Chemical species separation device and chemical species separation method

Abstract

To provide a chemical species separation device and chemical species separation method capable of separating chemical species with higher purity at a low operational cost.SOLUTION: A chemical species separation device is the chemical species separation device which separates mixed gases for each chemical species and includes: a chamber in which a space is formed; a separation unit which is made of a metallic material that allows tritium and light hydrogen to pass therethrough with a speed difference and divides the space in each chamber into a first region and a second region; a gas flow path which has a supply unit for supplying mixed gas to the first region and a discharge unit for directing the chemical species separated from the second region to the outside; and a pressure adjustment unit which adjusts the pressure in the first region to be higher than that in the second region. Each chamber and the separation unit are detachable from the gas flow path.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a chemical species separation device and a chemical species separation method. [Background technology]

[0002] Since tritium-containing water is radioactive, various technologies have been proposed for the purpose of safely treating it. For example, in the device according to the following Patent Document 1, it is said that it is possible to separate tritium and hydrogen by electrolyzing raw water to obtain a mixed gas containing tritium and hydrogen and then permeating the mixed gas through an alloy membrane. In other words, it is said that it is possible to absorb most of the tritium into the alloy membrane based on the difference in permeation speed between tritium and hydrogen. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-100090 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, there has been little research on how to treat alloy membranes that have absorbed tritium. In addition, because alloy membranes generally contain expensive metals, there has been a demand for cheaper and more efficient methods and equipment for separating tritium from them, in order to reduce the operating and maintenance costs of the equipment.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a chemical species separation device and a chemical species separation method that are capable of separating chemical species with higher purity at low operating costs. [Means for solving the problem]

[0006] In order to solve the above problems, the chemical species separation device according to the present disclosure is a chemical species separation device that separates a mixed gas containing tritium and hydrogen into chemical species, and includes a chamber having a space formed therein, a separation unit formed of a metal material through which the tritium and the hydrogen can permeate at different speeds and that divides the space within the chamber into a first region and a second region, a gas flow path having a supply unit that supplies the mixed gas to the first region and an exhaust unit that leads the separated chemical species from the second region to the outside, and a pressure adjustment unit that adjusts the pressure in the first region to be higher than the pressure in the second region, and each of the chambers and the separation unit is detachable from the gas flow path.

[0007] A chemical species separation method according to the present disclosure is a chemical species separation method using the above-mentioned chemical species separation device, and the following steps are sequentially performed for a plurality of chambers and a plurality of separation sections: supplying the mixed gas to the first region by the supply unit; increasing the pressure of the first region by the pressure adjustment unit; recovering from the second region the light hydrogen that has permeated the separation section as a result of the increased pressure; removing the chamber and the separation section from the gas flow path when adsorption of the tritium by the separation section is completed; recovering the tritium from the removed separation section; and reinstalling the other chamber and separation section in the gas flow path after the tritium has been recovered. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a chemical species separation device and a chemical species separation method capable of separating chemical species with higher purity at low operating costs. [Brief description of the drawings]

[0009] [Figure 1] 1 is an overall view showing a configuration of a chemical species separation device according to an embodiment of the present disclosure. [Diagram 2] 2 is a schematic cross-sectional view showing a configuration of a chamber and a separation unit according to an embodiment of the present disclosure. FIG. [Diagram 3] 1 is a flow chart illustrating steps of a chemical species separation method according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is an explanatory diagram showing the state of a chamber and a separation unit in a gas supply step of a chemical species separation method according to an embodiment of the present disclosure. [Diagram 5] FIG. 2 is an explanatory diagram showing the state of a chamber and a separation unit in a pressurized separation step of a chemical species separation method according to an embodiment of the present disclosure. [Figure 6] FIG. 2 is an explanatory diagram showing the state of a chamber and a separation unit in a light hydrogen recovery step of the chemical species separation method according to the embodiment of the present disclosure. [Figure 7] FIG. 1 is an explanatory diagram showing the state of a chamber and a separation unit in a tritium recovery step of a chemical species separation method according to an embodiment of the present disclosure. [Figure 8] 1 is a graph showing the permeation rates of tritium, deuterium, and hydrogen through a palladium alloy. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a chemical species separation device 1 and a chemical species separation method according to an embodiment of the present disclosure will be described with reference to FIGS.

[0011] (Configuration of chemical species separation device) The chemical species separation device 1 is a device that separates a mixed gas containing, for example, hydrogen, deuterium, and tritium into these chemical species. In the following, the configuration of the device will be described typically using a mixed gas containing hydrogen and tritium as an example.

[0012] 1, the chemical species separation device 1 includes a plurality of device bodies 10, a gas flow path 20, a gas supply source 30 (supply section), and a light hydrogen recovery section 40. A separation section 12 made of a metal material is disposed within the device body 10. As will be described in detail later, separation of the mixed gas into individual chemical species is performed by passing the mixed gas through this separation section 12.

[0013] The gas flow path 20 has a supply flow path 21, a plurality of branch flow paths 22, and a recovery flow path 23. A gas supply source 30 is connected to the upstream side of the supply flow path 21. Although not shown in detail, in the gas supply source 30, water containing tritium is electrolyzed to generate and store a mixed gas containing tritium and light hydrogen. The branch flow paths 22 are branched into a plurality of paths from the downstream end of the supply flow path 21. One device main body 10 is connected to each branch flow path 22. A recovery flow path 23 is connected to the downstream side of each device main body 10. A tank or a cylinder serving as a light hydrogen recovery unit 40 is connected to the downstream end of the recovery flow path 23.

[0014] As shown in FIG. 2, the device body 10 has a chamber 11, a separation section 12, and a pressure adjustment section 13. The chamber 11 is cylindrical. The separation section 12 is provided in the chamber 11. The separation section 12 separates hydrogen and tritium based on the difference in permeation speed between these chemical species. The separation section 12 is formed of a metal material having such permeation characteristics. Specifically, as this type of metal material, an alloy containing at least one chemical species selected from a group including palladium, vanadium, tantalum, niobium, and nickel is used. The separation section 12 divides the space in the chamber 11 into two. The upstream side of the separation section 12 (i.e., the side to which the branch flow path 22 is connected) is defined as a first region V1. The region opposite the first region V1 across the separation section 12 is defined as a second region V2.

[0015] The pressure adjusting unit 13 can compress the mixed gas supplied into the first region V1 to pressurize it. As an example, in this embodiment, the pressure adjusting unit 13 is a piston 14 that moves back and forth within the chamber 11. By moving the piston 14 back and forth using a driving source (not shown), the volume of the first region V1 changes, and the pressure of the mixed gas in the first region V1 is adjusted. In other words, by making the pressure of the mixed gas in the first region V1 higher than the pressure in the second region V2, the mixed gas is forced into the separation unit 12, and then permeates the separation unit 12 for each chemical species.

[0016] FIG. 8 shows, as an example, the relationship between the pressure difference and the permeation rate when tritium (T), deuterium (D), and hydrogen (H) are permeated through palladium. As shown in the figure, under the same pressure difference, hydrogen has the highest permeation rate, followed by deuterium. Tritium has the lowest permeation rate. Therefore, when pressure is applied to the mixed gas, hydrogen permeates first to the second region V2 side, followed by tritium (and deuterium). In this way, the chemical species separation device 1 according to this embodiment is capable of separating these chemical species based on the difference in permeation rate of each chemical species through the metal material.

[0017] The thickness dimension of the separation section 12 (i.e., the dimension in the direction from the first region V1 to the second region V2) is set by the product of the speed at which hydrogen permeates the above-mentioned metal material and a predetermined control time (e.g., 3600 seconds). In other words, the thickness dimension of the metal material is determined so that almost all hydrogen will have permeated the separation section 12 when the control time has elapsed.

[0018] The chamber 11 of the device main body 10 and the separation section 12 can be removed as a unit from the gas flow path 20. Although not shown in detail, the chamber 11 is connected by various valves and seals so that it can be attached and detached from the gas flow path 20 while maintaining airtightness.

[0019] (Chemical species separation method) Next, a chemical species separation method using the above-mentioned chemical species separation device 1 will be described with reference to Figures 3 to 7. Note that the black circles in Figures 4 to 7 represent tritium, and the white circles represent hydrogen.

[0020] As shown in Figures 3 and 4, first, in step S1, the mixed gas is supplied to the first region V1 of the chamber 11. Next, in step S2, the pressure adjustment unit 13 is operated to pressurize the mixed gas. At this time, the permeation of the above chemical species progresses based on the pressure difference between the first region V1 and the second region V2 (Figures 5 and 6). Protium permeates the separation unit 12 before tritium and is stored in the second region V2.

[0021] When the above-mentioned management time has elapsed, step S3 is executed. In step S3, the light hydrogen in the second region V2 is recovered in the gas recovery section via the recovery passage 23. In this state, as shown in FIG. 6, the entire amount of tritium contained in the mixed gas is absorbed and captured in the separation section 12. In this state, the chamber 11 and the separation section 12 are removed from the gas passage 20 (step S4). Thereafter, the tritium is recovered from the separation section 12 by a separately provided recovery device 50.

[0022] 7, the recovery device 50 has a recovery pressure adjustment unit 51 having a piston 14 similar to the pressure adjustment unit 13, and a temperature adjustment unit 52 that adjusts the temperature of the separation unit 12. The chamber 11 in which the tritium is trapped and the separation unit 12 are loaded into this recovery device 50. The first region V1 side is pressurized by the piston 14, or the second region V2 side is put under negative pressure, while the temperature adjustment unit 52 is used to raise the temperature of the separation unit 12, thereby allowing tritium to permeate and be recovered from the separation unit 12 (step S5).

[0023] The collected tritium is stored in a container (not shown) or the like. After tritium has been collected, the separation unit 12 and the chamber 11 are again connected to the original gas flow path 20 (step S6). Steps S1 to S6 are repeated in order for the multiple chambers 11 and separation units 12. With the above, all steps of the chemical species separation method according to this embodiment are completed.

[0024] (Action and effect) Although a technique for absorbing tritium using an alloy film has been known, there has been no sufficient study on a method for treating the alloy film after absorbing tritium. In addition, since an alloy film generally contains expensive metal species, a cheaper and more efficient method and device for separating tritium has been desired from the viewpoint of reducing the operating and maintenance costs of the device.

[0025] According to the above configuration, the separation section 12 has a metal material that is permeable to tritium and hydrogen. When a mixed gas is supplied to the separation section 12 from the first region V1 side, and the pressure of the first region V1 is made higher than that of the second region V2 by the pressure adjustment section 13, hydrogen permeates first to the second region V2 side based on the difference in permeation rate. By continuing this pressurization process for a predetermined time, most of the hydrogen in the first region V1 permeates to the second region V2, and tritium, which has a low permeation rate, is captured in the metal material of the separation section 12. In this state, the chamber 11 and the separation section 12 can be removed from the gas flow path 20, and tritium can be recovered by a separately provided device. Thereafter, the chamber 11 and the separation section 12 from which tritium has been removed can be reused. This allows the separation section 12 formed of an expensive metal material to be used repeatedly to the maximum extent possible for a long period of time. Therefore, the maintenance cost and manufacturing cost of the device can be significantly reduced.

[0026] According to the above-mentioned configuration, the thickness of the separation section 12 is set by multiplying the speed at which hydrogen permeates the metal material by a predetermined control time. Therefore, the completion of hydrogen permeation can be known only by using this control time as an index. As a result, the number of parameters to be controlled is reduced, and the device can be operated more easily and efficiently.

[0027] According to the above configuration, the pressure of the first region V1 is increased by the pressure adjusting unit 13 while the temperature of the separation unit 12 is increased by the temperature adjusting unit 52, thereby making it possible to increase the permeation rate of tritium in the separation unit 12. This makes it possible to efficiently recover tritium from the separation unit 12 in a shorter time.

[0028] According to the above configuration, the metal material is an alloy containing at least one chemical species selected from the group including palladium, vanadium, niobium, tantalum, and nickel. This allows the use of an appropriate metal material that is permeable to tritium and hydrogen. Also, based on the difference in permeation rate, an optimal material that is suitable for the above management time can be selected.

[0029] According to the above method, after separation of hydrogen and tritium by the separation unit 12 is completed, the chamber 11 and separation unit 12 can be removed from the gas flow path 20 and replaced with another separation unit 12 and chamber 11. Tritium is recovered from the removed chamber 11 and separation unit 12. By repeatedly executing this step for a plurality of chambers 11 and separation units 12 in sequence, it is possible to process the mixed gas (i.e., separate hydrogen and tritium) in an apparently continuous manner. This makes it possible to achieve both a reduction in work time and a significant reduction in operating costs.

[0030] According to the above method, tritium absorbed in the separation section 12 can be simply and efficiently recovered based only on the pressure difference between the first region V1 and the second region V2. In particular, as long as a pressure adjusting device is prepared, hydrogen permeation and recovery and tritium permeation and recovery can be achieved in an apparatus of the same configuration, which makes it possible to further reduce the manufacturing and maintenance costs of the apparatus.

[0031] According to the above method, when recovering tritium, the separation section 12 is heated while increasing the pressure in the first region V1, thereby making it possible to increase the permeation rate of tritium in the separation section 12. This makes it possible to efficiently recover tritium from the separation section 12 in a shorter time.

[0032] (Other embodiments) Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of the present disclosure are also included.

[0033] For example, the number of the device main body 10 described in the above embodiment is an example, and can be changed as appropriate according to the design and specifications. Regardless of the number, the same action and effect as described above can be obtained. In particular, even if there is only one device main body 10, smooth operation is possible and the same action and effect as described above can be obtained. However, a configuration in which two or more device main bodies 10 are provided is more advantageous from the viewpoint of the possibility of continuous processing of the mixed gas.

[0034] Furthermore, in step S5 of recovering tritium, the gas on the second region V2 side may be sucked to promote desorption of tritium from the separation section 12. Even in this case, the same effects as those described above can be obtained.

[0035] Furthermore, the pressure adjusting unit 13 and the recovery pressure adjusting unit 51 do not necessarily have to have the above-mentioned piston 14, and may be configured to increase the pressure in the first space V1 higher than the pressure in the second space V2 only by the supply pressure of the mixed gas itself. Even in this case, in addition to obtaining the same effects as those described above, the configuration of the device is simplified, making it possible to significantly reduce manufacturing costs and maintenance costs.

[0036] In addition, the gas to be separated is not limited to hydrogen and tritium, and may further contain deuterium. In this case, the permeation rates through the separation unit 12 are high for hydrogen, low for deuterium, and low for tritium in that order. Based on the difference in permeation rate, each chemical species can be separated by the same configuration and method as described above.

[0037] Furthermore, the chemical species to be separated are not limited to hydrogen, tritium, and the like, and the above-described device and method can be applied to any mixed gas containing a plurality of isotopes having different permeation rates.

[0038] Moreover, the recovery device 50 used in step S5 for recovering tritium may have a configuration that does not include the temperature adjustment unit 52. However, raising the temperature of the separation unit 12 by the temperature adjustment unit 52 is advantageous in that the time required for recovery can be shortened.

[0039] <Additional Notes> The chemical species separating device 1 and the chemical species separating method described in each embodiment can be understood, for example, as follows.

[0040] (1) A chemical species separation device 1 according to a first embodiment is a chemical species separation device 1 that separates a mixed gas containing tritium and hydrogen into chemical species, and includes a chamber 11 having a space formed therein, a separation section 12 formed of a metal material through which the tritium and the hydrogen can permeate at different speeds and that divides the space within the chamber 11 into a first region V1 and a second region V2, a gas flow path 20 having a supply section that supplies the mixed gas to the first region V1 and an exhaust section that leads the separated chemical species from the second region V2 to the outside, and a pressure adjustment section 13 that adjusts the pressure in the first region V1 to be higher than the pressure in the second region V2, and each of the chambers 11 and the separation section 12 is detachable from the gas flow path 20.

[0041] According to the above configuration, the separation section 12 has a metal material that is permeable to tritium and hydrogen. When a mixed gas is supplied to the separation section 12 from the first region V1 side, and the pressure of the first region V1 is made higher than that of the second region V2 by the pressure adjustment section 13, hydrogen permeates first to the second region V2 side based on the difference in permeation rate. By continuing this pressurization treatment for a predetermined time, most of the hydrogen in the first region V1 permeates to the second region V2, and tritium, which has a low permeation rate, is captured in the metal material of the separation section 12. In this state, the chamber 11 and the separation section 12 can be removed from the gas flow path 20, and tritium can be recovered by a separately provided device. Thereafter, the chamber 11 and the separation section 12 from which tritium has been removed can be reused.

[0042] (2) The chemical species separation device 1 of the second aspect is the chemical species separation device 1 of (1), wherein the thickness of the separation section 12 in the direction from the first region V1 to the second region V2 is set based on the product of the rate at which the proton passes through the metal material and a predetermined control time.

[0043] According to the above-mentioned configuration, the thickness of the separation section 12 is set by multiplying the speed at which hydrogen permeates the metal material by a predetermined control time. Therefore, the completion of hydrogen permeation can be known only by using this control time as an index.

[0044] (3) The chemical species separation device 1 according to a third embodiment is the chemical species separation device 1 according to (1) or (2), further comprising a temperature adjustment unit 52 capable of raising the temperature of the separation unit 12.

[0045] According to the above configuration, by increasing the pressure in the first region V1 by the pressure adjusting unit 13 while raising the temperature of the separation unit 12 by the temperature adjusting unit 52, the permeation rate of tritium in the separation unit 12 can be increased.

[0046] (4) A chemical species separation device 1 according to a fourth aspect is a chemical species separation device 1 according to any one of the aspects (1) to (3), wherein the metal material is an alloy containing at least one chemical species selected from the group including palladium, vanadium, niobium, tantalum, and nickel.

[0047] According to the above configuration, the metal material is an alloy containing at least one chemical species selected from the group including palladium, vanadium, niobium, tantalum, and nickel, and thus a metal material that is permeable to tritium and hydrogen can be appropriately selected and used.

[0048] (5) A chemical species separation method according to a second aspect is a chemical species separation method using the chemical species separation device 1 according to any one of the aspects (1) to (4), and includes the steps of: supplying the mixed gas to the first region V1 by the supply unit; increasing the pressure of the first region V1 by the pressure adjustment unit 13; recovering the light hydrogen that has permeated the separation unit 12 by increasing the pressure from the second region V2; removing the chamber 11 and the separation unit 12 from the gas flow path 20 when adsorption of the tritium by the separation unit 12 is completed; recovering the tritium from the removed separation unit 12; and reinstalling the other chamber 11 and the separation unit 12 in the gas flow path 20 after the tritium has been recovered, for a plurality of the chambers 11 and a plurality of the separation units 12.

[0049] According to the above method, after separation of hydrogen and tritium by the separation unit 12 is completed, the chamber 11 and separation unit 12 can be removed from the gas flow path 20 and replaced with another separation unit 12 and chamber 11. Tritium is recovered from the removed chamber 11 and separation unit 12. By repeatedly executing this step for a plurality of chambers 11 and separation units 12 in sequence, it is possible to process the mixed gas (i.e., separate hydrogen and tritium) in an apparently continuous manner. This makes it possible to achieve both a reduction in work time and a significant reduction in operating costs.

[0050] (6) A chemical species separation device 1 according to a sixth aspect is a chemical species separation method according to (5), wherein in the step of recovering tritium, the tritium is discharged from the separation section 12 based on a pressure difference between the first region V1 and the second region V2.

[0051] According to the above method, tritium absorbed in the separation section 12 can be simply and efficiently recovered based only on the pressure difference between the first region V1 and the second region V2. In particular, as long as a pressure adjusting device is prepared, hydrogen permeation and recovery and tritium permeation and recovery can be achieved in an apparatus of the same configuration, which makes it possible to further reduce the manufacturing and maintenance costs of the apparatus.

[0052] (7) A chemical species separation apparatus 1 according to a seventh aspect is the chemical species separation method according to (6), in which the separation section 12 is heated in the step of recovering tritium.

[0053] According to the above method, when recovering tritium, the permeation rate of tritium in the separation section 12 can be increased by heating the separation section 12 while increasing the pressure in the first region V1. [Explanation of symbols]

[0054] 1... Chemical species separation device 10... Device body 11... Chamber 12... Separation section 13... Pressure adjustment section 14... Piston 20... Gas flow path 21... Supply flow path 22... Branch flow path 23... Recovery flow path 30... Gas supply source 40... Light hydrogen recovery section 50... Recovery device 51... Recovery pressure adjustment section 52... Temperature adjustment section V1... First region V2... Second region

Claims

1. A chemical species separation device that separates a mixed gas containing tritium and hydrogen into chemical species, A chamber having a space formed therein; a separation section formed of a metal material through which the tritium and the hydrogen can permeate at different speeds, and dividing a space within the chamber into a first region and a second region; a gas flow path including a supply portion for supplying the mixed gas to the first region and a discharge portion for leading the separated chemical species from the second region to the outside; a pressure adjusting unit that adjusts the pressure in the first region to be higher than the pressure in the second region; Equipped with The chemical species separation device, wherein the chamber and the separation unit are detachable from the gas flow path.

2. 2. The chemical species separation device according to claim 1, wherein a thickness of the separation portion in a direction from the first region toward the second region is set based on a product of a rate at which the protons permeate the metal material and a predetermined control time.

3. The chemical species separation apparatus according to claim 1 , further comprising a temperature adjustment unit capable of increasing the temperature of the separation unit.

4. 3. The chemical species separation device according to claim 1, wherein the metallic material is an alloy containing at least one chemical species selected from the group consisting of palladium, vanadium, niobium, tantalum, and nickel.

5. A method for separating chemical species using the chemical species separation device according to claim 1 or 2, supplying the mixed gas to the first region by the supply unit; Increasing the pressure in the first region by the pressure adjusting unit; recovering the hydrogen that has permeated the separation section from the second region due to the increased pressure; removing the chamber and the separation unit from the gas flow path when the adsorption of the tritium by the separation unit is completed; recovering the tritium from the removed separation portion; reinstalling the other chamber and the separation unit in the gas flow path after the tritium has been recovered; The chemical species separation method includes sequentially performing the above for a plurality of the chambers and a plurality of the separation units.

6. 6. The chemical species separation method according to claim 5, wherein in the step of recovering tritium, the tritium is discharged from the separation section based on a pressure difference between the first region and the second region.

7. The chemical species separation method according to claim 6 , wherein the step of recovering tritium comprises heating the separation section.

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