Thermal power coupling multi-heat-source modular composite heat storage system and control method thereof

Abstract

The invention belongs to the technical field of thermal power generation and energy storage, and relates to a thermal power coupling multi-heat-source modular composite heat storage system and a control method thereof, and the thermal power coupling multi-heat-source modular composite heat storage system comprises a thermal power generation system and a multi-heat-source modular composite heat storage system; the thermal power generation system comprises a boiler, a steam turbine, a generator, a condenser, a low-temperature heater, a deaerator, a high-temperature heater, a first steam-water separator and an auxiliary steam header; the multi-heat-source modular composite heat storage system comprises an electric heater, a modular heat storage device, a second steam-water separator, an energy storage heat exchanger, a low-temperature storage tank, a high-temperature storage tank and an energy release heat exchanger. Cascade utilization of steam energy is achieved through coupling of the modular fused salt heat storage device and the heat conduction oil / pressurized water heat storage device, high-temperature sensible heat and medium-temperature latent heat of steam are completely stored, the steam extraction amount is greatly reduced, rapid and deep peak regulation of the thermal power generating unit is achieved in cooperation with an electric heat source of the modular fused salt heat storage device, and the thermal power generating unit is protected. Meanwhile, the boiler starting function is achieved, and thermal power flexibility and economical efficiency are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of thermal power generation and energy storage technology, and relates to a multi-heat source modular composite thermal storage system coupled with thermal power and its control method. Background Technology

[0002] Due to the significant growth and volatility of new energy sources, thermal power generation is gradually shifting from a basic energy source to a regulating energy source. However, thermal power units, especially older ones, have poor peak-shaving capabilities, with minimum operating output typically exceeding 30% Pe and load fluctuation rates usually between 2% and 2.5% Pe / min. Furthermore, coal consumption for power generation increases dramatically at low loads, making it difficult to meet the grid's growing peak-shaving demands. In addition, thermal power units cannot generate steam before boiler ignition, while some equipment requires pre-heating steam to support normal ignition. Currently, small oil-fired or coal-fired boilers are mainly used for start-up, which suffers from slow start-up speed, high risk, and high fuel costs.

[0003] Molten salt thermal energy storage technology is a feasible solution to the above problems. For example, patent application CN202510236657.6 describes a steam and electricity thermal energy coupling system and method that stores excess electrical and thermal energy from thermal power units using molten salt, reducing the grid output of thermal power during off-peak hours. Simultaneously, during peak electricity demand, the thermal energy is rapidly released back to the generating units, achieving rapid peak power generation. Furthermore, the thermal energy stored in the energy storage system can be used to supply the steam required for starting up thermal power units, replacing the original starting boiler and achieving two benefits at once.

[0004] However, conventional dual-tank molten salt systems have significant drawbacks: 1. During operation, the pipeline electric heat tracing system must be maintained continuously to prevent the molten salt from solidifying during transportation, resulting in additional energy consumption; 2. During tank shutdowns, continuous electric heating is required to maintain the molten salt in a liquid state, leading to high operation and maintenance costs; 3. Dual-tank thermal storage systems are large in size, resulting in high investment costs; 4. System reliability is limited by the construction quality of large storage tanks, and a single point of failure can cause the entire system to shut down. Furthermore, while electrically heated molten salt can achieve zero generator output, the energy storage conversion efficiency is only 30%~40%; steam-heated molten salt can achieve a conversion efficiency exceeding 70%, but the currently mature binary and ternary molten salts have high melting points, making it difficult to fully utilize the latent heat during steam heating. If only sensible heat is utilized, it will lead to excessive steam extraction, resulting in insufficient safety and economy, and thermal power units will struggle to supply large amounts of extraction steam during low-load operation. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a multi-heat source modular composite thermal storage system coupled with thermal power and its control method, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A multi-heat-source modular composite thermal energy storage system coupled with thermal power includes a thermal power generation system and a multi-heat-source modular composite thermal energy storage system; The thermal power generation system includes a boiler, a steam turbine, a generator, a condenser, a cryogenic heater, a deaerator, a high-temperature heater, a first steam-water separator, and an auxiliary steam header; the multi-heat source modular composite thermal energy storage system includes an electric heater, a modular thermal energy storage device, a second steam-water separator, an energy storage heat exchanger, a cryogenic storage tank, a high-temperature storage tank, and an energy release heat exchanger, wherein the modular thermal energy storage device includes a modular thermal energy storage medium and heat exchange pipes arranged in the modular thermal energy storage medium; The steam outlet of the boiler is connected to the steam turbine and drives the generator to generate electricity. The outlet of the steam turbine is connected in sequence to the condenser, the water side of the low-temperature heater, the deaerator, the water side of the high-temperature heater, and the feedwater inlet of the boiler. The steam-side inlets of the high-temperature heater and the low-temperature heater, as well as the deaerator, are all connected to the turbine outlet. The steam-side condensate outlet of the high-temperature heater is connected to the deaerator, and the steam-side condensate outlet of the low-temperature heater is connected to the condenser. The steam outlet of the first steam-water separator is connected to the auxiliary steam header, and the condensate outlet is connected to the deaerator. The electric heater is connected to the generator. The bottom molten salt outlet of the module heat storage device is connected to the electric heater, and the molten salt outlet of the electric heater is connected to the top of the module heat storage device. The heat exchange pipe of the module heat storage device is connected to the water side of the high temperature heater and the inlet of the first steam-water separator, and is connected to the inlet of the second steam-water separator and the steam outlet of the boiler. The outlet of the second steam-water separator is connected in sequence to the hot side of the energy storage heat exchanger and the water side of the low temperature heater. The cold side of the energy release heat exchanger is connected to the water side of the low-temperature heater, and the outlet of the low-temperature storage tank is sequentially connected to the cold side of the energy storage heat exchanger, the high-temperature storage tank, the hot side of the energy release heat exchanger, and the inlet of the low-temperature storage tank.

[0008] Furthermore, the modular thermal storage device includes multiple parallel modular thermal storage units, with at least two parallel units; each modular thermal storage unit connects molten salts in multiple thermal storage modules in series through an overflow pipe, with at least two modules connected in series, and each modular thermal storage unit connects heat exchange pipes in multiple thermal storage modules in series through an external steam-water pipe; the modular thermal storage device supports both electric heating and steam heating methods, and can operate independently or in combination.

[0009] Furthermore, the modular thermal storage device is provided with at least three thermal storage modules, and the inlet of the bottom thermal storage module of the modular thermal storage device is directly connected to the steam and water pipe connected to the outlet of the top thermal storage module through the twenty-second steam and water valve; The middle heat storage module of the modular heat storage device is directly connected to the steam and water pipe connected to the outlet of the top heat storage module through the twenty-first steam and water valve, and the number of middle modules is at least one.

[0010] Furthermore, the high-temperature heater includes at least a third high-temperature heater, a second high-temperature heater, and a first high-temperature heater connected in series; The heat exchange pipes of the modular thermal storage device are connected to the water-side inlet or outlet of multiple high-temperature heaters in the thermal power generation system. The heat exchange pipes of the top thermal storage module are connected to the water side of the high-temperature heaters through at least two steam-water valves, and the heat exchange pipes of the bottom thermal storage module are connected to the water side of the high-temperature heaters through at least one steam-water valve.

[0011] Furthermore, the cryogenic heater includes at least a third cryogenic heater, a second cryogenic heater, and a first cryogenic heater connected in series; The connection position between the hot side outlet of the energy storage heat exchanger and the water side of the low-temperature heater is determined based on the temperature matching principle, and the absolute value of the temperature difference between the hot side outlet temperature of the energy storage heat exchanger and the temperature at the connection position of the water side of the low-temperature heater is controlled to not exceed 20℃.

[0012] Furthermore, the steam turbine includes a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder connected in series. The boiler has a feedwater inlet, a main steam outlet, a reheat steam inlet, and a reheat steam outlet. The main steam outlet of the boiler is connected to the inlet of the high-pressure cylinder, and the outlet of the high-pressure cylinder is connected to the reheat steam inlet of the boiler. The reheat steam outlet of the boiler is connected in sequence to the intermediate-pressure cylinder and the low-pressure cylinder and drives the generator to generate electricity.

[0013] Furthermore, the outlet of the high-pressure cylinder is connected to the second high-temperature heater and the first high-temperature heater respectively through two steam-water valves, the outlet of the medium-pressure cylinder is connected to the third high-temperature heater, the deaerator and the first low-temperature heater respectively through three steam-water valves, and the outlet of the low-pressure cylinder is connected to the remaining low-temperature heaters respectively through multiple steam-water valves.

[0014] Furthermore, a condensate pump and a shaft seal heater are sequentially provided between the condenser and the low-temperature heater, a feed water pump is provided between the deaerator and the high-temperature heater, and a start-up water pump is provided between the deaerator and the energy release heat exchanger. A molten salt pump is provided between the molten salt outlet at the bottom of the module thermal storage device and the electric heater. A low-temperature pump and a high-temperature pump are respectively provided between the outlet of the low-temperature storage tank and the energy storage heat exchanger, and between the high-temperature storage tank and the energy release heat exchanger.

[0015] Furthermore, a transformer is provided between the electric heater and the generator.

[0016] Furthermore, the multi-heat source modular composite thermal storage system is configured as a start-up boiler for a thermal power generation system, wherein the heat exchange pipe of the modular thermal storage device is connected to the inlet of the first steam-water separator and to the cold-side outlet of the energy release heat exchanger, and the cold-side inlet of the energy release heat exchanger is sequentially connected to the start-up water pump and the deaerator outlet.

[0017] Furthermore, the heat storage medium of the modular heat storage device is molten salt or a combination of molten salt and solid heat storage medium; the heat storage medium in the low-temperature storage tank and the high-temperature storage tank is water, heat transfer oil or a combination of liquid and solid heat storage medium.

[0018] Furthermore, the heat exchange pipes of the modular heat storage device are connected to the reheat steam outlet of the boiler, supporting the cascade utilization of steam energy, realizing the storage of high-temperature sensible heat and medium-temperature latent heat, and reducing the amount of steam extracted.

[0019] On the other hand, the present invention also provides a control method for a multi-heat source modular composite thermal energy storage system coupled with thermal power, applicable to the above-mentioned system, including an energy storage stage and an energy release stage; The energy storage phase includes electric energy storage mode, steam energy storage mode, and electric-steam hybrid energy storage mode; In electric energy storage mode, the molten salt pump is started, and the generator supplies power to the electric heater to heat the molten salt. The frequency of the molten salt pump and the power of the electric heater are adjusted according to the preset molten salt outlet temperature. The molten salt flows from the bottom of the module thermal storage device through the molten salt pump and the electric heater to the top, and then flows down through the overflow pipe to achieve energy storage. In steam energy storage mode, the molten salt pump and the cryogenic pump are started; the flow rate of the steam-water pipeline on the hot side of the energy storage heat exchanger, the frequency of the molten salt pump and the cryogenic pump are adjusted so that the outlet temperature and flow rate of the module heat storage device and the energy storage heat exchanger on the hot side reach the set values; after the steam from the thermal power generation system enters the module heat storage device, the steam and condensate are separated by the second steam-water separator and enter the heat side of the energy storage heat exchanger to heat the medium in the cryogenic storage tank, and the condensate is returned to the water side of the cryogenic heater; In the electric-steam hybrid energy storage mode, the molten salt pump, cryogenic pump, and electric heater are started simultaneously; the power of the electric heater, the flow rate of the steam-water pipeline where the heat side of the energy storage heat exchanger is located, and the frequency of the molten salt pump and cryogenic pump are adjusted so that the outlet temperature and flow rate of the module heat storage device and the heat side of the energy storage heat exchanger reach the set values, and the molten salt outlet temperature of the electric heater is constrained to avoid overheating.

[0020] Furthermore, the energy release phase includes a feedwater mode for heating a high-temperature heater, a feedwater mode for heating a low-temperature heater, and a feedwater mode for heating both high- and low-temperature heaters. In the high-temperature heater feedwater mode, the molten salt pump is started. In the early stage of energy release, the cold side outlet of the module thermal storage device is directly connected to the water side inlet of the boiler or high-temperature heater. The flow rate of the steam-water pipeline and the frequency of the molten salt pump connected to the water side of the high-temperature heater are adjusted so that the cold side flow rate and outlet temperature of the module thermal storage device reach the set values. In the later stage of energy release, the cold side outlet temperature of the module thermal storage device decreases. The water side inlet of the high-temperature heater connected to the cold side outlet of the module thermal storage device is controlled, and the flow rate of the steam-water pipeline and the frequency of the molten salt pump connected to the water side of the high-temperature heater are readjusted so that the cold side flow rate and outlet temperature of the module thermal storage device reach the new set values. In the low-temperature heater feedwater mode, start the high-temperature pump, open the steam-water pipeline where the cold side of the energy release heat exchanger is located and adjust its flow rate, adjust the frequency of the high-temperature pump, so that the flow rate and outlet temperature of the cold side of the energy release heat exchanger reach the set values. In the heating mode of the high and low temperature heater feedwater, the molten salt pump and the high temperature pump are started simultaneously. In the early stage of energy release, the cold side outlet of the module thermal storage device is directly connected to the water side inlet of the boiler or the high temperature heater. The steam-water pipeline where the cold side of the energy release heat exchanger is located is opened and its flow rate is adjusted. The flow rate of the steam-water pipeline, the frequency of the molten salt pump and the frequency of the high temperature pump, which are connected to the water side of the high temperature heater by the cold side inlet of the module thermal storage device are adjusted respectively, so that the cold side flow rate and outlet temperature of the module thermal storage device and the energy release heat exchanger reach the set values. In the later stage of energy release, the cold-side outlet temperature of the modular thermal storage device decreases. The water-side inlet of the high-temperature heater connected to the cold-side outlet of the modular thermal storage device is controlled, and the flow rate of the steam-water pipeline and the frequency of the molten salt pump connected to the water side of the high-temperature heater are readjusted so that the cold-side flow rate and outlet temperature of the modular thermal storage device reach the new set values.

[0021] Furthermore, it also includes a boiler start-up mode, which involves turning on the start-up water pump, molten salt pump, and high-temperature pump, opening the steam-water valves for the feedwater entering the cold side of the energy release heat exchanger, the cold side of the module heat storage device, and the first steam-water separator, and adjusting their opening degree. Adjust the frequency of the start-up water pump to make the steam flow of the auxiliary steam header reach the set value, and adjust the frequency of the molten salt pump and the high-temperature pump to make the cold side outlet temperature of the module heat storage device reach the set value; the feedwater of the deaerator passes through the cold side of the energy release heat exchanger, the heat exchange pipeline of the module heat storage device and the first steam-water separator, and the separated steam is supplied to the auxiliary steam header, while the condensate is returned to the deaerator.

[0022] Furthermore, it also includes backup modes, including short-term hot backup, short-term shutdown hot backup, and long-term shutdown cold backup; Short-term hot standby is suitable for energy storage / release intervals not exceeding 48 hours, requiring no additional measures; Short-term shutdown hot standby is applicable at intervals of 48-480 hours. It requires the supply of 1-20 tons / day of hot steam to maintain operation, and the operation of molten salt pumps and cryogenic pumps. The steam-water valves for the module thermal storage device and energy storage heat exchanger should be opened. If the medium in the cryogenic storage tank is insufficient or the temperature is low, the high-temperature pump should be turned on to supplement it. Long-term shutdown cold standby is suitable for intervals exceeding 480 hours, without any measures, allowing the system to cool down naturally and the molten salt to solidify; when restarting, steam not exceeding 30% of the rated flow rate is introduced, the cryogenic pump and the high-temperature pump are started, and the steam-water valves for the module thermal storage device and the energy storage heat exchanger are opened until the temperature of the thermal storage medium in the module thermal storage device is at least 20°C higher than the melting point of the molten salt, after which it is switched to short-term shutdown hot standby.

[0023] The beneficial effects of this invention are as follows: 1. This invention provides a multi-heat-source modular composite thermal energy storage system coupled with thermal power. It utilizes the coupling of a modular molten salt thermal energy storage device with a heat transfer oil / pressurized water thermal energy storage device (low-temperature and high-temperature tanks) to achieve cascaded utilization of steam energy, fully storing the high-temperature sensible heat and medium-temperature latent heat of the steam, significantly reducing the amount of steam extracted. Simultaneously, it works in conjunction with the electric heat source of the modular molten salt thermal energy storage device to achieve rapid and deep peak shaving for the thermal power unit. During energy release, an innovative multi-path feedwater heating scheme is designed to effectively solve the problem of the gradually decreasing heating temperature that the modular thermal energy storage device can provide at the end of energy release, thereby improving the heat release depth of the modular thermal energy storage device.

[0024] 2. This invention uses a modular molten salt thermal storage device to replace the conventional dual-tank thermal storage scheme. The modular thermal storage unit integrates the storage tank and heat exchanger into one unit, eliminating the need for pipeline electric heat tracing devices. Multiple modular thermal storage units can be easily stacked in series and parallel to form a thermal storage and exchange system. The thermal storage medium in the modular thermal storage unit can solidify when it is not in use. If a single modular thermal storage unit fails, it can be isolated and repaired without shutting down the system. It can achieve standardized factory production and modular installation, with high safety, small footprint, and low investment and operation and maintenance costs, thus solving the defects of dual-tank thermal storage.

[0025] 3. This invention utilizes a multi-heat source modular composite thermal storage system to realize the boiler start-up function of thermal power units. The heat transfer oil / pressurized water thermal storage device first preheats the feedwater from the deaerator, effectively avoiding the solidification of molten salt caused by direct entry into the modular thermal storage device, while realizing energy cascade utilization and solving the defects of the original start-up boiler of thermal power units.

[0026] 4. This invention provides a control method for a multi-heat source modular composite thermal energy storage system coupled with thermal power. The control method includes operating logic under four conditions: energy storage, energy release, boiler start-up, and standby. Among them, energy storage includes three modes: electric energy storage, steam energy storage, and electric-steam hybrid energy storage; energy release includes three modes: heating feedwater for high-temperature heaters, heating feedwater for low-temperature heaters, and heating feedwater for both high- and low-temperature heaters; and standby includes three modes: short-term hot standby, short-term shutdown hot standby, and long-term shutdown cold standby. This invention realizes the functions of rapid and deep peak shaving, boiler start-up, and energy storage standby for thermal power units, effectively improving the flexibility and economy of thermal power.

[0027] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a flowchart of the multi-heat source modular composite thermal storage system coupled with thermal power in Example 1; Figure 2 This is a flowchart of the multi-heat source modular composite thermal storage system coupled with thermal power in Example 2; Figure 3 This is a flowchart of the multi-heat source modular composite thermal energy storage system coupled with thermal power in Example 3; Figure 4 This is a flowchart of multiple parallel modular thermal storage units.

[0029] Figure reference numerals: 1-Boiler; 2-High-pressure cylinder; 3-Medium-pressure cylinder; 4-Low-pressure cylinder; 5-Generator; 6-1-First steam-water valve; 6-2-Second steam-water valve; 6-3-Third steam-water valve; 6-4-Fourth steam-water valve; 6-5-Fifth steam-water valve; 6-6-Sixth steam-water valve; 6-7-Seventh steam-water valve; 6-8-Eighth steam-water valve; 6-9-Ninth steam-water valve; 6-10-Tenth steam-water valve; 6-11-Eleventh steam-water valve; 6-12-Twelfth steam-water valve; 6-13-Thirteenth steam-water valve Water valve; 6-14-Fourteenth steam and water valve; 6-15-Fifteenth steam and water valve; 6-16-Sixteenth steam and water valve; 6-17-Seventeenth steam and water valve; 6-18-Eighteenth steam and water valve; 6-19-Nineteenth steam and water valve; 6-20-Twentieth steam and water valve; 6-21-Twenty-first steam and water valve; 6-22-Twenty-second steam and water valve; 6-23-Twenty-third steam and water valve; 6-24-Twenty-fourth steam and water valve; 6-25-Twenty-fifth steam and water valve; 6-26-Twenty-sixth steam and water valve; 6- 27-Twenty-seventh steam-water valve; 6-28-Twenty-eighth steam-water valve; 6-29-Twenty-ninth steam-water valve; 7-First steam-water separator; 8-Auxiliary steam header; 9-1-First high-temperature heater; 9-2-Second high-temperature heater; 9-3-Third high-temperature heater; 10-1-First low-temperature heater; 10-2-Second low-temperature heater; 10-3-Third low-temperature heater; 11-Deaerator; 12-Feed water pump; 13-Condenser; 14-Condensate pump; 15-Shaft seal heater; 16-Start-up water pump; 17 18-Transformer; 19-Electric heater; 20-Molten salt pump; 21-Module thermal storage device; 20-1-First module thermal storage unit; 20-2-Second module thermal storage unit; 20-3-Third module thermal storage unit; 22-Module thermal storage medium; 23-Overflow pipe; 24-Heat exchange pipe; 25-Second steam-water separator; 26-Energy storage heat exchanger; 27-Cryogenic pump; 28-Cryogenic storage tank; 29-High temperature storage tank; 30-High temperature pump; 31-Energy release heat exchanger; 32-Steam-water pipe; 33-Molten salt pipe; 34-Electrical wiring. Detailed Implementation

[0030] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0031] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0032] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0033] Example 1 Please see Figure 1 This embodiment provides a multi-heat source modular composite thermal energy storage system coupled with thermal power, which includes a thermal power generation system and a multi-heat source modular composite thermal energy storage system. The thermal 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, multiple steam-water valves, a first steam-water separator 7, an auxiliary steam header 8, a high-temperature heater, a low-temperature heater, a deaerator 11, a feedwater pump 12, a condenser 13, a condensate pump 14, a shaft seal heater 15, and a steam-water pipeline 31. The multi-heat source modular composite thermal storage system includes a start-up water pump 16, a transformer 17, an electric heater 18, a molten salt pump 19, a modular thermal storage device 20, a second steam-water separator 24, an energy storage heat exchanger 25, a cryogenic pump 26, a cryogenic storage tank 27, a high-temperature storage tank 28, a high-temperature pump 29, an energy release heat exchanger 30, a steam-water pipeline 31, a molten salt pipeline 32, electrical wiring 33, and a steam-water valve 6. The modular thermal storage device 20 includes a modular thermal storage medium 21, an overflow pipe 22, and a heat exchange pipe 23.

[0034] The main steam outlet of the boiler 1 is connected to the high-pressure cylinder 2, the outlet of the high-pressure cylinder 2 is connected to the reheat steam inlet of the boiler 1, and the reheat steam outlet of the boiler 2 is connected in sequence to the intermediate-pressure cylinder 3 and the low-pressure cylinder 4 and drives the generator 5 to generate electricity. The outlet of the low-pressure cylinder 4 is connected in sequence to the condenser 13, condensate pump 14, shaft seal heater 15, water-side inlet of the low-temperature heater, deaerator 11, feed water pump 12, water-side inlet of the high-temperature heater and feed water inlet of boiler 1 via steam-water pipeline 31. The steam-side inlets of the high-temperature heater and the low-temperature heater are respectively connected to the high-pressure cylinder 2, the intermediate-pressure cylinder 3 and / or the low-pressure cylinder 4, so as to use part of the steam in the turbine to heat the water-side working fluid of the high-temperature heater and the low-temperature heater. The deaerator 11 is connected to the outlet of the intermediate pressure cylinder 3. The condensate outlet of the first high temperature heater 9-1 is connected to the condensate inlet of the second high temperature heater 9-2 through the steam-water pipe 31. The condensate outlet of the second high temperature heater 9-2 is connected to the condensate inlet of the third high temperature heater 9-3 through the steam-water pipe 31. The condensate outlet of the third high temperature heater 9-3 is connected to the deaerator 11 through the steam-water pipe 31. The condensate outlet of the first low-temperature heater 10-1 is connected to the condensate inlet of the second low-temperature heater 10-2 through a steam-water pipe 31. The condensate outlet of the second low-temperature heater 10-2 is connected to the condensate inlet of the third low-temperature heater 10-3 through a steam-water pipe 31. The condensate outlet of the third low-temperature heater 10-3 is connected to the condenser 13 through a steam-water pipe 31. The steam outlet of the first steam-water separator 7 is connected to the auxiliary steam header 8, and the condensate outlet of the first steam-water separator 7 is connected to the deaerator 11. Steam and water valves are installed at each steam and water pipeline 31 in the thermal power generation system to control the opening and closing of each steam and water pipeline 31.

[0035] In the multi-heat source modular composite thermal storage system, the electric heater 18 is connected in sequence to the transformer 17 and the generator 5 in the thermal power generation system via electrical lines 33. The bottom module molten salt outlet of the modular thermal storage device 20 is connected to the molten salt pump 19 and the electric heater 18 in sequence through the molten salt pipe 32, and the molten salt outlet of the electric heater 18 is connected to the top module molten salt inlet of the modular thermal storage device 20. The heat exchange pipe 23 of the modular thermal storage device 20 is connected to the water-side outlet of the first high-temperature heater 9-1, the water-side outlet of the second high-temperature heater 9-2, and the water-side inlet of the third high-temperature heater 9-3 of the thermal power generation system via the steam-water pipe 31. The heat exchange pipe 23 of the modular thermal storage device 20 is connected to the reheat steam outlet of the boiler 1 of the thermal power generation system via the steam-water pipe 31. The heat exchange pipe 23 of the modular heat storage device 20 is connected to the inlet of the second steam-water separator 24 through the steam-water pipe 31, and the outlet of the second steam-water separator 24 is connected in sequence to the hot side inlet of the energy storage heat exchanger 25 and the water side outlet of the first low temperature heater 10-1. The cold side inlet of the energy release heat exchanger 30 is connected to the water side inlet of the third low-temperature heater 10-3, and the cold side outlet of the energy release heat exchanger 30 is connected to the water side outlet of the first low-temperature heater 10-1. The outlet of the cryogenic pump 26 is sequentially connected to the cold side of the energy storage heat exchanger 25, the high-temperature storage tank 28, the high-temperature pump 29, the hot side of the energy release heat exchanger 30, and the inlet of the cryogenic storage tank 27, and the outlet of the cryogenic storage tank 27 is connected to the inlet of the cryogenic pump 26. The steam-water valves are arranged at each steam-water pipe 31 of the multi-heat source modular composite thermal storage system to control the opening and closing of each steam-water pipe 31.

[0036] In this embodiment, the modular thermal storage device 20 is divided into 12 parallel modular thermal storage units, and the connection method of the parallel pipelines is described in [reference needed]. Figure 4 Multiple of the aforementioned module thermal storage units are connected in parallel via steam-water pipes 31; Each modular thermal storage unit has 5 thermal storage modules, and the molten salt in the 5 thermal storage modules is connected in series through the overflow pipe 22, and the heat exchange pipes 23 in the 5 thermal storage modules are connected in series through the external steam and water pipe 31; the modular thermal storage device 20 has two heating methods: electric heat source and steam heat source, and the two methods can be operated independently or in combination.

[0037] The bottom module inlet of the modular thermal storage unit is connected to the steam and water pipe 31, which is connected to the top module outlet via the twenty-second steam and water valve 6-22. The second module outlet of the modular thermal storage unit is connected to the steam and water pipe 31, which is connected to the top module outlet via the external steam and water pipe 31 and the twenty-first steam and water valve 6-21, from bottom to top.

[0038] The heat exchange pipe 23 of the modular thermal storage device 20 is connected to the water-side outlet of the first high-temperature heater 9-1, the water-side outlet of the second high-temperature heater 9-2, and the water-side inlet of the third high-temperature heater 9-3 of the thermal power generation system via the steam-water pipe 31; specifically, the top module of the modular thermal storage device 20 is connected to the water-side outlet of the first high-temperature heater 9-1 and the water-side outlet of the second high-temperature heater 9-2 via the eighteenth steam-water valve 6-18 and the nineteenth steam-water valve 6-19, and the bottom module is connected to the water-side inlet of the third high-temperature heater 9-3 via the thirteenth steam-water valve 6-13.

[0039] The connection position between the hot side outlet of the energy storage heat exchanger 25 and the water side of the low-temperature heater is determined according to the temperature matching principle, and the hot side outlet of the energy storage heat exchanger 25 is connected to the water side outlet of the first low-temperature heater 10-1.

[0040] The multi-heat source modular composite thermal storage system can be used as a start-up boiler for a thermal power generation system. The heat exchange pipe 23 of the modular thermal storage device 20 is connected to the inlet of the first steam-water separator 7 of the thermal power generation system through the steam-water pipe 31. The heat exchange pipe 23 of the modular heat storage device 20 is connected to the cold side outlet of the energy release heat exchanger 30 through the steam-water pipe 31 and the twenty-fifth steam-water valve 6-25 installed on the steam-water pipe 31. The cold side inlet of the energy release heat exchanger 30 is connected in sequence to the start-up water pump 16 and the outlet of the deaerator 11 in the thermal power generation system.

[0041] The heat storage medium 21 of the modular heat storage device 20 adopts a composite heat storage of molten salt and solid heat storage medium; the heat storage medium in the low temperature tank 27 and the high temperature tank 28 is water.

[0042] Specifically, the inlet of the first steam-water separator 7 is equipped with a first steam-water valve 6-1; the steam outlet of the first steam-water separator 7 is connected to the auxiliary steam header via a second steam-water valve 6-2; the condensate outlet of the first steam-water separator 7 is connected to the deaerator via a third steam-water valve 6-3; and a fourth steam-water valve 6-4 is provided on the steam-water pipeline 31 connecting the cold side outlet of the module heat storage device 20 to the inlet of the intermediate-pressure cylinder 3. The outlet of the high-pressure cylinder 2 is connected to the first high-pressure cylinder 2 via a fifth steam-water valve 6-5 and a sixth steam-water valve 6-6, respectively. The steam-side inlets of the high-temperature heater 9-1 and the second high-temperature heater 9-2 are connected to the steam-side inlet of the third high-temperature heater 9-3, the deaerator 11, and the steam-side inlet of the first low-temperature heater 10-1 via the seventh steam-water valve 6-7, the eighth steam-water valve 6-8, and the ninth steam-water valve 6-9, respectively. The outlet of the low-pressure cylinder 4 is also connected to the steam-side inlets of the second low-temperature heater 10-2 and the third low-temperature heater 10-3 via the tenth steam-water valve 6-10 and the eleventh steam-water valve 6-11. The outlet of the water pump 12 is connected to the water-side inlet of the third high-temperature heater 9-3 and the cold-side inlet of the module heat storage device 20 through the 12th steam-water valve 6-12 and the 13th steam-water valve 6-13, respectively. A 23rd steam-water valve 6-23 is also provided between the 13th steam-water valve 6-13 and the cold-side inlet of the module heat storage device 20. The deaerator 11 is connected to the start-up water pump 16 through the 14th steam-water valve 6-14. The shaft seal heater 15 is connected to the water-side inlet of the third low-temperature heater 10-3 and the cold-side inlet of the energy release heat exchanger 30 through the 15th steam-water valve 6-15 and the 16th steam-water valve 6-16, respectively. The start-up water pump 16 is connected to the cold-side inlet of the energy release heat exchanger 30 through the 28th steam-water valve 6-28. The cold side outlet of the modular thermal storage device 20 is provided with a twentieth steam-water valve 6-20, and the outlet of the twentieth steam-water valve 6-20 is connected to the first steam-water valve 6-1 and the fourth steam-water valve 6-4, the water inlet of the boiler 1, and the water side inlet of the first high-temperature heater 9-1 through the seventeenth steam-water valve 6-17, the eighteenth steam-water valve 6-18, and the nineteenth steam-water valve 6-19, respectively. The module heat storage device 20 is provided with a twenty-fourth steam-water valve 6-24 at the cold side inlet, which is connected to the steam-water inlet of the second steam-water separator 24. The cold side outlet of the energy release heat exchanger 30 is connected to the cold side inlet of the module heat storage device 20 and the inlet of the deaerator 11 through the twenty-fifth steam-water valve 6-25 and the twenty-fifth steam-water valve 6-26, respectively. The energy storage heat exchanger 25 is provided with a twenty-seventh steam-water valve 6-27 at the hot side outlet.

[0043] For the energy storage stage, the control logic of the multi-heat source modular composite thermal energy storage system coupled with thermal power is divided into three modes: electric energy storage, steam energy storage, and electric-steam hybrid energy storage. Electric energy storage mode: Molten salt pump 19 starts, generator 5 provides electrical energy which is transmitted to electric heater 18 via transformer 17 to generate heat. The frequency of molten salt pump 19 and the power of electric heater 18 are adjusted according to the preset molten salt outlet temperature until the set load requirement is reached; the first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the fourth steam-water valve 6-4, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, and the seventeenth steam-water valve are closed. Valves 6-17, 18th steam-water valve 6-18, 19th steam-water valve 6-19, 20th steam-water valve 6-20, 21st steam-water valve 6-21, 22nd steam-water valve 6-22, 23rd steam-water valve 6-23, 24th steam-water valve 6-24, 25th steam-water valve 6-25, 26th steam-water valve 6-26, 27th steam-water valve 6-27, and 28th steam-water valve 6-28, and the steam-water valves of the remaining thermal power generation systems remain open; Molten salt flows from the bottom module of the modular thermal storage device 20 through the molten salt pump 19 and the electric heater 18 to the top module. The molten salt in the top module flows down to the bottom module through the overflow pipe 22, so that the entire modular thermal storage device 20 can store energy.

[0044] Steam energy storage mode: Molten salt pump 19 and cryogenic pump 26 are started, the fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 are opened, and the first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, and the nineteenth steam-water valve are opened. Water valve 6-19, steam-water valve 6-21 (21st), steam-water valve 6-22 (22nd), steam-water valve 6-23 (23rd), steam-water valve 6-25 (25th), steam-water valve 6-26 (26th), and steam-water valve 6-28 (28th) are closed, while the steam-water valves of the remaining thermal power generation system remain open; the opening of steam-water valve 6-27 (27th), the frequency of molten salt pump 19, and the cryogenic pump 26 are adjusted to bring the hot-side outlet temperature and flow rate of the module thermal storage device 20 and the energy storage heat exchanger 25 to the set values; Steam from the thermal power generation system first enters the module thermal storage device 20 through the steam-water pipeline 31 containing the fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, and the twentieth steam-water valve 6-20. Then, it enters the second steam-water separator 24 through the twenty-fourth steam-water valve 6-24. The second steam-water separator 24 separates the steam and condensate and feeds them into the hot-side steam inlet and hot-side condensate inlet of the energy storage heat exchanger 25, respectively, to heat the thermal storage medium from the cryogenic storage tank 27. Finally, the condensate returns to the water side of the cryogenic heater 10 of the thermal power generation system through the hot-side outlet of the energy storage heat exchanger 25.

[0045] Electric-steam hybrid energy storage mode: Molten salt pump 19 and cryogenic pump 26 are started. Generator 5 provides electrical energy, which is transmitted to electric heater 18 via transformer 17 to generate heat. The fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 are opened. The first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, and the nineteenth steam-water valve are opened. Water valve 6-19, steam-water valve 6-21 (21st), steam-water valve 6-22 (22nd), steam-water valve 6-23 (23rd), steam-water valve 6-25 (25th), steam-water valve 6-26 (26th), and steam-water valve 6-28 (28th) are closed, while the steam-water valves of the remaining thermal power generation system remain open. The power of electric heater 18, the opening degree of steam-water valve 6-27 (27th), and the frequency of molten salt pump 19 and cryogenic pump 26 are adjusted to bring the hot-side outlet temperature and flow rate of module thermal storage device 20 and energy storage heat exchanger 25 to the set values, while simultaneously constraining the molten salt outlet temperature of electric heater 18 to prevent overheating.

[0046] For the energy release phase, the control logic of the multi-heat source modular composite thermal storage system coupled with thermal power is divided into three modes: heating high-pressure feedwater, heating low-pressure feedwater, and heating both high-pressure and low-pressure feedwater. High-temperature heater feedwater mode: Molten salt pump 19 starts, and during the initial energy release phase, the 12th steam-water valve 6-12, the 13th steam-water valve 6-13, the 23rd steam-water valve 6-23, the 20th steam-water valve 6-20, the 21st steam-water valve 6-21, the 22nd steam-water valve 6-22, and the 18th steam-water valve 6-18 are opened. The 1st steam-water valve 6-1, the 2nd steam-water valve 6-2, the 3rd steam-water valve 6-3, the 4th steam-water valve 6-4, the 14th steam-water valve 6-14, the 16th steam-water valve 6-16, the 17th steam-water valve 6-17, the 19th steam-water valve 6-19, the 24th steam-water valve 6-24, the 25th steam-water valve 6-25, the 26th steam-water valve 6-26, the 27th steam-water valve 6-27, and the 28th steam-water valve 6-28 are closed. The steam-water valves of the remaining thermal power generation system remain open. Adjust the opening of the twelfth steam-water valve 6-12 and the thirteenth steam-water valve 6-13 to make the cold side flow rate entering the module heat storage device 20 reach the set value; Adjust the frequency of molten salt pump 19, the opening of the 20th steam-water valve 6-20, the 21st steam-water valve 6-21, and the 22nd steam-water valve 6-22 to make the cold side outlet temperature of the module thermal storage device 20 reach the set value. During the later stages of energy release, as the cold-side outlet temperature of the module thermal storage device 20 decreases, the eighteenth steam-water valve 6-18 is closed, the nineteenth steam-water valve 6-19 is opened, and the frequency of the molten salt pump 19, the opening of the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, and the twenty-second steam-water valve 6-22 are readjusted to bring the cold-side outlet temperature of the module thermal storage device 20 to a new set value.

[0047] Heating low-temperature heater feedwater mode: High-temperature pump 29 starts, the fifteenth steam-water valve 6-15, the sixteenth steam-water valve 6-16, and the twenty-sixth steam-water valve 6-26 are opened, the first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the fourth steam-water valve 6-4, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the seventeenth steam-water valve 6-17, the eighteenth steam-water valve 6-18, the nineteenth steam-water valve 6-19, the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the twenty-third steam-water valve 6-23, the twenty-fourth steam-water valve 6-24, the twenty-fifth steam-water valve 6-25, the twenty-seventh steam-water valve 6-27, and the twenty-eighth steam-water valve 6-28 are closed, and the steam-water valves of the remaining thermal power generation system remain open; Adjust the opening of the fifteenth steam-water valve 6-15 and the sixteenth steam-water valve 6-16 to make the cold side flow rate entering the energy release heat exchanger 30 reach the set value; adjust the frequency of the high temperature pump 29 to make the cold side outlet temperature of the energy release heat exchanger 30 reach the set value.

[0048] Heating high and low temperature heater feedwater mode: Molten salt pump 19 and high temperature pump 29 are started, the thirteenth steam-water valve 6-13, the twenty-third steam-water valve 6-23, the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the eighteenth steam-water valve 6-18, the sixteenth steam-water valve 6-16, and the twenty-sixth steam-water valve 6-26 mentioned in the energy release phase are opened, the first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the fourth steam-water valve 6-4, the fourteenth steam-water valve 6-14, the seventeenth steam-water valve 6-17, the nineteenth steam-water valve 6-19, the twenty-fourth steam-water valve 6-24, the twenty-fifth steam-water valve 6-25, the twenty-seventh steam-water valve 6-27, and the twenty-eighth steam-water valve 6-28 are closed, and the steam-water valves of the remaining thermal power generation system remain open; Adjust the opening of the twelfth steam-water valve 6-12 and the thirteenth steam-water valve 6-13 to bring the cold-side flow rate into the module thermal storage device 20 to the set value; adjust the frequency of the molten salt pump 19 and the opening of the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, and the twenty-second steam-water valve 6-22 to bring the cold-side outlet temperature of the module thermal storage device 20 to the set value; adjust the opening of the fifteenth steam-water valve 6-15 and the sixteenth steam-water valve 6-16 to bring the cold-side flow rate into the energy release heat exchanger 30 to the set value; adjust the frequency of the high-temperature pump 29 to bring the cold-side outlet temperature of the energy release heat exchanger 30 to the set value. During the later stages of energy release, as the cold-side outlet temperature of the module thermal storage device 20 decreases, the eighteenth steam-water valve 6-18 is closed, the nineteenth steam-water valve 6-19 is opened, and the frequency of the molten salt pump 19, the opening of the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, and the twenty-second steam-water valve 6-22 are readjusted to bring the cold-side outlet temperature of the module thermal storage device 20 to a new set value.

[0049] The control logic for starting up a boiler in a multi-heat-source modular composite thermal storage system for a thermal power generation system is as follows; Start water pump 16, molten salt pump 19 and high temperature pump 29. Open the fourteenth steam-water valve 6-14, the twenty-eighth steam-water valve 6-28, the twenty-fifth steam-water valve 6-25, the twenty-third steam-water valve 6-23, the twentieth steam-water valve 6-20, the twenty-second steam-water valve 6-22, the seventeenth steam-water valve 6-17, the first steam-water valve 6-1, the second steam-water valve 6-2, and the third steam-water valve 6-3. Close the fourth steam-water valve 6-4, the thirteenth steam-water valve 6-13, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, the nineteenth steam-water valve 6-19, the twenty-first steam-water valve 6-21, the twenty-fourth steam-water valve 6-24, the twenty-sixth steam-water valve 6-26, and the twenty-seventh steam-water valve 6-27. Control the steam-water valves of the remaining thermal power generation system according to the conventional start-up procedure. Adjust the frequency of the start-up water pump 16 to make the steam flow rate entering the auxiliary steam header 8 reach the set value; adjust the frequency of the molten salt pump 19, the frequency of the high temperature pump 29, and the opening of the 20th steam-water valve 6-20 and the 22nd steam-water valve 6-22 to make the cold side outlet temperature of the module heat storage device 20 reach the set value. When the thermal power generation system is started, the feedwater from the deaerator 11 passes through the start-up water pump 16, the cold side of the energy release heat exchanger 30, the heat exchange pipe 23 of the module heat storage device 20, and the first steam-water separator 7 in sequence. The steam separated by the first steam-water separator 7 enters the auxiliary steam header 8 to supply the steam required for the start-up of the power generation system, and the separated condensate returns to the deaerator 11.

[0050] In addition to energy storage and energy release operations, multi-heat source modular composite thermal energy storage systems also have three other scenarios: short-term hot standby, short-term shutdown hot standby, and long-term shutdown cold standby. The control logic for these three scenarios is as follows. Short-term hot standby: When the time interval between the end of thermal storage operation and the start of energy release operation or the end of energy release operation and the start of energy storage operation is ≤48h, it is considered short-term hot standby. During the short-term hot standby period, no additional measures need to be taken for the multi-heat source modular composite thermal storage system. Short-term shutdown hot standby: When the time interval between the end of thermal storage operation and the start of energy release operation or the end of energy release operation and the start of energy storage operation is 48-480 hours, it is considered short-term shutdown hot standby. During the short-term shutdown hot standby period, 1-20 tons / day of hot steam must be introduced into the multi-heat source modular composite thermal storage system to maintain the hot standby status. When steam is supplied, molten salt pump 19 and cryogenic pump 26 operate at low power. The fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 are open. The first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, and the nineteenth steam-water valve 6-1... 9. The twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the twenty-third steam-water valve 6-23, the twenty-fifth steam-water valve 6-25, the twenty-sixth steam-water valve 6-26, and the twenty-eighth steam-water valve 6-28 are closed, while the remaining steam-water valves of the thermal power generation system remain open. When the heat storage medium in the cryogenic storage tank 27 is insufficient or the temperature is too low, the high-temperature pump 29 is activated to supplement it. Specifically, the external hot steam can come from the reheat steam of the thermal power generation system or steam from other sources added through the steam-water pipeline.

[0051] Long-term shutdown for cold standby: A period of >480 hours between the end of thermal storage operation and the start of energy release operation, or between the end of energy release operation and the start of energy storage operation, constitutes long-term shutdown for cold standby. During this period, no additional measures are required for the multi-source modular composite thermal storage system; the system gradually and naturally cools down and the molten salt solidifies. When restarting is required after the cold standby period, steam at a flow rate not exceeding 30% of the rated flow is introduced. Low-temperature pump 26 and high-temperature pump 26 are started, and the fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 are opened. The first steam-water valve 6- 1. The second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, the nineteenth steam-water valve 6-19, the twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the twenty-third steam-water valve 6-23, the twenty-fifth steam-water valve 6-25, the twenty-sixth steam-water valve 6-26, and the twenty-eighth steam-water valve are closed. The steam-water valves of the remaining thermal power generation system remain open until the temperature of the heat storage medium in the module heat storage device 20 is ≥20℃ higher than the melting point of the molten salt, at which point the system enters a short-term shutdown hot standby state.

[0052] Example 2 Please see Figure 2 This embodiment provides a multi-heat source modular composite thermal energy storage system coupled with thermal power, which includes a thermal power generation system and a multi-heat source modular composite thermal energy storage system. The thermal 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, multiple steam-water valves, a first steam-water separator 7, an auxiliary steam header 8, a high-temperature heater, a low-temperature heater, a deaerator 11, a feedwater pump 12, a condenser 13, a condensate pump 14, a shaft seal heater 15, and a steam-water pipeline 31. The multi-heat source modular composite thermal storage system includes a start-up water pump 16, a transformer 17, an electric heater 18, a molten salt pump 19, a modular thermal storage device 20, a second steam-water separator 24, an energy storage heat exchanger 25, a cryogenic pump 26, a cryogenic storage tank 27, a high-temperature storage tank 28, a high-temperature pump 29, an energy release heat exchanger 30, a steam-water pipeline 31, a molten salt pipeline 32, electrical wiring 33, and a steam-water valve 6. The modular thermal storage device 20 includes a modular thermal storage medium 21, an overflow pipe 22, and a heat exchange pipe 23.

[0053] The main steam outlet of the boiler 1 is connected to the high-pressure cylinder 2, the outlet of the high-pressure cylinder 2 is connected to the reheat steam inlet of the boiler 1, and the reheat steam outlet of the boiler 2 is connected in sequence to the intermediate-pressure cylinder 3 and the low-pressure cylinder 4 and drives the generator 5 to generate electricity. The outlet of the low-pressure cylinder 4 is connected in sequence to the condenser 13, condensate pump 14, shaft seal heater 15, low-temperature heater water side, deaerator 11, feed water pump 12, high-temperature heater water side and boiler 1 feed water inlet via steam-water pipeline 31. The steam-side inlets of the high-temperature heater and the low-temperature heater are respectively connected to the high-pressure cylinder 2, the intermediate-pressure cylinder 3 and / or the low-pressure cylinder 4, so as to use part of the steam in the turbine to heat the water-side working fluid of the high-temperature heater and the low-temperature heater. The deaerator 11 is connected to the outlet of the intermediate pressure cylinder 3. The condensate outlet of the first high temperature heater 9-1 is connected to the condensate inlet of the second high temperature heater 9-2 through the steam-water pipe 31. The condensate outlet of the second high temperature heater 9-2 is connected to the condensate inlet of the third high temperature heater 9-3 through the steam-water pipe 31. The condensate outlet of the third high temperature heater 9-3 is connected to the deaerator 11 through the steam-water pipe 31. The condensate outlet of the first low-temperature heater 10-1 is connected to the condensate inlet of the second low-temperature heater 10-2 through a steam-water pipe 31. The condensate outlet of the second low-temperature heater 10-2 is connected to the condensate inlet of the third low-temperature heater 10-3 through a steam-water pipe 31. The condensate outlet of the third low-temperature heater 10-3 is connected to the condenser 13 through a steam-water pipe 31. The steam outlet of the first steam-water separator 7 is connected to the auxiliary steam header 8, and the condensate outlet of the first steam-water separator 7 is connected to the deaerator 11. Steam and water valves are installed at each steam and water pipeline 31 in the thermal power generation system to control the opening and closing of each steam and water pipeline 31.

[0054] In the multi-heat source modular composite thermal storage system, the electric heater 18 is connected in sequence to the transformer 17 and the generator 5 in the thermal power generation system via electrical lines 33. The bottom module molten salt outlet of the modular thermal storage device 20 is connected to the molten salt pump 19 and the electric heater 18 in sequence through the molten salt pipe 32. The molten salt outlet of the electric heater 18 is connected to the top module of the modular thermal storage device 20. The heat exchange pipe 23 of the modular thermal storage device 20 is connected to the water-side outlet of the first high-temperature heater 9-1, the water-side outlet of the second high-temperature heater 9-2, and the water-side inlet of the second high-temperature heater 9-2 of the thermal power generation system through the steam-water pipe 31. The heat exchange pipe 23 of the modular thermal storage device 20 is connected to the reheat steam outlet of the boiler 1 of the thermal power generation system through the steam-water pipe 31. The heat exchange pipe 23 of the modular thermal storage device 20 is connected to the inlet of the second steam-water separator 24 through the steam-water pipe 31. The outlet of the second steam-water separator 24 is sequentially connected to the hot side inlet of the energy storage heat exchanger 25 and the water side inlet of the first low-temperature heater 10-1; the cold side inlet of the energy release heat exchanger 30 is connected to the water side inlet of the third low-temperature heater 10-3, and the cold side outlet of the energy release heat exchanger 30 is connected to the water side outlet of the first low-temperature heater 10-1; the outlet of the low-temperature pump 26 is sequentially connected to the cold side of the energy storage heat exchanger 25, the high-temperature storage tank 28, the high-temperature pump 29, the hot side of the energy release heat exchanger 30, and the inlet of the low-temperature storage tank 27, and the outlet of the low-temperature storage tank 27 is connected to the inlet of the low-temperature pump 26; and the steam-water valves are arranged at each steam-water pipeline 31 of the multi-heat source modular composite thermal energy storage system to control the opening and closing of each steam-water pipeline 31.

[0055] In this embodiment, the modular thermal storage device 20 is divided into 16 parallel modular thermal storage units, and the connection method of the parallel pipelines is described in [reference needed]. Figure 4 Multiple of the aforementioned module thermal storage units are connected in parallel via steam-water pipes 31; A single module thermal storage unit connects the molten salts in the five thermal storage modules in series through an overflow pipe 22; the module thermal storage unit connects the heat exchange pipes 23 in the five thermal storage modules in series through an external steam-water pipe 31; the module thermal storage device 20 has two heating methods: electric heat source and steam heat source, and the two methods can be operated independently or in combination.

[0056] The bottom module inlet of the modular thermal storage unit is connected to the steam and water pipe 31, which is connected to the top module outlet via the twenty-second steam and water valve 6-22. The second module outlet of the modular thermal storage unit is connected to the steam and water pipe 31, which is connected to the top module outlet via the external steam and water pipe 31 and the twenty-first steam and water valve 6-21, from bottom to top.

[0057] The heat exchange pipe 23 of the modular heat storage device 20 is connected to the water-side outlet of the first high-temperature heater 9-1, the water-side outlet of the second high-temperature heater 9-2, and the water-side inlet of the second high-temperature heater 9-2 through the steam-water pipe 31. The top module is connected to the water-side outlet of the first high-temperature heater 9-1 and the water-side outlet of the second high-temperature heater 9-2 through the eighteenth steam-water valve 6-18 and the nineteenth steam-water valve 6-19. The bottom module is connected to the water-side inlet of the second high-temperature heater 9-2 through the thirteenth steam-water valve 6-13.

[0058] The connection position between the hot side outlet of the energy storage heat exchanger 25 and the water side of the low-temperature heater 10 is determined according to the temperature matching principle, and the hot side outlet of the energy storage heat exchanger 25 is connected to the water side outlet of the second low-temperature heater 10-2.

[0059] The multi-heat-source modular composite thermal energy storage system can be used as a start-up boiler for a thermal power generation system. The heat exchange pipe 23 of the modular thermal energy storage device 20 is connected to the inlet of the first steam-water separator 7 of the thermal power generation system through the steam-water pipe 31. The heat exchange pipe 23 of the modular thermal energy storage device 20 is connected to the cold side outlet of the energy release heat exchanger 30 through the steam-water pipe 31 and the twenty-fifth steam-water valve 6-25. The cold side inlet of the energy release heat exchanger 30 is connected in sequence to the start-up water pump 16 and the outlet of the deaerator 11 of the thermal power generation system.

[0060] The heat storage medium 21 of the modular heat storage device 20 is molten salt; the heat storage medium in the low temperature tank 27 and the high temperature tank 28 is water.

[0061] Specifically, the inlet of the first steam-water separator 7 is equipped with a first steam-water valve 6-1; the steam outlet of the first steam-water separator 7 is connected to the auxiliary steam header via a second steam-water valve 6-2; the condensate outlet of the first steam-water separator 7 is connected to the deaerator via a third steam-water valve 6-3; and a fourth steam-water valve 6-4 is provided on the steam-water pipeline 31 connecting the cold side outlet of the module heat storage device 20 to the inlet of the intermediate-pressure cylinder 3. The outlet of the high-pressure cylinder 2 is connected to the first high-pressure cylinder 2 via a fifth steam-water valve 6-5 and a sixth steam-water valve 6-6, respectively. The steam-side inlets of the high-temperature heater 9-1 and the second high-temperature heater 9-2 are connected to the steam-side inlet of the third high-temperature heater 9-3, the deaerator 11, and the steam-side inlet of the first low-temperature heater 10-1 via the seventh steam-water valve 6-7, the eighth steam-water valve 6-8, and the ninth steam-water valve 6-9, respectively. The outlet of the low-pressure cylinder 4 is also connected to the steam-side inlets of the second low-temperature heater 10-2 and the third low-temperature heater 10-3 via the tenth steam-water valve 6-10 and the eleventh steam-water valve 6-11. The outlet of the water pump 12 is connected to the water-side inlet of the third high-temperature heater 9-3 and the cold-side inlet of the module heat storage device 20 through the 12th steam-water valve 6-12 and the 13th steam-water valve 6-13, respectively. A 23rd steam-water valve 6-23 is also provided between the 13th steam-water valve 6-13 and the cold-side inlet of the module heat storage device 20. The deaerator 11 is connected to the start-up water pump 16 through the 14th steam-water valve 6-14. The shaft seal heater 15 is connected to the water-side inlet of the third low-temperature heater 10-3 and the cold-side inlet of the energy release heat exchanger 30 through the 15th steam-water valve 6-15 and the 16th steam-water valve 6-16, respectively. The start-up water pump 16 is connected to the cold-side inlet of the energy release heat exchanger 30 through the 28th steam-water valve 6-28. The cold side outlet of the modular thermal storage device 20 is provided with a twentieth steam-water valve 6-20, and the outlet of the twentieth steam-water valve 6-20 is connected to the first steam-water valve 6-1 and the fourth steam-water valve 6-4, the water inlet of the boiler 1, and the water side inlet of the first high-temperature heater 9-1 through the seventeenth steam-water valve 6-17, the eighteenth steam-water valve 6-18, and the nineteenth steam-water valve 6-19, respectively. The module heat storage device 20 is provided with a twenty-fourth steam-water valve 6-24 at the cold side inlet, which is connected to the steam-water inlet of the second steam-water separator 24. The cold side outlet of the energy release heat exchanger 30 is connected to the cold side inlet of the module heat storage device 20 and the inlet of the deaerator 11 through the twenty-fifth steam-water valve 6-25 and the twenty-fifth steam-water valve 6-26, respectively. The energy storage heat exchanger 25 is provided with a twenty-seventh steam-water valve 6-27 at the hot side outlet.

[0062] For the energy storage stage, the control logic of the multi-heat source modular composite thermal energy storage system coupled with thermal power is divided into three modes: electric energy storage, steam energy storage, and electric-steam hybrid energy storage. Electric energy storage mode: Molten salt pump 19 starts, generator 5 provides electrical energy which is transmitted to electric heater 18 via transformer 17 to generate heat. The frequency of molten salt pump 19 and the power of electric heater 18 are adjusted according to the preset molten salt outlet temperature until the set load requirement is reached; the steam and water valves 1-1, 6-2, 6-3, 6-4, 6-13, 6-14, 6-16, and 6-17 are closed. Steam and water valves 6-17, 6-18, 6-19, 6-20, 6-21, 6-22, 6-23, 6-24, 6-25, 6-26, 6-27, and 6-28 of the 24th and 25th steam and water valves of the 26th and 27th steam and water valves of the 28th steam and water valves of the thermal power generation system shall remain open. Molten salt flows from the bottom module of the modular thermal storage device 20 through the molten salt pump 19 and the electric heater 18 to the top module. The molten salt in the top module flows down to the bottom module through the overflow pipe 22, so that the entire modular thermal storage device 20 can store energy.

[0063] Steam energy storage mode: Molten salt pump 19 and cryogenic pump 26 are started, the fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 are opened, and the first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, and the nineteenth steam-water valve are opened. Water valve 6-19, steam-water valve 6-21 (21st), steam-water valve 6-22 (22nd), steam-water valve 6-23 (23rd), steam-water valve 6-25 (25th), steam-water valve 6-26 (26th), and steam-water valve 6-28 (28th) are closed, while the steam-water valves of the remaining thermal power generation system remain open; the opening of steam-water valve 6-27 (27th), the frequency of molten salt pump 19, and the cryogenic pump 26 are adjusted to bring the hot-side outlet temperature and flow rate of the module thermal storage device 20 and the energy storage heat exchanger 25 to the set values; Steam from the thermal power generation system first enters the module thermal storage device 20 through the steam-water pipeline 31 containing the fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, and the twentieth steam-water valve 6-20. Then, the separated steam and condensate are fed into the hot-side steam inlet and hot-side condensate inlet of the energy storage heat exchanger 25, respectively, to heat the thermal storage medium from the cryogenic storage tank 27. Finally, the condensate from the hot-side outlet of the energy storage heat exchanger 25 returns to the water side of the cryogenic heater 10 of the thermal power generation system.

[0064] Electric-steam hybrid energy storage mode: Molten salt pump 19 and cryogenic pump 26 are started. Generator 5 provides electrical energy, which is transmitted to electric heater 18 via transformer 17 to generate heat. The fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 are opened. The first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, and the nineteenth steam-water valve are opened. Water valve 6-19, steam-water valve 6-21 (21st), steam-water valve 6-22 (22nd), steam-water valve 6-23 (23rd), steam-water valve 6-25 (25th), steam-water valve 6-26 (26th), and steam-water valve 6-28 (28th) are closed, while the steam-water valves of the remaining thermal power generation system remain open. The power of electric heater 18, the opening degree of steam-water valve 6-27 (27th), and the frequency of molten salt pump 19 and cryogenic pump 26 are adjusted to bring the hot-side outlet temperature and flow rate of module thermal storage device 20 and energy storage heat exchanger 25 to the set values, while simultaneously constraining the molten salt outlet temperature of electric heater 18 to prevent overheating.

[0065] For the energy release phase, the control logic of the multi-heat source modular composite thermal storage system coupled with thermal power is divided into three modes: heating high-pressure feedwater, heating low-pressure feedwater, and heating both high-pressure and low-pressure feedwater. High-temperature heater feedwater mode: Molten salt pump 19 starts, and during the initial energy release phase, the 12th steam-water valve 6-12, the 13th steam-water valve 6-13, the 23rd steam-water valve 6-23, the 20th steam-water valve 6-20, the 21st steam-water valve 6-21, the 22nd steam-water valve 6-22, and the 18th steam-water valve 6-18 are opened. The 1st steam-water valve 6-1, the 2nd steam-water valve 6-2, the 3rd steam-water valve 6-3, the 4th steam-water valve 6-4, the 14th steam-water valve 6-14, the 16th steam-water valve 6-16, the 17th steam-water valve 6-17, the 19th steam-water valve 6-19, the 24th steam-water valve 6-24, the 25th steam-water valve 6-25, the 26th steam-water valve 6-26, the 27th steam-water valve 6-27, and the 28th steam-water valve 6-28 are closed. The steam-water valves of the remaining thermal power generation system remain open. Adjust the opening of the twelfth steam-water valve 6-12 and the thirteenth steam-water valve 6-13 to make the cold side flow rate entering the module heat storage device 20 reach the set value; Adjust the frequency of molten salt pump 19, the opening of the 20th steam-water valve 6-20, the 21st steam-water valve 6-21, and the 22nd steam-water valve 6-22 to make the cold side outlet temperature of the module thermal storage device 20 reach the set value. During the later stages of energy release, as the cold-side outlet temperature of the module thermal storage device 20 decreases, the eighteenth steam-water valve 6-18 is closed, the nineteenth steam-water valve 6-19 is opened, and the frequency of the molten salt pump 19, the opening of the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, and the twenty-second steam-water valve 6-22 are readjusted to bring the cold-side outlet temperature of the module thermal storage device 20 to a new set value.

[0066] Heating low-temperature heater feedwater mode: High-temperature pump 29 starts, the fifteenth steam-water valve 6-15, the sixteenth steam-water valve 6-16, and the twenty-sixth steam-water valve 6-26 are opened, the first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the fourth steam-water valve 6-4, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the seventeenth steam-water valve 6-17, the eighteenth steam-water valve 6-18, the nineteenth steam-water valve 6-19, the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the twenty-third steam-water valve 6-23, the twenty-fourth steam-water valve 6-24, the twenty-fifth steam-water valve 6-25, the twenty-seventh steam-water valve 6-27, and the twenty-eighth steam-water valve 6-28 are closed, and the steam-water valves of the remaining thermal power generation system remain open; Adjust the opening of the fifteenth steam-water valve 6-15 and the sixteenth steam-water valve 6-16 to make the cold side flow rate entering the energy release heat exchanger 30 reach the set value; adjust the frequency of the high temperature pump 29 to make the cold side outlet temperature of the energy release heat exchanger 30 reach the set value.

[0067] Heating high and low temperature heater feedwater mode: Molten salt pump 19 and high temperature pump 29 are started, the thirteenth steam-water valve 6-13, the twenty-third steam-water valve 6-23, the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the eighteenth steam-water valve 6-18, the sixteenth steam-water valve 6-16, and the twenty-sixth steam-water valve 6-26 mentioned in the energy release phase are opened, the first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the fourth steam-water valve 6-4, the fourteenth steam-water valve 6-14, the seventeenth steam-water valve 6-17, the nineteenth steam-water valve 6-19, the twenty-fourth steam-water valve 6-24, the twenty-fifth steam-water valve 6-25, the twenty-seventh steam-water valve 6-27, and the twenty-eighth steam-water valve 6-28 are closed, and the steam-water valves of the remaining thermal power generation system remain open; Adjust the opening of the twelfth steam-water valve 6-12 and the thirteenth steam-water valve 6-13 to bring the cold-side flow rate into the module thermal storage device 20 to the set value; adjust the frequency of the molten salt pump 19 and the opening of the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, and the twenty-second steam-water valve 6-22 to bring the cold-side outlet temperature of the module thermal storage device 20 to the set value; adjust the opening of the fifteenth steam-water valve 6-15 and the sixteenth steam-water valve 6-16 to bring the cold-side flow rate into the energy release heat exchanger 30 to the set value; adjust the frequency of the high-temperature pump 29 to bring the cold-side outlet temperature of the energy release heat exchanger 30 to the set value. During the later stages of energy release, as the cold-side outlet temperature of the module thermal storage device 20 decreases, the eighteenth steam-water valve 6-18 is closed, the nineteenth steam-water valve 6-19 is opened, and the frequency of the molten salt pump 19, the opening of the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, and the twenty-second steam-water valve 6-22 are readjusted to bring the cold-side outlet temperature of the module thermal storage device 20 to a new set value.

[0068] The control logic for starting up a boiler in a multi-heat-source modular composite thermal storage system for a thermal power generation system is as follows; Start water pump 16, molten salt pump 19 and high temperature pump 29. Open the fourteenth steam-water valve 6-14, the twenty-eighth steam-water valve 6-28, the twenty-fifth steam-water valve 6-25, the twenty-third steam-water valve 6-23, the twentieth steam-water valve 6-20, the twenty-second steam-water valve 6-22, the seventeenth steam-water valve 6-17, the first steam-water valve 6-1, the second steam-water valve 6-2, and the third steam-water valve 6-3. Close the fourth steam-water valve 6-4, the thirteenth steam-water valve 6-13, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, the nineteenth steam-water valve 6-19, the twenty-first steam-water valve 6-21, the twenty-fourth steam-water valve 6-24, the twenty-sixth steam-water valve 6-26, and the twenty-seventh steam-water valve 6-27. Control the steam-water valves of the remaining thermal power generation system according to the conventional start-up procedure. Adjust the frequency of the start-up water pump 16 to make the steam flow rate entering the auxiliary steam header 8 reach the set value; adjust the frequency of the molten salt pump 19, the frequency of the high temperature pump 29, and the opening of the 20th steam-water valve 6-20 and the 22nd steam-water valve 6-22 to make the cold side outlet temperature of the module heat storage device 20 reach the set value. When the thermal power generation system is started, the feedwater from the deaerator 11 passes through the start-up water pump 16, the cold side of the energy release heat exchanger 30, the heat exchange pipe 23 of the module heat storage device 20, and the first steam-water separator 7 in sequence. The steam separated by the first steam-water separator 7 enters the auxiliary steam header 8 to supply the steam required for the start-up of the power generation system, and the separated condensate returns to the deaerator 11.

[0069] In addition to energy storage operation and energy release operation, the multi-heat source modular composite thermal storage system has three scenarios: short-term hot standby, short-term shutdown hot standby, and long-term shutdown cold standby. The control logic for the three scenarios is as follows. Short-term hot standby: When the time interval between the end of thermal storage operation and the start of energy release operation or the end of energy release operation and the start of energy storage operation is ≤48h, it is considered short-term hot standby. During the short-term hot standby period, no additional measures need to be taken for the multi-heat source modular composite thermal storage system. Short-term shutdown hot standby: When the time interval between the end of thermal storage operation and the start of energy release operation or the end of energy release operation and the start of energy storage operation is 48-480 hours, it is considered short-term shutdown hot standby. During the short-term shutdown hot standby period, 1-20 tons / day of hot steam must be introduced into the multi-heat source modular composite thermal storage system to maintain the hot standby status. When steam is supplied, molten salt pump 19 and cryogenic pump 26 operate at low power. The fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 are open. The first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, and the nineteenth steam-water valve 6-1... 9. The twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the twenty-third steam-water valve 6-23, the twenty-fifth steam-water valve 6-25, the twenty-sixth steam-water valve 6-26, and the twenty-eighth steam-water valve 6-28 are closed, while the remaining steam-water valves of the thermal power generation system remain open. When the heat storage medium in the cryogenic storage tank 27 is insufficient or the temperature is too low, the high-temperature pump 29 is activated to supplement it. Specifically, the external hot steam can come from the reheat steam of the thermal power generation system or steam from other sources added through the steam-water pipeline.

[0070] Long-term shutdown for cold standby: A period of >480 hours between the end of thermal storage operation and the start of energy release operation, or between the end of energy release operation and the start of energy storage operation, constitutes long-term shutdown for cold standby. During this period, no additional measures are required for the multi-source modular composite thermal storage system; the system gradually and naturally cools down and the molten salt solidifies. When restarting is required after the cold standby period, steam at a flow rate not exceeding 30% of the rated flow is introduced. Low-temperature pump 26 and high-temperature pump 26 are started, and the fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 are opened. The first steam-water valve 6- 1. The second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, the nineteenth steam-water valve 6-19, the twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the twenty-third steam-water valve 6-23, the twenty-fifth steam-water valve 6-25, the twenty-sixth steam-water valve 6-26, and the twenty-eighth steam-water valve are closed. The steam-water valves of the remaining thermal power generation system remain open until the temperature of the heat storage medium in the module heat storage device 20 is ≥20℃ higher than the melting point of the molten salt, at which point the system enters a short-term shutdown hot standby state.

[0071] Example 3 Please see Figure 3 This embodiment provides a multi-heat source modular composite thermal energy storage system coupled with thermal power, including a thermal power generation system and a multi-heat source modular composite thermal energy storage system; The thermal 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, multiple steam-water valves, a first steam-water separator 7, an auxiliary steam header 8, a high-temperature heater, a low-temperature heater, a deaerator 11, a feedwater pump 12, a condenser 13, a condensate pump 14, a shaft seal heater 15, and a steam-water pipeline 31. The multi-heat source modular composite thermal storage system includes a start-up water pump 16, a transformer 17, an electric heater 18, a molten salt pump 19, a modular thermal storage device 20, a second steam-water separator 24, an energy storage heat exchanger 25, a cryogenic pump 26, a cryogenic storage tank 27, a high-temperature storage tank 28, a high-temperature pump 29, an energy release heat exchanger 30, a steam-water pipeline 31, a molten salt pipeline 32, electrical wiring 33, and a steam-water valve 6. The modular thermal storage device 20 includes a modular thermal storage medium 21, an overflow pipe 22, and a heat exchange pipe 23.

[0072] The main steam outlet of the boiler 1 is connected to the high-pressure cylinder 2, the outlet of the high-pressure cylinder 2 is connected to the reheat steam inlet of the boiler 1, and the reheat steam outlet of the boiler 2 is connected in sequence to the intermediate-pressure cylinder 3 and the low-pressure cylinder 4 and drives the generator 5 to generate electricity. The outlet of the low-pressure cylinder 4 is connected in sequence to the condenser 13, condensate pump 14, shaft seal heater 15, low-temperature heater water side, deaerator 11, feed water pump 12, high-temperature heater water side and boiler 1 feed water inlet via steam-water pipeline 31. The steam-side inlets of the high-temperature heater and the low-temperature heater are respectively connected to the high-pressure cylinder 2, the intermediate-pressure cylinder 3 and / or the low-pressure cylinder 4, so as to use part of the steam in the turbine to heat the water-side working fluid of the high-temperature heater and the low-temperature heater. The deaerator 11 is connected to the outlet of the intermediate pressure cylinder 3. The condensate outlet of the first high temperature heater 9-1 is connected to the condensate inlet of the second high temperature heater 9-2 through the steam-water pipe 31. The condensate outlet of the second high temperature heater 9-2 is connected to the condensate inlet of the third high temperature heater 9-3 through the steam-water pipe 31. The condensate outlet of the third high temperature heater 9-3 is connected to the deaerator 11 through the steam-water pipe 31. The condensate outlet of the first cryogenic heater 10-1 is connected to the condensate inlet of the second cryogenic heater 10-2 via a steam-water pipe 31. The condensate outlet of the second cryogenic heater 10-2 is connected to the condensate inlet of the third cryogenic heater 10-3 via a steam-water pipe 31. The condensate outlet of the third cryogenic heater 10-3 is connected to the condensate inlet of the fourth cryogenic heater 10-4 via a steam-water pipe 31. The condensate outlet of the fourth cryogenic heater 10-4 is connected to the condenser 13 via a steam-water pipe 31. The steam outlet of the first steam-water separator 7 is connected to the auxiliary steam header 8. The condensate outlet of the first steam-water separator 7 is connected to the deaerator 11. Steam-water valves are arranged at each steam-water pipe 31 in the thermal power generation system to control the opening and closing of each steam-water pipe 31.

[0073] In the multi-heat source modular composite thermal storage system, the electric heater 18 is connected in sequence to the transformer 17 and the generator 5 in the thermal power generation system via electrical lines 33. The bottom module molten salt outlet of the modular thermal storage device 20 is connected to the molten salt pump 19 and the electric heater 18 in sequence through the molten salt pipe 32. The molten salt outlet of the electric heater 18 is connected to the top module of the modular thermal storage device 20. The heat exchange pipe 23 of the modular thermal storage device 20 is connected to the water-side outlet of the second high-temperature heater 9-2, the water-side outlet of the third high-temperature heater 9-3 and the water-side inlet of the third high-temperature heater 9-3 of the thermal power generation system through the steam-water pipe 31. The heat exchange pipe 23 of the modular thermal storage device 20 is connected to the reheat steam outlet of the boiler 1 of the thermal power generation system through the steam-water pipe 31. The heat exchange pipe 23 of the modular heat storage device 20 is connected to the inlet of the second steam-water separator 24 via the steam-water pipe 31. The outlet of the second steam-water separator 24 is sequentially connected to the hot-side inlet of the energy storage heat exchanger 25 and the water-side outlet of the second cryogenic heater 10-2; the cold-side inlet of the energy release heat exchanger 30 is connected to the water-side inlet of the third cryogenic heater 10-3, and the cold-side outlet of the energy release heat exchanger 30 is connected to the water-side outlet of the second cryogenic heater 10-2; the outlet of the cryogenic pump 26 is sequentially connected to the cold side of the energy storage heat exchanger 25, the high-temperature storage tank 28, the high-temperature pump 29, the hot side of the energy release heat exchanger 30, and the inlet of the cryogenic storage tank 27, and the outlet of the cryogenic storage tank 27 is connected to the inlet of the cryogenic pump 26; the steam-water valve 6 is arranged at each of the steam-water pipelines 31 in the multi-heat source modular composite thermal energy storage system.

[0074] The modular thermal storage device 20 is divided into 18 parallel modular thermal storage units. The connection method of the parallel pipelines is described in [reference needed]. Figure 4 Multiple of the aforementioned module thermal storage units are connected in parallel via steam-water pipes 31; A single module thermal storage unit connects the molten salts in the five thermal storage modules in series through an overflow pipe 22; the module thermal storage unit connects the heat exchange pipes 23 in the five thermal storage modules in series through an external steam-water pipe 31; the module thermal storage device 20 has two heating methods: electric heat source and steam heat source, and the two methods can be operated independently or in combination.

[0075] The bottom module inlet of the modular thermal storage unit is connected to the steam and water pipe 31, which is connected to the top module outlet via the twenty-second steam and water valve 6-22. The second module outlet of the modular thermal storage unit is connected to the steam and water pipe 31, which is connected to the top module outlet via the external steam and water pipe 31 and the twenty-first steam and water valve 6-21, from bottom to top.

[0076] The heat exchange pipe 23 of the modular heat storage device 20 is connected to the water-side outlet of the first high-temperature heater 9-1, the water-side outlet of the second high-temperature heater 9-2, and the water-side inlet of the second high-temperature heater 9-2 through the steam-water pipe 31. The top module is connected to the water-side outlet of the first high-temperature heater 9-1 and the water-side outlet of the second high-temperature heater 9-2 through the eighteenth steam-water valve 6-18 and the nineteenth steam-water valve 6-19. The bottom module is connected to the water-side inlet of the second high-temperature heater 9-2 through the thirteenth steam-water valve 6-13.

[0077] The connection position between the hot side outlet of the energy storage heat exchanger 25 and the water side of the low-temperature heater is determined according to the temperature matching principle, and the hot side outlet of the energy storage heat exchanger 25 is connected to the water side outlet of the second low-temperature heater 10-2.

[0078] The multi-heat-source modular composite thermal energy storage system can be used as a start-up boiler for a thermal power generation system. The heat exchange pipe 23 of the modular thermal energy storage device 20 is connected to the inlet of the first steam-water separator 7 of the thermal power generation system through the steam-water pipe 31. The heat exchange pipe 23 of the modular thermal energy storage device 20 is connected to the cold side outlet of the energy release heat exchanger 30 through the steam-water pipe 31 and the twenty-fifth steam-water valve 6-25. The cold side inlet of the energy release heat exchanger 30 is connected in sequence to the start-up water pump 16 and the outlet of the deaerator 11 of the thermal power generation system.

[0079] The heat storage medium 21 of the modular heat storage device 20 adopts a composite heat storage of molten salt and solid heat storage medium; the heat storage medium in the low temperature tank 27 and the high temperature tank 28 is heat transfer oil.

[0080] Specifically, the inlet of the first steam-water separator 7 is equipped with a first steam-water valve 6-1, the steam outlet of the first steam-water separator 7 is connected to the auxiliary steam header through a second steam-water valve 6-2, the condensate outlet of the first steam-water separator 7 is connected to the deaerator through a third steam-water valve 6-3, and a fourth steam-water valve 6-4 is provided on the steam-water pipeline 31 connecting the cold side outlet of the module heat storage device 20 to the inlet of the intermediate pressure cylinder 3. The outlet of the high pressure cylinder 2 is connected to the first high-temperature heater 9-1 and the second high-temperature heater through a fifth steam-water valve 6-5 and a sixth steam-water valve 6-6, respectively. The steam-side inlet of the device 9-2, the outlet of the intermediate-pressure cylinder 3 is connected to the steam-side inlet of the third high-temperature heater 9-3, the deaerator 11 and the steam-side inlet of the first low-temperature heater 10-1 respectively through the seventh steam-water valve 6-7, the eighth steam-water valve 6-8 and the ninth steam-water valve 6-9, and the outlet of the low-pressure cylinder 4 is also connected to the steam-side inlet of the second low-temperature heater 10-2, the third low-temperature heater 10-3 and the fourth low-temperature heater 10-4 through the tenth steam-water valve 6-10, the eleventh steam-water valve 6-11 and the twenty-ninth steam-water valve 6-29. The outlet of the water pump 12 is connected to the water-side inlet of the third high-temperature heater 9-3 and the cold-side inlet of the module heat storage device 20 through the 12th steam-water valve 6-12 and the 13th steam-water valve 6-13, respectively. A 23rd steam-water valve 6-23 is also provided between the 13th steam-water valve 6-13 and the cold-side inlet of the module heat storage device 20. The deaerator 11 is connected to the start-up water pump 16 through the 14th steam-water valve 6-14. The shaft seal heater 15 is connected to the water-side inlet of the third low-temperature heater 10-3 and the cold-side inlet of the energy release heat exchanger 30 through the 15th steam-water valve 6-15 and the 16th steam-water valve 6-16, respectively. The start-up water pump 16 is connected to the cold-side inlet of the energy release heat exchanger 30 through the 28th steam-water valve 6-28. The cold side outlet of the module thermal storage device 20 is provided with a twentieth steam-water valve 6-20, and the outlet of the twentieth steam-water valve 6-20 is connected to the water side inlet of the first steam-water valve 6-1, the fourth steam-water valve 6-4, the first high-temperature heater 9-1, and the second high-temperature heater 9-2 through the seventeenth steam-water valve 6-17, the eighteenth steam-water valve 6-18, and the nineteenth steam-water valve 6-19, respectively. The module heat storage device 20 is provided with a twenty-fourth steam-water valve 6-24 at the cold side inlet, which is connected to the steam-water inlet of the second steam-water separator 24. The cold side outlet of the energy release heat exchanger 30 is connected to the cold side inlet of the module heat storage device 20 and the water side inlet of the first low temperature heater 10-1 through the twenty-fifth steam-water valve 6-25 and the twenty-fifth steam-water valve 6-26, respectively. The energy storage heat exchanger 25 is provided with a twenty-seventh steam-water valve 6-27 at the hot side outlet.

[0081] For the energy storage stage, the control logic of the multi-heat source modular composite thermal energy storage system coupled with thermal power is divided into three modes: electric energy storage, steam energy storage, and electric-steam hybrid energy storage. Electric energy storage mode: Molten salt pump 19 starts, generator 5 provides electrical energy which is transmitted to electric heater 18 via transformer 17 to generate heat. The frequency of molten salt pump 19 and the power of electric heater 18 are adjusted according to the preset molten salt outlet temperature until the set load requirement is reached; the steam and water valves 1-1, 6-2, 6-3, 6-4, 6-13, 6-14, 6-16, and 6-17 are closed. Steam and water valves 6-17, 6-18, 6-19, 6-20, 6-21, 6-22, 6-23, 6-24, 6-25, 6-26, 6-27, and 6-28 of the 24th and 25th steam and water valves of the 26th and 27th steam and water valves of the 28th steam and water valves of the thermal power generation system shall remain open. Molten salt flows from the bottom module of the modular thermal storage device 20 through the molten salt pump 19 and the electric heater 18 to the top module. The molten salt in the top module flows down to the bottom module through the overflow pipe 22, so that the entire modular thermal storage device 20 can store energy.

[0082] Steam energy storage mode: Molten salt pump 19 and cryogenic pump 26 are started, the fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 are opened, the first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, the nineteenth steam-water valve 6-19, the twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the twenty-third steam-water valve 6-23, the twenty-fifth steam-water valve 6-25, the twenty-sixth steam-water valve 6-26, and the twenty-eighth steam-water valve 6-28 are closed, and the steam-water valves of the remaining thermal power generation system remain open; Adjust the opening of the twenty-seventh steam-water valve 6-27, the frequency of the molten salt pump 19 and the cryogenic pump 26 to make the hot-side outlet temperature and flow rate of the modular thermal storage device 20 and the energy storage heat exchanger 25 reach the set values; the steam from the thermal power generation system first enters the modular thermal storage device 20, and then the separated steam and condensate are introduced into the hot-side steam inlet and hot-side condensate inlet of the energy storage heat exchanger 25 respectively to heat the thermal storage medium from the cryogenic storage tank 27. Finally, the condensate at the hot-side outlet of the energy storage heat exchanger 25 returns to the water side of the cryogenic heater 10 of the thermal power generation system.

[0083] Electric-steam hybrid energy storage mode: Molten salt pump 19 and cryogenic pump 26 start; generator 5 provides electrical energy, which is transmitted to electric heater 18 via transformer 17 to generate heat; the fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 open; the first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, and the tenth... Steam-water valves 6-19 (number nine), 6-21 (number twenty-one), 6-22 (number twenty-two), 6-23 (number twenty-three), 6-25 (number twenty-five), 6-26 (number twenty-six), and 6-28 (number twenty-eight) are closed, while the remaining steam-water valves of the thermal power generation system remain open. The power of electric heater 18, the opening of steam-water valve 6-27 (number twenty-seven), and the frequencies of molten salt pump 19 and cryogenic pump 26 are adjusted to bring the hot-side outlet temperature and flow rate of module thermal storage device 20 and energy storage heat exchanger 25 to the set values, while simultaneously limiting the molten salt outlet temperature of electric heater 18 to prevent overheating.

[0084] For the energy release phase, the control logic of the multi-heat source modular composite thermal storage system coupled with thermal power is divided into three modes: heating high-pressure feedwater, heating low-pressure feedwater, and heating both high-pressure and low-pressure feedwater. High-temperature heater feedwater mode: Molten salt pump 19 starts, and during the initial energy release phase, the 12th steam-water valve 6-12, the 13th steam-water valve 6-13, the 23rd steam-water valve 6-23, the 20th steam-water valve 6-20, the 21st steam-water valve 6-21, the 22nd steam-water valve 6-22, and the 18th steam-water valve 6-18 are opened. The 1st steam-water valve 6-1, the 2nd steam-water valve 6-2, the 3rd steam-water valve 6-3, the 4th steam-water valve 6-4, the 14th steam-water valve 6-14, the 16th steam-water valve 6-16, the 17th steam-water valve 6-17, the 19th steam-water valve 6-19, the 24th steam-water valve 6-24, the 25th steam-water valve 6-25, the 26th steam-water valve 6-26, the 27th steam-water valve 6-27, and the 28th steam-water valve 6-28 are closed. The steam-water valves of the remaining thermal power generation system remain open. Adjust the opening of the twelfth steam-water valve 6-12 and the thirteenth steam-water valve 6-13 to make the cold side flow rate entering the module heat storage device 20 reach the set value; Adjust the frequency of molten salt pump 19, the opening of the 20th steam-water valve 6-20, the 21st steam-water valve 6-21, and the 22nd steam-water valve 6-22 to make the cold side outlet temperature of the module thermal storage device 20 reach the set value. During the later stages of energy release, as the cold-side outlet temperature of the module thermal storage device 20 decreases, the eighteenth steam-water valve 6-18 is closed, the nineteenth steam-water valve 6-19 is opened, and the frequency of the molten salt pump 19, the opening of the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, and the twenty-second steam-water valve 6-22 are readjusted to bring the cold-side outlet temperature of the module thermal storage device 20 to a new set value.

[0085] Heating low-temperature heater feedwater mode: High-temperature pump 29 starts, the fifteenth steam-water valve 6-15, the sixteenth steam-water valve 6-16, and the twenty-sixth steam-water valve 6-26 are opened, the first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the fourth steam-water valve 6-4, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the seventeenth steam-water valve 6-17, the eighteenth steam-water valve 6-18, the nineteenth steam-water valve 6-19, the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the twenty-third steam-water valve 6-23, the twenty-fourth steam-water valve 6-24, the twenty-fifth steam-water valve 6-25, the twenty-seventh steam-water valve 6-27, and the twenty-eighth steam-water valve 6-28 are closed, and the steam-water valves of the remaining thermal power generation system remain open; Adjust the opening of the fifteenth steam-water valve 6-15 and the sixteenth steam-water valve 6-16 to make the cold side flow rate entering the energy release heat exchanger 30 reach the set value; adjust the frequency of the high temperature pump 29 to make the cold side outlet temperature of the energy release heat exchanger 30 reach the set value.

[0086] Heating high and low temperature heater feedwater mode: Molten salt pump 19 and high temperature pump 29 are started, the thirteenth steam-water valve 6-13, the twenty-third steam-water valve 6-23, the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the eighteenth steam-water valve 6-18, the sixteenth steam-water valve 6-16, and the twenty-sixth steam-water valve 6-26 mentioned in the energy release phase are opened, the first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the fourth steam-water valve 6-4, the fourteenth steam-water valve 6-14, the seventeenth steam-water valve 6-17, the nineteenth steam-water valve 6-19, the twenty-fourth steam-water valve 6-24, the twenty-fifth steam-water valve 6-25, the twenty-seventh steam-water valve 6-27, and the twenty-eighth steam-water valve 6-28 are closed, and the steam-water valves of the remaining thermal power generation system remain open; Adjust the opening of the twelfth steam-water valve 6-12 and the thirteenth steam-water valve 6-13 to bring the cold-side flow rate into the module thermal storage device 20 to the set value; adjust the frequency of the molten salt pump 19 and the opening of the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, and the twenty-second steam-water valve 6-22 to bring the cold-side outlet temperature of the module thermal storage device 20 to the set value; adjust the opening of the fifteenth steam-water valve 6-15 and the sixteenth steam-water valve 6-16 to bring the cold-side flow rate into the energy release heat exchanger 30 to the set value; adjust the frequency of the high-temperature pump 29 to bring the cold-side outlet temperature of the energy release heat exchanger 30 to the set value. During the later stages of energy release, as the cold-side outlet temperature of the module thermal storage device 20 decreases, the eighteenth steam-water valve 6-18 is closed, the nineteenth steam-water valve 6-19 is opened, and the frequency of the molten salt pump 19, the opening of the twentieth steam-water valve 6-20, the twenty-first steam-water valve 6-21, and the twenty-second steam-water valve 6-22 are readjusted to bring the cold-side outlet temperature of the module thermal storage device 20 to a new set value.

[0087] The control logic for starting up a boiler in a multi-heat-source modular composite thermal storage system for a thermal power generation system is as follows; Start water pump 16, molten salt pump 19 and high temperature pump 29. Open the fourteenth steam-water valve 6-14, the twenty-eighth steam-water valve 6-28, the twenty-fifth steam-water valve 6-25, the twenty-third steam-water valve 6-23, the twentieth steam-water valve 6-20, the twenty-second steam-water valve 6-22, the seventeenth steam-water valve 6-17, the first steam-water valve 6-1, the second steam-water valve 6-2, and the third steam-water valve 6-3. Close the fourth steam-water valve 6-4, the thirteenth steam-water valve 6-13, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, the nineteenth steam-water valve 6-19, the twenty-first steam-water valve 6-21, the twenty-fourth steam-water valve 6-24, the twenty-sixth steam-water valve 6-26, and the twenty-seventh steam-water valve 6-27. Control the steam-water valves of the remaining thermal power generation system according to the conventional start-up procedure. Adjust the frequency of the start-up water pump 16 to make the steam flow rate entering the auxiliary steam header 8 reach the set value; adjust the frequency of the molten salt pump 19, the frequency of the high temperature pump 29, and the opening of the 20th steam-water valve 6-20 and the 22nd steam-water valve 6-22 to make the cold side outlet temperature of the module heat storage device 20 reach the set value. When the thermal power generation system is started, the feedwater from the deaerator 11 passes through the start-up water pump 16, the cold side of the energy release heat exchanger 30, the heat exchange pipe 23 of the module heat storage device 20, and the first steam-water separator 7 in sequence. The steam separated by the first steam-water separator 7 enters the auxiliary steam header 8 to supply the steam required for the start-up of the power generation system, and the separated condensate returns to the deaerator 11.

[0088] In addition to energy storage operation and energy release operation, the multi-heat source modular composite thermal storage system has three scenarios: short-term hot standby, short-term shutdown hot standby, and long-term shutdown cold standby. The control logic for the three scenarios is as follows. Short-term hot standby: When the time interval between the end of thermal storage operation and the start of energy release operation or the end of energy release operation and the start of energy storage operation is ≤48h, it is considered short-term hot standby. During the short-term hot standby period, no additional measures need to be taken for the multi-heat source modular composite thermal storage system. Short-term shutdown hot standby: When the time interval between the end of thermal storage operation and the start of energy release operation or the end of energy release operation and the start of energy storage operation is 48-480 hours, it is considered short-term shutdown hot standby. During the short-term shutdown hot standby period, 1-20 tons / day of hot steam must be introduced into the multi-heat source modular composite thermal storage system to maintain the hot standby status. When steam is supplied, molten salt pump 19 and cryogenic pump 26 operate at low power. The fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 are open. The first steam-water valve 6-1, the second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, and the nineteenth steam-water valve 6-1... 9. The twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the twenty-third steam-water valve 6-23, the twenty-fifth steam-water valve 6-25, the twenty-sixth steam-water valve 6-26, and the twenty-eighth steam-water valve 6-28 are closed, while the remaining steam-water valves of the thermal power generation system remain open. When the heat storage medium in the cryogenic storage tank 27 is insufficient or the temperature is too low, the high-temperature pump 29 is activated to supplement it. Specifically, the external hot steam can come from the reheat steam of the thermal power generation system or steam from other sources added through the steam-water pipeline.

[0089] Long-term shutdown for cold standby: A period of >480 hours between the end of thermal storage operation and the start of energy release operation, or between the end of energy release operation and the start of energy storage operation, constitutes long-term shutdown for cold standby. During this period, no additional measures are required for the multi-source modular composite thermal storage system; the system gradually and naturally cools down and the molten salt solidifies. When restarting is required after the cold standby period, steam at a flow rate not exceeding 30% of the rated flow is introduced. Low-temperature pump 26 and high-temperature pump 26 are started, and the fourth steam-water valve 6-4, the seventeenth steam-water valve 6-17, the twentieth steam-water valve 6-20, the twenty-fourth steam-water valve 6-24, and the twenty-seventh steam-water valve 6-27 are opened. The first steam-water valve 6- 1. The second steam-water valve 6-2, the third steam-water valve 6-3, the thirteenth steam-water valve 6-13, the fourteenth steam-water valve 6-14, the sixteenth steam-water valve 6-16, the eighteenth steam-water valve 6-18, the nineteenth steam-water valve 6-19, the twenty-first steam-water valve 6-21, the twenty-second steam-water valve 6-22, the twenty-third steam-water valve 6-23, the twenty-fifth steam-water valve 6-25, the twenty-sixth steam-water valve 6-26, and the twenty-eighth steam-water valve are closed. The steam-water valves of the remaining thermal power generation system remain open until the temperature of the heat storage medium in the module heat storage device 20 is ≥20℃ higher than the melting point of the molten salt, at which point the system enters a short-term shutdown hot standby state.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multi-heat-source modular composite thermal energy storage system coupled with thermal power, characterized in that, This includes thermal power generation systems and multi-source modular composite thermal storage systems; The thermal power generation system includes a boiler, a steam turbine, a generator, a condenser, a cryogenic heater, a deaerator, a high-temperature heater, a first steam-water separator, and an auxiliary steam header; the multi-heat source modular composite thermal energy storage system includes an electric heater, a modular thermal energy storage device, a second steam-water separator, an energy storage heat exchanger, a cryogenic storage tank, a high-temperature storage tank, and an energy release heat exchanger, wherein the modular thermal energy storage device includes a modular thermal energy storage medium and heat exchange pipes arranged in the modular thermal energy storage medium; The steam outlet of the boiler is connected to the steam turbine and drives the generator to generate electricity. The outlet of the steam turbine is connected in sequence to the condenser, the water side of the low-temperature heater, the deaerator, the water side of the high-temperature heater, and the feedwater inlet of the boiler. The steam-side inlets of the high-temperature heater and the low-temperature heater, as well as the deaerator, are all connected to the turbine outlet. The steam-side condensate outlet of the high-temperature heater is connected to the deaerator, and the steam-side condensate outlet of the low-temperature heater is connected to the condenser. The steam outlet of the first steam-water separator is connected to the auxiliary steam header, and the condensate outlet is connected to the deaerator. The electric heater is connected to the generator. The bottom molten salt outlet of the module heat storage device is connected to the electric heater, and the molten salt outlet of the electric heater is connected to the top of the module heat storage device. The heat exchange pipe of the module heat storage device is connected to the water side of the high temperature heater and the inlet of the first steam-water separator, and is connected to the inlet of the second steam-water separator and the steam outlet of the boiler. The outlet of the second steam-water separator is connected in sequence to the hot side of the energy storage heat exchanger and the water side of the low temperature heater. The cold side of the energy release heat exchanger is connected to the water side of the low-temperature heater, and the outlet of the low-temperature storage tank is sequentially connected to the cold side of the energy storage heat exchanger, the high-temperature storage tank, the hot side of the energy release heat exchanger, and the inlet of the low-temperature storage tank.

2. The multi-heat-source modular composite thermal energy storage system coupled with thermal power as described in claim 1, characterized in that, The modular thermal storage device includes multiple parallel modular thermal storage units, with at least two parallel units. Each modular thermal storage unit connects multiple thermal storage modules in series with molten salt through an overflow pipe, with at least two modules connected in series. Furthermore, each modular thermal storage unit connects multiple thermal storage modules in series with heat exchange pipes through an external steam-water pipe. The modular thermal storage device supports both electric heating and steam heating methods and can operate independently or in combination.

3. The multi-heat-source modular composite thermal energy storage system coupled with thermal power as described in claim 1 or 2, characterized in that, The modular thermal storage device is provided with at least three thermal storage modules. The inlet of the bottom thermal storage module of the modular thermal storage device is directly connected to the steam and water pipe connected to the outlet of the top thermal storage module through the twenty-second steam and water valve. The middle heat storage module of the modular heat storage device is directly connected to the steam and water pipe connected to the outlet of the top heat storage module through the twenty-first steam and water valve, and the number of middle modules is at least one.

4. The multi-heat-source modular composite thermal energy storage system coupled with thermal power as described in claim 3, characterized in that, The high-temperature heater includes at least a third high-temperature heater, a second high-temperature heater, and a first high-temperature heater connected in series; The heat exchange pipes of the modular thermal storage device are connected to the water-side inlet or outlet of multiple high-temperature heaters in the thermal power generation system. The heat exchange pipes of the top thermal storage module are connected to the water side of the high-temperature heaters through at least two steam-water valves, and the heat exchange pipes of the bottom thermal storage module are connected to the water side of the high-temperature heaters through at least one steam-water valve.

5. The multi-heat-source modular composite thermal energy storage system coupled with thermal power according to claim 4, characterized in that, The cryogenic heater includes at least a third cryogenic heater, a second cryogenic heater, and a first cryogenic heater connected in series; The connection position between the hot side outlet of the energy storage heat exchanger and the water side of the low-temperature heater is determined based on the temperature matching principle, and the absolute value of the temperature difference between the hot side outlet temperature of the energy storage heat exchanger and the temperature at the connection position of the water side of the low-temperature heater is controlled to not exceed 20℃.

6. The multi-heat-source modular composite thermal energy storage system coupled with thermal power as described in claim 5, characterized in that, The steam turbine includes a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder connected in series. The boiler has a feedwater inlet, a main steam outlet, a reheat steam inlet, and a reheat steam outlet. The main steam outlet of the boiler is connected to the inlet of the high-pressure cylinder, and the outlet of the high-pressure cylinder is connected to the reheat steam inlet of the boiler. The reheat steam outlet of the boiler is connected in sequence to the intermediate-pressure cylinder and the low-pressure cylinder and drives the generator to generate electricity.

7. The multi-heat-source modular composite thermal energy storage system coupled with thermal power as described in claim 6, characterized in that, The outlet of the high-pressure cylinder is connected to the second high-temperature heater and the first high-temperature heater through two steam-water valves, respectively. The outlet of the medium-pressure cylinder is connected to the third high-temperature heater, the deaerator and the first low-temperature heater through three steam-water valves, respectively. The outlet of the low-pressure cylinder is connected to the remaining low-temperature heaters through multiple steam-water valves, respectively.

8. The multi-heat-source modular composite thermal energy storage system coupled with thermal power according to claim 7, characterized in that, A condensate pump and a shaft seal heater are sequentially provided between the condenser and the low-temperature heater; a feed water pump is provided between the deaerator and the high-temperature heater; and a start-up water pump is provided between the deaerator and the energy release heat exchanger. A molten salt pump is provided between the molten salt outlet at the bottom of the module thermal storage device and the electric heater. A low-temperature pump and a high-temperature pump are respectively provided between the outlet of the low-temperature storage tank and the energy storage heat exchanger, and between the high-temperature storage tank and the energy release heat exchanger.

9. The multi-heat-source modular composite thermal energy storage system coupled with thermal power as described in claim 8, characterized in that, A transformer is installed between the electric heater and the generator.

10. The multi-heat-source modular composite thermal energy storage system coupled with thermal power according to claim 8, characterized in that, The multi-heat source modular composite thermal storage system is configured as the start-up boiler of a thermal power generation system. The heat exchange pipe of the modular thermal storage device is connected to the inlet of the first steam-water separator and to the cold side outlet of the energy release heat exchanger. The cold side inlet of the energy release heat exchanger is connected in sequence to the start-up water pump and the deaerator outlet.

11. The multi-heat-source modular composite thermal energy storage system coupled with thermal power as described in claim 8, characterized in that, The heat storage medium of the modular heat storage device is molten salt or a combination of molten salt and solid heat storage medium; the heat storage medium in the low-temperature storage tank and the high-temperature storage tank is water, heat transfer oil or a combination of liquid and solid heat storage medium.

12. The multi-heat-source modular composite thermal energy storage system coupled with thermal power according to claim 8, characterized in that, The heat exchange pipes of the modular heat storage device are connected to the reheat steam outlet of the boiler, supporting the cascade utilization of steam energy, realizing the storage of high-temperature sensible heat and medium-temperature latent heat, and reducing the amount of steam extracted.

13. A control method for a multi-heat-source modular composite thermal energy storage system coupled with thermal power, applicable to the system described in any one of claims 8-12, characterized in that, Includes the energy storage stage and the energy release stage; The energy storage phase includes electric energy storage mode, steam energy storage mode, and electric-steam hybrid energy storage mode; In electric energy storage mode, the molten salt pump is started, and the generator supplies power to the electric heater to heat the molten salt. The frequency of the molten salt pump and the power of the electric heater are adjusted according to the preset molten salt outlet temperature. The molten salt flows from the bottom of the module thermal storage device through the molten salt pump and the electric heater to the top, and then flows down through the overflow pipe to achieve energy storage. In steam energy storage mode, the molten salt pump and the cryogenic pump are started; the flow rate of the steam-water pipeline on the hot side of the energy storage heat exchanger, the frequency of the molten salt pump and the cryogenic pump are adjusted so that the outlet temperature and flow rate of the module heat storage device and the energy storage heat exchanger on the hot side reach the set values; after the steam from the thermal power generation system enters the module heat storage device, the steam and condensate are separated by the second steam-water separator and enter the heat side of the energy storage heat exchanger to heat the medium in the cryogenic storage tank, and the condensate is returned to the water side of the cryogenic heater; In the electric-steam hybrid energy storage mode, the molten salt pump, cryogenic pump, and electric heater are started simultaneously; the power of the electric heater, the flow rate of the steam-water pipeline where the heat side of the energy storage heat exchanger is located, and the frequency of the molten salt pump and cryogenic pump are adjusted so that the outlet temperature and flow rate of the module heat storage device and the heat side of the energy storage heat exchanger reach the set values, and the molten salt outlet temperature of the electric heater is constrained to avoid overheating.

14. The control method according to claim 13, characterized in that, The energy release phase includes a feedwater mode for heating a high-temperature heater, a feedwater mode for heating a low-temperature heater, and a feedwater mode for heating both high- and low-temperature heaters. In the high-temperature heater feedwater mode, the molten salt pump is started. In the early stage of energy release, the cold side outlet of the module thermal storage device is directly connected to the water side inlet of the boiler or high-temperature heater. The flow rate of the steam-water pipeline and the frequency of the molten salt pump connected to the water side of the high-temperature heater are adjusted so that the cold side flow rate and outlet temperature of the module thermal storage device reach the set values. In the later stage of energy release, the cold side outlet temperature of the module thermal storage device decreases. The water side inlet of the high-temperature heater connected to the cold side outlet of the module thermal storage device is controlled, and the flow rate of the steam-water pipeline and the frequency of the molten salt pump connected to the water side of the high-temperature heater are readjusted so that the cold side flow rate and outlet temperature of the module thermal storage device reach the new set values. In the low-temperature heater feedwater mode, start the high-temperature pump, open the steam-water pipeline where the cold side of the energy release heat exchanger is located and adjust its flow rate, adjust the frequency of the high-temperature pump, so that the flow rate and outlet temperature of the cold side of the energy release heat exchanger reach the set values. In the heating mode of the high and low temperature heater feedwater, the molten salt pump and the high temperature pump are started simultaneously. In the early stage of energy release, the cold side outlet of the module thermal storage device is directly connected to the water side inlet of the boiler or the high temperature heater. The steam-water pipeline where the cold side of the energy release heat exchanger is located is opened and its flow rate is adjusted. The flow rate of the steam-water pipeline, the frequency of the molten salt pump and the frequency of the high temperature pump, which are connected to the water side of the high temperature heater by the cold side inlet of the module thermal storage device are adjusted respectively, so that the cold side flow rate and outlet temperature of the module thermal storage device and the energy release heat exchanger reach the set values. In the later stage of energy release, the cold-side outlet temperature of the modular thermal storage device decreases. The water-side inlet of the high-temperature heater connected to the cold-side outlet of the modular thermal storage device is controlled, and the flow rate of the steam-water pipeline and the frequency of the molten salt pump connected to the water side of the high-temperature heater are readjusted so that the cold-side flow rate and outlet temperature of the modular thermal storage device reach the new set values.

15. The control method according to claim 13, characterized in that, It also includes a boiler start-up mode, which involves turning on the start-up water pump, molten salt pump and high-temperature pump, opening the steam-water valves for the feedwater to the cold side of the energy release heat exchanger, the cold side of the module heat storage device and the first steam-water separator and adjusting their opening degree. Adjust the frequency of the start-up water pump to make the steam flow of the auxiliary steam header reach the set value, and adjust the frequency of the molten salt pump and the high-temperature pump to make the cold side outlet temperature of the module heat storage device reach the set value; the feedwater of the deaerator passes through the cold side of the energy release heat exchanger, the heat exchange pipeline of the module heat storage device and the first steam-water separator, and the separated steam is supplied to the auxiliary steam header, while the condensate is returned to the deaerator.

16. The control method according to claim 13, characterized in that, It also includes backup modes, including short-term hot backup, short-term shutdown hot backup, and long-term shutdown cold backup; Short-term hot standby is suitable for energy storage / release intervals not exceeding 48 hours, requiring no additional measures; Short-term shutdown hot standby is applicable at intervals of 48-480 hours. It requires the supply of 1-20 tons / day of hot steam to maintain operation, and the operation of molten salt pumps and cryogenic pumps. The steam-water valves for the module thermal storage device and energy storage heat exchanger should be opened. If the medium in the cryogenic storage tank is insufficient or the temperature is low, the high-temperature pump should be turned on to supplement it. Long-term shutdown cold standby is suitable for intervals exceeding 480 hours, without any measures, allowing the system to cool down naturally and the molten salt to solidify; when restarting, steam not exceeding 30% of the rated flow rate is introduced, the cryogenic pump and the high-temperature pump are started, and the steam-water valves for the module thermal storage device and the energy storage heat exchanger are opened until the temperature of the thermal storage medium in the module thermal storage device is at least 20°C higher than the melting point of the molten salt, after which it is switched to short-term shutdown hot standby.

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