WO2013031502A1

WO2013031502A1 - Regenerable energy storage system

Info

Publication number: WO2013031502A1
Application number: PCT/JP2012/070187
Authority: WO
Inventors: 寛人内藤
Original assignee: 株式会社日立製作所
Priority date: 2011-08-31
Filing date: 2012-08-08
Publication date: 2013-03-07
Also published as: JP2013049600A; JP5618952B2

Abstract

Provided is a regenerable energy storage system that can store and supply regenerable energy with high efficiency while taking into consideration variations in the amount of regenerable energy. A regenerable energy storage system (100) stores regenerable energy. The regenerable energy storage system (100) is provided with: a power generating means (1) that converts regenerable energy into electrical energy; a hydrogen production means (2) constituted such that a plurality of hydrogen generating devices (2) that produce hydrogen gas using this electrical energy are connected by pipes; a buffer tank (3) that increases the purity of the hydrogen gas produced by the hydrogen production means (2); a hydrogenation means (4) that adds the hydrogen gas flowing from the buffer tank (3) to an unsaturated hydrocarbon; a switching means (7) that switches the connection constitution of the hydrogen production devices (2); and a controller (8) that controls the switching means (7). Reverse flow preventing mechanisms (9) that prevent the hydrogen gas that is produced from flowing in reverse in the hydrogen production means (2) are provided in the pipes connecting plurality of hydrogen production devices (2) and the buffer tank (3).

Description

Renewable energy storage system

The present invention relates to a storage system for fluctuating energy such as renewable energy.

Mass consumption of fossil fuels continues, for example, global warming due to carbon dioxide, air pollution in urban areas, etc. are becoming serious. Under such circumstances, hydrogen is attracting attention as an energy source for the next generation to replace fossil fuels. Hydrogen can be produced by electrolysis using renewable energy typified by solar cells, wind power, and the like, and further, only water is generated by combustion. Therefore, hydrogen is a clean energy source that emits less environmental pollutants during production and use.

As a method for producing hydrogen, steam reforming of fossil fuel is widely used industrially. In addition to this, many production methods are known for hydrogen, such as by-product hydrogen associated with the production of iron or soda and hydrogen generated by reactions using thermal decomposition, photocatalysts, microorganisms, and water electrolysis. It has been. Especially, as electric power required for electrolysis of water, it is possible to use electric power from various supply sources. Therefore, the method for producing hydrogen by electrolysis of water is regarded as important as a method for producing an energy source independent of a specific region.

However, in order to use hydrogen as an energy source (ie, fuel), hydrogen transportation, storage, supply system, etc. can be a major issue. Specifically, since hydrogen is a gas at normal temperature and pressure, there is a problem that it is difficult to store and transport compared to liquid and solid. Furthermore, hydrogen is a combustible substance, and when air and hydrogen are mixed at a predetermined mixing ratio, hydrogen may react explosively.

As a technique for solving these problems, after desulfurizing a hydrocarbon fuel with a desulfurization apparatus, steam is added and supplied to a steam reformer, where hydrogen is generated, this hydrogen is supplied to a fuel cell, and oxygen and There has been proposed a fuel cell power generation system that reacts to extract electric energy.

In recent years, organic hydride systems using hydrocarbons such as cyclohexane and decalin have attracted attention as a hydrogen storage method that is excellent in safety, transportability and storage capacity. Since these hydrocarbons are liquid at normal temperature and pressure, they can be stored and transported more easily than in the case of gases. For example, benzene and cyclohexane are cyclic hydrocarbons having the same carbon number, while benzene is an unsaturated hydrocarbon having a double bond, whereas cyclohexane is a saturated hydrocarbon having no double bond. That is, by adding hydrogen to benzene that is an unsaturated hydrocarbon, cyclohexane that is a saturated hydrocarbon is obtained. Moreover, benzene is obtained by desorbing hydrogen from cyclohexane. Thus, for example, Patent Document 1 discloses a system that can store and supply hydrogen using a hydrogenation reaction and a hydrogen elimination reaction using benzene and cyclohexane.

However, in order to construct an organic hydride system using renewable energy, it is sometimes necessary to consider the amount of electric power (ie, the amount of power generation) generated by the renewable energy. That is, the amount of power generated by renewable energy usually varies depending on weather conditions. For example, in the case of wind power generation using wind power as renewable energy, the amount of power generation varies depending on the strength of the wind, and in the case of solar power generation using sunlight, the intensity of sunlight and the duration of sunlight.

In order to cope with such a change in the amount of electric power, for example, Patent Document 2 discloses that the maximum output of the solar cell can be obtained by changing the number of electrical series connections of the water electrolysis device according to the generated power of solar power generation. The operation method of the water electrolysis system which utilizes the water efficiently is described.

Further, for example, Patent Document 3 includes a plurality of cell stacks composed of a plurality of water electrolysis cells, and the water electrolysis apparatus configured by connecting the cell stacks electrically in series or in parallel to each other, and the water electrolysis apparatus. A power supply means for supplying power, a voltage control unit for variably controlling the voltage of power supplied to the water electrolysis device, and the number of stacks for selecting the number of cell stacks used according to the power supplied to the water electrolysis device By providing a control unit, an energy-efficient hydrogen production facility using a generator as a power source is described.

Further, for example, Patent Document 4 discloses a water electrolysis apparatus having a plurality of water electrolysis stacks in which a predetermined number of water electrolysis cells are stacked, and a power supply apparatus having at least a voltage fluctuation power supply and supplying power to the water electrolysis apparatus. In the water electrolysis system provided, there is described a water electrolysis system that has a power adjustment unit for each water electrolysis stack so as to individually adjust supply power and drive variable power with the best electrolysis efficiency, and an operation method thereof.

International Publication No. 2006/120841 JP 2001-335982 A JP 2005-126792 A JP 2007-31813 A

For example, when the electric power obtained by wind power generation, solar power generation, etc. is directly stored (i.e., charged) in a power storage device, if the electric power obtained over a long period of time is stored, the capacity of storing a large amount of electric power A power storage device must be used. For this reason, there is a concern that the size of the power storage device may become extremely large or the manufacturing cost of the power storage device may increase. In addition, when it is considered to transport the electric power stored in the power storage device, an extremely large power storage device must be transported, and the transportation becomes complicated.

In addition, according to the conventional technology, a dedicated device is required to control charging / discharging of the power storage device, which increases the equipment cost. Furthermore, as described above, for example, in the case of photovoltaic power generation, the amount of renewable energy changes depending on the intensity of sunlight and the duration of sunlight, so that in some cases, the loss of renewable energy occurs and the renewable energy cannot be used effectively. is there.

On the other hand, in the water electrolysis system and the operation method thereof described in Patent Documents 2 to 4, there are proposed operation methods for adjusting the electrical connection configuration and supply power of the water electrolysis system according to the fluctuating power of renewable energy. The production hydrogen gas collection method is not considered and cannot be combined with the organic hydride system as it is.

Also, it is not possible to connect all the gas pipes of a plurality of water electrolysis apparatuses to the buffer tank as the same pipe. The water electrolysis device is either in operation or not in operation. When all gas pipes are connected to form the same piping, hydrogen gas produced in the operation part flows into the water electrolysis device in the operation part, Gas leakage and, in the worst case, lead to failure of the hydrogen production apparatus that has flowed in.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and its purpose is to provide a renewable energy storage capable of storing and supplying renewable energy with high energy efficiency while taking into account fluctuations in the amount of renewable energy. To provide a system.

As a result of intensive studies to solve the above-mentioned problems, the present inventors at least in a hydrogen production system equipped with a switching control system, other hydrogen gas pipes connected to each hydrogen production means, other buffer tanks and the like The present invention has been completed by finding that the above problem can be solved by providing a backflow prevention mechanism up to the junction point with the apparatus or another gas pipe.

According to the present invention, it is possible to provide a renewable energy storage system that can store and supply renewable energy with high efficiency while taking into account fluctuations in the amount of renewable energy.

It is a schematic diagram showing the structure of the renewable energy storage system by 1st Embodiment of this invention. It is a schematic diagram showing the structure of the renewable energy storage system by 2nd Embodiment of this invention. It is a schematic diagram showing the structure of the renewable energy storage system by 3rd Embodiment of this invention. It is a schematic diagram showing the structure of the renewable energy storage system by 4th Embodiment of this invention. It is a schematic diagram showing the structure of the renewable energy storage system by 5th Embodiment of this invention. It is a schematic diagram showing the structure of the renewable energy storage system by 6th Embodiment of this invention.

Hereinafter, the renewable energy storage system according to the present embodiment will be described using six specific examples with reference to the drawings as appropriate.
[1. First Embodiment]
FIG. 1 is a diagram schematically illustrating a configuration of a renewable energy storage system according to a first embodiment of the present invention. In FIG. 1, a thick solid line represents an electrical wiring, a thin solid line represents a signal line (for example, a control signal, a measurement signal, etc.), and a broken line represents a fuel energy (for example, hydrogen, methylbenzene, etc.) supply line. It is a wiring that connects means, and represents the exchange of signals and fuel energy. Connections between signal lines are indicated by solid circles.

As shown in FIG. 1, a renewable energy storage system 100 according to the first embodiment stores renewable energy. The renewable energy storage system 100 includes a power generation device 1 as a renewable energy power generation means, a hydrogen production device 2 as a hydrogen production means, a buffer tank 3 responsible for high-purity hydrogen gas, and water as a hydrogenation means. A hydrogen production string 5 in which a plurality of hydrogen production apparatuses 2 are electrically connected in series, a hydrogen production array 6 in which a plurality of hydrogen production strings 5 are electrically connected in parallel, and hydrogen in the hydrogen production string 5 Switching means 7 for switching the number of serial production apparatuses 2 and the parallel number of hydrogen production strings 5 in the hydrogen production array 6, a control apparatus 8 for controlling the switching means 7, and hydrogen gas pipes connected to the hydrogen production apparatus 2 The backflow prevention mechanism 9 is provided at least before the joining point (position upstream from the joining point).

And the renewable energy storage system 100 which has such a structure is applied with respect to renewable energy.

Renewable energy represents, for example, renewable energy such as sunlight, wind power, geothermal power, and hydropower. In addition, renewable energy is not transported to the power generation apparatus 1 by electrical or physical connection lines, piping, or the like, but is based on global weather conditions. Specifically, when the renewable energy is, for example, sunlight, the power generation device 1 described later is, for example, a solar cell, a solar power generation system, or the like.

The power generation device 1 converts renewable energy such as sunlight and wind power into electric power. The power generation device 1 is electrically connected to the hydrogen production device 2 so that the power generated by the power generation device 1 can be supplied to the hydrogen production device 2.

The hydrogen production apparatus 2 produces hydrogen using the electric power obtained by the power generation apparatus 1 and / or the electric power stored in the power storage apparatus 12. Specifically, in the hydrogen production apparatus 2, at least hydrogen is generated by electrolyzing water (or an aqueous solution) using these electric powers. Therefore, the more electric power is supplied from the power generation device 1 and / or the power storage device 12 to the hydrogen production device 2, the more hydrogen is produced (generated) in the hydrogen production device 2. ing. The hydrogen production device 2 is electrically connected to the power generation device 1 and the power storage device 12, is connected to the buffer tank 3 through a gas pipe, and is connected to the temperature detector 16 through an electric signal line.

Although the specific configuration of the hydrogen production apparatus 2 is not particularly limited, the hydrogen production apparatus 2 supplies, for example, water, an electrolyte, an electrode catalyst for promoting a reaction provided so as to sandwich the electrolyte, and external power. An electrolysis cell holding a current collector or the like is provided. Then, water is electrolyzed by this electrode catalyst, and hydrogen and oxygen are generated. In the present invention, an electrolysis cell or an electrolysis stack in which electrolysis cells are laminated in multiple layers is defined as a hydrogen production apparatus 2.

The electrolyte is not particularly limited as long as at least hydrogen is generated by electrolysis, but a compound that exhibits alkalinity when dissolved in water, such as potassium hydroxide, is preferable. By using such a compound, the hydrogen production apparatus 2 that is inexpensive and hardly corrodes can be obtained. Further, as the electrolyte, for example, a solid polymer electrolyte such as Nafion (registered trademark) can be used.

The hydrogen production apparatus 2 configured as described above can be operated at a low temperature of 100 ° C. or lower, and has an advantage that it can be started in a short time.

Water electrolysis conditions are not particularly limited, and can be set arbitrarily as long as at least hydrogen can be generated. However, in order to increase the electrolytic efficiency, when the pressure during electrolysis (that is, during hydrogen production) is increased, the pressure resistance value of the backflow prevention mechanism 9 must be considered.

Although the specific configuration of the buffer tank 3 is not particularly limited, the purpose is to increase the purity of the hydrogen generated in the hydrogen production apparatus 2 by removing water from the hydrogen before being supplied to the hydrogenation apparatus 4 (described later). An apparatus for removing moisture is exemplified. For example, a gas-liquid separator or the like corresponds to this. The specific configuration of the gas-liquid separation device is not particularly limited, but for example, gas-liquid separation by cooling, a hydrogen separation membrane, or the like can be used, and it is preferable to use a hydrogen separation membrane. The removed water is circulated in the hydrogen production apparatus 2 and is electrolyzed.

And the hydrogen after moisture removal is supplied to the hydrogenation apparatus 4 connected by gas piping. Although the hydrogen after moisture removal may be directly supplied to the hydrogenation device 4, in the sixth embodiment shown in FIG. 6 (described later), this hydrogen is supplied to the water via the pressure regulator 19. By supplying to the adding device 4, the hydrogenation efficiency can be further increased, in other words, renewable energy can be stored without waste.

Although not shown in the embodiment shown in FIG. 1, this hydrogen can be temporarily stored in a hydrogen storage means such as a high-pressure tank. The specific configuration of the hydrogen gas hydrogen storage means is not particularly limited. For example, a known hydrogen cylinder, a pressure vessel for high pressure gas, or the like can be used. These may be used alone or in any combination of two or more. Examples of the material constituting the hydrogen storage means include, for example, a steel plate, a plastic reinforced with carbon fiber, and the like, and it is particularly preferable to use a pressure resistant container having a pressure higher than that applied to the hydrogen production apparatus 2.

Also, a hydrogen storage alloy can be used as the hydrogen storage means. Examples of the hydrogen storage alloy include an AB5 type alloy such as a rare earth metal-nickel system, and an alloy having a body-centered cubic (BCC) structure such as a titanium system or a chromium system. By making these hydrogen storage alloys exist in the above-mentioned container or the like, the hydrogen storage amount can be increased. Moreover, when storing the same volume of hydrogen, the pressure of the hydrogen storage means may be reduced.

The buffer tank 3 and the hydrogenation device 4 are preferably connected by a gas pipe (pipeline). However, these are not necessarily connected by gas pipes, and the produced hydrogen may be transported to the hydrogenation device 4 (that is, supplied to the hydrogenation device 4) using, for example, a high-pressure tank.

The hydrogenation device 4 adds hydrogen produced by the hydrogen production device 2 to unsaturated hydrocarbons. The hydrogenation device 4 is connected to the buffer tank 3 and the gas pipe as described above, and is connected to a saturated hydrocarbon storage tank 10 and an unsaturated hydrocarbon storage tank 11 (both described later) by a liquid pipe. Yes. Therefore, the unsaturated hydrocarbon is supplied from the unsaturated hydrocarbon storage tank 11 to the hydrogenation device 4.

Although the specific kind of unsaturated hydrocarbon used in the hydrogenation apparatus 4 is not particularly limited, for example, a liquid aromatic compound such as methylbenzene can be suitably used. For example, when methylbenzene is used as the unsaturated hydrocarbon, the resulting saturated hydrocarbon is methylcyclohexane, and the amount of hydrogen molecules that can be stored per mole of methylbenzene is 2.5 moles. However, depending on the conditions at the time of the addition reaction, for example, anthracene, phenanthrene, and the like may become liquid. When performing the addition reaction under such conditions, these aromatic compounds may be used. By using these aromatic compounds, more hydrogen can be stored.

Since such an aromatic compound is liquid at room temperature, it can be easily stored, and there is an advantage that a reaction interface becomes large when a hydrogenation reaction is performed. Further, by using an aromatic compound, the amount of hydrogen that can be added per molecule of the aromatic compound can be increased, and more hydrogen can be stored with a smaller amount of unsaturated hydrocarbons. In addition, 1 type may be used for unsaturated hydrocarbon and it may use 2 or more types by arbitrary ratios and combinations.

There is no particular limitation on the specific method for adding hydrogen to the unsaturated hydrocarbon in the hydrogenation apparatus 4. However, from the viewpoint of low cost and short reaction time, hydrogen is usually added to the unsaturated hydrocarbon using a catalyst. Examples of such a catalyst include metals such as Ni, Pd, Pt, Rh, Ir, Re, Ru, Mo, W, V, Os, Cr, Co, and Fe, and alloys thereof. The metal which comprises a catalyst, and those alloys may be used individually by 1 type, and may use 2 or more types by arbitrary ratios and combinations.

In addition, these catalysts are preferably finely divided from the viewpoint of further cost reduction by reducing the amount of catalyst and an increase in reaction surface area. When a finely divided catalyst is used, it may be supported on an arbitrary carrier from the viewpoint of preventing a reduction in surface area due to aggregation of the fine particle catalyst. When the catalyst is supported on the carrier, the method for supporting is not particularly limited, and for example, a coprecipitation method, a thermal decomposition method, an electroless plating method, or the like can be used. Also, the type of carrier is not particularly limited, and for example, in addition to carbon materials such as activated carbon, carbon nanotubes, and graphite, alumina silicate such as silica, alumina, and zeolite can be used. One type of carrier may be used, or two or more types may be used in any ratio and combination.

The hydrogenation reaction conditions for unsaturated hydrocarbons in the hydrogenation apparatus 4 are not particularly limited and may be set arbitrarily. For example, hydrogen can be added even at a reaction temperature of room temperature (about 25 ° C.), but it is preferable to add hydrogen at a temperature of about 100 ° C. to 400 ° C. from the viewpoint of shortening the reaction time.

In addition, although the reaction pressure during the addition reaction is not particularly limited, the pressure during hydrogen addition is 1 to 50 atm (gauge pressure) from the viewpoint of increasing the efficiency of the addition reaction and shortening the reaction time. That is, the pressure is preferably 0.1 MPa or more and 5 MPa or less. Therefore, in order to increase the pressure at the time of hydrogenation, the pressure regulator 19 shown in FIG. 6 can be provided between the buffer tank 3 and the hydrogenation device 4.

As described above, hydrogen can be added to the unsaturated hydrocarbon, and a saturated hydrocarbon is obtained. The obtained saturated hydrocarbon (so-called organic hydride) is stored in a saturated hydrocarbon storage tank 10 described later.

The hydrogen production string 5 has a configuration in which a plurality of hydrogen production apparatuses 2 are electrically connected in series via the switching means 7. Further, a configuration in which a plurality of the hydrogen production strings 5 are electrically connected in parallel via the switching means 7 is a hydrogen production array 6.

The switching means 7 has a function of supplying the electric power generated by the power generation device 1 to the hydrogen production device 2 or shutting it off from the hydrogen production device 2. The switching means 7 is a switching element that can control the driving state by an external signal, and may be a conventional switching element without particular limitation as long as the specification matches the power of the power generation means. For example, a relay element, a semiconductor element, etc. are mentioned.

Based on the device configuration determined by the signal processing unit 17 according to the power generation amount of the renewable energy power generation device 1, the electrical characteristics of the hydrogen production device 2, and the charging status of the power storage device 12, the control device 8 The device is not particularly limited as long as the device transmits an energization or cutoff signal. Depending on the situation, there may be a configuration in which a plurality of hydrogen production apparatuses 2 are connected in series, that is, one hydrogen production string configuration or a plurality of one hydrogen production apparatus 2 connected in parallel. The control device 8 is connected to the switching means 7 for transmitting an energization signal or a cut-off signal, and to the signal processing unit 17 for transmitting and receiving an electrical signal, respectively by electrical signal lines.

The backflow prevention mechanism 9 serves to prevent hydrogen gas produced by the operating hydrogen production apparatus 2 from flowing into the non-operated hydrogen production apparatus 2 through the gas pipe. This leads to prevention of leakage of hydrogen gas and failure or deterioration of the hydrogen production apparatus, in other words, an effect of highly efficient use of renewable energy can be expected. The backflow prevention mechanism 9 is not limited as long as the above purpose can be achieved, and examples thereof include a check valve and an on-off valve. Further, when the pressure is increased by the reaction pressure inside the hydrogen production apparatus, the internal pressure of the buffer tank 3, or the pressure regulator shown in FIG. 6, it is necessary to consider the pressure difference or the pressure resistance.

The installation position of the backflow prevention mechanism 9 is preferably provided immediately before the connection point of the pipe into which hydrogen gas flows toward the connection point between the hydrogen gas pipes (position upstream from the connection point). It does not have to be installed in the pipe on the side where it wants to flow (pipe downstream from the connection point). However, the configuration is not limited to the above as long as the hydrogen production apparatus 2 has a configuration or structure in which hydrogen gas does not flow into the non-operating hydrogen production apparatus 2 by switching the hydrogen production apparatus 2. For example, when a plurality of hydrogen production apparatuses 2 and the same number of buffer tanks 3 are connected in a one-to-one relationship, a backflow prevention mechanism is provided in a pipe until hydrogen gas is supplied to the hydrogenation apparatus 4. The form to provide is also considered. When a plurality of hydrogen production apparatuses 2 and one buffer tank 3 are connected, a backflow prevention mechanism may be provided in each pipe or at a connection point with the buffer tank 3. Since the pipe length can be long, there is a concern that the cost will increase.
<Operation>
The renewable energy storage system 100 according to the first embodiment has a configuration as described above. Next, the operation of each component of the renewable energy storage system 100 when storing renewable energy will be described with reference to FIG.

First, for example, using a renewable energy such as sunlight, the power generation device 1 (for example, a solar cell) generates electric power. The generated electric power is supplied to the hydrogen production array 6.

The electrical connection configuration of the serial number of the hydrogen production device 2 and / or the parallel number of the hydrogen production string 5 is switched according to the generated power and the electrical characteristics of the hydrogen production device 2. The hydrogen production array 6 starts electrolysis of water according to the supplied generated power and generates hydrogen while the electrical connection configuration of the hydrogen production apparatus 2 is switched.

Hydrogen produced in the hydrogen production array 6 is supplied to the buffer tank 3, and after purification such as moisture removal, it is purified and supplied to the hydrogenation device 4.

Here, the control device 8 and the switching means 7 are switched to the connection form of the number of water electrolysis means and the number of strings for obtaining the maximum hydrogen gas amount. At this time, in order to prevent the hydrogen gas produced by the hydrogen production apparatus 2 during operation from flowing into other hydrogen production apparatuses when it is not in operation or before the connection points of the pipes flowing into the respective gas pipe connection points (joining It is necessary to provide a backflow prevention mechanism at a position upstream of the point.

The environment in which the series of operations is performed is not particularly limited, and can be performed in any environment as long as the above-described problem can be solved. Moreover, it is not always necessary that all the components are installed in the same place. For example, the hydrogen production apparatus 2 can be installed in the room and the hydrogenation apparatus 4 can be installed in the room.
<Summary>
As described above, according to the renewable energy system 100 according to the first embodiment, it is possible to cope with fluctuations in the supply amount of renewable energy and to improve the efficiency of adding hydrogen to unsaturated hydrocarbons. Renewable energy can be stored without waste. And since the stored renewable energy is converted into hydrogen and stably stored as a compound containing the hydrogen, it can be freely used whenever necessary.
[2. Second Embodiment]
Next, a renewable energy storage system 200 according to the second embodiment will be described with reference to FIG. 2 that are denoted by the same reference numerals as those in FIG. 1 represent the same components, and detailed descriptions thereof are omitted.

In the renewable energy storage system 200, a saturated hydrocarbon storage tank 10 and an unsaturated hydrocarbon storage tank 11 are configured with respect to FIG.

The saturated hydrocarbon produced by adding hydrogen is accommodated in the saturated hydrocarbon storage tank 10 as described above. Then, the saturated hydrocarbons stored in the saturated hydrocarbon storage tank 10 are shipped in the liquid state to which the generated hydrogen is added. After shipment, hydrogen is desorbed from the saturated hydrocarbon, and the desorbed hydrogen is used as fuel or the like. Note that the unsaturated hydrocarbon generated by desorption of hydrogen is stored again in the unsaturated hydrocarbon storage tank 11.

The saturated hydrocarbon storage tank 10 stores the saturated hydrocarbon generated in the hydrogenation apparatus 4. Therefore, the saturated hydrocarbon storage tank 10 is connected to the hydrogenation device 4 by a liquid pipe. In addition, a device for controlling the supply amount of saturated hydrocarbons to the saturated hydrocarbon storage tank 10, for example, a flow adjustment valve, a flow meter, etc. is provided between the saturated hydrocarbon storage tank 10 and the hydrogenation device 4. Also good.

The unsaturated hydrocarbon storage tank 11 stores unsaturated hydrocarbons supplied to the hydrogenation device 4. The unsaturated hydrocarbon storage tank 11 is connected to the hydrogenation device 4 by a liquid pipe. Moreover, you may provide the apparatus for controlling the supply amount to the hydrogenation apparatus 4 from the unsaturated hydrocarbon storage tank 10, for example, a flow control valve, a flowmeter, etc.

Thus, the renewable energy storage system according to the second embodiment can also provide a system for storing renewable energy with high efficiency.
[3. Third Embodiment]
Next, a renewable energy storage system 300 according to the third embodiment will be described with reference to FIG. 3 that are denoted by the same reference numerals as those in FIG. 2 represent the same components, and detailed descriptions thereof are omitted.

When electric power is supplied to the hydrogen production array 6, water electrolysis starts and hydrogen is generated. However, electrolysis may not be performed only with the electric power from the power generator 1. In such a case, the power storage device 12 can be provided.

The power storage device 12 stores the power generated by the power generation device 1. The power storage device 12 is electrically connected to the power generation device 1 and the hydrogen production device 2 so that the power stored in the power storage device 12 can be supplied to the hydrogen production device 2 as necessary.

The specific configuration of the power storage device 12 is not particularly limited, and any known storage battery (secondary battery) and charge / discharge control system can be used. However, the storage battery is preferably a cycle storage battery manufactured exclusively for repeated use, in which the battery is discharged from a fully charged state and charged again after a certain discharge. Specifically, examples of the storage battery include a sodium sulfur battery and a lead storage battery, and among them, a lead storage battery that is excellent in electrical performance, compact, and inexpensive is preferable. In addition, a storage battery may be comprised by one storage battery, and may comprise two or more storage batteries arbitrarily, and may be comprised as a storage battery group. A conventional charge / discharge control system such as a battery charger can be applied to the charge / discharge control system, and there is no particular limitation.

By installing the power storage device 12 as described above in the renewable energy storage system configuration, the power from the power storage device 12 can be used together, or the power from the power generation device 1 is not used. You may use only. For example, since sufficient sunshine can be ensured during a clear daytime, the power storage device 12 is charged with a sufficient amount of power, and the hydrogenation device 4 is driven with surplus power. On the other hand, since the solar power generation cannot be performed during the night time, the hydrogenation device 4 is operated using the power charged in the power storage device 12 during the daytime. By doing in this way, renewable energy can be utilized without waste.

Thus, the renewable energy storage system according to the third embodiment can provide a system capable of storing renewable energy with high efficiency.
[4. Fourth Embodiment]
Next, a renewable energy storage system 400 according to the fourth embodiment will be described with reference to FIG. 4 that are denoted by the same reference numerals as those in FIG. 1 represent the same components, and a detailed description thereof will be omitted.

The renewable energy storage system 400 shown in FIG. 4 is similar to the renewable energy storage system 300 shown in FIG. 3 except that the output measuring instrument 13, the charging voltage measuring instrument 14, the current measuring instrument 15, the temperature measuring instrument 16, the signal processing unit 17, and the like. It is the structure which added. Even if the renewable energy storage system is configured in this manner, the problem of the present invention can be solved.

The output measuring instrument 13 is connected to the power generator 1, the signal processing unit 17, and an electric signal line. The output measuring instrument 13 is not limited as long as it has means for measuring the output voltage value and the output current value of the renewable energy power generation and has a function of giving the measured value to the signal processing unit 17 via the electric signal line.

The charging voltage measuring instrument 14 is connected to the charging device 12, the signal processing unit 17, and an electric signal line, and includes means for measuring the charging voltage of the storage battery. For example, there is no particular limitation as long as it has a function of supplying the signal processing unit 17 with a charging voltage signal of a charging / discharging control system inside the charging device 12.

The current measuring device 15 is a device that measures the current value flowing into the hydrogen production string 5. If there is a function to give a signal to the signal processing unit 17 connected by the electric signal line, there is no particular limitation. Further, for example, a method of measuring with a device such as a clamp meter without being incorporated in the electric circuit of the renewable energy power generation is conceivable.

The temperature measuring device 16 is a device that measures the reaction temperature inside the hydrogen production apparatus 2. A material having a function of giving a signal to the signal processing unit 17 connected by an electric signal line and having high measurement sensitivity of about −50 ° C. to 100 ° C. expected as a reaction temperature of the hydrogen production apparatus 2 is preferable.

The signal processing unit 17 is connected to the output measuring instrument 13, the charging voltage measuring instrument 14, the current measuring instrument 15, the temperature measuring instrument 16, and the control device 8 through electric signal lines. Based on the control program stored in the internal memory, the signal processing unit 17 reproduces according to the signal amount obtained by the output measuring instrument 13, the charging voltage measuring instrument 14, the current measuring instrument 15, and the temperature measuring instrument 16. It has a function of estimating (calculating) a hydrogen production array connection configuration capable of high-efficiency operation of a possible energy storage system, that is, obtaining a maximum hydrogen amount, and transmitting a control signal of each measuring instrument 13 to 16 to the control device 8. If there is, there is no particular limitation.

The estimation (calculation) of the device configuration takes into consideration the electrical characteristics of the hydrogen production device, particularly the rated operation value and the upper limit value, and then the output measuring device 13, the charging voltage measuring device 14, the current measuring device 15, and the temperature measuring device 16 signal. It is desirable to obtain the calculation and determine the connection configuration to be a system operation capable of producing hydrogen with high energy efficiency. However, frequent connection switching, such as when the input power fluctuation is severe, can cause failure and deterioration of the hydrogen production equipment, so avoid it as much as possible, and switch to a relaxed connection configuration to absorb renewable energy fluctuations. Renewable energy storage system can be operated with high efficiency.
[5. Fifth Embodiment]
Next, a renewable energy storage system 500 according to a fifth embodiment will be described with reference to FIG. 5 that are denoted by the same reference numerals as those in FIG. 4 represent the same components, and detailed descriptions thereof are omitted.

A renewable energy storage system 500 shown in FIG. 5 is obtained by adding a power regulator 18 to the renewable energy storage system 400 shown in FIG. Even if the renewable energy storage system is configured in this manner, the problem of the present invention can be solved.

∙ Depending on the type of renewable energy, the power obtained may be direct current or alternating current. For example, direct-current power can be obtained by solar power generation, and alternating-current power can be obtained by wind power generation. In addition, in solar power generation, output fluctuations associated with changes in solar radiation intensity are seen, and even DC power becomes fluctuating power accompanying changes over time. In wind power generation, the propeller rotates and the generator body rotates to output AC power. Since the power signals obtained by the power generation means are different in this way, a DC-DC converter converter or the like may be provided in solar power generation, and an AC-DC converter or the like that converts AC power into DC power is provided in wind power generation. There is a case.

Therefore, in the renewable energy storage system 500, the power adjustment device 18 having these functions is provided. Note that the renewable energy storage system 500 may be connected to the grid power via the power adjustment device 18. Even if the renewable energy storage system is configured in this manner, the problem of the present invention can be solved. Furthermore, since the power adjustment device 18 is provided, power can be supplied relatively stably, and renewable energy can be stored without imposing an excessive burden on the power storage device 12 and the hydrogen production device 2. .
[6. Sixth Embodiment]
Next, a renewable energy storage system 600 according to the sixth embodiment will be described with reference to FIG. 6 that are denoted by the same reference numerals as those in FIG. 5 represent the same components, and detailed descriptions thereof are omitted.

A renewable energy storage system 600 shown in FIG. 6 is obtained by adding a pressure regulator 19 to the renewable energy storage system 500 shown in FIG. Even if the renewable energy storage system is configured in this manner, the problem of the present invention can be solved.

The pressure adjusting device 19 can be connected between the buffer tank 3 and the hydrogenation device 4 via a fuel pipe. The pressure adjusting device 19 can increase the reaction efficiency of imparting hydrogen to the unsaturated hydrocarbon by increasing the pressure of the hydrogen gas purified in the buffer tank 3. In this way, the renewable energy storage system 600 can be operated with high efficiency.

The pressure adjusting device 19 is not particularly limited as long as the gas obtained from the buffer tank 3 can be supplied to the hydrogenation device 4 at a constant pressure. Examples of the pressure adjusting device 19 include a device that uses a method of containing hydrogen gas at a constant pressure. As a method for controlling the hydrogen pressure, for example, a pressure control means such as a known pressure regulator or compressor may be used. By providing such pressure control means, the pressure of the generated hydrogen can be appropriately controlled.
[7. Others]
In addition, although the apparatus structure was sequentially added and demonstrated on the basis of the renewable energy storage system 100, for example, only the power regulator 18 may be added to the renewable energy storage system 100, or only the pressure regulator 19 is used. May be added, and can be similarly applied to other embodiments. That is, the renewable energy storage system 100 includes a saturated hydrocarbon storage tank 10, an unsaturated hydrocarbon storage tank 11, a power storage device 12, an output measuring instrument 13, a charging voltage measuring instrument 14, a current measuring instrument 15, a temperature measuring instrument 16, One of the signal processing unit 17, the power regulator 18, and the pressure regulator 19 may be provided, or a plurality may be provided in combination.

Further, in the configuration of the hydrogen production string 5 of FIGS. 1 to 6 of the first to sixth embodiments, that is, the serial connection method of the hydrogen production apparatus 2, the hydrogen production apparatus 2 and the switching means 7 that are frequently used are energized. Therefore, there is a possibility that a difference in the usage frequency between the hydrogen production apparatus 2 and the hydrogen production apparatus 2 that is driven can be a cause of failure or early deterioration. In the first to sixth embodiments, these failures and deteriorations can be prevented by the connection method and the switching control in consideration of the use frequency.

Further, the renewable energy storage system according to the present invention does not necessarily correspond to one renewable energy power generation means. That is, it may be incorporated in a power distribution network such as a smart grid. When the renewable energy storage system according to the present invention is incorporated in a smart grid, it can provide a highly efficient use of renewable energy by converting surplus power and fluctuation power in the grid into saturated hydrocarbons.

Although not shown in FIGS. 1 to 6, the power regulator 18 and the power storage device 12 are controlled so as to equalize the fluctuation power, fluctuate-absorbed renewable energy efficient hydrogen production, and saturated hydrocarbons. By performing the generation, a highly efficient operation of the renewable energy storage system can be realized.

DESCRIPTION OF SYMBOLS 1 Power generation device, 2 Hydrogen production device, 3 Buffer tank, 4 Hydrogenation device, 5 Hydrogen production string, 6 Hydrogen production array, 7 Switching means, 8 Control device, 9 Backflow prevention mechanism, 10 Saturated hydrocarbon storage tank, 11 Discharge Saturated hydrocarbon storage tank, 12 power storage device, 13 output voltage measuring instrument, 14 charging voltage measuring instrument, 15 current measuring instrument, 16 temperature measuring instrument, 17 signal processing unit, 18 power regulator, 19 pressure regulator

Claims

A renewable energy storage system for storing renewable energy comprising:
Power generation means for converting the renewable energy into electrical energy;
Hydrogen production means comprising a plurality of hydrogen production devices for producing hydrogen gas using the electrical energy obtained by the power generation means;
A buffer tank for purifying the hydrogen gas produced by the hydrogen production means;
Hydrogenation means for adding hydrogen gas flowing out of the buffer tank to the unsaturated hydrocarbon;
Switching means for switching the connection configuration of the plurality of hydrogen production devices;
A control device for controlling the switching means,
A plurality of the hydrogen production apparatuses and the buffer tank are connected by a pipe having a backflow prevention mechanism,
The backflow prevention mechanism prevents a hydrogen gas produced by any one of the plurality of hydrogen production apparatuses from flowing into another hydrogen production apparatus through the pipe.
A renewable energy storage system for storing renewable energy comprising:
Power generation means for converting the renewable energy into electrical energy;
A plurality of hydrogen production strings in which a plurality of hydrogen production apparatuses that produce hydrogen gas using electric energy obtained by the power generation means are electrically connected in series, and a hydrogen production in which the plurality of hydrogen production strings are electrically connected in parallel. A hydrogen production means comprising an array;
A buffer tank for purifying the hydrogen gas produced by the hydrogen production means;
Hydrogenation means for adding hydrogen gas flowing out of the buffer tank to the unsaturated hydrocarbon;
Switching means for switching the number of serial connections of the plurality of hydrogen production devices constituting each of the plurality of hydrogen production strings and the number of parallel connections of the plurality of hydrogen production strings constituting the hydrogen production array;
A control device for controlling the switching means,
A plurality of the hydrogen production apparatuses and the buffer tank are connected by a pipe having a backflow prevention mechanism,
The backflow prevention mechanism prevents a hydrogen gas produced by any one of the plurality of hydrogen production apparatuses from flowing into another hydrogen production apparatus through the pipe.
In claim 2,
Saturated hydrogen storage means for storing saturated hydrocarbons produced by the hydrogenation means adding hydrogen gas to unsaturated hydrocarbons;
An unsaturated hydrocarbon storage means for storing the unsaturated hydrocarbon;
A renewable energy storage system further comprising:
2. The renewable energy storage system according to claim 1, further comprising a power storage device that stores electric power obtained by the power generation means.
In claim 4,
Output measuring means for detecting an output voltage value of the power generation means;
Charging voltage measuring means for detecting a charging voltage value of the power storage device;
Current measuring means for detecting the amount of current supplied to the hydrogen production means;
Temperature measuring means for detecting a reaction temperature inside the hydrogen producing means;
The detected output voltage value, the charging voltage value, the current amount and the reaction temperature are received, and the control signals of the output measuring means, the charging voltage measuring means, the current measuring means and the temperature measuring means are controlled. A signal processor for transmitting to the device;
A renewable energy storage system, further comprising:
In claim 4,
Further comprising power control means for controlling the output of power obtained by the power generation means,
The renewable energy storage system, wherein the power control means adjusts the amount of power supplied to the power storage device and the plurality of hydrogen production devices.
In claim 2,
A renewable energy storage system, further comprising a pressure adjusting device for adjusting the pressure of hydrogen gas flowing out of the buffer tank to the hydrogenation means.