Carbon capture and storage system and carbon capture and storage method

Abstract

The invention relates to the technical field of flue gas treatment, in particular to a carbon capture and storage system and a carbon capture and storage method.The carbon capture and storage system comprises a waste gas absorption unit, an amine liquid circulation unit, a carbon dioxide gas salinization unit and a carbon sequestration unit which are communicated in sequence; the system further comprises a limestone slurry pulping and filling unit; and the limestone slurry pulping and filling unit is communicated with the carbon dioxide gas salinization unit. The carbon capture and storage method is a brand-new organic amine decarburization and permanent carbon sequestration method provided on the basis of the principle of enhancing rock weathering; compared with a traditional carbon sequestration method that carbon dioxide is transported through compression and liquefaction and stored in an underground salt water layer, the method has the advantages that the carbon capturing and storing process is short, high-pressure and low-temperature high-energy-consumption equipment does not need to be used, the captured carbon dioxide gas does not need to be stored and transported at low temperature, energy consumption can be reduced, the carbon sequestration cost is saved, and the carbon sequestration efficiency is improved. The carbon dioxide escape phenomenon in the storage and transportation process can be avoided, and the carbon sequestration efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas treatment, and in particular to a carbon capture and storage system and a carbon capture and storage method. Background Art

[0002] Large amounts of carbon dioxide emitted from fossil fuels are the main cause of global warming. Capturing, utilizing and storing the emitted carbon dioxide is one of the most effective means to achieve large-scale carbon emission reductions and address climate change. Currently, chemical absorption carbon capture technology is usually used to capture carbon dioxide after the combustion of fossil fuels.

[0003] The organic amine decarbonization and storage method is one of the most important chemical absorption carbon capture technologies; and the existing organic amine decarbonization and storage method is to use an amine machine to contact with carbon-containing waste gas and carry out absorption reaction, and then use the principle of rich liquid heating and reversible desorption to capture carbon dioxide from the waste gas; then, use a compressor booster refrigeration machine to cool and liquefy and store the carbon dioxide in a liquid tank; and transport the liquid carbon dioxide to the underground where it can be permanently sealed; thereby achieving the purpose of capturing and storing carbon dioxide.

[0004] In the process of capturing and storing carbon dioxide using the organic amine decarbonization storage method, the compression, liquefaction, storage, transportation, and sealing of carbon dioxide consume a lot of energy; at least 300KWh of energy is consumed for each ton of carbon dioxide compressed, liquefied, stored, and sealed; in addition, since carbon dioxide is sealed using low temperature, high pressure storage, and high pressure saline layer storage, the capture and sealing process of this method is relatively long, and during this period it is also necessary to ensure that the carbon dioxide is in a liquid state; in order to maintain the liquid state of carbon dioxide, a high amount of energy is also required.

[0005] The present invention provides a carbon capture and storage system and a carbon capture and storage method to solve the problems of the existing organic amine decarbonization and storage method in the prior art, such as the carbon capture and storage process being too long, high energy consumption, high cost, and large consumption of manpower and material resources. Summary of the invention

[0006] The purpose of the present invention is to provide a carbon capture and storage system and a carbon capture and storage method to solve the problems of the existing organic amine decarbonization and storage method in the prior art, such as the carbon capture and storage process being too long, high energy consumption, high cost, and large consumption of manpower and material resources.

[0007] The technical solution of the present invention is: a carbon capture and storage system, comprising a waste gas absorption unit, an amine liquid circulation unit, a carbon dioxide gas salification unit, a carbon fixation and storage unit, and a limestone slurry slurry filling unit; wherein the waste gas absorption unit comprises a cooling tower and an absorption tower; the upper part of the cooling tower is connected to a flue gas source through a flue gas conveying pipeline, and the bottom is connected to the absorption tower, and a seawater spraying device is arranged inside; a bypass valve is arranged on the flue gas conveying pipeline between the cooling tower and the flue gas source; the seawater spraying device is connected to the output end of a seawater pump through a water conveying pipeline; a seawater discharge port is also arranged at the bottom of the cooling tower; a lean amine liquid spraying device is arranged at the upper end of the absorption tower, and an exhaust port is arranged at the top; The amine liquid circulation unit comprises a desorption tower, a lean-rich liquid heat exchanger, and a reboiler; the reboiler is connected to the desorption tower; the rich liquid inlet of the lean-rich liquid heat exchanger is connected to the bottom of the absorption tower, and the rich liquid outlet is connected to the top of the desorption tower; the lean liquid inlet of the lean-rich liquid heat exchanger is connected to the bottom of the desorption tower, and the lean liquid outlet is connected to the top of the absorption tower after passing through a lean liquid cooler; The carbon dioxide gas salting unit comprises a regeneration gas cooler, a compressor, and a carbonization tank; the input end of the regeneration gas cooler is connected to the top of the desorption tower, and the output end is connected to the input end of the compressor; the output end of the compressor is connected to the bottom of the carbonization tank; the top of the carbonization tank is provided with an air outlet; the air outlet is connected to the input end of the compressor through an air flow pipeline; The carbon sequestration unit includes a slag discharge pump, a filter, and a mixer; the input end of the slag discharge pump is connected to the bottom of the carbonization tank, and the output end is connected to the filter; the upper end of the filter is connected to the mixer; the upper end of the mixer is connected to the output end of the seawater pump through a water flow pipeline, and a drain is provided at the lower end; the drain is connected to the water flow pipeline leading to the deep sea discharge area; a pH meter is also provided at the drain; The limestone slurry preparation and filling unit comprises a limestone slurry pool; the upper part of the limestone slurry pool is respectively connected with the limestone powder bin and the output end of the seawater pump, and the bottom is connected with the upper part of the carbonization tank.

[0008] Preferably, the bottom of the cooling tower is connected to the bottom of the absorption tower through an air flow pipeline, and a booster fan is provided on the air flow pipeline between the cooling tower and the absorption tower.

[0009] Preferably, the amine liquid circulation unit also includes a rich liquid pump and a lean liquid pump; the input end of the rich liquid pump is connected to the bottom of the absorption tower, and the output end is connected to the rich liquid inlet of the lean-rich liquid heat exchanger; the input end of the lean liquid pump is connected to the bottom of the desorption tower, and the output end is connected to the lean liquid inlet of the lean-rich liquid heat exchanger.

[0010] Preferably, a pressure reducing valve is provided on the air flow pipeline between the air outlet and the compressor.

[0011] Preferably, a bubble distributor and an agitator are provided in the carbonization tank; the bubble distributor is connected to the output end of the compressor.

[0012] Preferably, the bottom of the filter is connected to the limestone slurry pool; the upper end of the filter is also provided with a gas outlet; the gas outlet is connected to the input end of the compressor through an air flow pipeline.

[0013] The present invention also provides a method for carbon capture and storage using the above carbon capture and storage system, the method specifically comprising the following steps: S1. When the waste gas needs to be decarbonized, the bypass valve is opened, and the waste gas is transported to the cooling tower through the flue gas conveying pipeline for seawater spraying. After cooling to 40-60°C, the waste gas flows into the absorption tower from the bottom of the absorption tower, contacts with the lean amine liquid sprayed in the absorption tower, and is absorbed by the lean amine liquid to form rich amine liquid and relatively pure gas. The relatively pure gas flows out from the gas outlet; S2, the formed rich amine liquid is heated to 95-110°C through the lean-rich liquid heat exchanger and then transported to the top of the desorption tower, sprayed from the top of the desorption tower to the bottom, and then heated and desorbed carbon dioxide gas after absorbing the steam heat generated by the reboiler to form lean amine liquid; S3, the formed lean amine liquid is cooled twice by the lean-rich liquid heat exchanger and the lean liquid cooler, and then transported to the top of the absorption tower. At the same time, the desorbed carbon dioxide gas is first cooled by the regeneration gas cooler, and then pressurized to 4-6 bar by the compressor and transported to the bottom of the carbonization tank. After that, based on the principle of enhanced rock weathering, under acidic conditions, the desorbed carbon dioxide gas reacts with the limestone slurry to generate soluble calcium bicarbonate. Part of the unreacted carbon dioxide gas is transported to the compressor from the gas outlet at the top of the carbonization tank, and is transported to the bottom of the carbonization tank again after compression; S4, start the slag pump, the calcium bicarbonate generated is transported to the filter together with the limestone slurry at the bottom of the carbonating tank for filtration, forming clarified liquid and limestone slag, and at the same time, limestone powder and seawater are transported in the limestone slurry pool to prepare limestone slurry, and the limestone slurry pump is started to transport limestone slurry to the top of the carbonating tank; S5. The clarified liquid formed in the filter is transported to the mixer, mixed with seawater in proportion to form a mixed liquid with a pH value of not less than 6, and the mixed liquid is discharged to the deep sea discharge area through the discharge port. At the same time, the limestone slurry residue in the filter is transported to the limestone slurry pool for preparing limestone slurry.

[0014] Preferably, in said S2, cooling the formed lean amine liquid twice comprises cooling it to 60-70°C through a lean-rich liquid heat exchanger and cooling it to 30-45°C through a lean liquid cooler.

[0015] Preferably, in S5, the ratio of clarified liquid to seawater is 1:(10-1000).

[0016] Compared with the prior art, the advantages of the present invention are: (1) The present invention provides a carbon capture and storage system and a carbon capture and storage method, which is a new organic amine decarbonization and permanent carbon fixation method based on the principle of enhanced rock weathering. The carbon capture and storage method first captures carbon dioxide gas in flue gas by organic amine, then decomposes carbon dioxide gas in a desorption tower, and then reacts the decomposed carbon dioxide gas with limestone slurry under acidic conditions to generate soluble calcium bicarbonate, and finally seals the calcium bicarbonate in the deep sea discharge area. Compared with the traditional carbon fixation method of compressing and liquefying carbon dioxide for transportation and sealing it in underground saline aquifers, The carbon capture and storage process of this carbon capture and storage method is relatively short, and does not require the use of high-pressure, low-temperature, high-energy-consuming equipment during the carbon capture and storage process, nor does it require low-temperature storage and transportation of the captured carbon dioxide gas. This can not only reduce energy consumption and save carbon fixation costs, but also avoid the phenomenon of carbon dioxide escape during storage and transportation, thereby improving carbon fixation efficiency; at the same time, it can also reduce the consumption of manpower and material resources; it solves the problems of the existing organic amine decarbonization and storage method in the prior art, such as its long carbon capture and storage process, high energy consumption, high cost, and large consumption of manpower and material resources.

[0017] (2) The present invention provides a carbon capture and storage system and a carbon capture and storage method. The carbon capture and storage method converts the decomposed carbon dioxide gas into calcium bicarbonate by reacting it with limestone slurry under acidic conditions. Calcium bicarbonate can stably exist in the form of bicarbonate ions and calcium ions under deep sea and low temperature conditions, so that the carbon capture and storage method can achieve the purpose of permanent carbon fixation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the structure of the carbon capture and storage system of the present invention; Among them: 1. Cooling tower; 2. Absorption tower; 3. Bypass valve; 4. Seawater pump; 5. Seawater outlet; 6. Exhaust port; 7. Desorption tower; 8. Lean and rich liquid heat exchanger; 9. Reboiler; 10. Lean liquid cooler; 11. Regeneration gas cooler; 12. Compressor; 13. Carbonization tank; 14. Gas outlet; 15. Slag pump; 16. Filter; 17. Mixer; 18. Drain; 19. pH meter; 20. Limestone slurry pool; 21. Limestone powder silo; 22. Booster fan; 23. Rich liquid pump; 24. Lean liquid pump; 25. Pressure reducing valve; 26. Bubble distributor; 27. Agitator; 28. Gas outlet; 29. ​​Limestone slurry pump. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with specific embodiments: A carbon capture and storage system, such as Figure 1 As shown, it includes a waste gas absorption unit, an amine liquid circulation unit, a carbon dioxide gas salification unit, and a carbon fixation storage unit which are connected in sequence; the carbon capture and storage system also includes a limestone slurry slurry filling unit; and the limestone slurry slurry filling unit is connected to the carbon dioxide gas salification unit.

[0020] The exhaust gas absorption unit includes a cooling tower 1 and an absorption tower 2; the upper part of the cooling tower 1 is connected to the exhaust gas source through a flue gas delivery pipeline, and a bypass valve 3 is arranged on the flue gas delivery pipeline between the cooling tower 1 and the exhaust gas source; by opening the bypass valve 3, the exhaust gas to be decarbonized can be transported to the cooling tower 1 for cooling treatment; a seawater spraying device is arranged at the upper end of the cooling tower 1; the seawater spraying device is connected to the output end of a seawater pump 4 outside the cooling tower 1 through a water delivery pipeline, and the seawater is transported to the cooling tower 1, sprayed from the upper end of the cooling tower 1 to the bottom thereof, and fully contacted and mixed with the exhaust gas transported to the cooling tower 1, thereby reducing the temperature of the exhaust gas; the bottom of the cooling tower 1 is connected to the absorption tower 2, and is used to transport the exhaust gas after the spray cooling treatment to the absorption tower 2; a seawater discharge port 5 is also arranged at the bottom of the cooling tower 1, and a water flow pipeline leading to the seawater discharge area is connected to the seawater discharge port 5, which is used to discharge the seawater sprayed to the bottom of the cooling tower 1 into the sea; a lean amine liquid spraying device is provided at the upper end of the absorption tower 2, which is used to spray the lean amine liquid from the upper end of the absorption tower 2 to the filler near the bottom of the absorption tower 2, contact with the exhaust gas transported into the absorption tower 2, and absorb the carbon dioxide gas in the exhaust gas to form rich amine liquid and relatively pure gas; an exhaust port 6 is provided at the top of the absorption tower 2, which is used to discharge the relatively pure gas without carbon dioxide absorbed by the lean amine liquid in the absorption tower 2 into the atmosphere or transport it to a subsequent gas treatment unit; the bottom of the cooling tower 1 is connected to the bottom of the absorption tower 2 through an airflow pipeline, and a booster fan 22 is also provided on the airflow pipeline between the cooling tower 1 and the absorption tower 2, which is used to increase the pressure of the exhaust gas transported into the absorption tower 2, increase the flow rate of the exhaust gas and the airflow energy, so that the exhaust gas is fully mixed with the lean amine liquid in the absorption tower 2, so that the carbon dioxide gas in the exhaust gas is fully contacted with the lean amine liquid and absorbed by the lean amine liquid, thereby realizing the capture of the carbon dioxide gas in the exhaust gas.

[0021] The amine liquid circulation unit includes a desorption tower 7, a lean-rich liquid heat exchanger 8, and a reboiler 9; the reboiler 9 is connected to the desorption tower 7 and is connected to a position near the bottom of the desorption tower 7, i.e., the packing; the rich liquid inlet of the lean-rich liquid heat exchanger 8 is connected to the bottom of the absorption tower 2, and the rich liquid outlet of the lean-rich liquid heat exchanger 8 is connected to the top of the desorption tower 7, which is used to heat the rich amine liquid at the bottom of the absorption tower 2 and transport it to the top of the desorption tower 7, and then spray it from the top of the desorption tower 7 to the packing near the bottom of the desorption tower 7 through the spraying device at the top of the desorption tower 7; the rich amine liquid sprayed to the packing absorbs the reboiler 9 generated The steam heat heats up and desorbs carbon dioxide to form a lean amine liquid containing only a small amount of carbon dioxide, and flows to the bottom of the desorption tower 7; the lean liquid inlet of the lean-rich liquid heat exchanger 8 is connected to the bottom of the desorption tower 7, and the lean liquid outlet of the lean-rich liquid heat exchanger 8 is connected to the top of the absorption tower 2 after passing through the lean liquid cooler 10, so that the lean amine liquid containing only a small amount of carbon dioxide at the bottom of the desorption tower 7 is cooled twice through the lean-rich liquid heat exchanger 8 and the lean liquid cooler 10, and then transported to the top of the absorption tower 2, and sprayed from the top of the absorption tower 2 to the filling area near the bottom of the absorption tower 2 for recycling. In order to ensure continuous and stable mutual circulation and transportation between the rich amine liquid and the lean amine liquid formed in the absorption tower 2 and the desorption tower 7, so as to achieve the effect of recycling the organic amine liquid, the amine liquid circulation unit also includes a rich liquid pump 23 and a lean liquid pump 24; the input end of the rich liquid pump 23 is connected to the bottom of the absorption tower 2, and the output end is connected to the rich liquid inlet of the lean-rich liquid heat exchanger 8, so as to pump the rich amine liquid formed in the absorption tower 2 into the lean-rich liquid heat exchanger 8 and transport it to the desorption tower 7; similarly, the input end of the lean liquid pump 24 is connected to the bottom of the desorption tower 7, and the output end is connected to the lean liquid inlet of the lean-rich liquid heat exchanger 8.

[0022] The carbon dioxide gas salification unit includes a regeneration gas cooler 11, a compressor 12, and a carbonization tank 13; the input end of the regeneration gas cooler 11 is connected to the top of the desorption tower 7, and the output end is connected to the input end of the compressor 12; the output end of the compressor 12 is connected to the bottom of the carbonization tank 13; the carbon dioxide gas desorbed in the desorption tower 7 is cooled and dehydrated by the regeneration gas cooler 11, and then flows into the compressor 12, and is transported to the carbonization tank 13 after being pressurized by the compressor 12; based on the principle of rock weathering, under acidic conditions, the carbon dioxide gas is mixed with the limestone slurry inside the carbonization tank 13 and reacts to form soluble calcium bicarbonate. In order to fully mix the carbon dioxide gas with the limestone slurry in the carbonization tank 13 and fully react, a bubble distributor 26 and an agitator 27 can be set in the carbonization tank 13; the bubble distributor 26 is connected to the output end of the compressor 12; the carbon dioxide gas transported to the carbonization tank 13 by the compressor 12 is separated into tiny bubbles by the bubble distributor 26, thereby improving the dissolution efficiency of carbon dioxide in the limestone slurry, thereby increasing the contact rate between the carbon dioxide gas and the limestone slurry, and improving the reaction efficiency; and, under the stirring action of the agitator 27, the carbon dioxide gas can be accelerated to fully mix and react with the limestone slurry in the carbonization tank 13, which can further improve the conversion rate of carbon dioxide.

[0023] The carbon fixation and storage unit includes a slag pump 15, a filter 16, and a mixer 17; the input end of the slag pump 15 is connected to the bottom of the carbonization tank 13, and the output end is connected to the filter 16, which is used to transport the soluble calcium bicarbonate and limestone slurry generated by the reaction at the bottom of the carbonization tank 13 to the filter 16 for filtration; the upper end of the filter 16 is connected to the mixer 17, and the upper end of the mixer 17 is connected to the output end of the seawater pump 4 through a water flow pipeline, and the lower end is provided with a drain 18, and the drain 18 is connected to the water flow pipeline leading to the deep sea discharge area; it is used to transport the clarified liquid separated in the filter 16 to the mixer 17, and mix it with the seawater from the seawater pump 4 in the mixer 17 to form a mixed liquid, and then discharge the mixed liquid to the deep sea discharge area through the drain 18 and the water flow pipeline, so as to achieve the purpose of permanent carbon fixation and storage; a pH meter 19 is also provided at the drain 18 to monitor the pH value of the mixed liquid of the clarified liquid and seawater; ensure that the pH value of the mixed liquid meets the requirements before it is discharged to the deep sea. A gas outlet 28 is also provided at the upper end of the filter 16; the gas outlet 28 is connected to the input end of the compressor 12 through an air flow pipeline, and is used to transport the carbon dioxide gas transported to the filter 16 along with the soluble calcium bicarbonate and limestone slurry to the carbon dioxide gas salification unit for further salification.

[0024] The limestone slurry preparation and filling unit includes a limestone slurry pool 20; the upper part of the limestone slurry pool 20 is respectively connected to the limestone powder bin 21 and the output end of the seawater pump 4, so as to add the ultrafine limestone powder and seawater in the limestone powder bin 21 into the limestone slurry pool 20, and mix them evenly in the limestone slurry pool 20 to form limestone slurry; an agitator 27 is also provided in the limestone slurry pool 20, and the agitator 27 is used to stir the limestone powder and seawater in the process of adding the limestone powder and seawater into the limestone slurry pool 20, so as to help quickly and evenly mix the limestone powder and seawater; the bottom of the limestone slurry pool 20 is connected to the upper part of the carbonization tank 13 through a slurry conveying pipeline, and a limestone slurry pump 29 is provided on the slurry conveying pipeline connecting the limestone slurry pool and the carbonization tank; the limestone slurry in the limestone slurry pool 20 is pumped into the carbonization tank 13 through the limestone slurry pump 29 to participate in the reaction. The bottom of the filter 16 is also connected to the limestone slurry pool 20; it is used to transport the limestone precipitate formed in the lower layer of the filter 16 to the limestone slurry pool 20, and together with the ultra-fine limestone powder as a raw material, prepare limestone slurry.

[0025] The method for carbon capture and storage using the above carbon capture and storage system specifically comprises the following steps: S1. When the exhaust gas needs to be decarbonized, the bypass valve is opened, and the exhaust gas is transported to the cooling tower through the flue gas conveying pipeline for seawater spraying. The seawater sprayed in the cooling tower is fully in contact with the flue gas and absorbs the heat brought by the flue gas, so that the flue gas is cooled to a range of 40-60°C; then, it flows into the absorption tower from the bottom of the absorption tower, contacts with the lean amine liquid sprayed in the absorption tower, and is absorbed by the lean amine liquid to form rich amine liquid and relatively pure gas, and the relatively pure gas is discharged from the exhaust port at the top of the absorption tower into the atmosphere or transported to the subsequent gas treatment unit. Among them, the flue gas is transported to the cooling tower at a gas flow rate of 50-500L / h; the lean amine liquid in the absorption tower can be an aqueous solution of one of methyldiethanolamine, ethanolamine, triethylenetetramine, etc. or a mixed aqueous solution of multiple kinds; the concentration of carbon dioxide gas in the relatively pure gas is below 2.0% (mole%).

[0026] S2. The rich amine liquid is heated to 95-110°C in the rich-lean liquid heat exchanger and then transported to the top of the desorption tower, where it is sprayed from the top to the bottom. The rich amine liquid absorbs the steam heat generated by the bottom reboiler, heats up, desorbs carbon dioxide gas, forms lean amine liquid, and flows to the bottom of the desorption tower.

[0027] S3, the lean amine liquid at the bottom of the desorption tower is first cooled to 60-70°C through the lean-rich liquid heat exchanger, and then cooled to 30-45°C through the lean liquid cooler. After that, the lean amine liquid is transported to the top of the absorption tower and sprayed from the top of the absorption tower to the bottom of the absorption tower; at the same time, the desorbed carbon dioxide gas is first cooled and dehydrated through the regeneration gas cooler, and then pressurized to 4-6 bar by the compressor and transported to the bottom of the carbonization tank; then, based on the principle of enhanced rock weathering, under acidic conditions, the desorbed carbon dioxide gas is absorbed and reacted with the limestone slurry to generate soluble calcium bicarbonate. The reaction equation is: ; Part of the unreacted carbon dioxide gas is transported to the compressor from the gas outlet at the top of the carbonization tank, and then transported to the bottom of the carbonization tank again after compression.

[0028] S4. Start the slag discharge pump and transport the generated calcium bicarbonate and the limestone slurry at the bottom of the carbonization tank to the filter for filtration at a flow rate of 5-100L / h to form clarified liquid and limestone slurry. At the same time, transport limestone powder and seawater into the limestone slurry pool to prepare limestone slurry, and start the limestone slurry pump to transport the limestone slurry to the top of the carbonization tank at a flow rate of 5-100L / h.

[0029] S5. The clarified liquid formed in the filter is transported to the mixer and mixed with seawater in a ratio of 1: (10-1000) to form a mixed liquid with a pH value of not less than 6, and the mixed liquid is discharged into the deep sea discharge area through the discharge port to achieve the purpose of carbon sequestration; at the same time, the limestone slurry residue in the filter is transported to the limestone slurry pool for the preparation of limestone slurry.

[0030] The carbon capture and storage method adopts the principle of accelerated rock weathering to fix carbon and seal it. Compared with the traditional carbon fixation method of compressing and liquefying carbon dioxide for transportation and sealing it in underground saline aquifers, the carbon capture and storage method does not require high-pressure, low-temperature, high-energy-consuming equipment, nor does it require low-temperature storage and transportation; it not only saves the cost consumed in the low-temperature storage, transportation and sealing process, but also avoids the occurrence of carbon dioxide escape during transportation; at the same time, it greatly shortens the carbon fixation process and reduces the energy consumption of carbon fixation. In addition, since calcium bicarbonate exists in the form of bicarbonate ions and calcium ions in seawater, and can exist stably under deep sea and low temperature conditions, the carbon capture and storage method can better achieve the purpose of carbon fixation and sealing.

[0031] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the scope of protection of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. A carbon capture and storage system, characterized in that: It includes waste gas absorption unit, amine liquid circulation unit, carbon dioxide gas salification unit, carbon fixation storage unit and limestone slurry preparation and injection unit; The exhaust gas absorption unit comprises a cooling tower and an absorption tower; the upper part of the cooling tower is connected to the flue gas source through a flue gas delivery pipeline, and the bottom is connected to the absorption tower, and a seawater spraying device is arranged inside; a bypass valve is arranged on the flue gas delivery pipeline between the cooling tower and the flue gas source; the seawater spraying device is connected to the output end of the seawater pump through a water delivery pipeline; a seawater discharge port is also arranged at the bottom of the cooling tower; a lean amine liquid spraying device is arranged at the upper end of the absorption tower, and an exhaust port is arranged at the top; The amine liquid circulation unit comprises a desorption tower, a lean-rich liquid heat exchanger, and a reboiler; the reboiler is connected to the desorption tower; the rich liquid inlet of the lean-rich liquid heat exchanger is connected to the bottom of the absorption tower, and the rich liquid outlet is connected to the top of the desorption tower; the lean liquid inlet of the lean-rich liquid heat exchanger is connected to the bottom of the desorption tower, and the lean liquid outlet is connected to the top of the absorption tower after passing through a lean liquid cooler; The carbon dioxide gas salting unit comprises a regeneration gas cooler, a compressor, and a carbonization tank; the input end of the regeneration gas cooler is connected to the top of the desorption tower, and the output end is connected to the input end of the compressor; the output end of the compressor is connected to the bottom of the carbonization tank; the top of the carbonization tank is provided with an air outlet; the air outlet is connected to the input end of the compressor through an air flow pipeline; The carbon sequestration unit includes a slag discharge pump, a filter, and a mixer; the input end of the slag discharge pump is connected to the bottom of the carbonization tank, and the output end is connected to the filter; the upper end of the filter is connected to the mixer; the upper end of the mixer is connected to the output end of the seawater pump through a water flow pipeline, and a drain is provided at the lower end; the drain is connected to the water flow pipeline leading to the deep sea discharge area; a pH meter is also provided at the drain; The limestone slurry preparation and filling unit comprises a limestone slurry pool; the upper part of the limestone slurry pool is respectively connected with the limestone powder bin and the output end of the seawater pump, and the bottom is connected with the upper part of the carbonization tank.

2. A carbon capture and storage system according to claim 1, characterized in that: The bottom of the cooling tower is connected to the bottom of the absorption tower through an air flow pipeline, and a booster fan is arranged on the air flow pipeline between the cooling tower and the absorption tower.

3. A carbon capture and storage system according to claim 2, characterized in that: The amine liquid circulation unit also includes a rich liquid pump and a lean liquid pump; the input end of the rich liquid pump is connected to the bottom of the absorption tower, and the output end is connected to the rich liquid inlet of the lean-rich liquid heat exchanger; the input end of the lean liquid pump is connected to the bottom of the desorption tower, and the output end is connected to the lean liquid inlet of the lean-rich liquid heat exchanger.

4. A carbon capture and storage system according to claim 2, characterized in that: A pressure reducing valve is arranged on the air flow pipeline between the air outlet and the compressor.

5. A carbon capture and storage system according to claim 2, characterized in that: A bubble distributor and a stirrer are arranged in the carbonization tank; the bubble distributor is connected to the output end of the compressor.

6. A carbon capture and storage system according to claim 2, characterized in that: The bottom of the filter is connected to the limestone slurry pool; the upper end of the filter is also provided with a gas outlet; the gas outlet is connected to the input end of the compressor through an air flow pipeline.

7. A carbon capture and storage method, characterized in that: Carbon capture and storage is performed using the carbon capture and storage system according to any one of claims 1 to 6, comprising the following steps: S1. When the waste gas needs to be decarbonized, the bypass valve is opened, and the waste gas is transported to the cooling tower through the flue gas conveying pipeline for seawater spraying. After cooling to 40-60°C, the waste gas flows into the absorption tower from the bottom of the absorption tower, contacts with the lean amine liquid sprayed in the absorption tower, and is absorbed by the lean amine liquid to form rich amine liquid and relatively pure gas. The relatively pure gas flows out from the gas outlet; S2, the formed rich amine liquid is heated to 95-110°C through the lean-rich liquid heat exchanger and then transported to the top of the desorption tower, sprayed from the top of the desorption tower to the bottom, and then heated and desorbed carbon dioxide gas after absorbing the steam heat generated by the reboiler to form lean amine liquid; S3, the formed lean amine liquid is cooled twice by the lean-rich liquid heat exchanger and the lean liquid cooler, and then transported to the top of the absorption tower. At the same time, the desorbed carbon dioxide gas is first cooled by the regeneration gas cooler, and then pressurized to 4-6 bar by the compressor and transported to the bottom of the carbonization tank. After that, based on the principle of enhanced rock weathering, under acidic conditions, the desorbed carbon dioxide gas reacts with the limestone slurry to generate soluble calcium bicarbonate. Part of the unreacted carbon dioxide gas is transported to the compressor from the gas outlet at the top of the carbonization tank, and is transported to the bottom of the carbonization tank again after compression; S4, start the slag pump, the calcium bicarbonate generated is transported to the filter together with the limestone slurry at the bottom of the carbonating tank for filtration, forming clarified liquid and limestone slag, and at the same time, limestone powder and seawater are transported in the limestone slurry pool to prepare limestone slurry, and the limestone slurry pump is started to transport limestone slurry to the top of the carbonating tank; S5. The clarified liquid formed in the filter is transported to the mixer, mixed with seawater in proportion to form a mixed liquid with a pH value of not less than 6, and the mixed liquid is discharged to the deep sea discharge area through the discharge port. At the same time, the limestone slurry residue in the filter is transported to the limestone slurry pool for preparing limestone slurry.

8. The carbon capture and storage method according to claim 7, characterized in that: In S2, the formed lean amine liquid is cooled twice, including cooling it to 60-70° C. through a lean-rich liquid heat exchanger and cooling it to 30-45° C. through a lean liquid cooler.

9. The carbon capture and storage method according to claim 7, characterized in that: In the S5, the ratio of clarified liquid to seawater is 1:(10-1000).

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