A high-temperature molten salt deep peak-shaving heat storage system

Abstract

The present invention discloses a high-temperature molten salt deep peak-shaving heat storage system, comprising a main steam unit, a main steam molten salt heat exchanger, a hot section molten salt heat exchanger, a cold reheat steam unit, an auxiliary steam unit, a cold salt tank, a hot salt tank, a low-pressure cylinder, a medium-pressure cylinder, a high-pressure cylinder and a detection unit. The main steam in the main steam unit enters the main steam molten salt heat exchanger for heating the molten salt, and enters the high-pressure cylinder to perform work in the other way. After the main steam molten salt heat exchanger and the exhaust steam in the high-pressure cylinder are combined, the main steam enters the cold reheat steam unit to form reheat steam, and enters the auxiliary steam unit to supplement steam to the low-pressure cylinder. By improving the exhaust structure of the deep peak-shaving heat storage system, a closed-loop control loop is formed, and corresponding detection units are provided to realize intelligent detection of the system under low-load operation, and accurately control the supply temperature of the turbine set. At the same time, by providing the auxiliary steam unit, the flow through the low-pressure cylinder is maintained at above 30% load, ensuring safe and stable operation of the turbine at low load.

Description

Technical Field

[0001] The present invention relates to a high-temperature molten salt deep peak regulation heat storage system, belonging to the technical field of thermal power generation. Background Art

[0002] The installed capacity of new energy wind and solar power generation is developing rapidly, and the proportion of power generation is increasing. The power system urgently needs a large proportion of flexible power sources to improve the power structure, alleviate the system peak-shaving pressure, and solve the problem of new energy power consumption.

[0003] Currently, the flexibility improvements for thermal power units are primarily limited by the limited depth of boiler peak-shaving, and insufficient unit economics and safety. Frequent, drastic adjustments shorten the lifespan of thermal power units and result in lower returns. Long-term operation at low load rates significantly reduces the unit's safety, economy, and environmental performance, which is inconsistent with the overall goal of energy conservation and consumption reduction. Therefore, to accommodate deep peak-shaving, steam turbine units must adhere to the required temperature change rate and control the main steam and reheat steam temperatures within the lower limit during operation. However, existing deep peak-shaving heat storage systems lack appropriate testing facilities and structural improvements, resulting in inaccurate control of the turbine supply temperature. This can easily damage the turbine units due to long-term operation. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a high-temperature molten salt deep peak-shaving heat storage system to solve the technical problems mentioned in the prior art.

[0005] A high-temperature molten salt deep peak-shaving heat storage system, comprising a main steam unit, a main steam molten salt heat exchanger, a hot section molten salt heat exchanger, a cold reheat steam unit, an auxiliary steam unit, a cold salt tank, a hot salt tank, a low-pressure cylinder, a medium-pressure cylinder, a high-pressure cylinder, and a detection unit;

[0006] The air outlet of the main steam unit is connected to the air inlet of the main steam molten salt heat exchanger through a first-level pipeline, the air outlet of the main steam molten salt heat exchanger is connected to the air inlet of the cold reheat steam unit through a second-level pipeline, the air outlet of the cold reheat steam unit is connected to the air inlet of the hot section molten salt heat exchanger through a third-level pipeline, the air outlet of the hot section molten salt heat exchanger is connected to the air inlet of the low-pressure cylinder through a fourth-level pipeline, the air outlet of the low-pressure cylinder is connected to the air inlet of the main steam molten salt heat exchanger through a fifth-level pipeline, and the air inlet end of the first-level pipeline is connected to the air inlet of the high-pressure cylinder through a sixth-level pipeline. At the gas end, the gas outlet of the high-pressure cylinder is connected to the gas inlet of the secondary pipeline through a seventh-level pipeline, the gas inlet of the third-level pipeline is connected to the gas inlet of the medium-pressure cylinder through an eighth-level pipeline, the gas outlet of the medium-pressure cylinder is connected to the gas outlet of the fifth-level pipeline through a ninth-level pipeline, the gas inlet of the second-level pipeline is connected to the gas inlet of the auxiliary steam unit through a tenth-level pipeline, and the gas outlet of the auxiliary steam unit is connected to the fourth-level pipeline through an eleventh-level pipeline. Corresponding electronic valve groups are respectively provided on each level of the pipeline, and the electronic valve groups are connected to a controller for controlling the on-off and flow rate of the corresponding pipeline;

[0007] The main steam in the main steam unit enters the main steam molten salt heat exchanger to heat the molten salt, and enters the high-pressure cylinder to perform work. After the main steam molten salt heat exchanger and the exhaust steam in the high-pressure cylinder are combined, the main steam enters the cold reheat steam unit to form reheat steam, and enters the auxiliary steam unit to supply steam to the low-pressure cylinder.

[0008] The reheated steam enters the hot section molten salt heat exchanger to heat the molten salt, and enters the intermediate pressure cylinder to perform work. The exhaust steam in the hot section molten salt heat exchanger enters the low pressure cylinder to perform work. The exhaust steam of the low pressure cylinder and the intermediate pressure cylinder are combined and sent to the main steam unit.

[0009] The molten salt extracted from the cold salt tank enters the main steam molten salt heat exchanger and the hot section molten salt heat exchanger for heating, and the heated molten salt is introduced into the hot salt tank for storage to achieve thermal energy storage;

[0010] The detection units are used to detect the steam input temperatures of the main steam molten salt heat exchanger, hot section molten salt heat exchanger, low-pressure cylinder, medium-pressure cylinder, high-pressure cylinder, cold reheat steam unit and auxiliary steam unit respectively, obtain temperature detection information and feed it back to the controller, and the controller adjusts the input temperature of each section of steam according to the temperature detection information.

[0011] Optionally, a molten salt pump is provided between the cold salt tank and the main steam molten salt heat exchanger and the hot section molten salt heat exchanger, and the operating temperature of the molten salt pump is set to 280-300°C.

[0012] Optionally, two groups of molten salt pumps are provided, and the input ends of the two groups of molten salt pumps are respectively connected to the cold salt tank through pipelines;

[0013] The output ends of one group of the molten salt pumps are connected to the feed ports of the main steam molten salt heat exchanger and the hot section molten salt heat exchanger respectively through main pipelines, and the feed ends of the main pipelines are sequentially provided with a first butterfly valve and a first stop valve along the flow direction of the molten salt;

[0014] The output end of another group of molten salt pumps is connected to the discharge end of the first stop valve through an auxiliary pipeline, and the feed end of the auxiliary pipeline is sequentially provided with a second butterfly valve and a second stop valve along the flow direction of the molten salt.

[0015] Optionally, the feed ports of the main steam molten salt heat exchanger and the hot section molten salt heat exchanger are respectively provided with electronic gate valves, the discharge ports of the main steam molten salt heat exchanger and the hot section molten salt heat exchanger are connected to the hot salt tank through pipelines, and the feed port of the hot salt tank is provided with a two-position three-way pneumatic solenoid valve.

[0016] Optionally, a first-stage unloading pipeline is provided on the main pipeline between the first butterfly valve and the first stop valve, and a third stop valve is provided on the first-stage unloading pipeline;

[0017] A secondary unloading pipeline is provided on the auxiliary pipeline between the second butterfly valve and the second stop valve, and a fourth stop valve is provided on the secondary unloading pipeline;

[0018] The other ends of the first-level unloading pipeline and the second-level unloading pipeline are respectively connected to the cold salt tank.

[0019] Optionally, the detection unit includes:

[0020] a first temperature detection module, the first temperature detection module being installed on the primary pipeline and being used to detect an input temperature of steam in the primary pipeline;

[0021] a second temperature detection module, the second temperature detection module being installed on the six-stage pipeline and being used to detect the input temperature of the steam in the six-stage pipeline;

[0022] a third temperature detection module, the third temperature detection module being installed on the secondary pipeline and being used to detect the input temperature of the steam in the sixth-level pipeline;

[0023] a fourth temperature detection module, the fourth temperature detection module being installed on the tertiary pipeline and being used to detect the input temperature of the steam in the tertiary pipeline;

[0024] a fifth temperature detection module, the fifth temperature detection module being installed on the eight-stage pipeline and being used to detect the input temperature of steam in the eight-stage pipeline;

[0025] a sixth temperature detection module and a seventh temperature detection module, the sixth temperature detection module and the seventh temperature detection module being respectively located on both sides of the electronic valve group on the four-stage pipeline, the sixth temperature detection module being installed at the steam inlet end of the four-stage pipeline, and the seventh temperature detection module being installed at the steam outlet end of the four-stage pipeline, for detecting the input temperature of the steam in the four-stage pipeline;

[0026] an eighth temperature detection module, the eighth temperature detection module being installed on the ten-stage pipeline and being used to detect the input temperature of the steam in the ten-stage pipeline;

[0027] The first temperature detection module, the second temperature detection module, the third temperature detection module, the fourth temperature detection module, the fifth temperature detection module, the sixth temperature detection module, the seventh temperature detection module and the eighth temperature detection module are respectively connected to the controller.

[0028] Optionally, the detection unit is provided with at least a temperature sensor, and the test probes of the temperature sensor are respectively placed in each stage of the pipeline to collect temperature information of the steam in the corresponding pipeline and feed it back to the controller.

[0029] Optionally, a flow detection sensor is provided on the main pipeline at the discharge end of the auxiliary pipeline, and the flow detection sensor is connected to the controller to detect the conveying flow of the molten salt in the main pipeline.

[0030] The beneficial effects that the present invention can produce include:

[0031] The high-temperature molten salt deep peak-shaving heat storage system provided by the present invention improves the exhaust structure of the deep peak-shaving heat storage system to form a closed-loop control circuit, and sets corresponding detection units to realize intelligent detection of the system under low-load operation, thereby making up for the lack of corresponding detection facilities in the existing deep peak-shaving heat storage system, accurately controlling the supply temperature of the turbine unit, and avoiding damage to the turbine unit caused by long-term operation. At the same time, by setting an auxiliary steam unit, the flow through the low-pressure cylinder is maintained at above 30% load, ensuring safe and stable operation of the turbine at low load. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a structural schematic diagram of a high-temperature molten salt deep peak-shaving heat storage system according to the present invention;

[0033] In the figure: 1. Main steam unit, 2. Main steam molten salt heat exchanger, 3. Hot section molten salt heat exchanger, 4. Cold reheat steam unit, 5. Auxiliary steam unit, 6. Cold salt tank, 7. Hot salt tank, 8. Low-pressure cylinder, 9. Medium-pressure cylinder, 10. High-pressure cylinder, 11. First-level pipeline, 12. Second-level pipeline, 13. Third-level pipeline, 14. Fourth-level pipeline, 15. Fifth-level pipeline, 16. Sixth-level pipeline, 17. Seventh-level pipeline, 18. Eighth-level pipeline, 19. Ninth-level pipeline, 20. Tenth-level pipeline, 21. Eleventh-level pipeline, 22. First stop valve, 23. Second stop valve, 24. Third stop valve , 25. Fourth stop valve, 26. First butterfly valve, 27. Second butterfly valve, 28. Main pipeline, 29. Auxiliary pipeline, 30. Molten salt pump, 31. Two-position three-way pneumatic solenoid valve, 32. Flow detection sensor, 33. First temperature detection module, 34. Second temperature detection module, 35. Third temperature detection module, 36. Fourth temperature detection module, 37. Fifth temperature detection module, 38. Sixth temperature detection module, 39. Seventh temperature detection module, 40. Eighth temperature detection module, 41. First unloading pipeline, 42. Secondary unloading pipeline, 43. Electronic gate valve. DETAILED DESCRIPTION

[0034] The present invention is described in detail below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0035] like Figure 1 As shown, the present invention provides a high-temperature molten salt deep peak-shaving heat storage system, including a main steam unit 1, a main steam molten salt heat exchanger 2, a hot section molten salt heat exchanger 3, a cold reheat steam unit 4, an auxiliary steam unit 5, a cold salt tank 6, a hot salt tank 7, a low-pressure cylinder 8, a medium-pressure cylinder 9, a high-pressure cylinder 10 and a detection unit;

[0036] The air outlet of the main steam unit 1 is connected to the air inlet of the main steam molten salt heat exchanger 2 through the first-level pipe 11, the air outlet of the main steam molten salt heat exchanger 2 is connected to the air inlet of the cold reheat steam unit 4 through the second-level pipe 12, the air outlet of the cold reheat steam unit 4 is connected to the air inlet of the hot section molten salt heat exchanger 3 through the third-level pipe 13, the air outlet of the hot section molten salt heat exchanger 3 is connected to the air inlet of the low-pressure cylinder 8 through the fourth-level pipe 14, the air outlet of the low-pressure cylinder 8 is connected to the air inlet of the main steam molten salt heat exchanger 2 through the fifth-level pipe 15, the air inlet end of the first-level pipe 11 is connected to the air inlet of the high-pressure cylinder 10 through the sixth-level pipe 16 The outlet end of the high-pressure cylinder 10 is connected to the inlet end of the secondary pipeline 12 through the seventh-level pipeline 17, the inlet end of the third-level pipeline 13 is connected to the inlet end of the medium-pressure cylinder 9 through the eighth-level pipeline 18, the outlet end of the medium-pressure cylinder 9 is connected to the outlet end of the fifth-level pipeline 15 through the ninth-level pipeline 19, the inlet end of the second-level pipeline 12 is connected to the inlet of the auxiliary steam unit 5 through the tenth-level pipeline 20, and the outlet of the auxiliary steam unit 5 is connected to the fourth-level pipeline 14 through the eleventh-level pipeline 21. Corresponding electronic valve groups are respectively provided on each level of the pipeline, and the electronic valve groups are connected to the controller for controlling the on-off and flow rate of the corresponding pipeline;

[0037] The main steam in the main steam unit 1 enters the main steam molten salt heat exchanger 2 to heat the molten salt, and enters the high-pressure cylinder 10 to perform work. After the main steam molten salt heat exchanger 2 and the exhaust steam in the high-pressure cylinder 10 are combined, one path enters the cold reheat steam unit 4 to form reheat steam, and the other path enters the auxiliary steam unit 5 to be used as steam supplement for the low-pressure cylinder 8;

[0038] The reheated steam enters the hot section molten salt heat exchanger 3 to heat the molten salt, and the other path enters the intermediate pressure cylinder 9 to perform work. The exhaust steam in the hot section molten salt heat exchanger 3 enters the low pressure cylinder 8 to perform work. The exhaust steam of the low pressure cylinder 8 and the intermediate pressure cylinder 9 are combined and sent to the main steam unit 1;

[0039] The molten salt extracted from the cold salt tank 6 enters the main steam molten salt heat exchanger 2 and the hot section molten salt heat exchanger 3 for heating, and the heated molten salt is introduced into the hot salt tank 7 for storage to achieve thermal energy storage;

[0040] The detection unit detects the steam input temperature of the main steam molten salt heat exchanger 2, the hot section molten salt heat exchanger 3, the low-pressure cylinder 8, the medium-pressure cylinder 9, the high-pressure cylinder 10, the cold reheat steam unit 4 and the auxiliary steam unit 5 respectively, obtains the temperature detection information and feeds it back to the controller, and the controller adjusts the input temperature of each section of steam according to the temperature detection information.

[0041] It should be noted that, in this embodiment, both the main steam unit 1 and the cold reheat steam unit 4 may adopt boilers, and the steam temperature in the main steam unit 1 is set to be higher than the steam temperature in the cold reheat steam unit 4 .

[0042] Furthermore, a molten salt pump 30 is provided between the cold salt tank 6 and the main steam molten salt heat exchanger 2 and the hot section molten salt heat exchanger 3. The operating temperature of the molten salt pump 30 is set to 280-300°C.

[0043] In this embodiment, the temperature value of the molten salt in the cold salt tank 6 is set to 290°C; wherein, an electric heater is provided in the cold salt tank 6 to heat the temperature of the molten salt in the cold salt tank 6 to 290°C, and then output through the molten salt pump 30, so as to avoid the temperature of the molten salt in the cold salt tank 6 being too low, resulting in the main steam molten salt heat exchanger 2 and the hot section molten salt heat exchanger 3 to absorb a large amount of heat in the steam, resulting in insufficient steam intake of the intermediate pressure cylinder 9 and the low pressure cylinder 8 of the turbine, thereby ensuring the normal operation of the turbine.

[0044] Furthermore, two groups of molten salt pumps 30 are provided, and the input ends of the two groups of molten salt pumps 30 are respectively connected to the cold salt tank 6 through pipelines;

[0045] The output end of one group of molten salt pumps 30 is connected to the feed inlets of the main steam molten salt heat exchanger 2 and the hot section molten salt heat exchanger 3 respectively through the main pipeline 28. The feed end of the main pipeline 28 is sequentially provided with a first butterfly valve 26 and a first stop valve 22 along the flow direction of the molten salt. This group of molten salt pumps 30 is used normally as the main molten salt pump;

[0046] The output end of another group of molten salt pumps 30 is connected to the discharge end of the first stop valve 22 through an auxiliary pipe 29. The feed end of the auxiliary pipe 29 is sequentially provided with a second butterfly valve 27 and a second stop valve 23 along the flow direction of the molten salt. This group of molten salt pumps 30 is used as an auxiliary molten salt pump for backup. When the main molten salt pump is damaged, the auxiliary molten salt pump is started to maintain the normal operation of the heat storage system.

[0047] Furthermore, the feed ports of the main steam molten salt heat exchanger 2 and the hot section molten salt heat exchanger 3 are respectively provided with electronic gate valves 43, and the discharge ports of the main steam molten salt heat exchanger 2 and the hot section molten salt heat exchanger 3 are connected to the hot salt tank 7 through pipes, and the feed port of the hot salt tank 7 is provided with a two-position three-way pneumatic solenoid valve 31; when the thermal power unit is deeply adjusted to low load operation, the main molten salt pump is first started, and the first butterfly valve 26, the first stop valve 22 and the electronic gate valve 43 corresponding to the heat exchanger to be absorbed this time are opened, and the low-temperature molten salt in the cold salt tank 6 is pumped into the corresponding heat exchanger through the main pipeline 28, and after absorbing the heat of the main steam or reheated steam, high-temperature molten salt is obtained (the temperature of the high-temperature molten salt is set to 540-580°C in this embodiment), and then the two-position three-way pneumatic solenoid valve 31 is opened to introduce the high-temperature molten salt into the hot salt tank 7 for storage, thereby realizing thermal energy storage.

[0048] Furthermore, a first-level unloading pipe 41 is connected to the main pipe 28 between the first butterfly valve 26 and the first stop valve 22, and a third stop valve 24 is installed on the first-level unloading pipe 41. A second-level unloading pipe 42 is connected to the auxiliary pipe 29 between the second butterfly valve 27 and the second stop valve 23, and a fourth stop valve 25 is installed on the second-level unloading pipe 42. The other ends of the first-level unloading pipe 41 and the second-level unloading pipe 42 are respectively connected to the cold salt tank 6, which is used to discharge the residual molten salt in the main pipe 28 and the auxiliary pipe 29 after the molten salt pump 30 stops working, so as to avoid corrosion of the pipe by the molten salt.

[0049] Specifically, the molten salt pump 30 has two working modes:

[0050] In normal working mode, the main molten salt pump is started to transport the molten salt in the cold salt tank 6. When the main molten salt pump stops working, the third stop valve 24 is opened to return the molten salt in the main pipeline 28 to the cold salt tank 6 through the first-level unloading pipeline 41. After the molten salt in the main pipeline 28 is returned, the first stop valve 22 and the third stop valve 24 are controlled to be closed; in this embodiment, the operating mode of the first butterfly valve 26 is synchronized with that of the main molten salt pump, that is, when the main molten salt pump is started, the first butterfly valve 26 is opened, and when the main molten salt pump is stopped, the first butterfly valve 26 is closed.

[0051] In the standby working mode, the auxiliary molten salt pump is started to transport the molten salt in the cold salt tank 6. When the auxiliary molten salt pump stops working, the fourth stop valve 25 is opened to return the molten salt in the main pipeline 28 to the cold salt tank 6 through the auxiliary pipeline 29 and the secondary unloading pipeline 42. After the molten salt in the main pipeline 28 is returned, the second stop valve 23 and the fourth stop valve 25 are controlled to be closed; in this embodiment, the operating mode of the second butterfly valve 27 is synchronized with the auxiliary molten salt pump, that is, when the auxiliary molten salt pump is started, the second butterfly valve 27 is opened, and when the auxiliary molten salt pump is stopped, the second butterfly valve 27 is closed.

[0052] In this embodiment, the heat exchanger to absorb heat this time is selected according to the temperature detection information of the detection unit, wherein the detection unit includes:

[0053] A first temperature detection module 33 is installed on the primary pipeline 11 and is used to detect the input temperature of steam in the primary pipeline 11;

[0054] A second temperature detection module 34 is installed on the six-stage pipeline 16 and is used to detect the input temperature of steam in the six-stage pipeline 16;

[0055] The third temperature detection module 35 is installed on the secondary pipeline 12 and is used to detect the input temperature of the steam in the sixth-level pipeline 16;

[0056] A fourth temperature detection module 36 is installed on the tertiary pipeline 13 and is used to detect the input temperature of the steam in the tertiary pipeline 13;

[0057] A fifth temperature detection module 37 is installed on the eighth-stage pipeline 18 and is used to detect the input temperature of steam in the eighth-stage pipeline 18;

[0058] The sixth temperature detection module 38 and the seventh temperature detection module 39 are respectively located on both sides of the electronic valve group on the quaternary pipeline 14. The sixth temperature detection module 38 is installed at the steam inlet end of the quaternary pipeline 14, and the seventh temperature detection module 39 is installed at the steam outlet end of the quaternary pipeline 14, and is used to detect the input temperature of the steam in the quaternary pipeline 14;

[0059] An eighth temperature detection module 40 is installed on the ten-stage pipeline 20 and is used to detect the input temperature of steam in the ten-stage pipeline 20;

[0060] The first temperature detection module 33 , the second temperature detection module 34 , the third temperature detection module 35 , the fourth temperature detection module 36 , the fifth temperature detection module 37 , the sixth temperature detection module 38 , the seventh temperature detection module 39 and the eighth temperature detection module 40 are respectively connected to the controller.

[0061] Specifically, the detection unit is provided with at least a temperature sensor, and the test probes of the temperature sensor are respectively placed in the pipelines at each level, for collecting the temperature information of the steam in the corresponding pipeline and feeding it back to the controller.

[0062] In this embodiment, the input temperature of the steam in the heat storage system is detected in sections by using multiple groups of temperature detection modules, so as to perform intelligent detection of heat storage in the system under low-load operation and adjust the input temperature of the steam in each section of the pipeline, wherein:

[0063] According to the temperature detection information of the first temperature detection module 33 and the second temperature detection module 34, the main steam output flow rate and output temperature of the main steam unit 1 are adjusted to meet the steam input temperature of the high-pressure cylinder 10, so that the main steam in the main steam unit 1 enters the main steam molten salt heat exchanger 2 for molten salt heating treatment, and enters the high-pressure cylinder 10 to perform work in the other direction. Then, after the main steam molten salt heat exchanger 2 and the exhaust steam in the high-pressure cylinder 10 are combined, they enter the cold reheat steam unit 4 to form reheat steam, and the third temperature detection module 35 is used to detect the input temperature of the steam in the cold reheat steam unit 4 to determine whether it is necessary to heat the steam entering the cold reheat steam unit 4, wherein;

[0064] When the steam entering the cold reheat steam unit 4 meets the output temperature of the intermediate pressure cylinder 9, the cold reheat steam unit 4 is controlled so as not to heat the steam entering the cold reheat steam unit 4;

[0065] When the steam entering the cold reheat steam unit 4 is higher than the output temperature of the intermediate pressure cylinder 9, the molten salt in the cold salt tank 6 is pumped into the main steam molten salt heat exchanger 2 to absorb and store excess heat. Then, the exhaust steam from the main steam molten salt heat exchanger 2 and the high pressure cylinder 10 is combined, and then enters the cold reheat steam unit 4 and the auxiliary steam unit 5. The input temperature of the steam in each branch is detected by the third temperature detection module 35 and the eighth temperature detection module 40.

[0066] When the steam entering the cold reheat steam unit 4 is lower than the output temperature of the intermediate pressure cylinder 9 , the entering steam is heated by the cold reheat steam unit 4 .

[0067] Then, the output temperature of the reheated steam of the cold reheated steam unit 4 is detected by the fourth temperature detection module 36 and the fifth temperature detection module 37 to adjust the output flow and output temperature of the reheated steam of the cold reheated steam unit 4 so that it meets the steam input temperature of the intermediate pressure cylinder 9, so that the reheated steam enters the hot section molten salt heat exchanger 3 for heating the molten salt and enters the intermediate pressure cylinder 9 for work. Then, the exhaust steam in the hot section molten salt heat exchanger 3 enters the low pressure cylinder 8 for work, and the output temperature of the exhaust steam in the hot section molten salt heat exchanger 3 is detected by the sixth temperature detection module 38 and the seventh temperature detection module 39 to determine whether it meets the steam input temperature of the low pressure cylinder 8.

[0068] When the exhaust steam in the hot section molten salt heat exchanger 3 meets the steam input temperature of the low pressure cylinder 8, the exhaust steam in the hot section molten salt heat exchanger 3 is directly connected to the low pressure cylinder 8 to perform work;

[0069] When the exhaust steam in the hot section molten salt heat exchanger 3 is higher than the steam input temperature of the low pressure cylinder 8, the molten salt in the cold salt tank 6 is pumped into the hot section molten salt heat exchanger 3 to absorb and store excess heat;

[0070] When the exhaust steam in the hot section molten salt heat exchanger 3 is lower than the steam input temperature of the low-pressure cylinder 8, the hot section molten salt heat exchanger 3 is not used to absorb the heat of the reheated steam, but the steam in the auxiliary steam unit 5 is connected to the low-pressure cylinder 8 for steam supplement, and is detected by the seventh temperature detection module 39 to adjust the steam inlet flow rate of the auxiliary steam unit 5. Finally, the exhaust steam of the intermediate pressure cylinder 9 and the low-pressure cylinder 8 are collected and enter the main steam unit 1, thereby forming a closed-loop control loop, realizing intelligent detection of the system under low-load operation, to make up for the lack of corresponding detection facilities in the existing deep peak-shaving heat storage system, and accurately controlling the supply temperature of the turbine unit to avoid damage to the turbine unit caused by long-term operation, so that the flow through the low-pressure cylinder 8 is maintained at above 30% load, ensuring safe and stable operation of the turbine at low load.

[0071] It should be noted that: in this embodiment, the temperature of the main steam is reduced to 345°C after heat exchange in the main steam molten salt heat exchanger 2, and the temperature of the reheated steam is reduced to 335°C after heat exchange in the hot section molten salt heat exchanger 3.

[0072] Furthermore, a flow detection sensor 32 is provided on the main pipeline 28 at the discharge end of the auxiliary pipeline 29. The flow detection sensor 32 is connected to the controller and is used to detect the conveying flow rate of the molten salt in the main pipeline 28. When in transportation, if the flow detection sensor 32 detects that the conveying flow rate of the molten salt in the main pipeline 28 is lower than the set detection value, it is judged that abnormal operation such as damage has occurred, and the auxiliary molten salt pump is controlled to start.

[0073] The above descriptions are merely several embodiments of the present invention and do not constitute any form of limitation to the present invention. Although the present invention is disclosed as above in terms of preferred embodiments, they are not intended to limit the present invention. Any technician familiar with the present profession, without departing from the scope of the technical solution of the present invention, who makes slight changes or modifications using the technical contents disclosed above, is equivalent to an equivalent implementation case and falls within the scope of the technical solution.

Claims

1. A high-temperature molten salt deep peak-shaving heat storage system, characterized by: It comprises a main steam unit (1), a main steam molten salt heat exchanger (2), a hot section molten salt heat exchanger (3), a cold reheat steam unit (4), an auxiliary steam unit (5), a cold salt tank (6), a hot salt tank (7), a low-pressure cylinder (8), a medium-pressure cylinder (9), a high-pressure cylinder (10), and a detection unit; The air outlet of the main steam unit (1) is connected to the air inlet of the main steam molten salt heat exchanger (2) through a first-level pipe (11), the air outlet of the main steam molten salt heat exchanger (2) is connected to the air inlet of the cold reheat steam unit (4) through a second-level pipe (12), the air outlet of the cold reheat steam unit (4) is connected to the air inlet of the hot section molten salt heat exchanger (3) through a third-level pipe (13), the air outlet of the hot section molten salt heat exchanger (3) is connected to the air inlet of the low-pressure cylinder (8) through a fourth-level pipe (14), the air outlet of the low-pressure cylinder (8) is connected to the air inlet of the main steam molten salt heat exchanger (2) through a fifth-level pipe (15), and the air inlet end of the first-level pipe (11) is connected to the high-pressure cylinder (10) through a sixth-level pipe (16). ), the air outlet of the high-pressure cylinder (10) is connected to the air inlet of the secondary pipe (12) through a seventh-stage pipe (17), the air inlet of the third-stage pipe (13) is connected to the air inlet of the medium-pressure cylinder (9) through an eighth-stage pipe (18), the air outlet of the medium-pressure cylinder (9) is connected to the air outlet of the fifth-stage pipe (15) through a ninth-stage pipe (19), the air inlet of the second-stage pipe (12) is connected to the air inlet of the auxiliary steam unit (5) through a tenth-stage pipe (20), the air outlet of the auxiliary steam unit (5) is connected to the fourth-stage pipe (14) through an eleventh-stage pipe (21), and corresponding electronic valve groups are respectively provided on each stage of the pipe, and the electronic valve groups are connected to a controller for controlling the on-off and flow rate of the corresponding pipe; The main steam in the main steam unit (1) enters the main steam molten salt heat exchanger (2) to heat the molten salt, and enters the high-pressure cylinder (10) to perform work. After the exhaust steam from the main steam molten salt heat exchanger (2) and the high-pressure cylinder (10) is combined, the main steam enters the cold reheat steam unit (4) to form reheat steam, and enters the auxiliary steam unit (5) to supplement steam to the low-pressure cylinder (8). The reheated steam enters the hot section molten salt heat exchanger (3) to heat the molten salt, and enters the intermediate pressure cylinder (9) to perform work. The exhaust steam in the hot section molten salt heat exchanger (3) enters the low pressure cylinder (8) to perform work. The exhaust steam of the low pressure cylinder (8) and the intermediate pressure cylinder (9) are combined and sent to the main steam unit (1). The molten salt extracted from the cold salt tank (6) enters the main steam molten salt heat exchanger (2) and the hot section molten salt heat exchanger (3) for heating, and the heated molten salt is introduced into the hot salt tank (7) for storage, thereby realizing thermal energy storage; The detection units are used to detect the steam input temperatures of the main steam molten salt heat exchanger (2), the hot section molten salt heat exchanger (3), the low-pressure cylinder (8), the medium-pressure cylinder (9), the high-pressure cylinder (10), the cold reheat steam unit (4), and the auxiliary steam unit (5), respectively, to obtain temperature detection information and feed it back to the controller, and the controller adjusts the input temperature of each section of steam according to the temperature detection information; When the steam entering the cold reheat steam unit (4) meets the output temperature of the intermediate pressure cylinder (9), the cold reheat steam unit (4) is controlled so that the steam entering the cold reheat steam unit (4) does not need to be heated; When the steam entering the cold reheat steam unit (4) is higher than the output temperature of the intermediate pressure cylinder (9), the molten salt in the cold salt tank (6) is pumped into the main steam molten salt heat exchanger (2) to absorb and store excess heat, and then the exhaust steam from the main steam molten salt heat exchanger (2) and the high pressure cylinder (10) is collected, and then enters the cold reheat steam unit (4) and the auxiliary steam unit (5) on one side, and the input temperature of the steam in each branch is detected by the third temperature detection module (35) and the eighth temperature detection module (40); When the steam entering the cold reheat steam unit (4) is lower than the output temperature of the intermediate pressure cylinder (9), the entering steam is heated by the cold reheat steam unit (4); When the exhaust steam in the hot section molten salt heat exchanger (3) meets the steam input temperature of the low-pressure cylinder (8), the exhaust steam in the hot section molten salt heat exchanger (3) is directly connected to the low-pressure cylinder (8) to perform work; When the exhaust steam in the hot section molten salt heat exchanger (3) is higher than the steam input temperature of the low pressure cylinder (8), the molten salt in the cold salt tank (6) is pumped into the hot section molten salt heat exchanger (3) to absorb and store excess heat; When the exhaust steam in the hot section molten salt heat exchanger (3) is lower than the steam input temperature of the low-pressure cylinder (8), the hot section molten salt heat exchanger (3) is not used to absorb the heat of the reheated steam, but the steam in the auxiliary steam unit (5) is connected to the low-pressure cylinder (8) for steam supplement, and is detected by the seventh temperature detection module (39) to adjust the steam inlet flow of the auxiliary steam unit (5). Finally, the exhaust steam of the intermediate pressure cylinder (9) and the low-pressure cylinder (8) is collected and enters the main steam unit (1), thereby forming a closed-loop control circuit and realizing intelligent detection of the system under low-load operation.

2. A high-temperature molten salt deep peak-shaving heat storage system according to claim 1, characterized in that: A molten salt pump (30) is provided between the cold salt tank (6), the main steam molten salt heat exchanger (2) and the hot section molten salt heat exchanger (3), and the operating temperature of the molten salt pump (30) is set to 280-300°C.

3. A high-temperature molten salt deep peak-shaving heat storage system according to claim 2, characterized in that: Two groups of molten salt pumps (30) are provided, and the input ends of the two groups of molten salt pumps (30) are respectively connected to the cold salt tank (6) through pipelines; The output ends of one group of the molten salt pumps (30) are connected to the feed ports of the main steam molten salt heat exchanger (2) and the hot section molten salt heat exchanger (3) respectively through a main pipeline (28), and the feed end of the main pipeline (28) is provided with a first butterfly valve (26) and a first stop valve (22) in sequence along the flow direction of the molten salt; The output end of another group of molten salt pumps (30) is connected to the discharge end of the first stop valve (22) through an auxiliary pipe (29), and the feed end of the auxiliary pipe (29) is sequentially provided with a second butterfly valve (27) and a second stop valve (23) along the flow direction of the molten salt.

4. A high-temperature molten salt deep peak-shaving heat storage system according to claim 3, characterized in that: The feed ports of the main steam molten salt heat exchanger (2) and the hot section molten salt heat exchanger (3) are respectively provided with electronic gate valves (43); the discharge ports of the main steam molten salt heat exchanger (2) and the hot section molten salt heat exchanger (3) are connected to the hot salt tank (7) through pipelines; and the feed port of the hot salt tank (7) is provided with a two-position three-way pneumatic solenoid valve (31).

5. A high-temperature molten salt deep peak-shaving heat storage system according to claim 3, characterized in that: A first-stage unloading pipeline (41) is provided on the main pipeline (28) between the first butterfly valve (26) and the first stop valve (22), and a third stop valve (24) is provided on the first-stage unloading pipeline (41); A secondary unloading pipe (42) is provided on the auxiliary pipe (29) between the second butterfly valve (27) and the second stop valve (23), and a fourth stop valve (25) is provided on the secondary unloading pipe (42); The other ends of the first-level unloading pipe (41) and the second-level unloading pipe (42) are respectively connected to the cold salt tank (6).

6. A high-temperature molten salt deep peak-shaving heat storage system according to claim 1, characterized in that: The detection unit comprises: a first temperature detection module (33), the first temperature detection module (33) being installed on the primary pipeline (11) and being used to detect the input temperature of steam in the primary pipeline (11); a second temperature detection module (34), the second temperature detection module (34) being installed on the six-stage pipeline (16) and being used to detect the input temperature of steam in the six-stage pipeline (16); a third temperature detection module (35), the third temperature detection module (35) being installed on the secondary pipeline (12) and being used to detect the input temperature of the steam in the sixth-level pipeline (16); a fourth temperature detection module (36), the fourth temperature detection module (36) being installed on the tertiary pipeline (13) and being used to detect the input temperature of the steam in the tertiary pipeline (13); a fifth temperature detection module (37), the fifth temperature detection module (37) being installed on the eight-stage pipeline (18) and being used to detect the input temperature of steam in the eight-stage pipeline (18); a sixth temperature detection module (38) and a seventh temperature detection module (39), the sixth temperature detection module (38) and the seventh temperature detection module (39) being respectively located on both sides of the electronic valve group on the four-stage pipeline (14), the sixth temperature detection module (38) being installed at the steam inlet end of the four-stage pipeline (14), and the seventh temperature detection module (39) being installed at the steam outlet end of the four-stage pipeline (14), for detecting the input temperature of the steam in the four-stage pipeline (14); an eighth temperature detection module (40), the eighth temperature detection module (40) being installed on the ten-stage pipeline (20) and being used to detect the input temperature of steam in the ten-stage pipeline (20); The first temperature detection module (33), the second temperature detection module (34), the third temperature detection module (35), the fourth temperature detection module (36), the fifth temperature detection module (37), the sixth temperature detection module (38), the seventh temperature detection module (39) and the eighth temperature detection module (40) are respectively connected to the controller.

7. A high-temperature molten salt deep peak-shaving heat storage system according to claim 6, characterized in that: The detection unit is provided with at least a temperature sensor, and the test probes of the temperature sensor are respectively placed in the pipelines at each level, for collecting temperature information of the steam in the corresponding pipeline and feeding it back to the controller.

8. The high-temperature molten salt deep peak-shaving heat storage system according to claim 3, characterized in that: A flow detection sensor (32) is provided on the main pipeline (28) at the discharge end of the auxiliary pipeline (29). The flow detection sensor (32) is connected to the controller and is used to detect the transport flow of the molten salt in the main pipeline (28).

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