Carbon dioxide fixation system and carbon dioxide fixation method

Abstract

To provide a technology that enables the long-term fixation of carbon dioxide.SOLUTION: A carbon dioxide fixation system 1A includes a carbon dioxide fixation device 10 for cultivating algae, fish, and shellfish on land, a supply device 11 for supplying seawater containing carbon dioxide to the carbon dioxide fixation device 10, and a recovery device 12 for recovering at least some of the algae, fish, and shell fish that have absorbed carbon dioxide from the carbon dioxide fixation device 10, and a drainage device 13 that drains sea water from which carbon dioxide has been reduced back to the sea from the carbon dioxide fixation device 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a carbon dioxide fixation technology. [Background technology]

[0002] Conventionally, various marine products, including high-quality seafood, have been cultivated in aquariums. For example, a cultivation method has been proposed that enables virus-free land cultivation of oysters by feeding oyster larvae with microalgae cultivated using seawater containing deep ocean water and cultivating them in aquariums using seawater containing deep ocean water (Patent Document 1). In this method, seawater containing deep ocean water is supplied to the aquarium in a flow-through manner, thereby cultivating oysters in a nutrient-rich and pollution-free environment.

[0003] In addition to physical innovations in aquaculture methods, increased production or improved quality of fish and shellfish have also been achieved through improved breeding of marine products. For example, it has been proposed to administer salmon growth hormone to fish using the cyanobacterium Synechoccus, which produces salmon growth hormone (Patent Document 2). This involves creating a recombinant plasmid by introducing an Escherichia coli promoter and a salmon growth hormone gene into a plasmid derived from the cyanobacterium Synechoccus, and administering the transformed cyanobacterium Synechoccus to salmon.

[0004] Meanwhile, in recent years, global warming has become a problem, and as one of the countermeasures, fixation of carbon dioxide by culturing photosynthetic organisms has attracted attention. One such fixation technology, for example, is to supply carbon dioxide to a culture tank containing algae, and irradiate it with artificial light while controlling the wavelength and intensity to appropriate values, thereby efficiently fixing carbon dioxide in factory exhaust gases and the atmosphere (Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2016 / 129703 [Patent Document 2] Japanese Patent Application Publication No. 5-68572 [Patent Document 3] JP 2010-57485 A Summary of the Invention [Problem to be solved by the invention]

[0006] When carbon dioxide from exhaust gas or the atmosphere is immobilized in algae, for example, carbon dioxide is generated during decomposition or combustion during disposal. Therefore, the immobilization of carbon dioxide using algae is temporary and does not enable the immobilization of carbon dioxide over a long period of time.

[0007] Therefore, an object of the present invention is to provide a technique that enables fixation of carbon dioxide over a long period of time. [Means for solving the problem]

[0008] As a result of intensive research into solving the above problems, the inventors discovered that carbon dioxide can be fixed over a long period of time by feeding fish and shellfish with algae that have fixed carbon dioxide contained in seawater, and thus completed the present invention. That is, the present invention provides the following carbon dioxide fixation system and carbon dioxide fixation method.

[0009] [1] A carbon dioxide fixation device for cultivating algae and seafood on land; a supply device for supplying seawater containing carbon dioxide to the carbon dioxide fixation device; a recovery device that recovers at least a portion of the algae and seafood that have absorbed carbon dioxide from the carbon dioxide fixation device; a discharge device for discharging seawater containing reduced carbon dioxide from the carbon dioxide fixation device into the ocean; A carbon dioxide fixation system equipped with the device.

[0010] [2] Item 2. The carbon dioxide fixation system according to item 1, wherein the carbon dioxide fixation device fixes carbon dioxide contained in seawater in the algae, and feeds the algae with the carbon dioxide fixed therein to the fish and shellfish.

[0011] [3] Item 3. The carbon dioxide fixation system according to item 1 or 2, wherein the seafood includes shellfish.

[0012] [4] 4. The carbon dioxide fixation system according to any one of items 1 to 3, wherein the recovery device recovers shellfish in which carbon dioxide has been immobilized by accumulating carbon dioxide in the shells in the form of calcium carbonate.

[0013] [5] 5. The carbon dioxide fixation system according to any one of items 1 to 4, wherein the recovery device recovers fish in which carbon dioxide has been immobilized by accumulating it in the form of calcium carbonate in the fish bones.

[0014] [6] 6. The carbon dioxide fixation system according to any one of items 1 to 5, wherein the capture device captures carbon dioxide immobilized in the algae in the form of organic matter.

[0015] [7] 7. The carbon dioxide fixation system according to any one of items 1 to 6, further comprising a carbon dioxide concentration measuring device that measures a carbon dioxide concentration in the seawater supplied to the carbon dioxide fixation device by the supply device and a carbon dioxide concentration in the seawater discharged from the carbon dioxide fixation device by the drainage device.

[0016] [8] The carbon dioxide fixation device comprises: A first immobilization device for cultivating the algae; A second immobilization device for cultivating the fish and shellfish; a feeding apparatus that feeds the algae to the fish and shellfish as feed, the feeding apparatus including a connecting pipe that connects the first immobilization device and the second immobilization device, and that is capable of switching between supplying and not supplying a liquid from the first immobilization device to the second immobilization device through the connecting pipe; Item 8. The carbon dioxide fixation system according to any one of items 1 to 7, comprising:

[0017] [9] Cultivating algae and fish and shellfish on land; Supplying seawater containing carbon dioxide to the algae and the seafood; recovering at least a portion of the algae and seafood that have absorbed carbon dioxide; and discharging the seawater with reduced carbon dioxide into the ocean. A method for fixing carbon dioxide comprising the steps of:

[0018]

[10] Item 10. The method for fixating carbon dioxide according to Item 9, further comprising fixating carbon dioxide contained in seawater in the algae, and feeding the algae in which carbon dioxide has been fixed to the fish and shellfish.

[0019]

[11] Item 11. The method for fixation of carbon dioxide according to Item 9 or 10, wherein the seafood includes shellfish.

[0020]

[12] Item 12. The method for immobilizing carbon dioxide according to any one of Items 9 to 11, further comprising recovering shellfish in which carbon dioxide has been immobilized by accumulating the carbon dioxide in the form of calcium carbonate in the shells.

[0021]

[13] Item 13. The method for immobilizing carbon dioxide according to any one of Items 9 to 12, further comprising accumulating carbon dioxide in the form of calcium carbonate in fish bones, and recovering the immobilized fish.

[0022]

[14] Item 14. The method for fixation of carbon dioxide according to any one of Items 9 to 13, wherein carbon dioxide fixed in the algae in the form of an organic matter is recovered.

[0023]

[15] Item 15. The method for fixation of carbon dioxide according to any one of items 9 to 14, further comprising measuring a carbon dioxide concentration in the seawater supplied to the algae and the seafood, and a carbon dioxide concentration in the seawater discharged into the ocean.

[0024]

[16] Item 16. The method for fixation of carbon dioxide according to any one of Items 9 to 15, wherein the algae and the fish and shellfish are separately cultured, a liquid containing the algae and the seawater used for cultivating the algae is supplied to the fish and shellfish to feed the algae as feed, and supply and non-supply of the liquid to the fish and shellfish are switched.

[0025]

[17] Item 17. The carbon dioxide fixation method according to any one of items 9 to 16, further comprising evaluating the amount of carbon dioxide fixed by the cultivation of the algae and the fish and shellfish. Effect of the Invention

[0026] The present invention provides a technology that enables carbon dioxide to be fixed for a long period of time. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a block diagram of a carbon dioxide fixation system according to a first embodiment of the present invention. [Diagram 2] 2 is a block diagram showing an example of a carbon dioxide concentration measuring device that can be included in the system of FIG. 1. [Diagram 3] FIG. 3 is a block diagram of a carbon dioxide fixation system according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a block diagram showing an example of a carbon dioxide fixation amount evaluation device applicable to the system of FIG. [Diagram 5] FIG. 5 is a flowchart showing an operation flow of the system of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings referred to below, the same parts are given the same reference numerals, and duplicated explanations will be omitted. Note that the present invention is not limited to the following embodiment.

[0029] First Embodiment 1 is a block diagram of a carbon dioxide fixation system according to a first embodiment of the present invention. The carbon dioxide fixation system 1A includes a carbon dioxide fixation device 10, a supply device 11, a capture device 12, a drainage device 13, and a carbon dioxide concentration measurement device 14.

[0030] The carbon dioxide fixation apparatus 10 is installed on land. The carbon dioxide fixation apparatus 10 cultivates algae and also cultivates fish and shellfish using the algae as feed.

[0031] In the carbon dioxide fixation device 10, the algae absorb carbon dioxide in seawater during photosynthesis and fix it in their bodies. Fish and shellfish that feed on the algae fix the carbon dioxide in their bodies as shells and fish bones.

[0032] The carbon dioxide fixation apparatus 10 includes one or more culture tanks for cultivating algae and seafood. In the carbon dioxide fixation system 1A, both algae and seafood are cultivated in each culture tank.

[0033] The carbon dioxide fixation apparatus 10 may further include a water flow generating device that generates a water flow in the culture tank. The water flow generating device includes, for example, a pump.

[0034] The carbon dioxide fixation apparatus 10 may further include a temperature adjustment device. For example, when the temperature of the seawater in the culture tank exceeds or falls below a specified temperature range, the temperature adjustment device adjusts the temperature of the seawater in the culture tank by introducing seawater into the culture tank via the supply device 11.

[0035] According to one example, the carbon dioxide fixation apparatus 10 is configured to be capable of irradiating sunlight onto the algae or onto the algae and seafood. According to another example, the carbon dioxide fixation apparatus 10 further includes a lighting device that irradiates light onto the algae or onto the algae and seafood. According to yet another example, the carbon dioxide fixation apparatus 10 is configured to be capable of irradiating sunlight onto the algae or onto the algae and seafood, and further includes a lighting device that irradiates light onto the algae or onto the algae and seafood. The lighting device includes, for example, a light-emitting diode (LED) light source. When the wall of the culture tank is made of a transparent material, light from the sun or the lighting device can be irradiated onto the algae or seafood through the wall.

[0036] The algae can be selected from seaweeds and microalgae, depending on the preference of the fish and shellfish to be cultured. For example, the microalgae is a photosynthetic eukaryote, and is a unicellular organism or a colony thereof. The microalgae is, for example, a unicellular green alga such as Chlamydomonas reinhardtti, a unicellular red alga such as Cyanidioschyzon merolae, a heteroknot plant such as Phaeodactylum or Nannochloropsis, or a colony thereof. The microalgae may not be eukaryotic, but may be prokaryotic, for example, bacteria such as cyanobacteria. Preferably, the microalgae is Nannochloropsis or Synechococcus 7002, which have a high growth rate in seawater, i.e., a high ability to fix carbon dioxide. These algae fix carbon dioxide in the seawater they are supplied with through photosynthesis in the form of organic matter, such as fats and oils and carbohydrates.

[0037] In the cultivation of algae for immobilizing carbon dioxide, for example, seawater containing all nutrients necessary for algae growth and photosynthesis is used as a medium. The medium is, for example, a liquid medium. The cultivation conditions are, for example, suspension culture. The suspension culture can be carried out in an open culture tank, for example, called an open pond. The suspension culture may also be carried out in a closed system, for example, called a closed photobioreactor.

[0038] The seafood is, for example, at least one of shellfish and fish. Shellfish can fix carbon dioxide in the form of calcium carbonate in their shells by absorbing calcium from seawater or the like. Examples of shellfish that can be used include bivalves and pearl oysters used in pearl farming. Fish bones are mainly composed of calcium phosphate, but also contain 7% calcium carbonate. Therefore, carbon dioxide can be fixed in the form of calcium carbonate even when fish are farmed.

[0039] The fish and shellfish may have their carbon dioxide fixation ability enhanced by partial or complete deletion of a gene that inhibits the enhancement of carbon fixation ability. When such fish and shellfish are used, it is possible to increase the amount of carbon dioxide fixation compared to when ordinary fish and shellfish are used.

[0040] The supply device 11 supplies seawater containing carbon dioxide to the carbon dioxide fixation device 10. Specifically, the supply device 11 supplies seawater containing carbon dioxide to a culture tank of the carbon dioxide fixation device 10. When the carbon dioxide fixation device 10 includes a plurality of culture tanks, the supply device 11 supplies seawater to these culture tanks separately, for example. When a plurality of culture tanks are connected in series, the supply device 11 may supply seawater to the most upstream culture tank.

[0041] The supply device 11 may include, for example, a pump that sends seawater from the ocean to the carbon dioxide fixation device 10. The supply device 11 may further include a purification device, which can purify the seawater containing general bacteria and pollutants.

[0042] The ocean absorbs carbon dioxide from the atmosphere. Surface water of the ocean is in contact with the atmosphere and therefore contains more carbon dioxide than deep sea water. Therefore, it is preferable that the seawater supplied by the supply device 11 to the carbon dioxide fixation device 10 is surface water of the ocean.

[0043] The recovery device 12 recovers at least a portion of the algae and seafood that have absorbed carbon dioxide from the carbon dioxide fixation device 10. For example, the recovery device 12 recovers one or more of shellfish in which carbon dioxide has been immobilized by accumulating it in the form of calcium carbonate in their shells, fish in which carbon dioxide has been immobilized by accumulating it in the form of calcium carbonate in their fishbone, and algae in which carbon dioxide has been immobilized in the form of organic matter. When the carbon dioxide fixation device 10 includes a plurality of culture tanks, the recovery device 12 may recover at least a portion of the algae and seafood from only a portion of these culture tanks, or may recover at least a portion of the algae and seafood from all of these culture tanks.

[0044] When collecting fish, the collecting device 12 can include, for example, a net or a cage for catching the fish. When collecting shellfish that have been cultured in a net or a cage or supported by a rope or the like, the collecting device 12 can include, for example, a lifting device for lifting them. When collecting algae, the collecting device 12 can include, for example, a centrifuge device.

[0045] At least a portion of the collected seafood can be used as a resource, for example, as food or processed products or raw materials thereof. For example, shells can be used as materials for crafts. Furthermore, calcium carbonate contained in seafood can be used as raw materials for crafts or as fertilizer. Furthermore, as described above, algae that have absorbed carbon dioxide are fed to seafood, but surplus algae may be produced. Such algae can also be collected and used as a resource, for example, as food or processed products or raw materials thereof.

[0046] The drainage device 13 discharges the seawater from which the carbon dioxide has been reduced in the carbon dioxide fixation device 10 into the ocean. The drainage device 13 includes, for example, a flow path that guides the seawater from the carbon dioxide fixation device 10 into the ocean. The drainage device 13 may further include a pump. When the recovery device 12 includes a device that separates the algae and the seawater, such as a centrifuge device, the drainage device 13 may be capable of discharging the seawater separated from the algae into the ocean. When the carbon dioxide fixation device 10 includes multiple culture tanks, the drainage device 13 may discharge seawater from only some of these culture tanks into the ocean, or may discharge seawater from all of these culture tanks into the ocean.

[0047] The carbon dioxide concentration measuring device 14 is connected to the supply device 11 and the drainage device 13. The carbon dioxide concentration measuring device 14 measures the carbon dioxide concentration in the seawater supplied to the carbon dioxide fixation device 10 by the supply device 11 and the carbon dioxide concentration in the seawater discharged from the carbon dioxide fixation device 10 by the drainage device 13. By comparing these carbon dioxide concentrations, the amount of carbon dioxide fixation per unit volume can be quantitatively evaluated.

[0048] FIG. 2 is a block diagram showing an example of a carbon dioxide concentration measuring device that may be included in the system of FIG.

[0049] The carbon dioxide concentration measuring device 14 shown in FIG. 2 includes an equilibrator 20, an infrared analyzer 21, a liquid sample supplying device 22, a drying device 23, a standard gas generator 24, and a gas sample supplying device 25.

[0050] The equilibrator 20 includes a container capable of storing seawater and a shower head capable of spraying seawater from the top of the container toward the bottom of the container. The equilibrator 20 brings the seawater sprayed by the shower head into gas-liquid contact with the air in the container. The equilibrator 20 creates an equilibrium state in which the movement of carbon dioxide molecules between the seawater and the air has apparently ceased. Instead of the shower head, the equilibrator 20 may include another structure for efficiently bringing the air and seawater into gas-liquid contact, such as a nozzle head that ejects seawater from the top of the container toward the bottom of the container, and one or more plates that collide with the seawater ejected by the nozzle head to generate seawater splashes.

[0051] The liquid sample supplying device 22 supplies seawater, the carbon dioxide concentration of which is to be measured, into the container of the equilibrator 20 via the shower head.

[0052] The gas sample supply device 25 supplies atmospheric air to the drying device 23 .

[0053] The drying device 23 is connected to the gas sample supplying device 25 and the equilibrator 20. The drying device 23 dries a mixed gas of the gas supplied from the equilibrator 20 and the air supplied from the gas sample supplying device 25.

[0054] The infrared analyzer 21 is, for example, a non-dispersive infrared analyzer. The infrared analyzer 21 is connected to the dryer 23 and the equilibrator 20, and the mixed gas can be circulated in a circulation path including the dryer 23, the infrared analyzer 21, and the equilibrator 20. The infrared analyzer 21 is also configured to be able to exhaust a part of the mixed gas into the atmosphere.

[0055] In this way, by making the carbon dioxide concentration measuring device 14 an open system, it is possible to reduce measurement errors resulting from pressure fluctuations. Note that the amount of air supplied to the drying device 23 by the gas sample supplying device 25 and the amount of mixed gas discharged to the atmosphere by the infrared analyzer 21 are made sufficiently smaller than the amount of mixed gas circulated through the above-mentioned circulation path.

[0056] The carbon dioxide concentration measuring device 14 performs the measurements on the gas supplied from the equilibrator 20 as described above, while also performing the following measurements.

[0057] That is, the supply of gas from the equilibrator 20 to the drying device 23 and the supply of air from the gas sample supply device 25 to the drying device 23 are stopped. Then, the gas generated by the standard gas generator 24 is supplied to the drying device 23.

[0058] The standard gas generator 24 generates a standard gas with a known carbon dioxide concentration. The infrared analyzer 21 performs measurements on the standard gas. The infrared analyzer 21 then compares the results of the measurements performed on the mixed gas with the results of the measurements performed on the standard gas to determine the carbon dioxide concentration in the mixed gas.

[0059] When carbon dioxide dissolves in seawater, most of it turns into bicarbonate ions (HCO3 - ) and carbonate ions (CO3 2- The carbon dioxide concentration obtained by the above method is the total concentration of carbon dioxide present in seawater in its original state and these ions.

[0060] The carbon dioxide concentration measuring device 14 may have another configuration. Although the system described with reference to Fig. 2 can directly measure the carbon dioxide concentration, it is necessary to use a large-scale device and measurement method. To eliminate such troublesomeness, the amount of immobilized carbon dioxide may be estimated from the increase in the mass of the shell or fish bone and the mass ratio of carbonate ions in the shell or fish bone.

[0061] As an example of the carbon dioxide fixation method of the present embodiment, a carbon dioxide fixation method using diatoms and pearl oysters as algae and seafood, respectively, will be described. Note that this method is merely an example, and the present invention is not limited thereto.

[0062] In the carbon dioxide fixation system 1A, seawater is pumped up from the ocean by a supply device 11 and introduced into a culture tank of a carbon dioxide fixation device 10. Diatoms to be cultured are introduced into the culture tank filled with seawater. The form of the diatoms to be introduced is not particularly limited, and may be, for example, cells growing by asexual reproduction, or may be in a state in which gametes are formed by sexual reproduction. Pearl oysters are further introduced into the culture tank into which the diatoms have been introduced. The form of the pearl oysters to be introduced is not particularly limited, and may be, for example, juvenile or adult. The culture tank is irradiated with sunlight to cultivate the diatoms and pearl oysters. The breeding conditions are not particularly limited, and can be determined appropriately depending on the types of algae and seafood to be cultured.

[0063] When the cultivation of the algae and seafood in the carbon dioxide fixation apparatus 10 is completed, a recovery device 12 connected to the carbon dioxide fixation apparatus 10 recovers the cultivated diatoms and pearl oysters. In addition, a drainage device 13 connected to the carbon dioxide fixation apparatus 10 discharges seawater from the culture tank of the carbon dioxide fixation apparatus 10.

[0064] The amount of carbon dioxide fixed in the collected diatoms and pearl oysters can be estimated, for example, from the increase in the mass of the shells and the mass ratio of carbonate ions in the shells. Furthermore, by measuring the carbon dioxide concentrations in the seawater supplied to the carbon dioxide fixation device 10 and in the seawater discharged from the carbon dioxide fixation device 10, it is possible to confirm the extent to which the carbon dioxide concentration has decreased.

[0065] As described above, in this embodiment, the algae absorbs carbon dioxide in seawater during the photosynthesis process and fixes it in the algae's body. Then, the algae is fed to fish and shellfish, and carbon dioxide is fixed in the algae's body as shells and fish bones. In this way, the carbon dioxide is fixed in the form of hard tissues of fish and shellfish such as shells and bones, so that it can be used as a resource, and can be passed on to the next carbon cycle without any waste, and carbon dioxide is not released back into the atmosphere. Therefore, according to this embodiment, carbon dioxide can be fixed for a long period of time.

[0066] As described above, the amount of immobilized carbon dioxide can be estimated from the increase in the mass of shells and fish bones and the mass ratio of carbonate ions in the shells and fish bones. The amount of immobilized carbon dioxide can also be estimated from the mass and cell count of algae eaten by fish and shellfish. In this way, it is possible to quantitatively visualize the reduction in carbon dioxide dissolved in seawater.

[0067] Furthermore, in this embodiment, the carbon dioxide dissolved in the seawater is fixed, and the seawater with a reduced carbon dioxide concentration is discharged into the ocean. Seawater absorbs large amounts of carbon dioxide from the atmosphere. When seawater with a reduced carbon dioxide concentration is discharged into the ocean, the mass of carbon dioxide that can dissolve in the ocean increases. Therefore, according to this embodiment, carbon dioxide in the atmosphere can also be reduced, which helps to suppress global warming.

[0068] <Second embodiment> Fig. 3 is a block diagram of a carbon dioxide fixation system according to a second embodiment of the present invention. The carbon dioxide fixation system 1B shown in Fig. 3 is similar to the carbon dioxide fixation system 1A except that the following configuration is adopted.

[0069] That is, in the carbon dioxide fixation system 1B, the carbon dioxide fixation apparatus 10 includes a first fixation apparatus 110 for cultivating algae, a second fixation apparatus 120 for cultivating seafood, and a feeding apparatus 130 for feeding the algae to the seafood as feed.

[0070] The first immobilization device 110 may include only one culture tank for cultivating algae, or may include multiple culture tanks. In the latter case, the culture stages of the algae may be different between the culture tanks. In this case, for example, algae at an optimal culture stage for cultivating seafood can be fed to seafood.

[0071] Similarly, the second immobilization device 120 may include only one culture tank for cultivating seafood, or may include multiple culture tanks. In the latter case, the culture stages of the seafood may be different between the culture tanks. If the optimal culture stage of algae to be used as food for seafood varies depending on the culture stage of the seafood, then by varying the culture stage of the algae between the algae culture tanks and varying the culture stage of the seafood between the seafood culture tanks, the seafood can be fed with algae at the optimal culture stage for the seafood depending on its culture stage.

[0072] For example, the feeding device 130 collects the algae that has immobilized carbon dioxide from the first immobilization device 110, dries it, and then provides it as feed to the fish and shellfish in the second immobilization device 120. For example, the feeding device 130 separates the algae in the first immobilization device 110 from the seawater by centrifugation, dries it, and then provides it as feed to the fish and shellfish in the second immobilization device 120.

[0073] It is preferable that the feeding device 130 includes a connecting pipe connecting the first immobilization device 110 and the second immobilization device 120, and is capable of switching between supplying and not supplying liquid from the first immobilization device 110 to the second immobilization device 120 through this connecting pipe. The liquid supplied from the first immobilization device 110 to the second immobilization device 120 may or may not be concentrated. In either case, since there is no drying process, efficient feeding to seafood is possible.

[0074] In the carbon dioxide fixation system 1B, the supply device 11 may introduce seawater into both the culture tank of the first immobilization device 110 and the culture tank of the second immobilization device 120. Alternatively, the supply device 11 may introduce seawater only into the culture tank of the first immobilization device 110, and introduce seawater discharged from the culture tank of the first immobilization device 110 into the culture tank of the second immobilization device 120. In the latter case, the amount of seawater introduced into the culture tank of the first immobilization device 110 can be increased compared to the former case, and the seawater with a reduced carbon dioxide concentration can be used as breeding water for fish and shellfish, so that carbon dioxide in the seawater can be fixed more efficiently.

[0075] As an example of the carbon dioxide fixation method of the present embodiment, a carbon dioxide fixation method using diatoms and pearl oysters as algae and seafood, respectively, will be described. Note that this method is merely an example, and the present invention is not limited thereto.

[0076] In the carbon dioxide fixation system 1B, seawater is pumped up from the ocean by the supply device 11 and introduced into the culture tank of the carbon dioxide fixation device 10. For example, the supply device 11 introduces seawater only into the culture tank of the first fixation device 110. Next, diatoms to be cultivated are introduced into the culture tank of the first fixation device 110. Sunlight is irradiated onto this culture tank to cultivate the diatoms.

[0077] Next, the feeding device 130 introduces the liquid containing diatoms and seawater from the culture tank of the first immobilization device 110 through a connecting pipe into the culture tank of the second immobilization device 120. Next, pearl oysters are introduced into the culture tank of the second immobilization device 120. Sunlight is also irradiated into this culture tank to cultivate the pearl oysters.

[0078] When the cultivation of the algae and seafood in the carbon dioxide fixation apparatus 10 is completed, a recovery device 12 connected to the carbon dioxide fixation apparatus 10 recovers the cultivated diatoms and pearl oysters. In addition, a drainage device 13 connected to the carbon dioxide fixation apparatus 10 discharges seawater from the culture tank of the second fixation apparatus 120. The drainage device 13 may discharge seawater only from the culture tank installed at the most downstream position in the carbon dioxide fixation apparatus 10, or may discharge seawater from multiple culture tanks.

[0079] The amount of carbon dioxide fixed in the collected diatoms and pearl oysters can be estimated, for example, from the increase in the mass of the shells and the mass ratio of carbonate ions in the shells. Furthermore, by measuring the carbon dioxide concentrations in the seawater supplied to the carbon dioxide fixation device 10 and in the seawater discharged from the carbon dioxide fixation device 10, it is possible to confirm the extent to which the carbon dioxide concentration has decreased.

[0080] In this embodiment, as in the first embodiment, it is possible to fix carbon dioxide for a long period of time. In addition, in this embodiment, it is possible to quantitatively visualize the amount of carbon dioxide dissolved in seawater that has been reduced. Furthermore, this embodiment also reduces carbon dioxide in the atmosphere, which helps to suppress global warming.

[0081] <Modification> Various modifications are possible to the above-mentioned carbon dioxide fixation systems 1A and 1B. For example, the carbon dioxide fixation system 1B may further include a carbon dioxide fixation amount evaluation device.

[0082] Fig. 4 is a block diagram showing an example of a carbon dioxide fixation amount evaluation device applicable to the systems of Fig. 1 and Fig. 3. Fig. 5 is a flowchart showing an operation flow of the systems of Fig. 1 and Fig. 3.

[0083] The carbon dioxide fixation amount evaluation device 15 shown in Fig. 4 includes an elemental analysis device 31, an algae culture liquid volume measurement device 32, an algae extraction device 33, and a predation rate calculation device 35. In addition, according to one example, the feeding device 34 corresponds to the feeding device 130 in Fig. 3.

[0084] The carbon dioxide fixation amount evaluation device 15 first extracts a liquid containing algae and seawater (hereinafter referred to as an algae-containing culture liquid) from the first fixation device 110 to be supplied to the second fixation device 120 (step S1). The elemental analysis device 31 measures the amount of carbon X (g / L) per volume of the algae-containing culture liquid (step S2). The algae culture liquid amount measurement device 32 measures the amount Y, here the volume (L), of the algae-containing culture liquid to be supplied from the first fixation device 110 to the second fixation device 120 (step S3).

[0085] The algae extraction device 33 extracts algae from the amount Y of the algae-containing culture solution (step S4). The feeding device 34 feeds the entire amount of algae extracted by the algae extraction device 33 to the fish and shellfish in the second immobilization device 120 (step S5). The algae extraction device 33 can be omitted. In this case, the feeding device 34 feeds the amount Y of the algae-containing culture solution to the fish and shellfish in the second immobilization device 120.

[0086] The predation rate calculation device 35 calculates the predation rate Z by the fish and shellfish after a unit time has elapsed since the feeding device 34 fed the algae to the fish and shellfish (step S6).

[0087] The carbon dioxide fixation amount evaluation device 15 calculates the amount of carbon fixation per unit time from the amount of carbon X per volume of the algae-containing culture solution, the amount of algae-containing culture solution Y, and the predation rate Z (step S7). That is, the product XYZ of X, Y, and Z is obtained as the amount of carbon fixation per unit time.

[0088] It should be noted that the present invention is not limited to the above-described embodiments, and it is apparent that many modifications and combinations are possible within the scope of the technical concept of the present invention by a person having ordinary knowledge in the art. [Explanation of symbols]

[0089] 1A…Carbon dioxide fixation system 1B…Carbon dioxide fixation system 10...Carbon dioxide fixation device 11…Feeding device 12...Recovery device 13...Drainage device 14...Carbon dioxide concentration measuring device 15…Carbon dioxide fixation evaluation device 20...Balancer 21…Infrared analyzer 22...Liquid sample supply device 23...Drying device 24...Standard gas generator 25...Gas sample supply device 31...Elemental analyzer 32…Algae culture liquid volume measuring device 33...Algae extraction device 34...Feeding device 35...Predation rate calculation device 110...First immobilization device 120…Second immobilization device 130...Feeding device

Claims

1. A carbon dioxide fixation device for cultivating algae and seafood on land; a supply device for supplying seawater containing carbon dioxide to the carbon dioxide fixation device; a recovery device that recovers at least a portion of the algae and seafood that have absorbed carbon dioxide from the carbon dioxide fixation device; a discharge device for discharging seawater containing reduced carbon dioxide from the carbon dioxide fixation device into the ocean; Equipped with The carbon dioxide fixation device comprises: A first immobilization device for cultivating the algae and immobilizing carbon dioxide contained in seawater in the algae; A second immobilization device for cultivating the fish and shellfish; a feeding device that recovers the algae with the carbon dioxide immobilized therein from the first immobilization device, dries the algae, and then feeds the algae to the fish and shellfish in the second immobilization device; A carbon dioxide fixation system equipped with the device.

2. The carbon dioxide fixation system according to claim 1 , wherein the seafood includes shellfish.

3. 3. The carbon dioxide fixation system according to claim 1 or 2, wherein the recovery device recovers shellfish in which carbon dioxide has been immobilized by accumulating it in the form of calcium carbonate in the shells.

4. 4. The carbon dioxide fixation system according to claim 1, wherein the recovery device recovers the fish in which carbon dioxide has been immobilized by accumulating carbon dioxide in the form of calcium carbonate in the fish bones.

5. 5. The carbon dioxide fixation system according to claim 1, wherein the capture device captures carbon dioxide that has been immobilized in the algae in the form of organic matter.

6. 6. The carbon dioxide fixation system according to claim 1, further comprising a carbon dioxide concentration measuring device that measures the carbon dioxide concentration in the seawater supplied to the carbon dioxide fixation device by the supply device and the carbon dioxide concentration in the seawater discharged from the carbon dioxide fixation device by the drainage device.

7. Cultivating algae and fish and shellfish on land; Supplying seawater containing carbon dioxide to the algae and the seafood; recovering at least a portion of the algae and seafood that have absorbed carbon dioxide; and discharging the seawater with reduced carbon dioxide into the ocean. Including, The carbon dioxide fixation method includes separately cultivating the algae and the seafood, fixing carbon dioxide contained in seawater in the algae, drying the algae with the fixed carbon dioxide, and then feeding the algae to the seafood.

8. The carbon dioxide fixation method according to claim 7, wherein the seafood includes shellfish.

9. 9. The method for immobilizing carbon dioxide according to claim 7 or 8, wherein carbon dioxide is accumulated in shells in the form of calcium carbonate, and the shellfish in which carbon dioxide has been immobilized are recovered.

10. 10. The method for immobilizing carbon dioxide according to claim 7, wherein the carbon dioxide is accumulated in the fish bones in the form of calcium carbonate, and the fish in which the carbon dioxide is immobilized are collected.

11. 11. The method for fixation of carbon dioxide according to claim 7, wherein carbon dioxide fixed in the algae in the form of an organic matter is recovered.

12. The carbon dioxide fixation method according to any one of claims 7 to 11, further comprising measuring the carbon dioxide concentration in the seawater supplied to the algae and the seafood, and the carbon dioxide concentration in the seawater discharged into the ocean.

13. The carbon dioxide fixation method according to any one of claims 7 to 12, further comprising evaluating an amount of carbon dioxide fixed by the cultivation of the algae and the fish and shellfish.

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