Regenerative fuel cell system

Abstract

To make a hydrogen-oxygen mixed gas in a fuel cell chamber harmless without discharging it into vacuum.SOLUTION: The regenerative fuel cell system is provided with a fuel cell unit, a fuel cell chamber for housing the fuel cell unit, a water tank for storing water discharged from the fuel cell unit, a toxic gas removing device into which gas from an arbitrary place is introduced through a gas introduction passage, and a water discharge passage for discharging water generated in the toxic gas removing device to the water tank.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This specification discloses techniques related to regenerative fuel cell systems. [Background technology]

[0002] Patent Document 1 discloses a regenerative fuel cell system. In this regenerative fuel cell system, the reactant gas generated in the fuel cell system is separated into oxygen gas and water or hydrogen gas and water using a gas-liquid separator, and the separated water is electrolyzed to obtain oxygen and hydrogen, which are then supplied back to the fuel cell system. This type of regenerative fuel cell system is suitable for use on the lunar surface and in cryogenic environments. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-015282 Summary of the Invention [Problem to be solved by the invention]

[0004] As mentioned above, the regenerative fuel cell system described in Patent Document 1 is suitable for use on the lunar surface and in cryogenic environments. When using a regenerative fuel cell system in such a harsh environment, a fuel cell chamber may be provided to house the fuel cell unit in order to protect it. When the fuel cell unit is housed in the fuel cell chamber, hydrogen and oxygen that permeate from the fuel cell unit may remain in the fuel cell chamber as a mixed gas. Therefore, a technology is needed to detoxify the gas in the fuel cell chamber. The purpose of this specification is to detoxify the hydrogen-oxygen mixed gas in the fuel cell chamber without releasing (discarding) it into a vacuum in a regenerative fuel cell system in which the fuel cell unit is housed in the fuel cell chamber. [Means for solving the problem]

[0005] In a first aspect disclosed in this specification, a regenerative fuel cell system may include a fuel cell unit, a fuel cell chamber housing the fuel cell unit, a water tank for storing water discharged from the fuel cell unit, a toxic gas removal device into which gas from any location is introduced through a gas introduction path, and a water discharge path for discharging water generated in the toxic gas removal device into the water tank.

[0006] In the above configuration, for example, by connecting the fuel cell chamber and the toxic gas removal device with a gas inlet passage, it is possible to prevent the permeated hydrogen gas generated from the fuel cell unit from accumulating in the fuel cell chamber as a mixed gas with oxygen. Alternatively, for example, by connecting the water tank and the toxic gas removal device with a gas inlet passage, it is possible to prevent the hydrogen and oxygen dissolved in the water supplied from the fuel cell unit to the water tank from volatilizing and becoming a hydrogen-oxygen mixed gas that accumulating in the water tank.

[0007] In a second aspect, in the first aspect, the gas generated in the fuel cell chamber may be introduced into the toxic gas removal device.

[0008] With the above configuration, hydrogen gas can be removed from the fuel cell chamber. Furthermore, the hydrogen gas that would otherwise remain in the fuel cell chamber can be used to generate water. The generated water can be electrolyzed and reused as a raw material for power generation in the fuel cell unit.

[0009] In a third aspect, in the first or second aspect, the gas generated in the water tank may be introduced into the toxic gas removal device.

[0010] According to the above configuration, hydrogen gas present in the water tank can be removed. Removing hydrogen gas from the water tank contributes to removing hydrogen gas dissolved in water, reducing the risk of hydrogen gas being mixed into the high-pressure oxygen storage gas after water electrolysis. In addition, it is possible to prevent hydrogen and oxygen from being desorbed from the water tank, thereby preventing the hydrogen concentration in the water tank from increasing.

[0011] In a fourth aspect, in any one of the first to third aspects, the toxic gas removal device is included in an ECLSS installed in a closed system that is closed from the outside, and gas may be introduced into the toxic gas removal device in a cabin of the closed system.

[0012] According to the above configuration, the toxic gas removal device included in the ECLSS can be used to treat the gases generated in the cabin and the fuel cell unit. In other words, there is no need to install separate toxic gas removal devices to treat the gases generated in the cabin and the fuel cell unit. This eliminates the need to install redundant equipment (toxic gas removal devices), and also eliminates the need for fuel to operate the equipment. This allows for the realization of a lightweight, fuel-efficient regenerative fuel cell system.

[0013] In a fifth aspect, in the fourth aspect, a water electrolysis device may be provided that electrolyzes the water in the water tank, and oxygen generated by the water electrolysis device may be supplied to the cabin and the fuel cell unit.

[0014] According to the above configuration, it is possible to eliminate the need to provide a duplicated device (oxygen tank) for supplying oxygen to the cabin or the fuel cell unit, thereby further reducing the mass of the regenerative fuel cell system. [Brief explanation of the drawings]

[0015] [Figure 1] 1 shows a regenerative fuel cell system according to a first embodiment. [Figure 2]The connection status of the ECLSS and fuel cell chamber is shown. [Figure 3] 1 shows a regenerative fuel cell system according to a second embodiment. [Figure 4] Indicates the connection status between the ECLSS and the water tank. [Figure 5] FIG. 10 shows a detailed view of a regenerative fuel cell system according to a second embodiment. [Figure 6] 10 shows a modified example of the regenerative fuel cell system of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] (First Example) 1 and 2, a regenerative fuel cell system 100 will be described. The regenerative fuel cell system 100 can be suitably used in environments closed off from the outside, such as space, polar regions, deserts, underground, and aircraft.

[0017] The regenerative fuel cell system 100 includes an ECLSS (Environmental Control and Life Support System) 2, a cabin (living space) 10, a hydrogen (H2) supply device 14, a fuel cell (FC) unit 18, a water tank 20, an ion exchanger 22, and a water electrolysis device 24. The ECLSS 2 includes a toxic gas removal device 8, a moisture removal device 6, a carbon dioxide (CO2) removal device 4, and an oxygen (O2) supply device 12. The fuel cell unit 18 is housed in a pressurized space. As shown in FIG. 2, the ECLSS 2 is disposed within the cabin 10.

[0018] The ECLSS 2 is a device that prepares the environment necessary for human life in space, for example, and removes gas-phase impurities such as carbon dioxide, water vapor, and off-gas (volatile components from equipment) generated within the cabin 10, and supplies air, water, etc. to the cabin 10. Specifically, emissions (waste) generated within the cabin 10 are supplied to a toxic gas removal device 8 within the ECLSS 2, where toxic gases are removed. The toxic gas removal device 8, for example, uses a catalyst to decompose and neutralize toxic gases. For example, this is done by applying a catalyst to a honeycomb structure and subjecting it to a heating oxidation reaction at 200 to 400°C.

[0019] The effluent from which toxic gases have been removed by the toxic gas removal device 8 is supplied to the moisture removal device 6, where moisture is removed. The moisture removal device 6 condenses and recovers moisture in the gas phase using a refrigerant at 4°C, for example. The effluent from which moisture has been removed is then supplied to the carbon dioxide removal device 4, where carbon dioxide is removed. The effluent from which carbon dioxide has been removed by the carbon dioxide removal device 4 is supplied again into the cabin 10. In other words, the ECLSS 2 can detoxify gases and the like generated in the cabin 10 and supply them again into the cabin 10.

[0020] The moisture removed by the moisture removal device 6 is supplied to the water tank 20 through the water discharge path 7. The pressure inside the water tank 20 is maintained at the same pressure as inside the cabin 10. Furthermore, in an environment where there is enough gravity to cause the water to fall downward, the water tank 20 may be located below the ECLSS 2 (moisture removal device 6). This allows the water collected in the cabin 10 to be supplied to the water tank 20 without using the power of a pump or the like.

[0021] The fuel cell unit 18 is disposed outside the cabin 10. The fuel cell unit 18 generates electricity for use in the regenerative fuel cell system 100. The fuel cell unit 18 generates electricity by utilizing a chemical reaction between oxygen supplied from the oxygen supply device 12 and hydrogen supplied from the hydrogen supply device 14. The basic principle of the fuel cell unit 18 is well known, and therefore a detailed description thereof will be omitted. The fuel cell unit 18 is housed in the fuel cell chamber 16 and is protected from the external environment. A temperature sensor 30, a pressure sensor 32, a hydrogen detection sensor 34, and an oxygen detection sensor 36 are disposed in the fuel cell chamber 16. The pressure in the fuel cell chamber 16 is maintained constant (e.g., 40 kPa·abs). Gas in the fuel cell chamber 16 is supplied to the toxic gas removal device 8. This prevents gas from accumulating in the fuel cell chamber 16. The gas in the fuel cell chamber 16 may include hydrogen, oxygen, carbon dioxide, water vapor, and the like that have permeated from the fuel cell unit 18.

[0022] As shown in FIGS. 1 and 2 , the fuel cell chamber 16 and the toxic gas removal device 8 are connected by a gas introduction flow path 28. A shutoff valve 26 is disposed in the gas introduction flow path 28. The shutoff valve 26 is configured by arranging two units, each with two valve bodies arranged in series, in parallel. This configuration allows communication with the ECLSS 2 to be maintained even if one shutoff valve 26 fails closed, as long as the parallel shutoff valve is in good condition. Alternatively, even if one shutoff valve 26 fails open, communication with the ECLSS 2 can be maintained as long as the serial shutoff valve 26 is in good condition. In other words, even if one shutoff valve 26 fails, the shutoff valve can still function as a shutoff valve. The shutoff valves 26 may be disposed within the cabin 10 and the fuel cell chamber 16, with only the gas introduction flow path 28 (i.e., the piping) located outside the cabin 10 and the fuel cell chamber 16 (external space). The shutoff valve 26 is of a normally closed type, and valve opening control is performed as needed. Specifically, the shutoff valve 26 opens for a predetermined period at a predetermined time. This allows the power consumption for controlling the shutoff valve 26 to be reduced.

[0023] The shutoff valve 26 may be controlled to open or close in accordance with the detected values ​​of the sensors 30, 32, 34, and 36 in the fuel cell chamber 16. For example, the shutoff valve 26 may open when the hydrogen detection sensor 34 detects an increase in the hydrogen concentration (or hydrogen pressure), and close when it detects a decrease in the hydrogen concentration. Alternatively, the shutoff valve 26 may be closed when the hydrogen detection sensor 34 exceeds the upper limit of its normal range. Alternatively, the shutoff valve 26 may be closed when either the temperature sensor 30 or the pressure sensor 32 exceeds the upper limit of its normal range.

[0024] The water produced in the fuel cell unit 18 and dissolved substances contained in the water are supplied to the water tank 20. After impurities are removed from the water in the water tank 20 by an ion exchanger 22, the water is supplied to a water electrolysis device 24. The water electrolysis device 24 electrolyzes the water to produce oxygen and hydrogen. The oxygen produced by the water electrolysis device 24 is supplied to the oxygen supply device 12, and the hydrogen is supplied to the hydrogen supply device 14. As described above, the fuel cell unit 18 generates electricity using the oxygen supplied from the oxygen supply device 12 and the hydrogen supplied from the hydrogen supply device 14. Note that a portion of the oxygen supplied to the oxygen supply device 12 is also supplied into the cabin 10. Therefore, the oxygen supply device 12 serves both as a component of the ECLSS 2 and as a device that supplies a raw material (oxygen) to the fuel cell unit 18.

[0025] As described above, in the regenerative fuel cell system 100, gas in the fuel cell chamber 16 is supplied to the toxic gas removal device 8, thereby preventing gas from accumulating in the fuel cell chamber 16. For example, if hydrogen accumulates in the fuel cell chamber 16, the hydrogen may cause hydrogen embrittlement of components and reduce safety. Furthermore, if oxygen accumulates in the fuel cell chamber 16, the oxygen may oxidize the components (causing the components to rust). By supplying the gas in the fuel cell chamber 16 to the toxic gas removal device 8, the regenerative fuel cell system 100 can prevent component deterioration and further improve safety. Furthermore, because the gas in the fuel cell chamber 16 is not discharged (purged) to the outside of the regenerative fuel cell system 100 and is regenerated as water, fuel (hydrogen, oxygen) for the fuel cell unit 18 can be saved.

[0026] Furthermore, the gas in the fuel cell chamber 16 is supplied to the toxic gas removal device 8 in the ECLSS 2. That is, in the regenerative fuel cell system 100, the toxic gas removal device 8 of the ECLSS 2 is used to treat the gas in the fuel cell chamber 16. Therefore, there is no need to provide a dedicated toxic gas removal device for treating the gas in the fuel cell chamber 16. The regenerative fuel cell system 100 does not require the installation of a redundant toxic gas removal device, and can reduce the size, weight, power consumption, etc. of the entire system.

[0027] Furthermore, in the regenerative fuel cell system 100, the fuel cell unit 18 is disposed outside the cabin 10, which prevents hydrogen in the fuel cell chamber 16 from entering the cabin 10. This improves safety within the cabin 10. Furthermore, because devices such as the shut-off valve 26 and sensors 30, 32, 34, and 36 are disposed inside the cabin 10 or the fuel cell chamber 16, these devices can be prevented from being exposed to the external environment. For example, when the regenerative fuel cell system 100 is used in space, the above-mentioned devices can be prevented from being exposed to harsh environments such as vacuum, cosmic rays, and low temperatures. This eliminates the need to take measures to protect the above-mentioned devices from harsh environments.

[0028] (Second Example) 3 and 4, a description will be given of regenerative fuel cell system 200. Regenerative fuel cell system 200 is a modified example of regenerative fuel cell system 100, and like regenerative fuel cell system 100, can be suitably used in environments closed off from the outside, such as space, polar regions, deserts, underground, and aircraft. In the following description, components common to regenerative fuel cell system 100 and regenerative fuel cell system 200 will be assigned the same reference numbers as those assigned to regenerative fuel cell system 100, and descriptions thereof may be omitted.

[0029] As shown in FIG. 3, in regenerative fuel cell system 200, gas in water tank 20 is supplied to toxic gas removal device 8. Regenerative fuel cell system 200 is a closed system in which water circulates within the system. As a result, impurity gases such as hydrogen and oxygen are mixed into the water in water tank 20. Regenerative fuel cell system 200 supplies gas in water tank 20 to toxic gas removal device 8, thereby preventing gas from accumulating within water tank 20.

[0030] As shown in FIG. 4, the water tank 20 and the toxic gas removal device 8 are connected by a gas introduction flow path 42. A shutoff valve 40 is disposed in the gas introduction flow path 42. The shutoff valve 40 is configured by arranging two units, each with two valve bodies arranged in series, in parallel. This allows communication with the ECLSS 2 to be maintained even if one shutoff valve 40 fails closed, as long as the parallel side is in good condition. Alternatively, even if one shutoff valve 40 fails open, communication with the ECLSS 2 can be maintained as long as the shutoff valve 40 on the series side is in good condition. In other words, even if one shutoff valve 40 fails, it can still function as a shutoff valve. The characteristics of the shutoff valve 40 are the same as those of the shutoff valve 26.

[0031] As described above, the water produced in the fuel cell unit 18 and dissolved substances contained in the water are supplied to the water tank 20. To improve drainage from the fuel cell unit 18 to the water tank 20, the pressure inside the water tank 20 is typically lower than the pressure inside the fuel cell unit 18. Therefore, gases dissolved in water in a high-pressure environment (fuel cell unit 18) become less soluble and more likely to desorb when transferred to a low-pressure environment (water tank 20) ​​(Henry's law). The regenerative fuel cell system 200 supplies gases in the water tank 20 to the toxic gas removal device 8, thereby preventing an increase in hydrogen concentration in the water tank 20.

[0032] Furthermore, in the regenerative fuel cell system 200, the toxic gas removal device 8 of the ECLSS 2 is used to treat the gas in the water tank 20. Therefore, there is no need to provide a dedicated toxic gas removal device for treating the gas in the water tank 20. The regenerative fuel cell system 200 does not require the installation of a redundant toxic gas removal device, and the size, weight, power consumption, etc. of the entire system can be reduced. Furthermore, because the gas in the water tank 20 is not discharged (purged) to the outside of the regenerative fuel cell system 200, the fuel (hydrogen, oxygen) of the fuel cell unit 18 can be saved.

[0033] Referring to FIG. 5, one embodiment of a regenerative fuel cell system 200 will be described in detail. FIG. 5 shows a regenerative fuel cell system 200 in which, instead of supplying oxidant gas directly from an oxygen storage system to a fuel cell system, the cabin atmosphere containing oxygen once supplied to the cabin is supplied as an oxidant to the fuel cell. The pressure inside the cabin 10 is controlled to 50 kPa and the temperature to 20 to 27°C. The air inside the cabin 10 is supplied to a filter 60. The filter 60 removes impurities (contaminants) contained in the air. The pressure inside the filter 60 is controlled to 50 kPa at room temperature. The air that passes through the filter 60 is supplied to a blower (compressor) 62. The blower 62 increases the air pressure to approximately 110 kPa. The blower 62 supplies air to the fuel cell unit 18 and a heat exchanger 68.

[0034] The inside of the fuel cell unit 18 is a pressure of 50 to 110 kPa, a temperature of 65°C, and a flow rate of 6 Nm 3 / h or less. In addition to air from a blower 62, hydrogen is supplied to the fuel cell unit 18 from a high-pressure hydrogen tank 52. The high-pressure hydrogen tank 52 corresponds to the hydrogen supply device 14 (see FIG. 3). In the fuel cell unit 18, electricity is generated using air (oxygen) and hydrogen.

[0035] The exhaust gas from the hydrogen electrode of the fuel cell unit 18 is supplied to a hydrogen electrode gas-liquid separator 66. In addition to hydrogen gas, water, impurities, etc. are also supplied to the hydrogen electrode gas-liquid separator 66. The hydrogen electrode gas-liquid separator 66 is located immediately after the stack, which is regulated to a pressure of 110 kPa or less and a temperature of 65°C, creating an environment similar to the conditions inside the stack. The gas phase (hydrogen) separated by the hydrogen electrode gas-liquid separator 66 is supplied to the fuel cell unit 18 by a hydrogen circulation pump 64 and used as a feedstock for power generation. The exhaust gas from the air electrode of the fuel cell unit 18 is supplied to a water tank 20. The water tank 20 functions both as a gas-liquid separator for the air electrode and as a water electrolysis tank with gas-liquid separation capabilities. The water tank 20 is supplied with the liquid phase (water and dissolved hydrogen) separated by the hydrogen electrode gas-liquid separator 66 and a mixed phase of nitrogen gas, oxygen gas, and water generated at the air electrode of the fuel cell unit 18. The pressure inside the water tank 20 is controlled to 80 kPa or less and a temperature of 60°C or less.

[0036] Water contained in the air from the blower 62 is also supplied to the water tank 20. Specifically, the cabin atmosphere is supplied from the blower 62 to a heat exchanger 68, which exchanges heat with cooling water at 4°C. Liquid water recovered by a dehumidifier 70 is then supplied to the water tank 20, and the dehumidified air is supplied to the ECLSS (toxic gas adsorption tower 72, CO2 adsorption tower 58, pressure regulator 56), where impurities are neutralized and the air is circulated within the cabin 10. The dehumidifier 70 is also provided with a refrigerant (not shown) at 4°C. Moisture in the air is cooled by the refrigerant and condenses into water. The water-air mixed phase produced by the dehumidifier 70 is supplied to the water tank 20. The dehumidifier 70 corresponds to the moisture removal device 6 (see FIG. 3).

[0037] The liquid phase separated in the water tank 20 is supplied to a dissolved impurities gasifier 78. The gas phase separated in the water tank 20 is supplied to a gas supply device 76. The liquid phase supplied to the dissolved impurities gasifier 78 includes water, dissolved nitrogen, dissolved oxygen, and dissolved hydrogen. The dissolved impurities gasifier 78 separates the gas and water contained in the liquid phase. The water (including dissolved oxygen) separated by the dissolved impurities gasifier 78 is supplied to a water pump 80. The water pump 80 supplies the water supplied from the dissolved impurities gasifier 78 to the water electrolysis device 24.

[0038] The water electrolysis device 24 electrolyzes water to produce oxygen and hydrogen. The hydrogen produced by the water electrolysis device 24 is supplied to a high-pressure hydrogen tank 52. The high-pressure hydrogen tank 52 supplies hydrogen to the fuel cell unit 18. The oxygen (including the water mixed phase) produced by the water electrolysis device 24 is supplied to an oxygen gas-liquid separator 81, and the gas phase is supplied to a high-pressure oxygen tank 50 and the liquid phase is supplied to the water tank 20. The high-pressure oxygen tank 50 corresponds to the oxygen supply device 12 (see FIG. 3).

[0039] The gas phase (nitrogen, oxygen, trace amounts of hydrogen, and other impurities) separated in the water tank 20 and the gas phase (trace amounts of nitrogen, trace amounts of hydrogen, and other impurities) separated in the dissolved impurity gasifier 78 are supplied to a gas supply device 76. The pressure inside the gas supply device 76 is controlled to 80 kPa or less and the temperature to 80°C or less. The gas supply device 76 supplies gas to a heat exchanger 74. The heat exchanger 74 is connected to a toxic gas oxidation catalyst 79, and heat exchange is performed by supplying gas to the toxic gas oxidation catalyst 79 and receiving gas from the hydrogen removal catalyst 79. The pressure inside the toxic gas oxidation catalyst 79 is controlled to 80 kPa and the temperature to 400°C. The toxic gas oxidation catalyst 79 removes the hydrogen supplied from the heat exchanger 74. The hydrogen removed by the toxic gas oxidation catalyst 79 is discarded as water. The heat exchanger 74 circulates the gas through the toxic gas oxidation catalyst 79, thereby effectively exchanging heat between the gases upstream and downstream of the toxic gas oxidation catalyst 79. For example, it raises the temperature of gas below 80°C to above 400°C, and lowers the temperature of gas at 400°C to below 95°C.

[0040] The air that has passed through the heat exchanger 74 is supplied to the pressure regulator 56. Air from which moisture has been removed by a dehumidifier 70 is supplied to the pressure regulator 56 either directly or after passing through a carbon dioxide adsorption tower 58 or a toxic gas adsorption tower 72. The temperature inside the carbon dioxide adsorption tower 58 is controlled to room temperature. The carbon dioxide adsorption tower 58 corresponds to the carbon dioxide removal device 4 (see Figure 3). The temperature inside the toxic gas adsorption tower is controlled to 20°C and the flow rate is 15.3 m 3 / h. The pressure regulator 56 controls the pressure of the air supplied from the heat exchanger 74, dehumidifier 70, carbon dioxide adsorption tower 58, and toxic gas adsorption tower 72, and by controlling the pressure regulator 56 and the pressure regulating valve 54, the cabin pressure is adjusted to 50 kPa.

[0041] Oxygen supplied from the water electrolysis device 24 to the high-pressure oxygen tank 50 is supplied to the pressure regulating valve 54. Nitrogen is also supplied to the pressure regulating valve 54 from a high-pressure nitrogen tank 82. The pressure regulating valve 54 mixes the high-pressure oxygen tank 50 and the high-pressure nitrogen tank 82, and adjusts the cabin pressure to 50 kPa by controlling the pressure regulator 56 and the pressure regulating valve 54. The inside of the pressure regulating valve 54 is at room temperature. Air from the pressure regulator 56 and the pressure regulating valve 54 is supplied into the cabin 10.

[0042] As described above, in the regenerative fuel cell system 200, the air inside the cabin 10 is supplied to the fuel cell unit 18. This simplifies the structure for supplying oxygen (air) to the fuel cell unit 18, thereby simplifying the fuel cell system. Furthermore, the filter 60 and blower 62 for supplying air to the air electrode of the fuel cell unit 18 are the same as the filter 60 and blower 62 for circulating air in the ECLSS 2. In other words, the fuel cell system and the ECLSS 2 use the same filter 60 and blower 62. This allows for a reduction in the number of parts in the regenerative fuel cell system 200, and also allows for a reduction in the weight of the regenerative fuel cell system 200.

[0043] Furthermore, the air inside the cabin 10 contains nitrogen. Therefore, the air supplied to the cathode of the fuel cell unit 18 also contains nitrogen. A fuel cell unit in which nitrogen-containing air is supplied to the cathode is used as a fuel cell unit for ground vehicles that is currently under development. By adopting a structure in which the air inside the cabin 10 is supplied to the fuel cell unit 18, it is possible to use the technology of fuel cell units for ground vehicles that are currently under development as the fuel cell unit 18. Furthermore, by using the heat exchanger 74, it is also possible to reduce the power consumption of the ECLSS 2.

[0044] Regenerative fuel cell system 200a will be described with reference to Figure 6. Regenerative fuel cell system 200a is a modified example of regenerative fuel cell system 200, and differs from regenerative fuel cell system 200 in the structure for supplying oxygen to the cathode of fuel cell unit 18. In the following description, for regenerative fuel cell system 200a, components common to regenerative fuel cell system 200 will be assigned the same reference numbers as those assigned to regenerative fuel cell system 200, and descriptions thereof may be omitted.

[0045] In the regenerative fuel cell system 200a, air inside the cabin 10 is not supplied to the fuel cell unit 18, but oxygen (pure oxygen) is supplied to the fuel cell unit 18 from a high-pressure oxygen tank 50. Hydrogen in a high-pressure hydrogen tank 52 is supplied to the fuel cell unit 18 through a hydrogen ejector 92. Also, oxygen in the high-pressure oxygen tank 50 is supplied to the fuel cell unit 18 through an oxygen ejector 90. Furthermore, an oxygen electrode gas-liquid separator 94, a cabin gas-liquid separator 96, an oxygen electrode water tank 20a, and a hydrogen electrode water tank 20b are provided separately (see FIG. 5 for comparison).

[0046] The cabin gas-liquid separator 96 is supplied with the air and water mixed phase generated by the dehumidifier 70. The cabin gas-liquid separator 96 separates the air and water mixed phase supplied from the dehumidifier 70 into a gas phase (air) and a liquid phase (water, dissolved air). The gas phase separated by the cabin gas-liquid separator 96 is supplied to the pressure regulator 56. In the regenerative fuel cell system 200a, the inside of the heat exchanger 68 and the dehumidifier 70 is maintained at a pressure of 50 kPa, a temperature of 20°C or higher, and a flow rate of 400 to 1000 m 3 / h. In the regenerative fuel cell system 200a, gas is not supplied from the dehumidifier 70 to the carbon dioxide adsorption tower 58, but is supplied from the heat exchanger 68 to the carbon dioxide adsorption tower 58. Furthermore, gas is also supplied from the heat exchanger 68 to the hydrogen removal catalyst 72.

[0047] In the regenerative fuel cell system 200a, exhaust gas (hydrogen, carbon dioxide, water, etc.) from the hydrogen electrode of the fuel cell unit 18 is supplied to the hydrogen electrode gas-liquid separator 66 and separated into a gas phase and a liquid phase. The gas phase (hydrogen, carbon dioxide, etc.) separated in the hydrogen electrode gas-liquid separator 66 is returned to the hydrogen ejector 92 and supplied again to the fuel cell unit 18. The liquid phase (water, dissolved carbon dioxide, dissolved hydrogen, etc.) separated in the hydrogen electrode gas-liquid separator 66 is supplied to the hydrogen electrode water tank 20b. In addition, exhaust gas (oxygen, water, etc.) from the oxygen electrode of the fuel cell unit 18 is supplied to the oxygen electrode gas-liquid separator 94 and separated into a gas phase and a liquid phase. The gas phase (oxygen, etc.) separated in the oxygen electrode gas-liquid separator 94 is returned to the oxygen ejector 90 and supplied again to the fuel cell unit 18. The liquid phase (water, dissolved oxygen, etc.) separated in the oxygen electrode gas-liquid separator 94 is supplied to the oxygen electrode water tank 20a.

[0048] In addition to the liquid phase separated in the oxygen electrode gas-liquid separator 94, the liquid phase (water, dissolved air) separated in the cabin gas-liquid separator 96 is also supplied to the oxygen electrode water tank 20a. The oxygen electrode water tank 20a has a gas-liquid separation function, and the gas phase (oxygen, carbon dioxide, water vapor, nitrogen, etc.) separated in the oxygen electrode water tank 20a is supplied to the heat exchanger 68. In addition, the liquid phase (water, dissolved carbon dioxide, dissolved nitrogen, etc.) separated in the oxygen electrode water tank 20a is supplied to the dissolved impurities gasification device 78.

[0049] The liquid phase (water, dissolved carbon dioxide, dissolved hydrogen, etc.) separated in the hydrogen electrode gas-liquid separator 66 is supplied to the hydrogen electrode water tank 20b. The hydrogen electrode water tank 20b has a gas-liquid separation function, and the gas phase (hydrogen, water vapor, carbon dioxide, nitrogen, etc.) separated in the hydrogen electrode water tank 20b is supplied to a gas supply device 76. In addition, the liquid phase (water, dissolved carbon dioxide, dissolved nitrogen, etc.) separated in the hydrogen electrode water tank 20b is supplied to a dissolved impurities gasification device 78.

[0050] In the regenerative fuel cell system 200a, air inside the cabin 10 is not supplied to the fuel cell unit 18, but oxygen (pure oxygen) from a high-pressure oxygen tank 50 is supplied to the fuel cell unit 18. Therefore, the regenerative fuel cell system 200a can omit or simplify devices that prevent nitrogen from entering the water electrolysis device 24, and can reduce the amount of nitrogen gas to be installed. In addition, valves, regulators, etc. for oxygen supply can be shared, which can also reduce the weight of the system.

[0051] In the first and second embodiments, the fuel cell unit 18 is disposed outside the cabin 10, but the fuel cell unit 18 may be disposed inside the cabin 10.

[0052] In the above first and second embodiments, the pressure inside the water tank 20 is maintained at the same level as the pressure inside the cabin 10, and the water tank 20 is disposed below the ECLSS 2. However, the pressure inside the water tank 20 may be maintained at a lower pressure than the pressure inside the cabin 10. This allows the water inside the moisture removal device 6 to be supplied to the water tank 20 more reliably.

[0053] In the second embodiment described above, an example was described in which gas in the water tank 20 is supplied to the toxic gas removal device 8. However, in addition to the gas in the water tank 20, gas in the fuel cell chamber 16 may also be supplied to the toxic gas removal device 8. In this case, the gas introduction flow path 28 and shut-off valve 26 described in the first embodiment are applied to the regenerative fuel cell system 200, and the fuel cell chamber 16 and the toxic gas removal device 8 are connected.

[0054] In the second embodiment, an ion exchanger may be connected to the pipe supplying the liquid phase to the water tanks 20a, 20b. This improves the purity of the water in the water tanks 20a, 20b. Furthermore, a trapping device may be provided upstream of the high-pressure oxygen tank 50 and / or the high-pressure hydrogen tank 52 to prevent carbon dioxide, nitrogen, and the like from dissolving. For example, carbon dioxide may be trapped as dry ice during the process of storing liquefied oxygen, or nitrogen may be returned to the cabin 10 through a nitrogen-permeable membrane after water electrolysis.

[0055] In the second embodiment, the pressure in the oxygen electrode water tank 20a may be maintained higher than the pressure in the cabin 10, and the supply of the liquid phase from the cabin gas-liquid separator 96 to the oxygen electrode water tank 20a may be stopped before the pressures in the two tanks become equal. In either case, by performing such control, it is possible to reduce the amount of nitrogen entering the oxygen electrode water tank 20a.

[0056] Although the embodiments of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Furthermore, the technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings simultaneously achieves multiple objectives, and achieving one of these objectives itself has technical utility. [Explanation of symbols]

[0057] 7: Water discharge path, 8: Toxic gas removal device, 16: Fuel cell chamber, 18: Fuel cell unit, 20: Water tank, 26, 42: Gas introduction flow path, 100, 200: Regenerative fuel cell system

Claims

1. a fuel cell unit; a fuel cell chamber housing the fuel cell unit; a water tank for storing water discharged from the fuel cell unit; a toxic gas removal device into which gas from an arbitrary location is introduced through a gas introduction passage; a water discharge flow path for discharging water generated in the toxic gas removal device to the water tank; A regenerative fuel cell system comprising:

2. 2. The regenerative fuel cell system according to claim 1, wherein gas generated in the fuel cell chamber is introduced into the toxic gas removal device.

3. 2. The regenerative fuel cell system according to claim 1, wherein gas generated in the water tank is introduced into the gas removal device.

4. The toxic gas removal device is included in an ECLSS that is installed in a closed system that is closed from the outside, 4. The regenerative fuel cell system according to claim 1, wherein gas is introduced into the toxic gas removal device in a cabin of the closed system.

5. a water electrolysis device that electrolyzes the water in the water tank; 5. The regenerative fuel cell system according to claim 4, wherein oxygen generated in the water electrolysis device is supplied to the cabin and the fuel cell unit.

Images