Fuel supply system and fuel cell unit

Abstract

To reduce power generation cost in a fuel cell unit.SOLUTION: A hydrogen supply system 20 is configured to be capable of supplying hydrogen gas as a fuel to a separator 12 of a fuel battery cell 10 in which a plurality of layers of laminated objects comprising a separator 11 where first gas (air) containing an oxidant passes, a separator 12 where second gas (hydrogen gas) containing hydrogen passes, an MEA 13, and the like are laminated to be integrated and which is configured to be capable of generating electricity by causing reaction of the air and the hydrogen gas. The hydrogen supply system includes: a hydrogen generation apparatus 21 generating hydrogen by electrolysis of raw water to generate hydrogen gas; a gas-liquid separation tank 22 separating, from exhaust gas discharged from the separator 11, water contained in the exhaust gas and recovering the water; and an ion exchange treatment device 25 subjecting water recovered by the gas-liquid separation tank 22 to ion exchange treatment. The hydrogen supply system is configured such that water discharged from the separator 11 together with the exhaust gas by the power generation in the cell 10 is subjected to ion exchange treatment performed by the treatment device 25 to be supplied to the generation apparatus 21.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fuel supply system configured to be able to generate a gas containing hydrogen and supply it to a fuel cell unit, and to a fuel cell unit configured including such a fuel supply system. [Background technology]

[0002] For example, the following patent document discloses an energy supply system (hereinafter, also simply referred to as "the system") configured to enable hydrogen and oxygen generated in a hospital to be utilized in hospitals, hydrogen stations, homes, etc. Specifically, this system is configured to include a power generation unit that generates electricity (performs solar power generation), a pure water storage unit that stores water (pure water) generated by an electrically regenerative pure water generation device, an electrolysis device that electrolyzes water using the electricity generated in the power generation unit, a hydrogen tank that stores hydrogen generated in the electrolysis device, an oxygen tank that stores oxygen generated in the electrolysis device, a fuel cell that generates electricity using hydrogen, and an oxygen supply device that provides oxygen for oxygen inhalation.

[0003] In this case, the hydrogen produced in the electrolyzer is supplied to a hydrogen station, which is a hydrogen supply facility, and stored in a hydrogen tank, and is then supplied from the hydrogen station to a fuel cell for power generation. Also, the oxygen produced in the electrolyzer is stored in an oxygen tank of an oxygen supply device and used for medical purposes in the hospital. In this way, this system makes it possible to effectively utilize the oxygen obtained by electrolysis of water in the electrolyzer together with the hydrogen. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-047417 A (Pages 3-5, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0005] However, the system disclosed in the above-mentioned patent document has the following problems to be solved.

[0006] Specifically, the above system employs a configuration in which water (pure water) produced by an electrically regenerated pure water production device is stored in a pure water storage section, and the stored water is supplied to an electrolysis device for electrolysis to obtain hydrogen to be used in power generation in a fuel cell. In this case, the system employs a configuration in which the electrically regenerated pure water production device produces water (pure water) to be used as a raw material in an electrolysis device that produces hydrogen to be used in a fuel cell for power generation. In other words, this system consumes electricity when producing water to obtain hydrogen required for power generation, which causes a problem in that the cost of producing hydrogen rises and makes it difficult to reduce power generation costs.

[0007] The present invention has been made in consideration of the above problems to be solved, and has as its main object to provide a fuel supply system and a fuel cell unit that can reduce the power generation cost. [Means for solving the problem]

[0008] In order to achieve the above object, the fuel supply system described in claim 1 is a fuel supply system configured to be capable of supplying the second gas as fuel to the second separator of a fuel cell main body, which is configured to generate power by reacting the first gas with the second gas via the membrane electrode assembly, and which includes a first separator through which a first gas containing an oxidant is passed, a second separator through which a second gas containing hydrogen is passed, and a membrane electrode assembly disposed between the first separator and the second separator, and which is stacked and integrated in multiple layers and is configured to be capable of generating power by reacting the first gas with the second gas via the membrane electrode assembly. The fuel supply system includes a generation device that electrolyzes raw material water to generate the hydrogen and generate the second gas, a first recovery device that separates and recovers water contained in the exhaust gas discharged from the first separator from the exhaust gas, and a treatment device that performs ion exchange treatment on the water recovered by the first recovery device, and is configured to be capable of ion exchange treatment on the water discharged from the first separator together with the exhaust gas due to power generation in the fuel cell main body, and supply the water to the generation device as the raw material.

[0009] The fuel supply system of claim 2 is the fuel supply system of claim 1, further comprising a second recovery device which separates and recovers water discharged from the generation device together with oxygen generated by electrolysis from the oxygen, and is configured so that the water recovered by the second recovery device can be subjected to ion exchange treatment by the treatment device and supplied to the generation device as the raw material.

[0010] The fuel supply system of claim 3 is the fuel supply system of claim 2, which is configured to be able to supply the oxygen separated in the second recovery device to the first separator in the fuel cell main body.

[0011] In addition, the fuel supply system described in claim 4 is the fuel supply system described in claim 1, further comprising a third recovery device that separates and recovers water contained in the second gas generated by the generation device from the second gas, and is configured to subject the water recovered by the third recovery device to ion exchange treatment by the treatment device and supply it to the generation device as the raw material.

[0012] Furthermore, the fuel cell unit described in claim 5 includes the fuel supply system described in any one of claims 1 to 4, the fuel cell main body formed by stacking and integrating a plurality of flat plate-shaped laminated objects including at least the first separator, the second separator, and the membrane electrode assembly, and a gas supply device that supplies the first gas to the first separator. Effect of the Invention

[0013] The fuel supply system described in claim 1 includes a generator that electrolyzes raw water to generate hydrogen and generate a second gas, a first recovery device that separates and recovers water contained in exhaust gas discharged from a first separator of the fuel cell main body from the exhaust gas, and a treatment device that performs ion exchange treatment on the water recovered by the first recovery device, and is configured so that the water discharged from the first separator together with the exhaust gas due to power generation in the fuel cell main body can be ion exchanged by the treatment device and supplied as raw material to the generator. Also, the fuel cell unit described in claim 5 includes the above fuel supply system, the fuel cell main body, and a gas supply device.

[0014] Therefore, according to the fuel supply system described in claim 1 and the fuel cell unit described in claim 5, unlike a configuration in which water (pure water) used as a raw material in an electrolysis device that produces hydrogen is produced by an electrically regenerated pure water production device, by using water discharged from the fuel cell main body (first separator) during power generation as a raw material for generating hydrogen in the production device, no electricity is required to produce the raw water, thereby making it possible to sufficiently reduce the cost of generating hydrogen, and thereby making it possible to sufficiently reduce the cost of generating electricity by the fuel cell unit using the produced hydrogen.

[0015] The fuel supply system described in claim 2 includes a second recovery device that separates water discharged from the generator together with oxygen generated by electrolysis from the oxygen and recovers the water, and is configured to subject the water recovered by the second recovery device to ion exchange treatment by a treatment device and supply it to the generator as a raw material. Therefore, according to the fuel supply system described in claim 2 and the fuel cell unit including the same, water droplets (liquid water) discharged from the generator together with oxygen generated by electrolysis during the generation of hydrogen (hydrogen gas) in the generator can be used as a raw material in the generator, thereby ensuring a sufficient amount of water required for hydrogen generation.

[0016] In addition, the fuel supply system according to claim 3 is configured to be able to supply the oxygen separated in the second recovery device to the first separator in the fuel cell main body. Therefore, according to the fuel supply system according to claim 3 and the fuel cell unit including the same, compared to a configuration in which only the atmosphere (air) is supplied as the first gas to the first separator in the fuel cell main body, the oxygen generated in the generator is supplied to the first separator, and the first gas having a sufficiently high oxygen concentration is reacted with the second gas to generate electricity efficiently. Also, for example, compared to a configuration in which the oxygen generated in the generator is simply released into the atmosphere, it is possible to preferably avoid a situation in which an unintended oxidation reaction (fire, etc.) occurs.

[0017] The fuel supply system according to claim 4 includes a third recovery device that separates and recovers water contained in the second gas generated by the generator, and is configured to perform ion exchange processing on the water recovered by the third recovery device using a processing device and supply it to the generator as a raw material. Therefore, the fuel supply system according to claim 4 and the fuel cell unit including the same can not only ensure a sufficient amount of water to be used as a raw material in the generator, but also prevent a large amount of water droplets (liquid water) discharged from the generator together with the second gas generated in the generator from being supplied to the fuel cell main body (second separator) and causing the passage resistance of hydrogen gas in the second separator to become excessively large, thereby enabling the fuel cell main body to generate electricity appropriately. [Brief description of the drawings]

[0018] [Figure 1] 1 is a configuration diagram showing the configuration of a fuel cell unit 1. FIG. [Diagram 2] FIG. 2 is a diagram showing the configuration of a fuel cell unit 1A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a fuel supply system and a fuel cell unit will be described with reference to the accompanying drawings.

[0020] 1 is an example of a "fuel cell unit" and is configured to generate electricity by reacting gases for power generation (air (atmosphere: oxygen), which is an example of a "first gas containing an oxidant," and hydrogen gas, which is an example of a "second gas containing hydrogen"). Specifically, the fuel cell unit 1 includes a pump 2, a post-treatment device 3, pipes 4a-4i, 5a-5d, a control unit 6, fuel cell 10, and a hydrogen supply system 20.

[0021] In this case, the fuel cell 10 is an example of a "fuel cell body configured to generate electricity by reacting a first gas with a second gas," and includes a power generation stack made up of separator 11, which is an example of a "first separator," separator 12, which is an example of a "second separator," and MEA 13, which is an example of a "membrane electrode assembly (membrane electrode assembly for fuel cells)," a separator (not shown) for passing a cooling fluid (air or coolant), and end plates (not shown) disposed at both ends in the stacking direction of each laminate. In this example, the plates such as separators 11 and 12, MEA 13, the cooling separator, and the end plates correspond to "plural flat plate-shaped laminated objects," and the fuel cell 10 is configured by stacking and integrating these.

[0022] Separator 11 has a groove (not shown) for passing air (atmosphere), and separator 12 has a groove (not shown) for passing hydrogen gas, and these are laminated so that MEA 13 is sandwiched between separators 11 and 12. As a result, air flow path 11c is formed by the groove of separator 11 and one surface of MEA 13, and separator 11 functions as an anode (air electrode: oxygen electrode), and hydrogen flow path 12c is formed by the groove of separator 12 and the other surface of MEA 13, and separator 12 functions as a cathode (hydrogen electrode). MEA 13 is composed of an electrolyte membrane, a catalyst layer, a gas diffusion layer, and the like.

[0023] In addition, an actual fuel cell 10 is configured to include multiple of the above-mentioned power generation stacks and cooling separators depending on the power generation capacity required of the fuel cell unit 1, but in order to facilitate understanding of the configuration and operation of the fuel cell unit 1, only one power generation stack is shown, and illustrations and descriptions of the cooling separators and end plates are omitted.

[0024] The hydrogen supply system 20 is an example of a “fuel supply system” and includes a hydrogen generation device 21, gas-liquid separation tanks 22, 23a, and 23b, switching valves 24a and 24b, and an ion exchange treatment device 25.

[0025] The hydrogen generation device 21 is an example of a "generation device that generates hydrogen to generate a second gas", and is configured to generate hydrogen by performing an electrolysis process using water recovered in the gas-liquid separation tanks 22, 23a, and 23b as a "raw material" as described later, and to supply the generated hydrogen (hydrogen gas) to the separator 12 of the fuel cell 10 as a "second gas: fuel". As described later, the fuel cell unit 1 of this example is configured to supply oxygen generated by electrolysis (generation of hydrogen) in the hydrogen generation device 21 to the separator 11 of the fuel cell 10 as a part of the "first gas". As described later, the fuel cell unit 1 of this example employs a configuration in which water is pressure-fed from the gas-liquid separation tank 23a to the ion exchange treatment device 25 by utilizing the pressure of oxygen exhausted from the hydrogen generation device 21, and water is pressure-fed from the gas-liquid separation tank 23b to the ion exchange treatment device 25 by utilizing the pressure of hydrogen (hydrogen gas) exhausted from the hydrogen generation device 21.

[0026] The gas-liquid separation tank 22 is an example of a "first recovery device" and is configured to be able to separate and recover water contained in the exhaust gas discharged from the separator 11 from the exhaust gas. In this case, when generating electricity in the fuel cell 10, air (oxygen) passing through the air flow passage 11c reacts with hydrogen gas (hydrogen) passing through the hydrogen flow passage 12c to generate water in the air flow passage 11c, and this water is discharged from the separator 11 together with the exhaust gas (air reacted with hydrogen). Therefore, in the fuel cell unit 1 of this example, a configuration is adopted in which this water is recovered in the gas-liquid separation tank 22 and the recovered water is supplied to the hydrogen generation device 21 as a "raw material".

[0027] Moreover, the gas-liquid separation tank 23a is an example of a "second recovery device" and is configured to be able to separate and recover water discharged from the hydrogen generation device 21 together with oxygen generated by electrolysis in the hydrogen generation device 21. In this case, when hydrogen is produced in the hydrogen generation device 21, water that was not electrolyzed is discharged from the hydrogen generation device 21 together with oxygen. Therefore, the fuel cell unit 1 of this example is configured to recover this water in the gas-liquid separation tank 23a and supply the recovered water to the hydrogen generation device 21 as a "raw material".

[0028] The gas-liquid separation tank 23b is an example of a "third recovery device" and is configured to be able to separate and recover water contained in the hydrogen gas (second gas) generated by the hydrogen generation device 21 from the hydrogen gas. In this case, when hydrogen is generated in the hydrogen generation device 21, water that is not electrolyzed is discharged from the hydrogen generation device 21 together with the hydrogen. Therefore, the fuel cell unit 1 of this example is configured to recover this water in the gas-liquid separation tank 23b and supply the recovered water to the hydrogen generation device 21 as a "raw material".

[0029] In this case, in each of the gas-liquid separation tanks 22, 23a, 23b, the water that flows into the tank together with the gas (air, oxygen, or hydrogen) through the pipes 4c, 4h, and 4e drips down to the bottom of the tank by its own weight and is collected in the tank, and when a predetermined amount of water is stored in the tank, the control unit 6 switches the switching valves 24a and 24b to control the switching of the valves 24a and 24b, so that the water is discharged from the tank through the pipes 5a to 5c connected to the bottom by the pressure applied to the tank (the inflow pressure of the gas and water from the pipes 4c, 4h, and 4e). In addition, in each of the gas-liquid separation tanks 22, 23a, and 23b, the gas (air, oxygen, or hydrogen) from which moisture has been separated is discharged from the tank through the pipes 4d, 4i, and 4f connected to the upper part. In addition, pipes 4c, 4h, and 4e are connected at a position higher than the water level in the tank when a predetermined amount of water is stored in the tank as described above, and lower than the connection points of pipes 4d, 4i, and 4f, respectively.

[0030] The switching valve 24a, under the control of the control unit 6, allows / restricts the flow of water separated in the gas-liquid separation tank 23a into the ion exchange treatment device 25. In addition, the switching valve 24b, under the control of the control unit 6, allows / restricts the flow of water separated in the gas-liquid separation tank 23b into the ion exchange treatment device 25.

[0031] The ion exchange treatment device 25 is an example of a "treatment device" and is configured to perform ion exchange treatment on the water separated from air in the gas-liquid separation tank 22, the water separated from oxygen in the gas-liquid separation tank 23a, and the water separated from hydrogen gas in the gas-liquid separation tank 23b, and to supply the water as a "raw material" to the hydrogen generation device 21. Specifically, the ion exchange treatment device 25 includes, as an example, an anion exchange resin filter, and removes SO from the water that is allowed to pass through the filter. 4 2- It is configured to be able to remove (sulfate ions).

[0032] In this case, the water discharged from separator 11 together with air and recovered in gas-liquid separation tank 22 is acidic with a pH of about 2. In addition, the water discharged from hydrogen generation apparatus 21 together with oxygen and recovered in gas-liquid separation tank 23a, and the water discharged from hydrogen generation apparatus 21 together with hydrogen and recovered in gas-liquid separation tank 23b are also acidic with a pH of about 4. Therefore, by subjecting these waters to ion exchange treatment in ion exchange treatment device 25 prior to supplying them to hydrogen generation apparatus 21, it is possible to avoid deterioration of metal parts and piping within the apparatus and to improve the efficiency of the electrolysis treatment in hydrogen generation apparatus 21.

[0033] On the other hand, the pump 2 is an example of a "gas supply device that supplies a first gas to the first separator", and pressure-feeds (supplies) air into the air flow path 11c of the separator 11 under the control of the control unit 6. As will be described later, the fuel cell unit 1 of this example employs a configuration in which water is pressure-feeded from the gas-liquid separation tank 22 to the ion exchange treatment device 25 by utilizing the pressure of the air discharged from the separator 11 (air flow path 11c) by the pressure-feeding of air by the pump 2.

[0034] The post-treatment device 3 is composed of a recovery device that removes (recovers) hydrogen contained in the gas (exhaust containing unreacted hydrogen in the fuel cell 10) that is exhausted from the separator 12 after being reacted with air (oxygen) in the air flow path 11c in the hydrogen flow path 12c of the separator 12, and a mixer that mixes air (atmosphere) (diluting the exhaust from the separator 12) so that the hydrogen concentration in the gas exhausted from the separator 12 falls below a predetermined value. Note that when the hydrogen concentration in the exhausted gas is sufficiently low, the post-treatment device 3 may be unnecessary.

[0035] The pipe 4a is connected to an air supply port of the pump 2, and one end of the pipe 4a is connected to the atmosphere via a dust filter (not shown). The pipe 4b connects the exhaust port of the pump 2 to the pipe connection part 11a (inlet) of the separator 11, and guides the air pumped by the pump 2 to the separator 11. The pipe 4c connects the pipe connection part 11b (outlet) of the separator 11 to the gas-liquid separation tank 22, and guides the air exhausted from the separator 11 to the gas-liquid separation tank 22. The pipe 4d is connected to the upper part of the gas-liquid separation tank 22 as described above, and one end of the pipe 4d is connected to the atmosphere so that the air from which moisture has been separated (moisture removed) in the gas-liquid separation tank 22 can be released to the atmosphere.

[0036] The pipe 4e guides the hydrogen gas generated in the hydrogen generation device 21 to the gas-liquid separation tank 23b. The pipe 4f, as described above, connects the exhaust port provided at the top of the gas-liquid separation tank 23b to the pipe connection part 12a (inlet) of the separator 12, and guides the hydrogen gas from which moisture has been separated (from which moisture has been removed) in the gas-liquid separation tank 23b to the separator 12. The pipe 4g connects the pipe connection part 12b (exhaust port) of the separator 12 to the post-treatment device 3, and guides the gas exhausted from the separator 12 (hydrogen gas after the reaction in the fuel cell 10) to the post-treatment device 3.

[0037] The pipe 4h guides the oxygen generated in the hydrogen generation apparatus 21 to the gas-liquid separation tank 23a. The pipe 4i connects the exhaust port provided at the top of the gas-liquid separation tank 23a to the above-mentioned pipe 4a, as described above, and causes the oxygen from which moisture has been separated (from which moisture has been removed) in the gas-liquid separation tank 23a to flow into the separator 11 via the pipe 4a, the pump 2, and the pipe 4b.

[0038] The pipe 5a is a pipe that connects a drainage outlet provided at the bottom of the gas-liquid separation tank 22 to the ion exchange treatment device 25 as described above, and guides the water separated in the gas-liquid separation tank 22 to the ion exchange treatment device 25. The pipe 5b is a pipe that connects a drainage outlet provided at the bottom of the gas-liquid separation tank 23a to the pipe 5a as described above, and allows the water separated in the gas-liquid separation tank 23a to flow into the pipe 5a. The pipe 5c is a pipe that connects a drainage outlet provided at the bottom of the gas-liquid separation tank 23b to the pipe 5a as described above, and guides the water separated in the gas-liquid separation tank 23b to the ion exchange treatment device 25 via the pipe 5a. The pipe 5d is a pipe that connects the ion exchange treatment device 25 to the hydrogen generation device 21, and guides the water ion-exchanged in the ion exchange treatment device 25 to the hydrogen generation device 21.

[0039] The control unit 6 comprehensively controls the fuel cell unit 1. Specifically, the control unit 6 is an example of a "control unit" and controls the pump 2 to supply air to the fuel cell 10 (separator 11), and controls the hydrogen generation device 21 of the hydrogen supply system 20 to generate hydrogen gas and supply it to the fuel cell 10 (separator 12), thereby generating electricity in the fuel cell 10.

[0040] Moreover, as one example, the control unit 6 controls the switching valves 24a, 24b so as to normally restrict the inflow of water from the gas-liquid separation tank 23a through the pipe 5b into the pipe 5a and restrict the inflow of water from the gas-liquid separation tank 23b through the pipe 5c into the pipe 5a, while permitting the inflow of water from the gas-liquid separation tank 22 into the ion exchange treatment device 25 through the pipe 5a. Moreover, the control unit 6 controls the switching valve 24a to permit the inflow of water from the pipe 5b into the pipe 5a when the amount of water separated from oxygen in the gas-liquid separation tank 23a reaches a specified amount, and controls the switching valve 24b to permit the inflow of water from the pipe 5c into the pipe 5a when the amount of water separated from hydrogen gas in the gas-liquid separation tank 23b reaches a specified amount.

[0041] As described above, in this fuel cell unit 1, air (atmospheric air: oxygen) and hydrogen generated in the hydrogen generation device 21 of the hydrogen supply system 20 are reacted in the fuel cell 10 to generate electricity. In the hydrogen generation device 21, hydrogen is generated by electrolysis using as "raw materials" water generated in the fuel cell 10 (separator 11) during power generation and water generated in the hydrogen generation device 21 during hydrogen generation (water discharged together with oxygen and water discharged together with hydrogen). Therefore, during initial operation immediately after installation of the fuel cell unit 1 or when starting operation after a long period of suspension (when there is not enough water in the gas-liquid separation tanks 22, 23a, 23b), water (raw material) for generating hydrogen required to start power generation is injected into the hydrogen generation device 21.

[0042] In this state, when an instruction to start power generation is given by operating an operation unit (not shown), the control unit 6 controls the hydrogen generation device 21 to start generating hydrogen. In response, the hydrogen generation device 21 electrolyzes water as a raw material to generate hydrogen, and discharges the generated hydrogen (hydrogen gas) to the pipe 4e and also discharges oxygen generated by electrolysis to the pipe 4h.

[0043] At this time, in this type of hydrogen generating device, a part of the water as a raw material is discharged together with the hydrogen (hydrogen gas) from the outlet for the generated hydrogen (hydrogen gas). Here, when water droplets (liquid phase moisture) are supplied to the separator 12 of the fuel cell 10 together with the hydrogen gas, the water droplets that have entered the hydrogen flow path 12c may become a resistance to the passage of the hydrogen gas, making it difficult to pass a sufficient amount of hydrogen to react with the air (oxygen). For this reason, in the fuel cell unit 1 of this embodiment, a gas-liquid separation tank 23b is disposed between the hydrogen generating device 21 and the fuel cell 10 (separator 12), and after the water (liquid phase moisture) contained in the hydrogen gas discharged from the hydrogen generating device 21 is separated in the gas-liquid separation tank 23b (after the liquid phase moisture is removed), the hydrogen gas from which the moisture has been removed is supplied to the separator 12 via the pipe 4f. As a result, in the fuel cell unit 1 of this embodiment, it is possible to suitably prevent a large amount of water droplets from entering the hydrogen flow path 12c.

[0044] Furthermore, the fuel cell unit 1 of this embodiment employs a configuration in which oxygen generated by electrolysis in the hydrogen generation device 21 is effectively utilized as part of the "first gas (oxidant)" for power generation in the fuel cell 10. In this case, in this type of hydrogen generation device, a portion of the water (water that was not electrolyzed) used as a raw material for hydrogen generation is discharged together with the oxygen generated by electrolysis. Here, when water droplets (liquid phase moisture) are supplied to the separator 11 of the fuel cell 10 together with oxygen, the water droplets that have entered the air flow passage 11c may become a resistance to the passage of oxygen (air), making it difficult to pass a sufficient amount of oxygen (air) to react with hydrogen (hydrogen gas).

[0045] For this reason, in the fuel cell unit 1 of this embodiment, a gas-liquid separation tank 23a is provided at the oxygen outlet of the hydrogen generator 21 via a pipe 4h, oxygen discharged from the hydrogen generator 21 is allowed to flow into the gas-liquid separation tank 23a, water (liquid-phase moisture) contained in the oxygen is separated in the gas-liquid separation tank 23a (after removing the liquid-phase moisture), and the oxygen from which moisture has been removed is allowed to flow into the pipe 4a via the pipe 4i. As a result, when the pump 2 starts pumping air as described below, oxygen generated by electrolysis in the hydrogen generator 21 is supplied to the separator 11 as a "first gas (oxidizer)" together with air sucked from one end of the pipe 4a, so that a "first gas" with a sufficiently high oxygen concentration is supplied to the fuel cell 10 (separator 11), and oxygen containing a large amount of moisture is preferably prevented from entering the air flow path 11c together with the atmosphere (air).

[0046] The control unit 6 also controls the pump 2 to start pumping air. In response to this, the pump 2 pumps a mixture of air sucked from one end of the pipe 4a and oxygen flowing into the pipe 4a via the pipe 4i (hereinafter, this mixture is also simply referred to as "air") to the fuel cell 10 (separator 11) via the pipe 4b.

[0047] At this time, air pumped by the pump 2 is passed through the air flow passage 11c from the pipe connection portion 11a toward the pipe connection portion 11b, and then flows into the gas-liquid separation tank 22 via the pipe 4c. Also, hydrogen gas generated in the hydrogen generation device 21 and from which liquid-phase moisture has been removed in the gas-liquid separation tank 23b is supplied to the separator 12 via the pipe 4f, passed through the hydrogen flow passage 12c from the pipe connection portion 12a toward the pipe connection portion 12b, and then flows into the post-treatment device 3 via the pipe 4g. As a result, in the fuel cell 10, the air (oxygen) passed through the air flow passage 11c of the separator 11 and the hydrogen gas (hydrogen) passed through the hydrogen flow passage 12c of the separator 12 are reacted via the MEA 13 to generate electric power.

[0048] In this case, as described above, when power generation is being performed in the fuel cell 10, water is generated in the air flow path 11c (cathode electrode side of the MEA 13) of the separator 11 due to a reaction between oxygen and hydrogen. At this time, the water generated in the air flow path 11c is discharged from the pipe connection part 11b to the pipe 4c together with the air passed through the air flow path 11c, and is guided to the gas-liquid separation tank 22. As a result, the air from which water droplets (liquid phase moisture) have been separated (the water droplets have been removed) in the gas-liquid separation tank 22 is released into the atmosphere via the pipe 4d, and the water separated from the air is collected at the bottom of the gas-liquid separation tank 22.

[0049] At this time, in the fuel cell unit 1 of this example, as described above, the ion exchange treatment device 25 is connected via the pipe 5a to the vicinity of the bottom of the gas-liquid separation tank 22 (the portion where the separated water is collected). Also, in the fuel cell unit 1 of this example, the air pressurized by the pump 2 is passed through the air flow path 11c of the separator 11 and is pressurized and fed to the gas-liquid separation tank 22 via the pipe 4c, so that the inside of the gas-liquid separation tank 22 is pressurized. Therefore, the water separated from the air in the gas-liquid separation tank 22 is discharged from the gas-liquid separation tank 22 to the pipe 5a by the force of the air pressurized into the gas-liquid separation tank 22, and is pressurized and fed to the ion exchange treatment device 25 without using a power source such as a liquid feed pump.

[0050] In addition, the water pumped to the ion exchange treatment device 25 is passed through an anion exchange resin filter to remove SO 4 2- After removing sulfuric acid ions (sulfate ions), the water is supplied to the hydrogen generation device 21 as a raw material for hydrogen generation via the pipe 5d. In this case, as described above, the water generated in the fuel cell 10 (in the air flow path 11c) and separated in the gas-liquid separation tank 22 is acidic with a pH of about 2, although it does not contain impurities such as organic matter. Therefore, if this water is used as it is as a raw material for hydrogen generation, it may cause deterioration of metal parts and pipes in the device.

[0051] Therefore, in the fuel cell unit 1 of this embodiment, a configuration is adopted in which the water separated in the gas-liquid separation tank 22 is ion-exchanged in the ion exchange treatment device 25 prior to being supplied as a raw material to the hydrogen generation device 21, thereby treating the water to a pH range from a weak acidity of about pH 6.5 to a neutral pH of 7.0. This allows the water generated in the fuel cell 10 (inside the piping connection part 11a) to be supplied as a raw material to the hydrogen generation device 21 without causing deterioration of metal parts and piping within the device, and hydrogen is continuously generated in the hydrogen generation device 21.

[0052] As described above, in the fuel cell unit 1 of this embodiment, a small amount of water (water droplets) is discharged from the hydrogen generator 21 together with the hydrogen (hydrogen gas) produced in the hydrogen generator 21 and separated from the hydrogen in the gas-liquid separation tank 23b.

[0053] In this case, the amount of water separated in the gas-liquid separation tank 23b (water discharged together with hydrogen from the hydrogen generation device 21) discharged per unit time is smaller than the amount of water discharged from the fuel cell 10 (separator 11). Also, in the fuel cell unit 1 of this example, as described below, a configuration is adopted in which water is pressure-fed from the gas-liquid separation tank 23b to the ion exchange treatment device 25 by utilizing the discharge pressure of hydrogen (hydrogen gas) from the hydrogen generation device 21, but while water is being pressure-fed, the amount of hydrogen supplied from the gas-liquid separation tank 23b to the fuel cell 10 (separator 12) decreases slightly, which may reduce the amount of hydrogen gas supplied to the fuel cell 10 and result in a decrease in power generation efficiency.

[0054] Therefore, in the fuel cell unit 1 of this example, a configuration is adopted in which, when two conditions are met: a specified amount (a predefined upper limit value) of water is stored in the gas-liquid separation tank 23b, and the amount of hydrogen gas to be supplied to the fuel cell 10 (separator 12) is below a specified amount (a state in which the amount of hydrogen gas required for power generation is small: for example, when power generation in the fuel cell 10 is stopped), the control unit 6 controls the switching valve 24b to pressure-transfer the water in the gas-liquid separation tank 23b toward the hydrogen generation device 21.

[0055] At this time, the water stored in the gas-liquid separation tank 23b is forced to flow into the pipe 5a via the pipe 5c by the discharge pressure of the hydrogen gas from the hydrogen generation device 21, and is supplied to the ion exchange treatment device 25. This water is passed through an ion exchange resin filter in the ion exchange treatment device 25, and then supplied to the hydrogen generation device 21 as a raw material. As a result, in addition to the water generated in the fuel cell 10 during power generation, the water discharged from the hydrogen generation device 21 together with the hydrogen gas is used as part of the raw material for generating hydrogen gas in the hydrogen generation device 21.

[0056] Furthermore, in the fuel cell unit 1 of this embodiment, when the amount of water stored in the gas-liquid separation tank 23b reaches a specified amount (a predefined lower limit), the control unit 6 controls the switching valve 24b to stop the inflow from the pipe 5c to the pipe 5a, thereby stopping the pressure-feeding of water from the gas-liquid separation tank 23b to the ion exchange treatment device 25. This suitably prevents hydrogen gas from being pressure-feeded from the gas-liquid separation tank 23b to the ion exchange treatment device 25 or the hydrogen generation device 21 via the pipes 5c and 5a.

[0057] As described above, in the fuel cell unit 1 of this embodiment, water (water droplets) is discharged from the hydrogen generation device 21 together with oxygen generated by hydrogen generation (electrolysis) in the hydrogen generation device 21, and is separated from the oxygen in the gas-liquid separation tank 23a. In this case, the fuel cell unit 1 of this embodiment employs a configuration in which the exhaust pressure of oxygen from the hydrogen generation device 21 is used to pressure-feed water from the gas-liquid separation tank 23a to the ion exchange treatment device 25, as will be described later.

[0058] Here, since the amount of water discharged per unit time together with oxygen in the hydrogen generation device 21 is relatively large, if this water is constantly allowed to flow into the pipe 5a, the flow of water from the gas-liquid separation tank 23a toward the ion exchange treatment device 25 may hinder the pressure-feeding of water from the gas-liquid separation tank 22 to the hydrogen generation device 21 (ion exchange treatment device 25). Therefore, in the fuel cell unit 1 of this example, a configuration is adopted in which, when the condition that a specified amount (a predefined upper limit value) of water is stored in the gas-liquid separation tank 23a is satisfied, the control unit 6 controls the switching valve 24a to pressure-feed the water in the gas-liquid separation tank 23a toward the hydrogen generation device 21.

[0059] At this time, the water stored in the gas-liquid separation tank 23a is forced to flow into the pipe 5a via the pipe 5b by the exhaust pressure of oxygen from the hydrogen generation device 21, and is supplied to the ion exchange treatment device 25. This water is passed through an ion exchange resin filter in the ion exchange treatment device 25, and then supplied to the hydrogen generation device 21 as a raw material. As a result, in addition to the water generated in the fuel cell 10 during power generation and the water discharged from the hydrogen generation device 21 together with hydrogen gas, the water discharged from the hydrogen generation device 21 together with oxygen is used as part of the raw material for generating hydrogen gas in the hydrogen generation device 21.

[0060] Furthermore, in the fuel cell unit 1 of this embodiment, when the amount of water stored in the gas-liquid separation tank 23b reaches a specified amount (a predefined lower limit), the control unit 6 controls the switching valve 24b to stop the inflow from the pipe 5c to the pipe 5a, thereby stopping the pressure-feeding of water from the gas-liquid separation tank 23b to the ion exchange treatment device 25. This suitably prevents hydrogen gas from being pressure-feeded from the gas-liquid separation tank 23b to the ion exchange treatment device 25 or the hydrogen generation device 21 via the pipes 5c and 5a.

[0061] In addition, when adopting a configuration in which it is determined that the condition "the amount of hydrogen gas to be supplied to the fuel cell 10 is below a specified amount" among the above conditions is met "when power generation in the fuel cell 10 is stopped," as an example, a battery capable of storing surplus power when the fuel cell 10 is generating power can be installed, and the power stored in this battery can be used to operate the hydrogen generation device 21, making it possible to pressure-feed water from the gas-liquid separation tanks 23a, 23b to the ion exchange treatment device 25 even when power generation is not being generated in the fuel cell 10.

[0062] Thus, this hydrogen supply system 20 comprises a hydrogen generation device 21 that electrolyzes raw material water to generate hydrogen and produce a second gas (hydrogen gas in this example), a gas-liquid separation tank 22 that separates and recovers water contained in the exhaust gas discharged from separator 11 of fuel cell 10, and an ion exchange treatment device 25 that performs ion exchange treatment on the water recovered by gas-liquid separation tank 22, and is configured so that water discharged from separator 11 together with exhaust gas due to power generation in fuel cell 10 can be ion exchanged by ion exchange treatment device 25 and supplied as a raw material to hydrogen generation device 21. Furthermore, this fuel cell unit 1 comprises the above-mentioned hydrogen supply system 20, fuel cell 10, and pump 2.

[0063] Therefore, according to this hydrogen supply system 20 and fuel cell unit 1, unlike a configuration in which water (pure water) used as a raw material in an electrolysis device that generates hydrogen is generated by an electrical regeneration type pure water generation device, the water discharged from the fuel cell 10 (separator 11) during power generation is used as a raw material for generating hydrogen in the hydrogen generation device 21, and since no electricity is required to generate the raw water, the cost of generating hydrogen can be significantly reduced, and as a result, the cost of generating electricity by the fuel cell unit 1 using the generated hydrogen can be significantly reduced.

[0064] The hydrogen supply system 20 also includes a gas-liquid separation tank 23a that separates water discharged from the hydrogen generation device 21 together with oxygen generated by electrolysis from the oxygen and recovers the water, and is configured to subject the water recovered in the gas-liquid separation tank 23a to ion exchange treatment by an ion exchange treatment device 25 and supply it as a raw material to the hydrogen generation device 21. Therefore, with the hydrogen supply system 20 and the fuel cell unit 1, water droplets (liquid water) discharged from the hydrogen generation device 21 together with oxygen generated by electrolysis when generating hydrogen (hydrogen gas) in the hydrogen generation device 21 can be used as a raw material in the hydrogen generation device 21, thereby ensuring a sufficient amount of water necessary for generating hydrogen.

[0065] Moreover, the hydrogen supply system 20 is configured to be able to supply the oxygen separated in the gas-liquid separation tank 23a to the separator 11 in the fuel cell 10. Therefore, compared to a configuration in which only the atmosphere (air) is supplied to the separator 11 of the fuel cell 10 as the "first gas containing an oxidizer," the hydrogen supply system 20 and the fuel cell unit 1 supply the oxygen generated in the hydrogen generator 21 (in this example, a mixture of this oxygen and the atmosphere (air)) to the separator 11, and the "first gas" having a sufficiently high oxygen concentration is reacted with hydrogen (hydrogen gas), thereby enabling efficient power generation. Also, compared to a configuration in which the oxygen generated in the hydrogen generator 21 is simply released into the atmosphere, for example, it is possible to preferably avoid a situation in which an unintended oxidation reaction (fire, etc.) occurs.

[0066] The hydrogen supply system 20 is also provided with a gas-liquid separation tank 23b that separates and recovers water contained in the second gas generated by the hydrogen generation device 21, and is configured to subject the water recovered by the gas-liquid separation tank 23b to ion exchange treatment by an ion exchange treatment device 25 and supply it as a raw material to the hydrogen generation device 21. Therefore, with the hydrogen supply system 20 and the fuel cell unit 1, not only can a sufficient amount of water be used as a raw material in the hydrogen generation device 21 be secured, but also a large amount of water droplets (liquid water) discharged from the hydrogen generation device 21 together with the hydrogen gas generated in the hydrogen generation device 21 can be prevented from being supplied to the fuel cell 10 (separator 12) and causing an excessive increase in the passage resistance of the hydrogen gas in the separator 12 (hydrogen flow path 12c), thereby enabling the fuel cell 10 to generate electricity appropriately.

[0067] The configuration of the "fuel cell unit" is not limited to the example of the configuration of the fuel cell unit 1 described above.

[0068] For example, the above description has been given of an example of a configuration in which the "gas supply device" is a pressure-type pump 2 that pressure-feeds air into the air flow path 11c of the separator 11, but the configuration may also include a suction-type "gas supply device." Specifically, the fuel cell unit 1A shown in Fig. 2 is another example of a "fuel cell unit," and includes a pump 2a, which is another example of a "gas supply device that supplies a first gas to a first separator," instead of the pump 2 in the fuel cell unit 1 described above.

[0069] In addition, in this fuel cell unit 1A, the basic configuration is the same as that of the fuel cell unit 1, except that instead of the pipe 4b in the fuel cell unit 1, a pipe 4a is connected to the fuel cell 10 (11a of the separator 11), and instead of the pipe 4c, pipes 4c1 and 4c2 are provided and a pump 2a is connected to them. Therefore, components having the same functions as those in the above-mentioned fuel cell unit 1 are given the same reference numerals and duplicated explanations are omitted. In addition, the principle of hydrogen (hydrogen gas) generation by the hydrogen supply system 20 is the same as that of the hydrogen supply system 20 in the fuel cell unit 1, so a detailed explanation is omitted.

[0070] In this fuel cell unit 1A, an intake port of pump 2a is connected to pipe connection part 11b of separator 11 via pipe 4c1, and an exhaust port of pump 2a is connected to gas-liquid separation tank 22 via pipe 4c2. Also, in this fuel cell unit 1A, a configuration is adopted in which pump 2a sucks air from within air flow path 11c, thereby supplying new air from pipe 4a connected to pipe connection part 11a into air flow path 11c, and air passed through air flow path 11c (air containing water produced by reaction with hydrogen) is guided to gas-liquid separation tank 22 via pipe 4c2.

[0071] As a result, in this fuel cell unit 1A, similarly to the fuel cell unit 1 described above, the water discharged together with the air from the separator 11 and separated in the gas-liquid separation tank 22 is guided from the gas-liquid separation tank 22 through the pipe 5a by the air pumping force of the pump 2a to the ion exchange treatment device 25, and after ion exchange treatment in the ion exchange treatment device 25, is supplied as a raw material to the hydrogen generation device 21. Therefore, with this fuel cell unit 1A, the same effects as those of the fuel cell unit 1 described above can be achieved.

[0072] In addition, the configuration in which the water pumped from the gas-liquid separation tank 22, the water pumped from the gas-liquid separation tank 23a, and the water pumped from the gas-liquid separation tank 23b are all ion-exchanged by one ion-exchange treatment device 25 has been described as an example, but a plurality of "treatment devices" may be arranged so that the water pumped from each of the gas-liquid separation tanks 22, 23a, and 23b is individually ion-exchanged. In addition, the example in which the ion-exchange treatment device 25 is provided with a configuration in which water is ion-exchanged by passing through an anion-exchange resin filter has been described as an example, but instead of such a configuration, it is also possible to provide a "treatment device" that is provided with a configuration in which water is ion-exchanged electrochemically. In addition, the "first recovery device", "second recovery device", and "third recovery device" are not limited to a configuration in which a "separation tank" such as the gas-liquid separation tanks 22, 23a, and 23b is provided, and these "recovery devices" may also be provided with an "adsorption filter" capable of adsorbing moisture.

[0073] In addition, although an example has been described in which the water discharged together with oxygen from the hydrogen generation apparatus 21 (water separated from oxygen in the gas-liquid separation tank 23a) can be used as part of the "raw material", it is also possible to adopt a configuration in which this water is not used as the "raw material". Also, although an example has been described in which the water discharged together with hydrogen gas from the hydrogen generation apparatus 21 (water separated from hydrogen gas in the gas-liquid separation tank 23b) can be used as part of the "raw material", it is also possible to adopt a configuration in which this water is not used as the "raw material". [Explanation of symbols]

[0074] 1,1A Fuel Cell Unit 2,2a Pump 3. Aftertreatment Device 4a~4i,4c1,4c2,5a~5d Piping 6 Control section 10 Fuel Cell 11,12 Separator 11a, 11b, 12a, 12b Piping connection parts 11c Air passage 12c Hydrogen flow path 13 MEA 20 Hydrogen Supply System 21 Hydrogen generator 22,23a,23b Gas-liquid separation tank 24a, 24b Switching valve 25 Ion exchange treatment equipment

Claims

1. A fuel supply system configured to be capable of supplying the second gas as fuel to the second separator of a fuel cell main body, the fuel cell main body being configured to generate electricity by reacting the first gas with the second gas via the membrane electrode assembly, the fuel cell main body being configured in such a manner that a plurality of flat plate-like laminated objects including at least a first separator through which a first gas containing an oxidant is passed, a second separator through which a second gas containing hydrogen is passed, and a membrane electrode assembly disposed between the first separator and the second separator are laminated and integrated together, the second gas being supplied as fuel to the second separator of the fuel cell main body being configured in such a manner that the first gas and the second gas are reacted via the membrane electrode assembly, A generator that electrolyzes raw water to generate the hydrogen and generate the second gas; a first recovery device that separates and recovers water contained in the exhaust gas discharged from the first separator from the exhaust gas; a treatment device for performing ion exchange treatment on the water recovered by the first recovery device, a fuel supply system configured to subject water discharged from the first separator together with the exhaust gas due to power generation in the fuel cell body to ion exchange treatment by the treatment device and supply the water to the generation device as the raw material;

2. a second recovery device that separates water discharged from the generation device together with the oxygen generated by electrolysis from the oxygen and recovers the water; 2. The fuel supply system according to claim 1, wherein the water recovered by the second recovery device is ion-exchanged by the treatment device and can be supplied to the production device as the raw material.

3. 3. The fuel supply system according to claim 2, wherein the oxygen separated in the second recovery device is capable of being supplied to the first separator in the fuel cell main body.

4. a third recovery device that separates and recovers water contained in the second gas generated by the generation device from the second gas; 2. The fuel supply system according to claim 1, wherein the water recovered by the third recovery device is ion-exchanged by the treatment device and can be supplied to the production device as the raw material.

5. A fuel supply system according to any one of claims 1 to 4; the fuel cell main body being formed by stacking and integrating a plurality of flat plate-shaped laminated objects each including at least the first separator, the second separator, and the membrane electrode assembly; a gas supply device that supplies the first gas to the first separator;

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