Carbon dioxide capture and energy storage coupling system and working method thereof

Abstract

The present application relates to the technical field of new energy, and provides a carbon dioxide capturing and energy storage coupling system and a working method thereof. The carbon dioxide capturing and energy storage coupling system comprises a crude carbon dioxide buffer tank, a first pre-cooler, a finished liquid carbon dioxide capturing unit, a carbon dioxide energy storage unit and a first control valve. The crude carbon dioxide buffer tank is connected with the first pre-cooler. The finished liquid carbon dioxide capturing unit and the carbon dioxide energy storage unit are both connected with the first pre-cooler. The finished liquid carbon dioxide capturing unit and the carbon dioxide energy storage unit are arranged in parallel. The first control valve is arranged between the carbon dioxide energy storage unit and the first pre-cooler. Through the structural arrangement, the finished liquid carbon dioxide capturing unit and the carbon dioxide energy storage unit are coupled, the crude carbon dioxide gas after carbon capture absorption and regeneration is stored in the crude carbon dioxide buffer tank, and the crude carbon dioxide gas after the pre-cooling effect of the first pre-cooler can not only realize the production of finished liquid carbon dioxide, but also can realize the energy storage of carbon dioxide. Therefore, the energy utilization efficiency and economic performance of the whole system can be improved.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and in particular to a carbon dioxide capture and energy storage coupling system and its working method. Background Technology

[0002] With in-depth research and technological advancements, carbon dioxide capture, utilization, and storage (CVC) technologies will gradually move from pilot demonstrations to commercial and large-scale applications. It is projected that by 2050, CVC technologies will play a greater role globally, offsetting 10%-20% of current global carbon emissions. Particularly in industries where emissions reductions are difficult to achieve through other means, such as power, steel, and cement, CVC technologies will become a key tool for achieving emission reduction targets.

[0003] Carbon dioxide (CO2) energy storage technology is an emerging physical energy storage method that uses CO2 as the working medium to store and release energy through compression and release. CO2 is non-toxic, non-flammable, readily available, and liquefies at room temperature. CO2 has favorable physical properties, possessing a suitable critical temperature and moderate critical pressure, and is easier to liquefy than air. CO2 energy storage technology is not limited by geographical conditions and can be deployed in various environments, giving it broad application potential globally.

[0004] Carbon capture systems are typically installed in industrial areas such as thermal power plants, cement plants, and coal kilns. Conventional carbon capture systems are all stand-alone systems. Stand-alone carbon capture systems involve significant overall investment, generate low revenue from the sale of the produced liquid carbon dioxide, and have low energy efficiency and poor economic viability. In contrast, conventional stand-alone carbon dioxide energy storage systems usually require a large-volume carbon dioxide storage facility on the low-pressure side, resulting in a large land area. Summary of the Invention

[0005] The present invention provides a carbon dioxide capture and energy storage coupling system to solve at least one of the above-mentioned technical problems.

[0006] According to a first aspect of the present invention, a carbon dioxide capture and energy storage coupled system is provided, comprising a crude carbon dioxide buffer tank, a first precooler, a finished liquid carbon dioxide capture unit, a carbon dioxide energy storage unit, and a first control valve.

[0007] The crude carbon dioxide buffer tank is connected to the first precooler, the finished liquid carbon dioxide capture unit and the carbon dioxide energy storage unit are both connected to the first precooler, the finished liquid carbon dioxide capture unit and the carbon dioxide energy storage unit are arranged in parallel, and the first control valve is provided between the carbon dioxide energy storage unit and the first precooler.

[0008] According to the present invention, a carbon dioxide capture and energy storage coupling system is provided, wherein the finished liquid carbon dioxide capture unit includes a first liquefaction compressor, a first desulfurization tower, a first drying adsorption tower, a distillation tower, a first refrigeration unit liquefaction unit, and a finished liquid carbon dioxide storage tank.

[0009] The first precooler is connected to the first liquefaction compressor. The first liquefaction compressor is connected to the first desulfurization tower. The first desulfurization tower is connected to the first drying adsorption tower. The first drying adsorption tower is connected to the distillation tower. The distillation tower is connected to the first refrigeration unit liquefaction unit. The first refrigeration unit liquefaction unit is connected to the finished liquid carbon dioxide storage tank.

[0010] According to the present invention, a carbon dioxide capture and energy storage coupling system is provided, wherein the carbon dioxide energy storage unit includes a primary compressor, a primary cooler, a secondary compressor, a secondary cooler, and a carbon dioxide energy storage tank.

[0011] The first precooler is connected to the first-stage compressor via the first control valve. The first-stage compressor is connected to the first-stage cooler. The first-stage cooler is connected to the second-stage compressor. The second-stage compressor is connected to the second-stage cooler. The second-stage cooler is connected to the carbon dioxide energy storage tank.

[0012] According to a carbon dioxide capture and energy storage coupling system provided by the present invention, the carbon dioxide capture and energy storage coupling system further includes a power generation unit, which is connected to the carbon dioxide energy storage tank.

[0013] According to the present invention, a carbon dioxide capture and energy storage coupling system is provided, wherein the power generation unit includes an evaporator, a primary heater, a primary expander, a secondary heater, and a secondary expander.

[0014] The carbon dioxide energy storage tank is connected to the evaporator. The evaporator is connected to the primary heater. The primary heater is connected to the primary expander. The primary expander is connected to the secondary heater. The secondary heater is connected to the secondary expander.

[0015] According to the present invention, a carbon dioxide capture and energy storage coupling system further includes a high-temperature storage tank, a low-temperature storage tank, and a radiator.

[0016] The heat exchange medium inlet of the primary cooler and the heat exchange medium inlet of the secondary cooler are both connected to the cryogenic storage tank. The heat exchange medium outlet of the primary cooler and the heat exchange medium outlet of the secondary cooler are both connected to the high-temperature storage tank. The heat exchange medium inlet of the primary heater and the heat exchange medium inlet of the secondary heater are both connected to the high-temperature storage tank. The heat exchange medium outlet of the primary heater and the heat exchange medium outlet of the secondary heater are both connected to the heat exchange medium inlet of the evaporator. The heat exchange medium outlet of the evaporator is connected to the cryogenic storage tank via the radiator.

[0017] According to a carbon dioxide capture and energy storage coupling system provided by the present invention, the carbon dioxide capture and energy storage coupling system further includes a second control valve. The secondary expander is connected to the crude carbon dioxide buffer tank through the second control valve.

[0018] According to the present invention, a carbon dioxide capture and energy storage coupling system further includes a third control valve, a second precooler, a second liquefaction compressor, a second sulfidation tower, a second drying adsorption tower, and a second refrigeration unit liquefaction unit.

[0019] The secondary expander is connected to the second precooler. The second precooler is connected to the second liquefaction compressor. The second liquefaction compressor is connected to the second sulfidation tower. The second sulfidation tower is connected to the second drying adsorption tower. The second drying adsorption tower is connected to the liquefaction unit of the second refrigeration unit. The liquefaction unit of the second refrigeration unit is connected to the finished liquid carbon dioxide storage tank via the third control valve.

[0020] According to a carbon dioxide capture and energy storage coupling system provided by the present invention, the carbon dioxide capture and energy storage coupling system further includes a fourth control valve. The fourth control valve is connected between the liquefier of the first refrigeration unit and the finished liquid carbon dioxide storage tank.

[0021] According to a second aspect of the present invention, a method for operating a carbon dioxide capture and storage coupled system is provided, comprising the following steps:

[0022] When simultaneous carbon dioxide capture and energy storage operations are required, open the first control valve.

[0023] The carbon dioxide capture and energy storage coupling system provided by this invention includes a crude carbon dioxide buffer tank, a first precooler, a finished liquid carbon dioxide capture unit, a carbon dioxide energy storage unit, and a first control valve. The inlet of the first precooler is connected to the outlet of the crude carbon dioxide buffer tank, and the outlet of the first precooler is connected to both the finished liquid carbon dioxide capture unit and the carbon dioxide energy storage unit. A first control valve is provided between the carbon dioxide energy storage unit and the outlet of the first precooler. The first control valve is used to control the connection state between the outlet of the first precooler and the carbon dioxide energy storage unit.

[0024] During operation, when it is necessary to simultaneously produce finished liquid carbon dioxide and store carbon dioxide energy, the first control valve is opened; when it is only necessary to produce finished liquid carbon dioxide, the first control valve is closed.

[0025] This structural arrangement couples the finished liquid carbon dioxide capture unit with the carbon dioxide energy storage unit. The crude carbon dioxide gas, after capture, absorption, and regeneration, enters a crude carbon dioxide buffer tank for storage and buffering. After pre-cooling by the first precooler, the crude carbon dioxide gas can not only enter the finished liquid carbon dioxide capture unit to produce finished liquid carbon dioxide, but also enter the carbon dioxide energy storage unit for carbon dioxide energy storage. This improves the overall energy efficiency and economic performance of the system. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the system structure of the carbon dioxide capture and energy storage coupling system provided by the present invention. Figure 1 ;

[0028] Figure 2 This is a schematic diagram of the system structure of the carbon dioxide capture and energy storage coupling system provided by the present invention. Figure 2 ;

[0029] Figure label:

[0030] 100. Crude carbon dioxide buffer tank; 200. First precooler; 310. First control valve; 320. Second control valve; 330. Third control valve; 340. Fourth control valve; 410. First liquefaction compressor; 420. First desulfurization tower; 430. First drying adsorption tower; 440. Distillation tower; 450. First refrigeration unit liquefaction unit; 460. Finished product liquid carbon dioxide storage tank; 510. First-stage compressor; 520. First-stage cooler; 530. Second... 540, Secondary compressor; 550, Carbon dioxide energy storage tank; 610, Evaporator; 620, Primary heater; 630, Primary expander; 640, Secondary heater; 650, Secondary expander; 710, High-temperature storage tank; 720, Low-temperature storage tank; 730, Radiator; 810, Secondary precooler; 820, Secondary liquefaction compressor; 830, Secondary sulfidation tower; 840, Secondary drying adsorption tower; 850, Secondary refrigeration unit liquefaction unit. Detailed Implementation

[0031] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0032] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0034] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] In the description of this specification, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate different embodiments or examples and features of different embodiments or examples described in this specification to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] The following is combined Figure 1 and Figure 2 This invention describes a carbon dioxide capture and storage coupled system and its operating method provided by embodiments of the present invention. It should be understood that the following description is merely an illustrative embodiment of the present invention and does not constitute any particular limitation on the present invention.

[0037] An embodiment of the first aspect of the present invention provides a carbon dioxide capture and energy storage coupled system, such as... Figure 1 and Figure 2 As shown, the carbon dioxide capture and energy storage coupling system includes a crude carbon dioxide buffer tank 100, a first precooler 200, a finished liquid carbon dioxide capture unit, a carbon dioxide energy storage unit, and a first control valve 310.

[0038] The crude carbon dioxide buffer tank 100 is connected to the first precooler 200. The finished liquid carbon dioxide capture unit and the carbon dioxide energy storage unit are both connected to the first precooler 200. The finished liquid carbon dioxide capture unit and the carbon dioxide energy storage unit are arranged in parallel. A first control valve 310 is installed between the carbon dioxide energy storage unit and the first precooler 200.

[0039] In other words, the carbon dioxide capture and energy storage coupling system provided by this invention includes a crude carbon dioxide buffer tank 100, a first precooler 200, a finished liquid carbon dioxide capture unit, a carbon dioxide energy storage unit, and a first control valve 310. The inlet of the first precooler 200 is connected to the outlet of the crude carbon dioxide buffer tank 100, and the outlet of the first precooler 200 is connected to both the finished liquid carbon dioxide capture unit and the carbon dioxide energy storage unit. A first control valve 310 is provided between the carbon dioxide energy storage unit and the outlet of the first precooler 200. The first control valve 310 is used to control the connection state between the outlet of the first precooler 200 and the carbon dioxide energy storage unit.

[0040] During operation, when it is necessary to simultaneously produce finished liquid carbon dioxide and store carbon dioxide energy, the first control valve 310 is opened; when it is only necessary to produce finished liquid carbon dioxide, the first control valve 310 is closed.

[0041] This structural arrangement couples the finished liquid carbon dioxide capture unit with the carbon dioxide energy storage unit. The crude carbon dioxide gas, after capture, absorption, and regeneration, enters the crude carbon dioxide buffer tank 100 for storage and buffering. After pre-cooling by the first precooler 200, the crude carbon dioxide gas can not only enter the finished liquid carbon dioxide capture unit to produce finished liquid carbon dioxide, but also enter the carbon dioxide energy storage unit for carbon dioxide energy storage. This improves the overall energy efficiency and economic performance of the system.

[0042] In one embodiment of the present invention, the finished liquid carbon dioxide capture unit includes a first liquefaction compressor 410, a first desulfurization tower 420, a first drying adsorption tower 430, a distillation tower 440, a first refrigeration unit liquefaction unit 450, and a finished liquid carbon dioxide storage tank 460.

[0043] The first precooler 200 is connected to the first liquefaction compressor 410. The first liquefaction compressor 410 is connected to the first desulfurization tower 420. The first desulfurization tower 420 is connected to the first drying adsorption tower 430. The first drying adsorption tower 430 is connected to the distillation tower 440. The distillation tower 440 is connected to the first refrigeration unit liquefaction unit 450. The first refrigeration unit liquefaction unit 450 is connected to the finished product liquid carbon dioxide storage tank 460.

[0044] Specifically, the crude carbon dioxide buffer tank 100 is used to receive crude carbon dioxide after adsorption and regeneration at the front end of the carbon capture process. The crude carbon dioxide in the buffer tank is mainly composed of a mixture of carbon dioxide, water vapor, sulfur dioxide, etc., and its temperature is 30-40℃. The carbon dioxide component usually accounts for 90%-95%. The first precooler 200 is used to regulate the temperature of the gas entering the first liquefaction compressor 410 and the carbon dioxide energy storage unit at any time. The gas temperature after precooling by the first precooler 200 is usually 25-35℃.

[0045] In the carbon capture process, the gas, after being pre-cooled by the first precooler 200, first enters the first liquefaction compressor 410 for compression and pressurization. Typically, the first liquefaction compressor 410 can compress the crude carbon dioxide gas to approximately 2.5 MPa. The first liquefaction compressor 410 can be a scroll compressor, piston compressor, screw compressor, or centrifugal compressor. The compressed and pressurized crude carbon dioxide gas then sequentially enters the first desulfurization tower 420 and the first drying and adsorption tower 430 for desulfurization and drying adsorption. The carbon dioxide after desulfurization and drying adsorption enters the distillation tower 440 for further purification. The distillation tower 440 is a novel composite packed tower, cylindrical in shape. A condenser is installed at the top of the distillation tower 440, two sections of stainless steel wire mesh structured packing are installed in the middle section, and a liquid storage area is located at the bottom. A reboiler is also installed at the bottom of the tower. The heat source for the reboiler can be a high-temperature heat source from industrial plants such as thermal power plant steam. After purification, the carbon dioxide enters the liquefaction unit 450 of the first refrigeration unit and is cooled to -20°C for liquefaction. Finally, the resulting liquid carbon dioxide is stored in the liquid carbon dioxide storage tank 460.

[0046] In one embodiment of the present invention, such as Figure 1 and Figure 2 As shown, the carbon dioxide energy storage unit includes a primary compressor 510, a primary cooler 520, a secondary compressor 530, a secondary cooler 540, and a carbon dioxide energy storage tank 550.

[0047] The first precooler 200 is connected to the first-stage compressor 510 via the first control valve 310. The first-stage compressor 510 is connected to the first-stage cooler 520. The first-stage cooler 520 is connected to the second-stage compressor 530. The second-stage compressor 530 is connected to the second-stage cooler 540. The second-stage cooler 540 is connected to the carbon dioxide energy storage tank 550.

[0048] In one embodiment of the present invention, the carbon dioxide capture and energy storage coupling system further includes a power generation unit connected to the carbon dioxide energy storage tank 550.

[0049] Furthermore, in one embodiment of the present invention, as Figure 1 and Figure 2 As shown, the power generation unit includes an evaporator 610, a primary heater 620, a primary expander 630, a secondary heater 640, and a secondary expander 650.

[0050] The carbon dioxide energy storage tank 550 is connected to the evaporator 610. The evaporator 610 is connected to the primary heater 620. The primary heater 620 is connected to the primary expander 630. The primary expander 630 is connected to the secondary heater 640. The secondary heater 640 is connected to the secondary expander 650.

[0051] The primary compressor 510 and the secondary compressor 530 are powered by renewable energy surplus, surplus electricity from thermal power generation, or off-peak electricity from the power grid. During carbon dioxide energy storage, the primary compressor 510 and the secondary compressor compress the low-pressure carbon dioxide to achieve a supercritical state with higher pressure and temperature. The primary cooler 520 and the secondary cooler 540 are used to cool the high-temperature carbon dioxide exiting the primary compressor 510 and the secondary compressor, respectively, and recover the heat of compression.

[0052] When storing carbon dioxide, the first control valve 310 needs to be opened. After being pre-cooled by the first precooler 200, the carbon dioxide can be diverted to the first-stage compressor 510 for compression, then enters the first-stage cooler 520 for cooling, then enters the second-stage compressor 530 for further compression, then enters the second-stage cooler 540 for cooling, and finally the high-pressure liquid carbon dioxide enters the carbon dioxide storage tank 550.

[0053] When high-pressure liquid carbon dioxide is needed for power generation, the high-pressure liquid carbon dioxide in the carbon dioxide energy storage tank 550 is introduced into the evaporator 610 to vaporize. After vaporization, the carbon dioxide sequentially enters the primary heater 620, the primary expander 630, the secondary heater 640, and the secondary expander 650. The primary expander 630 and the secondary expander 650 are connected to a generator for electrical output. During energy release, the reheated supercritical carbon dioxide enters the primary expander 630 and the secondary expander 650 to drive the impellers of these two expanders.

[0054] In one embodiment of the present invention, such as Figure 1 and Figure 2 As shown, the carbon dioxide capture and energy storage coupling system also includes a high-temperature storage tank 710, a low-temperature storage tank 720, and a radiator 730.

[0055] The heat exchange medium inlet of the primary cooler 520 and the heat exchange medium inlet of the secondary cooler 540 are both connected to the cryogenic storage tank 720. The heat exchange medium outlets of the primary cooler 520 and the secondary cooler 540 are both connected to the high-temperature storage tank 710. The heat exchange medium inlet of the primary heater 620 and the secondary heater 640 are both connected to the high-temperature storage tank 710. The heat exchange medium outlets of the primary heater 620 and the secondary heater 640 are both connected to the heat exchange medium inlet of the evaporator 610. The heat exchange medium outlet of the evaporator 610 is connected to the cryogenic storage tank 720 via a radiator 730. This structural arrangement allows for the full storage and utilization of compression heat, achieving staged heat utilization.

[0056] In one embodiment of the present invention, the carbon dioxide capture and storage coupling system further includes a second control valve 320. The secondary expander 650 is connected to the crude carbon dioxide buffer tank 100 via the second control valve 320.

[0057] Specifically, in the carbon dioxide energy storage process, the crude carbon dioxide gas (100-200 kPa, 40-50°C) after carbon capture, absorption and regeneration first enters the crude carbon dioxide buffer tank 100 for pressure stabilization, and then enters the first precooler 200 for precooling to a suitable temperature. Then, it is compressed to 7 MPa by the first control valve 310 sequentially entering the first-stage compressor 510 and the second-stage compressor 530. After passing through the first-stage cooler 520 and the second-stage cooler 540, it is cooled by the low-temperature heat storage medium flowing out of the low-temperature storage tank 720 and the heat generated by compression is transferred to the heat storage medium. After heat exchange, the heat storage medium is stored in the high-temperature heat storage tank. The cooled carbon dioxide becomes liquid and is stored in the carbon dioxide energy storage tank 550.

[0058] In the carbon dioxide power generation-liquefaction process, the carbon dioxide stored in the carbon dioxide energy storage tank 550 is preheated and vaporized in the evaporator 610 by absorbing the residual heat released from the thermal storage system. Then, the carbon dioxide is further heated to the inlet temperature of the primary heater 620 and the secondary heater 640, respectively. The heat for this process comes from the high-temperature heat stored in the thermal storage system. The high-temperature carbon dioxide then expands and performs work in the primary expander 630 and the secondary expander 650, driving the generator to output electrical energy. The carbon dioxide flowing out of the secondary expander 650 sequentially enters the finished liquid carbon dioxide capture unit when the second control valve 320 is open, thus completing the power generation process of the carbon dioxide energy storage system.

[0059] In the above system mode, the purity of carbon dioxide in the gas passing through the carbon dioxide energy storage unit and power generation unit is further improved, as some impurities have been screened out. This portion of carbon dioxide first enters the coarse carbon dioxide buffer pipe and the first precooler 200, then enters the first liquefaction compressor 410 where it is compressed to about 2.5 MPa. It then enters the first sulfidation tower and the first drying adsorption tower 430 to remove sulfur-containing gases, organic matter, and other impurities, and undergoes deep dehumidification via molecular sieves. The carbon dioxide further enters the distillation tower 440, where it is purified by distillation and flows out from the lower liquid storage area. The carbon dioxide processed in the distillation tower 440 is then cooled again to -20°C by the first refrigeration unit liquefaction unit 450 to achieve a certain subcooling state, meeting the requirements for the finished liquid carbon dioxide. Finally, it is filled into the finished liquid carbon dioxide storage tank 460 for loading, transportation, and storage.

[0060] In another embodiment of the present invention, the carbon dioxide capture and energy storage coupling system further includes a third control valve 330, a second precooler 810, a second liquefaction compressor 820, a second sulfidation tower 830, a second drying adsorption tower 840, and a second refrigeration unit liquefaction unit 850.

[0061] The secondary expander 650 is connected to the second precooler 810. The second precooler 810 is connected to the second liquefaction compressor 820. The second liquefaction compressor 820 is connected to the second vulcanization tower 830. The second vulcanization tower 830 is connected to the second drying adsorption tower 840. The second drying adsorption tower 840 is connected to the second refrigeration unit liquefaction unit 850. The second refrigeration unit liquefaction unit 850 is connected to the finished liquid carbon dioxide storage tank 460 through the third control valve 330.

[0062] Furthermore, in one embodiment of the present invention, the carbon dioxide capture and storage coupling system further includes a fourth control valve 340. The fourth control valve 340 is connected between the liquefier 450 of the first refrigeration unit and the finished liquid carbon dioxide storage tank 460.

[0063] In this system mode, the carbon dioxide output after being generated by the secondary expander 650 sequentially enters the independently configured second precooler 810, second liquefaction compressor 820, second sulfidation tower 830, second drying adsorption tower 840, and second refrigeration unit liquefaction unit 850, and then enters the finished liquid carbon dioxide storage tank 460 under the control of the third control valve 330. Furthermore, a fourth control valve 340 is installed between the finished liquid carbon dioxide storage tank 460 and the first refrigeration unit liquefaction unit 450 to control the connection between the two.

[0064] In this system mode, the carbon dioxide purification and liquefaction production process within the carbon dioxide capture unit and the carbon dioxide purification and liquefaction production process exiting the carbon dioxide energy storage unit do not interfere with each other. The two processes can run simultaneously, and the purification and liquefaction process at the back end of carbon capture is not affected when the carbon dioxide energy storage unit is in power generation operation. The system operation is more flexible and convenient, without involving extensive equipment start-up and shutdown or parameter adjustment and control.

[0065] As described above, the carbon dioxide capture and energy storage coupling system provided by this invention can improve energy efficiency. By combining carbon capture with carbon dioxide energy storage, it can directly utilize carbon dioxide as an energy storage medium during the carbon capture process, reducing the need for additional energy storage equipment and thus improving the overall system's energy efficiency. Simultaneously, it can reduce costs. This coupling system can reduce the investment and operating costs required for deploying separate carbon capture or energy storage systems. By sharing infrastructure and operating resources, economies of scale can be achieved, reducing unit costs. It also enhances system flexibility, providing greater operational flexibility. For example, when electricity demand is low, carbon dioxide can be captured and stored, while during peak demand periods, the stored carbon dioxide can be released for power generation or other uses, balancing the grid load. Furthermore, it improves the economics of both carbon capture and carbon dioxide energy storage, increasing energy storage revenue and promoting the widespread application of the technology.

[0066] A second aspect of the present invention provides a method for operating a carbon dioxide capture and storage coupled system, comprising the following steps:

[0067] When simultaneous carbon dioxide capture and energy storage operations are required, the first control valve 310 is opened.

[0068] When it is necessary to stop the carbon dioxide energy storage operation, close the first control valve 310.

[0069] Furthermore, in the working system of the independently set up power generation post-compression purification and liquefaction equipment, when carbon dioxide energy storage is required, the first control valve 310 and the third control valve 330 are opened, and the working state of the fourth control valve 340 is adjusted according to the specific operating requirements of the carbon dioxide capture unit; when carbon dioxide energy storage is required to stop, the first control valve 310 and the third control valve 330 are closed, and the working state of the fourth control valve 340 is adjusted according to the specific operating requirements of the carbon dioxide capture unit.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A carbon dioxide capture and energy storage coupled system, characterized in that, It includes a crude carbon dioxide buffer tank (100), a first precooler (200), a finished liquid carbon dioxide capture unit, a carbon dioxide energy storage unit, and a first control valve (310). The crude carbon dioxide buffer tank (100) is connected to the first precooler (200). The crude carbon dioxide buffer tank (100) is used to receive and store crude carbon dioxide gas after carbon capture, absorption and regeneration. The finished liquid carbon dioxide capture unit and the carbon dioxide energy storage unit are both connected to the first precooler (200). The finished liquid carbon dioxide capture unit and the carbon dioxide energy storage unit are arranged in parallel. The first control valve (310) is provided between the carbon dioxide energy storage unit and the first precooler (200). When it is necessary to simultaneously produce finished liquid carbon dioxide and store carbon dioxide, the first control valve (310) is opened; when it is only necessary to produce finished liquid carbon dioxide, the first control valve (310) is closed. The finished liquid carbon dioxide capture unit includes a first refrigeration unit liquefaction unit (450) and a finished liquid carbon dioxide storage tank (460), wherein the first refrigeration unit liquefaction unit (450) is connected to the finished liquid carbon dioxide storage tank (460). The carbon dioxide capture and energy storage coupling system also includes a power generation unit, which is connected to the carbon dioxide energy storage tank (550); The carbon dioxide energy storage unit includes a primary compressor (510), a primary cooler (520), a secondary compressor (530), a secondary cooler (540), and a carbon dioxide energy storage tank (550). The power generation unit includes an evaporator (610), a primary heater (620), a primary expander (630), a secondary heater (640), and a secondary expander (650). The carbon dioxide energy storage tank (550) is connected to the evaporator (610), the evaporator (610) is connected to the primary heater (620), the primary heater (620) is connected to the primary expander (630), the primary expander (630) is connected to the secondary heater (640), and the secondary heater (640) is connected to the secondary expander (650). The carbon dioxide capture and energy storage coupling system also includes a high-temperature storage tank (710), a low-temperature storage tank (720), and a radiator (730). The heat exchange medium inlet of the primary cooler (520) and the heat exchange medium inlet of the secondary cooler (540) are both connected to the low-temperature storage tank (720). The heat exchange medium outlet of the primary cooler (520) and the heat exchange medium outlet of the secondary cooler (540) are both connected to the high-temperature storage tank (710). The heat exchange medium inlet of the primary heater (620) and the heat exchange medium inlet of the secondary heater (640) are both connected to the high-temperature storage tank (710). The heat exchange medium outlet of the primary heater (620) and the heat exchange medium outlet of the secondary heater (640) are both connected to the heat exchange medium inlet of the evaporator (610). The heat exchange medium outlet of the evaporator (610) is connected to the low-temperature storage tank (720) through the radiator (730). The carbon dioxide capture and energy storage coupling system further includes a second control valve (320), through which the secondary expander (650) is connected to the crude carbon dioxide buffer tank (100); or, the carbon dioxide capture and energy storage coupling system further includes a third control valve (330). The secondary expander (650) is connected to the second precooler (810), the second precooler (810) is connected to the second liquefaction compressor (820), the second liquefaction compressor (820) is connected to the second sulfidation tower (830), the second sulfidation tower (830) is connected to the second drying adsorption tower (840), the second drying adsorption tower (840) is connected to the second refrigeration unit liquefaction unit (850), and the second refrigeration unit liquefaction unit (850) is connected to the finished liquid carbon dioxide storage tank (460) through the third control valve (330). The carbon dioxide capture and energy storage coupling system also includes a fourth control valve (340), which is connected between the first refrigeration unit liquefaction unit (450) and the finished liquid carbon dioxide storage tank (460).

2. The carbon dioxide capture and energy storage coupled system according to claim 1, characterized in that, The finished liquid carbon dioxide capture unit also includes a first liquefaction compressor (410), a first desulfurization tower (420), a first drying adsorption tower (430), and a distillation tower (440). The first precooler (200) is connected to the first liquefaction compressor (410), the first liquefaction compressor (410) is connected to the first desulfurization tower (420), the first desulfurization tower (420) is connected to the first drying adsorption tower (430), the first drying adsorption tower (430) is connected to the distillation tower (440), and the distillation tower (440) is connected to the first refrigeration unit liquefaction unit (450).

3. The carbon dioxide capture and energy storage coupled system according to claim 2, characterized in that, The first precooler (200) is connected to the first-stage compressor (510) via the first control valve (310). The first-stage compressor (510) is connected to the first-stage cooler (520). The first-stage cooler (520) is connected to the second-stage compressor (530). The second-stage compressor (530) is connected to the second-stage cooler (540). The second-stage cooler (540) is connected to the carbon dioxide energy storage tank (550).

4. A method for operating the carbon dioxide capture and energy storage coupled system according to any one of claims 1 to 3, characterized in that, Includes the following steps: When carbon dioxide capture and energy storage operations need to be performed simultaneously, open the first control valve (310).

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