JP2005298300A - Hydrogen reformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen reforming device where hydrogen generation can be precisely controlled and miniaturization can be certainly promoted. <P>SOLUTION: A catalyst supporting part 4 is moved vertically and directly by a moving part 6 being physically connected to it. A catalyst 5 is in contact with a hydrogen liquid fuel 7 and then a catalytic reaction is caused. Therefore the contacting area of the catalyst 5 with the hydrogen liquid fuel 7 can be certainly controlled by its moving distance and then the amount of generated hydrogen is precisely controlled. As an additional mechanism to regulate the supplying amount of a reaction object is not necessary, the hydrogen reforming device 1 being easy to be handled can be obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydrogen reformer that generates hydrogen by bringing a catalyst into contact with hydrogen liquid fuel.

  As an example of using hydrogen, a fuel cell supplies fuel (hydrogen) and air (oxygen) from the outside continuously to separate electrodes, and uses a catalyst containing these in an electrochemical cell. To extract electric energy. Among them, those using polymer solid electrolyte membranes are expected because they can operate at low temperatures and can be miniaturized.

  Originally, in such a fuel cell, it is preferable to supply hydrogen directly to the electrode, but there is a problem that gaseous hydrogen is troublesome to handle and requires a high-pressure vessel. Accordingly, a direct methanol fuel cell (DMFC), in which liquid methanol is supplied as fuel and hydrogen is generated by a catalyst in an electrode, has become the mainstream. Since this system uses liquid methanol as fuel, fuel can be replenished with a small fuel cartridge, and the system can be made compact and easy to handle. However, there is a phenomenon that methanol permeates through the polymer solid electrolyte membrane (crossover phenomenon), and there is a problem that the power generation capacity is reduced to 20 to 30% as compared with a fuel cell that directly supplies hydrogen.

An apparatus capable of supplying hydrogen as needed is desired in various fields, without being limited to the fuel cell example described above. Among them, an apparatus for generating gaseous hydrogen by reforming liquid fuel as necessary has been devised.
For example, an apparatus that generates hydrogen by adjusting the supply amount of Mg particles dropped into water in a container containing water is known (see, for example, Patent Document 1).
Also, an apparatus for generating hydrogen by positioning a solid catalyst below the inside of the container and adjusting the supply amount of the alkaline aqueous solution of the metal hydride complex to be dropped is known (for example, see Patent Document 2). ).
Furthermore, an apparatus is known in which a liquid metal hydride complex compound is injected into a container while adjusting the supply amount by a pump, and reacted with a catalyst provided in the container to generate hydrogen (for example, a patent) Reference 3).

Japanese Patent Laying-Open No. 2003-292302 (first and second pages, FIG. 1) JP 2003-146605 A (2nd to 3rd pages, FIG. 1) JP 2002-29702 A (2nd to 3rd pages, FIG. 1)

  By the way, in each of the above documents, the hydrogen generation amount is adjusted by adjusting the supply amount of the reaction object necessary for the hydrogen generation reaction. However, since these reaction objects are aggregates of particles and powders and fluids such as liquids, it is difficult to accurately control the supply amount, and the amount of hydrogen generation cannot be precisely adjusted. is there. In particular, Patent Document 3 requires a pump for injecting a liquid into a container, and there is a problem that it is difficult to reduce the size of the apparatus.

  An object of the present invention is to provide a small-sized hydrogen reforming apparatus that can precisely control the amount of generated hydrogen.

  The hydrogen reforming apparatus of the present invention includes a hydrogen liquid fuel storage unit, a catalyst holding unit that is provided so as to be immersed in the hydrogen liquid fuel in the hydrogen liquid fuel storage unit, and holds the catalyst, the hydrogen liquid fuel, and the catalyst. It is characterized by comprising a detecting means for detecting the amount of hydrogen generated by the reaction, and a controller for adjusting the amount of immersion of the catalyst holding part according to the detection result of the detecting means.

  According to this invention, since the catalyst holding part holding the catalyst moves directly and is immersed in the hydrogen liquid fuel and reacts, the hydrogen liquid can be controlled by controlling the amount of immersion according to the amount of hydrogen generated. The contact area between the fuel and the catalyst is reliably adjusted, and the amount of hydrogen generation is precisely controlled. In addition, since there is no need for an incidental mechanism for adjusting the supply amount of the reaction object, a small hydrogen reformer can be obtained.

In the present invention, a configuration in which the catalyst holding part moves on a substantially straight line is preferable.
In this invention, since the catalyst holding part moves in a substantially straight line, the moving mechanism is simplified and the size can be further reduced. Therefore, the overall apparatus is also small.

In the present invention, the detection means is preferably a pressure sensor.
In the present invention, since the detection means is a pressure sensor, it is possible to precisely control the amount of hydrogen generated according to the pressure in the hydrogen reforming apparatus. Moreover, if the pressure is set to a necessary minimum appropriate pressure, the pressure-resistant structure is not necessary, and the entire apparatus is reduced in size.

In the present invention, a configuration in which the hydrogen liquid fuel storage section is detachable is preferable.
In this invention, since the hydrogen liquid fuel storage part is detachable, the spent fuel can be replenished and replaced for each container as the hydrogen liquid fuel storage part, and the operation of supply mechanisms such as valves and pumps becomes unnecessary. , Handling becomes simple.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall conceptual diagram of the hydrogen reforming apparatus 1 according to this embodiment in a state where hydrogen is not generated, and FIG. 2 shows an overall conceptual diagram of a state where hydrogen is generated.

  In FIG. 1, a hydrogen reformer 1 generates hydrogen to be supplied to a fuel cell 13 by a reaction between a hydrogen liquid fuel 7 and a catalyst 5, and the hydrogen liquid fuel in which the hydrogen liquid fuel 7 is stored. The storage unit 3 and the hydrogen storage unit 2 in which the generated hydrogen is temporarily stored are provided, and the hydrogen liquid fuel storage unit 3 can be detached from the hydrogen storage unit 2 by using the stopper 14. Is provided. A packing 15 is provided at the two connection portions so that generated hydrogen does not leak. The structure of these main components may be a structure that can withstand several atmospheric pressures.

  Here, as the hydrogen liquid fuel 7, an alkaline aqueous solution of a hydrocarbon such as methanol, cyclohexane or decalin, or a metal hydride complex compound such as sodium borohydride or lithium aluminum hydride can be used.

  Inside a space formed by connecting the hydrogen storage unit 2 and the hydrogen liquid fuel storage unit 3, a catalyst holding unit 4 holding the catalyst 5 is provided. The catalyst holding unit 4 is connected to a movable unit 6 that moves up and down, and moves linearly between the hydrogen storage unit 2 and the hydrogen liquid fuel storage unit 3 as shown by the arrows in FIG. The liquid fuel 7 can be immersed freely. Here, the sliding portion between the movable portion 6 and the hydrogen storage portion 2 is secured by packing or the like (not shown).

  The structure of the catalyst holding part 4 holding the catalyst 5 is a structure having a mesh-like gap, so that the hydrogen liquid fuel 7 can easily enter the catalyst holding part 4, and efficiently contact the catalyst 5. To do. Then, as shown in FIG. 2, when the catalyst holding unit 4 enters the hydrogen fuel storage unit 3 and the catalyst 5 and the hydrogen liquid fuel 7 come into contact with each other, an amount of hydrogen corresponding to the contact area is generated, and the generated hydrogen Is stored in the hydrogen storage unit 2 as indicated by arrows.

  As the catalyst 5, a known catalyst such as nickel, cobalt, zirconium, rhodium, platinum, palladium, platinum, gold, silver, or an alloy containing these can be used. Moreover, what carried these on the carbon fine powder may be sufficient, and what carried out the fluorination treatment of these surfaces can also be used.

Further, if the surface area per unit volume of the catalyst 5 is increased, the contact area with the hydrogen liquid fuel 7 is increased, the efficiency of hydrogen generation is improved, and the catalyst holding unit 4 can be downsized. In order to increase the surface area per unit volume of the catalyst, it may be in the form of particles or powder, and various other well-known structures such as a porous structure or a fractal structure can be used.
Here, if the density of the particles or powder or the above-described structure is made uniform in the immersion depth direction, the contact area is proportional to the immersion amount, and the hydrogen generation amount can be easily controlled.

  The movable part 6 is driven by an ultrasonic motor 8 using a small piezo element. The drive of the movable part 6 may be one that converts a rotational motion of a rack and pinion into a linear motion. The ultrasonic motor 8 is electrically connected to the controller 9 and is driven by a drive signal from the controller 9.

  Also connected to the controller 9 are a pressure sensor 10 as a detecting means provided in the hydrogen storage unit 2 and a supply valve 11 provided in the middle of a supply path 12 connecting the hydrogen reformer 1 and the fuel cell 13. ing.

A method for adjusting the amount of hydrogen generation will be described below.
First, the hydrogen reformer 1 and the device on which the fuel cell 13 is mounted can be started by the method described below.
The supply valve 11 has a function as a differential pressure operation valve that automatically opens the valve when the internal pressure of the hydrogen storage unit 2 becomes a predetermined pressure or higher. Is used as a power source to drive the ultrasonic motor 8 and lower the catalyst holding unit 4 downward to generate hydrogen. When the inside of the hydrogen storage unit 2 reaches a predetermined pressure, the generated hydrogen is supplied to the fuel cell 13 and the fuel cell 13 starts power generation. Here, if the power source of the controller 9 and the ultrasonic motor 8 is provided so as to be switchable to the fuel cell 13, the operation after startup can be performed using the fuel cell 13 as a power source. In this way, the capacity of the start-up secondary battery can be reduced, and the device can be downsized.

  After the start-up, when the amount of hydrogen generated decreases due to deterioration of the catalyst 5 and the pressure in the hydrogen storage unit 2 decreases, the controller 9 responds to the pressure in the hydrogen storage unit 2 detected by the pressure sensor 10. The electric signal is processed, and a signal for moving the movable portion 6 downward is output to the ultrasonic motor 8 to lower the catalyst holding portion 4. As a result, when the amount of immersion increases, the amount of generated hydrogen increases again. The controller 9 also outputs a signal to throttle the supply valve 11 to the supply valve 11 to increase the pressure in the hydrogen storage unit 2.

When the pressure rises more than necessary, the controller 9 processes an electrical signal corresponding to the pressure in the hydrogen storage unit 2 detected by the pressure sensor 10 and moves the movable unit 6 upward to the ultrasonic motor 8. The catalyst holding part 4 is pulled up by outputting the signal to be made. When the catalyst holding part 4 is pulled up, the amount of immersion decreases and the amount of hydrogen generation decreases immediately. The controller 9 also outputs a signal for further opening the supply valve 11 to supply a large amount of hydrogen to the fuel cell 13 and reduce the pressure inside the hydrogen storage unit 2.
By the above two feedback processes, the pressure after startup in the hydrogen reforming apparatus 1 is kept constant, and hydrogen is also supplied stably.
In the present embodiment, the fuel cell 13 is shown as a hydrogen supply destination, but the supply destination is not limited to this.

According to this embodiment, there are the following effects.
(1) Since the catalyst holding part 4 moves directly by the physically connected movable part 6 and contacts and reacts with the hydrogen liquid fuel 7, the contact area can be adjusted reliably, and hydrogen is generated. The amount can be precisely controlled. Moreover, since an incidental mechanism for adjusting the supply amount of the reaction object is not necessary, a small hydrogen reforming apparatus 1 that is easy to handle can be obtained.

(2) Since the movable part 6 moves substantially on a straight line, the movable structure can be simplified and reduced in size. Accordingly, the entire apparatus can be reduced in size.

(3) By providing the hydrogen storage unit 2 with the pressure sensor 10, the amount of hydrogen generated can be controlled by the pressure in the hydrogen storage unit 2, and it is not necessary to maintain a high pressure. Can be small. Moreover, the pressure in the hydrogen reforming apparatus 1 can be made constant, and hydrogen can be supplied stably.

(4) Since the hydrogen liquid fuel storage unit 3 is detachably connected, replenishment and replacement of spent fuel can be performed for each container as the hydrogen liquid fuel storage unit 3, and a supply mechanism such as a valve or a pump Is unnecessary, and handling can be simplified.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in the above embodiment, the catalyst 5 is held in the catalyst holding unit 4 and hydrogen is generated by contact with the hydrogen liquid fuel 7. In the present invention, particulate Mg is used instead of the catalyst 5. Alternatively, hydrogen may be generated by reacting with water.
In the present invention, in order to make the catalytic reaction more efficient, the catalyst support 4 may be provided with a heating mechanism.

The best configuration, method and the like for carrying out the present invention have been disclosed in the above description, but the present invention is not limited to this. That is, the invention has been illustrated and described primarily with respect to particular embodiments, but may be configured for the above-described embodiments without departing from the scope and spirit of the invention. Various modifications can be made by those skilled in the art in terms of materials, quantity, and other detailed configurations.
Therefore, the description limited to the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such restrictions is included in this invention.

1 is an overall conceptual diagram of a hydrogen reformer. The whole conceptual diagram at the time of hydrogen generation with a hydrogen reformer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hydrogen reformer, 2 ... Hydrogen storage part, 3 ... Hydrogen liquid fuel storage part, 4 ... Catalyst holding part, 5 ... Catalyst, 6 ... Movable part, 7 ... Hydrogen liquid fuel, 8 ... Ultrasonic motor, 9 ... Controller, 10 ... Pressure sensor as detection means, 11 ... Supply valve, 12 ... Supply path, 13 ... Fuel cell.

Claims (4)

A hydrogen liquid fuel storage unit;
A catalyst holding unit that is provided so as to be immersed in the hydrogen liquid fuel in the hydrogen liquid fuel storage unit and holds the catalyst; and
Detecting means for detecting a hydrogen amount of hydrogen generated by a reaction between the hydrogen liquid fuel and the catalyst;
A hydrogen reforming apparatus, comprising: a controller that adjusts the amount of immersion of the catalyst holding unit according to the detection result of the detection means. The hydrogen reformer according to claim 1,
The hydrogen reforming apparatus, wherein the catalyst holding part moves on a substantially straight line. In the hydrogen reforming apparatus according to claim 1 or 2,
The hydrogen reforming apparatus characterized in that the detection means is a pressure sensor. In the hydrogen reforming apparatus according to any one of claims 1 to 3,
The hydrogen reforming apparatus, wherein the hydrogen liquid fuel storage unit is detachable.

Images