A steam heated molten salt energy storage system

Abstract

The present application belongs to the technical field of thermal power generation, and particularly relates to a steam heating molten salt energy storage system, which comprises a boiler, a main steam molten salt heat exchanger, a hot section molten salt heat exchanger, a cold reheat steam unit, a reheat steam branch pipeline, a cold tank, a hot tank, a low-pressure cylinder, a medium-pressure cylinder, a high-pressure cylinder and an intelligent diagnosis system; main steam of the boiler is divided into two routes and respectively enters the main steam molten salt heat exchanger to heat molten salt and the high-pressure cylinder to work, reheat steam is divided into two routes and respectively enters the hot section molten salt heat exchanger to heat molten salt and the medium-pressure cylinder to work, and the molten salt is stored in the hot tank after being heated; the intelligent diagnosis system detects equipment parameters through a monitoring unit, combines with a blade vibration condition, and controls the blade vibration within a threshold value through an adjusting unit. The present application can make the low-pressure cylinder normally operate under low load, meet the peak shaving demand of 20% THA of the steam turbine unit, and avoid damage of the steam turbine unit.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of thermal power generation, and particularly relates to a steam heating molten salt energy storage system. BACKGROUND

[0002] Thermal power generating units can provide power supply for power grids and play the role of power support. With the development of society, people's demand for electricity is increasing, and the power system urgently needs large-scale flexible power supply to improve the power supply structure, relieve the system peak load pressure, and solve the new energy consumption capacity.

[0003] At present, the flexibility reconstruction of thermal power generating units is mainly limited by the limited boiler peak shaving depth, insufficient economy and safety of the unit, and the like. The existing flexibility of thermal power generating units is realized by reconstructing the boiler, and the boiler adopts a combined pulverized coal dense and thin separation combustion system to realize 30% THA stable combustion. However, the existing technology cannot meet the 20% THA peak shaving demand of the steam turbine unit, and cannot guarantee the safe and stable operation of the steam turbine at low load, and long-term operation is easy to cause damage to the steam turbine unit. SUMMARY

[0004] The purpose of the present application is to overcome the defects of the prior art and provide a steam heating molten salt energy storage system.

[0005] The present application provides a steam heating molten salt energy storage system,

[0006] including a boiler, a main steam molten salt heat exchanger, a hot section molten salt heat exchanger, a cold reheat steam unit, a reheat steam branch pipeline, a cold tank, a hot tank, a low-pressure cylinder, a medium-pressure cylinder, a high-pressure cylinder and an intelligent diagnosis system;

[0007] The main steam in the boiler enters the main steam molten salt heat exchanger in one way to heat and treat the molten salt, and a first preheating pipeline is arranged in parallel on the main steam in one way, the gas inlet of the first preheating pipeline is connected to the gas outlet end of the main steam in one way, and the gas outlet of the first preheating pipeline is connected to the gas inlet end of the main steam molten salt heat exchanger;

[0008] Another way enters the high-pressure cylinder to do work, the exhaust gas in the main steam molten salt heat exchanger and the high-pressure cylinder is collected and then enters the cold reheat steam unit to form reheat steam, one way of the reheat steam enters the boiler, and the other way of the reheat steam is connected to the gas inlet end of the low-pressure cylinder through the reheat steam branch pipeline, and the exhaust gas in the low-pressure cylinder enters the boiler;

[0009] The reheat steam in the boiler enters the hot section molten salt heat exchanger in one way to heat and treat the molten salt, and a second preheating pipeline and a third preheating pipeline are arranged in parallel on the reheat steam in one way, the gas inlet ends of the second preheating pipeline and the third preheating pipeline are connected to the gas outlet end of the reheat steam, and the gas outlet ends of the second preheating pipeline and the third preheating pipeline are connected to the gas inlet end of the hot section molten salt heat exchanger;

[0010] The reheat steam in the boiler enters the medium pressure cylinder to do work, and the exhaust steam in the hot section molten salt heat exchanger and the exhaust steam in the medium pressure cylinder are combined to enter the low pressure cylinder to do work and then are sent into the boiler;

[0011] The molten salt led out from the cold tank enters the main steam molten salt heat exchanger and the hot section molten salt heat exchanger to be heated, and the heated molten salt is led into the hot tank to be stored, so as to realize heat storage;

[0012] The intelligent diagnosis system is connected with the controller, the monitoring unit, the adjusting unit and the blade vibration detector; the intelligent diagnosis system is respectively used for detecting the steam input temperature and pressure of the main steam molten salt heat exchanger, the hot section molten salt heat exchanger, the low pressure cylinder, the medium pressure cylinder and the high pressure cylinder through the monitoring unit, comparing the temperature and pressure in the low pressure cylinder with the blade vibration condition after detection, and adjusting the blade vibration to be within the set threshold through the adjusting unit after comparison, so as to meet the normal operation of the low pressure cylinder under low load;

[0013] Further, the monitoring unit is installed on the pipeline connected between the main steam outlet end in the boiler and the main steam molten salt heat exchanger and on the pipeline connected between the reheat steam outlet end in the boiler and the hot section molten salt heat exchanger, and is used for monitoring the steam input temperature and pressure of the main steam molten salt heat exchanger, the hot section molten salt heat exchanger, the medium pressure cylinder and the high pressure cylinder; the monitoring unit is also installed at the last stage and the second last stage of the low pressure cylinder, and is used for monitoring the temperature and pressure in the low pressure cylinder,

[0014] The adjusting unit is installed on the first preheating pipeline, the second preheating pipeline and the third preheating pipeline 11, and is used for increasing the temperature of the molten salt in the main steam molten salt heat exchanger and the hot section molten salt heat exchanger; the adjusting unit is installed on the reheat steam branch pipeline, and is used for adjusting the temperature and pressure in the low pressure cylinder to make the blade vibration normal;

[0015] Further, the monitoring unit comprises a temperature sensor and a pressure sensor;

[0016] Further, the adjusting unit comprises a first preheating valve, a second preheating valve, a third preheating valve and a fourth preheating valve; the first preheating valve is installed on the third preheating pipeline, the second preheating valve is installed on the second preheating pipeline, the third preheating valve is installed on the first preheating pipeline, and the fourth preheating valve is installed on the reheat steam branch pipeline,

[0017] The controller is connected with the first preheating valve, the second preheating valve, the third preheating valve, the fourth preheating valve and the electromechanical synchronization module, and is used for controlling the opening angle of the first preheating valve, the second preheating valve, the third preheating valve and the fourth preheating valve;

[0018] Further, two groups of cold salt pumps are arranged between the cold tank and the main steam molten salt heat exchanger and the hot section molten salt heat exchanger, and the working temperature of the cold salt pump is set to 300-350℃;

[0019] Further, the input ends of the two groups of cold salt pumps are connected to the cold tank through pipelines respectively; the output end of one group of cold salt pumps is connected to the feed inlet of the main steam molten salt heat exchanger and the hot section molten salt heat exchanger through a first pipeline, and the feed end of the first pipeline is sequentially provided with a first butterfly valve and a first stop valve along the flow direction of the molten salt, and the group of cold salt pumps is used as a main molten salt pump for normal use;

[0020] The output end of the other group of cold salt pumps is connected to the discharge end of the first stop valve through a second pipeline, and the feed end of the second pipeline is sequentially provided with a second butterfly valve and a second stop valve along the flow direction of the molten salt;

[0021] Further, the first pipeline is connected to a third pipeline, the third pipeline is provided with a third stop valve, the second pipeline is connected to a fourth pipeline, the fourth pipeline is provided with a fourth stop valve, and the other ends of the third pipeline and the fourth pipeline are connected to the cold tank respectively;

[0022] Further, the pipeline connecting the main steam outlet end of the boiler to the inlet end of the main steam molten salt heat exchanger and the pipeline connecting the reheat steam outlet end of the boiler to the inlet end of the hot section molten salt heat exchanger are respectively provided with a solenoid valve and a check valve for controlling the on-off and flow rate of the corresponding pipeline;

[0023] Further, the main steam molten salt heat exchanger and the hot section molten salt heat exchanger are made of SA-240Gr.347H;

[0024] Further, the nozzle of the low-pressure cylinder is made of stainless steel;

[0025] Compared with the prior art, the beneficial effects of the present application are as follows:

[0026] The steam heating molten salt energy storage system of the present application improves the heat storage efficiency of the heat storage system by improving the low-pressure cylinder temperature and the unit start criterion of the deep peak shaving heat storage system, by increasing the bypass of the main steam pipeline and the reheat steam pipeline, by setting the first preheating pipeline, the second preheating pipeline and the third preheating pipeline; the temperature and pressure in the low-pressure cylinder are adjusted by setting the reheat steam branch pipeline to make the blade vibration normal; the intelligent diagnosis system is used to detect the steam input temperature and pressure of the main steam molten salt heat exchanger, the hot section molten salt heat exchanger, the low-pressure cylinder, the medium-pressure cylinder and the high-pressure cylinder through the monitoring unit, and the temperature and pressure in the low-pressure cylinder after detection are compared with the blade vibration condition, and the blade vibration is adjusted within the set threshold value through the adjusting unit after comparison, so that the low-pressure cylinder can normally operate under low load, meet the peak shaving demand of 20% THA of the steam turbine unit performance, and avoid damage to the steam turbine unit caused by long-term operation. BRIEF DESCRIPTION OF DRAWINGS

[0027] The following drawings are only used to illustrate and explain the present application, and are not used to limit the scope of the present application, wherein:

[0028] Fig. 1 The system principle diagram of the steam heated molten salt energy storage system of the present application;

[0029] Fig. 2 The working principle diagram of the intelligent diagnosis system of the present application;

[0030] In the figure: 1-boiler, 2-high pressure cylinder, 3-medium pressure cylinder, 4-low pressure cylinder, 5-cold reheat steam unit, 6-main steam molten salt heat exchanger, 7-hot section molten salt heat exchanger, 8-cold tank, 9-hot tank, 10-second preheating pipeline, 11-third preheating pipeline, 13-first preheating pipeline, 14-reheat steam branch pipeline, 15-second preheating valve, 20-second preheating valve, 21-first preheating valve, 22-fourth preheating valve, 23-third preheating valve, 24-first pipeline, 25-first stop valve, 26-first butterfly valve, 27-second pipeline, 28-second butterfly valve, 29-second stop valve, 30-cold salt pump, 31-third pipeline, 32-fourth pipeline. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme, design method and advantages of the present application more clear and obvious, the present application is further described in detail below by specific embodiments combined with the drawings. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0032] As shown in Figs. 1-2 , the present application provides a steam heated molten salt energy storage system,

[0033] including a boiler 1, a main steam molten salt heat exchanger 6, a hot section molten salt heat exchanger 7, a cold reheat steam unit 5, a reheat steam branch pipeline 14, a cold tank 8, a hot tank 9, a low pressure cylinder 4, a medium pressure cylinder 3, a high pressure cylinder 2 and an intelligent diagnosis system;

[0034] The main steam in the boiler 1 enters the main steam molten salt heat exchanger 6 for heating treatment, and a first preheating pipeline 13 is arranged in parallel on the main steam, and the air inlet of the first preheating pipeline 13 is connected to the air outlet end of the main steam, and the air outlet of the first preheating pipeline 13 is connected to the air inlet end of the main steam molten salt heat exchanger 6;

[0035] Another road enters the high pressure cylinder 2 to do work, the exhaust gas in the main steam molten salt heat exchanger 6 and the high pressure cylinder 2 is collected and then enters the cold reheat steam unit 5 to form reheat steam, one road of the reheat steam enters the boiler 1, and the other road of the reheat steam is connected to the air inlet end of the low pressure cylinder 4 through the reheat steam branch pipeline 14, and the exhaust gas in the low pressure cylinder 4 enters the boiler 1;

[0036] The reheat steam in the boiler 1 is heated by the hot section molten salt heat exchanger 7, and the second preheating pipeline 10 and the third preheating pipeline 11 are connected in parallel to the reheat steam, the gas inlet ends of the second preheating pipeline 10 and the third preheating pipeline 11 are connected to the gas outlet end of the reheat steam, and the gas outlet ends of the second preheating pipeline 10 and the third preheating pipeline 11 are connected to the gas inlet end of the hot section molten salt heat exchanger 7;

[0037] The reheat steam in the boiler 1 is heated by the hot section molten salt heat exchanger 7, and the second preheating pipeline 10 and the third preheating pipeline 11 are connected in parallel to the reheat steam, the gas inlet ends of the second preheating pipeline 10 and the third preheating pipeline 11 are connected to the gas outlet end of the reheat steam, and the gas outlet ends of the second preheating pipeline 10 and the third preheating pipeline 11 are connected to the gas inlet end of the hot section molten salt heat exchanger 7;

[0038] The molten salt discharged from the cold tank 8 is heated by the main steam molten salt heat exchanger 6 and the hot section molten salt heat exchanger 7, and then is introduced into the hot tank 9 for storage, so as to realize heat storage;

[0039] The intelligent diagnosis system is connected with the controller, the monitoring unit, the adjusting unit and the blade vibration detector; the intelligent diagnosis system is used for detecting the steam input temperature and pressure of the main steam molten salt heat exchanger 6, the hot section molten salt heat exchanger 7, the low-pressure cylinder 4, the medium-pressure cylinder 3 and the high-pressure cylinder 2 through the monitoring unit; after detection, the temperature and pressure in the low-pressure cylinder 4 are compared with the blade vibration condition, and then the blade vibration is adjusted within the set threshold value through the adjusting unit, so as to meet the normal operation of the low-pressure cylinder under low load;

[0040] It should be noted that the blade vibration detector is a non-contact detector, and the blade vibration detector is installed near the blade of the steam turbine;

[0041] Further, the monitoring unit is installed on the pipeline connecting the main steam gas outlet end in the boiler 1 and the gas inlet end of the main steam molten salt heat exchanger 6 and on the pipeline connecting the reheat steam gas outlet end in the boiler 1 and the gas inlet end of the hot section molten salt heat exchanger 7, and is used for monitoring the steam input temperature and pressure of the main steam molten salt heat exchanger 6, the hot section molten salt heat exchanger 7, the medium-pressure cylinder 3 and the high-pressure cylinder 2; the monitoring unit is also installed at the last stage and the second last stage of the low-pressure cylinder 4, and is used for monitoring the temperature and pressure in the low-pressure cylinder 4,

[0042] The adjusting unit is installed on the first preheating pipeline 13, the second preheating pipeline 10 and the third preheating pipeline 11, and is used for improving the molten salt temperature in the main steam molten salt heat exchanger 6 and the hot section molten salt heat exchanger 7, so as to improve the heat storage efficiency of the system; the adjusting unit is installed on the reheat steam branch pipeline 14, and is used for adjusting the temperature and pressure in the low-pressure cylinder 4 to make the blade vibration normal;

[0043] Further, the monitoring unit comprises a temperature sensor and a pressure sensor;

[0044] It should be noted that the temperature sensor is an infrared non-contact sensor; wherein, two temperature sensors are installed at the last stage of the low-pressure cylinder, and four temperature sensors are installed at the penultimate stage;

[0045] Further, the adjusting unit comprises a first preheating valve 21, a second preheating valve 20, a third preheating valve 23, a fourth preheating valve 22, the first preheating valve 21 is installed on the third preheating pipeline 11, the second preheating valve 20 is installed on the second preheating pipeline 10, the third preheating valve 23 is installed on the first preheating pipeline 13, and the fourth preheating valve 22 is installed on the reheat steam branch pipeline 14,

[0046] The controller is connected with the first preheating valve 21, the second preheating valve 20, the third preheating valve 23, the fourth preheating valve 22 and the electromechanical synchronization module respectively, and is used for controlling the opening angle of the preheating valve.

[0047] It should be noted that in the embodiment, the steam temperature in the boiler 1 is greater than the steam temperature in the cold reheat steam unit 5.

[0048] Further, two groups of cold salt pumps 30 are arranged between the cold tank 8 and the main steam molten salt heat exchanger 6 and the hot section molten salt heat exchanger 7, and the working temperature of the cold salt pump 30 is set to 300-350℃.

[0049] Further, the input ends of the two groups of cold salt pumps 30 are connected to the cold tank 8 through pipelines respectively; the output end of one group of cold salt pumps 30 is connected to the feed inlet of the main steam molten salt heat exchanger 6 and the hot section molten salt heat exchanger 7 through a first pipeline 24 respectively, and the feed end of the first pipeline 24 is sequentially provided with a first butterfly valve 26 and a first stop valve 25 along the flow direction of the molten salt, so that the group of cold salt pumps 30 is used as a main molten salt pump for normal use.

[0050] The output end of the other group of cold salt pumps 30 is connected to the discharge end of the first stop valve 25 through a second pipeline 27, and the feed end of the second pipeline 27 is sequentially provided with a second butterfly valve 28 and a second stop valve 29 along the flow direction of the molten salt, so that the group of cold salt pumps 30 is used as a standby molten salt pump, and when the main molten salt pump is damaged, the standby molten salt pump is started to maintain the normal operation of the heat storage system.

[0051] Further, a third pipeline 31 is connected to the first pipeline 24, and a third stop valve is installed on the third pipeline 31; a fourth pipeline 32 is connected to the second pipeline 27, and a fourth stop valve is installed on the fourth pipeline 32; the other ends of the third pipeline 31 and the fourth pipeline 32 are respectively connected to the cold tank 8, so that the residual molten salt in the first pipeline 24 and the second pipeline 27 can be discharged after the cold salt pump 30 stops working, avoiding corrosion of the molten salt to the pipeline;

[0052] Further, an electromagnetic valve and a check valve are respectively installed on the pipeline connecting the main steam outlet end of the boiler 1 with the main steam molten salt heat exchanger 6 and the pipeline connecting the reheat steam outlet end of the boiler 1 with the hot section molten salt heat exchanger 7, for controlling the opening and closing and the flow rate of the corresponding pipeline;

[0053] Further, the material of the main steam molten salt heat exchanger 6 and the hot section molten salt heat exchanger 7 is SA-240Gr.347H;

[0054] The operation mode of the steam heated molten salt energy storage system is as follows:

[0055] The main steam in the boiler 1 enters the main steam molten salt heat exchanger 6 for heating treatment, and a first preheating pipeline 13 is connected in parallel to the main steam pipeline, the inlet of the first preheating pipeline 13 is connected with the outlet of the main steam pipeline, and the outlet of the first preheating pipeline 13 is connected with the inlet of the main steam molten salt heat exchanger 6;

[0056] The other part of the main steam enters the high pressure cylinder 2 for work, the exhaust steam in the main steam molten salt heat exchanger 6 and the high pressure cylinder 2 is collected and then enters the cold reheat steam unit 5 to form reheat steam, one part of the reheat steam enters the boiler 1, and the other part of the reheat steam is connected to the inlet of the low pressure cylinder 4 through a reheat steam branch pipeline 14, and the exhaust steam in the low pressure cylinder 4 enters the boiler 1;

[0057] The reheat steam in the boiler 1 enters the hot section molten salt heat exchanger 7 for heating treatment, and a second preheating pipeline 10 and a third preheating pipeline 11 are connected in parallel to the reheat steam pipeline, the inlets of the second preheating pipeline 10 and the third preheating pipeline 11 are connected with the outlet of the reheat steam pipeline, and the outlets of the second preheating pipeline 10 and the third preheating pipeline 11 are connected with the inlet of the hot section molten salt heat exchanger 7;

[0058] The other part of the reheat steam in the boiler 1 enters the medium pressure cylinder 3 for work, the exhaust steam in the hot section molten salt heat exchanger 7 and the exhaust steam in the medium pressure cylinder 3 are collected and then enter the low pressure cylinder 4 for work and are sent into the boiler 1;

[0059] The molten salt led out from the cold tank 8 enters the main steam molten salt heat exchanger 6 and the hot section molten salt heat exchanger 7 for heating, and the heated molten salt is led into the hot tank 9 for storage, and finally the heat energy storage is realized;

[0060] The intelligent diagnosis system is connected with the controller, the monitoring unit, the adjusting unit and the blade vibration detector; the intelligent diagnosis system is respectively used for detecting the steam input temperature and pressure of the main steam molten salt heat exchanger 6, the hot section molten salt heat exchanger 7, the low-pressure cylinder 4, the medium-pressure cylinder 3 and the high-pressure cylinder 2 through the monitoring unit, comparing the temperature and pressure in the low-pressure cylinder 4 with the detected blade vibration condition after detection, and adjusting the blade vibration to be within the set threshold through the adjusting unit after comparison, so that the low-pressure cylinder can normally operate under low load.

[0061] It should be noted that in the deep peak regulation stage, the cold salt pump 30 collects the low-temperature molten salt (about 290C°) into the steam-molten salt heat exchanger of the steam side energy storage system, exchanges heat with the main steam molten salt heat exchanger 6 and the hot section molten salt heat exchanger 7, and the temperature is increased to about 530-560C°, and returns to the hot tank from the flow annular distribution pipe in the cold tank;

[0062] Among them, in order to adapt to the temperature margin and starting criterion of the improved deep peak regulation heat storage system, the low-pressure cylinder adopts a stainless steel nozzle, the low-pressure cylinder is sprayed on the positive and negative secondary last stage blades, and two temperature sensors are installed on the last stage of the low-pressure cylinder and four temperature sensors are installed on the secondary last stage;

[0063] By increasing the bypass of the main steam pipeline and the hot reheat steam pipeline, setting the first preheating pipeline 13, the second preheating pipeline 10 and the third preheating pipeline 11, the heat storage efficiency of the heat storage system is improved; on the reheat steam branch pipeline 14, the temperature and pressure in the low-pressure cylinder 4 are adjusted to make the blade vibration normal;

[0064] An intelligent diagnosis system is provided, which is connected with the controller, the monitoring unit, the adjusting unit and the blade vibration detector; the intelligent diagnosis system is respectively used for detecting the steam input temperature and pressure of the main steam molten salt heat exchanger 6, the hot section molten salt heat exchanger 7, the low-pressure cylinder 4, the medium-pressure cylinder 3 and the high-pressure cylinder 2 through the monitoring unit, comparing the temperature and pressure in the low-pressure cylinder 4 with the detected blade vibration condition after detection, and adjusting the blade vibration to be within the set threshold through the adjusting unit after comparison, so that the low-pressure cylinder can normally operate under low load.

[0065] The above has described the embodiments of the present application, the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles, practical applications or technical improvements in the market of the embodiments, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A steam-heated molten salt energy storage system, characterized in that, It includes a boiler (1), a main steam molten salt heat exchanger (6), a hot section molten salt heat exchanger (7), a cold reheat steam unit (5), a reheat steam branch pipeline (14), a cold tank (8), a hot tank (9), a low-pressure cylinder (4), a medium-pressure cylinder (3), a high-pressure cylinder (2), and an intelligent diagnostic system; The main steam in the boiler (1) enters the main steam molten salt heat exchanger (6) to heat the molten salt. A first preheating pipe (13) is connected in parallel along the main steam path. The inlet of the first preheating pipe (13) is connected to the outlet of the main steam path, and the outlet of the first preheating pipe (13) is connected to the inlet of the main steam molten salt heat exchanger (6). The other path enters the high-pressure cylinder (2) to do work. The exhaust steam in the main steam molten salt heat exchanger (6) and the high-pressure cylinder (2) is collected and enters the cold reheat steam unit (5) to form reheat steam. One path of the reheat steam enters the boiler (1), and the other outlet of the reheat steam is connected to the inlet of the low-pressure cylinder (4) through the reheat steam branch pipe (14). The exhaust steam in the low-pressure cylinder (4) enters the boiler (1). The reheat steam in the boiler (1) enters the hot section molten salt heat exchanger (7) to heat the molten salt. The reheat steam is connected in parallel with a second preheating pipe (10) and a third preheating pipe (11). The inlet of the second preheating pipe (10) and the third preheating pipe (11) connected in parallel is connected to the outlet of the reheat steam. The outlet of the second preheating pipe (10) and the third preheating pipe (11) is connected to the inlet of the hot section molten salt heat exchanger (7). The reheat steam in the boiler (1) enters the intermediate pressure cylinder (3) to do work. The exhaust steam in the hot section molten salt heat exchanger (7) and the exhaust steam in the intermediate pressure cylinder (3) are combined and enter the low pressure cylinder (4) to do work before being sent to the boiler (1). Molten salt extracted from the cold tank (8) enters the main steam molten salt heat exchanger (6) and the hot section molten salt heat exchanger (7) for heating, and the heated molten salt is introduced into the hot tank (9) for storage, thereby realizing thermal energy storage; The intelligent diagnostic system includes a controller connected to a monitoring unit, an adjustment unit, and a blade vibration detector. The intelligent diagnostic system is used to detect the steam input temperature and pressure of the main steam molten salt heat exchanger (6), the hot section molten salt heat exchanger (7), the low-pressure cylinder (4), the medium-pressure cylinder (3), and the high-pressure cylinder (2) through the monitoring unit. After detection, the temperature and pressure in the low-pressure cylinder (4) are compared with the detected blade vibration status. After comparison, the blade vibration is adjusted by the adjustment unit to keep it within a set threshold, thereby ensuring that the low-pressure cylinder can operate normally under low load.

2. The steam-heated molten salt energy storage system according to claim 1, characterized in that, The monitoring unit is installed on the pipe connecting the main steam outlet of the boiler (1) to the inlet of the main steam molten salt heat exchanger (6) and on the pipe connecting the reheat steam outlet of the boiler (1) to the inlet of the hot section molten salt heat exchanger (7). It is used to monitor the steam input temperature and pressure of the main steam molten salt heat exchanger (6), the hot section molten salt heat exchanger (7), the intermediate pressure cylinder (3), and the high pressure cylinder (2). The monitoring unit is also installed in the last stage and the second last stage of the low pressure cylinder (4) to monitor the temperature and pressure inside the low pressure cylinder (4). The regulating unit is installed on the first preheating pipe (13), the second preheating pipe (10), and the third preheating pipe (11) to increase the molten salt temperature in the main steam molten salt heat exchanger (6) and the hot section molten salt heat exchanger (7); the regulating unit is installed on the reheat steam branch pipe (14) to regulate the temperature and pressure in the low-pressure cylinder so that the blades vibrate normally.

3. The steam-heated molten salt energy storage system according to claim 1, characterized in that, The monitoring unit includes a temperature sensor and a pressure sensor.

4. The steam-heated molten salt energy storage system according to claim 1, characterized in that, The regulating unit includes a first preheating valve (21), a second preheating valve (20), a third preheating valve (23), and a fourth preheating valve (22). The first preheating valve (21) is installed on the third preheating pipe (11), the second preheating valve (20) is installed on the second preheating pipe (10), the third preheating valve (23) is installed on the first preheating pipe (13), and the fourth preheating valve (22) is installed on the reheat steam branch pipe (14). The controller is connected to the first preheating valve (21), the second preheating valve (20), the third preheating valve (23), the fourth preheating valve (22) and the electromechanical synchronization module respectively, and is used to control and adjust the opening angle of the first preheating valve (21), the second preheating valve (20), the third preheating valve (23) and the fourth preheating valve (22).

5. The steam-heated molten salt energy storage system according to claim 1, characterized in that, Two sets of cold salt pumps (30) are provided between the cold tank (8) and the main steam molten salt heat exchanger (6) and the hot section molten salt heat exchanger (7), and the operating temperature of the cold salt pumps (30) is set to 300-350℃.

6. The steam-heated molten salt energy storage system according to claim 5, characterized in that, The input ends of the two sets of cold salt pumps (30) are respectively connected to the cold tank (8) through pipelines; the output end of one set of cold salt pumps (30) is connected to the feed inlet of the main steam molten salt heat exchanger (6) and the hot section molten salt heat exchanger (7) through the first pipeline (24). The feed end of the first pipeline (24) is provided with a first butterfly valve (26) and a first shut-off valve (25) in sequence along the flow direction of the molten salt. The set of cold salt pumps (30) is used as the main molten salt pump for normal use. The output end of another set of cold salt pumps (30) is connected to the discharge end of the first shut-off valve (25) through the second pipe (27). The feed end of the second pipe (27) is provided with a second butterfly valve (28) and a second shut-off valve (29) in sequence along the flow direction of the molten salt.

7. A steam-heated molten salt energy storage system according to claim 6, characterized in that, The first pipe (24) is connected to the third pipe (31), and the third pipe (31) is equipped with a third shut-off valve. The second pipe (27) is connected to the fourth pipe (32), and the fourth pipe (32) is equipped with a fourth shut-off valve. The other ends of the third pipe (31) and the fourth pipe (32) are respectively connected to the cold tank (8).

8. The steam-heated molten salt energy storage system according to claim 1, characterized in that, Solenoid valves and check valves are installed on the pipes connecting the main steam outlet of the boiler (1) to the inlet of the main steam molten salt heat exchanger (6) and on the pipes connecting the reheat steam outlet of the boiler (1) to the inlet of the hot section molten salt heat exchanger (7), respectively, to control the opening and closing of the corresponding pipes and the flow rate.

9. A steam-heated molten salt energy storage system according to claim 1, characterized in that, The main steam molten salt heat exchanger (6) and the hot section molten salt heat exchanger (7) are made of SA-240Gr.347H material.

10. A steam-heated molten salt energy storage system according to claim 1, characterized in that, The nozzle of the low-pressure cylinder (4) is made of stainless steel.

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