Energy storage power generation system enabling carbon dioxide underground sequestration and method of operating the same

Abstract

The application discloses a storage energy power generation system capable of realizing carbon dioxide underground storage and an operation method thereof. The storage energy power generation system capable of realizing carbon dioxide underground storage comprises a high-pressure carbon dioxide storage underground storage and a normal-pressure and normal-temperature carbon dioxide storage gas storage. In the storage energy state, carbon dioxide is stored in the underground storage. In the energy release state, the underground storage releases part of the carbon dioxide and stores the carbon dioxide in the gas storage. The underground storage serves as the carbon dioxide storage and the high-pressure storage tank for storing energy of compressed carbon dioxide, and thus saves the construction cost. When the storage energy system is decommissioned, the underground storage can continue to store carbon dioxide for a long time. The heat storage assembly of the application recycles the compression heat generated in the compression process of carbon dioxide and uses the compression heat for the expansion process of carbon dioxide, so that the energy recycling is realized and the system energy consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide sequestration and energy storage power generation technology, and in particular to an energy storage power generation system capable of underground carbon dioxide sequestration and its operation method. Background Technology

[0002] Carbon dioxide sequestration involves storing carbon dioxide in specific natural or artificial reservoirs using physical, chemical, and biochemical methods to preserve it long-term. Carbon dioxide sequestration is the most critical condition for the realization of carbon dioxide capture, utilization, and storage (CCUS) technology. Geological carbon dioxide sequestration technology is still in the research and demonstration stage. Artificial container sequestration offers flexibility and is suitable for specific scenarios, but its high cost makes large-scale application difficult. Compressed carbon dioxide energy storage technology is an energy storage system capable of large-capacity and long-term electrical energy storage. It stores excess electricity by compressing atmospheric carbon dioxide gas to high pressure and liquefying it using a compressor. When electricity is needed, the high-pressure liquid carbon dioxide is vaporized, released, and expands to generate electricity. Compressed carbon dioxide energy storage devices require large-volume high-pressure liquid storage tanks and ultra-large-volume atmospheric pressure gas storage tanks to store carbon dioxide. However, artificial high-pressure liquid storage tanks are expensive and have a short service life, making them unusable for carbon dioxide sequestration after decommissioning. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention propose an energy storage power generation system and its operation method that enables underground carbon dioxide storage.

[0005] On the one hand, this invention proposes an energy storage and power generation system capable of underground carbon dioxide sequestration, comprising:

[0006] An underground storage facility for storing carbon dioxide;

[0007] A gas storage facility for storing carbon dioxide at normal temperature and pressure;

[0008] A compression assembly is connected to the outlet end of the gas storage tank, and the compression assembly is used to compress and pressurize the carbon dioxide in the gas storage tank before inputting it into the underground storage tank.

[0009] An expansion assembly is connected to the inlet end of the gas storage facility. The expansion assembly is used to expand and depressurize the carbon dioxide in the underground storage facility before inputting it into the gas storage facility.

[0010] A thermal storage component, wherein the thermal storage component is connected to the compression component and to the expansion component via heat exchange connections;

[0011] A pressurizing component is connected between the outlet end of the compression component and the inlet end of the expansion component. The pressurizing component is used to liquefy and pressurize the carbon dioxide output from the compression component and input it into the underground storage tank, and to liquefy and pressurize the carbon dioxide output from the underground storage tank and input it into the expansion component.

[0012] In some embodiments, the compression assembly includes a plurality of compression modules arranged in series, each compression module including a compressor and a heat exchanger disposed at the outlet end of the compressor.

[0013] In some embodiments, the expansion assembly includes a plurality of expansion modules arranged in series, each expansion module including an expander and a reheater disposed at the inlet end of the expander.

[0014] In some embodiments, the thermal storage assembly includes a cold tank containing a low-temperature heat transfer medium and a hot tank containing a high-temperature heat transfer medium. The hot tank is connected between the cold-side outlet of the heat exchanger and the hot-side inlet of the reheater, and the cold tank is connected between the cold-side inlet of the heat exchanger and the hot-side outlet of the reheater.

[0015] In some embodiments, the booster assembly includes:

[0016] A first condenser and a first booster pump are connected between the outlet end of the compression component and the inlet end of the underground storage tank. Carbon dioxide flowing out from the outlet end of the compression component is condensed by the first condenser and boosted by the first booster pump before being input into the underground storage tank.

[0017] A second condenser and a second booster pump are connected between the outlet end of the underground storage tank and the inlet end of the expansion component. Carbon dioxide flowing out of the underground storage tank is condensed by the second condenser and pressurized by the second booster pump before being transported to the expansion component.

[0018] In some embodiments, the pressurization assembly further includes a regenerator, the hot side of which is carbon dioxide flowing from the underground storage tank, and the cold side of which is carbon dioxide that has been condensed by the second condenser and pressurized by the second booster pump.

[0019] In some embodiments, the gas storage facility consists of multiple interconnected air-supported membrane chambers or gas holders.

[0020] In some embodiments, the underground storage facility is a salt cavern or a mine shaft.

[0021] In some embodiments, the pressure of the underground storage facility is above 7 MPa.

[0022] On the other hand, this invention proposes an operation method for an energy storage power generation system capable of underground carbon dioxide storage. The energy storage power generation system capable of underground carbon dioxide storage according to this invention includes the following processes:

[0023] Energy storage stage: The compression assembly is started to compress the carbon dioxide in the gas storage tank step by step to a pressure no lower than that of the first condenser. The compressed carbon dioxide is condensed by the first condenser and pressurized by the first booster pump before being transported to the underground storage tank for storage. At the same time, the low-temperature heat transfer medium in the cold tank flows through the heat exchanger to exchange heat with the carbon dioxide to recover the heat of compression until the gas storage tank is vented.

[0024] Energy release stage: The carbon dioxide flowing out from the underground storage tank is condensed by the second condenser, pressurized by the second booster pump, and reheated by the regenerator before being transported to the expansion component. The carbon dioxide, which has expanded to normal temperature and pressure, enters the gas storage tank for storage. At the same time, the high-temperature heat transfer medium in the hot tank flows through the reheater to exchange heat with the carbon dioxide to heat the carbon dioxide until the gas storage tank is full.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The underground storage facility of the present invention serves as both a carbon dioxide storage tank and a high-pressure storage tank for compressed carbon dioxide energy storage, achieving two goals at once, saving construction costs, and allowing the underground storage facility to continue storing carbon dioxide for a long period of time after the energy storage system is decommissioned.

[0027] The thermal storage component of this invention recovers the heat generated during the compression process of carbon dioxide and uses it for the expansion process of carbon dioxide, thereby realizing energy recovery and utilization and reducing system energy consumption. Attached Figure Description

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0029] Figure 1 This is a schematic diagram of the energy storage and power generation system of the present invention that enables underground carbon dioxide storage;

[0030] Explanation of reference numerals in the attached figures:

[0031] Underground sealed warehouse 1;

[0032] Gas storage facility 2;

[0033] Compression assembly 3, first compressor 31, second compressor 32, third compressor 33, first heat exchanger 34, second heat exchanger 35, third heat exchanger 36;

[0034] Thermal storage component 4, first hot tank 41, first cold tank 42, second hot tank 43, second cold tank 44, third hot tank 45, third cold tank 46;

[0035] Expansion assembly 5, first expander 51, second expander 52, third expander 53, first reheater 54, second reheater 55, third reheater 56;

[0036] The booster assembly 6 includes a first condenser 61, a first booster pump 62, a second condenser 63, a second booster pump 64, and a regenerator 65. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0038] The following description, with reference to the accompanying drawings, describes an energy storage and power generation system capable of underground carbon dioxide storage and its operation method, according to an embodiment of the present invention.

[0039] like Figure 1 As shown, the energy storage and power generation system of the present invention, which enables underground carbon dioxide storage, includes an underground storage tank 1, a gas storage tank 2, a compression assembly 3, an expansion assembly 5, a heat storage assembly 4, and a pressurization assembly 6.

[0040] Underground storage facility 1 is used for carbon dioxide storage, with a preferred pressure of 10 MPa or higher. Due to the high underground temperature, the carbon dioxide in underground storage facility 1 is in a supercritical state. Underground storage facility 1 is constructed using salt caverns or mine tunnels, which are left after artificial mining. After selecting salt caverns or mine tunnels with suitable volume and condition, and carrying out necessary modifications and testing, they can be used for carbon dioxide storage.

[0041] Gas storage facility 2 is used to store gaseous carbon dioxide at normal temperature and pressure. It consists of multiple interconnected gas-supported membrane chambers or gas holders. The gas-supported membrane chambers are scalable structures, and the gas holders are cylindrical structures with their top covers movable up and down to adjust their volume. It is understood that the gas-supported membrane chambers or gas holders can also be other structures.

[0042] The compression assembly 3 is connected to the outlet end of the gas storage tank 2. The compression assembly 3 is used to compress and pressurize the carbon dioxide in the gas storage tank 2 and then input it into the underground storage tank 1. The compression assembly 3 includes multiple compression modules connected in series. Each compression module includes a compressor and a heat exchanger located at the outlet end of the compressor.

[0043] Specifically, multiple compression modules are connected in series to form a compression assembly 3. Each compression module includes a compressor and a heat exchanger. In one compression module, the heat exchanger is located at the compressor's outlet to recover the heat of compression generated during the compression of carbon dioxide. The compression assembly 3 uses multiple compression modules to perform multi-stage compression of the carbon dioxide at the outlet of the gas storage tank 2. The compressed carbon dioxide from the compression assembly 3 is then condensed and pressurized by the booster assembly 6 before being input into the underground storage tank 1 for storage. During this process, the heat of compression is simultaneously recovered and transferred to the heat storage assembly 4, reducing heat energy waste. Figure 1 As shown, the compression assembly 3 includes three compression modules arranged in series: a first compression module, a second compression module, and a third compression module. The first compression module includes a first compressor 31 and a first heat exchanger 34, with the first heat exchanger 34 located at the outlet end of the first compressor 31 and the inlet end of the first heat exchanger 31 connected to the outlet end of the gas storage tank 2. The second compression module includes a second compressor 32 and a second heat exchanger 35, with the second heat exchanger 35 located at the outlet end of the second compressor 32. The third compression module includes a third compressor 33 and a third heat exchanger 36, with the third heat exchanger 36 located at the outlet end of the third compressor 33 and the hot-side outlet end of the third heat exchanger 36 connected to the inlet end 61 of the first condenser.

[0044] The expansion assembly 5 is connected to the inlet end of the gas storage tank 2. The expansion assembly 5 is used to expand and depressurize the carbon dioxide in the underground storage tank 1 and then input it into the gas storage tank 2. The expansion assembly 5 includes multiple expansion modules arranged in series. The expansion module includes an expander and a reheater located at the inlet end of the expander.

[0045] Specifically, multiple expansion modules are connected in series to form expansion assembly 5. Each expansion module includes an expander and a reheater. In one expansion module, the reheater is located at the inlet of the expander. Carbon dioxide first flows through the reheater to be heated, and then flows to the expander to expand and perform work. Expansion assembly 5 utilizes multiple expansion modules to perform multi-stage expansion of the carbon dioxide flowing out of underground storage tank 1, ultimately expanding the carbon dioxide to ambient temperature and pressure and storing it in gas storage tank 2. Figure 1 As shown, the expansion assembly 5 includes three expansion modules connected in series: a first expansion module, a second expansion module, and a third expansion module. The first expansion module includes a first expander 51 and a first reheater 54, with the first reheater 54 located at the inlet end of the first expander 51. The second expansion module includes a second expander 52 and a second reheater 55, with the second reheater 55 located at the inlet end of the second expander 52. The third expansion module includes a third expander 53 and a third reheater 56, with the third reheater 56 located at the inlet end of the third expander 53. The outlet end of the third expander 53 is connected to the inlet end of the gas storage tank 2. It can be understood that when the expander is connected to a generator, the expander can utilize the expansion of carbon dioxide to perform work on the generator, thereby generating electricity.

[0046] The heat storage component 4 is used to store heat from the heat exchanger and release heat to the reheater. The heat storage component 4 is connected to the compression component 3 and the expansion component 5 through heat exchange connections. The heat storage component 4 includes a cold tank containing a low-temperature heat transfer medium and a hot tank containing a high-temperature heat transfer medium. The hot tank is connected between the cold side outlet of the heat exchanger and the hot side inlet of the reheater, and the cold tank is connected between the cold side inlet of the heat exchanger and the hot side outlet of the reheater.

[0047] Specifically, the heat storage component 4 is configured in a one-to-one correspondence with the heat exchanger and the reheater. The heat storage component 4 includes a cold tank and a hot tank. The cold tank is used to store the low-temperature heat transfer medium, and the hot tank is used to store the high-temperature heat transfer medium. The hot tank is connected between the cold side outlet end of the heat exchanger and the hot side inlet end of the reheater, and the cold tank is connected between the cold side inlet end of the heat exchanger and the hot side outlet end of the reheater. In the heat exchanger, the hot-side medium is compressed carbon dioxide, and the cold-side medium is a low-temperature heat transfer medium. During operation, the low-temperature heat transfer medium flowing from the cold tank flows from the cold-side inlet of the heat exchanger to the cold side of the heat exchanger, exchanging heat with the carbon dioxide on the hot side. After being heated to a high-temperature heat transfer medium, it flows out from the cold-side outlet of the heat exchanger and enters the hot tank for storage, completing heat storage. In the reheater, the hot-side medium is a high-temperature heat transfer medium stored in the hot tank, and the cold-side medium is carbon dioxide. During operation, the high-temperature heat transfer medium flowing from the hot tank flows from the hot-side inlet of the reheater to the hot side of the reheater, exchanging heat with the carbon dioxide on the cold side. The high-temperature heat transfer medium cools down to a low-temperature heat transfer medium and flows out from the hot-side outlet of the reheater, entering the cold tank for storage. The carbon dioxide is heated and then enters the expander to expand and do work. The entire heat exchange process realizes heat recovery and utilization, reducing energy consumption. Figure 1 As shown, there are three sets of thermal storage components: a first thermal storage component, a second thermal storage component, and a third thermal storage component. The first thermal storage component includes a first hot tank 41 and a first cold tank 42. The first hot tank 41 is connected between the cold-side outlet of the first heat exchanger 34 and the hot-side inlet of the third reheater 56, and the first cold tank 42 is connected between the cold-side inlet of the first heat exchanger 34 and the hot-side outlet of the third reheater 56. The second thermal storage component includes a second hot tank 43 and a second cold tank 44. The second hot tank 43 is connected... The second heat exchanger 35 is located between the cold-side outlet and the hot-side inlet of the second reheater 55, and the second cold tank 44 is connected between the cold-side inlet and the hot-side outlet of the second heat exchanger 35; the third heat storage assembly includes a third hot tank 45 and a third cold tank 46, the third hot tank 45 is connected between the cold-side outlet and the hot-side inlet of the first reheater 54, and the third cold tank 46 is connected between the cold-side inlet and the hot-side outlet of the first reheater 54.

[0048] The pressurization assembly 6 is connected between the outlet end of the compression assembly 3 and the inlet end of the expansion assembly 5. The pressurization assembly 6 is used to liquefy and pressurize the carbon dioxide output from the compression assembly 3 before inputting it into the underground storage tank 1, and to liquefy and pressurize the carbon dioxide output from the underground storage tank 1 before inputting it into the expansion assembly 5. The pressurization assembly 6 includes a first condenser 61, a first booster pump 62, a second condenser 63, and a second booster pump 64. Figure 1 As shown, the first condenser 61 and the first booster pump 62 are connected and arranged between the outlet end of the compression assembly 3 and the inlet end of the underground storage tank 1. The carbon dioxide after being compressed in multiple stages by the compression assembly 3 is not lower than the condensation pressure of the first condenser 61. The carbon dioxide flowing out from the outlet end of the compression assembly 3 is condensed and liquefied by the first condenser 61 and pressurized by the first booster pump 62 before being input into the underground storage tank 1. The second condenser 63 and the second booster pump 64 are connected and arranged between the outlet end of the underground storage tank 1 and the inlet end of the expansion assembly 5. The carbon dioxide flowing out from the underground storage tank 1 is condensed and liquefied by the second condenser 63 and pressurized by the second booster pump 64 before being transported to the expansion assembly 5.

[0049] In some embodiments, the pressurization assembly 6 further includes a regenerator 65. The hot side of the regenerator 65 contains carbon dioxide flowing out from the underground storage tank 1, and the cold side contains carbon dioxide that has been condensed by the second condenser 63 and pressurized by the second booster pump 64. Specifically, the hot-side inlet of the regenerator 65 is connected to the outlet of the underground storage tank 1, and the cold-side inlet of the regenerator 65 is connected to the outlet of the second booster pump 64. The carbon dioxide flowing out from the underground storage tank 1 flows into the regenerator 65 from the hot-side inlet and exchanges heat with the carbon dioxide pressurized by the second booster pump 64 flowing into the regenerator 65 from the cold-side inlet, thereby heating the carbon dioxide pressurized by the second booster pump 64. The hot-side outlet of the regenerator 65 is connected to the inlet of the second condenser 63, and the outlet of the second condenser 63 is connected to the inlet of the second booster pump 64. Carbon dioxide flowing from the hot-side outlet of the regenerator 65 flows sequentially through the second condenser 63 for condensation and liquefaction, and then is pressurized by the second booster pump 64. It then enters the regenerator 65 again from the cold-side inlet for reheating. The carbon dioxide flowing from the cold-side outlet of the regenerator 65 enters the cold side of the first reheater 54. The regenerator 65 utilizes the thermal energy of the carbon dioxide in the underground storage tank 1 to heat the condensed and pressurized carbon dioxide, thus reducing energy consumption.

[0050] The system of this invention can receive carbon dioxide from a carbon dioxide capture device, fill it into an underground storage tank 1, and then use it for energy storage and power generation. Assuming a 100MW-class energy storage power station uses an underground salt cavern as the storage tank 1, with a volume of 100,000 cubic meters, a pressure of 12 MPa, and a temperature of approximately 45°C, it can store approximately 60,000 tons of carbon dioxide. Therefore, this invention has two uses: carbon dioxide storage and energy storage for power generation, offering excellent comprehensive benefits.

[0051] An operation method for an energy storage and power generation system capable of underground carbon dioxide storage, utilizing the energy storage and power generation system capable of underground carbon dioxide storage of the present invention, includes the following processes:

[0052] Energy storage stage: The compression assembly 3 is started to compress the carbon dioxide in the gas storage tank 2 step by step to a condensation pressure not lower than that of the first condenser 61. The compressed carbon dioxide is condensed by the first condenser 61 and pressurized by the first booster pump 62 in sequence and then transported to the underground storage tank 1 for storage. The preferred pressure is 10-15MPa. At the same time, the low temperature heat transfer medium in the cold tank flows through the heat exchanger to exchange heat with the carbon dioxide to recover the heat of compression until the gas storage tank 2 is vented.

[0053] Energy release stage: The carbon dioxide flowing out from the underground storage tank 1 is condensed by the second condenser 63, pressurized by the second booster pump 64, and reheated by the regenerator 65 before being transported to the expansion component 5. The carbon dioxide, which has expanded to a normal temperature and pressure state, enters the gas storage tank 2 for storage. At the same time, the high-temperature heat transfer medium in the hot tank flows through the reheater to exchange heat with the carbon dioxide to heat the carbon dioxide until the gas storage tank 2 is full.

[0054] Specifically, initially, the underground storage tank 1 is filled with high-pressure carbon dioxide, preferably at a pressure of 7-8 MPa, while the gas storage tank 2 is also full. The energy storage phase includes the simultaneous transfer of carbon dioxide from the gas storage tank 2 to the underground storage tank 1 and a compression energy storage process. During this phase, the compression assembly 3 is activated to progressively compress the carbon dioxide in the gas storage tank 2 to a pressure not lower than the condensing pressure of the first condenser 61, and then delivers it to the pressurization assembly 6. During this process, the heat of compression is recovered using a heat exchanger, and the low-temperature heat transfer medium in the cold tank flows through the heat exchanger to exchange heat with the carbon dioxide to recover the heat of compression. The carbon dioxide delivered to the pressurization assembly 6 is condensed and liquefied by the first condenser 61 and pressurized by the first booster pump 62 before entering the underground storage tank 1 for storage until the gas storage tank 2 is vented. This process achieves both carbon dioxide sealing and compression energy storage.

[0055] The energy release phase includes the simultaneous transfer of carbon dioxide from the underground storage tank 1 to the gas storage tank 2 and the expansion energy release process. The carbon dioxide flowing out of the underground storage tank 1 is condensed and liquefied by the second condenser 63, pressurized by the second booster pump 64, and reheated by the regenerator 65 before being transported to the expansion assembly 5, preferably at a pressure of 15 MPa or higher. After being heated by the reheater, it is fed into the expander to do work, and finally expands to a normal temperature and pressure state. The carbon dioxide is then stored in the gas storage tank 2 until the gas storage tank 2 is full. This process realizes the release of carbon dioxide and the expansion energy release.

[0056] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms may refer to different embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0057] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0058] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An energy storage power generation system that enables carbon dioxide sequestration underground, characterized by, The system comprises: a subterranean storage for storing carbon dioxide, the subterranean storage being a salt cavern or a mine; a gas storage for storing gaseous carbon dioxide at normal temperature and pressure; a compression assembly connected to an outlet end of the gas storage, the compression assembly being configured to compress and pressurize the carbon dioxide in the gas storage and then input the carbon dioxide into the subterranean storage; an expansion assembly connected to an inlet end of the gas storage, the expansion assembly being configured to expand and depressurize the carbon dioxide in the subterranean storage and then input the carbon dioxide into the gas storage; a heat storage assembly, the heat storage assembly being in heat exchange connection with the compression assembly and the expansion assembly; a pressurization assembly connected between an outlet end of the compression assembly and an inlet end of the expansion assembly, the pressurization assembly being configured to liquefy and pressurize the carbon dioxide output by the compression assembly and then input the carbon dioxide into the subterranean storage, and liquefy and pressurize the carbon dioxide output by the subterranean storage and then input the carbon dioxide into the expansion assembly, the pressurization assembly comprising: a first condenser and a first pressurization pump connected between the outlet end of the compression assembly and an inlet end of the subterranean storage, a second condenser and a second pressurization pump connected between an outlet end of the subterranean storage and the inlet end of the expansion assembly, and a heat exchanger, a hot side of the heat exchanger being the carbon dioxide flowing out of the subterranean storage, and a cold side of the heat exchanger being the carbon dioxide condensed by the second condenser and pressurized by the second pressurization pump in sequence.

2. The system of claim 1, wherein, The compression assembly comprises a plurality of compression modules connected in series, each compression module comprising a compressor and a heat exchanger connected to an outlet end of the compressor.

3. The system of claim 2, wherein, The expansion assembly comprises a plurality of expansion modules connected in series, each expansion module comprising an expander and a reheater connected to an inlet end of the expander.

4. The system of claim 3, wherein, The heat storage assembly comprises a cold tank containing a low-temperature heat transfer medium and a hot tank containing a high-temperature heat transfer medium, the hot tank being connected between an outlet end of the cold side of the heat exchanger and an inlet end of the hot side of the reheater, and the cold tank being connected between an inlet end of the cold side of the heat exchanger and an outlet end of the hot side of the reheater.

5. The system of claim 1, wherein, The carbon dioxide flowing out of the outlet end of the compression assembly is condensed by the first condenser and pressurized by the first pressurization pump in sequence and then input into the subterranean storage. The carbon dioxide flowing out of the subterranean storage is condensed by the second condenser and pressurized by the second pressurization pump in sequence and then input into the expansion assembly.

6. The system of claim 1, wherein, The gas storage is composed of a plurality of gas film warehouses or gas tanks connected in series.

7. The system of claim 1, wherein, The pressure of the subterranean storage is above 7 MPa.

8. A method of operating an energy storage power generation system that enables carbon dioxide sequestration underground, characterized by, The system according to any one of claims 1-7 is used, The system comprises the following processes: a storage phase: start the compression assembly to compress the carbon dioxide in the gas storage to a condensing pressure of the first condenser or higher, the compressed carbon dioxide is condensed by the first condenser and pressurized by the first pressurization pump in sequence and then input into the subterranean storage for storage, at the same time, the low-temperature heat transfer medium in the cold tank flows through the heat exchanger to exchange heat with the carbon dioxide to recover the compression heat, until the gas storage is empty; The energy releasing stage: the carbon dioxide flowing out of the underground storage is condensed by the second condenser, pressurized by the second booster pump and heat-exchanged by the regenerator, and then is delivered to the expansion assembly, the carbon dioxide expanded to the normal temperature and pressure enters the gas storage, and the high-temperature heat transfer medium in the hot tank flows through the reheater to exchange heat with the carbon dioxide to heat the carbon dioxide until the gas storage is full.

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