A supercritical carbon dioxide cycle coupled thermal power generation system

Abstract

This invention provides a thermal power generation system coupled with a supercritical carbon dioxide cycle, comprising: a thermal power unit, which includes a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a low-pressure feedwater heater group, a deaerator, and a high-pressure feedwater heater group connected in sequence to form a steam circulation loop; the extraction steam output end of the low-pressure cylinder is connected to the low-pressure feedwater heater group, and the extraction steam output ends of the intermediate-pressure cylinder and the high-pressure cylinder are respectively connected to the high-pressure feedwater heater group; a supercritical carbon dioxide subsystem, which includes a low-pressure cooler group, a first compressor, a high-pressure heater group, and a first turbine connected in series to form a working fluid circulation loop; the feedwater of the low-pressure feedwater heater group flows through the cold side of the low-pressure cooler group; the extraction steam output end of the intermediate-pressure cylinder, the hot side of the high-pressure heater group, and the hot side of the high-pressure feedwater heater group are connected in sequence, and / or, the extraction steam output end of the high-pressure cylinder, the hot side of the high-pressure heater group, and the hot side of the high-pressure feedwater heater group are connected in sequence.

Description

Technical Field

[0001] This invention belongs to the field of power generation system technology, specifically relating to a thermal power generation system coupled with a supercritical carbon dioxide cycle. Background Technology

[0002] my country's energy structure is rapidly transitioning towards a clean and low-carbon model, with renewable energy generation continuing its vigorous development and the installed capacity of new energy sources such as wind power and photovoltaics constantly increasing. However, renewable energy is characterized by intermittency, volatility, and uncontrollability, posing challenges to the safe and stable operation of the power grid after large-scale grid connection. This is particularly true in areas with a high proportion of renewable energy connected to the grid, where problems such as wind and solar curtailment and grid frequency fluctuations frequently occur. Therefore, it is necessary to rely on coal-fired power generating units to undertake deep peak-shaving tasks in order to improve the overall regulation capacity of the power grid.

[0003] Traditional coal-fired power units have long been designed for base load operation, and their operating characteristics are ill-suited to the demands of frequent start-ups and shutdowns and wide load regulation. Under low load conditions, the unit's thermodynamic parameters deviate from the design point, leading to a significant decrease in power generation efficiency. Simultaneously, limited by boiler thermal inertia, the load response speed is slow, resulting in insufficient flexibility and making it difficult to meet the rapid regulation requirements of modern power systems. Therefore, there is an urgent need for a power generation system that improves its low-load efficiency and regulation performance. Summary of the Invention

[0004] The embodiments of the present invention aim to at least solve one of the technical problems existing in the prior art, and provide a thermal power generation system coupled with a supercritical carbon dioxide cycle.

[0005] This invention provides a thermal power generation system coupled with a supercritical carbon dioxide cycle, comprising: A thermal power unit, comprising a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a low-pressure feedwater heater group, a deaerator, and a high-pressure feedwater heater group connected in sequence to form a steam circulation loop. The extraction steam output end of the low-pressure cylinder is connected to the low-pressure feedwater heater group, and the extraction steam output end of the intermediate-pressure cylinder and the extraction steam output end of the high-pressure cylinder are respectively connected to the high-pressure feedwater heater group. A supercritical carbon dioxide subsystem includes a low-pressure cooler group, a first compressor, a high-pressure heater group, and a first turbine, which are connected in series to form a working fluid circulation loop. The feedwater of the low-pressure feedwater heater group flows through the cold side of the low-pressure cooler group. The extraction steam output end of the intermediate-pressure cylinder, the hot side of the high-pressure heater group, and the hot side of the high-pressure feedwater heater group are connected in sequence, and / or the extraction steam output end of the high-pressure cylinder, the hot side of the high-pressure heater group, and the hot side of the high-pressure feedwater heater group are connected in sequence.

[0006] In some embodiments of the present invention, the low-pressure cooler group includes a first low-pressure cooler and a second low-pressure cooler, the first turbine, the first low-pressure cooler, the second low-pressure cooler and the first compressor are connected in sequence, and the feed water of the low-pressure feed water heater group flows in sequence through the cold side of the first low-pressure cooler and the cold side of the second low-pressure cooler.

[0007] In some embodiments of the present invention, the low-pressure feedwater heater group includes a first low-pressure feedwater heater, a second low-pressure feedwater heater, a third low-pressure feedwater heater, and a fourth low-pressure feedwater heater. The steam output end of the low-pressure cylinder, the cold side of the first low-pressure feedwater heater, the cold side of the first low-pressure cooler, the hot side of the second low-pressure feedwater heater, the cold side of the third low-pressure feedwater heater, the cold side of the second low-pressure cooler, and the cold side of the fourth low-pressure feedwater heater are sequentially connected through low-pressure heating pipelines.

[0008] In some embodiments of the present invention, the high-pressure heater group includes a first high-pressure heater and a second high-pressure heater. The first compressor, the first high-pressure heater, the second high-pressure heater and the first turbine are connected in sequence. The steam extraction output end of the high-pressure cylinder, the hot side of the first high-pressure heater and the hot side of the high-pressure feedwater heater group are connected in sequence. The steam extraction output end of the intermediate-pressure cylinder, the hot side of the second high-pressure heater and the hot side of the high-pressure feedwater heater group are connected in sequence.

[0009] In some embodiments of the present invention, the high-pressure feedwater heater group includes a first high-pressure feedwater heater, a second high-pressure feedwater heater, and a third high-pressure feedwater heater connected in sequence. The output end of the deaerator is connected to the feedwater inlet of the first high-pressure feedwater heater, and the feedwater outlet of the third high-pressure feedwater heater is connected to the feedwater inlet of the boiler. The extraction steam output end of the high-pressure cylinder, the hot side of the first high-pressure heater, and the third high-pressure feedwater heater are connected in sequence. The extraction steam output end of the intermediate-pressure cylinder, the hot side of the second high-pressure heater, and the first high-pressure feedwater heater are connected in sequence.

[0010] In some embodiments of the present invention, the supercritical carbon dioxide subsystem includes: a high-pressure cooler group and a second compressor, wherein the first compressor, the high-pressure cooler group, the second compressor and the high-pressure heater group are connected in sequence, and the feedwater of the low-pressure feedwater heater group flows sequentially through the cold side of the low-pressure cooler group, the cold side of the high-pressure cooler group, and / or the feedwater at the deaerator output flows through the cold side of the high-pressure cooler group.

[0011] In some embodiments of the present invention, the high-pressure cooler group includes a first high-pressure cooler and a second high-pressure cooler, the first compressor, the first high-pressure cooler, the second high-pressure cooler and the second compressor are connected in sequence, the feed water of the low-pressure feed water heater group flows sequentially through the cold side of the low-pressure cooler group and the cold side of the first high-pressure cooler, and the feed water at the deaerator output end flows through the cold side of the second high-pressure cooler and the high-pressure feed water heater group.

[0012] In some embodiments of the present invention, the supercritical carbon dioxide subsystem includes: a low-pressure heater group and a second turbine, wherein the first turbine, the low-pressure heater group, the second turbine, and the low-pressure cooler group are connected in sequence, the steam output end of the intermediate-pressure cylinder, the hot side of the low-pressure heater group, and the deaerator are connected in sequence, and / or the steam output end of the low-pressure cylinder, the hot side of the low-pressure heater group, and the low-pressure feedwater heater group are connected in sequence.

[0013] In some embodiments of the present invention, the low-pressure heater group includes a first low-pressure heater and a second low-pressure heater, the first turbine, the first low-pressure heater, the second low-pressure heater and the second turbine are connected in sequence, the steam output end of the intermediate-pressure cylinder, the hot side of the first low-pressure heater and the deaerator are connected in sequence, and the steam output end of the low-pressure cylinder, the hot side of the second low-pressure heater and the low-pressure feedwater heater group are connected in sequence.

[0014] In some embodiments of the present invention, the low-pressure feedwater heater group includes a first low-pressure feedwater heater, a second low-pressure feedwater heater, a third low-pressure feedwater heater and a fourth low-pressure feedwater heater arranged sequentially along the flow direction of the feedwater, and the steam output end of the low-pressure cylinder, the hot side of the second low-pressure heater and the fourth low-pressure feedwater heater are connected in sequence.

[0015] The thermal power generation system coupled with supercritical carbon dioxide cycle of the present invention adds a supercritical carbon dioxide subsystem to the thermal power unit. The supercritical carbon dioxide subsystem uses the extracted steam of the thermal power unit as a heat source to heat the high-temperature and high-pressure working fluid discharged from the compressor, and uses the feedwater of the thermal power unit as a cold source to cool the lower-temperature and lower-pressure working fluid discharged from the first turbine, thereby improving the power generation efficiency of the supercritical carbon dioxide subsystem. Even when the load response speed of the thermal power unit is slow, the power generation of the entire system can be guaranteed by the supercritical carbon dioxide subsystem, meeting the rapid adjustment requirements of the system. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the thermal power generation system coupled with a supercritical carbon dioxide cycle according to the present invention.

[0017] Figure label: 1. Boiler; 2. High-pressure cylinder; 3. Intermediate-pressure cylinder; 4. Low-pressure cylinder; 5. Generator; 6. Condenser; 7. First low-pressure feedwater heater; 8. Second low-pressure feedwater heater; 9. Third low-pressure feedwater heater; 10. Fourth low-pressure feedwater heater; 11. Deaerator; 12. First high-pressure feedwater heater; 13. Second high-pressure feedwater heater; 14. Third high-pressure feedwater heater; 15. First high-pressure heater; 16. Second high-pressure heater; 17. First turbine; 18. First low-pressure heater; 19. Second low-pressure heater; 20. Second turbine; 21. First low-pressure cooler; 22. Second low-pressure cooler; 23. First high-pressure cooler; 24. Second high-pressure cooler; 25. Second compressor; 26. First compressor. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit disclosure. The described embodiments are some, but not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0019] like Figure 1 As shown, this embodiment of the invention provides a thermal power generation system coupled with a supercritical carbon dioxide cycle, comprising: a thermal power unit, the thermal power unit including a boiler 1, a high-pressure cylinder 2, an intermediate-pressure cylinder 3, a low-pressure cylinder 4, a low-pressure feedwater heater group, a deaerator 11, and a high-pressure feedwater heater group connected in sequence to form a steam circulation loop, the steam extraction output end of the low-pressure cylinder 4 being connected to the low-pressure feedwater heater group, and the steam extraction output ends of the intermediate-pressure cylinder 3 and the high-pressure cylinder 2 being respectively connected to the high-pressure feedwater heater group.

[0020] Specifically, the thermal power unit includes a boiler 1, a high-pressure cylinder 2, an intermediate-pressure cylinder 3, a low-pressure cylinder 4, a low-pressure feedwater heater group, a deaerator 11, and a high-pressure feedwater heater group connected in sequence. High-temperature steam from boiler 1 is transported to high-pressure cylinder 2 through the main steam pipeline to perform work. Steam extracted from high-pressure cylinder 2 enters the reheat device of boiler 1 for reheat treatment. The reheated steam then enters the intermediate-pressure cylinder 3 to perform work. Part of the steam from intermediate-pressure cylinder 3 is transported to low-pressure cylinder 4 and performs work there. After performing work in low-pressure cylinder 4, the steam flows out as feedwater. The feedwater flows sequentially through the cold side of the low-pressure feedwater heater group, the deaerator 11, and the cold side of the high-pressure feedwater heater group, finally returning to boiler 1 through the feedwater inlet. There, it undergoes heating treatment to form high-temperature steam, thus forming the main steam. The steam extraction output end of low-pressure cylinder 4 is connected to the hot side of the low-pressure feedwater heater group to transfer the heat from the extracted steam of low-pressure cylinder 4 to the feedwater flowing through the cold side of the low-pressure feedwater heater group. The extraction steam output end of the intermediate-pressure cylinder 3 is connected to the hot side of the high-pressure feedwater heater group to transfer the heat from the extraction steam of the intermediate-pressure cylinder 3 to the feedwater flowing through the cold side of the high-pressure feedwater heater group. The extraction steam output end of the high-pressure cylinder 2 is also connected to the hot side of the high-pressure feedwater heater group to transfer the heat from the extraction steam of the high-pressure cylinder 2 to the feedwater flowing through the cold side of the high-pressure feedwater heater group. The feedwater discharged from the low-pressure cylinder 4 after performing work flows sequentially through the low-pressure feedwater heater group, the deaerator 11, and the high-pressure feedwater heater group, and is heated sequentially by the low-pressure feedwater heater group and the high-pressure feedwater heater group to increase the temperature of the feedwater flowing into the feedwater inlet of boiler 1, reduce the amount of coal burned in boiler 1, and improve the thermal energy utilization rate.

[0021] A thermal power generation system coupled with a supercritical carbon dioxide cycle includes: a supercritical carbon dioxide subsystem, which includes a low-pressure cooler group, a first compressor 26, a high-pressure heater group, and a first turbine 17 connected in series to form a working fluid circulation loop. The feedwater of the low-pressure feedwater heater group flows through the cold side of the low-pressure cooler group. The extraction steam output end of the intermediate-pressure cylinder 3, the hot side of the high-pressure heater group, and the hot side of the high-pressure feedwater heater group are connected in sequence, and / or the extraction steam output end of the high-pressure cylinder 2, the hot side of the high-pressure heater group, and the hot side of the high-pressure feedwater heater group are connected in sequence.

[0022] Specifically, the supercritical carbon dioxide subsystem includes a low-pressure cooler group, a first compressor 26, a high-pressure heater group, and a first turbine 17 connected in series. The working fluid, carbon dioxide, flows sequentially through the low-pressure cooler group, the first compressor 26, the high-pressure heater group, and the first turbine 17, and returns to the low-pressure cooler group to form a working fluid circulation loop. Feedwater flowing in the low-pressure feedwater heater group passes through the cold side of the low-pressure cooler group to absorb heat from the working fluid flowing through the hot side of the low-pressure cooler group, increasing the feedwater temperature while simultaneously decreasing the working fluid temperature. The extraction steam output end of the intermediate-pressure cylinder 3, the hot side of the high-pressure heater group, and the hot side of the high-pressure feedwater heater group are connected in series. The extraction steam output from the intermediate-pressure cylinder 3 flows sequentially through the hot side of the high-pressure heater group and the hot side of the high-pressure feedwater heater group to heat the working fluid on the cold side of the high-pressure heater group and the feedwater on the cold side of the high-pressure feedwater heater group. Alternatively / and, the extraction steam output end of high-pressure cylinder 2, the hot side of high-pressure heater group, and the hot side of high-pressure feedwater heater group are connected in sequence. The extraction steam output from high-pressure cylinder 2 flows sequentially through the hot side of high-pressure heater group and the hot side of high-pressure feedwater heater group to heat the working fluid on the cold side of high-pressure heater group and the feedwater on the cold side of high-pressure feedwater heater group. The working fluid discharged from the first turbine 17 flows through the hot side of low-pressure cooler group and releases heat to the feedwater on its cold side. After releasing heat, the low-temperature working fluid enters the first compressor 26 for compression. The compressor compresses the working fluid into a high-temperature, high-pressure gas and flows through the cold side of high-pressure heater group, absorbing the heat from the extraction steam on its hot side to further increase the temperature of carbon dioxide gas. The high-temperature, high-pressure carbon dioxide gas enters the first turbine 17 and performs work. After performing work, the working fluid temperature decreases and the pressure decreases, and it enters the hot side of low-pressure cooler group. The supercritical carbon dioxide subsystem uses the extracted steam from the thermal power unit as a heat source to heat the high-temperature and high-pressure working fluid discharged from the compressor, and uses the feedwater from the thermal power unit as a cold source to cool the lower-temperature and lower-pressure working fluid discharged from the first turbine 17, thereby improving the energy utilization rate of the thermal power unit.

[0023] The thermal power generation system coupled with supercritical carbon dioxide cycle of the present invention adds a supercritical carbon dioxide subsystem to the thermal power unit. The supercritical carbon dioxide subsystem uses the extracted steam of the thermal power unit as a heat source to heat the high-temperature and high-pressure working fluid discharged from the compressor, and uses the feedwater of the thermal power unit as a cold source to cool the lower-temperature and lower-pressure working fluid discharged from the first turbine 17, thereby improving the power generation efficiency of the supercritical carbon dioxide subsystem. Even when the load response speed of the thermal power unit is slow, the power generation of the entire system can be guaranteed by the supercritical carbon dioxide subsystem, meeting the rapid adjustment requirements of the system.

[0024] In some embodiments of the present invention, the low-pressure cooler group includes a first low-pressure cooler 21 and a second low-pressure cooler 22. The first turbine 17, the first low-pressure cooler 21, the second low-pressure cooler 22 and the first compressor 26 are connected in sequence. The feed water of the low-pressure feed water heater group flows through the cold side of the first low-pressure cooler 21 and the cold side of the second low-pressure cooler 22 in sequence. The high-temperature, high-pressure working fluid discharged from the first turbine 17 flows sequentially through the hot side of the first low-pressure cooler 21, the hot side of the second low-pressure cooler 22, and the first compressor 26. The working fluid releases heat from the hot side of the first low-pressure cooler 21 to the cold side of the first low-pressure cooler 21 to heat the feedwater of the low-pressure feedwater heater group. After flowing out from the hot side of the first low-pressure cooler 21, the working fluid enters the second low-pressure cooler 22 and releases heat from its hot side to the cold side of the second low-pressure cooler 22 to heat the feedwater of the low-pressure feedwater heater group. After the working fluid exchanges heat with the first low-pressure cooler 21 and the second low-pressure cooler 22, its temperature decreases, and the cooled working fluid enters the first compressor 26. The high-temperature, high-pressure working fluid undergoes two reductions before the first compressor 26 to release its heat into the feedwater of the low-pressure feedwater heater unit of the thermal power unit. This heat is then released into the steam circulation loop of the thermal power unit, increasing the temperature of the feedwater returned to boiler 1, reducing coal consumption, improving the efficiency of high-temperature steam output, and enhancing the unit's response speed. Simultaneously, the thermal power unit absorbs the heat from the supercritical carbon dioxide subsystem's working fluid, reducing the compression power consumption of the first compressor 26, preventing excessively high working fluid temperature after compression, increasing working fluid density, and increasing mass flow rate.

[0025] In some embodiments of the present invention, the low-pressure feedwater heater group includes a first low-pressure feedwater heater 7, a second low-pressure feedwater heater 8, a third low-pressure feedwater heater 9, and a fourth low-pressure feedwater heater 10. The steam output end of the low-pressure cylinder 4, the cold side of the first low-pressure feedwater heater 7, the cold side of the first low-pressure cooler 21, the cold side of the second low-pressure feedwater heater 8, the cold side of the third low-pressure feedwater heater 9, the cold side of the second low-pressure cooler 22, and the cold side of the fourth low-pressure feedwater heater 10 are sequentially connected through low-pressure heating pipelines. Specifically, the feedwater output from the steam output end of the low-pressure cylinder 4 flows sequentially through the cold side of the first low-pressure feedwater heater 7, the cold side of the first low-pressure cooler 21, the cold side of the second low-pressure feedwater heater 8, the cold side of the third low-pressure feedwater heater 9, the cold side of the second low-pressure cooler 22, and the cold side of the fourth low-pressure feedwater heater 10, absorbing heat from the hot-side steam of the first low-pressure feedwater heater 7, the hot-side working fluid of the first low-pressure cooler 21, the hot-side steam of the second low-pressure feedwater heater 8, the hot-side steam of the third low-pressure feedwater heater 9, the hot-side working fluid of the second low-pressure cooler 22, and the hot-side steam of the fourth low-pressure feedwater heater 10. Furthermore, the steam extraction output end of the low-pressure cylinder 4 is connected to the hot-side inlets of the first low-pressure feedwater heater 7, the second low-pressure feedwater heater 8, the third low-pressure feedwater heater 9, and the fourth low-pressure feedwater heater 10, respectively. The hot-side outlet of the fourth low-pressure feedwater heater 10 is connected to the third low-pressure feedwater heater 9. The hot-side outlet of the third low-pressure feedwater heater 9 is connected to the second low-pressure feedwater heater 8. The hot-side outlet of the second low-pressure feedwater heater 8 is connected to the first low-pressure feedwater heater 7. The hot-side outlet of the first low-pressure feedwater heater 7 is connected to the condenser 6. The steam output end of the low-pressure cylinder 4 is connected to the inlet of the condenser 6. The feedwater output from the steam output end of the low-pressure cylinder 4 first enters the condenser 6 and then flows from the outlet of the condenser 6 to the cold side of the first low-pressure feedwater heater 7.

[0026] In some embodiments of the present invention, the high-pressure heater group includes a first high-pressure heater 15 and a second high-pressure heater 16. The first compressor 26, the first high-pressure heater 15, the second high-pressure heater 16 and the first turbine 17 are connected in sequence. The extraction steam output end of the high-pressure cylinder 2, the hot side of the first high-pressure heater 15 and the hot side of the high-pressure feedwater heater group are connected in sequence. The high-temperature steam output from the extraction steam output end of the high-pressure cylinder 2 flows through the hot side of the first high-pressure heater 15 and the hot side of the high-pressure feedwater heater group in sequence. The extraction steam output end of the intermediate-pressure cylinder 3, the hot side of the second high-pressure heater 16 and the hot side of the high-pressure feedwater heater group are connected in sequence. The high-temperature steam output from the extraction steam output end of the intermediate-pressure cylinder 3 flows through the hot side of the first high-pressure heater 15 and the hot side of the high-pressure feedwater heater group in sequence. Specifically, the high-temperature and high-pressure working fluid output by the first compressor 26 flows sequentially through the cold side of the first high-pressure heater 15, the cold side of the second high-pressure heater 16, and the first turbine 17. The high-temperature and high-pressure working fluid absorbs the steam heat from the hot side of the first high-pressure heater 15 on the cold side to increase the temperature of the working fluid. After the temperature rises, the working fluid flows out from the cold side of the first high-pressure heater 15 and enters the cold side of the second high-pressure heater 16 to absorb the steam heat from its hot side to further increase the temperature of the working fluid. The working fluid after the two temperature increases directly or indirectly enters the first turbine 17 to improve the efficiency of the first turbine 17.

[0027] In some embodiments of the present invention, the high-pressure feedwater heater group includes a first high-pressure feedwater heater 12, a second high-pressure feedwater heater 13, and a third high-pressure feedwater heater 14 connected in sequence. The output end of the deaerator 11 is connected to the feedwater inlet of the first high-pressure feedwater heater 12, and the feedwater outlet of the third high-pressure feedwater heater 14 is connected to the feedwater inlet of the boiler 1. Specifically, the feedwater output from the low-pressure feedwater heating container group flows sequentially through the deaerator 11, the cold side of the first high-pressure feedwater heater 12, the cold side of the second high-pressure feedwater heater 13, the cold side of the third high-pressure feedwater heater 14, and the feedwater inlet of the boiler 1. The extraction steam output end of high-pressure cylinder 2, the hot side of the first high-pressure heater 15, and the hot side inlet of the third high-pressure feedwater heater 14 are connected in sequence. The high-temperature steam output from the extraction steam output end of high-pressure cylinder 2 flows sequentially through the hot side of the first high-pressure heater 15 and the hot side of the third high-pressure feedwater heater 14. The extraction steam output end of intermediate-pressure cylinder 3, the hot side of the second high-pressure heater 16, and the hot side inlet of the first high-pressure feedwater heater 12 are connected in sequence. The high-temperature steam output from the extraction steam output end of intermediate-pressure cylinder 3 flows sequentially through the hot side of the second high-pressure heater 16 and the hot side of the first high-pressure feedwater heater 12. The hot side outlet of the third high-pressure feedwater heater 14 is connected to the second high-pressure feedwater heater 13, the hot side outlet of the second high-pressure feedwater heater 13 is connected to the first high-pressure feedwater heater 12, and the hot side outlet of the first high-pressure feedwater heater 12 is connected to the inlet of the deaerator 11.

[0028] It should be noted that in this embodiment, the pressures of the first high-pressure water heater 12, the second high-pressure water heater 13, and the third high-pressure water heater 14 increase sequentially.

[0029] In some embodiments of the present invention, the supercritical carbon dioxide subsystem includes: a high-pressure cooler group and a second compressor 25. A first compressor 26, the high-pressure cooler group, the second compressor 25, and a high-pressure heater group are connected in sequence. The working fluid is compressed into a high-temperature, high-pressure working fluid by the first compressor 26, then transported to the hot side of the high-pressure cooler group to release heat, and then enters the second compressor 25 for further compression into a high-temperature, high-pressure working fluid. The high-temperature, high-pressure working fluid is then transported to the cold side of the high-pressure heater group to absorb heat from the high-temperature steam. Feedwater from the low-pressure feedwater heater group flows sequentially through the cold side of the low-pressure cooler group, the cold side of the high-pressure cooler group, and / or, feedwater from the deaerator 11 output flows through the cold side of the high-pressure cooler group. That is, the high-pressure cooler group can be located between the low-pressure feedwater heater group and the deaerator 11, or between the deaerator 11 and the high-pressure feedwater heater group, or a portion of the high-pressure cooler group can be located between the low-pressure feedwater heater group and the deaerator 11, and another portion can be located between the deaerator 11 and the high-pressure feedwater heater group.

[0030] In some embodiments of the present invention, the high-pressure cooler group includes a first high-pressure cooler 23 and a second high-pressure cooler 24. A first compressor 26, a first high-pressure cooler 23, a second high-pressure cooler 24 and a second compressor 25 are connected in sequence. After the working fluid is compressed into a high-temperature and high-pressure working fluid by the first compressor 26, it flows sequentially through the hot side of the first high-pressure cooler 23, the hot side of the second high-pressure cooler 24 and the second compressor 25. After the working fluid is output from the first compressor 26, it releases heat sequentially to the hot side of the first high-pressure cooler 23 and the hot side of the second high-pressure cooler 24. The feedwater from the low-pressure feedwater heater group flows sequentially through the cold side of the low-pressure cooler group and the cold side of the first high-pressure cooler 23. The feedwater from the deaerator 11 output flows through the cold side of the second high-pressure cooler 24 and the high-pressure feedwater heater group. Specifically, the feedwater output from the steam output end of the low-pressure cylinder 4 flows sequentially through the cold side of the first low-pressure feedwater heater 7, the cold side of the first low-pressure cooler 21, the cold side of the second low-pressure feedwater heater 8, the cold side of the third low-pressure feedwater heater 9, the cold side of the second low-pressure cooler 22, the cold side of the fourth low-pressure feedwater heater 10, the cold side of the first high-pressure cooler 23, the deaerator 11, the cold side of the second high-pressure cooler 24, the cold side of the first high-pressure feedwater heater 12, the cold side of the second high-pressure feedwater heater 13, the cold side of the third high-pressure feedwater heater 14, and the feedwater inlet of the boiler 1.

[0031] In some embodiments of the present invention, the supercritical carbon dioxide subsystem includes: a low-pressure heater group and a second turbine 20. A first turbine 17, the low-pressure heater group, the second turbine 20, and a low-pressure cooler group are connected in sequence. The working fluid is output from the first turbine 17, flows through the cold side of the low-pressure heater group to absorb heat from the steam on the hot side of the low-pressure heater group, and then enters the second turbine 20 to perform work. After performing work, it is delivered to the hot side of the low-pressure cooler group. The steam output end of the intermediate-pressure cylinder 3, the hot side of the low-pressure heater group, and the deaerator 11 are connected in sequence, and / or, the steam output end of the low-pressure cylinder 4, the hot side of the low-pressure heater group, and the low-pressure feedwater heater group are connected in sequence. Specifically, the low-pressure heater group is connected between the output end of the medium-pressure cylinder 3 and the deaerator 11, or the low-pressure heater group is connected between the output end of the low-pressure cylinder 4 and the low-pressure feedwater heater group, or a portion of the low-pressure heater group is connected between the output end of the medium-pressure cylinder 3 and the deaerator 11, and the other portion of the low-pressure heater group is connected between the output end of the low-pressure cylinder 4 and the low-pressure feedwater heater group.

[0032] In some embodiments of the present invention, the low-pressure heater group includes a first low-pressure heater 18 and a second low-pressure heater 19. A first turbine 17, the first low-pressure heater 18, the second low-pressure heater 19, and a second turbine 20 are connected in sequence. The working fluid is output from the first turbine 17, flows sequentially through the cold side of the first low-pressure heater 18 and the cold side of the second low-pressure heater 19, and then enters the second turbine 20 to perform work. After performing work, it is delivered to the hot side of the low-pressure cooler group. The steam output end of the intermediate-pressure cylinder 3, the hot side of the first low-pressure heater 18, and the deaerator 11 are connected in sequence. The extraction steam output from the intermediate-pressure cylinder 3 enters the hot side of the first low-pressure heater 18 to release heat to the working fluid flowing through the cold side of the first low-pressure heater 18. The steam after releasing heat enters the deaerator 11. The steam output end of the low-pressure cylinder 4, the hot side of the second low-pressure heater 19, and the low-pressure feedwater heater group are connected in sequence. The extracted steam output from the low-pressure cylinder 4 enters the hot side of the second low-pressure heater 19 to release heat to the working fluid flowing through the cold side of the second low-pressure heater 19. The steam after releasing heat enters the hot side of the low-pressure feedwater heater group.

[0033] In some embodiments of the present invention, the low-pressure feedwater heater group includes a first low-pressure feedwater heater 7, a second low-pressure feedwater heater 8, a third low-pressure feedwater heater 9, and a fourth low-pressure feedwater heater 10 arranged sequentially along the flow direction of the feedwater. The steam output end of the low-pressure cylinder 4, the hot side of the second low-pressure heater 19, and the fourth low-pressure feedwater heater 10 are connected in sequence. The extracted steam output from the low-pressure cylinder 4 enters the hot side of the second low-pressure heater 19 to release heat to the working fluid flowing through the cold side of the first low-pressure heater 18. The steam after releasing heat enters the hot side of the fourth low-pressure feedwater heater 10 through the hot side inlet.

[0034] It should be noted that in this embodiment, the pressures of the first low-pressure water heater 7, the second low-pressure water heater 8, the third low-pressure water heater 9, and the fourth low-pressure water heater 10 increase sequentially.

[0035] The thermal power unit also includes a generator 5, which is coaxially connected to the high-pressure cylinder 2, the intermediate-pressure cylinder 3, and the low-pressure cylinder 4. The generator generates electricity by the work done by the high-pressure cylinder 2, the intermediate-pressure cylinder 3, and the low-pressure cylinder 4.

[0036] The thermal power generation system coupled with a supercritical carbon dioxide cycle of the present invention has the following beneficial effects: 1. Conventional steam cycles have a thermal efficiency of approximately 45% to 47%. In contrast, the supercritical carbon dioxide cycle used in this invention has a higher thermal efficiency, reaching 47% to 50% overall. By utilizing the higher density and heat exchange performance of carbon dioxide in the supercritical state, the overall compression power consumption of the system is reduced, thereby increasing net power output.

[0037] 2. Supercritical carbon dioxide has a high density and low specific volume, which significantly reduces the volume of system pipes and heat exchangers for the same power, thereby reducing the system footprint and material costs, and facilitating modular system design and rapid deployment.

[0038] 3. This design utilizes a traditional coal-fired boiler as a heat source, eliminating the need to completely replace existing infrastructure. This facilitates the upgrading and transformation of coal-fired power systems and allows for a smooth transition from traditional steam systems to a new generation of carbon dioxide cycles through a coupling mechanism.

[0039] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A thermal power generating system coupled with a supercritical carbon dioxide cycle, characterized by, include: A thermal power unit, comprising a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a low-pressure feedwater heater group, a deaerator, and a high-pressure feedwater heater group connected in sequence to form a steam circulation loop. The extraction steam output end of the low-pressure cylinder is connected to the low-pressure feedwater heater group, and the extraction steam output end of the intermediate-pressure cylinder and the extraction steam output end of the high-pressure cylinder are respectively connected to the high-pressure feedwater heater group. A supercritical carbon dioxide subsystem includes a low-pressure cooler group, a first compressor, a high-pressure heater group, and a first turbine, which are connected in series to form a working fluid circulation loop. The feedwater of the low-pressure feedwater heater group flows through the cold side of the low-pressure cooler group. The extraction steam output end of the intermediate-pressure cylinder, the hot side of the high-pressure heater group, and the hot side of the high-pressure feedwater heater group are connected in sequence, and / or the extraction steam output end of the high-pressure cylinder, the hot side of the high-pressure heater group, and the hot side of the high-pressure feedwater heater group are connected in sequence.

2. The coal-fired power generating system coupled with a supercritical carbon dioxide cycle according to claim 1, characterized by, The low-pressure cooler group includes a first low-pressure cooler and a second low-pressure cooler. The first turbine, the first low-pressure cooler, the second low-pressure cooler and the first compressor are connected in sequence. The feed water of the low-pressure feed water heater group flows sequentially through the cold side of the first low-pressure cooler and the cold side of the second low-pressure cooler.

3. The coal-fired power generating system coupled with a supercritical carbon dioxide cycle according to claim 2, characterized by, The low-pressure feedwater heater group includes a first low-pressure feedwater heater, a second low-pressure feedwater heater, a third low-pressure feedwater heater, and a fourth low-pressure feedwater heater. The steam output end of the low-pressure cylinder, the cold side of the first low-pressure feedwater heater, the cold side of the first low-pressure cooler, the hot side of the second low-pressure feedwater heater, the cold side of the third low-pressure feedwater heater, the cold side of the second low-pressure cooler, and the cold side of the fourth low-pressure feedwater heater are connected sequentially through low-pressure heating pipelines.

4. The thermal power generation system coupled with a supercritical carbon dioxide cycle according to claim 1, characterized in that, The high-pressure heater group includes a first high-pressure heater and a second high-pressure heater. The first compressor, the first high-pressure heater, the second high-pressure heater and the first turbine are connected in sequence. The steam extraction output end of the high-pressure cylinder, the hot side of the first high-pressure heater and the hot side of the high-pressure feedwater heater group are connected in sequence. The steam extraction output end of the intermediate-pressure cylinder, the hot side of the second high-pressure heater and the hot side of the high-pressure feedwater heater group are connected in sequence.

5. The thermal power generation system coupled with a supercritical carbon dioxide cycle according to claim 4, characterized in that, The high-pressure feedwater heater group includes a first high-pressure feedwater heater, a second high-pressure feedwater heater, and a third high-pressure feedwater heater connected in sequence. The output end of the deaerator is connected to the feedwater inlet of the first high-pressure feedwater heater, and the feedwater outlet of the third high-pressure feedwater heater is connected to the feedwater inlet of the boiler. The extraction steam output end of the high-pressure cylinder, the hot side of the first high-pressure heater, and the third high-pressure feedwater heater are connected in sequence. The extraction steam output end of the intermediate-pressure cylinder, the hot side of the second high-pressure heater, and the first high-pressure feedwater heater are connected in sequence.

6. The thermal power generation system coupled with a supercritical carbon dioxide cycle according to claim 1, characterized in that, The supercritical carbon dioxide subsystem includes a high-pressure cooler group and a second compressor. The first compressor, the high-pressure cooler group, the second compressor and the high-pressure heater group are connected in sequence. The feed water of the low-pressure feed water heater group flows sequentially through the cold side of the low-pressure cooler group, the cold side of the high-pressure cooler group, and / or the feed water at the deaerator output flows through the cold side of the high-pressure cooler group.

7. The thermal power generation system coupled with a supercritical carbon dioxide cycle according to claim 6, characterized in that, The high-pressure cooler group includes a first high-pressure cooler and a second high-pressure cooler. The first compressor, the first high-pressure cooler, the second high-pressure cooler and the second compressor are connected in sequence. The feedwater of the low-pressure feedwater heater group flows sequentially through the cold side of the low-pressure cooler group and the cold side of the first high-pressure cooler. The feedwater at the deaerator output flows through the cold side of the second high-pressure cooler and the high-pressure feedwater heater group.

8. The thermal power generation system coupled with a supercritical carbon dioxide cycle according to claim 1, characterized in that, The supercritical carbon dioxide subsystem includes: a low-pressure heater group and a second turbine, wherein the first turbine, the low-pressure heater group, the second turbine, and the low-pressure cooler group are connected in sequence, the steam output end of the intermediate-pressure cylinder, the hot side of the low-pressure heater group, and the deaerator are connected in sequence, and / or the steam output end of the low-pressure cylinder, the hot side of the low-pressure heater group, and the low-pressure feedwater heater group are connected in sequence.

9. The thermal power generation system coupled with a supercritical carbon dioxide cycle according to claim 8, characterized in that, The low-pressure heater group includes a first low-pressure heater and a second low-pressure heater. The first turbine, the first low-pressure heater, the second low-pressure heater and the second turbine are connected in sequence. The steam output end of the intermediate-pressure cylinder, the hot side of the first low-pressure heater and the deaerator are connected in sequence. The steam output end of the low-pressure cylinder, the hot side of the second low-pressure heater and the low-pressure feedwater heater group are connected in sequence.

10. The thermal power generation system coupled with a supercritical carbon dioxide cycle according to claim 9, characterized in that, The low-pressure feedwater heater group includes a first low-pressure feedwater heater, a second low-pressure feedwater heater, a third low-pressure feedwater heater, and a fourth low-pressure feedwater heater arranged sequentially along the flow direction of the feedwater. The steam output end of the low-pressure cylinder, the hot side of the second low-pressure heater, and the fourth low-pressure feedwater heater are connected in sequence.

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