CN1906122A - Method for producing hydrogen and hydrogen-producing apparatus used therefor - Google Patents

Method for producing hydrogen and hydrogen-producing apparatus used therefor Download PDF

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Publication number
CN1906122A
CN1906122A CNA2004800410161A CN200480041016A CN1906122A CN 1906122 A CN1906122 A CN 1906122A CN A2004800410161 A CNA2004800410161 A CN A2004800410161A CN 200480041016 A CN200480041016 A CN 200480041016A CN 1906122 A CN1906122 A CN 1906122A
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hydrogen
electrode
fuel
hydrogen production
oxidizing
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CN100526212C (en
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奥山良一
山本好浩
元井昌司
芦田胜二
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GS Yuasa International Ltd
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Yuasa Battery Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Abstract

Disclosed is a method for producing hydrogen wherein a hydrogen-containing gas which includes only a few nitrogen, CO and the like is produced by decomposing a fuel containing an organic matter at low temperatures without supplying an electric energy or while supplying only a few electric energy from the outside. Also disclosed is a hydrogen-producing apparatus used for such a method for producing hydrogen. A hydrogen-producing method and hydrogen-producing apparatus for producing a hydrogen-containing gas by decomposing a fuel containing an organic matter are characterized in that one surface of a separating membrane (11) is provided with a fuel electrode (12) and a fuel containing an organic matter and water is supplied thereto while the other surface of the separating membrane (11) is provided with an oxidizing electrode (14) and an oxidant is supplied thereto, so that the fuel containing the organic matter is decomposed and a hydrogen-containing gas is generated at the fuel electrode (12) side.

Description

Hydrogen production method and hydrogen production apparatus used for the method
Technical Field
The present invention relates to a hydrogen production method for producing a hydrogen-containing gas by decomposing a fuel containing an organic substance at a low temperature, and a hydrogen production apparatus used for the method.
Background
In recent years, countermeasures against environmental problems and resource problems have become important, and one of these countermeasures is the active development of fuel cells. Among fuel cells, Phosphoric Acid Fuel Cells (PAFCs) and Polymer Electrolyte Fuel Cells (PEFCs) use hydrogen as a fuel, and therefore a conversion system for converting hydrocarbons, methanol, and the like, which are raw materials, into hydrogen is required, and development of the conversion system is a particularly important technical problem in the development of fuel cells.
For fuel conversion of PEFC for automobiles, methanol, dimethyl ether (DME), ethanol, natural gas, propane, gasoline, and the like have been studied, and among them, the development of conversion of methanol having the lowest conversion temperature has been most advanced, and at present, three conversion methods, i.e., steam conversion, partial oxidation conversion, and conversion using a combination of these two methods, are used (see non-patent document 1).
Non-patent document 1: "development and practical use of Polymer electrolyte Fuel cell", pp 141-166, 1999, 5/28 d, issued by the Association of technical information
Water vapor is converted by The reaction formula (A) is shown as endothermic reaction, and the conversion temperature is 200-300 ℃.
In the case of using air as the oxidizing gas, partial oxidation is converted from The reaction formula (2) is shown as an exothermic reaction, and the conversion temperature is 200-600 ℃.
In the case of using air as the oxidizing gas, the oxidizing gas is converted (representative example) from The reaction formula (2) shows that the heat release is about one third of partial oxidation, and the conversion temperature is 400-600 ℃.
Further, there is also an invention of a hydrogen generator having high heat efficiency, which is an apparatus for generating hydrogen to be supplied to a hydrogen utilization device such as a fuel cell using a hydrocarbon fuel such as natural gas, LPG, gasoline, naphtha, or kerosene, and water as raw materials (see patent document 1). The device is as follows: "a hydrogen generator having at least a supply unit for a hydrocarbon-based fuel, a combustion unit for the fuel, a water supply unit, a gas mixing unit for mixing the fuel with water or steam to produce a converted gas, and a conversion unit filled with a conversion catalyst, and generating a converted gas containing hydrogen from the converted gas by a catalytic action of the conversion catalyst, wherein at least the gas mixing unit and the conversion unit are directly heated by a combustion exhaust gas generated in the combustion unit via a partition wall". The conversion temperature is as high as about 700 ℃.
Patent document 1: japanese patent No. 3473900 (claim 1, paragraphs [0001], [0017], [0022])
In this way, in any reforming method, reforming at a high temperature of 200 ℃ or higher is necessary for producing hydrogen, and there are problems such as poisoning of the reforming catalyst, removal of CO contained in the reformed gas (hydrogen-containing gas), partial oxidation reforming, or mixing of nitrogen in the air into the gas reformed during the combined reforming.
On the other hand, as a technique for producing a hydrogen-containing gas by decomposing a fuel containing an organic substance at a low temperature, a method and an apparatus for generating hydrogen by an electrochemical reaction are known, and a fuel cell using the hydrogen generated by such an electrochemical method is also known (see patent documents 2 to 5).
Patent document 2: japanese patent application laid-open No. 3328993
Patent document 3: japanese patent application laid-open No. 3360349
Patent document 4: U.S. Pat. No. 6,299,744, U.S. Pat. No. 6,368,492, U.S. Pat. No. 6,432,284, U.S. Pat. No. 6,533,919, and U.S. Pat. No. 2003/0226763
Patent document 5: japanese laid-open patent publication No. 2001-297779
Patent document 2 describes the following invention (claim 1): "a hydrogen generating method, characterized in that a pair of electrodes are provided on two opposing surfaces of a cation exchange membrane, a fuel containing at least methanol and water is brought into contact with an electrode containing a catalyst provided on one surface, electrons are taken out from the electrodes by applying a voltage to the pair of electrodes, a reaction of generating hydrogen ions from the methanol and water is performed on the electrodes, and the generated hydrogen ions are converted into hydrogen molecules by supplying electrons to an electrode provided on the other surface of the one opposing surface of the cation exchange membrane". In addition, it also discloses: water or water vapor is supplied to the fuel electrode together with methanol as fuel, and a voltage is applied to the fuel electrode through an external circuit to extract electrons from the fuel electrode, thereby performing the process at the fuel electrode By passing the hydrogen ions thus generated through a cation-exchange membrane, on the side of the counter electrodeBy passing And hydrogen is selectively produced (paragraph [0033]]～[0038]). Further, patent document 3 describes an invention of a fuel cell using hydrogen generated by such a method (paragraph [0052]]～[0056])。
According to the inventions described in patent documents 2 and 3, hydrogen can be generated at a low temperature (paragraph [0042]of patent document 2 and paragraph [0080]of patent document 3), but a voltage must be applied to generate hydrogen, and hydrogen is generated on the counter electrode side of the fuel electrode (fuel electrode) without supplying an oxidizing agent to the counter electrode, which is significantly different from the hydrogen production method and the hydrogen production apparatus of the present invention.
The invention described in patent document 4 is also different from the inventions described in patent documents 2 and 3 in that protons generated in the anode 112 serving as a fuel electrode permeate the separator 110 and hydrogen is generated in the cathode 114 serving as a counter electrode, but the invention is significantly different from the hydrogen production method and the hydrogen production apparatus of the present invention in that an organic fuel such as methanol is electrically decomposed by applying a voltage from the dc power supply 120 to the anode serving as the fuel electrode and the counter electrode serving as the cathode, and an oxidizing agent is not supplied to the counter electrode on the counter electrode side of the fuel electrode.
Patent document 5 describes that a hydrogen generating electrode (claim 1) for generating hydrogen is provided in the fuel cell system, and that "when a load is maintained between the terminal of the porous electrode 1 and the terminal of the gas diffusion electrode 2 by supplying a liquid fuel containing alcohol and water to the porous electrode (fuel electrode) 1 and supplying air to the gas diffusion electrode (oxidant electrode) 2 on the opposite side, an electrical connection such that a positive potential is applied to the porous electrode 1 from the gas diffusion electrode 2, which is the positive electrode of the MEA2 having a normal fuel cell function, via the load is established. As a result, the alcohol reacts with water to generate carbon dioxide and hydrogen ions, and the generated hydrogen ions pass through the electrolyte layer 5 to generate hydrogen gas at the central gas diffusion electrode 6. On the gas diffusion electrode 6, an electrode reaction occurs at the interface with the other electrolyte layer 7, hydrogen ions are formed again and move in the electrolyte layer 7, and reach the gas diffusion electrode 2. The system is similar to the above-mentioned patent documents 2 to 4 in that hydrogen is generated at a hydrogen generation electrode (gas diffusion electrode 6) by reacting oxygen in the air with the gas diffusion electrode 2 to generate water "(paragraph 0007), and hydrogen is supplied to the fuel cell by generating hydrogen at the hydrogen generation electrode, and hydrogen is generated at the counter electrode side of the fuel electrode.
Further, there are disclosed inventions of a method of oxidizing an alcohol (methanol) with or without applying a voltage or deriving electric energy using a reaction apparatus having a separator in which an anode (electrode a) and a cathode (electrode B) are formed with a proton conductive membrane (ion conductor) interposed therebetween (see patent documents 6 and 7), but both of them relate to a process of oxidizing an alcohol using an electrochemical cell (a product is carbonic acid diester, formalin, methyl formate, dimethoxymethane, or the like), and are not a process of generating hydrogen as a reduced product from only an alcohol.
Patent document 6: japanese patent laid-open No. 6-73582 (claims 1 to 3, paragraph [0050])
Patent document 7: japanese patent laid-open No. 6-73583 ( claims 1 and 8, paragraph [0006])
Disclosure of Invention
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a hydrogen production method for producing a hydrogen-containing gas containing little contamination such as nitrogen and CO by decomposing a fuel containing an organic substance at a low temperature without supplying electric energy from the outside or with supplying only a small amount of electric energy, and a hydrogen production apparatus used in the hydrogen production method.
In order to solve the above problems, the present invention adopts the following method.
(1) A hydrogen production method for producing a hydrogen-containing gas by decomposing a fuel containing an organic substance, characterized in that a fuel electrode is provided on one surface of a separator, the fuel electrode is supplied with a fuel containing the organic substance and water, an oxidizing electrode is provided on the other surface of the separator, an oxidizing agent is supplied to the oxidizing electrode, the fuel containing the organic substance is decomposed, and the hydrogen-containing gas is generated from the fuel electrode side.
(2) The method for producing hydrogen according to (1), wherein the hydrogen-containing gas is produced under open circuit conditions without drawing electric energy from a hydrogen production cell constituting the hydrogen production apparatus to the outside or supplying electric energy to the hydrogen production cell from the outside.
(3) The method for producing hydrogen according to (1), wherein the fuel electrode is anegative electrode, the oxidizing electrode is a positive electrode, and the fuel containing organic matter is decomposed while electric energy is externally discharged, thereby generating a hydrogen-containing gas from the fuel electrode side.
(4) The method for producing hydrogen according to (1), wherein the fuel containing organic matter is decomposed while applying electric energy from outside with the fuel electrode as a cathode and the oxidizing electrode as an anode, and the hydrogen-containing gas is generated from the fuel electrode side.
(5) The method for producing hydrogen according to any one of (1) to (4), wherein the organic substance is an alcohol.
(6) The method for producing hydrogen according to (5), wherein the alcohol is methanol.
(7) The hydrogen production method according to any one of (1) to (4), wherein the oxidizing agent is an oxygen-containing gas or an oxygen gas.
(8) The method for producing hydrogen according to (5), wherein the oxidizing agent is an oxygen-containing gas or oxygen gas.
(9) The method for producing hydrogen according to any one of (1) to (4), wherein the oxidizing agent is a liquid containing hydrogen peroxide.
(10) The method for producing hydrogen according to (5), wherein the oxidizing agent is a liquid containing hydrogen peroxide.
(11) A hydrogen production apparatus for producing a hydrogen-containing gas by decomposing a fuel containing an organic substance, the hydrogen production apparatus comprising a membrane, a fuel electrode provided on one surface of the membrane, a means for supplying the fuel containing the organic substance and water to the fuel electrode, an oxidizing electrode provided on the other surface of the membrane, a means for supplying an oxidizing agent to the oxidizing electrode, and a means for generating the hydrogen-containing gas from the fuel electrode side and extracting the hydrogen-containing gas.
(12) The hydrogen production apparatus according to (11) is characterized by being in an open state without a device for externally leading out electric energy from a hydrogen production cell constituting the hydrogen production apparatus and a device for externally supplying electric energy to the hydrogen production cell.
(13) The hydrogen production apparatus according to (11) is characterized by comprising a device for taking out electric energy to the outside by using the fuel electrode as a negative electrode and the oxidizing electrode as a positive electrode.
(14) The hydrogen generator according to (11) is characterized by comprising a device for applying electric energy from the outside by using the fuel electrode as a cathode and the oxidizing electrode as an anode.
(15) The hydrogen production apparatus according to (11), wherein a voltage between the fuel electrode and the oxidizing electrode is 200 to 1000 mV.
(16) The hydrogen production apparatus according to (12), wherein the voltage between the fuel electrode and the oxidizing electrode is 300 to 800 mV.
(17) The hydrogen production apparatus according to (13), wherein the voltage between the fuel electrode and the oxidizing electrode is 200 to 600 mV.
(18) The hydrogen generator according to (13) above, wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount of the hydrogen-containing gas generated is adjusted by adjusting the derived electric energy.
(19) The hydrogen production apparatus according to (14), wherein a voltage between the fuel electrode and the oxidizingelectrode is 300 to 1000 mV.
(20) The hydrogen production apparatus according to (14), wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount of the hydrogen-containing gas generated is adjusted by adjusting the applied electric energy.
(21) The hydrogen production apparatus according to any one of (11) to (20), wherein the amount of the hydrogen-containing gas to be generated is adjusted by adjusting a voltage between the fuel electrode and the oxidizing electrode.
(22) The hydrogen production apparatus according to any one of (11) to (20), wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount of the hydrogen-containing gas generated is adjusted by adjusting the amount of the oxidizing agent supplied.
(23) The hydrogen production apparatus according to any one of (11) to (20), wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount of the hydrogen-containing gas generated is adjusted by adjusting the concentration of the oxidizing agent.
(24) The hydrogen generator according to (22), wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount of the hydrogen-containing gas generated is adjusted by adjusting the concentration of the oxidizing agent.
(25) The hydrogen production apparatus according to any one of (11) to (20), wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount of the hydrogen-containing gas generated is adjusted by adjusting the amount of the fuel containing the organic matter and water supplied.
(26) The hydrogen production apparatus according to (22), wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount ofthe hydrogen-containing gas to be generated is adjusted by adjusting the amount of the fuel containing the organic matter and water to be supplied.
(27) The hydrogen production apparatus according to (23), wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount of the hydrogen-containing gas to be generated is adjusted by adjusting the amount of the fuel containing the organic matter and water to be supplied.
(28) The hydrogen production apparatus according to any one of (11) to (20), wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount of the hydrogen-containing gas generated is adjusted by adjusting the concentration of the fuel containing an organic substance and water.
(29) The hydrogen production apparatus according to (22), wherein a voltage between the fuel electrode and the oxidizing electrode and/or a production amount of the hydrogen-containing gas are adjusted by adjusting a concentration of the fuel containing the organic matter and water.
(30) The hydrogen production apparatus according to (23), wherein a voltage between the fuel electrode and the oxidizing electrode and/or a production amount of the hydrogen-containing gas are adjusted by adjusting a concentration of the fuel containing the organic matter and water.
(31) The hydrogen production apparatus according to (25), wherein a voltage between the fuel electrode and the oxidizing electrode and/or a production amount of the hydrogen-containing gas are adjusted by adjusting a concentration of the fuel containing the organic matter and water.
(32) The hydrogen production apparatus according to any one of (11) to (20), wherein the operating temperature is 100 ℃ or lower.
(33) The hydrogen production apparatus according to (32), wherein the operating temperature is 30 to 90 ℃.
(34) The hydrogen production apparatus according to (21), wherein the operating temperature is 100 ℃ or lower.
(35) The hydrogen production apparatus according to (22), wherein the operating temperature is 100 ℃ or lower.
(36) The hydrogen production apparatus according to (23), wherein the operating temperature is 100 ℃ or lower.
(37) The hydrogen production apparatus according to (25), wherein the operating temperature is 100 ℃ or lower.
(38) The hydrogen production apparatus according to (28), wherein the operating temperature is 100 ℃ or lower.
(39) The hydrogen production apparatus according to any one of (11) to (20), wherein the separator is a proton conductive solid electrolyte membrane.
(40) The hydrogen production apparatus according to (39), wherein the proton conductive solid electrolyte membrane is a perfluorocarbonsulfonic acid-based solid electrolyte membrane.
(41) The hydrogen production apparatus according to (32), wherein the separator is a proton conductive solid electrolyte membrane.
(42) The hydrogen production apparatus according to any one of (33) to (38), wherein the separator is a proton conductive solid electrolyte membrane.
(43) The hydrogen generator according to any one of (11) to (20), wherein the catalyst of the fuel electrode is a catalyst in which a Pt — Ru alloy is supported on carbon powder.
(44) The hydrogen generator according to (32), wherein the catalyst of the fuel electrode is a catalyst in which a Pt-Ru alloy is supported on carbon powder.
(45) The hydrogen generator according to any one of (33)to (38), wherein the catalyst of the fuel electrode is a catalyst in which a Pt — Ru alloy is supported on carbon powder.
(46) The hydrogen generator according to item (39), wherein the catalyst of the fuel electrode is a catalyst in which a Pt-Ru alloy is supported on carbon powder.
(47) The hydrogen production apparatus according to any one of (11) to (20), wherein the catalyst of the oxidation electrode is a catalyst in which Pt is supported on carbon powder.
(48) The hydrogen production apparatus according to (32), wherein the catalyst of the oxidation electrode is a catalyst in which Pt is supported on carbon powder.
(49) The hydrogen production apparatus according to any one of (33) to (38), wherein the catalyst of the oxidation electrode is a catalyst in which Pt is supported on carbon powder.
(50) The hydrogen production apparatus according to (39), wherein the catalyst of the oxidation electrode is a catalyst in which Pt is supported on carbon powder.
(51) The hydrogen production apparatus according to (43), wherein the catalyst of the oxidation electrode is a catalyst in which Pt is supported on carbon powder.
(52) The hydrogen production apparatus according to any one of (11) to (20), wherein a circulation device for the fuel containing the organic matter and water is provided.
(53) The hydrogen production apparatus according to (32), wherein a circulation device for the fuel containing the organic matter and water is provided.
(54) The hydrogen production apparatus according to any one of (33) to (38), wherein a circulation device for the fuel containing the organic matter and water is provided.
(55) The hydrogen production apparatusaccording to any one of (11) to (20), wherein a carbon dioxide absorption unit for absorbing carbon dioxide contained in the hydrogen-containing gas is provided.
(56) The hydrogen production apparatus according to (32), wherein a carbon dioxide absorbing unit for absorbing carbon dioxide contained in the hydrogen-containing gas is provided.
(57) The hydrogen production apparatus according to any one of (33) to (38), wherein a carbon dioxide absorption unit for absorbing carbon dioxide contained in the hydrogen-containing gas is provided.
Here, the hydrogen production apparatus used in the hydrogen production methods of (2) to (4) above and the hydrogen production apparatuses of (12) to (14) above have means for supplying a fuel and an oxidant to the hydrogen production cell constituting the hydrogen production apparatus, and the means may use a pump, a blower, or the like. Besides, in the cases of (3) and (13) above, there is a discharge control device for deriving electric energy from the hydrogen production cell; in the cases of (4) and (14) above, there is an electrolysis apparatus for applying electric energy to the hydrogen production cell. In the cases of (2) and (12) described above, it is an open state without the discharge control device for deriving electric energy from the hydrogen production cell and the electrolysis device for applying electric energy to the hydrogen production cell. The hydrogen production method (1) and the hydrogen production apparatus (11) include the hydrogen production methods (2) to (4) and the hydrogen production apparatuses (12) to (14), respectively. Further, these hydrogen production apparatuses have a function of controlling the supply amount or concentration of the fuel and the oxidizing agent and deriving the electric energy (in the case of (3) and (13) above) or applying the electric energy (in the case of (4) and (14) above) by monitoring the voltage (open circuit voltage or operating voltage) of the hydrogen production cell and/or the amount of hydrogen-containing gas generated. Here, the basic structure of a hydrogen production cell constituting a hydrogen production apparatus includes a structure in which a fuel electrode is provided on one surface of a separator and a fuel is supplied to the fuel electrode, and a structure in which an oxidizing electrode is provided on the other surface of the separator and an oxidizing agent is supplied to the oxidizing electrode.
The hydrogen production method and the hydrogen production apparatus according to the present invention can convert fuel at a temperature significantly lower than the conventional conversion temperature, such as room temperature to 100 ℃, and thus have the advantages of requiring less energy for conversion, and having no or very little nitrogen gas mixed into the air and no CO contained in the generated hydrogen-containing gas, thereby enabling a gas having a high hydrogen concentration to be obtained and eliminating the need for a CO removal step.
Further, the hydrogen production method and the hydrogen production apparatus of the present invention can generate hydrogen without supplying electric energy to the hydrogen production cell from the outside, and can generate hydrogen even when there is a device for deriving electric energy or when there is a device for applying electric energy from the outside.
In the case of a device for discharging electric energy, since the electric energy can be used for driving auxiliary machines such as a pump and a blower, the effect is remarkable from the viewpoint of effective utilization of energy.
In the case of a device to which electric energy is applied from the outside, by supplying a small amount of electric energy to the hydrogen production cell from the outside, an effect of generating hydrogen exceeding the input electric energy can be achieved.
In either case, the process control can be performed by monitoring the voltage of the hydrogen production cell and/or the amount of hydrogen-containing gas generated, and the densification of the hydrogen production apparatus can be achieved, thereby achieving the effect of reducing the cost of the method and apparatus.
Drawings
Fig. 1 is a schematic diagram showing an example of a hydrogen production apparatus of the present invention.
Fig. 2 is a schematic diagram of a hydrogen production cell (without supplying electric power from the outside) in example 1.
FIG. 3 is a graph showing the relationship among the air flow rate, the hydrogen generation rate and the open circuit voltage at different temperatures (30 to 70 ℃ C.) (hydrogen production example 1-1).
FIG. 4 is a graph showing the relationship between the open circuit voltage and the hydrogen generation rate at different temperatures (30 to 70 ℃ C.) (hydrogen production example 1-1).
FIG. 5 is a graph showing the relationship (temperature 70 ℃ C.) between the air flow rate, the hydrogen generation rate, and the open circuit voltage at different fuel flow rates (hydrogen production example 1-2).
FIG. 6 is a graph showing the relationship (temperature 70 ℃ C.) between the open circuit voltage and the hydrogen generation rate at different fuel flow rates (hydrogen production example 1-2).
FIG. 7 is a graph showing the relationship (temperature 70 ℃ C.) between the air flow rate, the hydrogen generation rate, and the open circuit voltage at different fuel concentrations (hydrogen production examples 1 to3).
FIG. 8 is a graph showing the relationship (temperature 70 ℃ C.) between the opening voltage and the hydrogen generation rate at different fuel concentrations (hydrogen production examples 1 to 3).
Fig. 9 is a graph showing the relationship between the air flow rate, the hydrogen generation rate, and the open circuit voltage in electrolyte membranes having different thicknesses (hydrogen production examples 1 to 4).
FIG. 10 is a graph showing the relationship between the open circuit voltage and the hydrogen generation rate in the case of electrolyte membranes having different thicknesses (Hydrogen production examples 1 to 4).
FIG. 11 is a graph showing the relationship between the air flow rate, the hydrogen generation rate and the open circuit voltage at different temperatures (30 to 90 ℃ C.) (Hydrogen production examples 1 to 5).
FIG. 12 is a graph showing the relationship between the open circuit voltage and the hydrogen generation rate (oxidizing agent: air) at different temperatures (30 to 90 ℃ C.) (hydrogen production examples 1 to 5).
FIG. 13 is a graph showing the relationship (temperature 50 ℃ C.) between the air flow rate, the hydrogen generation rate, and the open circuit voltage at different fuel flow rates (hydrogen production examples 1 to 6).
FIG. 14 is a graph showing the relationship (temperature 50 ℃ C.) between the open circuit voltage and the hydrogen generation rate at different fuel flow rates (hydrogen production examples 1 to 6).
FIG. 15 is a graph showing the relationship (temperature 50 ℃ C.) between the air flow rate, the hydrogen generation rate, and the open circuit voltage at different fuel concentrations (hydrogen production examples 1 to 7).
FIG. 16 is a graph showing the relationship (temperature 50 ℃ C.) between the opening voltage and the hydrogen generation rate at different fuel concentrations (hydrogen production examples 1 to 7).
FIG. 17 is a graph showing the relationship (temperature 50 ℃ C.) between the flow rate of the oxidizing gas, the hydrogen generation rate, and the open circuit voltage at different oxygen concentrations (hydrogen production examples 1 to 8).
FIG. 18 is a graph showing the relationship (temperature 50 ℃ C.) between the open circuit voltage and the hydrogen generation rate at different oxygen concentrations (hydrogen production examples 1 to 8).
FIG. 19 shows H at different temperatures (30 to 90 ℃ C.)2O2Graphs showing the relationship between the flow rate, the hydrogen generation rate, and the open circuit voltage (hydrogen production examples 1 to 10).
FIG. 20 is a graph showing the relationship between the open-circuit voltage and the hydrogen generation rate at different temperatures (30 to 90 ℃ C.) (oxidizing agent: H)2O2) FIGS. 1 to 10 (Hydrogen production examples).
Fig. 21 is a schematic diagram of a hydrogen production cell (device having electrical energy discharge) in example 2.
FIG. 22 is a graph showing the relationship between the derived current density and the operating voltage (discharge: temperature 50 ℃ C.) at different air flow rates (hydrogen production example 2-1).
FIG. 23 is a graph showing the relationship between operating voltage and hydrogen generation rate (discharge: temperature 50 ℃ C.) at different air flow rates (hydrogen production example 2-1).
FIG. 24 is a graph showing the relationship between the derived current density and the operating voltage (discharge: temperature 30 ℃ C.) at different air flow rates (hydrogen production example 2-2).
FIG. 25 is a graph showing the relationship between operating voltage and hydrogen generation rate (discharge: temperature 30 ℃ C.) at different air flow rates (hydrogen production example 2-2).
FIG. 26 is a graph showing the relationship between the derived current density and the operating voltage (discharge: temperature 70 ℃ C.) at different air flow rates (hydrogen production example 2-3).
FIG. 27 is a graph showing the relationship between operating voltage and hydrogen generation rate (discharge: temperature 70 ℃ C.) at different air flow rates (hydrogen production example 2-3).
FIG. 28 is a graph showing the relationship between the derived current density and the operating voltage (discharge: temperature 90 ℃ C.) at different air flow rates (hydrogen production example 2-4).
FIG. 29 is a graph showing the relationship between operating voltage and hydrogen generation rate (discharge: temperature 90 ℃ C.) at different air flow rates (hydrogen production example 2-4).
FIG. 30 is a graph showing the relationship between the current density and the operating voltage (discharge: air flow rate 50 ml/min) derived at different temperatures.
FIG. 31 is a graph showing the relationship between operating voltage and hydrogen generation rate (discharge: air flow rate 50 ml/min) at different temperatures.
FIG. 32 is a graph showing the relationship between the current density and the operating voltage (discharge: air flow 100 ml/min) derived at different temperatures.
FIG. 33 is a graph showing the relationship between the operating voltage and the hydrogen generation rate (discharge: air flow rate 100 ml/min) at different temperatures.
FIG. 34 is a graph showing the relationship between the current density and the operating voltage (discharge: temperature 50 ℃ C.) derived at different fuel flow rates (hydrogen production examples 2 to 5).
FIG. 35 is a graph showing the relationship between operating voltage and hydrogen generation rate (discharge: temperature 50 ℃ C.) at different fuel flow rates (hydrogen production examples 2 to 5).
FIG. 36 is a graph showing the relationship between the current density and the operating voltage (discharge: temperature 50 ℃ C.) derived for different fuel concentrations (hydrogen production examples 2 to 6).
FIG. 37 is a graph showing the relationship between operating voltage and hydrogen generation rate (discharge: temperature 50 ℃ C.) for different fuel concentrations (hydrogen production examples 2 to 6).
FIG. 38 is a graph showing the relationship between current density and operating voltage (discharge: temperature 50 ℃ C.) derived for different oxygen concentrations (hydrogen production examples 2 to 7).
FIG. 39 is a graph showing the relationship between operating voltage and hydrogen generation rate (discharge: temperature 50 ℃ C.) at different oxygen concentrations (hydrogen production examples 2 to 7).
FIG. 40 is a graph showing the relationship between current density and operating voltage derived at different temperatures (discharge: oxidizing agent H)2O2) (hydrogen production examples 2 to 8).
FIG. 41 shows the relationship between operating voltage and hydrogen generation rate at different temperatures (discharge: oxidizing agent H)2O2) (hydrogen production examples 2 to 8).
Fig. 42 is a schematic diagram of a hydrogen production cell (having a device to which electric energy is applied from the outside) in example 3.
FIG. 43 is a graph showing the relationship between the current density applied and the hydrogen generation rate (charging: temperature 50 ℃ C.) at different air flow rates (hydrogen production example 3-1).
FIG. 44 is a graph showing the relationship between operating voltage and hydrogen generation rate (charging: temperature 50 ℃ C.) at different air flow rates (hydrogen production example 3-1).
FIG. 45 is a graph showing the relationship between the current density applied and the operating voltage (charging: temperature 50 ℃ C.) at different air flow rates (hydrogen production example 3-1).
FIG. 46 is a graph showing the relationship between operating voltage and energy efficiency (charging: temperature 50 ℃ C.) at different air flow rates (hydrogen production example 3-1).
FIG. 47 is a graph showing the relationship between the current density applied and the hydrogen generation rate (charging: temperature 30 ℃ C.) at different air flow rates (hydrogen production example 3-2).
FIG. 48 is a graph showing the relationship between operating voltage and hydrogen generation rate (charging: temperature 30 ℃ C.) at different air flow rates (hydrogen production example 3-2).
FIG. 49 is a graph showing the relationship between operating voltage and energy efficiency (charging: temperature 30 ℃ C.) at different air flow rates (hydrogen production example 3-2).
FIG. 50 is a graph showing the relationship between the current density applied and the hydrogen generation rate (charging: temperature 70 ℃ C.) at different air flow rates (hydrogen production example 3-3).
FIG. 51 is a graph showing the relationship between operating voltage and hydrogen generation rate (charging: temperature 70 ℃ C.) at different air flow rates (hydrogen production example 3-3).
FIG. 52 is a graph showing the relationship between operating voltage and energy efficiency (charging: temperature 70 ℃ C.) at different air flow rates (Hydrogen production example 3-3).
FIG. 53 is a graph showing the relationship between the current density applied and the hydrogen generation rate (charging: temperature 90 ℃ C.) at different air flow rates (hydrogen production example 3-4).
FIG. 54 is a graph showing the relationship between operating voltage and hydrogen generation rate (charging: temperature 90 ℃ C.) at different air flow rates (hydrogen production example 3-4).
FIG. 55 is a graph showing the relationship between operating voltage and energy efficiency (charging: temperature 90 ℃ C.) at different air flow rates (Hydrogen production example 3-4).
FIG. 56 is a graph showing the relationship between the applied current density and the hydrogen generation rate (charging: air flow rate 50 ml/min) at different temperatures.
FIG. 57 is a graph showing the relationship between operating voltage and hydrogen generation rate (charge: air flow rate 50 ml/min) at different temperatures.
FIG. 58 is a graph showing the relationship between operating voltage and energy efficiency (charging: air flow rate 50 ml/min) at different temperatures.
FIG. 59 is a graph showing the relationship between the applied current density and the hydrogen generation rate (charging: temperature 50 ℃ C.) at different fuel flow rates (hydrogen production examples 3 to 5).
FIG. 60 is a graph showing the relationship between operating voltage and hydrogen generation rate (charging: temperature 50 ℃ C.) at different fuel flow rates (hydrogen production example 3-5).
FIG. 61 is a graph showing the relationship between operating voltage and energy efficiency (charging: temperature 50 ℃ C.) at different fuel flow rates (hydrogen production examples 3-5).
FIG. 62 is a graph showing the relationship between the applied current density and the hydrogen generation rate (charging: temperature 50 ℃ C.) at different fuel concentrations (hydrogen production examples 3 to 6).
FIG. 63 is a graph showing the relationship between operating voltage and hydrogen generation rate (charging: temperature 50 ℃ C.) for different fuel concentrations (hydrogen production example 3-6).
FIG. 64 is a graph showing the relationship between operating voltage and energy efficiency (charging: temperature 50 ℃ C.) for different fuel concentrations (hydrogen production examples 3 to 6).
FIG. 65 is a graph showing the relationship between the current density applied and the hydrogen generation rate (charging: temperature 50 ℃ C.) at different oxygen concentrations (hydrogen production examples 3 to 7).
FIG. 66 is a graph showing the relationship between operating voltage and hydrogen generation rate (charging: temperature 50 ℃ C.) at different oxygen concentrations (hydrogen production examples 3 to 7).
FIG. 67 is a graph showing the relationship between operating voltage and energy efficiency (charging: temperature 50 ℃ C.) at different oxygen concentrations (hydrogen production examples 3 to 7).
FIG. 68 is a graph showing the relationship between the current density applied and the hydrogen generation rate at different temperatures (charge: oxidizing agent H)2O2) (hydrogen production examples 3 to 8).
FIG. 69 is a graph showing the operating voltage and the hydrogen generation rate at different temperaturesDegree relationship (charge: oxidant H)2O2) (hydrogen production examples 3 to 8).
FIG. 70 is a graph showing the relationship between operating voltage and energy efficiency at different temperatures (charge: oxidant H)2O2) (hydrogen production examples 3 to 8).
Description of the symbols
10: hydrogen production cell, 11: diaphragm, 12: the fuel electrode is provided with a plurality of fuel electrodes,
13: a flow path for supplying fuel (methanol water) containing organic matter and water,
14: oxidation electrode (air electrode), 15: a flow path for supplying an oxidant (air),
16: fuel pump, 17: air blower, 18: a fuel flow regulating valve is arranged on the fuel tank,
19: air flow rate adjusting valve, 20: fuel tank, 21: the fuel adjusting groove is arranged on the fuel adjusting groove,
22: voltage regulator, 23: gas-liquid separator, 24: a conduit.
Detailed Description
The following illustrates specific embodiments for practicing the present invention.
In particular, the hydrogen production method and the hydrogen production apparatus of the present invention are basically novel, and the following description is merely one embodiment, and the present invention is not limited thereto.
An example of the hydrogen production apparatus of the present invention is shown in FIG. 1. The hydrogen production device is provided with a hydrogen production cell (10) and an auxiliary machine for operating the hydrogen production device.
The hydrogen production cell (10) has the following structure: a fuel electrode (12) is provided on one surface of a membrane (11), and has a flow path (13) for supplying a fuel (methanol aqueous solution) containing organic substances and water to the fuel electrode (12), and an oxidizing electrode (14) is provided on the other surface of the membrane (11), and has a flow path (15) for supplying an oxidizing agent (air) to the oxidizing electrode (14).
As auxiliary equipment for operating the hydrogen production apparatus, a fuel pump (16) for supplying a methanol aqueous solution to the fuel electrode (12) and an air blower (17) for supplying air to the oxidizing electrode (14) are provided.
The flow path (13) of the fuel electrode is connected to a fuel pump (16) through a flow control valve (18) by a pipe, and the flow path (15) of the oxidation electrode is connected to an air blower (17) through a flow control valve (19).
The fuel (100% methanol) is stored in a fuel tank (20), transferred to a fuel adjustment tank (21), mixed with water in the fuel adjustment tank (21), adjusted to a methanol aqueous solution of about 3%, for example, and supplied to a fuel electrode (12).
In the hydrogen production apparatus having the above-described configuration, when the fuel pump (16) and the air blower (17) are operated by supplying electric power and the flow rate control valve (18) is opened, the fuel pump (16) supplies the methanol aqueous solution from the fuel control tank (21) to the fuel electrode (12) through the flow path (13); when the flow rate control valve (19) is opened, air is supplied to the oxidation electrode (14) through the flow path (15) by an air blower (17).
This causes a reaction to occur between the fuel electrode and the oxidizing electrode (air electrode) as described later, and generates a hydrogen-containing gas from the fuel electrode (12) side.
Further, the amount of hydrogen-containing gas generated can be adjusted by providing a voltage regulator (22) for monitoring the voltage (open circuit voltage or operating voltage) of the hydrogen generation cell (10) and controlling the supply amount or concentration of fuel and air and the derived electric energy or applied electric energy.
The produced hydrogen-containing gas is separated into a hydrogen-containing gas and an unreacted aqueous methanol solution by a gas-liquid separator (23), and part or all of the unreacted aqueous methanol solution is circulated by a circulation means constituted by a conduit (24) returned to the fuel adjusting tank (21). Water may be supplied from outside the system according to circumstances.
The hydrogen production cell constituting the hydrogen production apparatus of the present invention has the following basic structure as described above: a diaphragm (11), a fuel electrode (12) provided on one surface of the diaphragm (11), and an oxidation electrode (14) provided on the other surface. For example, as such a structure, an MEA (electrolyte/electrode assembly) such as that used in a direct methanol fuel cell can be used.
The MEA can be produced by a method similar to the conventional method in which the fuel electrode and the oxidation electrode (air electrode) are bonded to both surfaces of the separator by hot pressing, but the method is not limited thereto.
The separator may use a proton conductive solid electrolyte membrane used as a polymer electrolyte membrane in a fuel cell. As the proton conductive solid electrolyte membrane, a perfluorocarbon sulfonic acid membrane having a sulfonic acid group such as Nafion membrane available from dupont is preferably used.
The fuel electrode and the oxidizing electrode (air electrode) are preferably electrodes having conductivity and catalytic activity, and can be produced, for example, by applying a catalyst slurry containing a catalyst in which a noble metal is supported on a carrier made of carbon powder or the like, a binder such as PTFE resin, and a substance imparting ionic conductivity such as Nafion solution on a gas diffusion layer and drying the catalyst slurry.
The gas diffusion layer is preferably a layer made of hydrophobic carbon paper (carbon paper) or the like.
Any fuel electrode catalyst may be used, but a catalyst in which a Pt — Ru alloy is supported on carbon powder is preferably used.
In the hydrogen production apparatus having the above configuration, when a fuel containing an organic substance such as a methanol aqueous solution is supplied to the fuel electrode and an oxidizing agent such as air, oxygen, or hydrogen peroxide is supplied to the oxidizing electrode (air electrode), a hydrogen-containing gas is generated at the fuel electrode under specific conditions.
The hydrogen production method and the hydrogen production method in the hydrogen production apparatus of the present invention are completely different from the conventional hydrogen production method, and it has been difficult to explain the mechanism thereof. The following explains that the possibility of generating a completely new reaction cannot be denied by the conventional presumption.
In the hydrogen production method and the hydrogen production apparatus of the present invention, as described later, the hydrogen-containing gas is generated from the fuel electrode side to which methanol and water are supplied at a low temperature of 30 to 90 ℃. A gas having a hydrogen concentration of about 70 to 80% is generated without supplying electric energy to the hydrogen generation cell from the outside; in the case where electric energy is applied to the hydrogen production cell from the outside, gas having a hydrogen concentration of 80% or more is generated. It is also known that the generation of this gas depends on the open circuit voltage or operating voltage of both poles. From these results, the following mechanism of hydrogen generation is presumed. Hereinafter, the mechanism will be described under an open circuit condition for the sake of simplicity.
For example, when methanol is used as a fuel in the hydrogen production method and the hydrogen production apparatus of the present invention, it is considered that protons are first generated at the fuel electrode by a catalyst, as in the case of the direct methanol fuel cell.
……(1)
In the case of using Pt — Ru as a catalyst, it is considered that the reaction (1) is carried out by adsorbing methanol on the Pt surface, sequentially causing electrochemical oxidation reactions as described below, and generating adsorbed chemical species strongly adsorbed on the surface (published by pill corporation, page 406, 2/20, 2001, third edition).
If the Pt- (CO) ads is to be further oxidized, OH adsorption by water is required.
In the case of a direct methanol fuel cell, H is generated at the fuel electrode by the reaction of formula (1)+The (protons) move in the proton-conductive solid electrolyte membrane, and react with the oxygen-containing gas or oxygen supplied to the oxidation electrode at the oxidation electrode as follows.
……(2)
The hydrogen production method and the hydrogen production apparatus of the present invention are characterized in that e is generated by the reaction of formula (1) in the case of an open circuit-The reaction is not supplied to the oxidation electrode through an external circuit, and thus in order to generate the reaction of formula (2), it is necessary to generate another reaction at the oxidation electrode and supply e-。
On the other hand, in the case of using a proton conductive solid electrolyte membrane such as Nafion in a direct methanol fuel cell, CH is known3The "crossover" phenomenon of OH permeation from the fuel electrode to the oxidant electrode side. The following cross-methanol electrolytic oxidation reaction is likely to occur in the oxidation.
……(3)
If the reaction of formula (3) takes place, e is formed by this reaction-When supplied, the reaction of formula (2) occurs.
Subsequently, H produced bythe reaction of formula (3)+The hydrogen moves through the proton conductive solid electrolyte membrane, and the following reaction occurs at the fuel electrode, thereby generating hydrogen.
……(4)
Here, H is generated at the fuel electrode by the reaction of formula (1)+And e-Movement to the oxidation electrode and H generated in the oxidation electrode by the reaction of formula (3)+And e-The movements to the fuel pole are considered to apparently cancel each other out.
In this case, it is presumed that H is generated by the reaction of the formula (3) at the oxidation electrode+And e-The reaction of the formula (2) is caused, and H is generated at the fuel electrode by the reaction of the formula (1)+And e-reaction to give formula (4).
Assuming that the reactions of expressions (1) and (4) are performed on the fuel electrode and the reactions of expressions (2) and (3) are performed on the oxidation electrode, it is considered that the following expression (5) holds as a whole.
……(5)
The theoretical efficiency of the reaction was 59% (exotherm for 3mol hydrogen/exotherm for 2mol methanol).
However, in the above reaction, the standard electrode potential E0 of the reaction of formula (1) is 0.046V, and the standard electrode potential E0 of the reaction of formula (4) is 0.0V, and when the two are combined in a standard state, the reaction of formula (1) proceeds to the left because formula (1) corresponds to the positive electrode and formula (4) corresponds to the negative electrode, and the reaction of formula (4) also proceeds to the left, and therefore hydrogen is not generated.
Here, in order to cause the reaction of the formula (1) to proceed to the right side as well as the reaction of the formula (4) to proceed to the right side, it is necessary to cause the formula (1) to correspond to the negative electrode and the formula (4) to correspond to the positive electrode, and if the entire fuel electrode is equipotential, it is necessary to shift the methanol oxidation potential to the low potential side or shift the hydrogen generation potential to the high potential side.
However, in the case where the fuel electrode is not equipotential, H is generated from methanol and water in the fuel electrode+Reaction of formula (1) and H+And e-The reaction of formula (4) in combination with the formation of hydrogen may be carried out simultaneously.
As described in the following examples, when the operating temperature is high, reaction heat from the outside is supplied, and the reactions of formulae (1) and (3) as endothermic reactions proceed to the right, from the viewpoint that hydrogen is easily generated.
In addition to the reactions of formulae (1) and (3), methanol permeated from the fuel electrode causes the following side reaction oxidized by oxygen on the surface of the air electrode catalyst due to the crossover phenomenon.
……(6)
Since the reaction of formula (6) is an exothermic reaction, it is understood that the heat of the reactions of formulae (1) and (3) is supplied by the heat generation.
Method for producing hydrogen and method for producing hydrogen according to inventions recited in claims 2 and 12 of the present applicationIn the case of device fabrication (hereinafter referred to as "open circuit condition"), as will be understood from the examples described later, if the supply amount of oxygen (air) is reduced and the open circuit voltage reaches 300 to 800mVIt is presumed that the oxidation of methanol permeating the air electrode side by the formula (6) is suppressed and the generation of hydrogen by the formula (3) H+The generation reaction becomes dominant, and hydrogen is generated by the reaction of formula (4).
In the case of the hydrogen production method and the hydrogen production apparatus according to the inventions of claims 3 and 13 of the present application (hereinafter referred to as "discharge conditions"), it is considered that hydrogen is produced by a mechanism similar to the hydrogen production mechanism under the open circuit condition. However, unlike the case of the open-circuit condition, the amount of H corresponding to the discharge current is large+Since it is necessary to maintain the electrically neutral condition of the entire cell while moving from the fuel electrode to the oxidation electrode, it is considered that the reaction of the formula (1) on the fuel electrode is superior to the reaction of the formula (4) and the reaction of the formula (2) on the oxidation electrode is superior to the reaction of the formula (3).
As will be understood from the examples described later, the discharge current becomes large (e is supplied to the maximum oxidation amount)-) When the discharge voltage is less than 200mV, it is assumed that hydrogen is not generated because the voltage necessary for the electrolysis of the methanol aqueous solution is not reached.
Further, it is presumed that hydrogen is not generated even when oxygen (air) is supplied in a large amount or when the discharge voltage is higher than 600mV, since methanol permeating the air electrode sideis oxidized by the formula (6), H in the formula (3) is not generated+And (4) generating reaction.
On the other hand, when the amount of oxygen (air) supplied is small, if the discharge current is reduced and the discharge voltage (operating voltage) is 200 to 600mV, hydrogen is generated, which is presumed to inhibit the oxidation of methanol permeating the air electrode side by the formula (6), and the H of the formula (3) is oxidized+The generation reaction becomes dominant, and hydrogen is generated by the reaction of formula (4).
In the case of the hydrogen production method and the hydrogen production apparatus according to the inventions of claims 4 and 14 of the present application (hereinafter referred to as "charging conditions"), it is also considered that hydrogen is produced by a mechanism similar to the hydrogen production mechanism under the open-circuit condition. However, unlike the case of open circuit conditions, due to the amount of H equivalent to the electrolysis current+Since the fuel electrode moves from the oxidizing electrode to the fuel electrode, it is necessary to maintain the electrically neutral condition of the entire cell, and it is considered that the cell is maintained at the electrically neutral conditionThe reaction of formula (4) on the fuel electrode is superior to that of formula (1), and the reaction of formula (3) on the oxidation electrode is superior to that of formula (2).
That is, in the case of the charging condition of the present invention, the electric energy is applied from the outside (e is supplied from the outside to the fuel electrode) by using the fuel electrode as the cathode and the oxidizing electrode as the anode-) Basically, the electrolysis occurs, and as will be understood from the examples described later, if the applied electric energy (applied voltage) is increased, a large amount of hydrogen is generated, which results in the generation of hydrogenCan be considered as e supplied from the outside to the fuel electrode-The electrolytic oxidation reaction of methanol represented by the formula (3) and the reaction represented by the formula (4) are promoted in a larger amount 。
However, as described later, when the supply amount of oxygen (air) is small and the applied voltage (operating voltage) is in a low range of 400 to 600mV, the energy efficiency increases. It is presumed that, in this range, as described above, in the case of the open circuit condition or the discharge condition in which electric energy is not supplied from the outside, the oxidation of methanol permeating the air electrode side by the formula (6) is also suppressed, and the H of the formula (3) is+The formation reaction becomes dominant, and then H of the formula (4) is passed+The formation reaction produces hydrogen; in the case of the charging condition, hydrogen is generated in the same manner as in the case of the open circuit condition or the discharging condition, except for a portion to which electric energy is applied from the outside.
Here, the meaning of the potential of the battery will be described. Generally, the voltage of a cell having gas electrodes formed on both sides of an electrolyte membrane is generated by a difference in chemical potential between the electrodes of ions that are electrically conducted in the electrolyte.
That is, when polarization of both electrodes is not considered, since a proton (hydrogen ion) conductive solid electrolyte membrane is used as an electrolyte, the observed voltage represents a difference in chemical potential of hydrogen, so-called hydrogen partial pressure, of the battery at both electrodes.
In the present invention,as described in the later embodiment, when the voltage between the fuel electrode and the oxidizing electrode is in a certain range, hydrogen is generated from the fuel electrode side; when the difference in chemical potential between hydrogen at both electrodes is within a certain range, it is estimated that the reactions of the above-mentioned formulae (1) to (6) proceed to generate hydrogen.
The hydrogen production method and the hydrogen production apparatus according to the present invention can adjust the amount of hydrogen-containing gas generated by adjusting the voltage (open circuit voltage or operating voltage) between the fuel electrode and the oxidant electrode (air electrode) in both the case where electric energy is not taken out from the hydrogen production cell to the outside and the case where electric energy is not supplied from the outside to the hydrogen production cell, the case where electric energy is taken out from the hydrogen production cell to the outside, and the case where electric energy is applied from the outside to the hydrogen production cell.
As is clear from the examples described later, hydrogen is generated at an open circuit voltage of 300 to 800mV under open circuit conditions; under the discharge condition, the discharge voltage (operating voltage) is 200-600 mV to generate hydrogen; in the case of the charging condition, the applied voltage (operating voltage) is 300 to 1000mV (energy efficiency is high at 400 to 600 mV) to generate hydrogen, and therefore, the amount of hydrogen-containing gas generated can be adjusted by adjusting the open circuit voltage or the operating voltage within this range.
As shown in the following examples, the open circuit voltage or the operating voltage and/or the amount of hydrogen-containing gas generated (hydrogen generation rate) can be adjusted by adjusting the amount of the oxidant (oxygen-containing gas oroxygen gas, liquid containing hydrogen peroxide) supplied, adjusting the concentration of the oxidant (oxygen concentration in the oxygen-containing gas), adjusting the amount of the fuel containing organic matter supplied, and adjusting the concentration of the fuel containing organic matter.
In addition to the above, in the case of the discharge condition, the electric energy to be discharged to the outside (the electric current to be discharged to the outside is adjusted, and the voltage to be discharged to the outside is adjusted by using a power source capable of controlling a constant voltage, that is, a so-called potentiostat), and in the case of the charge condition, the operation voltage and/or the amount of the hydrogen-containing gas to be generated can be adjusted by adjusting the electric energy to be applied (the electric current to be applied is adjusted, and the voltage to be applied is adjusted by using a power source capable of controlling a constant voltage, that is, a so-called potentiostat).
In the hydrogen production method and the hydrogen production apparatus of the present invention, since the fuel containing the organic matter can be decomposed at 100 ℃ or lower, the operating temperature of the hydrogen production apparatus can be set to 100 ℃ or lower. The operating temperature is preferably 30 to 90 ℃. By adjusting the operating temperature in the range of 30 to 90 ℃, the open circuit voltage or the operating voltage and/or the amount of hydrogen-containing gas generated can be adjusted as described in the following examples.
Further, the present invention is advantageous in that, in the conventional conversion technology requiring operation at 100 ℃ or higher, water is converted into steam to gasify the fuel containing organic matter, and under such conditions, even if hydrogen is generated, a separate hydrogen separation facility must be separately employed.
However, although the above-mentioned disadvantages are present if the fuel containing organic substances is decomposed at a temperature of 100 ℃ or higher, the present invention does not deny that the hydrogen generator of the present invention can be operated even at a constant temperature exceeding 100 ℃.
From the viewpoint of the presumed principle, the fuel containing an organic substance may be a liquid or gas fuel which is electrochemically oxidized through a proton conductive membrane to generate protons, and a liquid fuel containing an alcohol such as methanol is preferable. Since the fuel containing the organic matter is supplied together with water, a solution containing alcohol and water is preferable, and an aqueous solution containing methanol is particularly preferable. Here, the methanol-containing aqueous solution as an example of the fuel is a solution containing at least methanol and water, and the concentration thereof can be arbitrarily selected in the region where the hydrogen-containing gas is generated.
As the oxidizing agent, a gaseous or liquid oxidizing agent can be used. Oxygen-containing gas or oxygen is preferred as the gaseous oxidizing agent. The oxygen concentration of the oxygen-containing gas is particularly preferably 10% or more. Preferably, a liquid containing hydrogen peroxide is used as the liquid oxidizing agent.
In the present invention, since the fuel charged into the hydrogen production apparatus is consumed in one operation in the apparatus and the rate of decomposition into hydrogen is low, it is preferable to provide a fuel circulation device to increase the conversion rate into hydrogen.
The hydrogen production apparatus of the present invention includes a device for extracting a hydrogen-containing gas from the fuel electrode side, and is a device for recovering hydrogen, and preferably also recovers carbon dioxide. Since the operation is performed at a low temperature of 100 ℃ or lower, a carbon dioxide absorbing unit for absorbing carbon dioxide contained in the hydrogen-containing gas can be provided by a simple method.
Although examples of the present invention (hydrogen production examples) will be described below, the proportions of the catalyst, PTFE, Nafion, and the like, and the thicknesses of the catalyst layer, the gas diffusion layer, the electrolyte membrane, and the like may be appropriately changed, and the present invention is not limited to these examples.
Example 1
An example of a case where hydrogen is produced by the hydrogen production method and the hydrogen production apparatus (open circuit condition) according to the inventions of claims 2 and 12 of the present application will be described below.
Hydrogen production example 1-1
The hydrogen production cell in example 1 (production examples 1-1 to 1-10) had the same structure as a representative direct methanol fuel cell.
Fig. 2 schematically shows the hydrogen production cell.
That is, a proton conductive electrolyte membrane (Nafion115) manufactured by dupont was used as an electrolyte, carbon paper (manufactured by imperial レ) was immersed in a polytetrafluoroethylene dispersion liquid having a concentration of 5%, and then fired at 360 ℃ to perform a hydrophobic treatment, and an air electrode catalyst slurry prepared by mixing an air electrode catalyst (platinum-carrying carbon, manufactured by precious metal in paddy), PTFE fine powder, and a 5% Nafion solution (manufactured by アルドリツチ) was coated on one surface of the carbon paper to form a gas diffusion layer with an air electrode catalyst on an air electrode. The weight ratio of theair electrode catalyst, the PTEF and the Nafion is 65 percent to 15 percent to 20 percent. The amount of the catalyst in the air electrode thus prepared was 1mg/cm in terms of platinum2。
Further, the carbon paper was subjected to a hydrophobic treatment by the same method, and then a fuel electrode catalyst slurry prepared by mixing a fuel electrode catalyst (carbon supporting Pt — Ru, manufactured by precious metal in paddy) with a PTFE fine powder and a 5% Nafion solution was coated on one surface thereof, thereby forming a gas diffusion layer with a fuel electrode catalyst. The weight ratio of the fuel electrode catalyst, the PTEF and the Nafion is 55 percent to 15 percent to 30 percent. The amount of catalyst of the fuel electrode thus produced was converted to Pt-RuIs 1mg/cm2。
The electrolyte membrane, the gas diffusion layer with the air electrode catalyst and the gas diffusion layer with the fuel electrode catalyst were mixed at 40 ℃ and 100kg/cm2The MEA is produced by thermocompression bonding. Thus making itThe effective electrode area of the MEA of (1) was 60.8cm2. The thicknesses of the catalyst layers of the air electrode and the fuel electrode and the gas diffusion layers of the air electrode and the fuel electrode after fabrication were about 30 μm and 170 μm, respectively, and were substantially the same.
The MEA is sandwiched between an air electrode separator and a fuel electrode separator made of graphite impregnated with a phenol resin to prevent gas leakage, thereby constituting a single cell. In addition, in order to prevent leakage of fuel and air, a silicone rubber package is provided at the peripheral portion of the MEA.
The hydrogen producing cell thus produced was placed in a hot air circulation type electric furnace, air was flowed at a flow rate of 0 to 400 ml/min at the air electrode side and 0.5 to 2M of an aqueous methanol solution (fuel) was flowed at a flow rate of 2 to 15 ml/min at a cell temperature (operating temperature) of 30 to 70 ℃, and the voltage difference (open circuit voltage) between the fuel electrode and the air electrode, the amount of gas generated at the fuel electrode side, and the gas composition at this time were examined.
First, the flow rate of the methanol aqueous solution (fuel) supplied to the cell was kept constant at 8 ml/min, and the amount of gas generated from the fuel electrode side was measured by changing the air flow rate at each temperature of 30 ℃, 50 ℃ and 70 ℃. The amount of gas generated was measured by the underwater displacement method. The hydrogen concentration in the generated gas was analyzed by gas chromatography to determine the hydrogen generation rate.
The results are shown in FIG. 3.
Thus, it was confirmed that hydrogen was generated from the fuel electrode side of the cell by reducing the air flow rate at each temperature. It is also understood that the higher the temperature, the higher the hydrogen generation rate. Further, the relationship between the air flow rate and the open circuit voltage of the battery was investigated, and it was found that the open circuit voltage of the battery tended to decrease with a decrease in the air flow rate.
In fig. 4, the results of fig. 3 are organized as the relationship between the open circuit voltage and the hydrogen generation rate.
From this, it is found that the hydrogen generation rate (hydrogen generation amount) tends to depend on the open circuit voltage, and hydrogen is generated at an open circuit voltage of 400 to 600 mV. In addition, a peak of the hydrogen generation rate was observed at around 450mV at any temperature.
Then, a gas was generated under the conditions of a temperature of 70 ℃, a fuel flow rate of 8 ml/min and an air flow rate of 120 ml/min, and the hydrogen concentration in the gas was measured by gas chromatography.
As a result, it was confirmed that the generated gas contained about 70% of hydrogen and about 15% of carbon dioxide. In addition, no CO was detected.
Hydrogen production examples 1 and 2
Next, the air flow rate was changed under the conditions of a cell temperature of 70 ℃ and a flow rate of a methanol aqueous solution (fuel) having a concentration of 1M of 2, 8 and 15 ml/min, and the relationship among the fuel flow rate, the air flow rate, the hydrogen generation rate and the open circuit voltage of the cell at this time is shown in fig. 5.
From this, it is understood that the hydrogen generation rate is high when the fuel flow rate is small.
In fig. 6, the results of fig. 5 are organized as the relationship between the open circuit voltage and the hydrogen generation rate.
From this, it is understood that the hydrogen generation rate under each condition depends on the open circuit voltage. In any fuel flow rate, a peak of the hydrogen generation rate was observed at around 450mV in the same manner as in Hydrogen production example 1-1.
Further, in this production example, the hydrogen concentration in the produced gas was determined by gas chromatography under the conditions (operation temperature 70 ℃, fuel concentration 1M, fuel flow rate 2 ml/min, and air flow rate 100 ml/min) at which the open circuit voltage 442mV at the maximum hydrogen generation rate of 14.48 ml/min was obtained, similarly to hydrogen production example 1-1, and the result was about 70%.
Hydrogen production examples 1 to 3
Next, the air flow rate was changed under the conditions of a cell temperature of 70 ℃, a constant flow rate of an aqueous methanol solution (fuel) of 8 ml/min, and fuel concentrations of 0.5, 1, and 2M, and the relationships among the fuel flow rate, the air flow rate, the hydrogen generation rate, and the open circuit voltage of the cell at this time are shown in fig. 7.
From this, it is understood that the hydrogen generation rate is high when the fuel concentration is low.
In fig. 8, the results of fig. 7 are organized as the relationship between the open circuit voltage and the hydrogen generation rate.
From this, it is found that the hydrogen generation rate under each condition depends on the open circuit voltage, and hydrogen is generated at 300 to 600 mV. In any fuel concentration, a peak of the hydrogen generation rate was observed at around 450mV in the same manner as in Hydrogen production example 1-1.
Hydrogen production examples 1 to 4
Next, the influence of the thickness of the electrolyte membrane on the amount of gas generated was investigated.
In hydrogen production examples 1-1 to 1-3, Nafion115 (thickness: 130 μ M) manufactured by dupont was used as an electrolyte membrane, a similar hydrogen production cell was formed using Nafion112 (thickness: 50 μ M) manufactured by dupont, and the relationship between the fuel flow rate, the air flow rate, the hydrogen generation rate, and the open circuit voltage of the cell was examined by changing the air flow rate under the conditions of a temperature of 70 ℃, a fuel concentration of 1M, and a fuel flow rate of 8 ml/min.
Nafion115 and Nafion112 are the same material, and the influence of the thickness of the electrolyte membrane is studied purely here. The results of the study are shown in FIG. 9.
In fig. 10, the results of fig. 9 are collated as the relationship between the open circuit voltage and the hydrogen generation rate.
From this, it is understood that the hydrogen generation rates are substantially equal for any electrolyte membrane. As can be seen from the graph, the hydrogen generation rate under each condition depends on the open circuit voltage, and a peak of the hydrogen generation rate is observed even in the vicinity of 450 mV.
Hydrogen production examples 1 to 5
The hydrogen production cell similar to that of hydrogen production example 1-1 was used, and the open circuit voltage and the hydrogen production rate at the fuel electrode side were examined by placing the hydrogen production cell in a hot air circulation type electric furnace, flowing air at a flow rate of 0 to 250 ml/min on the air electrode side and 1M aqueous methanol (fuel) at a flow rate of 5 ml/min on the fuel electrode side at a cell temperature of 30 ℃, 50 ℃, 70 ℃ and 90 ℃.
Fig. 11 shows the relationship between the air flow rate and the hydrogen generation rate.
As in the case of hydrogen production example 1-1, it was confirmed that hydrogen was produced from the fuel electrode side of the cell by reducing the air flow rate at each temperature. It is also understood that the higher the temperature, the higher the hydrogen generation rate. Further, the relationship between the air flow rate and the open circuit voltage of the battery was examined, and it was confirmed that the open circuit voltage of the battery tended to decrease with a decrease in the air flow rate.
In fig. 12, the results of fig. 11 are organized as the relationship between the open circuit voltage and the hydrogen generation rate.
It isthus found that the hydrogen generation rate depends on the open circuit voltage, and hydrogen is generated at 300 to 700 mV. In addition, a peak of hydrogen generation rate is observed at about 470-480 mV at 30-70 ℃; a peak in the hydrogen generation rate was observed at around 440mV at 90 ℃.
Hydrogen production examples 1 to 6
The relationship among the fuel flow rate, the air flow rate, and the hydrogen generation rate at this time is shown in fig. 13, in which the air flow rate was changed under the conditions of a cell temperature of 50 ℃, a fuel flow rate of 1.5, 2.5, 5.0, 7.5, and 10.0 ml/min, using the same hydrogen production cell as in hydrogen production example 1-1.
From this, it is found that, unlike the results of 70 ℃ in the above-described hydrogen production examples 1-2, the hydrogen generation rate tends to increase when the fuel flow rate is large.
In fig. 14, the results of fig. 13 are organized as the relationship between the open circuit voltage and the hydrogen generation rate.
From this, it is found that the hydrogen generation rate under each condition depends on the open circuit voltage, and hydrogen is generated at 300 to 700 mV. In addition, a peak of the hydrogen generation rate was observed in the vicinity of 450 to 500 mV.
The methanol consumption amount and the hydrogen generation rate in the fuel at the time of changing the fuel flow rate are calculated, and the energy efficiency under the open-circuit condition (which is different from the energy efficiency under the charging condition calculated by the calculation formula described later) is calculated using the following formula. As a result, the energy efficiency under the open-circuit condition was 17% at a fuel flow rate of 5.0 ml/min and 22% at 2.5 ml/min.
Energy efficiency of open-circuit condition (%)
X 100 (standard enthalpy change of hydrogen produced/enthalpy change of methanol consumed) x 100
Hydrogen production examples 1 to 7
Using a hydrogen production cell similar to that of hydrogen production example 1-1, the air flow rate was changed under conditions of a cell temperature of 50 ℃, a constant flow rate of 5 ml/min of an aqueous methanol solution (fuel), and fuel concentrations of 0.5, 1, 2, and 3M, and the relationship between the air flow rate and the hydrogen production rate at this time is shown in fig. 15.
As the fuel concentration decreases, the air flow rate becomes smaller, and a peak of the hydrogen generation rate is observed.
In fig. 16, the results of fig. 15 are organized as the relationship between the open circuit voltage and the hydrogen generation rate.
From this, it is found that the hydrogen generation rate under each condition depends on the open circuit voltage, and hydrogen is generated at 300 to 700 mV. In addition, a peak of the hydrogen generation rate was observed at about 470mV for any fuel concentration.
Hydrogen production examples 1 to 8
Using a hydrogen production cell similar to that of hydrogen production example 1-1 (except that the air electrode forms an oxidation electrode through which an oxidizing gas flows), the flow rates of the oxidizing gases were changed under conditions of a cell temperature of 50 ℃, a fuel concentration of 1M, a fuel flow rate of 5 ml/min, and oxygen concentrations of 10, 21, 40, and 100%, and the relationship between the flow rates of the oxidizing gases and the hydrogen generation rates at that time is shown in fig. 17. Here, air was used as the gas having an oxygen concentration of 21%, a gas prepared by mixing nitrogen gas with air was used as the gas having an oxygen concentration of 10%, and a gas prepared by mixing oxygen gas with air (oxygen gas concentration 100%) was used as the gas having an oxygen concentration of 40%.
As the oxygen concentration increases, the oxidizing gas flow rate decreases, and a peak in the hydrogen generation rate is observed.
Fig. 18 collates the results of fig. 17 as the relationship between the open circuit voltage and the hydrogen generation rate.
From these results, it is found that the hydrogen generation rate under each condition depends on the open circuit voltage, and hydrogen is generated at 400 to 800 mV. In addition, a peak in the hydrogen generation rate was observed in the vicinity of 490 to 530 mV.
Hydrogen production examples 1 to 9
Using a hydrogen production cell similar to that of hydrogen production example 1-1, gas was generated by flowing air at a flow rate of 60 ml/min on the air electrode side and 1M aqueous methanol (fuel) at a flow rate of 2.6 ml/min on the fuel electrode side at a cell temperature of 50 ℃, 200cc was sampled, and the CO concentration in the gas was measured using gas chromatography. As a result, CO (1 ppm or less) was not detected from the sample. Here, the cell open circuit voltage under this condition was 477mV, and the hydrogen generation rate was about 10 ml/min.
Hydrogen production examples 1 to 10
A hydrogen production cell similar to that in hydrogen production example 1-1 (except that the air electrode forms an oxidation electrode for flowing liquid hydrogen peroxide) was used, and the hydrogen production cell was placed in a hot air circulation type electric furnace, and the flow rate of 1 to 8 ml/1M H was flowed on the oxidation electrode sideat a cell temperature of 30 ℃, 50 ℃, 70 ℃ and 90 ℃2O2(Hydrogen peroxide), 1M aqueous methanol (fuel) was flowed at a flow rate of 5 ml/min on the fuel electrode side, and the open circuit voltage of the cell and the hydrogen generation rate generated on the fuel electrode side at that time were examined.
In FIG. 19 is shown as H2O2The relationship between the flow rate and the hydrogen generation rate.
As in the case of Hydrogen production example 1-1, H was reduced at each temperature2O2The flow rate of hydrogen generated from the fuel electrode side of the cell was confirmed. It is also understood that the higher the temperature, the higher the hydrogen generation rate. Further, H was investigated2O2The relationship between the flow rate and the open circuit voltage of the battery was confirmed as follows H2O2The decrease in the flow rate tends to lower the open circuit voltage of the battery.
In fig. 20, the results of fig. 19 are organized as the relationship between the open circuit voltage and the hydrogen generation rate.
From these results, it is found that the hydrogen generation rate tends to depend on the open circuit voltage, and hydrogen is generated at an open circuit voltage of 300 to 600 mV. In addition, a peak of hydrogen generation rate was observed at about 500mV at 30-50 ℃; a peak in the hydrogen generation rate was observed at about 450mV at 70-90 ℃.
It is important here that in example 1 described above, all the current or voltage is not applied to the hydrogen production cell from the outside, and only the open-circuit voltage is measured by a potentiometer having an internal resistance of 1G Ω or more, while only the fuel and the oxidant are supplied.
In other words, with the hydrogen production cell of example 1, a part of the fuel can be converted into hydrogen without supplying energy from the outside other than supplying the fuel and the oxidant.
Further, it is converted at an extremely low temperature of 30 to 90 ℃ and is considered to be an unprecedented new hydrogen production method and hydrogen production apparatus.
Example 2
An example of a case where hydrogen is produced by the hydrogen production method and the hydrogen production apparatus (discharge conditions) according to the inventions of claims 3 and 13 of the present application is shown below.
Hydrogen production example 2-1
FIG. 21 is a schematic diagram of a hydrogen production cell having an electric energy discharge device in example 2 (production examples 2-1 to 2-8).
The structure of the hydrogen production cell of hydrogen production example 1-1 was the same except that the fuel electrode was a negative electrode and the air electrode was a positive electrode, to thereby provide a device for discharging electric energy.
The hydrogen production cell was installed in a hot air circulation type electric furnace, and at a cell temperature (operating temperature) of 50 ℃, air was flowed at a flow rate of 10 to 100 ml/min on the air electrode side, and a 1M methanol aqueous solution (fuel) was flowed at a flow rate of 5 ml/min on the fuel electrode side, and at this time, the operating voltage between the fuel electrode and the air electrode, the amount of gas generated on the fuel electrode side, and the gas composition were examined while changing the current flowing between the air electrode and the fuel electrode. The hydrogen concentration in the generated gas was analyzed by gas chromatography to determine the hydrogen generation rate.
Fig. 22 shows the relationship between the current density and the operating voltage derived in this test.
As the air flow rate becomes smaller, the operating voltage decreases, and a decrease in dischargeable limiting current density is observed.
In fig. 23, the results of fig. 22 are organized as the relationship between the operating voltage and the hydrogen generation rate.
From this, it is found that the hydrogen generation rate (hydrogen generation amount) tends to depend on the operating voltage, and that gas is generated at an operating voltage of 300 to 600 mV. It is also found that hydrogen is most easily generated when the air flow rate is 50 to 60 ml/min. Further, when the air flow rate is larger than this, hydrogen is hardly generated, and when it is 100 ml/min, hydrogen is hardly generated.
Then, at a high hydrogen generation rate, a temperature of 50 ℃, a fuel flow rate of 5 ml/min, an air flow rate of 60 ml/min, and a current density of 8.4mA/cm2Gas was generated under the conditions of (1), and the hydrogen concentration in the gas was measured by gas chromatography.
As a result, the generated gas contained about 74% of hydrogen, and the hydrogen generation rate was 5.1 ml/min. In addition, no CO was detected.
Hydrogen production example 2-2
Using a hydrogen production cell similar to that of hydrogen production example 2-1, the operating voltage of the fuel electrode and the air electrode and the generation rate of hydrogen generated at the fuel electrode were examined while changing the current flowing between the air electrode and the fuel electrode at the time of flowing air at a flow rate of 30 to 100 ml/min at a cell temperature of 30 ℃ and flowing a 1M methanol aqueous solution (fuel) at aflow rate of 5 ml/min at the fuel electrode.
Fig. 24 shows the relationship between the current density and the operating voltage derived in this test.
As the air flow rate becomes smaller, the operating voltage decreases, and a decrease in dischargeable limiting current density is observed.
In fig. 25, the results of fig. 24 are organized as the relationship between the operating voltage and the hydrogen generation rate.
From this, it is found that the hydrogen generation rate tends to depend on the operating voltage, and hydrogen is generated at an operating voltage of 200 to 540 mV. It is also found that hydrogen is generated at an air flow rate of 30 to 70 ml/min. At 100 ml/min, almost no hydrogen was produced.
Hydrogen production examples 2 to 3
Using a hydrogen production cell similar to that of hydrogen production example 2-1, the operating voltage of the fuel electrode and the air electrode and the generation rate of hydrogen generated at the fuel electrode were examined while changing the current flowing between the air electrode and the fuel electrode at the time of flowing air at a flow rate of 50 to 200 ml/min at a cell temperature of 70 ℃ and flowing a 1M methanol aqueous solution (fuel) at a flow rate of 5 ml/min at the fuel electrode.
Fig. 26 shows the relationship between the current density and the operating voltage derived in this test.
As the air flow rate becomes smaller, the operating voltage decreases, and a decrease in dischargeable limiting current density is observed.
In fig. 27, the results of fig. 26 are collated as the relationship between the operating voltage and the hydrogen generation rate.
From these results, it is found that the hydrogen generation rate tends to depend on the operating voltage, and hydrogen is generated at an operating voltage of 200 to 500 mV. It is also found that hydrogen is easily generated at an air flow rate of 50 to 100 ml/min. When the air flow rate is increased like 150, 200 ml/min, almost no hydrogen is generated.
Hydrogen production examples 2 to 4
Using a hydrogen production cell similar to that of hydrogen production example 2-1, the operating voltage of the fuel electrode and the air electrode and the generation rate of hydrogen generated at the fuel electrode were examined while changing the current flowing between the air electrode and the fuel electrode at the time of flowing air at a flow rate of 50 to 250 ml/min at a cell temperature of 90 ℃ and flowing a 1M methanol aqueous solution (fuel) at a flow rate of 5 ml/min at the fuel electrode.
Fig. 28 shows the relationship between the current density and the operating voltage derived in this test.
As the air flow rate becomes smaller, the operating voltage decreases, and a decrease in dischargeable limiting current density is observed.
In fig. 29, the results of fig. 28 are organized as the relationship between the operating voltage and the hydrogen generation rate.
From these results, it is found that the hydrogen generation rate tends to depend on the operating voltage, and hydrogen is generated at an operating voltage of 200 to 500 mV. It is also found that hydrogen is easily generated at an air flow rate of 50 to 100 ml/min. At 250 ml/min, almost no hydrogen was produced.
Next, the relationship between the current density and the operating voltage derived from the air flow rate of 50 ml/min at each temperature in the hydrogen production examples 2-1 to 2-4 is shown in FIG. 30, and the relationship between the operating voltage and the hydrogen generation rate is shown in FIG. 31.
From this, it is found that the hydrogen generation rate tends to depend on the temperature, and when the temperature is high, hydrogen is generated at a low operating voltage, and the amount of hydrogen generated increases.
Further, the relationship between the current density and the operating voltage derived from the air flow rate of 100 ml/min at each temperature in hydrogen production examples 2-1 to 2-4 is shown in FIG. 32, and the relationship between the operating voltage and the hydrogen generation rate is shown in FIG. 33.
From this, it is found that the hydrogen generation rate tends to depend on the temperature, and when the temperature is high, hydrogen is generated at a low operating voltage, and the amount of hydrogen generated increases. Further, when the air flow rate is increased to 100 ml/min, hydrogen is hardly generated at a low temperature such as 30 ℃ and 50 ℃.
Hydrogen production examples 2 to 5
Using a hydrogen production cell similar to that of hydrogen production example 2-1, the operating voltages of the fuel electrode and the air electrode and the generation rate of hydrogen generated at the fuel electrode were examined while changing the current flowing between the air electrode and the fuel electrode at a cell temperature of 50 ℃, while flowing air at a flow rate of 50 ml/min at the air electrode side and changing the fuel flow rate at the fuel electrode side to 1.5, 2.5, 5.0, 7.5, and 10.0 ml/min.
Fig. 34 shows the relationship between the current density and the operating voltage derived in this test.
It can be observed that the dischargeable limiting current density does not change much even if the fuel flow rate changes.
In fig. 35, the results of fig. 34 are organized as the relationship between the operating voltage and the hydrogen generation rate.
From this, it is found that the hydrogen generation rate under each condition depends on the operating voltage, and hydrogen is generated at 300 to 500 mV. Further, a large hydrogen generation rate was observed in the vicinity of 450 to 500 mV.
It can be seen that the hydrogen generation rate is less dependent on the fuel flow rate.
Hydrogen production examples 2 to 6
Using a hydrogen production cell similar to that of hydrogen production example 2-1, the operating voltage of the fuel electrode and the air electrode and the generation rate of hydrogen generated at the fuel electrode were examined while changing the current flowing between the air electrode and the fuel electrode at a cell temperature of 50 ℃ and flowing air at a flow rate of 50 ml/min on the air electrode side and a constant flow rate of 5 ml/min on the fuel electrode side and changing the fuel concentration to 0.5, 1, 2, and 3M.
Fig. 36 shows the relationship between the current density and the operating voltage derived in this test.
As the fuel concentration increases, the operating voltage decreases and a decrease in dischargeable limiting current density is observed.
Fig. 37 collates the results of fig. 36 as the relationship between the operating voltage and the hydrogen generation rate.
From this, it is found that the hydrogen generation rate under each condition depends on the operating voltage, and hydrogen is generated at 300 to 600 mV.
At a fuel concentration of 1M, hydrogen is most likely to be generated.
Hydrogen production examples 2 to 7
Using a hydrogen production cell similar to that of hydrogen production example 2-1 (except that the air electrode forms an oxidation electrode through which an oxidizing gas flows), the operating voltage of the fuel electrode and the oxidation electrode, and the rate of generation of hydrogen generated at the fuel electrode side were examined while changing the current flowing between the oxidation electrode and the fuel electrode at the time that 1M of fuel-concentration fuel was flowing at a constant flow rate of 5 ml/min at a cell temperature of 50 ℃ and the oxidizing gas was flowing at a flow rate of 14.0 ml/min at the oxidation electrode side and changing the oxygen concentration to 10, 21, 40, and 100%. Here, air was used as the gas having an oxygen concentration of 21%, a gas having an oxygen concentration of 10% was prepared by mixing nitrogen gas into air, and a gas having an oxygen concentration of 40% was prepared by mixing oxygen (oxygen concentration 100%) into air.
Fig. 38 shows the relationship between the current density and the operating voltage derived in this test.
When the oxygen concentration is low, the operating voltage decreases, and the dischargeable limiting current density decreases.
In fig. 39, the results of fig. 38 are collated as the relationship between the operating voltage and the hydrogen generation rate.
From this, it is found that the hydrogen generation rate under each condition depends on the operating voltage, and hydrogen is generated at 300 to 600 mV.
When the oxygen concentration is high, the hydrogen generation rate tends to increase.
Hydrogen production examples 2 to 8
Using the hydrogen production cell similar to that of hydrogenproduction example 2-1 (except that the air electrode forms an oxidation electrode for flowing liquid hydrogen peroxide), the hydrogen production cell was placed in a hot air circulation type electric furnace, the cell temperature was 30 ℃, 50 ℃, 70 ℃ and 90 ℃, 1M aqueous methanol solution (fuel) was flowed at a flow rate of 5 ml/min on the fuel electrode side, and 1M H was flowed at a flow rate of 2.6 to 5.5 ml/min on the oxidation electrode side2O2(hydrogen peroxide), the operating voltages of the fuel electrode and the oxidizing electrode and the rate of generation of hydrogen generated on the fuel electrode side were investigated while changing the current flowing between the oxidizing electrode and the fuel electrode. The flow rate of hydrogen peroxide was adjusted to approximately 500mV at each temperature.
Fig. 40 shows the relationship between the current density and the operating voltage derived in this test.
When the temperature is 70 to 90 ℃, the relationship between the decrease in the operating voltage and the increase in the current density is almost the same, and when the temperature is decreased to 30 ℃, the operating voltage is sharply decreased, and the dischargeable limiting current density is observed to decrease.
In fig. 41, the results of fig. 40 are organized as the relationship between the operating voltage and the hydrogen generation rate.
From this, it is found that the hydrogen generation rate tends to depend on the operating voltage, and hydrogen is generated at 300 to 500 mV. Further, hydrogen is most easily generated at a temperature of 90 ℃, and at a low temperature, it is observed that hydrogen is not generated unless the operating voltage is increased.
The point here is that in example 2 described above, the current is led out from the hydrogen production cell to the outside. In other words, in the hydrogen production cell of example 2, a part of the fuel was converted into hydrogen while discharging electric energy to the outside. Further, it is converted at an extremely low temperature of 30 to 90 ℃ and is considered to be an unprecedented new hydrogen production method and hydrogen production apparatus.
Example 3
The following shows an example of a case where hydrogen is produced by the hydrogen production method and the hydrogen production apparatus (charging conditions) according to the inventions of claims 4 and 14 of the present application.
Hydrogen production example 3-1
FIG. 42 shows a schematic diagram of a hydrogen production cell having a device for applying electric energy from the outside in example 3 (production examples 3-1 to 3-8).
The structure of the hydrogen production cell of hydrogen production example 1-1 was the same except that a device for applying electric energy from the outside was provided using a fuel electrode as a cathode and the above-described oxidizing electrode as an anode.
The hydrogen production cell was installed in a hot air circulation type electric furnace, and at a cell temperature (operating temperature) of 50 ℃, air was flowed at a flow rate of 10 to 80 ml/min on the air electrode side, and a 1M methanol aqueous solution (fuel) was flowed at a flow rate of 5 ml/min on the fuel electrode side, and at this time, the operating voltage of the fuel electrode and the air electrode, the amount of gas generated on the fuel electrode side, and the gas composition were investigated while changing the current flowing between the air electrode and the fuel electrode by using a direct current power supply from the outside. Here, the ratio of the chemical energy of the generated hydrogen to the input electric energy is set as the energy efficiency of the charging condition. The hydrogen concentration in the generated gas was analyzed by gas chromatography to determine the hydrogen generation rate.
The energy efficiency of the charging condition (hereinafter referred to as "energy efficiency") is calculated by the following calculation formula.
Calculating formula:
energy efficiency (%) ═ (H)2Combustion heat/applied electric energy) x 100
H formed within 1 minute2Heat of combustion (KJ) ═ H2The formation rate is ml/min/24.47/1000). times.286 KJ/mol [ HHV]
Electric energy (KJ) applied within 1 minute [ Voltage mV/1000 × Current A × 60sec]Wsec/1000
Although the description is given for the sake of caution, the object of the present invention is to obtain a hydrogen gas having a chemical energy equal to or higher than the input electric energy, regardless of the criterion of energy conservation determined by thermodynamics. In view of the whole, since a part of the organic fuel is oxidized, the input electric energy is 100% or less if it contains chemical energy consumed by the oxidation of the organic fuel. In the present invention, in order to clarify the difference in energy efficiency from the conventional electrolysis of water to produce hydrogen, the ratio of the chemical energy of the produced hydrogen to the input electric energy is expressed as energy efficiency.
In this test, the relationship between the applied current density and the hydrogen generation rate is shown in fig. 43.
When the current density is less than or equal to 40mA/cm2In the condition (2), there is a region where the hydrogen generation efficiency (the power generation efficiency of hydrogen generation) is 100% or more (a line where the hydrogen generation efficiency is 100% is shown by a broken line in fig. 43), and if the operation is performed in this region, hydrogen having the input power or more can be obtained.
In fig. 44, the results of fig. 43 are collated as the relationship between the operating voltage and the hydrogen generation rate.
From this, it is understood that the hydrogen generation rate (hydrogen generation amount) tends to depend on the operating voltage, and that hydrogen is generated at an operating voltage of 400mV or more, the hydrogen generation rate is substantially constant at 600mV or more, and the hydrogen generation rate is high (hydrogen is easily generated) when the air flow rate is small.
The relationship between the applied current density and the operating voltage is shown in fig. 45.
The regions identified in fig. 43 where the hydrogen generation efficiency is 100% or higher are all operating voltages of 600mV or lower in fig. 45.
Fig. 46 shows the relationship between the operating voltage and the energy efficiency.
It is found that even when the operating voltage is around 1000mV, the energy efficiency is 100% or more, and particularly when the operating voltage is 600mV or less and the air flow rate is 30 to 50 ml/min, the energy efficiency is high.
Then, at a high energy efficiency (1050%), a temperature of 50 ℃, a fuel flow rate of 5 ml/min, an air flow rate of 50 ml/min, and a current density of 4.8mA/cm2Gas was generated under the conditions of (1), and the hydrogen concentration in the gas was measured by gas chromatography. As a result, it was found that the produced gas contained about 86% of hydrogen and the hydrogen generation rate was7.8 ml/min. In addition, no CO was detected.
Hydrogen production example 3-2
In the case of a hydrogen production cell using the same hydrogen production cell as in hydrogen production example 3-1, the operating voltage of the fuel electrode and the air electrode, the rate of generation of hydrogen generated in the fuel electrode side, and the energy efficiency were examined while changing the current flowing between the air electrode and the fuel electrode by using a direct current power supply from the outside at a cell temperature of 30 ℃ and flowing air at a flow rate of 10 to 70 ml/min and 1M methanol aqueous solution (fuel) at a flow rate of 5 ml/min in the fuel electrode side.
In this test, the relationship between the applied current density and the hydrogen generation rate is shown in fig. 47, and the relationship between the operating voltage and the hydrogen generation rate is shown in fig. 48.
From this, it is found that the hydrogen generation rate (hydrogen generation amount) tends to depend on the operating voltage, and hydrogen gas is generated at an operating voltage of 400mV or more, and hydrogen is easily generated at a small air flow rate. When the air flow is 10 ml/min, the hydrogen generation speed is basically constant when the air flow is more than or equal to 600 mV; when the air flow rate is 30 ml/min, the tendency of increase is exhibited at 800mV or more; in the case where the air flow rate is higher than that, hydrogen is not generated without increasing the operating voltage.
Fig. 49 shows the relationship between the operating voltage and the energy efficiency.
It is found that the energy efficiency is not less than 100% even when the operating voltage is around 1000mV, and particularly when the operating voltage is not more than 600mV and the air flow rate is 30 ml/min, the energy efficiency is high.
Hydrogen production examples 3 to 3
Tests were carried out under the same conditions as in hydrogen production example 3-2 except that the cell temperature was set to 70 ℃, and the operating voltages of the fuel electrode and the air electrode, the generation rate of hydrogen generated at the fuel electrode side, and the energy efficiency were examined.
In this test, the relationship between the applied current density and the hydrogen generation rate is shown in FIG. 50, and the relationship between the operating voltage and the hydrogen generation rate is shown in FIG. 51.
From this, it is found that the hydrogen generation rate tends to depend on the operating voltage, and hydrogen is generated at an operating voltage of 400mV or more, and hydrogen is easily generated when the air flow rate is small. When the air flow is 10 ml/min, the hydrogen generation speed is basically constant when the air flow is more than or equal to 600 mV; when the air flow rate is 30 ml/min, the tendency of increase is exhibited at 800mV or more; in the case where the air flow rate is higher than that, hydrogen is not generated without increasing the operating voltage.
Fig. 52 shows a relationship between operating voltage and energy efficiency.
It is found that even when the operating voltage is around 1000mV, the energy efficiency is 100% or more, and particularly when the operating voltage is 600mV or less and the air flow rate is 10 to 30 ml/min, the energy efficiency is high.
Hydrogen production examples 3 to 4
Using a hydrogen production cell similar to that of hydrogen production example 3-1, the operating voltage of the fuel electrode and the air electrode, the rate of generation of hydrogen generated at the fuelelectrode side, and the energy efficiency were examined while changing the current flowing between the air electrode and the fuel electrode by using a direct current power supply from the outside at a cell temperature of 90 ℃, while flowing air at a flow rate of 10 to 200 ml/min at the air electrode side and flowing a 1M methanol aqueous solution (fuel) at a flow rate of 5 ml/min at the fuel electrode side.
In this test, the relationship between the applied current density and the hydrogen generation rate is shown in FIG. 53, and the relationship between the operating voltage and the hydrogen generation rate is shown in FIG. 54.
From this, it is found that the hydrogen generation rate tends to depend on the operating voltage, hydrogen is generated at an operating voltage of 300mV or more, hydrogen is easily generated at a small air flow rate, the hydrogen generation rate is substantially constant at an air flow rate of 10 ml/min or 500mV or more, the hydrogen generation rate tends to increase at an air flow rate of 50 to 100 ml/min or 800mV or more, and hydrogen is not generated at an air flow rate of 200 ml/min or 800mV or less.
Fig. 55 shows the relationship between the operating voltage and the energy efficiency.
It is found that even when the operating voltage is around 1000mV, the energy efficiency is 100% or more, and particularly when the operating voltage is 500mV or less and the air flow rate is 50 ml/min, the energy efficiency is high.
Next, the relationship between the current density applied at an air flow rate of 50 ml/min and the hydrogen generation rate at each temperature in the hydrogen production examples 3-1 to 3-4 is shown in FIG. 56, and the relationship between the operating voltage and the hydrogen generation rate is shown in FIG. 57.
From this, it is found that the hydrogen generation rate tends to depend on the temperature, and that when the operating temperature is high, hydrogen is generated at a low operating voltage, and the hydrogen generation rate is also high.
Fig. 58 shows the relationship between the operating voltage and the energy efficiency.
It is found that even when the operating voltage is around 1000mV, the energy efficiency is 100% or more, and particularly when the operating voltage is 600mV or less, the energy efficiency is high.
Hydrogen production examples 3 to 5
Using a hydrogen production cell similar to that of hydrogen production example 3-1, the operating voltage of the fuel electrode and the air electrode, the rate of generation of hydrogen generated at the fuel electrode side, and the energy efficiency were investigated while changing the current flowing between the air electrode and the fuel electrode from an external direct current power supply under the condition that the air was flowed at the air electrode side at a flow rate of 50 ml/min and the flow rate of the fuel electrode side was changed at a flow rate of 1.5, 2.5, 5.0, 7.5, and 10.0 ml/min at a cell temperature of 50 ℃.
In this test, the relationship between the applied current density and the hydrogen generation rate is shown in fig. 59, and the relationship between the operating voltage and the hydrogen generation rate is shown in fig. 60.
From this, it is found that the hydrogen generation rate tends to depend on the operating voltage, and that hydrogen is generated at an operating voltage of 400mV or more, hydrogen is easily generated at a large fuel flow rate, and the hydrogen generation rate tends to increase at 800mV or more for any fuel flow rate.
Fig. 61 shows the relationship between the operating voltage and the energy efficiency.
It is understood that, in the case of any fuel flow rate, even if the operating voltage is around 1000mV, the energy efficiency is 100% or more, and particularly, when the operating voltage is 600mV or less, the energy efficiency is high.
Hydrogen production examples 3 to 6
Using a hydrogen production cell similar to that of hydrogen production example 3-1, the operating voltages of the fuel electrode and the air electrode, the rate of generation of hydrogen generated at the fuel electrode side, and the energy efficiency were investigated while changing the current flowing between the air electrode and the fuel electrode from the outside using a direct current power supply under the condition that the air was flowed at a flow rate of 50 ml/min at the air electrode side and the fuel was flowed at a constant flow rate of 5 ml/min at the fuel electrode side at a cell temperature of 50 ℃.
In this test, the relationship between the applied current density and the hydrogen generation rate is shown in fig. 62, and the relationship between the operating voltage and the hydrogen generation rate is shown in fig. 63.
It is understood from the above that the concentration of the fuel is 0.02A/cm or more2The applied current density is substantially proportional to the hydrogen generation rate.
The hydrogen generation rate tends to depend on the operating voltage, and hydrogen is generated at an operating voltage of 400mV or higher, while hydrogen is likely to be generated even at a low operating voltage when the fuel concentration is high. When the fuel concentration is 2M or 3M, the hydrogen generation rate is increased sharply at 400-500 mV; when the fuel concentration is 1M, the hydrogen generation speed is basically constant at 400-800 mV, and the hydrogen generation speed is increased at morethan or equal to 800 mV; in the case where the fuel concentration is lower than that, hydrogen is not generated without increasing the operating voltage.
Fig. 64 shows a relationship between operating voltage and energy efficiency.
It is understood that, in addition to the case where the fuel concentration is 0.5M, even when the operating voltage is around 1000mV, the energy efficiency is 100% or more, and particularly, when the operating voltage is 600mV or less, the energy efficiency is high when the fuel concentration is 1, 2, or 3M. In addition, when the fuel concentration is 0.5M, hydrogen is not generated in the low voltage region, and the energy efficiency is completely different from that in the case of other conditions.
Hydrogen production examples 3 to 7
Using a hydrogen production cell similar to that of hydrogen production example 3-1 (except that the air electrode forms an oxidation electrode through which an oxidizing gas flows), the operating voltages of the fuel electrode and the oxidation electrode, the rate of generation of hydrogen generated at the fuel electrode side, and the energy efficiency were examined while changing the current flowing between the oxidation electrode and the fuel electrode from the outside using a direct current power supply under conditions in which the cell temperature was 50 ℃, the constant flow rate of fuel at the fuel electrode side concentration of 1M was 5 ml/min, and the flow rate of the oxidizing gas was 14.0 ml/min, and the oxygen concentrations were 10, 21, 40, and 100%. Here, air was used as the gas having an oxygen concentration of 21%, a gas having an oxygen concentration of 10% was prepared by mixing nitrogen gas into air, and a gas having an oxygen concentration of 40% was prepared by mixing oxygen (oxygen concentration 100%) into air.
In this test, the relationship between the applied current density and the hydrogen generation rate is shown in fig. 65, and the relationship between the operating voltage and the hydrogen generation rate is shown in fig. 66.
It is understood from the above that the concentration of oxygen is 0.03A/cm or more2The applied current density is substantially proportional to the hydrogen generation rate.
The hydrogen generation rate tends to depend on the operating voltage, and hydrogen is generated at an operating voltage of 400mV or higher, while hydrogen is easily generated even at a low operating voltage when the oxygen concentration is high, and the hydrogen generation rate is substantially constant at 400 to 800mV and tends to increase at 800mV or higher.
Fig. 67 shows the relationship between the operating voltage and the energy efficiency.
It is found that the energy efficiency is 100% or more even when the applied voltage is around 1000mV, and particularly that the energy efficiency is high when the applied voltage is 600mV or less and the oxygen concentration is high.
Hydrogen production examples 3 to 8
Using the hydrogen production cell similar to that of hydrogen production example 3-1 (except that the air electrode forms an oxidation electrode for flowing liquid hydrogen peroxide), the hydrogen production cell was placed in a hot air circulation type electric furnace at a cell temperature of 30 ℃, 50 ℃, 70 ℃ and 90 ℃, with a methanol aqueous solution (fuel) having a flow rate of 5 ml/min and a flow concentration of 1M on the fuel electrode side, and with a flow rate of 2.6 to 5.5 ml/min and H having a flow rate of 1M on the oxidation electrode side2O2(peroxy)Hydrogen generation), the operating voltages of the fuel electrode and the oxidizing electrode, the generation rate of hydrogen generated on the fuel electrode side, and the energy efficiency were investigated while changing the current flowing between the oxidizing electrode and the fuel electrode by using a dc power supply from the outside.
The hydrogen peroxide flow was adjusted to a switching voltage of essentially 500mV at each temperature.
In this test, the relationship between the applied current density and the hydrogen generation rate is shown in fig. 68, and the relationship between the operating voltage and the hydrogen generation rate is shown in fig. 69.
From this, it is found that the hydrogen generation rate tends to depend on the operating voltage, hydrogen is generated at an operating voltage of 500mV or more, hydrogen is increased at an operating voltage of 800mV or more, and hydrogen is easily generated at a high operating temperature.
Fig. 70 shows a relationship between operating voltage and energy efficiency.
It is found that the energy efficiency is 100% or more even when the operating voltage is around 1000mV, and particularly, the energy efficiency is high when the operating voltage is 800mV or less and the temperature is 90 ℃.
Here, it is important that the above example 3 is to obtain hydrogen at a current applied from the outside to the hydrogen production cell or more. In other words, with the hydrogen producing cell of example 3, hydrogen having an energy equal to or greater than the applied electric energy was produced. Further, it is converted at an extremely low temperature of 30 to 90 ℃ and is considered to be an unprecedented new hydrogen production method and hydrogen production apparatus.
Possibility of industrial utilization
As described above, the hydrogen production method and the hydrogen production apparatus of the present invention can produce a hydrogen-containing gas by decomposing a fuel containing an organic substance at 100 ℃ or lower, and can easily supply hydrogen to a fuel cell, a hydrogen storage container, and the like, and therefore are extremely effective for use in electric vehicles, submarines, hydrogen supply systems, packaged fuel cell power generation apparatuses, and the like.

Claims (57)

1. A hydrogen production method for producing a hydrogen-containing gas by decomposing a fuel containing an organic substance, characterized in that a fuel electrode is provided on one surface of a separator, the fuel electrode is supplied with a fuel containing the organic substance and water, an oxidizing electrode is provided on the other surface of the separator, an oxidizing agent is supplied to the oxidizing electrode, the fuel containing the organic substance is decomposed, and the hydrogen-containing gas is generated from the fuel electrode side.
2. The hydrogen production method according to claim 1, wherein the hydrogen-containing gas is generated under open circuit conditions without drawing electric energy from a hydrogen production cell constituting the hydrogen production apparatus to the outside or supplying electric energy to the hydrogen production cell from the outside.
3. The method for producing hydrogen according to claim 1, wherein the fuel electrode is a negative electrode, the oxidizing electrode is a positive electrode, and the fuel containing organic matter is decomposed while electric energy is externally discharged, thereby generating a hydrogen-containing gas from a fuel electrode side.
4. The method for producing hydrogen according to claim 1, wherein the fuel electrode is used as a cathode, the oxidizing electrode is used as an anode, and the fuel containing the organic matter is decomposed while applying electric energy from the outside to generate a hydrogen-containing gas from the fuel electrode side.
5. The method for producing hydrogen according to any one of claims 1 to 4, wherein the organic substance is an alcohol.
6. The method for producing hydrogen according to claim 5, wherein the alcohol is methanol.
7. The method for producing hydrogen according to any one of claims 1 to 4, wherein the oxidizing agent is an oxygen-containing gas or oxygen gas.
8. The hydrogen production method according to claim 5, wherein the oxidizing agent is an oxygen-containing gas or oxygen gas.
9. The method for producing hydrogen according to any one of claims 1 to 4, wherein the oxidizing agent is a liquid containing hydrogen peroxide.
10. The method for producing hydrogen according to claim 5, wherein the oxidizing agent is a liquid containing hydrogen peroxide.
11. A hydrogen production apparatus for producing a hydrogen-containing gas by decomposing a fuel containing an organic substance, the hydrogen production apparatus comprising a membrane, a fuel electrode provided on one surface of the membrane, a means for supplying the fuel containing the organic substance and water to the fuel electrode, an oxidizing electrode provided on the other surface of the membrane, a means for supplying an oxidizing agent to the oxidizing electrode, and a means for generating the hydrogen-containing gas from the fuel electrode side and extracting the hydrogen-containing gas.
12. The hydrogen production apparatus according to claim 11, which is in an open state without a device for externally leading electric energy from a hydrogen production cell constituting the hydrogen production apparatus and a device for externally supplying electric energy to the hydrogen production cell.
13. The hydrogen generator according to claim 11, wherein the fuel electrode is a negative electrode, and the oxidizing electrode is a positive electrode, and an electric energy is externally discharged.
14. The hydrogen generator according to claim 11, wherein the fuel electrode is a cathode, and the oxidizing electrode is an anode, and the electric energy is applied from outside.
15. The hydrogen generator according to claim 11, wherein a voltage between the fuel electrode and the oxidizing electrode is 200 to 1000 mV.
16. The hydrogen generator according to claim 12, wherein a voltage between the fuel electrode and the oxidizing electrode is 300 to 800 mV.
17. The hydrogen generator according to claim 13, wherein a voltage between the fuel electrode and the oxidizing electrode is 200 to 600 mV.
18. The hydrogen generator according to claim 13, wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount of the hydrogen-containing gas generated is adjusted by adjusting the derived electric energy.
19. The hydrogen generator according to claim 14, wherein a voltage between the fuel electrode and the oxidizing electrode is 300 to 1000 mV.
20. The hydrogen production apparatus according to claim 14, wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount of the hydrogen-containing gas generated is adjusted by adjusting the applied electric energy.
21. The hydrogen generator according to any one of claims 11 to 20, wherein the amount of the hydrogen-containing gas generated is adjusted by adjusting a voltage between the fuel electrode and the oxidizing electrode.
22. The hydrogen generator according to any one of claims 11 to 20, wherein a voltage between the fuel electrode and the oxidizing electrode and/or a generation amount of the hydrogen-containing gas are adjusted by adjusting a supply amount of the oxidizing agent.
23. The hydrogen production apparatus according to any one of claims 11 to 20, wherein a voltage between the fuel electrode and the oxidizing electrode and/or a generation amount of the hydrogen-containing gas are adjusted by adjusting a concentration of the oxidizing agent.
24. The hydrogen generator according to claim 22, wherein a voltage between the fuel electrode and the oxidizing electrode and/or a generation amount of the hydrogen-containing gas are adjusted by adjusting a concentration of the oxidizing agent.
25. The hydrogen generator according to any one of claims 11 to 20, wherein a voltage between the fuel electrode and the oxidizing electrode and/or a generation amount of the hydrogen-containing gas are adjusted by adjusting a supply amount of the fuel containing the organic matter and water.
26. The hydrogen generator according to claim 22, wherein the voltage between the fuel electrode and the oxidizing electrode and/or the amount of the hydrogen-containing gas generated is adjusted by adjusting the amount of the fuel containing the organic substance and water supplied.
27. The hydrogen generator according to claim 23, wherein a voltage between the fuel electrode and the oxidizing electrode and/or a generation amount of the hydrogen-containing gas are adjusted by adjusting a supply amount of the fuel containing the organic matter and water.
28. The hydrogen generator according to any one of claims 11 to 20, wherein a voltage between the fuel electrode and the oxidizing electrode and/or a generation amount of the hydrogen-containing gas are adjusted by adjusting a concentration of the fuel containing an organic substance and water.
29. The hydrogen generator according to claim 22, wherein a voltage between the fuel electrode and the oxidizing electrode and/or a generation amount of the hydrogen-containing gas are adjusted by adjusting a concentration of the fuel containing the organic matter and water.
30. The hydrogen generator according to claim 23, wherein a voltage between the fuel electrode and the oxidizing electrode and/or a generation amount of the hydrogen-containing gas are adjusted by adjusting a concentration of the fuel containing the organic matter and water.
31. The hydrogen generator according to claim 25, wherein a voltage between the fuel electrode and the oxidizing electrode and/or a generation amount of the hydrogen-containing gas are adjusted by adjusting a concentration of the fuel containing the organic matter and water.
32. The hydrogen production apparatus according to any one of claims 11 to 20, wherein the operating temperature is 100 ℃ or lower.
33. The hydrogen production apparatus according to claim 32, wherein the operating temperature is 30 to 90 ℃.
34. The hydrogen production apparatus according to claim 21, wherein the operating temperature is 100 ℃ or lower.
35. The hydrogen production apparatus according to claim 22, wherein the operating temperature is 100 ℃ or lower.
36. The hydrogen production apparatus according to claim 23, wherein the operating temperature is 100 ℃ or lower.
37. The hydrogen production apparatus according to claim 25, wherein the operating temperature is 100 ℃ or lower.
38. The hydrogen production apparatus according to claim 28, wherein the operating temperature is 100 ℃ or lower.
39. The hydrogen production apparatus according to any one of claims 11 to 20, wherein the separator is a proton conductive solid electrolyte membrane.
40. The hydrogen production apparatus according to claim 39, wherein the proton conductive solid electrolyte membrane is a perfluorocarbon sulfonic acid-based solid electrolyte membrane.
41. The hydrogen production apparatus according to claim 32, wherein the separator is a proton conductive solid electrolyte membrane.
42. The hydrogen production apparatus according to any one of claims 33 to 38, wherein the separator is a proton conductive solid electrolyte membrane.
43. The hydrogen generator according to any one of claims 11 to 20, wherein the catalyst of the fuel electrode is a catalyst in which a Pt — Ru alloy is supported on carbon powder.
44. The hydrogen generator according to claim 32, wherein the catalyst of the fuel electrode is a catalyst in which a Pt — Ru alloy is supported on carbon powder.
45. The hydrogen generator according to any one of claims 33 to 38, wherein the catalyst of the fuel electrode is a catalyst in which a Pt — Ru alloy is supported on carbon powder.
46. The hydrogen generator according to claim 39, wherein the catalyst of the fuel electrode is a catalyst in which a Pt-Ru alloy is supported on carbon powder.
47. The hydrogen production apparatus according to any one of claims 11 to 20, wherein the catalyst of the oxidation electrode is a catalyst in which Pt is supported on carbon powder.
48. The hydrogen generator according to claim 32, wherein the catalyst of the oxidation electrode is a catalyst in which Pt is supported on carbon powder.
49. The hydrogen production apparatus according to any one of claims 33 to 38, wherein the catalyst of the oxidation electrode is a catalyst in which Pt is supported on carbon powder.
50. The hydrogen generator according to claim 39, wherein the catalyst of the oxidation electrode is a catalyst in which Pt is supported on carbon powder.
51. The hydrogen generator according to claim 43, wherein the catalyst of the oxidation electrode is a catalyst in which Pt is supported on carbon powder.
52. The hydrogen production apparatus according to any one of claims 11 to 20, wherein a circulation device for the fuel containing an organic substance and water is provided.
53. The hydrogen production apparatus according to claim 32, wherein a circulation device for the fuel containing the organic matter and water is provided.
54. The hydrogen production apparatus according to any one of claims 33 to 38, wherein a circulation device for the fuel containing an organic substance and water is provided.
55. The hydrogen production apparatus according to any one of claims 11 to 20, wherein a carbon dioxide absorbing unit is provided for absorbing carbon dioxide contained in the hydrogen-containing gas.
56. The hydrogen production apparatus according to claim 32, wherein a carbon dioxide absorption unit is provided for absorbing carbon dioxide contained in the hydrogen-containing gas.
57. The hydrogen production apparatus according to any one of claims 33 to 38, wherein a carbon dioxide absorption unit is provided for absorbing carbon dioxide contained in the hydrogen-containing gas.
CNB2004800410161A 2003-12-26 2004-12-21 Method for producing hydrogen and hydrogen-producing apparatus used therefor Expired - Fee Related CN100526212C (en)

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CN103757656A (en) * 2014-01-20 2014-04-30 中国工程物理研究院化工材料研究所 Photoelectrochemical hydrogen producing device combining primary battery and photoelectrochemical battery
CN108093633A (en) * 2015-04-16 2018-05-29 沙特阿拉伯石油公司 The method of coprocessing carbon dioxide and hydrogen sulfide

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Publication number Priority date Publication date Assignee Title
JP3328993B2 (en) * 1993-05-10 2002-09-30 住友電気工業株式会社 Hydrogen generation method

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Publication number Priority date Publication date Assignee Title
CN103757656A (en) * 2014-01-20 2014-04-30 中国工程物理研究院化工材料研究所 Photoelectrochemical hydrogen producing device combining primary battery and photoelectrochemical battery
CN103757656B (en) * 2014-01-20 2016-02-03 中国工程物理研究院化工材料研究所 In conjunction with the PhotoelectrochemicalSystem System for Hydrogen Production device of galvanic cell and photoelectrochemical cell
CN108093633A (en) * 2015-04-16 2018-05-29 沙特阿拉伯石油公司 The method of coprocessing carbon dioxide and hydrogen sulfide
CN108093633B (en) * 2015-04-16 2021-07-27 沙特阿拉伯石油公司 Method for co-processing carbon dioxide and hydrogen sulfide

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