JP2004115348A - Hydrogen generation system, automobile equipped with the same and cartridge for hydrogen generation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen generation system with a simple structure which constantly generates hydrogen with high efficiency without any special improvement of infrastructure or special emission control. <P>SOLUTION: The hydrogen generation system 1 is composed of a water-storage vessel 2, a cartridge 3 wherein a silicon powder 30 is sealed, a circulation means P<SB>1</SB>and C<SB>1</SB>-C<SB>2</SB>for passing water through the cartridge, a heat source 4 for heating water, water-collecting means 5 and 6 for collecting hydrogen generated in the cartridge and a silicon oxide-removing means F<SB>2</SB>for removing silicon oxide generated in the cartridge. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydrogen generator and an automobile equipped with the same.
[0002]
[Prior art]
In recent years, hydrogen has attracted attention as an alternative fuel to oil in view of depletion of existing resources such as oil and emission of carbon dioxide.
Fuel cell systems that generate power using hydrogen as fuel have been developed, and their use in various fields such as automobiles and mobile terminals has been studied.
[0003]
In a conventional fuel cell system, as a hydrogen supply system for supplying hydrogen as a fuel, it is common to inject gaseous fuel into a tank by compression or to inject liquid fuel while keeping it at a low temperature.
In the case of a gas fuel tank for compressing and injecting gaseous hydrogen, a high-pressure tank having a pressure resistance of usually about 350 atm is required, and a high strength fuel tank is required.
On the other hand, in the case of a liquid fuel tank for injecting liquid hydrogen, adiabatic compression is indispensable for fuel injection. In a liquid fuel tank with adiabatic compression, it is difficult to balance the material level of the tank with high strength, so it is common to adjust the internal pressure of the tank by releasing hydrogen from the tank at regular intervals. is there.
[0004]
On the other hand, a reformer for extracting hydrogen gas from hydrocarbons such as gasoline and alcohol in order to mount a fuel cell system in an automobile or the like has been developed. Furthermore, there is a movement to supply hydrogen by mounting a power generation auxiliary device such as a solar cell and a water electrolysis device on a vehicle.
[0005]
Still other methods for producing hydrogen include a method in which an alkali metal such as sodium or magnesium or an alkaline earth metal is reacted with water, and a method in which water vapor is brought into contact with iron to obtain hydrogen (Non-Patent Document 1).
Patent Document 1 discloses a method for producing hydrogen by bringing silicon fine powder having an average particle diameter of 2 μm or less into contact with water.
[0006]
[Non-patent document 1]
Kiyoshi Otsuka, "Environmentally Friendly Cars Running on Iron and Water Are Near" [online] Tokyo Institute of Technology, August 220, 2002, Internet <URL: http: // www. titech. ac. jp / tokyo-tech-iin-the-news / j / archives / 2002/08/1029974400. html>
[Patent Document 1]
JP-A-4-59601 (pages 1-2)
[0007]
[Problems to be solved by the invention]
However, when gaseous hydrogen is stored in the fuel tank, the filling efficiency is low. For example, when the gaseous hydrogen is mounted on a car, there is a problem in the amount of power generation such as a short traveling distance. On the other hand, in the case of a liquid fuel tank for storing hydrogen in a liquid state, it is necessary to cool the tank even after injection because hydrogen is vaporized even at normal pressure, and there is a problem that the loss during fuel injection is large. In addition, the infrastructure of these hydrogen fuel tanks has not been developed.
[0008]
When the reformer is mounted on an automobile or the like, there is a problem that the unit price of starting materials such as gasoline and alcohol is high. Furthermore, when hydrogen is extracted from these starting materials, it is said that a minimum amount of heat of about 600 ° C. is required for gasoline and about 300 ° C. for alcohol (methanol). Remains. Further, since the reforming rate does not become 100%, there remains a problem in terms of discharge of unreacted gasoline and alcohol, gasoline and alcohol in the course of reaction, and the like.
[0009]
When a solar cell and a water electrolysis system are combined, the solar cell cannot generate electricity at all times, and the electrolysis itself requires a large amount of electric energy. Difficult to maintain distance.
[0010]
In addition, the method described in Non-Patent Document 1 has disadvantages in that a trace element must be added to iron in order to continuously obtain hydrogen from iron, and that the working temperature and working pressure are high. In addition, this method requires that water be reacted with iron as water vapor.
[0011]
Furthermore, the method described in Patent Literature 1 has a problem in practical use because the total amount of generated hydrogen is small and the amount of generated hydrogen cannot be controlled.
Therefore, an object of the present invention is to provide a hydrogen production apparatus capable of constantly generating hydrogen with a simple configuration, high efficiency, and without the need for special exhaust measures without maintaining a special infrastructure. That is.
Another object of the present invention is to provide an automobile equipped with such a hydrogen generator.
[0012]
[Means for Solving the Problems]
A hydrogen generating apparatus according to claim 1 of the present invention for solving the above-mentioned problems has a container for storing water, a cartridge filled with silicon powder, a circulating means for passing water through the cartridge, and a heater for heating water. And a water collecting means for collecting hydrogen generated in the cartridge, and a silicon oxide removing means for removing silicon oxide generated in the cartridge.
[0013]
With this configuration, the hydrogen generator of the present invention uses water as a fuel, and therefore does not require a special infrastructure, as compared with the related art requiring a fuel tank. Also, the device is much simpler and requires less energy compared to those using a fuel reformer. Furthermore, since the hydrogen generator of the present invention is driven by, for example, hot water, the reaction efficiency is high. Furthermore, since the hydrogen generator of the present invention uses water as a raw material, it is emissionless. Further, the hydrogen generator of the present invention can always generate hydrogen even at night or the like, as compared with a power generation system in which a solar cell and water electrolysis are combined.
[0014]
An invention according to claim 2 is an automobile equipped with the hydrogen generator and the internal combustion engine according to claim 1, wherein the water stored in the water tank uses heat of exhaust gas or heat of engine cooling water. And heating to 40 to 98 ° C. With this configuration, it is possible to reduce energy loss by utilizing the heat of the internal combustion engine, to improve the fuel efficiency by utilizing the hydrogen-added engine, and to further reduce the hydrogen contained in the exhaust gas. Emission due to addition can be reduced.
[0015]
A third aspect of the present invention is a hydrogen generation cartridge enclosing silicon powder and having water ports at both ends.
With this configuration, it is possible to generate hydrogen with a simple configuration in which the water inlet / outlet of the cartridge is connected to the water circulation means.
In particular, the hydrogen generation cartridge according to the third aspect can be suitably used as a replacement cartridge in the hydrogen generation apparatus according to the first aspect.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
(principle)
The present invention is based on generating hydrogen by an oxidation reaction between silicon (Si) and water (H ₂ O). First, the principle of hydrogen generation of the present invention will be described.
_{Si + 2H 2 O → SiO 2} + 2H 2 (2)
[0017]
The silicon used at this time is granular silicon having an average particle diameter of more than 2 μm, more preferably an average particle diameter of 5 to 100 μm, and still more preferably an average particle diameter of 10 to 40 μm. If the average particle size of silicon is 2 μm or less, voids between silicon particles are small, and water hardly penetrates into the voids. Conversely, if the average particle size of silicon is too large, the specific surface area, that is, the contact area with water, becomes small, so that the reaction tends to be difficult to proceed.
[0018]
In the present invention, particularly preferred silicon is silicon particles sized to have a predetermined particle size distribution by, for example, a shifter, sieving or the like.
On the other hand, as the water to be reacted with silicon in the present invention, various waters such as tap water, industrial water, and seawater can be used, and the water is not limited to pure water. The water used in the present invention needs to be liquid in the reaction system. Further, in the present invention, it is not necessary to adjust the pH of the water used for the reaction.
That is, water at 0 ° C. or higher and 100 ° C. or lower at normal pressure is used in the reaction of the present invention.
The temperature of the water used in the hydrogen production method of the present invention is not particularly limited, but experiments by the present inventors have shown that the higher the temperature, the more the reaction proceeds. That is, the temperature of the water to be reacted with silicon is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, and further preferably 85 ° C. or higher.
[0019]
In addition, according to experiments performed by the present inventors, it has been found that when the water temperature decreases and the amount of generated hydrogen decreases, heating can increase the amount of generated hydrogen again.
Therefore, it is considered that the amount of hydrogen generated by the reaction of the present invention can be controlled by adjusting the water temperature. It is considered that the amount of hydrogen generated by the reaction of the present invention can be similarly controlled by changing the pressure of the reaction system in addition to or instead of changing the water temperature.
Furthermore, when the reaction proceeds after a predetermined time and silicon dioxide precipitates in water, the amount of generated hydrogen decreases.However, when water is replaced with new one, the amount of generated hydrogen may increase. It turns out that it is possible.
[0020]
(Hydrogen generator)
The present invention is an apparatus for generating hydrogen by the reaction between water and silicon having a predetermined shape. Hereinafter, the hydrogen generator of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing one embodiment of the hydrogen generator of the present invention.
As shown in FIG. 1, the hydrogen generator 1 of the present invention includes a circulation pump P _1, the water passage C ₁ -C ₃ in which water is circulated, the water tank 2 for water, silicon reactions composed of silicon powder A cartridge 3 including the unit 30, a heat source 4 (a heat exchanger in the illustrated example) for adjusting the water temperature provided upstream (C ₁ side) of the cartridge 3, and a water passage C ₁ downstream of the cartridge 3. A gas-liquid separation device 5 and a hydrogen permeable membrane 6 for separating hydrogen obtained by the oxidation reaction of silicon provided above, and a silicon oxide obtained by the oxidation reaction of silicon provided in the water passage are removed. It is composed primarily of removing means F ₂ Metropolitan for.
[0021]
The circulating pump P ₁ pumps water stored in the water tank 2 to the cartridge 3 through a water passage C ₁ on the downstream side of the water tank 1, and is different from a conventionally known one such as an automobile part. It is appropriately selected. At this time, as desired, in order to remove impurities of water stain and dust in the water water in the water tank 2 may be provided means for removing F _1, such as water tank filter. Also, how to send the water used for the reaction into the cartridge 3 from the water tank 2 through the circulation pump P ₁ may be a continuous, for example, every 10 minutes may be sent intermittently water or continuous and intermittent May be combined.
[0022]
Furthermore, a flow meter Q for measuring the downstream flow rate to the pipe C ₂ of water in the cartridge 3 is provided, and provided flow rate adjusting means to the pipe C ₁ on the upstream side of the cartridge 3, for example, the gate valve GV (or needle valve) Thus, a configuration for controlling the flow rate of water may be adopted.
Although not shown, a configuration may be adopted in which a measuring unit for measuring the amount of generated hydrogen is provided downstream of the hydrogen permeable membrane 6, and the supply amount of water is controlled according to the amount of hydrogen measured by the measuring unit. it can.
[0023]
The water tank 2 is a plastic or stainless steel tank for storing water for reacting with silicon contained in the cartridge 3 of the hydrogen generator 1 of the present invention. The water filled with silicon from the water tank 2 via the circulation pump P ₁ is heated to a predetermined temperature by a heat source 4 arranged at any position from the water tank to a water inlet (not shown) of the cartridge 3. Warmed up.
Incidentally, the water lost by the reaction in order to supply to the water tank 2, the position of the water tank near the pipe C ₂ on the downstream side of the cartridge 3 (i.e., the downstream side of the filter F ₂₎ a three-way valve V provided in the pump The water tank 2 can be configured to supplement water from P2.
[0024]
The reason why the water is heated in the hydrogen generator 1 of the present invention is that, as described above, when the water temperature is increased to 40 ° C. or higher, the amount of generated hydrogen increases. Further, in FIG. 1, a configuration of providing a heat source 4 to the pipe C ₁ on the upstream side of the cartridge 3, the arrangement of the heat source 4 is not limited here. For example, a configuration in which the heat source 4 is directly connected to the cartridge 3 is also possible, and a configuration in which a heating unit is provided as the heat source 4 in the water tank 2 is also possible. Furthermore, when the hydrogen generator 1 of the present invention is mounted on a vehicle, water heated using exhaust gas or cooling water can be used. In this case, an engine that exchanges heat with exhaust gas or engine cooling water should also be interpreted as meaning the heat source 4 of the present invention.
[0025]
In the hydrogen generator 1 of the present invention, the number of the heat sources 4 is not particularly limited, and two or more heat sources can be provided.
The arrangement and the number of the heat sources 4 can be appropriately selected according to the intended use. That is, as shown in FIG. 1, providing a heat source pipe C ₁ on the upstream side of the cartridge 3, the water used for the reaction, since heating at a position close to the silicon reactor 30 is a reaction site, heat loss is small On the other hand, when a heat source is provided in the water tank 2 for storing a large amount of water (or when exhaust gas or engine cooling water is used), it is advantageous in that a stable water temperature can be obtained. .
[0026]
In this way, when water at a predetermined temperature flows from the water tank 2 to the cartridge 3 at a predetermined flow rate through the cartridge 3, the silicon particles filled in the silicon reaction section 30 of the cartridge 3 react with the water to form hydrogen. appear. The generated hydrogen is separated into water and hydrogen by a gas-liquid separation device, for example, a cooling pipe, and further separated by a hydrogen separation membrane 6, generally a hydrogen separation membrane 6 made of palladium, ruthenium or an alloy thereof. To a hydrogen supply system or a hydrogen storage system. In this embodiment, the gas-liquid separation device 5 and the hydrogen separation membrane 6 correspond to hydrogen separation means.
[0027]
At this time, the silicon reaction section 30 incorporated in the cartridge 3 is a packed layer filled with silicon particles having the above-mentioned predetermined average particle size. The method of filling the silicon particles at this time may be determined by a method known in the art such as a fixed bed type, a fluidized bed type or a moving bed type, from the flow rate of water (that is, flow pressure) and the reaction efficiency. It is appropriately selected in consideration of the above.
Further, although the silicon reaction section 30 in the hydrogen generator of the present invention shown in FIG. 1 is a single layer, it goes without saying that a plurality of layers may be provided.
[0028]
On the other hand, the water after the reaction with the silicon reaction unit 30 is returned to the water tank 2 through a pipe C ₂ on the downstream side. At this time, the water after the reaction with the silicon reaction unit 30, the silicon oxide is contained which is generated by the reaction, any portion of the up flowing through a pipe C ₁ on the downstream side to the water tank 2 It is necessary to provide a removing means for removing silicon oxide. As such removal means, including but means separation such as, for example, by filtration and centrifugation by the filter, and a removal means of simple filter F ₁ is configured in the example shown in FIG.
[0029]
In this manner, the hydrogen generator 1 of the present invention is a device that efficiently generates hydrogen by the silicon reaction unit 30 built in the cartridge 3 while circulating water.
When the hydrogen generator 1 of the present invention is not operating, that is, when the hydrogen generator 1 is in a stopped state, it is desirable that water does not exist in the cartridge 3. As a method of extracting the water in the cartridge 3, for example, by providing a C _D piping for the upstream side of the water in the low part removal of the silicon reaction portion 30 of the cartridge 3, the water tank by opening and closing the drain valve DV for drainage The structure which drops unnecessary water from 2 can be used. When the lower part of the upstream side of the silicon reaction portion 30 of the cartridge 3 provided C _D piping for such withdrawn relatively clean water so that the supply to the water tank 2.
[0030]
The hydrogen generator of the present invention configured as described above uses water as a fuel, so that no special infrastructure is required. Further, as compared with the apparatus using a fuel reformer, the hydrogen generator of the present invention has a very simple configuration and requires less energy consumption. Furthermore, since the hydrogen generator of the present invention is driven by hot water, the reaction efficiency is good. Furthermore, since the hydrogen generator of the present invention uses water as a raw material, it is emissionless. Further, the hydrogen generator of the present invention can always generate hydrogen even at night or the like, as compared with a power generation system in which a solar cell and water electrolysis are combined. Therefore, when such a hydrogen generator of the present invention is mounted on an automobile together with an internal combustion engine, it can be effectively used as an energy source of the automobile.
[0031]
In this case, it is advantageous in terms of energy if the exhaust gas of the automobile or the cooling water of the engine is used as the heat source of the hydrogen generator of the present invention.
The hydrogen generator of the present invention can also be used as auxiliary energy for, for example, a fuel cell vehicle, a hybrid fuel vehicle, or an electric vehicle. In that case, for example, hydrogen generated by the hydrogen generator of the present invention can be guided to, for example, a fuel tank described in the related art.
[0032]
Further, as the simplest configuration of the present invention, the hydrogen generation cartridge 3 shown in FIG. 1 can be used alone. That is, the cartridge 3 for hydrogen generation described with reference to FIG. 1 can be suitably used as the replacement cartridge of the present invention, and the silicon reaction section 30 can be supplied from the inlet of the cartridge 3 without circulating water. Hydrogen can be generated by flowing water toward the outlet of the cartridge through the.
【The invention's effect】
As described above, the present invention has the following excellent effects.
The invention according to claim 1 requires no special infrastructure because the hydrogen generator of the present invention uses water as a fuel, as compared with the conventional technology requiring a fuel tank. Also, the device is much simpler and requires less energy compared to those using a fuel reformer. Furthermore, since the hydrogen generator of the present invention is driven by, for example, hot water, the reaction efficiency is high. Furthermore, since the hydrogen generator of the present invention uses water as a raw material, it is emissionless. Further, the hydrogen generator of the present invention can always generate hydrogen even at night or the like, as compared with a power generation system in which a solar cell and water electrolysis are combined.
[0033]
The invention according to claim 2 makes it possible to reduce energy loss by utilizing the heat of the internal combustion engine, to improve the fuel economy by using the hydrogen-added engine, and to further reduce the hydrogen contained in the exhaust gas. Emission due to addition can be reduced.
According to the third aspect of the present invention, it is possible to generate hydrogen with a simple configuration in which the water inlet / outlet of the cartridge is connected to the water circulation means.
In particular, the hydrogen generation cartridge according to the third aspect can be suitably used as a replacement cartridge in the hydrogen generation apparatus according to the first aspect.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing one embodiment of a hydrogen generator of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 hydrogen generator 2 water tank 3 cartridge 30 silicon reactor 4 heat source 5 gas-liquid separator 6 hydrogen permeable membrane

Claims (3)

A container for storing water,
A cartridge filled with silicon powder,
Circulation means for passing water through the cartridge;
A heat source for heating water,
Water collecting means for collecting hydrogen generated in the cartridge,
Silicon oxide removing means for removing silicon oxide generated in the cartridge,
A hydrogen generator comprising: An automobile equipped with the hydrogen generator according to claim 1 and an internal combustion engine,
An automobile equipped with a hydrogen generator, wherein the water stored in the water tank is heated to 40 to 98 [deg.] C. by using heat of exhaust gas or heat of engine cooling water. A hydrogen generation cartridge containing silicon powder and having water ports at both ends.

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