WO2008001489A1 - Hydrogen generator and hydrogen generation process - Google Patents

Abstract

Disclosed is a hydrogen generator which enables to generate much hydrogen-containing gas at lower cost. Also disclosed is a process for generating hydrogen. Specifically disclosed is a hydrogen generator comprising a container section for holding an acidic aqueous solution containing a deuterium component, a space section for forming an atmosphere containing the acidic aqueous solution, and an electric discharge device for generating a hydrogen-containing gas by causing an electric discharge in the space section. In particular, D2SO4 is used as the deuterium component, and an arc discharge is utilized as the electric discharge.

Description

 Specification

 Hydrogen generator and hydrogen generation method

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for generating a gas containing hydrogen.

 In recent years, in view of environmental problems and energy problems, research and development of fuel cells and systems using the same have been actively conducted, and demand for hydrogen, which is the most common fuel for these fuel cells, has been increasing. Is also growing.

 [0003] As a method for obtaining such hydrogen, various technologies such as a method for reforming methanol, natural gas or city gas have been proposed and actually practiced. Since raw materials such as gas and city gas are limited, new energy problems may occur in the future.

[0004] On the other hand, attention is focused on water as a substance that exists on the earth as compared with methanol, natural gas, or city gas, and contains hydrogen atoms, and hydrogen is generated using this water as a raw material. Various techniques have been proposed.

 [0005] For example, in Patent Document 1, a hydrogen generation apparatus including a hydrogen generation tank configured to store an acidic aqueous solution and to be able to immerse a metal having a higher ionization tendency than hydrogen in the acidic aqueous solution. Proposed.

 [0006] Further, in Patent Document 2, hydrogen gas production in which hydrogen gas is generated by bringing a single metal into contact with a deuterium acidic aqueous solution in which at least some of the hydrogen atoms in the acidic aqueous solution are substituted with deuterium atoms. A method has been proposed.

[0007] However, in the techniques proposed in Patent Document 1 and Patent Document 2, metal is necessary as a consumable to be immersed in the acidic aqueous solution, and thus the cost is high, and the amount of hydrogen generation is not necessarily large. There is a problem that it cannot be done. [0008] In contrast, one of the inventors of the present application, for example, in Non-Patent Document 1, discloses a technique for generating a gas containing hydrogen by causing plasma electrolysis in an atmosphere containing droplets containing deuterium. is suggesting.

 Patent Document 1: Japanese Unexamined Patent Publication No. 2003-20202

 Patent Document 2: International Publication No. 02Z066368

 Non-Patent Document 1: Tadahiko Mizuno et al., “Hydrogen Evolution by Plasma Electrolysis in Aqueous Solution”, Journal of Japan Society of Applied Physics, 44 (1 A), 2005

 Disclosure of the invention

 Problems to be solved by the invention

However, the plasma generator used in the technique proposed in Non-Patent Document 1 has a complicated structure and is expensive, and there is still room for improvement from the viewpoint of obtaining a hydrogen-containing gas at a low cost. Hot.

In view of the above-described conventional problems, an object of the present invention is to provide a hydrogen generation method capable of generating a large amount of hydrogen-containing gas at a lower cost.

. Another object of the present invention is to provide a hydrogen generation apparatus that can be suitably used for such a hydrogen generation method.

 Means for solving the problem

In order to solve the above problems, the present invention provides:

 A holding unit for holding an acidic aqueous solution containing deuterium;

 A space in which an atmosphere containing the acidic aqueous solution is formed;

 A discharge device for generating a hydrogen-containing gas by causing discharge in the space;

 A hydrogen generator is provided.

[0012] According to such a configuration, an acidic aqueous solution containing deuterium can be more easily and efficiently decomposed with low energy by using inexpensive deuterium and water as raw materials and an apparatus having a simple configuration. Can produce a large amount of hydrogen (hydrogen-containing gas) at low cost. [0013] The present invention also provides a hydrogen generation method that can be suitably performed using the hydrogen generation apparatus. That is, the present invention

 Forming an atmosphere containing an acidic aqueous solution containing deuterium (1), generating a hydrogen-containing gas by causing a discharge in the atmosphere (2),

 A method for producing hydrogen is also provided.

[0014] According to such a configuration, an acidic aqueous solution containing deuterium can be more easily and efficiently decomposed with low energy by using inexpensive deuterium and water as raw materials and a device having a simple configuration. Can produce a large amount of hydrogen (hydrogen-containing gas) at low cost.

[0015] The hydrogen generator further includes a heating device, a spraying device, or an ultrasonic generator, and the atomized acidic solution in the space portion by the heating device, the spraying device, or the ultrasonic generator. It is preferable to form an atmosphere containing an aqueous solution. In particular, in the step (1), it is preferable to form a mist atmosphere containing the acidic aqueous solution.

[0016] According to such a configuration, the acidic aqueous solution can be more reliably present in a place where discharge occurs (for example, a discharge path), and hydrogen can be generated more efficiently.

 [0017] In the hydrogen generator, the discharge device is preferably an arc discharge generator that causes arc discharge. That is, in the above step (2)

It is preferable to cause arc discharge in the atmosphere.

[0018] According to such a configuration, the voltage required to start the arc discharge is relatively high, but since the sustain voltage is low, hydrogen can be generated at a lower cost.

[0019] The acidic aqueous solution used in the hydrogen generator and the hydrogen generation method preferably contains D ₂ 0, and preferably contains D ₂ S 0 ₄ .

[0020] Thus, the present inventors have found that hydrogen can be generated more efficiently when the acidic aqueous solution contains a deuterium component. The reason is not clear However, we believe that excess energy is generated by the transmutation reaction near the tip of the electrode where arc discharge occurs, and a large amount of hydrogen can be generated.

 [0021] The pH of the acidic aqueous solution is preferably 2.0 to 3.5.

 In this pH range, hydrogen can be generated more efficiently. The invention's effect

 [0022] According to the present invention, it is possible to provide a hydrogen generation method capable of generating a large amount of hydrogen-containing gas at a lower cost, and a hydrogen generation apparatus that can be suitably used for such a hydrogen generation method. Can be provided.

 Brief Description of Drawings

 [0023] FIG. 1 is a schematic cross-sectional view showing an embodiment of a hydrogen generator of the present invention.

 FIG. 2 is a schematic cross-sectional view of the hydrogen generator of the present invention used in the examples. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto. FIG. 1 is a schematic sectional view showing a preferred embodiment of the hydrogen generator of the present invention. First, the configuration of the hydrogen generator 1 of the present invention shown in FIG. 1 will be described.

 A hydrogen generator 1 shown in FIG. 1 includes a holding unit 4 that holds an acidic aqueous solution 2 containing deuterium, a space 6 that forms an atmosphere containing an acidic aqueous solution, and an upper part 8 of the space 6. A discharge device (including a positive electrode 8a and a negative electrode 8b) for causing a discharge to generate a hydrogen-containing gas. Further, the hydrogen generator 1 of the present embodiment includes an atmosphere forming device 10 including a cellular container for forming an atmosphere including the acidic aqueous solution 2. However, although not shown in the drawing, the cellular container can be opened at least partially with respect to the holding part 4 and contains an acidic aqueous solution.

[0026] As the acidic aqueous solution 2 containing deuterium, various acidic aqueous solutions containing deuterium as one component can be used. Acid components contained in the acidic aqueous solution 2 include, for example, inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid, as well as citrate, glycine, gay cinnamate, succinate, salicylic acid, formic acid, glutamic acid, and And organic acids such as rubic acid, oxalic acid, tartaric acid, lactic acid and acetic acid. Two or more of these acid components may be contained in the acidic aqueous solution 2, or an inorganic acid and an organic acid may be contained in combination.

[0027] Among them, deuterium (D ₂ 0) in which some hydrogen atoms are replaced with deuterium atoms, bisulfuric acid (D ₂ S0 ₄ ) in which some hydrogen atoms are substituted with deuterium atoms, or It is preferable that an acid component such as dutrium tellurium (D ₂ S) is contained in the acidic aqueous solution 2 as a deuterium component.

[0028] In particular, an acidic aqueous solution 2 preferably contains at least one heavy hydrogen component of D ₂ 0 and D ₂ S0 ₄ 0. 5~ 1 0 vol%. In such a range, the present inventors have found through experiments that more hydrogen can be generated when a discharge occurs in a mist atmosphere of the acidic aqueous solution 2. That is, if it is 0.5 volume% or more, hydrogen can be generated more reliably, and if it is 10 volume% or less, it is preferable from the viewpoint of cost reduction.

Furthermore, the acidic aqueous solution 2 preferably contains 0.5 to 5.0% by volume of at least one deuterium component of D ₂ 0 and D ₂ S0 ₄ . Within this range, hydrogen can be generated more reliably and at low cost.

Among these, it is preferable that the deuterium component is D ₂ S0 ₄ . As described above, the acidic aqueous solution contains a deuterium component, so that excess energy is generated by the transmutation reaction near the tip of the electrode where arc discharge occurs, and a large amount of hydrogen can be generated. More specifically, S in D ₂ S0 ₄ acts as a catalyst on the surface of the anode 8 a, the surface of the anode 8 a acts as a reactant, a transmutation reaction occurs, and a large amount of hydrogen gas is generated. It is considered a thing.

 Here, as the anode 8 a and the cathode 8 b, conductive materials such as various metals can be used. For example, carbon (C), tungsten (W), platinum (P t) and palladium (Pd ) Etc. Of these, platinum is preferably used from the viewpoint of high reactivity.

[0032] The acidic aqueous solution 2 may be acidic (about pH 7 or less), but the pH is preferably about 2.0 to about 3.5, for example. In such a range, Hydrogen can be generated more reliably when a discharge occurs in a foggy atmosphere of the acidic aqueous solution 2.

 As the holding part 2 for holding the acidic aqueous solution 4, various containers can be used as long as they are made of a material having chemical resistance that is not deteriorated by the acidic aqueous solution 2. For example, a thermoplastic resin such as a fluororesin such as polytetrafluoroethylene (PTFE), an inorganic material such as glass, or a metal material such as aluminum, titanium, or an alloy thereof.

 [0034] Note that the holding part 2 in FIG. 1 has a bottomed cylindrical shape, has a concave vertical section, and has an opening above, but is sealed with the above-described fluororesin cap 2a. . Here again, the material constituting the cap 2 a preferably has chemical resistance that does not deteriorate due to the acidic aqueous solution 2.

 [0035] An atmosphere forming device 10 made of a cellular container is connected to the space 6 so that an atmosphere containing the acidic aqueous solution 2 is formed in the space 6 (step (1)). Therefore, the atmosphere forming device 10 includes not only the above-described cellular container but also a heating device, a spraying device, an ultrasonic generator, etc., although not shown. What is important is to form an atmosphere containing an acidic aqueous solution in the holding part 4 (particularly an atmosphere containing a mist-like acidic aqueous solution).

 [0036] In the present invention, it is important to form an atmosphere containing the acidic aqueous solution in the holding portion 4 (particularly, an atmosphere containing a mist-like acidic aqueous solution) and cause discharge in the atmosphere. In this case, after forming an atmosphere containing an acidic aqueous solution, a discharge may be generated in the atmosphere. In particular, when a discharge occurs in a mist-like atmosphere, the amount of electric power is small and the reaction efficiency can be increased as compared with the conventional discharge in an aqueous solution.

Therefore, the cellular container may be omitted, and a heating device, a spray device, or an ultrasonic generator may be provided inside or outside the holding unit 4. In FIG. 1, an atmosphere forming device 10 composed of a cellular container is provided in the holding unit 4, but the cellular container is omitted, and the holding unit 4 itself is installed on a magnetic stirrer with a heating device. A jet that sucks and sprays acidic aqueous solution from the holder 4 A fogging device may be connected to the holding unit 4 or an ultrasonic transducer may be connected to the holding unit 4 for connection.

 According to the heating apparatus, the acidic aqueous solution 2 can be gasified (vaporized) by heating, and an atmosphere containing the gasified acidic aqueous solution 2 can be formed in the space 6. Further, according to the spraying device, the acidic aqueous solution 2 can be supplied (sprayed) in the space 6 in the form of a mist. Furthermore, according to the ultrasonic generator, the acidic aqueous solution 2 can be gasified (vaporized) by applying ultrasonic vibration to form an atmosphere containing the gasified acidic aqueous solution 2 in the space 6.

 [0039] Acidic aqueous solution gasified or atomized by the atmosphere forming apparatus 10

 2 moves the space 6 upward along the arrow X. A discharge device including an anode 8 a and a cathode 8 b is provided in the upper portion 8 of the space 6. In the atmosphere containing the acidic aqueous solution 2 in the upper portion 8 of the space 6, deuterium contained in the acidic aqueous solution 2 is decomposed to generate hydrogen by causing discharge (step (2)).

 [0040] Here, as the discharge device, it is preferable to use a discharge device capable of generating arc discharge. Any arc discharge generator may be used as long as it can generate arc discharge between the anode 8a and the cathode 8b, and a conventionally known apparatus can be used.

 [0041] Examples of the discharge include arc discharge, glow discharge, and plasma discharge. The discharge is low in voltage and safe, and a versatile discharge device can be used to efficiently generate hydrogen. From the viewpoint of being able to do so, the present inventors decided to adopt arc discharge.

[0042] The voltage and current density between the electrodes at the time of discharge may be appropriately selected within a range that does not impair the effect of the present invention. it may be set, the current density is, for example, 1 0 0-1 may be set to OOO AZ cm ^2.

[0043] Further, the temperature of the atmosphere can be increased by the heat of reaction without any particular heating. Therefore, a cooling device may be provided, and the ambient temperature remains at room temperature. However, from the viewpoint of improving the reactivity, it is preferable that the temperature of the atmosphere is higher. For example, the temperature is controlled to be 70 ° C to 100 ° C, and 70 ° C to 80 ° C. preferable.

 [0044] Although the reaction can proceed even if the pressure in the atmosphere is not particularly increased, it is preferably controlled to a high pressure from the viewpoint of increasing the reaction efficiency. For example, it can be controlled to 3 0 0 to 5 0 0 at m. Also, the supercritical state may be formed by controlling the temperature and pressure.

 The gas containing hydrogen generated by the above discharge moves along the direction of arrow Y through the pipe 9 connected to the upper portion 8. Here, although not shown, it is preferable to provide a gas flow meter, a mass spectrum analyzer, a hydrogen collector, etc. at the tip of the pipe 9.

 [0046] Further, on the upstream side of the hydrogen collection unit, a condensing unit is provided so as to cover the pipe 9, and the water contained in the gas containing hydrogen is condensed and removed by flowing a cooling fluid such as cooling water. May be. In this way, a highly pure hydrogen-containing gas can be obtained.

 Example

 [0047] 1. Configuration of hydrogen generator

 In this example, a hydrogen generator having the structure shown in FIG. 2 was produced to generate hydrogen. A holding unit 4 made of a bottomed cylindrical container made of polytetrafluoroethylene and having an opening with a diameter of 7 cm was prepared, and the container was placed on a magnetic stirrer equipped with a heating device. Here, the heating device served as the atmosphere forming device 10.

 [0048] Next, the opening of the holding portion 4 was closed with a rubber cap 2a made of Teflon (registered trademark). The cap 2a is provided with a through-hole, and in order to capture the gas generated in the holding part 4, a quartz glass pipe 9 is passed through the through-hole, and the space part 6 of the pipe 9 is relatively in the middle. A large part (upper part) 8 was formed, and a Tandastain anode 8a and a tungsten cathode 8b were installed.

[0049] In order to analyze the gas generated in the upper part 8, the upper end of the pipe 9 Connect a Tygon tube with a diameter of 8 mm (not shown) to the end of the arrow Y, and connect the gas flow meter (model 31 00 made by Coflock Co., Ltd.) and the control unit (model CR made by Coffrock Co., Ltd.) —700) is connected, and a mass spectrum analyzer (Rega_20 made by ULVAC, Inc.) is installed downstream of the gas flowmeter.

1) Connected.

[0050] 2. Hydrogen production

Into the holding unit 4, the acidic aqueous solution 2 containing 0.25 vol% of 0 ₂ 50 ₄ is placed, and the temperature of the heating device located at the bottom of the holding unit 4 is set to 85 ° C to generate steam of the acidic aqueous solution 2 I let you. Then, a voltage of 30000 V is intermittently applied between the anode 8 a and the cathode 8 b, a current of 0.37 to 4.3 mA is passed, and arc discharge is performed in the vapor of the acidic aqueous solution 2. Formed.

 [0051] When an arc discharge occurred, gas was generated from the upper portion 8. When the gas was measured with a gas flow meter and mass spectrum analyzer connected to pipe 9, hydrogen gas was generated 500 to 1 000 times the amount converted from the current value (stoichiometric amount). It was.

 Industrial applicability

 [0052] According to the hydrogen generation device and the hydrogen generation method of the present invention, a large amount of hydrogen can be obtained in a short time at a low cost. For example, a fuel cell, a hydrogen gas driving device, and a hydrogen self-charging turbocharger In addition, it can be suitably used for hydrogen gas supply in a cogeneration system using an electric vehicle using a hydrogen self-sufficient turbocharger.

Claims

The scope of the claims  [1] a holding unit for holding an acidic aqueous solution containing deuterium;  A space in which an atmosphere containing the acidic aqueous solution is formed;  A discharge device for generating a hydrogen-containing gas by causing discharge in the space;  A hydrogen generator characterized by comprising:  [2] comprises a heating device, a spray device or an ultrasonic generator,  2. The hydrogen generation apparatus according to claim 1, wherein an atmosphere containing the acidic aqueous solution in the form of a mist is formed in the space portion by the heating device, the spraying device, or the ultrasonic generator. [3] the discharge device causes arc discharge;  The hydrogen generator according to claim 1, wherein [4] The acidic aqueous solution contains a deuterium component,  The hydrogen generator according to claim 1, wherein [5] The deuterium component is D ₂ SO ₄ ,  The hydrogen generator according to claim 4, wherein: [6] The acidic aqueous solution contains 0.5 to 10% by volume of the deuterium component,  The hydrogen generator according to claim 4, wherein: [7] forming an atmosphere containing an acidic aqueous solution containing deuterium (1);  A step of generating hydrogen-containing gas by causing discharge in the atmosphere ( 2) and  A hydrogen generation method comprising: [8] The hydrogen generation method according to [7], wherein, in the step (1), an atmosphere containing the mist-like acidic aqueous solution is formed. [9] [10] The acidic aqueous solution contains a deuterium component,  The method for producing hydrogen according to claim 7, wherein: [11] The deuterium component is D ₂ S0 ₄ ,  The hydrogen generator according to claim 10.  12. The hydrogen generation method according to claim 10, wherein the acidic aqueous solution contains 0.5 to 10% by volume of the deuterium component.