Hydrogen isotope separation system

Abstract

This invention provides a hydrogen isotope separation system that can suppress increases in power consumption. [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 heavy water containing light water toward the anode 15b, and a cathode supply path 10b that supplies an inert gas toward the cathode 15c. The hydrogen isotope separation system 10 includes a heat transfer medium circuit 30 that supplies a heat transfer medium to an anode-side humidifier 14A located in the anode supply path 10a, a cathode-side humidifier 14B located in the cathode supply path 10b, and the separator 15. The heat transfer medium circuit 30 heats the anode-side humidifier 14A with the heat transfer medium after heating the cathode-side humidifier 14B.

Description

Technical Field

[0001] The present invention relates to a hydrogen isotope separation system.

Background Art

[0002] In recent years, research and development have been conducted on fuel cells that contribute to energy efficiency in order to enable more people to access affordable, reliable, sustainable, and advanced energy. Conventionally, for example, a system is known in which raw water containing heavy water and tritium components is decomposed by an electrolytic cell having an ion exchange membrane and a catalyst to obtain hydrogen and oxygen each having a low content of deuterium and tritium (see, for example, Patent Document 1). In this system, by supplying hydrogen and oxygen obtained by the electrolytic cell to a fuel cell, water (light water) having a low content of heavy water and tritium components is extracted.

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 an increase in power consumption required for humidification. For example, in the case of a system using an ion exchange membrane for separation of hydrogen isotopes as in the above prior art, different humidification amounts and heat amounts are required in the humidifiers on the anode side and the cathode side, respectively. In this case, if independent control is performed according to the heat amount required in each humidifier, there is a risk of an increase in power consumption, and suppressing an increase in power consumption is an issue.

[0005] The present application aims to achieve suppression of an increase in power consumption in order to solve the above problems. And, by extension, it contributes to energy efficiency. [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 heavy water containing light water toward the anode, and a cathode supply path (for example, the cathode supply path in the embodiment) for supplying inert gas toward the cathode. 10b) comprises an anode-side humidifier (for example, an anode-side humidifier 14A in the embodiment) provided in the anode supply path, a cathode-side humidifier (for example, a cathode-side humidifier 14B in the embodiment) provided in the cathode supply path, and a heat transfer medium circuit (for example, a heat transfer medium circuit 30 in the embodiment) that supplies a heat transfer medium to the separator, the anode-side humidifier, and the cathode-side humidifier, wherein the heat transfer medium circuit includes a heater (for example, a heater 31 in the embodiment) that heats the heat transfer medium, and after supplying the heat transfer medium heated by the heater to the cathode-side humidifier, it supplies the heat transfer medium discharged from the cathode-side humidifier to the anode-side humidifier.

[0007] (2) In the hydrogen isotope separation system described in (1) above, the heat transfer medium circuit may supply the heat transfer medium heated by the heater to the separator, and then supply the heat transfer medium discharged from the separator to the cathode-side humidifier.

[0008] (3) In the hydrogen isotope separation system described in (1) or (2) above, the heat transfer medium circuit may connect the separator, the cathode-side humidifier, and the anode-side humidifier in series in sequence.

[0009] (4) In the hydrogen isotope separation system described in (3) above, the heat transfer medium circuit may supply the heat transfer medium discharged from the anode humidifier to the heater. [Effects of the Invention]

[0010] According to (1) above, by circulating the heat transfer medium in order of relatively large humidification amount (load), the system can be equipped with a heat transfer medium circuit that sequentially heats (increases the temperature) the cathode-side humidifier and the anode-side humidifier, thereby improving the heating efficiency of the system.

[0011] In the case of (2) above, the warming up of the separator, which has a relatively higher operating temperature, can be prioritized over the heating of the cathode-side humidifier. This suppresses the dew point of the humidified inert gas supplied from the cathode-side humidifier to the cathode of the separator from becoming higher than the temperature of the separator, thereby suppressing a decrease in separation efficiency due to condensation occurring inside the separator, for example.

[0012] In the case of (3) above, by connecting the separator, the cathode-side humidifier, and the anode-side humidifier sequentially in series, it is possible to suppress the complexity and size of the heat transfer medium circuit configuration.

[0013] In the case of (4) above, by circulating the heat transfer medium heated by the heater in order of the amount of heat required, it is possible to suppress an increase in the power consumption of the heater. [Brief explanation of the drawing]

[0014] [Figure 1] A diagram illustrating the configuration of a hydrogen isotope separation system according to an embodiment of the present invention. [Figure 2] A figure showing an example of an isotope exchange equilibrium reaction in the separator of a hydrogen isotope separation system according to an embodiment of the present invention. [Figure 3] A diagram illustrating the configuration of a heat transfer medium circuit in a hydrogen isotope separation system according to an embodiment of the present invention. [Modes for carrying out the invention]

[0015] Hereinafter, a 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 a hydrogen isotope separation system 10 according to the embodiment. As shown in FIG. 1, the hydrogen isotope separation system 10 according to the embodiment includes, for example, an anode supply path 10a and a cathode supply path 10b, an anode discharge path 10c and a cathode discharge path 10d, a heavy water tank 11, an electrolyzer 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, and an anode side tank 18A and a cathode side tank 18B.

[0016] The heavy water tank 11 stores, for example, water containing heavy water and light water. The heavy water tank 11 is connected to the anode supply path 10a. The heavy water tank 11 supplies water containing heavy water and light water to the electrolyzer 12 via the anode supply path 10a. Note that light water is ([ , , , ,

[0019] , H2 16 O), and heavy water is water containing at least one of hydrogen isotopes such as deuterium (D) and tritium (T). <00S0082>

[0017] The electrolyzer 12 includes, for example, an electrolytic cell or an electrolytic cell that electrolyzes water containing heavy water supplied from the heavy water tank 11. For example, the electrolyzer 12 is an electrolytic cell. The electrolyzer 12 is connected to the anode supply path 10a. In the electrolyzer 12, for example, an electrolytic reaction shown in the following formula (1) occurs. The electrolytic reaction in the electrolyzer 12 includes an electrolytic reaction obtained by replacing deuterium (D) in semi-heavy water (HDO) of the following formula (1) with tritium (T).

[0018]

Equation

[0019] For example, the electrolyzer 12 discharges hydrogen (H2), deuterium (D2), hydrogen deuteride (HD), tritium hydride (HT), etc. obtained by the electrolytic reaction into the anode supply path 10a. The electrolyzer 12 discharges oxygen (O2) obtained by the electrolytic reaction to the outside other than the anode supply path 10a. For example, the electrolyzer 12 may supply oxygen (O2) obtained by the electrolytic reaction to a coupler (not shown) such as an external fuel cell. For example, the coupler (not shown) may generate water (H2O) by recombining hydrogen (H2) supplied from a separator 15 described later and oxygen (O2) supplied from the electrolyzer 12 through a catalytic reaction.

[0020] The nitrogen tank 13 stores a gas such as air containing nitrogen (N2), for example. The nitrogen tank 13 is connected to the cathode supply path 10b. The nitrogen tank 13 supplies a gas such as air containing nitrogen (N2) to the cathode supply path 10b.

[0021] The anode-side humidifier 14A is provided between the electrolyzer 12 and the separator 15 in the anode supply path 10a. The anode-side humidifier 14A humidifies hydrogen (H2), deuterium (D2), hydrogen deuteride (HD), tritium hydride (HT), etc. supplied from the electrolyzer 12 with water such as water vapor and liquid. The cathode-side humidifier 14B is provided in the cathode supply path 10b. The cathode-side humidifier 14B humidifies a gas such as air containing nitrogen (N2) supplied from the nitrogen tank 13 with water such as water vapor and liquid.

[0022] The separator 15 includes, for example, a catalyst that separates hydrogen isotopes by an isotope exchange reaction from hydrogen (H2), deuterium (D2), hydrogen deuteride (HD), tritium hydride (HT), etc. supplied from the electrolyzer 12, or a fuel cell or the like. For example, the separator 15 is a fuel cell stack including cells of a plurality of stacked fuel cells. The cell of the fuel cell includes, for example, an ion exchange membrane (electrolyte membrane) 15a, an anode 15b and a cathode 15c provided on both sides in the thickness direction of the ion exchange membrane 15a, and an anode-side flow path 15d and a cathode-side flow path 15e.

[0023] 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.

[0024] 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 (D2), hydrogen deuteride (HD), and tritiated hydrogen (HT), for example, humidified with water such as water vapor and liquid, is supplied to the anode-side channel 15d from the anode-side humidifier 14A.

[0025] 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.

[0026] Figure 2 shows an example of an isotope exchange equilibrium 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 (2) below occurs at anode 15b, and the exchange reaction shown in 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 (2) and (3) below. Also, (g) in equations (2) and (3) below indicates the state of gas and vapor, etc.

[0027]

number

[0028]

number

[0029] 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).

[0030] 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.

[0031] 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.

[0032] Figure 3 is a diagram showing the configuration of the heat transfer medium circuit 30 in the hydrogen isotope separation system 10 of the embodiment. As shown in Figures 1 and 3, the hydrogen isotope separation system 10 includes, for example, a heat transfer medium circuit 30 connected to heat transfer medium channels (not shown) provided in the anode-side humidifier 14A and cathode-side humidifier 14B and the separator 15. The heat transfer medium circuit 30 includes, for example, a heater 31 that heats the heat transfer medium. The heat transfer medium circuit 30 forms a circulation circuit that circulates the heat transfer medium heated by the heater 31.

[0033] The heat medium circuit 30 is connected in series with, for example, a heater 31, a separator 15, a cathode-side humidifier 14B, and an anode-side humidifier 14A in this order from the upstream side to the downstream side along the flow direction of the heat medium. The heat medium at the first temperature T1 heated by the heater 31 is first supplied to the separator 15, thereby heating the separator 15 to a predetermined operating temperature. Next, the heat medium at the second temperature T2 (<T1) after heating the separator 15 is supplied to the cathode-side humidifier 14B, thereby heating the cathode-side humidifier 14B. Next, the heat medium at the third temperature T3 (<T2) after heating the cathode-side humidifier 14B is supplied to the anode-side humidifier 14A, thereby heating the anode-side humidifier 14A. Then, the heat medium at the fourth temperature T4 (<T3) after heating the anode-side humidifier 14A is returned to the heater 31.

[0034] For example, relatively, the humidification amount in the cathode-side heater 14B according to the supply flow rate F1 from the cathode supply path 10b is set to be larger than the humidification amount in the anode-side humidifier 14A according to the supply flow rate F2 (<F1) from the anode supply path 10a. Thereby, the amount of heat required in the cathode-side heater 14B is larger than the amount of heat required in the anode-side humidifier 14A. Relatively, the temperature change ΔT1 (=T2 - T3) of the heat medium in the cathode-side humidifier 14B is larger (ΔT1>ΔT2) than the temperature change ΔT2 (=T3 - T4) of the heat medium in the anode-side humidifier 14A.

[0035] As described above, according to the hydrogen isotope separation system 10 of the embodiment, by flowing the heat medium in order of relatively larger humidification amount (load), the heat medium circuit 30 that sequentially heats (raises the temperature) the cathode-side humidifier 14B and the anode-side humidifier 14A is provided, thereby improving the temperature rise efficiency in the system. In the heat transfer medium circuit 30, the heat transfer medium flows from the separator 15 to the cathode-side humidifier 14B, allowing the warming of the separator 15, which has a relatively higher operating temperature, to be prioritized over the temperature rise of the cathode-side humidifier 14B. This suppresses the dew point of the humidified inert gas supplied from the cathode-side humidifier 14B to the cathode 15c of the separator 15 from becoming higher than the temperature of the separator 15, thereby suppressing a decrease in separation efficiency due to condensation occurring inside the separator 15, for example.

[0036] By connecting the separator 15, the cathode-side humidifier 14B, and the anode-side humidifier 14A sequentially in series, it is possible to suppress the complexity and size of the heat transfer medium circuit 30. By circulating the heat transfer medium heated by the heater 31 in order of the amount of heat required, it is possible to suppress an increase in the power consumption of the heater 31.

[0037] (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 embodiment described above, the heat transfer medium circuit 30 is provided with a heater 31 for heating the heat transfer medium, but it is not limited to this, and instead of a heater 31 dedicated to heating, the heat transfer medium may be heated by a coupling device such as an external fuel cell as described above.

[0038] 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]

[0039] 10…Hydrogen isotope separation system, 10a…Anode supply path, 10b…Cathode supply path, 10c…Anode discharge path, 10d…Cathode discharge path, 11…Heavy water 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, 16B…Cathode-side condenser, 17A…Anode-side on / off valve, 17B…Cathode-side on / off valve, 18A…Anode-side tank, 18B…Cathode-side tank, 30…Heat transfer medium circuit, 31…Heater

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 heavy water containing light water toward the anode, A cathode supply path for supplying inert gas toward the cathode, an anode-side humidifier provided in the anode supply path, A cathode-side humidifier is provided in the cathode supply path, A heat transfer medium circuit that supplies heat transfer medium to the separator, the anode-side humidifier, and the cathode-side humidifier. Equipped with, The aforementioned heat transfer circuit is The system includes a heater for heating the heat transfer medium, After supplying the heat transfer medium heated by the heater to the cathode-side humidifier, the heat transfer medium discharged from the cathode-side humidifier is supplied to the anode-side humidifier. Hydrogen isotope separation system.

2. The aforementioned heat transfer circuit is After supplying the heat transfer medium heated by the heater to the separator, the heat transfer medium discharged from the separator is supplied to the cathode-side humidifier. The hydrogen isotope separation system according to claim 1.

3. The aforementioned heat transfer circuit is The separator, the cathode-side humidifier, and the anode-side humidifier are connected in series in sequence. A hydrogen isotope separation system according to claim 1 or claim 2.

4. The aforementioned heat transfer circuit is The heat transfer medium discharged from the anode-side humidifier is supplied to the heater. The hydrogen isotope separation system according to claim 3.

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