JP5737567B2 - Renewable energy multistage utilization system - Google Patents

Description

The present invention improves the power generation efficiency of the photovoltaic power generation apparatus, and anaerobically ferment microalgae to generate methane, and simultaneously supply the generated carbon dioxide to the microalgae, thereby using renewable energy in multiple stages. About the system.
Specifically, the light-receiving surface of a photovoltaic power generation device installed on the surface of an artificial pond is cooled to improve power generation efficiency, and microalgae are cultured around the solar power generation device, thereby enabling multistage use of land. In addition, methane produced by fermenting cultured microalgae is used as a fuel, and at the same time, carbon dioxide produced is supplied to the microalgae to promote biomass cultivation and fix carbon dioxide. The present invention relates to a multistage utilization system of possible energy.

  It is known that carbon dioxide discharged into the atmosphere from power plants, factories, automobiles, etc. due to human social activities is the main cause of global warming. Reduction is a major issue in protecting the global environment. In view of this background, power generation using natural energy such as solar power generation, wind power generation, geothermal power generation, mini hydroelectric power generation or wave power generation, and biomass are used as methods for obtaining energy without increasing carbon dioxide emissions. Technology development related to renewable energy, such as power generation and fuel production such as methane and methanol, is underway.

  In solar power generation, it is known that the temperature greatly affects the power generation efficiency, and the amount of power generation decreases as the temperature of the solar cell increases. For example, in the case of a silicon-based solar cell, when the temperature reaches 80 ° C., the photoelectric conversion efficiency may decrease by 20% or more compared to the rated state of 25 ° C. Moreover, when the temperature of a solar cell rises rapidly, the heat load will be applied to the structural member of a solar power generation device, and the problem that a solar cell deteriorates may arise. Therefore, it has been proposed to cool the solar power generation apparatus by an air cooling method or a water cooling method (for example, see Patent Documents 1 to 3).

  On the other hand, a method of generating methane and carbon dioxide by anaerobic fermentation of algae and supplying the carbon dioxide to algae has also been proposed (see Patent Documents 4 and 5). However, the biomass obtained by cultivation has a very large procurement amount and has the advantage of being cheap compared to solar and wind power, but the energy obtained per unit land (cultivation) area is more than that of other RPS power sources. There is a problem that it is remarkably low, and the energy density is about 1/50 to 1/100 that of sunlight.

  By the way, as a method of obtaining renewable energy by combining power generation using natural energy and biomass, for example, Patent Document 6 discloses fermenting biomass using electric power obtained by solar power generation or wind power generation. A method for producing methane gas is disclosed, and Patent Document 7 discloses the production of hydrogen by electrolyzing water using electric power obtained by solar power generation or wind power generation. A method is disclosed in which methanol is obtained by reacting with the product gas generated by the conversion.

  The method disclosed in Patent Document 6 or Patent Document 7 combines natural energy such as sunlight and wind power with biomass that is renewable energy. The place to obtain is not limited to the same place, nor is it intended to increase the total amount of renewable energy obtained from the unit area.

JP 2002-170974 A (Claim 1) JP 2004-259797 A (paragraphs [0003] to [0005]) JP 2004-259797 A (Claims 1 to 6) JP 2010-088368 A (Claims 6 and 7) Japanese Patent No. 3004510 (paragraph [0010]) JP 2007-313427 A JP 2002-193858 A

  The present invention is to install a solar power generation device in a specific place for storing water, in which microalgae are cultured, increase the power generation efficiency of the solar power generation device, and the microalgae can be fermented and used as fuel. Another object of the present invention is to provide a renewable energy multistage utilization system that can increase the total amount of renewable energy obtained from a unit area without increasing the amount of carbon dioxide emitted during fermentation.

In order to achieve the above object, the present invention provides a system having the following configuration.
(1) A solar power generation device is installed in an artificial pond for storing water, microalgae are cultured in the artificial pond, the microalgae are fermented to produce methane and carbon dioxide, and the carbon dioxide is A renewable energy multistage utilization system immobilized on microalgae,
A watering device for spraying water on the light receiving surface of the solar power generation device;
A solid-liquid separation device for separating microalgae cultured in an artificial pond;
A methane fermenter for fermenting the separated microalgae at 37 to 55 ° C . ;
As a heating heat source for the methane fermentation tank, a circulation system that circulates water from the sprinkler (warm water) or artificial pond water that has passed through a heat exchanger to the methane fermentation tank,
A methane gas refining device that separates methane gas discharged from the methane fermentation tank from carbon dioxide,
Transfer means for supplying the artificial pond with carbon dioxide separated by a methane gas purification device;
A renewable energy multistage utilization system characterized by comprising:
(2) In the above (1), the watering device is provided with a control device capable of turning on and off the watering device in conjunction with the temperature detected by a temperature sensor installed on the light receiving surface of the photovoltaic power generation device. The renewable energy multistage utilization system described.
(3) When the temperature detected by the temperature sensor exceeds the first predetermined temperature, the control device starts spraying water on the light receiving surface, and the temperature detected by the temperature sensor becomes equal to or lower than the second predetermined temperature. The renewable energy multistage use system according to (2) above, wherein the spraying of water is stopped in the event of a failure.
(4) The renewable energy multistage use system according to (2) or (3) above, wherein the power generated by the photovoltaic power generation device is used as a power source for the watering device and a power source for the control device.
(5) The above (2) to (2), wherein a storage battery for storing the generated power of the solar power generation device is installed, and the stored power is supplied to a power source of the watering device and a power source of the control device. 4) The renewable energy multistage utilization system according to any one of 4).
(6) In the above (5), characterized in that a stirring device capable of stirring the water in the artificial pond is provided, and the power generated by the solar power generation device or the discharge power from the storage battery is used as a power source of the stirring device. The renewable energy multistage utilization system described.

  According to the multistage utilization system of renewable energy of the present invention, a photovoltaic power generation device is installed by installing a photovoltaic power generation device in an artificial pond that stores water and spraying water on a light receiving surface of the photovoltaic power generation device. As well as preventing reduction in conversion efficiency and cultivating microalgae in artificial ponds, renewable energy can be obtained from solar power generation devices as power and from microalgae as biomass fuel, respectively. It becomes possible to increase the total amount of renewable energy obtained from the unit area. Since the solar power generation device is installed in the pond, compared to the installation on the ground, the radiant heat due to the reflection of sunlight is suppressed, and the temperature rise of the light receiving surface is suppressed.

  In addition, methane obtained by fermentation of microalgae can be used as a fuel, and by simultaneously supplying carbon dioxide generated to microalgae, immobilization and cultivation promotion can be performed simultaneously. Since the generated carbon dioxide is supplied to microalgae, the amount of carbon dioxide generated does not increase.

  Furthermore, it can utilize as a heating heat source of a methane fermentation tank by controlling the temperature of sprinkling drainage or the stored water to the temperature range suitable for cultivation of a micro algae and fermentation of a methane fermentation tank.

It is the schematic which shows the multistage utilization system of the renewable energy which concerns on this invention. It is the schematic which shows cultivation of a solar power generation device and micro algae. It is the schematic which shows the connection of each apparatus of a solar power generation device periphery. It is a graph which shows the methane generation amount at the time of processing a chlorella using a methane fermentation microbe.

  Hereinafter, a preferred embodiment of a renewable energy multistage utilization system according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing a preferable example of a renewable energy multistage utilization system, FIG. 2 is a schematic diagram showing cultivation of a solar power generation device and microalgae in the system, and FIG. It is the schematic which shows the connection of an apparatus. 1 to 3, the same numbers are assigned to the same devices.

  As shown in FIG. 1, the renewable energy multistage utilization system of the present invention sprays water for cooling a solar power generation device 2 and a light receiving surface of the solar power generation device 2 into an artificial pond 1 for storing water. The watering device 3 is installed, and water is supplied from the outside of the artificial pond 1 to the watering device 3 through the pump 4 and the water supply pipe 5. The pump 4 and the water supply pipe 5 constitute a water supply device. A water supply pipe 5 is connected to the watering device 3. In the artificial pond 1, an agitator 6 for agitating the water of the artificial pond 1 and sufficiently supplying carbon dioxide necessary for photosynthesis to the water is installed. Microalgae 7 is cultured. 8 is a nutrient supply pipe for supplying nutrients necessary for the microalgae 7, and is installed as necessary. Although not shown in FIG. 1, a storage battery 9 for storing the power generated by the solar power generation device 2 and a control device 12 for controlling the drive of the pump 4 are attached around the artificial pond 1. The temperature sensor 11 is attached to the light receiving surface of the photovoltaic power generator 2.

  The solar power generation device 2 is placed above the water surface by a gantry 2 a installed in the artificial pond 1. The shape of the gantry 2a is arbitrary, and it is preferable that the gantry is an inclined gantry with an appropriate inclination so that the light-receiving surface of the solar power generation device 2 is effectively exposed to sunlight. The number of installed solar power generation devices 2 is not particularly limited, and may be determined according to the size of the artificial pond 1, or conversely, the required number of solar power generation devices 2 is obtained from the target power generation amount. The size of the artificial pond may be determined accordingly. The shape of the pond is determined as appropriate according to the size, but considering the efficiency of stirring, a circular shape or an elliptical shape (raceway) is preferable.

  The watering device 3 is not particularly limited. As shown in FIG. 1, a tube having a plurality of holes at predetermined intervals is fixed to the upper part of the light receiving surface of each solar power generation device 2. It is also possible to use a watering device of a type in which water is poured out on the light receiving surface. Alternatively, as shown in FIG. 2, water is sprayed on the light-receiving surfaces of a plurality of surrounding solar power generation devices 2 while rotating a tube having a plurality of holes in a horizontal direction with a power source such as a motor. A watering device may be used.

  When sunlight is irradiated, the temperature of the light receiving surface of the photovoltaic power generator 2 rises, and water evaporates from the artificial pond 1 to lower the pond water level. Since the temperature sensor 11 is installed on the light receiving surface of the solar power generation device 2, when the temperature of the light receiving surface detected by the temperature sensor 11 exceeds a preset temperature, the control device 12 is activated and the pump is activated. 4 is driven and water is sprinkled from the water sprinkler 3 on the light receiving surface.

  Examples of water include river water, industrial water, groundwater, and tap water. Water can be used as cooling water for the light receiving surface by supplying water by a method of spraying from the water sprinkler 3 to the light receiving surface of the solar power generation device 2 through the water supply pipe 5 using the pump 4, and the water level is Since fresh water can be replenished to the lowered artificial pond 1, it is possible to prevent the nutrient added for culturing the microalgae 7 from being concentrated by evaporation of water. In addition, when a newly supplied water source is difficult to supply due to drought or the like, the water of the artificial pond 1 can be used as the water sprayed from the sprinkler 3, and in this case, the artificial pond 1 using the pump 4. The water is pumped up and sprayed to cool the light receiving surface of the solar power generation device 2. The pump 4 that pumps up the water in the artificial pond 1 may be appropriately fitted with a filtration device to prevent inhalation of the cultured microalgae 7.

  When it is necessary to add nutrients necessary for culturing the microalgae 7, the nutrients can be added to the required pond surface. In this case, it is also possible to drop and supply to the pond according to the amount of water sprayed from the nutrient supply pipe 8 installed in the lower part of the solar panel separately from the water spray device 3. The nutrient supply pipe 8 may be a pipe of a system in which nutrient-containing water is sprayed from a pipe having a plurality of holes at predetermined intervals toward the water surface, and prevents salt from depositing on the light receiving surface of the solar panel. Therefore, it is installed at the bottom of the solar panel.

  When cultivating marine microalgae, salt or concentrated salt water can be added directly to the pond surface from a salt addition pipe installed at the bottom of the solar panel provided separately from the sprinkler pipe according to the amount of sprinkler. .

  As the above nutrients, nitrogen, phosphoric acid, potassium and trace minerals are mainly added. For example, potassium nitrate, dipotassium hydrogen phosphate, magnesium sulfate, calcium chloride, ferric citrate, cobalt chloride, boric acid, Manganese chloride, zinc sulfate, copper sulfate, sodium molybdenum and the like can be mentioned.

  The stirring device 6 stirs water in which the microalgae 7 are cultured. Thereby, it is possible to prevent the microalgae 7 from staying in the shaded portion by the solar power generation device 2 and to prevent the microalgae 7 from sinking to the bottom of the artificial pond 1, so that the culture is efficiently performed. be able to. The shape of the stirring device 6 is not particularly limited, and examples thereof include a rotary blade type stirrer. The stirrer 6 can effectively lower the water temperature of the artificial pond 1 that has risen during the daytime by operating even at night when the temperature decreases.

  As the microalgae 7 used in the present invention, Spirulina, Donariella, Chlorella, Senedesmus, Botryococcus, Synecococcus, Synecocystis, Chlamydomonas, Desmodemusmus, Nannochloropsis, Nannochloris, Tetracellmis, Euglena, Pseudocollistis, Clostellium, Microcystis , Anxtrodesmus, Gorenkinia, Serenastrum, Protochiffon, Volbox, Chlorococum, Hematococcus, Anabena, Microkistis, Formidium and the like. Nutrients necessary for the growth of the microalgae 7 can be added to the water of the artificial pond 1 in advance. After culturing for a predetermined period, the microalgae 7 is extracted together with water by a pump or the like, separated using a solid-liquid separator 16 such as a belt press, and then introduced into the methane fermentation tank 17. Further, pigments, physiologically active substances such as DHA, EPA, astaxanthin, and glutamic acid may be extracted from the microalgae 7 and the remaining microalgae residue may be introduced into the methane fermentation tank 17.

  The microalgae 7 separated by the solid-liquid separator 16 is introduced into the methane fermentation tank 17. In the methane fermentation tank 17, a conventionally known production method can be arbitrarily applied. The microalgae 7 may be introduced directly into the methane fermentation tank 17, or, if necessary, for example, a mixing tank is provided in the upstream of the methane fermentation tank 17, and water is added to the microalgae 7 in the mixing tank. A method in which a product diluted to a concentration of about 80% to 90% moisture is introduced into the methane fermentation tank 17 and subjected to methane fermentation at a fermentation temperature of 37 to 55 ° C. Moreover, when employ | adopting a dry-type fermentation method, the method of adding paper waste etc. with little water content suitably, and carrying out methane fermentation at the fermentation temperature of 37-55 degreeC is mentioned.

  In the methane fermenter 17, a gas mainly containing methane gas and carbon dioxide is generated by the decomposition reaction of the microalgae 7 by known methane-producing bacteria. In the methane fermentation tank 17, the water of the artificial pond 1 is used as a heating heat source. Therefore, the renewable energy multistage utilization system of the present invention has a circulation system 18 for circulating the water of the artificial pond 1 to the methane fermentation tank 17. When the water in the artificial pond 1 is circulated, water is drawn from the artificial pond 1 and the water temperature is controlled to a temperature suitable for fermentation in the methane fermentation tank 17 through a heat exchanger (not shown) arranged in the circulation system 18. To do. Moreover, when the water temperature of the artificial pond 1 is low, the waste water (warm water) flowing out from the sprinkler 3 may be directly led to the circulation system 18.

  The methane gas discharged from the methane fermentation tank 17 is separated from carbon dioxide in the methane gas purification device 19. As the methane gas purification device 19, for example, a compressor that pressurizes the exhaust gas from the methane fermentation tank 17 to 0.55 to 2.0 MPa, and the pressurized exhaust gas and water are brought into contact with each other to dissolve carbon dioxide in the water. And a decompression tank for returning water in which carbon dioxide is dissolved in the absorption tower to an atmospheric pressure state. By setting the inside of the absorption tower to a pressurized condition, carbon dioxide having a saturation concentration or higher under atmospheric pressure is dissolved in water, carbon dioxide from the exhaust gas is removed, and high-purity methane gas is discharged from the absorption tower. In addition, the methane gas purifier is configured to discharge the saturated carbonated water after discharging the supersaturated portion of carbon dioxide dissolved in supersaturation by depressurizing the waste water from the absorption tower to atmospheric pressure with a decompression tank. 19 can be used.

  Since the gas discharged from the absorption tower is methane gas purified to a high purity, it can be passed through a dehumidifier or the like and dried, then stored in a gas tank (methane holder) 20 and used as fuel.

  Since the carbon dioxide that has been dissolved excessively is released by returning to the atmospheric pressure state in the decompression tank, the carbon dioxide dissolved in the carbon dioxide gas and water (carbonated water) is artificially transferred via the transfer means 21. Supplied to pond 1 The cultivation of the microalgae 7 cultured in the artificial pond 1 is promoted by supplying carbon dioxide. Since carbon dioxide generated in the methane fermentation tank 17 is immobilized on the microalgae 7, the amount of carbon dioxide does not increase.

  Next, with reference to FIG. 3, the connection of each apparatus in the renewable energy multistage utilization system of this invention is demonstrated.

  The photovoltaic power generation apparatus 2 is connected to the system power supply 14 via the bidirectional converter 10, and the pump 4 is connected to the connection point between the output side of the bidirectional converter 10 and the system power supply 14 via the switch 13. ing. Opening and closing of the switch 13 is controlled by the control device 12. A stirring device 6 is connected in parallel with the switch 13.

  A storage battery 9 is connected to the input side of the bidirectional converter 10. When installing a plurality of photovoltaic power generation devices 2, storage batteries 9 may be installed corresponding to each photovoltaic power generation device 2, but the plurality of photovoltaic power generation devices 2 are arranged in parallel with one common storage battery 9. It is preferable to connect to the system because the system can be made compact.

  A temperature sensor 11 is installed on the light receiving surface of the solar power generation device 2, and the temperature sensor 11 has a connection circuit between the temperature sensor 11 and the temperature of the light receiving surface detected by the temperature sensor 11 is set in advance. When the temperature exceeds the first predetermined temperature, the control device 12 turns on the switch 13 to drive the pump 4 to spray water from the water sprinkler 3 onto the light receiving surface. When the light receiving surface is cooled and the temperature of the light receiving surface detected by the temperature sensor 11 falls below a second predetermined temperature set in advance, the control device 12 turns off the switch 13 and stops driving the pump 4. The first predetermined temperature is usually set within a range of about 40 to 75 ° C. The second predetermined temperature is set lower than the first predetermined temperature, and is usually set within a range of about 20 to 35 ° C.

  The electric power generated by the solar power generation device 2 is charged to the storage battery 9 and used as a power source for the pump 4 and the stirring device 6 and a power source for the control device 12. Further, since the discharge power of the storage battery 9 is also used as the power source of the pump 4 and the agitating device 6 and the power source of the control device 12, the solar power generation device 2 is in the power generation state and the storage battery 9 is in the discharge state. In addition, the power surplus than that required to drive the stirring device 6 is reversely flowed to the system power supply 14.

  The light receiving surface of the solar power generation device 2 is irradiated with sunlight, and power is generated and the temperature rises. The temperature sensor 11 installed on the light receiving surface detects the temperature, and the first predetermined temperature is set. Since the control device 12 is activated and the switch 13 is turned on at the time of exceeding, the pump 4 is driven and water is scattered from the water spray device 3 to the light receiving surface, so that the photoelectric conversion efficiency of the solar power generation device 2 is lowered. Can be prevented. Since the switch 13 is turned off by the control device 12 and the pump 4 is stopped when the light receiving surface is cooled down to the second predetermined temperature or lower, it is efficiently performed without using wasted power. The light receiving surface can be cooled.

  In addition, since the solar power generation device 2 and the storage battery 9 are connected to the system power supply 14 via the bidirectional converter 10, the output of the solar power generation device 2 is insufficient to charge the storage battery 9 depending on weather conditions. In this case, the accumulator 9 is charged by converting the alternating current of the system power supply 14 into direct current. Between the solar power generation device 2 and the bidirectional converter 10, a backflow prevention diode 15 is disposed. Further, in the case where the stirring device 6 is operated at night when there is no power generation by the solar power generation device 2, when the storage amount of the storage battery 9 is close to the discharge lower limit value and cannot be operated by the discharge from the storage battery 9, Operated by electric power.

  As described above, according to the present invention, it is possible to improve the power generation efficiency by cooling the light receiving surface of the solar power generation device using a part of the generated power of the solar power generation device, and at the same time culturing microalgae. Since the methane produced by methane fermentation can be used as biomass fuel, the total amount of renewable energy obtained from the unit area can be increased. Moreover, since the water (hot water) of an artificial pond can be collect | recovered and utilized as a heating heat source of a methane fermentation tank, it is energy saving. Carbon dioxide generated in the methane fermenter can be returned to the artificial pond and used for culturing microalgae, so that carbon dioxide generation can be reduced to zero.

  Hereinafter, although an example of methane fermentation will be specifically described with test examples, the present invention is not limited to the following examples.

(Test example)
Prepare a 250 ml screw cap and a plastic cap (BOLA G-L45 (Finemech, Germany)) with a plastic penetrating into the bottle, and put 10 g of dried chlorella and 100 ml of water in the bottle. After adding the methane fermentation bacteria group separated from the soil, it was covered with a cap. The end of the plastic tube attached to the cap is introduced into an aluminum bag for gas collection (manufactured by GL Sciences Inc.), and a screw bottle is immersed in a constant temperature water bath (manufactured by Taitec Co., Ltd., SJ-07N). Static culture was performed at 0 ° C. On the 8th, 15th, 21st, 28th and 36th days after the start of the culture, the aluminum bag was replaced, and the removed aluminum bag was filled with gas in the bag with a 100 ml glass syringe. While extracting and measuring the gas volume, the concentration of methane in the extracted gas is measured by gas chromatography (manufactured by Shimadzu Corporation, GC2010, detector FID, column ZB-1) to determine the cumulative amount of methane produced. It was. The results are shown in Fig.4.

  As shown in FIG. 4, it is understood that about 400 mg of methane is produced from 10 g of chlorella in 36 days.

  According to the renewable energy multistage utilization system of the present invention, the cultivation of microalgae and photovoltaic power generation can be performed simultaneously in the same place, and the power generation efficiency can be improved by cooling the light receiving surface of the photovoltaic power generation device. It is extremely useful as a system for increasing the total amount of renewable energy obtained from a unit area.

DESCRIPTION OF SYMBOLS 1 Artificial pond 2 Solar power generation device 2a Mounting frame 3 Water sprinkling device 4 Pump 5 Water supply piping 6 Stirring device 7 Microalgae 8 Nutrient supply piping 9 Storage battery 10 Bidirectional converter 11 Temperature sensor 12 Control device 13 Switch 14 System power supply 15 Backflow prevention diode 16 Solid-liquid separator 17 Methane fermentation tank 18 Circulation system 19 Methane gas purification device 20 Gas tank (methane holder)
21 Transfer means

Claims (6)

A solar power generation device is installed in an artificial pond that stores water, microalgae are cultured in the artificial pond, the microalgae are fermented to produce methane and carbon dioxide, and the carbon dioxide is converted into the microalgae. A fixed renewable energy multi-stage system,
A watering device for spraying water on the light receiving surface of the solar power generation device;
A solid-liquid separation device for separating microalgae cultured in an artificial pond;
A methane fermenter for fermenting the separated microalgae at 37 to 55 ° C . ;
As a heating heat source for the methane fermentation tank, a circulation system that circulates water from the sprinkler (warm water) or artificial pond water that has passed through a heat exchanger to the methane fermentation tank,
A methane gas refining device that separates methane gas discharged from the methane fermentation tank from carbon dioxide,
Transfer means for supplying the artificial pond with carbon dioxide separated by a methane gas purification device;
A renewable energy multistage utilization system characterized by comprising:
  The regenerator according to claim 1, wherein the watering device is provided with a control device capable of turning on and off the watering device in conjunction with a temperature detected by a temperature sensor installed on a light receiving surface of the photovoltaic power generation device. Energy multistage use system.   When the temperature detected by the temperature sensor exceeds a first predetermined temperature, the control device starts spraying water on the light receiving surface, and when the temperature detected by the temperature sensor falls below a second predetermined temperature. 3. The renewable energy multi-stage utilization system according to claim 2, wherein the spraying of water is stopped.   4. The renewable energy multistage utilization system according to claim 2, wherein generated power of a solar power generation device is used as a power source of the watering device and a power source of the control device. 5.   The storage battery which stores the generated electric power of the said solar power generation device is installed, and the stored electric power is supplied to the power source of the watering device and the power source of the control device. The renewable energy multistage utilization system described. The regenerator according to claim 5, further comprising a stirring device capable of stirring the water in the artificial pond, wherein the power generated by the solar power generation device or the discharge power generated by the storage battery is used as a power source of the stirring device. Energy multistage use system.