Thermal battery coupled thermal power energy storage system based on medium pressure cylinder extraction steam driving

Abstract

This invention discloses a thermal battery-coupled thermal power energy storage system driven by steam extraction from a medium-pressure cylinder, comprising: a thermal power unit module, a heat pump module, a steam extraction drive unit, and a flow regulation and control module. The high-temperature compressor of the heat pump module is used to compress the circulating working fluid; the steam inlet of the independent turbine of the steam extraction drive unit is connected to the steam outlet of the intermediate-pressure cylinder of the turbine, and the output shaft of the independent turbine is connected to the high-temperature compressor to drive it; a first regulating valve and a second regulating valve are used to control the on / off connection between the steam outlet of the intermediate-pressure cylinder of the turbine and the steam inlet of the low-pressure cylinder of the turbine, and the steam inlet of the independent turbine, respectively. According to the thermal battery-coupled thermal power energy storage system driven by steam extraction from a medium-pressure cylinder of this invention, the high-temperature compressor can be directly driven by steam extraction from the turbine, replacing the traditional electrically driven compression heat pump, thus better realizing energy cascade utilization and significantly reducing the power consumption of the heat pump module.

Description

Technical Field

[0001] This invention relates to the field of flexible peak shaving and thermal energy storage coupling technology for thermal power units, and in particular to a thermal battery coupled thermal power energy storage system based on steam extraction driven by a medium-pressure cylinder. Background Technology

[0002] In related technologies, with the increasing proportion of renewable energy, the volatility and intermittency of new energy sources such as wind power and photovoltaics have brought uncertainty to the operation of the power system. As the basic regulation and support unit of the power system, thermal power units face the requirements of more frequent start-ups and shutdowns, greater peak-shaving depth, and faster response speeds. Traditional thermal power peak-shaving methods, such as sliding pressure operation, bypass regulation, and steam extraction heating, although possessing certain regulation capabilities, still have the following main problems: 1. Large boiler thermal inertia and slow regulation response speed, unable to meet the needs of rapid load changes; 2. Poor combustion stability and decreased thermal efficiency under low-load operating conditions, leading to increased coal consumption and emissions; 3. Peak-shaving methods mostly rely on electricity-to-heat conversion, resulting in decreased energy quality and poor system coordination.

[0003] Meanwhile, thermal batteries, as a novel energy storage method, especially medium- and high-temperature thermal storage systems using molten salt as the medium, possess high energy density, long-term thermal storage capacity, and high technological maturity. Deeply coupling thermal batteries with thermal power units to absorb and store excess energy during off-peak hours and release heat energy to assist in heating or power generation during high-load periods is an important direction for improving the unit's regulation range and efficiency. However, most current heat pump-molten salt thermal storage systems use electrically driven high-temperature compressors to heat low-grade heat sources, which has significant drawbacks: 1. Electric drive systems operating at temperatures above 200°C have poor reliability and are expensive, making them difficult to meet engineering application requirements; 2. The electric drive method converts electrical energy into compression work, which increases the electrical load pressure during periods of high grid load, contradicting the original intention of energy storage systems to "smooth out peaks and fill valleys"; 3. There is a lack of deep coordination mechanisms with the main unit system, with energy storage and power generation operating independently, making it difficult to achieve optimal system energy efficiency. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a thermal battery coupled thermal power energy storage system based on steam extraction from a medium-pressure cylinder. This system can directly drive a high-temperature compressor by extracting steam from a steam turbine, replacing the traditional electrically driven compression heat pump. This allows for better energy cascade utilization and significantly reduces the power consumption of the heat pump module.

[0005] According to an embodiment of the present invention, a thermal battery-coupled thermal power energy storage system based on intermediate-pressure cylinder extraction steam drive includes: a thermal power unit module, a heat pump module, an extraction steam drive unit, and a flow regulation and control module. The thermal power unit module includes a boiler, a high-pressure cylinder of a steam turbine, an intermediate-pressure cylinder of a steam turbine, and a low-pressure cylinder of a steam turbine. The main steam outlet of the boiler is connected to the steam inlet of the high-pressure cylinder of the steam turbine; the steam outlet of the high-pressure cylinder of the steam turbine is connected to the reheat steam inlet of the boiler; the reheat steam outlet of the boiler is connected to the steam inlet of the intermediate-pressure cylinder of the steam turbine; and the steam outlet of the intermediate-pressure cylinder of the steam turbine is connected to the steam inlet of the low-pressure cylinder of the steam turbine. The heat pump module circulates a working fluid and includes a high-temperature compressor for compressing the working fluid. The extraction steam drive unit includes an independent steam turbine. The steam inlet of the independent steam turbine is connected to the steam outlet of the intermediate-pressure cylinder of the steam turbine, and the steam outlet of the independent steam turbine is connected to the steam outlet of the low-pressure cylinder of the steam turbine. The output shaft of the independent steam turbine is connected to the high-temperature compressor for driving the high-temperature compressor. The flow regulation control module includes a first regulating valve and a second regulating valve. The first regulating valve is used to control the on / off connection between the steam outlet of the intermediate-pressure cylinder of the steam turbine and the steam inlet of the low-pressure cylinder of the steam turbine, and the second regulating valve is used to control the on / off connection between the steam outlet of the intermediate-pressure cylinder of the steam turbine and the steam inlet of the independent steam turbine.

[0006] According to an embodiment of the present invention, a thermal battery-coupled thermal power energy storage system based on intermediate-pressure cylinder steam extraction drive is provided in the steam extraction drive unit with an independent steam turbine. The steam inlet of the independent steam turbine is connected to the steam outlet of the intermediate-pressure cylinder of the turbine, and the steam outlet of the independent steam turbine is connected to the steam outlet of the low-pressure cylinder of the turbine. The output shaft of the independent steam turbine is connected to a high-temperature compressor to drive the high-temperature compressor of the heat pump module. A flow regulation and control module including a first regulating valve and a second regulating valve is also provided. This allows the high-temperature compressor to be directly driven by steam extraction from the intermediate-pressure cylinder of the turbine, replacing the traditional electrically driven compression heat pump. This enables better energy cascade utilization, improves the heat exchange efficiency of the circulating working fluid in the heat pump module, and significantly reduces the power consumption of the heat pump module. The first and second regulating valves can switch the steam flow direction and achieve dynamic adjustment of the system operating state, enabling flexible adjustment of the output power of the thermal power unit module and deep synergistic coupling between the generator set and the thermal storage system.

[0007] According to some embodiments of the present invention, the high-temperature compressor has an exhaust port and a return port, and the heat pump module further includes a first molten salt heat exchanger and a low-temperature heat exchanger. The first molten salt heat exchanger is provided with a first flow path and a second flow path that exchange heat with each other, and the exhaust port is connected to one end of the first flow path. The low-temperature heat exchanger is provided with a third flow path and a fourth flow path that exchange heat with each other, and the return port is connected to one end of the third flow path. The other end of the first flow path is connected to the other end of the third flow path. The first flow path, the third flow path, and the high-temperature compressor form a loop.

[0008] In some embodiments of the present invention, the heat pump module further includes an expander, in which the circulating working fluid performs work. The expander has an inlet and an outlet. The inlet is connected to the end of the first flow path away from the high-temperature compressor, and the outlet is connected to the end of the third flow path away from the high-temperature compressor.

[0009] In some embodiments of the present invention, the heat pump module further includes a regenerator having a fifth flow path and a sixth flow path that exchange heat with each other. One end of the fifth flow path is connected to the end of the third flow path away from the expander, and the other end of the fifth flow path is connected to the return air port. One end of the sixth flow path is connected to the end of the first flow path away from the high-temperature compressor, and the other end of the sixth flow path is connected to the air inlet. The high-temperature compressor, the first flow path, the sixth flow path, the expander, the third flow path, and the fifth flow path form a loop.

[0010] In some embodiments of the present invention, the thermal power unit module further includes a condenser for condensing steam, the steam inlet of the condenser being connected to the steam outlet of the low-pressure cylinder of the turbine, and the two ends of the fourth flow path being connected to the steam outlet of the independent turbine and the steam inlet of the condenser, respectively.

[0011] In some embodiments of the present invention, the thermal battery coupled thermal power energy storage system based on medium-pressure cylinder extraction steam drive further includes a steam waste heat recovery and cooling module. The steam waste heat recovery and cooling module includes a waste steam cooler. The waste steam cooler has a seventh flow path and an eighth flow path that exchange heat with each other. The two ends of the seventh flow path are respectively connected to the end of the fourth flow path away from the independent steam turbine and the steam inlet of the condenser.

[0012] In some embodiments of the present invention, the thermal battery coupled thermal power energy storage system based on medium-pressure cylinder extraction steam drive further includes a heat storage and heat exchange unit. Molten salt circulates within the heat storage and heat exchange unit. The heat storage and heat exchange unit includes a second molten salt heat exchanger, a first molten salt circulation pump, and a second molten salt circulation pump. The second molten salt heat exchanger is provided with a ninth flow path and a tenth flow path that exchange heat with each other. The second flow path and the ninth flow path form a loop. The tenth flow path is connected in series within the thermal power unit module. The first molten salt circulation pump and the second molten salt circulation pump are used to drive the molten salt circulation flow.

[0013] In some embodiments of the present invention, the heat storage and heat exchange unit further includes a low-temperature molten salt heat storage tank and a high-temperature molten salt heat storage tank. The low-temperature molten salt heat storage tank is connected to one end of the ninth flow path and one end of the second flow path, respectively, for storing molten salt. The first molten salt circulation pump is located between the second molten salt heat exchanger and the low-temperature molten salt heat storage tank. The high-temperature molten salt heat storage tank is connected to the other end of the ninth flow path and the other end of the second flow path, respectively, for storing molten salt. The second molten salt circulation pump is located between the first molten salt heat exchanger and the high-temperature molten salt heat storage tank.

[0014] According to some embodiments of the present invention, the circulating working fluid in the heat pump module is air or argon; and / or, the high-temperature compressor is used to compress and heat the circulating working fluid to a temperature not lower than 500°C.

[0015] According to some embodiments of the present invention, the thermal battery coupled thermal power energy storage system based on medium-pressure cylinder extraction steam drive has a heat storage mode and a heat release mode. In the heat storage mode, the first regulating valve is closed and the second regulating valve is open; in the heat release mode, the first regulating valve is open and the second regulating valve is closed.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0018] Figure 1 This is a schematic diagram of a thermal battery-coupled thermal power energy storage system based on steam extraction from a medium-pressure cylinder, according to an embodiment of the present invention.

[0019] Figure label:

[0020] 1. Boiler; 2. High-pressure cylinder of steam turbine; 3. Intermediate-pressure cylinder of steam turbine; 4. Low-pressure cylinder of steam turbine; 5. Condenser; 6. Condensate pump; 7. Low-pressure heater; 8. Deaerator; 9. Feedwater pump; 10. High-pressure heater; 11. First molten salt heat exchanger; 12. First molten salt circulating pump; 13. Low-temperature molten salt heat storage tank; 14. Second molten salt heat exchanger; 15. Second molten salt circulating pump; 16. High-temperature molten salt heat storage tank; 17. Expander; 18. Low-temperature heat exchanger; 19. Independent steam turbine; 20. High-temperature compressor; 21. Regenerator; 22. Exhaust steam cooler; 23. First regulating valve; 24. Second regulating valve. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] The following is for reference. Figure 1 A thermal battery-coupled thermal power energy storage system based on medium-pressure cylinder extraction steam drive is described according to an embodiment of the present invention.

[0025] According to an embodiment of the present invention, a thermal battery coupled thermal power energy storage system based on medium-pressure cylinder extraction steam drive includes a thermal power unit module, a heat pump module, an extraction steam drive unit, and a flow regulation and control module.

[0026] Specifically, such as Figure 1 As shown, the thermal power unit module includes a boiler 1, a high-pressure turbine cylinder 2, a medium-pressure turbine cylinder 3, and a low-pressure turbine cylinder 4. The main steam outlet of the boiler 1 is connected to the steam inlet of the high-pressure turbine cylinder 2, the steam outlet of the high-pressure turbine cylinder 2 is connected to the reheat steam inlet of the boiler 1, the reheat steam outlet of the boiler 1 is connected to the steam inlet of the medium-pressure turbine cylinder 3, and the steam outlet of the medium-pressure turbine cylinder 3 is connected to the steam inlet of the low-pressure turbine cylinder 4. A circulating working fluid is circulated within the heat pump module, which includes a high-temperature compressor 20 for compressing the circulating working fluid. The extraction steam drive unit includes an independent turbine 19, whose steam inlet is connected to the steam outlet of the medium-pressure turbine cylinder 3, and whose steam outlet is connected to the steam outlet of the low-pressure turbine cylinder 4. The output shaft of the independent turbine 19 is connected to the high-temperature compressor 20 to drive the high-temperature compressor 20. The flow regulation control module includes a first regulating valve 23 and a second regulating valve 24. The first regulating valve 23 is used to control the connection and disconnection between the steam outlet of the intermediate pressure cylinder 3 of the steam turbine and the steam inlet of the low pressure cylinder 4 of the steam turbine. The second regulating valve 24 is used to control the connection and disconnection between the steam outlet of the intermediate pressure cylinder 3 of the steam turbine and the steam inlet of the independent steam turbine 19.

[0027] The thermal battery-coupled thermal power energy storage system driven by intermediate-pressure cylinder steam extraction has both heat storage and heat release modes. The generator in the thermal power unit module is connected to the power grid. When the power grid is operating at low load or when the thermal power unit module is assisted by renewable energy sources such as wind power and photovoltaics with high output efficiency, in order to reduce the power generation load of the thermal power unit module and utilize surplus electrical energy or heat sources, a portion of the high-temperature steam from the steam outlet of the intermediate-pressure cylinder 3 of the turbine is guided into the independent turbine 19 to perform work, provided that the first regulating valve 23 is closed and the second regulating valve 24 is open. The output shaft of the independent turbine 19 is connected to a high-temperature compressor 20, which drives the circulating working fluid in the heat pump module for high-temperature compression. Specifically, the heat pump module can be a Brayton heat pump cycle.

[0028] The heat pump module can specifically adopt a Brayton cycle structure, with air or argon as the working fluid. A high-temperature compressor 20 compresses the working fluid at high temperature, and the output high-temperature gas can release heat in a heat exchanger or similar device to achieve heat storage. After cooling, the gas returns to the high-temperature compressor 20, thus forming a closed loop. The heat pump module effectively stores low-grade heat sources such as waste steam and external heat energy at high temperatures, exhibiting good flexibility and responsiveness.

[0029] When the thermal battery-coupled thermal power energy storage system driven by the extraction of steam from the intermediate-pressure cylinder enters the heat release mode—that is, when the power generation load of the thermal power unit module increases or industrial heating demand arises—the first regulating valve 23 opens and the second regulating valve 24 closes. All the steam from the steam outlet of the intermediate-pressure cylinder 3 of the turbine is introduced into the low-pressure cylinder 4 of the turbine to complete the diffusion work, ensuring that the power generation output of the thermal power unit module is not affected. At the same time, the heat stored in the thermal storage mode can be released to the thermal power unit module through heat exchange, such as through a heat exchanger, to assist the reheat system of boiler 1, industrial heating system, or regional energy system, thereby realizing the reuse of thermal energy storage.

[0030] The independent steam turbine 19 operates only when the first regulating valve 23 is open. The high-temperature compressor 20 it drives does not rely on electric power; instead, it achieves compression work by extracting steam from the intermediate-pressure cylinder 3 of the steam turbine. This steam turbine directly drives the high-temperature compressor 20, replacing the traditional electrically driven compression heat pump. This allows for better energy cascade utilization and significantly reduces the manufacturing difficulty and power consumption of the heat pump module. Utilizing the waste heat from the steam turbine exhaust further improves the heat exchange efficiency of the circulating working fluid in the heat pump module, achieving full utilization of thermal energy in stages.

[0031] Furthermore, the switching mechanism of the first regulating valve 23 and the second regulating valve 24 is simple and reliable, supporting flexible switching between steam extraction and thermal storage or full-condition power generation during actual operation. An interlocking control strategy can be implemented between the first regulating valve 23 and the second regulating valve 24 to switch the steam flow direction and dynamically adjust the system's operating state. This enables mutual exclusion control between steam extraction and the low-pressure cylinder 4 of the turbine, ensuring smooth switching between different operating modes. It can automatically adjust the opening of the first regulating valve 23 and the second regulating valve 24 under changes in grid load, allowing the steam flow direction at the steam outlet of the intermediate-pressure cylinder 3 of the turbine to freely switch between the power generation and steam extraction / thermal storage paths of the low-pressure cylinder 4 of the turbine, and to achieve flexible adjustment of the output power of the thermal power unit module. The system is designed with compact structure, high-temperature resistant working fluid, and flexible operating condition switching as its basic design goals, achieving deep synergistic coupling between the generator set and the thermal storage system.

[0032] This invention is applicable to coal-fired power generating units that require enhanced deep peak-shaving capabilities, storage-type combined heat and power plants, and energy centers in industrial parks that have the need for electric-thermal coupling and coordination. It can be widely used in new power systems that support a high proportion of new energy access.

[0033] According to an embodiment of the present invention, a thermal battery coupled thermal power energy storage system based on intermediate-pressure cylinder steam extraction drive is provided in the steam extraction drive unit with an independent steam turbine 19. The steam inlet of the independent steam turbine 19 is connected to the steam outlet of the intermediate-pressure cylinder 3 of the steam turbine, and the steam outlet of the independent steam turbine 19 is connected to the steam outlet of the low-pressure cylinder 4 of the steam turbine. The output shaft of the independent steam turbine 19 is connected to a high-temperature compressor 20 to drive the high-temperature compressor 20 of the heat pump module. At the same time, a flow regulation and control module including a first regulating valve 23 and a second regulating valve 24 is provided. The high-temperature compressor 20 can be directly driven by steam extraction from the intermediate-pressure cylinder 3 of the steam turbine, replacing the traditional electric-driven compression heat pump form. This can better realize energy cascade utilization, improve the heat exchange efficiency of the circulating working fluid of the heat pump module, and significantly reduce the power consumption of the heat pump module. The first regulating valve 23 and the second regulating valve 24 can switch the steam flow direction and realize the dynamic adjustment of the system operating state, realize the flexible adjustment of the output power of the thermal power unit module, and realize the deep synergistic coupling of the generator set and the thermal storage system.

[0034] In some embodiments of the present invention, such as Figure 1 As shown, the high-temperature compressor 20 has an exhaust port and a return port. The heat pump module also includes a first molten salt heat exchanger 11 and a low-temperature heat exchanger 18. The first molten salt heat exchanger 11 has a first flow path and a second flow path that exchange heat with each other, and the exhaust port is connected to one end of the first flow path. The low-temperature heat exchanger 18 has a third flow path and a fourth flow path that exchange heat with each other, and the return port is connected to one end of the third flow path. The other end of the first flow path is connected to the other end of the third flow path. The first flow path, the third flow path and the high-temperature compressor 20 form a loop.

[0035] The heat pump module employs a Brayton cycle with a single-phase gas as the working fluid, which can be either air or argon. The heat pump module system has a stable structure and strong temperature rise capability, making it suitable for medium- and high-temperature thermal battery heat storage applications. The low-temperature heat exchanger 18 serves both as a waste heat recovery unit for the exhaust steam of the independent steam turbine 19 and as a cold-end heat exchanger for the Brayton cycle, thereby improving the heat absorption efficiency of the heat pump module.

[0036] In the heat pump module cycle, the high-temperature gas output by the high-temperature compressor 20 releases heat and stores heat through the second molten salt heat exchanger 14. After cooling down, it enters the low-temperature heat exchanger 18 to exchange heat with the waste heat of the steam, and then returns to the return port of the high-temperature compressor 20 to form a closed loop.

[0037] The low-temperature heat exchanger 18 is used to absorb low-grade heat energy from the environment or condensate, and the high-temperature compressor 20 is a multi-stage compression structure used to compress and heat the circulating working fluid. In the heat pump module, the circulating working fluid flows through the low-temperature heat exchanger 18 to absorb low-grade heat energy from the environment or condensate, then flows through the high-temperature compressor 20 to be compressed and heated, then flows to the second molten salt heat exchanger 14 to transfer heat to the molten salt, and finally returns to the low-temperature heat exchanger 18 to complete one cycle of the circulating working fluid.

[0038] The heat pump module's operating parameters include compression ratio, working fluid mass flow rate, and cycle regeneration ratio, which are dynamically adjusted based on the external heat source temperature and load demand to achieve stable heat output in the mid-temperature range. This heat pump module effectively stores low-grade heat sources (exhaust steam and external heat energy) at high temperatures, exhibiting good flexibility and responsiveness.

[0039] The low-temperature heat exchanger 18 also has a fourth flow path. The third and fourth flow paths exchange heat with each other. A low-grade heat source flows in the fourth flow path. The high-temperature compressor 20 is used to compress and heat the circulating working fluid to above 250°C. The circulating working fluid in the third flow path exchanges heat with the low-grade heat source in the fourth flow path, and then is further heated by the high-temperature compressor 20. This forms a two-stage heating path with gradual temperature increase, which can improve the utilization rate of low-grade heat and convert low-grade heat energy into high-grade heat energy in stages, ensuring the heat release effect of the heat pump module.

[0040] In some embodiments of the present invention, such as Figure 1 As shown, the heat pump module also includes an expander 17, in which the circulating working fluid performs work. The expander 17 has an inlet and an outlet. The inlet is connected to the end of the first flow path away from the high-temperature compressor 20, and the outlet is connected to the end of the third flow path away from the high-temperature compressor 20. After releasing heat in the second molten salt heat exchanger 14, the circulating working fluid enters the expander 17 to expand and perform work, thus becoming a low-temperature, low-pressure circulating working fluid. After performing work, the circulating working fluid then enters the low-temperature heat exchanger 18, thereby better absorbing low-grade heat energy.

[0041] In some embodiments of the present invention, the heat pump module further includes a regenerator 21, which has a fifth flow path and a sixth flow path that exchange heat with each other. One end of the fifth flow path is connected to the end of the third flow path away from the expander 17, and the other end of the fifth flow path is connected to the return air port. One end of the sixth flow path is connected to the end of the first flow path away from the high-temperature compressor 20, and the other end of the sixth flow path is connected to the air inlet. The high-temperature compressor 20, the first flow path, the sixth flow path, the expander 17, the third flow path, and the fifth flow path form a loop.

[0042] After the circulating working fluid absorbs low-grade heat energy from the environment or condensate in the low-temperature heat exchanger 18, it flows into the regenerator 21 before entering the high-temperature compressor 20. At the same time, after the circulating working fluid transfers heat to the molten salt in the second molten salt heat exchanger 14, it flows into the regenerator 21 before entering the expander 17. This heat exchange can further improve the thermal efficiency of the circulating working fluid.

[0043] In the Brayton cycle of the heat pump module, the circulating working fluid is heated to no less than 250°C by the high-temperature compressor 20, and releases heat in the second molten salt heat exchanger 14 to achieve heat storage. Then, it passes through the regenerator 21, the expander 17 and the low-temperature heat exchanger 18 in sequence to complete energy conversion and closed-loop circulation. The regenerator 21 is used to increase the temperature of the circulating working fluid before compression, thereby improving the heat exchange efficiency of the heat pump module.

[0044] The high-temperature compressor 20 compresses the Brayton cycle working fluid to the required pressure and temperature, with a typical outlet temperature of 250–300°C. The high-temperature gas then enters the second molten salt heat exchanger 14 to exchange heat with the molten salt, transferring the high-temperature heat to the molten salt medium and completing energy storage. The heat-exchanged gas flows into the regenerator 21, where it preheats with the low-temperature working fluid discharged from the expander 17. The working fluid then enters the expander 17 to perform work, releasing expansion energy, completing the isentropic expansion process and reducing its temperature and pressure. The expanded working fluid continues to enter the low-temperature heat exchanger 18, where it exchanges cold-end heat with the medium-temperature exhaust steam discharged from the independent steam turbine 19, further reducing the working fluid temperature. The cooled working fluid flows back to the inlet of the high-temperature compressor 20, forming a complete closed Brayton cycle.

[0045] In some embodiments of the present invention, such as Figure 1 As shown, the thermal power unit module also includes a condenser 5 for condensing steam. The steam inlet of the condenser 5 is connected to the steam outlet of the low-pressure cylinder 4 of the turbine. The two ends of the fourth flow path are connected to the steam outlet of the independent turbine 19 and the steam inlet of the condenser 5, respectively. After the turbine performs its work, the exhaust steam first enters the low-temperature heat exchanger 18 to exchange heat with the cold end of the heat pump module. The cooled steam then enters the condenser 5 to complete condensation. The condensate is sent by the condensate pump 6 to the low-pressure heater 7, deaerator 8, and high-pressure heater 10, and finally returns to the boiler 1 to form a complete steam-water regeneration loop. Before the steam discharged from the independent turbine 19 enters the condenser 5, it exchanges heat with the third flow path in the fourth flow path within the low-temperature heat exchanger 18, which can further improve the heat exchange efficiency of the heat pump module.

[0046] In some embodiments of the present invention, such as Figure 1 As shown, the thermal battery coupled thermal power energy storage system based on the extraction steam from the intermediate pressure cylinder also includes a steam waste heat recovery and cooling module. The steam waste heat recovery and cooling module includes a waste steam cooler 22. The waste steam cooler 22 has a seventh flow path and an eighth flow path that exchange heat with each other. The two ends of the seventh flow path are respectively connected to the end of the fourth flow path away from the independent steam turbine 19 and the steam inlet of the condenser 5.

[0047] After the turbine performs its work, the exhaust steam first enters the low-temperature heat exchanger 18 to exchange heat with the cold end of the heat pump module. Then, it enters the exhaust steam cooler 22 to exchange heat with circulating water for further cooling. Finally, it enters the condenser 5 to complete condensation. The condensate is then pumped by the condensate pump 6 to the low-pressure heater 7, deaerator 8, and high-pressure heater 10, ultimately returning to the boiler 1 to form a complete steam-water regeneration loop. The exhaust steam cooler 22 can further improve the utilization rate of the steam discharged from the independent turbine 19, thereby improving heat exchange efficiency.

[0048] In some embodiments of the present invention, such as Figure 1 As shown, the thermal battery coupled thermal power energy storage system based on medium-pressure cylinder extraction steam drive also includes a heat storage and heat exchange unit. Molten salt circulates in the heat storage and heat exchange unit. The heat storage and heat exchange unit includes a second molten salt heat exchanger 14, a first molten salt circulation pump 12, and a second molten salt circulation pump 15. The second molten salt heat exchanger 14 is provided with a ninth flow path and a tenth flow path that exchange heat with each other. The second flow path and the ninth flow path form a loop. The tenth flow path is connected in series in the thermal power unit module. The first molten salt circulation pump 12 and the second molten salt circulation pump 15 are used to drive the molten salt circulation flow.

[0049] The molten salt stored in the high-temperature molten salt storage tank 16 is transported to the first molten salt heat exchanger 11 by the second molten salt circulation pump 15. It can exchange heat with the working fluid (such as feed water, regenerator 21, etc.) to release heat and be used to assist the reheat system of boiler 1, industrial heating system or regional energy system, so as to realize the reuse of thermal energy.

[0050] When the thermal battery-coupled thermal power energy storage system driven by the extraction of steam from the intermediate-pressure cylinder enters the heat release mode, i.e., when the power generation load of the thermal power unit module increases or industrial heating demand occurs, the first regulating valve 23 opens and the second regulating valve 24 closes. All the steam from the steam outlet of the intermediate-pressure cylinder 3 of the turbine is introduced into the low-pressure cylinder 4 of the turbine to complete the diffusion work, ensuring that the power generation output of the main turbine is not affected. At the same time, the molten salt stored in the high-temperature molten salt heat storage tank 16 is transported to the first molten salt heat exchanger 11 through the second molten salt circulation pump 15. It can exchange heat with the working fluid (such as feedwater, regenerator 21, etc.) to release heat, which is used to assist the reheat system of boiler 1, industrial heating system or regional energy system, realizing the reuse of thermal energy and achieving deep synergistic coupling between the generator set and the thermal storage system.

[0051] In some embodiments of the present invention, such as Figure 1As shown, the heat storage and heat exchange unit also includes a low-temperature molten salt heat storage tank 13 and a high-temperature molten salt heat storage tank 16. The low-temperature molten salt heat storage tank 13 is connected to one end of the ninth flow path and one end of the second flow path, respectively, and is used to store molten salt. The first molten salt circulation pump 12 is located between the second molten salt heat exchanger 14 and the low-temperature molten salt heat storage tank 13. The high-temperature molten salt heat storage tank 16 is connected to the other end of the ninth flow path and the other end of the second flow path, respectively, and is used to store molten salt. The second molten salt circulation pump 15 is located between the first molten salt heat exchanger 11 and the high-temperature molten salt heat storage tank 16.

[0052] The second molten salt heat exchanger 14 is arranged in series with the molten salt electric heater to coordinate the heat output from the heat pump module with the electrically assisted electric heater unit. The molten salt is heated to 300℃-400℃ in the second molten salt heat exchanger 14, and then further heated to 550℃-600℃ by the molten salt electric heater before being stored in the high-temperature molten salt storage tank 16. After releasing heat in the first molten salt heat exchanger 11, the low-temperature molten salt is stored in the low-temperature molten salt storage tank 13, enabling the storage of molten salt heat and facilitating both heat storage and heat release modes, thereby achieving deep synergistic coupling between the generator set and the heat storage system.

[0053] In some embodiments of the present invention, the circulating working fluid within the heat pump module is air or argon, and preferably, the air or argon is in a supercritical state. During the circulation process within the heat pump module, the air or argon remains in a supercritical state, meaning that both its pressure and temperature exceed its critical point. In the supercritical state, the air or argon does not undergo a significant liquid-gas phase transition but exists as a single supercritical fluid. The density, specific heat capacity, and other physical properties of the air or argon change continuously and gradually with temperature or pressure, but there is no two-phase region, resulting in high heat transfer efficiency.

[0054] In some embodiments of the present invention, the high-temperature compressor 20 is used to compress and heat the circulating working fluid to a temperature not lower than 500°C. The high-temperature compressor 20 adopts a multi-stage axial or centrifugal structure, which is suitable for the compression of air or argon under high pressure in the Brayton cycle. The outlet temperature after compression is not lower than 500°C, which can improve the utilization rate of low-grade heat and convert low-grade heat energy into high-grade heat energy in stages, ensuring the heating effect of the heat pump module on the molten salt.

[0055] In some embodiments of the present invention, such as Figure 1 As shown, the thermal battery coupled thermal power energy storage system driven by the extraction of steam from the intermediate pressure cylinder has a heat storage mode and a heat release mode. In the heat storage mode, the first regulating valve 23 is closed and the second regulating valve 24 is open; in the heat release mode, the first regulating valve 23 is open and the second regulating valve 24 is closed.

[0056] The generator in the thermal power unit module is connected to the power grid. When the power grid is operating at a low load or when the thermal power unit module has renewable energy such as wind power and photovoltaic power as auxiliary power and has a high output efficiency, in order to reduce the power generation load of the thermal power unit module and utilize surplus power or heat source, the first regulating valve 23 is opened and the second regulating valve 24 is closed. The steam from the steam outlet of the intermediate pressure cylinder 3 of the steam turbine drives the high temperature compressor 20 through the independent steam turbine 19 to run. After heating the Brayton cycle working fluid, it exchanges heat with the second molten salt heat exchanger 14 to achieve high temperature heat storage. The steam after doing work enters the low temperature heat exchanger 18, the exhaust steam cooler 22 and the condenser 5 in sequence to complete condensation.

[0057] When the thermal battery coupled thermal power energy storage system driven by the extraction of steam from the intermediate-pressure cylinder enters the heat release mode, that is, when the power generation load of the thermal power unit module increases or industrial heating demand occurs, the first regulating valve 23 opens and the second regulating valve 24 closes. The steam from the steam outlet of the intermediate-pressure cylinder 3 of the steam turbine directly enters the low-pressure cylinder 4 of the steam turbine to generate electricity. At the same time, the stored heat energy is released through the first molten salt heat exchanger 11 to assist the reheat system of the boiler 1, the industrial heating system or the regional energy system, etc., to realize the reuse of stored heat energy and to realize the coordinated regulation of system heat and power.

[0058] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0059] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A thermal battery-coupled thermal power energy storage system based on steam extraction driven by a medium-pressure cylinder, characterized in that, include: A thermal power unit module, comprising a boiler, a high-pressure cylinder of a steam turbine, an intermediate-pressure cylinder of a steam turbine, and a low-pressure cylinder of a steam turbine. The main steam outlet of the boiler is connected to the steam inlet of the high-pressure cylinder of the steam turbine, the steam outlet of the high-pressure cylinder of the steam turbine is connected to the reheat steam inlet of the boiler, the reheat steam outlet of the boiler is connected to the steam inlet of the intermediate-pressure cylinder of the steam turbine, and the steam outlet of the intermediate-pressure cylinder of the steam turbine is connected to the steam inlet of the low-pressure cylinder of the steam turbine. A heat pump module, wherein a circulating working fluid is circulated within the heat pump module, and the heat pump module includes a high-temperature compressor for compressing the circulating working fluid; The extraction steam drive unit includes an independent steam turbine. The steam inlet of the independent steam turbine is connected to the steam outlet of the intermediate-pressure cylinder of the steam turbine, and the steam outlet of the independent steam turbine is connected to the steam outlet of the low-pressure cylinder of the steam turbine. The output shaft of the independent steam turbine is connected to the high-temperature compressor for driving the high-temperature compressor. The flow regulation control module includes a first regulating valve and a second regulating valve. The first regulating valve is used to control the connection and disconnection between the steam outlet of the intermediate pressure cylinder of the steam turbine and the steam inlet of the low pressure cylinder of the steam turbine. The second regulating valve is used to control the connection and disconnection between the steam outlet of the intermediate pressure cylinder of the steam turbine and the steam inlet of the independent steam turbine.

2. The thermal battery-coupled thermal power energy storage system based on intermediate-pressure cylinder steam extraction drive according to claim 1, characterized in that, The high-temperature compressor has an exhaust port and an exhaust port, and the heat pump module further includes: The first molten salt heat exchanger is provided with a first flow path and a second flow path that exchange heat with each other, and the exhaust port is connected to one end of the first flow path. The low-temperature heat exchanger has a third flow path and a fourth flow path that exchange heat with each other. The return gas port is connected to one end of the third flow path, and the other end of the first flow path is connected to the other end of the third flow path. The first flow path, the third flow path, and the high-temperature compressor form a loop.

3. The thermal battery-coupled thermal power energy storage system based on medium-pressure cylinder steam extraction drive according to claim 2, characterized in that, The heat pump module also includes: An expander in which a circulating working fluid performs work has an inlet and an outlet. The inlet is connected to the end of the first flow path away from the high-temperature compressor, and the outlet is connected to the end of the third flow path away from the high-temperature compressor.

4. The thermal battery-coupled thermal power energy storage system based on intermediate-pressure cylinder steam extraction drive according to claim 3, characterized in that, The heat pump module also includes: The regenerator has a fifth flow path and a sixth flow path that exchange heat with each other. One end of the fifth flow path is connected to the end of the third flow path away from the expander, and the other end of the fifth flow path is connected to the return gas port. One end of the sixth flow path is connected to the end of the first flow path away from the high-temperature compressor, and the other end of the sixth flow path is connected to the air inlet. The high-temperature compressor, the first flow path, the sixth flow path, the expander, the third flow path, and the fifth flow path form a loop.

5. The thermal battery-coupled thermal power energy storage system based on intermediate-pressure cylinder steam extraction drive according to claim 2, characterized in that, The thermal power unit module also includes a condenser for condensing steam. The steam inlet of the condenser is connected to the steam outlet of the low-pressure cylinder of the turbine. The two ends of the fourth flow path are respectively connected to the steam outlet of the independent turbine and the steam inlet of the condenser.

6. The thermal battery-coupled thermal power energy storage system based on intermediate-pressure cylinder steam extraction drive according to claim 5, characterized in that, The thermal battery-coupled thermal power storage system based on medium-pressure cylinder steam extraction drive also includes a steam waste heat recovery and cooling module, which includes: The exhaust steam cooler has a seventh flow path and an eighth flow path that exchange heat with each other. The two ends of the seventh flow path are respectively connected to the end of the fourth flow path away from the independent steam turbine and the steam inlet of the condenser.

7. The thermal battery-coupled thermal power energy storage system based on intermediate-pressure cylinder steam extraction drive according to claim 2, characterized in that, The thermal battery-coupled thermal power energy storage system based on medium-pressure cylinder steam extraction drive further includes a heat storage and heat exchange unit, which circulates molten salt. The heat storage and heat exchange unit includes: The second molten salt heat exchanger is provided with a ninth flow path and a tenth flow path that exchange heat with each other. The second flow path and the ninth flow path form a loop. The tenth flow path is connected in series in the thermal power unit module. The first molten salt circulation pump and the second molten salt circulation pump are used to drive the molten salt circulation flow.

8. The thermal battery-coupled thermal power energy storage system based on intermediate-pressure cylinder steam extraction drive according to claim 7, characterized in that, The heat storage and heat exchange unit also includes: A low-temperature molten salt heat storage tank is connected to one end of the ninth flow path and one end of the second flow path, respectively, for storing molten salt. The first molten salt circulation pump is located between the second molten salt heat exchanger and the low-temperature molten salt heat storage tank. A high-temperature molten salt heat storage tank is connected to the other end of the ninth flow path and the other end of the second flow path, respectively, for storing molten salt. The second molten salt circulation pump is located between the first molten salt heat exchanger and the high-temperature molten salt heat storage tank.

9. The thermal battery-coupled thermal power energy storage system based on intermediate-pressure cylinder steam extraction drive according to claim 1, characterized in that, The circulating working fluid in the heat pump module is air or argon. And / or, the high-temperature compressor is used to compress and heat the circulating working fluid to a temperature of not less than 500°C.

10. The thermal battery-coupled thermal power energy storage system based on medium-pressure cylinder steam extraction drive according to claim 1, characterized in that, The thermal battery coupled thermal power energy storage system based on medium-pressure cylinder steam extraction drive has a heat storage mode and a heat release mode. In the heat storage mode, the first regulating valve is closed and the second regulating valve is open; in the heat release mode, the first regulating valve is open and the second regulating valve is closed.

Images