A supercritical carbon dioxide coupled molten salt energy storage power generation and steam supply system and method

Abstract

The application discloses a supercritical carbon dioxide coupling molten salt energy storage power generation and steam supply system and method, wherein a liquid outlet of a carbon dioxide liquid low-temperature ball storage tank is connected with an inlet of a heat exchange pipe in a carbon dioxide exhaust pipe molten salt storage tank through a low-temperature high-pressure plunger pump, a carbon dioxide starting electric heater, a pipe side of a carbon dioxide low-pressure heater and an electromagnetic heater; an outlet of the heat exchange pipe in the carbon dioxide exhaust pipe molten salt storage tank is connected with an inlet of a carbon dioxide power generation turbine through a first carbon dioxide buffer device; and an outlet of the carbon dioxide power generation turbine is connected with an inlet of a carbon dioxide gas-liquid separator through a pipe side of a steam generator, a pipe side of a carbon dioxide waste heat recovery device and a pipe side of a plate cooler. The system and method have the characteristics of high energy storage flexibility, long service life, economy and environmental protection, small energy storage heat loss, small influence of bad environment, convenient maintenance and easy management in safety.

Description

Technical Field

[0001] This invention belongs to the field of novel thermal mass storage technology, and relates to a system and method for supercritical carbon dioxide coupled molten salt energy storage power generation and steam supply. Background Technology

[0002] With the continuous implementation of my country's new power system construction, the installed capacity of new energy sources such as wind power and photovoltaics has continued to expand. Currently, the total installed capacity of new energy has surpassed that of traditional thermal power units, becoming the main power source for the power grid. Wind and solar energy are typical intermittent renewable energy sources, and their power generation inherently suffers from significant intermittency, volatility, and randomness: photovoltaic power generation is limited by the duration and intensity of sunshine, with high peak output and ample surplus power during the day, but no power generation at night; wind power output is affected by factors such as wind speed, wind direction, and climate, resulting in large fluctuations and low accuracy in output prediction. After large-scale integration of new energy power into the grid, the peak-valley difference in grid load continues to widen, the problem of temporal and spatial mismatch between power supply and demand becomes increasingly prominent, wind and solar curtailment occurs frequently, and the difficulty of local consumption and grid integration of new energy has increased significantly, seriously affecting the safe and stable operation of the new power system and restricting the efficient and large-scale utilization of new energy resources.

[0003] To mitigate fluctuations in renewable energy output and maintain a dynamic balance between power grid supply and demand, the existing power system primarily relies on traditional thermal power units for peak shaving, frequency regulation, and backup regulation. During the daytime off-peak hours when renewable energy generation is high, electricity prices are low, requiring thermal power units to reduce load and conduct deep peak shaving operations. At night and during peak hours, electricity prices are high, necessitating rapid load increases to fill power supply gaps. This deep load-shifting operation mode places stringent requirements on the load adjustment range, load shifting response rate, and minimum stable fuel output of thermal power units. Long-term deep peak shaving and frequent load shifting of thermal power units not only significantly increases coal consumption and reduces unit operating economics but also easily leads to unstable furnace combustion, accelerated wear of heating surfaces, and accelerated wear of auxiliary equipment, significantly increasing equipment maintenance costs and unit failure risks. The flexible adjustment capabilities of traditional thermal power are no longer sufficient to meet the grid operation and regulation needs under a high proportion of renewable energy integration.

[0004] Currently, electrochemical energy storage is the mainstream technology for large-scale application in the power energy storage field. However, this technology has significant shortcomings in long-duration, large-capacity, and high-safety-level grid peak-shaving energy storage scenarios. Electrochemical energy storage has a short cycle life, and the battery degradation rate is rapid under long-term frequent charge-discharge conditions, resulting in poor overall economic efficiency throughout its life cycle. At the same time, battery modules are prone to thermal runaway, posing safety hazards such as fire and explosion, making the safe operation and maintenance and risk management of large-scale energy storage power stations extremely difficult. In addition, electrochemical energy storage generally suffers from limited storage time, poor low-temperature adaptability, and weak environmental interference resistance, which cannot meet the all-weather, long-cycle, and large-capacity energy storage peak-shaving operation requirements of new power systems, thus significantly limiting its application scenarios.

[0005] In response to the current industry situation characterized by drastic fluctuations in new energy grid connection, significant pressure on thermal power peak shaving, substantial shortcomings in electrochemical energy storage technology, and insufficient overall adaptability of existing molten salt energy storage devices, conventional molten salt energy storage equipment on the market generally suffers from drawbacks such as poor energy storage regulation flexibility, short lifespan, large heat loss from the tank, weak adaptability to harsh operating environments, inconvenient disassembly and maintenance, and an imperfect safety management system. These shortcomings prevent the full realization of the technological advantages and application value of molten salt for long-term energy storage. Therefore, there is an urgent need to develop a new type of molten salt energy storage device that possesses high flexibility, long service life, economic efficiency, environmental friendliness, low heat loss, strong environmental adaptability, convenient maintenance, and simple safety management to meet the urgent needs for long-term energy storage and flexible peak shaving in a high-proportion new energy power system. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a system and method for supercritical carbon dioxide coupled molten salt energy storage power generation and steam supply. This system and method have the characteristics of high energy storage flexibility, long life cycle, economic and environmental protection, low energy storage heat loss, less affected by harsh environment, convenient maintenance, and easy management in terms of safety.

[0007] To achieve the above objectives, this invention discloses a supercritical carbon dioxide coupled molten salt energy storage power generation and steam supply system, including a liquid carbon dioxide cryogenic spherical storage tank, a carbon dioxide piped molten salt storage tank, a carbon dioxide power generation turbine, a carbon dioxide gas-liquid separator, a refrigerator, and a filling port. The liquid outlet of the carbon dioxide liquid cryogenic spherical storage tank is connected to the inlet of the heat exchange tube in the carbon dioxide pipeline molten salt storage tank via a cryogenic high-pressure plunger pump, a carbon dioxide starting electric heater, the tube side of the carbon dioxide low-pressure heater, and an electromagnetic heater. The outlet of the heat exchange tube in the carbon dioxide pipeline molten salt storage tank is connected to the inlet of the carbon dioxide generator turbine via a first carbon dioxide buffer device. The outlet of the carbon dioxide generator turbine is connected to the inlet of the carbon dioxide gas-liquid separator via the tube side of the steam generator, the tube side of the carbon dioxide waste heat recovery unit, and the tube side of the plate cooler. The gas outlet of the carbon dioxide gas-liquid separator is connected to the inlet of the refrigeration unit. The filling port is connected to the inlet of the refrigeration unit. The outlet of the refrigeration unit is connected to the inlet of the carbon dioxide liquid cryogenic spherical storage tank. The liquid outlet of the carbon dioxide gas-liquid separator is connected to the inlet of the cryogenic high-pressure plunger pump.

[0008] Furthermore, the carbon dioxide power generation turbine is connected in parallel with a carbon dioxide pressure regulating valve.

[0009] Furthermore, the liquid outlet of the carbon dioxide gas-liquid separator is connected to the inlet of the cryogenic high-pressure plunger pump via a second carbon dioxide buffer device.

[0010] Furthermore, it also includes steam pipes, low-temperature feedwater pipes, and high-temperature steam pipes. The outlet of the steam pipes is connected to the pipe-side inlet of the low-pressure carbon dioxide heater. The pipe-side outlet of the low-pressure carbon dioxide heater is connected to the inlet of the recovery pump. The outlet of the recovery pump is connected to the shell-side inlet of the steam generator. The outlet of the low-temperature feedwater pipes is connected to the shell-side inlet of the carbon dioxide waste heat recovery unit. The shell-side outlet of the carbon dioxide waste heat recovery unit is connected to the shell-side inlet of the steam generator. The shell-side outlet of the steam generator is connected to the high-temperature steam pipes.

[0011] Furthermore, the exterior of the liquid carbon dioxide cryogenic sphere storage tank is equipped with cooling pipes for cooling and a layer of insulation material.

[0012] Furthermore, the carbon dioxide level in the carbon dioxide cryogenic sphere storage tank shall not exceed 1 / 3 of the tank's volume.

[0013] Furthermore, check valves are installed on all the relevant pipelines connected to the carbon dioxide liquid cryogenic sphere storage tank.

[0014] Furthermore, a check valve is installed on the outlet pipe of the cryogenic high-pressure plunger pump.

[0015] Furthermore, the liquid level outlet of the carbon dioxide gas-liquid separator is equipped with a 361 valve.

[0016] This invention discloses a method for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply, comprising the following steps: Liquid carbon dioxide output from the cryogenic spherical storage tank is heated by a cryogenic high-pressure plunger pump into a carbon dioxide starter electric heater, then into a low-pressure carbon dioxide heater, then into an electromagnetic heater, then into a molten salt storage tank for heat release, and finally into a carbon dioxide generator turbine to perform work. The exhaust gas from the carbon dioxide generator turbine enters a steam generator for heat release, then into a carbon dioxide waste heat recovery unit for heat release, and then into a plate cooler for cooling before entering a carbon dioxide gas-liquid separator for gas-liquid separation. The separated gas enters the cryogenic spherical storage tank via a refrigeration unit, while the separated liquid enters the cryogenic high-pressure plunger pump.

[0017] The present invention has the following beneficial effects: The supercritical carbon dioxide coupled molten salt energy storage power generation and steam supply system and method described in this invention, in specific operation, uses a closed Brayton cycle as the core, coupled with molten salt energy storage to reduce the fluidity of the molten salt. It converts abandoned electricity and off-peak electricity into high-temperature steam, which participates in deep peak shaving of thermal power units and generates electricity externally through energy storage, maintaining grid stability. It features high energy storage flexibility, long lifespan, economic and environmental friendliness, low heat loss from energy storage, minimal impact from harsh environments, convenient maintenance, and easy management in terms of safety, making it highly practical. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a structural diagram of the present invention.

[0020] Among them, 1 is a liquid carbon dioxide cryogenic spherical storage tank, 2 is a cryogenic high-pressure plunger pump, 3 is a carbon dioxide start-up electric heater, 4 is a carbon dioxide low-pressure heater, 5 is an electromagnetic heater, 6 is a carbon dioxide pipe molten salt storage tank, 7 is a carbon dioxide power generation turbine, 8 is a steam generator, 9 is a carbon dioxide waste heat recovery unit, 10 is a plate cooler, 11 is a carbon dioxide gas-liquid separator, 12 is a refrigerator, 13 is a recovery pump, 141 is a first carbon dioxide buffer device, 142 is a second carbon dioxide buffer device, and 15 is a carbon dioxide pressure regulating valve. Detailed Implementation

[0021] 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, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0023] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0024] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0025] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0026] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0028] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0029] refer to Figure 1 The supercritical carbon dioxide coupled molten salt energy storage power generation and steam supply system of the present invention includes a carbon dioxide liquid cryogenic spherical storage tank 1, a cryogenic high-pressure plunger pump 2, a carbon dioxide start-up electric heater 3, a carbon dioxide low-pressure heater 4, an electromagnetic heater 5, a carbon dioxide pipe molten salt storage tank 6, a carbon dioxide power generation turbine 7, a steam generator 8, a carbon dioxide waste heat recovery unit 9, a plate cooler 10, a carbon dioxide gas-liquid separator 11, a refrigerator 12, a recovery pump 13, a first carbon dioxide buffer device 141, a second carbon dioxide buffer device 142, and a carbon dioxide pressure regulating valve 15. The liquid outlet of the carbon dioxide liquid cryogenic spherical storage tank 1 is connected to the inlet of the carbon dioxide starting electric heater 3 via the cryogenic high-pressure plunger pump 2. The outlet of the carbon dioxide starting electric heater 3 is connected to the pipe-side inlet of the carbon dioxide low-pressure heater 4. The pipe-side outlet of the carbon dioxide low-pressure heater 4 is connected to the inlet of the electromagnetic heater 5. The outlet of the electromagnetic heater 5 is connected to the inlet of the heat exchange tube in the carbon dioxide pipe molten salt storage tank 6. The outlet of the heat exchange tube in the carbon dioxide pipe molten salt storage tank 6 is connected to the inlet of the first carbon dioxide buffer device 141. The outlet of the first carbon dioxide buffer device 141 is connected to the inlet of the carbon dioxide power generation turbine 7. The outlet of the carbon dioxide power generation turbine 7 is connected to the pipe-side inlet of the steam generator 8. A carbon dioxide pressure regulating valve 15 is connected in parallel. The pipe-side outlet of the steam generator 8 is connected to the pipe-side inlet of the carbon dioxide waste heat recovery unit 9. The pipe-side outlet of the carbon dioxide waste heat recovery unit 9 is connected to the pipe-side inlet of the plate cooler 10. The pipe-side outlet of the plate cooler 10 is connected to the inlet of the carbon dioxide gas-liquid separator 11. The gas outlet of the carbon dioxide gas-liquid separator 11 is connected to the inlet of the refrigerator 12. The filling port is connected to the inlet of the refrigerator 12. The outlet of the refrigerator 12 is connected to the inlet of the carbon dioxide liquid cryogenic ball storage tank 1. The liquid outlet of the carbon dioxide gas-liquid separator 11 is connected to the inlet of the second carbon dioxide buffer device 142. The outlet of the second carbon dioxide buffer device 142 is connected to the inlet of the cryogenic high-pressure plunger pump 2. The outlet of the steam pipe is connected to the pipe-side inlet of the low-pressure carbon dioxide heater 4. The pipe-side outlet of the low-pressure carbon dioxide heater 4 is connected to the inlet of the recovery pump 13. The outlet of the recovery pump 13 is connected to the shell-side inlet of the steam generator 8. The outlet of the low-temperature feedwater pipe is connected to the shell-side inlet of the carbon dioxide waste heat recovery unit 9. The shell-side outlet of the carbon dioxide waste heat recovery unit 9 is connected to the shell-side inlet of the steam generator 8. The shell-side outlet of the steam generator 8 is connected to the high-temperature steam pipe.

[0030] The method for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply according to the present invention includes the following steps: Liquid carbon dioxide output from the cryogenic carbon dioxide storage tank 1 is heated by the cryogenic high-pressure plunger pump 2, then heated by the carbon dioxide start-up electric heater 3, then heated by the carbon dioxide low-pressure heater 4, then heated by the electromagnetic heater 5, then released heat in the carbon dioxide pipe molten salt storage tank 6, and then enters the carbon dioxide generator turbine 7 to do work after passing through the first carbon dioxide buffer device 141. The exhaust gas from the carbon dioxide generator turbine 7 enters the steam generator 8 to release heat, then enters the carbon dioxide waste heat recovery unit 9 to release heat, and then enters the plate cooler 10 to cool before entering the carbon dioxide gas-liquid separator 11 for gas-liquid separation. The separated gas enters the cryogenic carbon dioxide storage tank 1 through the refrigerator 12, and the separated liquid enters the cryogenic high-pressure plunger pump 2 through the second carbon dioxide buffer device 142.

[0031] Specifically, this invention converts surplus electricity and off-peak electricity prices into thermal energy storage, and continuously converts the thermal energy into high-temperature steam or electricity for external power supply, high-temperature steam supply, or deep peak shaving of steam supply to the generating unit. Carbon dioxide is captured by the CCUS carbon capture system of the thermal power unit and transported to a cryogenic liquid carbon dioxide storage tank 1 for storage. The stored cryogenic carbon dioxide is pressurized to 25 MPa by a cryogenic high-pressure plunger pump 2. The pressurized carbon dioxide is then heated by a carbon dioxide starter electric heater 3 to become dense phase carbon dioxide. The dense phase carbon dioxide is further heated by a low-pressure carbon dioxide heater 4 to become supercritical carbon dioxide. The heated supercritical carbon dioxide is then heated again by an electromagnetic heater 5 to 585°C, reaching the high-temperature supercritical state, and transported to a carbon dioxide pipe molten salt storage tank 6 for thermal energy storage and to raise the molten salt temperature. After heat exchange with the molten salt, the supercritical carbon dioxide enters a first carbon dioxide buffer device 141 for pressure and temperature buffering. After buffering, it supplies power externally through a carbon dioxide generator turbine 7, and the carbon dioxide pressure decreases after passing through the carbon dioxide generator turbine 7. Alternatively, the pressure can be reduced via the carbon dioxide pressure regulating valve 15 after buffering. After completing the work and the pressure reduction via the carbon dioxide pressure regulating valve 15, the carbon dioxide enters the steam generator 8 for heat exchange again, vaporizing the high-temperature feedwater into high-temperature, high-pressure steam. The heat-exchanged carbon dioxide then passes through the carbon dioxide waste heat recovery unit 9 for heat exchange with the feedwater again, raising the feedwater temperature once more. Finally, the carbon dioxide passes through the plate cooler 10 to raise the temperature of the low-temperature feedwater, reducing the carbon dioxide temperature to approximately 10°C and the pressure to approximately 5 MPa, before being transported to the carbon dioxide gas-liquid separator 11. The carbon dioxide gas-liquid separator 11 divides into two paths: one path enters the low-temperature, high-pressure plunger pump 2 for recirculation and energy storage, and the other path passes through the chiller 12 to maintain the pressure balance inside the carbon dioxide liquid low-temperature spherical storage tank 1. The low-temperature feedwater is raised to 40°C by the plate cooler 10, then flows through the carbon dioxide waste heat recovery unit 9 for further heating, and finally vaporizes into high-temperature steam of the corresponding quality by the steam generator 8. After passing through the low-pressure carbon dioxide heater 4, the steam is cooled down and becomes liquid high-temperature water. The liquid recycled water is then transported to the steam generator 8 by the recovery pump 13.

[0032] The carbon dioxide in the cryogenic liquid carbon dioxide spherical storage tank 1 is stored under cryogenic conditions, and the operating pressure of the carbon dioxide cryogenic liquid carbon dioxide spherical storage tank 1 is 3.5MPa~4MPa. The cryogenic high-pressure plunger pump 2 maintains the carbon dioxide pressure at the pump outlet at 25MPa. The main function of the carbon dioxide start-up electric heater 3 and the carbon dioxide low-pressure heater 4 is to convert carbon dioxide from a liquid state to a supercritical state. The plate cooler 10 converts supercritical carbon dioxide into liquid carbon dioxide. The main function of the electromagnetic heater 5 is to convert electrical energy into heat energy which is carried away by supercritical carbon dioxide. The outlet temperature of the electromagnetic heater 5 is 585℃. The carbon dioxide pipe molten salt storage tank 6 and the supercritical carbon dioxide both serve as heat storage media. The carbon dioxide power generation turbine 7 converts high-temperature and high-pressure supercritical carbon dioxide into medium-temperature and medium-pressure supercritical carbon dioxide. The steam generator 8 converts medium-temperature and medium-pressure supercritical carbon dioxide into low-temperature and medium-temperature supercritical carbon dioxide and transfers the heat to the water-steam system to continuously supply steam. The carbon dioxide waste heat recovery unit 9 heats the cryogenic feedwater, further reducing the temperature of the supercritical carbon dioxide. The carbon dioxide gas-liquid separator 11 mainly balances the internal pressure of the carbon dioxide cryogenic liquid spherical storage tank 1.

[0033] In this embodiment, the external structure of the carbon dioxide liquid cryogenic spherical storage tank 1 is equipped with cooling pipes for cooling and a layer of insulation material. When the system is operating in a closed loop, the carbon dioxide level inside the carbon dioxide liquid cryogenic spherical storage tank 1 does not exceed 1 / 3 of its volume. The carbon dioxide liquid cryogenic spherical storage tanks 1 are small in volume and arranged in an array. Check valves are installed on all pipes connected to the carbon dioxide liquid cryogenic spherical storage tank 1.

[0034] In this embodiment, a check valve is installed on the outlet pipe of the cryogenic high-pressure plunger pump 2. The pressure of the outlet pipe is 25MPa. The inlet pipe is divided into two paths: one path is connected to the carbon dioxide liquid cryogenic sphere storage tank 1 in the cold state during startup, and the other path is connected to the second carbon dioxide buffer device 142 in the hot state.

[0035] In this embodiment, the electromagnetic heater 5 is a 10KV high-power variable frequency high-voltage electromagnetic heater. The temperature of supercritical carbon dioxide can reach ℃ after being heated by the electromagnetic heater 5. The electromagnetic heater 5 is arranged horizontally.

[0036] In this embodiment, the carbon dioxide pipe molten salt storage tank 6 is a large-volume cylindrical vertical tank. The tank contains carbon dioxide heat exchange and storage pipes, with both the inlet and outlet of the carbon dioxide pipes converging into the carbon dioxide pipe molten salt storage tank 6. A large plate beam steel structure is installed at the top of the carbon dioxide pipe molten salt storage tank 6. This steel structure is suspended to support the carbon dioxide pipe collection box. The horizontal cross-section of the carbon dioxide pipes is triangular, and a limit device is installed at the bottom of the carbon dioxide pipes, welded to the bottom plate of the carbon dioxide pipe molten salt storage tank 6. A sealed, insulated cover is installed between the carbon dioxide pipe molten salt storage tank 6 and the large plate beam steel structure, with the carbon dioxide collection box located inside the insulated cover.

[0037] In this embodiment, the carbon dioxide power generation turbine 7 converts high-pressure supercritical carbon dioxide into medium-pressure supercritical carbon dioxide after performing work. The carbon dioxide power generation turbine 7 is equipped with a bypass carbon dioxide pipeline, which is equipped with a regulating valve. The bypass carbon dioxide pipeline is used when the temperature of the carbon dioxide discharge pipe molten salt storage tank 6 does not exceed 400°C, or when a large amount of steam is required externally.

[0038] In this embodiment, a valve 361 is arranged at the liquid level outlet of the carbon dioxide gas-liquid separator 11 for liquid level regulation. A second carbon dioxide buffer device 142 is installed downstream of the valve 361. A mechanical ventilation device is installed around the carbon dioxide gas-liquid separator 11, and the second carbon dioxide buffer device 142 is installed on the pipeline downstream of the valve 361. The gas side of the carbon dioxide gas-liquid separator 11 is connected to the carbon dioxide liquid cryogenic spherical storage tank 1 through a refrigerator 12.

[0039] In this embodiment, the low-temperature feedwater passes sequentially through a plate cooler 10, a carbon dioxide waste heat recovery unit 9, and a steam generator 8 to supply steam to the outside.

[0040] In this embodiment, steam needs to be supplied to the outside during both energy storage and heat release processes. As the temperature of the carbon dioxide exhaust pipe molten salt storage tank 6 increases, the external steam supply also increases. To ensure stable steam supply requirements, a steam matching device can be set up to adjust the external steam supply temperature.

[0041] This invention uses a closed-loop Brayton cycle as its core, coupled with molten salt energy storage, reducing the fluidity of the molten salt. It converts surplus electricity and off-peak electricity into high-temperature steam, which participates in deep peak shaving of thermal power units and generates electricity externally through energy storage, maintaining grid stability. Utilizing the boiler tail gas carbon dioxide CCUS (Carbon Capture-by-US) process, it can help the country achieve its carbon neutrality goal sooner. The entire system significantly reduces water waste and is worthy of promotion in arid regions. The entire system uses the 10kV voltage level commonly found in thermal power plants, reducing voltage level conversions and improving safety. The electromagnetic heater is slightly more efficient than the resistance heater, improving resource utilization efficiency.

[0042] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0043] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0044] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A system for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply, characterized in that, It includes a liquid carbon dioxide cryogenic spherical storage tank (1), a carbon dioxide piped molten salt storage tank (6), a carbon dioxide power generation turbine (7), a carbon dioxide gas-liquid separator (11), a refrigerator (12), and a filling port; The liquid outlet of the carbon dioxide liquid cryogenic spherical storage tank (1) is connected to the inlet of the heat exchange tube in the carbon dioxide pipe molten salt storage tank (6) via the pipe side of the cryogenic high-pressure plunger pump (2), the carbon dioxide start-up electric heater (3), the carbon dioxide low-pressure heater (4), and the electromagnetic heater (5). The outlet of the heat exchange tube in the carbon dioxide pipe molten salt storage tank (6) is connected to the inlet of the carbon dioxide power generation turbine (7) via the first carbon dioxide buffer device (141). The outlet of the carbon dioxide power generation turbine (7) is connected to the steam generator (8). The pipe side of the carbon dioxide waste heat recovery unit (9) and the pipe side of the plate cooler (10) are connected to the inlet of the carbon dioxide gas-liquid separator (11). The gas outlet of the carbon dioxide gas-liquid separator (11) is connected to the inlet of the refrigerator (12). The filling port is connected to the inlet of the refrigerator (12). The outlet of the refrigerator (12) is connected to the inlet of the carbon dioxide liquid cryogenic ball storage tank (1). The liquid outlet of the carbon dioxide gas-liquid separator (11) is connected to the inlet of the cryogenic high-pressure plunger pump (2).

2. The system for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply according to claim 1, characterized in that, The carbon dioxide power generation turbine (7) is connected in parallel to a carbon dioxide pressure regulating valve (15).

3. The system for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply according to claim 1, characterized in that, The liquid outlet of the carbon dioxide gas-liquid separator (11) is connected to the inlet of the cryogenic high-pressure plunger pump (2) via the second carbon dioxide buffer device (142).

4. The system for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply according to claim 1, characterized in that, It also includes a steam pipe, a low-temperature water supply pipe and a high-temperature steam pipe. The outlet of the steam pipe is connected to the pipe-side inlet of the low-pressure carbon dioxide heater (4). The pipe-side outlet of the low-pressure carbon dioxide heater (4) is connected to the inlet of the recovery pump (13). The outlet of the recovery pump (13) is connected to the shell-side inlet of the steam generator (8). The outlet of the low-temperature water supply pipe is connected to the shell-side inlet of the carbon dioxide waste heat recovery unit (9). The shell-side outlet of the carbon dioxide waste heat recovery unit (9) is connected to the shell-side inlet of the steam generator (8). The shell-side outlet of the steam generator (8) is connected to the high-temperature steam pipe.

5. The system for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply according to claim 1, characterized in that, The external part of the liquid carbon dioxide cryogenic spherical storage tank (1) is equipped with cooling pipes for cooling and a layer of insulation material.

6. The system for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply according to claim 1, characterized in that, The carbon dioxide level in the carbon dioxide liquid cryogenic sphere storage tank (1) is not greater than 1 / 3 of the volume of the carbon dioxide liquid cryogenic sphere storage tank (1).

7. The system for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply according to claim 1, characterized in that, Check valves are installed on all the relevant pipelines connected to the carbon dioxide liquid cryogenic sphere storage tank (1).

8. The system for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply according to claim 1, characterized in that, A check valve is installed on the outlet pipe of the low-temperature high-pressure plunger pump (2).

9. The system for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply according to claim 1, characterized in that, The liquid level outlet of the carbon dioxide gas-liquid separator (11) is equipped with a 361 valve.

10. A method for supercritical carbon dioxide coupled with molten salt energy storage for power generation and steam supply, characterized in that, Includes the following steps: Liquid carbon dioxide output from the liquid carbon dioxide cryogenic sphere storage tank (1) is heated by the cryogenic high-pressure plunger pump (2) and then heated by the carbon dioxide start-up electric heater (3), then heated by the carbon dioxide low-pressure heater (4), then heated by the electromagnetic heater (5), then heated by the carbon dioxide pipe molten salt storage tank (6), and then heated by the carbon dioxide generator turbine (7). The exhaust gas from the carbon dioxide generator turbine (7) is heated by the steam generator (8), then heated by the carbon dioxide waste heat recovery unit (9), and then cooled by the plate cooler (10) before entering the carbon dioxide gas-liquid separator (11) for gas-liquid separation. The separated gas enters the liquid carbon dioxide cryogenic sphere storage tank (1) through the refrigerator (12), and the separated liquid enters the cryogenic high-pressure plunger pump (2).

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