Hydrogen production system and hydrogen production method

Abstract

The present invention provides a hydrogen production system and a hydrogen production method that reduce reliance on additional heat sources used for the regeneration of adsorbents. [Solution] The hydrogen production system comprises a steam electrolyzer 201 including an electrolytic cell configured to generate hydrogen gas from steam, a hydrogen gas supply line 410 for guiding the hydrogen gas discharged from the steam electrolyzer to a hydrogen supply target, a cooler 15 positioned on the hydrogen gas supply line for cooling the hydrogen gas, a dehumidifier 16 positioned downstream of the cooler in the hydrogen gas supply line, the dehumidifier including an adsorbent for removing moisture from the hydrogen gas flowing downstream of the cooler, a regeneration gas supply line 18 for supplying regeneration gas to the dehumidifier for regenerating the adsorbent, and a first heater 21 configured to heat the regeneration gas flowing through the regeneration gas supply line using the hydrogen gas flowing upstream of the cooler in the hydrogen gas supply line as a heat source.

Description

Technical Field

[0001] The present disclosure relates to a hydrogen production system for producing hydrogen gas using an electrolytic cell, and a hydrogen production method.

Background Art

[0002] Conventionally, a hydrogen production system that dehumidifies hydrogen gas generated using an electrolytic cell has been known. For example, the hydrogen production system disclosed in Patent Document 1 includes an electrolytic cell that generates hydrogen gas from pure water, and an adsorption tower for recovering moisture in the hydrogen gas discharged from the electrolytic cell. A system has been proposed in which the adsorbent accommodated in the adsorption tower is heated by a heater, and the moisture released from the adsorbent is discharged by the dehumidified hydrogen gas.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the heater generates heat by energization, it can be regarded as a heater that uses an additional heat source from outside the system of the hydrogen gas production system. The more the heat source from outside the system is used, the more the energy consumption for dehumidification increases.

[0005] An object of the present disclosure is to provide a hydrogen production system and a hydrogen production method that reduce the dependence on an additional heat source used for regeneration of an adsorbent.

Means for Solving the Problems

[0006] The hydrogen production system according to at least one embodiment of the present disclosure is A steam electrolysis apparatus including an electrolytic cell configured to generate hydrogen gas from water vapor, A hydrogen gas supply line for guiding the hydrogen gas discharged from the steam electrolysis apparatus to a hydrogen supply target, A cooler is placed on the hydrogen gas supply line for cooling the hydrogen gas, A dehumidifier located downstream of the cooler in the hydrogen gas supply line, A dehumidifier containing an adsorbent for removing moisture from the hydrogen gas flowing downstream of the cooler, A regeneration gas supply line for supplying a regeneration gas to the dehumidifier to regenerate the adsorbent, A first heater configured to heat the regenerating gas flowing through the regenerating gas supply line using the hydrogen gas flowing upstream of the cooler in the hydrogen gas supply line as a heat source, It is equipped with.

[0007] A hydrogen production method according to at least one embodiment of this disclosure is A hydrogen production method comprising supplying hydrogen gas generated by supplying water vapor to a water vapor electrolytic device including a solid oxide type electrolytic cell, and supplying the hydrogen gas to a target for hydrogen supply, In a hydrogen gas supply line connecting the steam electrolysis apparatus and the hydrogen supply target, a cooling step is performed in which the hydrogen gas is cooled using a cooler, In the hydrogen gas supply line, a dehumidification step is performed in which moisture is removed from the hydrogen gas flowing downstream of the cooler using a dehumidifier, A regeneration gas supply step involves supplying a regeneration gas to the dehumidifier in order to regenerate the adsorbent of the dehumidifier, A first heating step in which the regenerating gas is heated using the hydrogen gas flowing upstream of the cooler in the hydrogen gas supply line as a heat source, It is equipped with. [Effects of the Invention]

[0008] This disclosure provides a hydrogen production system and a hydrogen production method that reduce reliance on an additional heat source used for regenerating the adsorbent. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of a hydrogen production system according to one embodiment. [Figure 2A] This is a schematic diagram of a hydrogen gas supply system according to one embodiment (first example). [Figure 2B] This is a schematic diagram of a hydrogen gas supply system according to one embodiment (second example). [Figure 3] This is a schematic diagram of a controller according to one embodiment. [Figure 4] This is a schematic diagram of a dehumidifier according to one embodiment. [Figure 5A] This is a schematic diagram showing the operating pattern of a pair of parallel dehumidifiers according to one embodiment. [Figure 5B] This is another schematic diagram showing the operating pattern of a pair of parallel dehumidifiers according to one embodiment. [Figure 6] This is a flowchart of a hydrogen gas production method according to one embodiment. [Figure 7] This is a schematic diagram of a modified hydrogen gas supply system. [Modes for carrying out the invention]

[0010] Hereinafter, several embodiments of this disclosure will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described or shown in the drawings as embodiments are not intended to limit the scope of this disclosure, but are merely illustrative examples. For example, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" should not only strictly describe such arrangements, but also describe states of relative displacement with tolerances or angles or distances that allow for the same function to be achieved. For example, expressions indicating that things such as "identical", "equal", and "homogeneous" are in an equal state shall represent not only a strictly equal state but also a state in which there is a tolerance or a difference within the range where the same function can be obtained. For example, expressions representing shapes such as a rectangular shape or a cylindrical shape shall represent not only shapes such as a rectangular shape or a cylindrical shape in a geometrically strict sense but also shapes including concave-convex portions, chamfered portions, etc. within the range where the same effect can be obtained. On the other hand, the expressions "comprising", "including", or "having" for one component are not exclusive expressions excluding the existence of other components. Note that the same reference numerals may be given to similar configurations and the description may be omitted.

[0011] <Configuration of the hydrogen production system of the present disclosure> Referring to FIG. 1, the hydrogen production system 310 will be described. The hydrogen production system 310 is, as an example, a system of a pressurized solid oxide electrolysis cell (pressurized SOEC), and includes a steam electrolyzer 201. The steam electrolyzer 201 is provided with an electrolysis cell 105 for electrolyzing steam and a power supply device 650 for applying a voltage to the electrolysis cell 105. Further, the hydrogen production system 310 includes a steam generator 343 for recovering the excess heat of the electrolysis cell 105 and generating and heating the steam supplied to the electrolysis cell 105, an oxidizing gas cooler 512, and the like.

[0012] The electrolysis cell 105 is a solid oxide electrolysis cell (SOEC; Solid Oxide Electrolysis Cell) configured to generate hydrogen gas from steam. In the present embodiment, the supplied steam is pressurized steam, and the electrolysis cell 105 is a pressurized SOEC. The electrolysis cell 105 includes a hydrogen electrode 109, an oxygen electrode 113, and a solid electrolyte 111 provided between the hydrogen electrode 109 and the oxygen electrode 113. Although only one electrolysis cell 105 is schematically drawn in FIG. 1, a configuration in which a plurality of electrolysis cells 105 are housed in the steam electrolyzer 201 may also be used. The power supply device 650 is configured to apply a voltage between the hydrogen electrode 109 and the oxygen electrode 113.

[0013] The hydrogen electrode 109 is connected to a steam supply main pipe 207 through which steam supplied to the hydrogen electrode 109 flows, and to a generated hydrogen discharge main pipe 209 through which hydrogen gas discharged from the hydrogen electrode 109 flows. The steam supply main pipe 207 is connected to a feedwater line 340 via a raw material gas supply line 346 and a steam supply line 344, and a feedwater pump 341 is provided in the feedwater line 340. Downstream of the feedwater pump 341 is a flow control valve 342 (or flow control device) that controls the feedwater flow rate. The steam generator 343 is connected to the steam supply line 344 in series with the flow control valve 342.

[0014] One end of the hydrogen gas recirculation line 9 is connected to the connection point Q between the steam supply line 344 and the raw material gas supply line 346. The other end of the hydrogen gas recirculation line 9 branches off from the hydrogen gas supply line 410, and the hydrogen gas extracted from the hydrogen gas supply line 410 by the blower 20 and flowing through the hydrogen gas recirculation line 9 merges with the water vapor from the steam supply line 344 at the connection point Q. The raw material gas, containing water vapor and hydrogen gas, is supplied to the hydrogen electrode 109 in the steam electrolysis apparatus 201 via the raw material gas supply line 346. The temperature of the raw material gas flowing into the steam electrolysis apparatus 201 is approximately 200 to 350°C. A superheater may be placed on the raw material gas supply line 346, and the water vapor contained in the raw material gas may be superheated in the superheater. The hydrogen gas generated at the hydrogen electrode 109 is removed from the hydrogen gas supply line 410 via the generated hydrogen discharge main pipe 209. The temperature of the hydrogen gas discharged from the hydrogen generation discharge main pipe 209 is approximately 300°C to 400°C. The hydrogen gas supply line 410 is configured to guide the hydrogen gas to the hydrogen supply target 3. The hydrogen supply target 3 is equipment that stores or consumes hydrogen, which may be hydrogen gas or liquid hydrogen. For example, the hydrogen supply target 3 may be a hydrogen gas tank that stores hydrogen gas.

[0015] The oxygen electrode 113 is connected to an oxidizing gas supply line 513 through which an oxidizing gas containing oxygen (e.g., air) supplied to the oxygen electrode 113 flows, and to an oxidizing gas discharge line 514 through which the exhaust gas of the oxidizing gas discharged from the oxygen electrode 113 flows. The oxidizing gas intake line 510 includes an oxidizing gas compressor 511 for compressing the oxidizing gas and an oxidizing gas cooler 512 for cooling the pressurized oxidizing gas. The oxidizing gas intake line 510 is connected to the oxidizing gas supply line 513 and supplies oxidizing gas at the desired temperature, pressure, and flow rate to the steam electrolysis device 201. The oxidizing gas discharge line 514 is equipped with a steam generator 343 and is connected to an expander (power turbine) 515 driven by the exhaust oxidizing gas after heat recovery. The exhaust oxidizing gas, for which power is recovered by the expander 515, is discharged to the outside through the vent stack 517 via the exhaust oxidizing gas discharge line 516.

[0016] <Operation of Hydrogen Production System 310 (Operating Method)> Next, the operation (operating method) of the hydrogen production system 310 according to the embodiment of this disclosure will be described. Water from the water source flows through the water supply line 340 by the water supply pump 341 and is heated in the steam generator 343 by an operation described later to become pressurized steam. The amount of water supplied is determined based on the system water vapor utilization rate Uss, which is the ratio of the amount of water vapor electrolyzed to the amount of water (water vapor) supplied to the electrolysis system from an external source. The pressurized steam generated in the steam generator 343 flows through the steam supply line 344 and merges with hydrogen gas at connection point Q. The raw material gas, which contains hydrogen gas and steam, flows through the raw material gas supply line 346 and is supplied to the hydrogen electrode 109. Because hydrogen gas is included in the raw material gas, oxidation of the metal on the hydrogen electrode side of the raw material gas supply line 346 and the steam electrolysis device 201 is prevented, and the module steam utilization rate Usm in the electrolysis reaction can be adjusted to a desired state by adjusting the flow rate of hydrogen gas returning to connection point Q. Here, the module steam utilization rate Usm is the ratio of the amount of steam electrolyzed to the amount of steam supplied to the hydrogen electrode 109. Meanwhile, the oxidizing gas compressed by the oxidizing gas compressor 511 is adjusted to a desired temperature in the oxidizing gas cooler 512 located in the oxidizing gas intake line 510, and then flows through the oxidizing gas supply line 513 to the oxygen electrode 113, thereby maintaining the operating temperature of the steam electrolysis apparatus 201 at an appropriate value.

[0017] The power supply unit 650 applies a DC voltage between the hydrogen electrode 109 and the oxygen electrode 113, causing the water vapor in the hydrogen electrode 109 to be electrolyzed, generating hydrogen and oxygen ions (O2-) (see reaction equation (1) below). The oxygen ions pass through the solid electrolyte 111 and become oxygen at the oxygen electrode 113 (see reaction equation (2) below). The hydrogen gas flowing out of the hydrogen electrode 109 contains water vapor, and this water vapor-containing hydrogen gas flows through the hydrogen gas supply line 410. A portion of the hydrogen gas flowing through the hydrogen gas supply line 410 flows through the hydrogen gas recirculation line 9 and returns to the raw material gas supply line 346, while the remaining hydrogen gas flows toward the hydrogen supply target 3. The oxidizing gas discharge line 514 is connected to the heating side line of the steam generator 343 and is used as a heating medium for the steam generator 343. Since the heat-recovered exhaust oxidizing gas is pressurized, it is supplied to the expander (power turbine) 515, and power recovery for driving the oxidizing gas compressor 511 can be performed, thereby reducing power consumption. H2O + 2e- → H2 + O2- ... (1) 2O2- → O2 + 4e- ···(2)

[0018] In the following, the supply system for hydrogen gas (generated hydrogen) extracted from the steam electrolysis unit 201 will be referred to as "hydrogen gas supply system 2".

[0019] <Hydrogen gas supply system 2> Figure 2A is a schematic diagram (first example) of a hydrogen gas supply system 2 according to one embodiment of the present disclosure. The hydrogen gas supply system 2 includes a hydrogen gas supply line 410 for guiding hydrogen gas discharged from the hydrogen discharge main pipe 209 of the steam electrolysis device 201 to the hydrogen supply target 3. A first heater 21, a cooler 15, and a gas-liquid separator 15A are arranged on the hydrogen gas supply line 410 in order from the upstream side. Furthermore, the hydrogen gas supply system 2 includes a dehumidifier 16 located downstream of the gas-liquid separator 15A on the hydrogen gas supply line 410, and a hydrogen gas compressor 6 located downstream of the dehumidifier 16 on the hydrogen gas supply line 410.

[0020] The cooler 15 is configured to cool the hydrogen gas using a refrigerant, such as cooling water. As just one example, the temperature of the hydrogen gas discharged from the cooler 15 is approximately 50°C. The gas-liquid separator 15A is configured to separate the water condensed in the cooler 15 from the hydrogen gas. The dehumidifier 16 contains an adsorbent 14 to further remove moisture (humidity) from the hydrogen gas after the condensed water has been separated in the gas-liquid separator 15A. This moisture originates from the water vapor accompanying the hydrogen gas discharged from the hydrogen-generated discharge main pipe 209 that was not condensed and separated in the cooler 15 and the gas-liquid separator 15A. Note that the cooler 15 and the gas-liquid separator 15A may be integrated into a single structure. Furthermore, the water removed by the gas-liquid separator 15A can be returned to the water supply line 340 and used as a raw material for steam supply, thereby reducing the amount of water supplied.

[0021] The hydrogen gas supply line 410 includes a first hydrogen gas supply line 41 connected to the steam electrolyzer 201 and the cooler 15, and a second hydrogen gas supply line 42 connected to the dehumidifier 16 and the hydrogen supply target 3. The hydrogen gas recirculation line 9 branches off from the first hydrogen gas supply line 41 at branching point R and connects to the steam supply line 344 and the raw material gas supply line 346 at connection point Q. The hydrogen gas compressor 6 is located on the second hydrogen gas supply line 42.

[0022] The adsorbent 14 of the dehumidifier 16 requires a regeneration process to desorb the adsorbed moisture. The hydrogen gas supply system 2 according to this embodiment further includes a regeneration gas supply line 18 for supplying regeneration gas to the dehumidifier 16 to regenerate the adsorbent 14, and a regeneration gas booster blower 23 for returning the dehumidified regeneration gas (hydrogen gas) to the hydrogen gas recirculation line 9. The regeneration gas supply line 18 illustrated in Figure 2A branches off from the second hydrogen gas supply line 42 and is configured to return the dehumidified hydrogen gas extracted from the second hydrogen gas supply line 42 to the dehumidifier 16 as the regeneration gas for the adsorbent 14. In other words, in the embodiment shown in Figure 2A, the regeneration gas is synonymous with the dehumidified hydrogen gas. The regeneration gas supply line 18 illustrated in Figure 2A branches off from the second hydrogen gas supply line 42 upstream of the hydrogen gas compressor 6, but the disclosure is not limited thereto. The regeneration gas supply line 18 may also branch off from the second hydrogen gas supply line 42 downstream of the hydrogen gas compressor 6 (not shown). In this case, the regeneration gas booster blower 23 can be made unnecessary.

[0023] Although Figure 2A, a schematic diagram, depicts a single dehumidifier 16 on the second hydrogen gas supply line 42, the embodiment shown in the same figure does not exclude configurations in which multiple dehumidifiers 16 are arranged in parallel on the second hydrogen gas supply line 42 (including configurations in which multiple dehumidifiers 16 are switched at regular time intervals to alternately perform hydrogen gas dehumidification and adsorbent regeneration). In other words, the number of dehumidifiers 16 may be one, two, or three or more. If there is one dehumidifier 16, it may be a continuous operation type that can simultaneously perform dehumidification using the adsorbent 14 and regeneration of the adsorbent 14. If there are two or more dehumidifiers 16, it may be a switching type that switches its own operation between dehumidification and regeneration (details of the embodiment with two dehumidifiers 16 will be described later).

[0024] The hydrogen gas supply system 2 further includes a first heater 21 and a second heater 22, each configured to heat the regenerating gas flowing through the regenerating gas supply line 18.

[0025] The first heater 21 is configured to heat the regenerating gas using hydrogen gas flowing upstream of the cooler 15 as its heat source. In the example shown in Figure 2A, the heat source for the first heater 21 is the hydrogen gas flowing through the hydrogen gas recirculation line 9. That is, the first heater 21 is located on the first hydrogen gas supply line 41 and the regenerating gas supply line 18, downstream of the branching point R of the hydrogen gas recirculation line 9. In the second example shown in Figure 2B, the heat source for the first heater 21 is the hydrogen gas flowing through the hydrogen gas recirculation line 9. That is, the first heater 21 is located on the hydrogen gas recirculation line 9 and the regenerating gas supply line 18.

[0026] The second heater 22, illustrated in Figures 2A and 2B, is configured to heat the regeneration gas using an additional heat source different from the hydrogen gas. While this is just one example, the additional heat source is a heat transfer medium at a higher temperature than the regeneration gas, and the second heater 22 is located on the heat transfer medium line 39 through which the heat transfer medium flows and on the regeneration gas supply line 18. A heat transfer medium flow control valve 96 is located on the heat transfer medium line 39, allowing the inflow rate of the heat transfer medium into the second heater 22 to be adjusted.

[0027] The heat transfer medium may be an oxidizing gas discharged from the oxygen electrode 113 of the steam electrolysis device 201. In other words, the heat transfer medium line 39 may lead the oxidizing gas extracted from the oxidizing gas discharge line 514 to the second heater 22 as the heat transfer medium.

[0028] In the embodiment illustrated in Figures 2A and 2B, the second heater 22 is located downstream of the first heater 21 in the regeneration gas supply line 18. The regeneration gas, heated sequentially by the first heater 21 and the second heater 22, flows from the regeneration gas supply line 18 into the dehumidifier 16 to heat and regenerate the adsorbent 14.

[0029] Furthermore, the second heater 22 may be located upstream of the first heater 21 in the regeneration gas supply line 18. In this case, as another example, a portion of the steam generated by the steam generator 343 may flow into the second heater 22 as a heat transfer medium. Also, the second heater 22 is not limited to using a heat transfer medium such as liquid or gas, and the second heater 22 may be a heater that generates heat when electricity is applied.

[0030] The hydrogen gas supply system 2 illustrated in Figures 2A and 2B further includes a regeneration gas return line 24 for guiding the regeneration gas (regeneration gas after it has been used to regenerate the adsorbent 14) discharged from the dehumidifier 16 to the steam electrolysis device 201. As a specific example, the regeneration gas return line 24 is configured to merge the regeneration gas with the hydrogen gas flowing through the hydrogen gas recirculation line 9. The connection point S between the regeneration gas return line 24 and the hydrogen gas recirculation line 9 is the point where the regeneration gas and hydrogen gas merge. The hydrogen gas supply system 2 further includes a blower 20 located on the hydrogen gas recirculation line 9. The blower 20 may be located downstream of the connection point S.

[0031] The operation overview of the hydrogen gas supply system 2 illustrated in Figures 2A and 2B is explained below. A portion of the hydrogen gas flowing through the first hydrogen gas supply line 41 is extracted by the hydrogen gas recirculation line 9 and drawn into the blower 20. The remaining hydrogen gas flowing through the first hydrogen gas supply line 41 flows into the cooler 15. After the water is condensed and separated from the hydrogen gas in the cooler 15 and the gas-liquid separator 15A, the hydrogen gas is further dehumidified in the dehumidifier 16 and then discharged into the second hydrogen gas supply line 42. The hydrogen gas flowing from the second hydrogen gas supply line 42 into the hydrogen gas compressor 6 is pressurized and then sent to the hydrogen supply target 3.

[0032] A portion of the hydrogen gas flowing through the second hydrogen gas supply line 42 is extracted by the regeneration gas supply line 18 as regeneration gas for regenerating the adsorbent 14 in the dehumidifier 16. The regeneration gas flowing through the regeneration gas supply line 18 is pressurized by the regeneration gas booster blower 23, then heated sequentially by the first heater 21 and the second heater 22 before flowing into the dehumidifier 16. The regeneration gas, which contains water vapor from which moisture has been desorbed from the adsorbent 14, is discharged from the dehumidifier 16 into the regeneration gas return line 24. The regeneration gas flows through the regeneration gas return line 24 and merges with the hydrogen gas flowing through the hydrogen gas recirculation line 9 at connection point S.

[0033] Blower 20 delivers the regeneration gas and hydrogen gas, which merge at connection point S, toward connection point Q. The raw material gas supply line 346 leads the raw material gas, which includes hydrogen gas and water vapor flowing into connection point Q, to the steam electrolysis device 201. The concentration of hydrogen gas in the raw material gas is approximately 3% to 50%. The main purpose of returning hydrogen gas to the steam electrolysis device 201 is to ensure a reducing atmosphere at the hydrogen electrode 109, and the concentration of hydrogen gas must remain within a predetermined range.

[0034] The technical advantages obtained by the embodiments illustrated in Figures 2A and 2B are as follows:

[0035] According to the above configuration, the hydrogen gas flowing upstream of the cooler 15 is included as a heat source for heating the regeneration gas. In other words, a portion of the heat from the hydrogen gas that was released outside the system by the cooler 15, which cools the hydrogen gas for dehumidification, is reused as a heat source for the regeneration gas of the adsorbent 14. Thus, a hydrogen production system 310 is realized that reduces the reliance on an additional heat source used for the regeneration of the adsorbent 14. Furthermore, the hydrogen gas supply system 2 does not necessarily have to include a second heater 22. In addition, the hydrogen gas supply system 2 does not necessarily have to include a regeneration gas return line 24, and the regeneration gas discharged from the dehumidifier 16 may be released outside the system. The above technical advantages can be obtained even if at least one of these modifications is applied.

[0036] Furthermore, by arranging the first heater 21 on the first hydrogen gas supply line 41 downstream of the branching point R between the hydrogen gas supply line 410 and the hydrogen gas recirculation line 9, the gas temperature at the inlet of the cooler 15 can be more effectively reduced by heating the regenerative gas, thereby reducing heat loss associated with cooling for dehumidification. In addition, since the hydrogen gas used as a heat source in the first heater 21 returns to the steam electrolysis device 201, the hydrogen gas extracted from the first hydrogen gas supply line 41 can be utilized without waste. Moreover, the flow rate of steam supplied from the steam generator 343 to the steam electrolysis device 201 can be reduced by the flow rate of steam accompanying the hydrogen gas returning to the steam electrolysis device 201 from the hydrogen gas recirculation line 9.

[0037] Furthermore, with the configuration in which the first heater 21 is located on the hydrogen gas recirculation line 9 that branches off from the hydrogen gas supply line 410, compared to the case in which the first heater 21 is located on the hydrogen gas supply line 410 which is the main flow path for hydrogen gas, it is possible to heat the regenerative gas and lower the gas temperature at the inlet of the blower 20, thereby reducing the power required for the blower 20. In addition, since the hydrogen gas used as a heat source in the first heater 21 returns to the steam electrolysis device 201, the hydrogen gas extracted from the first hydrogen gas supply line 41 can be utilized without waste. Moreover, the flow rate of steam supplied to the steam electrolysis device 201 from the steam generator 343 from the outside can be reduced by the flow rate of steam accompanying the hydrogen gas returning to the steam electrolysis device 201 from the hydrogen gas recirculation line 9, thereby increasing the system steam utilization rate.

[0038] Furthermore, with a configuration in which the regeneration gas supply line 18 guides hydrogen gas to the dehumidifier 16 as regeneration gas, it is possible to suppress the mixing of regeneration gas as an impurity into the dehumidified hydrogen gas discharged from the dehumidifier 16. Therefore, the purity of the hydrogen gas supplied to the hydrogen supply target 3 can be increased.

[0039] Furthermore, by providing a regeneration gas booster blower 23 to supply dehumidified hydrogen extracted from the hydrogen gas supply line 410 to the dehumidifier 16 as a regeneration gas, the regeneration gas necessary for the regeneration of the dehumidifier 16 can be reliably supplied.

[0040] Furthermore, in a configuration that includes a regeneration gas return line 24, the hydrogen gas used for regeneration returns to the steam electrolysis device 201, allowing the hydrogen gas extracted from the hydrogen gas supply line 410 to be utilized efficiently without being released outside the system.

[0041] Furthermore, in a configuration where the regenerating gas flowing through the regenerating gas return line 24 merges with the hydrogen gas flowing through the hydrogen gas recirculation line 9, the influence of fluctuations in the composition of the raw material gas for steam electrolysis due to changes in the flow rate of the regenerating gas associated with the adsorption and desorption of the adsorbent 14 can be reduced compared to the case where the regenerating gas return line 24 is directly connected to the steam electrolysis apparatus 201.

[0042] Furthermore, by installing the first heater 21 upstream of the blower 20 on the hydrogen gas recirculation line 9, the hydrogen gas that has served as a heat source in the first heater 21 flows into the blower 20. This lowers the inlet temperature of the blower 20, thereby reducing the power required for the blower 20.

[0043] Furthermore, in the configuration where the blower 20 is positioned downstream of the connection point S, the blower 20 combines the functions of supplying hydrogen gas flowing through the hydrogen gas recirculation line 9 to the steam electrolysis device 201 and supplying regenerative gas flowing through the regenerative gas return line 24 to the steam electrolysis device 201. Therefore, the power required for the regenerative gas booster blower 23 can be reduced. In addition, by positioning the blower 20 downstream of the first heater 21 and the connection point S, the hydrogen gas temperature at the blower inlet can be further reduced, thereby reducing the power required for the blower 20. Also, since the hydrogen gas used as a heat source in the first heater 21 returns to the steam electrolysis device 201, the hydrogen gas extracted from the first hydrogen gas supply line 41 can be utilized without waste. Furthermore, the flow rate of steam supplied from outside the system to the steam electrolytic device 201 by the steam generator 343 can be reduced by the amount of steam accompanying the hydrogen gas returning to the steam electrolytic device 201 from the hydrogen gas recirculation line 9, thereby increasing the system's steam utilization rate.

[0044] Furthermore, in the configuration in which the second heater 22 is arranged, the second heater 22 heats the regeneration gas not only in the first heater 21 but also in the second heater 22, so the temperature of the regeneration gas flowing into the dehumidifier 16 can be sufficiently raised, making it easy to adjust the temperature to a level suitable for regeneration. In addition, by supplying a portion of the heating required for the regeneration gas with the second heater 22, an increase in the load on the first heater 21 can be avoided.

[0045] <Controller 90> Figure 3 is a schematic diagram of a controller 90 according to one embodiment of the present disclosure. The controller 90 comprises a processor such as a CPU and a memory (storage medium) which may be implemented by at least one of RAM, ROM, or flash memory. The processor executes control processing according to the instructions of a program loaded into the memory. The controller 90 is an example of a computer device and may be a DCS panel that constitutes one of a plurality of control panels installed in a plant.

[0046] The functions of the controller 90 shown in the figure are outlined below. As previously described, the concentration of hydrogen gas in the raw material gas returning to the steam electrolysis device 201 must remain within a predetermined range. Therefore, it is necessary to adjust the flow rate of hydrogen gas flowing into connection point Q according to the flow rate of steam flowing through the steam supply line 344. For example, if the flow rate of steam in the steam supply line 344 decreases, it is necessary to reduce the flow rate of hydrogen gas flowing from the first hydrogen gas supply line 41 to the hydrogen gas recirculation line 9. In this case, since the amount of heat generated in the regeneration gas in the first heater 21 decreases, it is necessary to increase the amount of heat generated in the second heater 22 to maintain the amount of heat contained in the regeneration gas. The controller 90 is responsible for controlling the flow rate of hydrogen gas and the amount of heat generated in the second heater 22.

[0047] As shown in Figure 3, the controller 90 functions as a hydrogen gas flow control unit 91 and a heating control unit 92. Furthermore, it may also function as an oxidizing gas supply control and a water (steam) supply control unit within the hydrogen production system 310.

[0048] The hydrogen gas flow control unit 91 controls the flow rate of hydrogen gas returning to the steam electrolysis device 201 from the hydrogen gas recirculation line 9 according to the amount of steam flowing into the steam electrolysis device 201. As a more specific example, the hydrogen gas flow control unit 91 controls the rotation speed of the blower 20 based on the measurement value of the concentration meter 95, which measures the concentration of hydrogen gas in the raw material gas flowing into the steam electrolysis device 201 from the raw material gas supply line 346.

[0049] The heating control unit 92 controls the amount of heat transfer fluid flowing into the second heater 22 according to the flow rate of hydrogen gas as a heat source flowing into the first heater 21. As a more specific example, the temperature or flow rate of the regeneration gas flowing into the dehumidifier 16 is used as a parameter that correlates with the amount of hydrogen gas flowing into the first heater 21 as a heat source. More specifically, the heating control unit 92 controls the opening degree of the heat transfer fluid flow control valve 96 based on the measurement value of the regeneration gas measuring instrument 99 for measuring the temperature or flow rate of the regeneration gas flowing into the dehumidifier 16.

[0050] For example, when the flow rate of steam flowing through the steam supply line 344 decreases (see Figures 2A and 3), the measured value of the hydrogen gas concentration output from the concentration meter 95 to the hydrogen gas flow control unit 91 increases. At this time, the hydrogen gas flow control unit 91 sends a command to the blower 20 to reduce the rotation speed. As the amount of raw material gas flowing into the steam electrolysis device 201 decreases, the amount of hydrogen gas flowing in as a heat source to the first heater 21 decreases, and the temperature measured by the regeneration gas meter 99 decreases. At this time, the heating control unit 92 sends a command to the heat transfer medium flow control valve 96 to increase its opening. As a result, the amount of heat transfer medium flowing into the second heater 22 increases, and the amount of regeneration gas heated in the second heater 22 increases.

[0051] With the above configuration, even if the flow rate of hydrogen gas flowing through the hydrogen gas recirculation line 9 decreases, insufficient heating of the regenerating gas can be avoided, and the adsorbent 14 can be sufficiently regenerated in the dehumidifier 16.

[0052] <Dehumidifier 16> Figure 4 is a schematic diagram showing the specific configuration of a dehumidifier 16, an example in which two dehumidifiers 16 are arranged in parallel on a hydrogen gas supply line 410. The hydrogen gas supply line 410 includes a pair of parallel hydrogen gas lines 410a and 410b arranged in parallel with each other between the gas-liquid separator 15A and the hydrogen gas compressor 6. The dehumidifier 16 includes a pair of parallel dehumidifiers 16a and 16b, respectively, arranged on the pair of parallel hydrogen gas lines 410a and 410b. Adsorbent 14 is placed in each of the parallel dehumidifiers 16a and 16b.

[0053] Furthermore, upstream of the pair of parallel hydrogen gas lines 410a and 410b, a pair of hydrogen gas valves 17a and 17b are arranged on each of the parallel hydrogen gas lines 410a and 410b. The hydrogen gas valves 17a and 17b are on-off valves.

[0054] Furthermore, the regeneration gas supply line 18 includes a pair of regeneration gas extraction lines 19a, 19b and a pair of regeneration gas introduction lines 21a, 21b. In addition, hydrogen gas supply valves 35a, 35b are arranged in the hydrogen gas parallel lines 410a, 410b downstream from the branch of the regeneration gas extraction lines 19a, 19b, and operate in conjunction with the opening and closing of the hydrogen gas valves 17a, 17b.

[0055] A pair of regeneration gas extraction lines 19a and 19b are each connected to a pair of parallel hydrogen gas lines 410a and 410b. The pair of regeneration gas extraction lines 19a and 19b are configured to extract dehumidified hydrogen gas discharged from a pair of parallel dehumidifiers 16a and 16b from the pair of parallel hydrogen gas lines 410a and 410b and guide it to a heating system for regeneration gas, including a first heater 21 and a second heater 22. Each of the pair of regeneration gas extraction lines 19a and 19b is equipped with a pair of regeneration gas extraction valves 31a and 31b, which may be, for example, on-off valves.

[0056] A pair of regeneration gas introduction lines 21a and 21b are configured to guide heated regeneration gas (dehumidified hydrogen gas) discharged from the first heater 21 to a pair of parallel dehumidifiers 16a and 16b, respectively. Each of the pair of regeneration gas introduction lines 21a and 21b is equipped with a pair of regeneration gas introduction valves 34a and 34b, which may be, for example, on-off valves.

[0057] Furthermore, the regeneration gas return line 24 includes a pair of parallel regeneration gas return lines 24a and 24b for returning the regeneration gas discharged from a pair of parallel dehumidifiers 16a and 16b back to the steam electrolyzer 201. Each of the pair of parallel regeneration gas return lines 24a and 24b is provided with a pair of regeneration gas discharge valves 36a and 36b, which may be, for example, on-off valves.

[0058] Figures 5A and 5B are schematic diagrams showing the operating patterns of a pair of parallel dehumidifiers 16a and 16b. In Figure 5A, of the pair of parallel dehumidifiers 16a and 16b, parallel dehumidifier 16a performs dehumidification and parallel dehumidifier 16b performs regeneration. At this time, of the pair of hydrogen gas valves 17a and 17b, hydrogen gas valve 17a is in the open state and hydrogen gas valve 17b is in the closed state. Also, of the pair of regeneration gas extraction valves 31a and 31b, regeneration gas extraction valve 31a is in the open state and regeneration gas extraction valve 31b is in the closed state. Furthermore, of the pair of regeneration gas introduction valves 34a and 34b, regeneration gas introduction valve 34b is in the open state and regeneration gas introduction valve 34a is in the closed state. Also, of the pair of hydrogen gas supply valves 35a and 35b, hydrogen gas supply valve 35a is in the open state and hydrogen gas supply valve 35b is in the closed state. Furthermore, of the pair of regeneration gas discharge valves 36a and 36b, regeneration gas discharge valve 36a is in a closed state, and regeneration gas discharge valve 36b is in an open state.

[0059] In Figure 5A, thick arrows indicate the lines through which hydrogen gas or regenerative gas flows in the hydrogen gas supply line 410, the regenerative gas supply line 18, and the regenerative gas return line 24. The hydrogen gas discharged from the cooler 15, from which condensed water is separated in the gas-liquid separator 15A, flows through the hydrogen gas parallel line 410a of the pair of hydrogen gas parallel lines 410a and 410b, and flows into the parallel dehumidifier 16a. Dehumidified hydrogen gas is discharged from the parallel dehumidifier 16a to the downstream hydrogen gas parallel line 410a. Of the pair of regenerative gas extraction lines 19a and 19b, the regenerative gas extraction line 19a extracts dehumidified hydrogen gas from the hydrogen gas parallel line 410a downstream of the parallel dehumidifier 16a as regenerative gas, pressurizes it in the regenerative gas booster blower 23, and then leads it to the regenerative gas heating system. The regeneration gas, heated sequentially in the first heater 21 and the second heater 22, flows through the regeneration gas introduction line 21b of the pair of regeneration gas introduction lines 21a and 21b and is introduced into the parallel dehumidifier 16b. As a result, the adsorbent 14 in the parallel dehumidifier 16b is regenerated by the removal of moisture. The regeneration gas discharged from the parallel dehumidifier 16b flows through the regeneration gas parallel return line 24b and flows into the connection point S.

[0060] In Figure 5B, of the pair of parallel dehumidifiers 16a and 16b, the parallel dehumidifier 16b performs dehumidification and the parallel dehumidifier 16a performs regeneration. At this time, of the pair of hydrogen gas valves 17a and 17b, the hydrogen gas valve 17b is in the open state and the hydrogen gas valve 17a is in the closed state. Also, of the pair of regeneration gas extraction valves 31a and 31b, the regeneration gas extraction valve 31b is in the open state and the regeneration gas extraction valve 31a is in the closed state. Furthermore, of the pair of regeneration gas introduction valves 34a and 34b, the regeneration gas introduction valve 34a is in the open state and the regeneration gas introduction valve 34b is in the closed state. Also, of the pair of hydrogen gas supply valves 35a and 35b, the hydrogen gas supply valve 35a is in the closed state and the hydrogen gas supply valve 35b is in the open state, and of the pair of regeneration gas discharge valves 36a and 36b, the regeneration gas discharge valve 36a is in the open state and the regeneration gas discharge valve 36b is in the closed state. In Figure 5B, the lines through which hydrogen gas or regenerating gas flows in the hydrogen gas supply line 410, the regenerating gas supply line 18, and the regenerating gas return line 24 are indicated by thick arrows. The details are similar to those explained using Figure 5A, so a detailed explanation is omitted here.

[0061] With the above configuration, while one of the pair of parallel dehumidifiers 16a, 16b, is operating (dehumidifying), the adsorbent 14 of the other parallel dehumidifier 16b can be regenerated. And while the other parallel dehumidifier 16b is operating, the adsorbent 14 of the one parallel dehumidifier 16a can be regenerated. As a result, the hydrogen gas flowing through the hydrogen gas supply line 410 can be continuously dehumidified.

[0062] <Method for producing hydrogen gas> Figure 6 is a flowchart illustrating a method for producing hydrogen gas according to one embodiment of the present disclosure. The steps comprising this method may be performed by the controller 90, by the operator of the hydrogen production system 310, or by a combination of these. Hereinafter, "step" may be abbreviated as "S".

[0063] First, a hydrogen gas generation step (S11) is performed in which hydrogen gas is generated in the steam electrolysis apparatus 201. The generated hydrogen gas is discharged into the hydrogen gas supply line 410.

[0064] Next, a recirculation hydrogen gas extraction step (S13) is performed in which hydrogen gas flowing through the first hydrogen gas supply line 41 is extracted and guided to the steam electrolysis device 201. Then, a hydrogen gas cooling step (S15) is performed in which the hydrogen gas flowing through the first hydrogen gas supply line 41 that is not extracted is cooled using the cooler 15.

[0065] Next, a condensed water separation step (S16) is performed in which condensed water in the hydrogen gas discharged from the cooler 15 is separated by a gas-liquid separator 15A. Furthermore, a hydrogen gas dehumidification step (S17) is performed in which moisture is removed from the hydrogen gas from which the water has been separated using a dehumidifier 16. The dehumidified hydrogen gas discharged from the dehumidifier 16 flows through the second hydrogen gas supply line 42 toward the hydrogen supply target 3. Subsequently, a regeneration gas extraction step (S19) is performed in which the dehumidified hydrogen gas is extracted from the second hydrogen gas supply line 42 as regeneration gas. After the extracted regeneration gas is pressurized, it flows through the regeneration gas supply line 18. Next, a first heating step (S21) is performed in which the regeneration gas is heated using the first heater 21, and a second heating step (S23) is performed in which the regeneration gas is heated using the second heater 22. Subsequently, a regeneration gas supply step (S25) is performed in which the heated regeneration gas is supplied to the dehumidifier 16. After S25, a regeneration gas return step (S27) is performed, in which the regeneration gas discharged from the dehumidifier 16 is guided to the steam electrolysis device 201 via the regeneration gas return line 24. After that, this flowchart ends.

[0066] For example, if the dehumidifier 16 includes a pair of parallel dehumidifiers 16a and 16b, hydrogen gas may be introduced to one of the parallel dehumidifiers 16a in S17. In this case, hydrogen gas is extracted from the regeneration gas extraction line 19a in S19. The regeneration gas heated in S21 and S23 is then introduced to the other parallel dehumidifier 16b via the regeneration gas introduction line 21b (S25). The regeneration gas discharged from the parallel dehumidifier 16b flows into the connection point S from the regeneration gas parallel return line 24b and returns to the water vapor electrolysis device 201.

[0067] The first heater 21 may be positioned downstream of the second heater 22. In this case, the order of steps S21 and S23 will be reversed.

[0068] <Variation> Figure 7 is a schematic diagram showing a modified hydrogen gas supply system 2A. In Figure 7, the same components as in the hydrogen gas supply system 2 shown in Figure 2A are given the same reference numerals.

[0069] The hydrogen gas supply system 2A shown in Figure 7 includes a regeneration gas supply line 18A. The regeneration gas supply line 18A is configured to lead a regeneration gas different from hydrogen gas to the dehumidifier 16. The regeneration gas supply line 18A is connected to a regeneration gas supply source 60. The regeneration gas supplied from the supply source 60 may be, for example, nitrogen. The regeneration gas flowing through the regeneration gas supply line 18A is heated in the first heater 21 and the second heater 22, and then supplied to the dehumidifier 16 to perform a regeneration treatment on the adsorbent 14. The regeneration gas discharged from the dehumidifier 16 is discharged outside the system via a regeneration gas discharge line 65.

[0070] With the above configuration, there is no need to extract the hydrogen gas discharged from the dehumidifier 16 as a regenerative gas. This simplifies or eliminates the hydrogen gas extraction structure.

[0071] <Summary> The contents described in some of the embodiments above can be understood, for example, as follows:

[0072] 1) A hydrogen production system (310) according to at least one embodiment of the present disclosure is A steam electrolysis apparatus (201) including an electrolytic cell (105) configured to generate hydrogen gas from water vapor, A hydrogen gas supply line (410) for guiding the hydrogen gas discharged from the steam electrolysis apparatus to the hydrogen supply target (3), A cooler (15) for cooling the hydrogen gas is placed on the hydrogen gas supply line, A dehumidifier (16) located downstream of the cooler in the hydrogen gas supply line, comprising an adsorbent (14) for removing moisture from the hydrogen gas flowing downstream of the cooler, A regeneration gas supply line (18, 18A) for supplying a regeneration gas to the dehumidifier to regenerate the adsorbent, A first heater (21) is configured to heat the regenerating gas flowing through the regenerating gas supply line using the hydrogen gas flowing upstream of the cooler in the hydrogen gas supply line as a heat source, It is equipped with.

[0073] According to the configuration described in 1) above, the hydrogen gas flowing upstream of the cooler is included as a heat source for heating the regeneration gas. In other words, a portion of the heat from the hydrogen gas that would otherwise be released outside the system by the cooler used for dehumidification is utilized as a heat source for the adsorbent regeneration gas. Thus, a hydrogen production system is realized that reduces the reliance on an additional heat source used for adsorbent regeneration.

[0074] 2) In some embodiments, the hydrogen production system described in 1) above is Further comprising a hydrogen gas recirculation line (9) that branches off from the hydrogen gas supply line upstream of the cooler and returns the hydrogen gas extracted from the hydrogen gas supply line back to the steam electrolysis device, The first heater is positioned on the hydrogen gas recirculation line.

[0075] According to the configuration described in 2) above, the first heater is positioned on the hydrogen gas recirculation line branching off from the hydrogen gas supply line, thereby heating the regenerative gas and lowering the temperature of the hydrogen gas flowing through the hydrogen gas recirculation line. Furthermore, since the hydrogen gas used as a heat source in the first heater returns to the steam electrolysis device, the hydrogen gas extracted from the hydrogen gas supply line can be utilized without waste. In addition, the flow rate of steam supplied to the steam electrolysis device from an external steam generator can be reduced by the amount of steam carried with the hydrogen gas returning to the steam electrolysis device from the hydrogen gas recirculation line, thereby improving the system steam utilization rate.

[0076] 3) In some embodiments, the hydrogen production system is as described in 2) above, The regeneration gas supply line branches off from the hydrogen gas supply line downstream of the dehumidifier and is configured to guide the dehumidified hydrogen gas extracted from the hydrogen gas supply line to the dehumidifier as the regeneration gas.

[0077] According to the configuration described in 3) above, since the regeneration gas is hydrogen gas, it is possible to suppress the mixing of impurities into the dehumidified hydrogen gas discharged from the dehumidifier. Therefore, the purity of the hydrogen gas supplied to the target of hydrogen supply can be increased.

[0078] 4) In some embodiments, the hydrogen production system is as described in 3) above, The system further includes a regeneration gas booster blower (23) positioned on the regeneration gas supply line to supply the dehumidified hydrogen gas extracted from the hydrogen gas supply line to the dehumidifier as the regeneration gas.

[0079] According to the configuration described in 4) above, the regeneration gas necessary for regenerating the adsorbent can be reliably supplied to the dehumidifier.

[0080] 5) In some embodiments, the hydrogen production system described in 4) above is The system further includes a regeneration gas return line (24) for guiding the regeneration gas discharged from the dehumidifier to the water vapor electrolysis device.

[0081] According to the configuration described in 5) above, the hydrogen gas used for regeneration is returned to the steam electrolysis device, so the hydrogen gas extracted from the hydrogen gas supply line can be used without waste.

[0082] 6) In some embodiments, the hydrogen production system is as described in 5) above, The regeneration gas return line is configured to merge the regeneration gas with the hydrogen gas flowing through the hydrogen gas recirculation line.

[0083] According to the configuration in 6) above, compared to the case where the regeneration gas return line is connected to the steam electrolysis apparatus, the influence of fluctuations in the composition of the raw material gas for steam electrolysis due to changes in the flow rate of the regeneration gas associated with the adsorption and desorption of the adsorbent can be reduced.

[0084] 7) In some embodiments, the hydrogen production system described in 6) above is The system further includes a blower (20) positioned on the hydrogen gas recirculation line downstream of the point where the regenerating gas flowing through the regenerating gas return line and the hydrogen gas flowing through the hydrogen gas recirculation line merge (connection point S).

[0085] According to the configuration described in 7) above, the blower can combine the functions of supplying hydrogen gas flowing through the hydrogen gas recirculation line to the steam electrolysis device and supplying regenerative gas flowing through the regenerative gas return line to the steam electrolysis device. Therefore, the power of the regenerative gas booster blower can be reduced.

[0086] 8) In some embodiments, the hydrogen production system described in 7) above is The first heater is configured to heat the regenerating gas using the hydrogen gas flowing upstream of the blower on the hydrogen gas recirculation line as a heat source.

[0087] According to the configuration described in 8) above, the hydrogen gas that has served as a heat source in the first heater flows into the blower. This lowers the inlet temperature of the blower and reduces the power required for the blower.

[0088] 9) In some embodiments, the hydrogen production system described in any of 2) to 8) above is The system further includes a second heater (22) positioned on the hydrogen gas recirculation line and configured to heat the regenerating gas using an additional heat source different from the hydrogen gas.

[0089] According to the configuration described in 9) above, since the second heater heats the regeneration gas as well as the first heater, even if the amount of heating in the first heater fluctuates due to changes in the hydrogen production amount or the system steam utilization rate, the temperature of the regeneration gas flowing into the dehumidifier can be set to the desired value. By supplying a portion of the amount of heating required for the regeneration gas with the second heater, an increase in the load on the first heater can be avoided.

[0090] 10) In some embodiments, the hydrogen production system described in 9) above is A hydrogen gas flow control unit (91) for controlling the flow rate of hydrogen gas returning to the steam electrolysis apparatus from the hydrogen gas recirculation line, in accordance with the amount of water vapor flowing into the steam electrolysis apparatus, A heating control unit (92) controls the amount of heat transfer fluid flowing into the second heater as an additional heat source, according to the flow rate of hydrogen gas flowing into the first heater, and It is equipped with.

[0091] According to the configuration described in 10) above, when the flow rate of hydrogen gas returning from the hydrogen gas recirculation line to the steam electrolysis device decreases due to the control of the hydrogen gas flow control unit, the flow rate of hydrogen gas flowing into the first heater as a heat source decreases. As a result, the amount of heat generated for the regeneration gas in the first heater decreases. In this case, the heating control unit can increase the amount of heat generated in the second heater by increasing the amount of heat transfer gas flowing into the second heater. Thus, insufficient heating of the regeneration gas can be avoided, and the adsorbent in the dehumidifier can be sufficiently regenerated.

[0092] 11) In some embodiments, a hydrogen production system according to any one of 1) to 10) above, The hydrogen gas supply line includes a pair of parallel hydrogen gas lines (410a, 410b) arranged in parallel with each other between the cooler and the hydrogen supply target. The dehumidifier includes a pair of parallel dehumidifiers (16a, 16b) respectively arranged on the pair of parallel hydrogen gas lines, The aforementioned regeneration gas supply line is A pair of regenerative gas extraction lines (19a, 19b) for extracting the dehumidified hydrogen gas discharged from the pair of parallel dehumidifiers from the pair of parallel hydrogen gas lines and guiding it to the first heater, A pair of regenerative gas introduction lines (21a, 21b) for guiding the heated regenerative gas discharged from the first heater to the pair of parallel dehumidifiers, Includes.

[0093] According to the configuration described in 11) above, the adsorbent in one of the pair of parallel dehumidifiers can be regenerated while the other is operating, and the adsorbent in the other can be regenerated while the other is operating. This allows for continuous dehumidification of the hydrogen gas flowing through the hydrogen gas supply line.

[0094] 12) In some embodiments, the hydrogen production system is as described in 1) or 2) above, The regeneration gas supply line is configured to guide a gas different from the hydrogen gas to the dehumidifier as the regeneration gas.

[0095] According to the configuration described in 12) above, there is no need to extract the hydrogen gas discharged from the dehumidifier as a regenerating gas. Therefore, the hydrogen gas extraction structure can be simplified or omitted.

[0096] 13) In some embodiments, a hydrogen production system according to any one of 1) to 12) above, The system further includes a gas-liquid separator (15A) positioned between the cooler and the dehumidifier on the hydrogen gas supply line for separating condensed water from the hydrogen gas discharged from the cooler.

[0097] According to the configuration described in item 13) above, condensed water in the cooler can be recovered from hydrogen gas.

[0098] 14) A hydrogen production method according to at least one embodiment of the present disclosure is A hydrogen production method comprising supplying hydrogen gas generated by supplying water vapor to a water vapor electrolytic device (201) including a solid oxide type electrolytic cell (105) to a hydrogen supply target (3), In the hydrogen gas supply line (410) connecting the steam electrolysis apparatus and the hydrogen supply target, a cooling step (S15) is performed in which the hydrogen gas is cooled using a cooler (15), In the hydrogen gas supply line, a dehumidification step (S17) is performed to remove moisture from the hydrogen gas flowing downstream of the cooler using a dehumidifier (16), A regeneration gas supply step (S25) is performed to supply a regeneration gas to the dehumidifier in order to regenerate the adsorbent (14) of the dehumidifier, A first heating step (S21) in which the regenerating gas is heated using the hydrogen gas flowing upstream of the cooler in the hydrogen gas supply line as a heat source, It is equipped with.

[0099] According to the configuration in 14) above, the same technical advantages as in 1) above can be obtained. [Explanation of symbols]

[0100] 2,2A: Hydrogen gas supply system 3: Target of hydrogen supply 6: Hydrogen gas compressor 9: Hydrogen gas recirculation line 14: Adsorbent 15:Cooler 15A: Gas-liquid separator 16:Dehumidifier 16a,16b: Parallel dehumidifier 17a, 17b: Hydrogen gas valve 18,18A: Regeneration gas supply line 19a, 19b: Gas extraction line for regeneration 20: Blower 21: 1st heater 21a, 21b: Regeneration gas introduction line 22:Second heater 23: Gas booster blower for regeneration 24: Regeneration gas return line 24a, 24b: Parallel return line for regenerated gas 31a, 31b: Gas extraction valve for regeneration 34a, 34b: Gas introduction valve for regeneration 35a, 35b: Hydrogen gas supply valve 36a, 36b: Gas discharge valve for regeneration 39: Heat transfer fluid line 41: First hydrogen gas supply line 42: Second hydrogen gas supply line 60: Source 65: Regenerative gas discharge line 90: Controller 91: Hydrogen gas flow control unit 92: Heating control unit 95: Concentration meter 96: Heat medium flow control valve 99: Gas measuring instrument for regeneration 105: Electrolytic cell 109: Hydrogen electrode 111: Solid electrolyte 113: Oxygen electrode 201: Steam electrolysis apparatus 207: Steam supply main pipe 209: Hydrogen-generated discharge main pipe 310: Hydrogen production system 340: Water supply line 341: Water supply pump 342: Flow control valve 343: Steam generator 344: Steam supply line 346: Raw material gas supply line 410: Hydrogen gas supply line 410a, 410b: Hydrogen gas parallel line 510: Oxidizing gas intake line 511: Oxidizing gas compressor 512: Oxidizing gas cooler 513: Oxidizing gas supply line 514: Oxidizing gas emission line 515: Expander 516: Oxidizing gas emission line 517: Vent Stack 650: Power supply Q,S: Connection point

Claims

1. A steam electrolysis apparatus including an electrolytic cell configured to generate hydrogen gas from water vapor, A hydrogen gas supply line for guiding the hydrogen gas discharged from the steam electrolysis apparatus to a hydrogen supply target, A cooler is placed on the hydrogen gas supply line for cooling the hydrogen gas, A dehumidifier located downstream of the cooler in the hydrogen gas supply line, comprising an adsorbent for removing moisture from the hydrogen gas flowing downstream of the cooler, A regeneration gas supply line for supplying a regeneration gas to the dehumidifier to regenerate the adsorbent, A first heater configured to heat the regenerating gas flowing through the regenerating gas supply line using the hydrogen gas flowing upstream of the cooler in the hydrogen gas supply line as a heat source, A hydrogen production system equipped with the following features.

2. Further comprising a hydrogen gas recirculation line that branches off from the hydrogen gas supply line upstream of the cooler and returns the hydrogen gas extracted from the hydrogen gas supply line to the steam electrolysis apparatus, The first heater is positioned on the hydrogen gas supply line downstream of the branch of the hydrogen gas recirculation line. The hydrogen production system according to claim 1.

3. The regeneration gas supply line branches off from the hydrogen gas supply line downstream of the dehumidifier and is configured to guide the dehumidified hydrogen gas extracted from the hydrogen gas supply line to the dehumidifier as the regeneration gas. The hydrogen production system according to claim 2.

4. The system further comprises a regenerative gas boost blower positioned on the regenerative gas supply line to supply the dehumidified hydrogen gas extracted from the hydrogen gas supply line to the dehumidifier as the regenerative gas. The hydrogen production system according to claim 3.

5. The system further comprises a regeneration gas return line for guiding the regeneration gas discharged from the dehumidifier to the steam electrolysis device. The hydrogen production system according to claim 4.

6. The regeneration gas return line is configured to merge the regeneration gas with the hydrogen gas flowing through the hydrogen gas recirculation line. The hydrogen production system according to claim 5.

7. The system further comprises a blower positioned downstream of the point where the regenerating gas flowing through the regenerating gas return line and the hydrogen gas flowing through the hydrogen gas recirculation line merge, and located on the hydrogen gas recirculation line. The hydrogen production system according to claim 6.

8. The first heater is configured to heat the regenerating gas using the hydrogen gas flowing upstream of the blower on the hydrogen gas recirculation line as a heat source. The hydrogen production system according to claim 7.

9. The system further comprises a second heater positioned on the aforementioned regeneration gas supply line and configured to heat the regeneration gas using an additional heat source different from the hydrogen gas. A hydrogen production system according to any one of claims 2 to 8.

10. A hydrogen gas flow control unit for controlling the flow rate of hydrogen gas returning to the steam electrolysis apparatus from the hydrogen gas recirculation line, in accordance with the amount of steam flowing into the steam electrolysis apparatus, A heating control unit for controlling the amount of heat transfer fluid flowing into the second heater as an additional heat source, according to the flow rate of hydrogen gas flowing into the first heater, and Equipped with The hydrogen production system according to claim 9.

11. The hydrogen gas supply line includes a pair of parallel hydrogen gas lines arranged in parallel with each other between the cooler and the hydrogen supply target, The dehumidifier includes a pair of parallel dehumidifiers, each arranged on the pair of parallel hydrogen gas lines, The aforementioned regeneration gas supply line is A pair of regenerative gas extraction lines for extracting the dehumidified hydrogen gas discharged from the pair of parallel dehumidifiers from the pair of parallel hydrogen gas lines and guiding it to the first heater, A pair of regenerative gas introduction lines for guiding the heated regenerative gas discharged from the first heater to the pair of parallel dehumidifiers, including A hydrogen production system according to any one of claims 1 to 6.

12. The regeneration gas supply line is configured to guide a gas different from the hydrogen gas to the dehumidifier as the regeneration gas. A hydrogen production system according to claim 1 or 2.

13. The hydrogen gas supply line further comprises a gas-liquid separator positioned between the cooler and the dehumidifier for separating condensed water from the hydrogen gas discharged from the cooler. A hydrogen production system according to claim 1 or 2.

14. A hydrogen production method comprising supplying hydrogen gas generated by supplying water vapor to a water vapor electrolytic device including a solid oxide type electrolytic cell, and supplying the hydrogen gas to a target for hydrogen supply, In a hydrogen gas supply line connecting the steam electrolysis apparatus and the hydrogen supply target, a cooling step is performed in which the hydrogen gas is cooled using a cooler, In the hydrogen gas supply line, a dehumidification step is performed in which moisture is removed from the hydrogen gas flowing downstream of the cooler using a dehumidifier, A regeneration gas supply step involves supplying a regeneration gas to the dehumidifier in order to regenerate the adsorbent of the dehumidifier, A first heating step in which the regenerating gas is heated using the hydrogen gas flowing upstream of the cooler in the hydrogen gas supply line as a heat source, A hydrogen production method equipped with the following features.

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