Energy generation system

Abstract

This system contributes to carbon neutrality and provides an energy generation system that efficiently creates novel energy materials for power generation that do not require sunlight. [Solution] The energy generation system comprises an organic matter generation device 1 that produces organic matter from chemosynthetic bacteria, carbon dioxide, and hydrogen sulfide, and a methane fermentation device 2 that ferments the organic matter recovered from the organic matter generation device 1.

Description

Technical Field

[0001] The present invention relates to an energy creation system for creating energy materials used in power generation and the like.

Background Art

[0002] In recent years, carbon neutrality, which aims to make the overall emissions of greenhouse gases zero, has been declared, and in order to achieve this, the creation of new energy, particularly energy for power generation, is desired. Photovoltaic power generation, which does not emit carbon dioxide, can contribute to carbon neutrality, but has a problem that its output fluctuates depending on natural conditions such as the weather.

[0003] As an energy material for power generation that does not require sunlight, biogas (methane gas) generated from organic waste is known. In the biogas generation system disclosed in Patent Document 1, organic acids are generated from organic substances obtained by decomposing organic waste with facultative anaerobic bacteria, and methane gas is generated by fermenting the generated organic acids with methane-producing bacteria. The generated methane gas is supplied to a cogeneration engine and used as an energy material for power generation.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The biogas generation system according to Patent Document 1 has an advantage of generating methane gas without requiring sunlight, but since it uses organic waste as a raw material, there is a problem that it costs for collection and transportation of organic waste, and further for removal of unnecessary substances mixed in the organic waste.

[0006] Therefore, the objective of the present invention is to provide an energy generation system that contributes to carbon neutrality and efficiently generates novel energy materials for power generation that do not require sunlight. [Means for solving the problem]

[0007] The energy generation system according to the present invention comprises an organic matter generation device that produces organic matter from chemosynthetic bacteria, carbon dioxide, and hydrogen sulfide, and a methane fermentation device that ferments the organic matter recovered from the organic matter generation device.

[0008] In this configuration, chemosynthetic bacteria (e.g., sulfur-oxidizing bacteria, nitrifying bacteria, etc.) housed in the organic matter generation device produce organic matter (e.g., glucose) through a chemical reaction using carbon dioxide and hydrogen sulfide that does not require sunlight. The produced organic matter is then subjected to methane fermentation in a methane fermentation device, generating methane and carbon dioxide. The generated methane can be used as an energy source for power generation, and the carbon dioxide can be returned to the organic matter generation device and used for organic matter generation. Furthermore, since hydrogen sulfide, a hazardous substance, is used, it is also effective as a hazardous waste treatment method.

[0009] In this invention, it is proposed that the organic matter production device produces the organic matter using the gill cells of the clam *Clavaria*, which harbors the chemosynthetic bacteria. Chemosynthetic bacteria that synthesize organic matter using hydrogen sulfide live symbiotically within the gill cells of *Clavaria*, and since they inhabit cold seeps and hydrothermal vents around the Japanese archipelago, they can be suitably used as chemosynthetic bacteria in this invention.

[0010] Since the white clam (Latrodectus fuscescens) inhabits cold seeps and hydrothermal vents in the deep sea, placing an organic matter generating device in such deep-sea areas easily creates a favorable environment for the clam, which is advantageous. For this reason, the present invention proposes that the organic matter generating device be placed in the deep sea, which is the habitat of the white clam.

[0011] When using gill cells of the clam *Clavaria* as chemosynthetic bacteria, it is advantageous to have a filtration space through which hydrogen sulfide flows between the membranes to which the gill cells are attached (cultured) in order to effectively produce organic matter by the chemosynthetic bacteria symbiotic with the gill cells. Such a configuration can be implemented using an immersion-type membrane separation device. Therefore, in this invention, it is proposed that the organic matter production device has an immersion-type membrane separation device, and the gill cells are attached to the immersion-type membrane separation device.

[0012] When an immersion-type membrane separator is used in an organic matter generation apparatus, it is preferable to supply a sufficient amount of hydrogen sulfide and to immerse the immersion-type membrane separator in water containing a sufficient amount of carbon dioxide in order to effectively calculate organic matter. For this reason, the present invention proposes that a hydrogen sulfide supply unit is provided to supply hydrogen sulfide to the immersion-type membrane separator, and that the immersion-type membrane separator is immersed in water. The water in this case may include tap water, rainwater, carbonated water with dissolved carbon dioxide, seawater, etc.

[0013] When an immersion membrane separator is installed in the sea, preferably in the deep sea, the immersion membrane separator needs to be brought to the surface for periodic maintenance, and is firmly fixed to a fixing frame or the like. Also, when the organic matter generation device is installed on land, a container for holding water around the immersion membrane separator is essential. A tank for housing the immersion membrane separator is suitable as such a fixing frame or container. For this reason, the present invention proposes that the immersion membrane separator be installed in a water-filled generation tank.

[0014] Since methane generated in a methane fermentation apparatus readily triggers exothermic reactions, it is preferable to use the generated methane as an energy source as quickly as possible and over the shortest possible transport distance. For this reason, the present invention proposes that the apparatus be equipped with a power generation device that generates electricity using the methane generated in the aforementioned methane fermentation apparatus.

[0015] In the chemical reaction for organic matter production carried out in the organic matter generation apparatus, oxygen, water, and sulfur are produced in addition to organic matter. This oxygen can be effectively utilized in a power generation apparatus that performs methane power generation. For this reason, the present invention proposes that the oxygen generated in the organic matter generation apparatus be supplied to the power generation apparatus.

[0016] In a methane fermentation apparatus, methane and carbon dioxide are produced when organic matter such as glucose is fermented. Similarly, in a power generation apparatus that uses methane, water and carbon dioxide are produced along with thermal energy. At least a portion of the carbon dioxide thus produced is returned to an organic matter production apparatus that requires carbon dioxide for organic matter production, thereby enabling the energy creation system of the present invention to contribute to carbon neutrality. For this reason, the present invention proposes that at least a portion of the carbon dioxide produced in the methane fermentation apparatus and the power generation apparatus be dissolved in a carbon dioxide dissolution tank that is circulated and connected to the production tank of the organic matter production apparatus. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic diagram showing the general configuration of an energy generation system. [Figure 2] This is a schematic diagram illustrating organic matter production in an immersion-type membrane separation apparatus equipped with gill cells from the white clam (Latrodectus fuscescens). [Figure 3] This is a schematic diagram illustrating an embodiment in which organic matter is supplied from an organic matter generation device using gill cells of the clam *Clavaria* to a methane fermentation device via detached gill cells. [Figure 4] This is a conceptual diagram of an energy generation system using a deep-sea power generation unit. [Modes for carrying out the invention]

[0018] Figure 1 schematically shows the general configuration of the energy generation system according to the present invention. This energy generation system comprises an organic matter generation device 1 and a methane fermentation device 2.

[0019] The organic matter generation device 1 produces organic matter from chemosynthetic bacteria, carbon dioxide, and hydrogen sulfide. Chemosynthetic bacteria do not require sunlight and oxidize one of various substances (such as hydrogen, ammonia, nitrite, reducing sulfur compounds, iron, etc.) existing in the earth environment with an enzyme held by the chemosynthetic bacteria themselves. During this oxidation, the energy generated reduces NAD(P): nicotinamide adenine dinucleotide phosphate and obtains ATP: adenosine triphosphate. Further, using these, it operates a carbon dioxide fixation system such as the Calvin-Benson cycle to synthesize organic carbon compounds. Examples of chemosynthetic bacteria include sulfur-oxidizing bacteria, nitrifying bacteria, iron bacteria, and hydrogen bacteria. In this embodiment, sulfur-oxidizing bacteria are used as the chemosynthetic bacteria.

[0020] The chemical reaction formula of the artificial chemical synthesis performed by such an organic matter generation device 1 is, as shown in (1) of FIG. 1,

Chem.

[0021] The methane fermentation device 2 ferments the organic matter recovered from the organic matter generation device 1. Methane is generated by this methane fermentation. The chemical reaction formula of the methane fermentation performed by the methane fermentation device 2 is, as shown in (2) of FIG. 1,

Chem.

[0022] The organic matter generation apparatus 1 is equipped with a generation tank 1A that generates organic matter through the chemical reaction shown in "Chemical Formula 1" above. Furthermore, it is advantageous to provide a carbon dioxide dissolution tank 4 that is circulated and connected to the generation tank 1A by a circulation channel 52. Water with a decreased carbon dioxide solubility and an increased pH flows from the generation tank 1A to the carbon dioxide dissolution tank 4 via the circulation channel 52. In addition, carbon dioxide generated in the methane fermentation apparatus 2 flows into the carbon dioxide dissolution tank 4 via the carbon dioxide supply channel 53, so the solubility of carbon dioxide increases and the pH decreases in the carbon dioxide dissolution tank 4. Therefore, the water sent from the carbon dioxide dissolution tank 4 to the generation tank 1A via the circulation channel 52 has a high carbon dioxide solubility and a low pH. In other words, in the carbon dioxide dissolution tank 4, the carbon dioxide gas from the methane fermentation apparatus 2 comes into contact with the high pH water from the generation tank 1A, causing the carbon dioxide gas to dissolve and the pH of the high pH water to decrease. As a result of this treatment reaction, water with a high carbon dioxide solubility and a low pH is returned from the carbon dioxide dissolution tank 4 to the generation tank 1A. The carbon dioxide returned to the generator 1A is used for artificial chemical synthesis to produce organic matter in the generator 1A.

[0023] The energy generation system described above was a system that produced methane as an energy material, but as shown in Figure 1, by incorporating the methane power generation device 3 into this system, the energy generation system becomes a system that generates electrical energy. The chemical reaction equation for the energy output of the methane power generation device 3 is shown in (3) of Figure 1, [ka] Therefore, methane is burned by oxygen, producing carbon dioxide and water, and releasing 802 kJ of thermal energy. This thermal energy is converted into rotational power, generating electricity.

[0024] The methane power generation device 3 is equipped with either a methane combustion gas turbine generator or a methane combustion reciprocating engine generator to generate electricity using methane produced in the methane fermentation device 2. The methane required for methane combustion is supplied by a methane supply channel 54 connecting the methane fermentation device 2 and the methane power generation device 3, and the oxygen required for methane combustion is supplied by an oxygen supply channel 55 connecting the methane power generation device 3 and the organic matter production device 1. In other words, the methane required for methane combustion is produced by the methane fermentation device 2, and the oxygen required for methane combustion is produced by the organic matter production device 1. Furthermore, the carbon dioxide generated in the methane power generation device 3 is sent to the carbon dioxide dissolution tank 4 via a carbon dioxide supply channel 56 connecting the methane power generation device 3 and the carbon dioxide dissolution tank 4. As a result, this energy creation system is efficient and carbon neutral.

[0025] In a specific embodiment of the present invention, the organic matter generation device 1 is configured to produce organic matter using the gill cells of a white clam that harbors chemosynthetic bacteria. The white clam harbors sulfur-oxidizing bacteria, a type of chemosynthetic bacteria, in symbiosis within its gill cells. When the white clam buries its body in the seabed of a spring-fed area and extends its tentacles, the absorbed hydrogen sulfide is transported to its gills, and organic matter is synthesized (produced) by the symbiotic bacteria utilizing this hydrogen sulfide. The organic matter generation device 1 employs this organic matter synthesis process.

[0026] In the organic matter production apparatus 1 using the white clam, an immersion-type membrane separator (hereinafter simply referred to as the membrane separator) 10 is used, which is immersed in the production tank 1A, in order to efficiently bring hydrogen sulfide into contact with the gill cells of the white clam and promote the production of organic matter (glucose). As schematically shown in Figure 2, gill cells are cultured on the membrane of the membrane separator 10, and hydrogen sulfide gas is flowed into the filter chamber 11 formed between the membrane and the membrane coating. Water is supplied to the production tank 1A so that water (seawater or water with the required amount of dissolved carbon dioxide) flows outside the membrane on which the gill cells are cultured. A hydrogen sulfide supplyer 12 is provided upstream of the filter chamber 11 in order to supply hydrogen sulfide gas to the filter chamber 11.

[0027] The chemical reaction equation for artificial chemosynthesis by contact between hydrogen sulfide and the gill cells of the white clam in the organic matter production apparatus 1 using the white clam is shown in Figure 2 (1), [ka] Therefore, hydrogen sulfide, carbon dioxide, oxygen, and water combine to form organic matter (glucose), oxygen, water, and sulfur, producing organic matter.

[0028] Furthermore, the organic matter (glucose) produced in the organic matter generation device 1 using the clam *Clavaria* is contained in the gill cells that detach from the membrane of the membrane separation device 10. These detached gill cells are supplied to the methane fermentation device 2 via the gill cell supply channel 57, which serves as an organic matter transfer channel 51 connecting the generation tank 1A and the methane fermentation device 2. The gill cell supply channel 57 can supply the methane fermentation device 2 with a fluid containing gill cells that symbiotically harbor sulfur-oxidizing bacteria that produce organic matter. Adopting such a configuration makes it possible to operate this energy generation system submerged in the ocean, especially in the deep sea. Moreover, by incorporating a methane power generation device 3 into this system, a deep-sea power generation unit 6 (see Figure 4) is realized, which integrates the organic matter generation device 1, the methane fermentation device 2, and the methane power generation device 3. The deep-sea power generation unit 6 can supply power to facilities on land via a submarine power cable 62 (see Figure 4).

[0029] Figure 4 shows a conceptual diagram of an energy generation system using a deep-sea power generation unit 6. The deep-sea power generation unit 6 is connected to a relay station 60 floating on the sea surface by a connecting cable 61 and floats in the deep sea where clams (Clavaria nigricans) live and hydrogen sulfide is generated. Clams are captured by a clam capture device (not shown) and brought up to the relay station 60, after which their gill cells are cultured in the membrane of a replacement membrane separator 10. When the membrane separator 10 of the deep-sea power generation unit 6 is brought up for maintenance, it is replaced with a new membrane separator 10 containing cultured gill cells.

[0030] If the amount of hydrogen sulfide generated in the deep sea is insufficient to meet the desired organic matter production volume, hydrogen sulfide generated on land is transported by transport ship 7 to relay station 60, and from there supplied to the deep-sea power generation unit 6 via connecting cable 61. If the amount of carbon dioxide generated by the methane fermentation unit 2 and methane power generation unit 3 of the deep-sea power generation unit 6 exceeds the amount used by the organic matter generation unit 1, the remaining carbon dioxide may be stored in the deep sea.

[0031] The electricity generated by the deep-sea power generation unit 6 is transmitted to land via connecting cables 61, relay stations 60, and submarine power cables 62. However, if the electricity demand falls below the amount of electricity generated by the deep-sea power generation unit 6, the methane produced by the methane fermentation unit 2 is liquefied and stored in a storage tank. In this case, the pressure of the deep sea can be used as the pressure required for liquefaction of the methane. This realizes an efficient power generation system that adapts to electricity demand.

[0032] More specifically, the deep-sea power generation unit 6 is positioned near the habitat of the deep-sea clam, and, for example, a robotic arm is used to collect the clams from their habitat and supply them to the organic matter generation device 1. Furthermore, by introducing the clams or their gill cells into the membrane of the membrane separation device 10 along with seawater, the clam gill cells are cultured on the membrane. By incorporating the organic matter produced therein into the methane fermentation device 2, the deep-sea power generation unit 6 obtains all the materials necessary for the production of organic matter, such as hydrogen sulfide, clams, carbon dioxide, and water, from the deep sea, thus becoming a power generation system that contributes to carbon neutrality. In addition to the robotic arm, various other forms such as suction ducts can be used to deliver the clams or their gill cells into the membrane of the membrane separation device 10.

[0033] [Another embodiment] (1) In the above-described embodiment, sulfur-oxidizing bacteria were used as chemosynthetic bacteria that synthesize organic carbon compounds without sunlight, but instead, sulfur-oxidizing bacteria, nitrifying bacteria, iron bacteria, hydrogen bacteria, etc. may be used.

[0034] (2) In the embodiments described above, a flow path was used for the supply or discharge of hydrogen sulfide, oxygen, carbon dioxide, organic matter, and methane. However, a configuration in which these are transported in batches using a primary storage container or the like may be adopted at least partially.

[0035] (3) In the embodiments described above, the deep-sea power generation unit 6 is configured to actually float in the deep sea. However, if the deep-sea power generation unit 6 is configured to be housed in a container that creates a deep-sea environment in which hydrogen sulfide is supplied, then such a deep-sea power generation unit 6 can also be operated on land.

[0036] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. Moreover, the embodiments disclosed herein are illustrative, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the object of the present invention. [Industrial applicability]

[0037] This invention is applicable to an energy generation system that generates energy materials from organic matter produced using chemosynthetic bacteria. [Explanation of symbols]

[0038] 1:Organic matter generator 1A: Generation tank 2: Methane fermentation apparatus 3: Methane power generation equipment 4: Carbon dioxide dissolution tank 6: Deep-sea power generation unit 7: Transport ship 10: Membrane separation device 11: Filter chamber 12: Hydrogen sulfide supply unit 50: Hydrogen sulfide supply route 51: Organic material transfer path 52: Circulation channel 53: Carbon dioxide supply channels 54: Methane supply routes 55: Oxygen supply line 56: Carbon dioxide supply channels 57 :Gill cell supply channel 60: Relay Station 61: Connection cable 62: Submarine power cable

Claims

1. An organic matter production device that produces organic matter from chemosynthetic bacteria, carbon dioxide, and hydrogen sulfide, An energy generation system comprising a methane fermentation apparatus for fermenting the organic matter recovered from the organic matter generation apparatus.

2. The energy generation system according to claim 1, wherein the organic matter generation device produces the organic matter using gill cells of a clam that holds the chemosynthetic bacteria.

3. The energy generation system according to claim 2, wherein the organic matter generating device is located in the deep sea, which is the habitat of the white clam.

4. The energy generation system according to claim 2, wherein the organic matter generation device has an immersion-type membrane separation device, and the gill cells are attached to the immersion-type membrane separation device.

5. The energy generation system according to claim 4, wherein a hydrogen sulfide supply is provided to the immersion type membrane separation apparatus, and the immersion type membrane separation apparatus is immersed in water.

6. The energy generation system according to claim 4, wherein the immersion type membrane separation device is installed in a water-filled generation tank.

7. The energy creation system according to any one of claims 1 to 6, further comprising a power generation device that generates electricity using methane produced in the methane fermentation device.

8. The energy generation system according to claim 7, wherein the oxygen generated in the organic matter generating device is supplied to the power generation device.

9. The energy generation system according to claim 7, wherein at least a portion of the carbon dioxide generated by the methane fermentation apparatus and the power generation apparatus is dissolved in a carbon dioxide dissolution tank which is circulated and connected to the production tank of the organic matter generation apparatus.

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