Carbon dioxide energy storage system and control method thereof
By employing a steam drum evaporator and a flow control device in the carbon dioxide energy storage system, the problems of equipment damage and temperature instability during the liquid carbon dioxide transportation process have been solved, achieving efficient and stable energy release and power generation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-22
- Publication Date
- 2026-03-13
AI Technical Summary
Existing carbon dioxide energy storage systems suffer from excessive power consumption and equipment stability issues during the energy release phase. In particular, liquid carbon dioxide is prone to vaporization during transportation, leading to pump cavitation damage, and the output temperature of the evaporation unit is not easy to control stably.
A steam drum evaporator is used to replace the traditional evaporator. Liquid carbon dioxide is transported by gravity and the flow rate is controlled by a flow control device, avoiding the use of a delivery pump. Combined with a heating structure, the gas temperature is stably controlled.
It improves system efficiency, reduces plant power consumption, reduces the risk of equipment damage, stabilizes gas temperature, and enhances system operational stability.
Smart Images
Figure CN121663579A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of carbon dioxide energy storage technology, and in particular to a carbon dioxide energy storage system and its control method. Background Technology
[0002] Currently, energy storage technology based on carbon dioxide gas-liquid phase change cycle has gradually attracted widespread attention. During periods of low electricity demand, excess electricity or clean energy is used to compress and condense gaseous carbon dioxide at room temperature and pressure into liquid carbon dioxide, which is then stored in a liquid storage unit. The heat energy generated during the compression process is stored. During periods of high electricity demand, the stored heat energy is used to heat the liquid carbon dioxide back to a gaseous state. The gaseous carbon dioxide drives a turbine to generate electricity, and the gaseous carbon dioxide after doing work is returned to the gas storage unit for recycling. It has advantages such as simple structure, flexible layout, and high energy storage efficiency.
[0003] In existing carbon dioxide energy storage systems, during the energy release phase, the process of transferring liquid carbon dioxide from the storage unit to the evaporation unit is primarily powered by a transfer pump to overcome pipeline resistance and increase head. This not only leads to excessive power consumption during the energy release process, reducing the efficiency of the carbon dioxide energy storage system, but also, under actual operating conditions, the easy vaporization of liquid carbon dioxide can cause cavitation in the transfer pump, damaging the equipment and adversely affecting the stability of the system. Furthermore, the design of carbon dioxide energy storage systems requires the temperature (superheat) of the carbon dioxide gas formed by evaporation and vaporization in the evaporation unit and transported to the energy release unit to be constant or within a certain range. However, the temperature of the carbon dioxide gas output from existing evaporation units is difficult to control stably, frequently deviating from rated operating conditions, which is detrimental to the stable operation of the energy storage system. Summary of the Invention
[0004] In view of the problems existing in the prior art, the present invention provides a carbon dioxide energy storage system and its control method to solve the problems of how to reduce plant power consumption to improve the efficiency of the carbon dioxide energy storage system and how to improve the operational stability of the carbon dioxide energy storage system.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: A first aspect of the present invention is to provide a carbon dioxide energy storage system, comprising a gas storage unit, an energy storage unit, a condensation unit, a liquid storage unit, an evaporation unit, and an energy release unit connected in a closed loop in sequence. The evaporation unit includes a flow control device and a steam drum evaporation device. The input end of the flow control device is connected to the output end of the liquid storage unit, the output end of the flow control device is connected to the liquid phase inlet of the steam drum evaporation device, and the gas phase outlet of the steam drum evaporation device is connected to the input end of the energy release unit. The liquid inlet of the steam drum evaporator is configured to be lower than the output end of the liquid storage unit, so that the liquid carbon dioxide stored in the liquid storage unit can be automatically transported to the steam drum evaporator by the flow control device based on gravity; the steam drum evaporator is used to evaporate and vaporize the liquid carbon dioxide to form carbon dioxide gas, and transport the carbon dioxide gas to the energy release unit. The flow control device is configured to control the flow rate of liquid carbon dioxide supplied to the steam drum evaporator, thereby controlling the temperature of the carbon dioxide gas supplied by the steam drum evaporator to the energy release unit.
[0006] In a specific embodiment, the flow control device includes a first liquid phase pipeline and a second liquid phase pipeline connected in parallel between the output end of the liquid storage unit and the liquid phase inlet of the steam drum evaporator. A first valve is provided on the first liquid phase pipeline, and a second valve is provided on the second liquid phase pipeline. The first valve is a gate valve, and the second valve is a flow regulating valve.
[0007] In the specific design, a third valve is provided on both sides of the second valve on the second liquid phase pipeline, and the third valve is a gate valve.
[0008] In a specific embodiment, the steam drum evaporation device includes a steam drum, a downcomer, a lower header, and a riser connected in sequence. The liquid phase inlet is located on one side of the steam drum and connected to the output end of the flow control device. The gas phase outlet is located at the top of the steam drum and connected to the input end of the energy release unit through a gas phase delivery pipeline. The riser is installed in a heating structure.
[0009] In the specific scheme, the heat source of the heating structure is the waste heat within the carbon dioxide energy storage system plant area.
[0010] In a specific embodiment, the energy storage unit includes a compressor and an energy storage heat exchanger connected sequentially between the gas storage unit and the condensation unit.
[0011] In a specific embodiment, the energy release unit includes an energy release heat exchanger and a turbine connected sequentially between the evaporation unit and the gas storage unit.
[0012] A second aspect of the present invention is to provide a control method for a carbon dioxide energy storage system as described above, the control method comprising an energy storage stage and an energy release stage; wherein, In the energy storage stage: atmospheric carbon dioxide gas in the gas storage unit is input into the energy storage unit, compressed and pressurized and cooled in the energy storage unit, and then transported to the condensation unit, where it is condensed and liquefied to form liquid carbon dioxide, which is then transported to the liquid storage unit for storage. In the energy release stage: the liquid carbon dioxide in the storage unit is transported to the steam drum evaporator by gravity through the flow control device. After evaporation and vaporization in the steam drum evaporator to form carbon dioxide gas, it is transported to the energy release unit. The energy release unit then further heats and performs work to transform it into atmospheric pressure carbon dioxide gas, which is then transported to the gas storage unit for storage. The flow control device controls the flow rate of liquid carbon dioxide delivered to the steam drum evaporator, thereby controlling the temperature of the carbon dioxide gas delivered from the steam drum evaporator to the energy release unit.
[0013] In the specific scheme, during the energy release phase: when the energy release phase starts running, the first valve is opened and the second valve is closed, and the flow control device delivers liquid carbon dioxide to the steam drum evaporator at the maximum flow rate through the first liquid phase pipeline; when the energy release phase enters a stable operating condition, the second valve is opened and the first valve is closed, and the flow control device switches to delivering liquid carbon dioxide to the steam drum evaporator through the second liquid phase pipeline, and controls the delivery flow rate of liquid carbon dioxide by controlling the opening degree of the second valve.
[0014] In a specific embodiment, the flow rate of liquid carbon dioxide supplied to the steam drum evaporator is controlled by the flow control device, thereby controlling the temperature of the carbon dioxide gas supplied from the steam drum evaporator to the energy release unit, includes: When the temperature of the carbon dioxide gas supplied to the energy release unit by the steam drum evaporator is greater than a preset temperature threshold, the flow control device increases the flow rate of liquid carbon dioxide supplied to the steam drum evaporator, raises the liquid level of liquid carbon dioxide in the steam drum evaporator, thereby reducing the temperature of the carbon dioxide gas supplied to the energy release unit. When the temperature of the carbon dioxide gas supplied to the energy release unit by the steam drum evaporator is lower than a preset temperature threshold, the flow control device reduces the flow rate of liquid carbon dioxide supplied to the steam drum evaporator, lowers the liquid carbon dioxide level in the steam drum evaporator, thereby increasing the temperature of the carbon dioxide gas supplied to the energy release unit.
[0015] The carbon dioxide energy storage system and its control method provided in this invention include an evaporation unit comprising a flow control device and a steam drum evaporator. The steam drum evaporator replaces the traditional evaporator to evaporate and vaporize liquid carbon dioxide before it is delivered to the energy release component. The liquid inlet of the steam drum evaporator is positioned below the output end of the storage unit, allowing the liquid carbon dioxide stored in the storage unit to be automatically delivered to the steam drum evaporator by gravity via the flow control device. This eliminates the need for a transfer pump (e.g., a carbon dioxide shielded pump) to provide power. Therefore, on the one hand, avoiding the use of a transfer pump reduces plant power consumption, thus improving the efficiency of the carbon dioxide energy storage system; on the other hand, it reduces the risk of equipment damage caused by cavitation when using a transfer pump, thereby improving the stability of system operation. Furthermore, by controlling the flow rate of the liquid carbon dioxide delivered to the steam drum evaporator through the flow control device, the temperature of the carbon dioxide gas output from the steam drum evaporator can be controlled. This allows the temperature of the carbon dioxide gas delivered to the energy release unit to be stably controlled within a system-set range, further enhancing the stability of system operation. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the carbon dioxide energy storage system in an embodiment of the present invention; Figure 2 This is a schematic diagram of the evaporation unit in an embodiment of the present invention. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the drawings. The embodiments of the present invention shown in and described with reference to the drawings are merely exemplary, and the present invention is not limited to these embodiments.
[0018] It should be noted that the same or similar reference numerals in the accompanying drawings of the embodiments of the present invention correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," and "right" 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 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, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.
[0019] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.
[0020] This invention first provides a carbon dioxide energy storage system, such as... Figure 1 As shown, the carbon dioxide energy storage system mainly includes a gas storage unit 100, an energy storage unit 200, a condensation unit 300, a liquid storage unit 400, an evaporation unit 500, and an energy release unit 600 connected in a closed loop. The gas storage unit 100 stores gaseous carbon dioxide at atmospheric pressure, and the liquid storage unit 400 stores liquid carbon dioxide. The atmospheric pressure carbon dioxide gas flowing out of the gas storage unit 100 is compressed and heat-exchanged by the energy storage unit 200 and condensed by the condensation unit 300, transforming into liquid carbon dioxide at a preset energy storage pressure, which flows into the liquid storage unit 400 for storage, thus completing energy storage. The liquid carbon dioxide output from the liquid storage unit 400 is evaporated and vaporized by the evaporation unit 500 and expanded and released by the energy release unit 600, transforming into gaseous carbon dioxide at atmospheric pressure, which flows into the gas storage unit 100 for storage, thus completing energy release and application.
[0021] Typically, during off-peak electricity demand periods, the energy storage unit 200 and the condensation unit 300 compress and liquefy gaseous carbon dioxide into liquid carbon dioxide, which is then stored in the liquid storage unit 400, converting energy into compressible energy and thermal energy for storage. During peak electricity demand periods, the evaporation unit 500 and the energy release unit 600 vaporize and expand the liquid carbon dioxide, releasing the stored energy and converting it into electrical energy for use. The specific composition and structure of the gas storage unit 100, the energy storage unit 200, the condensation unit 300, the liquid storage unit 400, and the energy release unit 600 can be implemented with reference to existing technologies.
[0022] As a specific example, in this embodiment, such as Figure 1 As shown, the energy storage unit 200 mainly includes a compressor 201 and an energy storage heat exchanger 202 connected between the gas storage unit 100 and the condensation unit 300. The gaseous carbon dioxide output from the gas storage unit 100 is compressed by the compressor 201, cooled by the energy storage heat exchanger 202, and then condensed and liquefied by the condensation unit 300 to form liquid carbon dioxide, which is stored in the liquid storage unit 400.
[0023] As a specific example, in this embodiment, such as Figure 1As shown, the energy release unit 600 mainly includes an energy release heat exchanger 601 and a turbine 602 connected between the evaporation unit 500 and the gas storage unit 100. The liquid carbon dioxide output from the liquid storage unit 400 is evaporated and vaporized in the evaporation unit 500 and then fed into the energy release heat exchanger 601 for further heating to increase the temperature. It is then fed into the turbine 602 to perform work (e.g., generate electricity) and release energy, transforming into atmospheric pressure gaseous carbon dioxide which is stored in the gas storage unit 100.
[0024] like Figure 2 As shown, in this embodiment, the evaporation unit 500 includes a flow control device 1 and a steam drum evaporator 2. The input end of the flow control device 1 is connected to the output end of the liquid storage unit 400, and the output end of the flow control device 1 is connected to the liquid phase inlet of the steam drum evaporator 2. The gas phase outlet of the steam drum evaporator 2 is connected to the input end of the energy release unit 600, specifically to the input end of the energy release heat exchanger 601 in the energy release unit 600. The flow control device 1 is used to transport the liquid carbon dioxide stored in the liquid storage unit 400 to the steam drum evaporator 2. The steam drum evaporator 2 is used to evaporate and vaporize the liquid carbon dioxide to form carbon dioxide gas, and then transport the carbon dioxide gas to the energy release unit 600.
[0025] In this invention, the liquid inlet of the steam drum evaporator 2 is positioned below the output end of the liquid storage unit 400, allowing the liquid carbon dioxide stored in the liquid storage unit 400 to be automatically transported to the steam drum evaporator 2 by gravity through the flow control device 1. Therefore, the carbon dioxide energy storage system of this invention can transport liquid carbon dioxide to the evaporation unit 500 without the need for a transfer pump (e.g., a carbon dioxide shielded pump). This reduces plant power consumption and improves the efficiency of the carbon dioxide energy storage system by avoiding the use of a transfer pump, and also reduces the risk of equipment damage caused by cavitation when using a transfer pump, thus improving the operational stability of the carbon dioxide energy storage system.
[0026] The flow control device 2 is configured to control the flow rate of liquid carbon dioxide supplied to the steam drum evaporator 1, thereby controlling the temperature of the carbon dioxide gas supplied by the steam drum evaporator 2 to the energy release unit 600. Thus, the carbon dioxide energy storage system of this invention can stably control the temperature of the carbon dioxide gas supplied to the energy release unit 600 within a system-set range, further improving the stability of system operation.
[0027] In this embodiment, as Figure 2As shown, the flow control device 1 includes a first liquid phase pipeline 11 and a second liquid phase pipeline 12 connected in parallel between the output end of the liquid storage unit 400 and the liquid phase inlet of the steam drum evaporator 2. A first valve 13 is provided on the first liquid phase pipeline 11, and a second valve 14 is provided on the second liquid phase pipeline 12. The first valve 13 is a gate valve, and the second valve 14 is a flow regulating valve.
[0028] Specifically, during the initial startup of the energy release phase, the first valve 13 is opened and the second valve 14 is closed. The flow control device 1 then delivers liquid carbon dioxide to the steam drum evaporator 2 at maximum flow rate through the first liquid phase pipeline 11. Once the energy release phase reaches stable operating conditions, the second valve 14 is opened and the first valve 13 is closed. The flow control device 1 then switches to delivering liquid carbon dioxide to the steam drum evaporator 2 through the second liquid phase pipeline 12, and controls the flow rate of liquid carbon dioxide by controlling the opening degree of the second valve 14.
[0029] Furthermore, such as Figure 2 As shown, a third valve 15 is respectively installed on both sides of the second valve 14 on the second liquid phase pipeline 12. The third valve 15 is a gate valve. When switching to transport liquid carbon dioxide through the second liquid phase pipeline 12, both third valves 15 are opened, and then the flow rate of liquid carbon dioxide is controlled by controlling the opening degree of the second valve 14. When it is necessary to shut down the second liquid phase pipeline 12, both third valves 15 are closed first, and then the second valve 14 is closed.
[0030] In this embodiment, as Figure 2 As shown, the steam drum evaporation device 2 includes a steam drum 21, a downcomer 22, a lower header 23, and an upcomer 24 connected in sequence. The liquid phase inlet is located on one side of the steam drum 21 and connected to the output end of the flow control device 1. The gas phase outlet is located on the top of the steam drum 21 and connected to the input end of the energy release unit 600 through a gas phase delivery pipeline 26. The upcomer 24 passes through a heating structure 25. Liquid carbon dioxide, input from the liquid inlet to the steam drum 21, is transported from the bottom of the steam drum 21 to the riser 24 via the downcomer 22 and the lower header 23. The heating structure 25 heats the riser 24, causing some of the liquid carbon dioxide in the riser 24 to evaporate and vaporize, resulting in a gas-liquid two-phase mixture of carbon dioxide, which is then transported back to the steam drum 21. The gas-liquid two-phase mixture of carbon dioxide separates within the steam drum 21. The liquid phase carbon dioxide descends to the bottom of the steam drum 21 and enters the next evaporation and vaporization cycle, while the gas phase carbon dioxide rises to the top of the steam drum 21 and is output from the gas phase outlet to the energy release unit 600.
[0031] In a preferred embodiment, the heat source for the heating structure 25 is waste heat from within the carbon dioxide energy storage system plant area. For example... Figure 2 The arrows on the side of the heating structure 25 indicate the heat source input to the heating structure 25.
[0032] Based on the carbon dioxide energy storage system provided in the above embodiments, this invention also provides a control method for the carbon dioxide energy storage system, the control method including an energy storage stage and an energy release stage.
[0033] In the energy storage stage: atmospheric carbon dioxide gas in the gas storage unit 100 is input into the energy storage unit 200. The atmospheric carbon dioxide gas is compressed and pressurized in the energy storage unit 200 and then cooled by heat exchange before being transported to the condensation unit 300. The condensation unit 300 then condenses and liquefies the gas to form liquid carbon dioxide, which is then transported to the liquid storage unit 400 for storage.
[0034] In the energy release stage: the liquid carbon dioxide in the liquid storage unit 400 is transported to the steam drum evaporator 2 by gravity through the flow control device 1. The liquid carbon dioxide evaporates and vaporizes in the steam drum evaporator 2 to form carbon dioxide gas, which is then transported to the energy release unit 600. The carbon dioxide gas is further heated by the energy release unit 600 and performs work, and then it is transformed into atmospheric pressure carbon dioxide gas, which is then transported to the gas storage unit 100 for storage.
[0035] During the energy release phase, the flow control device 1 controls the flow rate of liquid carbon dioxide delivered to the steam drum evaporator 2, thereby controlling the temperature of the carbon dioxide gas delivered by the steam drum evaporator 2 to the energy release unit 600.
[0036] In this embodiment, during the energy release phase: When the energy release phase starts running, the first valve 13 is opened and the second valve 14 is closed. The flow control device 1 delivers liquid carbon dioxide to the steam drum evaporator 2 at the maximum flow rate through the first liquid phase pipeline 11.
[0037] Once the energy release phase reaches a stable operating condition, the second valve 14 is opened and the first valve 13 is closed. The flow control device 1 switches to transporting liquid carbon dioxide to the steam drum evaporator 2 through the second liquid phase pipeline 12, and controls the flow rate of liquid carbon dioxide by controlling the opening of the second valve 14, thereby controlling the temperature of the carbon dioxide gas transported by the steam drum evaporator 2 to the energy release unit 600.
[0038] Specifically, when the temperature of the carbon dioxide gas supplied to the energy release unit 600 by the steam drum evaporator 2 is greater than a preset temperature threshold, the flow control device 1 increases the flow rate of the liquid carbon dioxide supplied to the steam drum evaporator 2, raising the liquid carbon dioxide level in the steam drum evaporator 2, i.e., increasing the amount of low-temperature liquid carbon dioxide in the steam drum 21, thereby lowering the temperature of the carbon dioxide gas supplied to the energy release unit 600. When the temperature of the carbon dioxide gas supplied to the energy release unit 600 by the steam drum evaporator 2 is less than the preset temperature threshold, the flow control device 1 decreases the flow rate of the liquid carbon dioxide supplied to the steam drum evaporator 2, lowering the liquid carbon dioxide level in the steam drum evaporator 2, i.e., decreasing the amount of low-temperature liquid carbon dioxide in the steam drum 21, thereby raising the temperature of the carbon dioxide gas supplied to the energy release unit 600.
[0039] In summary, the carbon dioxide energy storage system and its control method provided in the above embodiments of the present invention, by improving the structure of the evaporation unit in the carbon dioxide energy storage system, can transport liquid carbon dioxide to the evaporation unit without the need for a transfer pump to provide transport power, and can also stably control the temperature of the carbon dioxide gas transported from the evaporation unit to the energy release unit within the range set by the system. This not only reduces plant power consumption and improves the efficiency of the carbon dioxide energy storage system, but also enhances the stability of system operation.
[0040] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.
Claims
1. A carbon dioxide energy storage system, comprising a gas storage unit, an energy storage unit, a condensation unit, a liquid storage unit, an evaporation unit, and an energy release unit connected in a closed loop in sequence, characterized in that, The evaporation unit includes a flow control device and a steam drum evaporation device. The input end of the flow control device is connected to the output end of the liquid storage unit, the output end of the flow control device is connected to the liquid phase inlet of the steam drum evaporation device, and the gas phase outlet of the steam drum evaporation device is connected to the input end of the energy release unit. The liquid inlet of the steam drum evaporator is configured to be lower than the output end of the liquid storage unit, so that the liquid carbon dioxide stored in the liquid storage unit can be automatically transported to the steam drum evaporator by the flow control device based on gravity; the steam drum evaporator is used to evaporate and vaporize the liquid carbon dioxide to form carbon dioxide gas, and transport the carbon dioxide gas to the energy release unit. The flow control device is configured to control the flow rate of liquid carbon dioxide supplied to the steam drum evaporator, thereby controlling the temperature of the carbon dioxide gas supplied by the steam drum evaporator to the energy release unit.
2. The carbon dioxide energy storage system according to claim 1, characterized in that, The flow control device includes a first liquid phase pipeline and a second liquid phase pipeline connected in parallel between the output end of the liquid storage unit and the liquid phase inlet of the steam drum evaporator. A first valve is provided on the first liquid phase pipeline, and a second valve is provided on the second liquid phase pipeline. The first valve is a gate valve, and the second valve is a flow regulating valve.
3. The carbon dioxide energy storage system according to claim 2, characterized in that, A third valve, which is a gate valve, is also provided on both sides of the second valve on the second liquid phase pipeline.
4. The carbon dioxide energy storage system according to claim 1, characterized in that, The steam drum evaporation device includes a steam drum, a downcomer, a lower header, and a riser connected in sequence. The liquid phase inlet is located on one side of the steam drum and connected to the output end of the flow control device. The gas phase outlet is located at the top of the steam drum and connected to the input end of the energy release unit through a gas phase delivery pipeline. The riser is inserted into a heating structure.
5. The carbon dioxide energy storage system according to claim 4, characterized in that, The heat source for the heating structure is waste heat from the carbon dioxide energy storage system plant area.
6. The carbon dioxide energy storage system according to any one of claims 1-5, characterized in that, The energy storage unit includes a compressor and an energy storage heat exchanger connected in sequence between the gas storage unit and the condensation unit.
7. The carbon dioxide energy storage system according to any one of claims 1-5, characterized in that, The energy release unit includes an energy release heat exchanger and a turbine connected sequentially between the evaporation unit and the gas storage unit.
8. A control method for a carbon dioxide energy storage system as described in any one of claims 1-7, characterized in that, The control method includes an energy storage stage and an energy release stage; wherein... In the energy storage stage: atmospheric carbon dioxide gas in the gas storage unit is input into the energy storage unit, compressed and pressurized and cooled in the energy storage unit, and then transported to the condensation unit, where it is condensed and liquefied to form liquid carbon dioxide, which is then transported to the liquid storage unit for storage. In the energy release stage: the liquid carbon dioxide in the storage unit is transported to the steam drum evaporator by gravity through the flow control device. After evaporation and vaporization in the steam drum evaporator to form carbon dioxide gas, it is transported to the energy release unit. The energy release unit then further heats and performs work to transform it into atmospheric pressure carbon dioxide gas, which is then transported to the gas storage unit for storage. The flow control device controls the flow rate of liquid carbon dioxide delivered to the steam drum evaporator, thereby controlling the temperature of the carbon dioxide gas delivered from the steam drum evaporator to the energy release unit.
9. The control method for a carbon dioxide energy storage system according to claim 8, characterized in that, During the energy release phase: when the energy release phase starts running, the first valve is opened and the second valve is closed, and the flow control device delivers liquid carbon dioxide to the steam drum evaporator at the maximum flow rate through the first liquid phase pipeline; when the energy release phase enters a stable operating condition, the second valve is opened and the first valve is closed, and the flow control device switches to delivering liquid carbon dioxide to the steam drum evaporator through the second liquid phase pipeline, and controls the delivery flow rate of liquid carbon dioxide by controlling the opening degree of the second valve.
10. The control method for a carbon dioxide energy storage system according to claim 8 or 9, characterized in that, The control of the flow rate of liquid carbon dioxide supplied to the steam drum evaporator by the flow control device, thereby controlling the temperature of the carbon dioxide gas supplied from the steam drum evaporator to the energy release unit, includes: When the temperature of the carbon dioxide gas supplied to the energy release unit by the steam drum evaporator is greater than a preset temperature threshold, the flow control device increases the flow rate of liquid carbon dioxide supplied to the steam drum evaporator, raises the liquid level of liquid carbon dioxide in the steam drum evaporator, thereby reducing the temperature of the carbon dioxide gas supplied to the energy release unit. When the temperature of the carbon dioxide gas supplied to the energy release unit by the steam drum evaporator is lower than a preset temperature threshold, the flow control device reduces the flow rate of liquid carbon dioxide supplied to the steam drum evaporator, lowers the liquid carbon dioxide level in the steam drum evaporator, thereby increasing the temperature of the carbon dioxide gas supplied to the energy release unit.