CN100558630C - Hydrogen supply system - Google Patents

Abstract

The invention provides hydrogen supply system from hydrogen to hydrogen-storing device that can easily supply with, its use can be made hydrogen-containing gas at low temperatures, and does not need the hydrogen producing apparatus of a large amount of electric energy.Hydrogen supply system, at least has the hydrogen producing apparatus (10) that the hydrogen storage vessel that for example carries on the fuel cell car to hydrogen-storing device is supplied with the hydrogen supplier of hydrogen and made the hydrogen-containing gas that is used to supply with described hydrogen supplier, this hydrogen supply system is characterised in that, hydrogen producing apparatus is to decompose to contain the device that organic fuel is made hydrogen-containing gas, this hydrogen producing apparatus has: barrier film (11), the fuel electrodes (12) that on a membranous face, is provided with, supply with the device (16) of the fuel that contains organism and water to fuel electrodes (12), the oxidation utmost point (14) that on the another side of barrier film (11), is provided with, to the device (17) of the oxidation utmost point (14) supply oxygenant, the device of deriving by fuel electrodes side generation hydrogen-containing gas.

Description

Hydrogen supply system

technical field

The present invention relates to a hydrogen supply system for supplying hydrogen to a hydrogen storage device such as a hydrogen storage container mounted on a fuel cell vehicle or a hydrogen storage tank for supplying hydrogen to a fuel cell vehicle or the like.

Background technique

Currently, the development of fuel cell vehicles is being actively developed as a countermeasure against environmental problems, resource problems, and the like. As a fuel cell vehicle, a fuel cell vehicle equipped with a container for storing hydrogen in the form of hydrogen gas or in the form of a hydrogen storage alloy is being developed, but the maintenance of hydrogen supply infrastructure is a huge issue in its popularization. That is, there is a problem of how to maintain a wide range of hydrogen supply infrastructure for free-running fuel cell vehicles. Among them, steam reforming of city gas and even liquid fuels (desulfurized naphtha, gasoline, kerosene, diesel, methanol, etc.) Hydrogen supply systems such as hydrogen storage tanks mounted on fuel cell vehicles have been developed most due to the advantage of making maximum use of existing infrastructure such as city gas pipeline networks and fuel supply stations (for example, refer to Patent Documents 1 to 4) .

However, the above-mentioned hydrogen supply system has problems such as high manufacturing cost of the reformer, large size of the reformer, complicated maintenance and operation of the plant, and high technology required.

Patent Document 1: JP-A-2002-315111

Patent Document 2: JP-A-2002-337999

Patent Document 3: JP-A-2003-118548

Patent Document 4: JP-A-2004-79262

In addition, as a reformer, the reformer for methanol, which has the lowest reforming temperature among the above-mentioned fuels, is developing the fastest. Currently, the reforming method uses steam reforming, partial oxidation reforming, and a combination of these two methods. These three methods of reforming are used in combination (refer to Non-Patent Document 1), but even if any reforming method is used, in order to produce hydrogen-containing gas, reforming must be carried out at a high temperature above 200°C, and there are problems with reforming Catalyst poisoning, removal of CO contained in reformed gas (hydrogen-containing gas), partial oxidation reforming or combined use of reformed gas mixed with nitrogen in the air, etc.

Non-Patent Document 1: "Development and Application of Solid Polymer Fuel Cells", pages 141 to 166, May 28, 1999, published by the Technology Information Association Co., Ltd.

On the other hand, as a method of reforming fuel containing organic substances as described above, electrolyzing water to produce hydrogen, storing such hydrogen in a hydrogen storage tank, and supplying such hydrogen to a storage tank mounted on a fuel cell vehicle is being developed. A system such as a hydrogen container (for example, refer to Patent Documents 5 and 6).

According to such a system, there is a problem that a large amount of electric power is required although high temperatures such as reforming fuel containing organic matter are not required.

Patent Document 5: JP-A-2002-161998

Patent Document 6: JP-A-2002-363779

In addition, methods for generating hydrogen by an electrochemical reaction (see Patent Documents 7 and 9) and inventions of fuel cells using hydrogen generated by an electrochemical method are known (see Patent Documents 8 to 10).

Patent Document 7: Patent No. 3328993

Patent Document 8: Patent No. 3360349

Patent Document 9: US Patent No. 6,299,744, US Patent No. 6,368,492, US Patent No. 6,432,284, US Patent No. 6,533,919, US Patent Publication No. 2003/0226763

Patent Document 10: JP-A-2001-297779

In the above-mentioned Patent Document 7, the following invention is described (claim 1): "The hydrogen generation method is characterized in that a pair of electrodes are provided on the two faces of the cation exchange membrane facing each other, and a fuel containing at least methanol and water is brought into contact. An electrode containing a catalyst provided on one surface, electrons are extracted from the pair of electrodes by applying a voltage to the pair of electrodes, a reaction of generating hydrogen ions from the methanol and water proceeds on the electrodes, and the The hydrogen ions generated are converted into hydrogen molecules by donating electrons to the electrodes on the other side of the pair of faces of the cation exchange membrane. In addition, the following content is also disclosed (paragraphs [0033]-[0038]): supplying methanol as a fuel to the fuel electrode while supplying water or water vapor, connecting an external circuit, applying a voltage to extract electrons from the fuel electrode, As a result, the reaction of CH ₃ OH+2H ₂ O→CO ₂ +6e ^- +6H ⁺ proceeds on the fuel electrode, and the resulting hydrogen ions pass through the cation exchange membrane and pass through 6H ⁺ +6e ^- on the opposite electrode side. → 3H ₂ to selectively generate hydrogen. Furthermore, Patent Document 8 describes an invention of a fuel cell utilizing hydrogen generated by such a method (paragraphs [0052] to [0056]).

According to the inventions described in Patent Documents 7 and 8, hydrogen can be generated at a low temperature (paragraph [0042] of Patent Document 7 and paragraph [0080] of Patent Document 8), but it is necessary to apply a voltage in order to generate hydrogen. The generation is on the opposite electrode side of the fuel electrode (fuel electrode), and the oxidizing agent is not supplied to the opposite electrode, so it is significantly different from the hydrogen production device used in the hydrogen supply system of the present invention.

The invention described in the above-mentioned Patent Document 9 is also the same as the inventions described in the above-mentioned Patent Documents 7 and 8, in that protons generated at the anode 112 serving as the fuel electrode permeate the diaphragm 110 and hydrogen is generated at the cathode 114 serving as the counter electrode. , which uses the fuel pole anode and the counter electrode as the cathode to apply voltage from the DC power supply 120 to electrolyze organic fuels such as methanol, and the generation of hydrogen is on the counter electrode side of the fuel pole, and no oxidant is supplied to the counter electrode. The hydrogen production device used on the invented hydrogen supply system is significantly different.

The above-mentioned Patent Document 10 describes that a hydrogen generating electrode that generates hydrogen is provided in a fuel cell system (claim 1), but the content of the description is that "a liquid fuel containing alcohol and water is supplied to the porous electrode (fuel electrode) 1, and vice versa. When the gas diffusion electrode (oxidant electrode) 2 on the side is supplied with air, and the load is maintained between the terminal of the porous electrode 1 and the terminal of the gas diffusion electrode 2, the gas diffusion electrode 2, which is the positive electrode of the MEA2 having the function of a normal fuel cell, An electrical connection can be formed by applying a positive potential to the porous electrode 1 by a load. As a result, the alcohol reacts with water to generate carbon dioxide and hydrogen ions, which generate hydrogen via the electrolyte layer 5 on the gas diffusion electrode 6 in the center. On the gas diffusion electrode 6, an electrode reaction occurs at the interface with another electrolyte layer 7, and hydrogen ions are formed again and move in the electrolyte layer 7 to reach the gas diffusion electrode 2. On the gas diffusion electrode 2, it reacts with oxygen in the air to form Generate water" (paragraph 0007), so Patent Document 10 uses the electric energy generated by the fuel cell to generate hydrogen at the hydrogen generating electrode (gas diffusion electrode 6), and then supplies it to the fuel cell. In addition, the generation of hydrogen is at the fuel electrode. On the counter electrode side, it is the same as Patent Documents 7 to 9 mentioned above.

In addition, it is known that there is a reaction device having a diaphragm in which an anode (electrode A) and a cathode (electrode B) are formed with a proton-conducting membrane (ion conductor) interposed therebetween, and alcohol (methanol) is oxidized while deriving electrical energy by applying or not applying voltage. ) method inventions (refer to Patent Documents 11 and 12), but they are all about the process of using an electrochemical cell to oxidize alcohols (products are carbonic acid diester, formalin, methyl formate, dimethoxymethane, etc. ), not a process in which hydrogen is produced as a reducing product from alcohol.

Patent Document 11: JP-A-6-73582 (Claims 1 to 3, paragraph [0050])

Patent Document 12: JP-A-6-73583 (Claims 1, 8, paragraphs [0006], [0019])

Contents of the invention

The object of the present invention is to solve the above problems and provide a hydrogen supply system that can easily supply hydrogen storage devices such as hydrogen storage containers mounted on fuel cell vehicles, hydrogen storage tanks for supplying hydrogen on fuel cell vehicles, etc. Hydrogen, which uses a hydrogen production device that can produce hydrogen-containing gas at low temperature and does not require large electric power.

In order to solve the above-mentioned problems, the present invention adopts the following means.

(1) A hydrogen supply system comprising at least a hydrogen supply device for supplying hydrogen to a hydrogen storage device and a hydrogen production device for producing a hydrogen-containing gas for supply to the hydrogen supply device, wherein the hydrogen production device is a hydrogen production device that decomposes A hydrogen production device for producing hydrogen-containing gas from fuel containing organic matter, comprising a diaphragm, a fuel electrode provided on one surface of the diaphragm, a device for supplying fuel containing organic matter and water to the fuel electrode, and a fuel electrode provided on the diaphragm. An oxide electrode on the other side of the fuel electrode, a device for supplying an oxidant to the oxide electrode, and a device for deriving hydrogen-containing gas generated from the fuel electrode side.

(2) The hydrogen supply system according to (1), wherein the hydrogen storage device is a hydrogen storage container mounted on a fuel cell vehicle.

(3) The hydrogen supply system described in (1) or (2), wherein the hydrogen production device does not have a device for exporting electric energy to the outside from the hydrogen production cell constituting the hydrogen production device and a device for supplying electric energy to the outside from the outside. The open-circuit state of the device for applying electrical energy to the hydrogen production cell.

(4) The hydrogen supply system according to (1) or (2), wherein the hydrogen production device has a device for exporting electric energy to the outside by using the fuel electrode as a negative electrode and the oxidizing electrode as a positive electrode.

(5) The hydrogen supply system according to (1) or (2), wherein the hydrogen production device has means for applying electric energy from the outside by using the fuel electrode as a cathode and the oxide electrode as an anode.

(6) The hydrogen supply system described in (1) or (2), wherein two or more hydrogen production devices selected from the following hydrogen production devices are used in combination: An open-circuit hydrogen production device in which the battery derives electrical energy from the outside and the device that applies electrical energy to the hydrogen production battery from the outside; it has a device that uses the fuel pole as the negative pole and the oxidation pole as the positive pole to export electrical energy to the outside A hydrogen production device; and a hydrogen production device having a device for externally applying electrical energy by using the fuel as a cathode and using the oxide as an anode.

(7) The hydrogen supply system according to (1) or (2), wherein in the hydrogen production device, the voltage between the fuel electrode and the oxidation electrode is 200 to 1000 mV.

(8) The hydrogen supply system according to (3), wherein in the hydrogen production device, the voltage between the fuel electrode and the oxide electrode is 300 to 800 mV.

(9) The hydrogen supply system according to (4), wherein in the hydrogen production device, the voltage between the fuel electrode and the oxide electrode is 200 to 600 mV.

(10) The hydrogen supply system described in (4) or (9), characterized in that, in the hydrogen production device, by adjusting the derived electric energy, the gap between the fuel electrode and the oxidation electrode is adjusted. The voltage and/or the generation amount of the hydrogen-containing gas.

(11) The hydrogen supply system according to (5), wherein in the hydrogen production device, the voltage between the fuel electrode and the oxidation electrode is 300 to 1000 mV.

(12) The hydrogen supply system according to (5) or (11), wherein, in the hydrogen production device, the distance between the fuel electrode and the oxidation electrode is adjusted by adjusting the applied electric energy. The voltage and/or the generation amount of the hydrogen-containing gas.

(13) The hydrogen supply system according to any one of (1) to (12), wherein in the hydrogen production device, by adjusting the voltage between the fuel electrode and the oxidation electrode To adjust the generation amount of the hydrogen-containing gas.

(14) The hydrogen supply system according to any one of (1) to (13), wherein in the hydrogen production device, the fuel electrode and the fuel electrode are adjusted by adjusting the supply amount of the oxidizing agent. The voltage between the oxide electrodes and/or the generation amount of the hydrogen-containing gas.

(15) The hydrogen supply system according to any one of (1) to (14), wherein in the hydrogen production device, the fuel electrode and the The voltage between the oxide electrodes and/or the generation amount of the hydrogen-containing gas.

(16) The hydrogen supply system according to any one of (1) to (15), wherein in the hydrogen production device, the amount of the fuel containing organic matter and water is adjusted to adjust The voltage between the fuel electrode and the oxidation electrode and/or the generation amount of the hydrogen-containing gas.

(17) The hydrogen supply system according to any one of (1) to (16), wherein in the hydrogen production device, the concentration of the fuel containing organic matter and water is adjusted to adjust the The voltage between the fuel electrode and the oxidation electrode and/or the generation amount of the hydrogen-containing gas.

(18) The hydrogen supply system according to any one of (1) to (17), wherein the operating temperature of the hydrogen production device is 100° C. or lower.

(19) The hydrogen supply system according to (18), wherein the operating temperature is 30 to 90°C.

(20) The hydrogen supply system according to any one of (1) to (19), wherein the organic substance supplied to the fuel electrode of the hydrogen production device is selected from alcohols, aldehydes, carboxylic acids, and ethers. One or two or more organic substances selected from the

(21) The hydrogen supply system described in (20), wherein the alcohol is methanol.

(22) The hydrogen supply system according to any one of (1) to (21), wherein the oxidizing agent supplied to the oxidation electrode of the hydrogen production device is an oxygen-containing gas or oxygen.

(23) The hydrogen supply system described in (22), wherein the oxidizing agent supplied to the oxidation electrode of the hydrogen production device is exhausted by air discharged from the other hydrogen production device.

(24) The hydrogen supply system according to any one of (1) to (21), wherein the oxidizing agent supplied to the oxidation electrode of the hydrogen production device is a liquid containing hydrogen peroxide.

(25) The hydrogen supply system according to any one of (1) to (24), wherein the separator of the hydrogen production device is a proton conductive solid electrolyte membrane.

(26) The hydrogen supply system according to (25), wherein the proton conductive solid electrolyte membrane is a perfluorocarbon sulfonic acid solid electrolyte membrane.

(27) The hydrogen supply system according to any one of (1) to (26), wherein the catalyst of the fuel electrode of the hydrogen production device is carbon powder loaded with Pt- Ru alloy catalyst.

(28) The hydrogen supply system according to any one of (1) to (27), wherein the catalyst of the oxidation electrode of the hydrogen production device is a catalyst in which Pt is supported on carbon powder. catalyst.

(29) The hydrogen supply system according to any one of (1) to (28), wherein a circulation device for the fuel containing organic matter and water is provided on the hydrogen production device.

(30) The hydrogen supply system according to any one of (1) to (29), wherein a device for absorbing carbon dioxide contained in the hydrogen-containing gas is installed on the hydrogen production device. Carbon dioxide absorber.

(31) The hydrogen supply system according to any one of (1) to (30), wherein a hydrogen permeable membrane is provided at an outlet of the hydrogen-containing gas of the hydrogen production device.

(32) The hydrogen supply system according to any one of (1) to (31), wherein no heat insulating material is provided for blocking heat generated by the hydrogen production device.

Here, the hydrogen production device used in the hydrogen supply system of (3) to (5) above has a device for supplying fuel and an oxidant to the hydrogen production cell constituting the hydrogen production device, and a pump, blower, etc. can be used for the device. In addition, in the case of (4) above, there is a discharge control device for deriving electric energy from the hydrogen production cell; in the case of (5) above, there is an electrolysis device for applying electric energy to the hydrogen production cell. In the case of (3) above, it is an open circuit state without a discharge control device for deriving electric energy from the hydrogen production cell and an electrolysis device for applying electric energy to the hydrogen production cell. Furthermore, the hydrogen production device used in the hydrogen supply system of (1) or (2) above includes the hydrogen production device used in the hydrogen supply system of (3) to (5) above. Furthermore, these hydrogen production devices have the ability to monitor the voltage of the hydrogen production cell and/or the amount of hydrogen-containing gas produced to control the supply or concentration of fuel and oxidant, and the derived electric energy (the above-mentioned case of (4)) or the applied electric energy (the above-mentioned (5) function). Here, the basic structure of the hydrogen production cell constituting the hydrogen production device has a fuel electrode provided on one surface of the separator for supplying fuel to the fuel electrode, and an oxide electrode is provided on the other surface of the separator for A structure for supplying an oxidizing agent to the above-mentioned oxidation electrode.

In addition, fuel cell vehicles are not limited to vehicles that only use fuel cells as the driving force of the vehicle, but also include hybrid vehicles that use other power sources.

The hydrogen supply system of the present invention uses a hydrogen production device capable of reforming fuel at temperatures from room temperature to 100°C, which is extremely low compared to conventional reforming temperatures, so that not only can the time required for start-up be shortened, but also The energy used to increase the temperature of the reformer can be reduced, and an insulating material for blocking the heat generated by the reformer can be eliminated, so that a hydrogen storage container that can be easily mounted on a hydrogen storage device such as a fuel cell vehicle can be realized , Fuel cell vehicles and other hydrogen storage tanks used to supply hydrogen supply hydrogen.

In addition, since the hydrogen-containing gas generated by the hydrogen production device does not contain CO, a device for removing CO is unnecessary.

In addition, the hydrogen production device used in the hydrogen supply system of the present invention can generate hydrogen without supplying electric energy to the hydrogen production cell from the outside, even in the case of having a device for deriving electric energy or having a device for applying electric energy from the outside , hydrogen can also be produced.

In the case of having a device for extracting electric energy, since the electric energy can be used to drive auxiliary equipment such as pumps and blowers, the effect is remarkable from the viewpoint of efficient use of energy.

Even if there is a device for applying electric energy from the outside, by supplying a small amount of electric energy from the outside to the hydrogen production cell, the effect of generating hydrogen exceeding the input electric energy can be realized.

Furthermore, in either case, by monitoring the voltage of the hydrogen production cell and/or the amount of hydrogen-containing gas produced, process control can be performed, and the hydrogen production equipment can be compacted, thereby reducing the cost of the hydrogen supply system. .

Description of drawings

Fig. 1(a) is a diagram showing an example of the system flow of the hydrogen supply system of the present invention.

Fig. 1(b) is a diagram showing an example of a hydrogen production device used in the hydrogen supply system of the present invention.

FIG. 2 is a schematic diagram of a hydrogen production cell (without external power supply) in Example 1. FIG.

Fig. 3 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 70°C) (hydrogen production example 1-1).

Fig. 4 is a graph showing the relationship between open circuit voltage and hydrogen generation rate at different temperatures (30 to 70°C) (hydrogen production example 1-1).

Fig. 5 is a graph showing the relationship (at a temperature of 70° C.) between the air flow rate, the hydrogen production rate, and the open circuit voltage (hydrogen production example 1-2) at different fuel flow rates.

Fig. 6 is a graph showing the relationship between the open circuit voltage and the hydrogen generation rate (at a temperature of 70° C.) at different fuel flow rates (hydrogen production example 1-2).

Fig. 7 is a graph showing the relationship (at a temperature of 70° C.) of the air flow rate, the hydrogen generation rate, and the open circuit voltage at different fuel concentrations (hydrogen production examples 1-3).

Fig. 8 is a graph showing the relationship between the open circuit voltage and the hydrogen generation rate (at a temperature of 70° C.) at different fuel concentrations (hydrogen production examples 1-3).

9 is a graph showing the relationship between the air flow rate, the hydrogen generation rate, and the open circuit voltage for electrolyte membranes of different thicknesses (hydrogen production examples 1-4).

Fig. 10 is a graph showing the relationship between open circuit voltage and hydrogen generation rate for electrolyte membranes of different thicknesses (hydrogen production examples 1-4).

Fig. 11 is a graph showing the relationship between air flow rate, hydrogen production rate, and open circuit voltage at different temperatures (30 to 90°C) (hydrogen production examples 1-5).

Fig. 12 is a graph showing the relationship between open circuit voltage and hydrogen generation rate (oxidant: air) at different temperatures (30 to 90°C) (hydrogen production examples 1-5).

Fig. 13 is a graph showing the relationship (at a temperature of 50° C.) between the air flow rate, the hydrogen generation rate, and the open circuit voltage (hydrogen production examples 1-6) at different fuel flow rates.

Fig. 14 is a graph showing the relationship between the open circuit voltage and the hydrogen generation rate (at a temperature of 50° C.) at different fuel flow rates (hydrogen production examples 1-6).

Fig. 15 is a graph showing the relationship (at a temperature of 50° C.) of the air flow rate, the hydrogen generation rate, and the open circuit voltage (hydrogen production examples 1-7) at different fuel concentrations.

Fig. 16 is a graph showing the relationship between the open circuit voltage and the hydrogen production rate (at a temperature of 50° C.) at different fuel concentrations (hydrogen production examples 1-7).

Fig. 17 is a graph showing the relationship (at a temperature of 50° C.) between the flow rate of the oxidizing gas, the hydrogen generation rate, and the open circuit voltage (hydrogen production examples 1-8) at different oxygen concentrations.

Fig. 18 is a graph showing the relationship between the open circuit voltage and the hydrogen generation rate (at a temperature of 50° C.) at different oxygen concentrations (hydrogen production examples 1-8).

Fig. 19 is a graph showing the relationship between the H ₂ O ₂ flow rate, the hydrogen production rate, and the open circuit voltage at different temperatures (30 to 90°C) (hydrogen production examples 1-10).

Fig. 20 is a graph showing the relationship between open circuit voltage and hydrogen generation rate (oxidizing agent: H ₂ O ₂ ) at different temperatures (30 to 90°C) (hydrogen production examples 1-10).

FIG. 21 is a schematic diagram of a hydrogen production cell (with a device for deriving electrical energy) in Example 2. FIG.

Fig. 22 is a graph showing the relationship between the current density and the operating voltage (discharge: temperature 50°C) derived at different air flow rates (hydrogen production example 2-1).

Fig. 23 is a graph showing the relationship between the operating voltage and the hydrogen production 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 current density and the operating voltage (discharge: temperature 30°C) derived at different air flow rates (hydrogen production example 2-2).

Fig. 25 is a graph showing the relationship between the operating voltage and the 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 current density and the operating voltage (discharge: temperature 70°C) derived at different air flow rates (hydrogen production example 2-3).

Fig. 27 is a graph showing the relationship between the operating voltage and the hydrogen production 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 current density and the operating voltage (discharge: temperature 90°C) derived at different air flow rates (hydrogen production example 2-4).

Fig. 29 is a graph showing the relationship between the operating voltage and the hydrogen production 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 derived at different temperatures (discharge: air flow rate of 50 ml/min).

Fig. 31 is a graph showing the relationship between operating voltage and hydrogen generation rate at different temperatures (discharge: air flow rate 50 ml/min).

Fig. 32 is a graph showing the relationship between the current density and the operating voltage derived at different temperatures (discharge: air flow rate 100 ml/min).

Fig. 33 is a graph showing the relationship between operating voltage and hydrogen production rate at different temperatures (discharge: air flow rate 100 ml/min).

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 example 2-5).

Fig. 35 is a graph showing the relationship between the operating voltage and the hydrogen generation rate (discharge: temperature 50°C) at different fuel flow rates (hydrogen production example 2-5).

Fig. 36 is a graph showing the relationship between the current density and the operating voltage (discharge: temperature 50°C) derived at different fuel concentrations (hydrogen production example 2-6).

Fig. 37 is a graph showing the relationship between the operating voltage and the hydrogen production rate (discharge: temperature 50°C) at different fuel concentrations (hydrogen production example 2-6).

Fig. 38 is a graph showing the relationship between current density and operating voltage (discharge: temperature 50°C) derived at different oxygen concentrations (hydrogen production example 2-7).

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 example 2-7).

Fig. 40 is a graph showing the relationship between current density and operating voltage derived at different temperatures (discharge: oxidizing agent H ₂ O ₂ ) (hydrogen production example 2-8).

Fig. 41 is a graph showing the relationship between operating voltage and hydrogen generation rate (discharge: oxidizing agent H ₂ O ₂ ) at different temperatures (hydrogen production example 2-8).

FIG. 42 is a schematic diagram of a hydrogen production cell (with means for applying electric energy from the outside) in Example 3. FIG.

Fig. 43 is a graph showing the relationship between the applied current density 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 the operating voltage and the 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 applied current density 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 applied current density 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 the operating voltage and the hydrogen production 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 applied current density 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 the operating voltage and the hydrogen production 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 applied current density 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 the operating voltage and the 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 at different temperatures (charging: air flow rate: 50 ml/min).

Fig. 57 is a graph showing the relationship between operating voltage and hydrogen generation rate at different temperatures (charging: air flow rate 50 ml/min).

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 example 3-5).

Fig. 60 is a graph showing the relationship between the operating voltage and the 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 example 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 example 3-6).

Fig. 63 is a graph showing the relationship between the operating voltage and the hydrogen generation rate (charging: temperature 50°C) at 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) at different fuel concentrations (hydrogen production example 3-6).

Fig. 65 is a graph showing the relationship between the applied current density and the hydrogen generation rate (charging: temperature 50°C) at different oxygen concentrations (hydrogen production example 3-7).

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 example 3-7).

Fig. 67 is a graph showing the relationship between operating voltage and energy efficiency (charging: temperature 50°C) at different oxygen concentrations (hydrogen production example 3-7).

Fig. 68 is a graph showing the relationship between the applied current density and the hydrogen generation rate (charging: oxidizing agent H ₂ O ₂ ) at different temperatures (hydrogen production example 3-8).

Fig. 69 is a graph showing the relationship between operating voltage and hydrogen generation rate (charging: oxidizing agent H ₂ O ₂ ) at different temperatures (hydrogen production example 3-8).

Fig. 70 is a graph showing the relationship between operating voltage and energy efficiency (charging: oxidizing agent H ₂ O ₂ ) at different temperatures (hydrogen production example 3-8).

Fig. 71 is a graph showing the relationship between the air flow rate and the hydrogen generation rate (open circuit: temperature 50°C) (Example 8).

Fig. 72 is a graph showing the relationship between open circuit voltage and hydrogen generation rate (open circuit: temperature 50°C) (Example 8).

Symbol Description

10: hydrogen production cell, 11: diaphragm, 12: fuel electrode,

13: Flow path for supplying fuel (methanol aqueous solution) containing organic matter and water,

14: oxidation electrode (air electrode), 15: flow path for supplying oxidant (air),

16: fuel pump, 17: air blower, 18: fuel flow regulating valve,

19: Air flow regulating valve, 20: Fuel tank, 21: Fuel regulating tank,

22: voltage regulator, 23: gas-liquid separator, 24: conduit.

Detailed ways

The best mode for carrying out the present invention is illustrated below.

In particular, the hydrogen production device used in the hydrogen supply system of the present invention is basically new, and what is described below is merely an embodiment, and the present invention is not limited thereto.

The basic structure of the hydrogen supply system of the present invention is that when the hydrogen storage device is a hydrogen storage container mounted on a fuel cell vehicle, it includes a hydrogen supply device for supplying hydrogen to the hydrogen storage container and a hydrogen supply device manufactured to supply hydrogen to the hydrogen supply device. A hydrogen production device for hydrogen-containing gas.

Fig. 1(a) shows an example of the system flow of the hydrogen supply system of the present invention.

A hydrogen supply device that supplies hydrogen to a hydrogen storage container mounted on a fuel cell vehicle includes, for example, a hydrogen booster, a high-pressure hydrogen storage tank, and a hydrogen distributor.

As the hydrogen booster, a hydrogen compressor pump is generally used, but any device capable of boosting hydrogen may be used. From the perspective of volumetric efficiency, the hydrogen pressure at the hydrogen booster outlet should be as high as possible, preferably more than 50 atmospheric pressure (5MPa), more preferably more than 100 atmospheric pressure (10MPa), and more preferably more than 200 atmospheric pressure (20MPa). The upper limit is not particularly limited, but it is preferably 1000 atmospheric pressure (100 MPa) or less during use.

After the hydrogen pressurization step, it is preferable to install a hydrogen storage tank (high-pressure hydrogen storage tank) for storing hydrogen. The form of the high-pressure hydrogen tank is not particularly limited as long as it is hydrogen that can withstand boosting pressure, and known forms can be used. In addition to high-pressure hydrogen storage tanks that store high-pressure hydrogen directly, hydrogen storage alloys can also be used. high-pressure hydrogen storage tanks.

The hydrogen gas is introduced from the high-pressure hydrogen storage tank to the hydrogen distributor. In addition, it is also possible not to directly communicate with the high-pressure hydrogen storage tank, but to introduce the outlet gas of the hydrogen booster into the hydrogen distributor. In this case, it is necessary to install piping for connecting the hydrogen booster and the hydrogen distributor.

The hydrogen dispenser is a device for supplying hydrogen to a hydrogen storage container of a fuel cell vehicle using hydrogen as fuel, and a known dispenser can be used. The hydrogen storage container may be a hydrogen storage container mounted on a fuel cell vehicle, or may be a hydrogen storage container in a state taken off from the fuel cell vehicle if the container can be removed from the fuel cell vehicle.

An example of a hydrogen production device used in the hydrogen supply system of the present invention is shown in FIG. 1( b ). The hydrogen production device has a hydrogen production cell (10) and auxiliary equipment for operating the hydrogen production device.

Since the hydrogen production device operates at a low temperature, a heater for raising the temperature is not required as shown in FIG. 1(b), but it can be installed as needed.

The structure of the hydrogen production cell (10) is as follows: a fuel electrode (12) is provided on one surface of the separator (11), and a flow path 13 for supplying fuel (methanol aqueous solution) containing organic matter and water to the fuel electrode (12) is provided. , and an oxide electrode (14) is provided on the other surface of the separator (11), and a flow path (15) for supplying an oxidizing agent (air) to the oxide electrode (14) is provided.

A fuel pump (16) for supplying methanol aqueous solution to the fuel electrode (12) and an air blower (17) for supplying air to the oxidation electrode (14) are provided as auxiliary equipment for operating the hydrogen production apparatus.

The flow path (13) of the fuel electrode is connected with the fuel pump (16) by a conduit through the flow regulating valve (18), and the flow path (15) of the oxidation electrode is connected with the air blower (17) by a conduit through the flow regulation valve (19).

Fuel (100% methanol) is stored in the fuel tank (20), then transferred to the fuel adjustment tank (21), mixed with water in the fuel adjustment tank (21), adjusted to, for example, about 3% methanol aqueous solution and supplied to the fuel pole (12).

In addition, when two or more hydrogen producing devices are used in combination, exhaust air discharged from another hydrogen producing cell (10) can be supplied as air to the oxide electrode (14) of one hydrogen producing cell (10).

For the hydrogen manufacturing device with the above structure, supply electric energy to the fuel pump (16) and air blower (17) to make it run, and when the flow regulating valve (18) is opened, the methanol aqueous solution is transferred from the fuel regulating tank by the fuel pump (16). (21) is supplied to the fuel electrode (12) through the flow path (13); in addition, when the flow regulating valve (19) is opened, the air is supplied to the oxidation electrode (14) by the air blower (17) through the flow path (15).

As a result, a reaction described later occurs between the fuel electrode and the oxidation electrode (air electrode), and hydrogen-containing gas is generated from the fuel electrode (12) side.

In addition, by setting a voltage regulator (22) for monitoring the voltage (open circuit voltage or operating voltage) of the hydrogen production cell (10) to control the supply or concentration of fuel and air and the derived or applied electric energy, it is possible to adjust The amount of hydrogen-containing gas produced.

The generated hydrogen-containing gas is separated into hydrogen-containing gas and unreacted aqueous methanol solution through a gas-liquid separator (23), and part or all of the unreacted aqueous methanol solution is formed by returning to the conduit (24) of the fuel adjustment tank (21) Circulation equipment for circulation. Depending on the situation, water may be supplied from outside the system.

The hydrogen production cell (10) in the hydrogen production device used in the hydrogen production system 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 oxide electrode (14) is arranged on the other surface of the diaphragm (11). For example, as such a structure, an MEA (electrolyte/electrode assembly) like that employed in a direct methanol fuel cell can be employed.

The method of manufacturing the MEA is not limited, and it can be manufactured by the same conventional method of joining the fuel electrode and the oxide electrode (air electrode) on both surfaces of the separator by hot pressing.

As the separator, a proton conductive solid electrolyte membrane used as a polymer electrolyte membrane in a fuel cell can be used. As the proton conductive solid electrolyte membrane, a perfluorocarbon sulfonic acid membrane having a sulfonic acid group, such as DuPont's Nafion membrane, is preferably used.

The fuel electrode and the oxide electrode (air electrode) are preferably electrically conductive and catalytically active electrodes, for example, can be produced by coating a catalyst slurry containing carbon powder on the gas diffusion layer and drying it. Catalysts loaded on carriers with such structures, binders such as PTFE resins, and substances for imparting ion conductivity such as Nafion solutions.

As the gas diffusion layer, a layer made of hydrophobically treated carbon paper or the like is preferable.

Any material can be used as the fuel electrode catalyst, but a catalyst in which a Pt-Ru alloy is supported on carbon powder is preferably used.

Any material can be used as the air electrode catalyst, but a catalyst in which Pt is supported on carbon powder is preferably used.

In the hydrogen production device with the above configuration, when fuel containing organic matter such as methanol aqueous solution is supplied to the fuel electrode, and an oxidizing agent such as air, oxygen, or hydrogen peroxide is supplied to the oxidation electrode (air electrode), under certain conditions, hydrogen peroxide is generated at the fuel electrode. Hydrogen-containing gas.

The hydrogen generation method in the hydrogen production device used in the hydrogen supply system of the present invention is completely different from the conventional hydrogen generation method, and it is difficult to explain the mechanism at present. The current presumptions are described below, and the possibility of a completely new reaction cannot be denied.

In the hydrogen production device used in the hydrogen supply system of the present invention, as will be described later, hydrogen-containing gas is generated from the fuel electrode side where methanol and water are supplied at a low temperature of 30 to 90°C. When no power is supplied to the hydrogen production cell from the outside, gas with a hydrogen concentration of about 70 to 80% is generated; when power is applied to the hydrogen production cell from the outside, gas with 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 electrodes. From these results, the following hydrogen generation mechanism is estimated. Hereinafter, in order to explain the mechanism simply, it will be described under an open circuit condition.

For example, when methanol is used as fuel in the hydrogen production apparatus of the present invention, it is considered that protons are first generated at the fuel electrode by the catalyst, as in the case of the direct methanol fuel cell.

CH ₃ OH+H ₂ O→CO ₂ +6H ⁺ +6e ^- ... (1)

In the case of using Pt-Ru as a catalyst, for the reaction of (1) above, it is considered that methanol is adsorbed on the surface of Pt, and the following electrochemical oxidation reaction occurs sequentially to generate adsorbed chemical species that are firmly adsorbed on the surface. Carry out ("Battery Handbook Third Edition" on February 20, 2001, issued by Maruzen Co., Ltd., page 406).

CH ₃ OH+Pt→Pt-(CH ₃ OH)ads

→Pt-(CH ₂ OH)ads+H ⁺ +e ^-

Pt-(CH ₂ OH)ads→Pt-(CHOH)ads+H ⁺ +e ^-

Pt-(CHOH)ads→Pt-(COH)ads+H ⁺ +e ^-

Pt-(COH)ads→Pt-(CO)ads+H ⁺ +e ^-

The aforementioned Pt-(CO)ads require adsorbed OH generated from water if they are to be further oxidized.

Ru+H ₂ O→Ru-(H ₂ O)ads

→Ru-(OH)ads+H ⁺ +e ^-

Ru-(OH)ads+Pt-(CO)ads→Ru+Pt+CO ₂ +H ⁺ +e ^-

In the case of a direct methanol fuel cell, the H ⁺ (proton) generated at the fuel electrode by the reaction of formula (1) moves in the proton-conducting solid electrolyte membrane, and the oxygen-containing gas supplied to the oxide electrode or the Oxygen reacts as follows.

3/2O ₂ +6H ⁺ +6e ^- →3H ₂ O...(2)

When the hydrogen production device is open-circuited, e ^- produced by the reaction of formula (1) is not supplied to the oxide electrode through an external circuit, so in order to produce the reaction of formula (2), it is necessary to supply e ^- by other reaction at the oxide electrode .

On the other hand, when a proton conductive solid electrolyte membrane such as Nafion is used in a direct methanol fuel cell, a "permeation" phenomenon in which CH ₃ OH permeates from the fuel electrode to the oxidation electrode side is known. The following electrolytic oxidation reaction of permeated methanol may occur at the oxidation pole.

CH ₃ OH+H ₂ O→CO ₂ +6H ⁺ +6e ^- ... (3)

When the reaction of the formula (3) occurs, the reaction of the formula (2) to which the e ^- produced by the reaction is supplied occurs.

Therefore, H ⁺ (proton) generated by the reaction of the formula (3) moves in the proton conductive solid electrolyte membrane, and the following reaction occurs at the fuel electrode to generate hydrogen.

6H ⁺ +6e ^- → 3H ₂ ……(4)

Here, H ⁺ and e ^- generated at the fuel electrode by the reaction of formula (1) move to the oxide electrode, and H ⁺ and e ^- generated at the oxide electrode by the reaction of formula (3) move to the fuel electrode are considered to cancel each other out apparently.

In this case, it can be presumed that the reaction of formula (2) occurs at the oxidation electrode due to the H ⁺ and e ^- formed by the reaction of formula (3), and the H produced by the reaction of formula (1) at the fuel electrode ⁺ and e ^- produce the reaction of formula (4).

Assuming that the reactions of the formulas (1) and (4) proceed on the fuel electrode and the reactions of the formulas (2) and (3) proceed on the oxide electrode, the following formula (5) can generally be considered to hold.

2CH ₃ OH+2H ₂ O+3/2O ₂ →2CO ₂ +3H ₂ O+3H ₂ ...(5)

The theoretical efficiency of this reaction is 59% (3 mol hydrogen exotherm/2 mol methanol exotherm).

But, for above-mentioned reaction, the standard electrode potential E0=0.046V of the reaction of (1) formula, the standard electrode potential E0=0.0V of the reaction of (4) formula, when combining the two under the standard state, due to (1) The situation of formula corresponds to positive pole, and the situation of formula (4) corresponds to negative pole, so that the reaction of formula (1) proceeds to the left, and the reaction of formula (4) also proceeds to the left, so hydrogen is not produced.

Here, in order to make the reaction of formula (1) proceed to the right and the reaction of formula (4) proceed to the right, it is necessary to make formula (1) correspond to the negative electrode and formula (4) correspond to the positive electrode, assuming that the entire fuel electrode is equal to When changing the potential, it is necessary to shift the methanol oxidation potential to a lower potential side, or to shift the hydrogen generation potential to a higher potential side.

However, when the fuel electrode is not equipotential, the reaction of formula (1) in which H ⁺ is extracted from methanol and water in the fuel electrode and the reaction of formula (4) in which H ⁺ combines with e ^- to form hydrogen may proceed simultaneously.

As described in the examples below, when the operating temperature is high, hydrogen is easily generated, and reaction heat from the outside is supplied, and the reactions of equations (1) and (3), which are endothermic reactions, proceed to the right.

For methanol, in addition to the reactions of (1) and (3), due to the permeation phenomenon, the methanol permeated from the fuel electrode will have the following side reaction of being oxidized by oxygen on the surface of the air electrode catalyst.

2CH ₃ OH+3/2O ₂ →CO ₂ +2H ₂ O...(6)

Since the reaction of the formula (6) is an exothermic reaction, it can be understood that the heat of the reactions of the formulas (1) and (3) is supplied by the exothermic reaction.

In the case of the hydrogen production device (hereinafter referred to as "open circuit condition") used in the hydrogen supply system of the invention according to claim 3 of the present application, as can be seen from the examples described later, if the supply amount of oxygen (air) decreases , when the open circuit voltage reaches 300-800mV, hydrogen will be generated. This is presumed to be that the oxidation of methanol passing through the air electrode side is suppressed by the formula (6), and the H ⁺ formation reaction of the formula (3) becomes dominant. Hydrogen is thus produced by the reaction of formula (4).

In the case of the hydrogen production device (hereinafter referred to as "discharge condition") used in the hydrogen supply system of the invention according to claim 4 of the present application, it is considered that hydrogen is generated by a mechanism similar to the hydrogen generation mechanism under the open circuit condition. . However, unlike the case of the open circuit condition, since an amount of H ⁺ equivalent to the discharge current moves from the fuel electrode to the oxide electrode, it is necessary to maintain the charge neutral condition of the battery as a whole, so it can be considered that the reaction of formula (1) wins at the fuel electrode. In formula (4), the reaction of formula (2) is better than formula (3) on the oxide pole.

As can be seen from the examples described later, when the discharge current becomes large (a large amount of e ^- is supplied to the oxidation pole), hydrogen is not generated when the discharge voltage is lower than 200 mV. Hydrogen is not produced.

In addition, even when a large amount of oxygen (air) is supplied, or the discharge voltage is higher than 600mV, hydrogen is not generated, which is presumed to be that the methanol permeated through the air electrode side is oxidized by the formula (6), so that ( 3) The H ⁺ generating reaction of the formula.

On the other hand, when the supply amount of oxygen (air) is small, if the discharge current decreases and the discharge voltage (operating voltage) is 200 to 600 mV, hydrogen will be generated. Oxidation of the formula (6) is suppressed, the H ⁺ generation reaction of the formula (3) becomes dominant, and hydrogen is generated by the reaction of the formula (4).

In the case of the hydrogen production device (hereinafter referred to as "charging condition") used in the hydrogen supply system of the invention according to claim 5 of the present application, it is also considered that hydrogen is generated by a mechanism similar to the hydrogen generation mechanism under the open circuit condition. However, unlike the case of the open circuit condition, since the H ⁺ equivalent to the electrolysis current moves from the oxide electrode to the fuel electrode, it is necessary to maintain the electrical neutral condition of the battery as a whole, so it can be considered that the reaction of formula (4) wins at the fuel electrode. In formula (1), the reaction of formula (3) is better than that of formula (2) on the oxide pole.

That is, in the charging condition of the present invention, since electric energy is applied from the outside with the fuel electrode as the cathode and the oxide electrode as the anode (e ^- is supplied from the outside to the fuel electrode), electrolysis basically occurs. It can be seen that when the applied electric energy (applied voltage) is increased, more hydrogen will be generated. This can be considered to be that the ^e- supplied from the outside to the fuel electrode increases, and the electrolytic oxidation reaction of methanol in the formula (3) and The reaction of formula (4) is 6H ⁺ +6e ^- → 3H ₂ .

However, as will be 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 600 mV, the energy efficiency increases. This is presumed to be that within this range, as described above, even in the case of open-circuit conditions or discharge conditions in which electric energy is not supplied from the outside, the oxidation of methanol permeating the air electrode side is suppressed by the formula (6), The H ⁺ generation reaction of the formula (3) becomes dominant, thereby generating hydrogen by the H ⁺ generation reaction of the formula (4); in the case of charging conditions, except for the part where electric energy is applied from the outside, the same as the above-mentioned open circuit conditions or discharge conditions The case also produces hydrogen.

Here, what the potential of the battery means will be described. Generally, the voltage of a battery in which gas electrodes are formed at both poles with an electrolyte membrane sandwiched between them is generated by the difference in chemical potential of conductive ions in the electrolyte at the two poles.

That is, when the polarization at the two electrodes is not considered, since the proton (hydrogen ion) conductive solid electrolyte membrane is used as the electrolyte, the observed voltage represents the difference in the chemical potential of hydrogen at the two electrodes of the battery, the so-called hydrogen partial pressure.

In the present invention, as described in the following examples, when the voltage between the fuel electrode and the oxidation electrode is in a certain range, hydrogen is generated from the fuel electrode side; The reactions of the above formulas (1) to (6) are carried out to generate hydrogen.

The hydrogen production device used in the hydrogen supply system of the present invention, in the case of not supplying electric energy to the hydrogen production cell from the outside, in the case of deriving electric energy from the outside, and in the case of applying electric energy from the outside, all by adjusting the fuel electrode The voltage (open circuit voltage or operating voltage) between the electrode and the oxide electrode (air electrode) can adjust the amount of hydrogen-containing gas generated.

It can be seen from the examples described later that in the case of open circuit conditions, the open circuit voltage is 300 to 800 mV to generate hydrogen; in the case of discharge conditions, the discharge voltage (operating voltage) is 200 to 600 mV to generate hydrogen; in the case of charge conditions, Hydrogen is generated at an applied voltage (operating voltage) of 300 to 1000 mV (400 to 600 mV has high energy efficiency). Therefore, the amount of hydrogen-containing gas produced can be adjusted by adjusting the open circuit voltage or operating voltage within this range.

As shown in the following examples, the open circuit voltage or operating voltage and/or the amount of hydrogen-containing gas generated (hydrogen generation rate) can be adjusted by adjusting the supply amount of the oxidizing agent (oxygen-containing gas or oxygen, liquid containing hydrogen peroxide), Adjustment is performed by adjusting the concentration of the oxidizing agent (oxygen concentration in the oxygen-containing gas), adjusting the supply amount of the fuel containing the organic matter, and adjusting the concentration of the fuel containing the organic matter.

In addition, in addition to the above, in the case of discharge conditions, by adjusting the electric energy derived to the outside (by adjusting the current drawn to the outside, and by using a power supply that can control a constant voltage, that is, a so-called potentiostat) voltage), in the case of charging conditions, by adjusting the applied electrical energy (by adjusting the applied current, but also by using a power supply that can control a constant voltage, a so-called potentiostat), it is possible to adjust the operating voltage and/or Or the generation amount of hydrogen-containing gas.

In the hydrogen production device used in the hydrogen supply system of the present invention, since the fuel containing organic matter can be decomposed at 100°C or lower, the operating temperature of the hydrogen production device can be 100°C or lower. The operating temperature is preferably 30 to 90°C. By adjusting the operating temperature in the range of 30-90°C, as described in the following examples, the open circuit voltage or operating voltage and/or the amount of hydrogen-containing gas generated can be adjusted.

In addition, for the conventional reforming technology that must be operated at 100°C or higher, water turns into steam, and fuel containing organic matter is gasified. Under such conditions, even if hydrogen is generated, additional equipment for hydrogen separation is required, so that The present invention is advantageous in this regard.

However, if the fuel containing organic matter is decomposed at a temperature above 100°C, there will be the above-mentioned disadvantages, but the present invention does not deny the operation of the hydrogen production device in the hydrogen supply system of the present invention at a temperature exceeding 100°C to a certain extent .

From the presumed principle, the fuel containing organic matter can be a liquid or gaseous fuel that passes through a proton conductive membrane and is electrochemically oxidized to generate protons, and preferably contains alcohols such as methanol, ethanol, ethylene glycol, and isopropanol. , aldehydes such as formaldehyde, carboxylic acids such as formic acid, and ethers such as diethyl ether are liquid fuels. Since the fuel containing 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 above-mentioned fuel is a solution containing at least methanol and water, and its concentration can be arbitrarily selected in the field of generating hydrogen-containing gas.

A gaseous or liquid oxidizing agent can be used as the oxidizing agent. Oxygen-containing gases or oxygen are preferred as gaseous oxidizing agents. The oxygen concentration of the oxygen-containing gas is particularly preferably 10% or more. Liquids containing hydrogen peroxide are preferred as liquid oxidizing agents.

In the present invention, since the fuel put into the hydrogen production device is consumed once in the device, and the ratio of decomposition into hydrogen is low, it is preferable to install fuel recycling equipment to increase the conversion rate to hydrogen.

The hydrogen production device used in the hydrogen production system of the present invention has a device for taking out hydrogen-containing gas from the fuel electrode side, which is a device for recovering hydrogen, preferably also carbon dioxide. Since the operation is performed at a low temperature of 100° C. or lower, a carbon dioxide absorbing unit for absorbing carbon dioxide contained in hydrogen-containing gas can be provided in a simple manner.

In addition, the hydrogen-containing gas generated on the fuel electrode side of the hydrogen production device contains not only carbon dioxide, but also water, unreacted raw materials, etc. Only hydrogen permeates selectively, thereby obtaining high-purity hydrogen.

The hydrogen permeable membrane is not limited, and a hydrogen permeable metal membrane having a thickness of 5 to 50 μm formed on the inorganic porous layer and selectively permeable to hydrogen can be used. The inorganic porous layer is a carrier for holding the hydrogen permeable metal film, and is formed of porous stainless steel nonwoven fabric, ceramics, glass, etc. with a thickness in the range of 0.1 mm to 1 mm. The hydrogen-permeable metal film can use a Pd-containing alloy, a Ni-containing alloy, or a V-containing alloy, preferably a Pd-containing alloy. Pd-containing alloys may, for example, be Pd·Ag alloys, Pd·Y alloys, Pd·Ag·Au alloys or the like.

High-purity hydrogen with a purity of 99.999% or more can be obtained from the above hydrogen permeable membrane, and this high-purity hydrogen can be used as a fuel for fuel cells or as a process gas for manufacturing semiconductor devices.

Examples (hydrogen production examples) of the present invention are shown below, but the ratios of the catalyst, PTFE, and Nafion, etc., and the thickness of the catalyst layer, gas diffusion layer, and electrolyte membrane can be appropriately changed, and are not limited to these examples.

Example 1

The following shows an example of the case where hydrogen is produced by the hydrogen production device (open circuit condition) used in the hydrogen supply system of the invention according to claim 3 of the present application.

Hydrogen production example 1-1

The hydrogen producing cells in Example 1 (Manufacturing Examples 1-1 to 1-10) had the same structure as a typical direct methanol fuel cell.

The outline of this hydrogen production cell is shown in FIG. 2 .

That is, using a proton-conducting electrolyte membrane (Nafion 115) manufactured by DuPont as an electrolyte, carbon paper (manufactured by Toray) was immersed in a 5% polytetrafluoroethylene dispersion for the air electrode, and then fired at 360°C. However, hydrophobic treatment is carried out, and an air electrode catalyst slurry is coated on one surface thereof to form a gas diffusion layer with an air electrode catalyst. Manufactured by precious metals), PTFE fine powder and 5% Nafion solution (manufactured by Aldrich). Here, the weight ratio of the air electrode catalyst, PTEF, and Nafion is 65%:15%:20%. The catalyst amount of the air electrode produced in this way was 1 mg/cm ² in terms of platinum.

Furthermore, the same method is used to hydrophobically treat the carbon paper, and then coat the fuel electrode catalyst slurry on one side thereof, thereby forming a gas diffusion layer with the fuel electrode catalyst. The fuel electrode catalyst slurry is mixed with the fuel electrode catalyst (Pt-Ru-loaded carbon, manufactured by Tanaka Precious Metals), PTFE fine powder, and 5% Nafion solution. Here, the weight ratio of the fuel electrode catalyst, PTEF, and Nafion is 55%:15%:30%. The amount of catalyst in the fuel electrode produced in this way was 1 mg/cm ² in terms of Pt—Ru.

The above-mentioned electrolyte membrane, gas diffusion layer with air electrode catalyst, and gas diffusion layer with fuel electrode catalyst were bonded by thermocompression at 40°C and 100kg/cm ² to fabricate an MEA. The effective electrode area of the thus fabricated MEA was 60.8 cm ² . The catalyst layers of the air electrode and the fuel electrode and the gas diffusion layers of the air electrode and the fuel electrode had thicknesses of about 30 μm and 170 μm, respectively, and were substantially the same.

Flow paths for air flow and fuel flow are respectively provided, and the MEA is sandwiched between an air electrode separator and a fuel electrode separator made of graphite impregnated with phenolic resin in order 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 around the MEA.

The hydrogen production cell produced in this way is placed in a hot air circulation type electric furnace, and at a battery temperature (operating temperature) of 30 to 70°C, air flows at a flow rate of 0 to 400 ml/min on the air electrode side, and at a flow rate of 2 to the fuel electrode side. The voltage difference (open circuit voltage) between the fuel electrode and the air electrode, the amount of gas generated on the fuel electrode side, and the gas composition were studied by flowing 0.5M to 2M methanol aqueous solution (fuel) at a flow rate of ~15ml/min.

First, the flow rate of methanol aqueous solution (fuel) supplied to the battery was kept constant at 8 ml/min, and the air flow rate was varied at each temperature of 30°C, 50°C, and 70°C to measure the amount of gas generated from the fuel electrode side. Gas generation was measured using the water displacement method. In addition, the hydrogen concentration in the generated gas was analyzed by gas chromatography to determine the hydrogen generation rate.

The result is shown in Figure 3.

Thus, at each temperature, it was confirmed that hydrogen was generated from the fuel electrode side of the cell by reducing the air flow rate. It is also known that the higher the temperature, the higher the hydrogen generation rate. Furthermore, the relationship between the air flow rate and the open circuit voltage of the battery was studied, and it was found that the open circuit voltage of the battery tended to decrease as the air flow rate decreased.

In FIG. 4, the results of FIG. 3 are summarized as a relationship between the open circuit voltage and the hydrogen generation rate.

From this, it can be seen 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 production rate was observed around 450 mV at any temperature.

Next, gas was generated under the conditions of a temperature of 70°C, 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, CO was not detected.

Hydrogen production example 1-2

Use the same hydrogen production cell as in Hydrogen Production Example 1-1, and then change the air flow rate under the condition that the cell temperature is 70°C and the flow rate of methanol aqueous solution (fuel) with a concentration of 1M is 2, 8, and 15 ml/min, as shown in Fig. 5 The relationship between the fuel flow rate, the air flow rate, the hydrogen generation rate, and the open circuit voltage of the battery at this time is shown.

It can be seen that the hydrogen generation rate is high when the fuel flow rate is small.

The results of FIG. 5 are shown in FIG. 6 as a relationship between the open circuit voltage and the hydrogen generation rate.

From this, it can be seen that the hydrogen generation rate under each condition depends on the open circuit voltage. In addition, at any of the fuel flow rates, as in Hydrogen Production Example 1-1, a peak of the hydrogen production rate was observed around 450 mV.

Furthermore, in this production example, the conditions (operating temperature 70° C., fuel concentration 1 M , fuel flow rate 2ml/min, air flow rate 100ml/min), the hydrogen concentration in the gas produced is about 70% as a result.

Hydrogen Production Example 1-3

Use the same hydrogen production cell as in Hydrogen Production Example 1-1, and then change the air flow rate under the conditions of cell temperature 70°C, methanol aqueous solution (fuel) at a constant flow rate of 8 ml/min, and fuel concentration of 0.5, 1, and 2M. , FIG. 7 shows the relationship between the fuel flow rate, the air flow rate, the hydrogen generation rate, and the open circuit voltage of the battery at this time.

From this, it can be seen that when the fuel concentration is low, the hydrogen generation rate is high.

In FIG. 8, the results of FIG. 7 are summarized as a relationship between the open circuit voltage and the hydrogen production rate.

From this, it can be seen that the hydrogen generation rate under each condition depends on the open circuit voltage, and hydrogen is generated at 300 to 600 mV. In addition, at any fuel concentration, the peak value of the hydrogen production rate was observed around 450 mV as in Hydrogen Production Example 1-1.

Hydrogen Production Examples 1-4

Next, the effect of the thickness of the electrolyte membrane on the amount of gas generation was studied.

In hydrogen production examples 1-1 to 1-3, Nafion 115 (thickness: 130 μm) manufactured by DuPont was used as the electrolyte membrane, and the same Nafion 112 (thickness: 50 μm) manufactured by DuPont was used to form the same hydrogen production cell. The air flow rate was changed under the conditions of 70°C, fuel concentration 1M, and fuel flow rate 8ml/min, and the relationship between the fuel flow rate, the air flow rate, the hydrogen production rate, and the open circuit voltage of the battery was studied.

Nafion 115 and Nafion 112 are made of the same material, and the influence of the thickness of the electrolyte membrane was purely studied here. The research results are shown in Figure 9.

In FIG. 10, the results of FIG. 9 are summarized as a relationship between the open circuit voltage and the hydrogen generation rate.

From this, it can be seen that the hydrogen generation rate is substantially the same for any electrolyte membrane. As can be seen from the figure, the hydrogen production rate under each condition depends on the open circuit voltage, and the peak value of the hydrogen production rate was observed around 450 mV.

Hydrogen Production Examples 1-5

Using the same hydrogen production cell as in Hydrogen Production Example 1-1, the hydrogen production cell was placed in a hot air circulation type electric furnace, and at the battery temperature of 30°C, 50°C, 70°C, and 90°C, the flow rate was Air was flowed at 0 to 250ml/min, and 1M methanol aqueous solution (fuel) was flowed at a flow rate of 5ml/min on the fuel electrode side, and the open circuit voltage of the battery at this time and the hydrogen generation rate at the fuel electrode side were studied.

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 generated from the fuel electrode side of the cell by reducing the air flow rate at each temperature. It is also known that the higher the temperature, the higher the hydrogen generation rate. Furthermore, 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 tends to decrease as the air flow rate decreases.

The results of FIG. 11 are shown in FIG. 12 as a relationship between the open circuit voltage and the hydrogen production rate.

From this, it can be seen that the hydrogen generation rate depends on the open circuit voltage, and hydrogen is generated at 300 to 700 mV. In addition, at 30°C to 70°C, the peak of the hydrogen generation rate was observed around 470 to 480mV; at 90°C, the peak value of the hydrogen generation rate was observed at around 440mV.

Hydrogen Production Examples 1-6

Using the same hydrogen production cell as in Hydrogen Production Example 1-1, the air flow rate was changed under the conditions of cell temperature of 50°C and fuel flow rate of 1.5, 2.5, 5.0, 7.5, and 10.0 ml/min, as shown in Fig. 13 The relationship between fuel flow, air flow and hydrogen generation rate.

From this, it can be seen that, unlike the result of 70° C. in the above-mentioned hydrogen production example 1-2, when the fuel flow rate is large, the hydrogen production rate tends to increase.

The results of FIG. 13 are shown in FIG. 14 as a relationship between the open circuit voltage and the hydrogen production rate.

From this, it can be seen 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 around 450 to 500 mV.

Calculate the methanol consumption and the hydrogen generation rate in the fuel when the fuel flow rate is changed, and use the following formula to calculate the energy efficiency under the open circuit condition (this energy efficiency is different from the energy efficiency under the charging condition calculated by the calculation formula described later) . 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 a fuel flow rate of 2.5 ml/min.

Energy Efficiency in Open Circuit Conditions (%)

=(standard enthalpy change of hydrogen produced/enthalpy change of methanol consumed)×100

Hydrogen Production Examples 1-7

Using the same hydrogen production cell as in Hydrogen Production Example 1-1, the air was changed under the conditions of cell temperature of 50°C, methanol aqueous solution (fuel) at a constant flow rate of 5ml/min, and fuel concentration of 0.5, 1, 2, and 3M. As for the flow rate, FIG. 15 shows the relationship between the air flow rate and the hydrogen generation rate at this time.

As the fuel concentration decreases, the air flow becomes smaller and a peak in the hydrogen generation rate is observed.

In FIG. 16, the results of FIG. 15 are summarized as a relationship between the open circuit voltage and the hydrogen generation rate.

From this, it can be seen 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, at any fuel concentration, the peak value of the hydrogen production rate was observed around 470 mV.

Hydrogen Production Examples 1-8

Use the same hydrogen production cell as in Hydrogen Production Example 1-1 (but the air electrode forms the oxidation electrode of the flowing oxidizing gas), at a cell temperature of 50°C, a fuel concentration of 1M, a fuel flow rate of 5ml/min, and an oxygen concentration of 10, The flow rate of the oxidizing gas was changed under the conditions of 21, 40, and 100%. The relationship between the flow rate of the oxidizing gas and the hydrogen generation rate at this time is shown in FIG. 17 . Here, air is used for a gas with an oxygen concentration of 21%, a gas prepared by mixing nitrogen with air for a gas with an oxygen concentration of 10%, and a gas prepared by mixing oxygen (oxygen concentration 100%) with air for a gas with an oxygen concentration of 40%. gas.

As the oxygen concentration increased, the oxidizing gas flow rate decreased, and a peak in the hydrogen generation rate was observed.

The results of FIG. 17 are shown in FIG. 18 as a relationship between the open circuit voltage and the hydrogen generation rate.

From this, it can be seen 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 of the hydrogen generation rate was observed around 490 to 530 mV.

Hydrogen Production Examples 1-9

Using the same hydrogen production cell as in Hydrogen Production Example 1-1, at a cell temperature of 50°C, flow air at a flow rate of 60ml/min on the air electrode side, and flow 1M methanol at a flow rate of 2.6ml/min at the fuel electrode side Aqueous solution (fuel), thereby generating gas, sampling 200cc, using gas chromatography to measure the concentration of CO in the gas. As a result, CO was not detected from the sample (1 ppm or less). Here, the open circuit voltage of the cell under these conditions was 477 mV, and the hydrogen generation rate was about 10 ml/min.

Hydrogen Production Examples 1-10

Using the same hydrogen production cell as in Hydrogen Production Example 1-1 (but the air electrode forms the oxidation electrode of flowing liquid hydrogen peroxide), the hydrogen production cell is set in a hot air circulation type electric furnace, and the battery temperature is 30 ° C, 50 ° C , 70°C and 90°C, flow 1M H ₂ O ₂ (hydrogen peroxide) at a flow rate of 1-8ml/min on the oxidation side, and flow 1M methanol aqueous solution (fuel) at a flow rate of 5ml/min at the fuel side. ), the open circuit voltage of the battery at this time and the hydrogen generation rate at the fuel electrode side were studied.

The relationship between the H ₂ O ₂ flow rate and the hydrogen generation rate is shown in FIG. 19 .

As in the case of hydrogen production example 1-1, it was confirmed that hydrogen was generated from the fuel electrode side of the cell by decreasing the flow rate of H ₂ O ₂ at each temperature. It is also known that the higher the temperature, the higher the hydrogen generation rate. Furthermore, the relationship between the flow rate of H ₂ O ₂ and the open circuit voltage of the battery was studied, and it was confirmed that the open circuit voltage of the battery tended to decrease as the flow rate of H ₂ O ₂ decreased.

The results of FIG. 19 are shown in FIG. 20 as a relationship between the open circuit voltage and the hydrogen production rate.

From this, it can be seen 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, at 30°C to 50°C, the peak value of the hydrogen generation rate is observed around 500mV, and at 70°C to 90°C, the peak value of the hydrogen generation rate is observed around 450mV.

The important point here is that in the above-mentioned Example 1, no current or voltage is applied to the hydrogen production cell from the outside, and only the open circuit voltage is measured with a potentiometer with an internal resistance greater than or equal to 1 GΩ, and only fuel and oxidant are supplied at the same time.

In other words, the hydrogen producing cell of Example 1 can convert a part of the fuel into hydrogen without externally supplying energy other than supplying the fuel and the oxidizing agent.

In addition, it is reforming at an astonishingly low temperature of 30 to 90°C, and it is considered to be a completely new hydrogen production device that has never existed before, and the effect of using this hydrogen production device in a hydrogen supply system is remarkable.

Example 2

An example of the case where hydrogen is produced by the hydrogen production device (discharge condition) used in the hydrogen supply system of the invention according to claim 4 of the present application is shown below.

Hydrogen production example 2-1

Fig. 21 shows the outline of a hydrogen production cell provided with an electric energy derivation device in Example 2 (Production Examples 2-1 to 2-8).

The structure of the hydrogen production cell is the same as that of the hydrogen production example 1-1 except that the fuel electrode is used as the negative electrode and the air electrode is used as the positive electrode to provide electrical energy exporting equipment.

The hydrogen production cell is set in a hot air circulation type electric furnace, and at a cell temperature (operating temperature) of 50° C., flow air at a flow rate of 10 to 100 ml/min on the air electrode side, and 5 ml/min at a flow rate on the fuel electrode side. While flowing 1M methanol aqueous solution (fuel), while changing the current flowing between the air electrode and the fuel electrode, 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 studied. In addition, the hydrogen concentration in the generated gas was analyzed by gas chromatography to obtain the hydrogen generation rate.

In this test, the relationship between the derived current density and the operating voltage is shown in FIG. 22 .

As the air flow rate becomes smaller, the operating voltage decreases, and it is observed that the limit current density that can be discharged decreases.

In FIG. 23, the results of FIG. 22 are summarized as a relationship between the operating voltage and the hydrogen generation rate.

From this, it can be seen that the hydrogen generation rate (hydrogen generation amount) tends to depend on the operating voltage, and gas is generated at an operating voltage of 300 to 600 mV. In addition, it can be seen that hydrogen is most likely to be generated when the air flow rate is 50-60ml/min. Furthermore, when the air flow rate is larger than this flow rate, hydrogen is hardly generated, and when it is 100 ml/min, hydrogen is hardly generated.

Next, gas was generated under the conditions of high hydrogen generation rate, temperature 50°C, fuel flow rate 5ml/min, air flow rate 60ml/min, and current density 8.4mA/cm ² , and the hydrogen concentration in the gas was measured by gas chromatography.

As a result, the generated gas contained about 74% hydrogen, and the hydrogen generation rate was 5.1 ml/min. In addition, CO was not detected.

Hydrogen production example 2-2

Using the same hydrogen production cell as in Hydrogen Production Example 2-1, at a cell temperature of 30°C, flow air at a flow rate of 30 to 100 ml/min on the air electrode side, and flow 1M hydrogen at a flow rate of 5 ml/min at the fuel electrode side. Methanol aqueous solution (fuel), at this time, while changing the current flowing between the air electrode and the fuel electrode, the operating voltage of the fuel electrode and the air electrode, and the generation rate of hydrogen generated on the fuel electrode side were studied.

In this test, the relationship between the derived current density and the operating voltage is shown in FIG. 24 .

As the air flow rate becomes smaller, the operating voltage decreases, and it is observed that the limit current density that can be discharged decreases.

In FIG. 25, the results of FIG. 24 are summarized as a relationship between the operating voltage and the hydrogen generation rate.

From this, it can be seen 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 was also found that hydrogen was generated at an air flow rate of 30 to 70 ml/min. At 100 ml/min, almost no hydrogen is generated.

Hydrogen production example 2-3

Use the same hydrogen production cell as in Hydrogen Production Example 2-1. At a cell temperature of 70°C, flow air at a flow rate of 50 to 200 ml/min on the air electrode side, and flow 1M hydrogen at a flow rate of 5 ml/min at the fuel electrode side. Methanol aqueous solution (fuel), at this time, while changing the current flowing between the air electrode and the fuel electrode, the operating voltage of the fuel electrode and the air electrode, and the generation rate of hydrogen generated on the fuel electrode side were studied.

In this test, the relationship between the derived current density and the operating voltage is shown in FIG. 26 .

As the air flow rate becomes smaller, the operating voltage decreases, and it is observed that the limit current density that can be discharged decreases.

In FIG. 27, the results of FIG. 26 are summarized as a relationship between the operating voltage and the hydrogen generation rate.

From this, it can be seen 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 was also found that hydrogen is easily generated when the air flow rate is 50 to 100 ml/min. When the air flow is increased to like 150, 200ml/min, almost no hydrogen is produced.

Hydrogen Production Example 2-4

Using the same hydrogen production cell as in Hydrogen Production Example 2-1, at a cell temperature of 90°C, flow air at a flow rate of 50 to 250 ml/min on the air electrode side, and flow 1M hydrogen at a flow rate of 5 ml/min at the fuel electrode side. Methanol aqueous solution (fuel), at this time, while changing the current flowing between the air electrode and the fuel electrode, the operating voltage of the fuel electrode and the air electrode, and the generation rate of hydrogen generated on the fuel electrode side were studied.

In this test, the relationship between the derived current density and the operating voltage is shown in FIG. 28 .

As the air flow rate becomes smaller, the operating voltage decreases, and it is observed that the limit current density that can be discharged decreases.

In FIG. 29, the results of FIG. 28 are summarized as a relationship between the operating voltage and the hydrogen generation rate.

From this, it can be seen 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. In addition, it was found that hydrogen is easily generated when the air flow rate is 50 to 100 ml/min. At 250 ml/min, almost no hydrogen is generated.

Next, the relationship between the current density and the operating voltage derived when the air flow rate is 50 ml/min at each temperature of 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. Figure 31.

From this, it can be seen that the rate of hydrogen generation tends to depend on temperature, and when the temperature is high, hydrogen is generated at a low operating voltage, and the amount of hydrogen generation increases.

Furthermore, the relationship between the current density and the operating voltage derived when the air flow rate is 100 ml/min at each temperature of 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. Figure 33.

From this, it can be seen that the rate of hydrogen generation tends to depend on temperature, and when the temperature is high, hydrogen is generated at a low operating voltage, and the amount of hydrogen generation increases. In addition, when the air flow rate is increased to 100 ml/min, hydrogen is hardly generated at a temperature as low as 30°C or 50°C.

Hydrogen production example 2-5

Using the same hydrogen production cell as in Hydrogen Production Example 2-1, at a cell temperature of 50°C, flow air at a flow rate of 50ml/min on the air electrode side, and change the fuel flow rate at the fuel electrode side to 1.5, 2.5, 5.0, 7.5 , 10.0ml/min, while changing the current flowing between the air electrode and the fuel electrode, the operating voltage of the fuel electrode and the air electrode, and the generation rate of hydrogen generated on the fuel electrode side were studied.

In this test, the relationship between the derived current density and the operating voltage is shown in FIG. 34 .

It can be observed that even if the fuel flow rate is changed, the dischargeable limit current density does not change greatly.

In FIG. 35, the results of FIG. 34 are summarized as a relationship between the operating voltage and the hydrogen generation rate.

From this, it can be seen that the hydrogen generation rate under each condition depends on the operating voltage, and hydrogen is generated at 300 to 500 mV. In addition, a high hydrogen generation rate was observed around 450 to 500 mV.

It can be seen that the hydrogen generation rate does not depend much on the fuel flow rate.

Hydrogen Production Example 2-6

Using the same hydrogen production cell as in Hydrogen Production Example 2-1, at a cell temperature of 50°C, flow air at a flow rate of 50ml/min on the air electrode side, and a constant flow rate of 5ml/min fuel at the fuel electrode side, and change the fuel Concentrations were 0.5, 1, 2, and 3 M. At this time, the current flowing between the air electrode and the fuel electrode was changed, and the operating voltage of the fuel electrode and the air electrode, and the generation rate of hydrogen generated on the fuel electrode side were studied.

In this test, the relationship between the derived current density and the operating voltage is shown in FIG. 36 .

As the fuel concentration increases, the operating voltage decreases and the dischargeable limiting current density is observed to decrease.

In FIG. 37, the results of FIG. 36 are summarized as a relationship between the operating voltage and the hydrogen generation rate.

From this, it can be seen that the hydrogen generation rate under each condition depends on the operating voltage, and hydrogen is generated at 300 to 600 mV.

When the fuel concentration is 1M, hydrogen is most likely to be produced.

Hydrogen production example 2-7

Use the same hydrogen production cell as in Hydrogen Production Example 2-1 (but the air electrode forms the oxidation electrode for flowing oxidizing gas), and at a cell temperature of 50°C, flow a fuel concentration of 1M at a constant flow rate of 5ml/min on the fuel electrode side On the side of the oxidation electrode, the oxidizing gas flows at a flow rate of 14.0ml/min, and the oxygen concentration is changed to 10, 21, 40, and 100%. At this time, the current flowing between the oxidation electrode and the fuel electrode is changed, and the fuel electrode and the The operating voltage of the oxide electrode and the generation rate of hydrogen generated on the fuel electrode side were studied. Here, air is used as the gas with an oxygen concentration of 21%, nitrogen gas is mixed with air for a gas with an oxygen concentration of 10%, and oxygen (100% oxygen concentration) is mixed with air for a gas with an oxygen concentration of 40%.

In this test, the relationship between the derived current density and the operating voltage is shown in FIG. 38 .

When the oxygen concentration is low, the operating voltage is lowered, and the dischargeable limiting current density is observed to be lowered.

In FIG. 39, the results of FIG. 38 are summarized as a relationship between the operating voltage and the hydrogen generation rate.

From this, it can be seen 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, a tendency for the hydrogen generation rate to increase is observed.

Hydrogen Production Example 2-8

Use the same hydrogen production cell as in Hydrogen Production Example 2-1 (but the air electrode forms the oxidation electrode of flowing liquid hydrogen peroxide), set the hydrogen production cell in a hot air circulation type electric furnace, and the battery temperature is 30°C, 50°C, At 70°C and 90°C, flow 1M methanol aqueous solution (fuel) at a flow rate of 5ml/min on the fuel electrode side, and flow _{1M H2O2} (hydrogen peroxide) at a flow rate of 2.6-5.5ml/min on the oxidation electrode side At this time, while changing the current flowing between the oxide electrode and the fuel electrode, the operating voltage of the fuel electrode and the oxide electrode, and the generation rate of hydrogen generated on the fuel electrode side were studied. Here, the flow rate of hydrogen peroxide was adjusted so that the open circuit voltage was approximately 500 mV at each temperature.

In this test, the relationship between the derived current density and the operating voltage is shown in FIG. 40 .

If the temperature is 70-90°C, the relationship between the drop of operating voltage and the increase of current density is basically the same. When the temperature drops to 30°C, the operating voltage drops sharply, and the dischargeable limit current density is observed to drop.

In FIG. 41, the results of FIG. 40 are summarized as a relationship between the operating voltage and the hydrogen generation rate.

From this, it can be seen that the hydrogen generation rate tends to depend on the operating voltage, and hydrogen is generated at 300 to 500 mV. In addition, hydrogen is most likely to be generated at a temperature of 90°C, and it has been observed that hydrogen is not generated unless the operating voltage is increased when the temperature is low.

The point here is to lead out the current from the hydrogen production cell to the outside in the above-mentioned Example 2. In other words, the hydrogen production cell of Example 2 converts a part of the fuel into hydrogen while exporting electric energy to the outside. In addition, it is reforming at an astonishingly low temperature of 30 to 90°C, and it is considered to be a completely new hydrogen production device that has never existed before, and the effect of using this hydrogen production device in a hydrogen supply system is remarkable.

Example 3

The following shows an example of a state in which hydrogen is produced by the hydrogen production device (charging condition) used in the hydrogen supply system of the invention according to claim 5 of the present application.

Hydrogen production example 3-1

Fig. 42 schematically shows 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 is the same as that of the hydrogen production example 1-1, except that the fuel electrode is used as the cathode and the above-mentioned oxidized electrode is used as the anode, and a device for applying electric energy from the outside is provided.

The hydrogen production cell is set in a hot air circulation type electric furnace, and at a cell temperature (operating temperature) of 50°C, air flows at a flow rate of 10 to 80 ml/min on the air electrode side, and at a flow rate of 5 ml/min on the fuel electrode side. Flowing 1M methanol aqueous solution (fuel), at this time, the current flowing between the air electrode and the fuel electrode is changed by using a DC power supply from the outside, and 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 was studied. Here, the ratio of the chemical energy of generated hydrogen to the input electrical energy is set as the energy efficiency of the charging condition. In addition, 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.

Calculation formula:

Energy efficiency (%)=(heat of combustion of _H2 /applied electric energy)×100

Heat of combustion (KJ) of _H2 generated within 1 minute = ( _H2 generation rate ml/min/24.47/1000)×286KJ/mol[HHV]

Electric energy applied within 1 minute (KJ) = [voltage mV/1000×current A×60sec]Wsec/1000

Here, it is described for the sake of caution, but the purpose of the present invention is to obtain hydrogen gas whose chemical energy is greater than or equal to the input electric energy. This does not mean that the principle of energy conservation determined by thermodynamics is ignored. On the whole, since part of the organic fuel is oxidized, if the input electric energy includes the chemical energy consumed by the oxidation of the organic fuel, it is less than or equal to 100%. In the present invention, in order to clarify the energy efficiency, which is different from the conventional water electrolysis to produce hydrogen, the ratio of the chemical energy of 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 .

Under the condition that the current density is less than or equal to 40mA/cm ² , the hydrogen production efficiency (electricity efficiency of hydrogen production) exists in a region greater than or equal to 100% (a dotted line in FIG. 43 indicates the line where the hydrogen production efficiency is 100%). Regional operation can obtain hydrogen greater than or equal to the input electric energy.

In FIG. 44, the results of FIG. 43 are summarized as a relationship between the operating voltage and the hydrogen generation rate.

It can be seen from this that the hydrogen generation rate (hydrogen generation amount) tends to depend on the operating voltage. Hydrogen is generated when the operating voltage is 400 mV or higher, and the hydrogen generation rate is basically constant when the operating voltage is 600 mV or higher. When the air flow rate is small, the hydrogen generation rate is high. (easy to produce hydrogen).

The relationship between the applied current density and the operating voltage is shown in Fig. 45 .

The region where the hydrogen production efficiency is equal to or greater than 100% confirmed in FIG. 43 is an operating voltage equal to or less than 600 mV in FIG. 45 .

In addition, the relationship between the operating voltage and the energy efficiency is shown in FIG. 46 .

It can be seen that even if the operating voltage is around 1000mV, the energy efficiency is greater than or equal to 100%, especially when the operating voltage is less than or equal to 600mV and the air flow rate is 30-50ml/min, the energy efficiency is high.

Next, gas is generated under the conditions of high energy efficiency (1050%), temperature 50°C, fuel flow rate 5ml/min, air flow rate 50ml/min, and current density 4.8mA/ ^cm2 , and the hydrogen concentration in the gas is measured by gas chromatography . As a result, the generated gas contained about 86% of hydrogen, and the hydrogen generation rate was 7.8 ml/min. In addition, CO was not detected.

Hydrogen production example 3-2

Use the same hydrogen production cell as in Hydrogen Production Example 3-1, at a cell temperature of 30°C, flow air at a flow rate of 10 to 70 ml/min on the air electrode side, and flow 1M methanol at a flow rate of 5 ml/min at the fuel electrode side Aqueous solution (fuel), at this time, the current flowing between the air electrode and the fuel electrode is changed by using a direct current power supply from the outside, and the operating voltage of the fuel electrode and the air electrode, the generation rate of hydrogen generated on the fuel electrode side, and the energy efficiency are checked. studied.

In this test, the relationship between the applied current density and the hydrogen production rate is shown in FIG. 47 , and the relationship between the operating voltage and the hydrogen production rate is shown in FIG. 48 .

From this, it can be seen that the hydrogen generation rate (the amount of hydrogen generation) tends to depend on the operating voltage, and that hydrogen gas is generated when the operating voltage is 400 mV or higher, and hydrogen tends to be generated when the air flow rate is small. When the air flow rate is 10ml/min, the hydrogen generation rate is basically constant when the air flow rate is ≥ 600mV; when the air flow rate is 30ml/min, it shows an increasing tendency when the air flow rate is greater than or equal to 800mV; In this case, hydrogen will not be produced unless the operating voltage is increased.

In addition, the relationship between the operating voltage and the energy efficiency is shown in FIG. 49 .

It can be seen that even if the operating voltage is around 1000mV, the energy efficiency is greater than or equal to 100%, especially when the operating voltage is less than or equal to 600mV and the air flow rate is 30ml/min, the energy efficiency is high.

Hydrogen production example 3-3

The test was conducted under the same conditions as in Hydrogen Production Example 3-2 except that the cell temperature was 70°C, and the operating voltages of the fuel electrode and the air electrode, the hydrogen generation rate at the fuel electrode side, and energy efficiency were investigated.

In this test, the relationship between the applied current density and the hydrogen production rate is shown in FIG. 50 , and the relationship between the operating voltage and the hydrogen production rate is shown in FIG. 51 .

From this, it can be seen that the hydrogen generation rate tends to depend on the operating voltage, and that hydrogen is generated at an operating voltage of 400 mV or higher, and hydrogen tends to be generated when the air flow rate is small. When the air flow rate is 10ml/min, the hydrogen generation rate is basically constant when the air flow rate is ≥ 600mV; when the air flow rate is 30ml/min, it shows an increasing tendency when the air flow rate is greater than or equal to 800mV; In this case, hydrogen will not be produced unless the operating voltage is increased.

In addition, the relationship between the operating voltage and the energy efficiency is shown in FIG. 52 .

It can be seen that even if the operating voltage is around 1000mV, the energy efficiency is greater than or equal to 100%, especially when the operating voltage is less than or equal to 600mV and the air flow rate is 10-30ml/min, the energy efficiency is high.

Hydrogen production example 3-4

Using the same hydrogen production cell as in Hydrogen Production Example 3-1, at a cell temperature of 90°C, flow air at a flow rate of 10 to 200 ml/min on the air electrode side, and flow 1M hydrogen at a flow rate of 5 ml/min at the fuel electrode side. Methanol aqueous solution (fuel), at this time, the current flowing between the air electrode and the fuel electrode is changed by using a DC power supply from the outside, and the operating voltage of the fuel electrode and the air electrode, the generation rate of hydrogen generated on the fuel electrode side, and the energy efficiency Were studied.

In this test, the relationship between the applied current density and the hydrogen production rate is shown in FIG. 53 , and the relationship between the operating voltage and the hydrogen production rate is shown in FIG. 54 .

It can be seen from this that the hydrogen generation rate tends to depend on the operating voltage. When the operating voltage is 300mV or higher, hydrogen is generated, and the air flow rate is small. When the air flow rate is 10ml/min, hydrogen is generated at 500mV or higher. The speed is basically constant. When the air flow rate is 50-100ml/min, it shows an increasing tendency when it is greater than or equal to 800mV. When the air flow rate is 200ml/min, if it is not greater than or equal to 800mV, hydrogen will not be generated.

In addition, the relationship between the operating voltage and the energy efficiency is shown in FIG. 55 .

It can be seen that even if the operating voltage is around 1000mV, the energy efficiency is greater than or equal to 100%, especially when the operating voltage is less than or equal to 500mV and the air flow rate is 50ml/min, the energy efficiency is high.

Next, the relationship between the applied current density and the hydrogen generation rate at each temperature of hydrogen production examples 3-1 to 3-4 when the air flow rate is 50 ml/min is shown in FIG. 56, and the relationship between the operating voltage and the hydrogen generation rate is shown in FIG. in Figure 57.

From this, it can be seen that the hydrogen generation rate tends to be dependent on temperature, and when the operating temperature is high, hydrogen is generated at a low operating voltage, and the hydrogen generation rate is also high.

In addition, the relationship between the operating voltage and the energy efficiency is shown in FIG. 58 .

It can be seen that even if the operating voltage is around 1000mV, the energy efficiency is greater than or equal to 100%, especially when the operating voltage is less than or equal to 600mV, the energy efficiency is high.

Hydrogen production example 3-5

Use the same hydrogen production cell as in Hydrogen Production Example 3-1, at a cell temperature of 50°C, flow air at a flow rate of 50ml/min on the air electrode side, and change the fuel flow rate on the fuel electrode side to 1.5, 2.5, 5.0, 7.5 , 10.0ml/min, under this condition, at this time, the current flowing between the air electrode and the fuel electrode is changed by using an external DC power supply, and at the same time, the operating voltage of the fuel electrode and the air electrode, and the hydrogen generated on the fuel electrode side The generation speed and energy efficiency were studied.

In this test, the relationship between the applied current density and the hydrogen production rate is shown in FIG. 59 , and the relationship between the operating voltage and the hydrogen production rate is shown in FIG. 60 .

It can be seen from this that the hydrogen generation rate tends to depend on the operating voltage. Hydrogen is generated when the operating voltage is 400 mV or higher, and hydrogen is easy to generate when the fuel flow rate is large. For any fuel flow rate, it is observed that hydrogen Spawn speed tends to increase.

In addition, the relationship between the operating voltage and the energy efficiency is shown in FIG. 61 .

It can be seen that for any fuel flow rate, even if the operating voltage is around 1000mV, the energy efficiency is greater than or equal to 100%, especially when the operating voltage is less than or equal to 600mV, the energy efficiency is high.

Hydrogen Production Example 3-6

Use the same hydrogen production cell as in Hydrogen Production Example 3-1, at a cell temperature of 50°C, flow air at a flow rate of 50ml/min on the air electrode side, and a constant flow rate of 5ml/min fuel at the fuel electrode side, and change the fuel The concentration is 0.5, 1, 2, 3M. Under these conditions, at this time, the current flowing between the air electrode and the fuel electrode is changed by using a DC power supply from the outside. At the same time, the operating voltage of the fuel electrode and the air electrode is The generation rate and energy efficiency of the produced hydrogen were studied.

In this test, the relationship between the applied current density and the hydrogen production rate is shown in FIG. 62 , and the relationship between the operating voltage and the hydrogen production rate is shown in FIG. 63 .

It can be seen that, for any fuel concentration, the applied current density is basically proportional to the hydrogen generation rate in the region greater than or equal to 0.02A/cm ² .

In addition, the hydrogen generation rate tends to depend on the operating voltage. Hydrogen is generated at an operating voltage of 400 mV or higher, and when the fuel concentration is high, hydrogen is likely to be generated even at a low operating voltage. For the fuel concentration of 2M and 3M, the hydrogen generation rate increases sharply at 400-500mV; when the fuel concentration is 1M, the hydrogen generation rate is basically constant at 400-800mV, and it shows an increase when it is greater than or equal to 800mV. Tendency: In the case of lower fuel concentration, hydrogen will not be generated unless the operating voltage is increased.

In addition, the relationship between the operating voltage and the energy efficiency is shown in FIG. 64 .

It can be known that, except for the case where the fuel concentration is 0.5M, even if the operating voltage is around 1000mV, the energy efficiency is greater than or equal to 100%, especially when the operating voltage is less than or equal to 600mV, when the fuel concentration is 1, 2, 3M, the energy efficiency high. In addition, when the fuel concentration is 0.5M, since hydrogen is not generated in the low voltage region, the performance of energy efficiency is completely different from that of other conditions.

Hydrogen Production Example 3-7

Use the same hydrogen production cell as in Hydrogen Production Example 3-1 (but the air electrode forms the oxidation electrode of the flowing oxidizing gas), at a cell temperature of 50°C, the fuel with a concentration of 1M on the fuel electrode side is a constant flow rate of 5ml/min, On the oxidation electrode side, the flow rate of the oxidizing gas is 14.0ml/min, and the oxygen concentration is changed to 10, 21, 40, 100%. At the same time, the operating voltage of the fuel electrode and the oxidation electrode, the generation rate of hydrogen generated on the fuel electrode side, and the energy efficiency were studied. Here, air is used for the gas with an oxygen concentration of 21%, nitrogen gas is mixed with air for a gas with an oxygen concentration of 10%, and oxygen (100% oxygen concentration) is prepared for a gas with an oxygen concentration of 40%.

In this test, the relationship between the applied current density and the hydrogen production rate is shown in FIG. 65 , and the relationship between the operating voltage and the hydrogen production rate is shown in FIG. 66 .

It can be seen that, for any oxygen concentration, the applied current density is basically proportional to the hydrogen generation rate in the region greater than or equal to 0.03A/cm ² .

In addition, the hydrogen generation rate tends to depend on the operating voltage. When the operating voltage is 400mV or more, hydrogen is generated. When the oxygen concentration is high, hydrogen is easy to generate even if the operating voltage is low. The hydrogen generation rate is basically constant at 400-800mV. It shows a tendency to increase at 800 mV or more.

In addition, the relationship between the operating voltage and the energy efficiency is shown in FIG. 67 .

It can be seen that even when the applied voltage is around 1000mV, the energy efficiency is equal to or greater than 100%, especially when the applied voltage is equal to or less than 600mV and the oxygen concentration is high, the energy efficiency is high.

Hydrogen Production Example 3-8

Use the same hydrogen production cell as in Hydrogen Production Example 3-1 (but the air electrode forms the oxidation electrode of flowing liquid hydrogen peroxide), set the hydrogen production cell in a hot air circulation type electric furnace, and the battery temperature is 30°C, 50°C, At 70°C and 90°C, flow 1M methanol aqueous solution (fuel ₎ at a flow rate of 5ml/min on the fuel electrode side, and flow 1M _H2O2 (hydrogen peroxide) at a flow rate of 2.6-5.5ml/min at the oxidation electrode side ), at this time, the current flowing between the oxide electrode and the fuel electrode was changed using an external DC power supply, and the operating voltage of the fuel electrode and the oxide electrode, the generation rate of hydrogen generated on the fuel electrode side, and the energy efficiency were studied.

Here, the flow rate of hydrogen peroxide was adjusted so that the open circuit voltage was basically 500 mV at each temperature.

In this test, the relationship between the applied current density and the hydrogen production rate is shown in FIG. 68 , and the relationship between the operating voltage and the hydrogen production rate is shown in FIG. 69 .

From this, it can be seen that the hydrogen generation rate tends to depend on the operating voltage. Hydrogen is generated when the operating voltage is 500 mV or higher, and tends to increase when the operating voltage is 800 mV or higher. Hydrogen is easily generated when the operating temperature is high.

In addition, the relationship between the operating voltage and the energy efficiency is shown in FIG. 70 .

It can be seen that even if the operating voltage is around 1000mV, the energy efficiency is greater than or equal to 100%, especially when the operating voltage is less than or equal to 800mV and the temperature is 90°C, the energy efficiency is high.

The important point here is that in the above-mentioned Example 3, hydrogen is obtained at a current greater than or equal to the current applied to the hydrogen production cell from the outside. In other words, with the hydrogen production cell of Example 3, hydrogen with an energy equal to or greater than the applied electric energy is produced. In addition, it is reforming at an astonishingly low temperature of 30 to 90°C, and it is considered to be a completely new hydrogen production device that has never existed before. Therefore, by using such a hydrogen production device in a hydrogen supply system, significant Effect.

Examples of hydrogen production by the hydrogen production device used in the hydrogen supply system of the present invention using fuels other than methanol are shown in the following examples.

Example 4

Using ethanol as fuel, hydrogen is produced by the hydrogen production device (open circuit condition) used in the hydrogen production system of the invention according to claim 3 of the present application.

Use the same hydrogen production cell as in Hydrogen Production Example 1-1. The temperature of the cell is 80°C. The fuel electrode side flows through the ethanol solution with a concentration of 1M at a flow rate of 5ml/min, and the air electrode side flows through it at a flow rate of 65ml/min. Through the air, the open circuit voltage of the battery and the generation rate of gas generated on the fuel electrode side were measured. The hydrogen concentration in the generated gas was analyzed by gas chromatography to determine the hydrogen generation rate.

The results are shown in Table 1.

Table 1

Air (ml/min) Open circuit voltage (mV) Gas generation rate (ml/min) H₂ concentration (%) H₂ generation rate (ml/min) 65 478 0.6 65.2 0.39

As shown in Table 1, it was confirmed that hydrogen was generated at an open circuit voltage of 478 mV, but the hydrogen generation rate was low.

Example 5

Using ethylene glycol as fuel, hydrogen is produced by the hydrogen production device (open circuit condition) used in the hydrogen production system of the invention according to claim 3 of the present application.

Use the same hydrogen production cell as in Hydrogen Production Example 1-1, the cell temperature is 80°C, the fuel electrode side flows through the ethylene glycol aqueous solution with a concentration of 1M at a flow rate of 5ml/min, and the air electrode side flows at a flow rate of 105ml/min. The flow rate is passed through the air, and the open circuit voltage of the battery and the generation rate of the gas generated on the fuel electrode side are measured. The hydrogen concentration in the generated gas was analyzed by gas chromatography to determine the hydrogen generation rate.

The results are shown in Table 2.

Table 2

Air (ml/min) Open circuit voltage (mV) Gas generation rate (ml/min) H₂ concentration (%) H₂ generation rate (ml/min) 105 474 2.4 88.4 2.12

As shown in Table 2, at an open circuit voltage of 474 mV, hydrogen was confirmed to be generated, and the hydrogen generation rate was higher than when ethanol aqueous solution was used as fuel, but lower than that when methanol aqueous solution was used.

Example 6

Using isopropanol as a fuel, hydrogen is produced by the hydrogen production device (open circuit condition) used in the hydrogen production system of the invention according to claim 3 of the present application.

Use the same hydrogen production cell as in Hydrogen Production Example 1-1. The temperature of the cell is 80°C. The fuel electrode side flows through a 1M isopropanol aqueous solution at a flow rate of 5ml/min, and the air electrode side flows at a flow rate of 35ml/min. The flow rate is passed through the air, and the open circuit voltage of the battery and the generation rate of the gas generated on the fuel electrode side are measured. The hydrogen concentration in the generated gas was analyzed by gas chromatography to determine the hydrogen generation rate.

The results are shown in Table 3.

table 3

Air (ml/min) Open circuit voltage (mV) Gas generation rate (ml/min) H₂ concentration (%) H₂ generation rate (ml/min) 35 514 3.96 95.6 3.78

As shown in Table 3, when the open circuit voltage was 514mV, hydrogen was confirmed to be generated, and the hydrogen generation rate was higher than when ethanol aqueous solution or ethylene glycol aqueous solution was used as fuel, and was closest to the case of methanol aqueous solution. In particular, the concentration of hydrogen in the produced gas is extremely high.

Example 7

Using diethyl ether as a fuel, hydrogen is produced by the hydrogen production device (open circuit condition) used in the hydrogen production system of the invention according to claim 3 of the present application.

Use the same hydrogen production cell as in Hydrogen Production Example 1-1, the cell temperature is 80°C, the fuel electrode side flows through a diethyl ether solution with a concentration of 1M at a flow rate of 5ml/min, and the air electrode side flows at a flow rate of 20ml/min The open circuit voltage of the battery and the generation rate of gas generated on the fuel electrode side were measured by flowing air. The hydrogen concentration in the generated gas was analyzed by gas chromatography to determine the hydrogen generation rate.

The results are shown in Table 4.

Table 4

Air (ml/min) Open circuit voltage (mV) Gas generation rate (ml/min) H₂ concentration (%) H₂ generation rate (ml/min) 20 565 3.0 7.6 0.23

As shown in Table 4, it was confirmed that hydrogen was generated at an open circuit voltage of 565 mV, and the hydrogen concentration in the generated gas was lower than when alcohol was used as fuel, and the hydrogen generation rate was also lower.

Example 8

Using formaldehyde and formic acid as fuel, hydrogen is produced by the hydrogen production device (open circuit condition) used in the hydrogen production system of the invention according to claim 3 of the present application.

Use the same hydrogen production cell as in Hydrogen Production Example 1-1. The temperature of the cell is 50°C. The fuel electrode side flows through the formaldehyde solution with a concentration of 1M and the formic acid solution with a concentration of 1M respectively at a flow rate of 5ml/min. Air was flowed through the side at a flow rate of 0 to 100 ml/min, and the open circuit voltage of the battery and the generation rate of gas generated at the fuel electrode side were measured. The hydrogen concentration in the generated gas was analyzed by gas chromatography to determine the hydrogen generation rate.

The measurement results are shown in Figs. 71 and 72 together with the case of using methanol.

As shown in FIG. 71 , using formaldehyde and formic acid, it was confirmed that hydrogen was generated on the fuel electrode side of the battery by reducing the air flow rate in the same manner as methanol was used. In addition, the hydrogen generation rate is highest with methanol, followed by formaldehyde and formic acid, and in this order, if the air flow rate is not reduced, hydrogen will not be generated.

As can be seen from FIG. 72 , when formaldehyde and formic acid are used, the hydrogen generation rate (hydrogen generation amount) tends to depend on the open circuit voltage as in methanol, and hydrogen gas is found to be generated at an open circuit voltage of 200 to 800 mV. In addition, when formic acid is used, hydrogen is generated at a lower open circuit voltage than methanol and formaldehyde, and the peak value of the hydrogen generation rate is about 500 mV compared to methanol and formaldehyde, while for formic acid, the open circuit voltage is lower (350 mV).

Possibility of industrial use

As described above, the hydrogen supply system of the present invention uses a hydrogen production device that can decompose fuel containing organic matter at 100°C or less to produce hydrogen-containing gas, so it can be used as a hydrogen supply system for mounting on fuel cell vehicles. Hydrogen storage tanks, hydrogen storage tanks for supplying hydrogen to fuel cell vehicles. In addition, it can also be used in a hydrogen supply system when hydrogen is used as a process gas in the manufacture of semiconductor devices.

Claims (47)

1. A hydrogen supply system, characterized in that it has at least a hydrogen supply device for supplying hydrogen to a hydrogen storage device and a hydrogen production device for producing a hydrogen-containing gas for supplying the hydrogen supply device; A hydrogen production device for producing a hydrogen-containing gas from an organic fuel, the hydrogen production device has a diaphragm, a fuel electrode provided on one surface of the diaphragm, a device for supplying fuel containing organic matter and water to the fuel electrode, and An oxide electrode on the other side of the separator, means for supplying an oxidant to the oxide electrode, and means for generating and discharging hydrogen-containing gas from the fuel electrode side. 2. The hydrogen supply system according to claim 1, wherein the hydrogen storage device is a hydrogen storage container mounted on a fuel cell vehicle. 3. The hydrogen supply system according to claim 1, wherein the hydrogen production device does not have a device for deriving electric energy from the hydrogen production cell constituting the hydrogen production device to the outside, and the hydrogen production cell is supplied with electricity from the outside. The open circuit state of the device for electrical energy. 4 . The hydrogen supply system according to claim 1 , wherein the hydrogen production device has a device for exporting electric energy to the outside by using the fuel pole as a negative pole and the oxide pole as a positive pole. 5 . The hydrogen supply system according to claim 1 , wherein the hydrogen production device has means for applying electric energy from the outside by using the fuel electrode as a cathode and the oxide electrode as an anode. 6. The hydrogen supply system according to claim 1, wherein two or more hydrogen production devices selected from the following hydrogen production devices are used in combination: An open-circuit hydrogen production device of a device for deriving electric energy to the outside and a device for applying electric energy to the hydrogen production cell from the outside; a hydrogen with a device for deriving electric energy to the outside with the fuel as the negative pole and the oxide as the positive pole A production device; and a hydrogen production device which uses the fuel electrode as a cathode and the oxide electrode as an anode, and has means for applying electric energy from the outside. 7. The hydrogen supply system according to claim 1, wherein in the hydrogen production device, the voltage between the fuel electrode and the oxidation electrode is 200 to 1000 mV. 8. The hydrogen supply system according to claim 3, wherein in the hydrogen production device, the voltage between the fuel electrode and the oxidation electrode is 300 to 800 mV. 9. The hydrogen supply system according to claim 4, wherein in the hydrogen production device, the voltage between the fuel electrode and the oxidation electrode is 200 to 600 mV. 10. The hydrogen supply system according to claim 4, characterized in that, in the hydrogen production device, the voltage between the fuel electrode and the oxidation electrode and/or the The amount of hydrogen-containing gas produced. 11. The hydrogen supply system according to claim 5, wherein in the hydrogen production device, a voltage between the fuel electrode and the oxidation electrode is 300 to 1000 mV. 12. The hydrogen supply system according to claim 5, wherein in the hydrogen production device, the voltage between the fuel electrode and the oxidation electrode and/or the voltage between the fuel electrode and the oxidation electrode are adjusted by adjusting the applied electric energy. The amount of hydrogen-containing gas produced. 13. The hydrogen supply system according to any one of claims 1 to 12, wherein in the hydrogen production device, the voltage between the fuel electrode and the oxidation electrode is adjusted to adjust the The amount of hydrogen-containing gas produced. 14. The hydrogen supply system according to any one of claims 1 to 12, wherein in the hydrogen production device, the fuel electrode and the oxidizer are adjusted by adjusting the supply amount of the oxidizer. The voltage between the poles and/or the amount of hydrogen-containing gas generated. 15. The hydrogen supply system according to claim 13, wherein in the hydrogen production device, the voltage between the fuel electrode and the oxidation electrode is adjusted by adjusting the supply amount of the oxidant and/or Or the generation amount of the hydrogen-containing gas. 16. The hydrogen supply system according to any one of claims 1 to 12, wherein in the hydrogen production device, the fuel electrode and the oxidation electrode are adjusted by adjusting the concentration of the oxidant The voltage between and/or the amount of generation of the hydrogen-containing gas. 17. The hydrogen supply system according to claim 13, characterized in that, in the hydrogen production device, the voltage and/or the voltage between the fuel electrode and the oxidation electrode is adjusted by adjusting the concentration of the oxidant The generation amount of the hydrogen-containing gas. 18. The hydrogen supply system according to claim 14, characterized in that, in the hydrogen production device, the voltage and/or the voltage between the fuel electrode and the oxidation electrode is adjusted by adjusting the concentration of the oxidant The generation amount of the hydrogen-containing gas. 19. The hydrogen supply system according to any one of claims 1 to 12, wherein in the hydrogen production device, the fuel is adjusted by adjusting the supply amount of the fuel containing organic matter and water. The voltage between the electrode and the oxide electrode and/or the generation amount of the hydrogen-containing gas. 20. The hydrogen supply system according to claim 13, wherein, in the hydrogen production device, the ratio between the fuel electrode and the oxidation electrode is adjusted by adjusting the supply amount of the fuel containing organic matter and water. The voltage between and/or the generation amount of the hydrogen-containing gas. 21. The hydrogen supply system according to claim 14, wherein in the hydrogen production device, the ratio between the fuel electrode and the oxidation electrode is adjusted by adjusting the supply amount of the fuel containing organic matter and water. The voltage between and/or the generation amount of the hydrogen-containing gas. 22. The hydrogen supply system according to claim 16, wherein in the hydrogen production device, the ratio between the fuel electrode and the oxidation electrode is adjusted by adjusting the supply amount of the fuel containing organic matter and water. The voltage between and/or the generation amount of the hydrogen-containing gas. 23. The hydrogen supply system according to any one of claims 1 to 12, wherein in the hydrogen production device, the fuel electrode is adjusted by adjusting the concentration of the fuel containing organic matter and water. and the voltage between the oxide electrode and/or the generation amount of the hydrogen-containing gas. 24. The hydrogen supply system according to claim 13, wherein in the hydrogen production device, the concentration between the fuel electrode and the oxidation electrode is adjusted by adjusting the concentration of the fuel containing organic matter and water. The voltage and/or the generation amount of the hydrogen-containing gas. 25. The hydrogen supply system according to claim 14, wherein in the hydrogen production device, the concentration between the fuel electrode and the oxidation electrode is adjusted by adjusting the concentration of the fuel containing organic matter and water. The voltage and/or the generation amount of the hydrogen-containing gas. 26. The hydrogen supply system according to claim 16, wherein in the hydrogen production device, the concentration between the fuel electrode and the oxidation electrode is adjusted by adjusting the concentration of the fuel containing organic matter and water. The voltage and/or the generation amount of the hydrogen-containing gas. 27. The hydrogen supply system according to claim 19, wherein in the hydrogen production device, the concentration between the fuel electrode and the oxidation electrode is adjusted by adjusting the concentration of the fuel containing organic matter and water. The voltage and/or the generation amount of the hydrogen-containing gas. 28. The hydrogen supply system according to any one of claims 1 to 12, wherein the operating temperature of the hydrogen production device is 100°C or less. 29. The hydrogen supply system according to claim 28, wherein the operating temperature is 30-90°C. 30. The hydrogen supply system according to claim 13, wherein the operating temperature of the hydrogen production device is 100°C or less. 31. The hydrogen supply system according to claim 14, wherein the operating temperature of the hydrogen production device is 100°C or less. 32. The hydrogen supply system according to claim 16, wherein the operating temperature of the hydrogen production device is 100°C or less. 33. The hydrogen supply system according to claim 19, wherein the operating temperature of the hydrogen production device is 100°C or less. 34. The hydrogen supply system according to claim 23, wherein the operating temperature of the hydrogen production device is 100°C or less. 35. The hydrogen supply system according to any one of claims 1 to 12, wherein the organic substance supplied to the fuel electrode of the hydrogen production device is selected from alcohols, aldehydes, carboxylic acids, and ethers One or two or more organic substances. 36. The hydrogen supply system of claim 35, wherein the alcohol is methanol. 37. The hydrogen supply system according to any one of claims 1 to 12, wherein the oxidizing agent supplied to the oxidation electrode of the hydrogen production device is an oxygen-containing gas or oxygen. 38. The hydrogen supply system according to claim 6, wherein the oxidizing agent supplied to the oxidation electrode of the one hydrogen production device is exhaust air discharged from the other hydrogen production device. 39. The hydrogen supply system according to any one of claims 1 to 12, wherein the oxidizing agent supplied to the oxidation electrode of the hydrogen production device is a liquid containing hydrogen peroxide. 40. The hydrogen supply system according to any one of claims 1 to 12, wherein the diaphragm of the hydrogen production device is a proton conductive solid electrolyte membrane. 41. The hydrogen supply system according to claim 40, wherein the proton conductive solid electrolyte membrane is a perfluorocarbon sulfonic acid solid electrolyte membrane. 42. The hydrogen supply system according to any one of claims 1 to 12, wherein the catalyst of the fuel electrode of the hydrogen production device is a catalyst in which a Pt-Ru alloy is supported on carbon powder. 43. The hydrogen supply system according to any one of claims 1 to 12, wherein the catalyst of the oxidation electrode of the hydrogen production device is a catalyst in which Pt is supported on carbon powder. 44. The hydrogen supply system according to any one of claims 1 to 12, wherein a circulation device for the fuel containing organic matter and water is installed on the hydrogen production device. 45. The hydrogen supply system according to any one of claims 1 to 12, wherein a carbon dioxide absorption unit for absorbing carbon dioxide contained in the hydrogen-containing gas is provided on the hydrogen production device. 46. The hydrogen supply system according to any one of claims 1 to 12, wherein a hydrogen permeable membrane is provided at an outlet of the hydrogen-containing gas of the hydrogen production device. 47. The hydrogen supply system according to any one of claims 1 to 12, characterized in that no heat insulating material for blocking the heat emitted by the hydrogen production device is provided.

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