Hydrogen production device

Abstract

To provide a hydrogen production device which can improve the production efficiency of hydrogen at low cost.SOLUTION: A hydrogen production device 1 reacts a plurality of metal pieces including aluminum or an aluminum alloy with reaction liquid L including a strongly alkaline aqueous solution to produce hydrogen. The hydrogen production device 1 includes: a reaction tank 10; a metal piece housing part 20 which is provided in the reaction tank 10 and which has a plurality of housing regions 21 for housing a different one of the plurality of metal pieces that are divided from one another; a reaction liquid supply part which supplies the reaction liquid L to the reaction tank 10 in a state where the metal piece housing part 20 is placed in the reaction tank 10; and a control part which controls the amount and the concentration of the reaction liquid supplied to the reaction tank according to the amount of the metal pieces housed in the metal piece housing part 20 while controlling supply of the reaction liquid L so that the metal pieces react with the reaction liquid L one by one in the respective housing regions 21.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a hydrogen generation device. [Background technology]

[0002] Patent Document 1 discloses a hydrogen generator that generates hydrogen by reacting aluminum with an aqueous NaOH solution, in which aluminum chips are sequentially introduced into a large, sealed reaction vessel in which an aqueous NaOH solution has been stored in advance, and the generated hydrogen is then recovered. Another known hydrogen generator is one that sequentially introduces an aqueous NaOH solution into a small, sealed reaction vessel in which aluminum chips and water have been previously introduced, and the generated hydrogen is then recovered.

[0003] Because hydrogen gas is highly reactive, the reaction must be carried out in a sealed reactor, so a pressure vessel that can withstand high internal pressure is used as the reactor. In addition, because the reaction between aluminum and an aqueous NaOH solution is an exothermic reaction, thermal runaway caused by excessive heat generation must be suppressed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-169390 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the configuration disclosed in Patent Document 1 uses a large reaction tank to efficiently recover hydrogen gas, which results in high costs for maintaining the reaction tank. Furthermore, the configuration disclosed in Patent Document 1 involves introducing aluminum chips into an NaOH-rich environment, and since a large amount of highly concentrated NaOH aqueous solution is used, thermal runaway is likely to occur. Therefore, the configuration is equipped with a cooling device and an agitator for agitating the aqueous solution in the reaction tank to prevent bumping due to a sudden reaction between the aluminum chips supplied to the reaction tank and the reaction solution. This results in a large-scale device and high equipment costs.

[0006] On the other hand, the hydrogen generation device with the other configuration described above uses a small reaction vessel, which reduces the cost of maintaining the reaction vessel. Furthermore, because NaOH is sequentially added to an aluminum-rich environment, thermal runaway is unlikely to occur, eliminating the need for a stirrer. However, with this configuration, it was found that the amount of hydrogen gas generated was significantly lower than the theoretical value. This was because the aluminum concentration in the reaction solution after the reaction was completed was high. It was inferred that in an aluminum-rich environment, some of the aluminum did not react with the supplied NaOH, but remained in the reaction solution in an ionic state, and did not contribute to the generation of hydrogen gas. Therefore, there is room for improvement in efficiently generating hydrogen.

[0007] An object of the present invention is to provide a hydrogen generation device that can improve the efficiency of hydrogen generation at low cost. [Means for solving the problem]

[0008] One aspect of the present invention is A hydrogen generation device that generates hydrogen by reacting a plurality of metal pieces including aluminum or an aluminum alloy with a reaction solution consisting of a strong alkaline aqueous solution, A reaction vessel; a metal piece storage unit provided in the reaction tank and having a plurality of storage areas for storing the plurality of metal pieces in a separated manner; a reaction liquid supply unit that supplies the reaction liquid to the reaction tank while the metal piece storage unit is installed in the reaction tank; a control unit that controls the amount and concentration of the reaction solution supplied to the reaction tank according to the amount of the metal pieces stored in the metal piece storage unit, and controls the supply of the reaction solution so that the metal pieces react with the reaction solution in each storage area in sequence; The hydrogen generating device includes: [Effects of the Invention]

[0009] According to the hydrogen generation apparatus of the above aspect, metal pieces containing aluminum or an aluminum alloy are stored in a metal piece storage section provided in a reaction vessel, separated into multiple storage areas. The amount and concentration of the reaction solution, which is a strong alkaline aqueous solution, supplied to the reaction vessel is set according to the amount of metal pieces, and the reaction solution is supplied to the reaction vessel so that the metal pieces react with the reaction solution sequentially in each storage area. Therefore, compared to when the reaction solution is supplied to the entire metal pieces, the amount of metal pieces contributing to a single reaction can be reduced, thereby suppressing the sudden generation of reaction heat. Therefore, a cooling device or agitator to suppress thermal runaway is not required, thereby reducing equipment costs.

[0010] Furthermore, in the above embodiment, the reaction between aluminum and the reaction solution can proceed in a strong alkali-rich environment, so that the entire amount of aluminum can be used for hydrogen generation, improving the efficiency of hydrogen generation. Furthermore, the improved efficiency of hydrogen generation allows a sufficient amount of hydrogen to be generated even when a relatively small reaction vessel is used, so that the use of a small reaction vessel can reduce the maintenance costs of the reaction vessel.

[0011] As described above, according to the above aspect, it is possible to provide a hydrogen generation device that can improve the efficiency of hydrogen generation at low cost. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a conceptual diagram showing the configuration of a hydrogen generation device in a first embodiment. [Figure 2] FIG. 2 is a longitudinal cross-sectional view of a reaction vessel according to the first embodiment. [Figure 3] FIG. 2 is a top view of the reaction vessel in the first embodiment with the lid open. [Figure 4] FIG. 2 is a side perspective view of a metal piece storage section in the first embodiment. [Figure 5] 3 is a partially enlarged vertical cross-sectional view of a metal piece storage section in the first embodiment. [Figure 6] FIG. 2 is a vertical cross-sectional view of the reaction tank in a first state to which a reaction liquid has been supplied in the first embodiment. [Figure 7] FIG. 3 is a longitudinal cross-sectional view of the reaction tank in a second state to which a reaction liquid has been supplied in the first embodiment. [Figure 8] FIG. 1 is a perspective transparent view of a reaction vessel in variant form 1. [Figure 9] FIG. 10 is a partially enlarged vertical cross-sectional view of a metal piece storage section in the first modified embodiment. [Figure 10] (a) A longitudinal cross-sectional view of the reaction vessel and (b) a perspective view of the storage area in variant 2. [Figure 11] FIG. 10 is a cross-sectional perspective view of a reaction vessel in variant 3. DETAILED DESCRIPTION OF THE INVENTION

[0013] (Embodiment 1) 1. Hydrogen generator 1 The hydrogen generator 1 of the present embodiment 1 will be described in detail below. The hydrogen generator 1 of the present embodiment 1 shown in Fig. 1 generates hydrogen by reacting a plurality of metal pieces M containing aluminum or an aluminum alloy with a reaction liquid L made of a strong alkaline aqueous solution.

[0014] 1, the hydrogen generator 1 includes a reaction vessel 10, a metal piece storage unit 20, a reaction liquid supply unit 30, a control unit 40, a gas replacement unit 50, a hydrogen recovery unit 60, and a by-product recovery unit 70. Each component will be described in detail below.

[0015] 2. Reactor 10 The reaction vessel 10 is a pressure vessel in which metal pieces M are reacted with a reaction liquid L, and is configured to be sealable. The capacity of the reaction vessel 10 is not limited, but is preferably less than 20 L. By making the reaction vessel 10 a relatively small pressure vessel of less than 20 L, the cost of maintaining the reaction vessel 10 in accordance with standards set by laws and regulations can be reduced. In the first embodiment, as shown in FIG. 2, the reaction vessel 10 is composed of a bottomed cylindrical main body 10a and a lid 10b. The lid 10b is detachably attached to the upper opening of the main body 10a, and the interior of the reaction vessel 10 is sealed by attaching the lid 10b to the main body 10a.

[0016] As shown in Figures 2 and 3, the reaction vessel 10 has a basket-shaped member 11 inside. The basket-shaped member 11 is cylindrical with a bottom, and the sides and bottom are mesh-like. A pair of foldable handles 12 are provided at the upper end of the basket-shaped member 11. The basket-shaped member 11 is placed on a step 13 formed on the bottom inside the reaction vessel 10, and can be removed from an opening at the upper end of the main body 10a of the reaction vessel 10 via the handles 12. A metal piece storage unit 20, which will be described later, is placed inside the basket-shaped member 11.

[0017] The reaction vessel 10 is equipped with a reaction liquid supply passage 14, a gas discharge passage 15, a by-product discharge section 16, a purge passage 17, a liquid level sensor 18, and a temperature sensor 19. The reaction liquid supply passage 14 is a passage for supplying the reaction liquid L into the reaction vessel 10 and is connected to a reaction liquid supply section 30 described later. The gas discharge passage 15 is a passage for extracting hydrogen gas generated in the reaction vessel 10 to the outside and is connected to a hydrogen recovery section 60 described later. The by-product discharge section 16 is a passage for extracting by-products generated in the reaction vessel 10 and is connected to a by-product recovery section 70 described later. The purge passage 17 is a passage for supplying an inert gas to replace the gas phase in the reaction vessel 10 with an inert gas and is connected to a gas replacement section 50 described later.

[0018] The liquid level sensor 18 detects whether the liquid level of the reaction liquid L in the reaction tank 10 has reached a reference value. The temperature sensor 19 detects the temperature of the reaction liquid L in the reaction tank 10. The detection results of the liquid level sensor 18 and the temperature sensor 19 are transmitted to the control unit 40, which will be described later.

[0019] 3. Metal piece storage section 20 As shown in Figures 2 and 3, the metal piece storage section 20 is provided in the reaction vessel 10, and as shown in Figures 2 and 4, it has a plurality of storage areas 21. The plurality of storage areas 21 are configured to store a plurality of metal pieces M in a separated manner. The configuration of the plurality of storage areas 21 is not limited, and various configurations can be adopted. For example, in this embodiment 1, as shown in Figures 2 and 4, the plurality of storage areas 21 are formed by stacking six bottomed cylindrical dish members 21a to 21f in the vertical direction Y. Three spacers 22 are provided on each of the dish members 21a to 21f so that separation areas 23 (23a to 23f) are formed between adjacent dish members 21a to 21f and between the dish members 21a to 21f and the bottom of the basket-shaped member 11, separating them from each other in the vertical direction Y. By providing the separation areas 23 (23a to 23f), even if a portion of the reaction liquid L is scattered upward due to a reaction in the lower tray member 21a, the scattered portion of the reaction liquid L can be prevented from reaching the metal pieces M in the tray members 21b to 21f located above. The size of the separation areas 23a to 23f in the vertical direction Y is not limited, but can be set to be equal to the height H1 of each tray member 21a to 21f. As shown in FIG. 5, the metal pieces M are stored in the tray members 21a and 21b.

[0020] The metal piece M is not limited as long as it contains aluminum or an aluminum alloy, and may contain a material other than aluminum. In this embodiment, ADC12, an Al-Si-Cu alloy, is used as the metal piece M.

[0021] The amount of metal pieces M stored in the multiple storage areas 21a-21f is not limited, and the total amount of metal pieces M may be distributed evenly among the multiple storage areas 21a-21f, or may be distributed at a predetermined gradient. For example, if the metal pieces M are distributed evenly among the multiple storage areas 21a-21f, there is no need to change the amount of metal pieces M for each storage area 21a-21f, improving workability. Furthermore, the amount of metal pieces M distributed can be increased toward the lower storage areas 21a-21f. In this case, since less heat is generated at the beginning of the reaction, increasing the amount of metal pieces M involved in the reaction can shorten the overall time until the reaction is completed. In this embodiment 1, the amount of metal pieces M stored in each of the multiple storage areas 21a-21f is distributed evenly.

[0022] 4. Reaction liquid supply unit 30 As described above, the reaction liquid supply unit 30 shown in FIG. 1 supplies the reaction liquid L to the reaction tank 10 via the reaction liquid supply passage 14 provided in the reaction tank 10. The reaction liquid L is stored in the reaction liquid supply unit 30. The reaction liquid L may be any strong alkaline aqueous solution, and in the first embodiment, an NaOH aqueous solution is used. The concentration of the NaOH aqueous solution is not limited and is set by the control unit 40 described below, but can be within the range of 3 to 12%, for example.

[0023] 5. Control unit 40 1 sets the amount and concentration of the reaction liquid L in the reaction liquid supply unit 30 and controls the supply of the reaction liquid L to the reaction tank 10. In the present embodiment 1, the aluminum contained in the metal piece M and the NaOH aqueous solution that constitutes the reaction liquid L undergo a reaction according to the following formula (1).

[0024]

number

[0025] Based on the above formula (1), the control unit 40 obtains the total amount of metal pieces M stored in the metal piece storage unit 20, and sets the amount and concentration of the reaction liquid L in the reaction liquid supply unit 30 so that the molar ratio of the metal pieces M to the reaction liquid L is 1:1 or more. This makes it possible to use the entire amount of metal pieces M stored in the metal piece storage unit 20 for hydrogen generation.

[0026] For example, in the first embodiment, when a reaction tank 10 with a capacity of 20 L is used, the total amount of aqueous NaOH solution that can be added to the reaction tank 10 is 11.4 L. The theoretical amount of 12.8% aqueous NaOH solution required to react 50 g of metal pieces M is 0.39 L, and therefore, under conditions where the molar ratio with the 12.8% aqueous NaOH solution L is 1:1, the amount of metal pieces M is approximately 1461 g. Therefore, the total amount of metal pieces M stored in the metal piece storage unit 20 can be set to approximately 1461 g or less, and the maximum amount of 12.8% aqueous NaOH solution L that can be added to the reaction tank 10 can be sequentially added to the 20 L reaction tank 10.

[0027] The control unit 40 controls the operation of the pump 31 and the diaphragm valve 32 connected to the reaction liquid supply unit 30, thereby controlling the supply of the reaction liquid L so that the metal pieces M react with the reaction liquid L in each of the storage areas 21a to 21f. That is, by supplying the reaction liquid L to the reaction tank 10, the control unit 40 causes the water level LH1 of the reaction liquid L to reach the first storage area 21a, as shown in FIG. 6, thereby creating a first state in which the metal pieces M in the first storage area 21a react with the reaction liquid L. In this first state, the metal pieces in the second storage area 21b, which is located vertically above the first storage area 21a, do not react with the reaction liquid.

[0028] 7, the reaction liquid L is further supplied to the reaction vessel 10 by the control unit 40, so that the water level LH2 of the reaction liquid L reaches the second storage area 21b, thereby achieving a second state in which both the metal pieces M in the first storage area 21a and the metal pieces M in the second storage area 21b are reacting with the reaction liquid L. Similarly, by further supplying the reaction liquid L by the control unit 40, the metal pieces M stored in the third to sixth storage areas 21c, 21d, 21e, and 21f, which are located further vertically upward, can be similarly sequentially brought into a state in which they are reacting with the reaction liquid L.

[0029] The timing of the transition from the first state to the second state by the control unit 40 can be set as appropriate, and for example, the supply of the reaction liquid can be controlled so that the transition from the first state to the second state occurs after the first state has been maintained for a predetermined period of time. The period during which the first state is maintained can be, for example, the period until the reaction between the reaction liquid L and a predetermined amount or all of the metal pieces M present in the first storage area 21a is completed.

[0030] 6. Gas replacement unit 50 The gas replacement unit 50 shown in Fig. 1 replaces the gas phase in the sealed reaction vessel 10 with a gas inert to hydrogen. The gas replacement by the gas replacement unit 50 is performed by controlling the operation of a pump 51 and a diaphragm valve 52 connected to the gas replacement unit 50 using the control unit 40. This can be performed before the start of the reaction in the reaction vessel 10. Any known gas can be used as the gas inert to hydrogen, and nitrogen gas is used in the first embodiment.

[0031] The by-product recovery section 70 shown in FIG. 1 recovers by-products generated in the reaction tank 10 by the reaction between the metal pieces M and the reaction liquid L. In the first embodiment, aluminum hydroxide can be recovered as a by-product, as shown in the above formula (1). Most of the aluminum hydroxide produced can be recovered in a solid state, but some of it dissolves in the reaction liquid after the reaction is completed. In addition, products generated by the reaction between substances other than aluminum contained in the metal pieces M and the reaction liquid L can also be recovered as by-products. For example, Na2SiO3, which is a reaction product of Si and an aqueous NaOH solution, can be recovered as a by-product. The recovered by-products can be used as resources depending on their type.

[0032] 7. Modifications of the metal piece storage section 20 In this embodiment, the metal piece storage section 20 is not limited to this configuration and can employ various other configurations. For example, it may be rectangular dish members 21a, 21b, etc., as shown in modified embodiment 1 in Figures 8 and 9. The dish members 21a, 21b, etc., in modified embodiment 1, all have the same shape, and their bottoms are formed with mesh 25, allowing the reaction liquid L and the generated hydrogen gas to flow through. As shown in Figure 9, the bottom of the dish member 21b has legs 24 at the four corners that abut the inner surface of the upper opening of the lower dish member 21a. In these rectangular dish members 21a, 21b, the metal pieces M can be stored up to a height approximately half the height H1 of the dish members 21a, 21b, thereby maintaining the separation region 23b.

[0033] Alternatively, the metal piece storage section 20 may have cylindrical members 21a, 21b, etc., as in modified embodiment 2 shown in Figure 10(b). As shown in Figure 10(b), the cylindrical members 21a, 21b, etc. have a hexagonal prism-like outer shape, an internal space extending in the axial direction, and an open axial end. The cylindrical members 21a, 21b, etc. are stacked closely together in the vertical and horizontal directions within the reaction vessel 10, with the axial direction of the cylindrical members 21a, 21b, etc. aligned horizontally. This allows the metal pieces M to be stored in the hollow portion of each cylindrical member.

[0034] Furthermore, the metal piece storage section 20 may have tray members 21a, 21b, etc. that are continuous like a spiral staircase, as in modified embodiment 3 shown in Figure 11. In this case, since the tray members 21a, 21b, etc. are continuous, the metal pieces M stored in the tray members 21a, 21b, etc. can be reacted continuously as the water level of the reaction liquid L rises.

[0035] 7. Action and Effects According to the hydrogen generator 1 of the first embodiment, metal pieces M containing aluminum or an aluminum alloy are stored in a metal piece storage section 20 provided in the reaction vessel 10, divided into a plurality of storage areas 21 (21a to 21f). The amount and concentration of the reaction liquid L, which is a strong alkaline aqueous solution, supplied to the reaction vessel 10 is set according to the amount of the metal pieces M, and the reaction liquid L is supplied to the reaction vessel 10 so that the metal pieces M react with the reaction liquid L sequentially for each storage area 21 (21a to 21f). Therefore, compared to when the reaction liquid L is supplied to the entire metal pieces M, the amount of metal pieces M contributing to a single reaction can be reduced, thereby suppressing the sudden generation of reaction heat. Therefore, a cooling device or a stirring device to suppress thermal runaway is not required, and equipment costs can be reduced.

[0036] Furthermore, in the hydrogen generator 1 of this embodiment 1, the reaction between the metal pieces M and the reaction solution L can proceed in a strong alkaline environment, so the entire amount of aluminum can be used for hydrogen generation, improving the hydrogen generation efficiency. Furthermore, the improved hydrogen generation efficiency allows the amount of hydrogen generated to be secured even when a relatively small reaction vessel 10 is used, so using a small reaction vessel 10 can reduce the maintenance costs of the reaction vessel 10.

[0037] Furthermore, in the first embodiment, in the metal piece storage unit 20, the multiple storage areas 21a-21f are arranged in the vertical direction Y within the reaction tank 10. The control unit 40 is configured to control the supply of the reaction liquid L to sequentially raise the water levels LH1, LH2 of the reaction liquid L within the reaction tank 10, so that the metal pieces M in the storage areas 21a-21f located vertically downward among the multiple storage areas 21a-21f react with the reaction liquid L in sequence. This allows the amount of metal pieces M contributing to a single reaction to be reduced with a simple configuration, thereby suppressing the sudden generation of reaction heat and easily reducing equipment costs.

[0038] Furthermore, in this embodiment 1, the metal piece storage section 20 has separation regions 23a-23f that separate the adjacent storage regions 21a-21f from each other. This prevents the scattered reaction liquid L from reaching the metal pieces M in the upper tray members 21b-21f, even if part of the reaction liquid L is scattered upward due to the reaction in the lower tray member 21a, thereby further preventing thermal runaway.

[0039] Furthermore, in the first embodiment, the control unit 40 can set the water level LH1 of the reaction liquid L to a state where it reaches the first storage region 21a included in the plurality of storage regions 21, thereby creating a first state in which the metal pieces M in the first storage region 21a have reacted with the reaction liquid L, while the metal pieces M in the second storage region 21b located vertically above the first storage region 21a have not reacted with the reaction liquid L. Then, after the first state, the control unit 40 can set the water level LH2 of the reaction liquid L to a state where it reaches the second storage region 21b located vertically above the first storage region 21a, thereby creating a second state in which the metal pieces M in the first storage region 21a and the metal pieces M in the second storage region 21b have reacted with the reaction liquid L. This makes it possible to adjust the amount of metal pieces M involved in the reaction simply by controlling the water level of the reaction liquid L, i.e., the supply amount, and therefore thermal runaway can be easily suppressed.

[0040] In addition, in the present embodiment 1, the control unit 40 controls the supply of the reaction liquid so that the first state is maintained for a predetermined period of time, and then the first state transitions to the second state, thereby further preventing the metal pieces M involved in the reaction from becoming excessive, and thus more easily preventing thermal runaway.

[0041] In the first embodiment and the first to third modifications, the storage area 21 (21a to 21f) can be formed by combining one or more of a dish-shaped member, a mesh-shaped member, a cylindrical member, and a spiral staircase-shaped member on which the metal piece M can be placed. This allows the storage area 21 to have various shapes, thereby achieving the above-mentioned effects.

[0042] Furthermore, in the present embodiment 1, the amount of metal pieces M stored in each of the storage areas 21a to 21f is evenly distributed, which eliminates the need to change the amount of metal pieces M for each of the storage areas 21a to 21f, thereby improving workability.

[0043] In addition, in this embodiment 1, the amount of metal pieces stored in the storage area may be greater the lower the vertical position. In this case, since there is little heat generated in the early stages of the reaction, by increasing the amount of metal pieces M involved in the reaction, the overall time until the reaction is completed can be shortened.

[0044] Furthermore, in this embodiment 1, the reaction liquid L is an aqueous NaOH solution, and the control unit 40 controls the amount and concentration of the reaction liquid L supplied to the reaction tank 10 so that the molar ratio between the total amount of aluminum contained in the metal pieces M stored in the metal piece storage unit 20 and the total amount of NaOH aqueous solution supplied to the reaction tank 10 is 1:1 or more. This allows the total amount of aluminum contained in the metal pieces M stored in the metal piece storage unit 20 to be used for hydrogen generation, further improving the efficiency of hydrogen generation.

[0045] Furthermore, in the first embodiment, the reaction vessel 10 is configured to be able to be sealed with the metal piece storage section 20 housed therein, and the reaction liquid supply section 30 is configured to be able to supply the reaction liquid L into the sealed reaction vessel 10. The reaction vessel 10 further includes a gas substitution section 50 that substitutes the gas phase in the sealed reaction vessel 10 with a gas that is inert to hydrogen. This makes it possible to suppress unintended hydrogen reactions and obtain highly pure hydrogen.

[0046] As described above, according to the above embodiment, it is possible to provide the hydrogen generation device 1 that can improve the efficiency of hydrogen generation at low cost. [Explanation of symbols]

[0047] 1 Hydrogen generator 10 Reaction vessel 20 Metal piece storage section 21, 21a-21f Storage area 23, 23a~23f separated area 30 Reaction liquid supply unit 40 Control Unit 50 Gas replacement section 60 Hydrogen recovery section 70 By-product Recovery Section

Claims

1. A hydrogen generation device that generates hydrogen by reacting a plurality of metal pieces including aluminum or an aluminum alloy with a reaction solution consisting of a strong alkaline aqueous solution, A reaction vessel; a metal piece storage unit provided in the reaction tank and having a plurality of storage areas for storing the plurality of metal pieces in a separated manner; a reaction liquid supply unit that supplies the reaction liquid to the reaction tank while the metal piece storage unit is installed in the reaction tank; a control unit that controls the amount and concentration of the reaction solution supplied to the reaction tank according to the amount of the metal pieces stored in the metal piece storage unit, and controls the supply of the reaction solution so that the metal pieces react with the reaction solution in each storage area in sequence; A hydrogen generating device comprising:

2. In the metal piece storage unit, the plurality of storage areas are arranged in a vertical direction within the reaction tank, 2. The hydrogen generation device according to claim 1, wherein the control unit is configured to control the supply of the reaction liquid to sequentially raise the water level of the reaction liquid in the reaction tank, and to react with the reaction liquid sequentially from the metal piece in the storage region located vertically downward among the plurality of storage regions.

3. The hydrogen generation device according to claim 1 or 2, wherein the metal piece storage section has a separation region that separates the adjacent storage regions from each other.

4. the control unit causes the water level of the reaction liquid to reach a first storage area included in the plurality of storage areas, thereby creating a first state in which the metal piece in the first storage area has reacted with the reaction liquid, and the metal piece in a second storage area located vertically above the first storage area has not reacted with the reaction liquid; 3. The hydrogen generation device according to claim 2, wherein, after the first state, the water level of the reaction liquid is set to a state in which it reaches a second storage area included in the plurality of storage areas located vertically above the first storage area, thereby creating a second state in which the metal pieces in the first storage area and the metal pieces in the second storage area are reacting with the reaction liquid.

5. The hydrogen generation device according to claim 4 , wherein the control unit controls the supply of the reaction liquid so that the first state transitions to the second state after the first state has been maintained for a predetermined period of time.

6. 3. The hydrogen generation apparatus according to claim 2, wherein the storage area is formed by combining one or more of a dish-shaped member, a mesh-shaped member, a cylindrical member, and a spiral staircase-shaped member on which the metal piece can be placed.

7. 3. The hydrogen generation device according to claim 1, wherein the amount of the metal pieces stored in each of the plurality of storage regions is evenly distributed.

8. 3. The hydrogen generation device according to claim 1, wherein the amount of the metal pieces stored in the storage area increases as the metal pieces are located lower in the vertical direction.

9. the reaction liquid is an aqueous NaOH solution, 3. The hydrogen generation device according to claim 1, wherein the control unit controls the amount and concentration of the reaction solution supplied to the reaction tank so that the molar ratio of the total amount of aluminum contained in the metal pieces stored in the metal piece storage unit to the total amount of the NaOH aqueous solution supplied to the reaction tank is 1:1 or more.

10. The reaction tank is configured to be sealable with the metal piece storage section housed therein, the reaction solution supply unit is configured to be able to supply the reaction solution into the sealed reaction tank, 3. The hydrogen generation device according to claim 1, further comprising a gas replacement unit that replaces the gas phase in the sealed reaction vessel with a gas that is inert to hydrogen.

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