A steam molten salt energy storage system for thermal power units
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-23
- Publication Date
- 2026-08-14
AI Technical Summary
但现有设计中不能合理充分利用能级，使得能量浪费；因此，本实用新型提供一种供热火电机组蒸汽熔盐储能系统
[0012]本方案通过设置第二换热器、第三换热器两级串联的储热换热器，实现了对抽汽能量的梯级利用，大幅降低了换热过程中的损失，提升了整个储能系统的热效率；
Smart Images
Figure CN224635874U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a steam molten salt energy storage system for thermal power units, belonging to the technical field of thermal power units. Background Technology
[0002] Molten salt thermal energy storage technology is an advanced thermal energy storage system. Its core principle is to store thermal energy in a high-temperature molten salt solution for subsequent conversion into electricity or heat. It features low theoretical cost, high operating temperature, high energy density, long lifespan, safety, and environmental friendliness.
[0003] When the unit's operating load rate needs to decrease, the energy generated during unit operation can be used to heat the molten salt, forming hot molten salt in the cold molten salt tank, which is then stored in the hot molten salt tank, thus reducing the unit's load rate. When the unit's operating load rate needs to increase, the molten salt in the hot molten salt tank can release heat to generate steam, which returns to the cold molten salt tank and then returns to the unit to perform work or supply heat to the outside, thus increasing the unit's load rate. However, existing designs cannot make reasonable and full use of energy levels, resulting in energy waste. Therefore, this utility model provides a steam molten salt energy storage system for heating thermal power units. Utility Model Content
[0004] To address the aforementioned problems in existing technologies, this utility model provides a steam molten salt energy storage system for thermal power units, which can improve energy utilization efficiency by rationally setting the number of heat exchange stages and configuring water intake and steam extraction ports.
[0005] The technical solution of this utility model is as follows:
[0006] A steam molten salt energy storage system for a thermal power unit includes a thermal power generating unit and a steam molten salt energy storage system. The thermal power generating unit is equipped with a reheat steam pipeline for providing medium-pressure heating steam and a medium-pressure cylinder exhaust pipeline for providing low-pressure heating steam. The steam molten salt energy storage system includes a cold molten salt tank, a hot molten salt tank, a first heat exchanger, a second heat exchanger, and a third heat exchanger. The No. 2 high-pressure heater drain outlet pipeline and the No. 5 low-pressure feedwater outlet pipeline of the thermal power generating unit each have branch outlet pipelines that merge into a main pipeline and are then connected to the water-side inlet of the first heat exchanger. The steam-side outlet of the first heat exchanger is connected to a medium-pressure heating pipeline for external heating. The outlet of the hot molten salt tank is connected to the molten salt-side inlet of the first heat exchanger via a pipeline equipped with a molten salt pump. The molten salt outlet of the first heat exchanger is connected to the inlet of the cold molten salt tank; the inlet of the hot molten salt tank is connected to the molten salt outlet of the second heat exchanger; the outlet of the cold molten salt tank is connected to the molten salt inlet of the third heat exchanger via a pipe equipped with a molten salt pump, and the molten salt outlet of the third heat exchanger is connected to the molten salt inlet of the second heat exchanger; a steam branch pipe is led out from the reheat steam pipe of the thermal power generating unit and connected to the steam inlet of the second heat exchanger; the steam outlet of the second heat exchanger is connected to the steam inlet of the third heat exchanger via a steam pipe, and this steam pipe is connected to the medium-pressure heating pipe via a bypass branch pipe; the steam outlet of the third heat exchanger is connected to a low-pressure heating pipe for external heating.
[0007] The outlet branch pipe and the main pipe are equipped with flow control valves, and the steam branch pipe is equipped with a flow control valve; the steam pipe is equipped with an electric regulating valve, the pressure before the regulating valve is higher than the pressure of the medium-pressure heating pipe, and the bypass branch pipe is equipped with an electric regulating valve and a gate valve.
[0008] The main pipe is also equipped with a gate valve; both the medium-pressure heating pipeline and the low-pressure heating pipeline are equipped with gate valves.
[0009] The second heat exchanger is a high-temperature heat storage heat exchanger, and is connected to medium-pressure steam from a reheat steam pipeline; the third heat exchanger is a low-temperature heat storage heat exchanger, and is connected to steam that has undergone heat exchange in the second heat exchanger.
[0010] The first heat exchanger is a heat-exhausting end heat exchanger, which uses hot molten salt to heat the feedwater to generate medium-pressure heating steam.
[0011] This utility model has the following beneficial effects:
[0012] This scheme achieves cascaded utilization of extracted steam energy by setting up a two-stage heat exchanger system with a second and a third heat exchanger connected in series, significantly reducing the heat exchange process costs. This reduces losses and improves the thermal efficiency of the entire energy storage system.
[0013] This solution adopts a high-pressure condensate drainage and low-pressure water supply method, and uses an electric regulating valve to precisely control the flow rate and ratio, which can flexibly match different heating demands and molten salt heat release conditions, ensuring the stability and economy of system operation.
[0014] This scheme sets up a bypass branch with a valve on the steam pipeline between the second and third heat exchangers to connect to the medium-pressure heating pipeline, which can directly supplement the steam supply to the heat users under specific operating conditions, and also serves as a safe and reliable regulation guarantee.
[0015] This solution effectively combines the flexible regulation of thermal power units with efficient energy storage, helping the power grid absorb intermittent renewable energy while ensuring the quality and reliability of external heating. It has high comprehensive energy utilization efficiency and significant economic and environmental benefits. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of a steam molten salt energy storage system for a thermal power unit according to the present invention.
[0017] The reference numerals in the figure are as follows:
[0018] 1. Cold molten salt tank; 2. Hot molten salt tank; 3. First heat exchanger; 4. Second heat exchanger; 5. Third heat exchanger; 6. No. 2 high-pressure heater drain outlet pipe; 7. No. 5 low-pressure water supply outlet pipe; 8. Main pipe; 81. Outlet branch pipe; 31. Medium-pressure heating pipe; 41. Steam branch pipe; 42. Steam pipe; 51. Low-pressure heating pipe. Detailed Implementation
[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.
[0020] Please see Figure 1 The utility model provides a technical solution:
[0021] like Figure 1As shown, the steam molten salt energy storage system for a thermal power unit in this embodiment includes a thermal power generating unit and a steam molten salt energy storage system. The thermal power generating unit is equipped with a reheat steam pipeline for providing medium-pressure heating steam and a medium-pressure cylinder exhaust pipeline for providing low-pressure heating steam. The steam molten salt energy storage system includes a cold molten salt tank 1, a hot molten salt tank 2, a first heat exchanger 3, a second heat exchanger 4, and a third heat exchanger 5. The No. 2 high-pressure heater drain outlet pipeline 6 and the No. 5 low-pressure feedwater outlet pipeline 7 of the thermal power generating unit respectively lead out outlet branch pipelines 81 and merge into a main pipeline 8, which is then connected to the water-side inlet of the first heat exchanger 3. The steam-side outlet of the first heat exchanger 3 is connected to a medium-pressure heating pipeline 31 for external heating. The outlet of the hot molten salt tank 2 is connected to the first heat exchanger through a pipeline equipped with a molten salt pump. The molten salt inlet of the first heat exchanger 3 and the molten salt outlet of the first heat exchanger 3 are connected to the inlet of the cold molten salt tank 1; the inlet of the hot molten salt tank 2 is connected to the molten salt outlet of the second heat exchanger 4; the outlet of the cold molten salt tank 1 is connected to the molten salt inlet of the third heat exchanger 5 through a pipe equipped with a molten salt pump, and the molten salt outlet of the third heat exchanger 5 is connected to the molten salt inlet of the second heat exchanger 4; the reheat steam pipeline of the thermal power generator set leads out a steam branch pipeline 41 and is connected to the steam inlet of the second heat exchanger 4; the steam outlet of the second heat exchanger 4 is connected to the steam inlet of the third heat exchanger 5 through a steam pipeline 42, and the steam pipeline 42 is connected to the medium-pressure heating pipeline 31 through a bypass branch pipeline; the steam outlet of the third heat exchanger 5 is connected to a low-pressure heating pipeline 51 for external heating.
[0022] Flow control valves are installed on the outlet branch pipe 81 and the main pipe 8, and flow control valves are installed on the steam branch pipe 41; electric regulating valves are installed on the steam pipe 42, and the pressure before the regulating valve is higher than the pressure of the medium-pressure heating pipe 31. Electric regulating valves and gate valves are installed on the bypass branch pipes.
[0023] Gate valves are also installed on the main pipe 8; gate valves are also installed on the medium-pressure heating pipeline 31 and the low-pressure heating pipeline 51.
[0024] The second heat exchanger 4 is a high-temperature heat storage heat exchanger, and the second heat exchanger 4 is connected to medium-pressure steam from the reheat steam pipeline; the third heat exchanger 5 is a low-temperature heat storage heat exchanger, and the steam after heat exchange in the second heat exchanger 4 is connected to it; the first heat exchanger 3 is a heat release end heat exchanger, and the first heat exchanger 3 uses hot molten salt to heat the feedwater to generate medium-pressure heating steam.
[0025] The heat exchanger at the thermal storage end, as referred to in this article, is a heat exchange device used in the energy storage process. Specifically, it includes the second heat exchanger 4 and the third heat exchanger 5. Its function is to utilize the thermal energy of medium-pressure steam delivered from the steam branch pipe 41, which is drawn from the reheat steam pipe of the thermal power generating unit, when the unit requires heat storage. Through the series arrangement of the second and third heat exchangers 4 and 5, the low-temperature molten salt pumped from the cold molten salt tank 1 to the third heat exchanger 5 is heated in stages and steps, ultimately storing the high-temperature molten salt in the hot molten salt tank 2, thus completing the process of heat storage. The process involves the storage of thermal energy converted into the internal energy of molten salt. The heat exchanger at the heat release end specifically refers to the first heat exchanger 3 used in the energy release process. Its function is to pump the high-temperature molten salt stored in the hot molten salt tank 2 to the first heat exchanger 3 when external heating or unit load needs to be supplied, so as to heat the feedwater that is taken from the No. 2 high-pressure heater drain outlet pipe 6 and the No. 5 low-pressure feedwater outlet pipe 7 and transported through the main pipe 8, so that it is converted into steam and output through the medium-pressure heating pipe 31, thereby realizing the process of converting the stored molten salt thermal energy back into usable steam thermal energy.
[0026] The workflow of this scheme is mainly divided into two core processes: heat storage and heat release. The efficient transfer and utilization of energy is achieved through the coordinated operation of three heat exchangers. During the heat storage process, when the load of the thermal power unit needs to be reduced, the system activates the heat storage mode: medium-pressure steam from the unit's reheat steam pipeline first enters the second heat exchanger 4, which serves as a high-temperature heat storage heat exchanger, through steam branch pipeline 41. Here, a large amount of high-temperature sensible heat is released to heat the pre-heated medium-temperature molten salt flowing from the third heat exchanger 5, further increasing its temperature before it is stored in the hot molten salt tank 2. The steam, after being cooled and depressurized by the second heat exchanger 4, then enters the third heat exchanger 5, which serves as a low-temperature heat storage heat exchanger, through steam pipeline 42. The residual heat is further used to heat the low-temperature molten salt pumped from the cold molten salt tank 1, completing the cascade heat exchange. The exhaust steam, after fully extracting steam energy, can then be supplied externally as needed. This process, through two-stage series heat exchange, achieves the recovery and utilization of high-grade steam energy, greatly improving the heat storage efficiency. During the heat release process, when the unit needs to increase load or supply heat to the outside, the system switches to heat release mode. That is, the high-temperature molten salt stored in the hot molten salt tank 2 is transported by the molten salt pump to the first heat exchanger 3, which serves as the heat release end heat exchanger, to exchange heat with the feedwater from the unit's feedwater system. The feedwater is drawn from two water intake points with different temperatures and pressures, namely the No. 2 high-pressure heater drain outlet pipe 6 and the No. 5 low-pressure feedwater outlet pipe 7. After being mixed and regulated by branch pipes, it enters the first heat exchanger 3 through the main pipe 8, where it is heated and evaporated by the high-temperature molten salt to generate medium-pressure steam with the required parameters. This steam is then stably supplied to the outside through the medium-pressure heating pipe 31. The molten salt that has cooled down after heat release flows back to the cold molten salt tank 1, completing one cycle.
[0027] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.
Claims
1. A steam molten salt energy storage system for a thermal power unit, comprising a thermal power generating unit and a steam molten salt energy storage system; wherein the thermal power generating unit is equipped with a reheat steam pipeline for providing medium-pressure heating steam and a medium-pressure cylinder exhaust pipeline for providing low-pressure heating steam, characterized in that: The steam molten salt energy storage system includes a cold molten salt tank (1), a hot molten salt tank (2), a first heat exchanger (3), a second heat exchanger (4), and a third heat exchanger (5); the No. 2 high-pressure heater drain outlet pipe (6) and the No. 5 low-pressure feedwater outlet pipe (7) of the thermal power generator set respectively lead out outlet branch pipes (81) and merge into a main pipe (8) and then connect to the water side inlet of the first heat exchanger (3); the steam side outlet of the first heat exchanger (3) is connected to a medium-pressure heating pipe (31) for external heating; the outlet of the hot molten salt tank (2) is connected to the molten salt side inlet of the first heat exchanger (3) through a pipe equipped with a molten salt pump, and the molten salt side outlet of the first heat exchanger (3) is connected to the inlet of the cold molten salt tank (1); the inlet of the hot molten salt tank (2) is connected to The molten salt side outlet of the second heat exchanger (4); the outlet of the cold molten salt tank (1) is connected to the molten salt side inlet of the third heat exchanger (5) through a pipe equipped with a molten salt pump, and the molten salt side outlet of the third heat exchanger (5) is connected to the molten salt side inlet of the second heat exchanger (4); the reheat steam pipeline of the thermal power generator set leads out a steam branch pipeline (41) connected to the steam side inlet of the second heat exchanger (4); the steam side outlet of the second heat exchanger (4) is connected to the steam side inlet of the third heat exchanger (5) through a steam pipeline (42), and the steam pipeline (42) is connected to the medium-pressure heating pipeline (31) through a bypass branch pipeline; the steam side outlet of the third heat exchanger (5) is connected to a low-pressure heating pipeline (51) for external heating.
2. A thermal power plant steam molten salt energy storage system of claim 1, wherein: The outlet branch pipe (81) and the main pipe (8) are equipped with flow control valves, and the steam branch pipe (41) is equipped with a flow control valve; the steam pipe (42) is equipped with an electric regulating valve, the pressure before the regulating valve is higher than the pressure of the medium-pressure heating pipe (31), and the bypass branch pipe is equipped with an electric regulating valve and a gate valve.
3. A thermal power plant steam molten salt energy storage system of claim 1, wherein: A gate valve is also installed on the main pipe (8); gate valves are installed on both the medium-pressure heating pipeline (31) and the low-pressure heating pipeline (51).
4. A thermal power plant steam molten salt energy storage system of claim 1, wherein: The second heat exchanger (4) is a high-temperature heat storage heat exchanger, and the second heat exchanger (4) is connected to medium-pressure steam from the reheat steam pipeline; the third heat exchanger (5) is a low-temperature heat storage heat exchanger, and is connected to the steam after heat exchange by the second heat exchanger (4).
5. A thermal power plant steam molten salt energy storage system of claim 1, wherein: The first heat exchanger (3) is a heat-dissipating end heat exchanger. The first heat exchanger (3) uses hot molten salt to heat the feed water to generate medium-pressure heating steam.