Hydrogen production plant and hydrogen production method

Abstract

The purpose of the present invention is to improve the safety of a hydrogen production plant. This hydrogen production plant (1) comprises: a solid oxide electrolysis cell (SOEC) (10) which produces a hydrogen-containing gas; and a discharge stack (30) into which the hydrogen-containing gas produced by the SOEC (10) is introduced and which discharges the introduced hydrogen-containing gas to air. The discharge stack (30) has a spray unit (32) which supplies, to the hydrogen-containing gas introduced therein, cooling water for cooling the hydrogen-containing gas.

Description

Hydrogen production plant and hydrogen production method

[0001] The present disclosure relates to a hydrogen production plant and a hydrogen production method.

[0002] In the recent trend toward carbon neutrality, hydrogen is used for various purposes, and therefore, facilities for producing hydrogen are known (for example, Patent Document 1).

[0003] Patent Document 1 describes a dehumidification device including a mixed gas generation unit that generates a mixed gas of oxyhydrogen gas and liquefied petroleum gas, and a dehumidification unit that reduces the humidity of the mixed gas generated in the mixed gas generation unit. The mixed gas generation unit described in Patent Document 1 includes an electrolytic cell that generates oxyhydrogen gas by electrolysis, etc. The dehumidification unit also includes a gas-liquid contact vessel that removes moisture contained in the mixed gas through gas-liquid contact, and a cooler that cools the liquid that comes into contact with the mixed gas in the gas-liquid contact vessel.

[0004] JP 2014-223590 A

[0005] In hydrogen production facilities, hydrogen may be released into the atmosphere during startup, emergency shutdown, etc. For this reason, it has been considered to provide hydrogen production facilities with a release section that releases hydrogen into the atmosphere. Because hydrogen can self-ignite when heated to high temperatures, it is also necessary to improve the safety of the release section that releases hydrogen into the atmosphere. However, the dehumidifying device described in Patent Document 1 does not include a release section that releases the generated hydrogen-containing gas into the atmosphere, and Patent Document 1 does not take into consideration the safety of a device that includes a release section.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide a hydrogen production plant and a hydrogen production method that can improve safety.

[0007] In order to solve the above problems, the hydrogen production plant and hydrogen production method of the present disclosure employ the following measures: A hydrogen production plant according to one aspect of the present disclosure includes a production unit that produces a hydrogen-containing gas, and a release unit into which the hydrogen-containing gas produced in the production unit is introduced and which releases the introduced hydrogen-containing gas to the atmosphere, and the release unit has a cooling fluid supply unit that supplies a cooling fluid that cools the hydrogen-containing gas to the hydrogen-containing gas introduced into the release unit.

[0008] Furthermore, a hydrogen production method according to one aspect of the present disclosure includes a production process for producing a hydrogen-containing gas, an introduction process for introducing the hydrogen-containing gas produced in the production process into a release section, a supply process for supplying a cooling fluid to the hydrogen-containing gas introduced into the release section, and a release process for releasing the hydrogen-containing gas introduced into the release section into the atmosphere.

[0009] According to the present disclosure, the safety of a hydrogen production plant can be improved.

[0010] 1 is a schematic configuration diagram illustrating a hydrogen production plant according to an embodiment of the present disclosure; 2 is a block diagram illustrating a control device according to an embodiment of the present disclosure;

[0011] An embodiment of a hydrogen production plant and a hydrogen production method according to the present disclosure will be described below with reference to the drawings. The hydrogen production plant 1 according to this embodiment is a plant that produces hydrogen during normal operation. Furthermore, the hydrogen production plant 1 may release hydrogen-containing gas into the atmosphere during startup or emergency shutdown.

[0012] As shown in FIG. 1 , the hydrogen production plant 1 includes an SOEC device (hereinafter referred to as SOEC 10) that produces hydrogen-containing gas using a solid oxide electrolysis cell (SOEC), an instrumentation air supply unit 11 that supplies instrumentation air to the SOEC 10, a city gas supply unit 12 that supplies city gas to the SOEC 10, a hydrogen gas supply unit 13 that supplies hydrogen gas to the SOEC 10, a nitrogen gas supply unit 14 that supplies nitrogen gas to the SOEC, a makeup water supply unit 15 that supplies makeup water to an electric boiler (steam generating unit) 17, an electrolysis air supply unit 16 that supplies electrolysis air (electrolysis gas) to the SOEC 10, the electric boiler 17 that heats the makeup water to generate steam to be supplied to the SOEC 10, and a heat exchanger 18 that performs heat exchange between the electrolysis air supplied to the SOEC 10 and the electrolysis air (exhaust air) discharged from the SOEC 10.

[0013] The SOEC (production unit) 10 is supplied with high-temperature, high-pressure electrolysis gas (air, as an example in this embodiment) and high-temperature, high-pressure water vapor. The electrolysis gas and water vapor supplied to the SOEC 10 are introduced into an electrolysis chamber housing an electrolysis cell. The SOEC 10 electrolyzes water vapor using a high-temperature solid electrolyte in the electrolysis chamber to produce a hydrogen-containing gas (a mixed gas of hydrogen and water vapor) and oxygen. The generated hydrogen-containing gas is discharged to the outside via a hydrogen-containing gas pipe L4. The generated oxygen is also discharged to the outside together with exhaust air. The SOEC uses ceramics, such as yttria-stabilized zirconia, as an electrolyte and uses high-temperature water vapor as a raw material, enabling it to produce hydrogen more efficiently than other water electrolysis devices. Furthermore, co-electrolysis is also possible, in which carbon dioxide (CO) is used as a raw material and electrolytic hydrogen is used as a reducing agent to produce carbon monoxide (CO).

[0014] The instrument air supply unit 11 supplies air (instrument air) to the SOEC 10, which is used for driving a control valve (not shown) provided in the SOEC 10. The city gas supply unit 12 supplies city gas to the SOEC 10 for heating the SOEC 10 when the SOEC 10 is started up. The hydrogen gas supply unit 13 supplies hydrogen gas to the SOEC 10 for creating a reducing atmosphere in the electrolytic cell when the SOEC 10 is started up. The nitrogen gas supply unit 14 supplies nitrogen gas to the SOEC 10 for purging oxygen and air remaining in the SOEC 10 when the SOEC 10 is started up.

[0015] The hydrogen production plant 1 also includes a nitrogen pipe (first nitrogen pipe) L1 that connects the nitrogen gas supply unit 14 and the SOEC 10, a makeup water pipe L2 that connects the makeup water supply unit 15 and the electric boiler 17, and a steam pipe (first steam pipe) L3 that connects the electric boiler 17 and the SOEC 10. The nitrogen pipe L1 guides nitrogen gas supplied from the nitrogen gas supply unit 14 to the SOEC 10. The makeup water pipe L2 guides makeup water supplied from the makeup water supply unit 15 to the electric boiler 17. The steam pipe L3 guides steam generated by the electric boiler 17 to the SOEC 10. A first steam valve B1 is provided on the steam pipe L3. The first steam valve B1 is, for example, a solenoid valve.

[0016] The hydrogen production plant 1 also includes a hydrogen generation unit 20 that generates product gas (hydrogen) from the hydrogen-containing gas produced in the SOEC 10, and a release stack (release unit) 30 into which the hydrogen-containing gas produced in the SOEC 10 is introduced and which releases the introduced hydrogen-containing gas into the atmosphere.

[0017] The hydrogen production plant 1 also includes a hydrogen-containing gas pipe L4 connecting the SOEC 10 and the release stack 30, a branch nitrogen pipe (second nitrogen pipe) L5 ​​branching from the nitrogen pipe L1, a branch makeup water pipe L6 branching from the makeup water pipe L2, a branch steam pipe L7 branching from the steam pipe L3, and a branch hydrogen-containing gas pipe L8 branching from the hydrogen-containing gas pipe L4. The hydrogen-containing gas pipe L4 guides the hydrogen-containing gas produced in the SOEC 10 to the release stack 30. The branch nitrogen pipe L5 connects the nitrogen pipe L1 and the release stack 30, and guides a portion of the nitrogen gas flowing through the nitrogen pipe L1 to the release stack 30. The branch makeup water pipe L6 connects the makeup water pipe L2 and the release stack 30, and guides a portion of the makeup water flowing through the makeup water pipe L2 to the release stack 30. The branch steam pipe (second steam pipe) L7 connects the steam pipe L3 and the release stack 30, and guides a part or all of the steam flowing through the steam pipe L3 to the release stack 30. The branch hydrogen-containing gas pipe L8 guides a part or all of the hydrogen-containing gas flowing through the hydrogen-containing gas pipe L4 to the hydrogen generator 20.

[0018] The hydrogen-containing gas pipe L4 is provided with a first hydrogen-containing gas valve B2. The branch nitrogen pipe L5 is provided with a nitrogen valve B3. The branch steam pipe L7 is provided with a second steam valve B4. The branch hydrogen-containing gas pipe L8 is provided with a second hydrogen-containing gas valve B5. The first hydrogen-containing gas valve B2, the nitrogen valve B3, the second steam valve B4, and the second hydrogen-containing gas valve B5 are each, for example, a solenoid valve. The branch makeup water pipe L6 is provided with a cooling water valve (cooling fluid adjustment unit) B6. The cooling water valve B6 is, for example, a flow rate adjustment valve. The cooling water valve B6 adjusts the amount of cooling water supplied from a spray unit (cooling fluid supply unit) 32, which will be described later.

[0019] The hydrogen generation unit 20 has a cooler 21 into which hydrogen-containing gas is introduced via a branch hydrogen-containing gas pipe L8, a dehumidifier 22 into which hydrogen-containing gas discharged from the cooler 21 is introduced, and a compressor 23 into which hydrogen-containing gas discharged from the dehumidifier 22 is introduced.

[0020] The cooler 21 condenses the water vapor by cooling the hydrogen-containing gas. In this way, the cooler 21 separates hydrogen from the water vapor. The dehumidifier 22 dehumidifies the hydrogen-containing gas cooled by the cooler 21. The compressor 23 pressurizes the hydrogen-containing gas dehumidified by the dehumidifier 22. In this way, the hydrogen generation unit 20 separates the water vapor from the hydrogen-containing gas to generate the product gas (hydrogen).

[0021] The discharge stack 30 has a housing 31 that forms the outer shell, a spray section (cooling fluid supply section) 32 provided inside the housing 31, a storage section 33 provided at the bottom inside the housing 31, a sealing section 34 provided at the top inside the housing 31, and a discharge section 35 that discharges condensed water stored in the storage section 33.

[0022] The housing 31 has a space formed inside. The housing 31 has a cylindrical large-diameter portion 31a and a cylindrical small-diameter portion 31b connected to the upper part of the large-diameter portion 31a. The large-diameter portion 31a has a larger diameter than the small-diameter portion 31b. The downstream ends of the hydrogen-containing gas pipe L4 and the branch nitrogen pipe L5 are connected to the large-diameter portion 31a. A discharge opening 31c that opens toward the atmosphere is formed at the upper end of the small-diameter portion 31b. The hydrogen-containing gas introduced into the housing 31 is discharged into the atmosphere through the discharge opening 31c.

[0023] The spray unit 32 is provided inside the large diameter portion 31a and at an upper portion of the large diameter portion 31a. The spray unit 32 has, for example, a spray pipe extending horizontally and a plurality of nozzles provided on the underside of the spray pipe. The plurality of nozzles are arranged at equal intervals along the extension direction of the spray pipe. The downstream end of the branch makeup water pipe L6 is connected to the spray pipe. Make-up water is supplied to the spray pipe via the branch makeup water pipe L6 as cooling water for cooling the hydrogen-containing gas. The spray unit 32 sprays the cooling water (cooling fluid) supplied to the spray pipe downward from the plurality of nozzles. Specifically, the spray unit 32 sprays the cooling water onto the hydrogen-containing gas supplied inside the housing 31. This cools the hydrogen-containing gas. Note that any sprayed cooling water that does not evaporate drips onto the lower portion of the housing 31.

[0024] The reservoir 33 is provided in the lower part of the housing 31. The reservoir 33 stores the sprayed cooling water that has not evaporated.

[0025] The seal portion 34 utilizes the gas supplied into the emission stack 30 to suppress the inflow (backflow) of atmospheric air from the emission opening 31c.

[0026] The seal portion 34 uses the hydrogen-containing gas introduced into the release stack 30 via the hydrogen-containing gas pipe L4 as a sealing gas. That is, the hydrogen-containing gas introduced into the release stack 30 rises within the release stack 30. As a result, the hydrogen-containing gas pushes back the air (particularly oxygen) that attempts to flow into the release stack 30 from the release opening 31c. In this way, the hydrogen-containing gas is used as a sealing gas.

[0027] Furthermore, the seal portion 34 may be, for example, a so-called velocity seal. The seal portion 34 has a reduced diameter portion 34a provided inside the small diameter portion 31b. The reduced diameter portion 34a is a truncated cone-shaped member with openings at the upper and lower ends. The reduced diameter portion 34a abuts the inner circumferential surface of the small diameter portion 31b over the entire circumferential area of ​​the lower end. The reduced diameter portion 34a has a sloped sidewall so that the diameter decreases upward. The hydrogen-containing gas introduced into the release stack 30 rises within the release stack 30 and passes through the reduced diameter portion 34a from bottom to top.

[0028] In this way, the gas supplied from the SOEC 10 to the inside of the emission stack 30 is used to prevent oxygen from the atmosphere from flowing into the inside of the emission stack 30 through the emission opening 31c.

[0029] The electric boiler 17 generates steam before the start of electrolysis, such as at startup, and also during electrolysis (during normal operation). Therefore, before the start of electrolysis in the SOEC 10, steam can be used as a seal gas for the stack. When steam or hydrogen cannot be supplied to the release stack 30 or there is an insufficient supply, such as during an emergency stop of the SOEC 10 and the electric boiler 17, nitrogen supplied via the branch nitrogen pipe L5 may be used as a seal gas. When the amount of seal gas discharged from the SOEC 10 is insufficient, a portion of the steam supplied from the electric boiler 17 to the SOEC 10 may be supplied to the stack via the branch steam pipe L7. An oxygen concentration meter may be installed inside the release stack 30 to measure the oxygen concentration in the release stack 30 and monitor whether oxygen from the atmosphere is flowing into the release stack 30.

[0030] The discharge unit 35 discharges the water stored in the storage unit 33 to a drainage pit 41 provided outside the system. The discharge unit 35 has a U-shaped pipe 35a formed in a U shape. One end of the U-shaped pipe 35a is connected to the housing 31 (storage unit 33) via a horizontal pipe. The other end of the U-shaped pipe 35a is connected to the drainage pit 41 via a horizontal pipe. The inside of the U-shaped pipe 35a is filled with liquid (raw water). This seals the discharge stack 30 so that air does not flow into the discharge stack 30 via the U-shaped pipe 35a, or hydrogen in the discharge stack 30 does not flow out via the discharge unit 35 to the outside.

[0031] Furthermore, because there is a possibility that raw water may evaporate within the U-shaped pipe 35a, a constant amount of raw water is constantly supplied to the U-shaped pipe 35a from the raw water supply unit 40. This prevents deterioration of sealing performance due to an excessive decrease in the raw water filled in the U-shaped pipe 35a. Note that a level meter for detecting the liquid level of the raw water inside the U-shaped pipe 35a may be provided in the U-shaped pipe 35a to monitor the liquid level.

[0032] 2, the hydrogen production plant 1 is also provided with a thermometer (temperature detection unit) 51 that measures the temperature of the hydrogen-containing gas after it has been cooled by the spray unit 32, and a level meter (level detection unit) 52 that detects the liquid level of the water stored in the storage unit 33. Also, as shown in Fig. 2, the hydrogen production plant 1 is also provided with a control unit 50. The control unit 50 controls the opening degree of each valve provided in the hydrogen production plant 1. The control unit 50 also acquires information from the thermometer 51 and the level meter 52.

[0033] The control unit 50 includes, for example, a CPU (Central Processing Unit), a main memory, and a secondary storage. The control unit 50 may also include a communication unit for transmitting and receiving information to and from other devices. The main memory is composed of, for example, a writable memory such as a cache memory or a RAM (Random Access Memory), and is used as a working area for reading the CPU's execution program and writing data processed by the execution program. The secondary storage is a non-transitory computer-readable storage medium. The secondary storage is, for example, a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, or a semiconductor memory. For example, a series of processes for realizing various functions is stored in the form of a program in a secondary storage device, and the CPU reads this program into the main storage device and executes information processing and arithmetic operations to realize various functions. Note that the program may be pre-installed in the secondary storage device, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0034] The control unit 50 controls the opening degree of the cooling water valve B6 based on the temperature of the hydrogen-containing gas detected by the thermometer 51. That is, the control unit 50 adjusts the amount of cooling water supplied from the spray unit 32 based on the temperature of the hydrogen-containing gas detected by the thermometer 51. Specifically, the control unit 50 may increase the opening degree of the cooling water valve B6 to increase the amount of cooling water when the temperature of the hydrogen-containing gas detected by the thermometer 51 is equal to or higher than a predetermined temperature (e.g., about 400°C), and may decrease the opening degree of the cooling water valve B6 to decrease the amount of cooling water when the temperature of the hydrogen-containing gas detected by the thermometer 51 is lower than the predetermined temperature.

[0035] Furthermore, the control unit 50 may control the opening degree of the cooling water valve B6 based on the liquid level detected by the level meter 52. That is, the control unit 50 may adjust the amount of cooling water supplied from the spray unit 32 based on the liquid level detected by the level meter 52. Specifically, the control unit 50 may control the cooling water valve B6 to increase the amount of cooling water when the liquid level detected by the level meter 52 is lower than a predetermined level, and may control the cooling water valve B6 to decrease the amount of cooling water when the liquid level detected by the level meter 52 is higher than the predetermined level.

[0036] Methods for adjusting the amount of cooling water performed by the control unit 50 include adjusting the flow rate of cooling water supplied from the spray unit 32 using a control valve (not shown), and switching between flowing (on) and stopping (off) water to the spray unit 32 by opening and closing the cooling water valve B6.

[0037] Next, the behavior of the hydrogen production plant 1 during normal operation, startup, and emergency shutdown will be described.

[0038] [During Normal Operation] During normal operation, the hydrogen production plant 1 generates hydrogen as a product gas in the hydrogen generation unit 20. That is, the hydrogen production plant 1 supplies the hydrogen-containing gas generated in the SOEC 10 to the hydrogen generation unit 20 via the branch hydrogen-containing gas pipe L8. At this time, the control unit 50 fully closes the first hydrogen-containing gas valve B2 and fully opens the second hydrogen-containing gas valve B5. The control unit 50 also fully opens the first steam valve B1 and fully closes the nitrogen valve B3 and second steam valve B4.

[0039] [During Startup or Emergency Shutdown] During startup or emergency shutdown, the hydrogen production plant 1 releases hydrogen-containing gas into the atmosphere. That is, the hydrogen production plant 1 supplies the hydrogen-containing gas generated in the SOEC 10 to the release stack 30 via the hydrogen-containing gas pipe L4. At this time, the control unit 50 fully opens the first hydrogen-containing gas valve B2 and fully closes the second hydrogen-containing gas valve B5. The control unit 50 also opens the second steam valve B4. Note that if an accident occurs in the hydrogen production plant 1 and cooling water is not supplied to the spray unit 32 of the release stack 30, or if sealing steam is not supplied to the release stack 30 or is insufficient, the control unit 50 may fully open the nitrogen valve B3. With the nitrogen valve B3 fully open, nitrogen gas may be supplied to the release stack 30, and the nitrogen gas may be used as a substitute for cooling water or sealing steam.

[0040] During startup, water vapor is introduced after the temperature in the electrolysis chamber of the SOEC 10 reaches a certain value or higher, and electrolysis is initiated by applying an electrolysis voltage to generate hydrogen. Once operation of the device has stabilized, the system switches over to directing the hydrogen-containing gas to the product gas system (hydrogen generation unit 20). Emergency shutdowns include, for example, when the SOEC 10 is interlocked or when the equipment that supplies the product gas breaks down. In such cases, the system switches over to directing the hydrogen-containing gas to the release stack 30.

[0041] According to this embodiment, the following advantageous effects are achieved. In this embodiment, the release stack 30 has a spray unit 32 that supplies cooling water to the hydrogen-containing gas introduced therein, thereby cooling the hydrogen-containing gas supplied to the release stack 30. This makes it possible to prevent spontaneous ignition of the hydrogen-containing gas when it is released into the atmosphere. This improves the safety of the hydrogen production plant 1.

[0042] In this embodiment, the release stack 30 has a seal portion 34 that prevents atmospheric air from entering through the release opening 31c. This prevents atmospheric air from passing through the release opening 31c and entering the inside of the release stack 30. This makes it possible to avoid combustion of the hydrogen-containing gas inside the release stack 30. This improves the safety of the hydrogen production plant 1.

[0043] In addition, in this embodiment, the inflow of atmospheric air is suppressed by using steam generated by the electric boiler 17. This reduces the number of parts compared to a case where a separate device is provided to supply gas to the discharge stack 30 to suppress the inflow of atmospheric air. This reduces costs and also saves space.

[0044] Furthermore, this embodiment includes a control unit 50 that controls the cooling water valve B6 based on the temperature of the hydrogen-containing gas detected by the thermometer 51. This makes it possible to adjust the amount of cooling water based on the temperature of the hydrogen-containing gas after it has been cooled by the spray unit 32. Therefore, when the control unit 50 controls the cooling water valve B6 so that the temperature of the hydrogen-containing gas is within a predetermined temperature range, the temperature of the hydrogen-containing gas can be kept within the predetermined temperature range. This makes it possible to more effectively prevent spontaneous ignition of the hydrogen-containing gas when it is released into the atmosphere. This improves the safety of the hydrogen production plant 1.

[0045] This embodiment also includes a control unit 50 that controls the cooling water valve B6 based on the liquid level detected by the level meter 52. This makes it possible to adjust the amount of cooling water based on the liquid level of the water stored in the storage unit 33. Because the liquid level changes depending on the amount of stored water, the amount of stored water can be estimated by detecting the liquid level.

[0046] Furthermore, in this embodiment, a branch nitrogen pipe L5 is provided that guides nitrogen gas from the nitrogen gas supply unit 14 to the release stack 30. This allows nitrogen gas to be supplied to the release stack 30. Therefore, for example, if the spray unit 32 is stopped in an emergency and cooling water cannot be supplied to the hydrogen-containing gas, nitrogen gas can be supplied to the release stack 30 to cool the hydrogen-containing gas with the nitrogen gas. Therefore, even if the spray unit 32 is stopped in an emergency, the hydrogen-containing gas can be cooled, and spontaneous ignition of the hydrogen-containing gas when it is released into the atmosphere can be suppressed. This improves the safety of the hydrogen production plant 1.

[0047] In addition, in this embodiment, nitrogen is supplied to the discharge stack 30 by the nitrogen gas supply unit 14 that supplies nitrogen to the SOEC 10. That is, nitrogen is supplied to both the SOEC 10 and the discharge stack 30 from the same device (nitrogen gas supply unit 14). This allows the number of parts to be reduced compared to when a separate device is provided to supply nitrogen to the discharge stack 30. Therefore, costs can be reduced. Also, space can be saved.

[0048] In this embodiment, the discharge section 35 has a U-shape and includes a U-shaped pipe 35a filled with a liquid. As a result, the liquid filled inside the discharge section 35 seals the inside and outside of the release stack 30. This prevents air from flowing into the release stack 30 through the discharge section 35. This prevents combustion of the hydrogen-containing gas inside the release stack 30. This also prevents the hydrogen-containing gas in the release stack 30 from leaking into the atmosphere and burning. This improves the safety of the hydrogen production plant 1.

[0049] The present disclosure is not limited to the above-described embodiment, and appropriate modifications are possible within the scope of the present disclosure. For example, in the above-described embodiment, an example in which a velocity seal is provided as the sealing portion 34 in the discharge stack 30 is described, but the present disclosure is not limited to this. For example, a molecular seal may be provided as the sealing portion 34 in the discharge stack 30. Furthermore, if a sufficient seal can be ensured with the gas supplied into the discharge stack 30, it is not necessary to provide a sealing mechanism such as the reduced diameter portion 34a (velocity seal).

[0050] In the above embodiment, the SOEC 10 is used as a device for producing a hydrogen-containing gas, but the present disclosure is not limited thereto. The device for producing a hydrogen-containing gas may be a device that electrolyzes water at high temperatures.

[0051] The hydrogen production plant and the hydrogen production method described in the above-described embodiments can be understood, for example, as follows: A hydrogen production plant according to a first aspect of the present disclosure includes a production unit (10) that produces a hydrogen-containing gas, and a release unit (30) into which the hydrogen-containing gas produced in the production unit (10) is introduced and which releases the introduced hydrogen-containing gas to the atmosphere, and the release unit (30) has a cooling fluid supply unit (32) that supplies a cooling fluid that cools the hydrogen-containing gas to the hydrogen-containing gas introduced therein.

[0052] In the above configuration, the release unit has a cooling fluid supply unit that supplies a cooling fluid to the hydrogen-containing gas introduced therein, cooling the hydrogen-containing gas. This allows the hydrogen-containing gas supplied to the release unit to be cooled. Therefore, spontaneous ignition of the hydrogen-containing gas when released into the atmosphere can be suppressed. This improves the safety of the hydrogen production plant.

[0053] Furthermore, a hydrogen production plant according to a second aspect of the present disclosure is the same as that of the first aspect, except that it includes a steam generation unit (17) that generates steam to be supplied to the production unit (10), a first steam pipe (L3) that guides the steam generated in the steam generation unit (17) to the production unit (10), and a second steam pipe (L7) that guides the steam generated in the steam generation unit (17) to the release unit (30), and the release unit (30) has a release opening (31c) that opens toward the atmosphere and a seal unit that uses steam supplied via the second steam pipe (L7) to suppress the inflow of atmosphere from the release opening (31c).

[0054] In the above configuration, the release section has a seal section that suppresses the inflow of atmospheric air, particularly oxygen, from the release opening. This makes it possible to prevent atmospheric air, particularly oxygen, from passing through the release opening and entering the inside of the release section. Therefore, combustion of the hydrogen-containing gas inside the release section can be avoided. This improves the safety of the hydrogen production plant. Furthermore, in the above configuration, the steam generated in the steam generating section is used to suppress the inflow of atmospheric air, particularly oxygen. This reduces the number of parts compared to when a separate device is provided to supply a gas that suppresses the inflow of atmospheric air, particularly oxygen, to the release section. This reduces costs. Furthermore, space can be saved.

[0055] Furthermore, in a hydrogen production plant according to a third aspect of the present disclosure, in the above-mentioned first or second aspect, the release unit (30) has a cooling fluid adjustment unit (B6) that adjusts the amount of cooling fluid supplied from the cooling fluid supply unit (32) and a temperature detection unit (51) that detects the temperature of the hydrogen-containing gas after cooling by the cooling fluid, and is equipped with a control unit (50) that controls the cooling fluid adjustment unit (B6) based on the temperature of the hydrogen-containing gas detected by the temperature detection unit (51).

[0056] The above configuration includes a control unit that controls the cooling fluid adjustment unit based on the temperature of the hydrogen-containing gas detected by the temperature detection unit. This makes it possible to adjust the amount of cooling fluid based on the temperature of the hydrogen-containing gas after it has been cooled by the cooling fluid supply unit. Therefore, when the control unit controls the cooling fluid adjustment unit so that the temperature of the hydrogen-containing gas is within a predetermined temperature range, the temperature of the hydrogen-containing gas can be kept within the predetermined temperature range. This makes it possible to more effectively prevent spontaneous ignition of the hydrogen-containing gas when it is released into the atmosphere. This improves the safety of the hydrogen production plant.

[0057] The control unit may control the cooling fluid adjustment unit to increase the amount of cooling fluid when the temperature of the hydrogen-containing gas detected by the temperature detection unit is higher than a predetermined temperature range, and may control the cooling fluid adjustment unit to decrease the amount of cooling fluid when the temperature of the hydrogen-containing gas detected by the temperature detection unit is lower than the predetermined temperature range. Methods for adjusting the amount of cooling fluid performed by the control unit include a method of adjusting the amount of cooling fluid supplied from the cooling fluid supply unit and a method of switching the cooling fluid supply unit on and off.

[0058] Furthermore, in the hydrogen production plant according to a fourth aspect of the present disclosure, in the first or second aspect, the release unit (30) has a cooling fluid adjustment unit (B6) that adjusts the amount of cooling fluid supplied from the cooling fluid supply unit (32), a storage unit (33) that stores condensed water generated by condensation of the hydrogen-containing gas, and a level detection unit (52) that detects the liquid level of the condensed water stored in the storage unit (33), and is equipped with a control unit (50) that controls the cooling fluid adjustment unit (B6) based on the liquid level detected by the level detection unit (52).

[0059] In the above configuration, a control unit is provided that controls the cooling fluid adjustment unit based on the liquid level detected by the level detection unit. This allows the amount of cooling fluid to be adjusted based on the liquid level of the water stored in the storage unit. Since the liquid level changes depending on the amount of stored water, the amount of stored water can be estimated by detecting the liquid level.

[0060] In addition, the control unit may control the cooling fluid adjustment unit to increase the amount of cooling fluid when the liquid level detected by the level detection unit is lower than a predetermined level, and may control the cooling fluid adjustment unit to decrease the amount of cooling fluid when the liquid level detected by the level detection unit is higher than the predetermined level.

[0061] Furthermore, a hydrogen production plant according to a fifth aspect of the present disclosure is any one of the first to fourth aspects, and further includes a first nitrogen pipe (L1) that guides nitrogen gas from a nitrogen supply unit (14) to the production unit (10), and a second nitrogen pipe (L5) that guides nitrogen gas from the nitrogen supply unit (14) to the release unit (30).

[0062] The above configuration includes a second nitrogen pipe that guides nitrogen gas from the nitrogen supply unit to the release unit. This allows nitrogen gas to be supplied to the release unit. Therefore, for example, if the cooling fluid supply unit is stopped in an emergency and cooling fluid cannot be supplied to the hydrogen-containing gas, nitrogen gas can be supplied to the release unit to cool the hydrogen-containing gas with the nitrogen gas. Therefore, even if the cooling fluid supply unit is stopped in an emergency, the hydrogen-containing gas can be cooled, and spontaneous ignition of the hydrogen-containing gas when it is released into the atmosphere can be suppressed. This improves the safety of the hydrogen production plant.

[0063] In addition, in the above configuration, nitrogen is supplied to the release section by the nitrogen supply section that supplies nitrogen to the production section. That is, nitrogen is supplied to both the production section and the release section from the same device (nitrogen supply section). This allows for a reduction in the number of parts compared to when a separate device is provided to supply nitrogen to the release section. This also allows for cost reduction. Also, space can be saved.

[0064] Furthermore, in a hydrogen production plant according to a sixth aspect of the present disclosure, in any of the first to fifth aspects, the release section (30) has a storage section (33) that stores condensed water generated by condensation of a portion of the hydrogen-containing gas, and a discharge section (35) that discharges the condensed water stored in the storage section (33) to the outside of the system, and the discharge section (35) has a U-shaped pipe (35a) that has a U-shape and is filled with a liquid inside.

[0065] In the above configuration, the discharge section has a U-shaped pipe filled with a liquid. This seals the inside and outside of the discharge section with the liquid filled inside the discharge section. This prevents atmospheric air, particularly oxygen, from flowing into the inside of the discharge section through the discharge section. This prevents combustion of the hydrogen-containing gas inside the discharge section. This also prevents the hydrogen-containing gas in the discharge section from leaking into the atmosphere and combusting. This improves the safety of the hydrogen production plant.

[0066] Furthermore, the hydrogen production method according to the first aspect of the present disclosure includes a production process for producing a hydrogen-containing gas, an introduction process for introducing the hydrogen-containing gas produced in the production process into a release section (30), a supply process for supplying a cooling fluid to the hydrogen-containing gas introduced into the release section (30), and a release process for releasing the hydrogen-containing gas introduced into the release section (30) into the atmosphere.

[0067] DESCRIPTION OF SYMBOLS 1: Hydrogen production plant 10: SOEC (production section) 11: Instrument air supply section 12: City gas supply section 13: Hydrogen gas supply section 14: Nitrogen gas supply section (nitrogen supply section) 15: Make-up water supply section 16: Electrolysis air supply section 17: Electric boiler (steam generation section) 18: Heat exchanger 20: Hydrogen generation section 21: Cooler 22: Dehumidifier 23: Compressor 30: Discharge stack (discharge section) 31: Housing 31a: Large diameter section 31b: Small diameter section 31c: Discharge opening 32: Spray section (cooling fluid supply section) 33: Storage section 34: Sealing section 34a: Diameter reduction section 35: Discharge section 35a: U-shaped piping 40: Raw water supply section 41: Drainage pit 50 : Control unit 51 : Thermometer 52 : Level gauge B1 : First steam valve B2 : First hydrogen-containing gas valve B3 : Nitrogen valve B4 : Second steam valve B5 : Second hydrogen-containing gas valve B6 : Cooling water valve L1 : Nitrogen pipe (first nitrogen pipe) L2 : Make-up water pipe L3 : Steam pipe (first steam pipe) L4 : Hydrogen-containing gas pipe L5 : Branch nitrogen pipe (second nitrogen pipe) L6 : Branch make-up water pipe L7 : Branch steam pipe (second steam pipe) L8 : Branch hydrogen-containing gas pipe

Claims

1. A hydrogen production plant comprising a production unit for producing a hydrogen-containing gas, and a discharge unit into which the hydrogen-containing gas produced by the production unit is introduced and which discharges the introduced hydrogen-containing gas to the atmosphere, wherein the discharge unit has a cooling fluid supply unit for supplying a cooling fluid for cooling the hydrogen-containing gas to the hydrogen-containing gas introduced therein.

2. A steam generation unit for generating steam to be supplied to the production unit, a first steam pipe for guiding the steam generated by the steam generation unit to the production unit, and a second steam pipe for guiding the steam generated by the steam generation unit to the discharge unit, wherein the discharge unit has a discharge opening that opens toward the atmosphere and a seal unit that suppresses the inflow of the atmosphere from the discharge opening by using the steam supplied through the second steam pipe. The hydrogen production plant according to claim 1.

3. The discharge unit has a cooling fluid adjustment unit for adjusting the amount of the cooling fluid supplied from the cooling fluid supply unit, and a temperature detection unit for detecting the temperature of the hydrogen-containing gas after being cooled by the cooling fluid, and is provided with a control unit for controlling the cooling fluid adjustment unit based on the temperature of the hydrogen-containing gas detected by the temperature detection unit. The hydrogen production plant according to claim 1.

4. The discharge unit has a cooling fluid adjustment unit for adjusting the amount of the cooling fluid supplied from the cooling fluid supply unit, a storage unit for storing the condensed water generated by the condensation of the hydrogen-containing gas, and a level detection unit for detecting the liquid level of the condensed water stored in the storage unit, and is provided with a control unit for controlling the cooling fluid adjustment unit based on the liquid level detected by the level detection unit. The hydrogen production plant according to claim 1.

5. A first nitrogen pipe for guiding nitrogen gas from a nitrogen supply unit to the production unit, and a second nitrogen pipe for guiding nitrogen gas from the nitrogen supply unit to the discharge unit. The hydrogen production plant according to claim 1.

6. The discharge unit has a storage unit for storing the condensed water generated by the condensation of a part of the hydrogen-containing gas, and a discharge unit for discharging the condensed water stored in the storage unit to the outside of the system, wherein the discharge unit has a U-shaped pipe having a U shape and filled with liquid. The hydrogen production plant according to claim 1.

7. A hydrogen production method comprising: a production step of producing a hydrogen-containing gas; an introduction step of introducing the hydrogen-containing gas produced in the production step into the inside of a discharge section; a supply step of supplying a cooling fluid to the hydrogen-containing gas introduced into the inside of the discharge section; and a discharge step of discharging the hydrogen-containing gas introduced into the inside of the discharge section to the atmosphere.

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