Electrochemical hydrogen boosting system

Abstract

To provide an electrochemical hydrogen booster system in which a regenerated hydrogen gas can be utilized without being discharged to the outside as waste and the decline of a hydrogen production efficiency of the electrochemical hydrogen booster system can be suppressed.SOLUTION: An electrochemical hydrogen booster system 10 comprises: a hydrogen booster stack 16 for releasing a hydrogen gas supplied to an anode electrode as a highly pressured hydrogen gas boosted from a cathode electrode through a polymer electrolyte; a hydrogen supply apparatus 14 for supplying the hydrogen gas to the anode electrode of the hydrogen booster stack 16 through a hydrogen supply flow path 60; a PSA apparatus 22 including multiple adsorption towers 24 for dehumidifying the highly pressurized hydrogen gas released from the hydrogen booster stack 16; and a return flow path 94 for recycling a regenerated hydrogen gas utilized for the regeneration in the adsorption tower 24 into the hydrogen supply flow path 60 or the hydrogen supply apparatus 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an electrochemical hydrogen boosting system. [Background technology]

[0002] In recent years, research and development has been conducted on electrochemical hydrogen boosting systems that contribute to energy efficiency, ensuring that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] Patent Document 1 discloses an electrochemical hydrogen boosting system for boosting the pressure of hydrogen gas. This electrochemical hydrogen boosting system includes an electrochemical hydrogen boosting device. The electrochemical hydrogen boosting device has a unit cell formed by a proton exchange membrane (electrolyte membrane) and an anode and a cathode provided on either side of the proton exchange membrane, and by applying a current between the anode and the cathode, the hydrogen gas supplied to the anode is boosted and high-pressure hydrogen gas is generated at the cathode.

[0004] Patent Document 2 discloses a PSA dehumidifier that obtains low dew point air by pressure swing adsorption. This PSA dehumidifier alternates between a treatment step in which treated air is passed through an adsorption vessel containing an adsorbent and a regeneration step in which regeneration air is passed through the vessel, thereby obtaining low dew point air by pressure swing adsorption. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2022-94891 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-291732 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the high-pressure hydrogen gas obtained by the electrochemical hydrogen boosting system contains a large amount of moisture. Therefore, when supplying this hydrogen gas to the hydrogen tank of a fuel cell system installed in a mobile object such as a vehicle, it is necessary to remove the moisture contained in the hydrogen gas. In this case, it is possible to remove the moisture contained in the hydrogen gas using a PSA device.

[0007] The PSA device has at least two adsorption towers containing adsorbent. When the amount of moisture adsorbed in one adsorption tower reaches its upper limit, the PSA device switches to the other adsorption tower to continue removing moisture, while circulating hydrogen gas for regeneration through the other adsorption tower to release the adsorbed moisture. Because the regenerated hydrogen gas used for regeneration contains a large amount of moisture, it is not suitable for use in fuel cell systems, and there was an issue of reduced hydrogen production efficiency in electrochemical hydrogen boosting systems.

[0008] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0009] A first aspect of the present disclosure is an electrochemical hydrogen boosting system comprising: a hydrogen boosting stack having a single cell including an electrolyte membrane, an anode electrode provided on one side of the electrolyte membrane, and a cathode electrode provided on the other side of the electrolyte membrane, the hydrogen boosting stack supplying hydrogen gas to the anode electrode and releasing pressurized high-pressure hydrogen gas from the cathode electrode; a power supply device applying voltage to the hydrogen boosting stack; a hydrogen supply device supplying hydrogen gas to the hydrogen boosting stack via a hydrogen supply flow path; and a PSA device having a plurality of adsorption towers that dehumidify the high-pressure hydrogen gas released from the hydrogen boosting stack, the system having a return flow path that returns regenerated hydrogen gas used to regenerate the adsorption towers to the hydrogen supply flow path of the hydrogen boosting stack or the hydrogen supply device. [Effects of the Invention]

[0010] According to the above aspect, the regenerated hydrogen gas used for regeneration is returned to the hydrogen supply line or the hydrogen supply device of the hydrogen booster stack via the return line, so that the regenerated hydrogen gas can be used without being discharged to the outside, thereby preventing a decrease in the hydrogen production efficiency of the electrochemical hydrogen booster system. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of an electrochemical hydrogen boosting system according to an embodiment. [Figure 2] Fig. 2(a) is an explanatory diagram relating to the adsorption process of adsorption tower A of the PSA system. Fig. 2(b) is an explanatory diagram relating to the adsorption process of adsorption tower B of the PSA system. Fig. 2(c) is an explanatory diagram relating to the regeneration process of adsorption tower A of the PSA system. Fig. 2(d) is an explanatory diagram relating to the regeneration process of adsorption tower B of the PSA system. [Figure 3] FIG. 3 is a flow chart of the adsorption process and regeneration process of the PSA unit. [Figure 4] FIG. 4 is a flowchart of the adsorption process and regeneration process of the PSA unit, following FIG. [Figure 5] FIG. 5 is a timing chart showing the steps in adsorption tower A and adsorption tower B and the supply of raw hydrogen. DETAILED DESCRIPTION OF THE INVENTION

[0012] 1 is a schematic diagram showing an embodiment of an electrochemical hydrogen boosting system 10. The electrochemical hydrogen boosting system 10 includes an electrochemical hydrogen boosting device 12, a hydrogen supply device 14, a gas-liquid separator 18, a condenser 20, a PSA device 22, and a control device 30.

[0013] The electrochemical hydrogen booster 12 electrochemically boosts the pressure of hydrogen gas and includes a hydrogen booster stack 16 and a power supply 28 that applies a voltage to the hydrogen booster stack 16.

[0014] The hydrogen booster stack 16 has a hydrogen inlet PT1, a hydrogen outlet PT2, and a high-pressure hydrogen outlet PT3. The hydrogen inlet PT1 supplies hydrogen gas from the hydrogen supply device 14 to the hydrogen booster stack 16. The supplied hydrogen gas is connected to the anode electrode 36 of each unit cell 32. The hydrogen outlet PT2 discharges unused hydrogen gas. The high-pressure hydrogen outlet PT3 releases high-pressure hydrogen gas generated in the unit cell 32. The high-pressure hydrogen gas is connected to the cathode electrode 40 of each unit cell 32.

[0015] The hydrogen booster stack 16 is configured by stacking a plurality of unit cells 32. All of the unit cells 32 have the same structure. Each unit cell 32 has an electrolyte membrane 34, an anode electrode 36 provided on one side of the electrolyte membrane 34, an anode power supply 37, a cathode electrode 40 provided on the other side of the electrolyte membrane 34, and a cathode power supply 41.

[0016] The electrolyte membrane 34 may be, for example, a solid polymer electrolyte membrane (cation exchange membrane). The anode side of the electrolyte membrane 34 may be reinforced with a protective sheet (not shown) including a fibrous skeleton. This allows the electrolyte membrane 34 to withstand the pressure of high-pressure hydrogen gas applied from the cathode side. In addition to a fluorine-based electrolyte, an HC (hydrocarbon)-based electrolyte may also be used for the electrolyte membrane 34. The electrolyte membrane 34 is sandwiched between the anode electrode 36 and the cathode electrode 40.

[0017] The anode electrode 36 includes an anode catalyst layer bonded to one side of the electrolyte membrane 34. An anode power supply 37 is laminated on the anode catalyst layer. The anode catalyst layer includes a platinum-based catalyst. An anode flow path through which hydrogen gas flows is formed in the anode power supply 37. Hydrogen gas supplied from the hydrogen inlet PT1 flows through the anode flow path and reaches the anode catalyst layer. A porous reinforcing plate may be interposed between the anode catalyst layer and the anode power supply 37. The reinforcing plate can effectively withstand the pressure of high-pressure hydrogen gas applied from the cathode side.

[0018] The cathode electrode 40 includes a cathode catalyst layer bonded to the other surface of the electrolyte membrane 34. A cathode current collector 41 is laminated on the cathode catalyst layer. The cathode catalyst layer includes a platinum-based catalyst. A cathode flow path through which pressurized high-pressure hydrogen gas flows is formed in the cathode current collector 41. The generated high-pressure hydrogen gas flows through the cathode flow path and is released from a high-pressure hydrogen outlet PT3.

[0019] When a voltage is applied between the anode electrode 36 and the cathode electrode 40, hydrogen gas supplied to the anode electrode 36 from the hydrogen inlet PT1 is ionized into protons (hydrogen ions) and electrons by a catalytic reaction in the anode catalyst layer. The generated protons permeate the electrolyte membrane 34 and move to the cathode electrode 40. At this time, the protons carry moisture with them to the cathode electrode 40. Therefore, the hydrogen gas supplied to the anode electrode 36 must be humidified. At the cathode electrode 40, high-pressure hydrogen gas is generated by an electrochemical reaction in which the protons that have permeated the electrolyte membrane 34 combine with the electrons. Unused hydrogen gas that is not ionized at the anode electrode 36 is discharged from the hydrogen outlet PT2. The pressure of the high-pressure hydrogen gas flowing through the cathode flow path is higher than the pressure of the hydrogen gas flowing through the anode flow path.

[0020] The power supply 28 applies a DC voltage to the hydrogen booster stack 16, causing a current to flow through the hydrogen booster stack 16. The hydrogen booster stack 16 includes a stack of multiple unit cells 32, with an anode connection terminal and a cathode connection terminal (not shown) disposed at each end of the stack. The positive electrode of the power supply 28 is connected to the anode connection terminal via a connection cable, and the negative electrode of the power supply 28 is connected to the cathode connection terminal via a connection cable. As a result, a positive potential is applied to the anode electrode 36 of each unit cell 32, and a negative potential is applied to the cathode electrode 40 of each unit cell 32.

[0021] The power supply device 28 is configured to be able to adjust the magnitude of the voltage applied to the hydrogen booster stack 16 in response to a control command from the control device 30. The voltage supplied to the hydrogen booster stack 16 is applied evenly to each unit cell 32. The higher the voltage supplied to the hydrogen booster stack 16, the greater the current that flows, and the greater the amount of high-pressure hydrogen gas generated in the hydrogen booster stack 16.

[0022] The hydrogen supply device 14 includes a sealed container 44 in which liquid water is stored downward in the direction of gravity. Raw hydrogen is supplied into the liquid water in the sealed container 44 via a raw hydrogen supply line 50. A raw hydrogen valve 52 is provided on the raw hydrogen supply line 50. The raw hydrogen valve 52 allows raw hydrogen to flow when opened and stops the flow of raw hydrogen when closed.

[0023] An opening is provided at one end of the raw hydrogen supply path 50, and this opening is open in the liquid water of the sealed container 44. Hydrogen gas, which is raw hydrogen, is released from the opening and becomes bubbles in the liquid water, which rise to the top of the sealed container 44. At this time, the liquid droplets contained in the raw hydrogen are taken into the liquid water. In addition, the hydrogen gas that has risen to the top of the liquid water is humidified by the liquid water. The sealed container 44 functions both as the gas-liquid separator 18 and as a humidifier.

[0024] The feed hydrogen need only contain hydrogen gas and can be produced, for example, by electrolysis of water. Alternatively, feed hydrogen can be produced by a reforming reaction from a feed containing hydrocarbons. The feed hydrogen may contain conductive components such as potassium hydroxide contained in the electrolyte when water is electrolyzed, and impurities other than the hydrogen gas produced during the reforming reaction. These impurities are removed in the hydrogen booster stack 16 and are not contained in the high-pressure hydrogen gas produced.

[0025] A space 45 is formed above the liquid water stored in the sealed container 44, in which hydrogen gas that has passed through the liquid water and been humidified is collected. The hydrogen gas contained within the space 45 is pressurized to a predetermined pressure. A pressure sensor 64 that communicates with the space 45 and measures the pressure of the hydrogen gas contained in the space 45 is provided in the sealed container 44. A hydrogen outlet 46 that communicates with the space 45 and discharges the hydrogen gas is also provided above the sealed container 44. The hydrogen gas pressurized to a predetermined pressure is discharged from the hydrogen outlet 46.

[0026] The hydrogen outlet 46 communicates with a hydrogen inlet PT1 of the hydrogen booster stack 16 via a hydrogen supply passage 60. The hydrogen outlet PT2 of the hydrogen booster stack 16 is connected to a hydrogen circulation port 67 of the sealed container 44 via a hydrogen circulation passage 62. The hydrogen circulation port 67 communicates with the liquid water in the sealed container 44. Unused hydrogen gas in the hydrogen booster stack 16 is circulated to the sealed container 44. A circulation pump 66 for circulating hydrogen gas is provided in the hydrogen circulation passage 62.

[0027] The high-pressure hydrogen outlet PT3 of the hydrogen booster stack 16 is connected to an inlet passage 80 of the PSA unit 22 via a high-pressure hydrogen supply passage 70. The high-pressure hydrogen supply passage 70 is provided with, in order from the upstream side, a back pressure valve 71, a check valve 72, a gas-liquid separator 18, and a condenser 20. The condenser 20 may be provided according to the specifications required for the high-pressure hydrogen gas, and may be omitted.

[0028] The back pressure valve 71 adjusts the pressure of the high-pressure hydrogen gas discharged from the hydrogen booster stack 16. The check valve 72 allows the high-pressure hydrogen gas to flow from the hydrogen booster stack 16 to the gas-liquid separator 18, and prevents the high-pressure hydrogen gas from flowing back from the gas-liquid separator 18 to the hydrogen booster stack 16.

[0029] The gas-liquid separator 18 removes liquid components (liquid droplets) contained in the high-pressure hydrogen gas as liquid water. The gas-liquid separator 18 supplies the high-pressure hydrogen gas from which the liquid water has been removed to a PSA device 22 provided downstream. The gas-liquid separator 18 is a sealed container. In a containerA level switch 77 for measuring the amount of liquid water stored inside the gas-liquid separator 18 is provided. vessel Measure the height of the liquid level (top surface of liquid water) stored inside.

[0030] A drain flow path 78 that discharges separated liquid water to the outside is connected to the lower side of the gas-liquid separator 18 in the direction of gravity. A throttle valve 75 and an on-off valve 79 are provided in the drain flow path 78, in that order from upstream to downstream. The throttle valve 75 adjusts the flow rate of liquid water flowing through the drain flow path 78. The on-off valve 79 discharges liquid water from the drain flow path 78 by opening it, and stops discharging liquid water by closing it. When the control device 30 detects, based on a signal from the level switch 77, that liquid water accumulated inside the gas-liquid separator 18 exceeds the upper limit, the control device 30 opens the on-off valve 79 and discharges the liquid water to the outside.

[0031] A relief flow path 76 that communicates with the high-pressure hydrogen gas inside is connected above the gas-liquid separator 18 in the direction of gravity. A pressure reducing valve 73 and a flow rate control valve 74 are provided in the relief flow path 76, in that order from upstream to downstream. In the relief flow path 76, the pressure inside the flow path leading to the hydrogen pressurization stack 16 is relieved by adjusting and operating the pressure reducing valve 73 and the flow rate control valve 74. The pressure reducing valve 73 reduces the pressure of the high-pressure hydrogen gas flowing through the relief flow path 76 to a pressure suitable for depressurization. The flow rate control valve 74 adjusts the flow rate of the high-pressure hydrogen gas flowing through the relief flow path 76, and by closing it, stops the release of hydrogen gas.

[0032] The condenser 20 is provided between the gas-liquid separator 18 and the PSA unit 22. The condenser 20 cools the high-pressure hydrogen gas by exchanging heat with the circulating high-pressure hydrogen gas. This condenses water vapor, which is the moisture contained in the high-pressure hydrogen gas, and reduces the humidity of the high-pressure hydrogen gas.

[0033] [PSA device] The PSA device 22 shown in FIG. 1 will now be described.

[0034] The PSA unit 22 according to this embodiment includes a plurality of adsorption towers 24 (adsorption tower A and adsorption tower B). The plurality of adsorption towers 24 are alternately switched to adsorb moisture contained in introduced hydrogen gas using an adsorbent and discharge dry hydrogen gas. When the amount of adsorbed moisture reaches an upper limit, dry hydrogen gas is passed through the adsorption tower 24 to release the adsorbed moisture and perform regeneration. The PSA unit 22 has a hydrogen inlet 110 through which hydrogen gas is introduced and a hydrogen outlet 120 through which hydrogen gas is discharged.

[0035] Each adsorption tower 24 of the PSA unit 22 is filled with a porous adsorbent, such as activated carbon, zeolite, alumina, or silica. The adsorption tower 24 is composed of a cylindrical adsorption vessel. The adsorption vessel is installed with the cylindrical axis aligned with the direction of gravity. However, the axis may also be aligned horizontally. In this embodiment, a PSA unit 22 having two adsorption towers 24 (adsorption tower A and adsorption tower B) will be described. However, the number of adsorption towers 24 is not limited to two, and may be any number, such as three or more.

[0036] A gas inlet (IN) is provided at the bottom end of the adsorption tower 24. Moisture-containing hydrogen gas is supplied from the gas inlet, and the moisture is removed by the adsorbent packed in the adsorption tower 24, and the gas is discharged from the gas outlet (OUT). The gas outlet is provided at the top end of the adsorption tower 24. When the moisture content of the adsorbent contained in the adsorption tower 24 reaches an upper limit, its ability to adsorb moisture decreases, and therefore it is necessary to release the moisture and perform regeneration.

[0037] The multiple adsorption towers 24 include a treatment adsorption tower that adsorbs moisture contained in hydrogen gas to perform an adsorption process, and a regeneration adsorption tower that releases the moisture adsorbed by the adsorbent to perform a regeneration process. In the regeneration process, hydrogen gas that has been dehumidified and dried in the adsorption process of the other adsorption towers 24 is used. However, a hydrogen storage device that stores dried hydrogen gas may be provided inside the electrochemical hydrogen boosting system 10, and hydrogen gas may be supplied from this hydrogen storage device. Each of the multiple adsorption towers 24 alternately performs the adsorption process and the regeneration process.

[0038] The multiple adsorption towers 24 include at least one treatment adsorption tower and at least one regeneration adsorption tower. There may be two or more treatment adsorption towers or two or more regeneration adsorption towers. Hydrogen gas (regenerated hydrogen gas) that is used to regenerate the regeneration adsorption tower and contains moisture is discharged from the regenerated hydrogen outlet 130 of the PSA unit 22. The multiple adsorption towers 24 are configured with the same specifications. However, the adsorption towers 24 may be configured with different specifications.

[0039] The hydrogen inlet 110 of the PSA device 22 is connected to the high-pressure hydrogen outlet PT3 of the hydrogen booster stack 16 via the high-pressure hydrogen supply line 70. The hydrogen outlet 120 of the PSA device 22 is connected to a hydrogen tank or the like (not shown) via a high-pressure hydrogen outlet line 122. A back-pressure valve 124 is provided in the high-pressure hydrogen outlet line 122 to adjust the pressure of the high-pressure hydrogen gas being discharged. The high-pressure hydrogen outlet line 122 is also provided with an on-off valve (not shown), which supplies high-pressure hydrogen gas when opened and stops the supply when closed. A coupler or the like may be provided between the high-pressure hydrogen outlet line 122 and the hydrogen tank to disconnect the hydrogen tank. The hydrogen tank is installed in a mobile vehicle, industrial equipment, stationary power generation plant, or the like equipped with a fuel cell system. The high-pressure hydrogen outlet line 122 may also be directly connected to a fuel cell system without a hydrogen tank. The regenerated hydrogen outlet 130 of the PSA device 22 is connected to the sealed container 44 of the hydrogen supply device 14 via the return line 94. Therefore, the hydrogen gas used for regenerating the regenerative adsorption tower (regenerated hydrogen gas) is returned to the inside of the sealed container 44.

[0040] The return flow path 94 may be connected to the high-pressure hydrogen supply flow path 70 that connects the gas-liquid separator 18 and the hydrogen booster stack 16. In this case, the return flow path 94 is equivalent to being connected to the hydrogen inlet PT1 of the hydrogen booster stack 16. In other words, the regenerated hydrogen gas discharged from the regenerated hydrogen outlet 130 is returned to the equipment upstream of the hydrogen booster stack 16 via the return flow path 94.

[0041] The return flow path 94 has a hydrogen release port at its downstream end. The hydrogen release port opens into the space 45 above the sealed container 44. The hydrogen release port may also open into the liquid water in the sealed container 44. This allows the recycled hydrogen gas released from the hydrogen release port to have water droplets removed in the liquid water and to be well humidified before reaching the upper space 45 and being supplied to the hydrogen booster stack 16 via the hydrogen supply flow path 60.

[0042] The return flow path 94 is provided with a pressure reducing valve 96 and a flow rate control valve 98. The pressure reducing valve 96 reduces the pressure of the regenerated hydrogen gas discharged from the PSA unit 22. The reduced pressure regenerated hydrogen gas circulates downstream. The flow rate control valve 98 adjusts the flow rate of the regenerated hydrogen gas discharged from the PSA unit 22. The flow rate control valve 98 adjusts the flow rate of the regenerated hydrogen gas supplied in accordance with the pressure in the space 45 above the liquid water in the sealed container 44.

[0043] That is, when the flow rate of hydrogen gas supplied from the space 45 of the sealed container 44 to the hydrogen pressurization stack 16 via the hydrogen supply passage 60 increases, the pressure in the space 45 of the sealed container 44 detected by the pressure sensor 64 decreases, and the control device 30 then adjusts the flow control valve 98 so as to increase the flow rate of the regenerated hydrogen gas supplied to the sealed container 44 via the return passage 94. Note that when the regenerated hydrogen gas is being supplied to the sealed container 44 via the return passage 94, raw hydrogen is not supplied to the sealed container 44. That is, the raw hydrogen valve 52 provided on the raw hydrogen supply passage 50 is closed. Note that the pressure of the regenerated hydrogen gas supplied from the return passage 94 is lower than the pressure of the raw hydrogen.

[0044] In addition to the multiple adsorption towers 24, the PSA device 22 has multiple on-off valves VL1 to VL10 that control the flow of hydrogen gas to the adsorption towers 24 based on commands from the control device 30, and multiple connecting flow paths that connect to these on-off valves VL1 to VL10. In the following description, the on-off valves VL1 to VL10 will also be simply referred to as VL1 to VL10. Note that VL5 and VL6 are omitted.

[0045] An inlet channel 80 connected to a hydrogen inlet 110 of the PSA device 22 branches into a first supply channel 82 and a second supply channel 84 at a branch point 86. The first supply channel 82 and the second supply channel 84 are connected to the gas inlets of adsorption towers A and B, respectively. The first supply channel 82 and the second supply channel 84 are provided with on-off valves VL1 and VL2, respectively, to control the flow of hydrogen gas in the first supply channel 82 and the second supply channel 84.

[0046] A first regenerated hydrogen discharge flow path 90, which leads to a regenerated hydrogen discharge port 130, is connected to the first supply flow path 82 downstream of the on-off valve VL1. An on-off valve VL3 is provided in the first regenerated hydrogen discharge flow path 90 to control the flow of hydrogen gas in the first regenerated hydrogen discharge flow path 90. A second regenerated hydrogen discharge flow path 92, which leads to the regenerated hydrogen discharge port 130, is connected to the second supply flow path 84 downstream of the on-off valve VL2. An on-off valve VL4 is provided in the second regenerated hydrogen discharge flow path 92 to control the flow of hydrogen gas in the second regenerated hydrogen discharge flow path 92.

[0047] The first regenerated hydrogen discharge flow path 90 and the second regenerated hydrogen discharge flow path 92 join at a downstream joining point 93 and are connected to a regenerated hydrogen discharge port 130 .

[0048] A first release flow path 102 and a second release flow path 104 are connected to the gas outlet of adsorption tower A and the gas outlet of adsorption tower B, respectively. The first release flow path 102 and the second release flow path 104 join at a junction 106 and are connected to a hydrogen outlet 120 via an outlet path 100. The first release flow path 102 and the second release flow path 104 are provided with on-off valves VL7 and VL8, respectively, which control the flow of hydrogen gas in the first release flow path 102 and the second release flow path 104.

[0049] The first discharge flow path 102 upstream of the on-off valve VL7 and the second discharge flow path 104 upstream of the on-off valve VL8 are connected to each other by an outlet bypass flow path 108. On-off valves VL9 and VL10 are provided in the outlet bypass flow path 108 to control the flow of hydrogen gas in the outlet bypass flow path 108.

[0050] The first release flow path 102 and the second release flow path 104 are provided with dew point meters DP1 and DP2, respectively, that measure the dew point of the hydrogen gas flowing through the flow paths. The dew point is the temperature at which water vapor contained in hydrogen gas condenses when the hydrogen gas is cooled. The dew point is a physical quantity that indicates the amount of moisture contained in hydrogen gas; the lower the dew point, the less moisture the hydrogen gas contains and the drier the hydrogen gas. To measure the dew point, well-known dew point meters (DP1 to DP4), such as capacitance type, mirror cooling type, and quartz oscillator type, are used. In addition, the lead-out path 100 is provided with a dew point meter DP3 that measures the dew point of the hydrogen gas flowing through it. The dew point meter DP3 measures the dew point of the hydrogen gas released from both the first release flow path 102 and the second release flow path 104.

[0051] [PSA device operation] Next, the operation of the PSA unit 22 according to this embodiment will be described with reference to Figures 2(a) to 2(d). In this embodiment, a PSA unit 22 having two adsorption towers 24 will be described. However, in the case of a unit having three or more adsorption towers 24, the operation of alternately performing the adsorption process and the regeneration process is the same as in this embodiment, so detailed description thereof will be omitted.

[0052] FIG. 2(a) shows the adsorption process in which hydrogen gas supplied from the hydrogen boosting stack 16 is introduced into the hydrogen inlet 110 of the PSA unit 22, dehumidified in the adsorption tower A (treatment adsorption tower), and then discharged from the hydrogen outlet 120.

[0053] Specifically, the control device 30 opens valve VL1 and closes valves VL2, VL3, and VL4. As a result, hydrogen gas introduced from the hydrogen booster stack 16 through the hydrogen inlet 110 into the inlet path 80 flows through the branch point 86 and the first supply flow path 82, passes through the on-off valve VL1, and is supplied to the gas inlet of the adsorption tower A. The hydrogen gas supplied to the adsorption tower A is dehumidified by coming into contact with the adsorbent contained inside the adsorption tower A.

[0054] Furthermore, the control device 30 opens valves VL7 and VL9 and closes valves VL8 and VL10. As a result, the dehumidified and dried hydrogen gas (dry hydrogen gas) is released from the gas outlet of the adsorption tower A to the first release flow path 102, passes through the on-off valve VL7, flows through the junction 106 and the outlet path 100, and is discharged from the hydrogen outlet 120.

[0055] The first discharge passage 102 and the outlet passage 100 are provided with dew point meters DP1 and DP3, respectively, to measure the dew point of the hydrogen gas flowing through them.

[0056] 2(b) shows the adsorption process in which hydrogen gas supplied from the hydrogen booster stack 16 is supplied to the hydrogen inlet 110 of the PSA unit 22, dehumidified in adsorption tower B (treatment adsorption tower), and then discharged from the hydrogen outlet 120. This is a state in which operation is switched to adsorption tower B (regeneration adsorption tower) after the amount of moisture adsorbed in adsorption tower A (treatment adsorption tower) has reached its upper limit.

[0057] Specifically, the control device 30 opens valve VL2 and closes valves VL1, VL3, and VL4. As a result, hydrogen gas introduced from the hydrogen booster stack 16 through the hydrogen inlet 110 into the inlet passage 80 flows through the branch point 86 and the second supply passage 84, and is supplied to the gas inlet of the adsorption tower B through the on-off valve VL2. The hydrogen gas supplied to the adsorption tower B is dehumidified by coming into contact with the adsorbent contained inside the adsorption tower B.

[0058] Furthermore, the control device 30 opens valves VL8 and VL10 and closes valves VL7 and VL9. As a result, the dehumidified and dried hydrogen gas (dehumidified hydrogen gas) is released from the gas outlet of the adsorption tower B to the second release flow path 104, passes through the on-off valve VL8, flows through the junction 106 and the outlet path 100, and is discharged from the hydrogen outlet 120.

[0059] The second discharge flow path 104 and the lead-out path 100 are provided with a dew point meter DP2 and a dew point meter DP3, respectively, to measure the dew point of the hydrogen gas flowing therethrough.

[0060] Figure 2(c) shows the regeneration process in which dehumidified hydrogen gas is supplied from adsorption tower B (treatment adsorption tower) to adsorption tower A (regeneration adsorption tower), and the moisture contained in the adsorbent in adsorption tower A is released to regenerate adsorption tower A.

[0061] Specifically, the control device 30 opens valves VL2 and VL3 and closes valves VL1 and VL4. As a result, hydrogen gas introduced from the hydrogen booster stack 16 through the hydrogen inlet 110 into the inlet passage 80 branches at branch point 86, flows through the second supply passage 84, and is supplied to the gas inlet of the adsorption tower B through the on-off valve VL2. The hydrogen gas supplied to the adsorption tower B is dehumidified by coming into contact with the adsorbent contained inside the adsorption tower B.

[0062] Furthermore, the control device 30 opens valves VL8, VL9, and VL10 and closes valve VL7. As a result, dehumidified hydrogen gas is supplied from the gas outlet of adsorption tower B through the outlet bypass flow path 108 to the gas outlet of adsorption tower A. At the same time, the dehumidified hydrogen gas is released from the gas outlet of adsorption tower B to the second release flow path 104, passes through the on-off valve VL8, flows through the junction 106 and the outlet path 100, and is discharged from the hydrogen outlet 120. The regenerated hydrogen gas that has absorbed moisture released from the adsorbent in adsorption tower A is discharged from the gas inlet of adsorption tower A and is discharged to the regenerated hydrogen outlet 130 through the first regenerated hydrogen discharge flow path 90. In this case, a throttle valve (not shown) may be provided in the outlet bypass flow path 108 to reduce the pressure of the hydrogen gas discharged from adsorption tower B before supplying it to adsorption tower A. This allows for even better regeneration of adsorption tower A.

[0063] Figure 2(d) shows the regeneration process in which dehumidified hydrogen gas is supplied from adsorption tower A (treatment adsorption tower) to adsorption tower B (regeneration adsorption tower), and the moisture contained in the adsorbent in adsorption tower B is released to regenerate adsorption tower B.

[0064] Specifically, the control device 30 opens valves VL1 and VL4 and closes valves VL2 and VL3. As a result, hydrogen gas introduced from the hydrogen booster stack 16 through the hydrogen inlet 110 into the inlet path 80 flows through the branch point 86 and the first supply flow path 82, passes through the on-off valve VL1, and is supplied to the gas inlet of the adsorption tower A. The hydrogen gas supplied to the adsorption tower A is dehumidified by coming into contact with the adsorbent contained inside the adsorption tower A.

[0065] Furthermore, the control device 30 opens valves VL7, VL9, and VL10 and closes valve VL8. As a result, dehumidified hydrogen gas is supplied from the gas outlet of adsorption tower A through the outlet bypass flow path 108 to the gas outlet of adsorption tower B. At the same time, the dehumidified hydrogen gas is released from the gas outlet of adsorption tower A into the first release flow path 102, passes through the on-off valve VL7, flows through the junction 106 and the outlet path 100, and is discharged from the hydrogen outlet 120. The regenerated hydrogen gas that has absorbed moisture released from the adsorbent in adsorption tower B is released from the gas inlet of adsorption tower B, passes through the second regenerated hydrogen discharge flow path 92, and is discharged from the regenerated hydrogen outlet 130. In this case, a throttle valve (not shown) may be provided in the outlet bypass flow path 108 to reduce the pressure of the hydrogen gas discharged from adsorption tower A before supplying it to adsorption tower B. This allows for further effective regeneration of adsorption tower B.

[0066] The control device 30 is composed of an ECU (Electronic Control Unit). The ECU is composed of a computer having one or more processors (CPUs), memory, input / output interfaces, and electronic circuits. The one or more processors (CPUs) execute programs (computer-executable instructions) (not shown) stored in memory. The control device 30 controls all aspects of the electrochemical hydrogen boosting system 10.

[0067] The operation of the electrochemical hydrogen boosting system 10 will be described with reference to FIG.

[0068] The control device 30 opens the raw hydrogen valve 52 provided in the raw hydrogen supply path 50 to supply raw hydrogen to the hydrogen supply device 14. The water content of the raw hydrogen supplied to the sealed container 44 of the hydrogen supply device 14 is adjusted, and the raw hydrogen is supplied as hydrogen gas to the hydrogen inlet PT1 of the hydrogen booster stack 16 via the hydrogen outlet 46 and the hydrogen supply path 60. Unused hydrogen gas discharged from the hydrogen outlet PT2 of the hydrogen booster stack 16 is circulated to the hydrogen circulation port 67 of the sealed container 44 via the hydrogen circulation path 62. The control device 30 controls the rotation speed of a circulation pump 66 provided in the hydrogen circulation path 62 to adjust the flow rate of the circulating hydrogen gas.

[0069] The hydrogen gas supplied to the hydrogen booster stack 16 is electrochemically boosted in pressure to become high-pressure hydrogen gas, which is then discharged from the high-pressure hydrogen outlet PT3 to the high-pressure hydrogen supply flow path 70. After liquid water is removed from the high-pressure hydrogen gas in the gas-liquid separator 18, the high-pressure hydrogen gas is supplied to the condenser 20. The high-pressure hydrogen gas dehumidified in the condenser 20 is supplied to the PSA unit 22. Next, the high-pressure hydrogen gas is further dehumidified in the PSA unit 22, and then supplied as dry high-pressure hydrogen gas via the high-pressure hydrogen discharge flow path 122 to a hydrogen tank or the like.

[0070] [Flowchart of electrochemical hydrogen boosting system] The operation procedures of the adsorption process and regeneration process of the electrochemical hydrogen boosting system 10 according to the embodiment will be described with reference to the flowcharts shown in FIGS.

[0071] In step S1, the control device 30 measures the dew point of moisture contained in the hydrogen gas released in the adsorption process using a dew point meter DP1 provided in the first release flow path 102 of the adsorption tower A of the PSA unit 22. The measured dew point is sent to the control device 30, which estimates the moisture content in the adsorption tower A based on the dew point. Note that in step S1, the PSA unit 22 performs the adsorption process shown in FIG. 2(a) as already described.

[0072] In step S2, the control device 30 determines whether the dew point measured by the dew point meter DP1 is equal to or greater than a predetermined value DP_H (upper dew point limit). If the determination result is affirmative (step S2: YES), the control device 30 proceeds to step S3. If the determination result is negative (step S2: NO), the control device 30 returns to step S1. Here, the predetermined value DP_H is set based on the upper limit of the moisture content that can be absorbed by the adsorbent filled in the adsorption tower 24. As the moisture content of the adsorbent increases, the amount of moisture that can be adsorbed decreases, and the dew point increases. The predetermined value DP_H is the dew point of hydrogen gas that is released when the moisture content of the adsorbent reaches the upper limit.

[0073] In this embodiment, the water content in the adsorbent is estimated from the dew point. However, instead of the dew point, the water content of the adsorbent may be estimated from the integrated flow rate of hydrogen gas, the flow time of hydrogen gas, the weight of the adsorption tower 24, etc., and a corresponding predetermined value may be set. Similarly, in the following description, instead of the dew point, physical quantities such as the integrated flow rate of hydrogen gas, the flow time of hydrogen gas, and the weight of the adsorption tower 24 may be used.

[0074] In step S3, the controller 30 controls each of the on-off valves VL1 to VL10 to switch from adsorption tower A to adsorption tower B. Specifically, as already described, the controller 30 switches from adsorption tower A to adsorption tower B by transitioning the PSA unit 22 from the state shown in Fig. 2(a) to the state shown in Fig. 2(b).

[0075] In step S4, the controller 30 controls each of the on-off valves VL1 to VL10 to start the regeneration process of the adsorption tower A. Specifically, as already described, the controller 30 starts the regeneration process of the adsorption tower A by transitioning the PSA unit 22 from the state shown in Figure 2(b) to the state shown in Figure 2(c).

[0076] In step S5, the controller 30 closes (turns OFF) the raw hydrogen valve 52 provided in the raw hydrogen supply line 50. This stops the supply of raw hydrogen to the hydrogen supply device .

[0077] In step S6, the control device 30 controls the pressure reducing valve 96 and the flow rate adjusting valve 98 to supply the regenerated hydrogen gas discharged from the regenerated hydrogen outlet 130 of the PSA unit 22 to the hydrogen supply device 14 via the return flow path 94. Next, the control device 30 supplies the regenerated hydrogen gas as hydrogen gas to the hydrogen booster stack 16, and supplies the high-pressure hydrogen gas discharged from the hydrogen booster stack 16 to the adsorption column B of the PSA unit 22 via the gas-liquid separator 18 and the condenser 20.

[0078] In step S7, the controller 30 measures the dew point of the regenerated hydrogen gas discharged from the adsorption tower A in the regeneration step using the dew point meter DP4 provided in the return flow path 94.

[0079] In step S8, the control device 30 determines whether the dew point measured by the dew point meter DP4 is lower than a predetermined value DP_L (lower limit dew point). If the determination result is affirmative (step S8: YES), the control device 30 proceeds to step S9. If the determination result is negative (step S8: NO), the control device 30 returns to step S7. Here, the predetermined value DP_L is set based on the water content of the adsorbent. When the dew point measured by the dew point meter DP4 falls to the predetermined value DP_L as the water content of the adsorbent decreases, the control device 30 determines that the water contained in the adsorbent has been sufficiently released, proceeds to step S9, and the regeneration process of the adsorption tower A is completed.

[0080] In step S10, the controller 30 controls each of the on-off valves VL1 to VL10 to start the adsorption process in the adsorption tower B. Specifically, as already described, the controller 30 performs the adsorption process in the adsorption tower B by transitioning the PSA unit 22 from the state shown in Fig. 2(c) to the state shown in Fig. 2(b).

[0081] In step S11, the controller 30 opens (ON) the raw hydrogen valve 52 provided in the raw hydrogen supply line 50. This starts the supply of raw hydrogen to the hydrogen supply device .

[0082] In step S12, the control device 30 measures the dew point of moisture contained in the hydrogen gas released in the adsorption step using a dew point meter DP2 provided in the second release line 104 of the adsorption tower B of the PSA unit 22. The measured dew point is sent to the control device 30, which estimates the moisture content contained in the adsorption tower B based on the dew point. In step S12, the PSA unit 22 performs the adsorption step shown in FIG. 2(b) as already described.

[0083] In step S13, similar to step S2, the control device 30 determines whether the dew point measured by the dew point meter DP2 is equal to or greater than a predetermined value DP_H (upper dew point limit). If the determination result is affirmative (step S13: YES), the control device 30 proceeds to step S14. If the determination result is negative (step S13: NO), the control device 30 returns to step S12. Here, the predetermined value DP_H is set similarly to step S2.

[0084] The predetermined dew point values ​​(DP_H, DP_L) may be set to different values ​​for adsorption tower A and adsorption tower B. Also, even if physical quantities such as the cumulative flow rate of hydrogen gas, the flow time of hydrogen gas, or the weight of adsorption tower 24 are used instead of the dew point, different predetermined values ​​(upper limit and lower limit) may be set for adsorption tower A and adsorption tower B.

[0085] In step S14, the controller 30 controls each of the on-off valves VL1 to VL10 to switch from adsorption tower B to adsorption tower A. Specifically, as already described, the controller 30 switches from adsorption tower B to adsorption tower A by shifting the PSA unit 22 from the state shown in Figure 2(b) to the state shown in Figure 2(a).

[0086] In step S15, the controller 30 controls each of the on-off valves VL1 to VL10 to start the regeneration process of the adsorption tower B. Specifically, as already described, the controller 30 starts the regeneration process of the adsorption tower B by transitioning the PSA unit 22 from the state shown in Fig. 2(a) to the state shown in Fig. 2(d).

[0087] In step S16, the controller 30 closes the raw hydrogen valve 52 provided in the raw hydrogen supply line 50. This stops the supply of raw hydrogen to the hydrogen supply device .

[0088] In step S17, the control device 30 controls the pressure reducing valve 96 and the flow rate adjusting valve 98 to supply the regenerated hydrogen gas discharged from the regenerated hydrogen outlet 130 of the PSA unit 22 to the hydrogen supply device 14 via the return flow path 94. Next, the control device 30 supplies the regenerated hydrogen gas as hydrogen gas to the hydrogen booster stack 16, and supplies the high-pressure hydrogen gas discharged from the hydrogen booster stack 16 to the adsorption column B of the PSA unit 22 via the gas-liquid separator 18 and the condenser 20.

[0089] In step S18, the controller 30 measures the dew point of the regenerated hydrogen gas discharged from the adsorption tower B in the regeneration step using the dew point meter DP4 provided in the return flow path 94.

[0090] In step S19, the control device 30 determines whether the dew point measured by the dew point meter DP4 is lower than a predetermined value DP_L (dew point lower limit). If the determination result is affirmative (step S19: YES), the control device 30 proceeds to step S20. If the determination result is negative (step S19: NO), the control device 30 returns to step S18. Here, the predetermined value DP_L is set in the same manner as in step S8. The control device 30 proceeds to step S20, and the regeneration process of the adsorption tower B is completed.

[0091] In step S21, the controller 30 controls each of the on-off valves VL1 to VL10 to start the adsorption process in the adsorption tower A. Specifically, as already described, the controller 30 performs the adsorption process in the adsorption tower A by transitioning the PSA unit 22 from the state shown in Fig. 2(d) to the state shown in Fig. 2(a).

[0092] In step S22, the controller 30 opens (ON) the raw hydrogen valve 52 provided in the raw hydrogen supply line 50. This starts the supply of raw hydrogen to the gas-liquid separator .

[0093] [Timing chart] A time chart relating to adsorption tower A, adsorption tower B, and the supply of raw hydrogen according to this embodiment will be explained with reference to Fig. 5. This timing chart explains the adsorption process and regeneration process described in Fig. 2(a) to Fig. 2(d) and the flowcharts described in Fig. 3 and Fig. 4 on the time axis.

[0094] At time t0, the control device 30 causes the adsorption tower A to start the adsorption process. The adsorption tower A dehumidifies the moisture contained in the hydrogen gas and outputs dried hydrogen gas. Inside the PSA unit 22, hydrogen gas flows as shown by the arrows in FIG. 2(a). In this case, the control device 30 performs a standby process on the adsorption tower B, and no hydrogen gas is supplied to the adsorption tower B. The raw hydrogen is supplied from the hydrogen supply device 14 to the hydrogen booster stack 16, and the pressurized high-pressure hydrogen gas is supplied to the adsorption tower A.

[0095] At time t1, the control device 30 starts a dew point measurement process in which the dew point of the hydrogen gas is measured using the dew point meter DP1 (step S1). Time t1 is set after a predetermined time T1 has elapsed since time t0. The predetermined time T1 is the time until the water content of the adsorbent contained in the adsorption tower A approaches approximately its upper limit. This predetermined time T1 is set in advance through experiments. Note that the dew point measurement process may be started simultaneously with the start of the adsorption process in the adsorption tower A, without waiting for the predetermined time T1 to elapse.

[0096] At time t2, the control device 30 determines that the dew point measured by the dew point meter DP1 has become greater than the predetermined value DP_H (step S2: YES). Next, the control device 30 switches from adsorption tower A to adsorption tower B (see step S3). That is, instead of adsorption tower A, adsorption tower B dehumidifies the moisture contained in the high-pressure hydrogen gas supplied from the hydrogen booster stack 16 and outputs dried hydrogen gas. Inside the PSA device 22, hydrogen gas flows as shown by the arrows in FIG. 2(b).

[0097] After switching from adsorption tower A to adsorption tower B, the control device 30 starts the regeneration process of adsorption tower A (step S4). Dried hydrogen gas is supplied from adsorption tower B to adsorption tower A, and adsorption tower A is regenerated. Hydrogen gas flows inside the PSA unit 22 as shown by the arrows in FIG. 2(c). In this case, the control device 30 stops the supply of raw hydrogen (step S5). The control device 30 supplies the regenerated hydrogen gas discharged from the PSA unit 22 to the hydrogen supply device 14. Next, the control device 30 supplies the regenerated hydrogen gas as hydrogen gas to the hydrogen booster stack 16, and supplies the high-pressure hydrogen gas derived from the hydrogen booster stack 16 to adsorption tower B of the PSA unit 22.

[0098] At time t3, the control device 30 starts a dew point measurement process in which the dew point of the hydrogen gas is measured using the dew point meter DP4 (step S7). Time t3 is set after a predetermined time T2 has elapsed since time t2. The predetermined time T2 is the time required for the water content of the adsorbent contained in the adsorption tower A to roughly approach a lower limit. This predetermined time T2 is set in advance through experiments. Note that the dew point measurement process may be started simultaneously with the start of the regeneration process by the adsorption tower A, without waiting for the predetermined time T2 to elapse.

[0099] At time t4, when the control device 30 determines that the dew point measured by the dew point meter DP3 has become lower than the predetermined value DP_L (step S8: YES), the regeneration process of adsorption tower A is completed (step S9). As a result, the supply of hydrogen gas from adsorption tower B to adsorption tower A is stopped. The control device 30 starts the adsorption process by adsorption tower B (step S10). Hydrogen gas flows inside the PSA device 22 as shown by the arrows in FIG. 2(b). In this case, the control device 30 starts the supply of raw hydrogen (step S11). The supplied raw hydrogen gas has its moisture content adjusted by the hydrogen supply device 14 and is then supplied as hydrogen gas to the hydrogen booster stack 16. The control device 30 supplies the high-pressure hydrogen gas pressurized by the hydrogen booster stack 16 to adsorption tower B. Adsorption tower A performs a standby process.

[0100] At time t5, the control device 30 starts the dew point measurement process using the dew point meter DP2 (see step S12). Time t5 is set after a predetermined time T1 has elapsed since time t4. The predetermined time T1 is the time when the adsorption tower B The predetermined time T1 is the time until the water content of the adsorbent contained in the adsorbent approaches approximately the upper limit value. This predetermined time T1 is set in advance through experiments. Note that the dew point measurement process may be started simultaneously with the start of the adsorption process in the adsorption tower B, without waiting for the lapse of the predetermined time T1.

[0101] At time t6, the control device 30 determines that the dew point measured by the dew point meter DP2 has become greater than the predetermined value DP_H (step S13: YES). Next, the control device 30 switches from adsorption tower B to adsorption tower A (step S14). That is, instead of adsorption tower B, adsorption tower A dehumidifies the moisture contained in the high-pressure hydrogen gas supplied from the hydrogen booster stack 16 and outputs dried hydrogen gas. Inside the PSA device 22, hydrogen gas flows as shown by the arrows in FIG. 2(a).

[0102] After switching from adsorption tower B to adsorption tower A, the control device 30 starts the regeneration process of adsorption tower B (step S15). Dried hydrogen is supplied from adsorption tower A to adsorption tower B, and adsorption tower B is regenerated. Hydrogen gas flows inside the PSA unit 22 as shown by the arrows in FIG. 2(d). In this case, the control device 30 stops the supply of raw hydrogen (step S16). The control device 30 supplies the regenerated hydrogen gas discharged from the PSA unit 22 to the hydrogen supply device 14. Next, the control device 30 supplies the regenerated hydrogen gas as hydrogen gas to the hydrogen booster stack 16, and supplies the high-pressure hydrogen gas derived from the hydrogen booster stack 16 to adsorption tower A of the PSA unit 22.

[0103] At time t7, the control device 30 starts a dew point measurement process in which the dew point meter DP4 measures the dew point of the hydrogen gas (see step S18). Time t7 is set after a predetermined time T2 has elapsed since time t6. The predetermined time T2 is the time required for the water content of the adsorbent contained in the adsorption tower B to roughly approach a lower limit value. This predetermined time T2 is set in advance through experiments. Note that the dew point measurement process may be started simultaneously with the start of the regeneration process in the adsorption tower B, without waiting for the predetermined time T2 to elapse.

[0104] At time t8, when the controller 30 determines that the dew point measured by the dew point meter DP4 has become lower than the predetermined value DP_L (step S19: YES), the regeneration process of adsorption tower B is completed (step S20). As a result, the supply of hydrogen gas from adsorption tower A to adsorption tower B is stopped. The controller 30 starts the adsorption process by adsorption tower A (step S21). Hydrogen gas flows inside the PSA unit 22 as shown by the arrows in FIG. 2(a). In this case, the controller 30 starts the supply of raw hydrogen (step S22). The supplied raw hydrogen gas has its moisture content adjusted by the hydrogen supply unit 14 and is then supplied as hydrogen gas to the hydrogen booster stack 16. The controller 30 supplies the high-pressure hydrogen gas pressurized by the hydrogen booster stack 16 to the adsorption tower A.

[0105] The operation at time t9 is the same as the operation at time t1 (step S1), and the operation at time t10 is the same as the operation at time t2, so detailed explanations of the subsequent timings will be omitted.

[0106] The following additional notes are further disclosed regarding the above embodiment.

[0107] (Appendix 1) The electrochemical hydrogen boosting system (10) of the present disclosure has a single cell (32) including an electrolyte membrane (34), an anode electrode (36) provided on one side of the electrolyte membrane, and a cathode electrode (40) provided on the other side of the electrolyte membrane, and is equipped with a hydrogen boosting stack (16) that supplies hydrogen gas to the anode electrode and releases pressurized high-pressure hydrogen gas from the cathode electrode, a power supply device (28) that applies voltage to the hydrogen boosting stack, a hydrogen supply device (14) that supplies hydrogen gas to the hydrogen boosting stack via a hydrogen supply flow path (60), and a PSA device (22) having multiple adsorption towers (24) (adsorption tower A, adsorption tower B) that dehumidify the high-pressure hydrogen gas released from the hydrogen boosting stack, and a return flow path (94) that returns the regenerated hydrogen gas used to regenerate the adsorption towers to the hydrogen supply flow path of the hydrogen boosting stack or the hydrogen supply device.

[0108] As a result, the regenerated hydrogen gas used for regeneration is returned to the hydrogen supply line or hydrogen supply device of the hydrogen booster stack via the return line, so the hydrogen gas is circulated and reused within the electrochemical hydrogen booster system and is not discharged to the outside. This increases the hydrogen gas utilization efficiency and prevents a decrease in the hydrogen production efficiency of the electrochemical hydrogen booster system. Furthermore, because the hydrogen gas used to regenerate the adsorption tower is not discharged to the outside, no special equipment is required for discharge, making the configuration of the electrochemical hydrogen booster system simpler and more economical.

[0109] (Appendix 2) In the electrochemical hydrogen boosting system described in Appendix 1, the plurality of adsorption towers (adsorption tower A, adsorption tower B) may include a treatment adsorption tower that dehumidifies hydrogen gas and a regeneration adsorption tower that releases adsorbed moisture, and when regenerating the regeneration adsorption tower, the dehumidified hydrogen gas may be supplied from the treatment adsorption tower to the regeneration adsorption tower, and the regeneration adsorption tower may be caused to release the adsorbed moisture, thereby regenerating the regeneration adsorption tower.

[0110] This allows one adsorption tower, whose adsorbent has reached its upper limit of moisture content, to be regenerated using dried hydrogen gas discharged from the other adsorption tower in the PSA unit. Therefore, there is no need to install special equipment to regenerate the adsorption tower, simplifying the configuration of the electrochemical hydrogen boosting system and making it more economical.

[0111] (Appendix 3) In the electrochemical hydrogen boosting system described in Appendix 1, the hydrogen boosting stack and the PSA device may be connected by a high-pressure hydrogen supply passage (70), and a gas-liquid separator (18) may be provided in the high-pressure hydrogen supply passage.

[0112] This allows liquid water to be effectively separated and removed from the high-pressure hydrogen gas before it is supplied to the PSA unit. This reduces the amount of water removed by the PSA unit, extending the time until the water content in the adsorption tower reaches its upper limit. This improves the availability of the adsorption tower.

[0113] (Appendix 4) In the electrochemical hydrogen boosting system described in Supplementary Note 1, the return passage may be provided with a pressure reducing valve (96) that reduces the pressure of the regenerated hydrogen gas flowing through it.

[0114] This makes it possible to adjust the pressure of the regenerated hydrogen gas supplied from the return flow path to the hydrogen booster stack via the hydrogen supply device, thereby making it possible to supply hydrogen gas at an optimum pressure to the hydrogen booster stack.

[0115] (Appendix 5) In the electrochemical hydrogen boosting system described in Appendix 1, the return flow path may be provided with a flow control valve (98) that adjusts the flow rate of the circulating regenerated hydrogen gas, and the flow control valve may adjust the flow rate of the circulating regenerated hydrogen gas based on the internal pressure of the sealed container (44) of the hydrogen supply device.

[0116] This allows an appropriate amount of regenerated hydrogen gas to be supplied to the hydrogen booster stack in accordance with the flow rate of high-pressure hydrogen gas released from the hydrogen booster stack, thereby optimizing the operation of the hydrogen booster stack.

[0117] (Appendix 6) In the electrochemical hydrogen boosting system described in Appendix 1, the hydrogen release port provided at the downstream end of the return flow path may open into liquid water stored in a sealed container of the hydrogen supply device.

[0118] This makes it possible to remove liquid droplets contained in the hydrogen gas supplied from the return flow path, and also to effectively adjust the humidity of the hydrogen gas supplied to the hydrogen booster stack by using liquid water.

[0119] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. [Explanation of symbols]

[0120] 10...Electrochemical hydrogen boosting system 12...Electrochemical hydrogen boosting device 14...Hydrogen supply device 16...Hydrogen booster stack 18...Gas-liquid separator 20...Condenser 22...PSA device 24...Adsorption tower 28...power supply unit 30...control unit 32...Single cell 34...Electrolyte membrane 36...Anode electrode 40...Cathode electrode 44...sealed container 50...raw material hydrogen supply path 60...hydrogen supply passage 70...high-pressure hydrogen supply passage 80...inlet passage 90...first recycled hydrogen discharge passage 92... Second regenerated hydrogen discharge flow path 94... Return flow path 100: Outlet path 110: Hydrogen inlet 120...Hydrogen outlet 130...Regenerated hydrogen outlet

Claims

1. a hydrogen pressurization stack having a unit cell including an electrolyte membrane, an anode electrode provided on one side of the electrolyte membrane, and a cathode electrode provided on the other side of the electrolyte membrane, the hydrogen pressurization stack supplying hydrogen gas to the anode electrode and releasing pressurized high-pressure hydrogen gas from the cathode electrode; a power supply device that applies a voltage to the hydrogen boosting stack; a hydrogen supply device that supplies hydrogen gas to the hydrogen boosting stack through a hydrogen supply passage; a PSA device having a plurality of adsorption towers for dehumidifying the high-pressure hydrogen gas released from the hydrogen boosting stack; Equipped with a return flow path for returning the regenerated hydrogen gas used for regenerating the adsorption tower to the hydrogen supply device of the hydrogen boosting stack; The hydrogen supply device includes a sealed container in which liquid water is stored downward in the direction of gravity; a pressure sensor that measures the pressure of hydrogen gas contained in a space formed above the liquid water in the sealed container, a hydrogen release port provided at a downstream end of the return flow path opens into the liquid water, and the regenerated hydrogen gas released from the hydrogen release port reaches the space above the liquid water; The return flow path is provided with a flow rate control valve that adjusts the flow rate of the recycled hydrogen gas flowing through it; The flow rate control valve adjusts the flow rate of the recycled hydrogen gas based on the pressure of the hydrogen gas contained in the space detected by the pressure sensor. Electrochemical hydrogen boosting system.

2. 2. The electrochemical hydrogen boosting system according to claim 1, The plurality of adsorption towers include a treatment adsorption tower that dehumidifies hydrogen gas and a regeneration adsorption tower that releases adsorbed moisture, and when regenerating the regeneration adsorption tower, the dehumidified hydrogen gas is supplied from the treatment adsorption tower to the regeneration adsorption tower, and the regeneration adsorption tower releases the adsorbed moisture, thereby regenerating the regeneration adsorption tower. Electrochemical hydrogen boosting system.

3. 2. The electrochemical hydrogen boosting system according to claim 1, the hydrogen boosting stack and the PSA device are connected by a high-pressure hydrogen supply passage, and a gas-liquid separator is provided in the high-pressure hydrogen supply passage; Electrochemical hydrogen boosting system.

4. 2. The electrochemical hydrogen boosting system according to claim 1, The return flow path is provided with a pressure reducing valve that reduces the pressure of the circulating regenerated hydrogen gas. Electrochemical hydrogen boosting system.

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