Thermal power generating unit coupling type thermal battery energy storage system based on high-temperature heat pump

Abstract

The invention discloses a thermal power generating unit coupling type thermal battery energy storage system based on a high-temperature heat pump. The thermal power generating unit coupling type thermal battery energy storage system based on the high-temperature heat pump comprises a thermal power generating unit steam circulating system, a high-temperature heat pump unit, an electric heater unit and a fused salt heat storage unit. Fused salt circulates in the fused salt heat storage unit, the fused salt heat storage unit comprises a first fused salt heat exchanger and a second fused salt heat exchanger, a first flow path and a second flow path which exchange heat with each other are arranged in the first fused salt heat exchanger, and a third flow path and a fourth flow path which exchange heat with each other are arranged in the second fused salt heat exchanger; the second flow path, the third flow path and the flow path in the electric heater unit form a loop, the first flow path is connected in series in a steam circulating system of the thermal power generating unit, and the fourth flow path is connected in series in the high-temperature heat pump unit. According to the thermal power generating unit coupling type thermal battery energy storage system based on the high-temperature heat pump, a graded heating path of fused salt can be formed, the rapid peak regulation capacity can be achieved, and the energy utilization efficiency can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage and flexibility transformation of thermal power units, and in particular to a thermal power unit-coupled thermal battery energy storage system based on a high-temperature heat pump. Background Art

[0002] In related technologies, as the scale of renewable energy power generation continues to expand, the power system's demand for peak-shaving and frequency-regulating resources continues to grow. As an important regulatory support, thermal power units are faced with the requirements of increasing the load regulation rate, expanding the peak-shaving depth, and improving the flexibility of start-up and shutdown. However, due to the large thermal inertia of the units, the decline in thermal efficiency of deep peak-shaving, and the increased wear and tear of start-up and shutdown, traditional thermal power units have the disadvantages of low operating efficiency and large equipment losses when frequently participating in grid regulation, and are in urgent need of flexibility transformation. Among the current measures to improve the flexibility of thermal power units, thermal energy storage systems are considered to be an effective means to improve the peak-shaving capacity of units because they can store energy during power troughs and release auxiliary power generation during peaks.

[0003] Existing technologies mainly use electric heaters to directly heat the heat storage medium, or use heat pumps to recover low-grade waste heat. However, single electric heating has the problems of low energy efficiency and high cost. Traditional high-temperature heat pumps are limited by the performance limitations of heat pump components, and usually have low output temperatures, which makes it difficult to meet high-temperature energy storage needs.

[0004] In addition, existing energy storage solutions have shortcomings in the utilization of medium and low temperature heat sources, temperature increase in high temperature sections, and deep coupling with the steam system of thermal power units, resulting in low overall system efficiency and insufficient energy storage density, which restricts large-scale application. Summary of the Invention

[0005] The present invention aims to address at least one of the technical problems existing in the prior art. To this end, the present invention proposes a thermal power generation unit-coupled thermal battery energy storage system based on a high-temperature heat pump. This system, coupled with a thermal power generation unit and a thermal battery energy storage system, can form a hierarchical heating path for the molten salt, achieve rapid peak-shaving capabilities, and improve energy efficiency.

[0006] According to an embodiment of the present invention, a thermal power generation unit coupled thermal battery energy storage system based on a high-temperature heat pump comprises: a thermal power generation unit steam cycle system, a high-temperature heat pump unit, an electric heater unit, and a molten salt heat storage unit. The thermal power generation unit steam cycle system comprises a boiler and a steam turbine. A circulating working fluid circulates within the high-temperature heat pump unit. Molten salt circulates within the molten salt heat storage unit. The molten salt heat storage unit comprises a first molten salt heat exchanger and a second molten salt heat exchanger. The first molten salt heat exchanger comprises a first flow path and a second flow path for mutual heat exchange. The second molten salt heat exchanger comprises a third flow path and a fourth flow path for mutual heat exchange. The second and third flow paths form a loop with the flow path within the electric heater unit. In the molten salt circulation flow path, the first molten salt heat exchanger is upstream of the second molten salt heat exchanger, and the second molten salt heat exchanger is upstream of the electric heater unit. The first flow path is connected in series within the thermal power generation unit steam cycle system, and the fourth flow path is connected in series within the high-temperature heat pump unit. The molten salt heat storage unit further comprises a drive pump for driving the circulation of the molten salt.

[0007] According to an embodiment of the present invention, a thermal power unit-coupled thermal battery energy storage system based on a high-temperature heat pump is provided within a molten salt heat storage unit. In the molten salt circulation path, the first molten salt heat exchanger is positioned upstream of the second molten salt heat exchanger, and the second molten salt heat exchanger is positioned upstream of the electric heater unit. This creates a series heating structure in which the high-temperature heat pump unit and the electric heater unit are connected. The medium and low temperature heat sections are heated by the high-temperature heat pump unit, while the high temperature heat section is heated by the electric heater unit. This creates a two-stage, gradually increasing temperature molten salt heating path, gradually converting low-grade thermal energy into high-quality thermal energy, thereby reducing energy consumption and costs. Furthermore, the molten salt heat storage system is efficiently coupled with the steam circulation system of the thermal power unit to heat boiler feed water and / or reheated steam for the steam turbine, thereby improving steam parameters or achieving rapid load increase. This significantly enhances the unit's rapid peak-shaving capability and energy efficiency.

[0008] According to some embodiments of the present invention, the high-temperature heat pump unit includes a high-temperature compressor and a low-temperature heat exchanger, the high-temperature compressor is used to compress the circulating working fluid, the high-temperature compressor has an exhaust port and a return air port, the exhaust port is connected to one end of the fourth flow path; the low-temperature heat exchanger has a fifth flow path, and the two ends of the fifth flow path are respectively connected to the other end of the fourth flow path and the return air port.

[0009] In some embodiments of the present invention, the low-temperature heat exchanger further has a sixth flow path, the fifth flow path and the sixth flow path exchange heat with each other, a low-grade heat source flows in the sixth flow path, the temperature of the low-grade heat source is 50°C-150°C, and the high-temperature compressor is used to compress the circulating working fluid and raise the temperature to 300°C-400°C.

[0010] In some embodiments of the present invention, the high-temperature heat pump unit also includes an expander, in which the circulating working medium performs work, and the expander has an air inlet and an air outlet, the air inlet is connected to the end of the fourth flow path away from the high-temperature compressor, and the air outlet is connected to the end of the fifth flow path away from the high-temperature compressor.

[0011] In some embodiments of the present invention, the high-temperature heat pump unit also includes a regenerator, which has a seventh flow path and an eighth flow path for mutual heat exchange, one end of the seventh flow path is connected to the end of the fifth flow path facing away from the expander, the other end of the seventh flow path is connected to the return air port, one end of the eighth flow path is connected to the end of the fourth flow path facing away from the high-temperature compressor, and the other end of the eighth flow path is connected to the air inlet.

[0012] According to some embodiments of the present invention, the circulating working medium in the high-temperature heat pump unit is air or argon and is in a supercritical state.

[0013] According to some embodiments of the present invention, the electric heater unit includes a molten salt electric heater for electrically heating the molten salt in the molten salt heat storage unit.

[0014] According to some embodiments of the present invention, the molten salt heat storage 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 being respectively connected to one end of the second flow path and one end of the third flow path, for storing molten salt, and the first molten salt circulation pump being arranged between the first molten salt heat exchanger and the low-temperature molten salt heat storage tank; the high-temperature molten salt heat storage tank being respectively connected to the other end of the second flow path and the other end of the third flow path, for storing molten salt, and the second molten salt circulation pump being arranged between the electric heater unit and the high-temperature molten salt heat storage tank.

[0015] According to some embodiments of the present invention, the molten salt is heated to 300°C-400°C by the high temperature heat pump unit, and the molten salt is heated to 550°C-600°C by the electric heater unit.

[0016] According to some embodiments of the present invention, the thermal power unit coupled thermal battery energy storage system based on a high-temperature heat pump has a charging mode and a heat release mode. In the charging mode, the first flow path is disconnected, the fourth flow path is flowing, and the high-temperature heat pump unit and the electric heater unit heat the molten salt in turn; in the heat release mode, the first flow path is flowing, the fourth flow path is disconnected, and the molten salt releases heat to the steam circulation system of the thermal power unit.

[0017] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which: Figure 1 Schematic diagram of the structure of a thermal power generation unit coupled thermal battery energy storage system based on a high-temperature heat pump according to an embodiment of the present invention.

[0019] Reference numerals: 100. Thermal battery energy storage system coupled with thermal power generation unit based on high-temperature heat pump; 1. Boiler; 2. High-pressure cylinder; 3. Medium-pressure cylinder; 4. Low-pressure cylinder; 5. Condenser; 6. Condensate pump; 7. Low-pressure heater; 8. Deaerator; 9. Feedwater pump; 10. High-pressure heater; 11. First molten salt heat exchanger; 111. First flow path; 112. Second flow path; 120. Drive pump; 12. First molten salt circulation pump; 13. Low-temperature molten salt heat storage tank; 14. Second molten salt heat exchanger; 141. Third flow path 142, fourth flow path; 15, molten salt electric heater; 16, second molten salt circulation pump; 17, high-temperature molten salt heat storage tank; 18, expander; 181, air inlet; 182, air outlet; 19, low-temperature heat exchanger; 191, fifth flow path; 192, sixth flow path; 20, high-temperature compressor; 201, exhaust port; 202, return air port; 21, regenerator; 211, seventh flow path; 212, eighth flow path. DETAILED DESCRIPTION

[0020] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0021] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0022] Reference below Figure 1 A thermal power generation unit coupled thermal battery energy storage system 100 based on a high temperature heat pump according to an embodiment of the present invention is described.

[0023] The thermal power generation unit coupled thermal battery energy storage system 100 based on a high-temperature heat pump according to an embodiment of the present invention includes a thermal power generation unit steam cycle system, a high-temperature heat pump unit, an electric heater unit and a molten salt heat storage unit.

[0024] Specifically, such as Figure 1 As shown, the steam circulation system of the thermal power unit includes a boiler 1 and a steam turbine, a circulating working medium circulates in the high-temperature heat pump unit, and a molten salt circulates in the molten salt heat storage unit. The molten salt heat storage unit includes a first molten salt heat exchanger 11 and a second molten salt heat exchanger 14. The first molten salt heat exchanger 11 is provided with a first flow path 111 and a second flow path 112 for mutual heat exchange, and the second molten salt heat exchanger 14 is provided with a third flow path 141 and a fourth flow path 142 for mutual heat exchange. The second flow path 112, the third flow path 141 and the flow path in the electric heater unit form a loop. In the circulation flow path of the molten salt, the first molten salt heat exchanger 11 is upstream of the second molten salt heat exchanger 14, and the second molten salt heat exchanger 14 is upstream of the electric heater unit. The first flow path 111 is connected in series in the steam circulation system of the thermal power unit, and the fourth flow path 142 is connected in series in the high-temperature heat pump unit. The molten salt heat storage unit also includes a driving pump 120 for driving the circulation of the molten salt.

[0025] The molten salt thermal storage unit is used to store heat generated by the high-temperature heat pump unit and to heat the feed water for boiler 1 and / or the reheated steam for the steam turbine. This means that the high-temperature heat pump-based thermal power unit-coupled thermal battery energy storage system 100 can operate in both charging and discharging modes.

[0026] In charging mode, the electric heater unit is positioned downstream of the second molten salt heat exchanger 14 as the molten salt circulates within the molten salt heat storage unit. After absorbing intermediate-temperature heat from the high-temperature heat pump unit at the second molten salt heat exchanger 14, the molten salt enters the electric heater unit for further heating. The electric heater unit can heat the molten salt using either resistive or inductive electric heating, further raising its temperature to generate high-quality thermal energy.

[0027] In heat release mode, the high-temperature molten salt is deeply coupled with the thermal power unit's steam cycle through the first molten salt heat exchanger 11. The first molten salt heat exchanger 11 can be deployed upstream of the boiler 1 economizer, in the boiler 1 feedwater line, or in the reheat section between the intermediate-pressure and high-pressure cylinders 3 and 2 of the steam turbine. It is used to increase the boiler 1 feedwater temperature and / or the reheat steam parameters of the turbine's intermediate-pressure cylinder 3, thereby enhancing the steam quality and output power of the thermal power unit's steam cycle. By adjusting the molten salt flow rate and the opening of the first molten salt heat exchanger 11, flexible control functions such as rapid peak shaving and assisted start-stop can be achieved.

[0028] The first molten salt heat exchanger 11 is used to release the heat of the high-temperature molten salt to the boiler 1 water feed pipeline, economizer inlet or medium-pressure cylinder 3 reheater inlet section of the steam circulation system of the thermal power unit through heat exchange in the heat release mode to improve steam parameters.

[0029] The thermal power generation unit coupled thermal battery energy storage system 100 based on a high-temperature heat pump can operate only in the heat charging mode or only in the heat dissipation mode, can operate in both the heat charging mode and the heat dissipation mode simultaneously, or can stop operating in both the heat charging mode and the heat dissipation mode, that is, maintain a standby state.

[0030] In the molten salt heat storage unit, the driving pump 120 includes a first molten salt circulation pump 12 and a second molten salt circulation pump 16. The low-temperature molten salt flows through the second molten salt heat exchanger 14 to absorb heat. The molten salt after the temperature is increased is driven by the second molten salt circulation pump 16, is further heated in the electric heater unit, and then flows to the first molten salt heat exchanger 11. The high-temperature molten salt heats the boiler 1 feed water or the reheated steam of the steam turbine into high-temperature and high-pressure steam in the first molten salt heat exchanger 11, thereby increasing the output power of the steam circulation system of the thermal power unit, and then flows to the second molten salt heat exchanger 14 driven by the second molten salt circulation pump 16 to absorb heat, thereby completing a cycle.

[0031] The entire system's operation is centrally coordinated by the energy control system. Based on real-time information such as the molten salt level, temperature, high-temperature heat pump unit operating parameters, electric heater unit operating power, electricity prices, and load forecasts, it intelligently switches between charging, discharging, and standby states. It also dynamically adjusts the high-temperature heat pump unit load, electric heater unit power, and molten salt flow rate, ensuring high stability and responsiveness across all operating phases of the high-temperature heat pump-based thermal power generation unit-coupled thermal battery energy storage system 100. The high-temperature heat pump-based thermal power generation unit-coupled thermal battery energy storage system 100 has significant engineering applicability, particularly suitable for enhancing the flexibility of coal-fired power generation units in new power systems, or for promotion and application in scenarios such as curtailment and peak-shaving energy storage.

[0032] By synergizing heating between the high-temperature heat pump unit and the electric heater unit, and combining their respective applicable temperature ranges, they achieve segmented heat utilization and heating, improving overall heat exchange efficiency and system control flexibility. This also reduces the load on the high-temperature heat pump unit and optimizes equipment configuration. The high-temperature heat pump unit, which only provides heat in the medium-temperature range, significantly reduces its design pressure, temperature, and compression ratio. This facilitates the use of more versatile materials and structures, reduces the volume of the high-temperature heat pump unit, and improves system manufacturability. In conjunction with the electric heater unit, the molten salt heating temperature can be effectively increased to meet high-temperature energy storage requirements. Furthermore, this design enhances system flexibility and adaptability, providing a clearer system architecture. The high-temperature heat pump unit, electric heater unit, and molten salt heat storage unit are modularly arranged, adaptable to various low-temperature heat source connections and suitable for both new and retrofitted thermal power unit steam cycle systems. The molten salt heat storage unit enables high-temperature molten salt heat storage and efficient peak-shaving output. With its high energy density and excellent heat storage and release stability, it can achieve deep peak shaving and dynamic response when combined with the thermal power unit steam cycle system.

[0033] The high-temperature heat pump-based thermal power unit-coupled thermal battery energy storage system 100 utilizes a series heating structure with a high-temperature heat pump unit and an electric heater unit. The medium and low-temperature heat sections are heated by the high-temperature heat pump unit, while the high-temperature heat section is heated by the electric heater unit. This creates a two-stage, gradually increasing molten salt heating path, converting low-grade thermal energy into high-quality energy in a graded manner, thereby reducing energy consumption and costs. Furthermore, the molten salt heat storage system is efficiently coupled with the thermal power unit's steam cycle system to improve steam parameters or achieve rapid load increases, significantly enhancing the unit's rapid peak-shaving capability and energy efficiency.

[0034] In summary, the present invention constructs a hierarchical heating path by connecting a high-temperature heat pump unit and an electric heater unit in series to form a composite high-temperature heat pump-based thermal power unit-coupled thermal battery energy storage system 100 with a clear structure, balanced efficiency, and wide applicability. The system has broad application prospects in scenarios such as coal-fired power flexibility transformation, heat storage peak regulation, and grid support.

[0035] According to an embodiment of the present invention, a thermal power unit coupled thermal battery energy storage system 100 based on a high-temperature heat pump is provided within a molten salt heat storage unit. In the molten salt circulation path, the first molten salt heat exchanger 11 is positioned upstream of the second molten salt heat exchanger 14, and the second molten salt heat exchanger 14 is positioned upstream of the electric heater unit. This allows for a series heating structure of a high-temperature heat pump unit and an electric heater unit. The medium and low temperature heat sections are heated by the high-temperature heat pump unit, while the high temperature heat section is heated by the electric heater unit. This constitutes a two-stage, gradually increasing temperature molten salt heating path, gradually converting low-grade thermal energy into high-quality thermal energy in a graded manner, thereby reducing energy consumption and costs. At the same time, the molten salt heat storage system is efficiently coupled with the steam circulation system of the thermal power unit to heat the feed water of the boiler 1 and / or the reheated steam of the steam turbine, thereby improving steam parameters or achieving rapid load increase. This significantly improves the unit's rapid peak-shaving capability and energy utilization efficiency.

[0036] In some embodiments, as Figure 1 As shown, the steam cycle system of a thermal power unit includes a boiler 1, a high-pressure cylinder 2, an intermediate-pressure cylinder 3, a low-pressure cylinder 4 of a steam turbine, a condenser 5, a condensate pump 6, a low-pressure heater 7, a deaerator 8, a feedwater pump 9, and a high-pressure heater 10. In the steam cycle system of a thermal power unit, feedwater from boiler 1 enters boiler 1 for heating and generates main steam. The main steam enters the high-pressure cylinder 2 of the steam turbine through a steam pipeline to perform work. After performing work, the exhaust steam returns to boiler 1 through a reheat pipeline for heating. The generated reheated steam enters the intermediate-pressure cylinder 3 to perform work. The exhaust steam from the intermediate-pressure cylinder 3 continues to enter the low-pressure cylinder 4 to perform work. The exhaust steam from the low-pressure cylinder 4 after performing work enters the condenser 5 for condensation. The condensed condensate is then transported by the condensate pump 6 to the low-pressure heater 7 for heating. After heating, it is transported to the deaerator 8 for deoxygenation. After passing through the feedwater pump 9 and the high-pressure heater 10, it enters the boiler 1, completing a steam-water cycle.

[0037] In some embodiments of the present invention, Figure 1 As shown, the high-temperature heat pump unit includes a high-temperature compressor 20 and a low-temperature heat exchanger 19. The high-temperature compressor 20 is used to compress the circulating working medium. The high-temperature compressor 20 has an exhaust port 201 and a return air port 202. The exhaust port 201 is connected to one end of the fourth flow path 142; the low-temperature heat exchanger 19 has a fifth flow path 191, and the two ends of the fifth flow path 191 are respectively connected to the other end of the fourth flow path 142 and the return air port 202.

[0038] Low-temperature heat exchanger 19 absorbs low-grade heat energy from the environment or condensate. High-temperature compressor 20 uses a multi-stage compression structure to compress and heat the circulating working fluid. In the high-temperature heat pump unit, the circulating working fluid flows through low-temperature heat exchanger 19, absorbing low-grade heat energy from the environment or condensate. It then flows through high-temperature compressor 20 for compression and temperature increase. It then flows to the second molten salt heat exchanger 14, transferring heat to the molten salt, before returning to low-temperature heat exchanger 19, completing a single cycle of the circulating working fluid.

[0039] The operating parameters of the high-temperature heat pump unit include compression ratio, working fluid mass flow rate and circulation heat recovery ratio, which are dynamically adjusted according to the external heat source temperature and load demand to achieve stable heat output in the medium temperature range.

[0040] In some embodiments of the present invention, Figure 1 As shown, the low-temperature heat exchanger 19 further includes a sixth flow path 192. The fifth flow path 191 and the sixth flow path 192 exchange heat with each other. A low-grade heat source flows in the sixth flow path 192. The temperature of the low-grade heat source is 50°C-150°C. The high-temperature compressor 20 is used to compress the circulating working fluid and raise its temperature to 300°C-400°C. The circulating working fluid in the fifth flow path 191 exchanges heat with the low-grade heat source in the sixth flow path 192, and is then compressed by the high-temperature compressor 20 to further increase its temperature. This forms a two-stage, gradually increasing heating path, which can improve the utilization rate of the low-grade heat and convert the low-grade thermal energy into high-quality thermal energy in a graded manner, ensuring the heating effect of the high-temperature heat pump unit on the molten salt.

[0041] In some embodiments of the present invention, Figure 1 As shown, the high-temperature heat pump unit also includes an expander 18, in which the circulating working fluid performs work. The expander 18 has an air inlet 181 and an air outlet 182. The air inlet 181 is connected to the end of the fourth flow path 142 that faces away from the high-temperature compressor 20, and the air outlet 182 is connected to the end of the fifth flow path 191 that faces 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 18 to expand and perform work, thereby becoming a low-temperature, low-pressure circulating working fluid. After performing work, the circulating working fluid then enters the low-temperature heat exchanger 19, thereby better absorbing low-grade thermal energy.

[0042] In some embodiments of the present invention, Figure 1As shown, the high-temperature heat pump unit further includes a regenerator 21, which includes a seventh flow path 211 and an eighth flow path 212 for heat exchange with each other. One end of the seventh flow path 211 is connected to the end of the fifth flow path 191 facing away from the expander 18, and the other end of the seventh flow path 211 is connected to the return air port 202. One end of the eighth flow path 212 is connected to the end of the fourth flow path 142 facing away from the high-temperature compressor 20, and the other end of the eighth flow path 212 is connected to the air inlet 181. After absorbing low-grade heat energy from the environment or condensate in the low-temperature heat exchanger 19, the circulating fluid first flows into the seventh flow path 211 of the regenerator 21 before entering the high-temperature compressor 20. Simultaneously, after transferring heat to the molten salt in the second molten salt heat exchanger 14, the circulating fluid first flows into the eighth flow path 212 of the regenerator 21 before entering the expander 18. This heat exchange further improves the thermal efficiency of the circulating fluid.

[0043] In some embodiments of the present invention, Figure 1 As shown, the circulating working fluid within the high-temperature heat pump unit is air or argon in a supercritical state. During its circulation within the high-temperature heat pump unit, the air or argon remains in a supercritical state. This means that both its pressure and temperature exceed its critical point. In this supercritical state, the air or argon undergoes no distinct liquid-to-gas phase transition, existing instead as a single supercritical fluid. Physical properties such as density and specific heat capacity vary continuously with temperature or pressure, but there is no two-phase region, resulting in high heat transfer efficiency.

[0044] In some embodiments of the present invention, Figure 1 As shown, the electric heater unit includes a molten salt electric heater 15 for electrically heating the molten salt in the molten salt heat storage unit.

[0045] The molten salt electric heater 15 is connected to the outlet of the third flow path 141 of the second molten salt heat exchanger 14, and is used to further heat the molten salt heated by the high-temperature heat pump unit, thereby forming high-temperature molten salt, which facilitates the subsequent flow of the molten salt through the first molten salt heat exchanger 11 to exchange heat with the steam circulation system of the thermal power unit.

[0046] The operation of the molten salt electric heater 15 is dynamically controlled by the energy management system according to parameters such as electricity price, molten salt temperature, heat storage rate, etc., to achieve coordinated operation with the high-temperature heat pump unit.

[0047] It should be noted that a temperature and flow regulating device is provided between the second molten salt heat exchanger 14 and the molten salt electric heater 15, which is used to dynamically control the output power of the molten salt electric heater 15 and the difference in molten salt entering and leaving the molten salt electric heater 15, so as to achieve segmented precise thermal control.

[0048] In some embodiments of the present invention, Figure 1As shown, the molten salt heat storage unit further includes a low-temperature molten salt heat storage tank 13 and a high-temperature molten salt heat storage tank 17. The low-temperature molten salt heat storage tank 13 is respectively connected to one end of the second flow path 112 and one end of the third flow path 141, and is used to store molten salt. The first molten salt circulation pump 12 is arranged between the first molten salt heat exchanger 11 and the low-temperature molten salt heat storage tank 13; the high-temperature molten salt heat storage tank 17 is respectively connected to the other end of the second flow path 112 and the other end of the third flow path 141, and is used to store molten salt. The second molten salt circulation pump 16 is arranged between the electric heater unit and the high-temperature molten salt heat storage tank 17.

[0049] The second molten salt heat exchanger 14 is arranged in series with the molten salt electric heater 15, synergizing the heat output from the high-temperature heat pump unit with the power-assisted electric heater unit. The molten salt is heated to 300°C-400°C in the second molten salt heat exchanger 14, then heated to 550°C-600°C by the molten salt electric heater 15 before being stored in the high-temperature molten salt heat storage tank 17. After releasing heat in the first molten salt heat exchanger 11, the lower-temperature molten salt is stored in the low-temperature molten salt heat storage tank 13.

[0050] The molten salt heat storage unit adopts a double-tank structure. The low-temperature molten salt heat storage tank 13 and the high-temperature molten salt heat storage tank 17 correspond to the temperature ranges of 280℃-320℃ and 550℃-600℃ respectively. The first molten salt circulation pump 12 and the second molten salt circulation pump 16 are used for medium-temperature heating cycle and high-temperature heat release cycle respectively.

[0051] In some embodiments of the present invention, Figure 1 As shown, the molten salt is heated to 300°C-400°C by the high-temperature heat pump unit, and then to 550°C-600°C by the electric heater unit. The high-temperature heat pump unit only provides heat in the medium-temperature range, resulting in significantly lower design pressure, temperature, and compression ratio. This facilitates the use of more versatile materials and structures, reduces the volume of the high-temperature heat pump unit, and improves system manufacturability. The electric heater unit heats the molten salt to a high temperature, facilitating efficient coupling between the molten salt heat storage system and the steam cycle of the thermal power unit. This allows for increased steam parameters or rapid load increases, significantly enhancing the unit's rapid peak-shaving capability and energy efficiency.

[0052] In some embodiments of the present invention, Figure 1 As shown, the thermal power generation unit coupled thermal battery energy storage system 100 based on a high-temperature heat pump has a charging mode and a heat release mode. In the charging mode, the first flow path 111 is disconnected, the fourth flow path 142 is flowing, and the high-temperature heat pump unit and the electric heater unit heat the molten salt in turn; in the heat release mode, the first flow path 111 is flowing, the fourth flow path 142 is disconnected, and the molten salt releases heat to the steam circulation system of the thermal power generation unit.

[0053] In charging mode, the electric heater unit is positioned downstream of the second molten salt heat exchanger 14 as the molten salt circulates within the molten salt heat storage unit. After absorbing intermediate-temperature heat from the high-temperature heat pump unit at the second molten salt heat exchanger 14, the molten salt enters the electric heater unit for further heating. The electric heater unit can heat the molten salt using either resistive or inductive electric heating, further raising its temperature to generate high-quality thermal energy.

[0054] In heat release mode, the high-temperature molten salt is deeply coupled with the thermal power unit's steam cycle through the first molten salt heat exchanger 11. The first molten salt heat exchanger 11 can be deployed upstream of the boiler 1 economizer, in the boiler 1 feedwater line, or in the reheat section between the intermediate-pressure and high-pressure cylinders 3 and 2 of the steam turbine. It is used to increase the boiler 1 feedwater temperature and / or the reheat steam parameters of the turbine's intermediate-pressure cylinder 3, thereby enhancing the steam quality and output power of the thermal power unit's steam cycle. By adjusting the molten salt flow rate and the opening of the first molten salt heat exchanger 11, flexible control functions such as rapid peak shaving and assisted start-stop can be achieved.

[0055] The first molten salt heat exchanger 11 is used to release the heat of the high-temperature molten salt to the boiler 1 water feed pipeline, economizer inlet or medium-pressure cylinder 3 reheater inlet section of the steam circulation system of the thermal power unit through heat exchange in the heat release mode to improve steam parameters.

[0056] The thermal power generation unit coupled thermal battery energy storage system 100 based on a high-temperature heat pump can operate only in the heat charging mode or only in the heat dissipation mode, can operate in both the heat charging mode and the heat dissipation mode simultaneously, or can stop operating in both the heat charging mode and the heat dissipation mode, that is, maintain a standby state.

[0057] A specific embodiment of the operation steps of the thermal power generation unit coupled thermal battery energy storage system 100 based on a high-temperature heat pump is described below.

[0058] After the high-temperature heat pump unit is activated, the supercritical air or argon working fluid absorbs ambient or condensate heat in the low-temperature heat exchanger 19. After being heated, it enters the regenerator 21 for preheating. It is then compressed by the high-temperature compressor 20 to raise its temperature to 300°C-400°C. The high-temperature circulating working fluid enters the second molten salt heat exchanger 14, transfers heat to the molten salt, and after performing work in the expander 18, returns to the low-temperature heat exchanger 19, completing the cycle. After being heated to a medium temperature, the molten salt is heated to 550°C-600°C by an electric heater and stored in the high-temperature molten salt heat storage tank 17.

[0059] In heat release mode, the high-temperature molten salt is deeply coupled with the steam cycle system of the thermal power unit through the first molten salt heat exchanger 11. The first molten salt heat exchanger 11 can be deployed in the upstream section of the boiler 1 economizer, the boiler 1 feedwater pipeline, or the reheat section between the intermediate-pressure cylinder 3 and the high-pressure cylinder 2 of the steam turbine. It is used to increase the boiler 1 feedwater temperature and / or the reheat steam parameters of the intermediate-pressure cylinder 3 of the steam turbine, thereby enhancing the steam quality and output power of the thermal power unit's steam cycle system. After heat release, the low-temperature molten salt is stored in the low-temperature molten salt heat storage tank 13, ready to flow to the second molten salt heat exchanger 14 in the charging mode to complete the circulation.

[0060] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses 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 any one or more embodiments or examples.

[0061] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A thermal power generation unit coupled thermal battery energy storage system based on a high-temperature heat pump, characterized in that: include: A steam cycle system of a thermal power unit, comprising a boiler and a steam turbine; A high-temperature heat pump unit and an electric heater unit, wherein a circulating working medium circulates in the high-temperature heat pump unit; A molten salt heat storage unit, in which molten salt circulates, and the molten salt heat storage unit includes a first molten salt heat exchanger and a second molten salt heat exchanger, wherein a first flow path and a second flow path for mutual heat exchange are provided in the first molten salt heat exchanger, and a third flow path and a fourth flow path for mutual heat exchange are provided in the second molten salt heat exchanger, and the second flow path, the third flow path, and the flow path in the electric heater unit form a loop. In the circulation flow path of the molten salt, the first molten salt heat exchanger is upstream of the second molten salt heat exchanger, and the second molten salt heat exchanger is upstream of the electric heater unit. The first flow path is connected in series in the steam circulation system of the thermal power unit, and the fourth flow path is connected in series in the high-temperature heat pump unit. The molten salt heat storage unit also includes a driving pump for driving the circulation of the molten salt.

2. The thermal power generation unit coupled thermal battery energy storage system based on a high-temperature heat pump according to claim 1 is characterized in that: The high temperature heat pump unit comprises: a high-temperature compressor, the high-temperature compressor being used to compress a circulating working medium, the high-temperature compressor having an exhaust port and an air return port, the exhaust port being connected to one end of the fourth flow path; The low-temperature heat exchanger has a fifth flow path therein, and both ends of the fifth flow path are respectively connected to the other end of the fourth flow path and the return air port.

3. The thermal power generation unit coupled thermal battery energy storage system based on a high-temperature heat pump according to claim 2 is characterized in that: The low-temperature heat exchanger also has a sixth flow path, and the fifth flow path and the sixth flow path exchange heat with each other. A low-grade heat source flows in the sixth flow path, and the temperature of the low-grade heat source is 50°C-150°C. The high-temperature compressor is used to compress the circulating working fluid and raise the temperature to 300°C-400°C.

4. The thermal power generation unit coupled thermal battery energy storage system based on a high-temperature heat pump according to claim 2, characterized in that: The high temperature heat pump unit further comprises: An expander in which the circulating working medium performs work, the expander having an air inlet and an air outlet, the air inlet being connected to an end of the fourth flow path away from the high-temperature compressor, and the air outlet being connected to an end of the fifth flow path away from the high-temperature compressor.

5. The thermal power generation unit coupled thermal battery energy storage system based on a high temperature heat pump according to claim 4 is characterized in that: The high temperature heat pump unit further comprises: A regenerator, wherein the regenerator has a seventh flow path and an eighth flow path for mutual heat exchange, one end of the seventh flow path is connected to the end of the fifth flow path facing away from the expander, the other end of the seventh flow path is connected to the return air port, one end of the eighth flow path is connected to the end of the fourth flow path facing away from the high-temperature compressor, and the other end of the eighth flow path is connected to the air inlet.

6. The thermal power generation unit coupled thermal battery energy storage system based on a high temperature heat pump according to claim 1, characterized in that: The circulating working medium in the high-temperature heat pump unit is air or argon and is in a supercritical state.

7. The thermal power generation unit coupled thermal battery energy storage system based on a high temperature heat pump according to claim 1, characterized in that: The electric heater unit comprises: The molten salt electric heater is used to electrically heat the molten salt in the molten salt heat storage unit.

8. The thermal power generation unit coupled thermal battery energy storage system based on a high temperature heat pump according to claim 1, characterized in that: The molten salt heat storage unit further includes: a low-temperature molten salt heat storage tank, the low-temperature molten salt heat storage tank being connected to one end of the second flow path and one end of the third flow path respectively, and being used to store molten salt; the first molten salt circulation pump being provided between the first 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 second flow path and the other end of the third flow path respectively, and is used to store molten salt. The second molten salt circulation pump is provided between the electric heater unit and the high-temperature molten salt heat storage tank.

9. The thermal power generation unit coupled thermal battery energy storage system based on a high temperature heat pump according to claim 1, characterized in that: The molten salt is heated to 300°C-400°C by the high-temperature heat pump unit, and the molten salt is heated to 550°C-600°C by the electric heater unit.

10. The thermal power generation unit coupled thermal battery energy storage system based on a high temperature heat pump according to claim 1, characterized in that: The thermal power unit-coupled thermal battery energy storage system based on a high-temperature heat pump has a charging mode and a heat release mode. In the charging mode, the first flow path is disconnected, the fourth flow path is flowing, and the high-temperature heat pump unit and the electric heater unit heat the molten salt in turn; in the heat release mode, the first flow path is flowing, the fourth flow path is disconnected, and the molten salt releases heat to the steam circulation system of the thermal power unit.

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