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CN-122015548-A - Multi-heat source module type composite heat storage system coupled with thermal power and control method thereof

CN122015548ACN 122015548 ACN122015548 ACN 122015548ACN-122015548-A

Abstract

The invention belongs to the technical field of thermal power generation and energy storage, and relates to a multi-heat source module type composite heat storage system for coupling thermal power and a control method thereof, wherein the multi-heat source module type composite heat storage system comprises a thermal power generation system and a multi-heat source module type composite heat storage system; the multi-heat source module type composite heat storage system comprises an electric heater, a module 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. According to the invention, the cascade utilization of steam energy is realized by utilizing the coupling of the modular molten salt heat storage device and the heat conduction oil/pressurized water heat storage device, the high-temperature sensible heat and medium Wen Qianre of steam are completely stored, the steam extraction quantity is greatly reduced, the rapid deep peak regulation of the thermal power unit is realized by matching with the electric heating source of the modular molten salt heat storage device, and meanwhile, the boiler starting function is realized, and the flexibility and the economical efficiency of thermal power are effectively improved.

Inventors

  • ZHU MENG
  • WANG FANGMING
  • ZHOU TAO
  • WANG YI

Assignees

  • 重庆赛迪热工环保工程技术有限公司

Dates

Publication Date
20260512
Application Date
20260129

Claims (16)

  1. 1. The multi-heat source module type composite heat storage system for coupling thermal power is characterized by comprising a thermal power generation system and a multi-heat source module type composite heat storage system; The multi-heat source module type composite heat storage system comprises an electric heater, a module 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, wherein the module heat storage device comprises a module heat storage medium and a heat exchange pipeline arranged in the module heat storage medium; the steam outlet of the boiler is communicated with a steam turbine and drives the generator to generate power, and the outlet of the steam turbine is sequentially communicated with a condenser, a low-temperature heater water side, a deaerator, a high-temperature heater water side and a water supply inlet of the boiler; The steam side inlets of the high-temperature heater and the low-temperature heater and the deaerator are communicated with the outlet of the steam turbine, the steam side drain outlet of the high-temperature heater is communicated with the deaerator, the steam side drain outlet of the low-temperature heater is communicated with the condenser, the steam outlet of the first steam-water separator is communicated with the auxiliary steam header, and the drain outlet is communicated with the deaerator; The electric heater is connected with the generator, a molten salt outlet at the bottom of the module heat storage device is communicated with the electric heater, the molten salt outlet of the electric heater is communicated with the top of the module heat storage device, a heat exchange pipeline of the module heat storage device is communicated with the water side of the high-temperature heater and the inlet of the first steam-water separator, and is communicated with the inlet of the second steam-water separator and the steam outlet of the boiler, and the outlet of the second steam-water separator is sequentially communicated with the hot side of the energy storage heat exchanger and the water side of the low-temperature heater; the energy release heat exchanger cold side is communicated with the low-temperature heater water side, and the outlet of the low-temperature storage tank is sequentially communicated with the energy storage heat exchanger cold side, the high-temperature storage tank, the energy release heat exchanger hot side and the low-temperature storage tank inlet.
  2. 2. The multi-heat source module type composite heat storage system for coupling thermal power according to claim 1, wherein the module heat storage device comprises a plurality of module heat storage units which are connected in parallel, the number of the module heat storage units is at least 2, each module heat storage unit is used for connecting molten salt in the plurality of heat storage modules in series through overflow pipelines, the number of the module heat storage units is at least 2, each module heat storage unit is used for connecting heat exchange pipelines in the plurality of heat storage modules in series through external steam-water pipelines, and the module heat storage device supports two modes of electric heating and steam heating and can independently or jointly operate.
  3. 3. The multi-heat source module type composite heat storage system for coupling thermal power according to claim 1 or 2, wherein at least three heat storage modules are arranged in the module heat storage device, and a bottom heat storage module inlet of the module heat storage device is directly communicated with a steam-water pipeline connected with a top heat storage module outlet through a twenty-second steam-water valve; the middle heat storage module of the module heat storage device is directly communicated with a steam-water pipeline connected with the outlet of the top heat storage module through a twenty-first steam-water valve, and the number of the middle modules is at least 1.
  4. 4. The multi-heat source modular composite thermal storage system of claim 3, wherein the high temperature heater comprises at least a third high temperature heater, a second high temperature heater, and a first high temperature heater in series; The heat exchange pipelines of the module heat storage device are communicated with inlets or outlets of water sides of a plurality of high-temperature heaters in the thermal power generation system, wherein the number of the heat exchange pipelines of the top heat storage module communicated with the water sides of the high-temperature heaters through at least 2 steam-water valves is at least 2, and the number of the heat exchange pipelines of the bottom heat storage module communicated with the water sides of the high-temperature heaters through at least 1 steam-water valve is at least 1.
  5. 5. The multiple heat source module type composite heat storage system coupled with thermal power according to claim 4, wherein the low temperature heater at least comprises a third low temperature heater, a second low temperature heater and a first low temperature heater connected in series; And the communication 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 a 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 of the water side connection position of the low-temperature heater is controlled to be not more than 20 ℃.
  6. 6. The multiple heat source modular composite thermal storage system of claim 5, wherein the steam turbine comprises a high pressure cylinder, a medium pressure cylinder and a low pressure cylinder connected in series, the boiler has a water feed inlet, a main steam outlet, a reheat steam inlet and a reheat steam outlet, the main steam outlet of the boiler is communicated with the high pressure cylinder inlet, the high pressure cylinder outlet is communicated with the reheat steam inlet of the boiler, and the reheat steam outlet of the boiler is sequentially communicated with the medium pressure cylinder, the low pressure cylinder and drives a generator to generate electricity.
  7. 7. The multi-heat source modular composite heat storage system for coupling thermal power according to claim 6, wherein the outlet of the high pressure cylinder is respectively connected with the second high temperature heater and the first high temperature heater through two steam-water valves, the outlet of the medium pressure cylinder is respectively connected with the third high temperature heater, the deaerator and the first low temperature heater through three steam-water valves, and the outlet of the low pressure cylinder is respectively connected with the rest of the low temperature heaters through a plurality of steam-water valves.
  8. 8. The multi-heat source module type composite heat storage system for coupling thermal power according to claim 7, wherein a condensate pump and a shaft seal heater are sequentially arranged between the condenser and the low-temperature heater, a water supply pump is arranged between the deaerator and the high-temperature heater, and a starting water pump is arranged between the deaerator and the energy release heat exchanger; and a molten salt pump is arranged between the molten salt outlet at the bottom of the module heat storage device and the electric heater, and a low-temperature pump and a high-temperature pump are respectively arranged between the low-temperature storage tank outlet and the energy storage heat exchanger and between the high-temperature storage tank and the energy release heat exchanger.
  9. 9. The multiple heat source modular composite thermal storage system of claim 8, wherein a transformer is provided between the electric heater and the generator.
  10. 10. The multiple heat source modular composite thermal storage system coupled to thermal power of claim 8, wherein the multiple heat source modular composite thermal storage system is configured as a start-up boiler of a thermal power generation system, wherein the heat exchange conduit of the modular thermal storage device is in communication with the first steam-water separator inlet and with the energy release heat exchanger cold side outlet, and the energy release heat exchanger cold side inlet is in turn connected to the start-up water pump and the deaerator outlet.
  11. 11. The multi-heat source module type composite heat storage system for coupling thermal power according to claim 8, wherein the heat storage medium of the module heat storage device is molten salt or composite of molten salt and solid heat storage medium, and the heat storage medium in the low-temperature storage tank and the high-temperature storage tank is water, heat conduction oil or composite of liquid and solid heat storage medium.
  12. 12. The multi-heat source module type composite heat storage system for coupling thermal power according to claim 8, wherein a heat exchange pipeline of the module heat storage device is communicated with a reheat steam outlet of a boiler, supports the cascade utilization of steam energy, realizes the storage of high-temperature sensible heat and medium Wen Qianre, and reduces the steam extraction quantity.
  13. 13. A control method of a multi-heat source modular composite heat storage system for coupling thermal power, which is applicable to the system of any one of claims 8-12, and is characterized by comprising an energy storage stage and an energy release stage; The energy storage stage comprises an electric energy storage mode, a steam energy storage mode and an electric-steam hybrid energy storage mode; In an electric energy storage mode, starting a molten salt pump, supplying power to the electric heater by using a generator to heat molten salt, and regulating the frequency of the molten salt pump and the power of the electric heater according to the preset molten salt outlet temperature; The method comprises the steps of starting a molten salt pump and a low-temperature pump in a steam energy storage mode, adjusting the flow of a steam-water pipeline where the hot side of an energy storage heat exchanger is located, and the frequencies of the molten salt pump and the low-temperature pump to enable the outlet temperatures and the flow of the hot sides of a module heat storage device and the energy storage heat exchanger to reach set values; And adjusting the power of the electric heater, the flow of a steam-water pipeline where the hot side of the energy storage heat exchanger is positioned, and the frequencies of the molten salt pump and the low-temperature pump, so that the outlet temperature and the flow of the hot side of the module heat storage device and the energy storage heat exchanger reach set values, and restricting the outlet temperature of the molten salt of the electric heater to avoid over-temperature.
  14. 14. The control method of claim 13, wherein the energy release phase comprises a heating high temperature heater feed water mode, a heating low temperature heater feed water mode, and a heating high and low temperature heater feed water mode; Starting a molten salt pump in a water supply mode of a heating high-temperature heater, wherein a cold side outlet of the module heat storage device is directly connected with a boiler or a water side inlet of the high-temperature heater in the early stage of energy release, and adjusting the flow rate of a steam-water pipeline and the frequency of the molten salt pump, which are connected with the water side of the high-temperature heater, of the cold side inlet of the module heat storage device so that the flow rate and the outlet temperature of the cold side of the module heat storage device reach set values; In the later period of energy release, the temperature of the cold side outlet of the module heat storage device is reduced, the cold side outlet of the module heat storage device is controlled to be connected with the water side inlet of the subsequent-stage high-temperature heater, and the flow rate and the frequency of a steam-water pipeline connected with the water side of the high-temperature heater through the cold side inlet of the module heat storage device are readjusted, so that the flow rate and the outlet temperature of the cold side of the module heat storage device reach new set values; Starting a high-temperature pump in a water supply mode of a heating low-temperature heater, starting a steam-water pipeline where the cold side of the energy release heat exchanger is positioned, adjusting the flow of the steam-water pipeline, and adjusting the frequency of the high-temperature pump to enable the flow of the cold side of the energy release heat exchanger and the temperature of an outlet of the energy release heat exchanger to reach set values; In the water supply mode of the heating high-low temperature heater, a molten salt pump and a high-temperature pump are started at the same time, the cold side outlet of the module heat storage device is directly connected with the water side inlet of the boiler or the high-temperature heater in the early energy release period, a steam-water pipeline where the cold side of the energy release heat exchanger is positioned is opened, and the flow of the steam-water pipeline is regulated; and in the later energy release period, the temperature of the cold side outlet of the module heat storage device is reduced, the cold side outlet of the module heat storage device is controlled to be connected with the water side inlet of the rear-stage high-temperature heater, the steam-water pipeline flow and the frequency of the water side of the high-temperature heater are readjusted, and the cold side flow and the outlet temperature of the module heat storage device reach new set values.
  15. 15. The control method of claim 13, further comprising activating a boiler mode, activating the activation water pump, molten salt pump, and high temperature pump, activating steam-water valves for feed water into the cold side of the energy-releasing heat exchanger, the cold side of the module heat storage device, and the first steam-water separator, and adjusting the opening thereof; The water supply of the deaerator is separated from the steam to supply the auxiliary steam header 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 condensed water returns to the deaerator.
  16. 16. The control method of claim 13, further comprising a standby mode comprising a short-term hot standby, a short-term shutdown hot standby, and a long-term shutdown cold standby; Short-term hot standby is suitable for energy storage/release intervals of not more than 48 hours, and no extra measures are needed; Short-term shutdown hot standby is suitable for maintaining at intervals of 48-480 hours by introducing 1-20 tons/day of hot steam, operating a molten salt pump and a low-temperature pump, and starting steam valves of a steam-inlet module heat storage device and an energy storage heat exchanger; the long-term shutdown cold standby is suitable for cooling down and solidifying molten salt naturally without measures at intervals of more than 480 hours, and when restarting, steam with the flow rate not exceeding 30% of rated flow is fed, a low-temperature pump and a high-temperature pump are started, steam is fed into steam-water valves of a module heat storage device and an energy storage heat exchanger, and short-term shutdown hot standby is carried out after the temperature of a heat storage medium in the module heat storage device is at least 20 ℃ higher than the melting point of the molten salt.

Description

Multi-heat source module type composite heat storage system coupled with thermal power and control method thereof Technical Field The invention belongs to the technical field of thermal power generation and energy storage, and relates to a multi-heat source module type composite heat storage system for coupling thermal power and a control method thereof. Background The thermal power generation is gradually changed from basic energy into regulation energy under the influence of the great increase and fluctuation of new energy. However, the peak regulation capability of the thermal power generating unit, especially the old unit, is poor, the minimum operation output is usually more than 30% Pe, the lifting load rate is usually 2% -2.5% Pe/min, the power supply coal consumption of the thermal power generating unit is greatly increased during low load output, and the peak regulation requirement of the power grid which is gradually increased is difficult to meet. In addition, before the boiler ignites, the thermal power generating unit can not generate steam, and partial equipment needs to supply a steam heating pipe in advance, so that support is provided for normal ignition. At present, a small-sized fuel oil or coal-fired boiler is mainly used as a starting boiler, and the defects of low starting speed, high risk, high fuel cost and the like exist. The fused salt heat storage technology is a feasible scheme for solving the problems, for example, a steam and electricity heat storage coupling heat storage system and method with the patent application number of CN202510236657.6 are used for storing redundant electric energy and heat energy of a thermal power unit by fused salt, so that the online power of thermal power at a valley section is reduced, and meanwhile, the heat energy is quickly released back to a generator unit when the power demand is high, and quick peak power generation is realized. On the other hand, the heat energy stored by the energy storage system can be used for supplying steam required by starting the thermal power generating unit to replace the original starting boiler of the unit, so that two purposes are achieved. However, the conventional double-tank molten salt system has the obvious defects that 1, a pipeline electric tracing system is required to be maintained in the whole operation stage to prevent additional energy consumption caused by solidification of molten salt in the conveying process, 2, continuous electric heating is required to maintain the molten salt in a liquid state during the shutdown period of a storage tank, the operation and maintenance cost is high, 3, the double-tank heat storage system is large in size and high in investment, 4, the system reliability is limited by the construction quality of a large storage tank, and the whole system can be stopped due to single-point failure. In addition, the electric heating molten salt can realize zero output of the generator, but the energy storage conversion efficiency is only 30% -40%, the conversion efficiency of the steam heating molten salt can exceed 70%, but the melting point of the binary molten salt and the ternary molten salt which are mature in the prior art is higher, the latent heat during steam heating is difficult to fully utilize, the extraction amount is too large if only the sensible heat is utilized, the safety and the economy are insufficient, and a thermal power unit is difficult to supply a large amount of extraction steam during low-load operation. Disclosure of Invention In view of the above, the present invention is directed to a multi-heat source module type composite heat storage system coupled with thermal power and a control method thereof, so as to solve the problems set forth in the background art. In order to achieve the above purpose, the present invention provides the following technical solutions: A multi-heat source module type composite heat storage system for coupling thermal power comprises a thermal power generation system and a multi-heat source module type composite heat storage system; The multi-heat source module type composite heat storage system comprises an electric heater, a module 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, wherein the module heat storage device comprises a module heat storage medium and a heat exchange pipeline arranged in the module heat storage medium; the steam outlet of the boiler is communicated with a steam turbine and drives the generator to generate power, and the outlet of the steam turbine is sequentially communicated with a condenser, a low-temperature heater water side, a deaerator, a high-temperature heater water side and a water supply inlet of the boiler; The steam side inlets of the high-temperature heater and the low-temperature heater and the deaerator are communicated with the outlet of the stea