Purging and flushing method for pipeline of thermal power steam extraction fused salt energy storage system

Abstract

The invention relates to the field of pipeline cleaning, in particular to a thermal power steam extraction molten salt energy storage system pipeline purging and flushing method, and a heat storage and release system of the energy storage system covers heat storage molten salt, a steam extraction-heat storage and molten salt-steam generation SGS system. Three targeted purging and flushing schemes are adopted according to the difference of the system operation stage, the pipeline characteristics, the working condition and the air source condition, and when fused salt and water are put into an SGS system and steam is produced by the SGS system, impurities are purged by the SGS system; the molten salt heat storage part system is connected with a temporary pipeline by means of industrial steam for purging under specific conditions; and when the unit is started, the main water supply pipeline of the # 1 unit is used for flushing the specific pipeline. According to the method, pipeline impurities can be effectively removed, smooth heat storage and heat release processes are guaranteed, the heat exchange efficiency is improved, energy loss is reduced, and the performance of an energy storage system is enhanced. Meanwhile, a clear purging range and a reasonable process are achieved, equipment damage is avoided, the purging efficiency is improved, the service life of the equipment is prolonged, the fault probability is reduced, and the economical efficiency and reliability of the thermal power generating unit are improved.

Description

Technical Field

[0001] The present invention relates to the field of pipeline cleaning, and particularly to a method for purging and flushing pipelines in a thermal power extraction steam molten salt energy storage system. Background Art

[0002] The thermal power extraction steam molten salt energy storage system is an energy storage system applied to thermal power units. Its heat storage and release system includes a molten salt heat storage system, an extraction steam - heat storage system, and a molten salt - steam generation SGS system. By using ternary molten salt as the heat storage medium, it stores heat during low - load periods of thermal power units and releases heat during high - load periods, achieving deep peak shaving of thermal power units and improving energy utilization efficiency. In the thermal power extraction steam molten salt energy storage system, traditional pipeline purging and flushing techniques often lack pertinence, and do not fully consider the differences in different operating stages of the system, the characteristics of each part of the pipeline, system operating conditions, and gas source conditions. Moreover, a single purging method does not consider the changes in system operating conditions and gas source conditions, resulting in poor purging effects, inability to flexibly select a suitable purging method, incomplete cleaning of key pipelines, and affecting the heat storage effect.

[0003] Therefore, it is necessary to propose a method for purging and flushing pipelines in a thermal power extraction steam molten salt energy storage system to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for purging and flushing pipelines in a thermal power extraction steam molten salt energy storage system to solve the problem of poor purging effect caused by a single purging method that does not fully consider the differences in different operating stages of the system, the characteristics of each part of the pipeline, system operating conditions, and gas source conditions.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: A method for purging and flushing pipelines in a thermal power extraction steam molten salt energy storage system. The thermal power extraction steam molten salt energy storage system includes a heat storage and release system, and the heat storage and release system includes a molten salt heat storage system, an extraction steam - heat storage system, and a molten salt - steam generation SGS system. According to the different operating stages of the thermal power extraction steam molten salt energy storage system, the characteristics of each part of the pipeline, system operating conditions, and gas source conditions, different pipelines in the system are respectively purged and flushed in a targeted manner. The following are three purging and flushing schemes: When the molten salt - steam generation SGS system inputs molten salt and feed water and can generate self - produced steam, use the self - produced steam as the purging steam source to blow out the sundries generated by heat release and steam production to the interface of the main engine cold reheat pipeline. The interface of the main engine cold reheat pipeline is temporarily disconnected, a temporary purging pipeline is connected, and the interface is restored after purging. When the molten salt heat storage part of the system is installed and completed, and the molten salt - steam generation SGS system is not running or cannot provide a purging steam source, set up a temporary pipeline at the coal feeder layer to connect industrial steam and the hot reheat steam pipeline, connect a temporary pipeline from the flow orifice plate of the hot reheat pipeline to connect the main steam pipeline and the cold reheat pipeline, and set corresponding manual valves. During the unit startup, when the main feed water pipe pressure of Unit 1 is 2 MPa and the temperature is 120 °C, open the main feed water pipe valve of Unit 1 to allow water to first flush the pipe from the zero-meter of the molten salt plant to the outlet pipe of the heat storage return pump, then flush the pipe from the condensate tank to the inlet pipe of the heat storage return pump and the recirculation pipe of the heat storage return pump, and finally flush the steam-water pipes of molten salt heat exchangers C1 to C3.

[0006] Preferably, the pressure of the self-generated steam is 3.5 - 4.0 MPa and the temperature is lower than 350 °C.

[0007] Preferably, before purging the molten salt-steam generation SGS system, check the sealing of the interface between the temporary purging pipe and the host cold reheat pipe.

[0008] Preferably, the purging line for purging and flushing the molten salt-steam generation SGS system is that debris is purged and discharged successively through the evaporator, steam drum, superheater, temporary pipe, exhaust header pipe, temporary blowing valve 1, target plate, and silencer. All reasonably installed drain pipes in the blowing pipe system are drained to the trench.

[0009] Preferably, in the purging plan for the molten salt heat storage part system, the purging scope includes: the pipe from the main steam of Unit 1 to the inlet of molten salt heat exchanger A, the pipe from the reheated steam of Unit 1 to the inlet of molten salt heat exchanger B, the high-pressure steam inlet header pipe of the pressure matcher, and the exhaust header pipe of the pressure matcher to the cold reheat pipe of Unit 1.

[0010] Preferably, in the purging plan for the molten salt heat storage part system, the purging scope does not include: each high-pressure steam inlet branch pipe of the pressure matcher, each low-pressure steam inlet header pipe and branch pipes of the pressure matcher, each exhaust branch pipe of the pressure matcher, the pipeline of molten salt heat exchangers C1, C2, drain tank, molten salt heat exchanger C3, condensate tank, heat storage return pump A, heat storage return pump B, before the inlet of the high-pressure heater outlet pipeline, temporary pipe, and temporary drain valve.

[0011] Preferably, in the pipeline of molten salt heat exchangers C1, C2, drain tank, molten salt heat exchanger C3, condensate tank, heat storage return pump A, heat storage return pump B, before the inlet of the high-pressure heater outlet pipeline, temporary pipe, and temporary drain valve, when purging and flushing this section of the pipeline, it is necessary to use drain water for water flushing when the extraction-heat storage system is put into operation.

[0012] Preferably, when purging the molten salt heat storage part system, the material of the temporary pipe connecting the industrial steam and the hot reheat steam pipe is selected to be heat-resistant, high-pressure-resistant and corrosion-resistant.

[0013] Preferably, the heat storage process of the molten salt heat storage system and the extraction - heat storage system is as follows: When the unit needs deep peak shaving, the extracted main steam is cooled by the A molten salt heat exchanger of the molten salt heat storage system. Then, part of the steam is mixed with the reheated hot - section steam cooled by the B molten salt heat exchanger and then returned to the reheated cold - section steam system after steam distribution. The remaining steam is cooled to the sub - cooled water state through the C1 heat exchanger to the C3 heat exchanger and then returned to the power plant thermodynamic system. The extracted reheated hot - section steam is cooled by the B molten salt heat exchanger and then is ejected to the reheated cold - section steam by the main steam through the pressure matcher. After the molten salt absorbs the heat released by the main steam and the reheated steam from the low - temperature tank through the main steam, the reheated hot - section steam, and the molten salt heat exchanger, it is stored in the high - temperature molten salt tank.

[0014] Preferably, the heat - release process of the molten salt - steam generation SGS system is as follows: Feed water enters the molten salt - steam generation SGS system and is gradually evaporated after being heated by the molten salt through the pre - heater, evaporator, and steam drum. After reaching the appropriate outlet temperature by being continuously heated by the high - temperature molten salt in the super - heater, it returns to the reheated cold - section. The high - temperature molten salt returns to the low - temperature molten salt tank after releasing heat through the super - heater, evaporator, and pre - heater.

[0015] The technical effects and advantages of the present invention are as follows: 1. The three purging and flushing schemes are formulated according to different operating stages and working conditions of the system. The SGS system uses self - generated steam for purging. Some parts of the molten salt heat storage system use industrial steam supply under specific conditions. The zero - meter pipeline uses the main feed - water pipeline for flushing during unit startup. This flexible purging method can effectively clean different pipeline characteristics and steam source conditions at each stage of system construction, commissioning, and operation, ensuring the effectiveness and safety of pipeline cleaning work.

[0016] 2. Targeted purging and flushing can effectively remove impurities such as rust and welding slag in the pipeline, avoiding their impact on the flow of steam, molten salt, and water, and ensuring the smoothness of the heat storage and heat - release processes. The removal of impurities can also improve the heat - exchange efficiency, making the heat transfer between the molten salt and steam, and the molten salt and feed water more efficient, reducing energy loss, and improving the performance of the entire energy - storage system.

[0017] 3. Clearly defining the purging scope and non - purging scope of the purging scheme can not only ensure the effective cleaning of key pipelines but also avoid unnecessary damage to pipelines and equipment with complex and delicate structures. For parts that are not suitable for purging, subsequent water flushing is carried out using drain water. This phased and targeted purging process improves the overall purging efficiency. Brief Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the purging structure of the molten salt - steam generation SGS system of the present invention.

[0019] Figure 2 It is a schematic diagram of the purging structure of the molten salt heat storage part system of the present invention.

[0020] Figure 3 This is a schematic diagram of the flushing structure of the pipeline from the zero-meter level of the molten salt plant of the present invention to the outlet of the heat storage return water pump. Specific embodiments

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] The present invention provides a method for purging and flushing the pipelines of a thermal power extraction steam molten salt energy storage system as shown in Figures 1-3 The thermal power extraction steam molten salt energy storage system includes a heat storage and release system, which includes a molten salt heat storage system, a steam extraction - heat storage system, and a molten salt - steam generation SGS system. According to the different operating stages of the thermal power extraction steam molten salt energy storage system, the characteristics of each part of the pipeline, the system working conditions, and the gas source conditions, targeted purging and flushing are carried out on different pipelines in the system. The following are three purging and flushing schemes: When the molten salt - steam generation SGS system inputs molten salt and feed water and can generate self - produced steam, use the self - produced steam as the purging gas source to blow out the sundries generated during the heat - release steam - generation process to the interface of the main engine cold reheat pipeline. The interface of the main engine cold reheat pipeline is temporarily disconnected, and a temporary purging pipeline is connected. After purging, the interface is restored. When the molten salt - steam generation SGS system inputs molten salt and feed water and has the condition to generate steam, start purging. First, temporarily disconnect the interface of the main engine cold reheat pipeline and connect a temporary purging pipeline. Use the self - produced steam of the SGS system, whose pressure is 3.5 - 4.0 MPa and temperature is lower than 350 °C, to purge the sundries generated during the heat - release steam - generation process in equipment such as the evaporator, steam drum, and superheater according to the line of evaporator, steam drum, superheater, temporary pipe, exhaust header pipe, temporary blowing valve 1, target plate, and silencer. The drain of the blow - pipe system is discharged to the trench through a reasonably installed pipeline. After purging, restore the interface of the main engine cold reheat pipeline.

[0023] When the molten salt heat storage part of the system is installed and the molten salt - steam generation SGS system is not operating or unable to provide a purging gas source, set up a temporary pipeline at the coal feeder layer to connect industrial steam and the hot reheat steam pipeline, connect a temporary pipeline from the flow orifice plate of the hot reheat pipeline to connect the main steam pipeline and the cold reheat pipeline, and set corresponding manual valves; It is implemented when the molten salt thermal energy storage part of the system is installed, while the molten salt-steam generation SGS system is not running or unable to provide a purging steam source. On the coal feeder floor, select materials that are resistant to high temperature, high pressure, and corrosion to fabricate temporary pipelines, and connect the industrial steam supply to the hot reheat steam pipeline. Connect the temporary pipelines from near the flow orifice plate of the hot reheat pipeline to the main steam pipeline and the cold reheat pipeline respectively, and install the corresponding manual valves. Open the manual valves, and use the industrial steam supply pipeline as a buffer vessel to provide stable purging steam to backwash the pipeline from the main steam of Unit 1 to the inlet of Molten Salt Heat Exchanger A, the reheat steam of Unit 1 to the inlet of Molten Salt Heat Exchanger B, the high-pressure steam inlet header of the pressure matcher, and the exhaust header of the pressure matcher to the cold reheat pipeline of Unit 1. The relevant branch pipes of each pressure matcher and some pipelines such as Molten Salt Heat Exchanger C1 to Molten Salt Heat Exchanger C3 are not within the scope of this purging.

[0024] This purging plan utilizes the role of the industrial steam supply pipeline within the company, which is equivalent to a large buffer vessel, to ensure the continuity of the purging steam and the purging flow rate. The selected temperature and pressure meet the purging requirements, and the pipeline section from the heat storage and heat exchange to the cold reheat pipe is backwashed.

[0025] During the unit startup period, when the main feed water pipeline pressure of Unit 1 is 2 MPa and the temperature is 120 °C, open the valve of the main feed water pipeline of Unit 1 to first flush the pipeline from the zero meter of the molten salt workshop to the outlet of the heat storage return water pump, then flush the pipeline from the condensate tank to the inlet of the heat storage return water pump and the recirculation pipeline of the heat storage return water pump, and finally flush the steam-water pipelines of Molten Salt Heat Exchanger C1 to Molten Salt Heat Exchanger C3; In the embodiment of the present invention, through targeted purging and flushing, debris in the pipeline is removed, avoiding the influence of impurities on the heat transfer efficiency, blocking the pipeline, or damaging the equipment during the system operation. During the purging of the SGS system, debris in equipment such as the evaporator is removed to ensure the smooth generation and transportation of steam; the purging of the molten salt thermal energy storage part of the system ensures the cleanliness of the heat exchange pipelines and improves the heat storage effect; the flushing of the relevant pipelines at zero meter ensures the smoothness of the water circulation pipelines and maintains the stable operation of the system.

[0026] The three purging and flushing plans are formulated according to different operation stages and working conditions of the system. The SGS system uses the self-generated steam for purging, the molten salt thermal energy storage part of the system uses the industrial steam supply under specific conditions, and the pipelines at zero meter use the main feed water pipeline for flushing during the unit startup, flexibly coping with various situations during the construction, commissioning, and operation of the system, and ensuring the effectiveness and safety of the pipeline cleaning work.

[0027] Regular purging and flushing can reduce the wear and corrosion of pipelines and equipment, extend the service life of equipment, reduce the probability of equipment failures, reduce the maintenance and replacement costs due to equipment damage, and improve the economy and reliability of thermal power units.

[0028] Further, the pressure of the self-generated steam is 3.5 - 4.0 MPa and the temperature is lower than 350 °C.

[0029] Further, before purging the molten salt - steam generation SGS system, check the sealing performance of the interface between the temporary purging pipeline and the host cold reheat pipeline.

[0030] Further, the purging line for purging and flushing the molten salt - steam generation SGS system is that debris is purged and discharged in sequence through the evaporator, steam drum, superheater, temporary pipe, exhaust main pipe, temporary blowing valve 1, target plate, and silencer. All reasonably installed drain pipelines in the blowing pipe system are drained to the trench.

[0031] In the embodiment of the present invention, limiting the pressure of the self-generated steam to 3.5 - 4.0 MPa and the temperature to be lower than 350 °C can ensure the safety and efficiency of the purging process. This parameter range ensures that the steam has sufficient power to effectively blow out the debris in the pipeline, achieving a good purging effect. At the same time, reasonable temperature and pressure conditions can prevent high parameters from causing thermal shock, deformation, or damage to the pipeline and equipment, avoiding safety accidents caused by abnormal steam parameters, and ensuring the safe and stable operation of the system equipment during the entire purging process.

[0032] Before purging the molten salt - steam generation SGS system, checking the sealing performance of the interface between the temporary purging pipeline and the host cold reheat pipeline can effectively prevent steam leakage. If the interface is not tightly sealed, steam leakage will not only reduce the purging pressure, affect the purging effect, and cause debris to not be completely removed, but also may cause harm to the surrounding personnel and equipment. Through the sealing performance check, the sealing problem can be discovered and solved in advance, ensuring the smooth progress of the purging work and avoiding safety hazards and economic losses caused by leakage.

[0033] The clear purging line ensures the planned discharge of debris, avoiding the residue of debris in the system or the blockage of other parts. The reasonably installed drain pipelines drain the condensate in the blowing pipe system to the trench, which can prevent the accumulation of condensate in the pipeline. If the condensate accumulates, it may cause water hammer phenomenon, damaging the pipeline and equipment; the accumulated water may also affect the steam flow and reduce the purging effect. The standardized purging line and condensate management ensure the normal operation of the system and reduce the risk of equipment failure.

[0034] Further, in the purging plan for the molten salt heat storage part of the system, the purging scope includes: the pipeline from the main steam of Unit 1 to the inlet of Molten Salt Heat Exchanger A, the pipeline from the reheated steam of Unit 1 to the inlet of Molten Salt Heat Exchanger B, the high-pressure steam inlet main pipe of the pressure matcher, and the exhaust main pipe of the pressure matcher to the cold reheat pipeline of Unit 1.

[0035] Blow the main steam inlet pipeline of Unit 1 to the molten salt heat exchanger A and the reheated steam inlet pipeline of Unit 1 to the molten salt heat exchanger B, which can effectively remove the impurities remaining in these pipelines during installation or maintenance, such as rust, welding slag, etc. If these impurities enter the molten salt heat exchanger, it will affect the heat exchange efficiency, reduce the heat storage capacity, and even block the pipeline, affecting the normal operation of the system.

[0036] Furthermore, in the system blow - through plan for the molten salt heat storage part, the blow - through scope does not include: the high - pressure steam inlet branch pipes of each pressure matcher, the low - pressure steam inlet main pipes and branch pipes of each pressure matcher, the exhaust branch pipes of each pressure matcher, the pipeline molten salt heat exchangers C1, molten salt heat exchanger C2, drain tank, molten salt heat exchanger C3, condensate tank, heat storage return pump A, heat storage return pump B, before the inlet of the high - pressure heater outlet pipeline, temporary pipe, and temporary drain valve.

[0037] The branch pipe diameters of each pressure matcher are relatively small, the structure is complex, and the internal structures of some equipment such as molten salt heat exchangers and drain tanks are delicate. If blown through at this time, it may cause pipeline deformation and damage to internal components of the equipment due to excessive impact force of the blowing medium, affecting the normal performance and service life of the equipment.

[0038] Furthermore, in the pipeline of the molten salt heat exchanger C1, molten salt heat exchanger C2, drain tank, molten salt heat exchanger C3, condensate tank, heat storage return pump A, heat storage return pump B, before the inlet of the high - pressure heater outlet pipeline, temporary pipe, and temporary drain valve, when flushing this section of the pipeline during blow - through, it needs to be flushed with drain water when the extraction - heat storage system is put into operation.

[0039] Furthermore, when blowing through the molten salt heat storage part of the system, the material of the temporary pipeline connecting the industrial steam and the hot reheat steam pipeline is selected to be heat - resistant, high - pressure - resistant, and corrosion - resistant.

[0040] Furthermore, the heat storage process of the molten salt heat storage system and the extraction - heat storage system is as follows: When the unit needs deep peak shaving, the extracted main steam is cooled by the A molten salt heat exchanger of the molten salt heat storage system, then part of the steam is mixed with the reheated hot - section steam cooled by the B molten salt heat exchanger and then returned to the cold - section reheated steam system after steam distribution. The remaining steam is cooled to the sub - cooled water state through heat exchangers C1 to C3 and then returned to the power plant thermodynamic system. The extracted reheated hot - section steam is cooled by the B molten salt heat exchanger and then is ejected to the cold - section reheated steam by the main steam through the pressure matcher. The molten salt absorbs the heat released by the main steam and reheated steam from the low - temperature tank through the main steam, reheated hot - section steam, and molten salt heat exchanger, and then is stored in the high - temperature molten salt tank.

[0041] Further, the heat release process of the molten salt-steam generation SGS system is as follows: Feed water enters the molten salt-steam generation SGS system, passes through the preheater, evaporator and steam drum, is gradually evaporated after being heated by the molten salt, and then returns to the cold reheat section after reaching the appropriate outlet temperature by being continuously heated by the high-temperature molten salt in the superheater. The high-temperature molten salt returns to the low-temperature molten salt tank after releasing heat through the superheater, evaporator and preheater.

[0042] A large amount of steam, molten salt and water flow are involved in the heat storage and heat release processes. If there are impurities in the pipeline, such as rust, welding slag, etc., it may hinder the normal flow of the medium and affect the smoothness of the entire process. Through the purging and flushing scheme, these impurities can be effectively removed to ensure that media such as main steam, reheated steam, molten salt and feed water can flow smoothly in the system, and guarantee the normal progress of the heat storage and heat release processes.

[0043] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection required by the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for purging and flushing pipelines of a thermal power extraction molten salt energy storage system. The thermal power extraction molten salt energy storage system includes a heat storage and release system, and the heat storage and release system includes a molten salt heat storage system, a steam extraction - heat storage system, and a molten salt - steam generation SGS system. It is characterized in that, During different operation stages of the thermal power extraction steam molten salt energy storage system, considering the characteristics of each part of the pipeline, system conditions and gas source conditions, targeted purging and flushing are carried out for different pipelines in the system. The following are three purging and flushing schemes: When molten salt and feed water are input into the molten salt - steam generation SGS system and self - generated steam can be produced, use the self - generated steam as the purging steam source to blow out the sundries generating heat and steam to the interface of the main engine cold reheat pipeline. The interface of the main engine cold reheat pipeline is temporarily disconnected, a temporary purging pipeline is connected, and the interface is restored after purging. When the molten salt heat storage part of the system is installed and the molten salt - steam generation SGS system is not operating or unable to provide a purging steam source, set up a temporary pipeline at the coal feeder layer to connect industrial steam and the hot reheat steam pipeline, connect a temporary pipeline from the flow orifice plate of the hot reheat pipeline to connect the main steam pipeline and the cold reheat pipeline, and set corresponding manual valves. During the unit startup period, when the pressure of the main feed water pipeline of Unit 1 is 2 MPa and the temperature is 120 °C, open the valve of the main feed water pipeline of Unit 1 to first flush the pipeline from the zero - meter of the molten salt plant to the outlet of the heat storage return water pump, then flush the pipeline from the condensate tank to the inlet of the heat storage return water pump and the recirculation pipeline of the heat storage return water pump, and finally flush the steam - water pipeline from molten salt heat exchanger C1 to molten salt heat exchanger C3.

2. A method for purging and flushing pipelines of a thermal power extraction steam molten salt energy storage system according to claim 1, characterized in that: The pressure of the self - generated steam is 3.5 - 4.0 MPa and the temperature is lower than 350 °C.

3. A method for purging and flushing pipelines of a thermal power extraction steam molten salt energy storage system according to claim 1, characterized in that: Before purging the molten salt - steam generation SGS system, check the sealing performance of the interface between the temporary purging pipeline and the main engine cold reheat pipeline.

4. A method for purging and flushing pipelines of a thermal power extraction steam molten salt energy storage system according to claim 1, characterized in that: The purging line of the molten salt - steam generation SGS system purging and flushing is that sundries are purged and discharged successively through the evaporator, steam drum, superheater, temporary pipe, exhaust header pipe, temporary blowing valve 1, target plate, and silencer. All reasonably installed drain pipelines in the blow - pipe system are drained to the trench.

5. A method for purging and flushing pipelines of a thermal power extraction steam molten salt energy storage system according to claim 1, characterized in that, In the purging scheme of the molten salt heat storage part of the system, the purging scope includes: the pipeline from the main steam of Unit 1 to the inlet of molten salt heat exchanger A, the pipeline from the reheated steam of Unit 1 to the inlet of molten salt heat exchanger B, the high - pressure inlet header pipe of the pressure matcher, and the exhaust header pipe of the pressure matcher to the cold reheat pipeline of Unit 1.

6. A method for purging and flushing pipelines of a thermal power extraction steam molten salt energy storage system according to claim 1, characterized in that, In the purging scheme of the molten salt heat storage part of the system, the purging scope does not include: each high - pressure inlet branch pipe of the pressure matcher, each low - pressure inlet header pipe and branch pipe of the pressure matcher, each exhaust branch pipe of the pressure matcher, the pipeline of molten salt heat exchanger C1, molten salt heat exchanger C2, drain tank, molten salt heat exchanger C3, condensate tank, heat storage return water pump A, heat storage return water pump B, before the inlet of the high - pressure heater outlet pipeline, temporary pipe, and temporary drain valve.

7. A method for purging and flushing pipelines of a thermal power extraction steam molten salt energy storage system according to claim 6, characterized in that: In the pipeline of molten salt heat exchanger C1, molten salt heat exchanger C2, drain tank, molten salt heat exchanger C3, condensate tank, heat storage return water pump A, heat storage return water pump B, before the inlet of the high - pressure heater outlet pipeline, temporary pipe, and temporary drain valve, when purging and flushing this section of the pipeline, it is necessary to use drain water for water flushing when the extraction - heat storage system is put into operation.

8. A method for purging and flushing pipelines of a thermal power extraction steam molten salt energy storage system according to claim 1, characterized in that: When purging the molten salt heat storage part of the system, the material of the temporary pipeline connecting industrial steam and the hot reheat steam pipeline is selected to be heat - resistant, high - pressure - resistant and corrosion - resistant.

9. A method for purging and flushing pipelines of a thermal power extraction steam molten salt energy storage system according to claim 1, characterized in that, The heat storage process of the molten salt heat storage system and the extraction-thermal energy storage system is as follows: When the unit needs deep peak shaving, the extracted main steam is cooled by the A molten salt heat exchanger of the molten salt heat storage system, and then part of the steam is mixed with the reheated steam in the hot reheat section that has been cooled by the B molten salt heat exchanger and then returned to the cold reheat section steam system after steam distribution. The remaining steam is cooled to the subcooled water state through the C1 heat exchanger to the C3 heat exchanger and then returned to the power plant thermal system. The extracted reheated steam in the hot reheat section is cooled by the B molten salt heat exchanger and then is ejected to the cold reheat section steam by the main steam through the pressure matcher. After the molten salt absorbs the heat released by the main steam and the reheated steam from the low-temperature tank through the main steam, the reheated steam in the hot reheat section, and the molten salt heat exchanger, it is stored in the high-temperature molten salt tank.

10. A method for purging and flushing pipelines of a thermal power extraction steam molten salt energy storage system according to claim 1, characterized in that, The heat release process of the molten salt-steam generation SGS system is as follows: Feed water enters the molten salt-steam generation SGS system, passes through the preheater, evaporator, and steam drum, is gradually evaporated by being heated by the molten salt, and after being continuously heated by the high-temperature molten salt in the superheater to reach the appropriate outlet temperature, it returns to the cold reheat section. After the high-temperature molten salt releases heat through the superheater, evaporator, and preheater, it returns to the low-temperature molten salt tank.

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