Hydrogen supply system and hydrogen supply method

Abstract

To provide a system and method that contribute to effective use of hydrogen.SOLUTION: A hydrogen supply system 10 comprises a water electrolysis apparatus 12 configured to generate a hydrogen-containing gas, a main supply line 14 that sends at least a portion of the hydrogen-containing gas obtained by the water electrolysis apparatus 12 to a demand destination D, and a sub-supply line 16 that branches from the main supply line 14, is provided with a deoxidizer 23 and a dehydrator 24, and sends a hydrogen-containing gas other than the hydrogen-containing gas sent to the demand destination D among the hydrogen-containing gas obtained by the water electrolysis apparatus 12 to a fuel cell 18. The demand destination D comprises equipment that uses a hydrogen-containing gas containing hydrogen of lower purity than the hydrogen-containing gas used in the fuel cell 18.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hydrogen supply system and a hydrogen supply method. [Background technology]

[0002] In recent years, in consideration of the environment, the use of hydrogen as a fuel for power generation, automobiles, etc. has been considered, and the demand for hydrogen is increasing. For example, Patent Document 1 listed below discloses a hydrogen supply system including a water electrolyzer and a humidity control device for controlling the moisture content of the hydrogen-containing gas obtained by the water electrolyzer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-58168 Summary of the Invention [Problem to be solved by the invention]

[0004] In the hydrogen supply system disclosed in Patent Document 1, the moisture content of the hydrogen-containing gas is adjusted by a humidity control device to a moisture content that meets the requirements of the hydrogen utilization equipment, and the hydrogen with the adjusted moisture content is supplied to the hydrogen utilization equipment. Therefore, it can also be used with hydrogen utilization equipment that requires a hydrogen-containing gas containing high-purity hydrogen. However, because it can only supply hydrogen-containing gas to one hydrogen utilization equipment, it is not sufficiently convenient as a hydrogen supply system.

[0005] The present invention has been made in view of the above-mentioned prior art, and an object of the present invention is to contribute to the effective utilization of hydrogen. [Means for solving the problem]

[0006] To achieve the above object, a hydrogen supply system according to the present invention includes a water electrolysis device configured to generate a hydrogen-containing gas, a main supply line for sending at least a portion of the hydrogen-containing gas produced by the water electrolysis device to a consumer, and a sub-supply line branching from the main supply line and provided with a deoxidizer and a dehydrator, for sending the hydrogen-containing gas produced by the water electrolysis device other than the hydrogen-containing gas sent to the consumer to a fuel cell, the consumer having equipment that uses a hydrogen-containing gas containing hydrogen of lower purity than the hydrogen-containing gas used in the fuel cell.

[0007] In the hydrogen supply system according to the present invention, at least a portion of the hydrogen-containing gas produced by the water electrolysis device is supplied to a consumer, and the remaining portion of the hydrogen-containing gas is supplied to a fuel cell. Therefore, not only is hydrogen supplied to a consumer, but the fuel cell can also be used to generate electricity. This improves the convenience of the hydrogen supply system and contributes to the effective use of hydrogen. Furthermore, because the consumer connected to the main supply line uses a hydrogen-containing gas containing hydrogen of lower purity than the hydrogen-containing gas used in the fuel cell, there is no need to provide a deoxidizer or dehydrator in the main supply line. This prevents the system from becoming expensive. Furthermore, because the power generated by the fuel cell can be used by the water electrolysis device, the fuel cell can be used as an emergency power source or backup power source for the water electrolysis device. This stabilizes the operation of a system that supplies a hydrogen-containing gas containing low-purity hydrogen, or ensures safety during shutdowns. Furthermore, because the specifications of the ancillary equipment, such as the deoxidizer and dehydrator, only need to be tailored to the flow rate of the hydrogen-containing gas flowing through the secondary supply line, the ancillary equipment can be prevented from becoming large.

[0008] The main supply passage may be designed to deliver a flow rate of hydrogen-containing gas that is greater than the flow rate delivered by the secondary supply passage.

[0009] This embodiment can also accommodate cases where a large amount of hydrogen-containing gas is consumed at the demand side, and is therefore effective when the main supply line is connected to a demand side that has a large demand for hydrogen-containing gas.

[0010] The main supply channel and the sub-supply channel may each be provided with a flow rate adjustment valve. In this case, the flow rate adjustment valve of the main supply channel may be adjusted to an aperture size such that the hydrogen-containing gas is supplied to the demand destination at a flow rate corresponding to the amount required by the demand destination, and the flow rate adjustment valve of the sub-supply channel may be adjusted to an aperture size such that the remainder of the hydrogen-containing gas obtained by the water electrolysis device and supplied to the demand destination is supplied to the fuel cell.

[0011] In this aspect, at least a portion of the hydrogen-containing gas obtained by the water electrolysis device is adjusted by the flow rate control valve of the main supply line to a flow rate according to a demand from the demand destination, and then supplied to the demand destination. That is, meeting the demand from the demand destination is given priority. Furthermore, the remainder of the obtained hydrogen-containing gas can be used in the fuel cell, so that the hydrogen-containing gas obtained by the water electrolysis device can be effectively used.

[0012] The hydrogen supply system includes a return path for returning a portion of the hydrogen-containing gas obtained in the dehydration device to the dehydration device, and a connecting path for sending the hydrogen-containing gas that is returned to the dehydration device and used to regenerate the dehydration device to the main supply path, and the connecting path may be provided with a moisture removal device that cools the hydrogen-containing gas flowing through the connecting path and removes moisture from the hydrogen-containing gas.

[0013] In this embodiment, the dehydration device can be regenerated using the hydrogen-containing gas with high hydrogen purity discharged from the dehydration device. This allows for a longer life of the dehydration device. Furthermore, since the hydrogen-containing gas, which has been returned to the dehydration device and has a reduced hydrogen purity, is sent to a consumer through the main supply path, this hydrogen-containing gas can also be effectively utilized at the consumer. For example, heating furnaces, boilers, turbines, and the like are examples of consumer equipment that uses hydrogen-containing gas containing hydrogen with a lower purity than the hydrogen-containing gas used in fuel cells. These consumer equipment can use hydrogen-containing gas with a lower hydrogen purity, contributing to the effective utilization of hydrogen. Furthermore, the hydrogen-containing gas used to regenerate the dehydration device does not directly merge with the main supply path; instead, a moisture removal device disposed in the connecting path condenses and removes moisture from the gas, and the hydrogen-containing gas then merges with the main supply path. In other words, the hydrogen-containing gas used to regenerate the dehydration device contains more moisture than the gas produced by the water electrolysis device, and therefore has a higher moisture concentration. Therefore, if the hydrogen-containing gas used to regenerate the dehydration device is directly merged into the main supply line, there is a risk that the calorific value at the demand end, such as a heating furnace, will decrease. Therefore, by lowering the moisture concentration of the hydrogen-containing gas flowing through the connecting line using a moisture removal device, it is possible to suppress the decrease in calorific value due to heating and evaporation of moisture. In addition, because moisture is removed by cooling the hydrogen-containing gas and condensing the moisture, there is no need to regenerate the adsorbent.

[0014] The main supply line may be configured to be free of a dehydration device and to supply the hydrogen-containing gas obtained by the water electrolysis device to the demand destination without adjusting the hydrogen content. In this aspect, the cost of the hydrogen supply system can be reduced.

[0015] The hydrogen supply method according to the present invention includes a hydrogen generation step of generating a hydrogen-containing gas using a water electrolysis device, a main supply step of sending at least a portion of the hydrogen-containing gas produced by the water electrolysis device to a consumer through a main supply path, and a sub-supply step of treating the hydrogen-containing gas produced by the water electrolysis device other than the hydrogen-containing gas to be sent to the consumer in a deoxidizer and a dehydrator to increase the hydrogen purity, and then sending the hydrogen-containing gas to a fuel cell through a sub-supply path. In the main supply step, a hydrogen-containing gas containing hydrogen of lower purity than the hydrogen-containing gas used in the fuel cell is sent to the consumer.

[0016] In the main supply step, the hydrogen-containing gas may be sent to the demand destination at a flow rate greater than the flow rate of the hydrogen-containing gas supplied to the fuel cell in the sub-supply step.

[0017] When a flow rate control valve is provided in each of the main supply path and the sub-supply path, the aperture of the flow rate control valve of the main supply path may be adjusted in the main supply step so that the hydrogen-containing gas is supplied to the demand destination at a flow rate according to a request from the demand destination, and the aperture of the flow rate control valve of the sub-supply path may be adjusted in the sub-supply step so that the remainder of the hydrogen-containing gas obtained by the water electrolysis device and supplied to the demand destination is supplied to the fuel cell.

[0018] The hydrogen supply method may further include a regeneration step of returning a portion of the hydrogen-containing gas obtained in the dehydration device to the dehydration device to regenerate the dehydration device, and a reuse step of sending the hydrogen-containing gas used in the regeneration of the dehydration device to the main supply line. [Effects of the Invention]

[0019] As described above, the present invention can contribute to the effective use of hydrogen. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram illustrating a schematic configuration of a hydrogen supply system according to an embodiment. [Figure 2]3 is a diagram illustrating a hydrogen supply method using the hydrogen supply system. FIG. [Figure 3] FIG. 10 is a diagram for explaining the operation when operation is stopped when a power supply abnormality occurs. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0022] As shown in FIG. 1 , a hydrogen supply system 10 according to this embodiment is a system for supplying hydrogen-containing gas generated in a water electrolysis apparatus 12 to a hydrogen demand destination D. Examples of hydrogen demand destinations D include demand destinations D having equipment that constantly requires a large amount of hydrogen-containing gas, such as a heating furnace for heating steel materials or the like, or a boiler installed in a power generation plant. Note that these facilities do not require a hydrogen-containing gas with as high a purity as a fuel cell 18, which will be described later. In other words, these facilities use a hydrogen-containing gas with a lower purity (higher water content) than the hydrogen-containing gas used in the fuel cell 18. Other demand destinations D having such equipment include methanation plants and gas cultivation plants.

[0023] The hydrogen supply system 10 includes a water electrolysis device 12, a main supply line 14, and a sub-supply line 16. The water electrolysis device 12 is a device that electrolyzes water to generate hydrogen-containing gas, and electrolyzes water using power obtained, for example, from a power generation mechanism using renewable energy or biomass, grid power, or a storage battery, or a combination thereof. Examples of renewable energy include solar light, wind power, hydropower, wave power, tidal power, geothermal energy, solar heat, atmospheric heat, and other heat present in nature.

[0024] The main supply line 14 connects the water electrolysis device 12 and the demand destination D to each other, and is configured so that at least a portion of the hydrogen-containing gas obtained in the water electrolysis device 12 can be sent to the demand destination D.

[0025] The main supply path 14 is provided with a flow rate adjustment valve (first adjustment valve 21) for adjusting the flow rate of the hydrogen-containing gas flowing through the main supply path 14. In this embodiment, the opening degree of the first adjustment valve 21 is set by an operator so as to obtain a flow rate corresponding to the amount requested by the demand destination D. The opening degree of the first adjustment valve 21 may be controlled by a controller 26 described below. In this case, the controller 26 may be configured to control the opening degree of the first adjustment valve 21 in accordance with a signal indicating the amount of gas demand sent from the demand destination D at predetermined time intervals so as to obtain a flow rate corresponding to the requested amount.

[0026] The sub-supply path 16 branches off from the main supply path 14 and is connected to the fuel cell 18. That is, the sub-supply path 16 is configured to send the hydrogen-containing gas obtained in the water electrolysis device 12, other than the hydrogen-containing gas sent to the demand destination D, to the fuel cell 18.

[0027] The hydrogen-containing gas flows through the sub-supply channel 16 at a flow rate that is smaller than the flow rate of the hydrogen-containing gas flowing through the main supply channel 14. For this reason, the main supply channel 14 is designed to send the hydrogen-containing gas at a flow rate that is larger than the flow rate through the sub-supply channel 16. In other words, the hydrogen supply system 10 is designed to supply a small amount or surplus hydrogen-containing gas to the fuel cell 18, on the premise that the hydrogen-containing gas is supplied to a demand destination D that consumes a large amount of hydrogen-containing gas. For this reason, the hydrogen supply system 10 is designed so that most (at least 50% or more) of the hydrogen-containing gas obtained in the water electrolysis device 12 is sent to the demand destination D through the main supply channel 14. Therefore, the piping that constitutes the sub-supply channel 16 is made of tubing members with a smaller diameter than the piping that constitutes the main supply channel 14.

[0028] The sub-supply channel 16 is provided with a deoxygenator 23 and a dehydrator 24. That is, in the sub-supply channel 16, oxygen and moisture are removed from the hydrogen-containing gas obtained in the water electrolysis device 12, thereby increasing the purity of hydrogen in the hydrogen-containing gas to a level that can be used for power generation by the fuel cell 18.

[0029] The fuel cell 18 provides at least a portion of the power required by the hydrogen supply system 10, and can supply power to a controller 26, various pumps 27, a ventilation fan 28, and the like provided in the hydrogen supply system 10. An example of the controller 26 is a controller that includes a control unit that performs overall control of the operation of the hydrogen supply system 10 and a control unit that controls the water electrolysis device 12. The various pumps 27 include, for example, a pump for supplying water as a raw material to the water electrolysis device 12, a pump for supplying cooling water to cool the water electrolysis device 12, and the like. An example of the ventilation fan 28 is a ventilation fan for ventilating a room that is at risk of being filled with hydrogen, such as a room in which the water electrolysis device 12 is installed.

[0030] The power obtained by the fuel cell 18 may be stored in preparation for an emergency shutdown. That is, to safely shut down the water electrolysis device 12, it is necessary to cool the electrolysis module in the water electrolysis device 12, purge oxygen from the electrolysis module, supply nitrogen for purging hydrogen from the sub-supply channel 16, operate the ventilation fan 28, and so on. Therefore, the power obtained by the fuel cell 18 may be constantly secured as the power required for these operations. Note that if the power required during shutdown can be generated by the normal operation of the fuel cell 18 without storing the power, a storage battery is not essential.

[0031] The sub-supply path 16 is provided with a flow rate adjustment valve (second adjustment valve 31) for adjusting the flow rate of the hydrogen-containing gas flowing through the sub-supply path 16. In this embodiment, the aperture of the second adjustment valve 31 is set by an operator so as to obtain a flow rate obtained by subtracting the amount of hydrogen-containing gas required by the demand destination D from the amount of hydrogen-containing gas generated in the water electrolysis apparatus 12. A flow meter 32 is provided in the sub-supply path 16, and the operator can adjust the aperture of the second adjustment valve 31 while referring to the measurement value of the flow meter 32.

[0032] The second adjusting valve 31 may be configured so that its opening degree is controlled by the controller 26. In this case, the controller 26 is configured to control the opening degree of the second adjusting valve 31 of the sub-supply path 16 in accordance with the control of the opening degree of the first adjusting valve 21 of the main supply path 14.

[0033] A reflux path 34 is connected to the sub-supply path 16, which refluxes a portion of the hydrogen-containing gas obtained in the dehydration device 24 back to the dehydration device 24. That is, the dehydration device 24 contains a moisture adsorbent so that moisture in the hydrogen-containing gas can be removed to increase the purity of hydrogen contained in the hydrogen-containing gas. The adsorbent reduces the amount of moisture adsorbed with continued use, so it must be regenerated periodically. For this reason, a portion of the hydrogen-containing gas whose hydrogen purity has been increased by the dehydration device 24 is returned to the dehydration device 24 through the reflux path 34, and the moisture adsorbed in the adsorbent is released from the adsorbent.

[0034] The moisture released from the adsorbent flows through the connecting path 35, entrained with the hydrogen-containing gas. The connecting path 35 connects the dehydrator 24 to a portion of the main supply path 14 downstream of the connection point with the sub-supply path 16. The connecting path 35 allows the hydrogen-containing gas containing moisture released from the dehydrator 24 to flow into the main supply path 14. That is, at a demand destination D having equipment such as a heating furnace, a boiler, a turbine, or the like, a hydrogen-containing gas with a low hydrogen purity can be used, and therefore even the hydrogen-containing gas used to regenerate the adsorbent in the dehydrator 24 can be effectively utilized. Note that the connecting path 35 may be configured not to be connected to the main supply path 14, but to exhaust the hydrogen-containing gas to the atmosphere.

[0035] The connection path 35 may be provided with a moisture remover 37 that cools the hydrogen-containing gas used to regenerate the dehydrator 24 and removes moisture from the gas. The moisture-containing hydrogen-containing gas released from the dehydrator 24 contains a large amount of moisture that was adsorbed to the adsorbent in the dehydrator 24, and therefore has a higher moisture concentration than the hydrogen-containing gas produced by electrolysis in the water electrolysis device 12. Therefore, if the hydrogen-containing gas is directly flowed through the connection path 35 to the main supply path 14, there is a concern that the calorific value may be somewhat reduced due to heating and evaporation of the entrained moisture during combustion at the demand destination D, depending on the relationship with the flow rate of the hydrogen-containing gas from the main supply path 14. For this reason, before the hydrogen-containing gas flowing through the connection path 35 is merged with the gas flowing through the main supply path 14, the hydrogen-containing gas flowing through the connection path 35 may be cooled by the moisture remover 37 to remove moisture from the hydrogen-containing gas (condensing the moisture entrained in the gas to separate the gas components from the liquefied moisture and discharging the liquefied moisture separately from the gas components). This makes it possible to suppress a decrease in the calorific value during combustion at the demand destination D.

[0036] The moisture removal device 37 does not use an adsorbent to remove moisture from the gas like the dehydration device 24, but is structured to condense only the moisture in the gas by cooling the gas, separate the gas components from the liquefied moisture, and collect and discharge the liquefied moisture. By providing a moisture removal device 37 with this structure, it is possible to efficiently separate the gas components from the liquefied moisture without using an adsorbent, and discharge the liquefied moisture separately from the gas components. Because no adsorbent is used, there is no need for a regeneration process for the adsorbent. Although the moisture in the hydrogen-containing gas cannot be reduced as much as the dehydration device 24, it is possible to suppress a decrease in the heat generation value when the hydrogen-containing gas is used for combustion.

[0037] An on-off valve 35a is provided in the connection line 35, and a discharge line 36 is connected to a location upstream of the on-off valve 35a. An on-off valve 36a is also provided in the discharge line 36. Therefore, by opening and closing these on-off valves 35a, 36a, it is possible to select whether the hydrogen-containing gas is to be used or discarded.

[0038] The main supply path 14 is provided with a pressure detector 38 for monitoring the pressure of the hydrogen-containing gas. In Fig. 1, the pressure detector 38 is configured as a sensor provided in the main supply path 14 at a position upstream of the connection point with the sub-supply path 16. Alternatively, the pressure detector 38 may be configured with a pressure sensor provided in the main supply path 14 at a position downstream of the connection point with the sub-supply path 16, and a pressure sensor provided in the sub-supply path 16. This is effective when the pressures of the hydrogen-containing gas required by the demand destination D and the fuel cell 18 differ. In this case, not only a pressure sensor but also a pressure regulating valve may be provided.

[0039] An oxygen flow path 40 for processing the oxygen obtained by the water electrolysis device 12 is connected to the water electrolysis device 12. The oxygen flow path 40 may be connected to the main supply line 14 to supply the oxygen as a combustion improver to a boiler, a heating furnace, or a turbine. The oxygen flow path 40 may also be configured to release oxygen into the atmosphere.

[0040] Here, a hydrogen supply method using the hydrogen supply system 10 according to this embodiment will be described. Fig. 2 shows operation during normal operation, and during normal operation, the hydrogen supply method includes a step of generating a hydrogen-containing gas using the water electrolysis device 12 (hydrogen generation step ST11). That is, the water electrolysis device 12 electrolyzes water as a raw material to generate a hydrogen-containing gas. At least a portion of the obtained hydrogen-containing gas is sent to the demand destination D through the main supply path 14 (main supply step ST12). At this time, the aperture of the first adjustment valve 21 of the main supply path 14 is set so as to obtain a flow rate corresponding to the amount required by the demand destination D, and therefore the hydrogen-containing gas is sent to the demand destination D through the main supply path 14 at a flow rate corresponding to the amount required, and is consumed by the demand destination D.

[0041] That is, since the main supply path 14 is not provided with the deoxygenator 23 or the dehydrator 24, in the main supply step, a hydrogen-containing gas containing hydrogen of lower purity than the hydrogen-containing gas used in the fuel cell 18 is supplied to the demand destination D. Also, in the main supply path 14, the hydrogen-containing gas flows at a flow rate greater than the flow rate of the hydrogen-containing gas flowing in the sub-supply path 16.

[0042] Furthermore, the hydrogen-containing gas obtained in the water electrolysis device 12 other than the hydrogen-containing gas sent to the demand destination D flows through the sub-supply path 16 and is sent to the fuel cell 18 (sub-supply step ST13). In the sub-supply path 16, the hydrogen-containing gas is processed in the deoxygenator 23 and the dehydrator 24 to increase the hydrogen purity, and the hydrogen purity becomes suitable for power generation in the fuel cell 18.

[0043] This high-purity hydrogen-containing gas is supplied to the fuel cell 18. The hydrogen-containing gas sent to the fuel cell 18 is converted into electricity in the fuel cell 18. This electricity may be used to operate the electrical system of the hydrogen supply system 10, or may be supplied to an external device. The electricity required to operate the electrical system of the hydrogen supply system 10 is 100 Nm 3 If a hydrogen generation rate of about 1000 kJ / h can be achieved, then about 3% of that amount of hydrogen is considered sufficient.

[0044] In the secondary supply process, the opening degree of the second adjustment valve 31 of the secondary supply path 16 is adjusted so that the remaining portion of the hydrogen-containing gas obtained by the water electrolysis device 12 and supplied to the demand destination D is supplied to the fuel cell 18.

[0045] That is, the hydrogen generated in the water electrolysis device 12 (HHOG) is branched into two lines, one of which flows to a combustion line and the other to a line where it is purified for the fuel cell 18. The distribution at this time is adjusted so that the majority of the hydrogen flows to the combustion line and a portion is supplied to the fuel cell 18. In other words, since fuel applications require a certain amount of combustion, such as in heating furnaces, boilers, and turbines, this is usually given priority. However, if a certain amount is required for the fuel cell 18, the flow distribution can be adjusted to increase the hydrogen flow rate to the fuel cell 18 side.

[0046] A portion of the hydrogen-containing gas that has flowed through the sub-supply path 16 and has had its hydrogen purity increased by the dehydrator 24 is returned to the dehydrator 24 through the return path 34 and is used to regenerate the dehydrator 24 (regeneration step ST14). The hydrogen-containing gas used to regenerate the dehydrator 24 flows into the main supply path 14 through the connection path 35 and is used at the demand destination D (reuse step ST15). This reuse step ST15 includes a moisture separation step in which the hydrogen-containing gas used to regenerate the dehydrator 24 is cooled in the moisture remover 37 of the connection path 35 to condense moisture entrained in the gas and separate it from the gas components.

[0047] The oxygen generated in the water electrolysis device 12 is extracted through the oxygen flow path 40 and sent to a demand destination D (a heating furnace, a boiler, or a turbine) for use as auxiliary fuel for combustion. The oxygen may be stored in a tank (not shown) provided in the oxygen flow path 40. The oxygen stored in the tank may be supplied as a starter to a heating furnace, a boiler, or the like when the hydrogen supply system 10 is started up.

[0048] Next, with reference to FIG. 3, the operation when operation is stopped due to the occurrence of a power supply abnormality such as a power outage will be described.

[0049] When shutting down, operation control is performed with priority given to safely shutting down the hydrogen supply system 10. To safely shut down the system 10, it is necessary to cool the electrolysis module of the water electrolysis device 12, purge oxygen in the electrolysis module with nitrogen or the like, purge hydrogen remaining in the piping and the like with nitrogen or the like, and continue operating the ventilation fan 28 for a certain period of time. Specifically, these measures are carried out using power generated by the fuel cell 18 as described below, and once these measures have been sufficiently completed, the water electrolysis device 12 is shut down and the power supply to the hydrogen supply system 10 is stopped.

[0050] First, the first adjustment valve 21 provided on the main supply path 14 through which the hydrogen-containing gas flows from the water electrolysis device 12 to the demand destination D is closed (step ST21). As a result, all of the hydrogen-containing gas produced by the water electrolysis device 12 flows to the fuel cell 18. This hydrogen-containing gas is used to generate electricity in the fuel cell 18 (step ST22), and this electricity is used to cover the power required to operate the water electrolysis device 12. The operation of the water electrolysis device 12 is continued while monitoring the temperature of the electrolysis module, and is continued until the temperature reaches a level at which it can be determined that the electrolysis module has been cooled to a predetermined temperature, or for a certain period of time required for the electrolysis module to be cooled. Then, when a predetermined condition is met, the operation of the water electrolysis device 12 is stopped (step ST23).

[0051] Here, an example of the flow rate of the hydrogen-containing gas and the amount of power generated during normal operation will be introduced. 3 / h, and hydrogen-containing gas (3Nm 3 / h) is supplied to the fuel cell 18, the fuel cell 18 can generate approximately 5 kW of electricity. This power can cover the power of the various pumps 27 and the ventilation fan 28. In other words, during normal operation, at least 2 Nm 3 Approximately 1000 kJ / h of hydrogen-containing gas (high-purity hydrogen-containing gas after passing through the dehydration device 24) is always present in the sub-supply line 16.

[0052] Furthermore, when operation is stopped due to a power outage or other power supply abnormality, approximately 20 minutes of operation is required to safely stop the operation using electricity obtained from the fuel cell 18, so to operate for a longer period of time, i.e., 30 minutes, approximately 2.5 kWh (= 5 kW × 0.5 hr) of power is required. For example, the capacity of a typical fuel cell is approximately 0.67 Nm of hydrogen to generate 1 kW of electricity. 3 / h is required. Therefore, 0.67Nm 3 / h×2.5kWh=1.68Nm 3 Therefore, the total volume of the sub-supply channel 16 and the tanks attached to the fuel cell 18 is 1.68 Nm 3 By ensuring the above internal volume, the power obtained from the fuel cell 18 can cover the power required to cool the water electrolysis module, the power required to purge oxygen from within the electrolysis module, the power required to power the ventilation fan 28, and the power required for the controller 26. Although an example in which the required amount of hydrogen is stored within the system has been described, the present invention is not limited to this. Since the objective is to secure the amount of electricity required for scheduled operation, the amount of hydrogen stored within the system may be minimized, and the required amount of electricity generated by the fuel cell 18 may be stored in a separate storage battery for use in the event of a power supply abnormality.

[0053] As described above, according to this embodiment, at least a portion of the hydrogen-containing gas produced by the water electrolysis apparatus 12 is supplied to the demand destination D, and the remaining portion of the hydrogen-containing gas is supplied to the fuel cell 18. Therefore, not only is hydrogen supplied to the hydrogen demand destination D, but also the fuel cell 18 can be used to generate electric power. This improves the convenience of the hydrogen supply system 10 and contributes to the effective use of hydrogen. Furthermore, because the demand destination D connected to the main supply line 14 uses a hydrogen-containing gas containing hydrogen of lower purity than the hydrogen-containing gas used in the fuel cell 18, the main supply line 14 does not need to be provided with the deoxidizer 23 and the dehydrator 24. This prevents the system from becoming expensive. Furthermore, because the electric power generated by the fuel cell 18 can be used by the water electrolysis apparatus 12, the fuel cell 18 can be used as an emergency power source or backup power source for the water electrolysis apparatus 12. This contributes to stabilizing the operation of a system that supplies hydrogen-containing gas containing low-purity hydrogen, or ensuring safety during shutdown. Furthermore, the specifications of the ancillary equipment such as the deoxidizer 23 and the dehydrator 24 can be set according to the flow rate of the hydrogen-containing gas flowing through the sub-supply passage 16, so that the ancillary equipment can be prevented from becoming large in size.

[0054] Furthermore, in this embodiment, the main supply path 14 is designed to send the hydrogen-containing gas at a flow rate greater than the flow rate through the sub-supply path 16. This allows for a case where a large amount of hydrogen-containing gas is consumed at the demand destination D. Therefore, this is effective when the main supply path 14 is connected to a demand destination D that has a large demand for hydrogen-containing gas.

[0055] Furthermore, in this embodiment, the opening degree of the first regulating valve 21 is adjusted so that the hydrogen-containing gas is supplied to the demand destination D at a flow rate corresponding to the amount requested by the demand destination D, and the opening degree of the second regulating valve 31 is adjusted so that the remainder of the hydrogen-containing gas obtained by the water electrolysis apparatus 12 and supplied to the demand destination D is supplied to the fuel cell 18. That is, when allocating the hydrogen-containing gas obtained by the water electrolysis apparatus 12, priority is given to meeting the amount requested by the demand destination D. The remainder of the obtained hydrogen-containing gas is then used in the fuel cell 18. As a result, the hydrogen-containing gas obtained by the water electrolysis apparatus 12 can be effectively used at the demand destination D, enabling efficient recovery / supply of hydrogen gas.

[0056] Furthermore, in this embodiment, the dehydrator 24 is regenerated by the hydrogen-containing gas with high hydrogen purity discharged from the dehydrator 24. This allows the life of the dehydrator 24 to be extended. Moreover, the hydrogen-containing gas with reduced hydrogen purity that has been returned to the dehydrator 24 through the return path 34 is sent to the demand destination D, so this hydrogen-containing gas can also be effectively utilized. For example, examples of demand destinations D that have equipment that uses a hydrogen-containing gas containing hydrogen with lower purity than the hydrogen-containing gas used in the fuel cell 18 include heating furnaces, boilers, turbines, etc., and these demand destinations D can use hydrogen-containing gas with lower hydrogen purity, which contributes to effective utilization of hydrogen.

[0057] Furthermore, in this embodiment, the dehydration device 24 is not provided in the main supply path 14, so that the cost of the hydrogen supply system 10 can be reduced.

[0058] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The present invention is not limited to the above-described embodiments, and various modifications and improvements are possible without departing from the spirit of the present invention. For example, in the above-described embodiments, the main supply path 14 is designed to deliver hydrogen-containing gas at a flow rate greater than the flow rate through the sub-supply path 16, but the present invention is not limited to this. When hydrogen-containing gas is supplied to a demand destination D that does not have equipment that consumes large amounts of hydrogen-containing gas, the main supply path 14 and the sub-supply path 16 may be designed to deliver hydrogen-containing gas at approximately the same flow rate, or the main supply path 14 may be designed to deliver hydrogen-containing gas at a flow rate smaller than that through the sub-supply path 16.

[0059] In the above embodiment, when the hydrogen-containing gas obtained in the water electrolysis device 12 is distributed between the demand destination D and the fuel cell 18, the apertures of the first regulating valve 21 and the second regulating valve 31 are adjusted so that the demand destination D is given priority during normal operation, but this is not limiting. The apertures of the first regulating valve 21 and the second regulating valve 31 may be adjusted so that the demand destination D is not given priority during normal operation, or it may be possible to perform normal operation in which the demand destination D is given priority, and also to perform operation in which the demand destination D is not given priority (operation in which supply to the fuel cell 18 is given priority) separately from the normal operation.

[0060] In the above embodiment, a portion of the high-purity hydrogen-containing gas obtained in the dehydrator 24 is used for regenerating the dehydrator 24, but the present invention is not limited to this. A separate hydrogen supply source for regenerating the dehydrator 24 may be provided. In this case, the hydrogen used for regenerating the dehydrator 24 may be discharged as is or may be introduced into the main supply line 14. [Explanation of symbols]

[0061] 10: Hydrogen supply system 12:Water electrolysis device 14: Main supply route 16: Sub-supply route 18: Fuel cell 21: First adjusting valve (flow adjusting valve) 23: Deoxygenation device 24: Dehydration equipment 31: Second adjusting valve (flow adjusting valve) 34: Reflux channel 35: Connection road 37: Moisture removal device D: Demand destination ST11: Hydrogen generation process ST12: Main supply process ST13: Sub-supply process ST14: Regeneration process ST15: Reuse process

Claims

1. a water electrolysis device configured to generate a hydrogen-containing gas; a main supply line for sending at least a portion of the hydrogen-containing gas obtained by the water electrolysis apparatus to a consumer; a sub-supply line branching from the main supply line and provided with a deoxidizer and a dehydrator, for supplying to a fuel cell the hydrogen-containing gas obtained by the water electrolysis device other than the hydrogen-containing gas to be supplied to the consumer; Equipped with The demand destination is a hydrogen supply system having a facility that uses a hydrogen-containing gas containing hydrogen of lower purity than the hydrogen-containing gas used in the fuel cell.

2. 2. The hydrogen supply system of claim 1, wherein the main supply channel is designed to deliver a hydrogen-containing gas at a flow rate greater than the flow rate delivered by the secondary supply channel.

3. a flow rate adjustment valve is provided in each of the main supply path and the sub-supply path; the flow rate regulating valve of the main supply line is adjusted to an opening degree so that the hydrogen-containing gas is supplied to the demand destination at a flow rate corresponding to the amount required by the demand destination, 2. The hydrogen supply system according to claim 1, wherein the flow rate control valve of the sub-supply line is adjusted to an opening degree such that the remainder of the hydrogen-containing gas obtained by the water electrolysis device and supplied to the demand destination is supplied to the fuel cell.

4. a reflux path for refluxing a portion of the hydrogen-containing gas obtained in the dehydration device to the dehydration device; a connecting line for sending the hydrogen-containing gas that is returned to the dehydration device and used for regenerating the dehydration device to the main supply line, 2. The hydrogen supply system according to claim 1, wherein the connecting passage is provided with a moisture removal device that cools the hydrogen-containing gas flowing through the connecting passage and removes moisture from the hydrogen-containing gas.

5. 2. The hydrogen supply system according to claim 1, wherein the main supply line is not provided with a dehydration device, and the main supply line is configured to supply the hydrogen-containing gas obtained by the water electrolysis device to the demand destination without adjusting the hydrogen content.

6. a hydrogen generating step of generating a hydrogen-containing gas using a water electrolysis device; a main supply step of sending at least a portion of the hydrogen-containing gas obtained by the water electrolysis apparatus to a consumer through a main supply path; a sub-supply step of treating the hydrogen-containing gas obtained by the water electrolysis device other than the hydrogen-containing gas to be sent to the consumer in a deoxidizer and a dehydrator to increase the hydrogen purity, and sending the treated hydrogen-containing gas to the fuel cell through a sub-supply path; Including, In the main supply step, a hydrogen-containing gas containing hydrogen of lower purity than the hydrogen-containing gas used in the fuel cell is sent to the demander.

7. 7. The hydrogen supply method according to claim 6, wherein in the main supply step, the hydrogen-containing gas is sent to the demand destination at a flow rate greater than the flow rate of the hydrogen-containing gas supplied to the fuel cell in the sub-supply step.

8. a flow rate adjustment valve is provided in each of the main supply path and the sub-supply path; In the main supply step, the opening degree of the flow rate control valve of the main supply line is adjusted so that the hydrogen-containing gas is supplied to the demand destination at a flow rate according to a request from the demand destination, 7. The hydrogen supply method according to claim 6, wherein in the sub-supply step, an aperture of the flow rate control valve of the sub-supply path is adjusted so that the remainder of the hydrogen-containing gas obtained by the water electrolysis device and supplied to the demand destination is supplied to the fuel cell.

9. a regeneration step of regenerating the dehydration device by refluxing a portion of the hydrogen-containing gas obtained in the dehydration device to the dehydration device; 7. The hydrogen supply method according to claim 6, further comprising a recycling step of sending the hydrogen-containing gas used in regenerating the dehydration device to the main supply line.

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