Thermal remelting salt heat storage system for thermal power plant
By using a heat remelting salt heat storage system in thermal power plants, heat re-steam is exchanged with low-temperature molten salt and stored high-temperature molten salt, the problem of insufficient flexibility in steam supply and heating units is solved, and the flexible utilization of heat is achieved and power grid load peak shaving.
Patent Information
- Application Number
- CN202420546279.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-20
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2034-03-20
AI Technical Summary
The operating flexibility of the steam supply and heating units of the existing thermal power plants is insufficient, and it is difficult to simultaneously adjust the steam turbine load and the industrial steam supply demand of external users, resulting in waste of heat energy.
The heat remelting salt heat storage system is adopted to exchange heat with the low-temperature molten salt through the steam molten salt heat exchanger, store high-temperature molten salt, and use high-temperature molten salt to exchange heat with the unit water supply to generate the second industrial steam supply. Flexible adjustment of operating load and meet external users' needs.
It improves the flexibility of thermal power plants, avoids waste of heat and electricity, and can effectively utilize stored heat when needed to meet the peak peak of the grid load.
Smart Images
Figure CN222230516U_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of peak load regulation and energy storage in thermal power plants, and in particular, relates to a thermal remelting salt heat storage system for thermal power plants. Background Art
[0002] During the low electricity consumption period, the steam supply units are severely limited in their load reduction capacity due to the influence of steam supply parameters. If there is a large-scale development of new energy, the electricity will be obviously abundant, and problems such as "abandoning wind" and "abandoning solar" will occur. In order to better develop and consume new energy, promote the "three-in-one" transformation of coal-fired power energy conservation and carbon reduction, flexibility transformation, and heating transformation, and transform coal-fired power from the main power source to a supporting and regulating power source.
[0003] The operating flexibility of steam and heat supply units in the prior art has the following technical problems: the prior art usually adjusts the operating load by extracting steam from the steam turbine, and directly provides the extracted steam as industrial steam to external users. However, this method cannot simultaneously meet the requirements of both the load regulation of the steam turbine and the regulation of the industrial steam demand by external users, which easily leads to waste of thermal energy and insufficient flexibility. Utility Model Content
[0004] The present application provides a thermal remelting salt heat storage system for a thermal power plant, comprising a main steam turbine, a boiler, a main steam pipeline and a main return pipeline, wherein the main steam turbine comprises a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder, wherein the boiler uses a main steam pipeline to provide high-temperature and high-pressure main steam to the high-pressure cylinder, and the main return pipeline is used to transport condensate from the low-pressure cylinder back to the boiler, wherein a reheater is provided on the boiler, wherein the inlet of the reheater is connected to the outlet of the high-pressure cylinder through a primary return pipeline, and the primary return pipeline is used to transport the primary return steam of the high-pressure cylinder to the reheater, and the outlet of the reheater is connected to the medium-pressure cylinder through a primary return steam pipeline, so as to transport the hot resteam heated by the reheater to the medium-pressure cylinder; the medium-pressure cylinder is connected to the low-pressure cylinder through a secondary return pipeline, so as to transport the secondary return steam output by the medium-pressure cylinder to the low-pressure cylinder, comprising:
[0005] The steam molten salt heat exchanger is used to extract a part of the hot re-steam and exchange the hot re-steam with the low-temperature molten salt flowing inside it to obtain the first industrial steam supply and high-temperature molten salt. The hot re-steam has a higher temperature than the first industrial steam supply.
[0006] Furthermore, the system also includes:
[0007] A low-temperature molten salt storage tank is connected to the molten salt inlet of the steam molten salt heat exchanger;
[0008] A high-temperature molten salt storage tank is connected to the molten salt outlet of the steam molten salt heat exchanger.
[0009] Furthermore, the system also includes:
[0010] A molten salt water steam heat exchanger is used to utilize the high-temperature molten salt in the high-temperature molten salt storage tank to exchange heat with the unit supply water to obtain low-temperature molten salt and the second industrial steam supply, and the low-temperature molten salt is stored in the low-temperature molten salt storage tank;
[0011] The unit water supply pipe is used to provide water supply to the unit.
[0012] Furthermore, the second industrial steam supply is used to provide to the main steam turbine and / or external users.
[0013] Furthermore, the first industrial steam supply is used to provide to external users.
[0014] Furthermore, a molten salt heater is provided between the molten salt outlet of the steam molten salt heat exchanger and the high-temperature molten salt storage tank.
[0015] Furthermore, a water supply valve is provided on the water supply pipe of the unit; and a second steam supply valve is provided at the steam outlet of the molten salt water steam heat exchanger.
[0016] Furthermore, the hot resteam inlet of the steam molten salt heat exchanger is provided with a reheater hot section steam extraction and supply valve.
[0017] Furthermore, the steam outlet of the steam molten salt heat exchanger is provided with a temperature and pressure reducer and a steam supply valve.
[0018] Furthermore, a low-temperature molten salt pump is provided at the outlet of the low-temperature molten salt storage tank;
[0019] A high-temperature molten salt pump is provided at the outlet of the high-temperature molten salt storage tank.
[0020] Furthermore, the system further comprises: a generator connected to the main steam turbine;
[0021] The main reflux pipeline is provided with a low-pressure heater, a deaerator and a high-pressure heater in sequence.
[0022] The above technical solution of the present application has at least the following beneficial technical effects:
[0023] The system of the present application extracts a portion of hot resteam to adjust the operating power of the intermediate pressure cylinder, exchanges heat with the low-temperature molten salt circulating inside the intermediate pressure cylinder, and obtains the first industrial steam supply and high-temperature molten salt. The heat of the hot resteam is stored in the form of high-temperature molten salt for standby use, so that the heat in the high-temperature molten salt can be reused when needed. Compared with the prior art of directly providing the main steam of the boiler or the hot resteam of the reheater to external users, it is more flexible and avoids waste of heat or electricity. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0025] Figure 1 It is a structural schematic diagram of a hot remelting salt heat storage system for a thermal power plant in one embodiment of the present application.
[0026] Figure 2 It is a schematic diagram of the structure of the heat storage and release part of the system in one embodiment of the present application.
[0027] Figure 3 It is a structural schematic diagram of a hot remelting salt heat storage system for a thermal power plant in another embodiment of the present application.
[0028] Figure 4 It is a schematic diagram of the structure of the heat storage and release part of the system in another embodiment of the present application.
[0029] in, Figures 1 to 3 The corresponding relationship between the reference numerals and component names in the figure is:
[0030] 1. Boiler; 2. Reheater; 3. High-pressure cylinder; 4. Medium-pressure cylinder; 5. Low-pressure cylinder; 6. Generator; 7. Low-pressure heater; 8. Deaerator; 9. High-pressure heater; 10. Reheater hot section extraction steam supply valve; 11. Steam molten salt heat exchanger; 12. Temperature and pressure reducer; 13. Steam supply valve one; 14. Low-temperature molten salt storage tank; 15. High-temperature molten salt storage tank; 16. Low-temperature molten salt pump; 17. High-temperature molten salt pump; 18. Feedwater valve; 19. Molten salt water steam heat exchanger; 20. Steam supply valve two; 21. Hot resteam; 22. First industrial steam supply; 23. Unit water supply pipe; 24. Second industrial steam supply; 25. Electric heater. DETAILED DESCRIPTION
[0031] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present application, many technical details are proposed in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can also be implemented. The division of the following embodiments is for the convenience of description, and the specific implementation of the present application should not be construed as any limitation, and the various embodiments can be combined with each other and quoted from each other without contradiction.
[0032] At present, the existing technology uses the method of extracting steam from the steam turbine to adjust the operating load, and the extracted steam is directly provided to external users as industrial steam supply. However, this method cannot simultaneously meet the problems of steam turbine load regulation and external users' regulation of industrial steam supply demand.
[0033] To solve the above problems, Figure 1 The embodiment of the present application shown in the figure provides a thermal remelting salt heat storage system for a thermal power plant. The power generation system of a traditional thermal power plant mainly includes a main steam turbine, a boiler 1, a main steam pipeline and a main return pipeline; wherein the main steam turbine is provided with a high-pressure cylinder 3, a medium-pressure cylinder 4 and a low-pressure cylinder 5 connected in sequence, which together provide power for a generator 6; the boiler 1 uses the main steam pipeline to provide high-temperature and high-pressure main steam to the high-pressure cylinder 3, and the main return pipeline is used to transport the condensed water condensed in the low-pressure cylinder 5 back to the boiler 1, so that the steam can be transported between the boiler and the main steam turbine. The boiler 1 is also provided with a reheater 2, the inlet of the reheater 2 is connected with the outlet of the high-pressure cylinder 3 through a primary return pipe, the primary return pipe is used to transport the primary return steam of the high-pressure cylinder 3 to the reheater 2, and the outlet of the reheater 2 is connected with the intermediate-pressure cylinder 4 through a primary return steam pipe, which is used to transport the hot resteam 21 heated by the reheater 2 to the intermediate-pressure cylinder 4; the intermediate-pressure cylinder 4 is connected with the low-pressure cylinder 5 through a secondary return pipe, which is used to transport the secondary return steam output by the intermediate-pressure cylinder 4 to the low-pressure cylinder 5.
[0034] The main steam produced by the boiler 1 is extracted to adjust the overall operating power of the main turbine, or the first-stage reflux steam output by the high-pressure cylinder 3 is extracted to adjust the operating power of the high-pressure cylinder 3, or the hot re-steam 21 heated by the reheater 2 is extracted to adjust the operating power of the medium-pressure cylinder 4, and the extracted steam is provided to external users. The system in the present application is also provided with a steam molten salt heat exchanger 11. When the power demand is low or the power generation system needs to operate at a low load, a part of the hot re-steam 21 is extracted to adjust the operating power of the medium-pressure cylinder 4. The steam molten salt heat exchanger 11 exchanges heat with the low-temperature molten salt flowing inside it to obtain the first industrial steam supply 22 and high-temperature molten salt. The temperature of the hot re-steam 21 is higher than the temperature of the first industrial steam supply 22. The heat of the hot re-steam 21 is stored in the form of high-temperature molten salt for standby use, so as to reuse the heat in the high-temperature molten salt when needed. Compared with the existing method of directly providing the main steam of the boiler 1 or the hot re-steam 21 of the reheater 2 to external users, it is more flexible and avoids waste of heat or electricity.
[0035] Furthermore, the system also includes a low-temperature molten salt storage tank 14 and a high-temperature molten salt storage tank 15. The low-temperature molten salt storage tank 14 stores low-temperature molten salt and is connected to the molten salt inlet of the steam molten salt heat exchanger 11; the high-temperature molten salt storage tank 15 is connected to the molten salt outlet of the steam molten salt heat exchanger 11 to store the high-temperature molten salt obtained by heat exchange for standby use.
[0036] In one embodiment of the present application, Figure 2 As shown in the structural diagram of the heat storage and release part of the system, the system also includes a molten salt water vapor heat exchanger 19, which is respectively connected to the high-temperature molten salt storage tank 15 and the low-temperature molten salt storage tank 14, and is used to utilize the high-temperature molten salt in the high-temperature molten salt storage tank 15 to exchange heat with the unit water supply to obtain low-temperature molten salt and the second industrial steam supply 24, and the low-temperature molten salt is stored in the low-temperature molten salt storage tank 14; the unit water supply pipe 23 can supply water to the boiler 1, and can also provide unit water supply to the molten salt water vapor heat exchanger 19.
[0037] Furthermore, the second industrial steam supply 24 is used to provide the main steam turbine and / or external users. The first industrial steam supply 22 is used to provide external users. A water supply valve 18 is provided on the unit water supply pipe 23 to adjust the water supply amount; a steam supply valve 20 is provided at the steam outlet of the molten salt water steam heat exchanger 19 to adjust the amount of the output second industrial steam supply 24.
[0038] In this embodiment, when the power grid needs high load or full load peak regulation, the unit water supply pipe 23 provides part of the unit water supply to the molten salt water vapor heat exchanger 19 (including preheater, evaporator, superheater), and the unit water supply absorbs the heat in the high temperature molten salt from the high temperature molten salt storage tank 15 to generate the second industrial steam supply 24, which meets the requirements of industrial steam supply parameters and replaces part or all of the unit steam extraction, so that the unit meets the high load or full load power grid requirements. The high temperature molten salt pump 17 transports the high temperature molten salt from the high temperature molten salt storage tank 15 to the molten salt water vapor heat exchanger 19 to release heat, and the low temperature molten salt obtained after heat release enters the low temperature molten salt storage tank 14.
[0039] In one embodiment of the present application, Figure 3 and Figure 4 As shown, an electric heater 25 is provided between the molten salt outlet of the steam molten salt heat exchanger 11 and the high-temperature molten salt storage tank 15. In order to reasonably utilize the storage space of the high-temperature molten salt storage tank 15, the high-temperature molten salt is usually made to have a higher heat-to-mass ratio, that is, the high-temperature molten salt with a higher temperature can reduce the use of molten salt and thus save space and transmission costs. Therefore, the electric heater 25 is used to heat the high-temperature molten salt before it enters the high-temperature molten salt storage tank 15. The electric heater 25 utilizes the electricity produced by the power system where it is located, especially when the power grid demand is low load, to reduce the waste of electricity, further participate in the peak load regulation of the thermal power plant, and at the same time improve the frequency regulation capability of the unit.
[0040] Furthermore, a reheater hot section steam extraction and supply valve 10 is provided at the inlet of the hot resteam 21 of the steam molten salt heat exchanger 11 for controlling the amount of the extracted hot resteam 21 .
[0041] Furthermore, the steam outlet of the steam molten salt heat exchanger 11 is provided with a temperature reducer 12 and a steam supply valve 13. In order to ensure the heat exchange efficiency between the molten salt and the steam, the steam obtained by heat exchange with the low-temperature molten salt is still at a relatively high temperature and high pressure, and needs to be cooled and reduced in pressure before it can be provided to ordinary heat users among external users.
[0042] Furthermore, the system also includes: a generator 6 connected to the main steam turbine, the main steam turbine provides power for the generator 6; a low-pressure heater 7, a deaerator 8 and a high-pressure heater 9 are provided on the main return pipe from the main steam turbine to the downstream in sequence; the low-pressure heater 7 and the high-pressure heater 9 are used to preheat the condensate entering the boiler 1 and provide appropriate pressure.
[0043] In a specific implementation of the present application, when the power grid requires the unit (including the main steam turbine) to reduce the load for peak load regulation, when the unit load drops to 50% or lower, the existing steam supply parameters cannot meet the requirements. By increasing the extraction point of the hot section of the reheater 2, a part of the high-temperature steam is obviously stored in the molten salt. Heat storage, extract part of the hot re-steam 21 through the steam molten salt heat exchanger 11, release part of the sensible heat of the hot re-steam 21, and make fine adjustments through the temperature reduction and pressure reduction device 12 according to the requirements of industrial steam parameters to meet the needs of external users for industrial steam supply and increase the flexibility of steam supply; the low-temperature molten salt pump 16 transports the molten salt in the low-temperature molten salt storage tank 14 to the steam molten salt heat exchanger 11 to absorb heat, and the molten salt with a higher temperature after heat exchange enters the high-temperature molten salt storage tank 15 for standby.
[0044] When the power grid requires the unit to operate at high load or full load, the unit water supply pipe 23 is used to allow part of the unit's feed water to pass through the molten salt water vapor heat exchanger 19 (including preheater, evaporator, superheater) to absorb the heat in the high-temperature molten salt from the high-temperature molten salt storage tank 15, generate steam, meet the requirements of industrial steam supply parameters, replace part or all of the unit's steam extraction, and enable the unit to meet the high-load or full-load power grid requirements. The high-temperature molten salt pump 17 transports the molten salt from the high-temperature molten salt storage tank 15 to the molten salt water vapor heat exchanger 19 to release heat, and the molten salt after heat release enters the low-temperature molten salt storage tank 14.
[0045] In this embodiment, the system is adjusted at any time according to the steam volume required by the main steam turbine and the steam supply required by external users, and the two can be adjusted separately according to the two demands without conflict, thus avoiding waste of heat or electricity.
[0046] It should be understood that the above specific embodiments of the present application are only used to illustrate or explain the principles of the present application, and do not constitute a limitation to the present application. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present application should be included in the protection scope of the present application. In addition, the claims attached to the present application are intended to cover all changes and modifications that fall within the scope and boundaries of the attached claims, or the equivalent forms of such scope and boundaries.
Claims
1. A thermal remelting salt heat storage system for a thermal power plant, comprising a main steam turbine, a boiler (1), a main steam pipeline and a main return pipeline, wherein the main steam turbine has a high-pressure cylinder (3), a medium-pressure cylinder (4) and a low-pressure cylinder (5), the boiler (1) uses the main steam pipeline to provide high-temperature and high-pressure main steam to the high-pressure cylinder (3), and the main return pipeline is used to transport condensate from the low-pressure cylinder (5) back to the boiler (1), characterized in that: include: The boiler (1) is provided with a reheater (2), the inlet of the reheater (2) is connected to the outlet of the high-pressure cylinder (3) through a primary return pipe, the primary return pipe is used to transport the primary return steam of the high-pressure cylinder (3) to the reheater (2), the outlet of the reheater (2) is connected to the medium-pressure cylinder (4) through a primary return steam pipe, and is used to transport the hot resteam (21) heated by the reheater (2) to the medium-pressure cylinder (4); the medium-pressure cylinder (4) is connected to the low-pressure cylinder (5) through a secondary return pipe, and is used to transport the secondary return steam output by the medium-pressure cylinder (4) to the low-pressure cylinder (5); The steam molten salt heat exchanger (11) is used to extract a portion of hot resteam (21) and exchange heat between the hot resteam (21) and the low-temperature molten salt flowing inside it to obtain a first industrial steam supply (22) and high-temperature molten salt, wherein the hot resteam (21) has a higher temperature than the first industrial steam supply (22).
2. The thermal remelting salt heat storage system for a thermal power plant according to claim 1, characterized in that: Also includes: A low-temperature molten salt storage tank (14) is connected to the molten salt inlet of the steam molten salt heat exchanger (11); A high-temperature molten salt storage tank (15) is connected to the molten salt outlet of the steam molten salt heat exchanger (11).
3. The thermal remelting salt heat storage system for a thermal power plant according to claim 2, characterized in that: Also includes: a molten salt steam heat exchanger (19), used for utilizing the high-temperature molten salt in the high-temperature molten salt storage tank (15) to exchange heat with the unit supply water to obtain low-temperature molten salt and a second industrial steam supply (24), wherein the low-temperature molten salt is stored in the low-temperature molten salt storage tank (14); The unit water supply pipe (23) is used to provide water supply to the unit.
4. The thermal remelting salt heat storage system for a thermal power plant according to claim 3, characterized in that: The second industrial steam supply (24) is used to provide the main steam turbine and / or external users.
5. The thermal remelting salt heat storage system for a thermal power plant according to claim 3, characterized in that: The first industrial steam supply (22) is used to provide steam to external users.
6. The thermal remelting salt heat storage system for a thermal power plant according to claim 2, characterized in that: An electric heater (25) is provided between the molten salt outlet of the steam molten salt heat exchanger (11) and the high-temperature molten salt storage tank (15).
7. The thermal remelting salt heat storage system for a thermal power plant according to claim 3, characterized in that: The water supply pipe (23) of the unit is provided with a water supply valve (18); The steam outlet of the molten salt water steam heat exchanger (19) is provided with a second steam supply valve (20); The hot resteam (21) inlet of the steam molten salt heat exchanger (11) is provided with a reheater hot section steam extraction and supply valve (10).
8. The thermal remelting salt heat storage system for a thermal power plant according to claim 3, characterized in that: The steam outlet of the steam molten salt heat exchanger (11) is provided with a temperature and pressure reducer (12) and a steam supply valve (13).
9. The thermal remelting salt heat storage system for a thermal power plant according to claim 3, characterized in that: The outlet of the low-temperature molten salt storage tank (14) is provided with a low-temperature molten salt pump (16); A high-temperature molten salt pump (17) is provided at the outlet of the high-temperature molten salt storage tank (15).
10. The thermal remelting salt heat storage system for a thermal power plant according to claim 3, characterized in that: Also includes: a generator (6) connected to the main steam turbine; The main reflux pipeline is provided with a low-pressure heater (7), a deaerator (8) and a high-pressure heater (9) in sequence.