Marine environment improvement method and calcium ion supply device used for same

Abstract

Provided are: a marine environment improvement method capable of reducing greenhouse gas by absorbing carbon dioxide and improving a marine environment; and a calcium ion supply device used for the same. The marine environment improvement method involves: supplying lime water or calcium carbonate and water to a reaction tank 10; supplying atmosphere A into the reaction tank 10; causing a reaction in the reaction tank 10; and supplying, to the sea S, an aqueous solution of obtained calcium hydrogen carbonate. A calcium ion supply device 1 includes the reaction tank 10, a supply device 2, a gas-liquid contact device 3, a conveyance device 4, and a control device 5 for controlling each of the devices.

Description

Marine environment improvement method and calcium ion supply device used therein

[0001] The present invention relates to a marine environment improvement method that can reduce carbon dioxide emissions, and a calcium ion supply device used therein.

[0002] Currently, efforts are being made worldwide to reduce carbon dioxide emissions in order to prevent global warming.

[0003] One of the techniques proposed to reduce the concentration of carbon dioxide in the atmosphere is to capture carbon dioxide from the exhaust gas outlets of factories and other facilities, and then mineralize and fix the captured carbon dioxide underground. A storage facility for this technology has already been demonstrated (see, for example, Non-Patent Document 1).

[0004] Another proposed technology involves recovering carbon dioxide from the atmosphere, dissolving the recovered carbon dioxide in water, injecting it into the ground, allowing it to be absorbed and fixed in the ground, and then recovering hot spring water (see, for example, Patent Document 1).

[0005] IPCC (2005) Special Report on Carb on Dioxide Capture and Storage: Prepared by Working Group III of the International Panel on Climate Change. Cambridge University Press, Cambridge and New York, 422 pp. Special table 2017-528318 publication

[0006] However, when recovering carbon dioxide from the exhaust gas outlet, it is not possible to recover carbon dioxide that has already been released and diffused into the atmosphere.

[0007] Furthermore, whether capturing carbon dioxide from exhaust gas outlets or from the atmosphere, it is mineralized and fixed underground, and in both cases, it is thought that the calcium oxide contained in the basalt that makes up the Earth's crust reacts with carbon dioxide to form calcium carbonate, which is fixed underground. However, if carbon dioxide is directly transported from the atmosphere into the ground and mineralized and fixed in this way, while it may be possible to achieve the goal when considering only carbon dioxide reduction, it is far removed from the carbon dioxide reduction mechanism that the natural environment originally played, and so other issues arise, and there is concern that it will take time to improve the marine environment, which has been deteriorated by the increase in atmospheric carbon dioxide.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a marine environment improvement method that can absorb carbon dioxide to reduce greenhouse gases and improve the marine environment, and a calcium ion supply device to be used therein.

[0009] In order to solve the above problems, the marine environment improvement method of the present invention comprises supplying limewater or calcium carbonate and water to a reaction tank, supplying air into the reaction tank, causing carbon dioxide in the air to react with the limewater or calcium carbonate and water in the reaction tank, and supplying the resulting aqueous solution of calcium bicarbonate to the sea.

[0010] In the above-described method for improving the marine environment, carbon dioxide in the atmosphere may be reacted with lime water or calcium carbonate and water in the reaction tank while the aqueous solution in the reaction tank is cooled.

[0011] In the marine environment improvement method, the limewater may be prepared by adding water to calcium oxide obtained by burning calcium carbonate in a closed system using renewable energy to recover carbon dioxide, or by adding water to calcium hydroxide obtained by slaked calcium oxide.

[0012] In the marine environment improvement method, the calcium carbonate may be obtained by burning calcium carbonate in a closed system using renewable energy to recover carbon dioxide, and then allowing the calcium oxide obtained to absorb carbon dioxide from the atmosphere, or by digesting the calcium oxide to obtain calcium hydroxide, and then allowing carbon dioxide from the atmosphere to absorb carbon dioxide.

[0013] The marine environment improvement method of the present invention, which solves the above-mentioned problems, involves calcining calcium carbonate in a closed system using renewable energy, recovering carbon dioxide, and adding water to the calcium oxide obtained to prepare limewater, or adding water to calcium hydroxide obtained by slaked the calcium oxide, and supplying the resulting limewater to the sea.

[0014] In the marine environment improvement method, each step may be carried out using renewable energy.

[0015] In the above-mentioned marine environment improvement method, the calcium carbonate may be obtained from seashells.

[0016] In the marine environment improvement method, limestone may be used as calcium carbonate.

[0017] In the above-mentioned method for improving the marine environment, the water used to prepare the lime water may be groundwater, stored water, rainwater, river water, or industrial wastewater.

[0018] In the above-mentioned marine environment improvement method, the obtained aqueous solution of calcium hydrogen carbonate may be supplied to sandy areas on the seabed.

[0019] In the above-mentioned marine environment improvement method, the obtained limewater may be supplied to sandy areas in the sea.

[0020] In the above marine environment improvement method, the obtained limewater may be supplied to the seabed.

[0021] A calcium ion supply device of the present invention for solving the above-mentioned problems includes a reaction tank that can be filled with lime water or calcium carbonate and water, a supply device that supplies lime water or water to the reaction tank, a gas-liquid contactor that has a pump that collects air and brings the air into contact with the lime water or calcium carbonate and water filled in the reaction tank, a transport device that transports an aqueous solution of calcium bicarbonate produced by the reaction of carbon dioxide in the air with the lime water or calcium carbonate and water from the reaction tank to the outside using a transport pump, and transports the aqueous solution of calcium bicarbonate to the sea via a transport path connected to the transport pump, and a control device that controls each of these devices.

[0022] The calcium ion supply device may further include a water temperature control device that controls the temperature of the aqueous solution in the reaction tank.

[0023] The calcium ion supply device may further include a renewable energy supply device that produces renewable energy and supplies the renewable energy to the device.

[0024] As described above, according to the present invention, calcium can be supplied to the ocean in the form of calcium ions by supplying limewater or calcium carbonate and water to a reaction tank, supplying atmospheric air to the aqueous solution in the reaction tank, reacting carbon dioxide in the air with the aqueous solution, and supplying the resulting aqueous solution of calcium bicarbonate to the ocean. Normally, atmospheric carbon dioxide dissolves in rainwater to form acid rain and is directly fixed in the ocean, which results in ocean acidification. However, in the present invention, atmospheric carbon dioxide reacts with the aqueous solution to form an aqueous solution of calcium bicarbonate, which is then supplied to the ocean. Therefore, ocean acidification is not caused, and atmospheric carbon dioxide can be captured and fixed in the ocean while preventing ocean acidification.

[0025] 1 is a block diagram showing an outline of the overall configuration of a calcium ion supplying device according to the present invention; 2 is a block diagram showing an outline of the overall configuration of a calcium ion supplying device according to the present invention; 3 is a block diagram showing an outline of the overall configuration of a calcium ion supplying device according to the present invention; 4 is a block diagram showing another embodiment of a reaction tank of a calcium ion supplying device according to the present invention;

[0026] 1 and 2 show an outline of the overall configuration of a calcium ion supplying device 1 used to carry out the marine environment improvement method according to the present invention.

[0027] That is, in the method for improving the marine environment of the present invention, as shown in FIG. 1, limewater L is supplied to a reaction tank 10, and air A is supplied to the limewater L in the reaction tank 10, and carbon dioxide CO ２ and the lime water L, and the resulting calcium bicarbonate Ca(HCO ３ ) ２ The aqueous solution is supplied to the sea S.

[0028] This marine environment improvement method can be carried out by a calcium ion supply device 1 including a reaction tank 10, a supply device 2, a gas-liquid contactor 3, a transport device 4, a control device 5, and a solar power generation device 6, as shown in Figures 1 and 2.

[0029] The reaction tank 10 is configured as a water tank that can be filled with limewater L. This reaction tank 10 is configured as an open-type water tank with an open top so that the limewater L in the reaction tank 10 can be brought into contact with the atmosphere A and the atmosphere A can be exhausted after contact. This may be a case where the top of the reaction tank 10 is simply open, or the top of the reaction tank 10 is sealed with a lid (not shown) having an exhaust path and is open to the atmosphere via this exhaust path. However, an open-type water tank with an open entire top is preferable because it increases the opportunity for direct contact between the limewater L in the reaction tank 10 and the atmosphere A. Furthermore, in order to increase the opportunity for direct contact between the limewater L and the atmosphere A, the reaction tank 10 is preferably shaped to have a large plane area and a shallow depth.

[0030] A supply line 21 of a supply device 2 is connected to the reaction tank 10 for supplying lime water L into the reaction tank 10. The supply device 2 is configured to include the supply line 21, the supply pump 22, and the preparation tank 23 so that lime water L prepared in a preparation tank 23 is supplied to the reaction tank 10 from the supply line 21 via a supply pump 22. To prepare lime water L in the preparation tank 23, water and calcium hydroxide Ca(OH) soluble in the amount of water are introduced into the preparation tank 23. ２ Add and stir to dissolve, and each time add water and calcium hydroxide Ca(OH) ２ Alternatively, a large amount of calcium hydroxide Ca(OH) may be added to the preparation tank 23 to prepare lime water L. ２ The lime water L may be prepared by adding an appropriate amount of water to the mixture, stirring the mixture, leaving it to stand, and then removing the supernatant lime water L. Subsequently, water may be added and the preparation of lime water L may be repeated in the same manner. The stirring may be performed by rotating the stirring blades 25 with a motor 24, by rotating a stirring bar (not shown) with magnetic force, or by using a water flow pump (not shown). The water used to prepare the lime water L may be rainwater, reservoir water, river water, groundwater, tap water, industrial wastewater, treated sewage, or the like. The preparation device 2 may be provided with a heat pump, Peltier element, or other water temperature control device C to obtain lime water L at a desired temperature depending on the environment. In particular, the lower the temperature of the lime water L, the greater the amount of calcium hydroxide (Ca(OH)) in the water. ２ The solubility of calcium hydroxide Ca(OH) increases (0.153 g / 100 ml water at 30°C, 0.176 g / 100 ml water at 10°C, and 0.185 g / 100 ml water at 0°C), so dissolving the calcium hydroxide in water while cooling it with the water temperature control device C makes preparation easier. Therefore, 1 mole of calcium hydroxide Ca(OH) ２ When dissolving in water to make lime water L, 40 to 50 liters of water is required, assuming complete dissolution. If you use 50 to 60 liters of water, 1 mole of calcium hydroxide (Ca(OH)) will be 74 g. ２The amount of water used is 50 to 60 liters, but this is an example of the amount of water used to dissolve the calcium hydroxide, and it may be dissolved in a larger amount of water, or in an amount that completely dissolves the calcium hydroxide. ２ In this case, an appropriate amount of water is added, stirred, and the supernatant lime water L is taken out after leaving it to stand. In this case, 1 mole of calcium hydroxide Ca(OH) is 74 g in 40 to 50 liters, which is close to the theoretical value. ２ It is possible to prepare lime water L in which calcium hydroxide (Ca(OH)) is dissolved. It is not necessary to prepare lime water L with saturated solubility. Although it is acceptable to have a margin in solubility, as this will prevent precipitation when the temperature changes, it is not good to have too much margin. In addition, in the above example, 1 mole (74 g) of calcium hydroxide (Ca(OH)) is used. ２ However, the scale of the supply device 2 is not particularly limited, and may be, for example, 1000 times the amount, 50 to 60 tons, or 10000 times the amount, 500 to 600 tons. This can be determined depending on the amount of water to be procured, such as rainwater, reservoir water, river water, groundwater, tap water, industrial wastewater, or treated sewage.

[0031] The gas-liquid contactor 3 is composed of a pump 31 for collecting atmospheric air A, a pressure-transfer path 32 extending from the atmosphere to the bottom of the reaction tank 10 to pump the atmospheric air A into the reaction tank 10 using the pump 31, and a bubbling head 33 provided at the bottom of the reaction tank 10, which is the extended tip of the pressure-transfer path 32. The gas-liquid contactor 3 is configured to exhaust atmospheric air A from the bubbling head 33 to the limewater L supplied to the reaction tank 10. The bubbling head 33 is provided at the bottom of the reaction tank 10 so that the atmospheric air A exhausted into the reaction tank 10 can be sufficiently contacted with the limewater L in the reaction tank 10. Furthermore, the bubbling head 33 may be formed to extend over the entire bottom surface of the reaction tank 10 and have many pores formed therein to generate as fine bubbles as possible, so that the atmospheric air A exhausted from the bubbling head 33 can be contacted as efficiently as possible with the limewater L in the reaction tank 10. Specifically, an air stone, a nanobubble head, or the like can be used. However, if the pores are made too small, the load on the pump 31 that pumps the atmosphere A increases, reducing the absolute amount of atmosphere A supplied to the reaction vessel 10. Therefore, it is possible to give priority to the supply of atmosphere A and adopt a bubbling head 33 with a large pore size that can supply as much atmosphere A as possible. In this case, the size of the bubbles increases, and the bubbles rise quickly and are released into the atmosphere A again before they are fully in contact with the limewater L in the reaction vessel 10. However, since the absolute amount of atmosphere A that can come into contact with the limewater L increases, the carbon dioxide CO ２ This is good in the sense that it reacts with lime water L.

[0032] Furthermore, when the absolute amount of air A supplied by the pump 33 is increased in this way, an obstacle wall 11 may be provided in the reaction tank 10 as shown in FIG. 3( a) so that the air bubbles are in contact with the limewater L in the reaction tank 10 for as long as possible, or an agitator 12 for agitating the air bubbles may be provided in the reaction tank 10 as shown in FIG. 3( b). In this case, the obstacle wall 11 may be a plurality of plate pieces or mesh plates made of the same material as the reaction tank 10, which are provided so as to block the rising of the bubbles, or may be provided by forming a spiral flow path. Furthermore, as shown in FIG. 3( c), an obstacle wall 11 may be provided by forming a wall made of calcium carbonate (CaCO ), such as a shell, to block the rising of the bubbles. ３Alternatively, the agitator 12 may be configured to use a medium such as a suction pump 12a or a pump 12b, and use this filler 13 instead of the obstacle wall 11. The agitator 12 may be configured to use a motor 12a to drive an agitator blade 12b, a magnetic agitator (not shown), or a water current. Alternatively, as shown in FIG. 3(d), the agitator 12 may be configured to rotate between the limewater L and the atmosphere A, generating bubbles of the atmosphere A in the limewater L and splashes of the limewater L into the atmosphere A, thereby bringing the limewater L into contact with the atmosphere A, like the aquaculture agitator blade 14, or a spray-type agitator in which the limewater L itself is sprayed from the reaction tank 10 into the atmosphere A and then received back in the reaction tank 10, and this process is repeated to bring the limewater L into contact with the atmosphere A.

[0033] However, in the case of the gas-liquid contactor 3 that pumps in air A with the pump 33, new air A is continuously sent, but in the case of the sparging type, the air A in the place must be renewed, otherwise carbon dioxide CO ２ Therefore, it is necessary to either close the sprayed space and continue to send in fresh air A using a blower or to spray in a well-ventilated space. In any case, it is necessary to avoid a configuration in which the sprayed limewater L is blown away by the air A and cannot be collected in the reaction tank 10, so the droplets to be sprayed are determined depending on the environment. In particular, limewater L contains carbon dioxide CO ２ By absorbing calcium carbonate CaCO ３ The solution changes to a cloudy white solution in which calcium bicarbonate Ca(HCO ３ ) ２ In the case of spray type, if used for a long period of time, calcium carbonate (CaCO ３ There is a concern that the droplets may aggregate and cause clogging, so mist-like droplets are effective in that they come into contact with the atmosphere A, but when considering the operation of the device, droplets that are on the border between flowing water like that flowing in a chiller device and droplets are preferable.

[0034] The size of the reaction tank 10 is set so as to maximize the contact area with the atmosphere A. For example, when the supply amount of limewater L supplied from the supply device 2 is 50 to 60 tons, the reaction tank 10 is preferably formed to have an effective water storage capacity of 50 to 60 tons, with dimensions of, for example, 10 m wide x 10 m long x 0.5 to 0.6 m deep. When the supply amount of limewater L supplied from the supply device 2 is 500 to 600 tons, the reaction tank 10 is preferably formed to have an effective water storage capacity of 500 to 600 tons, with dimensions of, for example, 20 m wide x 25 to 30 m long x 1 m deep. However, the size of the reaction tank 10 is not limited to the above, and is determined depending on the supply amount of limewater L supplied from the supply device 2, the target treatment time, and the treatment capacity of the gas-liquid contactor 3. Carbon dioxide CO ２ The concentration of ３ 743 mg / m at 30°C ３ Therefore, 10,000 liters of air A contains approximately 7.5 g of carbon dioxide CO ２ Therefore, 1 mole of carbon dioxide CO ２ In order to supply 1 mole of carbon dioxide CO, approximately 58,700 liters of air A are required. When a pump 33 with an output of 1,000 liters / minute is used, 1 mole of carbon dioxide CO is supplied in approximately 1 hour. ２ Of course, this is a general description of the atmosphere A, and the carbon dioxide CO ２ In areas or places where the concentration of is high, the amount of atmospheric A required is less.

[0035] When the limewater L in the reaction vessel 10 is brought into contact with the atmosphere A, the limewater L and the carbon dioxide CO in the atmosphere A are mixed. ２ reacts to form lime water L, which becomes calcium carbonate CaCO ３ and water, which is further decomposed into carbon dioxide CO ２ If calcium bicarbonate (Ca(HCO ３ ) ２In this case, even if the limewater L supplied from the supply device 2 is sufficiently cooled by the supply device 2, there is a concern that the temperature may gradually rise if the temperature of the air A supplied from the gas-liquid contactor 3 is high or due to the heat of the pump 33 of the gas-liquid contactor 3. Therefore, the reaction tank 10 is provided with a water temperature control device C such as a heat pump, a Peltier element, or other devices, similar to the tank 23 of the supply device 2, to keep the temperature of calcium bicarbonate Ca(HCO ３ ) ２ The calcium bicarbonate Ca(HCO ３ ) ２ The aqueous solution of calcium bicarbonate Ca(HCO ３ ) ２ In the process of forming an aqueous solution of ２ can be recovered.

[0036] Therefore, 1 mole of calcium hydroxide (Ca(OH)) is 74 g. ２ For example, 1 mole (44 g) of carbon dioxide CO ２ The volume of air A, which contains about 58,700 liters of carbon dioxide, is doubled to 2 moles (88 g). ２ By supplying about 117,400 liters of air A containing ３ ) ２ 50-60 liters of calcium bicarbonate Ca(HCO ３ ) ２ can be obtained from the atmosphere A, and 2 moles (88 g) of carbon dioxide CO ２ For example, when operating one cycle per day, 1 mole of calcium hydroxide (Ca(OH)) (74 g) can be recovered. ２ For example, from 50 to 60 liters of lime water L, 1 mole of about 162 g of calcium bicarbonate Ca(HCO ３ ) ２ 50-60 liters of calcium bicarbonate Ca(HCO ３ ) ２ To obtain an aqueous solution of 2 moles (88 g) of carbon dioxide CO２ Therefore, even if the atmosphere A is supplied from the gas-liquid contactor 3 for 10 hours, this can be achieved by using a pump 31 with a capacity of 196 liters / minute. ２ It is possible that calcium hydroxide Ca(OH) is not included, but in that case, the capacity of the pump 31 can be increased or the treatment time can be extended. ２ When 50 to 60 liters of limewater L having dissolved therein is to be treated in a reaction tank 11 having a capacity of 50 to 60 tons, which is 1,000 times larger, or a reaction tank 11 having a capacity of 500 to 600 tons, which is 10,000 times larger, similarly, the capacity of the pump 31 can be increased or the treatment time can be extended. The capacity of the pump 31 may be increased by increasing the capacity of the pump 31 itself, or by increasing the number of pumps. In either case, the power consumption of the pump 31 itself is small, so this can be easily accommodated.

[0037] The transport device 4 has a transport path 41 connected to the reaction tank 10, and the transport path 41 transports calcium bicarbonate Ca(HCO ３ ) ２ The water is supplied to the sea S by driving a transport pump 42 provided in the transport path 41. ３ ) ２ The outlet 43 for discharging the aqueous solution of calcium bicarbonate Ca(HCO ３ ) ２ As long as the aqueous solution can be supplied to the sea S, the location where the device is installed is not particularly limited.

[0038] Calcium bicarbonate Ca(HCO ３ ) ２ By supplying the aqueous solution of calcium bicarbonate Ca(HCO ３ ) ２This aqueous solution can supply approximately 40 g of calcium ions per mole and 122 g of bicarbonate ions per 2 moles to the sea S. Therefore, in a single treatment, for example, when 50 to 60 tons, which is 1000 times the original volume, is treated, 40 kg of calcium ions and 122 kg of bicarbonate ions can be supplied to the sea S, and when 500 to 600 tons, which is 10,000 times the original volume, is treated, 400 kg of calcium ions and 1,220 kg of bicarbonate ions can be supplied to the sea S.

[0039] Here, the sea S does not simply refer to seawater, but also includes sandy areas that the seawater extends over. For example, the outlet 43 may be located at a depth of less than 50 meters where shallow groundwater joins, e.g., 20 to 30 meters, or at a depth of 50 meters or more where deep groundwater joins, e.g., 50 to 60 meters, or in the deep sea at a depth of 200 meters or more, or at a depth of less than 10 meters. Furthermore, the outlet 43 is not limited to being located in the sea, but may also be located on sandy areas of the same depth. It may also be located on sandy areas in the intertidal zone between the high tide shoreline and the low tide shoreline, or on sandy areas in the shallow layer at a depth of less than 50 meters, deep layers at a depth of 50 meters or more, or deep sea layers at a depth of 200 meters or more. In particular, when considering supplying calcium ions to marine exoskeletal organisms, it is preferable to supply them to the intertidal zone or shallow water, particularly to sandy areas less than 10 m deep where shellfish are likely to live, and more preferably less than 5 m deep. On the other hand, such intertidal zones and shallow waters, especially the morning zone, are susceptible to high and low water temperatures and are easily affected by air temperature, and depending on the location and season, calcium ions are likely to remineralize, and the calcium that has been ionized with great care is remineralized and fixed, so it is preferable to supply them taking into consideration that they will be easily absorbed as calcium ions by marine exoskeletal organisms. In other words, calcium bicarbonate Ca(HCO ３ ) ２When preparing the aqueous solution of the above, the reaction tank 11 may be heated or cooled by a water temperature control device C to adjust the temperature. When considering the growth of marine exoskeleton organisms such as shellfish, these shellfish feed on phytoplankton, and since phytoplankton grows by photosynthesis, it is found in large quantities at depths where light reaches. Therefore, calcium bicarbonate Ca(HCO ３ ) ２ It is also preferable that the outlet 43 for the aqueous solution of the abovementioned phytoplankton be supplied to a place where a large amount of phytoplankton is present. From this perspective, it is preferable to supply the solution to the intertidal zone or shallow layer, particularly to a sandy area less than 10 m deep where shellfish are likely to live, more preferably less than 5 m deep. However, calcium bicarbonate Ca(HCO ３ ) ２ When supplying the aqueous solution of the above, if the water pressure from the outlet 43 is high, there is a concern that the sandy soil may be dug up, so it is preferable to supply the water at a reduced water pressure, to supply the water by branching the outlet 43 into multiple outlets and reducing the water pressure, or to supply the water by merging it with an existing underground water vein flowing into the sea S.

[0040] The control device 5 is configured to control the overall operation of the calcium ion supply device 1. Specifically, it is configured to control a series of operations by at least the supply device 2, the gas-liquid contact device 3, and the transport device 4. The supply of power generated by the solar power generation device 6 to the supply device 2, the gas-liquid contact device 3, and the transport device 4 is also controlled by the control device 5. Although the control device 5 may control everything, this does not exclude other cases. Part of the control by the control device 5 may be manually operated artificially, or all of the control may be manually operated.

[0041] To explain the series of operations, first, the supply device 2 supplies water and calcium hydroxide to the preparation tank 23. At this time, when a pump (not shown) is used to supply water, the operation of this pump may be controlled by the control device 5, or the control device 5 may control the pump to stop operation when the tank is full of water. If water pressure can be used, the control device 5 may control the opening and closing of a valve (not shown) to supply water. Of course, this may be done manually, without using the control device 5.

[0042] Next, the water in the preparation tank 23 is stirred. The driving of the motor 24 that performs this stirring can also be controlled by the control device 5. By stirring, calcium hydroxide Ca(OH) ２ The calcium hydroxide Ca(OH) is dissolved in the lime water L, and the lime water L is transferred from the supply line 21 to the reaction tank 10 via the supply pump 22. At this time, the operation of the supply pump 22 may be controlled by the control device 5. ２ The amount of calcium hydroxide Ca(OH) may be automatically added by the control device 5 in accordance with the amount of water supplied to the preparation tank 23, or a large amount of calcium hydroxide Ca(OH) ２ is charged into the preparation tank 23, and after stirring, the dispersed excess calcium hydroxide Ca(OH) ２ After the limewater L settles, the limewater L may be transferred to the reaction tank 10. However, if a large amount of calcium hydroxide Ca(OH) ２ When adding, after each stirring, the dispersed excess calcium hydroxide Ca(OH) ２ Since we must wait for the time for the precipitated calcium hydroxide Ca(OH) ２ In order to prevent the transfer of excess calcium hydroxide Ca(OH), a strainer or the like may be used to transfer only the supernatant limewater L. ２ To prevent the dispersion of calcium hydroxide Ca(OH) ２ is placed in a nonwoven bag or the like, and calcium hydroxide Ca(OH) is poured through the bag. ２ Dissolve calcium hydroxide Ca(OH) in an amount greater than the amount dissolved. ２However, it is also possible to prevent calcium hydroxide Ca(OH) from dispersing in the reaction vessel 10. In this case, calcium hydroxide Ca(OH) dispersed in excess in the lime water L may be ２ It is possible to prevent the excess calcium hydroxide Ca(OH) from being transferred to the reaction tank 10, and to prevent the excess calcium hydroxide Ca(OH) from being transferred to the reaction tank 10. ２ The limewater L can be transferred to the reaction tank 10 without waiting for the limewater to settle.

[0043] When the supply of limewater L to the reaction vessel 10 is completed, the supply pump 22 is stopped, and the pump 31 of the gas-liquid contactor 3 is operated to perform bubbling. At this time, the operation of the pump 31 may be controlled by the control device 5. When the limewater L is bubbling, cloudy calcium carbonate CaCO ３ Then, a clear aqueous solution of calcium bicarbonate Ca(HCO ３ ) ２ Since the solution is calcium bicarbonate Ca(HCO ３ ) ２ When the aqueous solution of calcium bicarbonate Ca(HCO ３ ) ２ The determination of whether the aqueous solution of calcium carbonate (CaCO3) has been obtained may be made simply by checking the bubbling time, or by checking whether the aqueous solution of calcium carbonate (CaCO3) has been obtained from lime water (L). ３ It becomes cloudy when it changes into an aqueous solution of calcium bicarbonate Ca(HCO ３ ) ２ The lime water L becomes transparent again when it becomes an aqueous solution of calcium bicarbonate (CaHCO ), so this color change can be detected by a sensor, or the pH change can be detected by a pH meter. Because lime water L is a strong alkali, it initially shows a high pH value, but eventually becomes calcium bicarbonate (CaHCO ). ３ ) ２ Even if the solution is converted into an aqueous solution of carbon dioxide CO ２ If we continue to supply carbon dioxide, the water solvent will react with carbon dioxide. ２ is dissolved and the pH changes to the acidic side, so by capturing this pH change, calcium bicarbonate Ca (HCO ３ ) ２It may be determined that the aqueous solution has become

[0044] Then, calcium bicarbonate Ca(HCO ３ ) ２ The aqueous solution is transported to the sea S by the transport device 4 and supplied to the sea. At this time, the operation of the transport pump 42 is controlled by the control device 5.

[0045] Thereafter, the above process is repeated by batch processing.

[0046] The solar power generation device 6 is charged with all driving energy when the control device 5 controls a series of operations of the calcium ion supply device 1. In this case, the solar power generation device 6 may operate the calcium ion supply device 1 while supplying generated power to the calcium ion supply device 1, or may charge the battery 61 and then operate the calcium ion supply device 1 with the charged power. In addition, although the present embodiment uses the solar power generation device 6, it may also use renewable energy such as wind power generation, geothermal power generation, or power generation using biomass gas. It may also use electricity generated by fossil fuels, or it may use such electricity in combination with renewable energy.

[0047] The calcium ion supply device 1 of the present invention is, for example, a calcium hydroxide (Ca(OH)) having 1 mole of about 74 g. ２ When treating 50 to 60 liters of limewater L containing dissolved carbon dioxide, 2 moles (approximately 88 g) of CO ２ and 50 to 60 liters of calcium bicarbonate Ca(HCO ３ ) ２ Therefore, for example, if 50 to 60 tons, which is 1000 times the amount, is treated in one treatment, 40 kg of calcium ions can be supplied to the sea S, and 88 kg of carbon dioxide CO ２When processing 10,000 times as much as 500 to 600 tons, 400 kg of calcium ions can be supplied to the sea S, and 880 kg of carbon dioxide CO ２ In the case of solar power generation, 17 to 48 grams of carbon dioxide CO can be recovered per kilowatt. ２ In the case of electricity generated using fossil fuels, it is estimated that it emits 690g of carbon dioxide CO per kilowatt. ２ Therefore, when processing 50 to 60 tons, 88 kg of carbon dioxide CO ２ That is, 5176.47 to 1833.33 kilowatts can be used for solar power generation, and 12.75 kilowatts can be used for electricity using fossil fuels, and when processing 500 to 600 tons, 880 kg of carbon dioxide CO ２ That is, 51,764.7 to 18,333.3 kilowatts can be used for solar power generation, and 127.5 kilowatts can be used for electricity using fossil fuels. If the power consumption for one process can be reduced below these figures, the amount of carbon dioxide CO emissions reduced will be reduced by the same amount. ２ Therefore, the calcium ion supply device 1 not only supplies calcium ions to the sea S but also recovers carbon dioxide CO ２ If we want to actively recover this waste, we can use renewable energy sources such as solar power.

[0048] In this embodiment, the reaction tank 10 is supplied with limewater L prepared by the supply device 2, but the supply device 2 may be omitted and water may be supplied to the reaction tank 10. In this case, calcium carbonate CaCO ３ As a result, the water and calcium carbonate CaCO ３ is the atmospheric carbon dioxide CO supplied by the gas-liquid contactor 3. ２ It reacts with calcium bicarbonate Ca (HCO ３ ) ２In this case, the lime water L supply device 2 is not required, so the configuration and control can be simplified. However, the lime water L is converted into calcium carbonate CaCO ３ After it becomes a cloudy liquid with water, calcium bicarbonate Ca (HCO ３ ) ２ When calcium carbonate CaCO ３ is cloudy at the molecular level, so it is carbon dioxide CO ２ It reacts with calcium bicarbonate Ca(HCO ３ ) ２ However, water and calcium carbonate (CaCO ３ From calcium bicarbonate Ca (HCO ３ ) ２ When calcium carbonate CaCO is obtained, ３ It itself is insoluble in water, so carbon dioxide CO ２ dissolves to form carbonated water, and the carbonated water becomes calcium carbonate CaCO ３ Dissolve calcium bicarbonate Ca(HCO ３ ) ２ This means that efficiency will decrease, so it is important to take this into consideration.

[0049] As described above, according to the marine environment improvement method of the present invention, the calcium ion supply device 1 supplies carbon dioxide CO ２ While recovering calcium bicarbonate Ca(HCO ３ ) ２ The resulting aqueous solution of calcium bicarbonate Ca(HCO ３ ) ２ By supplying the aqueous solution of the above to the sea S, calcium ions can be supplied to the sea S. Therefore, these calcium ions can be used to support the growth of marine organisms, especially marine exoskeleton organisms. In other words, the sea S can absorb carbon dioxide CO2 that has already been released and diffused into the atmosphere A. ２ When absorbing carbon dioxide CO ２is dissolved in rainwater and falls into the sea S and is absorbed. In this case, a large amount of hydrogen ions is generated, which leads to the acidification of the sea S, which has already caused problems such as inhibiting the formation of exoskeletons in marine exoskeleton organisms. However, when the calcium ion supply device 1 is used, the carbon dioxide CO in the atmosphere A recovered by this calcium ion supply device 1 ２ is calcium bicarbonate Ca (HCO ３ ) ２ is supplied to the sea S as an aqueous solution, and the resulting solution becomes calcium ions and bicarbonate ions, and hydrogen ions are not generated, preventing the acidification of the sea S. Furthermore, calcium ions necessary for the formation of exoskeletons of marine exoskeleton organisms can be supplied.

[0050] In addition, the lime water supply device 2 is eliminated, and calcium carbonate CaCO ３ Water is supplied to the reaction tank 10 containing calcium bicarbonate Ca(HCO ３ ) ２ When preparing an aqueous solution of calcium carbonate CaCO ３ This allows the use of shells that are generated as waste after aquaculture or consumption, thereby reducing waste.

[0051] In this embodiment, calcium hydroxide Ca(OH) ２ and calcium carbonate CaCO ３ uses renewable energy to heat shells and limestone in a sealed furnace, eliminating the carbon dioxide (CO) that is generated during heating. ２ The calcium oxide (CaO) was recovered and digested to obtain calcium hydroxide (Ca(OH) ２ Alternatively, the calcium hydroxide thus obtained may be Ca(OH) ２ atmospheric carbon dioxide CO ２ Calcium carbonate CaCO obtained by absorbing ３ may be.

[0052] In this way, carbon dioxide CO ２ By collecting CO2, the carbon dioxide fixed in these shells and limestone can be ２The calcium oxide (CaO) is extracted as calcium hydroxide (Ca(OH) ２ is the carbon dioxide CO in the atmosphere A ２ It absorbs calcium carbonate CaCO ３ and carbon dioxide CO ２ absorbs calcium bicarbonate Ca (HCO ３ ) ２ This is then supplied to the ocean S, so the carbon dioxide CO recovered from shells and limestone ２ Industrial carbon dioxide CO ２ If it can be used for another purpose, 1 mol of calcium carbonate CaCO ３ to 1 mole of carbon dioxide CO ２ and 2 moles of carbon dioxide CO ２ is recovered to obtain calcium bicarbonate Ca(HCO ３ ) ２ By supplying it to the sea S as 1 mole of calcium carbonate CaCO ３ to 3 moles of carbon dioxide CO ２ Of these, 1 mole of carbon dioxide CO ２ is the carbon dioxide CO contained in the original shells and limestone. ２ So, the result is 1 mole of calcium carbonate CaCO ３ From the raw material, 2 moles of carbon dioxide CO ２ This will also enable the creation of a recycling-oriented society in which the large amount of seashells generated as industrial waste is converted into calcium ions and returned to the sea. ２ This industrial carbon dioxide CO ２ was produced during oil refining, but due to the global trend of reducing carbon dioxide emissions, oil refineries are being closed, and there is a shortage of carbon dioxide. ２ The amount of industrial carbon dioxide (CO2) used in industry is increasing. ２ Even in such a situation, if the calcium ion supply device 1 of the present invention is used, calcium ions can be supplied to the sea S while carbon dioxide CO in the atmosphere A is ２and industrial carbon dioxide CO ２ can be obtained.

[0053] In addition, calcium bicarbonate Ca (HCO ３ ) ２ is a liquid that dissolves in water and decomposes into calcium ions and bicarbonate ions, but calcium carbonate (CaCO ３ Even if the amount of carbon dioxide in the atmosphere A is consumed, if the atmosphere A is still supplied to the reaction vessel 10 and bubbling by the gas-liquid contactor 3 is continued, the amount of carbon dioxide in the atmosphere A will increase. ２ However, calcium carbonate dissolves in the water solvent to become carbonated water, which becomes acidic, and if this is supplied to the sea S, it will contribute to ocean acidification. ３ is calcium bicarbonate Ca (HCO ３ ) ２ Even after the ２ is supplied to the solvent water, and carbon dioxide CO ２ In order to prevent the reaction vessel 10 from dissolving and becoming acidic, excess calcium carbonate (CaCO ３ It is preferable to keep adding water continuously.

[0054] The calcium ion supply device 1 of the present invention is a device for supplying calcium bicarbonate (Ca(HCO ３ ) ２ In parallel with or separately from the aqueous solution of the above, lime water L prepared by the supply device 2 may be supplied to the sea S. In this case, the lime water L can supply calcium ions to the sea S simply by supplying it to the sea S as it is, and since it is a strong alkali, it can also supply carbon dioxide CO ２ This means that ocean acidification caused by carbon dioxide CO ２ The rainwater that has dissolved CO has been pouring down, making the water acidic and increasing the hydrogen ion concentration. ２ +H ２ O → To the sea → HCO ３ － +H ＋

[0055] Therefore, when lime water L is supplied to sea S, two hydroxy ions are generated per mole of lime water L. Ca(OH) ２ aq → To the sea → Ca ＋ +2OH －

[0056] And 1 mole of lime water L contains 2 moles of carbon dioxide CO ２ When the seawater is acidified, two hydrogen ions are generated, which act as a buffer and prevent the acidification of seawater. ３ － +2H ＋ + Ca ＋ +2OH － → Ca ＋ + 2HCO ３ － +2H ２ O

[0057] In other words, 2 moles of carbon dioxide CO ２ By absorbing calcium bicarbonate Ca (HCO ３ ) ２ When lime water L is supplied to sea S in the same manner as when the aqueous solution of ２ dissolves and acts as a buffer with the hydrogen ions oxidized, so 2 moles of carbon dioxide CO ２ The same effect can be obtained as if the

[0058] Calcium bicarbonate Ca(HCO ３ ) ２ and lime water L from the supply device 2 are mixed to form calcium bicarbonate Ca(HCO ３ ) ２ Only the aqueous solution of calcium carbonate (HCO 3 ) or lime water (L) alone can be used, or both can be used. In the case of both, the ratio of each can be changed. ３ ) ２ and carbon dioxide CO ２ In particular, the amount of carbon dioxide CO dissolved in the sea S can be adjusted by supplying lime water L to the sea bottom where the temperature is low and acidification is likely to occur.２ is higher in high latitude regions near the Arctic and Antarctic where the water temperature is low, especially in the Northern Hemisphere where economic activity is active. Therefore, in these high latitude regions and the Northern Hemisphere, it is very effective to supply limewater L. Therefore, in order to increase the proportion of limewater L in these regions, calcium bicarbonate Ca (HCO ３ ) ２ The ratio of the aqueous solution of the present invention to the lime water L may be changed.

[0059] It should be noted that the present invention can be embodied in various other forms without departing from its spirit or essential features. Therefore, the above-described embodiments are merely illustrative in all respects and should not be interpreted as limiting. The scope of the present invention is defined by the claims and is not limited in any way by the text of the specification. Furthermore, all modifications and variations that fall within the scope of the claims are within the scope of the present invention.

[0060] REFERENCE SIGNS LIST 1 calcium ion supply device 10 reaction tank 2 supply device 3 gas-liquid contact device 31 pump 4 conveying device 41 conveying path 42 conveying pump 5 control device 6 solar power generation device (renewable energy supply device) A atmosphere C water temperature control device L lime water S sea

Claims

1. A method for improving the marine environment, comprising supplying lime water or calcium carbonate and water to a reaction tank, supplying atmospheric air into the reaction tank, causing carbon dioxide in the air to react with the lime water or calcium carbonate and water in the reaction tank, and supplying the resulting aqueous solution of calcium bicarbonate to the sea.

2. A method for improving the marine environment according to claim 1, wherein carbon dioxide in the atmosphere is reacted with lime water or calcium carbonate and water in the reaction tank while the reaction tank is cooled.

3. The method for improving the marine environment according to claim 1, wherein the lime water is prepared by adding water to calcium oxide obtained by recovering carbon dioxide by burning calcium carbonate in a closed system using renewable energy, or by adding water to calcium hydroxide obtained by slaked calcium oxide.

4. The method for improving the marine environment according to claim 1, wherein the calcium carbonate is obtained by burning calcium carbonate in a closed system using renewable energy to recover carbon dioxide, and then allowing the calcium oxide obtained to absorb carbon dioxide from the atmosphere, or by digesting the calcium oxide to obtain calcium hydroxide, and then allowing carbon dioxide from the atmosphere to absorb carbon dioxide.

5. A method for improving the marine environment, characterized by using renewable energy to calcine calcium carbonate in a closed system, recovering carbon dioxide, and then adding water to the calcium oxide obtained to prepare limewater, or by adding water to calcium hydroxide obtained by slaked the calcium oxide, and supplying the resulting limewater to the sea.

6. A method for improving the marine environment according to claim 1 or 2, wherein each step is carried out using renewable energy.

7. A method for improving the marine environment according to any one of claims 1 to 5, wherein the calcium carbonate is obtained from seashells.

8. A method for improving the marine environment according to any one of claims 1 to 5, wherein limestone is used as calcium carbonate.

9. A method for improving the marine environment according to any one of claims 1 to 5, wherein the water used to prepare the lime water is either groundwater, stored water, rainwater, river water, or industrial wastewater.

10. The method for improving the marine environment according to claim 1, wherein the obtained aqueous solution of calcium bicarbonate is supplied to sandy areas in the sea.

11. The method for improving the marine environment according to claim 5, wherein the obtained lime water is supplied to sandy areas in the sea.

12. The method for improving the marine environment according to claim 5, wherein the obtained lime water is supplied to the seabed.

13. A calcium ion supply system comprising: a reaction tank that can be filled with lime water or calcium carbonate and water; a supply device that supplies lime water or water to the reaction tank; a gas-liquid contactor that has a pump that collects atmospheric air and brings the atmospheric air into contact with the lime water or calcium carbonate and water filled in the reaction tank; a transport device that transports an aqueous solution of calcium bicarbonate produced by the reaction of carbon dioxide in the air with the lime water or calcium carbonate and water from the reaction tank to the outside using a transport pump, and transports the aqueous solution of calcium bicarbonate to the sea via a transport path connected to the transport pump; and a control device that controls each of these devices.

14. The calcium ion supplying device according to claim 13, further comprising a water temperature control device for controlling the temperature of the aqueous solution in the reaction tank.

15. A calcium ion supplying device according to claim 13 or 14, further comprising a renewable energy supplying device that produces renewable energy and supplies the renewable energy to the device.

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