method, and double temperature exchange method. Of these production techniques, the electrolysis method utilizes the property that the electrolysis rate of heavy water is slower than that of normal water, to concentrate and separate heavy water from raw water containing heavy water, thereby producing highly concentrated heavy water (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-167702 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional technology, when highly concentrated heavy water produced by the concentration process is recovered from the concentration device, there is a risk that valuable highly concentrated heavy water will be wasted due to heavy water remaining in the device. Since the concentration process inevitably reduces the volume of heavy water, the more concentrated the heavy water, the larger the amount remaining in the device compared to the amount recovered. In other words, heavy water remaining in the device can be a major factor in reducing yield.

[0006] The present disclosure has been made in view of the above, and provides a technique that enables a larger amount of concentrated liquid to be recovered from a concentrating device. [Means for solving the problem]

[0007] A concentration method according to one aspect of the present disclosure includes a concentration step, a recovery step, and an extraction step. The concentration step is performed in a concentration apparatus including a concentration mechanism that concentrates a specific component contained in a liquid and a circulation line that exits the concentration mechanism and returns to the concentration mechanism, and the specific component contained in the liquid is concentrated by the concentration mechanism while circulating the liquid through the circulation line. The recovery step is performed after the concentration step, recovering at least a portion of the concentrated liquid from a recovery section. The extraction step is performed after the recovery step, withdrawing at least a portion of the concentrated liquid remaining in the circulation line from an extraction section different from the recovery section. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to recover a larger amount of concentrated liquid from the concentrating device. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a concentrating device according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing an example of the configuration of the concentration mechanism according to the embodiment. [Figure 3] FIG. 3 is a flowchart showing an example of a procedure of a concentration process performed by the concentration device according to the embodiment. [Figure 4] FIG. 4 is a flowchart showing an example of a procedure for a concentrated liquid recovery process according to the embodiment. [Figure 5] FIG. 5 is a diagram illustrating an example of an extracting unit according to an embodiment. [Figure 6] FIG. 6 is a diagram illustrating an example of an extracting unit according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the concentration method disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that the present disclosure is not limited to the embodiments shown below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of each element may differ from reality. Furthermore, the drawings may include parts with different dimensional relationships and ratios.

[0011] <Configuration of the concentrator> First, the configuration of a concentrating device 1 of the present disclosure will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a block diagram showing an example of the configuration of a concentrating device 1 according to an embodiment. As shown in Fig. 1, the concentrating device 1 according to the embodiment includes a concentrating mechanism 10 and a circulation line 20.

[0012] The concentration mechanism 10 concentrates a specific component contained in a liquid. The concentration mechanism 10 concentrates, for example, heavy water contained in a liquid containing water (H2O) and heavy water (D2O) (hereinafter also referred to as a raw material liquid). The raw material liquid is an example of a first liquid. A detailed configuration of the concentration mechanism 10 will be described later.

[0013] In the present disclosure, heavy water is not limited to DO containing only deuterium (D), but may also include DHO containing hydrogen (H), DTO and TO containing tritium (T), and the like.

[0014] The circulation line 20 is a flow path that exits the concentration mechanism 10 and returns to the concentration mechanism 10. Specifically, one end of the circulation line 20 is connected to a predetermined location in the anode chamber 13 in the concentration mechanism 10, and the other end of the circulation line 20 is connected to another location in the anode chamber 13.

[0015] In the concentrating apparatus 1, the raw material liquid in the concentrating mechanism 10 that is sent from the anode chamber 13 to the circulation line 20 is returned to the anode chamber 13 in the concentrating mechanism 10 through the circulation line 20.

[0016] In circulation line 20, a raw material liquid tank 31, a pump 32, a resin tower 33, and a filter 34 are provided in this order from the upstream side with respect to concentration mechanism 10. Raw material liquid is stored in raw material liquid tank 31, for example, when concentration treatment of the raw material liquid is started in concentrating device 1.

[0017] A spare tank 36 is connected to the raw material liquid tank 31 via a supply line 35 that is separate from the circulation line 20. The spare tank 36 stores, for example, a spare raw material liquid.

[0018] Then, by controlling the valve 37 provided on the supply line 35 to be in an open state, the spare raw material liquid stored in the spare tank 36 is supplied to the raw material liquid tank 31. This allows the raw material liquid of the desired volume to be concentrated even if the raw material liquid tank 31 does not have the desired volume.

[0019] In the present disclosure, the spare tank 36 does not necessarily have to be provided, and if the raw material liquid tank 31 has a sufficient capacity, the spare tank 36 may be omitted.

[0020] Pump 32 forms a circulation flow of the raw material liquid that leaves concentration mechanism 10, passes through circulation line 20, and returns to concentration mechanism 10. Resin tower 33 is filled with ion exchange resin. The ion exchange resin filled in resin tower 33 removes impurities such as impurity ions that become mixed into the raw material liquid during concentration treatment in concentration mechanism 10, circulation in circulation line 20, etc.

[0021] The filter 34 removes contaminants such as particles contained in the raw material liquid flowing through the circulation line 20 .

[0022] A recovery line 41, which is separate from the circulation line 20 and the supply line 35, is connected to the raw material liquid tank 31. This recovery line 41 is an example of a recovery section, and is connected to a concentrated liquid tank 42 and has a valve 43.

[0023] The concentrated liquid tank 42 is a tank that stores a liquid (hereinafter also referred to as concentrated liquid) in which heavy water is more concentrated than the raw material liquid after concentration processing in the concentration mechanism 10 and the circulation line 20 is completed.

[0024] In the example of Figure 1, an example is shown in which the recovery line 41 is connected to the raw material liquid tank 31, but the present disclosure is not limited to such an example, and the recovery line 41 may be connected to the circulation line 20 or a location other than the raw material liquid tank 31 provided in the circulation line 20.

[0025] A gas recovery line 51, which is a separate system from the circulation line 20, is connected to the concentration mechanism 10. The gas recovery line 51 connects the upper part of the cathode chamber 14 in the concentration mechanism 10 with a recovered gas reservoir 52.

[0026] The gas recovery line 51 sends the hydrogen gas and deuterium gas that are generated in the concentration mechanism 10 during the concentration process and that have accumulated in the cathode chamber 14 to the recovered gas storage unit 52. The recovered gas storage unit 52 stores the hydrogen gas and deuterium gas that are generated in the concentration mechanism 10 during the concentration process.

[0027] The hydrogen gas and deuterium gas stored in the recovered gas storage section 52 are sent to a recombination mechanism 54 via a gas line 53, where they are recombined with oxygen to become water and heavy water.

[0028] The mixture of water and heavy water (hereinafter also referred to as "dilute liquid") produced by the recombination mechanism 54 is a liquid having a lower concentration of heavy water than the raw material liquid, and is sent to the dilute liquid tank 56 via the recovery line 55 and stored in the dilute liquid tank 56. The dilute liquid is an example of the second liquid.

[0029] The concentrated liquid tank 42 and the diluted liquid tank 56 may each be provided with a return line (not shown) for returning the stored liquid to the raw material liquid tank 31.

[0030] 2 is a schematic diagram showing an example of the configuration of the concentration mechanism 10 according to the embodiment. The concentration mechanism 10 according to the embodiment is a device that produces an electrolytic gas and a concentrated liquid from a raw material liquid by, for example, electrolysis (electrolysis). For the concentration mechanism 10, for example, various known electrolytic cells can be used.

[0031] As shown in Fig. 2, the concentration mechanism 10 includes, for example, a processing chamber 11 and an electrolytic membrane 12. The processing chamber 11 is configured to be able to contain a liquid such as a raw material liquid. The electrolytic membrane 12 is positioned so as to divide the interior of the processing chamber 11 into two chambers. The electrolytic membrane 12 divides the processing chamber 11 into an anode chamber 13 and a cathode chamber 14.

[0032] The electrolysis membrane 12 has an electrolyte membrane 12a, an anode electrode 12b, and a cathode electrode 12c. Various known electrolyte membranes can be used for the electrolyte membrane 12a, such as a hydrogen ion conductive or hydroxide ion conductive electrolyte membrane, a hydrogen ion conductive or hydroxide ion conductive porous membrane, or a Nafion membrane.

[0033] The anode electrode 12b is positioned so as to cover the surface of the electrolyte membrane 12a on the anode chamber 13 side. The cathode electrode 12c is positioned so as to cover the surface of the electrolyte membrane 12a on the cathode chamber 14 side.

[0034] In this way, the electrolysis membrane 12 is configured such that the electrolyte membrane 12a is sandwiched between the anode electrode 12b and the cathode electrode 12c. Various known materials can be used for the anode electrode 12b and the cathode electrode 12c. For example, an iridium-based catalyst can be used for the anode electrode 12b, and a platinum-based catalyst can be used for the cathode electrode 12c.

[0035] <Details of concentration process> Next, the concentration process performed by the concentrating device 1 according to the embodiment will be described in detail with reference to Fig. 3 to Fig. 6. Fig. 3 is a flowchart showing an example of the procedure of the concentration process performed by the concentrating device 1 according to the embodiment.

[0036] In the concentration process according to the embodiment, first, an operator or the like performs a preparation process to prepare a raw material liquid to be subjected to the concentration process (step S101). For example, the operator or the like prepares a liquid containing water and heavy water to be stored in the concentrated liquid tank 42 (see FIG. 1) or the diluted liquid tank 56 (see FIG. 1), or a liquid containing water and heavy water to be stored in another tank, as the raw material liquid, and stores this raw material liquid in the raw material liquid tank 31 (see FIG. 1).

[0037] In the process of step S101, the operator may store the prepared raw material liquid in the preliminary tank 36 (see FIG. 1) in addition to the raw material liquid tank 31.

[0038] Next, the control unit that controls each part of the concentrating device 1 (see Figure 1) operates the pump 32 (see Figure 1) to circulate the raw material liquid through the circulation line 20 (see Figure 1), and also operates the concentration mechanism 10 (see Figure 1) to perform a concentration process to concentrate the raw material liquid (step S102).

[0039] Specifically, in this concentration process, in the concentration mechanism 10, a predetermined positive voltage is applied to the anode electrode 12b (see FIG. 2) of the electrolytic membrane 12 (see FIG. 2), and a predetermined negative voltage is applied to the cathode electrode 12c (see FIG. 2).

[0040] Then, in the anode chamber 13 (see FIG. 2), the chemical reactions of the following formulas (1) and (2) occur. H2O → 2H + + 1 / 2O2···(1) D2O → 2D + + 1 / 2O2···(2)

[0041] The hydrogen ions and deuterium ions generated by the above formulas (1) and (2) permeate the electrolytic membrane 12 and move to the cathode chamber 14 (see FIG. 2). Then, in the cathode chamber 14, the chemical reactions of the following formulas (3) and (4) occur. 2H + + 2e - → H2···(3) 2D + + 2e - → D2···(4)

[0042] Here, since the overvoltage of water is smaller than the overvoltage of heavy water, the chemical reaction of formula (1) occurs more likely than the chemical reaction of formula (2) in the concentrating mechanism 10. That is, since water is electrolyzed preferentially over heavy water in the concentrating mechanism 10, water is preferentially removed as gas from the raw material liquid. This allows the concentrating mechanism 10 to concentrate the heavy water contained in the raw material liquid.

[0043] In the concentration process according to the embodiment, the heavy water contained in the raw material liquid is concentrated by operating the concentration mechanism 10 while circulating the raw material liquid through the circulation line 20. This allows a larger amount of raw material liquid than can be accommodated in the concentration mechanism 10 itself to be uniformly concentrated, thereby enabling the concentration process to be carried out efficiently.

[0044] Returning to the explanation of Fig. 3, in parallel with the concentration process (step S102) explained up to this point, the control unit of the concentration device 1 performs a gas recovery process (step S103) and a recombination process (step S104).

[0045] In the gas recovery process (step S103), the gas generated in the concentration mechanism 10 is recovered. Specifically, the control unit recovers the hydrogen gas and deuterium gas generated by the chemical reactions of the above formulas (3) and (4) from the cathode chamber 14. Then, the control unit sends the recovered hydrogen gas and deuterium gas to the recovered gas storage unit 52 (see FIG. 1) via the gas recovery line 51 (see FIG. 1).

[0046] In the recombination process (step S104), the hydrogen gas and deuterium gas recovered in the gas recovery process (step S103) are recombined with oxygen in the recombination mechanism 54 (see FIG. 1) to produce an aqueous solution containing water and heavy water.

[0047] For example, in an embodiment, the recovered hydrogen gas and deuterium gas are combusted in air using any of various known hydrogen burners to produce an aqueous solution containing water and heavy water, which allows the hydrogen gas and deuterium gas to be efficiently recombined with oxygen.

[0048] The recombination mechanism 54 according to the embodiment is not limited to a system in which hydrogen gas and deuterium gas are recombined with oxygen using a hydrogen burner. For example, the recombination mechanism 54 may recombine hydrogen gas and deuterium gas with oxygen using a catalyst or a fuel cell, or may recombine hydrogen gas and deuterium gas with oxygen using a method other than these.

[0049] In the embodiment, as described above, water is electrolyzed preferentially over heavy water in the concentrating mechanism 10, and therefore hydrogen gas is generated preferentially over deuterium gas. As a result, in the aqueous solution containing water and heavy water generated in the recombination mechanism 54, water is concentrated compared to the raw material liquid.

[0050] Therefore, in the concentrating apparatus 1 according to the embodiment, the aqueous solution containing water and heavy water produced in the recombination mechanism 54 becomes a diluted solution having a lower concentration of heavy water than the raw material liquid. The control unit stores the diluted solution produced in the recombination mechanism 54 in the diluted solution tank 56.

[0051] Returning to the explanation of Fig. 3, following the processes of steps S102 to S104 described above, the control unit of the concentrating device 1 determines whether the concentration process (step S102) has ended (step S105). For example, when the process of step S102 has been performed continuously for a predetermined time, the control unit can consider that the raw material liquid has been concentrated to a desired concentration and determine that the concentration process has ended.

[0052] In the present disclosure, the process of step S105 is not limited to determining that the concentration process has ended when the process of step S102 has been performed continuously for a predetermined time. For example, in the present disclosure, a concentration meter may be separately installed in the circulation line 20, and the concentration process may be determined to have ended when the measurement value of this concentration meter reaches a desired concentration.

[0053] If it is determined that the concentration process has been completed (Yes in step S105), a concentrated liquid recovery process is performed to recover the concentrated raw liquid, i.e., the concentrated liquid (step S106), and the series of concentration processes is terminated. The details of this concentrated liquid recovery process will be described later.

[0054] On the other hand, if it is determined that the concentration process has not been completed (No at step S105), the process returns to steps S102 to S104.

[0055] 4 is a flowchart showing an example of the procedure of the concentrated liquid recovery process according to the embodiment. In the concentrated liquid recovery process according to the embodiment, first, the control unit of the concentrating device 1 (see FIG. 1) performs a recovery process to recover at least a portion of the concentrated liquid stored in the concentrating mechanism 10 (see FIG. 1), the circulation line 20 (see FIG. 1), etc. from the recovery line 41 (see FIG. 1) (step S201).

[0056] Specifically, the control unit stops the operation of the concentration mechanism 10 and the pump 32 (see FIG. 1). Then, the control unit changes the valve 43 (see FIG. 1) from a closed state to an open state, thereby recovering at least a portion of the concentrated liquid stored in the concentration mechanism 10, the circulation line 20, etc., from the recovery line 41. The concentrated liquid recovered by this recovery process is stored in the concentrated liquid tank 42 (see FIG. 1).

[0057] Next, after this recovery process (step S201), the worker or the like performs an extraction process to extract at least a portion of the concentrated liquid remaining in the circulation line 20 from an extraction section 60 (see Figure 5) different from the recovery line 41 (step S202), thereby completing the series of concentrated liquid recovery processes.

[0058] This extraction process allows the concentrated liquid remaining in areas that are difficult to recover to be extracted to the outside from the recovery line 41. Therefore, according to the embodiment, a larger amount of concentrated liquid can be recovered from the concentrating device 1.

[0059] 5 and 6 are diagrams showing an example of the extraction section 60 according to the embodiment. Fig. 5 shows a portion of the circulation line 20 that is U-shaped and convex downward.

[0060] 5, the outlet 60 is provided in the portion 20a of the circulation line 20 that is at the minimum height. The outlet 60 is, for example, a pipe through which a liquid can flow, and has one end connected to the portion 20a of the circulation line 20 and the other end open.

[0061] Then, in the extraction process of step S202, the worker places a collection container at the other end of the extraction section 60 and opens the valve 61 provided in the extraction section 60 from the closed state, thereby recovering the extracted concentrated liquid in the collection container. This allows a larger amount of concentrated liquid to be recovered from the concentrating device 1.

[0062] When the concentrated liquid is extracted from the concentrating device 1, the extraction may be carried out substantially by the gravity of the concentrated liquid alone, without using a liquid transport mechanism such as the pump 32. When considering the extraction of concentrated liquid that has accumulated in a certain location, if 95% or more of the volume can be extracted by gravity alone without using any liquid transport mechanism, the extraction at that location may be considered to have been carried out substantially by gravity alone.

[0063] The recovery process is preferably carried out using a liquid delivery mechanism such as the pump 32, and the extraction process is preferably carried out substantially by the weight of the concentrated liquid without using a liquid delivery mechanism, thereby reducing the energy consumption for driving the liquid delivery mechanism involved in the extraction process.

[0064] 5, the extraction section 60 may be provided in a portion 20a that is at a minimum height in the circulation line 20. This allows a larger amount of concentrated liquid to be extracted from the portion 20a where the concentrated liquid remaining in the circulation line 20 collects due to its own weight.

[0065] Therefore, according to the embodiment, it is possible to recover a larger amount of concentrated liquid from the concentrating device 1.

[0066] The minimum height position is determined by the relative height in the circulation line 20, and can be determined, for example, at the lowest position in the line where a liquid pool occurs that cannot be recovered by a pump or the like. As will be described later, heavy water tends to concentrate at the lower part. In order to make it easier to selectively extract heavy water that is located at the lower part of the liquid pool, it is preferable that the extraction section 60 be provided at the minimum height position in the liquid pool.

[0067] 6 shows a resin tower 33 provided in the circulation line 20 (see FIG. 1). Note that FIG. 6 omits the illustration of the circulation line 20 (see FIG. 1) connected to the resin tower 33. In addition, in the present disclosure, the number of resin towers 33 provided in the circulation line 20 is not limited to one, and multiple resin towers 33 may be provided in the circulation line 20.

[0068] As described above, the inside of this resin tower 33 is filled with ion exchange resin. The ion exchange resin filled in the resin tower 33 removes impurities such as impurity ions that are mixed into the raw material liquid during the concentration treatment in the concentration mechanism 10, circulation in the circulation line 20, and the like.

[0069] 6, an extracting section 60 is provided at the bottom 33a of the resin tower 33. In the example of Fig. 6, one end of the extracting section 60 is connected to the bottom 33a of the resin tower 33, and the other end is open.

[0070] Then, in the extraction process of step S202, the worker places a collection container at the other end of the extraction section 60 and opens the valve 61 provided in the extraction section 60 from the closed state, thereby recovering the extracted concentrated liquid in the collection container. This allows a larger amount of concentrated liquid to be recovered from the concentrating device 1.

[0071] 6, the concentrated liquid may be extracted together with the ion exchange resin from the extraction section 60. This allows the concentrated liquid remaining between the ion exchange resins to be extracted to the outside, making it possible to recover even more concentrated liquid from the concentrating device 1.

[0072] In the example of Figure 6, the concentrated liquid is not limited to being extracted together with the ion exchange resin from the extraction section 60. By providing a mesh member or the like on one end side of the extraction section 60, it is also possible to extract only the concentrated liquid from the resin tower 33 without extracting the ion exchange resin from inside the resin tower 33.

[0073] This allows the ion exchange resin inside the resin tower 33 to be easily reused in the next concentration treatment in the concentration device 1.

[0074] In addition, in the examples of Figures 5 and 6, the extraction section 60 is shown to be provided at the minimum height portion 20a of the circulation line 20 or at the bottom 33a of the resin tower 33, but the present disclosure is not limited to such examples.

[0075] For example, the extraction unit 60 may be provided at the bottom of the processing chamber 11 (see FIG. 2) in the concentration mechanism 10 (see FIG. 2), or at the bottom of the filter 34 (see FIG. 1). This also makes it possible to recover a larger amount of concentrated liquid from the concentration device 1.

[0076] In addition, in the embodiment, in the extraction process of step S202, the extraction of the concentrated liquid may be promoted by injecting gas into the circulation line 20. This allows the injected gas to push the concentrated liquid remaining in the circulation line 20 out to the extraction section 60, making it possible to recover even more concentrated liquid from the concentrating device 1.

[0077] The medium for promoting the extraction of the concentrated liquid is not limited to gas, and the extraction of the concentrated liquid may be promoted using a medium that is immiscible with the concentrated liquid, such as oil. This also makes it possible to recover even more concentrated liquid from the concentrating device 1.

[0078] In addition, in the embodiment, the circulation line 20 leading to the extraction unit 60 may be arranged so as to incline downward toward the extraction unit 60. This allows the concentrated liquid to be smoothly sent to the extraction unit 60, and therefore, a larger amount of concentrated liquid can be recovered from the concentrating device 1.

[0079] Furthermore, in an embodiment, among the concentrated liquid remaining in the circulation line 20, heavy water, which has a higher specific gravity than water, may be preferentially extracted from the extraction section 60. Because heavy water has a higher specific gravity than water, the concentration tends to be higher in the lower portions. This allows for selectively obtaining a concentrated liquid with a higher concentration by preferentially or stepwise extracting the heavy water from the lower portions.

[0080] In the above embodiment, an example in which the extraction process is performed after the recovery process is shown, but the present disclosure is not limited to such an example, and the recovery process may be performed after the extraction process, or the recovery process and the extraction process may be performed simultaneously, which also allows a larger amount of concentrated liquid to be recovered.

[0081] On the other hand, by performing the extraction process after the recovery process, the amount of concentrated liquid extracted in the extraction process can be minimized, thereby minimizing the effort required by workers, etc.

[0082] In addition, in the above embodiment, a larger amount of concentrated liquid obtained by concentrating heavy water is recovered from the concentrating device 1, but the present disclosure is not limited to this example, and the technology of the present disclosure may be applied to a process for recovering a concentrated liquid obtained by concentrating a component other than heavy water. This also makes it possible to recover a larger amount of concentrated liquid.

[0083] The concentration method according to the embodiment includes a concentration step (step S102), a recovery step (step S201), and an extraction step (step S202). In the concentration step (step S102), a concentrating device 1 includes a concentration mechanism 10 that concentrates a specific component (heavy water) contained in a liquid (raw material liquid) and a circulation line 20 that flows from the concentration mechanism 10 and returns to the concentration mechanism 10. The concentration step (step S201) involves recovering at least a portion of the concentrated liquid (concentrated liquid) from the recovery section (recovery line 41) after the concentration step (step S102). The extraction step (step S202) involves recovering at least a portion of the concentrated liquid (concentrated liquid) from an extraction section 60, which is different from the recovery section (recovery line 41), after the concentration step (step S102). This allows a larger amount of concentrated liquid to be recovered from the concentrating device 1.

[0084] In the concentration method according to the embodiment, the extraction step (step S202) extracts at least a portion of the concentrated liquid (concentrated liquid) remaining in the circulation line 20 after the recovery step (step S201). This minimizes the effort required by workers and the like.

[0085] In the concentration method according to the embodiment, the concentration step (step S102) concentrates the heavy water contained in the liquid (raw material liquid), thereby making it possible to recover a larger amount of valuable highly concentrated heavy water.

[0086] Furthermore, in the concentration method according to the embodiment, the extraction section 60 is provided at a position (section 20a) where the height is minimal in the circulation line 20. This allows a larger amount of concentrated liquid to be recovered from the concentrating apparatus 1.

[0087] In the concentration method according to the embodiment, the concentrating device 1 further includes a resin tower 33 that is provided in the circulation line 20 and is filled with an ion exchange resin. In the extraction step (step S202), the concentrated liquid (concentrated liquid) is extracted together with the ion exchange resin from an extraction section 60 provided at the bottom 33a of the resin tower 33. This allows a larger amount of concentrated liquid to be recovered from the concentrating device 1.

[0088] In the concentration method according to the embodiment, the extraction step (step S202) is performed by the weight of the concentrated liquid (concentrated liquid), thereby reducing energy consumption for driving the liquid delivery mechanism.

[0089] In the concentration method according to the embodiment, the extraction step (step S202) promotes extraction of the concentrated liquid (concentrated liquid) by injecting gas into the circulation line 20. This allows a larger amount of concentrated liquid to be recovered from the concentrating device 1.

[0090] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0091] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0092] 1 Concentrator 10 Concentration mechanism 20 Circulation Line 20a part 31 Raw material liquid tank 32 Pump 33 Resin Tower 33a bottom 34 Filters 41 Recovery line (example of recovery section) 42 Concentrate tank 52 Recovered gas storage section 54 Recombination mechanism 56 Dilute Liquid Tank 60 Extraction section 61 Valve

Claims

1. In a concentrating apparatus including a concentration mechanism that concentrates a specific component contained in a liquid and a circulation line that exits from the concentration mechanism and returns to the concentration mechanism, a concentration step of concentrating the specific component contained in the liquid by the concentration mechanism while circulating the liquid through the circulation line; a recovery step of recovering at least a portion of the concentrated liquid from a recovery section after the concentration step; a withdrawal step of withdrawing at least a portion of the concentrated liquid from a withdrawal section different from the recovery section after the concentration step; A concentration method comprising:

2. The extracting step extracts at least a portion of the concentrated liquid remaining in the circulation line after the recovering step. The concentration method according to claim 1.

3. The concentration step is a step of concentrating heavy water contained in the liquid. The concentration method according to claim 1 or 2.

4. The extraction section is provided at a position where the height is minimum in the circulation line. The concentration method according to claim 1 or 2.

5. The concentrator further includes a resin tower provided in the circulation line and filled with an ion exchange resin, The extracting step involves extracting the concentrated liquid together with the ion exchange resin from the extracting section provided at the bottom of the resin tower. The concentration method according to claim 1 or 2.

6. The extraction step is carried out by the weight of the concentrated liquid. The concentration method according to claim 1 or 2.

7. The extraction step involves injecting a gas into the circulation line to promote extraction of the concentrated liquid. The concentration method according to claim 1 or 2.

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