Heat storage method of fused salt coupling steam energy accumulator full-energy heat storage technology

Abstract

The invention provides a heat storage method of a fused salt coupling steam energy accumulator full-energy heat storage technology, and belongs to the technical field of steam energy storage and energy storage flexibility. Based on a heat storage system, the heat storage system comprises a fused salt heat storage system, a steam energy accumulator heat storage system and a heat storage control system; the heat storage control system comprises a steam supply pipeline, a first adjusting valve group, a second adjusting valve group and a third adjusting valve group, in the heat storage method, when the steam energy accumulator stores heat to be full before the high-temperature molten salt tank, the second adjusting valve group is opened, and steam flowing out of the heat storage medium passage is used for industrial steam supply; when the high-temperature molten salt tank is filled with heat before the steam energy accumulator, the third regulating valve group is opened to supply a cold medium to the desuperheater to cool the steam which is about to enter the steam energy accumulator; high-grade sensible heat, low-grade sensible heat and all latent heat of steam heat energy can be fully utilized, the energy utilization rate is increased, regulation and control of the heat storage system are more flexible, and meanwhile economic benefits are increased.

Description

Technical Field

[0001] This invention relates to the field of steam energy storage and energy storage flexibility technology, and in particular to a thermal storage method for a molten salt coupled steam accumulator full-energy thermal storage technology. Background Technology

[0002] In today's energy sector, with the rapid development of renewable energy and the diversification of energy supply and demand, the flexibility and stability of energy systems have become crucial considerations. On the one hand, energy demand varies significantly across different periods and seasons. Traditional steam-powered cycle systems often struggle to flexibly adjust the relationship between heat and electricity when responding to changes in energy supply and demand, limiting their efficient operation in complex energy environments. On the other hand, the intermittency and instability of renewable energy sources also pose significant challenges to energy supply.

[0003] Energy storage has attracted much attention as a key technology for improving the flexibility of steam power cycles. To achieve effective control of the steam energy storage process and improve energy utilization efficiency and system flexibility, rational and efficient thermal storage technologies have gradually become the research focus in the current energy storage field. Existing energy storage technologies are typically based on steam accumulators and molten salt thermal storage systems. However, current energy storage technologies still have certain problems. On the one hand, traditional steam accumulator technology mainly relies on the sensible and latent heat of water for energy storage. Although its structure is simple, its energy storage density is low, and the speed and range of energy storage process regulation are quite limited. On the other hand, although molten salt thermal storage systems have the advantages of high energy storage density and high operating temperature, their systems are complex, have high initial investment, and are always at risk of freezing due to the high freezing point of molten salt, resulting in inconvenient system start-up and shutdown and slow thermal response, putting them at a disadvantage in scenarios requiring rapid and flexible peak shaving. Existing energy storage pathways are often independent and fail to coordinate effectively, making it difficult for the system to simultaneously achieve the triple goals of high energy storage density, stable high-grade energy output, and rapid and flexible response.

[0004] Therefore, it is urgent to find ways to effectively solve the problems of low thermal storage efficiency and difficulty in flexible regulation during steam energy storage through innovative control strategies and advanced technologies, so as to achieve efficient control of the thermal storage process. Summary of the Invention

[0005] The purpose of this invention is to provide a thermal storage method for molten salt coupled steam accumulator full-energy thermal storage technology to solve the problems existing in the prior art. It can make full use of the high-grade sensible heat, low-grade sensible heat and all latent heat of steam thermal energy to improve energy utilization efficiency, and also make the control of the thermal storage system more flexible, while improving economic benefits.

[0006] To achieve the above objectives, the present invention provides the following solution: A thermal storage method based on molten salt coupled steam accumulator full-energy thermal storage technology is implemented in a thermal storage system based on molten salt coupled steam accumulator full-energy thermal storage technology. The thermal storage system includes: a molten salt thermal storage system, a steam accumulator thermal storage system, and a thermal storage control system. The molten salt thermal storage system includes a low-temperature molten salt tank, a high-temperature molten salt tank, and a thermal storage heat exchanger. The thermal storage heat exchanger has a thermal storage medium passage and a heating medium passage. The low-temperature molten salt tank and the high-temperature molten salt tank are respectively connected to the medium inlet and medium outlet of the thermal storage medium passage. The steam accumulator thermal storage system includes a steam accumulator, and the steam inlet of the steam accumulator is connected to the medium outlet of the heating medium passage. The thermal energy storage control system includes a steam supply pipeline, a first regulating valve group, a second regulating valve group, and a third regulating valve group. The steam supply pipeline includes a front steam path and a rear steam path. The front steam path connects to a steam source and the medium inlet of the heating medium passage. The rear steam path connects to the medium outlet of the heating medium passage and the steam inlet of the steam accumulator. A desuperheating and pressure reducing device is installed on the front steam path. The desuperheating and pressure reducing device is connected to a cold medium source through the first regulating valve group. The steam inlet of the second regulating valve group is connected to the rear steam path, and the connection point is located between the thermal energy storage heat exchanger and the steam accumulator. The steam outlet of the second regulating valve group is connected to industrial steam supply equipment. A desuperheater is also installed in the downstream steam circuit. The desuperheater is located between the steam inlet of the second regulating valve group and the steam accumulator. The desuperheater is connected to a cold medium source through the third regulating valve group. The cold medium source is used to cool the steam passing through the desuperheater. The heat storage method includes the following steps: Steam is supplied through the steam supply pipeline. The second and third regulating valve groups are closed, and the first regulating valve group is opened to supply a cooling medium to the desuperheater and pressure reducer. The desuperheated and pressure-reduced steam enters the heating medium passage. The low-temperature molten salt in the low-temperature molten salt tank enters the heat storage medium passage. After heat exchange between the low-temperature molten salt and steam, the temperature of the low-temperature molten salt rises and it enters the high-temperature molten salt tank. The low-temperature steam enters the steam accumulator for energy storage. When the steam accumulator fills up with heat before the high-temperature molten salt tank, the second regulating valve group opens, and the steam flowing out of the heat storage medium passage is used for industrial steam supply or sent back to the unit's thermal system via the second regulating valve group. When the high-temperature molten salt tank fills up with heat before the steam accumulator, the molten salt pump stops working, the third regulating valve group opens, and supplies a cooling medium to the desuperheater to cool the steam that is about to enter the steam accumulator.

[0007] As one embodiment, a molten salt pump for providing power for the flow of molten salt is provided between the low-temperature molten salt tank and the heating medium passage, and the molten salt pump can adjust the molten salt flow rate.

[0008] As one embodiment, the high-temperature molten salt tank is equipped with a liquid level sensor for measuring the height of the high-temperature molten salt liquid level. When the liquid level sensor detects that the liquid level of the high-temperature molten salt has reached the designed full liquid level, the molten salt pump is turned off and the third regulating valve group is turned on.

[0009] As one implementation, along the steam supply direction, a first shut-off valve, a hydraulic quick-closing valve, and a flow meter are sequentially arranged between the steam source and the desuperheater / pressure reducer.

[0010] As one embodiment, the first regulating valve group includes a second shut-off valve, a first regulating valve, and a third shut-off valve arranged sequentially along the cold medium supply direction.

[0011] In one embodiment, the second regulating valve group includes a fifth shut-off valve, a second regulating valve, and a fourth shut-off valve arranged sequentially along the steam supply direction.

[0012] As one embodiment, the third regulating valve group includes a sixth shut-off valve, a third regulating valve, and a seventh shut-off valve arranged sequentially along the cold medium supply direction.

[0013] As one embodiment, an eighth shut-off valve is provided at the steam inlet of the steam accumulator, and a check valve is provided in front of the eighth shut-off valve along the steam supply direction.

[0014] As one embodiment, the steam accumulator is equipped with a pressure sensor for measuring its internal pressure. When the pressure sensor measures that the internal pressure of the steam accumulator reaches the designed full-storage pressure value, the eighth shut-off valve is closed and the second regulating valve group is opened.

[0015] In one embodiment, the steam accumulator is connected to a water supply source via a water supply pump.

[0016] The present invention has the following technical advantages over the prior art: This invention discloses a thermal storage method for molten salt coupled steam accumulators, which fully utilizes the high-grade sensible heat, low-grade sensible heat, and all latent heat of steam energy, thereby improving energy efficiency. If the steam accumulator is fully charged before the high-temperature molten salt tank, the eighth shut-off valve is closed, cutting off the heating medium path from the steam accumulator thermal storage system. The steam that has exchanged heat with the molten salt in the thermal storage heat exchanger can be used for industrial steam supply through the second regulating valve group. During this process, the power of the molten salt pump can be adjusted, thereby regulating the outlet flow rate of the low-temperature molten salt tank and flexibly controlling the outlet steam parameters of the heating medium of the thermal storage heat exchanger to achieve industrial steam supply with different parameters. This strategy significantly improves the system's operational flexibility and energy utilization efficiency, avoids redundancy and heat loss in energy storage after the steam accumulator is fully loaded, realizes a highly efficient "on-demand" energy supply mode, and enhances economic benefits and market competitiveness. Meanwhile, its rapid response capability enhances the system's adaptability to industrial heat load fluctuations, supports priority in ensuring production energy consumption in power-heat coordinated scheduling, and embodies the advanced thermal system control concept of demand-oriented, efficient matching, and dynamic regulation.

[0017] If the high-temperature molten salt tank fills up before the steam accumulator, the molten salt pump is shut down, and the heat storage heat exchanger stops working. The steam passing through the heat storage heat exchanger continues to flow through the desuperheater, and the desuperheated steam continues to be stored in the steam accumulator. During this process, the opening of the third regulating valve in the third regulating valve group can be adjusted to control the flow rate of the cold medium and adjust the steam inlet parameters of the steam accumulator, thereby achieving flexible control of the heat storage rate of the steam accumulator. This mechanism not only ensures the continuous and safe operation of the system under molten salt heat storage saturation conditions, avoiding the risk of overheating and overpressure caused by heat accumulation, but also improves the heat storage efficiency and equipment life of the steam accumulator by optimizing the steam inlet parameters. In addition, the adjustability of the heat storage rate supports the system to implement a phased energy storage strategy according to demand or subsequent energy consumption plans, enhancing the system's adaptability and economy in multi-timescale energy management. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the thermal storage system structure of the molten salt coupled steam accumulator full-energy thermal storage technology in one embodiment of the present invention; Explanation of reference numerals in the attached figures: 1. Steam supply pipeline; 2. First shut-off valve; 3. Hydraulic quick-closing valve; 4. Flow meter; 5. Desuperheater and pressure reducer; 6. Second shut-off valve; 7. First regulating valve; 8. Third shut-off valve; 9. Safety valve; 10. Thermal storage heat exchanger; 11. Fourth shut-off valve; 12. Second regulating valve; 13. Fifth shut-off valve; 14. Sixth shut-off valve; 15. Third regulating valve; 16. Seventh shut-off valve; 17. Desuperheater; 18. High-temperature molten salt tank; 19. Molten salt pump; 20. Low-temperature molten salt tank; 21. Check valve; 22. Eighth shut-off valve; 23. Steam accumulator; 24. Makeup water pump; 25. First regulating valve group; 26. Second regulating valve group; 27. Third regulating valve group; 28. Molten salt thermal storage system; 29. ​​Steam accumulator thermal storage system; 30. Thermal storage control system. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The purpose of this invention is to provide a thermal storage method for molten salt coupled steam accumulator full-energy thermal storage technology to solve the problems existing in the prior art. It can make full use of the high-grade sensible heat, low-grade sensible heat and all latent heat of steam thermal energy to improve energy utilization efficiency, and also make the control of the thermal storage system more flexible, while improving economic benefits.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1As shown, this invention provides a thermal storage method based on molten salt coupled steam accumulator full-energy thermal storage technology. This method is implemented using a thermal storage system based on molten salt coupled steam accumulator full-energy thermal storage technology. The thermal storage system includes a molten salt thermal storage system 28, a steam accumulator thermal storage system 29, and a thermal storage control system 30. The molten salt thermal storage system 28 includes a low-temperature molten salt tank 20, a high-temperature molten salt tank 18, and a thermal storage heat exchanger 10. The thermal storage heat exchanger 10 has a thermal storage medium passage and a heating medium passage. Salt tank 20 and high-temperature molten salt tank 18 are respectively connected to the medium inlet and medium outlet of the heat storage medium passage; the steam accumulator heat storage system 29 includes a steam accumulator 23, the steam inlet of which is connected to the medium outlet of the heat supply medium passage; the heat storage control system 30 includes a steam supply pipeline 1, a first regulating valve group 25, a second regulating valve group 26, and a third regulating valve group 27. The steam supply pipeline 1 includes a front steam path and a rear steam path. The front steam path connects to the steam source and the heat supply medium passage. The medium inlet is connected to the medium outlet of the heating medium passage and the steam inlet of the steam accumulator 23 in the front section of the steam path; a desuperheating and pressure reducing device 5 is installed in the front section of the steam path, which is connected to a cold medium source through the first regulating valve group 25. The cold medium source is used to desuperheat and reduce the pressure of the steam passing through the desuperheating and pressure reducing device 5; the steam inlet of the second regulating valve group 26 is connected to the rear section of the steam path, and the connection position is located between the heat storage heat exchanger 10 and the steam accumulator 23. The steam outlet of the second regulating valve group 26 is connected to the industrial power supply. In the steam equipment, when the steam accumulator 23 fills up with heat before the high-temperature molten salt tank 18, the second regulating valve group 26 opens; a desuperheater 17 is also installed in the downstream steam line. The desuperheater 17 is located between the steam inlet end of the second regulating valve group 26 and the steam accumulator 23. The desuperheater 17 is connected to the cold medium source through the third regulating valve group 27. The cold medium source is used to cool the steam passing through the desuperheater 17. When the high-temperature molten salt tank 18 fills up with heat before the steam accumulator 23, the third regulating valve group 27 opens.

[0024] In the implementation of the heat storage method of this invention, the first regulating valve group 25, the second regulating valve group 26, and the third regulating valve group 27 are in the closed state. Steam is drawn from the steam power cycle unit and introduced into the steam supply pipeline 1, which then flows into the heating medium passage of the heat storage heat exchanger 10. The first regulating valve group 25 is selectively opened according to the steam temperature. The cold medium flows through the first regulating valve group 25 into the desuperheating and pressure reducing device 5 to desuperheat and reduce the pressure of the steam. The cold medium in this invention is cold water, which acts on the desuperheating and pressure reducing device 5 by spraying, reducing the temperature of the steam inside the desuperheating and pressure reducing device 5. By controlling the amount of sprayed cold water, the steam about to enter the heating medium passage is maintained within a certain temperature range, reducing the loss to the heat storage heat exchanger 10 and ensuring that the heat storage heat exchanger 10 operates under stable and safe conditions. The low-temperature molten salt in the low-temperature molten salt tank 20 flows into the heat storage medium passage; the low-temperature molten salt exchanges heat with the steam in the heat storage heat exchanger 10. After the temperature of the low-temperature molten salt rises, it flows into the high-temperature molten salt tank 18 to store the thermal energy. To enhance the heat exchange efficiency between molten salt and steam, the flow direction of the molten salt is opposite to that of the steam. After one heat exchange, the steam enters the steam accumulator 23, which stores the low-grade sensible heat and all latent heat in the medium- and low-temperature range of the steam.

[0025] The thermal storage method in this invention can fully utilize the high-grade sensible heat, low-grade sensible heat, and all latent heat of steam thermal energy, thereby improving energy utilization efficiency. If the steam accumulator 23 is fully charged before the high-temperature molten salt tank 18, the heating medium passage and the steam accumulator thermal storage system 29 are cut off. The steam that has exchanged heat with the molten salt through the thermal storage heat exchanger 10 can be used for industrial steam supply through the second regulating valve group 26. This strategy significantly improves the system's operational flexibility and energy utilization efficiency, avoids redundancy and heat loss in energy storage after the steam accumulator 23 is fully loaded, realizes a highly efficient "on-demand" energy supply mode, and enhances economic benefits and market competitiveness. At the same time, its rapid response capability enhances the system's adaptability to industrial heat load fluctuations, supports priority in ensuring production energy consumption in power-heat coordinated scheduling, and embodies the advanced thermal system control concept of demand-oriented, efficient matching, and dynamic regulation.

[0026] If the high-temperature molten salt tank 18 fills before the steam accumulator 23, the molten salt pump 19 is shut down, and the heat storage heat exchanger 10 stops operating. The steam passing through the heat storage heat exchanger 10 continues to flow through the desuperheater 17, and the desuperheated steam continues to be stored in the steam accumulator 23. This mechanism not only ensures the continuous and safe operation of the system under molten salt heat storage saturation conditions, avoiding the risk of overheating and overpressure caused by heat accumulation, but also improves the heat storage efficiency and equipment lifespan of the steam accumulator 23 by optimizing the steam inlet parameters. In addition, the adjustability of the heat storage rate allows the system to implement a phased energy storage strategy according to demand or subsequent energy consumption plans, enhancing the system's adaptability and economy in multi-timescale energy management.

[0027] In this invention, a molten salt pump 19 is installed between the low-temperature molten salt tank 20 and the heating medium passage to provide power for the flow of molten salt. A level sensor is installed in the high-temperature molten salt tank 18 to measure the height of the high-temperature molten salt liquid. When the level sensor detects that the high-temperature molten salt level has reached the designed full level (which can be 90%~95% of the upper limit), it indicates that the heat in the high-temperature molten salt tank 18 has been fully stored. At this time, the molten salt pump 19 needs to be shut down and the third regulating valve group 27 opened. When the liquid level in the high-temperature molten salt tank 18 has not reached 100% of the upper limit, the molten salt pump 19 is shut down and the third regulating valve group 27 is opened (the third regulating valve group 27 can be opened slightly earlier than the molten salt pump 19), which can, to some extent, compensate for the delay in steam temperature regulation after the third regulating valve group 27 is opened.

[0028] If the steam accumulator 23 is filled with heat before the high-temperature molten salt tank 18, the power of the molten salt pump 19 can be adjusted, thereby adjusting the outlet flow of the low-temperature molten salt tank 20, and flexibly controlling the outlet steam parameters of the heat storage heat exchanger 10 to achieve industrial steam supply with different parameters.

[0029] This invention, by installing a desuperheater and pressure reducer 5 between the steam source and the heating medium passage, can maintain the steam entering the heating medium passage within a certain temperature range, reducing losses to the heat storage exchanger 10 and ensuring its stable and safe operation. The main steam pipeline of the supercritical unit is generally made of ASTM A335 P91 chromium-molybdenum steel or ASTM A335 P92 chromium-molybdenum-vanadium steel. When the steam temperature decreases, the steam pipeline material can be 12Cr1MonVG steel pipe or 12CrMonV steel pipe. Water spray desuperheating effectively reduces the extracted steam temperature, maintains a constant pipeline temperature, and lowers the grade of pipeline materials used. That is, the steam pipelines downstream of the desuperheater and pressure reducer 5 can all use consistent, relatively low-grade materials, reducing initial investment and operation and maintenance costs. When steam pipelines use the same materials, on the one hand, the same pipeline materials exhibit consistent responses and tolerance to external influences, resulting in greater performance stability; on the other hand, the same pipeline materials respond consistently to indicators such as stress strength and sealing performance, reducing local weak points caused by material differences and improving the overall reliability and safety of the pipeline system.

[0030] Similarly, a desuperheater 17 is also installed between the steam accumulator 23 and the heating medium passage to ensure that the steam temperature entering the steam accumulator 23 reaches the set temperature at the steam inlet of the steam accumulator 23. This ensures that the steam accumulator 23 operates under safe and stable conditions and protects the steam pipeline downstream of the desuperheater 17. On the other hand, the pipeline before water spray desuperheating is made of Cr-Mo alloy steel and Inconel 625 nickel-based alloy. After the steam is desuperheated by water spray, the pipeline material is usually carbon steel and Austenic 304 stainless steel. Therefore, by installing the desuperheater 17, the material grade of the downstream pipeline can be further reduced, thus reducing pipe costs.

[0031] In this invention, along the steam supply direction, a first shut-off valve 2, a hydraulic quick-closing valve 3, and a flow meter 4 are sequentially arranged between the steam source and the desuperheater / pressure reducer 5. The flow meter 4 is used to monitor the steam flow rate. When the thermal storage process ends, the first shut-off valve 2 is closed, and the hydraulic quick-closing valve 3 can quickly switch its position in a very short time to rapidly isolate the thermal storage system, minimize potential risks, and enhance the overall safety of the system.

[0032] To control the amount of sprayed cold water, a first regulating valve group 25 for adjusting the cold medium supply flow rate is provided between the cold medium source and the desuperheating and pressure reducing device 5 in this invention. The first regulating valve group 25 includes a second shut-off valve 6, a first regulating valve 7, and a third shut-off valve 8 arranged sequentially along the cold medium supply direction. The first regulating valve 7 is used to regulate the flow rate of the cold medium and, together with the desuperheating and pressure reducing device 5, controls the desuperheating and pressure reducing process of the extracted steam. The third shut-off valve 8 is used for maintenance isolation of the first regulating valve group 25 and forms a double protection with the second shut-off valve 6.

[0033] In this invention, a safety valve 9 is installed on the pipeline between the de-cooling and pressure reducing device 5 and the heat storage transducer to prevent excessive pressure in the pipeline.

[0034] In this invention, a second regulating valve group 26 for adjusting the industrial steam supply flow is provided on the steam supply pipeline; the second regulating valve group 26 includes a fifth shut-off valve 13, a second regulating valve 12 and a fourth shut-off valve 11 arranged sequentially along the steam supply direction, for flexible control of the industrial steam supply flow.

[0035] In this invention, a third regulating valve group 27 is provided between the cold medium source and the desuperheater 17 to regulate the flow rate of the cold medium supplied by the cold medium source. The third regulating valve group 27 includes a sixth shut-off valve 14, a third regulating valve 15, and a seventh shut-off valve 16 arranged sequentially along the cold medium supply direction. During this process, the opening degree of the third regulating valve 15 in the third regulating valve group 27 can be adjusted to control the flow rate of the cold medium, and together with the desuperheater 17, the steam inlet parameters of the steam accumulator 23 can be controlled to achieve flexible control of the heat storage rate of the steam accumulator 23.

[0036] In this invention, an eighth shut-off valve 22 is provided at the steam inlet of the steam accumulator 23. A check valve 21 is provided in front of the eighth shut-off valve 22 along the steam supply direction to prevent steam backflow. The steam accumulator 23 is equipped with a pressure sensor for measuring its internal pressure. When the pressure sensor measures that the internal pressure of the steam accumulator 23 reaches the designed full storage pressure (which can be 90% to 95% of the upper pressure limit), the eighth shut-off valve 22 is closed and the second regulating valve group 26 is opened (the second regulating valve group 26 can be opened appropriately earlier than the eighth shut-off valve 22). If the pressure inside the steam accumulator 23 has not reached 100% of the upper pressure limit, the eighth shut-off valve 22 is closed in advance and the second regulating valve group 26 is opened, which can compensate for the opening delay of the second regulating valve group 26.

[0037] In this invention, the steam accumulator 23 is connected to a water source via a water supply pump 24, which is used to regulate the liquid level in the steam accumulator 23 and control the drop in liquid level caused by long-term operation of the steam accumulator 23. The steam energy storage system also includes a drainage mechanism for draining the steam accumulator 23. A conventional device can be used for the drainage mechanism.

[0038] Specific examples: In one embodiment of the present invention, the application is a 1000MW ultra-supercritical once-through reheat unit. In order to improve the unit's load increase rate, the thermal storage method of the molten salt coupled steam accumulator full-energy thermal storage technology proposed in this invention is coupled into the unit to further improve the unit's flexibility.

[0039] This embodiment only discusses the heat storage stage of the system operation process. The specific technical route is as follows: During the 75% THA (Turbine Heat Acceptance) period of the unit, 50 t / h of reheat hot section steam (parameters 3.8 MPa, 622℃) is extracted. After depressurization, it is mixed with the cold medium provided by the cold medium source to achieve de-temperature and depressurization of the steam. At this time, the steam parameters are 3 MPa and 440℃. This steam continues to be sent to the heat storage heat exchanger 10, where part of the sensible heat is stored in the high-temperature molten salt tank 18. The steam after heat exchange is sent to the steam accumulator 23 to store the remaining sensible heat and all latent heat of the steam.

[0040] Specifically, if both the high-temperature molten salt tank 18 and the steam accumulator 23 have just begun storing heat, when the power of the molten salt pump 19 is adjusted so that the outlet flow rate of the low-temperature molten salt tank 20 reaches 46.72 t / h, the steam parameters after the heat exchanger 10 are 3 MPa and 330℃. After 0.69 hours, both the high-temperature molten salt tank 18 and the steam accumulator 23 will be just full.

[0041] When the power of the molten salt pump 19 is reduced and the flow rate of the low-temperature molten salt is adjusted to 33.64 t / h, the steam parameters after the heat storage heat exchanger 10 are 3 MPa and 360℃. The steam accumulator 23 can be filled in 0.67 hours. At this time, the eighth shut-off valve 22 is closed, the fourth shut-off valve 11 and the fifth shut-off valve 13 in the second regulating valve group 26 are opened, and the opening degree of the second regulating valve 12 is adjusted. At the same time, the power of the molten salt pump 19 can be adjusted according to the industrial steam supply parameter requirements, the flow rate of the molten salt at the outlet of the low-temperature molten salt tank 20 can be controlled, and the steam parameters at the outlet of the heat supply medium of the heat storage heat exchanger 10 can be flexibly adjusted to achieve industrial steam supply with different parameters.

[0042] When the power of the molten salt pump 19 is increased and the flow rate of the low-temperature molten salt is adjusted to 55.74 t / h, the steam parameters after the heat storage heat exchanger 10 are 3 MPa and 310℃. The high-temperature molten salt tank 18 can be filled in 0.58 hours. At this time, the molten salt pump 19 is stopped, the sixth shut-off valve 14 and the seventh shut-off valve 16 in the third regulating valve group 27 are opened, and the opening degree of the third regulating valve 15 is adjusted to mix the steam with the cold medium provided by the cold medium source. The steam inlet parameters of the steam accumulator 23 can be controlled to achieve flexible control of the heat storage rate of the steam accumulator 23.

[0043] In practice, it has been proven that after the above-mentioned unit is coupled with the molten salt coupled steam accumulator full energy thermal storage technology of the present invention, the steam heat discharged by the unit is fully utilized, and the adjustment is very flexible for different situations, which enhances the adaptability and economy of the system in energy management at multiple time scales.

[0044] Any adaptive changes made according to actual needs are within the scope of protection of this invention.

[0045] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A thermal storage method of a molten salt coupled steam accumulator all-thermal energy storage technology, characterized by, The application discloses a full energy storage technology based on a molten salt coupled steam accumulator full energy storage system, which comprises a molten salt storage system, a steam accumulator storage system and a storage control system. The molten salt storage system comprises a low-temperature molten salt tank, a high-temperature molten salt tank and a storage heat exchanger, the storage heat exchanger has a storage medium passage and a heat supply medium passage, the low-temperature molten salt tank and the high-temperature molten salt tank are communicated with the medium inlet and the medium outlet of the storage medium passage respectively. The steam accumulator storage system comprises a steam accumulator, the steam inlet end of the steam accumulator is communicated with the medium outlet of the heat supply medium passage. The storage control system comprises a steam supply pipeline, a first adjusting valve group, a second adjusting valve group and a third adjusting valve group, the steam supply pipeline comprises a front steam pipeline and a rear steam pipeline, the front steam pipeline is communicated with a steam source and the medium inlet of the heat supply medium passage, the rear steam pipeline is communicated with the medium outlet of the heat supply medium passage and the steam inlet end of the steam accumulator, a desuperheater is arranged on the front steam pipeline, the desuperheater is communicated with a cold medium source through the first adjusting valve group, the steam inlet end of the second adjusting valve group is communicated with the rear steam pipeline, the communication position is located between the storage heat exchanger and the steam accumulator, and the steam outlet end of the second adjusting valve group is communicated with an industrial steam supply device. A desuperheater is further arranged on the rear steam pipeline, the desuperheater is located between the steam inlet end of the second adjusting valve group and the steam accumulator, the desuperheater is communicated with a cold medium source through the third adjusting valve group, and the cold medium source is used for cooling the steam passing through the desuperheater. The storage method comprises the following steps. The steam supply pipeline supplies steam, the second adjusting valve group and the third adjusting valve group are closed, the first adjusting valve group is opened, the desuperheater is supplied with cold medium, the steam passing through the desuperheater is cooled, the cooled steam enters the heat supply medium passage, the low-temperature molten salt in the low-temperature molten salt tank enters the storage medium passage, the low-temperature molten salt exchanges heat with the steam, the temperature of the low-temperature molten salt is increased, the low-temperature molten salt enters the high-temperature molten salt tank, and the low-temperature steam enters the steam accumulator to store energy. When the steam accumulator is filled with heat before the high-temperature molten salt tank, the second adjusting valve group is opened, the steam flowing out of the storage medium passage is used for industrial steam supply or is sent back to a unit thermal system through the second adjusting valve group. When the high-temperature molten salt tank is filled with heat before the steam accumulator, the molten salt pump stops working, the third adjusting valve group is opened, the desuperheater is supplied with cold medium, and the steam entering the steam accumulator is cooled.

2. The thermal storage method of the molten salt coupled steam accumulator all-thermal energy storage technology according to claim 1, characterized in that, A molten salt pump is arranged between the low-temperature molten salt tank and the heat supply medium passage and is used for providing power for the flow of the molten salt, and the molten salt pump can adjust the flow of the molten salt.

3. The thermal storage method of the molten salt coupled steam accumulator all-thermal energy storage technology according to claim 2, characterized in that, A liquid level sensor is arranged in the high-temperature molten salt tank and is used for measuring the liquid level height of the high-temperature molten salt, when the liquid level sensor measures that the liquid level of the high-temperature molten salt reaches a designed full storage liquid level, the molten salt pump is closed, and the third adjusting valve group is opened.

4. The thermal storage method of the molten salt coupled steam accumulator all-thermal energy storage technology according to claim 2, characterized in that, A first shutoff valve, a hydraulic quick-closing valve and a flow meter are sequentially arranged between the steam source and the desuperheater in the steam supply direction.

5. The thermal storage method of the molten salt coupled steam accumulator all-thermal energy storage technology according to claim 3, characterized in that, The first regulating valve group comprises a second shutoff valve, a first regulating valve and a third shutoff valve sequentially arranged in the cold medium supply direction.

6. The thermal storage method of the molten salt coupled steam accumulator all-thermal energy storage technology according to claim 4, characterized in that, The second regulating valve group comprises a fifth shutoff valve, a second regulating valve and a fourth shutoff valve sequentially arranged in the steam supply direction.

7. The thermal storage method of the molten salt coupled steam accumulator all-thermal energy storage technology according to claim 5, characterized in that, The third regulating valve group comprises a sixth shutoff valve, a third regulating valve and a seventh shutoff valve sequentially arranged in the cold medium supply direction.

8. The thermal storage method of the molten salt coupled steam accumulator all-thermal energy storage technology according to claim 6, characterized in that, An eighth shutoff valve is arranged at the steam inlet of the steam accumulator, and a check valve is arranged in front of the eighth shutoff valve in the steam supply direction.

9. The thermal storage method of the molten salt coupled steam accumulator all-thermal energy storage technology according to claim 8, characterized in that, A pressure sensor for measuring the internal pressure of the steam accumulator is arranged in the steam accumulator, and when the pressure sensor measures that the internal pressure of the steam accumulator reaches the design full storage pressure value, the eighth shutoff valve is closed and the second regulating valve group is opened.

10. The thermal storage method of the molten salt coupled steam accumulator all-thermal energy storage technology according to claim 9, characterized in that, The steam accumulator is connected to a water supply source through a water supply pump.

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