Concentration method and purification method

Abstract

To provide a technology capable of properly performing concentration processing again using newly introduced raw material water.SOLUTION: A concentration method includes a concentration step, a recombination step, and a neutralization step. In the concentration step, heavy water contained in a first liquid is concentrated. In the recombination step, deuterium gas generated in the concentration step is combined with oxygen to produce a second liquid containing heavy water. In the neutralization step, the pH of the second liquid produced in the recombination step is brought closer to neutral to obtain a third liquid.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] Disclosed embodiments relate to concentration and purification methods. [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] When producing highly concentrated heavy water using electrolysis, the hydrogen and deuterium gases generated by electrolysis can be recombined with oxygen to produce new raw water with a lower heavy water concentration than the raw water. However, with conventional technology, this new raw water is often simply combined with the raw water and reused, without consideration of further purification via recombination. Furthermore, while a hydrogen burner is sometimes used for recombination, the possibility of contamination of the raw water caused by using a hydrogen burner was not taken into account.

[0006] The present disclosure has been made in view of the above, and provides a technique that allows for a satisfactory concentration process when a concentration process is performed again using new raw water. [Means for solving the problem]

[0007] A concentration method according to one embodiment of the present disclosure includes a concentration step, a recombination step, and a neutralization step. The concentration step concentrates heavy water contained in a first liquid. The recombination step combines deuterium gas generated in the concentration step with oxygen to produce a second liquid containing heavy water. The neutralization step adjusts the pH of the second liquid produced in the recombination step to approach neutrality to obtain a third liquid. [Effects of the Invention]

[0008] According to the present disclosure, when a concentration process is performed again using new raw water, the concentration process can be performed satisfactorily. [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 illustrating an example of a procedure for a diluted solution generation process according to the embodiment. [Figure 5] FIG. 5 is a flowchart showing another example of the procedure of the diluted solution generating process according to the embodiment. [Figure 6] FIG. 6 is a flowchart showing an example of a procedure for the purification process according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the concentration method and purification 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 dimensional relationships and ratios may differ between the drawings.

[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 a separate system from the circulation line 20 and the supply line 35, is connected to the raw material liquid tank 31. The recovery line 41 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 Figures 3 to 5. Figure 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) described so far, the control unit of the concentrating device 1 performs a diluted liquid production process (step S103). Details of this diluted liquid production process will be described later.

[0045] Next, the control unit of the concentrating device 1 determines whether the concentration process (step S102) has been completed (step S104). For example, when the process of step S102 has been performed continuously for a predetermined time, the control unit can determine that the raw material liquid has been concentrated to a desired concentration and that the concentration process has been completed.

[0046] In the present disclosure, the process of step S104 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.

[0047] Then, if it is determined that the concentration process has been completed (step S104, 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 S105), and ends the series of concentration processes.

[0048] In this concentrated liquid recovery process, the control unit stores the concentrated liquid recovered from the raw material liquid tank 31, the circulation line 20, etc. in the concentrated liquid tank 42 (see FIG. 1). On the other hand, if it is determined that the concentration process has not been completed (No in step S104), the process returns to steps S102 and S103.

[0049] 4 is a flowchart showing an example of a procedure for a diluted liquid production process according to the embodiment. In the diluted liquid production process according to the embodiment, first, the control unit of the concentrating device 1 (see FIG. 1) performs a gas recovery process for recovering gas generated in the concentrating mechanism 10 (see FIG. 1) (step S201).

[0050] 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 (see FIG. 1).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).

[0051] Next, the control unit performs a recombination process in which the recovered hydrogen gas and deuterium gas are recombined with oxygen in the recombination mechanism 54 (see FIG. 1) to produce an aqueous solution containing water and heavy water (step S202).

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] In the embodiment, in the process of step S202, when hydrogen gas and deuterium gas are recombined using a hydrogen burner, NO is added to the generated diluted solution. x (Nitrogen oxides) may be mixed in.

[0057] The cause of this is unclear, but it is thought that N2 present in the air is oxidized during the recombination process, and some of it dissolves in the diluted solution. x In dilute solutions, NO such as nitric acid (HNO3) or nitrous acid (HNO2) x The dilution solution is HNO x However, unless otherwise specified in this specification, NO x and NOx NO in diluted solution without distinguishing between derived substances x In that case, NO x It also refers to the product of its origin.

[0058] The diluted solution produced contains NO x When this dilute solution is mixed in, it becomes strongly acidic, and if this dilute solution is used again in the concentrating device 1, the concentrating mechanism 10, the circulation line 20, etc. may be altered by the strongly acidic dilute solution, which may cause problems in the concentration process.

[0059] Therefore, in the dilute solution generation process according to the embodiment, following the recombination process (step S202), a neutralization process is performed (step S203) to bring the pH of the dilute solution generated by the recombination mechanism 54 closer to neutral to obtain a neutralized dilute solution. The neutralized dilute solution is an example of the third liquid.

[0060] This prevents the concentration mechanism 10, circulation line 20, etc. from being altered by the strongly acidic dilute solution, so that when the concentration process is performed again using the neutralized dilute solution, the concentration process can be performed smoothly.

[0061] The neutralization process according to the embodiment may be performed, for example, by mixing an alkaline chemical solution with the diluted solution generated by the recombination mechanism 54. This allows the pH of the diluted solution to approach neutrality in a simple manner.

[0062] In addition, the neutralization treatment according to the embodiment may be carried out by removing, for example, components that change the pH, such as NO x This may be achieved by removing impurities from the diluted solution, which may adversely affect the concentration mechanism 10 and the like, thereby further preventing problems from occurring in the concentration mechanism 10 and the like.

[0063] Therefore, according to the embodiment, when the concentration process is carried out again using the neutralized diluted solution, the concentration process can be carried out more satisfactorily.

[0064] Furthermore, pH control or NOx Instead of selectively removing impurities, a process for lowering the conductivity of the dilute solution may be performed. Generally, if the conductivity of the neutralized dilute solution is set to 1 μS / cm or less, most of the impurities will be removed and the neutralization process can be achieved. The conductivity of the neutralized dilute solution is preferably 1 μS / cm or less, more preferably 0.1 μS / cm or less, and even more preferably 0.05 μS / cm or less.

[0065] In the present disclosure, the treatment for lowering the conductivity may be performed independently of the pH control, or the pH control and the treatment for lowering the conductivity may be performed sequentially or in parallel. The treatment for lowering the conductivity is preferred because it can suppress deterioration of the concentrating mechanism 10 and the like.

[0066] In addition, the components that cause pH fluctuations in the diluted solution are NO x The dilute solution produced by the recombination process is not limited to being acidic due to the components that change the pH, but may also contain various impurities that change the pH of the dilute solution.

[0067] As a means for removing components that change the pH from the dilute solution, for example, the dilute solution may be treated with an ion exchange resin or an ion exchange membrane, which allows components that change the pH to be easily removed from the dilute solution.

[0068] These ion exchange resins and ion exchange membranes may be composed of only a material that exchanges anions, may be composed of only a material that exchanges cations, or may be composed of a material that exchanges anions and a material that exchanges cations.

[0069] For example, ion exchange resins and ion exchange membranes are made of only materials that exchange anions, so NO x Furthermore, since the ion exchange resin and the ion exchange membrane are made of a material that exchanges anions and a material that exchanges cations, a wide variety of impurities can be efficiently removed.

[0070] The neutralization process according to the embodiment can be carried out, for example, by mixing the diluted solution produced in the recombination process with an ion exchange resin in a tank and reacting the diluted solution with the ion exchange resin. The diluted solution and the ion exchange resin may be reacted while injecting air into the tank using a compressor or the like. This allows the neutralization process to be carried out efficiently.

[0071] In addition, in the embodiment, the pH of the neutralized dilute solution is preferably set to 3 or more and 9 or less, more preferably 5 or more and 8 or less, and even more preferably 6 or more and 7.5 or less by the neutralization treatment. This further prevents deterioration of the concentration mechanism 10, etc., and therefore, when a concentration treatment is performed again using the neutralized dilute solution, this concentration treatment can be performed more efficiently.

[0072] In addition, in an embodiment, the neutralized dilute solution obtained by the neutralization process may be used as at least a part of the raw material liquid, and the concentration process may be performed again. That is, in the raw material liquid preparation process (step S101) shown in FIG. 3, the neutralized dilute solution obtained by the neutralization process (step S203) may be used as at least a part of the raw material liquid.

[0073] This neutralized dilute solution has a lower heavy water concentration than the raw material solution used in the concentration process to produce the neutralized dilute solution, but contains heavy water at a higher concentration than normal water. Therefore, by concentrating the neutralized dilute solution again, high-concentration heavy water can be produced more efficiently than by concentrating normal water to produce high-concentration heavy water.

[0074] 5 is a flowchart showing another example of the procedure of the diluted liquid production process according to the embodiment. In the diluted liquid production process according to the embodiment, first, the control unit of the concentrating device 1 (see FIG. 1) performs a gas recovery process to recover the gas generated in the concentrating mechanism 10 (see FIG. 1) (step S301).

[0075] Next, the control unit performs a recombination process in which the recovered hydrogen gas and deuterium gas are recombined with oxygen in the recombination mechanism 54 (see FIG. 1) to produce an aqueous solution containing water and heavy water (step S302). The processes in steps S301 and S302 are similar to the processes in steps S201 and S202 described above, and therefore detailed description thereof will be omitted.

[0076] Next, the control unit extracts NO from the diluted solution produced by the recombination mechanism 54. x A removal process is performed to remove NO and obtain a diluted solution (step S303). x is an example of a contaminant, and the removal diluent is another example of a third liquid.

[0077] This means NO x Since the dilute solution that has become strongly acidic can be prevented from altering the concentration mechanism 10, the circulation line 20, etc., when the concentration process is performed again using the removed dilute solution, this concentration process can be performed smoothly.

[0078] In the embodiment, the removal process is performed to remove NOx that adversely affects the concentration mechanism 10 and the like. x Since the ions themselves are removed from the diluted solution, malfunctions in the concentration mechanism 10 and the like can be further suppressed.

[0079] NO from dilute solution x As a means for removing NO, for example, the diluted solution may be treated with an ion exchange resin or an ion exchange membrane. x can be easily removed.

[0080] These ion exchange resins and ion exchange membranes may be composed of only anion-exchanging materials, or may be composed of anion-exchanging materials and cation-exchanging materials. In this way, when the ion exchange resins and ion exchange membranes contain anion-exchanging materials, NO x can be efficiently removed.

[0081] The removal process according to the embodiment can be carried out, for example, by mixing the diluted solution produced in the recombination process with an ion exchange resin in a tank and causing the diluted solution to react with the ion exchange resin. In this case, the diluted solution may be reacted with the ion exchange resin while injecting air into the tank using a compressor or the like. This allows the NO x The removal process can be carried out efficiently.

[0082] Furthermore, in the embodiment, the pH of the dilute solution produced by the recombination mechanism 54 through the removal process is preferably set to 3 or more and 9 or less, more preferably 5 or more and 8 or less, and even more preferably 6 or more and 7.5 or less. This further prevents deterioration of the concentration mechanism 10 and the like, so that when the removed dilute solution is used to perform the concentration process again, the concentration process can be performed more efficiently.

[0083] In addition, in the embodiment, the removed diluted solution obtained by the removal process may be used as at least a part of the raw material liquid, and the concentration process may be performed again. That is, in the raw material liquid preparation process (step S101) shown in FIG. 3, the removed diluted solution obtained by the removal process (step S303) may be used as at least a part of the raw material liquid.

[0084] This allows highly concentrated heavy water to be produced more efficiently than by producing highly concentrated heavy water by concentrating ordinary water.

[0085] In the above embodiment, NO is an example of a contaminant that may be mixed into the diluted solution. x However, the present disclosure is not limited to such an example, and the removal process may be carried out x This also allows the concentration treatment to be carried out satisfactorily when the concentration treatment is carried out again using the diluted solution from which the contaminants were removed.

[0086] As mentioned above, when at least one of hydrogen and deuterium is combined with oxygen in air, NO x This may occur. xThe inventors have found that NO is not only released into the atmosphere but also partly mixed into the bound water. This fact indicates that the use of a hydrogen burner is x This means that harmful bound water containing hydroxybenzoates may be generated, which may cause an environmental burden. The present disclosure is also useful for reducing such an environmental burden.

[0087] 6 is a flowchart showing an example of the procedure of the purification process according to the embodiment. In the purification process according to the embodiment, first, an operator or the like performs a binding process in which at least one of hydrogen and deuterium is bound to oxygen in the air to generate bound water containing at least one of water and heavy water (step S401).

[0088] Next, the worker or the like separates the air-borne NO from the bound water generated in the process of step S401. x This reduces the environmental impact of bound water (step S402).

[0089] NO from bound water x As a means for removing NO, for example, the bound water may be treated with an ion exchange resin or may be treated with an ion exchange membrane. x can be easily removed.

[0090] These ion exchange resins and ion exchange membranes may be composed of only anion-exchanging materials, or may be composed of anion-exchanging materials and cation-exchanging materials. In this way, when the ion exchange resins and ion exchange membranes contain anion-exchanging materials, NO x can be efficiently removed.

[0091] The removal process according to the embodiment can be carried out, for example, by mixing the bound water produced in the binding process with an ion exchange resin in a tank and causing the bound water to react with the ion exchange resin. In this case, the bound water may be reacted with the ion exchange resin while injecting air into the tank using a compressor or the like. This allows the NOx The removal process can be carried out efficiently.

[0092] In addition, in an embodiment, the removal treatment may be performed to adjust the pH of the bound water generated in the binding treatment to between 3 and 9, preferably between 5 and 8, and even more preferably between 6 and 7.5. This further reduces the environmental impact of bound water.

[0093] In accordance with the above purification process, it is also preferable to provide a bound water purification device when using a hydrogen burner. The purification device includes, for example, a collection unit for collecting bound water and a unit for extracting NO from the collected bound water. x and a removal unit that removes the hydrogen from the burner. The collection unit may include a funnel, a gutter, or a water tank that is provided below the hydrogen burner, particularly directly below the burner flame. The removal means in the removal mechanism can be the same as those used in the removal step described above. A hydrogen burner with a purification function that is equipped with such a purification device is also included in the present disclosure.

[0094] The concentration method according to the embodiment includes a concentration step (step S102), a recombination step (step S202), and a neutralization step (step S203). The concentration step (step S102) concentrates the heavy water contained in the first liquid (raw material liquid). The recombination step (step S202) combines the deuterium gas generated in the concentration step with oxygen to produce a second liquid (dilute liquid) containing heavy water. The neutralization step (step S203) adjusts the pH of the second liquid (dilute liquid) produced in the recombination step (step S202) to approach neutrality to produce a third liquid (neutralized dilute liquid). This allows the concentration process to be carried out successfully when the neutralized dilute liquid is used to perform another concentration process.

[0095] The concentration method according to the embodiment further includes a re-concentration step of concentrating the heavy water contained in the third liquid (neutralized dilute liquid), thereby enabling highly concentrated heavy water to be produced efficiently.

[0096] Furthermore, in the concentration method according to the embodiment, the neutralization step (step S203) removes components that change the pH from the second liquid (dilute liquid), which further prevents problems from occurring in the concentration mechanism 10 and the like.

[0097] In the concentration method according to the embodiment, the neutralization step (step S203) is performed by removing NO from the second liquid (dilute liquid). x This can further prevent problems from occurring in the concentration mechanism 10 and the like.

[0098] In the concentration method according to the embodiment, the neutralization step (step S203) involves treating the second liquid (dilute solution) with an ion exchange resin, which allows components that change the pH to be easily removed from the dilute solution.

[0099] In the concentration method according to the embodiment, the neutralization step (step S203) treats the second liquid (dilute solution) with an ion exchange membrane, which makes it possible to easily remove components that change the pH from the dilute solution.

[0100] The concentration method according to the embodiment includes a concentration step (step S102), a recombination step (step S302), and a removal step (step S303). The concentration step (step S102) concentrates the heavy water contained in the first liquid (raw material liquid). The recombination step (step S302) combines the deuterium gas generated in the concentration step with oxygen to remove the heavy water and the impurities (NO x The removal step (step S303) removes impurities (NO ) from the second liquid (dilute liquid) generated in the recombination step (step S302). x ) is removed to obtain a third liquid (removed dilute solution). This allows the concentration process to be carried out well when the removed dilute solution is used for another concentration process.

[0101] The purification method according to the embodiment also includes a combining step (step S401) and a removing step (step S402). The combining step (step S401) combines at least one of hydrogen and deuterium with oxygen in the air to generate bound water containing at least one of water and heavy water. The removing step (step S402) removes air-derived NO from the bound water generated in the combining step (step S401). x This reduces the environmental impact caused by bound water.

[0102] 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.

[0103] 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]

[0104] 1 Concentrator 10 Concentration mechanism 20 Circulation Line 31 Raw material liquid tank 32 Pump 33 Resin Tower 34 Filters 42 Concentrate tank 52 Recovered gas storage section 54 Recombination mechanism 56 Dilute Liquid Tank

Claims

1. a concentration step of concentrating heavy water contained in the first liquid; a recombination step of combining the deuterium gas generated in the concentration step with oxygen to produce a second liquid containing heavy water; a neutralization step of adjusting the pH of the second liquid produced in the recombination step to approach neutral to obtain a third liquid; A concentration method comprising:

2. a re-concentration step of concentrating the heavy water contained in the third liquid. The concentration method according to claim 1.

3. The neutralization step removes components that change the pH from the second liquid. The concentration method according to claim 1 or 2.

4. The neutralization step is performed by removing NO from the second liquid. ｘ Remove The concentration method according to claim 3.

5. The neutralization step includes treating the second liquid with an ion exchange resin. The concentration method according to claim 3.

6. The neutralization step includes treating the second liquid with an ion exchange membrane. The concentration method according to claim 3.

7. a concentration step of concentrating heavy water contained in the first liquid; a recombination step in which the deuterium gas generated in the concentration step is combined with oxygen to produce a second liquid containing heavy water and impurities; a removing step of removing the contaminants from the second liquid produced in the recombination step to obtain a third liquid; A concentration method comprising:

8. a bonding step of bonding at least one of hydrogen and deuterium with oxygen in air to generate bound water containing at least one of water and heavy water; The air-derived NO ｘ a removal step of removing A purification method comprising:

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