JP2020045430A - Renewable energy utilization system - Google Patents

Abstract

To provide the renewable energy utilization system that can reduce a size of a facility, can effectively utilize oxygen obtained together with hydrogen from surplus power in a renewable energy power generation device, and further, can effectively utilize oxygen obtained together with hydrogen from the surplus power in a system.SOLUTION: The renewable energy utilization system comprises: a water electrolysis device 2 that generates hydrogen and oxygen using the surplus power of the renewable energy power generation device 1; and methanation equipment 3 for producing a hydrocarbon fuel such as methane by combining hydrogen produced in a water electrolysis device with carbon dioxide generated in the system. The system includes a biogasification facility 4 having an activated sludge tank 41, a fermentation tank 42, and a carbon dioxide separator 43 in the system, and the water electrolysis device supplies oxygen produced together with hydrogen to an activated sludge tank using the surplus power. The carbon dioxide separated by the carbon dioxide separator and the hydrogen obtained by the water electrolyzer are combined in the methanation equipment to produce the hydrocarbon fuel such as methane.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a renewable energy utilization system, and more specifically, synthesizes hydrogen produced using surplus power of a renewable energy power generation device and carbon dioxide generated during biogas generation or biomass power generation to produce methane. And the like.

  Generally, the power demand in the market is not constant, and for example, the power demand greatly changes between daytime and nighttime. For this reason, a distributed power source, which is a power source other than the power system, is arranged.When the power demand from the power system during the day is large, the power is actively supplied from the distributed power source to the power system, and the power demand of the power system at night is increased. Is smaller, the amount of power generated by the distributed power source is suppressed or the distributed power source is separated from the power system. The problem is how to effectively use surplus power as unused energy that cannot exhibit the original power generation potential due to the above-mentioned power generation limitation in a distributed power source. Attention has been focused on a method of converting gas into fuel (gas conversion) and storing and using it (so-called “Power to Gas”). A methanation technology for converting methane and the like that can be supplied to a city gas pipeline system as an energy supply infrastructure is being studied.

  For example, Patent Document 1 discloses an operation system of a distributed power supply 101 provided for the purpose of stable operation of a power system (A) as shown in FIG. Obtained from the surplus electric power by the hydrogen production means 102 including the water electrolysis apparatus, and the hydrogen obtained by the hydrogen production means 102 and the carbon dioxide separation / recovery apparatus 103 in the operation system and / or the carbon dioxide storage tank 104 outside the operation system. A hydrocarbon fuel producing means 105 for producing a hydrocarbon fuel such as methane, ethane, propane or butane from the obtained carbon dioxide; and a hydrocarbon fuel produced by the hydrocarbon fuel producing means 105 to a city gas pipe system (B). A distributed power supply operating system 100 comprising at least a hydrocarbon fuel injection means 106 for injection is described. Here, the distributed power source 101 includes at least a distributed power source that uses renewable energy, and the distributed power source 101 that uses renewable energy is a solar power generation device, a wind power generation device, a hydroelectric power generation device, a wave power generation device. It is described that the device is a device, a biomass power device, or a combination of two or more thereof.

  According to the operation system 100 of the distributed power supply, it is possible to effectively utilize surplus energy and recycle carbon dioxide while preventing a decrease in the operation rate of the facility, thereby reducing the environmental burden. In addition, the city gas pipeline system accepts the hydrocarbon fuel to be manufactured, and can be used continuously with a decentralized power source and gas consuming equipment, and also has a storage function. It is not necessary, and cost reduction as a facility can be realized.

JP 2009-77457 A

  However, the distributed power supply operation system 100 has the following problems. In other words, there is a problem that high-purity oxygen obtained together with hydrogen from the surplus power of the distributed power supply 101 by the hydrogen production means 102 including the water electrolysis device is not effectively utilized in the system in terms of cost. For example, it is also possible to provide a fuel cell as an auxiliary power supply in the system and use oxygen obtained from surplus power as fuel for the fuel cell when the power demand of the power system (A) is large (for example, see Japanese Unexamined Patent Application Publication No. However, in this case, the time when oxygen is produced from the surplus power of the distributed power source 101 is different from the time when oxygen is used as fuel for the fuel cell, so that the oxygen is temporarily stored. Storage means and the like are required, and the scale of the facility increases, which is not preferable in terms of cost.

  Also, among the distributed power sources 101 that use renewable energy, solar power generation devices, wind power generation devices, hydroelectric power generation devices, wave power generation devices, and the like vary in power amount depending on weather conditions such as weather and day and night. Therefore, there is a problem in that the surplus electric power becomes unstable, so that hydrocarbon fuel such as methane cannot be stably produced from the surplus electric power.

  The present invention has been made in order to solve the above-mentioned problems, and it is possible to stably produce a hydrocarbon fuel such as methane from surplus power of a renewable energy power generation device while reducing the size of the facility, and It is an object of the present invention to provide a renewable energy utilization system capable of effectively utilizing oxygen obtained together with hydrogen from electric power in the system.

In order to solve the above problem, a renewable energy utilization system according to the present invention has the following configuration.
(1) A water electrolysis device that produces hydrogen and oxygen using surplus power of a renewable energy power generation device, and methane or the like obtained by synthesizing hydrogen produced by the water electrolysis device and carbon dioxide generated in the system. A renewable energy utilization system comprising a methanation facility for producing a hydrocarbon fuel,
The system includes a biogasification facility having an activated sludge tank, a fermentation tank tank, and a carbon dioxide separation device,
The water electrolyzer uses the surplus power to produce oxygen together with hydrogen, supplying the activated sludge tank,
The method is characterized in that carbon dioxide separated by the carbon dioxide separator and hydrogen obtained by the water electrolyzer are synthesized by the methanation facility to produce a hydrocarbon fuel such as methane.

  In the present invention, the system is provided with a biogasification facility having an activated sludge layer, a fermentation tank, and a carbon dioxide separator, and the water electrolyzer uses the surplus power to produce oxygen produced together with hydrogen. Since the sludge is supplied to the tank, aerobic microorganisms contained in the sludge in the activated sludge tank actively decompose the sludge into organic substances, and the sludge containing the decomposed organic substances is anaerobically fermented in the fermentation tank tank. The generated methane (about 60%) and carbon dioxide (about 40%) are separated by a carbon dioxide separation device, so that CO2-free methane and carbon neutral carbon dioxide can be stably produced. Therefore, the oxygen produced by the water electrolysis device together with the hydrogen using the surplus electric power can be effectively used in the system. In particular, the oxygen produced by the water electrolysis apparatus is high in purity and has a higher oxygen partial pressure than air, so that the activity of aerobic microorganisms in the activated sludge tank can be enhanced to promote the decomposition of organic substances. In addition, with the above-mentioned high performance of the activated sludge tank, the sludge tank and its related devices can be made compact, and the sludge treatment time can be reduced.

  In addition, carbon dioxide separated by the carbon dioxide separator and hydrogen obtained by the water electrolyzer are synthesized in a methanation facility to produce a hydrocarbon fuel such as methane. Combined with the fuel and methane separated by the carbon dioxide separator, a hydrocarbon fuel such as methane with a low environmental load can be stably produced. In addition, oxygen obtained from the surplus electric power together with hydrogen by the water electrolyzer is supplied to the activated sludge tank of the biogasification facility, which eliminates the need for a storage means for temporarily storing oxygen and makes the facility compact. You can also.

  Therefore, according to the present invention, it is possible to stably produce a hydrocarbon fuel such as methane from surplus electric power of a renewable energy power generation device while reducing the size of the facility, and to convert oxygen obtained together with hydrogen from surplus electric power into a system. It is possible to provide a renewable energy utilization system that can be effectively used within a building.

(2) In the renewable energy utilization system described in (1),
The system includes a biomass power generation device that generates power by burning biofuel discharged from the biogasification facility, and a carbon dioxide separation and recovery device that separates and recovers carbon dioxide from exhaust gas of the biomass power generation device,
The method is characterized in that carbon dioxide separated and recovered by the carbon dioxide separation and recovery device and hydrogen obtained by the water electrolysis device are synthesized by the methanation facility to produce a hydrocarbon fuel such as methane.

  In the present invention, the system includes a biomass power generation device that generates power by burning biofuel discharged from the biogasification facility, and a carbon dioxide separation and recovery device that separates and recovers carbon dioxide from exhaust gas of the biomass power generation device. , The carbon dioxide separated and recovered by the carbon dioxide separation and recovery device and the hydrogen obtained by the water electrolysis device are synthesized in a methanation facility to produce a hydrocarbon fuel such as methane. In addition to methane and the like produced by synthesizing separated carbon dioxide and hydrogen obtained by a water electrolyzer in a methanation facility, biomass such as methane separated in a carbon dioxide separator in a biogasification facility Gas and organic matter remaining in the fermentation tank of the biogasification facility are converted into carbon dioxide from the exhaust gas of a biomass power generator that burns as biofuel. Obtain methane and the like produced by synthesizing carbon dioxide separated and recovered by the separation and recovery device with hydrogen obtained by the water electrolysis device in a methanation facility, and produce hydrocarbon fuel such as methane with low environmental load, More and more stable production is possible.

  In the carbon dioxide separation and capture device, for example, after the carbon dioxide in the exhaust gas of the biomass power generation device is chemically absorbed by the absorption solution composed of the amine solution, the carbon dioxide is separated and recovered from the absorption solution by heating. Can be obtained (chemical absorption method). The exhaust heat of the biomass power generation device may be used for the heating.

(3) A water electrolysis apparatus that produces hydrogen and oxygen using surplus power of a renewable energy power generation apparatus, and methane or the like obtained by synthesizing hydrogen produced by the water electrolysis apparatus and carbon dioxide generated in the system. A renewable energy utilization system comprising a methanation facility for producing a hydrocarbon fuel,
The system includes a biomass power generation device or a refuse power generation device, and a carbon dioxide separation / recovery device for separating and recovering carbon dioxide from exhaust gas of the biomass power generation device or the refuse power generation device,
The water electrolysis device produces oxygen together with hydrogen using the surplus power, supplying the biomass power generation device or a combustor of the garbage power generation device,
It is characterized in that carbon dioxide separated and recovered by the carbon dioxide separation and recovery apparatus and hydrogen obtained by the water electrolysis apparatus are synthesized by the methanation facility to produce a hydrocarbon fuel such as methane. . Here, the garbage power generation device means a device that generates power using garbage (waste) as an energy source, and the garbage (waste) includes industrial waste.

  In the present invention, the system includes a biomass power generation device or a waste power generation device, and a carbon dioxide separation / recovery device that separates and recovers carbon dioxide from exhaust gas of the biomass power generation device, and the water electrolysis device uses excess power to generate hydrogen. The oxygen produced together with the biomass power generator or refuse power generator is supplied to the combustor, so that the combustion temperature of the biomass power generator or refuse power generator can be improved and the combustion can be improved. Generation can be easily suppressed. Therefore, oxygen obtained together with hydrogen from surplus power can be effectively used in the system.

  In addition, carbon dioxide separated and recovered by a carbon dioxide separation and recovery device from the exhaust gas of a biomass power generation device or a garbage power generation device and hydrogen obtained by a water electrolysis device are synthesized in a methanation facility to produce hydrocarbons such as methane. Since the fuel is manufactured, the carbon dioxide separated and captured by the carbon dioxide separation and capture device from the exhaust gas of the biomass power generator or garbage power generator that can be operated continuously without being affected by the weather conditions such as weather and day and night is stabilized. As a result, a hydrocarbon fuel such as methane can be stably produced. The oxygen obtained from the surplus electric power together with the hydrogen by the water electrolyzer is supplied to the combustor of the biomass power generator or the garbage power generator, so that storage means for temporarily storing oxygen is not required, and the facility is compact. It can also be converted.

  Therefore, according to the present invention, it is possible to stably produce a hydrocarbon fuel such as methane from surplus electric power of a renewable energy power generation device while reducing the size of the facility, and to convert oxygen obtained together with hydrogen from surplus electric power into a system. It is possible to provide a renewable energy utilization system that can be effectively used within a building.

(4) In the renewable energy utilization system described in (2) or (3),
A surplus electric power is selectively supplied to the water electrolysis device from the renewable energy power generation device, the biomass power generation device, or the waste power generation device.

  In the present invention, the water electrolysis device selectively supplies surplus power from a renewable energy power generation device, a biomass power generation device, or a garbage power generation device. Can be used to produce hydrogen and oxygen, and a more stable and inexpensive hydrocarbon fuel such as methane can be produced.

  For example, when the renewable energy power generation device is any one of a solar power generation device, a wind power generation device, a hydroelectric power generation device, a wave power generation device, or a combination thereof, the amount of power may be changed depending on weather conditions such as season or day and night. It is easy to fluctuate, and the power cost of the surplus power is also likely to fluctuate. However, biomass power generation equipment or garbage power generation equipment generally uses sewage, household garbage, industrial waste, and the like as raw materials, so the amount of power generation is hardly affected by weather conditions such as seasonal or day and night, and the surplus power is stable. The situation is easy to obtain.

  Therefore, the destination of the surplus power to the water electrolysis device, the surplus of the surplus power, by making it possible to select based on the level of the power cost, etc., the surplus power to the water electrolysis device more stably, Also, it can be supplied at low cost. As a result, hydrocarbon fuel such as methane can be more stably manufactured at low cost. Further, by stably supplying the surplus power, the operation rate of the water electrolysis device that utilizes the surplus power can be improved, and the economics of “power-to-gas” can be improved.

(5) In the renewable energy utilization system described in (4),
The renewable energy power generation device is a photovoltaic power generation device, the water electrolysis device supplies surplus power during the day from the photovoltaic power generation device, and the surplus power during the night from the biomass power generation device or the garbage power generation device. Is supplied.

  In the present invention, the renewable energy power generation device is a photovoltaic power generation device, and the water electrolysis device is supplied with surplus power during the day from the photovoltaic power generation device, and the surplus power at night is supplied from the biomass power generation device or the garbage power generation device. Therefore, surplus power can be stably supplied to the water electrolysis device day and night. Therefore, surplus electric power can be supplied to the water electrolysis device more stably and at low cost, and a more stable and inexpensive hydrocarbon fuel such as methane can be produced.

(6) In the renewable energy utilization system described in (4) or (5),
The biomass power generation device or the refuse power generation device is arranged in the same premises as the water electrolysis device.

  In the present invention, the biomass power generation device or the refuse power generation device is disposed in the same premises as the water electrolysis device, so that when supplying surplus power to the water electrolysis device, there is no need to pass through an off-site power system. Therefore, surplus power can be supplied to the water electrolysis device more easily and at lower cost, and a more stable and inexpensive hydrocarbon fuel such as methane can be produced.

(7) In the renewable energy utilization system according to any one of (2) to (6),
A part of a hydrocarbon fuel such as methane produced in the methanation facility is supplied to the biomass power generation device or the refuse power generation device as a fuel for auxiliary combustion.

  In the present invention, a part of the hydrocarbon fuel such as methane produced by the methanation facility is supplied to the biomass power generation device or the garbage power generation device as an auxiliary fuel, so that the hydrocarbon fuel such as CO2-free methane is supplied. By utilizing in the system, the carbon dioxide emission coefficient at the time of power generation in the biomass power generation device or the garbage power generation device can be further reduced, and a renewable energy utilization system with even less environmental load can be realized.

  According to the present invention, it is possible to stably produce a hydrocarbon fuel such as methane from surplus power of a renewable energy power generation device while reducing the size of the facility, and to obtain oxygen obtained together with hydrogen from surplus power in the system. A renewable energy utilization system that can be used effectively can be provided.

It is a system configuration conceptual diagram in the renewable energy utilization system of the 1st example which concerns on this embodiment. It is a system configuration conceptual diagram in the renewable energy utilization system of the 2nd example which concerns on this embodiment. It is a system configuration conceptual diagram in the renewable energy utilization system of the 3rd example which concerns on this embodiment. FIG. 1 is a schematic configuration diagram of an operation system of a distributed power supply described in Patent Literature 1.

  Next, a renewable energy utilization system according to an embodiment of the present invention will be described in detail with reference to the drawings. Hereinafter, system configurations of the first to third embodiments of the present renewable energy utilization system will be described in detail, and an operation method thereof will be described.

<Configuration and operation method of this renewable energy utilization system>
The system configurations and operation methods of the first to third examples of the renewable energy utilization system according to the present embodiment will be described with reference to FIGS. FIG. 1 shows a system configuration conceptual diagram of a renewable energy utilization system of a first example according to the present embodiment. FIG. 2 shows a conceptual diagram of a system configuration in a renewable energy utilization system of a second example according to the present embodiment. FIG. 3 shows a conceptual diagram of a system configuration in a renewable energy utilization system of a third example according to the present embodiment.

(First embodiment)
As shown in FIG. 1, a renewable energy utilization system 10 in the first embodiment includes a water electrolysis device 2 that produces hydrogen and oxygen using surplus power of a renewable energy power generation device 1, and a water electrolysis device 2. This is a renewable energy utilization system including a methanation facility 3 for synthesizing hydrogen produced by the above and carbon dioxide generated in the system to produce a hydrocarbon fuel such as methane.

  Here, the renewable energy power generation device 1 corresponds to a solar power generation device, a wind power generation device, a hydroelectric power generation device, a wave power generation device, a geothermal power generation device, a biomass power generation device, or the like. Combinations of two or more are also included. The surplus power is the unused power obtained by subtracting the power supplied to the power system or the like from the power generated by the renewable energy power generation device 1, or the renewable energy when the supply to the power system or the like is stopped. This is the power generated by the power generation device 1. The water electrolysis device 2 is a device for producing hydrogen and oxygen by electrolyzing water or water vapor, and includes an alkaline water electrolysis cell, a solid polymer electrolysis cell, a solid oxide electrolysis cell (SOEC), and the like. Applicable. The methanation facility 3 is a facility for synthesizing hydrogen and carbon dioxide (including the case where it is used after being reduced to carbon monoxide) to produce a hydrocarbon fuel such as methane, ethane, propane, and butane. .

  In addition, the present system includes a biogasification facility 4 having an activated sludge tank 41, a fermentation tank tank 42, and a carbon dioxide separator 43, and the water electrolyzer 2 uses excess power to produce oxygen produced together with hydrogen. It is supplied to the activated sludge tank 41. The biogasification facility 4 can stably produce CO2-free methane and carbon-neutral carbon dioxide in the following process.

  That is, in the activated sludge tank 41, activated sludge (a mud containing a large amount of aerobic microorganisms) is added to the sewage sent from a sewer or the like, and the pure oxygen produced by the water electrolysis device 2 using the surplus electric power is converted into the sewage. And aeration. Since the oxygen concentration of the gas to be aerated is high, the aerobic microorganisms contained in the activated sludge are activated by the high concentration of oxygen, and the sludge is actively decomposed into organic substances (degradable organic substances that are difficult to decompose). Sludge rich in organic matter becomes spongy and precipitates. After the organic matter is concentrated by reducing the water content of the settled sludge, the sludge is put into the fermentation tank 42. In the fermentation tank 42, anaerobic microorganisms ferment organic matter to produce methane (about 60%) and carbon dioxide (about 40%). Methane and carbon dioxide generated in the fermentation tank 42 are separated by the carbon dioxide separator 43, so that CO2-free methane and carbon-neutral carbon dioxide can be stably produced. The carbon dioxide separation device 43 includes, for example, a device that uses activated carbon as an adsorbent and uses a method of separating methane and carbon dioxide using a difference in adsorption speed.

  Further, carbon dioxide separated by the carbon dioxide separator 43 of the biogasification facility 4 and hydrogen obtained by the water electrolysis apparatus 2 are synthesized by the methanation facility 3 to produce a hydrocarbon fuel such as methane. I do. Together with the hydrocarbon fuel such as methane and the methane separated by the carbon dioxide separator 43, it is possible to stably produce a hydrocarbon fuel such as methane with low environmental load. In this system, the oxygen obtained from the surplus electric power together with the hydrogen by the water electrolyzer 2 is supplied to the activated sludge tank 41 of the biogasification facility 4, so that storage means for temporarily storing oxygen is not required. In addition, the size of the facility can be reduced.

(Second embodiment)
As shown in FIG. 2, the renewable energy utilization system 10B in the second embodiment includes a water electrolysis device 2B that produces hydrogen and oxygen using surplus power of the renewable energy power generation device 1B, and a water electrolysis device 2B. This is a renewable energy utilization system including a methanation facility 3B that synthesizes hydrogen produced by the above and carbon dioxide generated in the system to produce a hydrocarbon fuel such as methane.

  Here, the renewable energy power generation device 1B corresponds to a solar power generation device, a wind power generation device, a hydroelectric power generation device, a wave power generation device, a geothermal power generation device, a biomass power generation device, or the like. Combinations of two or more are also included. The surplus power is the unused power obtained by subtracting the power supplied to the power system or other supply destination from the power generated by the renewable energy power generation device 1B, or the renewable energy when the supply to the power system or the like is stopped. This is the power generated by the power generation device 1B. The water electrolysis device 2B is a device for producing hydrogen and oxygen by electrolyzing water or water vapor, and includes an alkaline water electrolysis cell, a solid polymer electrolysis cell, a solid oxide electrolysis cell (SOEC), and the like. Applicable. In addition, the methanation facility 3B is a facility that synthesizes hydrogen and carbon dioxide (including the case where it is used after being reduced to carbon monoxide) to produce a hydrocarbon fuel such as methane, ethane, propane, and butane. .

  Further, in the present system 10B, in addition to the biogasification equipment 4B having the activated sludge tank 41B, the fermentation tank tank 42B, and the carbon dioxide separation device 43B, the biofuel discharged from the biogasification equipment 4B is burned. It is provided with a biomass power generation device 5B for generating electricity, and a carbon dioxide separation and recovery device 6B for separating and recovering carbon dioxide from exhaust gas of the biomass power generation device 5B. The carbon dioxide separated and recovered by the carbon dioxide separation and recovery device 6B and the water electrolysis device 2B And hydrogen produced by the method described above is synthesized in a methanation facility 3B to produce a hydrocarbon fuel such as methane. In the present system 10B, by adding a biomass power generation device 5B and a carbon dioxide separation / recovery device 6B, carbon neutral carbon dioxide is stably produced from biofuel such as CO2-free methane in the following process. be able to.

  That is, in the biogasification facility 4B, biogas such as CO2-free methane separated by the carbon dioxide separation device 43B and organic matter (biomass resources) remaining as a residue in the fermentation tank 42B are discharged as biofuel. The biomass power generation device 5B sends, for example, a combustion gas obtained by burning biogas at a high temperature and a high pressure to a gas turbine to rotate the gas turbine to generate power, or directly burns organic matter (biomass resources) in a combustor and heats the combustor. The steam turbine is rotated by using the steam heated in the step to generate power. Exhaust gas (combustion gas) when the biomass power generation device 5B burns biofuel is separated and collected into carbon dioxide by the carbon dioxide separation and collection device 6B, and is discharged. This carbon dioxide becomes a raw material from biomass resources derived from living organisms and absorbs carbon dioxide during the growth process of living organisms, so that absorption and emission are offset and treated as carbon neutral carbon dioxide. Therefore, carbon-neutral carbon dioxide can be stably produced from CO2-free methane or the like.

  Further, carbon dioxide separated and recovered by the carbon dioxide separation and recovery device 6B and hydrogen obtained by the water electrolysis device 2B are synthesized by the methanation equipment 3B to produce a hydrocarbon fuel such as methane. If the methane separated by the carbon dioxide separation device 43B is not burned as biofuel in the biomass power generation device 5B, the hydrocarbon fuel such as methane is combined with the methane to reduce the environmental load of the methane or other hydrocarbon fuel. Fuel can be manufactured stably.

  Further, surplus power may be selectively supplied to the water electrolysis device 2B from the renewable energy power generation device 1B or the biomass power generation device 5B. In this case, the surplus power of the renewable energy power generation device 1B and the biomass power generation device 5B is set so that the water electrolysis device 2B can produce hydrogen and oxygen using surplus power that is advantageous in terms of quantity and cost. It is preferable to provide a surplus power monitoring device 8B for monitoring the surplus power. For example, the surplus power monitoring device 8B is configured to generate a surplus power for the water electrolysis device 2B from among the plurality of renewable energy power generation devices 1B and the biomass power generation devices 5B in the system based on the surplus power level and the power cost. By selecting a power supply destination, surplus power can be supplied to the water electrolysis device 2B more stably and at low cost.

  Further, the renewable energy power generation device 1B is a solar power generation device 1Ba, and supplies the water electrolysis device 2B with surplus power during the day from the solar power generation device 1Ba and supplies surplus power during the night from the biomass power generation device 5B. You may. In this case, surplus power can be stably supplied to the water electrolysis device 2B day and night. That is, in the photovoltaic power generator 1Ba, a large amount of surplus power can be generated in the daytime, so that the surplus power can be supplied to the water electrolysis device 2B more stably and at low cost. On the other hand, at night, the amount of power generated by the photovoltaic power generation device 1Ba becomes zero, so that surplus power is supplied to the water electrolysis device 2B from the biomass power generation device 5B that can generate power regardless of day and night. This makes it possible to produce a more stable and inexpensive hydrocarbon fuel such as methane.

  Further, the biomass power generation device 5B may be arranged in the same premises as the water electrolysis device 2B. In this case, when supplying the surplus power of the biomass power generation device 5B to the water electrolysis device 2B, the surplus power can be supplied to the water electrolysis device 2B more easily and at low cost without having to go through an off-site power system. A more stable and cheaper hydrocarbon fuel such as methane can be produced.

  Further, a part of a hydrocarbon fuel such as methane produced by the methanation facility 3B may be supplied to the biomass power generation device 5B as a fuel for supporting combustion. In this case, by utilizing a CO2-free hydrocarbon fuel such as methane in the system, the carbon dioxide emission coefficient at the time of power generation in the biomass power generation device 5B is further reduced, and the renewable energy utilization system 10B with even less environmental load is used. Can be realized.

  In the present system 10B, oxygen obtained from the surplus electric power together with the hydrogen by the water electrolysis device 2B is supplied to the activated sludge tank 41B of the biogasification facility 4B, so that storage means for temporarily storing oxygen is not required. Thus, the size of the facility can be reduced. The CO2-free hydrogen produced by the water electrolysis device 2B may be stored in the hydrogen storage alloy 7B and supplied to the methanation facility 3B from the hydrogen storage alloy 7B. The hydrogen storage alloy 7B can store the hydrogen at a density twice as high as that in the case where it is stored in liquid hydrogen, and can have a more compact system configuration. Further, the hydrogen storage alloy 7B needs to be heated when discharging hydrogen. However, if the exhaust heat when generating methane by the methanation equipment 3B is used, it is not necessary to newly add a heating device.

(Third embodiment)
As shown in FIG. 3, a renewable energy utilization system 10C in the third embodiment includes a water electrolysis device 2C that produces hydrogen and oxygen using surplus power of a renewable energy power generation device 1C, and a water electrolysis device 2C. This is a renewable energy utilization system including a methanation facility 3C that synthesizes hydrogen produced by the above and carbon dioxide generated in the system to produce a hydrocarbon fuel such as methane.

  Here, the renewable energy power generation device 1C includes a solar power generation device, a wind power generation device, a hydroelectric power generation device, a wave power generation device, a geothermal power generation device, a biomass power generation device, and the like. Combinations of two or more are also included. In addition, surplus power is unused power obtained by subtracting power supplied to a supply destination such as a power system from power generated by the renewable energy power generation device 1C, or renewable energy when supply to the power system or the like is stopped. This is the power generated by the power generation device 1C. The water electrolysis apparatus 2C is an apparatus for producing hydrogen and oxygen by electrolyzing water or water vapor, and includes an alkaline water electrolysis cell, a solid polymer electrolysis cell, a solid oxide electrolysis cell (SOEC), and the like. Applicable. In addition, the methanation facility 3C is a facility that synthesizes hydrogen and carbon dioxide (including the case where it is used after being reduced to carbon monoxide) to produce hydrocarbon fuel such as methane, ethane, propane, and butane. .

  Further, the present system 10C includes a biomass power generation device or refuse power generation device 5C, and a carbon dioxide separation and recovery device 6C for separating and recovering carbon dioxide from exhaust gas of the biomass power generation device or refuse power generation device 5C. Supplies oxygen produced together with hydrogen using surplus power to the combustor of the biomass power generation device or the waste power generation device 5C. In this case, the biomass resource or the refuse resource is burned at a higher temperature in the combustor of the biomass power generation device or the refuse power generation device 5C. That is, it is possible to improve the combustion such as increasing the combustion temperature in the combustor of the biomass power generation device or the refuse power generation device 5C, and it is possible to easily suppress the generation of harmful substances such as dioxin. Therefore, oxygen obtained together with hydrogen from surplus power can be effectively used in the system.

  Here, the biomass power generation device or the garbage power generation device 5C includes a direct combustion system in which bioresources such as thinned wood and combustible waste and industrial waste resources are directly burned by a combustor to generate power by turning a steam turbine, The pyrolysis gas generated by heating bio-resources such as thinned wood and combustible waste and industrial waste resources is burned at high temperature and high pressure in a combustor and sent to a gas turbine to turn the gas turbine to generate electricity. Pyrolysis gasification method, fermenting bioresources such as animal manure and sewage sludge to generate biogas such as methane, and sending the combustion gas, which has been burned at high temperature and high pressure in a combustor, to a gas turbine and rotating the gas turbine There is a biochemical gasification system for generating electric power by using any method, and any of them may be used.

  In addition, carbon dioxide separated and recovered by the carbon dioxide separation and recovery device 6C from the exhaust gas of the biomass power generation device or the waste power generation device 5C and hydrogen obtained by the water electrolysis device 2C are synthesized in the methanation facility 3C, and methane is produced. And other hydrocarbon fuels. In this case, the carbon dioxide separated and recovered by the carbon dioxide separation and recovery device 6C from the exhaust gas of the biomass power generation device or the garbage power generation device 5C that is hardly affected by weather conditions such as the weather and day and night can be continuously operated. As a result, a hydrocarbon fuel such as methane can be stably produced.

  Further, surplus power may be selectively supplied to the water electrolysis device 2C from the renewable energy power generation device 1C or the biomass power generation device or the waste power generation device 5C. In this case, the renewable energy power generation device 1C and the biomass power generation device or the waste power generation device 5C have a surplus so that the water electrolysis device 2C can produce hydrogen and oxygen using surplus power that is advantageous in terms of quantity and cost. It is preferable to provide a surplus power monitoring device 8C for monitoring the remaining power. For example, the surplus power monitoring device 8C may perform water electrolysis on the basis of surplus power surplus, power cost, etc., from among a plurality of renewable energy power generation devices 1C, a biomass power generation device in the system, or a waste power generation device 5C. By selecting the supply destination of the surplus power to the device 2C, the surplus power can be supplied to the water electrolysis device 2C more stably and at low cost.

  In addition, the renewable energy power generation device 1C is a solar power generation device 1Ca, and the water electrolysis device 2C is supplied with surplus power during the day from the solar power generation device 1Ca, and is supplied from the biomass power generation device or the garbage power generation device 5C at night. Surplus power may be supplied. In this case, surplus power can be stably supplied to the water electrolysis device 2C day and night. That is, in the photovoltaic power generation device 1Ca, a large amount of surplus power can be generated in the daytime, so that the surplus power can be supplied to the water electrolysis device 2C more stably and at low cost. On the other hand, at night, the amount of power generated by the solar power generation device 1Ca becomes zero, so that surplus power is supplied to the water electrolysis device 2C from the biomass power generation device or the waste power generation device 5C that can generate power regardless of day and night. This makes it possible to produce a more stable and inexpensive hydrocarbon fuel such as methane.

  Further, the biomass power generation device or the waste power generation device 5C may be disposed in the same premises as the water electrolysis device 2C. In this case, when supplying the surplus power of the biomass power generation device or the waste power generation device 5C to the water electrolysis device 2C, there is no need to pass through an off-site power system, and the surplus power is supplied to the water electrolysis device 2C more easily and at low cost. It is possible to supply more stable and cheap hydrocarbon fuel such as methane.

  Further, a part of a hydrocarbon fuel such as methane produced in the methanation facility 3C may be supplied to the biomass power generation device or the waste power generation device 5C as a fuel for auxiliary combustion. In this case, by utilizing a hydrocarbon fuel such as CO2-free methane in the system, the carbon dioxide emission coefficient at the time of power generation in the biomass power generation device or the garbage power generation device 5C can be further reduced, and renewable with less environmental load. An energy utilization system 10C can be realized.

  In the present system 10C, the oxygen obtained from the surplus electric power together with the hydrogen by the water electrolysis device 2C is supplied to the combustor of the biomass power generation device or the refuse power generation device 5C. This is unnecessary, and the size of the facility can be reduced. The CO2-free hydrogen produced by the water electrolysis device 2C may be stored in the hydrogen storage alloy 7C and supplied to the methanation facility 3C from the hydrogen storage alloy 7C. The hydrogen storage alloy 7 </ b> C can store the hydrogen at a density twice as high as that in the case of storing it with liquid hydrogen, and can have a more compact system configuration. Further, the hydrogen storage alloy 7C needs to be heated when discharging hydrogen. However, if the exhaust heat when methane is generated by the methanation facility 3C is used, it is not necessary to newly add a heating device.

<Effects>
As described above in detail, according to the renewable energy utilization systems 10 and 10B according to the present embodiment, the activated sludge tanks 41 and 41B, the fermentation tanks 42 and 42B, and the carbon dioxide separation device 43 are provided in the system. , 43B, and the water electrolyzers 2 and 2B supply oxygen produced together with hydrogen using the surplus power to the activated sludge tanks 41 and 41B. Aerobic microorganisms contained in the sludge of 41B actively decompose the sludge into organic matter, and methane produced by anaerobic fermentation of the sludge rich in decomposed organic matter in the fermentation tanks 42 and 42B (about 60%) and carbon dioxide (about 40%) are separated by the carbon dioxide separators 43 and 43B to stably produce CO2-free methane and carbon-neutral carbon dioxide. It is possible. Therefore, the oxygen produced by the water electrolysis devices 2 and 2B together with the hydrogen using the surplus electric power can be effectively used in the system. In particular, since the oxygen produced by the water electrolyzers 2 and 2B is high in purity and has a higher oxygen partial pressure than air, the activity of aerobic microorganisms in the activated sludge tanks 41 and 41B is increased to decompose organic substances. Can be promoted. Further, with the above-mentioned high performance of the activated sludge tanks 41 and 41B, the sludge tank and its related devices can be made compact, and the sludge treatment time can be reduced.

  In addition, carbon dioxide separated by the carbon dioxide separators 43 and 43B and hydrogen obtained by the water electrolyzers 2 and 2B are synthesized in the methanation facilities 3 and 3B to produce a hydrocarbon fuel such as methane. Therefore, it is possible to stably produce a hydrocarbon fuel such as methane with a low environmental load, in combination with the hydrocarbon fuel such as methane and the methane separated by the carbon dioxide separation devices 43 and 43B. The oxygen obtained from the surplus electric power together with the hydrogen by the water electrolyzers 2 and 2B is supplied to the activated sludge tanks 41 and 41B of the biogasification facilities 4 and 4B. This is unnecessary, and the size of the facility can be reduced.

  Therefore, according to the present embodiment, it is possible to stably produce hydrocarbon fuel such as methane from the surplus power of the renewable energy power generation devices 1 and 1B while reducing the size of the facility, and obtain hydrogen fuel from the surplus power together with hydrogen. It is possible to provide the renewable energy utilization systems 10 and 10B that can effectively utilize oxygen in the system.

  Further, according to the present embodiment, in the system, a biomass power generation device 5B for generating electricity by burning biofuel discharged from the biogasification facility 4B and a carbon dioxide for separating and recovering carbon dioxide from exhaust gas of the biomass power generation device 5B are provided. A carbon separation / recovery device 6B, wherein the carbon dioxide separated and recovered by the carbon dioxide separation / recovery device 6B and the hydrogen obtained by the water electrolysis device 2B are synthesized by a methanation facility 3B to produce a hydrocarbon fuel such as methane. Is produced. In addition to methane produced by synthesizing carbon dioxide separated by the carbon dioxide separator 43B and hydrogen obtained by the water electrolyzer 2B in the methanation facility 3B, a biogasification facility Biogas such as methane separated by the carbon dioxide separator 43B of 4B, and organic remaining in the fermentation tank 42B of the biogasification facility 4B. And the like, and the carbon dioxide separated and recovered by the carbon dioxide separation and recovery device 6B from the exhaust gas of the biomass power generation device 5B burning as biofuel and the hydrogen obtained by the water electrolysis device 2B are synthesized by the methanation equipment 3B. By obtaining the produced methane and the like, it is possible to produce more and more stably a hydrocarbon fuel such as methane with a low environmental load.

  In the carbon dioxide separation / recovery device 6B, for example, after carbon dioxide in the exhaust gas of the biomass power generation device 5B is chemically absorbed in an absorbent composed of an amine solution, the carbon dioxide is separated and recovered from the absorbent by heating. (Chemical absorption method). The exhaust heat of the biomass power generator 5B may be used for the heating.

  Further, according to the present embodiment, the system includes the biomass power generation device or refuse power generation device 5C, and the carbon dioxide separation / recovery device 6C for separating and recovering carbon dioxide from the exhaust gas of the biomass power generation device or refuse power generation device 5C. Since the oxygen produced by the water electrolysis device 2C together with the hydrogen using the surplus power is supplied to the combustor of the biomass power generation device or the waste power generation device 5C, the combustion temperature of the biomass power generation device or the waste power generation device 5C is improved. Combustion can be improved, and for example, generation of harmful substances such as dioxin can be easily suppressed. Therefore, oxygen obtained together with hydrogen from surplus power can be effectively used in the system.

  In addition, carbon dioxide separated and recovered by the carbon dioxide separation and recovery device 6C from the exhaust gas of the biomass power generation device or the waste power generation device 5C and hydrogen obtained by the water electrolysis device 2C are synthesized in the methanation facility 3C, and methane is produced. Since it produces hydrocarbon fuels, such as the biomass power generator or the garbage power generator 5C that can be operated continuously without being affected by weather conditions such as weather and day and night, it is separated and recovered by the carbon dioxide separation and recovery device 6C. Carbon dioxide can be stably obtained, and as a result, a hydrocarbon fuel such as methane can be stably produced. The oxygen obtained from the surplus electric power together with the hydrogen by the water electrolysis device 2C is supplied to the combustor of the biomass power generation device or the refuse power generation device 5C, so that storage means for temporarily storing oxygen is not required, and the scale of the facility is reduced. Can be made more compact.

  Therefore, according to the present embodiment, it is possible to stably produce a hydrocarbon fuel such as methane from the surplus power of the renewable energy power generation device 1C while reducing the size of the facility, and to obtain oxygen obtained together with hydrogen from the surplus power. , A renewable energy utilization system 10C that can be effectively used in the system can be provided.

  Further, according to the present embodiment, since the surplus power is selectively supplied to the water electrolysis devices 2B and 2C from the renewable energy power generation devices 1B and 1C or the biomass power generation devices 5B and 5C or the waste power generation device 5C. The electrolyzers 2B and 2C can produce hydrogen and oxygen using surplus electric power that is advantageous in terms of quantity and cost, and can produce more stable and inexpensive hydrocarbon fuel such as methane.

  For example, when the renewable energy power generation devices 1B and 1C are any of a solar power generation device, a wind power generation device, a hydroelectric power generation device, and a wave power generation device, or a combination thereof, depending on weather conditions such as season or day and night, The power amount tends to fluctuate, and the power cost of the surplus power tends to fluctuate. However, since the biomass power generators 5B and 5C or the garbage power generator 5C generally use sewage, household garbage, industrial waste, or the like as a raw material, the amount of power generation is hardly affected by weather conditions such as seasons or day and night. Is also stable and easy to obtain.

  Therefore, the surplus power to the water electrolysis devices 2B and 2C can be selected based on the surplus of the surplus power and the level of the power cost, etc., so that the surplus power to the water electrolysis devices 2B and 2C can be selected. It can be supplied more stably and at low cost. As a result, hydrocarbon fuel such as methane can be more stably manufactured at low cost. Further, by stably supplying the surplus power, the operation rate of the water electrolysis devices 2B and 2C utilizing the surplus power can be improved, and the economics of “power-to-gas” can be improved.

  Further, according to the present embodiment, the renewable energy power generation devices 1B and 1C are the photovoltaic power generation devices 1Ba and 1Ca, and the water electrolysis devices 2B and 2C have the surplus power during the daytime from the photovoltaic power generation devices 1Ba and 1Ca. And the nighttime surplus power is supplied from the biomass power generation devices 5B and 5C or the garbage power generation device 5C, so that the surplus power can be stably supplied to the water electrolysis devices 2B and 2C day and night. Therefore, surplus electric power can be supplied to the water electrolyzers 2B and 2C more stably and at low cost, and more stable and inexpensive hydrocarbon fuel such as methane can be produced.

  Further, according to the present embodiment, the biomass power generators 5B, 5C or the garbage power generator 5C are arranged in the same premises as the water electrolysis devices 2B, 2C, so that when supplying surplus power to the water electrolysis devices 2B, 2C. There is no need to go through an off-premise power system. Therefore, surplus power can be supplied to the water electrolysis devices 2B and 2C more easily and at lower cost, and a more stable and inexpensive hydrocarbon fuel such as methane can be produced.

  According to the present embodiment, a part of hydrocarbon fuel such as methane produced by the methanation facilities 3B and 3C is supplied to the biomass power generators 5B and 5C or the garbage power generator 5C as a fuel for auxiliary combustion. By utilizing hydrocarbon fuel such as methane and CO2 free in the system, the carbon dioxide emission coefficient at the time of power generation in the biomass power generators 5B and 5C or the garbage power generator 5C is further reduced, and the regeneration with less environmental load is achieved. Possible energy utilization systems 10B and 10C can be realized.

<Modification>
The embodiment described above can be modified without changing the gist of the present invention. For example, according to the present embodiment, the renewable energy power generation devices 1B and 1C are the solar power generation devices 1Ba and 1Ca, and the water electrolysis devices 2B and 2C have the surplus power during the daytime from the solar power generation devices 1Ba and 1Ca. , And nighttime surplus power is supplied from the biomass power generators 5B and 5C or the garbage power generator 5C, but it is not necessarily limited to this. For example, a renewable energy power generation device is a renewable energy power generation device other than a biomass power generation device, and a water electrolysis device is supplied with surplus power in the daytime from a renewable energy power generation device other than a biomass power generation device. The surplus power at night may be supplied from 5B and 5C. This is because the generation time of surplus power may differ depending on the type of the renewable energy power generation device, and it is only necessary to be able to utilize this effectively.

  Further, according to the present embodiment, the biomass power generators 5B, 5C or the refuse power generator 5C are arranged in the same premises as the water electrolysis devices 2B, 2C, but the renewable energy power generators 1B, 1C and the biomass power generator 5B, 5C or the waste power generation device 5C may be arranged in the same premises as the water electrolysis devices 2B and 2C. When supplying surplus electric power from the renewable energy power generators 1B and 1C to the water electrolyzers 2B and 2C, the surplus electric power does not need to pass through an off-site electric power system, and the surplus electric power can be supplied more easily and at low cost. Because it can be supplied to

  The present invention provides, for example, a method of synthesizing hydrogen produced using surplus power of a renewable energy power generation device and carbon dioxide generated during biogas generation or biomass power generation to produce a hydrocarbon fuel such as methane. It can be used as a possible energy utilization system.

1, 1B, 1C Renewable energy power generator 1Ba, 1Ca Solar power generator 2, 2B, 2C Water electrolysis equipment 3, 3B, 3C Methanation equipment 4, 4B Biogasification equipment 5B, 5C Biomass power generator 5C Garbage power generator 6B, 6C Carbon dioxide separation and recovery device 7B, 7C Hydrogen storage alloy 8B, 8C Surplus power monitoring device 10, 10B, 10C Renewable energy utilization system 41, 41B Activated sludge tank 42, 42B Fermentation tank tank 43, 43B Carbon dioxide separation apparatus

Claims (7)

A water electrolysis device that produces hydrogen and oxygen using surplus power of a renewable energy power generation device, and a hydrocarbon such as methane obtained by synthesizing hydrogen produced by the water electrolysis device and carbon dioxide generated in the system. A renewable energy utilization system comprising a methanation facility for producing fuel,
The system includes a biogasification facility having an activated sludge tank, a fermentation tank tank, and a carbon dioxide separation device,
The water electrolyzer uses the surplus power to produce oxygen together with hydrogen, supplying the activated sludge tank,
Renewable by synthesizing carbon dioxide separated by the carbon dioxide separation device and hydrogen obtained by the water electrolysis device in the methanation facility to produce a hydrocarbon fuel such as methane. Energy utilization system. In the renewable energy utilization system according to claim 1,
The system includes a biomass power generation device that generates power by burning biofuel discharged from the biogasification facility, and a carbon dioxide separation and recovery device that separates and recovers carbon dioxide from exhaust gas of the biomass power generation device,
Regeneration characterized in that carbon dioxide separated and recovered by the carbon dioxide separation and recovery apparatus and hydrogen obtained by the water electrolysis apparatus are synthesized by the methanation facility to produce a hydrocarbon fuel such as methane. Possible energy utilization system. A water electrolysis device that produces hydrogen and oxygen using surplus power of a renewable energy power generation device, and a hydrocarbon such as methane obtained by synthesizing hydrogen produced by the water electrolysis device and carbon dioxide generated in the system. A renewable energy utilization system comprising a methanation facility for producing fuel,
The system includes a biomass power generation device or a refuse power generation device, and a carbon dioxide separation / recovery device for separating and recovering carbon dioxide from exhaust gas of the biomass power generation device or the refuse power generation device,
The water electrolysis device produces oxygen together with hydrogen using the surplus power, supplying the biomass power generation device or a combustor of the garbage power generation device,
It is characterized in that carbon dioxide separated and recovered by the carbon dioxide separation and recovery apparatus and hydrogen obtained by the water electrolysis apparatus are synthesized by the methanation facility to produce a hydrocarbon fuel such as methane. Renewable energy utilization system. In the renewable energy utilization system according to claim 2 or 3,
A renewable energy utilization system, wherein surplus power is selectively supplied to the water electrolysis device from the renewable energy power generation device, the biomass power generation device, or the waste power generation device. In the renewable energy utilization system according to claim 4,
The renewable energy power generation device is a photovoltaic power generation device, the water electrolysis device supplies surplus power during the day from the photovoltaic power generation device, and the surplus power during the night from the biomass power generation device or the garbage power generation device. Renewable energy utilization system characterized by supplying. In the renewable energy utilization system according to claim 4 or 5,
The biomass power generation device or the refuse power generation device is disposed in the same premises as the water electrolysis device, wherein a renewable energy utilization system is provided. In the renewable energy utilization system according to any one of claims 2 to 6,
A renewable energy utilization system, wherein a part of a hydrocarbon fuel such as methane produced in the methanation facility is supplied to the biomass power generation device or the refuse power generation device as an auxiliary fuel.

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