Concentration method

Abstract

To provide a technology capable of efficiently performing concentration processing.SOLUTION: A concentration method includes a first concentration step, a first mixing step, and a second concentration step. In the first concentration step, a specific component contained in a liquid having a first concentration range with respect to the specific component is concentrated to produce a first concentrated liquid having a second concentration range that is higher than the first concentration range. In the first mixing step, the first concentrated liquid obtained in the first concentration step is mixed with another liquid having the second concentration range. In the second concentration step, the specific component contained in the mixed liquid obtained in the first mixing step is concentrated to produce a second concentrated liquid having a third concentration range that is higher than the second concentration range.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] As described above, in the concentration process in which a raw material solution having a lower concentration than the desired concentration is concentrated to obtain a concentrated solution having the desired concentration, there is room for further improvement in terms of efficiency of the concentration process, which is particularly difficult when each component cannot be selectively extracted from the raw material solution.

[0006] The present disclosure has been made in view of the above, and provides a technique that can efficiently perform a concentration process for concentrating a specific component contained in a liquid. [Means for solving the problem]

[0007] A concentration method according to one embodiment of the present disclosure includes a first concentration step, a first mixing step, and a second concentration step. The first concentration step concentrates a specific component contained in a liquid having a first concentration range with respect to the specific component to produce a first concentrated liquid having a second concentration range higher than the first concentration range. The first mixing step mixes the first concentrated liquid obtained in the first concentration step with another liquid having the second concentration range. The second concentration step concentrates the specific component contained in the mixed liquid obtained in the first mixing step to produce a second concentrated liquid having a third concentration range higher than the second concentration range. [Effects of the Invention]

[0008] According to the present disclosure, concentration treatment can be carried out efficiently. [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 diagram illustrating a series of steps in the concentration process according to the embodiment. [Figure 5] FIG. 5 is a diagram for explaining the decrease in efficiency that occurs naturally when liquids with different concentration ranges are mixed. [Figure 6] FIG. 6 is a diagram showing the relationship between the heavy water concentration of the raw material liquid (concentration 85.0%) and the electrolysis rate required for the concentration treatment. [Figure 7] FIG. 7 is a diagram for explaining a specific example of the concentration process according to the embodiment. [Figure 8]FIG. 8 is a diagram for explaining a specific example of the concentration process according to the embodiment. [Figure 9] FIG. 9 is a diagram for explaining a specific example of the concentration process according to the embodiment. [Figure 10] FIG. 10 is a block diagram showing an example of the configuration of a concentration system according to another 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, there may be parts in which the dimensional relationships and ratios differ between the drawings. Furthermore, unless otherwise specified, "%" represents % by weight.

[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. For example, the concentration mechanism 10 concentrates heavy water contained in a liquid (hereinafter also referred to as a raw material liquid) containing water (H2O) and heavy water (D2O). 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. The recovery line 41 branches into a plurality of branch lines 42a to 42f.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] A recovery line 55, which is separate from the gas line 53, is connected to the recombination mechanism 54. This recovery line 55 branches into a plurality of branch lines 56b to 56g.

[0028] The tank group 60 includes a first tank 61 to a seventh tank 67. The first tank 61 to the seventh tank 67 store a liquid in which heavy water is more concentrated than the raw material liquid after the concentration process in the concentration mechanism 10 and the circulation line 20 is completed (hereinafter also referred to as a concentrated liquid or "concentrated liquid"), and a mixed liquid of water and heavy water produced in the recombination mechanism 54 (hereinafter also referred to as a "dilute liquid" or "dilute liquid").

[0029] The first tank 61 is connected to the raw material liquid tank 31 via a branch line 42a and a recovery line 41. A valve 43a is provided on the branch line 42a.

[0030] The second tank 62 is connected to the raw material liquid tank 31 via a branch line 42b and a recovery line 41. The second tank 62 is also connected to the recombination mechanism 54 via a branch line 56b and a recovery line 55. A valve 43b is provided in the branch line 42b, and a valve 57b is provided in the branch line 56b.

[0031] The third tank 63 is connected to the raw material liquid tank 31 via a branch line 42c and a recovery line 41. The third tank 63 is also connected to the recombination mechanism 54 via a branch line 56c and a recovery line 55. A valve 43c is provided in the branch line 42c, and a valve 57c is provided in the branch line 56c.

[0032] The fourth tank 64 is connected to the raw material liquid tank 31 via a branch line 42d and a recovery line 41. The fourth tank 64 is also connected to the recombination mechanism 54 via a branch line 56d and a recovery line 55. A valve 43d is provided in the branch line 42d, and a valve 57d is provided in the branch line 56d.

[0033] The fifth tank 65 is connected to the raw material liquid tank 31 via a branch line 42e and a recovery line 41. The fifth tank 65 is also connected to the recombination mechanism 54 via a branch line 56e and a recovery line 55. A valve 43e is provided in the branch line 42e, and a valve 57e is provided in the branch line 56e.

[0034] The sixth tank 66 is connected to the raw material liquid tank 31 via a branch line 42f and a recovery line 41. The sixth tank 66 is also connected to the recombination mechanism 54 via a branch line 56f and a recovery line 55. A valve 43f is provided on the branch line 42f, and a valve 57f is provided on the branch line 56f.

[0035] The seventh tank 67 is connected to the recombination mechanism 54 via a branch line 56g and a recovery line 55. A valve 57g is provided in the branch line 56g.

[0036] In the concentrating device 1 according to the embodiment, the valves 43a to 43f are selectively opened and closed, so that the concentrated liquid stored in the raw liquid tank 31 and the circulation line 20, etc., is selectively sent to the first tank 61 to the sixth tank 66 and selectively stored in the first tank 61 to the sixth tank 66.

[0037] In addition, in the concentration device 1 of the embodiment, by selectively opening and closing valves 57b to 57g, the diluted liquid generated in the recombination mechanism 54 is selectively sent to the second tank 62 to the seventh tank 67 and selectively stored in the second tank 62 to the seventh tank 67.

[0038] The first tank 61 to the seventh tank 67 may each be provided with a return line (not shown) for returning the stored liquid to the raw material liquid tank 31.

[0039] 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. The concentration mechanism 10 can be, for example, any of various known electrolytic cells.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] <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. 9. 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.

[0045] 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, as raw material liquid, a liquid containing water and heavy water to be stored in the second tank 62 to the sixth tank 66 (see FIG. 1) or a liquid containing water and heavy water to be stored in another tank, and stores this raw material liquid in the raw material liquid tank 31 (see FIG. 1).

[0046] 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.

[0047] 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).

[0048] 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).

[0049] 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)

[0050] 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)

[0051] 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.

[0052] 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.

[0053] 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).

[0054] 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).

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] The control unit selects one tank from the second tank 62 to the seventh tank 67 (see FIG. 1) and stores the diluted liquid produced by the recombination mechanism 54 in that tank. The tank selection process will be described in detail later.

[0061] 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.

[0062] 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.

[0063] Then, if it is determined that the concentration process has been completed (step S105, Yes), the control unit performs a concentrated liquid recovery process to recover the raw liquid after the concentration process has been completed, i.e., the concentrated liquid (step S106), thereby completing the series of concentration processes.

[0064] 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.

[0065] In the concentrated liquid recovery process of step S106, the control unit selects one tank from the first tank 61 to the sixth tank 66 (see FIG. 1) and stores the concentrated liquid recovered from the raw material liquid tank 31, the circulation line 20, etc. The details of this tank selection process will be described with reference to FIG.

[0066] 4 is a diagram illustrating a series of steps in the concentration process according to the embodiment. In the concentration process according to the embodiment, the concentration ranges of the concentrated liquid and diluted liquid stored in each tank of the concentrating device 1 are set in advance.

[0067] For example, in the example of Fig. 4, a concentration range A is set where the concentration of heavy water is 98% or more, and a concentrated solution of this concentration range A is stored in the first tank 61 (see Fig. 1). Also, in the example of Fig. 4, a concentration range B where the concentration of heavy water is 96% to 98% is set, and a concentrated solution and a diluted solution of this concentration range B are stored in the second tank 62 (see Fig. 1).

[0068] 4, a concentration range C of 90% to 96% for the heavy water concentration is set, and concentrated and diluted solutions in this concentration range C are stored in the third tank 63 (see FIG. 1). Also, in the example of FIG. 4, a concentration range D of 82% to 90% for the heavy water concentration is set, and concentrated and diluted solutions in this concentration range D are stored in the fourth tank 64 (see FIG. 1).

[0069] 4, a concentration range E of 70% to 82% for the heavy water concentration is set, and concentrated and diluted solutions in this concentration range E are stored in the fifth tank 65 (see FIG. 1). Also, in the example of FIG. 4, a concentration range F of 55% to 70% for the heavy water concentration is set, and concentrated and diluted solutions in this concentration range F are stored in the sixth tank 66 (see FIG. 1).

[0070] In the example of FIG. 4, a concentration range G is set in which the concentration of heavy water is 55% or less, and a diluted solution of this concentration range G is stored in the seventh tank 67 (see FIG. 1).

[0071] Note that the number of concentration ranges and threshold values ​​shown in Figure 4 are merely examples, and the number of concentration ranges and threshold values ​​can be set appropriately depending on the concentration of available raw material liquids and the desired concentration to be ultimately produced.

[0072] 4, first, a concentration process is performed in the concentrator 1 using a raw material liquid 1 having a concentration range D as the raw material liquid. As a result, a concentrated liquid 1 having a concentration range C and a diluted liquid 1 having a concentration range E are recovered. That is, the raw material liquid 1 having a concentration range D is divided into a concentrated liquid 1 having a concentration range C and a diluted liquid 1 having a concentration range E. The concentrated liquid 1 is stored in the third tank 63 corresponding to the concentration range C, and the diluted liquid 1 is stored in the fifth tank 65 corresponding to the concentration range E.

[0073] 4, a concentrated solution 1 having a concentration range C is mixed with a raw material solution 2 having the same concentration range C to produce a mixed solution 1 having a concentration range C. The raw material solution 2 is produced separately, for example, by a separate concentration process or separate concentrating device (not shown). The mixed solution 1 having a concentration range C is then used as the raw material solution and subjected to a concentration process in the concentrating device 1.

[0074] As a result, a concentrated solution 2 of concentration range B and a diluted solution 2 of concentration range D are collected. That is, the mixed solution 1 of concentration range C is distributed into a concentrated solution 2 of concentration range B and a diluted solution 2 of concentration range D. The concentrated solution 2 is stored in the second tank 62 corresponding to the concentration range B, and the diluted solution 2 is stored in the fourth tank 64 corresponding to the concentration range D.

[0075] Next, in the example of Fig. 4, a diluted solution 1 having a concentration range E is mixed with a raw material solution 3 having the same concentration range E to produce a mixed solution 2 having a concentration range E. The raw material solution 3 is produced separately, for example, by a separate concentration process or separate concentrating device (not shown). Then, the mixed solution 2 having the concentration range E is used as the raw material solution and subjected to a concentration process in the concentrating device 1.

[0076] As a result, a concentrated solution 3 of concentration range D and a diluted solution 3 of concentration range F are collected. That is, the mixed solution 2 of concentration range E is distributed into a concentrated solution 3 of concentration range D and a diluted solution 3 of concentration range F. The concentrated solution 3 is stored in the fourth tank 64 corresponding to the concentration range D, and the diluted solution 3 is stored in the sixth tank 66 corresponding to the concentration range F.

[0077] 4, a concentrated solution 2 having a concentration range B is mixed with a raw material solution 4 having the same concentration range B to produce a mixed solution 3 having a concentration range B. The raw material solution 4 is produced separately, for example, by a separate concentration process or separate concentrating device (not shown). The mixed solution 3 having a concentration range B is then used as the raw material solution and subjected to a concentration process in the concentrating device 1.

[0078] As a result, a concentrated solution 4 of concentration range A and a diluted solution 4 of concentration range C are collected. That is, the mixed solution 3 of concentration range B is distributed into a concentrated solution 4 of concentration range A and a diluted solution 4 of concentration range C. The concentrated solution 4 is stored in the first tank 61 corresponding to the concentration range A, and the diluted solution 4 is stored in the third tank 63 corresponding to the concentration range C.

[0079] 4, a diluted solution 2 having a concentration range D is mixed with a concentrated solution 3 having the same concentration range D to produce a mixed solution 4 having a concentration range D. Then, the mixed solution 4 having a concentration range D is used as a raw material liquid and is subjected to a concentration process in a concentrating device 1.

[0080] As a result, a concentrated solution 5 of concentration range C and a diluted solution 5 of concentration range E are collected. That is, the mixed solution 4 of concentration range D is distributed into a concentrated solution 5 of concentration range C and a diluted solution 5 of concentration range E. The concentrated solution 5 is stored in the third tank 63 corresponding to the concentration range C, and the diluted solution 5 is stored in the fifth tank 65 corresponding to the concentration range E.

[0081] Next, in the example of Fig. 4, a diluted solution 3 having a concentration range F is mixed with a raw material solution 5 having the same concentration range F to produce a mixed solution 5 having a concentration range F. The raw material solution 5 is produced separately, for example, by a separate concentration process or separate concentration device (not shown). Then, the mixed solution 5 having the concentration range F is used as the raw material solution and subjected to a concentration process in the concentration device 1.

[0082] As a result, a concentrated solution 6 of concentration range E and a diluted solution 6 of concentration range G are collected. That is, the mixed solution 5 of concentration range F is distributed into a concentrated solution 6 of concentration range E and a diluted solution 6 of concentration range G. The concentrated solution 6 is stored in the fifth tank 65 corresponding to the concentration range E, and the diluted solution 6 is stored in the seventh tank 67 corresponding to the concentration range G.

[0083] 4, a dilute solution 4 having a concentration range C is mixed with a concentrated solution 5 having the same concentration range C to produce a mixed solution 6 having a concentration range C. Then, the mixed solution 6 having a concentration range C is used as a raw material liquid and subjected to a concentration process in the concentrating device 1.

[0084] As a result, a concentrated solution 7 of concentration range B and a diluted solution 7 of concentration range D are collected. That is, the mixed solution 6 of concentration range C is divided into a concentrated solution 7 of concentration range B and a diluted solution 7 of concentration range D. The concentrated solution 7 is stored in the second tank 62 corresponding to the concentration range B, and the diluted solution 7 is stored in the fourth tank 64 corresponding to the concentration range D.

[0085] 4, a diluted solution 5 having a concentration range E is mixed with a concentrated solution 6 having the same concentration range E to produce a mixed solution 7 having a concentration range E. Then, the mixed solution 7 having the concentration range E is used as a raw material liquid and is subjected to a concentration process in the concentrating device 1.

[0086] As a result, a concentrated solution 8 of concentration range D and a diluted solution 8 of concentration range F are collected. That is, the mixed solution 7 of concentration range E is divided into a concentrated solution 8 of concentration range D and a diluted solution 8 of concentration range F. The concentrated solution 8 is stored in the fourth tank 64 corresponding to the concentration range D, and the diluted solution 8 is stored in the sixth tank 66 corresponding to the concentration range F.

[0087] As described above, in the concentration process according to the embodiment, a concentrated liquid 4 having a high concentration in the concentration range A can be efficiently produced from a raw material liquid 1 having a concentration range D through multiple stages of concentration processes.

[0088] Furthermore, in the concentration process according to the embodiment, in order to perform an efficient concentration process, the raw material liquid 1 or the mixed liquids 1 to 7 may be prepared in the raw material liquid tank 31 or the like so as to approximate the specified volume of the raw material liquid specified for each individual concentrating device 1. This allows the concentration process to be performed with a volume of the raw material liquid that allows for efficient concentration process, thereby making the concentration process efficient.

[0089] Furthermore, in the concentration process according to the embodiment, as described above, when preparing a specified volume or a volume close to the specified volume of raw material liquid in the raw material liquid preparation process (step S101 in FIG. 3), it is advisable to mix raw material liquid, concentrated liquid, and diluted liquid of the same concentration range.

[0090] This allows the concentration process to be carried out more efficiently than when preparing a raw material solution by mixing raw material solutions, concentrated solutions, and diluted solutions with different concentration ranges. The reason for this will be explained with reference to FIG. 5.

[0091] Figure 5 is a diagram for explaining the decrease in efficiency that occurs naturally when liquids with different concentration ranges are mixed. In the example of Figure 5, 550 L of concentrated liquid with a concentration of 95.8% and 700 L of diluted liquid with a concentration of 85.0% are mixed to produce 1250 L of mixed liquid with a concentration of 89.8%.

[0092] In this mixing process, the process of producing a mixed solution with a concentration of 89.8% from a concentrated solution with a concentration of 95.8% involves a decrease in concentration, which is a negative factor in efficient concentration processing.

[0093] On the other hand, in this mixing process, the process of generating a mixed solution with a concentration of 89.8% from a dilute solution with a concentration of 85.0% involves an increase in concentration, which is a positive factor in efficient concentration processing.

[0094] Therefore, we will consider the magnitude of these negative and positive factors. As shown in Figure 5, the negative factors mentioned above result in the generation of 940L - 550L = 390L of concentration, which was originally unnecessary but became necessary due to the mixing process.

[0095] On the other hand, in the positive factor mentioned above, the amount of concentrate that was originally needed but became unnecessary due to the mixing process is 920 L - 700 L = 220 L. In other words, in the example of Figure 5, it can be calculated that an extra 390 L - 220 L = 170 L of concentrate was required due to mixing of concentrated and diluted liquids with different concentration ranges.

[0096] Thus, the inventors of the present application have found that mixing liquids having different concentration ranges in itself reduces the efficiency of the concentration process.

[0097] Therefore, in the concentration process according to the embodiment, in the preparation process of the raw material liquid, when preparing a raw material liquid of a set volume or a volume close to the set volume of the concentrating device 1, the raw material liquid, concentrated liquid, and diluted liquid of the same concentration range are mixed. This makes it possible to suppress a decrease in the efficiency of the concentration process that occurs during the mixing process, thereby enabling the concentration process to be carried out efficiently.

[0098] Figure 6 shows the relationship between the heavy water concentration of the feed solution (concentration 85.0%) and the electrolysis rate required for the concentration treatment. Here, the vertical axis represents the electrolysis rate required to increase the concentration by 0.05% at the corresponding heavy water concentration on the horizontal axis, and the separation factor between DO and HO by electrolysis is set to 3.0. As shown in Figure 6, when the heavy water concentration of the feed solution is 94% or higher, the electrolysis rate required for the concentration treatment tends to increase.

[0099] That is, mixing a liquid having a heavy water concentration of 94% or more with a liquid having a heavy water concentration significantly lower than that of this liquid will significantly reduce the efficiency of the concentration process.

[0100] Therefore, in the concentration process according to the embodiment, when a new raw material liquid is produced by mixing a liquid having a concentration of 94% or more with another liquid, it is preferable that these liquids have the same concentration range, which allows the concentration process to be carried out more efficiently.

[0101] 4, the width of a high density range may be narrower than the width of a low density range. For example, the width of density range F may be narrower than the width of density range G. Furthermore, the width of density range E may be narrower than the width of density range F.

[0102] Furthermore, the width of concentration range D may be narrower than the width of concentration range E. Furthermore, the width of concentration range C may be narrower than the width of concentration range D. Furthermore, the width of concentration range B may be narrower than the width of concentration range C. Furthermore, the width of concentration range A may be narrower than the width of concentration range B.

[0103] As mentioned above, when two units of liquid are mixed to produce a new raw material liquid, the efficiency of the concentration process decreases as the difference in concentration between the liquids increases. However, as shown in Figure 6, this decrease in efficiency becomes more pronounced as the concentration of the liquid increases.

[0104] Considering the case where equal amounts of liquids with different concentrations are mixed, the difference in the required electrolysis rate between the two points corresponding to each concentration in Figure 6 can be interpreted as an index of the decrease in efficiency of the concentration process. For example, the difference between a concentration of 93% and a concentration of 94% is small, but the difference between a concentration of 98% and a concentration of 99% is large, indicating a large decrease in efficiency.

[0105] Therefore, by narrowing the range of the high concentration, it is possible to suppress a decrease in efficiency when generating a new raw material solution by the mixing process. That is, in the embodiment, by narrowing the range of the high concentration, the concentration process can be performed more efficiently.

[0106] In the embodiment, the concentration of heavy water in the above-mentioned dilute solutions 1 to 8 is preferably 5% or more, more preferably 25% or more, and even more preferably 50% or more. These dilute solutions 1 to 8 have a lower heavy water concentration than the raw material solution used in the concentration process to produce the dilute solutions 1 to 8, but contain a higher concentration of heavy water than normal water.

[0107] Therefore, by concentrating the diluted solutions 1 to 8 having a heavy water concentration of 5% or more again as part of the raw material solution, it is possible to produce high-concentration heavy water more efficiently than by concentrating ordinary water to produce high-concentration heavy water.

[0108] If the concentration of the dilute liquid obtained as a result of the concentration process according to the embodiment is less than 5%, the process of collecting and storing the dilute liquid may be omitted, since reusing the dilute liquid may actually defeat the purpose of the concentration.

[0109] In addition, in the embodiment, from the viewpoint of promoting the purpose of concentration, the concentration of the diluted liquid to be reused is preferably 20% or more, more preferably 30% or more, 40% or more, or 50% or more. If the concentration of the diluted liquid to be reused is less than 20%, the energy loss required for reuse may exceed the loss of discarding the diluted liquid, which may be uneconomical.

[0110] In order to ensure the concentration of the above-mentioned dilute liquid, it is preferable that the initial concentration of the raw material liquid subjected to the concentration process of the embodiment be 50% or more, and further 60% or more, 70% or more, 80% or more, 85% or more, or 90% or more.

[0111] From the viewpoint of efficient concentration, the width of concentration range D is preferably within 12%, more preferably within 8%, 6%, 4%, 2%, or 1%. Similarly, the width of concentration range C is preferably within 8%, more preferably within 6%, 4%, 2%, 1%, or 0.5%.

[0112] Similarly, the width of concentration range B is preferably within 6%, more preferably within 4%, 2%, 1%, 0.5%, or 0.2%.Similarly, the width of concentration range E is preferably within 15%, more preferably within 12%, 8%, 6%, 4%, or 2%.

[0113] 7 to 9 are diagrams illustrating a specific example of the concentration process according to the embodiment. In the example of Fig. 7, first, a raw material liquid 11 having a concentration of 85.0% and a volume of 1140 L is prepared. Then, using this raw material liquid 11 as the raw material liquid, a concentration process is carried out in the concentrating device 1. As a result, a concentrated liquid 11 having a concentration of 95.0% and a volume of 488 L and a diluted liquid 11 having a concentration of 73.4% and a volume of 587 L are produced.

[0114] 7, raw liquids 12 to 15 having a concentration of 85.0% and a volume of 1140 L are prepared. These raw liquids 12 to 15 are then subjected to concentration treatment in the concentrator 1. As a result, concentrated liquids 12 to 15 having a concentration of 95.0% and a volume of 488 L and diluted liquids 12 to 15 having a concentration of 73.4% and a volume of 587 L are produced, respectively.

[0115] The concentrated solutions 11 to 15 having the same concentration range C are stored in the third tank 63 (see FIG. 1) corresponding to the concentration range C. As a result, the concentrated solutions 11 to 15 having the same concentration range C are mixed to produce a mixed solution 11 having a concentration of 95.0% and a volume of 2440 L.

[0116] Similarly, the diluted solutions 11 to 15 having the same concentration range E are stored in the fifth tank 65 (see FIG. 1) corresponding to the concentration range E. As a result, the diluted solutions 11 to 15 having the same concentration range E are mixed to produce a mixed solution 12 having a concentration of 73.4% and a volume of 2935 L.

[0117] Of the mixed solutions 11 and 12 thus produced, 1220 L of the mixed solution 11 is concentrated again in the concentrator 1, as shown in Fig. 8. This produces a concentrated solution 16 with a concentration of 96.5% and a volume of 561 L, and a diluted solution 16 with a concentration of 83.1% and a volume of 593 L.

[0118] 8, the remaining 1220 L of the mixed solution 11 is concentrated again in the concentrator 1. This produces a concentrated solution 17 with a concentration of 96.5% and a volume of 561 L, and a diluted solution 17 with a concentration of 83.1% and a volume of 593 L.

[0119] The concentrated solutions 16 and 17 having the same concentration range B are stored in the second tank 62 (see FIG. 1) corresponding to the concentration range B. As a result, the concentrated solutions 16 and 17 having the same concentration range B are mixed to produce a mixed solution 13 having a concentration of 96.5% and a volume of 1122 L.

[0120] Similarly, the diluted solutions 16 and 17 having the same concentration range D are stored in the fourth tank 64 (see FIG. 1) corresponding to the concentration range D. As a result, the diluted solutions 16 and 17 having the same concentration range D are mixed to produce a mixed solution 14 having a concentration of 83.1% and a volume of 1186 L.

[0121] Of the mixed liquid 12 produced in the example of Figure 7, 1220 L of the mixed liquid 12 is concentrated again in the concentrating device 1, as shown in Figure 9. This produces a concentrated liquid 18 with a concentration of 89.4% and a volume of 521 L, and a diluted liquid 18 with a concentration of 61.4% and a volume of 629 L.

[0122] 9, the remaining 1220 L of the mixed solution 12 is concentrated again in the concentrator 1. This produces a concentrated solution 19 with a concentration of 89.4% and a volume of 521 L, and a diluted solution 19 with a concentration of 61.4% and a volume of 629 L.

[0123] The concentrated solutions 18 and 19 having the same concentration range D are stored in the fourth tank 64 corresponding to the concentration range D. As a result, the concentrated solutions 18 and 19 having the same concentration range D are mixed to produce a mixed solution 15 having a concentration of 89.4% and a volume of 1042 L. In the present disclosure, the mixed solution 15 having the concentration range D may be further mixed with the mixed solution 14 having the same concentration range D shown in FIG.

[0124] Furthermore, the diluted solutions 18 and 19 having the same concentration range F are stored in a sixth tank 66 (see FIG. 1) corresponding to the concentration range F. As a result, the diluted solutions 18 and 19 having the same concentration range F are mixed to produce a mixed solution 16 having a concentration of 61.4% and a volume of 1258 L.

[0125] In the embodiment described so far, an example has been shown in which a mixed liquid that has been mixed once in a tank is concentrated in the concentrating device 1, but the present disclosure is not limited to such an example. For example, at least one unit of liquid among multiple units of liquid to be mixed may be sent directly to the raw liquid tank 31 of the concentrating device 1 without going through a tank.

[0126] At least a part of the mixing process may be carried out in this raw material liquid tank 31. This also allows liquids of the same concentration range to be mixed and then concentrated, so the concentration process can be carried out efficiently.

[0127] <Another embodiment> Next, a concentration system 100 according to another embodiment will be described with reference to Fig. 10. Fig. 10 is a block diagram showing an example of the configuration of the concentration system 100 according to another embodiment.

[0128] 10 includes a plurality of concentration devices 1A to 1E and a first tank 61 to a seventh tank 67. The first tank 61 to the seventh tank 67 are the same as those in the above-described embodiment, and therefore detailed description thereof will be omitted.

[0129] The concentrators 1A to 1E each have the same configuration as the concentrator 1 according to the embodiment. That is, as shown in Fig. 1, the concentrators 1A to 1E each have a concentration mechanism 10, a circulation line 20, a raw material liquid tank 31, a pump 32, a resin tower 33, a filter 34, a spare tank 36, a recovered gas storage section 52, and a recombination mechanism 54. Since these configurations are the same as those in the above-described embodiment, detailed description thereof will be omitted.

[0130] 10, the concentrating apparatus 1A has a recovery line 41A connecting the raw liquid tank 31 and the first tank 61, and a recovery line 55A connecting the recombination mechanism 54 and the third tank 63. Furthermore, the concentrating apparatus 1A has a return line 70A that returns the liquid stored in the second tank 62 to the raw liquid tank 31.

[0131] Similarly, the concentrating apparatus 1B has a recovery line 41B connecting the raw liquid tank 31 and the second tank 62, and a recovery line 55B connecting the recombination mechanism 54 and the fourth tank 64. Furthermore, the concentrating apparatus 1B has a return line 70B that returns the liquid stored in the third tank 63 to the raw liquid tank 31.

[0132] Similarly, the concentrating apparatus 1C has a recovery line 41C connecting the raw liquid tank 31 and the third tank 63, and a recovery line 55C connecting the recombination mechanism 54 and the fifth tank 65. Furthermore, the concentrating apparatus 1C has a return line 70C that returns the liquid stored in the fourth tank 64 to the raw liquid tank 31.

[0133] Similarly, the concentrating apparatus 1D has a recovery line 41D connecting the raw liquid tank 31 and the fourth tank 64, and a recovery line 55D connecting the recombination mechanism 54 and the sixth tank 66. Furthermore, the concentrating apparatus 1D has a return line 70D that returns the liquid stored in the fifth tank 65 to the raw liquid tank 31.

[0134] Similarly, the concentrating apparatus 1E has a recovery line 41E connecting the raw liquid tank 31 and the fifth tank 65, and a recovery line 55E connecting the recombination mechanism 54 and the seventh tank 67. Furthermore, the concentrating apparatus 1E has a return line 70E that returns the liquid stored in the sixth tank 66 to the raw liquid tank 31.

[0135] Here, in a concentration system 100 according to another embodiment, a plurality of concentration devices 1A to 1E correspond to different concentration ranges, and concentrate only the raw material liquid in the corresponding concentration range.

[0136] For example, the concentrating device 1A concentrates only the raw material liquid having a concentration range B. In this case, for example, the mixed liquid having a concentration range B stored in the second tank 62 is returned to the concentrating device 1A through the return line 70A, and the mixed liquid is concentrated by the concentrating device 1A.

[0137] The concentrated solution of concentration range A produced by this concentration process passes through recovery line 41A and is stored in first tank 61. The diluted solution of concentration range C produced by this concentration process passes through recovery line 55A and is stored in third tank 63.

[0138] Furthermore, the concentrating device 1B concentrates only the raw material liquid having a concentration range C. In this case, for example, the mixed liquid having a concentration range C stored in the third tank 63 is returned to the concentrating device 1B through the return line 70B, and the mixed liquid is concentrated by the concentrating device 1B.

[0139] The concentrated solution of concentration range B produced by this concentration process passes through recovery line 41B and is stored in second tank 62. The diluted solution of concentration range D produced by this concentration process passes through recovery line 55B and is stored in fourth tank 64.

[0140] Furthermore, the concentrating device 1C concentrates only the raw material liquid having a concentration range D. In this case, for example, the mixed liquid having a concentration range D stored in the fourth tank 64 is returned to the concentrating device 1C through a return line 70C, and the mixed liquid is concentrated by the concentrating device 1C.

[0141] The concentrated solution of concentration range C produced by this concentration process passes through recovery line 41C and is stored in third tank 63. The diluted solution of concentration range E produced by this concentration process passes through recovery line 55C and is stored in fifth tank 65.

[0142] Furthermore, the concentrating device 1D concentrates only the raw material liquid having a concentration range E. In this case, for example, the mixed liquid having a concentration range E stored in the fifth tank 65 is returned to the concentrating device 1D through a return line 70D, and the mixed liquid is concentrated by the concentrating device 1D.

[0143] The concentrated solution of concentration range D produced by this concentration process passes through recovery line 41D and is stored in fourth tank 64. The diluted solution of concentration range F produced by this concentration process passes through recovery line 55D and is stored in sixth tank 66.

[0144] Furthermore, the concentrating device 1E concentrates only the raw material liquid having a concentration range F. In this case, for example, the mixed liquid having a concentration range F stored in the sixth tank 66 is returned to the concentrating device 1E through a return line 70E, and the mixed liquid is concentrated by the concentrating device 1E.

[0145] The concentrated solution of concentration range E produced by this concentration process passes through recovery line 41E and is stored in fifth tank 65. The diluted solution of concentration range G produced by this concentration process passes through recovery line 55E and is stored in seventh tank 67.

[0146] As described above, in another embodiment, different concentrators 1A to 1E are provided for each individual concentration range, so that the parameters of the concentration process for each of the concentrators 1A to 1E can be optimized according to the concentration range. Therefore, according to this another embodiment, the concentration process can be performed more efficiently.

[0147] In another embodiment, an example is shown in which the mixed liquid that has been mixed once in the tank is concentrated in each concentrating device, but the present disclosure is not limited to such an example. For example, at least one unit of liquid among multiple units of liquid to be mixed may be sent directly to the raw liquid tank 31 of the concentrating device without going through a tank.

[0148] At least a part of the mixing process may be carried out in this raw material liquid tank 31. This also allows liquids of the same concentration range to be mixed and then concentrated, so the concentration process can be carried out efficiently.

[0149] In the above embodiments, the concentration process for concentrating heavy water contained in the raw material solution is efficiently performed, but the present disclosure is not limited to such examples, and the technology of the present disclosure may be applied to a process for concentrating a component other than heavy water. This also allows the concentration process to be performed efficiently.

[0150] The concentration method according to the embodiment includes a first concentration step, a first mixing step, and a second concentration step. The first concentration step concentrates a specific component (heavy water) contained in a liquid (raw material liquid 1) having a first concentration range (concentration range D) for the specific component (heavy water) to produce a first concentrated liquid (concentrated liquid 1) having a second concentration range (concentration range C) higher than the first concentration range (concentration range D). The first mixing step mixes the first concentrated liquid (concentrated liquid 1) obtained in the first concentration step with another liquid (raw material liquid 2) having the second concentration range. The second concentration step concentrates the specific component (heavy water) contained in the mixed liquid (mixed liquid 1) obtained in the first mixing step to produce a second concentrated liquid (concentrated liquid 2) having a third concentration range (concentration range B) higher than the second concentration range (concentration range C). This allows the concentration process to be carried out efficiently.

[0151] The concentration method according to the embodiment includes a distribution step, a second mixing step, and a third concentration step. The distribution step distributes a liquid (raw material liquid 1) having a first concentration range (concentration range D) of a specific component (heavy water) into a first concentrated liquid (concentrated liquid 1) having a second concentration range (concentration range C) higher than the first concentration range (concentration range D) and a first dilute liquid (dilute liquid 1) having a fourth concentration range (concentration range E) lower than the first concentration range (concentration range D). The second mixing step mixes the first dilute liquid (dilute liquid 1) obtained in the distribution step with another liquid (raw material liquid 3) having the fourth concentration range (concentration range E). The third concentration step concentrates the specific component (heavy water) contained in the mixed liquid (mixed liquid 2) obtained in the second mixing step to produce a liquid (concentrated liquid 3) having the first concentration range (concentration range D). This allows the concentration process to be performed efficiently.

[0152] The concentration method according to the embodiment includes a distribution step, a first mixing step, a second concentration step, a third concentration step, and a third concentration step. The distribution step distributes a liquid (raw material liquid 1) having a first concentration range (concentration range D) of a specific component (heavy water) into a first concentrated liquid (concentrated liquid 1) having a second concentration range (concentration range C) higher than the first concentration range (concentration range D), and a first dilute liquid (dilute liquid 1) having a fourth concentration range (concentration range E) lower than the first concentration range (concentration range D). The first mixing step mixes the first concentrated liquid (concentrated liquid 1) obtained in the distribution step with another liquid (raw material liquid 2) having the second concentration range (concentration range C). The second concentration step concentrates a specific component (heavy water) contained in the mixture (mixture 1) obtained in the first mixing step to produce a second concentrated liquid (concentrated liquid 2) having a third concentration range (concentration range B) higher than the second concentration range (concentration range C). The second mixing step mixes the first diluted liquid (dilute liquid 1) obtained in the distribution step with another liquid (raw material liquid 3) having a fourth concentration range (concentration range E). The third concentration step concentrates a specific component (heavy water) contained in the mixture (mixture 2) obtained in the second mixing step to produce a liquid (concentrated liquid 3) having the first concentration range (concentration range D). This allows the concentration process to be performed efficiently.

[0153] In the concentration method according to the embodiment, the width of the second concentration range (concentration range C) is within 6%, which allows the concentration process to be carried out efficiently.

[0154] Furthermore, in the concentration method according to the embodiment, the first mixing step is carried out inside the concentration device 1 that concentrates the specific component (heavy water) contained in the liquid. This allows the concentration process to be carried out efficiently.

[0155] Furthermore, in the concentration method according to the embodiment, the second mixing step is carried out inside the concentration device 1 that concentrates the specific component (heavy water) contained in the liquid. This allows the concentration process to be carried out efficiently.

[0156] In the concentration method according to the embodiment, the first concentration step or distribution step is performed in a first concentration device (concentration device 1C) that concentrates a specific component (heavy water) contained in the liquid. The second concentration step is performed in a second concentration device (concentration device 1B) that concentrates a specific component (heavy water) contained in the liquid. This allows the concentration process to be carried out more efficiently.

[0157] In the concentration method according to the embodiment, the distribution step is performed in a first concentration device (concentration device 1C) that concentrates a specific component (heavy water) contained in the liquid. The third concentration step is performed in a third concentration device (concentration device 1D) that concentrates a specific component (heavy water) contained in the liquid. This allows the concentration process to be carried out more efficiently.

[0158] Furthermore, in the concentration method according to the embodiment, the width of the second concentration range (concentration range C) is narrower than the width of the first concentration range (concentration range D), and the width of the third concentration range (concentration range B) is narrower than the width of the second concentration range (concentration range C). This allows the concentration process to be carried out more efficiently.

[0159] Furthermore, in the concentration method according to the embodiment, the width of the second concentration range (concentration range C) is narrower than the width of the first concentration range (concentration range D), which is narrower than the width of the fourth concentration range (concentration range E). This allows the concentration process to be carried out more efficiently.

[0160] In the concentration method according to the embodiment, the concentration of the specific component (heavy water) in the first dilute liquid (dilute liquid 1) is 5% or more, which allows for efficient production of highly concentrated heavy water.

[0161] 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.

[0162] For example, in terms of heavy water enrichment, the heavy water enrichment method of the present disclosure is not limited to electrolysis, but can also be applied to gas phase exchange reaction, liquid hydrogen separation, distillation, double temperature exchange, etc. Furthermore, in addition to heavy water enrichment, the present disclosure can also be applied to separation and enrichment of isotope atoms other than hydrogen.

[0163] Furthermore, the present disclosure can be preferably applied to mixtures that are difficult to separate, such as mixtures of isotopes of atoms, particularly mixtures of substances with similar physical or chemical properties, etc. According to the present disclosure, it is possible to not only selectively concentrate only a specific substance from such a mixture, but also to separate two or more substances with high purity.

[0164] Although the present disclosure is preferably carried out in a volume reduction system (batch system), the entire series of concentration steps is not limited to this. For example, a continuous system may be used temporarily or locally in the series of steps.

[0165] While the present disclosure has been described above in terms of obtaining a concentrated liquid, it is not intended to exclude the purpose of obtaining a diluted liquid, which can also be achieved by applying the above-described steps in a similar manner.

[0166] 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]

[0167] 1, 1A~1E Concentrator 10 Concentration mechanism 20 Circulation Line 31 Raw material liquid tank 52 Recovered gas storage section 54 Recombination mechanism 61 First Tank 62 Second Tank 63 Third Tank 64 4th Tank 65 5th Tank 66 6th Tank 67 7th Tank 100 Concentration System

Claims

1. a first concentration step of concentrating a specific component contained in a liquid having a first concentration range with respect to the specific component to produce a first concentrated liquid having a second concentration range higher than the first concentration range; a first mixing step of mixing the first concentrated liquid obtained in the first concentration step with another liquid having the second concentration range; a second concentration step of concentrating the specific component contained in the mixed solution obtained in the first mixing step to produce a second concentrated liquid having a third concentration range higher than the second concentration range; A concentration method comprising:

2. a distributing step of distributing a liquid having a first concentration range with respect to a specific component into a first concentrated liquid having a second concentration range higher than the first concentration range and a first dilute liquid having a fourth concentration range lower than the first concentration range; a second mixing step of mixing the first diluted liquid obtained in the distributing step with another liquid having the fourth concentration range; a third concentration step of concentrating the specific component contained in the mixed solution obtained in the second mixing step to produce a liquid having the first concentration range; A concentration method comprising:

3. a distributing step of distributing a liquid having a first concentration range with respect to a specific component into a first concentrated liquid having a second concentration range higher than the first concentration range and a first dilute liquid having a fourth concentration range lower than the first concentration range; a first mixing step of mixing the first concentrated liquid obtained in the distributing step with another liquid having the second concentration range; a second concentration step of concentrating the specific component contained in the mixed solution obtained in the first mixing step to produce a second concentrated liquid having a third concentration range higher than the second concentration range; a second mixing step of mixing the first diluted liquid obtained in the distributing step with another liquid having the fourth concentration range; a third concentration step of concentrating the specific component contained in the mixed solution obtained in the second mixing step to produce a liquid having the first concentration range; A concentration method comprising:

4. The width of the second concentration range is within 6%. The method for concentrating according to any one of claims 1 to 3.

5. The first mixing step is carried out inside a concentrating device that concentrates the specific component contained in the liquid. The concentration method according to claim 1 or 3.

6. The second mixing step is carried out inside a concentrating device that concentrates the specific component contained in the liquid. The concentration method according to claim 2 or 3.

7. the first concentration step is carried out in a first concentration device that concentrates the specific component contained in the liquid; The second concentration step is carried out in a second concentration device that concentrates the specific component contained in the liquid. The concentration method according to claim 1.

8. The distributing step is carried out in a first concentrating device that concentrates the specific component contained in the liquid, The second concentration step is carried out in a second concentration device that concentrates the specific component contained in the liquid. The concentration method according to claim 3.

9. The distributing step is carried out in a first concentrating device that concentrates the specific component contained in the liquid, The third concentration step is carried out in a third concentration device that concentrates the specific component contained in the liquid. The concentration method according to claim 2 or 3.

10. the width of the second concentration range is narrower than the width of the first concentration range; The width of the third concentration range is narrower than the width of the second concentration range. The concentration method according to claim 1 or 3.

11. the width of the second concentration range is narrower than the width of the first concentration range; The width of the first concentration range is narrower than the width of the fourth concentration range. The concentration method according to claim 2 or 3.

12. The concentration of the specific component in the first diluted liquid is 5% or more. The concentration method according to claim 2 or 3.

Images