WO2004094306A1

WO2004094306A1 - Hydrogen generator and hydrogen generating method

Info

Publication number: WO2004094306A1
Application number: PCT/JP2004/005748
Authority: WO
Inventors: Shinfuku Nomura; Hiromichi Toyota; Kenya Matsumoto
Original assignee: Techno Network Shikoku Co. Ltd.; Shikoku Electric Power Co. Inc.
Priority date: 2003-04-21
Filing date: 2004-04-21
Publication date: 2004-11-04
Also published as: JP4710048B2; JPWO2004094306A1

Abstract

A hydrogen generator comprising a container for holding a liquid containing a hydrogen compound, an air bubble-forming means for forming air bubbles in the liquid, an electromagnetic wave generator for irradiating the liquid with an electromagnetic wave, and a hydrogen collecting means is disclosed wherein the hydrogen compound is decomposed by generating a plasma in the liquid and the thus-generated hydrogen is collected. This hydrogen generator enables to generate hydrogen at a high reaction rate and a high energy efficiency by generating a high-energy plasma in the liquid.

Description

Hydrogen generator and hydrogen generating method

Technical field

The present invention relates to an apparatus and a method for generating hydrogen by decomposing a hydrogen compound.

Akira Background technology

Rice field

Hydrogen is a highly demanded substance used in the chemical industry as a reducing agent. It is also used for fuel cells as clean energy. Water electrolysis is a conventional hydrogen generation method, but it is expensive and not practical. The most practical and practical hydrogen generation method is a steam reforming method. In this method, water vapor is mixed with a fossil fuel gas such as methane and chemically reacted at a high temperature to obtain hydrogen and carbon monoxide. This steam reforming method has the advantage of low cost, but generates a large amount of carbon monoxide and carbon dioxide. In addition, Japanese Patent No. 2711368 and Japanese Patent No. 2871182 describe production of hydrogen and carbon black by decomposing methane or natural gas by plasma. I have.

He stated that water electrolysis was expensive and impractical. On the other hand, the steam reforming method costs less, but generates large amounts of carbon monoxide and carbon dioxide. These gases are responsible for global warming. The methods according to the inventions of Patent Nos. 2,711,368 and 2,687,182 provide a yield of almost 100% of carbon and hydrogen of hydrocarbons, and

However, it is described that none of these products in the reaction step was found to be substantially contaminated by the step (for example, see Patent No. 2711 368, page 3, right column, page 3). 10 rows). Patent No. 2 7 1 1 3 6 8 The inventions disclosed in Japanese Unexamined Patent Publication No. 28671182 are based on gas-phase plasma that generates plasma between electrodes in a gas such as methane gas, and it is difficult to increase the energy density of plasma. The reaction speed is limited. In addition, plasma is generated at a high temperature and is inconvenient to handle, and it is difficult to maintain safety because methane gas reacts at a high temperature. SUMMARY OF THE INVENTION An object of the present invention is to provide an effective hydrogen generating apparatus and a hydrogen generating method using plasma in liquid which is locally high in energy, macroscopically low in temperature and low in pressure, safe and easy to handle. I do. Disclosure of the invention

In order to solve the above-mentioned problems, a hydrogen generator of the present invention includes: a container for containing a liquid containing a hydrogen compound; a bubble generating means for generating bubbles in the liquid; and an electromagnetic wave generator for irradiating the liquid with electromagnetic waves. And a hydrogen recovery means, which generates plasma in the liquid to decompose the hydrogen compound and recover the generated hydrogen. Further, a carbon recovery means may be provided. Alternatively, it may have a supply means for continuously supplying liquid to the container, and a discharge means for continuously discharging liquid from the container. The bubble generating means may be an ultrasonic generator that irradiates ultrasonic waves into the liquid to generate bubbles.

Furthermore, in order to solve the above-mentioned problems, the hydrogen generation method involves placing a liquid containing a compound containing hydrogen and carbon in a container, generating bubbles in the liquid in the container, and irradiating electromagnetic waves to generate plasma in the liquid. The method is characterized in that the compound is decomposed to generate hydrogen, a carbon compound is synthesized, and the generated hydrogen and the carbon compound are recovered. A catalyst that promotes the decomposition reaction may be mixed in the liquid. In addition, carbon nanotubes are synthesized in a liquid, and the generated hydrogen is adsorbed on the carbon nanotubes. W 200

3 It may be collected. In the present invention, the term “synthesis of a carbon compound” includes, in addition to synthesizing a substance composed of carbon and another element, synthesizing a substance composed only of carbon, such as diamond-fullerene and carbon nanotube. The invention's effect

The hydrogen generating apparatus and the hydrogen generating method of the present invention have an effect that hydrogen can be efficiently generated by generating plasma in a liquid. Although this plasma is high temperature and high pressure, it is macroscopically low temperature and low pressure because it is generated in the liquid, and it is easy to handle and safe. In addition, it does not generate a large amount of carbon monoxide or carbon dioxide, which causes global warming, and meets the demand for clean energy. If a hydrocarbon is used as a raw material liquid to generate hydrogen and simultaneously synthesize a carbon compound such as -U carbon such as fullerene or carbon nanotube, the cost is further improved. Wastes such as cooking oil and engine oil that have been used as hydrocarbons in the raw material liquid can also be used, and the waste can be converted into valuable resources and reused. Advantageously. The use of the present invention also has the advantage of reducing the amount of secondary waste. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an explanatory view showing a hydrogen generator of the present invention. Fig. 2 is a graph showing the emission spectrum of the plasma. FIG. 3 is an explanatory view showing an embodiment of the hydrogen generator of the present invention. FIG. 4 is an explanatory diagram showing an embodiment of another hydrogen generator according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

BEST MODE FOR CARRYING OUT THE INVENTION In order to show the present invention in more detail, the best mode for carrying out the present invention will be described below. FIG. 1 is an explanatory diagram showing a hydrogen generator. The hydrogen generator 1 has a container 2 for holding a liquid 3. This liquid 3 contains a compound containing hydrogen. The apparatus has a bubble generating means for generating bubbles in the liquid. In the example of FIG. 1, the ultrasonic generator 4 is a means for generating bubbles. Further, an electromagnetic wave generator 5 for irradiating the liquid 3 with electromagnetic waves is provided. The container can be appropriately selected according to the type and amount of the target substance to be treated, and may be as large as a flask for processing a small amount, or a large processing tank for processing a large amount. Alternatively, the pipe may have a passage time for the time required for the liquid to be continuously processed at a high speed.

By this ultrasonic irradiation, many small bubbles 6 are generated in the liquid. An electromagnetic wave generator 5 is provided so as to irradiate the place where the bubbles 6 are generated with electromagnetic waves. As means for generating bubbles, in addition to the ultrasonic generator, means for generating bubbles by depressurizing the inside of the container with a pressure reducing means such as a vacuum pump, or means for generating bubbles by providing heating means in a liquid. Can also be used.

The ultrasonic generator 4 irradiates the liquid 3 in the container 2 with ultrasonic waves, and the ultrasonic waves generate a large number of bubbles 6 in the liquid in a cloud shape. The force in which the substance originating from the liquid 3 in the container 2 is contained in the gaseous phase in the bubble 6. At the time of contraction, the compression becomes almost adiabatic compression, and becomes extremely high pressure and high temperature in the bubble 6, so that plasma is easily generated. The hydrogen generator according to the present invention is provided with an electromagnetic wave generator 5 so as to irradiate the position where bubbles 6 in the liquid are generated with electromagnetic waves. As the electromagnetic waves, the plasma to be generated The frequency and output can be selected according to the type and intensity of the microwave, but microwaves of about 2 GHz or more are mainly used. By superimposing electromagnetic waves on high temperature and high pressure by ultrasonic waves, high energy plasma is generated in bubbles.

As described above, a high-density high-energy plasma can be generated in a liquid. The plasma is already encapsulated in the gas bubbles, and confinement of the generated plasma, which is a major problem in plasma technology, is not a problem in the present invention. Although high-temperature and high-pressure plasma is locally generated, it is confined in a liquid with a large heat capacity and is macroscopically low in temperature. Therefore, there is no need to heat anything outside the device or in contact with the device. The plasma generated in this way is high in temperature and pressure, has a high energy density, and is easy to handle. Acoustic cavitation includes single bubbles (single bubbles) and multiple bubbles (multi bubbles), and the present invention can be applied to both. Although the overall energy is small in a single bubble, a high energy state of 50,000 K to 100,000 mm can be obtained only by ultrasonic irradiation in the bubble. On the other hand, the temperature of a multibubble is slightly lower and is only about 500 000 mm by ultrasonic irradiation alone. However, the total energy amount is large, which is advantageous for industrial use. The hydrogen generator according to the present invention is simple and small, and can be made to be large enough to be placed on a desk. It can also be.

An example of hydrogen generation by the hydrogen generator 1 shown in FIG. 1 will be described. The liquids were used, which is a type of hydrocarbon dodecane _{_{(C 1 2 H 2 6)}} . The electromagnetic wave was a microwave of 2.45 GHz, and 50 W was irradiated into the liquid (input 200 W, reflection 15 ◦ W). The ultrasonic wave was irradiated at 50 KHz at an output of 50 W. An exhaust pipe 7 is provided at the top of the container 2, and the gas in the container 2 is sucked by a rotary pump 8. The gas that has passed through the rotary pump 8 is collected from the end 9 of the exhaust pipe. Further, the hydrogen generator 1 is provided with an inert gas supply means 10, and here, an argon gas supply means 10 a and a nitrogen gas supply means 10 b are provided. The inert gas is supplied from the inert gas supply means 10 into the container 2 by the inert gas supply pipe 11. The inert gas supply pipe 11 is provided with a flow meter 12 and control valves 13 a and b. Adjusting the control valves 13 a and b while checking the flow rate with the flow meter 12 Supply an appropriate amount of inert gas into the container 2.

First, the rotary pump 8 was operated to reduce the pressure in the vessel 2 to 500 Pa, and the liquid was irradiated with ultrasonic waves and electromagnetic waves to generate plasma in the liquid. By reducing the pressure, plasma is more likely to be generated than under atmospheric pressure.

FIG. 2 is a graph showing the emission spectrum of this plasma. From the peak C ₂ indicates that they are generated in a large amount is observed, Togawakaru this the hula one lens, and New carbon such as carbon nanotube has occurred. Further, there is also a peak indicating that hydrogen is generated, and it can be confirmed that hydrogen is generated by the hydrogen generator and the hydrogen generating method of this example.

The pressure in the vessel 2 was increased to 5 KPa by decomposing dodecane by the liquid plasma to generate hydrogen. The gas collected in the container 2 was collected by a syringe from the gas collection port 14 provided in the container 2 in an amount of 100 ml (at atmospheric pressure, 5 ml). The collected gas was analyzed by gas chromatography 24 hours later, and as a result, a high concentration of hydrogen of 40% or more was detected. Considering that a considerable amount of hydrogen had been washed away before the analysis, high-purity hydrogen was generated. Hydrogen was generated by mixing a catalyst to promote the reaction to generate hydrogen in the liquid, but hydrogen was also generated without a catalyst. W

7 I was able to live.

As described above, the hydrogen generator of the present invention decomposes a hydrogen compound by high-energy plasma generated in a liquid. Since the raw material of hydrogen is liquid, the density of the substance is much higher than that of gas such as methane, and the reaction efficiency is high. In addition, since plasma is locally generated in liquid even if it has high energy, it is macroscopically low temperature and low pressure, and is extremely easy to handle and safe. By using a liquid containing a compound containing hydrogen and carbon, hydrogen can be generated and a carbon compound such as new carbon can be obtained at the same time, which is more cost-effective than generating only hydrogen. The electromagnetic wave generator and bubble generator for generating plasma can be controlled electrically and freely by a controller, and the frequency of electromagnetic waves and the output of electromagnetic waves, ultrasonic waves, irradiation time, etc. can be selected, so general-purpose It is highly versatile and can handle various raw material liquids and intended uses. It can be widely used when selecting the type of new carbon generated together with hydrogen.

Another example of generating hydrogen using the hydrogen generator shown in FIG. 1 will be described. In addition to dodecane as a raw material liquid, benzene (C ₆ H ₁₂ ), edible oils and engine oils sold (each shown as “crude oil” in Table 1), and edible oils and engine oils as general liquids Waste oil collected after use for typical purposes was used. 100 ml of each liquid was placed in the container 2. The electromagnetic wave was a microwave of 2.45 GHz, and 30 W was irradiated into the liquid (input 300 W, reflection 270 W). The test was performed under both conditions of irradiation with and without irradiation of ultrasonic waves. The ultrasonic wave used was irradiated at 58 KHz with a power of 5 W. The pressure in the vessel 2 was reduced by operating the rotary pump 8.

Table 1 shows the results of hydrogen generation by the hydrogen generator 1. The hydrogen concentration in the gas obtained from each liquid is shown. In this example, In the raw material liquid, high-purity hydrogen of 60% or more was obtained, and depending on the conditions, a purity of about 80% was obtained. Although high-purity hydrogen is obtained by using edible oil and waste oil from engine oil, there is an advantage that the treatment of these waste oils is performed simultaneously with the generation of hydrogen. Edible oil can be produced agriculturally without using petroleum as a raw material. The fact that it can be used as a raw material for hydrogen also has the significance of utilizing biomass.

Further, Table 2 shows data comparing the energy efficiency of the hydrogen generation method according to this example with the conventional hydrogen generation method. The numbers in Table 2 show the ratio of the energy consumption of the example hydrogen generation method of the present invention to the energy consumption of each conventional technology. For example, the data for Dodecane shows that it consumes 1.10 times more energy than the fossil fuel combustion system, which is considered to be the most energy efficient among the conventional technologies. And are almost equivalent. Other than that, the energy efficiency of the hydrogen generation method of the present invention is equal to or higher than that of many of the conventional technologies. You. Considering that a large amount of carbon dioxide gas such as carbon dioxide is generated by using a fossil fuel combustion system, it is clear that the hydrogen generation method of the present invention that does not generate carbon dioxide gas is excellent. Table 2

Next, the present invention will be described in more detail with reference to examples. FIG. 3 is an explanatory view showing an embodiment of the hydrogen generator. In this embodiment, a premixing chamber 15 is provided upstream of the container for holding the liquid 3. The premixing chamber 15 has a raw material liquid supply port 16 and a catalyst supply port 17, so that the raw material liquid and the catalyst can be supplied to the premixing chamber 15 from the outside. As a raw material, a liquid containing a hydrogen compound, particularly a liquid containing carbon and hydrogen such as hydrocarbons is used. The catalyst is used to accelerate the reaction of decomposing the raw materials to generate hydrogen. For example, palladium is used. The raw material liquid and the catalyst supplied to the premixing chamber 15 are stirred by the stirring means 18 and sufficiently mixed. Further, even in the container 2, the raw material liquid and the catalyst are mixed more satisfactorily by irradiation with ultrasonic waves.

The premixing chamber 15 and the vessel 2 are connected by a pipe 19. The pipe 19 is provided with a control valve 20 so as to regulate the flow of the liquid in the pipe 19. By controlling the control valve 20 so that the liquid at a constant flow rate is continuously supplied, the hydrogen generation processing can be continuously performed. In addition, after supplying a certain amount of liquid to the container 2, the control valve 20 is closed to interrupt the supply, the hydrogen generation process is performed, and after the processed liquid is discharged from the container 2, the process is repeated. 0 The control valve 20 is opened to supply the liquid, and the sequential processing can be performed by repeating the procedure.

An exhaust pipe 7 is provided at the upper part of the container 2 and discharges gas generated inside the container 2 to the outside of the container 2. On the other hand, a liquid discharge pipe 21 is provided at a lower portion of the container 2 so as to discharge the liquid in the container 2 to the outside.

The exhaust pipe 7 is connected to a separation membrane 22 that selectively allows only hydrogen from the gas to pass therethrough. Hydrogen that has passed through the separation curtain is recovered as hydrogen gas. Gas that does not pass through the separation membrane 22 is exhausted as it is.

A settling tank 23 is connected to the liquid discharge pipe 21. New carbon and catalyst such as carbon nanotubes contained in the liquid discharged from the container 2 are collected as a precipitate. Other liquids are discarded. The recovered catalyst is put into the premixing chamber 15 again and reused. That is, in the present embodiment, the sedimentation tank 23 functions as carbon recovery means.

Another embodiment of the present invention will be described. FIG. 4 is an explanatory view showing another embodiment of the hydrogen generator. Also in this embodiment, a premixing chamber 15 is provided so that the raw material liquid and the catalyst are sufficiently mixed in advance and then supplied to the vessel 2. In this embodiment, no exhaust pipe is provided, and only the liquid discharge pipe 21 is provided.

There are two types of hydrogen generation methods using the hydrogen generator of this embodiment. The first method uses a substance that absorbs hydrogen as a catalyst. Hydrogen compounds are decomposed by the plasma generated in the liquid in the container 2 to generate hydrogen, and this hydrogen is adsorbed on the catalyst. The hydrogen-adsorbed catalyst is discharged out of the container 2 through the liquid discharge pipe 21 in a state of being contained in the liquid, and is conveyed to the heating tank 24.

The second method uses a liquid containing hydrocarbons as a raw material liquid. First, it generates hydrocarbons by the plasma generated in the liquid in the container 2 to generate hydrogen and synthesizes new carbon such as carbon nanotubes. The generated hydrogen is adsorbed on the new carbon. The new carbon that has absorbed the hydrogen is transported to the heating tank 24 through the liquid discharge pipe 21.

The heating tank 24 is provided with a heater 25 for heating the inside of the heating tank. The liquid carried to the heating tank 24 by the heater 25 is heated, and the hydrogen adsorbed on the catalyst or the new carbon is separated and collected as a gas. New carbon remaining in the heating tank 24 is also recovered. That is, in this embodiment, the heating tank 24 functions as carbon recovery means. Industrial applicability

According to the present invention, since hydrogen is generated by generating plasma in a liquid, it can be used as a hydrogen generation technology having a high reaction rate and high energy efficiency. Since a carbon compound can be produced simultaneously with hydrogen production, it can be used as a device that combines hydrogen production and carbon compound production. Since hydrogen can be obtained without generating carbon dioxide, it can be used as a pollution-free energy technology.

Claims

1 2 Scope of request

1. A container for containing a liquid containing a hydrogen compound, bubble generating means for generating bubbles in the liquid, an electromagnetic wave generator for irradiating the liquid with electromagnetic waves, and hydrogen recovery means, and a plasma is generated in the liquid. A hydrogen generator that decomposes hydrogen compounds to recover the generated hydrogen.

2. The hydrogen generator according to claim 1, further comprising a carbon recovery means.

3. The hydrogen generator according to claim 1 or 2, further comprising a supply unit that continuously supplies the liquid to the container, and a discharge unit that continuously discharges the liquid from the container.

4. The hydrogen generator according to any one of claims 1 to 3, wherein the bubble generator is an ultrasonic generator that irradiates ultrasonic waves into the liquid to generate bubbles.

5. A liquid containing a compound containing hydrogen and carbon is placed in a container, bubbles are generated in the liquid in the container, plasma is generated in the liquid by irradiating electromagnetic waves, and the compound is decomposed to generate hydrogen. A method for generating hydrogen, comprising synthesizing a carbon compound and recovering generated hydrogen and the carbon compound.

6. The method for generating hydrogen according to claim 5, wherein the catalyst is mixed into the liquid.

7. The hydrogen generation method according to claim 5, wherein the carbon nanotubes are synthesized in a liquid, and the generated hydrogen is adsorbed and collected on the carbon nanotubes.