Device and method for carbon dioxide capture and ocean carbon sequestration

Abstract

The present invention relates to the technical field of marine carbon fixation and storage, and in particular to a device and method for carbon dioxide capture and marine carbon sequestration. The device includes a seawater alkalization mechanism, a diatom breeding system, a power component and a monitoring component, the power component is respectively connected to the seawater alkalization mechanism, the diatom breeding system and the monitoring component, the water outlet of the seawater alkalization mechanism is connected to the diatom breeding system, and the monitoring component is respectively connected to the seawater alkalization mechanism and the diatom breeding system. It realizes the integrated process of seawater alkalization and seaweed cultivation, quickly captures atmospheric carbon dioxide by dissolving alkaline minerals in seawater, uses diatom breeding to reduce the concentration of free silicate and carbonic acid in seawater, stores carbon in inorganic / organic, granular / dissolved forms, and increases the marine carbon storage period.

Description

Technical Field

[0001] The present invention relates to the technical field of ocean carbon fixation and storage, and in particular to a device and method for carbon dioxide capture and ocean carbon storage. Background Art

[0002] The continuous increase in anthropogenic carbon dioxide emissions has led to global warming, causing a series of negative environmental effects such as frequent extreme weather, rising sea levels, and water hypoxia and acidification, threatening the sustainable development of human society. However, in the foreseeable future, fossil fuels will still be the main energy source of industrial society. It is urgent to develop carbon dioxide capture and storage technology and break through the bottleneck of industrial application. The ocean is the largest active carbon reservoir on the surface. It has played a role in regulating climate change in the history of the earth and has great potential for increasing carbon sinks. Marine carbon sequestration and storage technology that increases marine carbon sinks through artificial measures can achieve artificial regulation of the global carbon cycle and solve the problem of global warming from the root. At the same time, based on the principle of cyclic coupling of biogenic elements such as carbon, nitrogen, phosphorus, and silicon in the marine system, artificial regulation of key biogenic elements such as nitrogen and phosphorus can be achieved through regulation of the global carbon cycle.

[0003] The carbon sink mechanism of the marine system includes solubility pump, biological carbon pump, carbonate pump and microbial carbon pump. The solubility pump refers to the process in which more carbon dioxide dissolves in seawater when the atmospheric carbon dioxide partial pressure is higher than that of the ocean, until the pressure at the air-sea interface reaches equilibrium. It is a passive physical and chemical process. The biological carbon pump is activated in the euphotic layer of the ocean, where phytoplankton converts dissolved inorganic carbon into organic carbon through photosynthesis, and transforms it into debris such as biological remains or feces through the migration of the food web. It migrates into the deep sea or is buried on the seabed under gravity to achieve long-term carbon storage. The carbonate pump refers to the process in which calcified organisms such as coccolithophores or shellfish fix carbonates in seawater to form a protective shell of calcium carbonate, and finally settle and bury calcium carbonate particles on the seabed. In the process of calcium carbonate formation, 1 mol of carbon dioxide is released into the atmosphere for every 1 mol of calcium carbonate formed, so the carbonate pump is also called the carbonate reverse pump. The microbial carbon pump is a process in which dissolved organic carbon is converted from active to inert through the metabolic activities of microorganisms. Inert dissolved organic carbon is not easily degraded and can be preserved in the ocean for thousands of years. Marine carbon sequestration and storage technology is a technical system that accelerates the above-mentioned marine carbon pump through human intervention measures. There are currently a variety of technical approaches, among which the theories of seawater alkalization and seaweed aquaculture are relatively complete and the technology is relatively mature. Seawater alkalization and carbon sink enhancement technology is to artificially accelerate the dissolution of silicate or carbonate alkaline minerals, increase the alkalinity of seawater, and promote the dissolution of carbon dioxide in seawater, that is, artificially accelerate the solubility pump to complete the capture of atmospheric carbon dioxide. The seaweed aquaculture carbon sink enhancement technology is to artificially cultivate micro or large seaweed, use the photosynthetic carbon fixation of seaweed to convert the inorganic carbon dissolved in seawater into organic carbon, and release particulate and dissolved organic carbon into the water body, which realizes long-term carbon storage through the secondary conversion of biological carbon pump and microbial carbon pump respectively.

[0004] However, the industrial application of seawater alkalization and seaweed aquaculture to increase carbon sinks still has some bottlenecks that need to be solved. Among them, seawater alkalization and carbon sinks may increase the free silicate and carbonic acid in seawater, promote the formation of silicate / carbonate secondary minerals, and return part of the carbon dioxide dissolved in the seawater system to the atmosphere, resulting in an unknown carbon storage cycle of the technology. Seaweed aquaculture is limited by the conversion efficiency of the biological carbon pump and micro-biocarbon, and has limited carbon sink potential. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects of the prior art, and proposes a device and method for carbon dioxide capture and marine carbon sequestration, to realize the integrated process of seawater alkalization and seaweed cultivation, to quickly capture atmospheric carbon dioxide by dissolving alkaline minerals in seawater, to utilize diatom breeding to reduce the concentration of free silicate and carbonic acid in seawater, to store carbon in various forms such as inorganic / organic, particulate / dissolved, and to increase the marine carbon storage period.

[0006] The technical solution of the present invention is: a device for carbon dioxide capture and marine carbon sequestration, which includes a seawater alkalization mechanism, a diatom breeding system, a power component and a monitoring component, the power component is respectively connected to the seawater alkalization mechanism, the diatom breeding system and the monitoring component, the water outlet of the seawater alkalization mechanism is connected to the diatom breeding system, and the monitoring component is respectively connected to the seawater alkalization mechanism and the diatom breeding system;

[0007] The seawater alkalization mechanism comprises a seawater alkalization reactor, a crushing blade is arranged at the bottom of the seawater alkalization reactor, the crushing blade is connected to the power assembly, a seawater inlet I, an alkaline mineral inlet and a pressure relief port are arranged at the top of the seawater alkalization reactor, a pressure relief valve is arranged at the pressure relief port, an air pressure monitor, a carbon dioxide partial pressure monitor, a pH monitor I and a dissolved silicon monitor are arranged on the side wall of the seawater alkalization reactor, an air inlet is arranged at the bottom of the seawater alkalization reactor, a water outlet I is arranged in the middle of the side wall of the seawater alkalization reactor, and the water outlet I is connected to the diatom breeding system through a connecting pipeline;

[0008] The diatom breeding system comprises a diatom breeding pool, which is provided with a seawater inlet II, a nutrient salt monitor, a PH monitor II and a temperature probe, and a water outlet is provided at the bottom of the diatom breeding pool.

[0009] In the present invention, the power component uses one or more renewable clean energy sources such as wind energy, tidal energy and solar energy, and converts the above energy into electrical energy.

[0010] The present invention also includes a method for capturing carbon dioxide and storing ocean carbon using the above device, which includes the following steps:

[0011] S1. Dissolution and capture of carbon dioxide in seawater alkalization mechanism:

[0012] Inject seawater into the seawater alkalization reactor of the seawater alkalization mechanism through the seawater inlet I, put alkaline mineral particles into the seawater alkalization reactor through the alkaline mineral inlet, and the alkaline mineral particles directly fall to the bottom of the reactor body. Inject natural seawater accounting for 60%-80% of the volume of the entire reactor and alkaline mineral particles of 0.1% of the mass of seawater into the seawater alkalization reactor, and the particle size of the alkaline mineral particles is not more than 2mm;

[0013] The ambient atmosphere or flue gas is introduced from below the reactor water body through the air inlet at the bottom of the seawater alkalization reactor, and the crushing blades at the bottom of the reactor are started. During the rotation of the crushing blades, the alkaline mineral particles at the bottom of the reactor are crushed, thereby accelerating the dissolution of the alkaline minerals in the seawater. After the alkaline minerals are dissolved in the seawater, the alkalinity of the seawater body is increased, which promotes the dissolution of more CO2 and fixes it in the seawater in the form of bicarbonate;

[0014] When the carbon dioxide partial pressure monitor detects that the carbon dioxide partial pressure of the seawater in the reactor is lower than 300μatm, or the pH monitor I detects that the pH value of the seawater in the reactor exceeds 9, or the dissolved silicon monitor detects that the concentration of dissolved silicon in the seawater in the reactor exceeds 40μmol / L, when one of the above conditions is met, the crushing blades stop crushing and stirring, and stand for 0.5-1.0 hours to allow the alkaline minerals in the seawater to precipitate, and the seawater treated by the seawater alkalization reactor flows into the diatom breeding system;

[0015] S2. Diatom breeding and water cultivation in the diatom breeding system:

[0016] Natural seawater is injected into the diatom breeding pool through the seawater inlet II on the diatom breeding pool, and the pH value of the water in the diatom breeding pool is reduced to and controlled between 8-9 through the pH monitor II. The temperature of the water in the diatom breeding pool is controlled above 9°C through the temperature probe, and Thalassiosira wissenii is bred in the water, and the water is cultivated at the same time;

[0017] When the nutrient monitor detects that the inorganic nitrogen concentration in the water of the diatom cultivation pool is lower than 1.0μmol / L, the phosphate concentration is lower than 0.1μmol / L, or the dissolved silicon concentration is lower than 2.0μmol / L, when one of the above three conditions is met, the diatoms cultivated in the diatom breeding system shall be collected, and the water cultivated in the diatom breeding system can be released into the environmental sea area;

[0018] S3. The seawater alkalization mechanism continues to add seawater to the diatom breeding system, achieving continuous carbon dioxide capture in seawater and ocean carbon sequestration.

[0019] In the present invention, the dissolution and enrichment mechanism of alkaline minerals is as follows:

[0020] CO2+H2O+0.25Mg2SiO4→HCO3 - +0.25H4SiO4+0.5Mg 2+ .

[0021] In the above step S2, the reactor can be placed in a pressurized state to achieve the crushing and stirring of the crushing blades. At this time, the ambient atmosphere or flue gas is introduced from below the reactor water body through the air inlet at the bottom of the seawater alkalization reactor until the pressure in the reactor rises to 18-25 bar, and the air inlet is automatically closed, and all valves of the reactor are closed to make the entire reactor in a closed state. After 4-6 hours of timing, the crushing blades at the bottom of the reactor are started;

[0022] After the crushing blades stop crushing and stirring, the pressure in the reactor is released to normal pressure through the pressure relief valve at the pressure relief port on the top of the reactor.

[0023] The reactor can also be placed under normal pressure to achieve the crushing and stirring of the crushing blades. At this time, the ambient atmosphere or flue gas is introduced from below the reactor water body through the air inlet at the bottom of the seawater alkalization reactor, and the pressure relief valve is opened at the same time to keep the seawater alkalization reactor at normal pressure. At this time, other valves on the reactor are closed and the crushing blades at the bottom of the reactor are started.

[0024] The beneficial effects of the present invention are:

[0025] (1) The device uses high pressure conditions to promote the dissolution of atmospheric carbon dioxide in seawater, making the seawater acidic and promoting the dissolution of alkaline minerals. At the same time, the mechanical stirring action of the crushing blades at the bottom of the reactor further accelerates the dissolution of alkaline minerals.

[0026] (2) The alkalinized seawater has a high bicarbonate content and a high concentration of dissolved silicon, which is conducive to promoting the growth of diatoms;

[0027] (3) Compared with directly throwing alkaline mineral powder into the seaweed cultivation area to achieve the seawater alkalization-seaweed cultivation combined carbon sink process, this device system is easy to control manually, and its capture and fixation of atmospheric carbon dioxide can be monitored;

[0028] (4) By dissolving carbon dioxide in the seawater alkalization mechanism, the solution quickly enters an acidic environment, and stirring accelerates the dissolution process of alkaline minerals. The solution quickly enters an alkaline environment, so that natural seawater is converted from an acidic environment to an alkaline environment in a short period of time, reducing the activity of the original microbial population in the natural seawater and avoiding its contamination of diatom reproduction;

[0029] (5) Diatoms are grown using natural seawater, and no nitrogen and phosphorus nutrients need to be added artificially during the breeding process. The discharge of water will not cause eutrophication of seawater, and the device can also be used to purify eutrophic seawater;

[0030] (6) Diatoms absorb and assimilate dissolved silicon in alkaline seawater, avoiding the formation of secondary silicate minerals. At the same time, dissolved inorganic carbon is converted into organic carbon, which effectively prevents dissolved carbon dioxide from returning to the atmosphere.

[0031] (7) The accelerated dissolution of alkaline minerals can be achieved in the seawater alkalization reactor, and its carbon fixation efficiency can be directly monitored. Therefore, in the actual working process, the parameter details of the reactor can be adjusted at any time according to the specific environment of implementation;

[0032] (8) The power mechanism of the device described in the present invention adopts renewable clean energy and does not generate additional carbon emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the structure of a device for carbon dioxide capture and ocean carbon storage.

[0034] In the figure: 1 seawater alkalization mechanism; 2 diatom breeding system; 3 power assembly; 4 seawater alkalization reactor; 5 crushing blades; 6 seawater inlet Ⅰ; 7 alkaline mineral inlet; 8 pressure relief port; 9 air pressure monitor; 10 carbon dioxide partial pressure monitor; 11 PH monitor Ⅰ; 12 dissolved silicon monitor; 13 air inlet; 14 diatom breeding pool; 15 seawater inlet Ⅱ; 16 nutrient salt monitor; 17 PH detector Ⅱ; 18 temperature probe; 19 water outlet Ⅱ. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0036] In the following description, specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0037] Example 1

[0038] The present invention includes devices for carbon dioxide capture and ocean carbon sequestration, such as Figure 1 As shown, the device includes a seawater alkalization mechanism 1 for capturing atmospheric carbon dioxide, a diatom breeding system 2 for marine carbon sequestration, a power component 3 for providing clean renewable energy, and a monitoring component for realizing intelligent control, wherein the power component 3 is respectively connected to the seawater alkalization mechanism 1, the diatom breeding system 2, and the monitoring component, and the water outlet of the seawater alkalization mechanism 1 is connected to the water inlet of the diatom breeding system 2. The monitoring component is respectively connected to the seawater alkalization mechanism 1 and the diatom breeding system 2.

[0039] The seawater alkalization mechanism 1 includes a seawater alkalization reactor 4, and a crushing blade 5 for crushing alkaline minerals is provided at the bottom of the seawater alkalization reactor 4. The rotating shaft at the center of the crushing blade is connected to the power assembly 3. The crushing blade 5 is rotated by the power provided by the power assembly 3, thereby crushing the alkaline minerals in the seawater alkalization reactor 4. The top of the seawater alkalization reactor 4 is provided with a seawater inlet Ⅰ6, an alkaline mineral inlet 7 and a pressure relief port 8. Seawater is injected into the seawater alkalization reactor 4 through the seawater inlet Ⅰ6, and alkaline mineral particles enter the seawater alkalization reactor 4 through the alkaline mineral inlet 7. A pressure relief valve is provided at the pressure relief port 8, and the pressure of the seawater alkalization reactor 4 is relieved through the pressure relief valve. The side wall of the seawater alkalization reactor 4 is also provided with an air pressure monitor 9, a carbon dioxide partial pressure monitor 10, a pH monitor Ⅰ 11 and a dissolved silicon monitor 12. The pressure in the seawater alkalization reactor 4 is monitored in real time by the air pressure monitor 9, the carbon dioxide partial pressure value of the seawater in the seawater alkalization reactor can be obtained in real time by the carbon dioxide partial pressure monitor 10, the pH value of the seawater in the seawater alkalization reactor is monitored in real time by the pH detector Ⅰ 11, and the dissolved silicon concentration of the seawater in the seawater alkalization reactor is monitored in real time by the dissolved silicon detector 12. The lower part of the seawater alkalization reactor 4 is provided with an air inlet 13, and air or flue gas containing carbon dioxide enters the seawater alkalization reactor 4 through the air inlet 13, and the ambient atmosphere or flue gas is used as a source of carbon dioxide capture. In the present application, the kettle body of the seawater alkalization reactor 4 can withstand a pressure below 50 bar. A water outlet Ⅰ is provided in the middle of the side wall of the seawater alkalization reactor 4, and the water outlet Ⅰ is connected to the diatom breeding system 2 through a connecting pipeline.

[0040] The diatom breeding system 2 includes a diatom breeding pool 14, and the treated seawater flowing out of the water outlet of the seawater alkalization reactor 4 flows directly into the diatom breeding pool 14. The diatom breeding pool 14 is provided with a seawater inlet II 15. During the diatom breeding process, the seawater that needs to be supplemented flows into the diatom breeding pool 14 through the seawater inlet II 15. The diatom breeding pool 14 is respectively provided with a nutrient monitor 16, a pH monitor II 17 and a temperature probe 18. The nutrient monitor 16 monitors the inorganic nitrogen concentration, phosphate concentration and dissolved silicon concentration of the culture water in the diatom breeding pool 14 in real time, and the pH monitor II 17 monitors the pH value of the culture water in real time to ensure that the pH value of the culture water is maintained between 8 and 9. The temperature probe 18 monitors the temperature of the culture water in real time, so as to control the temperature of the culture water to be above 9°C. The bottom of the diatom breeding pool 14 is provided with a water outlet 19, and the water in the diatom breeding pool 14 can be directly discharged into the seawater through the water outlet 19.

[0041] The power component 3 in the present application can use one or more renewable clean energy such as wind energy, tidal energy, and solar energy, and convert the above energy into electrical energy. The power component 3 is connected to the crushing blades 5 in the seawater alkalization reactor to provide power for the rotation of the crushing blades. A heating device is provided in the diatom breeding pool 14. When the temperature in the diatom breeding pool 14 drops below 9°C, the power component 3 provides electricity to the heating device, and the heating device heats the cultivation water in the diatom breeding pool to keep the temperature of the cultivation water above 9°C. At the same time, the power component also provides electricity to each monitoring component to ensure the normal operation of the monitoring component. During idle periods, the electricity obtained by the power component can also be fed into the power grid for other purposes.

[0042] Example 2

[0043] The present application also includes a method for capturing carbon dioxide and storing ocean carbon using the above-mentioned device, which includes the following steps.

[0044] The first step is to dissolve carbon dioxide in the seawater alkalization mechanism.

[0045] The seawater is injected into the seawater alkalization reactor 4 of the seawater alkalization mechanism through the seawater inlet Ⅰ6; the alkaline mineral particles are put into the seawater alkalization reactor 4 through the alkaline mineral inlet 7, and the alkaline mineral particles fall directly to the bottom of the reactor body under the action of gravity. In the present application, the natural seawater accounting for 60%-80% of the volume of the entire reactor and the alkaline mineral particles of 0.1% of the mass of the seawater are injected into the seawater alkalization reactor 4, and the particle size of the alkaline mineral particles is not greater than 2 mm.

[0046] The ambient atmosphere or flue gas is introduced from below the reactor water body through the air inlet 13 at the bottom of the seawater alkalization reactor 4 until the pressure in the reactor rises to 18-25 bar, and the air inlet 13 is automatically closed. At this time, all valves on the reactor are closed to put the entire reactor in a closed state. The entire reactor is closed for 4-6 hours, during which the carbon dioxide is fully dissolved in the seawater. The crushing blades 5 at the bottom of the reactor are started. During the rotation of the crushing blades, the alkaline mineral particles at the bottom of the reactor are crushed, thereby accelerating the dissolution of the alkaline minerals in the seawater. After the alkaline minerals are dissolved in the seawater, the alkalinity of the seawater body is increased, which can promote the dissolution of more CO2 and fix it in the seawater in the form of bicarbonate. The dissolution and sink mechanism of alkaline minerals is as follows:

[0047] CO2+H2O+0.25Mg2SiO4→HCO3 - +0.25H4SiO4+0.5Mg 2+

[0048] When the carbon dioxide partial pressure monitor 10 detects that the carbon dioxide partial pressure of the seawater in the reactor is lower than 300μatm, or the pH monitor Ⅰ11 detects that the pH value of the seawater in the reactor exceeds 9, or the dissolved silicon monitor 12 detects that the concentration of dissolved silicon in the seawater in the reactor exceeds 40μmol / L, when one of the above conditions is met, the crushing blade 5 stops crushing and stirring, and the pressure in the reactor is released to normal pressure through the pressure relief valve at the pressure relief port 8 at the top of the reactor. After standing for 0.5-1.0 hours to allow the alkaline minerals in the seawater to precipitate, the water outlet Ⅰ on the reactor is opened, and the seawater treated by the seawater alkalization reactor flows into the diatom breeding system 2.

[0049] The second step is to breed diatoms and cultivate water bodies in the diatom breeding system 2.

[0050] The diatoms in the present application are selected from the model algae of diatom cultivation, Helichthys wissenii. In the diatom breeding system, the diatoms are bred using the alkaline seawater rich in silicon and high in inorganic carbon content that flows out of the alkaline seawater mechanism.

[0051] Based on the total alkalinity and pH value detected by the alkalinized seawater flowing out of the seawater alkalinization mechanism, since its pH value exceeds 9, in order to make the pH value of the water body more suitable for the breeding of diatoms, natural seawater is injected into the diatom breeding pool 14 through the seawater inlet II 15 on the diatom breeding pool 14, and the pH value of the water body in the diatom breeding pool 14 is reduced to and controlled between 8 and 9 through the pH monitor II 17. The temperature of the water body in the diatom breeding pool 14 is controlled to be above 9°C through the temperature probe 18, and Thalassiosira wissenii is bred in the water body, and the water body is cultivated at the same time.

[0052] When the nutrient monitor 16 detects that the inorganic nitrogen concentration of the water in the diatom cultivation pond is lower than 1.0 μmol / L, the phosphate concentration is lower than 0.1 μmol / L or the dissolved silicon concentration is lower than 2.0 μmol / L, when one of the above three conditions is met, the diatoms bred in the diatom breeding system can be collected. The collected diatoms can be used as feed for marine aquaculture, and the carbon fixed in the algae body is transferred through the marine food chain. Part of the fixed carbon is settled in the form of biological debris through the biological pump and buried on the seabed, completing long-term carbon storage.

[0053] At the same time, the water cultivated by the diatom breeding system can be released into the environmental sea area. The water cultivated by the diatom breeding system carries algae debris and dissolved organic carbon, which can be directly discharged into the surrounding sea area without treatment. The algae debris discharged into the surrounding sea area partially settles and is buried in the seabed, while the dissolved organic carbon is transformed into inert dissolved organic carbon by marine microorganisms, completing long-term carbon storage.

[0054] The third step is to dissolve carbon dioxide and alkalize seawater in the seawater alkalization mechanism during the diatom breeding and water cultivation process in the diatom breeding system. Therefore, after the water cultivated in the diatom breeding system in the second step is discharged into the sea, seawater is continuously replenished from the seawater alkalization mechanism to the diatom breeding system, thus achieving continuous carbon dioxide capture in seawater and ocean carbon sequestration.

[0055] Example 3

[0056] Different from Example 2, in the method for carbon dioxide capture and ocean carbon sequestration described in this example, in the second step, Example 2 adopts a pressurized dissolution process, while this example adopts a normal pressure dissolution process.

[0057] The ambient atmosphere or flue gas is introduced from below the water body of the seawater alkalization reactor 4 through the air inlet 13 at the bottom of the reactor, and the pressure relief valve is opened at the same time to keep the seawater alkalization reactor 4 at normal pressure. The other valves on the reactor are closed, and the crushing blades 5 at the bottom of the reactor are started. During the rotation of the crushing blades, the alkaline mineral particles at the bottom of the reactor are crushed, thereby accelerating the dissolution of the alkaline minerals in the seawater.

[0058] The rest is the same as Example 2.

[0059] The above is a detailed introduction to the device and method for carbon dioxide capture and ocean carbon sequestration provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. Various modifications to these embodiments will be obvious to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for capturing carbon dioxide and storing marine carbon, characterized in that: The method is implemented using a device for carbon dioxide capture and marine carbon sequestration, the device comprising a seawater alkalization mechanism (1), a diatom breeding system (2), a power component (3) and a monitoring component, the power component (3) being connected to the seawater alkalization mechanism (1), the diatom breeding system (2) and the monitoring component respectively, the water outlet of the seawater alkalization mechanism (1) being connected to the diatom breeding system (2), and the monitoring component being connected to the seawater alkalization mechanism (1) and the diatom breeding system (2) respectively; The seawater alkalization mechanism (1) comprises a seawater alkalization reactor (4), the bottom of which is provided with a crushing blade (5), which is connected to a power assembly (3), the top of which is provided with a seawater inlet I (6), an alkaline mineral inlet (7) and a pressure relief port (8), the pressure relief port (8) being provided with a pressure relief valve, the side wall of the seawater alkalization reactor (4) being provided with an air pressure monitor (9), a carbon dioxide partial pressure monitor (10), a pH monitor I (11) and a dissolved silicon monitor (12), the lower part of the seawater alkalization reactor (4) being provided with an air inlet (13), the middle part of the side wall of the seawater alkalization reactor (4) being provided with a water outlet I, which is connected to a diatom breeding system (2) via a connecting pipeline; The diatom breeding system (2) comprises a diatom breeding pool (14), the diatom breeding pool (14) is provided with a seawater inlet II (15), the diatom breeding pool (14) is provided with a nutrient salt monitor (16), a pH monitor II (17) and a temperature probe (18), and the bottom of the diatom breeding pool (14) is provided with a water outlet (19); include The following steps, S1. Dissolution and capture of carbon dioxide in seawater alkalization mechanism: Inject seawater into the seawater alkalization reactor of the seawater alkalization mechanism through the seawater inlet I, put alkaline mineral particles into the seawater alkalization reactor through the alkaline mineral inlet, and the alkaline mineral particles directly fall to the bottom of the reactor body. Inject natural seawater accounting for 60%-80% of the volume of the entire reactor and alkaline mineral particles of 0.1% of the mass of seawater into the seawater alkalization reactor, and the particle size of the alkaline mineral particles is not more than 2mm; The ambient atmosphere or flue gas is introduced from below the reactor water body through the air inlet at the bottom of the seawater alkalization reactor, and the crushing blades at the bottom of the reactor are started. During the rotation of the crushing blades, the alkaline mineral particles at the bottom of the reactor are crushed, thereby accelerating the dissolution of the alkaline minerals in the seawater. After the alkaline minerals are dissolved in the seawater, the alkalinity of the seawater body is increased, which promotes the dissolution of more CO2 and fixes it in the seawater in the form of bicarbonate; When the carbon dioxide partial pressure monitor detects that the carbon dioxide partial pressure of the seawater in the reactor is lower than 300μatm, or the pH monitor I detects that the pH value of the seawater in the reactor exceeds 9, or the dissolved silicon monitor detects that the concentration of dissolved silicon in the seawater in the reactor exceeds 40μmol / L, when one of the above conditions is met, the crushing blades stop crushing and stirring, and stand for 0.5-1 hour to allow the alkaline minerals in the seawater to precipitate, and the seawater treated by the seawater alkalization reactor flows into the diatom breeding system; S2. Diatom breeding and water cultivation in the diatom breeding system: Through the seawater inlet Ⅱ on the diatom breeding pool, natural seawater is injected into the diatom breeding pool, and the pH value of the water in the diatom breeding pool is reduced to and controlled between 8-9 through the pH monitor Ⅱ. Through the temperature probe, the temperature of the water in the diatom breeding pool is controlled above 9℃, and Thalassiosira wissenii is bred in the water body, and the water body is cultivated at the same time; When the nutrient monitor detects that the inorganic nitrogen concentration in the water of the diatom cultivation pool is lower than 1.0μmol / L, the phosphate concentration is lower than 0.1μmol / L, or the dissolved silicon concentration is lower than 2.0μmol / L, when one of the above three conditions is met, the diatoms cultivated in the diatom breeding system are collected, and the water cultivated in the diatom breeding system is released into the environmental sea area; The water body after the diatom breeding system carries algae debris and dissolved organic carbon and flows directly into the environmental sea area: the algae debris flowing into the surrounding sea area is partially buried in the seabed, and the dissolved organic carbon is transformed into inert dissolved organic carbon by marine microorganisms, completing long-term carbon storage; S3. The seawater alkalization mechanism continues to add seawater to the diatom breeding system, achieving continuous carbon dioxide capture in seawater and ocean carbon sequestration.

2. The method according to claim 1, characterized in that The power component (3) uses one or more renewable clean energy sources such as wind energy, tidal energy and solar energy, and converts the above energy into electrical energy.

3. The method according to claim 1, characterized in that The mechanism of dissolution and enrichment of alkaline minerals is as follows: CO2 + H2O + 0.25 Mg2SiO4 → HCO3 - + 0.25 H4SiO4 +0.5 Mg 2+ 。 4. The method according to claim 1, characterized in that: In the above step S2, ambient air or flue gas is introduced from below the water body of the reactor through the air inlet at the bottom of the seawater alkalization reactor until the pressure in the reactor rises to 18-25 bar, and the air inlet is automatically closed, and all valves of the reactor are closed to make the entire reactor in a closed state. After 4-6 hours of timing, the crushing blades at the bottom of the reactor are started; After the crushing blades stop crushing and stirring, the pressure in the reactor is released to normal pressure through the pressure relief valve at the pressure relief port on the top of the reactor.

5. The method according to claim 1, characterized in that In the above step S2, ambient atmosphere or flue gas is introduced from below the water body of the reactor through the air inlet at the bottom of the seawater alkalization reactor, and the pressure relief valve is opened at the same time to keep the seawater alkalization reactor at normal pressure. At this time, other valves on the reactor are closed and the crushing blades at the bottom of the reactor are started.

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