Coal-fired power generation system based on high-pressure cylinder zero output and steam extraction heat storage and operation method

Abstract

The application discloses a coal-fired power generation system and an operation method based on zero output of a high-pressure cylinder and steam extraction heat storage, and the system comprises a coal-fired power generation system and a molten salt heat storage system; when the system deeply regulates peak, a small amount of cooling steam is introduced into the high-pressure cylinder to realize zero output, high-temperature cold molten salt and medium-temperature cold molten salt absorb heat of a main steam superheating section and heat of a reheated steam superheating section and latent heat section respectively, and the heated molten salt is stored in a high-temperature hot salt tank and a medium-temperature hot salt tank respectively, and the coal-fired power generation system realizes reduction of output electric power under the condition that the boiler is stable; when the system needs to rapidly increase load, the medium-temperature hot molten salt firstly heats feed water passing through a feed water diversion valve, a part of the heated feed water flows to a boiler feed water inlet, another part of the heated feed water is heated by the high-temperature hot molten salt into superheated steam, and then the superheated steam is combined with hot section reheated steam to enter a steam turbine to do work, and output electric power of the coal-fired power generation system is rapidly increased.

Description

Technical Field

[0001] This invention relates to the field of thermal power generation technology, specifically to a coal-fired power generation system and its operation method based on zero output of a high-pressure cylinder and extraction steam heat storage. Background Technology

[0002] With the rapid increase in the proportion of new energy units such as wind power and photovoltaic power in the power system, their strong time-varying characteristics have brought severe challenges to the frequency regulation, power balance and voltage stability of the power grid. At present, coal-fired power generation, as the "ballast" of the power system's power supply, needs to undertake a large number of peak shaving and frequency regulation tasks to support the grid connection of a high proportion of new energy sources. Therefore, it is urgent to improve its operational flexibility.

[0003] However, the potential to improve the operational flexibility of coal-fired power generation systems by altering their thermal configuration or adjusting control strategies has been largely exhausted. Against this backdrop, molten salt thermal storage systems, by achieving thermoelectric decoupling, can overcome the limitations of traditional coal-fired power generation systems, reduce the output power of the boiler at its minimum stable combustion load, and increase the unit's load change rate, making it one of the effective ways to improve the load change performance of coal-fired power generation units. However, most existing technologies, due to complex safety constraints, struggle to balance operational flexibility and efficient utilization of molten salt thermal storage systems. For example, while using main steam as a heat source to heat molten salt can achieve a high equivalent cycle efficiency, the reduction in boiler output power at the minimum stable combustion load is limited by reheater overheating limitations. Conversely, using reheat steam as a heat source significantly reduces the equivalent cycle efficiency, but is still limited by the turbine's minimum flow rate, making it difficult to reduce the minimum load rate below 20%. Therefore, in order to further reduce the output power of coal-fired power generation under the minimum stable combustion load of the boiler and maintain a high equivalent cycle efficiency, it is necessary to carry out targeted thermal system modifications to avoid complex safety constraints and achieve efficient and flexible operation of coal-fired power generation systems with integrated molten salt thermal storage systems. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a coal-fired power generation system and its operation method based on zero output of a high-pressure cylinder and extraction steam thermal storage. This system includes a coal-fired power generation system and a molten salt thermal storage system. During deep peak shaving, a small amount of cooling steam is introduced into the high-pressure cylinder to achieve zero output. High-temperature and medium-temperature molten salts absorb heat from the superheated section of the main steam and the superheated and latent heat sections of the reheated steam, respectively. The heated molten salts are stored in high-temperature and medium-temperature hot salt tanks, respectively. Under stable boiler combustion conditions, the coal-fired power generation system achieves a reduction in output power. When the system needs to rapidly increase the load, the medium-temperature hot molten salt first heats the feedwater passing through the feedwater diversion valve. Part of the heated feedwater flows to the boiler feedwater inlet, while the other part is heated by the high-temperature hot molten salt into superheated steam, which then merges with the reheated steam in the hot section before entering the turbine to perform work, thus rapidly increasing the output power of the coal-fired power generation system.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A coal-fired power generation system based on zero output of a high-pressure cylinder and extraction steam thermal storage includes a coal-fired power generation system and a molten salt thermal storage system; The coal-fired power generation system includes a boiler 1, a high-pressure cylinder 2, an intermediate-pressure cylinder 3, a low-pressure cylinder 4, a generator 5, a condenser 6, a condensate pump 7, a low-pressure regenerator group 8, a deaerator 9, a feedwater pump 10, a high-pressure regenerator group 11, a main steam valve 12, and an intermediate regulating valve 13. The main steam outlet of boiler 1 is connected to the steam inlet of main steam valve 12, the steam outlet of main steam valve 12 is connected to the steam inlet of high-pressure cylinder 2, the exhaust outlet of high-pressure cylinder 2 is connected to the cold section reheat steam inlet of boiler 1, the hot section reheat steam outlet of boiler 1 is connected to the steam inlet of intermediate regulating valve 13, the steam outlet of intermediate regulating valve 13 is connected to the steam inlet of intermediate-pressure cylinder 3, the exhaust outlet of intermediate-pressure cylinder 3 is connected to the steam inlet of low-pressure cylinder 4, and the exhaust outlet of low-pressure cylinder 4 is connected to the steam inlet of condenser 6. The condensate outlet of condenser 6 is connected to the inlet of condensate pump 7. The condensate outlet of condensate pump 7 is connected to the condensate inlet of low-pressure regenerator group 8. The condensate outlet of low-pressure regenerator group 8 is connected to the condensate inlet of deaerator 9. The saturated water outlet of deaerator 9 is connected to the inlet of feedwater pump 10. The outlet of feedwater pump 10 is connected to the feedwater inlet of high-pressure regenerator group 11. The feedwater outlet of high-pressure regenerator group 11 is connected to the feedwater inlet of boiler 1. The steam extraction outlet of high-pressure cylinder 2 is connected to the steam inlet of high-pressure regenerator group 11. The steam extraction outlet of intermediate-pressure cylinder 3 is connected to the steam inlet of deaerator 9. The steam extraction outlet of low-pressure cylinder 4 is connected to the steam inlet of low-pressure regenerator group 8. High-pressure cylinder 2, intermediate-pressure cylinder 3, and low-pressure cylinder 4 drive generator 5 through a rotating shaft to output electrical power. The technical upgrade to achieve zero output of the high-pressure cylinder 2 in the coal-fired power generation system includes: adding a first steam shut-off valve 14 to the connecting pipe between the exhaust port of the high-pressure cylinder 2 and the reheat steam inlet of the cold section of the boiler 1; adding a steam pipe to the exhaust port of the high-pressure cylinder 2, which is connected to the steam inlet of the condenser 6 through the high-pressure cylinder exhaust valve 15; adding a second steam shut-off valve group 16 to the connecting pipe between the extraction steam outlet of the high-pressure cylinder 2 and the steam inlet of the high-pressure regenerator group 11; and adding a steam pipe to the reheat steam outlet of the hot section of the boiler 1, which is connected to the steam inlet of the high-pressure cylinder 2 through the main reheat steam connecting valve 17. The molten salt side of the molten salt thermal storage system includes a high-temperature cold salt tank 18, a high-temperature cold salt pump 19, a high-temperature cold salt valve 20, a main steam molten salt heat exchanger 21, a high-temperature hot salt tank 22, a medium-temperature cold salt tank 25, a medium-temperature cold salt pump 26, a medium-temperature cold salt valve 27, a reheat steam molten salt heat exchanger 28, a medium-temperature hot salt tank 29, a medium-temperature hot salt pump 32, a medium-temperature hot salt valve 33, a molten salt feedwater heat exchanger 34, a high-temperature hot salt pump 36, a high-temperature hot salt valve 37, and a molten salt steam generator. 38; In the thermal storage circuit, the molten salt outlet of the high-temperature cold salt tank 18 is connected to the molten salt inlet of the high-temperature cold salt pump 19, the molten salt outlet of the high-temperature cold salt pump 19 is connected to the molten salt inlet of the high-temperature cold salt valve 20, the molten salt outlet of the high-temperature cold salt valve 20 is connected to the molten salt inlet of the main steam molten salt heat exchanger 21, the molten salt outlet of the main steam molten salt heat exchanger 21 is connected to the molten salt inlet of the high-temperature hot salt tank 22, the molten salt outlet of the medium-temperature cold salt tank 25 is connected to the molten salt inlet of the medium-temperature cold salt pump 26, and the medium-temperature cold salt pump 2... The molten salt outlet of valve 6 is connected to the molten salt inlet of medium-temperature cold salt valve 27. The molten salt outlet of medium-temperature cold salt valve 27 is connected to the molten salt inlet of reheat steam molten salt heat exchanger 28. The molten salt outlet of reheat steam molten salt heat exchanger 28 is connected to the molten salt inlet of medium-temperature hot salt tank 29. In the heat release circuit, the molten salt outlet of high-temperature hot salt tank 22 is connected to the molten salt inlet of high-temperature hot salt pump 36. The molten salt outlet of high-temperature hot salt pump 36 is connected to the molten salt inlet of high-temperature hot salt valve 37. The molten salt outlet of high-temperature hot salt valve 37 is connected to the molten salt inlet of the medium-temperature hot salt tank 29. The molten salt inlet of the salt steam generator 38 is connected, the molten salt outlet of the molten salt steam generator 38 is connected to the molten salt inlet of the high-temperature cold salt tank 18, the molten salt outlet of the medium-temperature hot salt tank 29 is connected to the molten salt inlet of the medium-temperature hot salt pump 32, the molten salt outlet of the medium-temperature hot salt pump 32 is connected to the molten salt inlet of the medium-temperature hot salt valve 33, the molten salt outlet of the medium-temperature hot salt valve 33 is connected to the molten salt inlet of the molten salt feed water heat exchanger 34, and the molten salt outlet of the molten salt feed water heat exchanger 34 is connected to the molten salt inlet of the medium-temperature cold salt tank 25. The connection relationship between the steam-water side of the molten salt thermal storage system and the coal-fired power generation system is as follows: The main steam outlet of boiler 1 is connected to the steam inlet of main steam diversion valve 23. The steam outlet of main steam diversion valve 23 is connected to the steam inlet of main steam molten salt heat exchanger 21. The steam outlet of main steam molten salt heat exchanger 21 is divided into two paths: one path is connected to the reheat steam inlet of the cold section of boiler 1, and the other path is connected to the steam inlet of high-pressure regenerator group steam control valve group 24. The steam outlet of high-pressure regenerator group steam control valve group 24 is connected to the steam inlet of high-pressure regenerator group 11. The reheat steam outlet of the hot section of boiler 1 is connected to the steam inlet of reheat steam diversion valve 30. The steam outlet of reheat steam diversion valve 30 is connected to the steam inlet of reheat steam molten salt heat exchanger 28. The water outlet of reheat steam molten salt heat exchanger 28 is connected to the hot side water inlet of feedwater preheater 31. The hot side water outlet of feedwater preheater 31 is connected to the low-pressure regenerator group. The feedwater inlet of feedwater preheater 31 is connected to the feedwater outlet of feedwater pump 10, and the cold-side water outlet of feedwater preheater 31 is connected to the feedwater inlet of high-pressure regenerator group 11. The cold-side water outlet of feedwater preheater 31 is also connected to the feedwater inlet of feedwater diversion valve 35. The feedwater outlet of feedwater diversion valve 35 is connected to the feedwater inlet of molten salt feedwater heat exchanger 34. The feedwater outlet of molten salt feedwater heat exchanger 34 is divided into two paths: one path is connected to the feedwater inlet of boiler 1, and the other path is connected to the feedwater inlet of molten salt steam generator diversion valve 39. The feedwater outlet of molten salt steam generator diversion valve 39 is connected to the feedwater inlet of molten salt steam generator 38. The steam outlet of molten salt steam generator 38 is connected to the steam inlet of supplementary steam regulating valve 40. The steam outlet of supplementary steam regulating valve 40 is connected to the reheat steam outlet of hot section of boiler 1.

[0006] The high-pressure regenerator group 11, deaerator 9 and low-pressure regenerator group 8 in the coal-fired power generation system are determined according to their specific number of stages and type based on the existing configuration of the coal-fired power generation system; when the high-pressure cylinder 2 is in zero-output condition, the heating steam source of the high-pressure regenerator group 11 corresponding to the original high-pressure cylinder 2 steam extraction is switched to the steam after the main steam heat exchange.

[0007] The measures to ensure safe operation of the high-pressure cylinder under zero-output conditions are as follows: First, adjust the main reheat steam connecting valve 17 to control the pressure and flow rate of the cooling steam entering the high-pressure cylinder 2; Second, dynamically adjust the opening of the high-pressure cylinder exhaust valve 15 to match the vacuum degree of the condenser 6; Third, install a pre-spray water desuperheating device in the pipeline section before the cooling steam enters the high-pressure cylinder 2, and adjust the water spray desuperheating according to the monitoring values ​​of the steam temperature at the inlet and outlet of the high-pressure cylinder 2.

[0008] The operating parameters of the coal-fired power generation system must meet the following constraints: the boiler 1 is operating within the safe and stable operating boundary and meets the environmental emission indicators; the exhaust steam temperature of the high-pressure cylinder 2 and the low-pressure cylinder 4 is controlled within the design allowable range; the axial thrust of the high-pressure cylinder 2 and the medium-pressure cylinder 3 is controlled within the thrust design allowable range of the matching thrust bearing; during deep peak shaving, the deaerator 9 does not experience self-boiling.

[0009] The operating parameters of the molten salt thermal storage system must meet the following constraints: the main steam molten salt heat exchanger 21 is a counter-flow shell-and-tube heat exchanger, and the heat exchange temperature difference must be above 10℃; the molten salt temperature in the high-temperature cold salt tank 18 must be above 20℃ higher than the molten salt temperature in the medium-temperature hot salt tank 29; the reheat steam molten salt heat exchanger 28 is a counter-flow shell-and-tube heat exchanger, and the heat exchange pinch point temperature must be above 5℃; the molten salt temperature in the medium-temperature hot salt tank 29 is above 5℃ higher than the outlet feedwater temperature of the high-pressure regenerator group 11 under the rated load of the coal-fired power generation system; and the molten salt temperature in the medium-temperature cold salt tank 25 is above 5℃ higher than the outlet feedwater temperature of the feedwater pump 10 under the rated load of the coal-fired power generation system.

[0010] Measures to ensure the normal operation of the molten salt thermal storage system include: during deep peak shaving, coordinating and controlling the operating status of condensate pump 7 and feedwater pump 10, and the opening of main steam diversion valve 23 and reheat steam diversion valve 30 to ensure that the molten salt temperature in high-temperature cold salt tank 18, high-temperature hot salt tank 22, medium-temperature cold salt tank 25 and medium-temperature hot salt tank 29 is within the required range; during the heat release phase of the molten salt thermal storage system, coordinating and controlling the operating status of high-temperature hot salt pump 36 and medium-temperature hot salt pump 32, and the opening of feedwater diversion valve 35, molten salt steam generator diversion valve 39, high-temperature hot salt valve 37 and medium-temperature hot salt valve 33 to ensure that the heat exchange pinch point temperature in molten salt steam generator 38 is higher than 5℃.

[0011] An operation method for a coal-fired power generation system based on zero output of a high-pressure cylinder and extraction steam thermal storage is as follows: 1) When the coal-fired power generation system requires deep peak shaving, close the main steam valve 12, the first steam shut-off valve 14, and the second steam shut-off valve group 16; open the high-pressure cylinder exhaust valve 15 and the main reheat steam connecting valve 17. A small amount of reheat steam enters the high-pressure cylinder 2 as cooling steam and flows to the condenser 6, with the high-pressure cylinder in a zero-output state; open the main steam diversion valve 23, the reheat steam diversion valve 30, and the high-pressure regenerator group steam control valve group 24. After all the main steam releases superheated heat in the main steam molten salt heat exchanger 21, it is divided into two paths: one path flows to the cold section reheat steam inlet of boiler 1, and the other path flows to the high-pressure regenerator after being regulated by the high-pressure regenerator group steam control valve group 24. At the steam inlet of unit 11, a large amount of hot-section reheat steam releases heat from the superheated and latent heat sections in the reheat steam molten salt heat exchanger 28, and then flows sequentially through the feedwater preheater 31 and the low-pressure regenerator group 8, reducing the output power of generator 5. On the molten salt side, the molten salt in the high-temperature cold salt tank 18 flows sequentially through the high-temperature cold salt pump 19 and the high-temperature cold salt valve 20, and after absorbing heat from the superheated section of the main steam in the main steam molten salt heat exchanger 21, it flows to the high-temperature hot salt tank 22. The molten salt in the medium-temperature cold salt tank 25 flows sequentially through the medium-temperature cold salt pump 26 and the medium-temperature cold salt valve 27, and after absorbing heat from the superheated and latent heat sections of the hot-section reheat steam in the reheat steam molten salt heat exchanger 28, it flows to the medium-temperature hot salt tank 29. 2) When the coal-fired power generation system needs to rapidly increase the load, the feedwater diversion valve 35 and the molten salt steam generator diversion valve 39 are opened. The feedwater enters the molten salt feedwater heat exchanger 34 and absorbs heat before being divided into two paths: one path flows to the feedwater inlet of boiler 1; the other path enters the molten salt steam generator 38 after passing through the molten salt steam generator diversion valve 39 and absorbs heat to become superheated steam. After being regulated by the supplementary steam regulating valve 40, it merges with the hot section reheat steam and enters the turbine to do work, increasing the output power of generator 5. On the molten salt side, the medium-temperature hot salt in the medium-temperature hot salt tank 29 flows sequentially through the medium-temperature hot salt pump 32 and the medium-temperature hot salt valve 33 to preheat the feedwater in the molten salt feedwater heat exchanger 34. The high-temperature hot salt in the high-temperature hot salt tank 22 flows sequentially through the high-temperature hot salt pump 36 and the high-temperature hot salt valve 37 to heat the diverted feedwater in the molten salt steam generator 38 to generate superheated steam. 3) When the coal-fired power generation system does not require deep peak shaving and rapid load increase, the heat storage circuit and heat release circuit of the molten salt thermal storage system are in thermal standby mode, and the coal-fired power generation system is in normal operating condition.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention integrates high-pressure cylinder zero-output technology and molten salt thermal storage system, and adopts the method of full extraction of main steam and large-scale extraction of hot section reheat steam to significantly reduce the lower limit of unit output, achieve zero output of high-pressure cylinder, and at the same time ensure stable boiler combustion, hydrodynamic safety and pollutant discharge in compliance with standards. (2) The added molten salt thermal storage system can be modularly arranged and has strong applicability. It only needs to be connected to the existing system via bypass pipes and standard valve groups, and the corresponding thermal storage capacity should be configured according to the renovation requirements. It is applicable to both condensing units and cogeneration systems. (3) During the deep peak shaving stage of the coal-fired power generation system, the molten salt thermal storage system can achieve thermal storage by absorbing steam heat, which can assist the coal-fired power generation system in participating in peak shaving and frequency regulation, so that the coal-fired power generation system still has strong grid auxiliary service capabilities under extremely low load conditions; during the stage of rapid load increase of the coal-fired power generation system, the molten salt thermal storage system can significantly improve the unit load change rate and regulation accuracy by heating feedwater to release heat. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the system of the present invention. Detailed Implementation

[0014] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0015] A coal-fired power generation system based on zero output of a high-pressure cylinder and extraction steam thermal storage includes a coal-fired power generation system and a molten salt thermal storage system; The coal-fired power generation system includes a boiler 1, a high-pressure cylinder 2, an intermediate-pressure cylinder 3, a low-pressure cylinder 4, a generator 5, a condenser 6, a condensate pump 7, a low-pressure regenerator group 8, a deaerator 9, a feedwater pump 10, a high-pressure regenerator group 11, a main steam valve 12, and an intermediate regulating valve 13. The main steam outlet of boiler 1 is connected to the steam inlet of main steam valve 12, the steam outlet of main steam valve 12 is connected to the steam inlet of high-pressure cylinder 2, the exhaust outlet of high-pressure cylinder 2 is connected to the cold section reheat steam inlet of boiler 1, the hot section reheat steam outlet of boiler 1 is connected to the steam inlet of intermediate regulating valve 13, the steam outlet of intermediate regulating valve 13 is connected to the steam inlet of intermediate-pressure cylinder 3, the exhaust outlet of intermediate-pressure cylinder 3 is connected to the steam inlet of low-pressure cylinder 4, and the exhaust outlet of low-pressure cylinder 4 is connected to the steam inlet of condenser 6. The condensate outlet of condenser 6 is connected to the inlet of condensate pump 7. The condensate outlet of condensate pump 7 is connected to the condensate inlet of low-pressure regenerator group 8. The condensate outlet of low-pressure regenerator group 8 is connected to the condensate inlet of deaerator 9. The saturated water outlet of deaerator 9 is connected to the inlet of feedwater pump 10. The outlet of feedwater pump 10 is connected to the feedwater inlet of high-pressure regenerator group 11. The feedwater outlet of high-pressure regenerator group 11 is connected to the feedwater inlet of boiler 1. The steam extraction outlet of high-pressure cylinder 2 is connected to the steam inlet of high-pressure regenerator group 11. The steam extraction outlet of intermediate-pressure cylinder 3 is connected to the steam inlet of deaerator 9. The steam extraction outlet of low-pressure cylinder 4 is connected to the steam inlet of low-pressure regenerator group 8. High-pressure cylinder 2, intermediate-pressure cylinder 3, and low-pressure cylinder 4 drive generator 5 through a rotating shaft to output electrical power. The technical modification to achieve zero output of the high-pressure cylinder 2 in the coal-fired power generation system includes: adding a first steam shut-off valve 14 to the connecting pipe between the exhaust port of the high-pressure cylinder 2 and the reheat steam inlet of the cold section of the boiler 1; adding a steam pipe to the exhaust port of the high-pressure cylinder 2, which is connected to the steam inlet of the condenser 6 through the high-pressure cylinder exhaust valve 15; adding a second steam shut-off valve group 16 to the connecting pipe between the extraction steam outlet of the high-pressure cylinder 2 and the steam inlet of the high-pressure regenerator group 11; and adding a steam pipe to the reheat steam outlet of the hot section of the boiler 1, which is connected to the steam inlet of the high-pressure cylinder 2 through the main reheat steam connecting valve 17. The advantage is that by adding pipes and valve groups, the steam flow rate entering the high-pressure cylinder 2 can be greatly reduced, thereby reducing the shaft power transmitted from the high-pressure cylinder 2 to the generator 5 through the rotating shaft, and achieving a significant reduction in the power output of the generator 5. The molten salt side of the molten salt thermal storage system includes a high-temperature cold salt tank 18, a high-temperature cold salt pump 19, a high-temperature cold salt valve 20, a main steam molten salt heat exchanger 21, a high-temperature hot salt tank 22, a medium-temperature cold salt tank 25, a medium-temperature cold salt pump 26, a medium-temperature cold salt valve 27, a reheat steam molten salt heat exchanger 28, a medium-temperature hot salt tank 29, a medium-temperature hot salt pump 32, a medium-temperature hot salt valve 33, a molten salt feedwater heat exchanger 34, a high-temperature hot salt pump 36, a high-temperature hot salt valve 37, and a molten salt steam generator. 38; In the thermal storage circuit, the molten salt outlet of the high-temperature cold salt tank 18 is connected to the molten salt inlet of the high-temperature cold salt pump 19, the molten salt outlet of the high-temperature cold salt pump 19 is connected to the molten salt inlet of the high-temperature cold salt valve 20, the molten salt outlet of the high-temperature cold salt valve 20 is connected to the molten salt inlet of the main steam molten salt heat exchanger 21, the molten salt outlet of the main steam molten salt heat exchanger 21 is connected to the molten salt inlet of the high-temperature hot salt tank 22, the molten salt outlet of the medium-temperature cold salt tank 25 is connected to the molten salt inlet of the medium-temperature cold salt pump 26, and the medium-temperature cold salt pump 2... The molten salt outlet of valve 6 is connected to the molten salt inlet of medium-temperature cold salt valve 27. The molten salt outlet of medium-temperature cold salt valve 27 is connected to the molten salt inlet of reheat steam molten salt heat exchanger 28. The molten salt outlet of reheat steam molten salt heat exchanger 28 is connected to the molten salt inlet of medium-temperature hot salt tank 29. In the heat release circuit, the molten salt outlet of high-temperature hot salt tank 22 is connected to the molten salt inlet of high-temperature hot salt pump 36. The molten salt outlet of high-temperature hot salt pump 36 is connected to the molten salt inlet of high-temperature hot salt valve 37. The molten salt outlet of high-temperature hot salt valve 37 is connected to the molten salt inlet of the medium-temperature hot salt tank 29. The molten salt inlet of the salt steam generator 38 is connected, the molten salt outlet of the molten salt steam generator 38 is connected to the molten salt inlet of the high-temperature cold salt tank 18, the molten salt outlet of the medium-temperature hot salt tank 29 is connected to the molten salt inlet of the medium-temperature hot salt pump 32, the molten salt outlet of the medium-temperature hot salt pump 32 is connected to the molten salt inlet of the medium-temperature hot salt valve 33, the molten salt outlet of the medium-temperature hot salt valve 33 is connected to the molten salt inlet of the molten salt feed water heat exchanger 34, and the molten salt outlet of the molten salt feed water heat exchanger 34 is connected to the molten salt inlet of the medium-temperature cold salt tank 25. The connection relationship between the steam-water side of the molten salt thermal storage system and the coal-fired power generation system is as follows: The main steam outlet of boiler 1 is connected to the steam inlet of main steam diversion valve 23. The steam outlet of main steam diversion valve 23 is connected to the steam inlet of main steam molten salt heat exchanger 21. The steam outlet of main steam molten salt heat exchanger 21 is divided into two paths: one path is connected to the reheat steam inlet of the cold section of boiler 1, and the other path is connected to the steam inlet of high-pressure regenerator group steam control valve group 24. The steam outlet of high-pressure regenerator group steam control valve group 24 is connected to the steam inlet of high-pressure regenerator group 11. The reheat steam outlet of the hot section of boiler 1 is connected to the steam inlet of reheat steam diversion valve 30. The steam outlet of reheat steam diversion valve 30 is connected to the steam inlet of reheat steam molten salt heat exchanger 28. The water outlet of reheat steam molten salt heat exchanger 28 is connected to the hot side water inlet of feedwater preheater 31. The hot side water outlet of feedwater preheater 31 is connected to the drain inlet of low-pressure regenerator group 8. The cold side water inlet of feedwater preheater 31 is connected to the feedwater outlet of feedwater pump 10. The cold-side water outlet of the feedwater preheater 31 is connected to the feedwater inlet of the high-pressure regenerator group 11. The advantage is that it makes full use of the heat energy carried by the steam. The heat of the high-temperature and medium-temperature sections of the steam is stored in the molten salt heat storage system, and the heat of the low-temperature section of the steam preheats the feedwater and condensate, realizing efficient energy utilization. The cold-side water outlet of the feedwater preheater 31 is also connected to the feedwater inlet of the feedwater diversion valve 35. The feedwater outlet of the feedwater diversion valve 35 is connected to the feedwater inlet of the molten salt feedwater heat exchanger 34. The feedwater outlet of the molten salt feedwater heat exchanger 34 is divided into two paths. One path is connected to the feedwater inlet of boiler 1, and the other path is connected to the feedwater inlet of the molten salt steam generator diversion valve 39. The feedwater outlet of the molten salt steam generator diversion valve 39 is connected to the feedwater inlet of the molten salt steam generator 38. The steam outlet of the molten salt steam generator 38 is connected to the steam inlet of the supplementary steam regulating valve 40. The steam outlet of the supplementary steam regulating valve 40 is connected to the reheat steam outlet of the hot section of boiler 1. The advantage lies in the fact that the configuration of step heating the feedwater through high-temperature hot salt tanks and medium-temperature hot salt tanks can realize the tiered utilization and flexible control of heat of two grades, while also effectively reducing the risk of solidification of high-temperature cold molten salt.

[0016] The high-pressure regenerator group 11, deaerator 9, and low-pressure regenerator group 8 in the coal-fired power generation system are determined according to their specific number of stages and types based on the existing configuration of the coal-fired power generation system. When the high-pressure cylinder 2 operates at zero output, the heating steam source for the high-pressure regenerator group 11 corresponding to the original high-pressure cylinder 2 extraction steam is switched to steam after heat exchange with the main steam. The advantage is that it ensures that the boiler feedwater inlet temperature remains within the normal operating temperature range even when the high-pressure cylinder 2 operates at zero output.

[0017] The measures to ensure safe operation of the high-pressure cylinder under zero-output conditions include: First, adjusting the main reheat steam connecting valve 17 to control the pressure and flow rate of cooling steam entering the high-pressure cylinder 2; second, dynamically adjusting the opening of the high-pressure cylinder exhaust valve 15 to match the vacuum level of the condenser 6; and third, installing a pre-spray water cooling device in the delivery pipe section before the cooling steam enters the high-pressure cylinder 2, and adjusting the water spray cooling according to the monitored steam temperature values ​​at the inlet and outlet of the high-pressure cylinder 2. The advantage is that zero output of the high-pressure cylinder can be achieved with only simple modifications.

[0018] The operating parameters of the coal-fired power generation system must meet the following constraints: Boiler 1 operates within the safe and stable operating boundary and meets environmental emission standards; the exhaust steam temperatures of high-pressure cylinder 2 and low-pressure cylinder 4 are both controlled within the design allowable range; the axial thrust of high-pressure cylinder 2 and intermediate-pressure cylinder 3 is controlled within the design allowable range of the thrust bearings; during deep peak shaving, deaerator 9 does not experience self-boiling. The advantage is that it ensures the safe operation of the coal-fired power generation system under wide load conditions.

[0019] The operating parameters of the molten salt thermal storage system must meet the following constraints: the main steam molten salt heat exchanger 21 is a counter-flow shell-and-tube heat exchanger, and the heat exchange temperature difference must be above 10℃; the molten salt temperature in the high-temperature cold salt tank 18 must be at least 20℃ higher than the molten salt temperature in the medium-temperature hot salt tank 29; the reheat steam molten salt heat exchanger 28 is a counter-flow shell-and-tube heat exchanger, and the heat exchange pinch point temperature must be above 5℃; the molten salt temperature in the medium-temperature hot salt tank 29 is at least 5℃ higher than the outlet feedwater temperature of the high-pressure regenerator group 11 under the rated load of the coal-fired power generation system; the molten salt temperature in the medium-temperature cold salt tank 25 is at least 5℃ higher than the outlet feedwater temperature of the feedwater pump 10 under the rated load of the coal-fired power generation system. The advantage is that while avoiding an excessively large heat exchange area, it also ensures a sufficient heat exchange temperature difference, guaranteeing the normal operation of the heat exchange process of the molten salt thermal storage system under wide load conditions.

[0020] Measures to ensure the normal operation of the molten salt thermal storage system include: during deep peak shaving, coordinating the operation of condensate pump 7 and feedwater pump 10, and the opening of main steam diversion valve 23 and reheat steam diversion valve 30 to ensure that the molten salt temperature in the high-temperature cold salt tank 18, high-temperature hot salt tank 22, medium-temperature cold salt tank 25, and medium-temperature hot salt tank 29 is within the required range; during the heat release phase of the molten salt thermal storage system, coordinating the operation of high-temperature hot salt pump 36 and medium-temperature hot salt pump 32, and the opening of feedwater diversion valve 35, molten salt steam generator diversion valve 39, high-temperature hot salt valve 37, and medium-temperature hot salt valve 33 to ensure that the heat exchange pinch point temperature in the molten salt steam generator 38 is higher than 5℃. The advantage lies in fully utilizing existing regulation methods in the coal-fired power generation system and the molten salt thermal storage system to ensure the normal operation of the molten salt thermal storage system and to guarantee its operational flexibility.

[0021] An operation method for a coal-fired power generation system based on zero output of a high-pressure cylinder and extraction steam thermal storage is as follows: 1) When the coal-fired power generation system requires deep peak shaving, close the main steam valve 12, the first steam shut-off valve 14, and the second steam shut-off valve group 16; open the high-pressure cylinder exhaust valve 15 and the main reheat steam connecting valve 17. A small amount of reheat steam enters the high-pressure cylinder 2 as cooling steam and flows to the condenser 6, with the high-pressure cylinder in a zero-output state; open the main steam diversion valve 23, the reheat steam diversion valve 30, and the high-pressure regenerator group steam control valve group 24. After all the main steam releases superheated heat in the main steam molten salt heat exchanger 21, it is divided into two paths: one path flows to the cold section reheat steam inlet of boiler 1, and the other path flows to the high-pressure regenerator after being regulated by the high-pressure regenerator group steam control valve group 24. At the steam inlet of unit 11, a large amount of hot-section reheat steam releases heat from the superheated and latent heat sections in the reheat steam molten salt heat exchanger 28, and then flows sequentially through the feedwater preheater 31 and the low-pressure regenerator group 8, reducing the output power of generator 5. On the molten salt side, the molten salt in the high-temperature cold salt tank 18 flows sequentially through the high-temperature cold salt pump 19 and the high-temperature cold salt valve 20, and after absorbing heat from the superheated section of the main steam in the main steam molten salt heat exchanger 21, it flows to the high-temperature hot salt tank 22. The molten salt in the medium-temperature cold salt tank 25 flows sequentially through the medium-temperature cold salt pump 26 and the medium-temperature cold salt valve 27, and after absorbing heat from the superheated and latent heat sections of the hot-section reheat steam in the reheat steam molten salt heat exchanger 28, it flows to the medium-temperature hot salt tank 29. 2) When the coal-fired power generation system needs to rapidly increase the load, the feedwater diversion valve 35 and the molten salt steam generator diversion valve 39 are opened. The feedwater enters the molten salt feedwater heat exchanger 34 and absorbs heat before being divided into two paths: one path flows to the feedwater inlet of boiler 1; the other path enters the molten salt steam generator 38 after passing through the molten salt steam generator diversion valve 39 and absorbs heat to become superheated steam. After being regulated by the supplementary steam regulating valve 40, it merges with the hot section reheat steam and enters the turbine to do work, increasing the output power of generator 5. On the molten salt side, the medium-temperature hot salt in the medium-temperature hot salt tank 29 flows sequentially through the medium-temperature hot salt pump 32 and the medium-temperature hot salt valve 33 to preheat the feedwater in the molten salt feedwater heat exchanger 34. The high-temperature hot salt in the high-temperature hot salt tank 22 flows sequentially through the high-temperature hot salt pump 36 and the high-temperature hot salt valve 37 to heat the diverted feedwater in the molten salt steam generator 38 to generate superheated steam. 3) When the coal-fired power generation system does not require deep peak shaving and rapid load increase, the heat storage circuit and heat release circuit of the molten salt thermal storage system are in thermal standby mode, and the coal-fired power generation system is in normal operating condition.

[0022] This invention incorporates high-pressure cylinder zero-output technology and a molten salt thermal storage system into a coal-fired power generation system. While ensuring the safe and stable operation of the boiler, it not only significantly reduces the external power output of the coal-fired power generation system but also enables rapid adjustment of the external power output. The synergistic use of high-temperature and medium-temperature molten salt in the molten salt thermal storage system achieves full storage and utilization of steam thermal energy, significantly enhancing the operational flexibility of the coal-fired power generation system.

[0023] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solutions disclosed in the present invention, various modifications or variations that can be made by those skilled in the art without creative effort should be included within the scope of protection of the present invention.

Claims

1. A coal-fired power generation system based on zero output of a high-pressure cylinder and extraction steam thermal storage, characterized in that: This includes coal-fired power generation systems and molten salt thermal storage systems; The coal-fired power generation system includes a boiler (1), a high-pressure cylinder (2), a medium-pressure cylinder (3), a low-pressure cylinder (4), a generator (5), a condenser (6), a condensate pump (7), a low-pressure regenerator group (8), a deaerator (9), a feedwater pump (10), a high-pressure regenerator group (11), a main steam valve (12), and a central regulating valve (13). The main steam outlet of the boiler (1) is connected to the steam inlet of the high-pressure cylinder (2) through the main steam valve (12). The exhaust outlet of the high-pressure cylinder (2) is connected to the cold section reheat steam inlet of the boiler (1). The hot section reheat steam outlet of the boiler (1) is connected to the steam inlet of the medium-pressure cylinder (3) through the central regulating valve (13). The exhaust outlet of the medium-pressure cylinder (3) is connected to the steam inlet of the low-pressure cylinder (4). The exhaust outlet of the low-pressure cylinder (4) is connected to the steam inlet of the condenser (6). The condensate outlet of the condenser (6) is connected to the steam inlet of the condenser (6). The condensate pump (7) inlet is connected to the condensate outlet of the condensate pump (7) and the condensate inlet of the low-pressure regenerator group (8). The condensate outlet of the low-pressure regenerator group (8) and the condensate inlet of the deaerator (9) are connected to the saturated water outlet of the deaerator (9) and the inlet of the feed water pump (10). The outlet of the feed water pump (10) and the feed water inlet of the high-pressure regenerator group (11) are connected to the feed water inlet of the high-pressure regenerator group (11). The feed water outlet of the high-pressure cylinder (2) is connected to the steam inlet of the high-pressure regenerator group (11). The steam outlet of the intermediate-pressure cylinder (3) is connected to the steam inlet of the deaerator (9). The steam outlet of the low-pressure cylinder (4) is connected to the steam inlet of the low-pressure regenerator group (8). The high-pressure cylinder (2), intermediate-pressure cylinder (3) and low-pressure cylinder (4) drive the generator (5) through the rotating shaft to output electrical power to the outside. The technical modification of the zero-output high-pressure cylinder (2) in the coal-fired power generation system includes: adding a first steam shut-off valve (14) to the connecting pipe between the exhaust port of the high-pressure cylinder (2) and the reheat steam inlet of the cold section of the boiler (1); adding a steam pipe to the exhaust port of the high-pressure cylinder (2) and connecting it to the steam inlet of the condenser (6) through the exhaust valve (15) of the high-pressure cylinder; adding a second steam shut-off valve group (16) to the connecting pipe between the extraction outlet of the high-pressure cylinder (2) and the steam inlet of the high-pressure regenerator group (11); adding a steam pipe to the reheat steam outlet of the hot section of the boiler (1) and connecting it to the steam inlet of the high-pressure cylinder (2) through the main reheat steam connecting valve (17); The molten salt side of the molten salt thermal storage system includes a high-temperature cold salt tank (18), a high-temperature cold salt pump (19), a high-temperature cold salt valve (20), a main steam molten salt heat exchanger (21), a high-temperature hot salt tank (22), a medium-temperature cold salt tank (25), a medium-temperature cold salt pump (26), a medium-temperature cold salt valve (27), a reheat steam molten salt heat exchanger (28), a medium-temperature hot salt tank (29), a medium-temperature hot salt pump (32), a medium-temperature hot salt valve (33), and a molten salt feedwater heat exchanger (34). The system includes a hot salt pump (36), a high-temperature hot salt valve (37), and a molten salt steam generator (38). In the heat storage circuit, the molten salt outlet of the high-temperature cold salt tank (18) is connected to the molten salt inlet of the high-temperature cold salt valve (20) via the high-temperature cold salt pump (19). The molten salt outlet of the high-temperature cold salt valve (20) is connected to the molten salt inlet of the main steam molten salt heat exchanger (21). The molten salt outlet of the main steam molten salt heat exchanger (21) is connected to the molten salt inlet of the high-temperature hot salt tank (22). The molten salt outlet of the medium-temperature cold salt tank (25) is connected to the molten salt outlet of the hot salt tank (25). The intermediate-temperature cold salt pump (26) is connected to the molten salt inlet of the intermediate-temperature cold salt valve (27). The molten salt outlet of the intermediate-temperature cold salt valve (27) is connected to the molten salt inlet of the reheat steam molten salt heat exchanger (28). The molten salt outlet of the reheat steam molten salt heat exchanger (28) is connected to the molten salt inlet of the intermediate-temperature hot salt tank (29). In the heat release circuit, the molten salt outlet of the high-temperature hot salt tank (22) is connected to the molten salt inlet of the high-temperature hot salt valve (37) via the high-temperature hot salt pump (36). The molten salt outlet of the high-temperature hot salt valve (37) is connected to the molten salt outlet of the high-temperature hot salt tank (29). The molten salt inlet of the molten salt steam generator (38) is connected to the molten salt outlet of the molten salt steam generator (38) and the molten salt inlet of the high-temperature cold salt tank (18). The molten salt outlet of the medium-temperature hot salt tank (29) is connected to the molten salt inlet of the medium-temperature hot salt valve (33) via the medium-temperature hot salt pump (32). The molten salt outlet of the medium-temperature hot salt valve (33) is connected to the molten salt inlet of the molten salt feed water heat exchanger (34). The molten salt outlet of the molten salt feed water heat exchanger (34) is connected to the molten salt inlet of the medium-temperature cold salt tank (25). The connection relationship between the steam-water side of the molten salt thermal storage system and the coal-fired power generation system is as follows: The main steam outlet of boiler (1) is connected to the steam inlet of the main steam molten salt heat exchanger (21) via the main steam diversion valve (23). The steam outlet of the main steam molten salt heat exchanger (21) is divided into two paths: one path is connected to the reheat steam inlet of the cold section of boiler (1), and the other path is connected to the steam inlet of the high-pressure regenerator group (11) via the steam control valve group (24) of the high-pressure regenerator group. The reheat steam outlet of the hot section of boiler (1) is connected to the steam inlet of the reheat steam molten salt heat exchanger (28) via the reheat steam diversion valve (30). The water outlet of the reheat steam molten salt heat exchanger (28) is connected to the hot side water inlet of the feedwater preheater (31). The hot side water outlet of the feedwater preheater (31) is connected to the drain inlet of the low-pressure regenerator group (8). The cold-side water inlet of the preheater (31) is connected to the water outlet of the feed pump (10), and the cold-side water outlet of the preheater (31) is connected to the water inlet of the high-pressure regenerator group (11). The cold-side water outlet of the preheater (31) is also connected to the water inlet of the molten salt feed heat exchanger (34) through the feed diversion valve (35). The water outlet of the molten salt feed heat exchanger (34) is divided into two paths. One path is connected to the water inlet of the boiler (1), and the other path is connected to the water inlet of the molten salt steam generator (38) through the molten salt steam generator diversion valve (39). The steam outlet of the molten salt steam generator (38) is connected to the steam inlet of the supplementary steam regulating valve (40), and the steam outlet of the supplementary steam regulating valve (40) is connected to the reheat steam outlet of the hot section of the boiler (1).

2. The coal-fired power generation system based on zero output of a high-pressure cylinder and extraction steam thermal storage according to claim 1, characterized in that: The high-pressure regenerator group (11), deaerator (9) and low-pressure regenerator group (8) in the coal-fired power generation system are determined according to their specific number of stages and type based on the existing configuration of the coal-fired power generation system; when the high-pressure cylinder (2) is in zero-output condition, the heating steam source of the high-pressure regenerator group (11) corresponding to the original high-pressure cylinder (2) is switched to the steam after the main steam heat exchange.

3. A coal-fired power generation system based on zero output of a high-pressure cylinder and extraction steam thermal storage as described in claim 1, characterized in that: The measures to ensure safe operation of the high-pressure cylinder under zero-output conditions are as follows: First, adjust the main reheat steam connecting valve (17) to control the pressure and flow rate of cooling steam entering the high-pressure cylinder (2); Second, dynamically adjust the opening of the high-pressure cylinder exhaust valve (15) and match it with the vacuum degree of the condenser (6); Third, install a pre-spray water de-cooling device in the conveying pipe section before the cooling steam enters the high-pressure cylinder (2), and adjust the spray water de-cooling according to the monitoring value of the steam temperature at the inlet and outlet of the high-pressure cylinder (2).

4. A coal-fired power generation system based on zero output of a high-pressure cylinder and extraction steam thermal storage as described in claim 1, characterized in that: The operating parameters of the coal-fired power generation system must meet the following constraints: the boiler (1) is operating within the safe and stable operating boundary and meets the environmental emission indicators; the exhaust temperature of the high-pressure cylinder (2) and the low-pressure cylinder (4) is controlled within the design allowable range; the axial thrust of the high-pressure cylinder (2) and the medium-pressure cylinder (3) is controlled within the thrust design allowable range of the matching thrust bearing; during deep peak shaving, the deaerator (9) does not have its own boiling.

5. A coal-fired power generation system based on zero output of a high-pressure cylinder and extraction steam thermal storage according to claim 1, characterized in that: The operating parameters of the molten salt thermal storage system must meet the following constraints: the main steam molten salt heat exchanger (21) is a counter-current shell-and-tube heat exchanger, and the heat exchange temperature difference must be above 10℃; the molten salt temperature in the high-temperature cold salt tank (18) must be above 20℃ higher than the molten salt temperature in the medium-temperature hot salt tank (29); the reheat steam molten salt heat exchanger (28) is a counter-current shell-and-tube heat exchanger, and the heat exchange pinch point temperature must be above 5℃; the molten salt temperature in the medium-temperature hot salt tank (29) is above 5℃ higher than the outlet feedwater temperature of the high-pressure regenerator group (11) under the rated load of the coal-fired power generation system; and the molten salt temperature in the medium-temperature cold salt tank (25) is above 5℃ higher than the outlet feedwater temperature of the feedwater pump (10) under the rated load of the coal-fired power generation system.

6. A coal-fired power generation system based on zero output of a high-pressure cylinder and extraction steam thermal storage according to claim 1, characterized in that: Measures to ensure the normal operation of the molten salt thermal storage system include: during deep peak shaving, coordinating the operation status of the condensate pump (7) and feedwater pump (10), the opening of the main steam diversion valve (23) and reheat steam diversion valve (30) to ensure that the molten salt temperature in the high-temperature cold salt tank (18), high-temperature hot salt tank (22), medium-temperature cold salt tank (25) and medium-temperature hot salt tank (29) is within the required range; during the heat release phase of the molten salt thermal storage system, coordinating the operation status of the high-temperature hot salt pump (36) and medium-temperature hot salt pump (32), the opening of the feedwater diversion valve (35), the molten salt steam generator diversion valve (39), the high-temperature hot salt valve (37) and the medium-temperature hot salt valve (33) to ensure that the heat exchange pinch point temperature in the molten salt steam generator (38) is higher than 5°C.

7. The operation method of a coal-fired power generation system based on zero output of a high-pressure cylinder and extraction steam thermal storage according to any one of claims 1-6, characterized in that: Specifically as follows: 1) When the coal-fired power generation system needs deep peak shaving, close the main steam valve (12), the first steam shut-off valve (14) and the second steam shut-off valve group (16), open the high-pressure cylinder exhaust valve (15) and the main reheat steam connecting valve (17), and a small amount of reheat steam enters the high-pressure cylinder (2) as cooling steam and flows to the condenser (6), and the high-pressure cylinder is in a zero-output state; open the main steam diversion valve (23), the reheat steam diversion valve (30) and the high-pressure regenerator group steam control valve group (24), and all the main steam releases the superheated section heat in the main steam molten salt heat exchanger (21) and is divided into two paths, one of which flows to the cold section reheat steam inlet of the boiler (1), and the other flows to the high-pressure regenerator group after being regulated by the high-pressure regenerator group steam control valve group (24). (11) At the steam inlet, a large amount of hot-section reheat steam releases heat from the superheated and latent heat sections in the reheat steam molten salt heat exchanger (28), and flows sequentially through the feedwater preheater (31) and the low-pressure regenerator group (8), reducing the output power of the generator (5); on the molten salt side, the molten salt in the high-temperature cold salt tank (18) flows sequentially through the high-temperature cold salt pump (19) and the high-temperature cold salt valve (20), and after absorbing heat from the superheated section of the main steam in the main steam molten salt heat exchanger (21), it flows to the high-temperature hot salt tank (22); the molten salt in the medium-temperature cold salt tank (25) flows sequentially through the medium-temperature cold salt pump (26) and the medium-temperature cold salt valve (27), and after absorbing heat from the superheated and latent heat sections of the hot-section reheat steam in the reheat steam molten salt heat exchanger (28), it flows to the medium-temperature hot salt tank (29); 2) When the coal-fired power generation system needs to rapidly increase the load, the feedwater diversion valve (35) and the molten salt steam generator diversion valve (39) are opened. The feedwater enters the molten salt feedwater heat exchanger (34) and absorbs heat before being divided into two paths: one path flows to the feedwater inlet of the boiler (1); the other path enters the molten salt steam generator (38) through the molten salt steam generator diversion valve (39) and absorbs heat to become superheated steam. After being regulated by the supplementary steam regulating valve (40), it merges with the reheat steam in the hot section. When the steam enters the turbine to do work, the output power of the generator (5) increases; on the molten salt side, the medium-temperature hot salt in the medium-temperature hot salt tank (29) flows through the medium-temperature hot salt pump (32) and the medium-temperature hot salt valve (33) in sequence, and preheats the feedwater in the molten salt feedwater heat exchanger (34); the high-temperature hot salt in the high-temperature hot salt tank (22) flows through the high-temperature hot salt pump (36) and the high-temperature hot salt valve (37) in sequence, and heats the diverted feedwater in the molten salt steam generator (38) to generate superheated steam; 3) When the coal-fired power generation system does not require deep peak shaving and rapid load increase, the heat storage circuit and heat release circuit of the molten salt thermal storage system are in thermal standby mode, and the coal-fired power generation system is in normal operating condition.

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