Thermal power generating unit energy storage system based on fused salt-thermochemical coupling and operation method of thermal power generating unit energy storage system

Abstract

The invention discloses a thermal power generating unit energy storage system based on fused salt-thermochemical coupling and an operation method thereof, and relates to the technical field of energy storage, the thermal power generating unit energy storage system comprises: a thermal power generation system having a first steam generation flow path and a second steam generation flow path; a thermochemical heat storage material is arranged in the thermochemical heat storage reactor, the first heat exchanger is located in the thermochemical heat storage reactor to exchange heat with the thermochemical heat storage material, the second heat exchanger comprises a fused salt flow path and a steam flow path, and the steam flow path is connected to the second steam generation flow path in series. The steam generation heat exchanger assembly is provided with a first heat exchange channel and a second heat exchange channel which exchange heat with each other, the fused salt flow path, the first heat exchanger and the first heat exchange channel communicate, and the second heat exchange channel is connected to the first steam generation flow path in series. The thermal power generating unit energy storage system has the advantages of low cost, high response speed, long service life, high-temperature heat release and flexible temperature regulation and control, and the investment cost and the engineering complexity are effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and more specifically, to an energy storage system for thermal power units based on molten salt-thermochemical coupling and its operation method. Background Technology

[0002] Against the backdrop of energy structure transformation, thermal power units are gradually shifting from baseload power sources to flexible adjustable power sources, making the demand for long-term energy storage and flexible heat release technologies increasingly urgent.

[0003] Among related technologies, thermal storage methods include sensible heat storage and thermochemical energy storage. Sensible heat storage, represented by molten salt tanks, has high technological maturity and relatively low cost, and has achieved megawatt-level applications. However, its energy density is limited, and its discharge temperature is prone to decay. Thermochemical heat storage (TCES) has the advantages of high energy density, low heat loss, and long-term storage. However, TCES suffers from high capital costs, complex reactors, slow kinetic response, and insufficient cycle stability, making it difficult to achieve large-scale, low-cost applications. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one objective of this invention is to propose an energy storage system for thermal power units based on molten salt-thermochemical coupling. This system offers advantages such as low cost, fast response speed, and long lifespan, as well as advantages in high-temperature heat release and flexible temperature control, effectively reducing investment costs and engineering complexity.

[0005] Another objective of this invention is to provide an operation method for a thermal power unit energy storage system based on the above-mentioned molten salt-thermochemical coupling.

[0006] According to an embodiment of the present invention, a thermal power unit energy storage system based on molten salt-thermochemical coupling includes: a thermal power generation system having a first steam generation flow path and a second steam generation flow path; and a coupled thermal storage system, which includes a molten salt thermal storage system and a thermochemical thermal storage system. The thermochemical thermal storage system includes a thermochemical thermal storage reactor and a first heat exchanger. The thermochemical thermal storage reactor is provided with thermochemical thermal storage material. The first heat exchanger is located in the thermochemical thermal storage reactor to exchange heat with the thermochemical thermal storage material. The molten salt thermal storage system includes a second heat exchanger and a steam generation heat exchanger assembly. The second heat exchanger includes a molten salt flow path and a steam flow path. The steam flow path is connected in series with the second steam generation flow path. The steam generation heat exchanger assembly has a first heat exchange channel and a second heat exchange channel that exchange heat with each other. The molten salt flow path, the first heat exchanger, and the first heat exchange channel are sequentially connected. The second heat exchange channel is connected in series with the first steam generation flow path.

[0007] According to an embodiment of the present invention, a thermal power unit energy storage system based on molten salt-thermal chemical coupling is provided. A thermochemical thermal storage material is installed within a thermochemical thermal storage reactor. A first heat exchanger is located within the thermochemical thermal storage reactor to exchange heat with the thermochemical thermal storage material. The molten salt thermal storage system includes a second heat exchanger and a steam generating heat exchanger assembly. The second heat exchanger includes a molten salt flow path and a steam flow path, with the steam flow path connected in series with the second steam generating flow path. The steam generating heat exchanger assembly has a first heat exchange channel and a second heat exchange channel that exchange heat with each other. The molten salt flow path, the first heat exchanger, and the first heat exchange channel are sequentially connected, and the second heat exchange channel is connected in series with the first steam generating flow path. This enables the thermal power unit energy storage system to flexibly adjust the absorption of off-peak electricity and the feedback of peak electricity, improving the peak-shaving and frequency regulation capabilities and flexibility of the thermal power generation system. It also possesses the advantages of low cost, fast response speed, and long lifespan of molten salt thermal storage, as well as the advantages of thermochemical thermal storage in high-temperature heat release and flexible temperature control, effectively reducing the investment cost and engineering complexity of the thermal power unit energy storage system.

[0008] In addition, the thermal power unit energy storage system based on molten salt-thermochemical coupling according to the above embodiments of the present invention may also have the following additional technical features: According to some embodiments of the present invention, a thermal power unit energy storage system based on molten salt-thermochemical coupling is provided. The first heat exchanger has a first inlet, a first outlet, a second inlet, and a second outlet. The molten salt thermal storage system further includes: a first molten salt storage tank, a second molten salt storage tank, a first molten salt pump, and a second molten salt pump; a first molten salt flow path, wherein the first molten salt storage tank, the first molten salt pump, the molten salt flow path, the first inlet, the first heat exchanger, the first outlet, and the second molten salt storage tank are connected in series on the first molten salt flow path, and the first inlet and the first outlet are respectively provided with a first valve and a second valve; a second molten salt flow path, wherein the second molten salt storage tank, the second molten salt pump, the second inlet, the first heat exchanger, the second outlet, the first heat exchange channel, and the first molten salt storage tank are connected in series on the second molten salt flow path, and the second inlet and the second outlet are respectively provided with a third valve and a fourth valve.

[0009] According to some embodiments of the present invention, the first heat exchange channel includes a first sub-molten salt flow path, a second sub-molten salt flow path, and a third sub-molten salt flow path that are interconnected; the second heat exchange channel includes a first sub-steam flow path, a second sub-steam flow path, and a third sub-steam flow path that are interconnected; and the steam generating heat exchanger assembly includes: a superheater, wherein the first sub-molten salt flow path and the first sub-steam flow path are located in the superheater; an evaporator, wherein the second sub-molten salt flow path and the second sub-steam flow path are located in the evaporator; and a preheater, wherein the third sub-molten salt flow path and the third sub-steam flow path are located in the preheater.

[0010] According to some embodiments of the present invention, the thermal power unit energy storage system has a heat storage stage and a heat release stage. The thermochemical heat storage system further includes: a water vapor partial pressure control device, which is used to adjust the water vapor partial pressure in the thermochemical heat storage reactor; and an evaporation and condensation device, which is used to collect water vapor generated by the decomposition of the thermochemical heat storage material in the heat storage stage, or to provide water vapor to the thermochemical heat storage material in the heat release stage.

[0011] According to some embodiments of the present invention, the thermal power generation system includes: a boiler having a feedwater inlet and a main steam outlet, wherein one end of the first steam generation flow path is connected to the feedwater inlet and the other end is connected to the main steam outlet.

[0012] According to some embodiments of the present invention, the thermal power generation system further includes: a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a condenser, and a deaerator; a high-pressure heater group, the high-pressure heater group including a first high-pressure heater, a second high-pressure heater, and a third high-pressure heater; a low-pressure heater group, the low-pressure heater group including a fifth low-pressure heater, a sixth low-pressure heater, a seventh low-pressure heater, and an eighth low-pressure heater; and a circulating water pump, the circulating water pump including a condensate pump and a feedwater pump, wherein the high-pressure cylinder, the intermediate-pressure cylinder, the low-pressure cylinder, the condenser, the condensate pump, the low-pressure heater group, the deaerator, the feedwater pump, the high-pressure heater group, and the boiler are connected.

[0013] According to some embodiments of the present invention, the steam flow path has a third inlet and a third outlet, the third inlet and the first high-pressure heater are both connected to the extraction port of the high-pressure cylinder, and the third outlet is connected to at least one of the inlet of the deaerator and an external heat user.

[0014] According to some embodiments of the present invention, the energy storage system of the thermal power unit further includes: a regulating valve, the regulating valve including a first port, a second port and a third port, the first port being connected to an external heat user, the second port being connected to the main steam outlet, the third port being connected to the first steam flow path, and the third port being selectively connected to at least one of the first port and the second port.

[0015] An operation method for a thermal power unit energy storage system based on molten salt-thermochemical coupling according to an embodiment of the present invention, wherein the thermal power unit energy storage system based on molten salt-thermochemical coupling is the thermal power unit energy storage system based on molten salt-thermochemical coupling according to an embodiment of the present invention, the thermal power unit energy storage system having a heat storage stage and a heat release stage, the operation method comprising: When the required power generation load of the thermal power generation system is lower than the preset power generation, the thermal power unit energy storage system enters the thermal storage stage. Open the first and second valves, close the third and fourth valves, and the first molten salt pump drives the molten salt to flow from the first molten salt storage tank through the molten salt flow path and the first heat exchanger and into the second molten salt storage tank. The water vapor generated by the thermochemical thermal storage reactor enters the evaporation and condensation device for condensation and storage. When the required power generation load of the thermal power generation system is higher than the preset power generation, the energy storage system of the thermal power unit enters the heat release stage; Open the third and fourth valves, close the first and second valves, and the water vapor released by the evaporation and condensation device enters the thermochemical thermal storage reactor. The second molten salt pump drives the molten salt from the second molten salt tank through the first heat exchanger and the first heat exchange channel and into the first molten salt tank.

[0016] According to the embodiment of the present invention, the operation method of the thermal power unit energy storage system based on molten salt-thermochemical coupling involves a thermochemical thermal storage reactor containing thermochemical thermal storage material. A first heat exchanger is located inside the thermochemical thermal storage reactor to exchange heat with the thermochemical thermal storage material. The molten salt thermal storage system includes a second heat exchanger and a steam generating heat exchanger assembly. The second heat exchanger includes a molten salt flow path and a steam flow path, with the steam flow path connected in series in the second steam generating flow path. The steam generating heat exchanger assembly has a first heat exchange channel and a second heat exchange channel that exchange heat with each other. The molten salt flow path, the first heat exchanger, and the first heat exchange channel are connected in sequence, and the second heat exchange channel is connected in series in the first steam generating flow path. This enables the thermal power unit energy storage system to achieve flexible adjustment of low-valley electricity absorption and peak-hour electricity feedback, improving the peak-shaving and frequency regulation capabilities and flexibility of the thermal power generation system. It also has the advantages of low cost, fast response speed, and long lifespan of molten salt thermal storage, as well as the advantages of thermochemical thermal storage in high-temperature heat release and flexible temperature control, effectively reducing the investment cost and engineering complexity of the thermal power unit energy storage system.

[0017] According to some embodiments of the present invention, the operating method further includes: When the thermal power unit energy storage system enters the thermal storage stage, the water vapor partial pressure control device is controlled to reduce the water vapor partial pressure in the thermochemical thermal storage reactor. When the thermal power unit's energy storage system enters the heat release stage, the water vapor partial pressure control device is controlled to increase the water vapor partial pressure in the thermochemical thermal storage reactor.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1This is a schematic diagram of a thermal power unit energy storage system according to an embodiment of the present invention.

[0020] Figure label: 100. Energy storage systems for thermal power units; 200. External heat users; 10. Thermal power generation system; 11. First steam generation path; 12. Second steam generation path; 13. Boiler; 14. High-pressure cylinder; 15. Intermediate-pressure cylinder; 16. Low-pressure cylinder; 17. Condenser; 18. Deaerator; 19. Circulating water pump; 131. Feedwater inlet; 132. Main steam outlet; 191. Condensate pump; 192. Feedwater pump; 20. Coupled thermal storage system; 30. Molten salt thermal storage system; 31. Second heat exchanger; 32. Steam generating heat exchanger assembly; 33. First molten salt storage tank; 34. Second molten salt storage tank; 35. First molten salt pump; 36. Second molten salt pump; 37. First molten salt flow path; 38. Second molten salt flow path; 311. Molten salt flow path; 312. Third inlet; 313. Third outlet; 321. First heat exchange passage; 322. Superheater; 323. Evaporator; 324. Preheater; 40. Thermochemical thermal storage system; 41. Thermochemical thermal storage reactor; 42. First heat exchanger; 43. Water vapor partial pressure control device; 44. Evaporation and condensation device; 411. Thermochemical thermal storage material; 421. First inlet; 422. First outlet; 423. Second inlet; 424. Second outlet; 51. First valve; 52. Second valve; 53. Third valve; 54. Fourth valve; 61. First sub-molten salt flow path; 62. Second sub-molten salt flow path; 63. Third sub-molten salt flow path; 71. High-pressure heater group; 72. Low-pressure heater group; 711. First high-pressure heater; 712. Second high-pressure heater; 713. Third high-pressure heater; 721. Fifth low-pressure heater; 722. Sixth low-pressure heater; 723. Seventh low-pressure heater; 724. Eighth low-pressure heater; 81. Regulating valve; 82. Generator; 811. First port; 812. Second port; 813. Third port. Detailed Implementation

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

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] In the description of this invention, "first feature" and "second feature" may include one or more of the features, "multiple" means two or more, "above" or "below" the second feature may include the first and second features being in direct contact, or the first and second features being in contact through another feature between them, and "above," "over," and "on top" the second feature may include the first feature being directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher horizontal level than the second feature.

[0024] The following description, with reference to the accompanying drawings, describes an embodiment of a thermal power unit energy storage system 100 based on molten salt-thermochemical coupling according to the present invention.

[0025] Reference Figure 1 As shown, the thermal power unit energy storage system 100 based on molten salt-thermal chemical coupling according to an embodiment of the present invention may include: a thermal power generation system 10 and a coupled thermal storage system 20.

[0026] Specifically, the thermal power generation system 10 has a first steam generation flow path 11 and a second steam generation flow path 12. The coupled thermal storage system 20 includes a molten salt thermal storage system 30 and a thermochemical thermal storage system 40. The thermochemical thermal storage system 40 includes a thermochemical thermal storage reactor 41 and a first heat exchanger 42. The thermochemical thermal storage reactor 41 is equipped with a thermochemical thermal storage material 411. The first heat exchanger 42 is located inside the thermochemical thermal storage reactor 41 and can exchange heat with the thermochemical thermal storage material 411. The molten salt thermal storage system 30 includes a second heat exchanger 31 and a steam generation heat exchanger assembly 32. The second heat exchanger 31 includes a molten salt flow path 311 and a steam flow path. The steam flow path is connected in series with the second steam generation flow path 12. The steam generation heat exchanger assembly 32 has a first heat exchange channel 321 and a second heat exchange channel that exchange heat with each other. The molten salt flow path 311, the first heat exchanger 42, and the first heat exchange channel 321 are connected in sequence. The second heat exchange channel is connected in series with the first steam generation flow path 11.

[0027] Therefore, when the power generation load of the thermal power generation system 10 is lower than the minimum power generation, the molten salt flowing through the molten salt flow path 311 can absorb the heat of the steam flow path, that is, the molten salt can absorb the heat of the thermal power generation system 10. After absorbing the heat, the molten salt can enter the first heat exchanger 42, so that the molten salt heats the thermochemical heat storage material 411, effectively storing the heat in the thermochemical heat storage system 40, and completing the heat storage stage.

[0028] When the power generation load of the thermal power generation system 10 is higher than the minimum power generation capacity, the heat stored in the thermochemical thermal storage system 40 is released into the thermochemical thermal storage reactor 41. The thermochemical thermal storage material 411 can heat the molten salt in the first heat exchanger 42, thereby increasing the temperature of the molten salt. The molten salt, after the temperature is increased, flows through the first heat exchange channel 321 and can exchange heat with the water vapor in the second heat exchange channel, thereby increasing the heat of the water vapor in the first steam generation flow path 11. For example, the temperature of the molten salt is increased to generate high-quality steam and send it into the main steam pipe of the boiler 13, effectively improving the output capacity and peak-shaving / frequency regulation response speed of the thermal power generation system 10 during peak power periods, and completing the heat release stage.

[0029] Therefore, the thermal power unit energy storage system 100 of the present invention can reduce power generation output by extracting steam from the thermal power generation system 10 during off-peak hours and supply heat to the thermal power generation system 10 during peak hours to enhance peak capacity. It can achieve flexible adjustment of off-peak electricity absorption and peak electricity feedback, which is beneficial to improving the peak regulation and frequency regulation capabilities of the thermal power generation system 10.

[0030] Meanwhile, the coupled thermal storage system 20 uses molten salt thermal storage as the main energy storage carrier, and thermochemical thermal storage is only used to increase the temperature of molten salt during the heat release stage. This not only leverages the advantages of molten salt thermal storage in terms of low cost, fast response speed and long life, but also has the advantages of thermochemical thermal storage in terms of high-temperature heat release and flexible temperature control. This effectively reduces the investment cost and engineering complexity of the thermal power unit energy storage system 100. Furthermore, the temperature of heat storage and release can be controlled by utilizing the reaction balance principle, realizing the conversion between medium-temperature energy storage and high-temperature heat release, and improving the flexibility of the thermal power unit energy storage system 100.

[0031] In some embodiments, the thermochemical thermal storage material 411 is Ca(OH)2 / CaO, which has high energy storage density, low cost, environmental friendliness, good reversibility, wide operating temperature range and long-term energy storage capacity, and can meet the required usage requirements.

[0032] According to an embodiment of the present invention, a thermal power unit energy storage system 100 based on molten salt-thermal chemical coupling includes a thermochemical thermal storage material 411 disposed within a thermochemical thermal storage reactor 41. A first heat exchanger 42 is located within the thermochemical thermal storage reactor 41 to exchange heat with the thermochemical thermal storage material 411. The molten salt thermal storage system 30 includes a second heat exchanger 31 and a steam generating heat exchanger assembly 32. The second heat exchanger 31 includes a molten salt flow path 311 and a steam flow path. The steam flow path is connected in series with the second steam generating flow path 12. The steam generating heat exchanger assembly 32 has a first heat exchange channel 321 for mutual heat exchange. The second heat exchange channel, molten salt flow path 311, first heat exchanger 42 and first heat exchange channel 321 are connected in sequence, and the second heat exchange channel is connected in series on the first steam generation flow path 11, so that the thermal power unit energy storage system 100 can realize flexible adjustment of low-valley electricity absorption and peak electricity feedback, improve the peak-shaving and frequency regulation capability and flexibility of the thermal power generation system 10, and at the same time have the advantages of low cost, fast response speed and long life of molten salt thermal storage, as well as the advantages of thermochemical thermal storage in high-temperature heat release and flexible temperature control, effectively reducing the investment cost and engineering complexity of the thermal power unit energy storage system 100.

[0033] In some embodiments of the present invention, such as Figure 1 As shown, the first heat exchanger 42 has a first inlet 421, a first outlet 422, a second inlet 423, and a second outlet 424. The molten salt thermal storage system 30 also includes a first molten salt tank 33, a second molten salt tank 34, a first molten salt pump 35, a second molten salt pump 36, a first molten salt flow path 37, and a second molten salt flow path 38. The first molten salt tank 33, the first molten salt pump 35, the molten salt flow path 311, the first inlet 421, the first heat exchanger 42, the first outlet 422, and the second outlet 424 are also described. Two molten salt storage tanks 34 are connected in series on the first molten salt flow path 37. The first inlet 421 and the first outlet 422 are respectively equipped with a first valve 51 and a second valve 52. The second molten salt storage tank 34, the second molten salt pump 36, the second inlet 423, the first heat exchanger 42, the second outlet 424, the first heat exchange channel 321 and the first molten salt storage tank 33 are connected in series on the second molten salt flow path 38. The second inlet 423 and the second outlet 424 are respectively equipped with a third valve 53 and a fourth valve 54.

[0034] When the power generation load of the thermal power generation system 10 is lower than the minimum power generation capacity, the first valve 51 and the second valve 52 are opened, and the third valve 53 and the fourth valve 54 are closed. The first molten salt pump 35 drives molten salt from the first molten salt storage tank 33 through the molten salt flow path 311. The molten salt flowing through the molten salt flow path 311 can absorb the heat from the steam flow path. After absorbing the heat, the molten salt can enter the first heat exchanger 42, so that the molten salt heats the thermochemical heat storage material 411, effectively storing the heat in the thermochemical heat storage system 40, completing the heat storage stage. At the same time, the molten salt after heat exchange enters the second molten salt storage tank 34 for storage. When the required power generation load of the thermal power generation system 10 exceeds the minimum power generation capacity, the third valve 53 and the fourth valve 54 are opened, and the first valve 51 and the second valve 52 are closed. The heat stored in the thermochemical thermal storage system 40 is released into the thermochemical thermal storage reactor 41. The second molten salt pump 36 drives the molten salt from the second molten salt storage tank 34 through the first heat exchanger 42. The thermochemical thermal storage material 411 can heat the molten salt in the first heat exchanger 42, thereby increasing the temperature of the molten salt. The molten salt with increased temperature flows through the first heat exchange channel 321 and can exchange heat with the water vapor in the second heat exchange channel, thereby increasing the heat of the water vapor in the first steam generation flow path 11. At the same time, the molten salt after heat exchange enters the first molten salt storage tank 33 for storage.

[0035] Therefore, the molten salt thermal storage system 30 has a simple structure and is easy to control. Furthermore, by controlling the first valve 51, the second valve 52, the third valve 53, and the fourth valve 54 respectively, the thermal storage and thermal release temperatures can be flexibly adjusted to meet the required molten salt flow. The system is easy to control and can reduce the production cost of the molten salt thermal storage system 30.

[0036] According to some embodiments of the present invention, such as Figure 1 As shown, the first heat exchange channel 321 includes a first sub-molten salt flow path 61, a second sub-molten salt flow path 62, and a third sub-molten salt flow path 63 that are interconnected. The second heat exchange channel includes a first sub-steam flow path, a second sub-steam flow path, and a third sub-steam flow path that are interconnected. The steam generating heat exchanger assembly 32 includes a superheater 322, an evaporator 323, and a preheater 324. The first sub-molten salt flow path 61 and the first sub-steam flow path are located in the superheater 322, the second sub-molten salt flow path 62 and the second sub-steam flow path are located in the evaporator 323, and the third sub-molten salt flow path 63 and the third sub-steam flow path are located in the evaporator 324. The molten salt flowing out of the first heat exchanger 42 can enter the first sub-molten salt flow path 61, the second sub-molten salt flow path 62 and the third sub-molten salt flow path 63 respectively, so that heat exchange can be achieved separately through the superheater 322, the evaporator 323 and the preheater 324. At the same time, the water vapor flowing from the thermal power generation system 10 to the steam generating heat exchanger assembly 32 can enter the third sub-steam flow path, the second sub-steam flow path and the first sub-steam flow path respectively, so that the water vapor can be heated by passing through the preheater 324, the evaporator 323 and the superheater 322 in sequence, ensuring good heating effect.

[0037] In some embodiments of the present invention, such as Figure 1As shown, the thermal power unit energy storage system 100 has a heat storage stage and a heat release stage. The thermochemical heat storage system 40 also includes an evaporation and condensation device 44. The evaporation and condensation device 44 can collect water vapor generated by the decomposition of the thermochemical heat storage material 411 during the heat storage stage, and can store heat to meet the required storage needs. Alternatively, the evaporation and condensation device 44 can provide water vapor to the thermochemical heat storage material 411 during the heat release stage, so that the water vapor released by the evaporation and condensation device 44 can enter the thermochemical heat storage reactor 41 and react with the thermochemical heat storage material 411 (e.g., CaO) to release heat, heat the molten salt in the first heat exchanger 42, and achieve the temperature increase of the molten salt, thereby meeting the heat storage and heat release requirements of the thermochemical heat storage system 40.

[0038] In addition, such as Figure 1 As shown, the thermochemical thermal storage system 40 also includes a water vapor partial pressure control device 43. The water vapor partial pressure control device 43 can adjust the water vapor partial pressure in the thermochemical thermal storage reactor 41, thereby flexibly controlling the heat absorption and release temperature of the thermochemical thermal storage material 411, effectively controlling the heat storage in the heat storage stage and the heat release in the heat release stage, making the operation of the thermal power unit energy storage system 100 more flexible.

[0039] According to some embodiments of the present invention, such as Figure 1 As shown, the thermal power generation system 10 includes a boiler 13, which has a feedwater inlet 131 and a main steam outlet 132. One end of the first steam generation flow path 11 is connected to the feedwater inlet 131, and the other end of the first steam generation flow path 11 is connected to the main steam outlet 132, so that the steam flowing out from the main steam outlet 132 can be converted into superheated steam through the steam generation heat exchanger assembly 32. The superheated steam can enter the main steam pipe of the boiler 13 through the feedwater inlet 131, effectively improving the output capacity and peak shaving / frequency regulation response speed of the thermal power generation system 10 during peak power periods.

[0040] In some embodiments of the present invention, such as Figure 1As shown, the thermal power generation system 10 also includes a high-pressure cylinder 14, an intermediate-pressure cylinder 15, a low-pressure cylinder 16, a condenser 17, a deaerator 18, a high-pressure heater group 71, a low-pressure heater group 72, and a circulating water pump 19. The high-pressure heater group 71 includes a first high-pressure heater 711, a second high-pressure heater 712, and a third high-pressure heater 713. The low-pressure heater group 72 includes a fifth low-pressure heater 721, a sixth low-pressure heater 722, a seventh low-pressure heater 723, and an eighth low-pressure heater 724. The circulating water pump 19 includes a condensate pump. Water pump 191 and feedwater pump 192, high-pressure cylinder 14, medium-pressure cylinder 15, low-pressure cylinder 16, condenser 17, condensate pump 191, low-pressure heater group 72, deaerator 18, feedwater pump 192, high-pressure heater group 71 and boiler 13 are connected, so that high-pressure cylinder 14, medium-pressure cylinder 15, low-pressure cylinder 16, boiler 13, condenser 17, high-pressure heater group 71, low-pressure heater group 72 and deaerator 18 are connected in sequence to form a steam-water circulation, which meets the working requirements of thermal power generation system 10, thereby realizing the power generation of generator 82.

[0041] According to some embodiments of the present invention, such as Figure 1 As shown, the steam flow path has a third inlet 312 and a third outlet 313. The third inlet 312 and the first high-pressure heater 711 are both connected to the steam extraction port of the high-pressure cylinder 14, so that the steam flowing out of the high-pressure cylinder 14 can flow to the steam flow path and the first high-pressure heater 711 to meet the required heat exchange requirements. The third outlet 313 is connected to at least one of the inlet of the deaerator 18 and the external heat user 200. That is, the third outlet 313 is connected to the inlet of the deaerator 18 to realize steam-water circulation, or the third outlet 313 is connected to the external heat user 200 to meet the heating requirements of the external heat user 200, or the third outlet 313 is connected to both the inlet of the deaerator 18 and the external heat user 200 to meet the required connection requirements. It can be set according to the actual situation to meet different usage requirements.

[0042] In some embodiments of the present invention, such as Figure 1 As shown, the thermal power unit energy storage system 100 also includes a regulating valve 81, which includes a first port 811, a second port 812 and a third port 813. The first port 811 is connected to an external heat user 200, the second port 812 is connected to the main steam outlet 132, and the third port 813 is connected to the first steam generation flow path 11. The third port 813 can be selectively connected to at least one of the first port 811 and the second port 812.

[0043] Therefore, when the third port 813 is connected to the first port 811, the steam after heat exchange with the steam generator heat exchanger assembly 32 can flow to the external heat user 200 to meet the heating demand; when the third port 813 is connected to the second port 812, the steam after heat exchange with the steam generator heat exchanger assembly 32 can flow to the thermal power generation system 10, effectively improving the output capacity and peak-shaving / frequency regulation response speed of the thermal power generation system 10 during peak power periods; when the third port 813 is connected to the first port 811 and the second port 812, the thermal power unit energy storage system 100 can enter the combined heat and power mode to meet both heating and power generation needs, and the regulating valve 81 can be controlled according to the actual situation to meet different usage needs, making control more convenient.

[0044] According to an embodiment of the present invention, the operation method of the thermal power unit energy storage system 100 based on molten salt-thermochemical coupling is an embodiment of the present invention, the thermal power unit energy storage system 100 has a heat storage stage and a heat release stage.

[0045] The operation methods include: When the required power generation load of the thermal power generation system 10 is lower than the preset power generation, the thermal power unit energy storage system 100 enters the thermal storage stage, for example, when the preset power generation is the minimum power generation. Open the first valve 51 and the second valve 52, and close the third valve 53 and the fourth valve 54. The first molten salt pump 35 drives the molten salt from the first molten salt storage tank 33 through the molten salt flow path 311, so that the molten salt can absorb the heat of the steam flow path as it flows through the molten salt flow path 311. After absorbing the heat, the molten salt can enter the first heat exchanger 42, and the molten salt heats the thermochemical heat storage material 411, effectively storing the heat in the thermochemical heat storage system 40. The molten salt after heat exchange enters the second molten salt storage tank 34 for storage. The water vapor generated by the thermochemical heat storage reactor 41 enters the evaporation and condensation device 44 for condensation and storage. The evaporation and condensation device 44 can collect the water vapor generated by the decomposition of the thermochemical heat storage material 411 to meet the energy storage requirements. When the required power generation load of the thermal power generation system 10 is higher than the preset power generation, the thermal power unit energy storage system 100 enters the heat release stage. Open the third valve 53 and the fourth valve 54, and close the first valve 51 and the second valve 52. The water vapor released by the evaporation and condensation device 44 enters the thermochemical thermal storage reactor 41. The water vapor released by the evaporation and condensation device 44 can enter the thermochemical thermal storage reactor 41 and react with the thermochemical thermal storage material 411 to release heat. The second molten salt pump 36 drives the molten salt from the second molten salt storage tank 34 through the first heat exchanger 42. The thermochemical thermal storage material 411 can heat the molten salt in the first heat exchanger 42, thereby increasing the temperature of the molten salt. The molten salt with increased temperature flows through the first heat exchange channel 321 and can exchange heat with the water vapor in the second heat exchange channel, thereby increasing the heat of the water vapor in the first steam generation flow path 11. At the same time, the molten salt after heat exchange enters the first molten salt storage tank 33 for storage.

[0046] Therefore, by using molten salt thermal energy storage as the main energy storage carrier, and thermochemical thermal energy storage only being used to raise the molten salt temperature during the heat release phase, the advantages of molten salt thermal energy storage—low cost, fast response speed, and long lifespan—are combined with the advantages of thermochemical thermal energy storage in high-temperature heat release and flexible temperature control. This effectively reduces the investment cost and engineering complexity of the thermal power unit energy storage system 100. Furthermore, the temperature of heat storage and release can be controlled using the reaction balance principle, realizing the conversion between medium-temperature energy storage and high-temperature heat release, thus improving the flexibility of the thermal power unit energy storage system 100. Simultaneously, the thermal power unit energy storage system 100 can reduce power generation output by extracting steam from the thermal power generation system 100 during off-peak hours, and supply heat to the thermal power generation system 100 during peak hours to enhance peak capacity. This enables flexible adjustment of off-peak electricity absorption and peak electricity feedback, which is beneficial for improving the peak-shaving and frequency regulation capabilities of the thermal power generation system 100.

[0047] Since the molten salt-thermochemical coupling-based thermal power unit energy storage system 100 according to the embodiments of the present invention has the above-mentioned beneficial technical effects, the operation method of the molten salt-thermochemical coupling-based thermal power unit energy storage system 100 according to the embodiments of the present invention involves a thermochemical thermal storage reactor 41 containing a thermochemical thermal storage material 411, a first heat exchanger 42 located within the thermochemical thermal storage reactor 41 for heat exchange with the thermochemical thermal storage material 411, and a molten salt thermal storage system 30 including a second heat exchanger 31 and a steam generating heat exchanger assembly 32. The second heat exchanger 31 includes a molten salt flow path 311 and a steam flow path, with the steam flow path connected in series with the second steam generating flow path 12. The steam generator heat exchanger assembly 32 has a first heat exchange channel 321 and a second heat exchange channel that exchange heat with each other. The molten salt flow path 311, the first heat exchanger 42 and the first heat exchange channel 321 are connected in sequence. The second heat exchange channel is connected in series with the first steam generator flow path 11, which enables the thermal power unit energy storage system 100 to flexibly adjust the absorption of off-peak electricity and the feedback of peak electricity, improve the peak-shaving and frequency regulation capabilities and flexibility of the thermal power generation system 10, and at the same time have the advantages of low cost, fast response speed and long life of molten salt thermal storage, as well as the advantages of thermochemical thermal storage in high-temperature heat release and flexible temperature control, effectively reducing the investment cost and engineering complexity of the thermal power unit energy storage system 100.

[0048] In some embodiments of the present invention, the operating method further includes: When the thermal power unit energy storage system 100 enters the heat storage stage, the water vapor partial pressure control device 43 controls the water vapor partial pressure in the thermochemical heat storage reactor 41 to reduce the decomposition temperature of the thermochemical heat storage material 411 (e.g., Ca(OH)2) and effectively improve the heat storage rate. When the thermal power unit energy storage system 100 enters the heat release stage, the water vapor partial pressure control device 43 increases the water vapor partial pressure in the thermochemical heat storage reactor 41, which can increase the heat release temperature of the thermochemical heat storage material 411 (e.g., CaO), realize molten salt medium-temperature heat storage-high-temperature heat release, and effectively improve the flexible control of the heat release temperature.

[0049] Other configurations and operations of the molten salt-thermal chemical coupling-based thermal power unit energy storage system 100 according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0050] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0051] In the description of this specification, the references to terms such as "embodiment," "specific embodiment," and "example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0052] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An energy storage system for thermal power units based on molten salt-thermochemical coupling, characterized in that, include: A thermal power generation system, wherein the thermal power generation system has a first steam generation flow path and a second steam generation flow path; A coupled thermal storage system includes a molten salt thermal storage system and a thermochemical thermal storage system. The thermochemical thermal storage system includes a thermochemical thermal storage reactor and a first heat exchanger. The thermochemical thermal storage reactor contains thermochemical thermal storage material. The first heat exchanger is located inside the thermochemical thermal storage reactor to exchange heat with the thermochemical thermal storage material. The molten salt thermal storage system includes a second heat exchanger and a steam generating heat exchanger assembly. The second heat exchanger includes a molten salt flow path and a steam flow path. The steam flow path is connected in series with the second steam generating flow path. The steam generating heat exchanger assembly has a first heat exchange channel and a second heat exchange channel that exchange heat with each other. The molten salt flow path, the first heat exchanger, and the first heat exchange channel are connected in sequence. The second heat exchange channel is connected in series with the first steam generating flow path.

2. The thermal power unit energy storage system based on molten salt-thermochemical coupling according to claim 1, characterized in that, The first heat exchanger has a first inlet, a first outlet, a second inlet, and a second outlet, and the molten salt thermal storage system further includes: First molten salt storage tank, second molten salt storage tank, first molten salt pump, and second molten salt pump; The first molten salt flow path includes the first molten salt storage tank, the first molten salt pump, the molten salt flow path, the first inlet, the first heat exchanger, the first outlet, and the second molten salt storage tank connected in series on the first molten salt flow path. The first inlet and the first outlet are respectively equipped with a first valve and a second valve. The second molten salt flow path comprises the second molten salt storage tank, the second molten salt pump, the second inlet, the first heat exchanger, the second outlet, the first heat exchange channel, and the first molten salt storage tank connected in series on the second molten salt flow path. The second inlet and the second outlet are respectively equipped with a third valve and a fourth valve.

3. The thermal power unit energy storage system based on molten salt-thermochemical coupling according to claim 1, characterized in that, The first heat exchange channel includes a first sub-molten salt flow path, a second sub-molten salt flow path, and a third sub-molten salt flow path that are interconnected. The second heat exchange channel includes a first sub-steam flow path, a second steam flow path, and a third steam flow path that are interconnected. The steam generating heat exchanger assembly includes: The superheater, wherein the first sub-molten salt flow path and the first sub-steam flow path are located in the superheater; An evaporator, wherein the second sub-molten salt flow path and the second sub-vapor flow path are located in the evaporator; The preheater, wherein the third sub-molten salt flow path and the third sub-steam flow path are located in the preheater.

4. The thermal power unit energy storage system based on molten salt-thermochemical coupling according to claim 1, characterized in that, The thermal power unit energy storage system has a heat storage stage and a heat release stage, and the thermochemical heat storage system further includes: A water vapor partial pressure control device is used to regulate the water vapor partial pressure in the thermochemical thermal storage reactor. An evaporative condensation device is used to collect water vapor generated by the decomposition of the thermochemical thermal storage material during the thermal storage stage, or to provide water vapor to the thermochemical thermal storage material during the heat release stage.

5. The thermal power unit energy storage system based on molten salt-thermochemical coupling according to claim 1, characterized in that, The thermal power generation system includes: The boiler has a feedwater inlet and a main steam outlet, with one end of the first steam generating flow path connected to the feedwater inlet and the other end connected to the main steam outlet.

6. The thermal power unit energy storage system based on molten salt-thermochemical coupling according to claim 5, characterized in that, The thermal power generation system also includes: High-pressure cylinder, intermediate-pressure cylinder, low-pressure cylinder, condenser, and deaerator; A high-pressure heater assembly, comprising a first high-pressure heater, a second high-pressure heater, and a third high-pressure heater; A low-pressure heater assembly, comprising a fifth low-pressure heater, a sixth low-pressure heater, a seventh low-pressure heater, and an eighth low-pressure heater; The circulating water pump includes a condensate pump and a feedwater pump. The high-pressure cylinder, the intermediate-pressure cylinder, the low-pressure cylinder, the condenser, the condensate pump, the low-pressure heater group, the deaerator, the feedwater pump, the high-pressure heater group, and the boiler are connected.

7. The thermal power unit energy storage system based on molten salt-thermochemical coupling according to claim 6, characterized in that, The steam flow path has a third inlet and a third outlet. The third inlet and the first high-pressure heater are both connected to the extraction port of the high-pressure cylinder. The third outlet is connected to at least one of the inlet of the deaerator and an external heat user.

8. The thermal power unit energy storage system based on molten salt-thermochemical coupling according to claim 5, characterized in that, Also includes: The regulating valve includes a first port, a second port, and a third port. The first port is connected to an external heat user, the second port is connected to the main steam outlet, and the third port is connected to the first steam flow path. The third port can be selectively connected to at least one of the first port and the second port.

9. An operation method for an energy storage system of a thermal power unit based on molten salt-thermochemical coupling, characterized in that, The molten salt-thermochemical coupling-based thermal power unit energy storage system is the molten salt-thermochemical coupling-based thermal power unit energy storage system according to any one of claims 1-8, wherein the thermal power unit energy storage system has a heat storage stage and a heat release stage, and the operation method includes: When the required power generation load of the thermal power generation system is lower than the preset power generation, the thermal power unit energy storage system enters the thermal storage stage. Open the first and second valves, close the third and fourth valves, and the first molten salt pump drives the molten salt to flow from the first molten salt storage tank through the molten salt flow path and the first heat exchanger and into the second molten salt storage tank. The water vapor generated by the thermochemical thermal storage reactor enters the evaporation and condensation device for condensation and storage. When the required power generation load of the thermal power generation system is higher than the preset power generation, the energy storage system of the thermal power unit enters the heat release stage; Open the third and fourth valves, close the first and second valves, and the water vapor released by the evaporation and condensation device enters the thermochemical thermal storage reactor. The second molten salt pump drives the molten salt from the second molten salt tank through the first heat exchanger and the first heat exchange channel and into the first molten salt tank.

10. The operation method of the thermal power unit energy storage system based on molten salt-thermochemical coupling according to claim 9, characterized in that, The operating method further includes: When the thermal power unit energy storage system enters the thermal storage stage, the water vapor partial pressure control device is controlled to reduce the water vapor partial pressure in the thermochemical thermal storage reactor. When the thermal power unit's energy storage system enters the heat release stage, the water vapor partial pressure control device is controlled to increase the water vapor partial pressure in the thermochemical thermal storage reactor.

Images