Method for producing hydrogen storage material

Abstract

To provide a method for easily producing a hydrogen storage material at a low cost.SOLUTION: A method for producing a hydrogen storage material, comprising allowing coral grains immersed in water stored in a water tank and placed on a mesh plate to adsorb hydrogen by allowing micro-nano bubbles of hydrogen generated by a micro-nano bubble generator immersed in water stored in the water tank and placed under the mesh plate to act on the coral grains.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a hydrogen storage material. [Background technology]

[0002] In living organisms, some of the oxygen taken in through breathing can become more activated than normal. This is called reactive oxygen. In mammals, including humans, it is believed that a few percent of the oxygen taken in is converted into reactive oxygen. Reactive oxygen reacts with various components in the body's metabolic processes, and if there is an excess of it, it is said to be liable to cause cell damage. On the other hand, hydrogen has antioxidant properties and neutralizes the effects of reactive oxygen, so the use of materials that store hydrogen is attracting attention. Furthermore, coral contains all 16 essential minerals, including its main component calcium, as well as magnesium, phosphorus, and potassium, and is used as a health food for the purpose of maintaining good health. In addition, focusing on the benefits of hydrogen and coral, products have been developed in which hydrogen is absorbed into coral. Patent Document 1 describes an invention for a method for producing a fine powder of reduced and fired coral calcium, which is obtained by adding water to raw materials containing coral calcium powder and wheat flour, kneading the mixture, drying the resulting dried molded body, oxidizing and firing it, and then reducing and firing it in a nitrogen and hydrogen gas atmosphere. When coral calcium is ingested or taken into the body as a food additive, it acts as a hydrogen ion-releasing substance. Since hydrogen ions have the effect of adjusting body fluids to a weak alkaline state and suppressing the activity of active oxygen, the fine powder can be used as a health food. Patent Document 2 describes a method for producing a hydrogen storage material obtained by firing powdered coral of a specified particle size at 300 to 550°C for 20 to 60 minutes. It describes that because the coral is fired at a temperature range of 300 to 550°C, the calcium in the coral does not change to calcium oxide, and the calcium in the coral can be effectively used to generate hydrogen. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-245265 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-31299 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the methods for producing hydrogen storage materials disclosed in Patent Documents 1 and 2, there is a risk that the components of the coral may be oxidized or deteriorated during the process of firing the coral. In addition, there are problems such as the high costs of investment in furnaces for firing and the heating energy required.

[0005] An object of the present invention is to provide a method for producing a hydrogen storage material easily and at low cost. [Means for solving the problem]

[0006] (1) To solve the above problems, the present invention provides a method for producing a hydrogen storage material, which comprises applying hydrogen micro-nano bubbles generated by a micro-nano bubble generator immersed in water stored in an aquarium to coral particles immersed in the water stored in the aquarium, thereby causing the coral particles to adsorb hydrogen. (2) Another invention for solving the above problem is the method for producing a hydrogen storage material according to claim 1, wherein the coral grains are placed on a mesh plate placed in the aquarium. (3) Another invention for solving the above problem is the method for producing a hydrogen storage material according to claim 2, wherein the micro-nano bubble generator is placed below the mesh plate immersed in the water. (4) Another invention for solving the above problem is a method for producing a hydrogen storage material according to any one of claims 1 to 3, wherein the micro-nano bubble generator is a static mixer type or a pressurized dissolution type micro-nano bubble generator. (5) Another invention for solving the above problem is a method for producing a hydrogen storage material according to any one of claims 1 to 3, wherein the micro-nano bubble generator is a pore-type micro-nano bubble generator. (6) Another invention for solving the above problem is a method for producing a hydrogen storage material as described in claim 1, characterized in that ultrasonic vibrations are applied to the water stored in the water tank by an ultrasonic vibration device. (7) Another invention for solving the above problem is the method for producing a hydrogen storage material according to claim 1, wherein the micro-nano bubble generator generates a mixed gas of hydrogen and carbon dioxide, thereby adsorbing the hydrogen onto the coral grains. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a method for easily producing a hydrogen storage material at low cost. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a conceptual diagram illustrating a hydrogen storage system to which an embodiment of the present invention is applied. [Figure 2] 1 is a conceptual diagram illustrating a hydrogen storage system to which an embodiment of the present invention is applied. [Figure 3] FIG. 1 is a conceptual diagram illustrating a hydrogen storage system to which another embodiment of the present invention is applied. [Figure 4] (A) is a photograph of coral grains that have absorbed hydrogen, and (B) is a photograph of coral powder that has absorbed hydrogen. [Figure 5] FIG. 2 is a diagram showing the results of measuring the hydrogen content of a hydrogen storage material. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 is a conceptual diagram showing a hydrogen storage system to which the present embodiment is applied. The hydrogen storage system 1 is a system for storing hydrogen in a material such as coral 10. The hydrogen absorption system 1 shown in FIG. 1 is configured by combining a micro-nano bubble generator 20, a pump 22, an ejector 24, a flow meter 26, a hydrogen cylinder 28, a mesh plate 30, a water tank 40, and the like.

[0010] The micro-nano bubble generator 20 is a device that generates micro-nano bubbles 60 in water stored in a water tank 40 using hydrogen supplied from a hydrogen cylinder 28 via an ejector 24. An existing device can be used for the micro-nano bubble generator 20. Distilled water is stored in the water tank 40. The micro-nano bubble generator 20 is placed near the bottom of the water tank 40, immersed in the water stored in the water tank.

[0011] There are several types of micro-nano bubble generator 20, and the present invention is not limited to the micro-nano bubble generation type. For example, a static mixer type can be used as the micro-nano bubble generator 20. A static mixer guides a gas-liquid two-phase flow in a spiral shape using guide vanes. A static mixer can break up the gas-liquid two-phase flow using mushroom-shaped protrusions (current cutters) fixed inside the pipe, generating micro-nano bubble water.

[0012] The micro-nano bubble generator 20 can also be, for example, a pressurized dissolution type. In a pressurized dissolution type micro-nano bubble generator, air is pressurized to about 3 to 4 atmospheres and dissolved in water. When the dissolved air is flushed into the water through a nozzle, the reduced pressure and supersaturated air is released as micro-nano bubbles into the wastewater. The bubble size distribution shows two peaks, one for nanobubbles and one for microbubbles. The liquid containing the generated microbubbles is milky and pure white.

[0013] For example, a micro-pore type can be used as the micro-nano bubble generator 20. The micro-pore type micro-nano bubble generator generates micro-nano bubbles with an average bubble diameter of 720 nm from a membrane with an average pore diameter of 84 nm made by sintering porous glass made from shirasu (whitebait). A surfactant may be added to prevent the bubbles from coalescing.

[0014] The static mixer type and pressure dissolution type described above are types that involve the flow of liquid, while the pore type is a type that does not involve the flow of liquid. The embodiment in Figure 1 shows a micro-nano bubble generator 20 that involves the flow of liquid. A pump 22 sucks up water from a water tank 40, and creates a gas-liquid mixed phase flow with hydrogen supplied from a hydrogen cylinder 28, generating micro-nano bubbles 60.

[0015] The water tank 40 may be large enough to store distilled water and accommodate the micro-nano bubble generator 20, mesh plate 30, etc., but for example, to produce 5 kg to 10 kg of coral, a water tank 40 with a width of approximately 1.5 m, a length of 1 m, and a depth of approximately 80 cm can be used.

[0016] The pump 22 sucks up water in the water tank 40 and pumps it to the ejector 24. The ejector 24 mixes hydrogen supplied from the hydrogen cylinder 28 with water pumped from the pump 22, and sends the mixture to the micro-nano bubble generator 20. The micro-nano bubble generator 20 generates micro-nano bubbles in water in a water tank 40. In the description of this embodiment, microbubbles are bubbles with a diameter of 1 micrometer to several tens of micrometers, and nanobubbles are bubbles with a diameter of 1 micrometer or less. The term micro-nano bubble is used as a general term for both microbubbles and nanobubbles, rather than in the narrow sense of a size intermediate between microbubbles and nanobubbles.

[0017] Nanobubbles are tiny bubbles that are invisible to the naked eye and remain in water for a long time, but when they disappear, they release a large amount of energy. When these hydrogen micro-nano bubbles release energy near the surface of the coral 10, the hydrogen collides with the surface of the coral, causing it to be adsorbed. Therefore, the smaller the bubbles generated, the more energy they release when they disappear, so it is desirable that the bubbles generated be as small as possible. The micro-nano bubble generator 20 is placed below the mesh plate 30 and near the bottom of the aquarium 40.

[0018] Microbubbles are not as fine as nanobubbles, so they appear cloudy in water, and microbubbles rise slowly through the water. The energy released when the bubbles disappear is also large, although not as large as that of nanobubbles. It is desirable to leave the coral 10 grains on the mesh plate 30 underwater in the aquarium 40 for at least 30 minutes after the micro-nano bubble generator 20 starts generating hydrogen micro-nano bubbles 60.

[0019] The coral 10 is placed on a mesh plate 30 that is placed horizontally near the center of the height of the aquarium 40. It is desirable that the coral 10 is crushed to an appropriate degree, but that the grain size is such that the coral 10 does not fall through the mesh of the mesh plate 30. For example, it is desirable that the grain size of the coral 10 is about 2 mm, and it is desirable that the mesh of the mesh plate 30 is fine and coarse, about 2 mm square, so that the coral 10 grains do not fall through.

[0020] The flow meter 26 is a sensor that measures the amount of hydrogen supplied from the hydrogen cylinder 28. The appropriate amount of hydrogen supplied varies depending on the size of the aquarium 40, the amount of water, and the amount of coral 10. The amount of hydrogen supplied can be changed based on the amount of hydrogen supplied measured by the flow meter 26. The amount of hydrogen supplied can be adjusted manually by opening and closing the valve of the hydrogen cylinder 28, or automatically by a solenoid valve.

[0021] The micro-nano bubbles 60 generated by the micro-nano bubble generator 20 do not immediately rise to the surface but diffuse in the water. Nanobubbles do not rise in the water, but microbubbles rise slowly. If the micro-nano bubble generator 20 is placed below the coral 10, the rising microbubbles will come into contact with and stimulate the coral 10, which is expected to have the effect of making the micro-nano bubbles 60 disappear more easily. For this reason, in this embodiment, the coral 10 is placed on top of the mesh plate 30, and the micro-nano bubble generator 20 is placed below the mesh plate 30.

[0022] FIG. 2 is a conceptual diagram illustrating a hydrogen storage system to which this embodiment is applied. The hydrogen storage system 1 in FIG. 2 uses a micropore-type micro-nano bubble generator 70 in combination with the hydrogen storage system in FIG. 1. In other words, in addition to the micro-nano bubble generator 20, a device is also used in which hydrogen supplied directly from a hydrogen cylinder 28 passes through a fine porous membrane to generate micro-nano bubbles that are then released into the water. In this way, a micro-nano bubble generator 70 using a fine porous filter may be used, which does not require the circulation of tank water. In FIG. 2, the micro-nano bubble generator 20 in FIG. 1 is used in combination with the micro-nano bubble generator 70 using a filter membrane, but a system in which only the micro-nano bubble generator 70 using a filter membrane is installed may also be used.

[0023] FIG. 3 is a schematic diagram conceptually illustrating a hydrogen absorption system to which another embodiment is applied. The hydrogen absorption system 2 of FIG. 3 uses an ultrasonic vibration device 80 in combination with the hydrogen absorption system of FIG. 1. The ultrasonic vibration device 80 is placed in contact with the bottom of the water tank 40. Therefore, ultrasonic vibrations are transmitted to the water in the water tank 40 and the micro-nano bubbles 60. The ultrasonic vibrations promote the bursting of the micro-nano bubbles 60, thereby promoting the adsorption of hydrogen to the coral 10. In this way, the ultrasonic vibration device 80 may be installed in addition to the micro-nano bubble generator 20. Furthermore, when using the ultrasonic vibration device 80, it is not necessary to use the micro-nano bubble generator 20; a system in which the ultrasonic vibration device 80 is simply installed in a bubble generator may also be used. Even if the bubbles are not micro-nano bubbles, the ultrasonic vibrations will cause hydrogen to be adsorbed by the coral 10.

[0024] The ultrasonic vibration device may be a known device, for example, an ultrasonic generator having a vibrator that generates ultrasonic waves of 40 kHz.

[0025] Furthermore, in FIG. 3, a carbon dioxide cylinder (not shown) may be prepared in addition to the hydrogen cylinder 28 to generate micro-nano bubbles 60 of a gas mixture of hydrogen and carbon dioxide. Specifically, a hose supplying carbon dioxide from the carbon dioxide cylinder and a hose supplying hydrogen from the hydrogen cylinder 28 may be joined together to mix the hydrogen and carbon dioxide, and the ejector 24 may pump the mixed gas. With this configuration, a mixed gas of hydrogen and carbon dioxide can be generated from the micro-nano bubble generator 20. It has been confirmed that the amount of hydrogen adsorbed by the coral 10 increases by adding carbon dioxide. The molar ratio of carbon dioxide to hydrogen in the mixed gas is preferably 6:4 or 7:3. Instead of generating a mixed gas of hydrogen and carbon dioxide from one micro-nano bubble generator 20, it is also possible to generate micro-nano bubbles 60 of hydrogen and carbon dioxide from two micro-nano bubble generators 20, respectively.

[0026] After hydrogen is adsorbed into the coral 10 particles by the hydrogen storage system 1 or 2 described in Figures 1 to 3, the coral particles with adsorbed hydrogen are dried in a dryer. Then, the coral 10 may be powdered in a grinder. Figure 4(A) is a photograph of coral particles that have absorbed hydrogen, and Figure 4(B) is a photograph of coral powder that has absorbed hydrogen. For example, before being powdered in a grinder, coral 10 is a particle with a particle size of about 2 mm as shown in Figure 4(A), but when this is powdered in a grinder, it becomes coral powder as shown in Figure 4(B). The powdered powder can be sprinkled in water and then easily ingested orally.

[0027] 5 shows the results of measuring the hydrogen content of hydrogen storage materials. Examples 1 to 4 are samples in which 1 kg of coral particles were placed in an aquarium measuring 60 cm wide, 45 cm deep, and 60 cm high and treated with micro-nano bubbles for 20 minutes. Comparative Example 1 is a sample of coral particles that was not treated with micro-nano bubbles and was baked in a vacuum furnace at 400°C for 48 hours. However, the results of Example 1 are the results of quantitative hydrogen analysis of coral particles that were subjected to hot air drying after micro-nano bubble generation treatment in tap water. The results of Example 2 are the results of quantitative hydrogen analysis of coral particles that were subjected to hot air drying after micro-nano bubble generation treatment in mineral-added water. The results of Example 3 are the results of quantitative hydrogen analysis of coral particles that were subjected to natural drying after micro-nano bubble generation treatment in tap water. The results of Example 4 are the results of quantitative hydrogen analysis of coral particles that were subjected to natural drying after micro-nano bubble generation treatment in mineral-added water.

[0028] Quantitative analysis of hydrogen was performed using a Shimadzu gas chromatograph GC-2014AT and a chromatography data processor C-R7A. Each powder sample from Examples 1 to 4 and Comparative Example 1 was weighed out in 3.0 g portions, sealed in a 33 mL vial with 15 mL of water, and allowed to stand at room temperature for a certain period of time. Just before gas sampling, the vial was vigorously shaken to disperse the sample powder that had settled to the bottom. The gas volume in the vial was 18 mL. The elapsed time between sample sealing and sampling was 3 and 6 hours. The quantitative values ​​obtained were the concentrations in the gas phase of the vial. The absolute amount of hydrogen (H concentration × 18 mL) was calculated from the gas volume in the vial, and the concentration of hydrogen generated per 1 g of sample was calculated.

[0029] Comparing Examples 1 to 4, Examples 1 to 3 showed higher hydrogen concentrations after 6 hours than after 3 hours. Example 4 and Comparative Example 1 showed higher hydrogen concentrations after 3 hours than after 6 hours. In Examples 1 to 4, the micro-nano bubbles 60 were treated for 20 minutes and then air-dried or warm-dried, whereas Comparative Example 1 was calcined for 48 hours. Figure 5 does not show experimental results for the same treatment time (20 minutes of micro-nano bubble treatment and 48 hours of vacuum furnace treatment). However, when comparing Examples 1 to 4 with Comparative Example 1, Comparative Example 1 showed higher hydrogen concentrations and generated hydrogen amounts. Although the treatment time is not necessarily proportional to the hydrogen concentration, considering the 20-minute treatment time for Examples 1 to 3 and the 48-hour treatment time for Comparative Example 1, the efficiency of hydrogen absorption by the micro-bubble 60 treatment is considered to be high. Furthermore, calcination consumes thermal energy to maintain the temperature at 400°C for 48 hours, which incurs very high costs. In this regard, micro-nano bubbles are low-cost and highly efficient for producing hydrogen storage materials.

[0030] Furthermore, since it is generally said that a hydrogen concentration exceeding 1 ppm is sufficiently valuable as a product of hydrogen storage material, the measurement results of Examples 1 to 4 in Fig. 5 are sufficiently valuable as a manufacturing method. In other words, if a method that can easily manufacture a hydrogen storage material at low cost by treating micro-nano bubbles 60 for just 20 minutes is used, mass production of hydrogen storage material will also be possible. [Explanation of symbols]

[0031] 1...hydrogen absorption system, 10...coral, 20, 70...micro-nano bubble generator, 22...pump, 24...ejector, 26...flow meter, 28...hydrogen cylinder, 30...mesh plate, 40...aquarium, 60...micro-nano bubbles, 80...ultrasonic vibration device

Claims

1. Coral particles are immersed in water stored in an aquarium. By applying hydrogen micro-nano bubbles generated by a micro-nano bubble generator immersed in the water stored in the water tank, The method is characterized in that hydrogen is adsorbed onto the coral grains. Method for producing hydrogen storage materials.

2. The method for producing a hydrogen storage material according to claim 1 , wherein the coral grains are placed on a mesh plate placed in the water tank.

3. The method for producing a hydrogen storage material according to claim 2 , wherein the micro-nano bubble generator is placed below the mesh plate immersed in the water.

4. The method for producing a hydrogen storage material according to any one of claims 1 to 3, wherein the micro-nano bubble generator is a static mixer type or a pressure dissolution type micro-nano bubble generator.

5. The method for producing a hydrogen storage material according to any one of claims 1 to 3, wherein the micro-nano bubble generator is a pore-type micro-nano bubble generator.

6. 2. The method for producing a hydrogen storage material according to claim 1, wherein ultrasonic vibration is applied to the water stored in the water tank by an ultrasonic vibration device.

7. 2. The method for producing a hydrogen storage material according to claim 1, wherein the micro-nano bubble generator generates a mixed gas of hydrogen and carbon dioxide, thereby causing the hydrogen to be adsorbed onto the coral grains.

Images