Working fluid charging and recovery assembly and method for a carbon dioxide energy storage system

Abstract

The application provides a working medium charging and recycling assembly and method of a carbon dioxide energy storage system. The working medium charging and recycling assembly comprises: a liquid storage unit for storing liquid and gaseous carbon dioxide; the liquid storage unit is used for receiving liquid carbon dioxide input by a carbon dioxide tank truck or outputting liquid carbon dioxide to the carbon dioxide tank truck through a liquid phase interface; a pressure balance unit comprising a pressure regulating device and a gaseous phase balance branch pipe; the pressure regulating device is used for converting the carbon dioxide to gas and liquid to make the pressure in the liquid storage unit reach a design pressure; a first end of the gaseous phase balance branch pipe is connected with a first gaseous phase interface; a second end of the gaseous phase balance branch pipe is used for connecting the carbon dioxide tank truck; and gaseous carbon dioxide can flow between the liquid storage unit and the carbon dioxide tank truck through the gaseous phase balance branch pipe to balance the pressure between the liquid storage unit and the carbon dioxide tank truck. The application can realize fast charging and recycling of liquid carbon dioxide, save construction period and reduce project construction cost.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to a working fluid filling and recovery component for a carbon dioxide energy storage system and a working fluid filling and recovery method for a carbon dioxide energy storage system. Background Technology

[0002] Carbon dioxide (CO2) energy storage is a novel physical energy storage technology. CO2 energy storage systems utilize the gas-liquid phase change of CO2 to store energy, with CO2 as the primary working fluid. Existing CO2 energy storage systems generally consist of a gas storage tank, energy storage modules, a liquid storage tank, and an energy release module connected in a closed loop. The gas storage tank contains a cavity to hold gaseous CO2. The energy storage modules, liquid storage tank, and energy release module can be collectively referred to as the working fluid operating system. During operation, CO2 energy storage systems undergo gas-liquid transformations between the gas storage tank and the working fluid operating system. Specifically, in the energy storage and release process of the physical energy storage system, gaseous CO2 flowing from the gas storage tank is transformed into liquid by the energy storage modules and flows into the liquid storage tank to complete energy storage; liquid CO2 flowing from the liquid storage tank is transformed into gas by the energy release module and flows into the gas storage tank to release the stored energy. Before the trial operation of a carbon dioxide energy storage system, it is necessary to fill the system with carbon dioxide working fluid to replace all the air in the system with high-purity carbon dioxide. The existing working fluid filling method is gaseous filling, which involves vaporizing carbon dioxide into gaseous carbon dioxide and then filling it into the system. The filling speed is slow, which seriously affects the project construction and commissioning cycle of the carbon dioxide energy storage system. How to quickly fill the carbon dioxide energy storage system with carbon dioxide working fluid is an important issue to ensure the operation of the carbon dioxide energy storage system. Summary of the Invention

[0003] Therefore, in order to solve the problem of slow working fluid filling speed in existing carbon dioxide energy storage systems, this invention provides a working fluid filling and recovery component and method for carbon dioxide energy storage systems, which can realize rapid filling and recovery of liquid carbon dioxide, saving construction time and reducing project construction costs.

[0004] An embodiment of the present invention provides a working fluid filling and recovery component for a carbon dioxide energy storage system, comprising: a liquid storage unit for storing liquid carbon dioxide and gaseous carbon dioxide, the liquid storage unit having a liquid phase interface and a first gas phase interface at its top; the liquid storage unit is used to receive liquid carbon dioxide from a carbon dioxide tanker through the liquid phase interface during the filling stage or to output liquid carbon dioxide to the carbon dioxide tanker through the liquid phase interface during the recovery stage; a pressure balancing unit, including a pressure regulating device and a gas phase balancing branch pipe, the pressure regulating device being connected to the liquid phase interface and the first gas phase interface respectively; the pressure regulating device being used to perform gas-liquid conversion of carbon dioxide during the filling stage to make the pressure in the liquid storage unit reach the design pressure; a first end of the gas phase balancing branch pipe being connected to the first gas phase interface, and a second end of the gas phase balancing branch pipe being connected to the carbon dioxide tanker; the gaseous carbon dioxide being able to flow between the liquid storage unit and the carbon dioxide tanker through the gas phase balancing branch pipe to balance the pressure between the liquid storage unit and the carbon dioxide tanker.

[0005] In some embodiments, the pressure regulating device includes: a liquefaction section, the working fluid outlet of the liquefaction section being connected to the liquid phase interface, the working fluid side of the liquefaction section being connected to the first gas phase interface, the liquefaction section being used to convert the gaseous carbon dioxide into the liquid carbon dioxide and output the liquid carbon dioxide to the storage unit, so as to reduce the pressure in the storage unit to the design pressure during the filling stage.

[0006] In some embodiments, the pressure balancing unit further includes: a first balancing pipe connected between the first gas phase interface and the liquefaction section; the first end of the gas phase balancing branch pipe connected to the first balancing pipe; or the first end of the gas phase balancing branch pipe connected to the working fluid inlet of the liquefaction section.

[0007] In some embodiments, the pressure regulating device includes: a vaporization section, wherein the working medium inlet of the vaporization section is connected to the liquid phase interface, and the working medium outlet of the vaporization section is connected to the first gas phase interface; the vaporization section is used to convert the liquid carbon dioxide gas output from the storage unit into gaseous carbon dioxide, and output the gaseous carbon dioxide to the storage unit, so as to increase the pressure in the storage unit to the design pressure during the filling stage.

[0008] In some embodiments, the pressure balancing unit further includes: a second balancing pipe, which is connected between the working fluid outlet of the vaporization section and the first gas phase interface; the first end of the gas phase balancing branch pipe is connected to the second balancing pipe.

[0009] In some embodiments, the working fluid filling and recovery component of the carbon dioxide energy storage system further includes a heat exchange component, which is used to heat the liquid carbon dioxide output from the carbon dioxide tanker to a preset filling temperature during the filling stage and output it to the liquid storage unit.

[0010] In some embodiments, the working fluid filling and recovery component of the carbon dioxide energy storage system further includes: a first transmission pipeline, the two ends of which are respectively connected to the liquid storage unit and the carbon dioxide tanker; a delivery pump, which is installed on the first transmission pipeline; and a second transmission pipeline, which is connected in parallel with the delivery pump, and a bypass control valve is installed on the second transmission pipeline.

[0011] In some embodiments, the delivery pump is a bidirectional pump, which is configured to perform a first steering during the filling stage to deliver the liquid carbon dioxide output from the carbon dioxide tanker to the storage unit via the first transmission pipeline; and to perform a second steering during the recovery stage to deliver the liquid carbon dioxide in the storage unit to the carbon dioxide tanker via the first transmission pipeline, wherein the first steering and the second steering are opposite.

[0012] In some embodiments, the working fluid filling and recovery assembly of the carbon dioxide energy storage system further includes the carbon dioxide tanker, which is used to provide liquid carbon dioxide to the liquid storage unit during the filling stage or to receive and store the liquid carbon dioxide output by the liquid storage unit during the recovery stage; the top of the carbon dioxide tanker has a second gas phase interface, and the second end of the gas phase balance branch pipe is connected to the second gas phase interface.

[0013] Some embodiments of the present invention provide a working fluid filling and recovery method for a carbon dioxide energy storage system. Based on the working fluid filling and recovery component of the carbon dioxide energy storage system described in any one of the preceding claims, the working fluid filling and recovery method includes: connecting the carbon dioxide tanker to the gas phase balance branch pipe, and balancing the pressure between the carbon dioxide tanker and the liquid storage unit through the gas phase balance branch pipe; connecting the carbon dioxide tanker to the liquid phase interface; during the filling stage, the carbon dioxide tanker outputs the liquid carbon dioxide to the liquid storage unit; or during the recovery stage, the liquid storage unit outputs the liquid carbon dioxide to the carbon dioxide tanker; during the filling stage, the pressure regulating device performs gas-liquid conversion of the carbon dioxide, so that the pressure in the liquid storage unit reaches the design pressure.

[0014] As can be seen from the above, the embodiments of the present invention can achieve one or more of the following beneficial effects: In this embodiment, the liquid storage unit can be connected to the carbon dioxide tank truck through a liquid phase interface, and the working fluid filling of the carbon dioxide energy storage system can be achieved by filling the liquid storage unit with liquid carbon dioxide, which is faster than filling after vaporization. Furthermore, by setting a gas phase balance branch pipe, the top gas phase space of the liquid storage unit can be connected to the carbon dioxide tank truck to balance the gas phase pressure of the carbon dioxide tank truck and the liquid storage unit, ensuring smooth liquid flow throughout the filling process. Through a pressure regulating device, the pressure inside the liquid storage unit can reach the design pressure during the filling process, so that the operating devices of the subsequent carbon dioxide energy storage system can directly utilize the expansion of the liquid carbon dioxide at the design pressure inside the liquid storage unit to do work. Therefore, the filling and recovery components and methods provided in this embodiment greatly shorten the filling time, save construction time, and significantly reduce project construction costs.

[0015] Furthermore, there is currently no solution for recovering the working fluid in carbon dioxide energy storage systems. The working fluid filling and recovery component of the carbon dioxide energy storage system provided in the above embodiments of the present invention can also discharge the liquid carbon dioxide stored in the liquid storage unit to the carbon dioxide tank truck. During the discharge of liquid carbon dioxide, the gas phase pressure between the carbon dioxide tank truck and the liquid storage unit can be kept consistent through the gas phase balance branch pipe, so that the liquid carbon dioxide can be discharged smoothly. This can provide a safe and reliable guarantee for the maintenance, equipment failure, and expansion of carbon dioxide energy storage system units, and solve the problem of carbon dioxide working fluid recovery. Attached Figure Description

[0016] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the working fluid filling and recovery component of a carbon dioxide energy storage system provided in one embodiment of the present invention.

[0018] Figure 2 for Figure 1 The diagram shows a structural schematic of a specific embodiment of the working fluid filling and recovery component of the carbon dioxide energy storage system.

[0019] Figure 3 for Figure 2 The diagram shows the connection structure of the working fluid filling and recovery component in the carbon dioxide energy storage system.

[0020] Figure 4 for Figure 1 The diagram shows a structural schematic of a specific embodiment of the working fluid filling and recovery component of the carbon dioxide energy storage system.

[0021] Figure 5 for Figure 4The diagram shows the connection structure of the working fluid filling and recovery component in the carbon dioxide energy storage system.

[0022] Figure 6 for Figure 1 The diagram shows a structural schematic of a specific embodiment of the working fluid filling and recovery component of the carbon dioxide energy storage system.

[0023] Figure 7 for Figure 6 The diagram shows the connection structure of the working fluid filling and recovery component in the carbon dioxide energy storage system.

[0024] Figure 8 A schematic diagram of the connection structure of a working fluid filling and recovery component in a carbon dioxide energy storage system, provided as a specific embodiment.

[0025] Figure 9 A schematic diagram of the connection structure of the working fluid filling and recovery component of a carbon dioxide energy storage system provided in another specific embodiment, applied in the carbon dioxide energy storage system.

[0026] Figure 10 A schematic diagram of the connection structure of the working fluid filling and recovery component of a carbon dioxide energy storage system provided in another specific embodiment, applied in the carbon dioxide energy storage system.

[0027] Figure 11 A schematic diagram of the structure of a carbon dioxide tanker in the working fluid filling and recovery assembly of a carbon dioxide energy storage system provided in one embodiment.

[0028] [Explanation of Labels in the Attached Image]

[0029] 10: Liquid storage unit; 11: Liquid phase interface; 12: First gas phase interface; 13: Temperature detection unit; 131: On-site temperature detector; 132: Remote temperature detector; 14: First pressure detection unit; 141: First on-site pressure detector; 142: First remote pressure detector; 15: First liquid level detection unit; 20: Pressure balancing unit; 21: Gas phase balancing branch pipe; 22: First balancing pipe; 23: Second balancing pipe; 24: Pressure regulating device; 30: Carbon dioxide tanker; 31: Second gas phase interface; 32: Second pressure detection unit; 33: Second liquid level detection unit; 41 41: Liquefaction section; 52: Compressor; 53: Gasification section; 54: Energy release heat exchanger; 55: Turbine; 60: Gas storage tank; 71: Heat exchange assembly; 711: Heat exchanger temperature detection unit; 72: First transmission pipeline; 73: Transfer pump; 74: Second transmission pipeline; 75: Bypass control valve; 801: First valve; 802: Second valve; 803: Third valve; 804: Fourth valve; 805: Fifth valve; 806: Sixth valve; 807: Seventh valve; 808: Eighth valve; 809: Ninth valve; 810: First gas phase control valve; 811: First liquid phase control valve. Detailed Implementation

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0031] To enable those skilled in the art to better understand the technical solutions of the present invention, 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, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0033] It should also be noted that the division of multiple embodiments in this invention is only for the convenience of description and should not constitute a special limitation. Features in various embodiments can be combined and referenced in each other without contradiction.

[0034] like Figure 1 As shown, one embodiment of the present invention provides a working fluid filling and recovery component for a carbon dioxide energy storage system, including a liquid storage unit 10 and a pressure balancing unit 20.

[0035] The storage unit 10 is used to store liquid carbon dioxide and gaseous carbon dioxide. The storage unit 10 has a liquid phase interface 11 and a first gas phase interface 12 at its top. The storage unit 10 is used to receive liquid carbon dioxide from the carbon dioxide tanker 30 via the liquid phase interface 11 during the filling phase or to output liquid carbon dioxide to the carbon dioxide tanker 30 via the liquid phase interface 11 during the recovery phase. The storage unit 10 is the part of the carbon dioxide energy storage system used to store liquid carbon dioxide; however, in actual operation, some of the carbon dioxide stored in the storage unit 10 is usually in the form of gaseous carbon dioxide. The storage unit 10 may include, for example, multiple storage containers to provide storage space for liquid carbon dioxide, and the multiple storage containers may be combined in parallel, series, or series-parallel configurations.

[0036] The pressure balancing unit 20 includes a pressure regulating device 24 and a gas phase balancing branch pipe 21. The pressure regulating device 24 is connected to the liquid phase interface 11 and the first gas phase interface 12, respectively. The pressure regulating device 24 is used to perform gas-liquid conversion of carbon dioxide during the filling stage to ensure that the pressure in the storage unit reaches the design pressure. The first end of the gas phase balancing branch pipe 21 is connected to the first gas phase interface 12, and the second end of the gas phase balancing branch pipe 21 is used to connect to the carbon dioxide tank truck 30. Gaseous carbon dioxide can flow between the storage unit 10 and the carbon dioxide tank truck 30 through the gas phase balancing branch pipe to balance the pressure between the storage unit 10 and the carbon dioxide tank truck 30.

[0037] The carbon dioxide tanker truck 30, also known as a carbon dioxide tanker truck, can transport liquid carbon dioxide at normal temperature and high pressure (20℃, 7MPa) or low temperature and high pressure (-40℃, 2MPa). That is, the carbon dioxide tanker truck 30 can store and transport liquid carbon dioxide at different transport pressures such as 7MPa or 2MPa. Before the carbon dioxide energy storage system is put into operation, the liquid carbon dioxide transported by the carbon dioxide tanker truck 30 needs to be filled into the carbon dioxide energy storage system to ensure its normal operation. This can be done by connecting the carbon dioxide tanker truck 30 to the liquid phase interface 11 of the liquid storage unit 10, allowing the liquid carbon dioxide in the carbon dioxide tanker truck 30 to be filled into the liquid storage unit 10 via the liquid phase interface 11. Alternatively, in scenarios such as unit maintenance or equipment failure within the carbon dioxide energy storage system, it is necessary to discharge the carbon dioxide from the carbon dioxide energy storage system. In this case, the liquid carbon dioxide stored in the liquid storage unit 10 can be discharged into the carbon dioxide tanker truck 30 via the liquid phase interface 11 by connecting the carbon dioxide tanker truck 30 to the liquid phase interface 11 of the liquid storage unit 10.

[0038] During the filling stage, the pressure regulating device 24 can perform gas-liquid conversion of carbon dioxide to ensure that the pressure inside the storage unit 10 reaches the design pressure. The design pressure is, for example, the pressure of carbon dioxide inside the storage unit 10 when the carbon dioxide energy storage system is operating normally, and can also be called the energy storage pressure. Since the transportation pressure of the carbon dioxide tanker 30 may differ from the design pressure, the above-mentioned settings ensure that, before the carbon dioxide energy storage system is officially put into operation, not only can carbon dioxide be quickly filled into the storage unit 10, but the pressure of the filled liquid carbon dioxide can also meet the requirements for normal operation.

[0039] In related technologies, liquid carbon dioxide is vaporized through a vaporization device and then filled into a carbon dioxide energy storage system. For large-capacity carbon dioxide energy storage systems, the amount of carbon dioxide required for filling is particularly large. The vaporization filling method is inefficient and easily affected by the external environment. It is extremely difficult to fill in cold weather, and the filling speed after normal vaporization is slow. For example, it would take 10 to 20 hours to fill a carbon dioxide tanker with 20 tons of carbon dioxide using the vaporization method. However, the mass of carbon dioxide required for the normal operation of the entire carbon dioxide energy storage system is as high as thousands of tons. Therefore, the vaporization filling method will result in a long filling cycle for the entire energy storage system to reach operating conditions, which will seriously affect the construction and commissioning cycle of the entire project.

[0040] In this embodiment, the liquid storage unit 10 can be connected to the carbon dioxide tanker 30 via the liquid phase interface 11. The working fluid of the carbon dioxide energy storage system can be filled by filling the liquid storage unit 10 with liquid carbon dioxide. A pressure balancing unit 20 is provided, and the gas phase balancing branch pipe 21 in the pressure balancing unit 20 can connect the top gas phase space of the liquid storage unit 10 to the carbon dioxide tanker 30, thereby balancing the gas phase pressure between the carbon dioxide tanker 30 and the liquid storage unit 10 to ensure smooth liquid flow throughout the filling process. The pressure regulating device 24 can adjust the pressure inside the liquid storage unit to the design pressure to meet normal operation requirements and also maintain pressure balance within the liquid storage unit 10. For example, when the rate of filling carbon dioxide using the vaporization method is approximately 1–2 t / h, for an energy storage system with a circulation volume of 500 t of carbon dioxide working fluid, the entire filling cycle is approximately 250–500 h, which is a long filling cycle. In this embodiment, liquid carbon dioxide can be added to the storage unit 10 for filling, achieving a filling speed of 10-20 t / h. For an energy storage system with a circulation volume of 500 t of carbon dioxide working fluid, the entire filling cycle is about 25-50 hours, which greatly shortens the filling time, saves construction time, and significantly reduces project construction costs.

[0041] In addition, there is currently no solution for the recovery of working fluid in carbon dioxide energy storage systems. The working fluid filling and recovery component of the carbon dioxide energy storage system provided in the above embodiments of the present invention can also discharge the liquid carbon dioxide stored in the liquid storage unit 10 to the carbon dioxide tank truck 30. During the discharge of liquid carbon dioxide, the gas phase pressure between the carbon dioxide tank truck 30 and the liquid storage unit 10 can be kept consistent through the gas phase balance branch pipe 21, so that the liquid carbon dioxide can be discharged smoothly. This can provide a safe and reliable guarantee for the maintenance, equipment failure, and expansion of carbon dioxide energy storage system units, and solve the problem of carbon dioxide working fluid recovery.

[0042] In one embodiment, the first end of the gas phase balancing branch pipe 21 can be directly connected to the first gas phase interface 12. However, in some embodiments, since the first gas phase interface 12 is located at a higher position, the gas phase balancing branch pipe 21 can also be connected to the first gas phase interface 12 in other ways. For example, the gas phase balancing branch pipe 21 can be connected to the gas phase pipeline between the pressure regulating device 24 and the first gas phase interface 12. Selecting a suitable position for the gas phase pipeline according to actual needs can save pipeline materials and reduce installation difficulty.

[0043] In one embodiment, refer to Figure 2The pressure regulating device 24 includes a liquefaction section 41. The working fluid outlet of the liquefaction section 41 is connected to the liquid phase interface 11, and the working fluid side of the liquefaction section 41 is connected to the first gas phase interface 12. The liquefaction section 41 is used to convert gaseous carbon dioxide into liquid carbon dioxide and output the liquid carbon dioxide to the storage unit 10, so as to reduce the pressure in the storage unit 10 to the design pressure during the filling stage. The liquefaction section 41 can be, for example, a condenser, or other device that can convert gaseous carbon dioxide into liquid carbon dioxide, such as a compressor. For example, the liquefaction section 41 achieves liquefaction through non-contact heat exchange. The liquefaction section 41 has a working fluid side and a heat exchange medium side. The heat exchange medium flows in the heat exchange medium side, such as water, heat transfer oil, LNG, Freon, etc., and the working fluid side flows with the working medium (i.e., carbon dioxide). When the liquefaction section 41 is working, the heat exchange medium flowing on the heat exchange medium side exchanges heat with the gaseous carbon dioxide on the working medium side in a non-contact manner, so that the gaseous carbon dioxide is condensed into liquid carbon dioxide and then output from the working medium outlet.

[0044] Therefore, when the liquefaction unit 41 is working, some of the gaseous carbon dioxide in the storage unit 10 can be converted into liquid and then returned to the storage unit 10, thereby reducing the volume of gaseous carbon dioxide in the storage unit 10 and lowering the pressure inside the storage unit 10. For example, if the transport pressure of the carbon dioxide tanker 30 is greater than the design pressure (e.g., the transport pressure is 7 MPa and the design pressure is 6.8 MPa), then the pressure of the liquid carbon dioxide filled into the storage unit 10 is also greater than the design pressure. At this time, the liquefaction unit 41 can convert some of the gaseous carbon dioxide into liquid carbon dioxide during the filling stage to reduce the pressure inside the storage unit 10 to the design pressure. For example, the transport pressure of the carbon dioxide tanker 30 is equal to the design pressure (e.g., the transport pressure is 7 MPa, and the design pressure is 7 MPa), or slightly less than the design pressure (e.g., the transport pressure is 7 MPa, and the design pressure is 7.2 MPa). However, during the filling process, the liquid carbon dioxide expands due to absorbing ambient heat, causing the pressure of the carbon dioxide filled into the storage unit 10 to exceed the design pressure. In this case, the liquefaction section 41 can convert some of the gaseous carbon dioxide into liquid carbon dioxide to maintain the pressure in the storage unit 10 at the design pressure. By setting the liquefaction section 41, the working fluid filling and recovery assembly can be adapted to the carbon dioxide tanker 30 with higher transport pressure to fill the storage unit 10 with liquid carbon dioxide, and can meet the pressure requirements for the formal operation of the carbon dioxide energy storage system in the later stages.

[0045] In some embodiments, the pressure balancing unit 20 further includes a first balancing pipe 22, which is connected between the first gas phase interface 12 and the liquefaction section 41. Gaseous carbon dioxide in the liquid storage unit 10 is transferred to the liquefaction section 41 through the first balancing pipe 22 to be converted into liquid.

[0046] The liquefaction section 41 can be, for example, a device (i.e., a condenser) within a carbon dioxide energy storage system for condensing gaseous carbon dioxide into liquid carbon dioxide. For example, see reference... Figure 3 A carbon dioxide energy storage system includes, for example, a gas storage tank 60 and an energy storage component connecting the gas storage tank 60 and a liquid storage unit 10. The energy storage component includes a liquefaction section 41 (i.e., a condenser) and an energy storage compression section, represented by a compressor 42. The gas storage tank 60 is used to store gaseous carbon dioxide at atmospheric pressure. During the energy storage phase, the energy storage compression section compresses the gaseous carbon dioxide at atmospheric pressure in the gas storage tank 60 to the energy storage pressure. The liquefaction section 41 condenses and liquefies the gaseous carbon dioxide at the energy storage pressure output by the energy storage compression section into liquid carbon dioxide, which is then output to the liquid storage unit 10. In this process, energy is stored in the form of compression energy and thermal energy, realizing an energy storage cycle.

[0047] When the liquefaction section 41 is the condenser in the carbon dioxide energy storage system, the first balance pipe 22 can balance the pressure in the liquid storage unit 10 during the energy storage stage. During the energy storage stage, as the amount of liquid carbon dioxide in the liquid storage unit 10 gradually increases, the pressure will rise. The first balance pipe 22 can maintain the pressure of the liquid storage unit 10 at the energy storage pressure during the energy storage stage. Therefore, in this embodiment, by reusing the condenser of the carbon dioxide energy storage system as the liquefaction section 41, the pressure in the liquid storage unit 10 can be balanced during the filling stage and also during the energy storage stage, realizing the reuse of the equipment at different stages and reducing equipment investment costs.

[0048] Reference Figure 2 The first end of the gas phase balance branch pipe 21 is connected to the first balance pipe 22, that is, the gas phase balance branch pipe 21 is connected to the first gas phase interface 12 through the first balance pipe 22.

[0049] In this embodiment, by connecting the first end of the gas phase balance branch pipe 21 to the first balance pipe 22, the gas phase balance branch pipe 21 can be connected to the first gas phase interface 12, thereby achieving consistent gas phase pressure between the carbon dioxide tanker 30 and the liquid storage unit 10. Furthermore, the connection between the gas phase balance branch pipe 21 and the first gas phase interface 12 via the first balance pipe 22 allows for the selection of a suitable access point on the first balance pipe 22 for convenient installation and operation, and also saves piping materials.

[0050] Or refer to Figure 4 The first end of the gas phase balance branch pipe 21 is connected to the working fluid inlet of the liquefaction section 41. See details... Figure 5The gas phase balance branch pipe 21 is specifically connected between the outlet of the energy storage compression section, represented by the compressor 42, and the liquefaction section 41. The pressure between the liquefaction section 41 and the liquid storage unit 10 can be kept consistent through the first balance pipe 22. Therefore, connecting the gas phase balance branch pipe 21 to the working fluid inlet of the liquefaction section 41 can also achieve the connection of the gas phase balance branch pipe 21, saving pipe materials.

[0051] In addition, during the process of recovering the liquid carbon dioxide in the storage unit 10 to the carbon dioxide tanker 30, the liquefaction unit 41 can be activated to convert some of the gaseous carbon dioxide into liquid carbon dioxide. This can remove some heat, maintain the pressure stability in the storage unit 10, ensure the smooth flow of liquid carbon dioxide, and achieve the effect of rapid recovery.

[0052] In other embodiments, reference is made to Figure 6 The pressure regulating device 24 also includes a vaporization section 51. The working fluid inlet of the vaporization section 51 is connected to the liquid storage unit 10, and the working fluid outlet of the vaporization section 51 is connected to the first gas phase interface 12. The vaporization section 51 is used to convert the liquid carbon dioxide output from the liquid storage unit 10 into gaseous carbon dioxide and output the gaseous carbon dioxide to the liquid storage unit 10. This is to increase the pressure of the liquid storage unit 10 to the design pressure during the filling stage. The vaporization section 51 can be, for example, an evaporator, or other device that can convert liquid carbon dioxide into gaseous carbon dioxide, such as a vaporizer, specifically an ambient temperature vaporizer, a water bath vaporizer, etc. The vaporization section 51 achieves vaporization, for example, through non-contact heat exchange. The vaporization section 51 has, for example, a working fluid side and a heat exchange medium side. The heat exchange medium flows in the heat exchange medium, which can be, for example, water, heat transfer oil, molten salt, etc. The working fluid (i.e., carbon dioxide) flows in the working fluid side. When the vaporization section 51 is working, the heat exchange medium flowing on the heat exchange medium side exchanges heat with the liquid carbon dioxide on the working medium side in a non-contact manner, so as to vaporize the liquid carbon dioxide into gaseous carbon dioxide and then output the gaseous carbon dioxide from the working medium outlet.

[0053] Therefore, when the vaporization unit 51 is working, some of the liquid carbon dioxide in the storage unit 10 can be converted into gaseous state and then flowed back into the storage unit 10, causing the pressure inside the storage unit 10 to rise. For example, if the transport pressure of the carbon dioxide tanker 30 is lower than the preset pressure (e.g., the transport pressure is 2 MPa and the design pressure is 7 MPa), then the pressure of the liquid carbon dioxide filled into the storage unit 10 is lower than the design pressure. At this time, the vaporization unit 51 can vaporize some of the liquid carbon dioxide into gaseous carbon dioxide during the filling stage to increase the pressure inside the storage unit 10 and maintain the design pressure inside the storage unit 10. By setting up the vaporization unit 51, it is possible to adapt to the filling of liquid carbon dioxide into the storage unit 10 by the carbon dioxide tanker 30 with a lower transport pressure, maintain the pressure balance inside the storage unit 10 to ensure the filling speed, and meet the pressure requirements for the formal operation of the carbon dioxide energy storage system in the later stage.

[0054] The pressure balancing unit 20 also includes a second balancing pipe 23, which is connected between the working medium outlet of the vaporization unit 51 and the first gas phase interface 12. The gaseous carbon dioxide output from the vaporization unit 51 can flow back to the liquid storage unit 10 through the second balancing pipe 23 to balance the pressure inside the liquid storage unit 10.

[0055] Among them, the vaporization section 51 is, for example, a device (i.e., an evaporator) within a carbon dioxide energy storage system for evaporating liquid carbon dioxide into gaseous carbon dioxide. For example, refer to... Figure 7 The carbon dioxide energy storage system includes a gas storage tank 60 and an energy release assembly connecting the gas storage tank 60 and the liquid storage unit 10. The energy release assembly includes a vaporization section 51 (i.e., an evaporator), an energy release expansion section represented by a turbine 53 and an energy release heat exchanger 52. During the energy release phase, the vaporization section 51 evaporates the liquid carbon dioxide stored in the liquid storage unit 10 into gaseous carbon dioxide. The energy release heat exchanger 52 in the energy release expansion section further heats and expands the gaseous carbon dioxide. The turbine 53 uses the expansion of the high-temperature gaseous carbon dioxide to do work and outputs gaseous carbon dioxide at normal temperature and pressure to the gas storage tank 60 for storage, completing the energy release cycle.

[0056] When the vaporization section 51 is the evaporator in the carbon dioxide energy storage system, during the energy release phase, as the amount of liquid carbon dioxide in the storage unit 10 gradually decreases, the pressure drops. The pressure of the storage unit 10 can be maintained stable through the second balance pipe 23. Therefore, in this embodiment, by reusing the evaporator of the carbon dioxide energy storage system as the vaporization section 51, it is possible to maintain the storage unit 10 at the design pressure during the filling phase and maintain the pressure balance within the storage unit 10 during the energy release phase. This allows for the reuse of the equipment at different times and reduces equipment investment costs.

[0057] In some embodiments, the first end of the gas phase balancing branch pipe 21 is connected to the second balancing pipe 23. In this embodiment, by connecting the first end of the gas phase balancing branch pipe 21 to the second balancing pipe 23, the gas phase balancing branch pipe 21 can be connected to the first gas phase interface 12, thereby achieving consistent gas phase pressure between the carbon dioxide tanker 30 and the liquid storage unit 10. Furthermore, since the gas phase balancing branch pipe 21 is connected to the first gas phase interface 12 via the second balancing pipe 23, a suitable connection point can be selected on the second balancing pipe 23 for convenient installation and operation, and also saves piping materials.

[0058] In some embodiments, such as Figure 8As shown, the working fluid filling and recovery assembly of the carbon dioxide energy storage system includes a liquefaction section 41, a vaporization section 51, a first balancing pipe 22, and a second balancing pipe 23. The first balancing pipe 22 and the second balancing pipe 23 share a common pipe section near the liquid storage unit 10. The first end of the gas phase balancing branch pipe 21 can be connected to this common pipe section, which also has the effect of balancing the pressure of the liquid storage unit 10 and the carbon dioxide tanker 30.

[0059] In some embodiments, the pressure regulating device 24 may include both a liquefaction section 41 and a vaporization section 51, which can adapt to carbon dioxide tank trucks 30 with different transport pressures during the filling stage. In some embodiments, the pressure regulating device 24 may also include an expansion section (which may be the energy release expansion section of a carbon dioxide energy storage system) and a compression section (which may be the energy storage compression section of a carbon dioxide energy storage system). If it is necessary to recover the liquid carbon dioxide in the storage unit 10 to the carbon dioxide tank truck 30 at a transport pressure lower than the design pressure during the recovery stage, a portion of the liquid carbon dioxide can first be vaporized into gaseous carbon dioxide by the vaporization section 51 and then transported to the expansion section for expansion and work. The gaseous carbon dioxide can then be compressed to a pressure lower than the design pressure by the compression section and then liquefied by the liquefaction section 41. If the pressure of the liquid carbon dioxide output by the liquefaction section 41 is still higher than the transport pressure, the gas-liquid conversion cycle of liquid carbon dioxide through the vaporization section 51, expansion section, compression section, and liquefaction section 41 continues until the pressure of the liquid carbon dioxide in the storage unit 10 reaches the transport pressure of the carbon dioxide tank truck 30. For example, if the normal operating pressure of a carbon dioxide energy storage system is 7 MPa, which is also the design pressure, and the liquid carbon dioxide needs to be recovered into the carbon dioxide tanker 30 at a transportation pressure of 2 MPa during the recovery phase, some of the liquid carbon dioxide in the storage unit 10 can be vaporized into gaseous carbon dioxide by the vaporization section 51, then expanded by the expansion section to do work, and then compressed by the compression section to a medium-pressure gaseous carbon dioxide of, for example, 5 MPa. The medium-pressure gaseous carbon dioxide output by the compression section is liquefied by the liquefaction section 41 and returned to the storage unit 10. At this time, the pressure of the liquid carbon dioxide output by the liquefaction section 41 is still higher than 2 MPa. Therefore, the medium-pressure gaseous carbon dioxide can be vaporized again by the vaporization section 51, expanded by the expansion section to do work, compressed by the compressor, and liquefied by the liquefaction section 41. After multiple cycles, the pressure in the storage unit 10 can reach 2 MPa, thus achieving recovery at a lower transportation pressure. Since the gas phase balance branch pipe 21 can maintain the pressure balance between the liquid storage unit 10 and the carbon dioxide tanker 30, the process of depressurizing the liquid storage unit 10 to a low transport pressure by combining the vaporization section 51, expansion section, compression section and liquefaction section 41 can be carried out simultaneously with the process of the liquid storage unit 10 outputting liquid carbon dioxide to the carbon dioxide tanker 30.

[0060] In some embodiments, such as Figure 9As shown, the working fluid filling and recovery component of the carbon dioxide energy storage system also includes a heat exchange component 71. The heat exchange component 71 is used to heat the liquid carbon dioxide output from the carbon dioxide tanker 30 to a preset filling temperature and then output it to the liquid storage unit 10. The heat exchange component 71 includes, for example, a heat exchanger, which can be an electric heater, a water bath heat exchanger, an ambient temperature heat exchanger, a flue gas heat exchanger, a steam heat exchanger, etc. The heat exchange medium flows in the hot side channel of the heat exchanger to heat the liquid carbon dioxide flowing through the cold side channel of the heat exchanger. The heat exchange medium can be, for example, an industrial waste heat heat exchange medium, water, heat transfer oil, molten salt, etc.

[0061] The heat exchange assembly 71 also includes, for example, a heat exchanger temperature detection unit 711 (see reference). Figure 10 This is used to detect the temperature of the liquid carbon dioxide at the outlet of the heat exchanger to ensure that the liquid carbon dioxide entering the storage unit 10 reaches the preset filling temperature. Currently, due to the lower cost of cryogenic transportation, the liquid carbon dioxide transported by the carbon dioxide tanker 30 is generally as low as -40°C. The heat exchange component 71 can, for example, raise the temperature of the liquid carbon dioxide to about -20 to 20°C to match the normal operating temperature of the storage unit 10 and related pipelines and valves.

[0062] In some embodiments, a temperature detection unit 13 may also be provided on the liquid storage unit 10 to detect the temperature inside the liquid storage unit 10. The temperature detection unit 13 may include, for example, a local temperature detector 131 and a remote temperature detector 132 (see reference). Figure 10 The on-site temperature detector 131 can be, for example, a liquid expansion thermometer, a solid expansion thermometer, a pressure thermometer, a thermocouple thermometer, or a resistance temperature detector (RTD). The remote temperature detector 132 includes, for example, a temperature sensor and a temperature transmitter, which can convert the temperature signal into a remote voltage or current signal output for easy remote monitoring and control. The temperature detection unit 13 can also be a remote bimetallic thermometer, which combines the remote signal transmission function of an RTD or thermocouple with the local indication function of a bimetallic thermometer, meeting both on-site temperature measurement and remote monitoring needs. The temperature detection unit 13 can also ensure that the liquid carbon dioxide input to the storage unit 10 reaches the preset filling temperature.

[0063] In some embodiments, refer to Figure 11 The working fluid filling and recovery assembly of the carbon dioxide energy storage system also includes a first transmission pipe 72, a transfer pump 73, and a second transmission pipe 74. The first transmission pipe 72 is connected to the liquid storage unit 10 at its opposite ends. Figure 11(Not shown) and a carbon dioxide tanker 30. A transfer pump 73 is installed on a first transfer pipe 72. A second transfer pipe 74 is connected in parallel with the transfer pump 73, and a bypass control valve 75 is installed on the second transfer pipe 74. The first transfer pipe 72 and the second transfer pipe 74 are used to transfer liquid carbon dioxide between the carbon dioxide tanker 30 and the storage unit 10. The transfer pump 73 can be, for example, a centrifugal pump, a pipeline pump, or a pneumatic pump. The second transfer pipe 74 can be used to allow liquid carbon dioxide to flow from the carbon dioxide tanker 30 into the storage unit 10 by gravity or from the storage unit 10 into the carbon dioxide tanker 30 when the liquid level difference between the carbon dioxide tanker 30 and the storage unit 10 is large. When the liquid level difference between the carbon dioxide tanker 30 and the storage unit 10 is insufficient for the liquid carbon dioxide to flow by gravity, the bypass control valve 75 can be closed and the transfer pump 73 can be started to transfer the liquid carbon dioxide. The parallel connection of the second transfer pipe 74 and the transfer pump 73 allows the liquid carbon dioxide transfer method to be selected according to different needs, thus saving energy.

[0064] In some embodiments, the transfer pump 73 is a bidirectional pump. During the filling phase, the transfer pump 73 performs a first rotation, transporting liquid carbon dioxide output from the carbon dioxide tanker 30 to the storage unit 10 via the first transfer pipe 72; during the recovery phase, it performs a second rotation, transporting liquid carbon dioxide from the storage unit 10 back to the carbon dioxide tanker 30 via the first transfer pipe 72. The first and second rotations are opposite. Setting the transfer pump 73 as a bidirectional pump allows for bidirectional transfer of liquid carbon dioxide between the carbon dioxide tanker 30 and the storage unit 10 by changing the pump's rotation direction. During filling, the transfer pump 73 rotates in the forward direction (first direction) to transport liquid carbon dioxide from the carbon dioxide tanker 30 to the storage unit 10. During recovery, the transfer pump 73 rotates in the reverse direction (second direction) to transport liquid carbon dioxide from the storage unit 10 back to the carbon dioxide tanker 30. Alternatively, in other embodiments, two pumps can be used to separately achieve liquid carbon dioxide filling and recovery; this embodiment is not limited to this.

[0065] In some embodiments, the working fluid filling and recovery assembly of any of the aforementioned carbon dioxide energy storage systems includes the carbon dioxide tanker 30. The carbon dioxide tanker 30 is used to provide liquid carbon dioxide to the storage unit 10 during the filling phase or to receive and store the liquid carbon dioxide output from the storage unit 10 during the recovery phase. The top of the carbon dioxide tanker 30 has a second gas phase interface 31, and the second end of the gas phase balance branch pipe 21 is connected to the second gas phase interface 31. In some embodiments, for example, the carbon dioxide tanker 30 and the liquid phase interface 11 can be connected via a detachable liquid phase temporary hose, and the carbon dioxide tanker 30 can be connected to the second end of the gas phase balance branch pipe 21 via a detachable gas phase temporary hose. The liquid phase temporary hose and the gas phase temporary hose can be removed after filling or recovery is completed, making operation convenient. With the second gas phase interface 31 provided on the top of the carbon dioxide tanker 30, when storing carbon dioxide, the lower part of the carbon dioxide tanker 30 is the liquid phase space of liquid carbon dioxide, and the top part is the gas phase space of gaseous carbon dioxide. The gas phase space at the top of the liquid storage unit 10 is connected to the gas phase space at the top of the carbon dioxide tank truck 30 through the first gas phase interface 12, the gas phase balance branch pipe 21 and the second gas phase interface 31, so as to maintain the same pressure in the liquid storage unit 10 and the carbon dioxide tank truck 30 and ensure smooth transmission of liquid carbon dioxide.

[0066] In some embodiments, refer to Figure 10 The working fluid filling and recovery assembly of the carbon dioxide energy storage system also includes a pressure detection device and a first gas phase control valve 810. The pressure detection unit includes a first pressure detection unit 14 and a second pressure detection unit 32. Figure 11 The first pressure detection unit 14 is used to detect the pressure inside the liquid storage unit 10. The second pressure detection unit 32 is used to detect the pressure inside the carbon dioxide tanker 30. The first gas phase control valve 810 is used to operate based on the detection results of the first pressure detection unit 14 and the second pressure detection unit 32.

[0067] The first pressure detection unit 14 may include, for example, a first on-site pressure detector 141, which may be a pressure gauge, specifically, according to the reading method, it can be divided into pointer type pressure gauge or digital pressure gauge. For example, according to its pressure measurement principle, it may be an elastic pressure gauge, a liquid column pressure gauge, a diaphragm pressure gauge, a piston pressure gauge, etc., which can facilitate reading by on-site operators. The first pressure detection unit 14 may also include a first remote pressure detector 142, which may include a pressure sensor that can convert pressure into an electrical signal output, specifically, it may be a resistive pressure sensor, a piezoelectric pressure sensor, a capacitive pressure sensor, a thin-film pressure sensor, etc. The first remote pressure detector 142 may transmit the measured pressure value to a receiving end (e.g., a control component) through wireless transmission technology to realize wireless telemetry function. The second pressure detection unit 32 may be equipped with an on-site or remote pressure detector with reference to the first pressure detection unit 14 to monitor the pressure inside the carbon dioxide tanker 30.

[0068] The first gas phase control valve 810 is, for example, an electric valve, which can electrically control its opening. Specifically, the opening degree of the first gas phase control valve 810 can be controlled according to the detection results of the first pressure detection unit 14 and the second pressure detection unit 32. For example, when the carbon dioxide tanker 30 is connected to the second end of the gas phase balance branch pipe 21 and the carbon dioxide tanker 30 is connected to the liquid phase interface 11 during filling, the first gas phase control valve 810 is first slowly opened according to the first pressure detection unit 14 to maintain the pressure rise rate of the liquid storage unit 10 within a specified range, for example, less than 0.1 MPa / min. When the pressure of the liquid storage unit 10 and the carbon dioxide tanker 30 reaches equilibrium, the first gas phase control valve 810 is fully open. For example, during recovery, when connecting the carbon dioxide tanker 30 to the second end of the gas phase balance branch pipe 21 and the carbon dioxide tanker 30 to the liquid phase interface 11, the first gas phase control valve 810 is slowly opened by the second pressure detection unit 32 to maintain the pressure rise rate of the carbon dioxide tanker 30 within a specified range, for example, less than 0.1 MPa / min. When the pressures of the liquid storage unit 10 and the carbon dioxide tanker 30 reach equilibrium (when the pressure difference is less than a preset value), the first gas phase control valve 810 is fully opened. In this embodiment, the pressure detection device and the first gas phase control valve can more accurately determine the pressure status of the liquid storage unit 10 and the carbon dioxide tanker 30, and facilitate better operation.

[0069] In some embodiments, the working fluid filling and recovery assembly of the carbon dioxide energy storage system further includes a liquid level detection device, as shown in the reference. Figure 10 and Figure 11The liquid level detection device includes a first liquid level detection unit 15 and a second liquid level detection unit 33. The first liquid level detection unit 15 is used to detect the liquid level in the storage unit 10. The second liquid level detection unit 33 is used to detect the liquid level in the carbon dioxide tanker 30. The first liquid level detection unit 15 and the second liquid level detection unit 33 can be, for example, a glass plate level gauge, a magnetic float level gauge, a radar level gauge, a capacitive level gauge, a float level gauge, an ultrasonic level gauge, etc. The storage unit 10 includes, for example, multiple parallel energy storage containers. For example, each energy storage container is equipped with a level gauge to independently sense the liquid level in each energy storage container. For example, when the carbon dioxide tanker 30 fills the storage unit 10 with liquid carbon dioxide, if the first liquid level detection unit 15 determines that the liquid level in one energy storage container exceeds a first preset liquid level, the system switches to another energy storage container for filling. If the second liquid level detection unit 33 determines that the liquid level in one carbon dioxide tanker 30 is lower than a second preset liquid level, the system switches to another carbon dioxide tanker 30 for filling, until filling is complete. For example, when liquid carbon dioxide is discharged from the storage unit 10 to the carbon dioxide tanker 30 for recovery, if the first liquid level detection unit 15 determines that the liquid level in one storage container is lower than a third preset liquid level, the other storage container is switched to discharge liquid carbon dioxide. If the second liquid level detection unit 33 determines that the liquid level in one carbon dioxide tanker 30 is higher than a fourth preset liquid level, the other carbon dioxide tanker 30 is switched to receive liquid carbon dioxide, until recovery is complete. This embodiment, by setting a liquid level detection device, facilitates the determination of the liquid level status in the storage unit 10 and the carbon dioxide tanker 30, allowing for adjustments to the filling and recovery operations based on the liquid level status, and preventing safety issues when the liquid level is too low or too high. In some embodiments, automatic switching can be achieved by combining the liquid level detection device and an automatic control valve, making operation more convenient and safer.

[0070] In some embodiments, the working fluid filling and recovery assembly of the carbon dioxide energy storage system further includes a control assembly. The control assembly is a controller that controls the devices within the working fluid filling and recovery assembly, including but not limited to a central processing unit, a readable storage medium, a controller, and a PLC control unit. The control assembly is, for example, electrically connected to the delivery pump 73, pressure detection device, liquid level detection device, temperature detection device, and first gas phase control valve 810 mentioned in the foregoing embodiments. The control assembly can, for example, receive the detection results output by the pressure detection device, liquid level detection device, and temperature detection device, and issue corresponding control commands based on the detection results to achieve automated control, making control more precise and operation more convenient and safer.

[0071] Figure 10This diagram illustrates the structure of the working fluid filling and recovery assembly of the carbon dioxide energy storage system provided in this application. The working fluid filling and recovery assembly includes a liquid storage unit 10, a pressure balancing unit 20, a carbon dioxide tanker 30, and a heat exchange assembly 71. The pressure balancing unit 20 includes a pressure regulating device 24 and a gas phase balancing branch pipe 21. The carbon dioxide energy storage system also includes a gas storage tank 60, an energy storage assembly represented by a compressor 42, and an energy release assembly represented by a turbine 53. The liquid storage unit 10 stores liquid carbon dioxide, the gas storage tank 60 stores gaseous carbon dioxide, the compressor 42 compresses the gaseous carbon dioxide stored in the gas storage tank 60 to the designed energy storage pressure, and the pressure regulating device 24 includes a liquefaction section 41 and a vaporization section 51. The liquefaction section 41 also acts as a condenser in the energy storage assembly to condense the gaseous carbon dioxide at the designed energy storage pressure into liquid carbon dioxide before outputting it to the liquid storage unit 10. The vaporization unit 51 also functions as an evaporator in the energy release assembly to evaporate the liquid carbon dioxide in the storage unit 10 into gaseous carbon dioxide. The energy release heat exchanger 52 further heats and expands the evaporated gaseous carbon dioxide. The turbine 53 utilizes the expanded high-temperature gaseous carbon dioxide to perform work and outputs it to the gas storage tank 60 for storage. The pressure balancing unit 20 includes a first balancing pipe 22 connected between the liquefaction unit 41 and the first gas phase interface 12. A first valve 801 is installed on the first balancing pipe 22 to control the opening and closing of the first balancing pipe 22. The pressure balancing unit 20 also includes a second balancing pipe 23 connected between the working fluid outlet of the vaporization unit 51 and the first gas phase interface 12. A second valve 802 is installed on the second balancing pipe 23 to control the opening and closing of the second balancing pipe 23. Figure 10As shown, the first end of the gas phase balance branch pipe 21 is connected between the eighth valve 808 and the liquefaction section 41. The eighth valve 808 and the ninth valve 809 are used to switch the compressor 42 and the liquefaction section 41 on and off. A seventh valve 807 is provided on the gas phase balance branch pipe 21, which is used to control the on and off of the gas phase balance branch pipe 21. In other embodiments, the first end of the gas phase balance branch pipe 21 can be connected to the second balance pipe 23 and connected between the second valve 802 and the working fluid outlet of the vaporization section 51. Alternatively, the first end of the gas phase balance branch pipe 21 can also be connected to the first balance pipe 22 at the position between the first valve 801 and the liquefaction section 41. Alternatively, the gas phase balance branch pipe 21 can also be connected between the first valve 801 and the first gas phase interface 12, or between the second valve 802 and the first gas phase interface 12. A sixth valve 806 is provided between the storage unit 10 and the liquefaction section 41 to control the flow between the working medium outlet of the liquefaction section 41 and the liquid phase interface 11 of the storage unit 10. A fourth valve 804 is provided between the storage unit 10 and the vaporization section 51 to control the flow between the liquid phase interface 11 of the storage unit 10 and the working medium inlet of the vaporization section 51. A third valve 803 is also provided at the liquid phase interface 11 to control its flow. A fifth valve 805 is provided on the filling and recovery branch pipe, one end of which is connected to the pipeline between the third valve 803, the fourth valve 804, and the sixth valve 806. The carbon dioxide tanker 30 has a first liquid phase control valve 811 and a first gas phase control valve 810.

[0072] The principle and process of working fluid filling are as follows:

[0073] (1.1) Check valve status. Confirm that the first valve 801, the second valve 802, the third valve 803, the fourth valve 804, the fifth valve 805, the sixth valve 806, the seventh valve 807, the eighth valve 808, the ninth valve 809, the first gas phase control valve 810, and the first liquid phase control valve 811 are all in the closed state.

[0074] (1.2) Connect the carbon dioxide tanker 30 to the liquid storage unit 10. Specifically, connect the first liquid phase control valve 811 to the cold test inlet of the heat exchange assembly 71, and connect the cold test outlet of the heat exchange assembly 71 to the fifth valve 805. Connect the first gas phase control valve 810 to the seventh valve 807. Temporary hoses can be used for the connections between the first liquid phase control valve 811 and the heat exchange assembly 71, the heat exchange assembly 71 and the fifth valve 805, and the first gas phase control valve 810 and the seventh valve 807, facilitating disassembly and assembly.

[0075] (1.3) Balance the pressure between the carbon dioxide tanker 30 and the liquid storage unit 10. Specifically, according to... Figure 10When connecting the components, open the first valve 801 (if the gas phase balance branch pipe 21 is connected between the second valve 802 and the working fluid outlet of the vaporization section 51, and the liquefaction section 41 does not need to adjust the pressure inside the storage unit 10, the first valve 801 can be kept closed, and the second valve 802 can be opened; if the gas phase balance branch pipe 21 is connected between the first valve 801 and the storage unit 10 and is located between the second valve 802 and the storage unit 10, and the liquefaction section 41 and the vaporization section 51 do not need to adjust the pressure of the storage unit 10, the first valve 801 and the second valve 802 can also be kept closed), slowly open the seventh valve 807, slowly and slightly open the first gas phase control valve 810, and detect the pressure rise rate of the storage unit 10 through the first pressure detection unit 14. The opening degree and speed of the first gas phase control valve 810 are controlled according to the degree to which the pressure rise rate of the storage unit 10 is less than 0.1 MPa / min. The pressure of the carbon dioxide tanker 30 is observed by the second pressure detection unit 32. When the pressure of the liquid storage unit 10 and the pressure of the carbon dioxide tanker 30 reach a balance (for example, the pressure difference is less than the preset pressure difference value, which is theoretically 0), the first gas phase control valve 810 is fully opened.

[0076] (1.4) Filling with liquid carbon dioxide. Specifically, open the third valve 803, open the fifth valve 805, and open the first liquid phase control valve 811. If delivery pressure is required, close the bypass control valve 75 and start the delivery pump 73 (see reference). Figure 11 This causes the outlet pressure of the transfer pump 73 to be 0.1 to 0.2 MPa higher than the internal pressure of the carbon dioxide tanker 30. The transfer pump 73 is used to transfer the liquid carbon dioxide in the carbon dioxide tanker 30 to the heat exchange component 71. After being heated by the heat exchange component 71, it is transported into the liquid storage unit 10.

[0077] (1.5) Filling temperature detection. Specifically, during the filling process, the temperature of the liquid carbon dioxide at the outlet of the heat exchange component 71 can be detected by the heat exchanger temperature detection unit 711, and the heat exchange component 71 can be adjusted to ensure that the temperature of the liquid carbon dioxide input into the liquid storage unit 10 reaches the preset filling temperature.

[0078] (1.6) Filling progress detection. Specifically, during the filling process, the liquid levels of the storage unit 10 and the carbon dioxide tanker 30 can be detected by the first liquid level detection unit 15 and the second liquid level detection unit 33. When the liquid level of a carbon dioxide tanker 30 is lower than the second preset liquid level, the delivery pump 73 is stopped, the first gas phase control valve 810, the first liquid phase control valve 811, the fifth valve 805, the seventh valve 807 are closed, and the heat exchange component 71 is closed, and the carbon dioxide tanker 30 is filled. Steps (1.2) to (1.6) are repeated for the next carbon dioxide tanker 30. For the first carbon dioxide tanker 30, that is, at the very beginning of the filling stage, the early stage of step (1.3) is, for example, by slowly opening the first gas phase control valve 810 to allow the gaseous carbon dioxide in the carbon dioxide tanker 30 to replace the original air in the storage unit 10. When the purity of the carbon dioxide in the storage unit 10 is detected to reach the preset purity value (e.g., 99%), the replacement is completed, and then the pressure in the storage unit 10 is made consistent with the pressure in the carbon dioxide tanker 30. Furthermore, during the filling stage, the liquefaction section 41 and the first valve 801, or the vaporization section 51 and the second valve 802 can be opened according to the pressure inside the liquid storage unit 10 to adjust the pressure inside the liquid storage unit 10 to the design pressure through the liquefaction section 41 or the vaporization section 51.

[0079] The principle and process of working fluid recovery are as follows:

[0080] (2.1) Check valve status. Confirm that the first valve 801, the second valve 802, the third valve 803, the fourth valve 804, the fifth valve 805, the sixth valve 806, the seventh valve 807, the eighth valve 808, the ninth valve 809, the first gas phase control valve 810, and the first liquid phase control valve 811 are all in the closed state.

[0081] (2.2) Connect the carbon dioxide tanker 30 to the liquid storage unit 10. Specifically, connect the first liquid phase control valve 811 to the fifth valve 805. Connect the first gas phase control valve 810 to the seventh valve 807. Temporary hoses can be used for the connections between the first liquid phase control valve 811 and the fifth valve 805, and between the first gas phase control valve 810 and the seventh valve 807, for easy assembly and disassembly.

[0082] (2.3) Balance the pressure between the carbon dioxide tanker 30 and the liquid storage unit 10. Specifically, according to... Figure 10When connecting the components, open the first valve 801 (if the gas phase balance branch pipe 21 is connected to the working fluid outlet of the second valve 802 and the vaporization section 51, keep the first valve 801 closed and open the second valve 802; if the gas phase balance branch pipe 21 is connected between the first valve 801 and the liquid storage unit 10 and is located between the second valve 802 and the liquid storage unit 10, then both the first valve 801 and the second valve 802 can be kept closed), slowly open the seventh valve 807, and slowly slightly open the first gas phase control valve 810. The pressure rise rate inside the carbon dioxide tanker 30 is detected by the second pressure detection unit 32. The opening degree and speed of the first gas phase control valve 810 are controlled to ensure that the pressure rise rate inside the carbon dioxide tanker 30 is less than 0.1 MPa / min. The pressure of the liquid storage unit 10 is observed by the first pressure detection unit 14. When the pressure of the liquid storage unit 10 and the pressure of the carbon dioxide tanker 30 reach equilibrium (for example, the pressure difference is less than the preset pressure difference value, which is theoretically 0), the first gas phase control valve 810 is fully opened.

[0083] (2.4) Recovering liquid carbon dioxide. Specifically, open the third valve 803, open the fifth valve 805, and open the first liquid phase control valve 811. If a delivery pressure is required, close the bypass control valve 75 and start the delivery pump 73 (refer to...). Figure 11 This causes the outlet pressure of the transfer pump 73 to be 0.1 to 0.2 MPa higher than the internal pressure of the carbon dioxide tanker 30, so that the liquid carbon dioxide in the storage unit 10 can be transferred to the carbon dioxide tanker 30 by the transfer pump 73.

[0084] (2.5) Recovery Progress Detection. Specifically, during the recovery period, the liquid levels of the storage unit 10 and the carbon dioxide tanker 30 can be detected by the first liquid level detection unit 15 and the second liquid level detection unit 33. When the liquid level of a carbon dioxide tanker 30 is higher than the fourth preset liquid level, the delivery pump 73 is stopped, and the first gas phase control valve 810, the first liquid phase control valve 811, the fifth valve 805, and the seventh valve 807 are closed, and the carbon dioxide tanker 30 has completed recovery. Steps (2.2) to (2.5) are repeated for the next carbon dioxide tanker 30. During the recovery phase, the opening and closing of other valves and the start and stop of the equipment can be controlled accordingly depending on whether the pressure in the storage unit 10 needs to be adjusted. For specific operation, please refer to the description of the aforementioned embodiment.

[0085] This invention also provides a working fluid filling method for a carbon dioxide energy storage system. Based on the working fluid filling and recovery assembly of the carbon dioxide energy storage system provided in any of the foregoing embodiments, the working fluid filling and recovery method includes:

[0086] S1: Connect the carbon dioxide tanker 30 to the gas phase balance branch pipe 21 to balance the pressure between the carbon dioxide tanker 30 and the liquid storage unit 10 through the gas phase balance branch pipe 21.

[0087] Step S2: Connect the carbon dioxide tanker 30 to the liquid phase interface 11.

[0088] Step S31 (filling step): During the filling stage, the carbon dioxide tanker 30 outputs liquid carbon dioxide to the storage unit 10.

[0089] Alternatively, step S32 (recovery step): During the recovery phase, the liquid storage unit 10 outputs liquid carbon dioxide to the carbon dioxide tanker 30.

[0090] While performing step S31, step S4 can also be performed: During the filling stage, the pressure regulating device 24 converts carbon dioxide into gas and liquid, so that the pressure in the liquid storage unit 10 reaches the design pressure.

[0091] In step S1, the top gas phase space of the storage unit 10 is connected to the carbon dioxide tanker 30 via the gas phase balance branch pipe 21 to balance the gas phase pressure between the carbon dioxide tanker 30 and the storage unit 10. This ensures smooth liquid flow in step S31 or S32, enabling rapid filling or recovery of carbon dioxide. In step S4, the pressure regulating device 24 allows the storage unit 10 to be filled with liquid carbon dioxide at the designed pressure. This device is adaptable to carbon dioxide tankers 30 with different transport pressures and maintains pressure balance within the storage unit 10, ensuring rapid filling.

[0092] In some embodiments, the working fluid filling and recovery assembly further includes, for example, a heat exchange assembly 71. Step S2 specifically includes connecting the carbon dioxide tanker 30 to the liquid phase interface 11 via the heat exchange assembly 71. Step S31 specifically involves the carbon dioxide tanker 30 outputting liquid carbon dioxide to the heat exchange assembly 71, which then heats the liquid carbon dioxide to a preset filling temperature before outputting it to the storage unit 10. Currently, due to lower cryogenic transportation costs, the liquid carbon dioxide transported by the carbon dioxide tanker 30 is typically as low as -40°C. The heat exchange assembly 71 can, for example, heat the liquid carbon dioxide to approximately -20 to 20°C to match the normal operating temperature of the storage unit 10 and related pipelines and valves.

[0093] In some embodiments, the working fluid filling and recovery assembly further includes, for example, a pressure detection device and a first gas phase control valve 810. Step S1 specifically includes the first gas phase control valve 810 operating according to the detection results of the first pressure detection unit 14 and the second pressure detection unit 32. Specifically, the opening degree of the first gas phase control valve 810 is controlled according to the detection results of the first pressure detection unit 14 and the second pressure detection unit 32. Through the above control, the pressure status of the liquid storage unit 10 and the carbon dioxide tanker 30 can be more accurately determined, and better operation can be facilitated.

[0094] Other specific steps of the working fluid filling and recycling method provided in this embodiment of the invention can be referred to the description of the operation process and principle in the aforementioned embodiments of the working fluid filling and recycling component. This working fluid filling and recycling method has the same beneficial effects as the aforementioned embodiments, and will not be repeated here.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A working fluid filling and recovery assembly for a carbon dioxide gas-liquid phase change energy storage system, characterized in that, include: A liquid storage unit for storing liquid carbon dioxide and gaseous carbon dioxide, the liquid storage unit having a liquid phase interface and a first gas phase interface at the top of the liquid storage unit; the liquid storage unit is used to receive the liquid carbon dioxide from the carbon dioxide tanker through the liquid phase interface during the filling stage or to output the liquid carbon dioxide to the carbon dioxide tanker through the liquid phase interface during the recovery stage. The pressure balancing unit includes a pressure regulating device and a gas phase balancing branch pipe. The pressure regulating device is connected to the liquid phase interface and the first gas phase interface, respectively. The pressure regulating device is used to perform gas-liquid conversion of carbon dioxide during the filling stage to make the pressure in the liquid storage unit reach the design pressure. The first end of the gas phase balancing branch pipe is connected to the first gas phase interface, and the second end of the gas phase balancing branch pipe is used to connect to the carbon dioxide tank truck. The gaseous carbon dioxide can flow between the liquid storage unit and the carbon dioxide tank truck through the gas phase balancing branch pipe to balance the pressure between the liquid storage unit and the carbon dioxide tank truck. Wherein, the design pressure is the energy storage pressure of the carbon dioxide gas-liquid phase change energy storage system; The pressure regulating device includes a liquefaction section and a vaporization section. The working fluid outlet of the liquefaction section is connected to the liquid phase interface, and the working fluid side of the liquefaction section is connected to the first gas phase interface. The liquefaction section is used to convert gaseous carbon dioxide into liquid carbon dioxide and output the liquid carbon dioxide to the storage unit when the transportation pressure of the carbon dioxide tanker is greater than the design pressure during the filling stage, so as to reduce the pressure in the storage unit to the design pressure during the filling stage. The working fluid inlet of the vaporization section is connected to the liquid phase interface, and the working fluid outlet of the vaporization section is connected to the first gas phase interface. The vaporization section is used to convert the liquid carbon dioxide gas output from the storage unit into gaseous carbon dioxide and output the gaseous carbon dioxide to the storage unit when the transportation pressure of the carbon dioxide tanker is less than the design pressure during the filling stage, so as to increase the pressure in the storage unit to the design pressure during the filling stage.

2. The working fluid filling and recovery assembly of the carbon dioxide gas-liquid phase change energy storage system as described in claim 1, characterized in that, The pressure balancing unit further includes: a first balancing pipe, connected between the first gas phase interface and the liquefaction section; The first end of the gas phase balance branch is connected to the first balance pipe; Alternatively, the first end of the gas phase balance branch pipe can be connected to the working fluid inlet of the liquefaction section.

3. The working fluid filling and recovery assembly of the carbon dioxide gas-liquid phase change energy storage system as described in claim 1, characterized in that, The pressure balancing unit further includes: a second balancing pipe, which is connected between the working fluid outlet of the vaporization section and the first gas phase interface; the first end of the gas phase balancing branch pipe is connected to the second balancing pipe.

4. The working fluid filling and recovery assembly of the carbon dioxide gas-liquid phase change energy storage system as described in claim 1, characterized in that, It also includes a heat exchange component, which is used to heat the liquid carbon dioxide output from the carbon dioxide tanker to a preset filling temperature during the filling stage and output it to the storage unit.

5. The working fluid filling and recovery assembly of the carbon dioxide gas-liquid phase change energy storage system as described in claim 1, characterized in that, Also includes: A first transmission pipeline, with its two opposite ends connected to the liquid storage unit and the carbon dioxide tanker, respectively; A delivery pump is installed on the first transmission pipeline; A second transmission pipeline is connected in parallel with the delivery pump, and a bypass control valve is installed on the second transmission pipeline.

6. The working fluid filling and recovery assembly of the carbon dioxide gas-liquid phase change energy storage system as described in claim 5, characterized in that, The transfer pump is a bidirectional pump, which is used to make a first turn during the filling stage to transport the liquid carbon dioxide output from the carbon dioxide tanker to the storage unit via the first transfer pipeline; and to make a second turn during the recovery stage to transport the liquid carbon dioxide in the storage unit to the carbon dioxide tanker via the first transfer pipeline. The first steering and the second steering are opposite.

7. The working fluid filling and recovery assembly of the carbon dioxide gas-liquid phase change energy storage system as described in any one of claims 1 to 6, characterized in that, It also includes the carbon dioxide tanker truck, which is used to provide liquid carbon dioxide to the storage unit during the filling stage or to receive and store the liquid carbon dioxide output by the storage unit during the recovery stage; the top of the carbon dioxide tanker truck has a second gas phase interface, and the second end of the gas phase balance branch pipe is connected to the second gas phase interface.

8. A method for filling and recovering the working fluid in a carbon dioxide gas-liquid phase change energy storage system, characterized in that, Based on the working fluid filling and recovery assembly of the carbon dioxide gas-liquid phase change energy storage system as described in any one of claims 1 to 7, the working fluid filling and recovery method includes: Connect the carbon dioxide tanker to the gas phase balance branch pipe, and balance the pressure between the carbon dioxide tanker and the liquid storage unit through the gas phase balance branch pipe. Connect the carbon dioxide tanker to the liquid phase interface; During the filling stage, the carbon dioxide tanker truck outputs the liquid carbon dioxide to the storage unit; or during the recovery stage, the storage unit outputs the liquid carbon dioxide to the carbon dioxide tanker truck. During the filling stage, the pressure regulating device converts carbon dioxide into gas and liquid, so that the pressure in the storage unit reaches the design pressure. Specifically, when the transport pressure of the carbon dioxide tanker is greater than or equal to the design pressure, the liquefaction unit converts the gaseous carbon dioxide into liquid carbon dioxide and outputs the liquid carbon dioxide to the storage unit to reduce the pressure in the storage unit to the design pressure. When the transport pressure of the carbon dioxide tanker is less than the design pressure, the vaporization unit converts the liquid carbon dioxide output from the storage unit into gaseous carbon dioxide and outputs the gaseous carbon dioxide to the storage unit to increase the pressure in the storage unit to the design pressure.

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