Hydrogen isotope separation system and control method for the hydrogen isotope separation system

Abstract

This invention provides a hydrogen isotope separation system that can suppress the decline in performance during shutdown. [Solution] The hydrogen isotope separation system 10 includes a separator 15 having an ion exchange membrane 15a, an anode 15b, and a cathode 15c. The hydrogen isotope separation system 10 includes an anode supply path 10a that supplies light hydrogen containing at least one type of hydrogen isotope toward the anode 15b, and a cathode supply path 10b that supplies cathode gas toward the cathode 15c. The hydrogen isotope separation system 10 includes an electrolytic unit 12 provided in the anode supply path 10a, condensers 16A and 16B provided on the discharge side of the separator 15, a second heat transfer medium circuit 40 that supplies a refrigerant to each condenser 16A and 16B, and a control device 50. The control device 50 stops the cooling of each condenser 16A and 16B by the second heat transfer medium circuit 40 after the electrolytic unit 12 and separator 15 are stopped during the system shutdown process.

Description

Technical Field

[0001] The present invention relates to a hydrogen isotope separation system and a method for controlling the hydrogen isotope separation system.

Background Art

[0002] In recent years, in order to enable more people to access affordable, reliable, sustainable, and advanced energy, research and development have been conducted on fuel cells that contribute to energy efficiency. Conventionally, for example, a system is known in which raw water containing heavy water and tritium components is decomposed by a water electrolysis cell to obtain hydrogen and oxygen each having a low content of deuterium and tritium (see, for example, Patent Document 1). This system dehumidifies and humidifies each of the hydrogen and oxygen obtained by the water electrolysis cell and supplies them to a fuel cell, and extracts water (light water) having a low content of heavy water and tritium components by dehumidifying the gas discharged from the fuel cell.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the technology related to fuel cells, it is an issue to suppress a decrease in the performance of the entire system when the system stops. For example, in the case of a system that uses a fuel cell for hydrogen isotope separation as in the above conventional technology, if the operations of the fuel cell, humidifier, and condenser at the time of stop are not properly controlled, the performance of isotope separation may decrease.

[0005] The present application aims to achieve suppression of a decrease in performance at the time of stop in order to solve the above problems. And it contributes to energy efficiency by extension. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the above objectives, the present invention employs the following embodiments. (1): A hydrogen isotope separation system according to one aspect of the present invention (for example, the hydrogen isotope separation system 10 in the embodiment) includes an ion exchange membrane (for example, the ion exchange membrane 15a in the embodiment), an anode (for example, the anode 15b in the embodiment) and a cathode (for example, the cathode 15c in the embodiment) provided on both sides in the thickness direction of the ion exchange membrane, a separator (for example, the separator 15 in the embodiment) for separating hydrogen isotopes, an anode supply path (for example, the anode supply path 10a in the embodiment) for supplying light hydrogen containing at least one type of hydrogen isotope toward the anode, and a cathode supply path for supplying cathode gas toward the cathode. The system comprises a supply line (for example, a cathode supply line 10b in the embodiment), an electrolytic unit (for example, an electrolytic unit 12 in the embodiment) provided in the anode supply line for electrolyzing heavy water containing light water, condensing separators (for example, an anode-side condenser 16A and a cathode-side condenser 16B in the embodiment) provided on the discharge sides of the anode and cathode of the separator, a refrigerant circuit (for example, a second heat transfer medium circuit 40 in the embodiment) for supplying refrigerant to the condensing separators, and a control device (for example, a control device 50 in the embodiment), wherein the control device stops the cooling of the condensing separator by the refrigerant circuit after the electrolytic unit and the separator are stopped during the system shutdown process.

[0007] (2) The hydrogen isotope separation system described in (1) above includes an inert gas supply path (for example, an inert gas supply path 10e in the embodiment) that supplies a drying inert gas toward the anode and the cathode, and the control device may supply the drying inert gas to the separator via the inert gas supply path after the electrolytic unit has been stopped during the system shutdown process and while the refrigerant circuit is operating.

[0008] (3) The hydrogen isotope separation system described in (2) above includes a detector (for example, an impedance detector 20 in the embodiment) that detects a state quantity related to the wet state of the separator, and the control device may continue to supply the drying inert gas through the inert gas supply path when the drying inert gas is supplied through the inert gas supply path during the system shutdown process until the wet state corresponding to the state quantity detected by the detector reaches a predetermined wet state.

[0009] (4) The hydrogen isotope separation system described in (2) above includes a detector (for example, an impedance detector 20 in the embodiment) that detects a state quantity related to the wet state of the separator, and the control device may stop cooling the condensing separator by the refrigerant circuit when the wet state corresponding to the state quantity detected by the detector reaches a predetermined wet state when the drying inert gas is supplied by the inert gas supply path during the system shutdown process.

[0010] (5) In the hydrogen isotope separation system described in (3) or (4) above, the inert gas supply path may be provided with on-off valves (for example, a first on-off valve 22A and a second on-off valve 22B in the embodiment) between the anode supply path and the cathode supply path, and may be connected to the anode supply path and the cathode supply path, respectively, via the on-off valves.

[0011] (6) In the hydrogen isotope separation system described in (3) or (4) above, the detector may detect the impedance of the separator.

[0012] (7): A control method for a hydrogen isotope separation system according to one aspect of the present invention (for example, the hydrogen isotope separation system 10 in the embodiment) includes an ion exchange membrane (for example, the ion exchange membrane 15a in the embodiment), an anode (for example, the anode 15b in the embodiment) and a cathode (for example, the cathode 15c in the embodiment) provided on both sides in the thickness direction of the ion exchange membrane, and a separator (for example, the separator 15 in the embodiment) for separating hydrogen isotopes, and a separator containing at least one or more hydrogen isotopes toward the anode An anode supply path for supplying light hydrogen (for example, anode supply path 10a in the embodiment), a cathode supply path for supplying cathode gas toward the cathode (for example, cathode supply path 10b in the embodiment), an inert gas supply path for supplying drying inert gas toward the anode and the cathode (for example, inert gas supply path 10e in the embodiment), an electrolytic device provided in the anode supply path for electrolyzing heavy water containing light water (for example, electrolytic device 12 in the embodiment), and the anode and cathode of the separator A control method performed by an electronic device (e.g., a control device 50 in an embodiment) that controls a hydrogen isotope separation system comprising: condensers provided on the discharge side of each of the cathodes (e.g., an anode-side condenser 16A and a cathode-side condenser 16B in the embodiment); a refrigerant circuit (e.g., a second heat transfer medium circuit 40 in the embodiment) that supplies a refrigerant to the condensers; and a detector (e.g., an impedance detector 20 in the embodiment) that detects a state quantity related to the wet state of the separator, the control method includes: a first step (e.g., step S01 in the embodiment) of stopping the electrolytic device when a system shutdown process is performed; a second step (e.g., step S02 in the embodiment) of supplying the drying inert gas to the separator through the inert gas supply path after the execution of the first step; and a third step (e.g., step S05 in the embodiment) of stopping the cooling of the condensers by the refrigerant circuit when the wet state corresponding to the state quantity detected by the detector reaches a predetermined wet state after the execution of the second step. [Effects of the Invention]

[0013] According to (1) above, by providing a control device that stops the cooling of the condensing separator by the refrigerant circuit after the electrolytic and separator have stopped during the system shutdown process, the desired operation of the condensing separator can be continued until the electrolytic and separator have stopped. This makes it possible to suppress the increase in the concentration of deuterium and tritium on the discharge side of the condensing separator.

[0014] In the case of (2) above, by drying the inside of the separator with an inert drying gas while continuing the desired operation of the condensing separator, it is possible to suppress the deterioration of the separator while suppressing the increase in the concentration of deuterium and tritium on the discharge side of the condensing separator.

[0015] In the case of (3) above, the supply of drying inert gas is continued until the inside of the separator reaches a predetermined humid state, thereby effectively suppressing the deterioration of the separator.

[0016] In the case of (4) above, the cooling of the condenser separator is stopped when the inside of the separator reaches a predetermined humid state, thereby preventing the unnecessary continuation of cooling of the condenser separator.

[0017] In the case of (5) above, a portion of each of the anode supply path and cathode supply path can be used in combination for supplying drying inert gas. For example, compared to the case where a dedicated inert gas supply path is provided independently of the anode supply path and cathode supply path, the system can be made larger. When supplying drying inert gas, the operation of the separator can be stopped precisely, and the inside of the separator can be dried quickly.

[0018] In the case of (6) above, for example, the humidity state of the separator can be properly obtained without the need to provide a humidity sensor or the like.

[0019] According to (7) above, after the electrolyzer and the separator are stopped during the system stop process, the cooling of the condensation separator by the refrigerant circuit is stopped, so that the desired operation of the condensation separator can be continued until the electrolyzer and the separator stop. It is possible to suppress an increase in the concentrations of deuterium and tritium on the discharge side of the condensation separator. While drying the inside of the separator with a drying inert gas and continuing the desired operation of the condensation separator, it is possible to suppress an increase in the concentrations of deuterium and tritium on the discharge side of the condensation separator while suppressing deterioration of the separator. By continuing the supply of the drying inert gas until the inside of the separator reaches a predetermined wet state, deterioration of the separator can be accurately suppressed. When the inside of the separator reaches a predetermined wet state, the cooling of the condensation separator is stopped, so that it is possible to suppress unnecessary continuation of the cooling of the condensation separator.

Brief Description of the Drawings

[0020] [Figure 1] Configuration diagram of the hydrogen isotope separation system according to an embodiment of the present invention. [Figure 2] Diagram showing an example of an isotope exchange reaction in the separator of the hydrogen isotope separation system according to an embodiment of the present invention. [Figure 3] Flowchart showing the operation during the stop process of the hydrogen isotope separation system according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0021] Hereinafter, the hydrogen isotope separation system according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a configuration diagram of the hydrogen isotope separation system 10 according to the embodiment. As shown in Figure 1, the hydrogen isotope separation system 10 of the embodiment includes, for example, an anode supply channel 10a and a cathode supply channel 10b, an anode discharge channel 10c and a cathode discharge channel 10d, a raw material tank 11, an electrolytic unit 12, a nitrogen tank 13, an anode-side humidifier 14A and a cathode-side humidifier 14B, a separator 15, an anode-side condenser 16A and a cathode-side condenser 16B, an anode-side on-off valve 17A and a cathode-side on-off valve 17B, an anode-side tank 18A and a cathode-side tank 18B.

[0022] The raw material tank 11 stores water containing, for example, heavy water and light water. The raw material tank 11 is connected to the anode supply line 10a. The raw material tank 11 supplies water containing heavy water and light water to the electrolytic heater 12 via the anode supply line 10a. Note that light water is ( 1 H2 16 Heavy water is water containing at least one of the hydrogen isotopes, such as deuterium (D) and tritium (T).

[0023] The electrolytic apparatus 12 includes, for example, an electrolytic cell or electrolytic cell for electrolyzing water containing heavy water supplied from the raw material tank 11. For example, the electrolytic apparatus 12 is an electrolytic cell. The electrolytic apparatus 12 is connected to the anode supply path 10a. In electrolytic apparatus 12, for example, the electrolytic reaction shown in the following formula (Equation 1) occurs. The electrolytic reaction in electrolytic apparatus 12 includes the electrolytic reaction of heavy water (D2O) and semi-heavy water (HDO) as shown in the following formula (Equation 1).

[0024]

number

[0025] For example, the electrolytic unit 12 discharges hydrogen (H2), deuterium (D2), hydrogen deuteride (HD), and hydrogen tritiate (HT) obtained by the electrolytic reaction into the anode supply channel 10a. The electrolytic unit 12 discharges oxygen (O2) obtained by the electrolytic reaction to the outside other than the anode supply channel 10a. For example, the electrolytic unit 12 may supply the oxygen (O2) obtained by the electrolytic reaction to an external coupling device (not shown), such as a fuel cell. For example, the coupling device (not shown) may produce water (H2O) by recombining hydrogen (H2) supplied from the separator 15 (described later) and oxygen (O2) supplied from the electrolytic unit 12 in a catalytic reaction.

[0026] The nitrogen tank 13 stores gases such as air containing nitrogen (N2). The nitrogen tank 13 is connected to the cathode supply passage 10b. The nitrogen tank 13 supplies gases such as air containing nitrogen (N2) to the cathode supply passage 10b.

[0027] The anode-side humidifier 14A is installed between the electrolytic unit 12 and the separator 15 in the anode supply path 10a. The anode-side humidifier 14A humidifies the hydrogen (H2), deuterium (D2), hydrogen deuteride (HD), and hydrogen tritiate (HT), etc., supplied from the electrolytic unit 12 with water, such as water vapor and liquid water. The cathode-side humidifier 14B is installed in the cathode supply path 10b. The cathode-side humidifier 14B humidifies gases such as air containing nitrogen (N2) supplied from the nitrogen tank 13 with water vapor and liquid water, for example.

[0028] The separator 15 includes, for example, a catalyst or fuel cell that separates hydrogen isotopes from hydrogen (H2), deuterium (D2), hydrogen deuteride (HD), and hydrogen tritiate (HT) supplied from the electrolytic unit 12 by an isotope exchange reaction. For example, the separator 15 is a fuel cell stack comprising a plurality of stacked fuel cell cells. A fuel cell cell comprises, for example, an ion exchange membrane (electrolyte membrane) 15a, an anode 15b and a cathode 15c provided on both sides of the thickness direction of the ion exchange membrane 15a, and an anode-side flow path 15d and a cathode-side flow path 15e.

[0029] The ion exchange membrane 15a includes, for example, a proton exchange membrane or an anion exchange membrane. The anode 15b includes, for example, a platinum-based anode catalyst and a gas diffusion layer. The cathode 15c includes, for example, a platinum-based cathode catalyst and a gas diffusion layer.

[0030] The anode-side channel 15d is formed between the anode 15b and the separator 15, for example, by an anode-side separator. The anode-side channel 15d is connected to the anode-side humidifier 14A by an anode supply channel 10a outside the separator 15. Hydrogen (H2), deuterium (HD), and tritiated hydrogen (HT), humidified with water such as water vapor and liquid, are supplied to the anode-side channel 15d from the anode-side humidifier 14A.

[0031] The cathode-side channel 15e is formed between the cathode 15c and the cathode 15c by, for example, a cathode-side separator. The cathode-side channel 15e is connected to the cathode-side humidifier 14B by a cathode supply channel 10b outside the separator 15. A gas, such as air containing nitrogen (N2) humidified with water, such as water vapor and liquid water, is supplied to the cathode-side channel 15e from the cathode-side humidifier 14B.

[0032] Figure 2 shows an example of an isotope exchange reaction in the separator 15 of the hydrogen isotope separation system 10 of the embodiment. As shown in Figure 2, in the separator 15, isotope exchange reactions occur between water and hydrogen at the anode 15b and cathode 15c. Hydrogen isotopes such as deuterium (D) and tritium (T) move to the oxide side, and also move from the anode 15b side to the cathode 15c side through the ion exchange membrane 15a. For example, the exchange reaction shown in equation (Equation 2) below occurs at anode 15b, and the exchange reaction shown in equation (Equation 3) below occurs at cathode 15c. Note that the exchange reactions at anode 15b and cathode 15c include the exchange reactions obtained by replacing deuterium (D) with tritium (T) in hydrogen deuteride (HD) and semi-heavy water (HDO) in equations (Equation 2) and (Equation 3) below. Also, (g) in equations (Equation 2) and (Equation 3) below indicates the state of gas and vapor, etc.

[0033]

number

[0034]

number

[0035] In separator 15, for example, semi-heavy water (HDO), hydrogen deuteride (HD), tritiated water (HTO), and tritiated hydrogen (HT) move from the anode 15b side to the cathode 15c side via the ion exchange membrane 15a. In separator 15, for example, water (H2O) moves from the cathode 15c side to the anode 15b side via the ion exchange membrane 15a. At the anode 15b of the separator 15, for example, water (H2O), semi-heavy water (HDO), and tritiated water (HTO) are discharged to the external anode discharge channel 10c along with hydrogen (H2). At the cathode 15c of the separator 15, for example, water (H2O) carried by nitrogen (N2) gas is discharged to the external cathode discharge channel 10d along with semi-heavy water (HDO) and tritiated water (HTO).

[0036] As shown in Figure 1, the anode condenser 16A is provided in the anode discharge channel 10c. The cathode condenser 16B is provided in the cathode discharge channel 10d. The anode condenser 16A and the cathode condenser 16B each separate the fluid discharged from the anode channel 15d and the cathode channel 15e of the separator 15 into a gaseous component and a liquid component. The liquid component is, for example, light water and heavy water separated from the fluid by condensation.

[0037] For example, the gaseous component separated in the anode condenser 16A is hydrogen (H2), and the liquid components are light water (H2O) and heavy water (HDO, HTO). For example, the gaseous component separated by the anode condenser 16A is discharged to the outside via the anode valve 17A. The liquid components are discharged, for example, to the anode tank 18A. As mentioned above, the hydrogen (H2) discharged from the anode condenser 16A may be supplied to an external fuel cell or other coupling device (not shown) and used for power generation by catalytic reaction and water (H2O) production. For example, the gaseous component separated in the cathode-side condenser 16B is nitrogen (N2) or air, and the liquid components are light water (H2O) and heavy water (HDO, HTO). For example, the gaseous component separated by the cathode-side condenser 16B is discharged to the outside via the cathode-side on / off valve 17B. The liquid component is discharged, for example, to the cathode-side tank 18B.

[0038] The hydrogen isotope separation system 10 includes, for example, an impedance detector 20, an inert gas tank 21, an inert gas supply path 10e, and a first on-off valve 22A and a second on-off valve 22B. The impedance detector 20 is connected, for example, to the anode 15b and cathode 15c of the separator 15 to detect the impedance of the separator 15. The impedance of the separator 15 is a state variable related to the wet state or water content of the separator 15. For example, as the water content of the separator 15 increases, the impedance tends to decrease.

[0039] The inert gas tank 21 stores an inert gas, such as nitrogen (N2). The inert gas tank 21 is connected to the inert gas supply passage 10e. The inert gas tank 21 supplies a drying inert gas, such as nitrogen (N2), to the inert gas supply passage 10e. The inert gas supply path 10e forms a T-shaped flow path that branches from the inert gas tank 21 towards the anode supply path 10a and the cathode supply path 10b, respectively. The inert gas supply path 10e connects the inert gas tank 21 to the section between the anode-side humidifier 14A and the separator 15 in the anode supply path 10a and to the section between the cathode-side humidifier 14B and the separator 15 in the cathode supply path 10b.

[0040] The first on-off valve 22A is positioned, for example, between the inert gas tank 21 and the anode supply passage 10a in the inert gas supply passage 10e. The second on-off valve 22B is positioned, for example, between the inert gas tank 21 and the cathode supply passage 10b in the inert gas supply passage 10e. As will be described later, the first on-off valve 22A and the second on-off valve 22B are switched from closed (OFF) to open (ON) when, for example, unhumidified (i.e., dry) inert gas is supplied to the anode 15b and cathode 15c of the separator 15 during system shutdown processing.

[0041] The hydrogen isotope separation system 10 includes, for example, a first heat transfer medium circuit 30, a second heat transfer medium circuit 40, and a control device 50. The first heat transfer medium circuit 30 is connected, for example, to heat transfer medium flow paths (not shown) provided in the anode-side humidifier 14A and cathode-side humidifier 14B and the separator 15. The first heat transfer medium circuit 30 includes, for example, a heater 31 for heating the first heat transfer medium, a first temperature sensor 32, a second temperature sensor 33, and a third temperature sensor 34. The first heat transfer medium circuit 30 forms a circulation circuit for circulating the first heat transfer medium heated by the heater 31.

[0042] The first heat medium circuit 30 is connected in series, for example, in the flow direction of the first heat medium, sequentially from the upstream side to the downstream side, to a heater 31, a separator 15, a cathode-side humidifier 14B, and an anode-side humidifier 14A. The first heat medium heated by the heater 31 is first supplied to the separator 15 to heat the separator 15 to a predetermined operating temperature. Next, the first heat medium at the first temperature T1 after heating the separator 15 is supplied to the cathode-side humidifier 14B to heat the cathode-side humidifier 14B. The first temperature sensor 32 is disposed, for example, between the separator 15 and the cathode-side humidifier 14B to detect the first temperature T1 of the first heat medium.

[0043] Next, the first heat medium at the second temperature T2 (<T1) after heating the cathode-side humidifier 14B is supplied to the anode-side humidifier 14A to heat the anode-side humidifier 14A. The second temperature sensor 33 is disposed, for example, between the cathode-side humidifier 14B and the anode-side humidifier 14A to detect the second temperature T2 of the first heat medium. Then, the first heat medium at the third temperature T3 (<T2) after heating the anode-side humidifier 14A is returned to the heater 31. The third temperature sensor 34 is disposed, for example, between the anode-side humidifier 14A and the heater 31 to detect the third temperature T3 of the first heat medium.

[0044] The second heat medium circuit 40 is connected, for example, to heat medium flow paths (not shown) provided in each of the anode-side condenser 16A and the cathode-side condenser 16B. The second heat medium circuit 40 includes, for example, a cooler 41 that cools the second heat medium and a fourth temperature sensor 42. The second heat medium circuit 40 forms a circulation circuit that circulates the second heat medium cooled by the cooler 41.

[0045] The second heat medium circuit 40 is connected in series, for example, in the flow direction of the second heat medium, sequentially from the upstream side to the downstream side, to the cooler 41, the anode-side condenser 16A, and the cathode-side condenser 16B. The second heat transfer medium, cooled by the cooler 41, is first supplied to the anode condenser 16A, thereby cooling the anode condenser 16A. Next, the second heat transfer medium, after cooling the anode condenser 16A, is supplied to the cathode condenser 16B to cool the cathode condenser 16B. Then, the second heat transfer medium at a fourth temperature T4 after cooling the cathode-side condenser 16B is returned to the cooler 41. The fourth temperature sensor 42 is placed, for example, between the cathode-side condenser 16B and the cooler 41 to detect the fourth temperature T4 of the second heat transfer medium.

[0046] The control device 50 comprehensively controls the operation of the hydrogen isotope separation system 10, for example. For example, the control device 50 is a software function unit that functions when a predetermined program is executed by a processor such as a CPU (Central Processing Unit). The software function unit is an ECU (Electronic Control Unit) equipped with a processor such as a CPU, a ROM (Read Only Memory) for storing the program, a RAM (Random Access Memory) for temporarily storing data, and electronic circuits such as a timer. At least a part of the control device 50 may be an integrated circuit such as an LSI (Large Scale Integration).

[0047] (Operation of the hydrogen isotope separation system) The operation of the hydrogen isotope separation system 10 according to this embodiment will be described below. Figure 3 is a flowchart showing the operation of the hydrogen isotope separation system 10 of the embodiment during the shutdown process. As shown in Figure 3, first, the control device 50 stops the operation of the electrolytic unit 12 when the hydrogen isotope separation system 10 is shut down (step S01). This stops the supply of humidified gases (anode gases) such as hydrogen (H2), hydrogen deuteride (HD), and hydrogen tritiate (HT) from the electrolytic unit 12 to the anode 15b of the separator 15 via the anode-side humidifier 14A. Next, the control device 50 stops heating the separator 15, cathode-side humidifier 14B, and anode-side humidifier 14A by the first heat transfer medium circuit 30. The control device 50 stops supplying humidified gas (cathode gas), such as air containing nitrogen (N2), from the nitrogen tank 13 to the cathode 15c of the separator 15 via the cathode-side humidifier 14B (step S02).

[0048] Next, the control device 50 starts supplying inert gas from the inert gas tank 21 to the inert gas supply path 10e. The control device 50 switches the first on-off valve 22A and the second on-off valve 22B from closed (OFF) to open (ON) (step S03). As a result, unhumidified (i.e., dry) inert gas is supplied to the anode 15b and cathode 15c of the separator 15.

[0049] Next, the control device 50 determines, for example, whether the impedance of the separator 15 detected by the impedance detector 20 is greater than or equal to a predetermined value (step S04). The predetermined value of the impedance is, for example, the lower limit impedance corresponding to the upper limit moisture content required to bring the inside of the separator 15 to a desired dry state by drying with an inert gas. If the result of this determination is "NO", the control device 50 repeatedly performs the determination process in step S04. On the other hand, if the result of this determination is "YES", the control device 50 proceeds to step S05. Then, the control device 50 stops the cooling of the anode condenser 16A and the cathode condenser 16B by the second heat transfer fluid circuit 40 (step S05). As a result, the anode condenser 16A and the cathode condenser 16B stop operating.

[0050] Next, the control device 50 stops the supply of inert gas from the inert gas tank 21 to the inert gas supply passage 10e. The control device 50 switches the first on-off valve 22A and the second on-off valve 22B from open (ON) to closed (OFF) (step S06). Then, the control device 50 proceeds to the end of the process.

[0051] As described above, according to the hydrogen isotope separation system 10 and the control method for the hydrogen isotope separation system 10 of the embodiment, by providing a control device 50 that stops the cooling of each condenser 16A and 16B by the second heat transfer medium circuit 40 after the electrolytic heater 12 and separator 15 are stopped during the system shutdown process, the desired operation of each condenser 16A and 16B can be continued until the electrolytic heater 12 and separator 15 are stopped. It is possible to suppress the increase in the concentration of deuterium and tritium on the discharge side of each condenser 16A and 16B.

[0052] By drying the inside of the separator 15 with an inert gas for drying while continuing the desired operation of each condenser 16A and 16B, it is possible to suppress the deterioration of the separator 15 while suppressing the increase in the concentration of deuterium and tritium on the discharge side of each condenser 16A and 16B. By continuing to supply an inert gas for drying until the inside of the separator 15 reaches a predetermined humid state, the deterioration of the separator 15 can be effectively suppressed. When the inside of the separator 15 reaches a predetermined humid state, the cooling of each condenser 16A and 16B is stopped, thereby preventing the unnecessary continuation of cooling of each condenser 16A and 16B.

[0053] A portion of each of the anode supply path 10a and cathode supply path 10b can be used for supplying an inert gas for drying. For example, compared to having a dedicated inert gas supply path independent of the anode supply path 10a and cathode supply path 10b, the system can be made larger. When supplying the inert gas for drying, the operation of the separator 15 can be stopped precisely, and the inside of the separator 15 can be dried quickly. By providing the impedance detector 20, the humidity state of the separator 15 can be properly obtained without the need to provide, for example, a humidity sensor.

[0054] (modified version) Modified examples of the embodiments are described below. Note that parts identical to those in the embodiments described above are denoted by the same reference numerals, and their descriptions are omitted or simplified. In the embodiments described above, the hydrogen isotope separation system 10 is provided with an inert gas tank 21 connected to the inert gas supply path 10e, but is not limited thereto. For example, instead of the inert gas tank 21 and the inert gas supply path 10e connected to the inert gas tank 21, the hydrogen isotope separation system 10 may be provided with an inert gas supply path connected to a nitrogen tank 13. The inert gas supply path connected to the nitrogen tank 13 may bypass the cathode-side humidifier 14B and be connected to the anode supply path 10a and cathode supply path 10b via the first on-off valve 22A and the second on-off valve 22B.

[0055] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These embodiments can be carried out in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0056] 10…Hydrogen isotope separation system, 10a…Anode supply path, 10b…Cathode supply path, 10c…Anode discharge path, 10d…Cathode discharge path, 10e…Inert gas supply path, 11…Raw material tank, 12…Electrolyzer, 13…Nitrogen tank, 14A…Anode-side humidifier, 14B…Cathode-side humidifier, 15…Separator, 15a…Ion exchange membrane, 15b…Anode, 15c…Cathode, 16A…Anode-side condenser (condensation separator), 16B…Cathode-side condenser (condensation separator), 17 A... Anode-side shut-off valve, 17B... Cathode-side shut-off valve, 18A... Anode-side tank, 18B... Cathode-side tank, 20... Impedance detector (detector), 21... Inert gas tank, 22A... First shut-off valve (shut-off valve), 22B... Second shut-off valve (shut-off valve), 30... First heat transfer fluid circuit, 31... Heater, 32... First temperature sensor, 33... Second temperature sensor, 34... Third temperature sensor, 40... Second heat transfer fluid circuit (refrigerant circuit), 41... Cooler, 42... Fourth temperature sensor, 50... Control device.

Claims

1. A separator for separating hydrogen isotopes, comprising an ion exchange membrane and an anode and a cathode provided on both sides of the ion exchange membrane in the thickness direction, an anode supply path that supplies light hydrogen containing at least one type of hydrogen isotope toward the anode, A cathode supply path for supplying cathode gas toward the cathode, An electrolytic device is provided in the anode supply path for electrolyzing heavy water containing light water, A condensation separator provided on the discharge side of the anode and cathode of the separator, A refrigerant circuit that supplies refrigerant to the condenser separator, Control device and Equipped with, The control device is After the electrolytic converter and separator are shut down during the system shutdown process, the cooling of the condensing separator by the refrigerant circuit is stopped. Hydrogen isotope separation system.

2. The system includes an inert gas supply path that supplies a drying inert gas toward the anode and the cathode, The control device is After the electrolytic unit is shut down during the system shutdown process and while the refrigerant circuit is operating, the drying inert gas is supplied to the separator via the inert gas supply path. The hydrogen isotope separation system according to claim 1.

3. The separator is equipped with a detector that detects a state quantity related to the wet state, The control device is During the system shutdown process, when the drying inert gas is supplied through the inert gas supply path, the supply of the drying inert gas through the inert gas supply path is continued until the wet state, according to the state quantity detected by the detector, reaches a predetermined wet state. The hydrogen isotope separation system according to claim 2.

4. The separator is equipped with a detector that detects a state quantity related to the wet state, The control device is During the system shutdown process, when the drying inert gas is supplied through the inert gas supply path, if the wet state, according to the state quantity detected by the detector, reaches a predetermined wet state, the cooling of the condenser separator by the refrigerant circuit is stopped. The hydrogen isotope separation system according to claim 2.

5. The aforementioned inert gas supply path is The system includes an on-off valve provided between each of the anode supply path and the cathode supply path, and is connected to each of the anode supply path and the cathode supply path via the on-off valve. A hydrogen isotope separation system according to claim 3 or claim 4.

6. The detector detects the impedance of the separator. A hydrogen isotope separation system according to claim 3 or claim 4.

7. A separator for separating hydrogen isotopes, comprising an ion exchange membrane and an anode and a cathode provided on both sides of the ion exchange membrane in the thickness direction, an anode supply path that supplies light hydrogen containing at least one type of hydrogen isotope toward the anode, A cathode supply path for supplying cathode gas toward the cathode, An inert gas supply path for supplying drying inert gas toward the anode and the cathode, An electrolytic device is provided in the anode supply path for electrolyzing heavy water containing light water, A condensation separator provided on the discharge side of the anode and cathode of the separator, A refrigerant circuit that supplies refrigerant to the condenser separator, A detector for detecting a state quantity related to the wet state of the separator and A control method performed by an electronic device that controls a hydrogen isotope separation system comprising: The first step is to stop the electrolytic device during the system shutdown process, After the first step is performed, the second step is to supply the drying inert gas to the separator through the inert gas supply path, After the execution of the second step, if the wet state corresponding to the state quantity detected by the detector reaches a predetermined wet state, the third step is to stop the cooling of the condenser separator by the refrigerant circuit. including A method for controlling a hydrogen isotope separation system.

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