Hydrogen generation fuel body and hydrogen generator

Abstract

To provide a hydrogen generation fuel body capable of suppressing rapid generation of hydrogen with a simple configuration.SOLUTION: A hydrogen generation fuel body is housed in a hydrogen fuel storage chamber of a hydrogen generator and includes a hydrogen generating agent for generating hydrogen gas by reacting with a reaction solution. The hydrogen generation fuel body includes a hydrogen generating agent layer in which the hydrogen generating agent is layered, and a diffusion member which is alternately laminated with the hydrogen generating agent layer and permeates and diffuses the reaction solution.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a hydrogen-producing fuel element for generating hydrogen, and a hydrogen generating apparatus. [Background technology]

[0002] It is known that hydrogen can be generated by supplying a liquid substance (e.g., water) to a mixture of an inorganic hydride (e.g., sodium borohydride) and a reaction promoter (e.g., boric acid). There is also a device that generates hydrogen gas by reacting a hydrogen generating agent with a reaction liquid (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-21514 A [Patent Document 2] JP 2013-49584 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, when water is added to a mixture of sodium borohydride and boric acid, hydrogen is produced rapidly in the initial stage. In order to prevent such a sudden generation of hydrogen, it is necessary to control the amount of water supplied, which makes the device configuration complicated.

[0005] In consideration of the above, an object of the present disclosure is to provide a hydrogen generation fuel element and a hydrogen generation device that can suppress rapid hydrogen generation with a simple configuration. [Means for solving the problem]

[0006] The hydrogen generation fuel body of the first aspect is a hydrogen generation fuel body that is stored in a hydrogen fuel storage chamber of a hydrogen generation device and includes a hydrogen generating agent that reacts with a reaction liquid to generate hydrogen gas, and includes a hydrogen generating agent layer in which the hydrogen generating agent is layered, and a diffusion member that is stacked alternately with the hydrogen generating agent layers and allows the reaction liquid to penetrate and diffuse.

[0007] The hydrogen generating fuel element according to the first aspect includes a hydrogen generating agent that reacts with a reaction liquid to generate hydrogen gas, and is used by being stored in a hydrogen fuel storage chamber of a hydrogen generating device.

[0008] The hydrogen generating fuel element is configured by alternately laminating hydrogen generating agent layers in which the hydrogen generating agent is arranged in layers and a diffusion member that allows the reaction liquid to penetrate and diffuse into the surface.

[0009] To generate hydrogen, a reaction liquid is supplied from above to a hydrogen fuel storage chamber containing a hydrogen generating fuel element. Note that the reaction liquid is supplied in an amount, for example, at least that required for reaction with all of the hydrogen generating agent.

[0010] When a reaction liquid is supplied to the hydrogen fuel storage chamber, first, the upper diffusion member diffuses and permeates the reaction liquid over the entire surface of the hydrogen generating agent layer below, and the reaction liquid that has permeated downward from the diffusion member reacts with the hydrogen generating agent in the hydrogen generating agent layer to generate hydrogen.

[0011] The diffusion member can diffuse the reaction liquid supplied from above over the entire surface of the hydrogen generating agent layer below it, and can cause the reaction liquid to permeate (in other words, supply) over the entire surface of the hydrogen generating agent layer located below the diffusion member. This allows the reaction liquid to come into contact with the entire hydrogen generating agent in the hydrogen generating agent layer located below the diffusion member, making it possible to reliably react the reaction liquid with the hydrogen generating agent to generate hydrogen.

[0012] The reaction liquid that has permeated the hydrogen generating agent layer then permeates the diffusion member located below it, and the diffusion member causes the reaction liquid that has permeated the upper hydrogen generating agent layer to permeate and diffuse over the entire surface of the hydrogen generating agent layer located below the diffusion member, and the reaction liquid that has permeated downward from the lower diffusion member reacts with the hydrogen generating agent in the hydrogen generating agent layer to generate hydrogen.

[0013] Thereafter, the reaction liquid similarly permeates the stacked diffusion members and hydrogen generating agent layers from top to bottom, generating hydrogen for each hydrogen generating agent layer, and since the reaction liquid does not react with the entire amount of hydrogen generating agent at once, the simple configuration can suppress rapid hydrogen generation.

[0014] In a hydrogen-producing fuel element according to a second aspect, the diffusion member is a sheet made of a large number of fibers.

[0015] By forming the diffusion member as a sheet made of a large number of fibers, the supplied reaction liquid can permeate and diffuse.

[0016] The hydrogen generation device of the third aspect is a hydrogen generation device in which the hydrogen generation fuel body of the first aspect is used, and is equipped with a perforated plate that is arranged above the hydrogen fuel storage chamber and has a plurality of holes formed on the upper surface of the hydrogen generation fuel body for dripping the reaction liquid.

[0017] In the hydrogen generation device according to the third aspect, a perforated plate having a plurality of holes formed therein for dripping a reaction liquid onto the upper surface of the hydrogen generating fuel element is provided above the hydrogen fuel storage chamber.

[0018] Therefore, when the reaction liquid is poured onto the perforated plate, the reaction liquid can be temporarily stored on top of the perforated plate, and the reaction liquid can be gradually dripped over time from the holes in the perforated plate into the hydrogen generation fuel body, thereby suppressing pulsations in the hydrogen flow rate compared to when there is no perforated plate. Effect of the Invention

[0019] As described above, the hydrogen generation fuel element of the present disclosure can suppress rapid hydrogen generation with a simple configuration. Furthermore, the hydrogen generation device of the present disclosure can suppress pulsation of the hydrogen flow rate with a simple configuration. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic configuration diagram showing a hydrogen generation fuel element and a hydrogen generation device according to a first embodiment of the present disclosure. [Diagram 2] FIG. 4 is a schematic configuration diagram showing a hydrogen generating fuel element and a hydrogen generating device according to a second embodiment of the present disclosure. [Diagram 3] FIG. 1 is a schematic diagram showing the schematic configuration of an experimental apparatus for generating hydrogen. [Figure 4] 13 is a graph comparing the amount of hydrogen generated with and without a hydrophilic sheet. [Diagram 5] 1 is a graph comparing the amount of hydrogen generated with and without a perforated plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] [First embodiment] A hydrogen generating fuel element 10 and a hydrogen generating device 12 according to a first embodiment of the present disclosure will be described with reference to FIG. In addition, the drawings used in the following description are all schematic, and the dimensional relationships, ratios, etc. of the elements in the drawings do not necessarily correspond to the real ones. Furthermore, the dimensional relationships, ratios, etc. of the elements among multiple drawings do not necessarily correspond to each other.

[0022] 1, the hydrogen generation device 12 includes, as an example, a bottomed, cylindrical, sealable container 14 having a removable lid 14A, and a cylindrically shaped hydrogen generation fuel body 10 is stored inside the container 14. The container 14 in this embodiment is an example of a hydrogen fuel storage chamber.

[0023] A water supply pipe 16 for supplying water W as an example of a reaction liquid, and an exhaust pipe 18 for exhausting hydrogen gas generated in the container are attached to the lid 14A.

[0024] The hydrogen generating fuel body 10 includes hydrogen generating agent layers 22 in which the hydrogen generating agent is layered, and a hydrophilic sheet 20 which is an example of a diffusion member that is alternately laminated with the hydrogen generating agent layers 22 and allows the penetration and diffusion of water W. More specifically, the hydrogen generating fuel body 10 is configured by vertically laminating circular hydrophilic sheets 20 and circular thin hydrogen generating agent layers 22 that contain a hydrogen generating agent, with each hydrogen generating agent layer 22 being sandwiched between the hydrophilic sheets 20, and the hydrophilic sheet 20 being disposed on the top.

[0025] The hydrophilic sheet 20 has hydrophilic properties and has the property of permeating and diffusing water (liquid), and may be made of paper such as filter paper or tissue paper made of many fibers. The hydrophilic sheet 20 may also be made of nonwoven fabric, woven fabric, or the like other than paper.

[0026] In this embodiment, as an example of the hydrogen generating agent used in the hydrogen generating agent layer 22, a mixture of sodium borohydride (NaBH4) and boric acid (B(OH)3) as a reaction accelerator is used.

[0027] Adding water (H2O) to a mixture of sodium borohydride (NaBH4) and boric acid (B(OH)3) produces hydrogen gas and sodium tetraborate, as shown in the following reaction equation: NaBH4+B(OH)3+0.5H2O=4H2+0.5Na2B4O7

[0028] The resulting sodium tetraborate (Na2B4O7) can be reused.

[0029] There is no particular limit to the total number of the hydrogen generating agent layers 22 and the number of the hydrophilic sheets 20. The thickness of the hydrogen generating agent layer 22 is, for example, about 1 mm, but may be thinner or thicker than 1 mm. Taking into consideration the size of the fuel particles, the hydrogen generating agent layer 22 is preferably in the range of about 1 to 2 mm.

[0030] If the sodium tetraborate (Na2B4O7) obtained by the above reaction is thick, water does not easily permeate into it. Therefore, it is preferable to make the hydrogen generating agent layer 22 relatively thin in advance, for example, to a thickness of about 1 mm, so that water can easily permeate into it.

[0031] In this embodiment, a mixture of sodium borohydride (NaBH4) and boric acid (B(OH)3) as a reaction promoter is used as the hydrogen generating agent, but the present disclosure is not limited to this, and any known hydrogen generating agent other than sodium borohydride (NaBH4) may be used as long as it can generate hydrogen by reacting with a reaction liquid such as water. In addition, the reaction promoter may be used as necessary, or may not be used, but it is basically preferable to use a reaction promoter.

[0032] (Action, effect) To generate hydrogen gas from the hydrogen generating device 12, water is supplied into the container 14 housing the hydrogen generating fuel element 10. The water can be supplied from the water supply pipe 16 to above the hydrogen generating fuel element 10 in the container 14 using, for example, a tube pump (not shown). Note that at least an amount of water required for reaction with all of the hydrogen generating agents is supplied.

[0033] When water is supplied onto the hydrogen generating fuel body 10, the water first penetrates the uppermost hydrophilic sheet 20, then diffuses throughout the entire hydrophilic sheet 20, and can then diffuse and penetrate throughout the entire surface of the hydrogen generating agent layer 22 underneath.

[0034] When the water that has permeated downward from the hydrophilic sheet 20 comes into contact with the hydrogen generating agent in the hydrogen generating agent layer 22, the water reacts with the hydrogen generating agent to generate hydrogen gas. The generated hydrogen gas can be discharged to the outside of the container 14 via the discharge pipe 18.

[0035] In this manner, first, water comes into contact with the entire hydrogen generating agent in the hydrogen generating agent layer 22 located below the uppermost hydrophilic sheet 20 to generate hydrogen, and the hydrogen generating agent becomes sodium tetraborate (Na2B4O7) after reacting with water to generate hydrogen. Therefore, the hydrogen generating agent layer 22 becomes a layer of sodium tetraborate (Na2B4O7) after reacting with water to generate hydrogen.

[0036] The layer of sodium tetraborate (Na2B4O7) obtained after hydrogen generation is a thin layer similar to the hydrogen generating agent layer 22, so that water supplied from above permeates downward and is supplied to the lower hydrophilic sheet 20, i.e., the second hydrophilic sheet 20 counting from the top. Thereafter, the water permeating downward from the second hydrophilic sheet 20 reacts with the hydrogen generating agent in the hydrogen generating agent layer 22 located below the second hydrophilic sheet 20 to generate hydrogen gas.

[0037] Similarly, the water supplied into the container 14 permeates downward through the hydrogen generation fuel body 10, and each time the water permeates the hydrogen generating agent layer 22, the water reacts with the hydrogen generating agent to generate hydrogen gas, and the hydrogen generation fuel body 10 continues to generate hydrogen gas until the water permeates the lowest hydrogen generating agent layer 22.

[0038] In the hydrogen generating device 12 of this embodiment, even if water is supplied into the container 14, the water does not react with the entire amount of the hydrogen generating agent at once, so that the simple configuration can suppress the rapid generation of hydrogen gas when water is added. Therefore, if the hydrogen generating fuel body 10 of this embodiment is used, there is no need to control the supply of water.

[0039] Furthermore, since the amount of water supplied is controlled using a control mechanism or the like without suppressing the rapid generation of hydrogen gas, the hydrogen generation device 12 can be provided at low cost with a simple configuration.

[0040] When hydrogen gas is generated, hydrogen gas bubbles are generated inside the hydrogen generating agent layer 22. However, when the bubbles come into contact with the hydrophilic sheet 20, the bubble membrane breaks and disappears, thereby suppressing the generation of bubbles from the hydrogen generation fuel body 10.

[0041] In this embodiment, water was supplied using a tube pump, but the tube pump can be used as needed. If the required amount of water can be supplied onto the hydrogen generation fuel body 10, the tube pump does not need to be used and water can be supplied manually.

[0042] [Second embodiment] A hydrogen generation device 12 according to a second embodiment of the present disclosure will be described with reference to Fig. 2. Note that the same components as those in the first embodiment are given the same reference numerals, and the description thereof will be omitted.

[0043] As shown in FIG. 2, the hydrogen generation device 12 of this embodiment is provided with a water supply pipe 16, an exhaust pipe 18, and an emergency release valve 24 at the top, and a perforated plate 26 is mounted inside on top of the hydrogen generation fuel body 10.

[0044] The perforated plate 26 is a circular plate with a plurality of holes 28 formed at intervals over the entire surface, and by supplying water onto the perforated plate 26, the water can be dripped onto the hydrogen generation fuel body 10 from each of the holes 28. Note that, as an example, the holes 28 are circular and have a diameter of 5 mm, but the shape and diameter of the holes 28 are not limited to those in this embodiment.

[0045] (Action, effect) In the hydrogen generation device 12 of this embodiment, when water is supplied onto the perforated plate 26, the water drips from each hole onto the hydrogen generation fuel body 10. Therefore, the water is not supplied onto the hydrogen generation fuel body 10 in a short time, but is gradually supplied onto the hydrogen generation fuel body 10 over time.

[0046] In this way, by gradually dripping hydrogen from the holes 28 in the perforated plate 26 onto the hydrogen generation fuel body 10 over time, pulsation in the hydrogen flow rate can be suppressed compared to when the perforated plate 26 is not present (for details, see test example B described below).

[0047] By adjusting the diameter of the holes 28 and the number of the holes 28, the time for which water is supplied to the hydrogen-generating fuel element 10 can be adjusted.

[0048] [Test example] Next, in order to confirm the effect of the hydrogen generation device of the present disclosure, an experimental device for generating hydrogen was fabricated and hydrogen generation was compared.

[0049] As shown in FIG. 3, the experimental equipment 50 is composed of a water container 52 for storing water, a tube pump 54, a generator 56, a reactor 58, a catch filter 60 for cooling the hydrogen gas and removing alkaline substances, a silica gel filter 62 for removing moisture from the hydrogen gas, a flowmeter 64 for measuring the flow rate of the hydrogen gas, a data logger 66 for recording the flow rate of the hydrogen gas, a valve 68, a valve 70, a valve 72, a branch 74, and piping connecting these components.

[0050] The reactor 58 is configured to contain the hydrogen-generating fuel element described in the embodiment, or a comparative hydrogen generating agent (a mixture of sodium borohydride (NaBH4) and boric acid (B(OH)3) only).

[0051] When water is supplied to the reactor 58 and hydrogen gas is generated in the reactor 58, the hydrogen gas passes through a catch filter 60, a silica gel filter 62, and a flow meter 64, and the flow rate is measured by the flow meter 64. By measuring the flow rate of the hydrogen gas with the flow meter 64, the amount of hydrogen gas generated can be obtained.

[0052] (Test Example A) In Test Example A, the hydrogen generating fuel element described in the above embodiment or a mixture of sodium borohydride (NaBH4) and boric acid (B(OH)3) was placed in the reactor 58, and water was supplied to the reactor 58 at 40 ml / min for 90 seconds using a tube pump. In other words, 60 ml of water was supplied to the reactor 58 in 90 seconds. The reactor 58 used had a diameter (inner diameter) of 120 mm and a height of 140 mm. The amount of sodium borohydride (NaBH4) in the hydrogen generation fuel body in the reactor was 10 g, and the amount of boric acid (B(OH)3) was 16.3 g. The diameter of the hydrogen generation fuel body was 120 mm, the number of hydrophilic sheets (tissue paper) in the hydrogen generation fuel body was four, and the number of hydrogen generating agent layers was three.

[0053] The graph in Fig. 4 shows the relationship between the flow rate of hydrogen gas and time when hydrogen gas is generated by putting the hydrogen generation fuel element described in the above embodiment into the reactor 58, and when hydrogen gas is generated by putting only a mixture of sodium borohydride (NaBH4) and boric acid (B(OH)3) into the reactor 58. In this graph, the solid line shows the result of hydrogen generation using the hydrogen generation fuel element described in the embodiment (with hydrophilic sheet), and the dotted line shows the result of hydrogen generation using only a mixture of sodium borohydride (NaBH4) and boric acid (B(OH)3) (without hydrophilic sheet).

[0054] As shown in the graph of FIG. 4, when hydrogen gas is generated using the hydrogen generation fuel element described in the embodiment (see the solid graph line), it can be seen that the sudden hydrogen generation (peak) in the initial stage of water supply is suppressed compared to when hydrogen is generated using only a mixture of sodium borohydride (NaBH4) and boric acid (B(OH)3) (see the dotted graph line).

[0055] The table in Figure 4 shows the relationship between the time elapsed during water supply and the amount of hydrogen gas generated. The "%" values ​​in the table are values ​​when the amount of hydrogen gas (23.6 L) generated by the reaction of the entire mixture of sodium borohydride (NaBH4) and boric acid (B(OH)3) with water is taken as 100%.

[0056] (Test Example B) In test example B, a hydrogen generating fuel element having a perforated plate as described in the above embodiment, or only a hydrogen generating fuel element (without a perforated plate) was placed in a reactor 58, and water was supplied using a tube pump.

[0057] The graph in Fig. 5 shows the relationship between the flow rate of hydrogen gas and time when hydrogen gas is generated by placing a hydrogen generation fuel element with a perforated plate described in the above embodiment in the reactor 58 and when hydrogen gas is generated by placing only a hydrogen generation fuel element in the reactor 58. In this graph, the solid line shows the result of hydrogen generation using a hydrogen generation fuel element with a perforated plate described in the above embodiment, and the dotted line shows the result of hydrogen generation using only a hydrogen generation fuel element. The perforated plate used was 120 mm in diameter and had 26 holes with a diameter of 5 mm.

[0058] As shown in the graph in Figure 5, when hydrogen gas is generated using a hydrogen generation fuel element equipped with a perforated plate (see solid graph line), it can be seen that the pulsation of the hydrogen gas flow rate is suppressed after about 15 seconds compared to when hydrogen is generated using only the hydrogen generation fuel element (see dotted graph line).

[0059] [Other embodiments] While one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above, and it goes without saying that the present disclosure can be implemented in various modified forms without departing from the spirit and scope of the present disclosure.

[0060] The flow rate of hydrogen gas can be adjusted by the degree of water penetration in the hydrophilic sheet 20 (which can be adjusted by the fiber thickness and density), the degree of diffusion (which can be adjusted by the fiber thickness and density), the diameter of the hydrogen generation fuel body 10, and the length of the hydrogen generation fuel body 10 (the number of layers between the hydrophilic sheet 20 and the hydrogen generating agent layer 22, the thickness of the hydrophilic sheet 20, the thickness of the hydrogen generating agent layer 22, etc.).

[0061] The hydrophilic sheet 20 may be a porous body such as a sponge, so long as it has hydrophilicity and the property of allowing water (liquid) to permeate and diffuse therethrough. [Explanation of symbols]

[0062] 10 Hydrogen generating fuel body 12 Hydrogen generator 14 Container (hydrogen fuel storage chamber) 20 Hydrophilic sheet (diffusion material) 22 Hydrogen generating agent layer (hydrogen generating agent) 26 Hole Plate 28 holes

Claims

1. A hydrogen generating fuel body that is stored in a hydrogen fuel storage chamber of a hydrogen generating device and has a hydrogen generating agent that reacts with a reaction liquid to generate hydrogen gas, A hydrogen generating fuel body comprising: a hydrogen generating agent layer in which the hydrogen generating agent is layered; and a diffusion member that is laminated alternately with the hydrogen generating agent layers and allows the reaction liquid to penetrate and diffuse.

2. The diffusion member is a sheet made of a large number of fibers. The hydrogen-producing fuel body of claim 1 .

3. A hydrogen generating device using the hydrogen generating fuel assembly according to claim 1 or 2, a hydrogen generating device disposed above the hydrogen fuel storage chamber and equipped with a perforated plate having a plurality of holes formed on the upper surface of the hydrogen generating fuel body for dripping the reaction liquid;

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