Leak detection method, leak detection device, and hydrogen production equipment

Abstract

To properly detect electrolyte leakage from water electrolysis equipment while reducing costs. [Solution] A method for detecting leakage of electrolyte from a water electrolysis apparatus, wherein the water electrolysis apparatus includes an electrolytic cell for storing electrolyte, a gas-liquid separator through which the gas generated in the electrolytic cell is introduced, and a circulation line for circulating the electrolyte between the electrolytic cell and the gas-liquid separator, and comprises the steps of: obtaining an integrated estimated value which is the cumulative value of the estimated amount of pure water supplied to the electrolyte from a reference point; obtaining an integrated measured value which is the cumulative value of the measured amount of pure water supplied to the electrolyte from the reference point; and detecting leakage of the electrolyte from the water electrolysis apparatus based on a comparison between a threshold value determined based on the integrated estimated value and the integrated measured value.

Description

Technical Field

[0001] The present disclosure relates to a leakage detection method, a leakage detection device, and a hydrogen production facility.

Background Art

[0002] As the electrolytic solution used in water electrolysis apparatuses for hydrogen production, substances that may adversely affect equipment (such as powerful drugs) may be used. Accordingly, it is required to appropriately detect leakage of the electrolytic solution from the water electrolysis apparatus.

[0003] Patent Document 1 describes an electrolysis apparatus provided with a sensor for detecting liquid leakage from an electrolytic cell. In this electrolysis apparatus, when liquid leakage is detected by the sensor, the control unit shuts off the inflow of liquid to the electrolytic cell. This suppresses the pressure rise in the electrolytic cell and further liquid leakage caused by the progress of liquid electrolysis.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] It is considered that leakage of the electrolytic solution from the electrolysis apparatus can be reliably detected by using a liquid leakage sensor as described in Patent Document 1. However, as the apparatus becomes larger, the number of locations where leakage may occur increases, so that a large number of liquid leakage sensors need to be installed to reliably detect the leakage of the electrolytic solution, which increases the cost.

[0006] In view of the above circumstances, at least one embodiment of the present invention aims to provide a leakage detection method, a leakage detection device, and a hydrogen production facility capable of appropriately detecting leakage of an electrolytic solution from a water electrolysis apparatus while reducing costs. [Means for solving the problem]

[0007] A leak detection method according to at least one embodiment of the present invention is: A method for detecting electrolyte leakage from a water electrolysis device, The aforementioned water electrolysis apparatus is An electrolytic cell for storing electrolyte, A gas-liquid separator through which the gas generated in the electrolytic cell is introduced, The electrolytic cell and the gas-liquid separator include a circulation line for circulating the electrolyte between them, The steps include obtaining an integrated estimated value, which is the cumulative value from a reference point of the estimated amount of pure water supplied to the electrolyte according to the operating state of the water electrolysis apparatus, The steps include obtaining an integrated measurement value, which is the cumulative value of the measured amount of pure water supplied to the electrolyte from the reference point, A leak detection step that detects leakage of the electrolyte from the water electrolysis device based on a comparison between a threshold determined based on the cumulative estimated value and the cumulative measured value, It is equipped with.

[0008] Furthermore, the leak detection device according to at least one embodiment of the present invention is A leak detection device for detecting electrolyte leakage from a water electrolysis apparatus, A cumulative estimated value acquisition unit acquires a cumulative estimated value which is the cumulative value from a reference point of the estimated amount of pure water supplied to the electrolyte according to the operating state of the water electrolysis apparatus, A unit for acquiring cumulative measurement values, which is the cumulative value of the measured amount of pure water supplied to the electrolyte from the reference point, A leak detection unit detects leakage of the electrolyte from the water electrolysis device based on a comparison between a threshold value determined based on the cumulative estimated value and the cumulative measured value. It is equipped with.

[0009] Furthermore, the hydrogen production equipment according to at least one embodiment of the present invention is An electrolytic cell for storing electrolyte, A gas-liquid separator through which the gas generated in the electrolytic cell is introduced, a circulation line for circulating the electrolyte between the electrolytic cell and the gas-liquid separator, a water electrolysis apparatus including the leak detection apparatus according to the above [7], configured to detect leakage of the electrolyte from the water electrolysis apparatus, is provided. [Effects of the Invention]

[0010] According to at least one embodiment of the present invention, an object of the present invention is to provide a leak detection method, a leak detection apparatus, and a hydrogen production facility capable of appropriately detecting leakage of electrolyte from a water electrolysis apparatus while reducing costs. [Brief Description of the Drawings]

[0011] [Figure 1] It is a schematic configuration diagram of a hydrogen production facility according to an embodiment. [Figure 2] It is a schematic configuration diagram of a leak detection apparatus according to an embodiment. [Figure 3] It is a block diagram showing the configuration of a leak detection apparatus according to an embodiment. [Figure 4] It is a block diagram showing the configuration of a leak detection apparatus according to an embodiment. [Figure 5] It is a block diagram showing the configuration of a leak detection apparatus according to an embodiment. [Figure 6] It is a block diagram showing the configuration of a leak detection apparatus according to an embodiment. [Figure 7] It is a diagram for explaining a leak detection method according to an embodiment. [Modes for Carrying Out the Invention]

[0012] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, and are merely illustrative examples.

[0013] (Configuration of Hydrogen Production Facility) Figure 1 is a schematic configuration diagram of a hydrogen production facility according to an embodiment. As shown in Figure 1, a hydrogen production facility 1 according to some embodiments includes a water electrolysis device 2 for performing water electrolysis using an electrolytic solution, and a leak detection device 100 for detecting leakage of the electrolytic solution in the water electrolysis device 2.

[0014] The water electrolysis device 2 includes an electrolytic cell 4 in which an electrolytic solution is stored and for electrolyzing water, a cathode-side gas-liquid separator 16 and an anode-side gas-liquid separator 36 to which hydrogen gas and oxygen gas generated in the electrolytic cell 4 are respectively guided, and circulation lines 10, 30 for circulating the electrolytic solution between the electrolytic cell 4 and the gas-liquid separators 16, 36.

[0015] The illustrated water electrolysis device 2 includes a rectifier 8 for supplying DC power to the electrolytic cell 4. The rectifier 8 may be configured to convert power from a power source (power system or the like; not shown) from AC power to DC power as necessary, and output the converted power to the electrolytic cell 4 as a DC voltage. By applying a DC voltage between the electrodes of the electrolytic cell 4 via the rectifier 8, water contained in the electrolytic solution in the electrolytic cell 4 is electrolyzed, hydrogen gas is generated on the cathode side, and oxygen gas is generated on the anode side. The electrolytic solution is water in which an electrolyte is dissolved. The electrolyte contained in the electrolytic solution may be an alkaline substance such as potassium hydroxide (KOH).

[0016] To the gas-liquid separators 16, 36, hydrogen gas and oxygen gas discharged together with the electrolytic solution from the electrolytic cell 4 are introduced in the form of a gas-liquid two-phase flow via the outlet lines 12, 32 of the circulation lines 10, 30. In the gas-liquid separators 16, 36, the two-phase flow is separated into gas (hydrogen gas or oxygen gas) and liquid (electrolytic solution).

[0017] The gas (hydrogen gas or oxygen gas) separated from the two-phase flow in the gas-liquid separators 16, 36 is discharged from the gas-liquid separators 16, 36 via the gas discharge lines 18, 38. The hydrogen gas or oxygen gas discharged from the gas discharge lines 18, 38 may be supplied to a hydrogen consumption facility (for example, a gas turbine) or an oxygen consumption facility.

[0018] The electrolyte separated from the two-phase flow of electrolyte and gas in the gas-liquid separators 16 and 36 is returned to the electrolytic cell 4 via the inlet lines 14 and 34 of the circulation lines 10 and 30.

[0019] The circulation lines 10 and 30 may each be provided with circulation pumps 22 and 42 for circulating the electrolyte through the circulation lines 10 and 30. The circulation pumps 22 and 42 may be configured to be driven by motors (not shown). As shown, the circulation pumps 22 and 42 may be provided in the inlet lines 14 and 34 of the circulation lines 10 and 30, respectively.

[0020] Coolers 20 and 40 may be provided in the circulation lines 10 and 30, respectively, for cooling the electrolyte flowing through the circulation lines 10 and 30. Coolers 20 and 40 may be configured to cool the electrolyte flowing through the circulation lines 10 and 30 by heat exchange with a cooling medium. As shown in the figure, coolers 20 and 40 may be provided in the inlet lines 14 and 34 of the circulation lines 10 and 30, respectively.

[0021] As shown in Figure 1, the hydrogen production facility 1 is equipped with a pure water supply unit 50 to replenish the water electrolyzer 2 with water (pure water) for electrolysis. The pure water supply unit 50 is configured to supply pure water to the electrolyte in the water electrolyzer 2 in order to replenish the water consumed in the water electrolyzer 2 by electrolysis, evaporation, etc. The pure water supply unit 50 may also be configured to supply pure water to the inside of the equipment (electrolytic cell 4, gas-liquid separators 16, 36, or circulation lines 10, 30) through which the electrolyte flows in the water electrolyzer 2. In the illustrated exemplary embodiment, the pure water supply unit 50 is configured to supply pure water to the inside of the gas-liquid separator 16 on the cathode side.

[0022] In the exemplary embodiment shown in Figure 1, the pure water supply unit 50 includes a pure water line 52 connected to the equipment constituting the water electrolysis apparatus 2 (gas-liquid separator 16 in Figure 1), and a pure water pump 54 and a pure water supply valve 56 provided in the pure water line 52, respectively. The pure water pump 54 may be driven by a motor 55.

[0023] The pure water supply unit 50 may be configured to supply pure water to the water electrolysis device 2 such that the liquid level in the gas-liquid separator 16 or 36 remains within a predetermined range. For example, the opening degree of the pure water supply valve 56 may be adjusted based on the liquid level measured by a liquid level sensor 60 for measuring the liquid level in the gas-liquid separator 16 or 36 (the cathode-side gas-liquid separator 16 in Figure 1). In this case, the amount of pure water supplied to the electrolyte of the water electrolysis device 2 may be adjusted by adjusting the ratio of time the pure water supply valve 56 is open and closed while keeping the amount of pure water pumped by the pure water pump 54 (the flow rate of pure water in the pure water line) constant. Alternatively, the amount of pure water supplied to the electrolyte of the water electrolysis device 2 may be adjusted by controlling the motor 55 to adjust the amount of pure water pumped by the pure water pump 54 (the flow rate of pure water in the pure water line) while keeping the pure water supply valve 56 open.

[0024] As shown in Figure 1, the hydrogen production equipment 1 may be equipped with pressure sensors 62, 72 for measuring the pressure of the gas discharged from gas discharge lines 18, 38, temperature sensors 64, 74 for measuring the temperature of the gas discharged from gas discharge lines 18, 38, flow sensors 66, 76 for measuring the flow rate of hydrogen gas or oxygen gas flowing through gas discharge lines 18, 38, and / or concentration sensors 68, 78 for measuring the concentration of impurities contained in the hydrogen gas or oxygen gas flowing through gas discharge lines 18, 38. In Figure 1, an example is shown in which each sensor is provided on both the cathode side and the anode side, but each sensor may be provided on either the cathode side or the anode side.

[0025] Furthermore, as shown in Figure 1, the hydrogen production equipment 1 may also include a pure water supply amount measuring unit 58 for measuring the amount of pure water supplied by the pure water supply unit 50. The pure water supply amount measuring unit 58 may include a flow sensor installed in the pure water line 52.

[0026] The pressure sensors 62, 72, temperature sensors 64, 74, flow sensors 66, 76, concentration sensors 68, 78, and / or the flow sensors constituting the pure water supply amount measurement unit 58 are electrically connected to the leak detection device 100, which will be described later, and signals indicating the measured values ​​from each sensor may be sent from each sensor to the leak detection device 100.

[0027] (Electrolyte leak detection device and leak detection method) Figure 2 is a schematic diagram of the leak detection device 100 according to one embodiment. Figures 3 to 6 are block diagrams showing the configuration of the leak detection device 100 according to one embodiment. Figure 7 is a diagram illustrating a leak detection method according to one embodiment, and shows an example of the time change of the threshold EI_th based on the load (current applied to the electrodes) I in the water electrolysis device, the liquid level L of the gas-liquid separator 16, the measured value M of the pure water supply, the cumulative measured value MI of the pure water supply, the estimated value E of the pure water supply, and the cumulative estimated value EI of the pure water supply. As will be described later, the threshold EI_th based on the cumulative estimated value EI of the pure water supply is obtained by adding a specified value SG to the cumulative estimated value EI of the pure water supply.

[0028] As shown in Figures 2 and 3 to 6, the leak detection device 100 includes an estimated value acquisition unit 102, an integrated estimated value acquisition unit 104, an integrated measured value acquisition unit 106, and a leak detection unit 108. Also, as shown in Figure 2, the leak detection device 100 may include a supply valve abnormality detection unit 110 (see also Figures 4 and 6) and / or a control unit 112.

[0029] The leak detection device 100 includes at least one computer equipped with a processor (CPU, etc.), main memory (memory device; RAM, etc.), auxiliary memory, and an interface. The leak detection device 100 receives signals indicating measured values ​​from the pressure sensors 62, 72, temperature sensors 64, 74, flow sensors 66, 76, concentration sensors 68, 78, and / or flow sensors constituting the pure water supply amount measurement unit 58 via the interface. The processor is configured to process the signals thus received. The processor is also configured to process programs that are loaded into the main memory. This enables the functions of the estimated value acquisition unit 102, the integrated estimated value acquisition unit 104, the integrated measured value acquisition unit 106, and the leak detection unit 108, etc.

[0030] The processing performed by the leak detection device 100 is implemented as a program executed by the processor. The program may be stored, for example, in auxiliary memory. During program execution, these programs are loaded into main memory. The processor reads the program from main memory and executes the instructions contained within it.

[0031] The estimated value acquisition unit 102 is configured to acquire an estimated value of the amount of pure water supplied to the electrolyte (the amount of pure water supplied by the pure water supply unit 50) according to the operating state of the water electrolysis device 2. This estimated value indicates the amount of pure water that needs to be supplied (replenished) according to the actual water consumption of the water electrolysis device 2. The estimated value acquisition unit 102 may acquire the above-mentioned estimated value of the pure water supply at predetermined time intervals (for example, every few seconds or every few minutes).

[0032] In one embodiment, the estimated value acquisition unit 102 may acquire the aforementioned estimated value based on a pre-prepared correlation between the load of the water electrolysis apparatus 2 and the supply amount of pure water to the electrolyte solution. The load of the water electrolysis apparatus 2 may be a current value applied to the electrolytic cell 4. Further, the load of the water electrolysis apparatus 2 may be expressed as a ratio relative to the load (100%) during rated operation. Note that the higher the load of the water electrolysis apparatus 2, the greater the amount of hydrogen generated by water electrolysis (that is, the greater the water consumption), and therefore, in the aforementioned correlation, the higher the load of the water electrolysis apparatus 2, the greater the supply amount of pure water to the electrolyte solution.

[0033] The aforementioned correlation may be acquired based on the operation record of the water electrolysis apparatus 2. The aforementioned correlation may be stored in advance in a storage unit (not shown) of the leak detection apparatus 100.

[0034] In the exemplary embodiments shown in FIG. 3 and FIG. 4, the estimated value acquisition unit 102 receives the current load of the water electrolysis apparatus 2 from a control device or the like for controlling the operation of the water electrolysis apparatus 2, acquires the aforementioned correlation stored in advance in the storage unit, and acquires and outputs the pure water supply amount obtained by applying the load to the correlation as the aforementioned estimated value.

[0035] In the example shown in FIG. 7, the estimated value E of the pure water supply amount is acquired based on the correlation between the load (current) of the water electrolysis apparatus 2 and the supply amount of pure water to the electrolyte solution as described above. In the example shown in FIG. 7, the load of the water electrolysis apparatus 2 is I1 between time t0 and t1, I2 (<I1) between time t1 and t2, and I3 (>I1) after time t2, and the estimated value E of the pure water supply amount also differs in each time zone according to the load of the water electrolysis apparatus 2.

[0036] In one embodiment, the estimated value acquisition unit 102 may calculate the water consumption amount in the water electrolysis apparatus 2 based on the flow rate of the gas (hydrogen gas or oxygen gas) discharged from the gas discharge line 18 or 38 of the water electrolysis apparatus 2, and acquire the aforementioned estimated value based on the water consumption amount.

[0037] In the exemplary embodiments shown in Figures 5 and 6, the estimated value acquisition unit 102 may calculate the amount of water consumed by the electrolytic reaction of water using the following electrolytic formula (A) from the flow rate (mass flow rate or volume flow rate) of hydrogen gas in the gas discharge line 18 and / or related process values ​​(for example, the pressure of hydrogen gas measured by the pressure sensor 62, the temperature of hydrogen gas measured by the temperature sensor 64, or the impurity concentration in the hydrogen gas detected by the concentration sensor 68, etc.), and acquire the amount of consumption as the estimated value described above. 2H2O + 2e - → 2OH - +H2…(A)

[0038] Alternatively, the estimated value acquisition unit 102 may further calculate the amount of evaporated water contained in the hydrogen gas in the gas discharge line 18 from the flow rate (mass flow rate or volumetric flow rate) and / or related process values ​​(for example, the pressure of the hydrogen gas measured by the pressure sensor 62 or the temperature of the hydrogen gas measured by the temperature sensor 64) of the hydrogen gas in the gas discharge line 18 and the saturated vapor pressure of water, and acquire the sum of the amount of water consumed by the electrolytic reaction of water described above and the amount of evaporated water as the estimated value described above.

[0039] Alternatively, the estimated value acquisition unit 102 may further calculate the amount of evaporated water contained in the oxygen gas in the gas discharge line 38 from the flow rate (mass flow rate or volumetric flow rate) and / or related process values ​​(for example, the oxygen gas pressure measured by the pressure sensor 72 or the oxygen gas temperature measured by the temperature sensor 74) of the oxygen gas in the gas discharge line 38 and the saturated vapor pressure of water, and acquire the sum of the amount of water consumed by the electrolytic reaction of water described above, the amount of evaporated water contained in the hydrogen gas, and the amount of evaporated water contained in the oxygen gas as the estimated value described above.

[0040] Furthermore, the estimated value acquisition unit 102 may similarly calculate the amount of water consumed and / or evaporated water due to the electrolytic reaction on the anode side (oxygen gas), and acquire an estimated amount of pure water supply based on these values ​​(for example, by taking the average of the estimated values ​​calculated on the hydrogen side and the oxygen side).

[0041] The cumulative estimated value acquisition unit 104 is configured to acquire a cumulative estimated value, which is the cumulative value of the estimated amount of pure water supply obtained by the estimated value acquisition unit 102 from a reference point to the present. The reference point, which is the starting point for the cumulative estimated value, may be the time when the leak detection device 100 receives a plant startup completion signal (see Figures 3 to 6) from a higher-level control device or the like, indicating that the hydrogen production facility 1 has finished starting up.

[0042] The cumulative measurement value acquisition unit 106 is configured to acquire a cumulative measurement value, which is the cumulative value of the pure water supply amount measurement value acquired from the pure water supply amount measurement unit 58 from the above-mentioned reference point to the present. The reference point, which is the starting point for the cumulative measurement value, is the same as the reference point for the cumulative estimate value, or it may be the point at which the leak detection device 100 receives a plant startup completion signal from a higher-level control device or the like, indicating that the hydrogen production facility 1 has finished starting up.

[0043] In the example shown in Figure 7, the measured value M and the integrated measured value MI of the pure water supply amount are shown. In the example shown in Figure 7, the amount of pure water supplied to the electrolyte of the water electrolysis device 2 is adjusted by adjusting the ratio of time the pure water supply valve 56 is open and closed, while keeping the amount of pure water supplied by the pure water pump 54 (flow rate of pure water in the pure water line) constant at X, so that the liquid level L of the gas-liquid separator 16 is within the range of L1 to L2. Therefore, as shown in Figure 7, the measured value M of the pure water supply amount is X when the pure water supply valve 56 is open and zero when it is closed, and the ratio of time the valve is open and closed differs depending on the load of the water electrolysis device 2. That is, when the amount of pure water supplied is large (when the load of the water electrolysis device 2 is high), the ratio of time the valve is open becomes larger.

[0044] The integration of estimated values ​​by the integrated estimated value acquisition unit 104 and the integration of measured values ​​by the integrated measured value acquisition unit 106 may continue until the leak detection device 100 receives a plant shutdown signal (see Figures 3 to 6) from a higher-level control device or the like, indicating that the hydrogen production facility 1 has stopped. The leak detection device 100 may reset the integrated values ​​of the estimated and measured values ​​once it receives the plant shutdown signal.

[0045] The leak detection unit 108 is configured to detect electrolyte leakage from the water electrolysis device 2 based on a comparison between a threshold determined based on the cumulative estimated value obtained by the cumulative estimated value acquisition unit 104 and the cumulative measured value obtained by the cumulative measured value acquisition unit 106.

[0046] In the exemplary embodiments shown in Figures 3 to 6, the leak detection unit 108 includes a subtractor 134 that acquires the difference between the integrated measured value obtained by the integrated measured value acquisition unit 106 and a threshold value based on the integrated estimated value obtained by the integrated estimated value acquisition unit 104, and a comparator 136 that determines whether the difference obtained by the subtractor 134 is greater than zero. The above-mentioned difference being greater than zero suggests that the actual amount of pure water supplied is greater than the required amount of pure water supplied (estimated value) expected from the operating state of the water electrolysis device 2, and that there is a possibility that electrolyte leakage is occurring in the water electrolysis device 2.

[0047] In some embodiments, as shown in Figures 3 to 6, for example, the leak detection unit 108 includes an adder 130 for adding a specified value SG as a margin to the cumulative estimated value of the pure water supply acquired by the cumulative estimated value acquisition unit 104. The sum of the cumulative estimated value and the specified value SG is then input to the subtractor 134 as a threshold. The specified value SG may be stored in memory 132.

[0048] In the example shown in Figure 7, the threshold EI_th, based on the cumulative estimated value EI of the pure water supply, is obtained by adding a specified value SG to the cumulative estimated value EI.

[0049] In the exemplary embodiments shown in Figures 3 and 5, if the difference measured by the comparator 136 is greater than zero (i.e., the cumulative measurement value is greater than the threshold), it is determined that electrolyte leakage has occurred in the water electrolysis device 2, and a leak detection signal is output. In some embodiments, the control unit 112 receives the leak detection signal from the leak detection unit 108.

[0050] In the example shown in Figure 7, at time t3, electrolyte leakage occurs in the water electrolysis device 2. As a result, the measured value of the pure water supply becomes larger than expected (estimated), and at time t4, the accumulated measured value exceeds the threshold EI_th. At this time, the aforementioned leak detection signal is output.

[0051] In the exemplary embodiments shown in Figures 4 and 6, the leak detection unit 108 includes a supply valve abnormality detection unit 110 for detecting abnormalities in the pure water supply valve 56. Based on the comparison result of the cumulative measurement value and the threshold value, and the abnormality detection result by the supply valve abnormality detection unit 110, it determines whether or not electrolyte leakage has occurred from the water electrolysis device 2.

[0052] The supply valve abnormality detection unit 110 includes a NOT gate 138 capable of receiving a pure water supply valve open command signal, and an AND gate 140 capable of receiving the output of the NOT gate 138 and a pure water supply valve open signal indicating that the pure water supply valve 56 is in the open state. The NOT gate 138 outputs an ON signal when it has not received a pure water supply valve open command signal (i.e., when no open command has been issued to the pure water supply valve 56). When the AND gate 140 receives an ON signal from the NOT gate 138 and has also received a pure water supply valve open signal (i.e., when the pure water supply valve 56 is in the open state despite no open command being issued to the pure water supply valve 56), it is determined that there is an abnormality in the pure water supply valve 56, and a supply valve abnormality detection signal is output.

[0053] Furthermore, in the exemplary embodiments shown in Figures 4 and 6, the leak detection unit 108 includes a NOT gate 142 capable of receiving a supply valve abnormality detection signal, and an AND gate 144 capable of receiving the output of the NOT gate 142 and the output of the comparator 136 described above. The NOT gate 142 outputs an ON signal when it has not received a supply valve abnormality detection signal from the AND gate 140 (i.e., when no abnormality of the pure water supply valve 56 has been detected). The AND gate 144 receives an ON signal from the NOT gate 142 and a signal from the comparator 136 indicating that the difference between the cumulative measured value and the threshold is greater than zero (i.e., when the cumulative measured value is greater than the threshold and it is determined that there is no abnormality of the pure water supply valve 56), and it is determined that electrolyte leakage has occurred in the water electrolysis device 2, and a leak detection signal is output. As described above, the leak detection signal from the leak detection unit 108 may be received by the control unit 112.

[0054] In one embodiment, the control unit 112 controls the water electrolysis device 2 to stop operation when it receives a leak detection signal. For example, the control unit 112 controls the rectifier 8 to stop applying current to the electrodes of the electrolytic cell 4. Alternatively, in one embodiment, the control unit 112 controls the water electrolysis device 2 to stop supplying pure water to the electrolyte when it receives a leak detection signal. For example, the control unit 112 controls the actuator of the pure water supply valve 56 to close the pure water supply valve 56. Alternatively, in one embodiment, the control unit 112 may output visual or auditory information indicating an alarm to the display unit 120 or speaker 122 when it receives a leak detection signal.

[0055] According to the above embodiment, an integrated estimated value is obtained, which is the cumulative value from a reference point of the estimated amount of pure water supplied to the electrolyte according to the operating state of the water electrolysis device 2, and an integrated measured value is obtained, which is the cumulative value from a reference point of the measured amount of pure water supplied to the electrolyte. Here, the integrated estimated value indicates the amount of pure water consumed according to the operating state (load, etc.) of the water electrolysis device 2. Therefore, if the integrated measured value is greater than a threshold based on the integrated estimated value, it can be determined that there is a possibility that electrolyte is leaking from the water electrolysis device 2. In this way, in the above embodiment, electrolyte leakage from the water electrolysis device 2 can be appropriately detected without using a leak sensor. In other words, according to the above embodiment, electrolyte leakage from the water electrolysis device 2 can be appropriately detected while reducing costs.

[0056] Here, in addition to electrolyte leakage, a possible cause for the supply of pure water being greater than the water consumption in the water electrolysis device 2 is abnormal opening and closing of the pure water supply valve 56 for supplying pure water. In this regard, according to the embodiments shown in Figures 4 and 6, when it is determined that there is a possibility of electrolyte leakage because the cumulative measured value of the pure water supply is greater than the threshold (i.e., the difference between the cumulative measured value and the threshold is greater than zero), it is determined that electrolyte is leaking from the water electrolysis device 2 only when it is determined that there is no abnormality in the pure water supply valve 56. Thus, electrolyte leakage from the water electrolysis device 2 can be detected more reliably.

[0057] As an alternative to the leak detection method according to the above embodiment, if the amount of pure water supplied by the pure water pump 54 (flow rate of pure water in the pure water line) is kept constant so that the liquid level in the gas-liquid separator 16 is within a predetermined range, and the amount of pure water supplied is adjusted by adjusting the ratio of time the pure water supply valve 56 is open and closed, then the possibility of electrolyte leakage can be detected based on the ratio of time the pure water supply valve 56 is open and closed (i.e., by supply on / off time management). For example, in the example shown in Figure 7, as indicated by the dashed line indicated by symbol A, if the pure water supply valve 56 is open for a longer period than expected, it can be determined that there is a possibility of electrolyte leakage. However, with this detection method, if the pure water supply flow rate changes for any reason, leakage may not be detected or may result in false detections. Also, if the pure water supply valve 56 is kept open due to malfunction or sticking, there is a risk of false detections.

[0058] In contrast, the above-described embodiment takes into account the possibility of malfunctions or sticking of the pure water supply valve 56, making false detections less likely. Furthermore, based on a comparison between a threshold value based on the cumulative estimated value and the cumulative measured value, electrolyte leakage can be detected relatively quickly after it occurs.

[0059] The contents described in each of the above embodiments can be understood, for example, as follows:

[0060] [1] A leak detection method according to at least one embodiment of the present invention is: A method for detecting electrolyte leakage from a water electrolysis device (2), The aforementioned water electrolysis apparatus is An electrolytic cell (4) for storing the electrolyte, A gas-liquid separator (16, 36) into which the gas generated in the electrolytic cell is introduced, The electrolytic cell and the gas-liquid separator include a circulation line (10, 30) for circulating the electrolyte between them. The steps include obtaining an integrated estimated value, which is the cumulative value from a reference point of the estimated amount of pure water supplied to the electrolyte according to the operating state of the water electrolysis apparatus, The steps include obtaining an integrated measurement value, which is the cumulative value of the measured amount of pure water supplied to the electrolyte from the reference point, A leak detection step that detects leakage of the electrolyte from the water electrolysis device based on a comparison between a threshold determined based on the cumulative estimated value and the cumulative measured value, It is equipped with.

[0061] In a water electrolysis device, water is consumed by the electrolysis of water contained in the electrolyte, so pure water (makeup water) is supplied to the electrolyte to replenish the consumed water. According to the method described in [1] above, an integrated estimated value is obtained, which is the cumulative value from a reference point of the estimated amount of pure water supplied to the electrolyte according to the operating state of the water electrolysis device, and an integrated measured value is obtained, which is the cumulative value from a reference point of the measured amount of pure water supplied to the electrolyte. Here, the integrated estimated value indicates the amount of pure water consumed according to the operating state (load, etc.) of the water electrolysis device. Therefore, if the integrated measured value is greater than the threshold value based on the integrated estimated value, it can be determined that there is a possibility that electrolyte is leaking from the water electrolysis device. In this way, the method described in [1] above can appropriately detect electrolyte leakage from a water electrolysis device without using a leak sensor. In other words, the method described in [1] above can appropriately detect electrolyte leakage from a water electrolysis device while reducing costs.

[0062] [2] In some embodiments, in the method of [1] described above, The aforementioned leakage detection method is The step of obtaining the estimated value based on the correlation between the load of the pre-prepared water electrolysis device and the amount of pure water supplied to the electrolyte, In the step of obtaining the cumulative estimated value, the cumulative value obtained from the reference point based on the correlation is obtained as the cumulative estimated value.

[0063] According to the method described in [2] above, based on the correlation between the load of the water electrolysis device and the amount of pure water supplied to the electrolyte, it is possible to appropriately obtain an estimated value of the amount of pure water supplied corresponding to the load of the water electrolysis device at each time point from a reference point, and based on this estimated value, it is possible to appropriately obtain an estimated cumulative value from the reference point. Therefore, according to the method described in [2] above, leakage of electrolyte from the water electrolysis device can be appropriately detected while reducing costs.

[0064] [3] In some embodiments, in the method of [1] described above, The aforementioned leakage detection method is The system includes the steps of calculating the amount of water consumed in the water electrolysis device based on the flow rate of gas discharged from the water electrolysis device, and obtaining the estimated value based on the amount of water consumed. In the step of obtaining the cumulative estimated value, the cumulative value obtained from the reference point of the estimated value obtained based on the water consumption is obtained as the cumulative estimated value.

[0065] According to the method described in [3] above, the amount of water consumed in the water electrolysis device is calculated based on the flow rate of gas discharged from the water electrolysis device. Therefore, based on this water consumption, an estimated value of the amount of pure water supplied at each time point from the base point can be appropriately obtained, and based on this estimated value, an estimated cumulative value from the base point can be appropriately obtained. Thus, according to the method described in [3] above, leakage of electrolyte from the water electrolysis device can be appropriately detected while reducing costs.

[0066] [4] In some embodiments, in any of the methods described in [1] to [3] above, The threshold value is obtained by adding a specified value to the cumulative estimated value.

[0067] According to the method described in [4] above, a threshold value obtained by adding a specified value (margin) to the cumulative estimated value is used as the threshold value to be compared with the cumulative measured value. Therefore, based on the comparison between the cumulative measured value and the threshold value, leakage of electrolyte from the water electrolysis device can be appropriately detected while tolerating a certain degree of estimation and measurement error.

[0068] [5] In some embodiments, in the methods described in [1] to [4] above, The aforementioned leakage detection method is The system includes a step of determining whether or not there is an abnormality in the pure water supply valve (56) for supplying pure water to the electrolyte, In the leak detection step, if the cumulative measurement value is greater than the threshold and the determination step determines that there is no abnormality in the pure water supply valve, it is determined that the electrolyte is leaking from the water electrolysis device.

[0069] In addition to electrolyte leakage, a possible cause of the supply of pure water exceeding the water consumption in a water electrolysis device is abnormal opening and closing of the pure water supply valve. According to the method described in [5] above, when it is determined that there is a possibility of electrolyte leakage because the cumulative measurement value is greater than the threshold, it is determined that electrolyte is leaking from the water electrolysis device only when it is determined that there is no abnormality in the pure water supply valve. This makes it possible to detect electrolyte leakage from the water electrolysis device more reliably.

[0070] [6] In some embodiments, in any of the methods described in [1] to [5] above, The aforementioned leakage detection method is If the leak detection step determines that the electrolyte is leaking from the water electrolysis device, the system includes steps to stop the operation of the water electrolysis device, stop the supply of pure water to the electrolyte, or issue an alarm.

[0071] According to the method described in [6] above, if a leak of electrolyte from the water electrolysis device is detected, the operation of the water electrolysis device is stopped, the supply of pure water to the electrolyte is stopped, or an alarm is issued. This suppresses the spread of damage caused by the electrolyte leak and also prevents further leakage of the electrolyte.

[0072] [7] A leak detection device (100) according to at least one embodiment of the present invention is A leak detection device for detecting the leakage of electrolyte from a water electrolysis apparatus (2), The integrated estimated value acquisition unit (104) acquires an integrated estimated value which is the cumulative value from a reference point of the estimated amount of pure water supplied to the electrolyte according to the operating state of the water electrolysis apparatus, The integrated measurement value acquisition unit (106) acquires an integrated measurement value which is the cumulative value of the measured amount of pure water supplied to the electrolyte from the reference time, A leak detection unit (108) detects leakage of the electrolyte from the water electrolysis device based on a comparison between a threshold value determined based on the cumulative estimated value and the cumulative measured value, It is equipped with.

[0073] In a water electrolysis device, water is consumed by the electrolysis of water contained in the electrolyte, so pure water (makeup water) is supplied to the electrolyte to replenish the consumed water. According to the configuration described in [7] above, an integrated estimated value is obtained, which is the cumulative value from a reference point of the estimated amount of pure water supplied to the electrolyte according to the operating state of the water electrolysis device, and an integrated measured value is obtained, which is the cumulative value from a reference point of the measured amount of pure water supplied to the electrolyte. Here, the integrated estimated value indicates the amount of pure water consumed according to the operating state (load, etc.) of the water electrolysis device. Therefore, if the integrated measured value is greater than a threshold based on the integrated estimated value, it can be determined that there is a possibility that electrolyte is leaking from the water electrolysis device. In this way, with the configuration described in [7] above, electrolyte leakage from the water electrolysis device can be appropriately detected without using a leak sensor. In other words, with the configuration described in [7] above, electrolyte leakage from the water electrolysis device can be appropriately detected while reducing costs.

[0074] [8] A hydrogen production facility (1) according to at least one embodiment of the present invention is An electrolytic cell (4) for storing the electrolyte, A gas-liquid separator (16, 36) into which the gas generated in the electrolytic cell is introduced, A circulation line (10, 30) for circulating the electrolyte between the electrolytic cell and the gas-liquid separator, A water electrolysis apparatus (2) including, A leak detection device (100) as described in [7] above, configured to detect leakage of the electrolyte from the water electrolysis apparatus, It is equipped with.

[0075] In a water electrolysis device, water is consumed by the electrolysis of water contained in the electrolyte, so pure water (makeup water) is supplied to the electrolyte to replenish the consumed water. According to the configuration in [8] above, an integrated estimated value is obtained, which is the cumulative value from a reference point of the estimated amount of pure water supplied to the electrolyte according to the operating state of the water electrolysis device, and an integrated measured value is obtained, which is the cumulative value from a reference point of the measured amount of pure water supplied to the electrolyte. Here, the integrated estimated value indicates the amount of pure water consumed according to the operating state (load, etc.) of the water electrolysis device. Therefore, if the integrated measured value is greater than the threshold based on the integrated estimated value, it can be determined that there is a possibility that electrolyte is leaking from the water electrolysis device. In this way, with the configuration in [7] above, electrolyte leakage from the water electrolysis device can be appropriately detected without using a leak sensor. In other words, with the configuration in [8] above, electrolyte leakage from the water electrolysis device can be appropriately detected while reducing costs.

[0076] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0077] In this specification, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" shall not only describe such arrangements strictly, 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 such as "identical," "equal," and "homogeneous" that describe things being in an equal state not only describe a state of being strictly equal, but also describe a state in which there is a tolerance or a difference that is sufficient to achieve the same function. Furthermore, in this specification, expressions describing shapes such as quadrilaterals and cylindrical shapes shall not only represent geometrically precise quadrilaterals and cylindrical shapes, but also shapes that include uneven surfaces, chamfered surfaces, etc., to the extent that the same effect can be achieved. Furthermore, in this specification, the expressions “equipment,” “includes,” or “possess” of a component are not exclusive expressions that exclude the existence of other components. [Explanation of symbols]

[0078] 1. Hydrogen production equipment 2 Water electrolysis device 4 Electrolytic cell 8 rectifier 10 Circulation Line 12 Exit Line 14 Entrance Line 16 Gas-liquid separator 18 Gas Emission Line 20 Cooler 22 Circulation pump 30 Circulation Line 32 Exit Line 34 Entrance Line 36 Gas-liquid separator 38 Gas emission line 40 Cooler 42 Circulation pump 50 Pure water supply section 52 Pure water line 54 Pure water pump 55 Motor 56 Pure water supply valve 58 Pure water supply amount measurement unit 60 Liquid level sensor 62 Pressure Sensor 64 Temperature Sensors 66 Flow Sensor 68 Concentration Sensor 72 Pressure Sensor 74 Temperature Sensor 76 Flow Sensor 78 Concentration Sensor 100 Leak detection device 102 Estimate acquisition unit 104 Unit for obtaining cumulative estimated value 106 Cumulative Measurement Value Acquisition Unit 108 Leak detection unit 110 Supply valve abnormality detection unit 112 Control Unit 120 Display section 122 speakers 130 Adder 132 memory 134 Subtractor 136 Comparator 138 NOT Gate 140 AND Gate 142 NOT Gates 144 AND Gate E Estimate EI (Estimated Value) EI_th threshold L liquid level M Measured value

Claims

1. A method for detecting electrolyte leakage from a water electrolysis device, The aforementioned water electrolysis apparatus is An electrolytic cell for storing electrolyte, A gas-liquid separator through which the gas generated in the electrolytic cell is introduced, The electrolytic cell and the gas-liquid separator include a circulation line for circulating the electrolyte between them, The steps include obtaining an integrated estimate, which is the cumulative value of the estimated amount of pure water supplied to the electrolyte from a reference point, The steps include obtaining an integrated measurement value, which is the cumulative value of the measured amount of pure water supplied to the electrolyte from the reference point, A leak detection step that detects leakage of the electrolyte from the water electrolysis device based on a comparison between a threshold determined based on the cumulative estimated value and the cumulative measured value, A leak detection method comprising the following:

2. The step of obtaining the estimated value based on the correlation between the load of the pre-prepared water electrolysis device and the amount of pure water supplied to the electrolyte, In the step of obtaining the cumulative estimated value, the cumulative value obtained from the reference point based on the correlation is obtained as the cumulative estimated value. The leakage detection method according to claim 1.

3. The system includes the steps of calculating the amount of water consumed in the water electrolysis device based on the flow rate of gas discharged from the water electrolysis device, and obtaining the estimated value based on the amount of water consumed. In the step of obtaining the cumulative estimated value, the cumulative value obtained from the reference point of the estimated value obtained based on the water consumption is obtained as the cumulative estimated value. The leakage detection method according to claim 1.

4. The threshold value is obtained by adding a specified value to the cumulative estimated value. A leak detection method according to any one of claims 1 to 3.

5. The system includes a step of determining whether or not there is any abnormality in the pure water supply valve for supplying pure water to the electrolyte, In the leak detection step, if the cumulative measurement value is greater than the threshold and the determination step determines that there is no abnormality in the pure water supply valve, it is determined that the electrolyte is leaking from the water electrolysis device. A leak detection method according to any one of claims 1 to 3.

6. If the leak detection step determines that the electrolyte is leaking from the water electrolysis device, the system includes steps to stop the operation of the water electrolysis device, stop the supply of pure water to the electrolyte, or issue an alarm. A leak detection method according to any one of claims 1 to 3.

7. A leak detection device for detecting electrolyte leakage from a water electrolysis apparatus, A cumulative estimated value acquisition unit acquires a cumulative estimated value which is the cumulative value from a reference point of the estimated amount of pure water supplied to the electrolyte according to the operating state of the water electrolysis apparatus, A unit for acquiring cumulative measurement values, which is the cumulative value of the measured amount of pure water supplied to the electrolyte from the reference point, A leak detection unit detects leakage of the electrolyte from the water electrolysis device based on a comparison between a threshold value determined based on the cumulative estimated value and the cumulative measured value. A leak detection device equipped with [a specific feature].

8. An electrolytic cell for storing electrolyte, A gas-liquid separator through which the gas generated in the electrolytic cell is introduced, A circulation line for circulating the electrolyte between the electrolytic cell and the gas-liquid separator, A water electrolysis device including, A leak detection device according to claim 7, configured to detect leakage of the electrolyte from the water electrolysis apparatus, A hydrogen production facility equipped with the following features.

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