Power generation peak regulation system with heat supply unit coupled with fused salt heat storage and operation method

Abstract

The invention discloses a heat supply unit coupling fused salt heat storage power generation peak regulation system and an operation method.The system comprises a power station boiler, a turboset and a fused salt heat storage peak regulation device, and the fused salt heat storage peak regulation device comprises a low-temperature fused salt storage tank, a high-temperature fused salt storage tank, a fused salt heat storage mechanism and a fused salt heat release mechanism; the fused salt heat storage mechanism heats fused salt in a stepped mode through steam waste heat, flue gas waste heat and electric energy for heat storage, heat obtained after the waste heat is recycled is used for heat supply through steam, and when the system is subjected to load rising and peak shaving, the fused salt heat release mechanism conducts three-stage cooling heat exchange on the high-temperature fused salt for heat release. High-parameter steam generated by high-temperature molten salt cascade heat release is returned to the turboset to do work and generate power, and medium-parameter steam is generated to replace steam extraction and heat supply of the turboset to increase power generation of the turboset. By reasonably designing a multi-stage heat exchange flow process in the fused salt heat storage and release process, cascade efficient utilization of different grades of energy is achieved, and the high efficiency and flexibility of system operation are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal power flexibility, and specifically relates to a power generation peak-shaving system and an operation method of a heating unit coupled with molten salt heat storage, and is particularly suitable for a cogeneration unit for power peak-shaving. Background Art

[0002] At present, the proportion of flexible regulating power sources in the power grid is low, resulting in a high proportion of new energy power connected to the power grid, leading to serious "wind and solar abandonment" phenomenon. Therefore, it is urgent to increase the proportion of flexible regulating power sources in the power grid to enhance the power grid's ability to absorb new energy power. At this stage, thermal power generation is still the basic power source to ensure social electricity consumption, and will also be an important stable power source for participating in power grid peak regulation. Further improving the flexibility and efficiency of thermal power units, especially cogeneration units, and promoting the transformation of thermal power from the main body of electricity to the main body of capacity can solve the problem of insufficient flexible regulating power sources in the power grid, which is crucial to promoting the absorption of new energy and accelerating the construction of a new power system.

[0003] When choosing the technical route for the flexibility transformation of thermal power units, we must consider the requirements of different current application scenarios and also meet the needs of power plants to gradually replace traditional fossil energy in the future and help achieve carbon neutrality goals. For industrial heating units, the heat storage technology used for the flexibility transformation of thermal power must be a heat storage technology that can output high-parameter steam. Molten salt heat storage technology not only meets this requirement, but also relies on its advantages of long cycle, large capacity, and low cost to adjust the fluctuations of new energy power generation over a longer time dimension, truly realizing the "peak shaving and valley filling" of the power grid.

[0004] At present, the relevant technologies for thermal power units to use molten salt heat storage for power peak regulation mainly include: (1) A deep peak regulation system and method of high-temperature flue gas coupled with reheated steam heat storage in power station boilers (patent application number 202010917835.9). The disadvantage is that during heat storage, high-temperature flue gas and high-parameter steam are directly used to directly heat the low-temperature molten salt energy storage, and during heat release, high-temperature molten salt is directly used to produce high-temperature hot water for heating. The heat exchange temperature difference in the heat storage and heat release processes is too large, resulting in serious loss of work capacity; (2) A power generation peak regulation system and method for thermal power units based on steam full heat heating molten salt heat storage (patent application number 201910410021.3). The disadvantage is that during heat storage, reheated steam is used to heat the low-temperature molten salt energy storage to achieve low-load operation of the unit, and during heat release, High-temperature molten salt is used to release energy to heat the feed water to generate steam for power generation to achieve high-load operation of the unit. It is mainly used in the peak-shaving scenario of thermal power pure condensing units. In the process of molten salt heat release, the heat exchange temperature difference is large, and the resulting work capacity loss is relatively large; (3) A system based on electric heating and heat storage technology to greatly improve the reliability of industrial steam supply (patent application number 202110686591.2). Its disadvantage is that during heat storage, high-grade electricity is used to directly heat low-temperature molten salt energy storage to achieve unit load reduction and peak-shaving. The high-grade electricity loss in the heat storage process is large. During heat release, high-temperature molten salt is used to directly heat the feed water to generate low-grade industrial steam to replace the unit extraction steam for load increase and peak-shaving. The heat exchange temperature difference in the heat release process is too large, resulting in serious irreversible losses, thereby resulting in low overall energy utilization efficiency in the heat storage and release process of the heat storage system. Summary of the invention

[0005] Based on the above situation, the present invention overcomes the above-mentioned shortcomings in the prior art, and proposes a power generation peak-shaving system and operation method of a heating unit coupled with molten salt heat storage with reasonable design and reliable performance. By reasonably designing the multi-stage heat exchange process of molten salt storage and heat release process, the cascade and efficient utilization of energy of different grades is achieved, thereby improving the operating efficiency of cogeneration coupled with molten salt heat storage peak-shaving.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a power generation peak-shaving system of a heating unit coupled with molten salt heat storage, comprising: a power station boiler and a steam turbine unit, wherein a superheater, a reheater and an economizer are arranged in sequence along the direction of flue gas flow in the power station boiler, and the steam turbine unit comprises a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, a generator, a condenser, a condensate pump, a low-pressure reheater, a deaerator, a boiler feed water pump, a medium-pressure reheater and a high-pressure reheater, the steam inlet of the high-pressure cylinder is connected to the steam outlet of the superheater, the steam exhaust port of the high-pressure cylinder is connected to the steam inlet of the reheater, the steam outlet of the reheater is connected to the steam inlet of the medium-pressure cylinder through a hot re-steam pipe, and a regulating valve is installed on the hot re-steam pipe. , the exhaust port of the medium-pressure cylinder is connected to the steam inlet of the low-pressure cylinder, the exhaust port of the low-pressure cylinder is connected to the exhaust steam inlet of the condenser, the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder are coaxially connected and drive the generator to generate power, the condensate outlet of the condenser is connected to the feed water inlet of the low-pressure regenerator through the condensate pump, the feed water sides of the low-pressure regenerator, the deaerator, the boiler feed water pump, the medium-pressure regenerator and the high-pressure regenerator are connected in sequence along the water flow direction, the feed water outlet of the high-pressure regenerator is connected to the feed water inlet of the power station boiler, the high-pressure cylinder provides the required steam for the high-pressure regenerator, the medium-pressure cylinder provides the required steam for the medium-pressure regenerator and the deaerator, and the low-pressure cylinder provides the required steam for the low-pressure regenerator; It also includes: a molten salt heat storage peak-shaving device and a medium-pressure industrial steam supply mother pipe, wherein the molten salt heat storage peak-shaving device includes a low-temperature molten salt storage tank, a high-temperature molten salt storage tank, a molten salt heat storage mechanism and a molten salt heat release mechanism, and the industrial steam extraction port of the medium-pressure cylinder is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe through a low-pressure industrial steam extraction pipe; The molten salt inlet and the molten salt outlet of the molten salt heat storage mechanism are connected to the molten salt outlet of the low-temperature molten salt storage tank and the molten salt inlet of the high-temperature molten salt storage tank respectively, the steam inlet of the molten salt heat storage mechanism is connected to the steam outlet of the reheater through the hot re-steam branch pipe, the steam outlet of the molten salt heat storage mechanism is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe, the molten salt inlet and the molten salt outlet of the molten salt heat release mechanism are connected to the molten salt outlet of the high-temperature molten salt storage tank and the molten salt inlet of the low-temperature molten salt storage tank respectively, the feed water inlet of the molten salt heat release mechanism is connected with a desalted water pipe, the medium-pressure steam outlet of the molten salt heat release mechanism is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe, and the high-pressure steam outlet of the molten salt heat release mechanism is connected to the steam inlet end of the hot re-steam pipe and the steam inlet end of the medium-pressure industrial steam supply mother pipe through the first steam branch pipe and the second steam branch pipe respectively; The molten salt heat storage mechanism comprises two stages of first molten salt heat exchangers connected in series, the first stage of the first molten salt heat exchanger uses high-pressure steam and high-temperature flue gas to heat low-temperature molten salt at the same time, and the second stage of the first molten salt heat exchanger uses electric energy to heat low-temperature molten salt; The molten salt heat release mechanism comprises three stages of second molten salt heat exchangers connected in series, the first stage of the second molten salt heat exchanger uses high-temperature molten salt to preheat feed water, the second stage of the second molten salt heat exchanger uses high-temperature molten salt to produce medium-pressure steam and preheat part of the feed water for a second time, and the third stage of the second molten salt heat exchanger uses high-temperature molten salt to produce high-pressure steam; The medium in the molten salt pipeline of the molten salt heat storage mechanism flows in opposite directions to the medium in the steam pipeline, and the medium in the molten salt pipeline of the molten salt heat release mechanism flows in opposite directions to the medium in the steam pipeline and the medium in the water supply pipeline.

[0007] Preferably, the first molten salt heat exchanger comprises a low-temperature molten salt pump, a steam cooling heat exchanger, a flue gas molten salt heat exchanger and a molten salt electric heater. The first stage of the first molten salt heat exchanger utilizes the steam cooling heat exchanger and the flue gas molten salt heat exchanger to heat the low-temperature molten salt for the first time. The second stage of the first molten salt heat exchanger utilizes the molten salt electric heater to heat the low-temperature molten salt for the second time. The molten salt sides of the steam cooling heat exchanger and the flue gas molten salt heat exchanger are connected in parallel, and the molten salt sides of the steam cooling heat exchanger or the flue gas molten salt heat exchanger and the molten salt electric heater are connected in series. The low-temperature molten salt pump is arranged at the molten salt outlet of the low-temperature molten salt storage tank, and a regulating valve is installed at the molten salt outlet of the low-temperature molten salt storage tank, the molten salt outlet of the low-temperature molten salt storage tank is simultaneously connected to the molten salt inlet of the steam cooling heat exchanger and the flue gas molten salt heat exchanger, and regulating valves are installed at the molten salt inlets of the steam cooling heat exchanger and the flue gas molten salt heat exchanger, the molten salt outlets of the steam cooling heat exchanger and the flue gas molten salt heat exchanger are simultaneously connected to the molten salt inlet of the molten salt electric heater, and regulating valves are installed at the molten salt outlets of the steam cooling heat exchanger and the flue gas molten salt heat exchanger, the molten salt outlet of the molten salt electric heater is connected to the molten salt inlet of the high-temperature molten salt storage tank, and a regulating valve is installed at the molten salt inlet of the high-temperature molten salt storage tank; The steam inlet of the steam cooling heat exchanger is connected to the steam outlet of the reheater through a hot re-steam branch pipe, and regulating valves are installed on the steam inlet and the hot re-steam branch pipe of the steam cooling heat exchanger. The steam outlet of the steam cooling heat exchanger is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe. The flue gas molten salt heat exchanger is arranged between the reheater and the economizer of the power station boiler. The electric energy of the molten salt electric heater for heating the low-temperature molten salt comes from the generator.

[0008] Preferably, the second molten salt heat exchanger comprises a high-temperature molten salt pump, a high-pressure steam superheater, a high-pressure steam generator, a low-pressure steam superheater, a low-pressure steam generator, a feedwater reheater, a feedwater preheater, a No. 1 feedwater pump and a No. 2 feedwater pump. The first stage of the second molten salt heat exchanger uses the feedwater preheater to preheat the feedwater to cool the high-temperature molten salt for the third time. The second stage of the second molten salt heat exchanger uses the low-pressure steam superheater and the low-pressure steam generator to produce medium-pressure steam, and uses the feedwater reheater to preheat part of the feedwater for the second time to cool the high-temperature molten salt. The third stage of the second molten salt heat exchanger uses the high-pressure steam superheater and the high-pressure steam generator to produce high-pressure steam to cool the high-temperature molten salt for the first time. The molten salt sides of the low-pressure steam generator and the feedwater reheater are connected in parallel, and the molten salt sides of the high-pressure steam superheater, the high-pressure steam generator, the low-pressure steam superheater, the low-pressure steam generator or the feedwater reheater and the feedwater preheater are connected in series in sequence. The high-temperature molten salt pump is arranged at the molten salt outlet of the high-temperature molten salt storage tank, and a regulating valve is installed at the molten salt outlet of the high-temperature molten salt storage tank, the molten salt outlet of the high-temperature molten salt storage tank is connected to the molten salt inlet of the high-pressure steam superheater, the molten salt outlet of the high-pressure steam superheater is connected to the molten salt inlet of the high-pressure steam generator, the molten salt outlet of the high-pressure steam generator is connected to the molten salt inlet of the low-pressure steam superheater, the molten salt outlet of the low-pressure steam superheater is simultaneously connected to the molten salt inlets of the low-pressure steam generator and the feedwater reheater, and regulating valves are installed at the molten salt inlets of the low-pressure steam generator and the feedwater reheater, the molten salt outlets of the low-pressure steam generator and the feedwater reheater are simultaneously connected to the molten salt inlet of the feedwater preheater, and regulating valves are installed at the molten salt outlets of the low-pressure steam generator and the feedwater reheater, the molten salt outlet of the feedwater preheater is connected to the molten salt inlet of the low-temperature molten salt storage tank, and a regulating valve is installed at the molten salt inlet of the low-temperature molten salt storage tank; The feed water inlet of the feed water preheater is connected to a desalted water pipe, and a No. 1 feed water pump and a regulating valve are installed on the desalted water pipe. The feed water outlet of the feed water preheater is connected to the feed water inlets of the low-pressure steam generator and the feed water reheater at the same time, and a regulating valve is installed at the feed water inlet of the low-pressure steam generator, and a No. 2 feed water pump and a regulating valve are installed at the feed water inlet of the feed water reheater. The steam outlet of the low-pressure steam generator is connected to the steam inlet of the low-pressure steam superheater, and the medium-pressure steam outlet of the low-pressure steam superheater is connected to the medium-pressure industrial steam supply. The steam inlet end of the steam main pipe is connected, and a regulating valve is installed at the medium-pressure steam outlet of the low-pressure steam superheater, the feedwater outlet of the feedwater reheater is connected to the feedwater inlet of the high-pressure steam generator, the steam outlet of the high-pressure steam generator is connected to the steam inlet of the high-pressure steam superheater, the high-pressure steam outlet of the high-pressure steam superheater is connected to the steam inlet end of the hot resteam pipe and the steam inlet end of the medium-pressure industrial steam supply main pipe through the first steam branch pipe and the second steam branch pipe, and regulating valves are installed on the first steam branch pipe and the second steam branch pipe.

[0009] Preferably, it also includes a steam pressure matcher and a steam pressure reducing device, the steam outlet of the steam cooling heat exchanger is connected to the high-pressure steam inlet of the steam pressure matcher and the steam inlet of the steam pressure reducing device at the same time, and regulating valves are installed at the high-pressure steam inlet of the steam pressure matcher and the steam inlet of the steam pressure reducing device, the steam outlet of the steam pressure reducing device is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe, the low-pressure steam inlet of the steam pressure matcher is connected to the industrial steam extraction port of the medium-pressure cylinder through the low-pressure industrial steam extraction pipe, and a regulating valve is installed on the low-pressure industrial steam extraction pipe, and the medium-pressure steam outlet of the steam pressure matcher is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe.

[0010] Preferably, a back pressure machine is also included, wherein the high-pressure steam outlet of the high-pressure steam superheater is connected to the steam inlet of the back pressure machine through a second steam branch pipe, the exhaust port of the back pressure machine is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe, and a regulating valve is installed at the exhaust port of the back pressure machine.

[0011] The present invention also provides an operation method of a power generation peak-shaving system of a heating unit coupled with molten salt heat storage, which is specifically as follows: When the system needs to reduce the on-grid power load to participate in power peak regulation, the low-temperature molten salt storage tank outputs the low-temperature molten salt and is heated up by the molten salt heat storage mechanism for secondary heating, and then returned to the high-temperature molten salt storage tank for storage, thereby achieving heat storage peak regulation. At this time: Open and adjust the corresponding valves. The low-temperature molten salt output from the low-temperature molten salt storage tank enters the steam cooling heat exchanger and the flue gas molten salt heat exchanger in two ways. They are heated by high-pressure steam and high-temperature flue gas for the first time, then output and merge and transported to the molten salt electric heater for the second heating by electric energy, and finally return to the high-temperature molten salt tank for heat storage; After being cooled by the steam cooling heat exchanger, the hot re-steam enters the steam pressure matcher and the steam pressure reducing device in two ways. One way of hot re-steam passes through the steam pressure matcher to match the pressure of the low-pressure industrial extraction steam from the medium-pressure cylinder and then outputs medium-pressure steam that meets the parameters required by the outside world. The other way of hot re-steam directly passes through the steam pressure reducing device to reduce the pressure and then outputs medium-pressure steam that meets the parameters required by the outside world. The medium-pressure steam generated by the steam pressure matcher and the steam pressure reducing device is then combined and output to the outside through the medium-pressure industrial steam supply mother pipe.

[0012] When the system needs to increase the on-grid power load to participate in power peak regulation, the high-temperature molten salt storage tank outputs high-temperature molten salt and passes through the molten salt heat release mechanism for three coolings before returning to the low-temperature molten salt storage tank for storage, thereby achieving heat release peak regulation. At this time: Open and adjust the corresponding valves. The high-temperature molten salt output from the high-temperature molten salt storage tank enters the high-pressure steam superheater and the high-pressure steam generator in turn to be cooled down for the first time, then outputs and enters the low-pressure steam superheater, the low-pressure steam generator and the feed water reheater in turn to be cooled down for the second time, then outputs and merges and enters the feed water preheater to be cooled down for the third time, and finally returns to the low-temperature molten salt storage tank to release heat; The feed water from the desalted water pipe is pressurized by the No. 1 feed water pump and then enters the feed water preheater to be heated by high-temperature molten salt for the first time, and then is output in two ways. One of the ways enters the low-pressure steam generator and the low-pressure steam superheater in turn to be heated by high-temperature molten salt to form medium-pressure steam with the parameters required by the outside world, and is output to the outside through the medium-pressure industrial steam supply mother pipe for supply steam to replace hot re-steam and low-pressure industrial extraction steam. The other way is pressurized again by the No. 2 feed water pump and enters the feed water reheater to be heated by high-temperature molten salt for the second time, and then is output and enters the high-pressure steam generator and the high-pressure steam superheater in turn to be heated by high-temperature molten salt to form high-pressure steam, and then is output in two ways. One of the ways enters the medium-pressure cylinder and the low-pressure cylinder in turn to do work and drive the generator to generate electricity, and the other way outputs medium-pressure steam with the parameters required by the outside world after doing work through the back pressure machine, and is output to the outside through the medium-pressure industrial steam supply mother pipe for supply steam to replace hot re-steam and low-pressure industrial extraction steam.

[0013] Preferably, when the system needs to reduce the on-grid power load to participate in power peak regulation, the steam cooling heat exchanger is preferentially used to heat the low-temperature molten salt to recover the high-temperature waste heat of the hot re-steam, and secondly, the flue gas molten salt heat exchanger is used to heat the low-temperature molten salt to recover the waste heat of the high-temperature flue gas, and finally, the molten salt electric heater is used to heat the low-temperature molten salt, so as to meet the external steam supply demand and the system power peak regulation requirements while improving the energy utilization efficiency of the system when reducing the on-grid power load for peak regulation.

[0014] Preferably, when the system needs to increase the on-grid power load to participate in power peak regulation, first, the molten salt heat release mechanism is used to generate medium-pressure steam with external parameters required by the outside world, which is used to replace hot re-steam and low-pressure industrial extraction steam, thereby increasing the system power generation load by re-entering the steam turbine unit to generate power; second, the high-pressure steam generated by the molten salt heat release mechanism is used to increase the system power generation load. At this time, high-pressure steam is preferentially used to enter the steam turbine unit to generate power to increase the system power generation load, and secondly, high-pressure steam is used to generate medium-pressure steam with external parameters required by the outside world after working through a back pressure machine, which is used to replace hot re-steam and low-pressure industrial extraction steam, thereby increasing the system power generation load by re-entering the steam turbine unit to generate power.

[0015] Compared with the prior art, the advantages and effects of the present invention include: first, when the molten salt heat storage peak-shaving device performs heat storage peak-shaving, the heat exchange process of coupling steam waste heat, flue gas waste heat and electric energy to heat the molten salt is reasonably designed, which not only recycles waste heat resources of different grades while ensuring external steam supply and electricity peak-shaving, but also realizes the cascade efficient utilization of energy of different grades, thereby improving the energy utilization efficiency of the molten salt heat storage process; second, when the molten salt heat storage peak-shaving device performs heat release peak-shaving, by reasonably designing a multi-stage heat exchange process of high-temperature molten salt heat release, it not only realizes the cascade efficient utilization of high-temperature molten salt thermal energy and reduces the work capacity loss in the heat exchange process, but also produces two different Parameters of steam, while meeting the needs of external steam supply and power peak regulation; third, the high-pressure steam generated by the high-temperature molten salt heat release process is returned to the steam turbine unit to generate power, which greatly improves the load capacity and rate of the unit, and can simultaneously meet the unit's load peak regulation and frequency regulation needs; fourth, by heating the molten salt by steam and flue gas to increase the energy efficiency of the heat storage process, the energy efficiency requirements of the system operation can be met, and by heating the molten salt by electric energy to increase the load reduction capacity and rate of the unit, the load reduction peak regulation and frequency regulation needs of the unit can be met at the same time, thereby by reasonably adjusting the proportion of different grades of energy heating molten salt, it can simultaneously meet the various needs of energy efficiency, peak regulation and frequency regulation. In addition, the key to the present invention is that when storing heat, the hot re-steam after heating the molten salt is used to supply steam to the outside, and when releasing heat, the medium-pressure steam generated by the high-temperature molten salt is used to supply steam to the outside, which also effectively solves the current thermal power unit. The four-stage extraction pressure is insufficient and cannot be directly supplied to the outside, and the hot re-steam pressure is too high, and the external steam supply will cause serious loss of work capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a power generation peak-shaving system of a heating unit coupled with molten salt heat storage in an embodiment of the present invention.

[0017] Figure 2 It is a schematic diagram of the structure of a power station boiler involved in an embodiment of the present invention.

[0018] In the figure: 1-power station boiler, 1001-superheater, 1002-reheater, 1003-economizer, 2-high pressure cylinder, 3-medium pressure cylinder, 4-low pressure cylinder, 5-generator, 6-condenser, 7-condensate pump, 8-low pressure regenerator, 9-deaerator, 10-boiler feed water pump, 11-medium pressure regenerator, 12-high pressure regenerator, 13-low temperature molten salt storage tank, 14-high temperature molten salt storage tank, 15-low temperature molten salt pump, 1 6-steam cooling heat exchanger, 17-flue gas molten salt heat exchanger, 18-molten salt electric heater, 19-high temperature molten salt pump, 20-high pressure steam superheater, 21-high pressure steam generator, 22-low pressure steam superheater, 23-low pressure steam generator, 24-feed water reheater, 25-feed water preheater, 26-No. 1 feed water pump, 27-No. 2 feed water pump, 28-back pressure machine, 29-steam pressure matcher, 30-steam pressure reducing device , 31-valve No. 1, 32-valve No. 2, 33-valve No. 3, 34-valve No. 4, 35-valve No. 5, 36-valve No. 6, 37-valve No. 7, 38-valve No. 8, 39-valve No. 9, 40-valve No. 10, 41-valve No. 11, 42-valve No. 12, 43-valve No. 13, 44-valve No. 14, 45-valve No. 15, 46-valve No. 16, 47-valve No. 17, 48-valve No. 18, 49-valve No. 19, 50-valve No. 20, 51-valve No. 21, 52-valve No. 22, 53-valve No. 23, 54-valve No. 24, 55-valve No. 25, 61-hot re-steam pipe, 62-low-pressure industrial extraction pipe, 63-medium-pressure industrial steam supply mother pipe, 64-hot re-steam branch pipe, 65-first steam branch pipe, 66-second steam branch pipe, 67-desalted water pipe. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and by way of examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0020] See also Figure 1The embodiment involves a power generation peak-shaving system of a heating unit coupled with molten salt heat storage, comprising: a power station boiler 1, a steam turbine unit, a molten salt heat storage peak-shaving device and a medium-pressure industrial steam supply mother pipe 63. The power station boiler 1 is sequentially arranged with a superheater 1001, a reheater 1002 and an economizer 1003 along the flue gas flow direction. The steam turbine unit comprises a high-pressure cylinder 2, a medium-pressure cylinder 3, a low-pressure cylinder 4, a generator 5, a condenser 6, a condensate pump 7, and a low-pressure regenerator. 8, deaerator 9, boiler feed water pump 10, medium-pressure reheater 11 and high-pressure reheater 12, the steam inlet of high-pressure cylinder 2 is connected to the steam outlet of superheater 1001, the steam outlet of high-pressure cylinder 2 is connected to the steam inlet of reheater 1002, the steam outlet of reheater 1002 is connected to the steam inlet of medium-pressure cylinder 3 through hot re-steam pipe 61, and a No. 1 valve 31 is installed on the hot re-steam pipe 61, the steam outlet of medium-pressure cylinder 3 is connected to the steam inlet of low-pressure cylinder 4 The exhaust port of the low-pressure cylinder 4 is connected to the exhaust steam inlet of the condenser 6, the high-pressure cylinder 2, the medium-pressure cylinder 3 and the low-pressure cylinder 4 are coaxially connected and drive the generator 5 to generate power, the condensate outlet of the condenser 6 is connected to the feed water inlet of the low-pressure regenerator 8 through the condensate pump 7, the feed water sides of the low-pressure regenerator 8, the deaerator 9, the boiler feed water pump 10, the medium-pressure regenerator 11 and the high-pressure regenerator 12 are connected in sequence along the water flow direction, the feed water outlet of the high-pressure regenerator 12 is connected to the feed water inlet of the power station boiler 1, the high-pressure cylinder 2 provides the steam required for heat recovery heating for the high-pressure regenerator 12, the medium-pressure cylinder 3 provides the steam required for heat recovery heating for the medium-pressure regenerator 11, the medium-pressure cylinder 3 also provides the steam required for water deoxygenation for the deaerator 9, the low-pressure cylinder 4 provides the steam required for heat recovery heating for the low-pressure regenerator 8, and the industrial steam extraction port of the medium-pressure cylinder 3 is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe 63 through the low-pressure industrial steam extraction pipe 62; In order to realize the heat storage and heat release of the molten salt heat storage peak-shaving device, the molten salt heat storage peak-shaving device includes a low-temperature molten salt storage tank 13, a high-temperature molten salt storage tank 14, a molten salt heat storage mechanism and a molten salt heat release mechanism. The molten salt inlet and the molten salt outlet of the molten salt heat storage mechanism are respectively connected to the molten salt outlet of the low-temperature molten salt storage tank 13 and the molten salt inlet of the high-temperature molten salt storage tank 14. The steam inlet of the molten salt heat storage mechanism is connected to the steam outlet of the reheater 1002 through the hot re-steam branch pipe 64, the steam outlet of the molten salt heat storage mechanism is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe 63, and the molten salt inlet and the molten salt outlet of the molten salt heat release mechanism are respectively connected to the high-temperature molten salt storage tank 14. The molten salt outlet is connected to the molten salt inlet of the low-temperature molten salt storage tank 13, the water inlet of the molten salt heat release mechanism is connected to the desalted water pipe 67, the medium-pressure steam outlet of the molten salt heat release mechanism is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe 67, and the high-pressure steam outlet of the molten salt heat release mechanism is connected to the steam inlet end of the hot re-steam pipe 61 and the steam inlet end of the medium-pressure industrial steam supply mother pipe 63 through the first steam branch pipe 65 and the second steam branch pipe 66, respectively. The flow direction of the medium in the molten salt pipeline of the molten salt heat storage mechanism is opposite to that of the medium in the steam pipeline, and the flow direction of the medium in the molten salt pipeline of the molten salt heat release mechanism is opposite to that of the medium in the steam pipeline and the medium in the water supply pipeline; In order to simultaneously improve the energy efficiency and peak-shaving capacity of the molten salt heat storage and peak-shaving device, the molten salt heat storage mechanism includes a first molten salt heat exchanger connected in series in two stages, the first molten salt heat exchanger includes a low-temperature molten salt pump 15, a steam cooling heat exchanger 16, a flue gas molten salt heat exchanger 17 and a molten salt electric heater 18, the first stage of the first molten salt heat exchanger uses the high-pressure steam in the steam cooling heat exchanger 16 and the high-temperature flue gas in the flue gas molten salt heat exchanger 17 to heat the low-temperature molten salt for the first time, the second stage of the first molten salt heat exchanger uses the electric energy in the molten salt electric heater 18 to heat the low-temperature molten salt for the second time, the molten salt heat release mechanism includes a second molten salt heat exchanger connected in series in three stages, the second molten salt heat exchanger includes a high-temperature molten salt pump 19, a high-pressure steam superheater 20, high-pressure steam generator 21, low-pressure steam superheater 22, low-pressure steam generator 23, feed water reheater 24, feed water preheater 25, No. 1 feed water pump 26 and No. 2 feed water pump 27, the first stage of the second molten salt heat exchanger uses the feed water preheater 25 to preheat the feed water to cool the high-temperature molten salt for the third time, the second stage of the second molten salt heat exchanger uses the low-pressure steam superheater 22 and the low-pressure steam generator 23 to produce medium-pressure steam, and uses the feed water reheater 24 to preheat part of the feed water for the second time to cool the high-temperature molten salt, the third stage of the second molten salt heat exchanger uses the high-pressure steam superheater 20 and the high-pressure steam generator 21 to produce high-pressure steam to cool the high-temperature molten salt for the first time.

[0021] like Figure 1 and Figure 2As shown, specifically, the connection method of each structure of the first molten salt heat exchanger is as follows: the molten salt sides of the steam cooling heat exchanger 16 and the flue gas molten salt heat exchanger 17 are connected in parallel, the molten salt sides of the steam cooling heat exchanger 16 or the flue gas molten salt heat exchanger 17 and the molten salt electric heater 18 are connected in series, the low-temperature molten salt pump 15 is arranged at the molten salt outlet of the low-temperature molten salt storage tank 13, and a No. 6 valve 36 is installed at the molten salt outlet of the low-temperature molten salt storage tank 13, the molten salt outlet of the low-temperature molten salt storage tank 13 is simultaneously connected to the molten salt inlets of the steam cooling heat exchanger 16 and the flue gas molten salt heat exchanger 17, and a No. 8 valve 38 and a No. 10 valve 40 are installed at the molten salt inlets of the steam cooling heat exchanger 16 and the flue gas molten salt heat exchanger 17 respectively, the molten salt outlets of the steam cooling heat exchanger 16 and the flue gas molten salt heat exchanger 17 are simultaneously connected to the molten salt inlet of the molten salt electric heater 18, and the steam The molten salt outlets of the cooling heat exchanger 16 and the flue gas molten salt heat exchanger 17 are respectively installed with valve No. 9 39 and valve No. 11 41, the molten salt outlet of the molten salt electric heater 18 is connected to the molten salt inlet of the high-temperature molten salt storage tank 14, and the molten salt inlet of the high-temperature molten salt storage tank 14 is installed with valve No. 12 42, the steam inlet of the steam cooling heat exchanger 16 is connected to the steam outlet of the reheater 1002 through the hot re-steam branch pipe 64, and valve No. 7 37 and valve No. 2 32 are respectively installed on the steam inlet of the steam cooling heat exchanger 16 and the hot re-steam branch pipe 64, the steam outlet of the steam cooling heat exchanger 16 is connected to the steam inlet end of the medium-pressure industrial steam supply main pipe 63, the flue gas molten salt heat exchanger 17 is arranged between the reheater 1002 and the economizer 1003 of the power plant boiler 1, and the electric energy used by the molten salt electric heater 18 to heat the low-temperature molten salt comes from the generator 5; The connection method of the second molten salt heat exchanger is as follows: the molten salt sides of the low-pressure steam generator 23 and the feed water reheater 24 are connected in parallel, and the molten salt sides of the high-pressure steam superheater 20, the high-pressure steam generator 21, the low-pressure steam superheater 22, the low-pressure steam generator 23 or the feed water reheater 24, and the feed water preheater 25 are connected in series in sequence, and the high-temperature molten salt pump 19 is arranged at the molten salt outlet of the high-temperature molten salt storage tank 14, and a No. 13 valve 43 is installed at the molten salt outlet of the high-temperature molten salt storage tank 14, the molten salt outlet of the high-temperature molten salt storage tank 14 is connected to the molten salt inlet of the high-pressure steam superheater 20, the molten salt outlet of the high-pressure steam superheater 20 is connected to the molten salt inlet of the high-pressure steam generator 21, and the high-pressure steam generator 21 is connected to the high-pressure steam generator 21. The molten salt outlet of the generator 21 is connected to the molten salt inlet of the low-pressure steam superheater 22, and the molten salt outlet of the low-pressure steam superheater 22 is connected to the molten salt inlets of the low-pressure steam generator 23 and the feed water reheater 24 at the same time, and the molten salt inlets of the low-pressure steam generator 23 and the feed water reheater 24 are respectively installed with a No. 16 valve 46 and a No. 18 valve 48, the molten salt outlets of the low-pressure steam generator 23 and the feed water reheater 24 are simultaneously connected to the molten salt inlet of the feed water preheater 25, and the molten salt outlets of the low-pressure steam generator 23 and the feed water reheater 24 are respectively installed with a No. 17 valve 47 and a No. 19 valve 49, the molten salt outlet of the feed water preheater 25 is connected to the molten salt inlet of the low-temperature molten salt storage tank 13. The feed water inlet of the feed water preheater 25 is connected to the feed water inlet of the low-pressure steam generator 23 and the feed water reheater 24, and a No. 22 valve 52 is installed at the feed water inlet of the low-pressure steam generator 23, and a No. 20 valve 50 is installed at the molten salt inlet of the low-temperature molten salt storage tank 13. The feed water inlet of the feed water preheater 25 is connected to the desalted water pipe 67, and a No. 1 feed water pump 26 and a No. 21 valve 51 are installed on the desalted water pipe 67. The feed water outlet of the feed water preheater 25 is connected to the feed water inlets of the low-pressure steam generator 23 and the feed water reheater 24 at the same time, and a No. 22 valve 52 is installed at the feed water inlet of the low-pressure steam generator 23, and a No. 2 feed water pump 27 and a No. 23 valve 53 are installed at the feed water inlet of the feed water reheater 24. The steam outlet of the low-pressure steam generator 23 is connected to the steam inlet of the low-pressure steam superheater 22, and the steam outlet of the low-pressure steam generator 23 is connected to the steam inlet of the low-pressure steam superheater 22. The medium-pressure steam outlet is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe 63, and a No. 24 valve 54 is installed at the medium-pressure steam outlet of the low-pressure steam superheater 22, the feed water outlet of the feed water reheater 24 is connected to the feed water inlet of the high-pressure steam generator 21, the steam outlet of the high-pressure steam generator 21 is connected to the steam inlet of the high-pressure steam superheater 20, and the high-pressure steam outlet of the high-pressure steam superheater 20 is connected to the steam inlet end of the hot reheat steam pipe 61 and the steam inlet end of the medium-pressure industrial steam supply mother pipe 63 through the first steam branch pipe 65 and the second steam branch pipe 66, and a No. 14 valve 44 and a No. 15 valve 45 are installed on the first steam branch pipe 65 and the second steam branch pipe 66 respectively.

[0022] like Figure 1As shown, in order to improve the flexibility of external steam supply, the system also includes a steam pressure matcher 29, a steam pressure reducing device 30 and a back pressure machine 28. The steam outlet of the steam cooling heat exchanger 16 is connected to the high-pressure steam inlet of the steam pressure matcher 29 and the steam inlet of the steam pressure reducing device 30 at the same time, and the high-pressure steam inlet of the steam pressure matcher 29 and the steam inlet of the steam pressure reducing device 30 are respectively installed with a No. 4 valve 34 and a No. 5 valve 35. The steam outlet of the steam pressure reducing device 30 is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe 63, and the low-pressure steam inlet of the steam pressure matcher 29 is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe 63. The low-pressure industrial steam extraction pipe 62 is connected to the industrial steam extraction port of the medium-pressure cylinder 3, and a No. 3 valve 33 is installed on the low-pressure industrial steam extraction pipe 62. The medium-pressure steam outlet of the steam pressure matcher 29 is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe 63. The steam inlet of the back pressure machine 28 is connected to the high-pressure steam outlet of the high-pressure steam superheater 20 through the second steam branch pipe 66. The exhaust port of the back pressure machine 28 is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe 63, and a No. 25 valve 55 is installed at the exhaust port of the back pressure machine 28. The back pressure machine 28 is used to drive the No. 1 feed water pump 26 and the No. 2 feed water pump 27 to do work.

[0023] The operation method of this embodiment is as follows: When the system needs to reduce the on-grid power load to participate in power peak regulation, the low-temperature molten salt storage tank 13 outputs the low-temperature molten salt and is heated for the second time by the molten salt heat storage mechanism, and then returned to the high-temperature molten salt storage tank 14 for storage, thereby realizing heat storage peak regulation. At this time, the corresponding valve is opened and adjusted, and the low-temperature molten salt output by the low-temperature molten salt storage tank 13 enters the steam cooling heat exchanger 16 and the flue gas molten salt heat exchanger 17 in two ways, and is heated by high-pressure steam and high-temperature flue gas for the first time respectively, and then output, merged and transported to the molten salt electric heater 18 for the second heating by electric energy, and finally returns to the high-temperature molten salt tank 14 for After the steam cooling heat exchanger 16 cools down the hot re-steam, it enters the steam pressure matcher 29 and the steam pressure reducing device 30 in two ways. One way of hot re-steam passes through the steam pressure matcher 29 to match the pressure of the low-pressure industrial extraction steam from the medium-pressure cylinder 3, and then outputs the medium-pressure steam that meets the parameters required by the outside world. The other way of hot re-steam directly passes through the steam pressure reducing device 30 to reduce the pressure, and then outputs the medium-pressure steam that meets the parameters required by the outside world. Then, the medium-pressure steam generated by the steam pressure matcher 29 and the steam pressure reducing device 30 is combined and then output to the outside through the medium-pressure industrial steam supply main pipe 63. At this time: The steam cooling heat exchanger 16 is preferentially used to heat the low-temperature molten salt to recover the high-temperature waste heat of the hot resteam. Secondly, the flue gas molten salt heat exchanger 17 is used to heat the low-temperature molten salt to recover the waste heat of the high-temperature flue gas. Finally, the molten salt electric heater 18 is used to heat the low-temperature molten salt. While meeting the external steam supply demand and the system power peak-shaving requirements, the energy utilization efficiency of the system is improved when reducing the peak load of the on-grid power.

[0024] When the system needs to increase the on-grid power load to participate in power peak regulation, the high-temperature molten salt storage tank 14 outputs high-temperature molten salt and passes through the molten salt heat release mechanism for three times of cooling and cooling, and then returns to the low-temperature molten salt storage tank 13 for storage, thereby realizing heat release and peak regulation. At this time, open and adjust the corresponding valves, and the high-temperature molten salt output by the high-temperature molten salt storage tank 14 enters the high-pressure steam superheater 20 and the high-pressure steam generator 21 in turn to be cooled and cooled for the first time, and then output and enter the low-pressure steam superheater 22, the low-pressure steam generator 23 and the feed water reheater 24 in turn to be cooled and cooled for the second time, and then output and merge and enter the feed water preheater 25 to be cooled and cooled for the third time, and finally returns to the low-temperature molten salt storage tank 13 to release heat. The feed water from the desalted water pipe 67 is pressurized by the No. 1 feed water pump 26 and enters the feed water preheater 25 to be heated by the high-temperature molten salt for the first time, and then After that, it is divided into two outputs, one of which enters the low-pressure steam generator 23 and the low-pressure steam superheater 22 in turn, and is heated by the high-temperature molten salt to form medium-pressure steam with the parameters required by the outside world, and is output to the outside through the medium-pressure industrial steam supply mother pipe 63 to replace hot re-steam and low-pressure industrial extraction steam, and the other is boosted again by the No. 2 feed water pump 27 and enters the feed water reheater 24 to be heated for the second time by the high-temperature molten salt, and then output and enter the high-pressure steam generator 21 and the high-pressure steam superheater 20 in turn to be heated by the high-temperature molten salt to form high-pressure steam, and then is divided into two outputs, one of which enters the medium-pressure cylinder 3 and the low-pressure cylinder 4 in turn to work and drive the generator 5 to generate electricity, and the other outputs the medium-pressure steam with the parameters required by the outside world after working by the back pressure machine 28, and is output to the outside through the medium-pressure industrial steam supply mother pipe 63 to replace hot re-steam and low-pressure industrial extraction steam. At this time: First, the molten salt heat release mechanism is used to generate medium-pressure steam with parameters required by the outside world, which is used to replace hot resteam and low-pressure industrial extraction steam. The replaced hot resteam and low-pressure industrial extraction steam re-enter the steam turbine unit to generate power, thereby increasing the system power generation load; The second is to use the high-pressure steam generated by the molten salt heat release mechanism to increase the system's power generation load. At this time, the high-pressure steam is preferentially used to enter the steam turbine unit to generate power to increase the system's power generation load. Secondly, the high-pressure steam is used to generate medium-pressure steam with the parameters required by the outside world after working through the back pressure machine, which is used to replace hot resteam and low-pressure industrial extraction steam. In this way, the replaced hot resteam and low-pressure industrial extraction steam re-enter the steam turbine unit to generate power to increase the system's power generation load.

[0025] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the present invention. All equivalent changes or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. Technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A power generation peak-shaving system of a heating unit coupled with molten salt heat storage, comprising: A power station boiler and a steam turbine unit, wherein a superheater, a reheater and an economizer are arranged in sequence along the direction of flue gas flow in the power station boiler, and the steam turbine unit comprises a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, a generator, a condenser, a condensate pump, a low-pressure reheater, a deaerator, a boiler feed water pump, a medium-pressure reheater and a high-pressure reheater, the steam inlet of the high-pressure cylinder is connected to the steam outlet of the superheater, the steam outlet of the high-pressure cylinder is connected to the steam inlet of the reheater, the steam outlet of the reheater is connected to the steam inlet of the medium-pressure cylinder through a hot re-steam pipe, and a regulating valve is installed on the hot re-steam pipe, the steam outlet of the medium-pressure cylinder is connected to the steam inlet of the low-pressure cylinder, The exhaust port of the low-pressure cylinder is connected to the exhaust steam inlet of the condenser, the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder are coaxially connected and drive the generator to generate power, the condensate outlet of the condenser is connected to the feed water inlet of the low-pressure regenerator through the condensate pump, the feed water sides of the low-pressure regenerator, the deaerator, the boiler feed water pump, the medium-pressure regenerator and the high-pressure regenerator are connected in sequence along the water flow direction, the feed water outlet of the high-pressure regenerator is connected to the feed water inlet of the power station boiler, the high-pressure cylinder provides the required steam for the high-pressure regenerator, the medium-pressure cylinder provides the required steam for the medium-pressure regenerator and the deaerator, and the low-pressure cylinder provides the required steam for the low-pressure regenerator; It is characterized in that it also includes: a molten salt heat storage peak-shaving device and a medium-pressure industrial steam supply mother pipe, the molten salt heat storage peak-shaving device includes a low-temperature molten salt storage tank, a high-temperature molten salt storage tank, a molten salt heat storage mechanism and a molten salt heat release mechanism, and the industrial steam extraction port of the medium-pressure cylinder is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe through a low-pressure industrial steam extraction pipe; The molten salt inlet and the molten salt outlet of the molten salt heat storage mechanism are connected to the molten salt outlet of the low-temperature molten salt storage tank and the molten salt inlet of the high-temperature molten salt storage tank respectively, the steam inlet of the molten salt heat storage mechanism is connected to the steam outlet of the reheater through the hot re-steam branch pipe, the steam outlet of the molten salt heat storage mechanism is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe, the molten salt inlet and the molten salt outlet of the molten salt heat release mechanism are connected to the molten salt outlet of the high-temperature molten salt storage tank and the molten salt inlet of the low-temperature molten salt storage tank respectively, the feed water inlet of the molten salt heat release mechanism is connected with a desalted water pipe, the medium-pressure steam outlet of the molten salt heat release mechanism is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe, and the high-pressure steam outlet of the molten salt heat release mechanism is connected to the steam inlet end of the hot re-steam pipe and the steam inlet end of the medium-pressure industrial steam supply mother pipe through the first steam branch pipe and the second steam branch pipe respectively; The molten salt heat storage mechanism comprises two stages of first molten salt heat exchangers connected in series, the first stage of the first molten salt heat exchanger uses high-pressure steam and high-temperature flue gas to heat low-temperature molten salt at the same time, and the second stage of the first molten salt heat exchanger uses electric energy to heat low-temperature molten salt; The molten salt heat release mechanism comprises three stages of second molten salt heat exchangers connected in series, the first stage of the second molten salt heat exchanger uses high-temperature molten salt to preheat feed water, the second stage of the second molten salt heat exchanger uses high-temperature molten salt to produce medium-pressure steam and preheat part of the feed water for a second time, and the third stage of the second molten salt heat exchanger uses high-temperature molten salt to produce high-pressure steam; The medium in the molten salt pipeline of the molten salt heat storage mechanism flows in opposite directions to the medium in the steam pipeline, and the medium in the molten salt pipeline of the molten salt heat release mechanism flows in opposite directions to the medium in the steam pipeline and the medium in the water supply pipeline.

2. According to claim 1, a power generation peak-shaving system of a heating unit coupled with molten salt heat storage is characterized in that: The first molten salt heat exchanger comprises a low-temperature molten salt pump, a steam cooling heat exchanger, a flue gas molten salt heat exchanger and a molten salt electric heater. The first stage of the first molten salt heat exchanger utilizes the steam cooling heat exchanger and the flue gas molten salt heat exchanger to heat the low-temperature molten salt for the first time. The second stage of the first molten salt heat exchanger utilizes the molten salt electric heater to heat the low-temperature molten salt for the second time. The molten salt sides of the steam cooling heat exchanger and the flue gas molten salt heat exchanger are connected in parallel, and the molten salt sides of the steam cooling heat exchanger or the flue gas molten salt heat exchanger and the molten salt electric heater are connected in series. The low-temperature molten salt pump is arranged at the molten salt outlet of the low-temperature molten salt storage tank, and a regulating valve is installed at the molten salt outlet of the low-temperature molten salt storage tank, the molten salt outlet of the low-temperature molten salt storage tank is simultaneously connected to the molten salt inlet of the steam cooling heat exchanger and the flue gas molten salt heat exchanger, and regulating valves are installed at the molten salt inlets of the steam cooling heat exchanger and the flue gas molten salt heat exchanger, the molten salt outlets of the steam cooling heat exchanger and the flue gas molten salt heat exchanger are simultaneously connected to the molten salt inlet of the molten salt electric heater, and regulating valves are installed at the molten salt outlets of the steam cooling heat exchanger and the flue gas molten salt heat exchanger, the molten salt outlet of the molten salt electric heater is connected to the molten salt inlet of the high-temperature molten salt storage tank, and a regulating valve is installed at the molten salt inlet of the high-temperature molten salt storage tank; The steam inlet of the steam cooling heat exchanger is connected to the steam outlet of the reheater through a hot re-steam branch pipe, and regulating valves are installed on the steam inlet and the hot re-steam branch pipe of the steam cooling heat exchanger. The steam outlet of the steam cooling heat exchanger is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe. The flue gas molten salt heat exchanger is arranged between the reheater and the economizer of the power station boiler. The electric energy of the molten salt electric heater for heating the low-temperature molten salt comes from the generator.

3. The peak-shaving power generation system of a heating unit coupled with molten salt heat storage according to claim 1 is characterized in that: The second molten salt heat exchanger comprises a high-temperature molten salt pump, a high-pressure steam superheater, a high-pressure steam generator, a low-pressure steam superheater, a low-pressure steam generator, a feedwater reheater, a feedwater preheater, a No. 1 feedwater pump and a No. 2 feedwater pump. The first stage of the second molten salt heat exchanger uses the feedwater preheater to preheat the feedwater to cool the high-temperature molten salt for the third time. The second stage of the second molten salt heat exchanger uses the low-pressure steam superheater and the low-pressure steam generator to produce medium-pressure steam, and uses the feedwater reheater to preheat part of the feedwater for the second time to cool the high-temperature molten salt. The third stage of the second molten salt heat exchanger uses the high-pressure steam superheater and the high-pressure steam generator to produce high-pressure steam to cool the high-temperature molten salt for the first time. The molten salt sides of the low-pressure steam generator and the feedwater reheater are connected in parallel, and the molten salt sides of the high-pressure steam superheater, the high-pressure steam generator, the low-pressure steam superheater, the low-pressure steam generator or the feedwater reheater and the feedwater preheater are connected in series in sequence. The high-temperature molten salt pump is arranged at the molten salt outlet of the high-temperature molten salt storage tank, and a regulating valve is installed at the molten salt outlet of the high-temperature molten salt storage tank, the molten salt outlet of the high-temperature molten salt storage tank is connected to the molten salt inlet of the high-pressure steam superheater, the molten salt outlet of the high-pressure steam superheater is connected to the molten salt inlet of the high-pressure steam generator, the molten salt outlet of the high-pressure steam generator is connected to the molten salt inlet of the low-pressure steam superheater, the molten salt outlet of the low-pressure steam superheater is simultaneously connected to the molten salt inlets of the low-pressure steam generator and the feedwater reheater, and regulating valves are installed at the molten salt inlets of the low-pressure steam generator and the feedwater reheater, the molten salt outlets of the low-pressure steam generator and the feedwater reheater are simultaneously connected to the molten salt inlet of the feedwater preheater, and regulating valves are installed at the molten salt outlets of the low-pressure steam generator and the feedwater reheater, the molten salt outlet of the feedwater preheater is connected to the molten salt inlet of the low-temperature molten salt storage tank, and a regulating valve is installed at the molten salt inlet of the low-temperature molten salt storage tank; The feed water inlet of the feed water preheater is connected to a desalted water pipe, and a No. 1 feed water pump and a regulating valve are installed on the desalted water pipe. The feed water outlet of the feed water preheater is connected to the feed water inlets of the low-pressure steam generator and the feed water reheater at the same time, and a regulating valve is installed at the feed water inlet of the low-pressure steam generator, and a No. 2 feed water pump and a regulating valve are installed at the feed water inlet of the feed water reheater. The steam outlet of the low-pressure steam generator is connected to the steam inlet of the low-pressure steam superheater, and the medium-pressure steam outlet of the low-pressure steam superheater is connected to the medium-pressure industrial steam supply. The steam inlet end of the steam main pipe is connected, and a regulating valve is installed at the medium-pressure steam outlet of the low-pressure steam superheater, the feedwater outlet of the feedwater reheater is connected to the feedwater inlet of the high-pressure steam generator, the steam outlet of the high-pressure steam generator is connected to the steam inlet of the high-pressure steam superheater, the high-pressure steam outlet of the high-pressure steam superheater is connected to the steam inlet end of the hot resteam pipe and the steam inlet end of the medium-pressure industrial steam supply main pipe through the first steam branch pipe and the second steam branch pipe, and regulating valves are installed on the first steam branch pipe and the second steam branch pipe.

4. The peak-shaving power generation system of a heating unit coupled with molten salt heat storage according to claim 1, characterized in that: It also includes a steam pressure matcher and a steam pressure reducing device, the steam outlet of the steam cooling heat exchanger is connected to the high-pressure steam inlet of the steam pressure matcher and the steam inlet of the steam pressure reducing device at the same time, and regulating valves are installed at the high-pressure steam inlet of the steam pressure matcher and the steam inlet of the steam pressure reducing device, the steam outlet of the steam pressure reducing device is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe, the low-pressure steam inlet of the steam pressure matcher is connected to the industrial steam extraction port of the medium-pressure cylinder through the low-pressure industrial steam extraction pipe, and a regulating valve is installed on the low-pressure industrial steam extraction pipe, and the medium-pressure steam outlet of the steam pressure matcher is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe.

5. The peak-shaving power generation system of a heating unit coupled with molten salt heat storage according to claim 1, characterized in that: It also includes a back pressure machine, the high-pressure steam outlet of the high-pressure steam superheater is connected to the steam inlet of the back pressure machine through a second steam branch pipe, the exhaust port of the back pressure machine is connected to the steam inlet end of the medium-pressure industrial steam supply mother pipe, and a regulating valve is installed at the exhaust port of the back pressure machine.

6. An operating method of a power generation peak-shaving system of a heating unit coupled with molten salt heat storage according to any one of claims 1 to 5, characterized in that: Here’s how to run it: When the system needs to reduce the on-grid power load to participate in power peak regulation, the low-temperature molten salt storage tank outputs the low-temperature molten salt and is heated up by the molten salt heat storage mechanism for secondary heating, and then returned to the high-temperature molten salt storage tank for storage, thereby achieving heat storage peak regulation. At this time: Open and adjust the corresponding valves. The low-temperature molten salt output from the low-temperature molten salt storage tank enters the steam cooling heat exchanger and the flue gas molten salt heat exchanger in two ways. They are heated by high-pressure steam and high-temperature flue gas for the first time, then output and merge and transported to the molten salt electric heater for the second heating by electric energy, and finally return to the high-temperature molten salt tank for heat storage; After being cooled by the steam cooling heat exchanger, the hot re-steam enters the steam pressure matcher and the steam pressure reducing device in two ways. One way of hot re-steam passes through the steam pressure matcher to match the pressure of the low-pressure industrial extraction steam from the medium-pressure cylinder and then outputs medium-pressure steam that meets the parameters required by the outside world. The other way of hot re-steam directly passes through the steam pressure reducing device to reduce the pressure and then outputs medium-pressure steam that meets the parameters required by the outside world. The medium-pressure steam generated by the steam pressure matcher and the steam pressure reducing device is then combined and output to the outside through the medium-pressure industrial steam supply main pipe. When the system needs to increase the on-grid power load to participate in power peak regulation, the high-temperature molten salt storage tank outputs high-temperature molten salt and passes through the molten salt heat release mechanism for three coolings before returning to the low-temperature molten salt storage tank for storage, thereby achieving heat release peak regulation. At this time: Open and adjust the corresponding valves. The high-temperature molten salt output from the high-temperature molten salt storage tank enters the high-pressure steam superheater and the high-pressure steam generator in turn to be cooled down for the first time, then outputs and enters the low-pressure steam superheater, the low-pressure steam generator and the feed water reheater in turn to be cooled down for the second time, then outputs and merges and enters the feed water preheater to be cooled down for the third time, and finally returns to the low-temperature molten salt storage tank to release heat; The feed water from the desalted water pipe is pressurized by the No. 1 feed water pump and then enters the feed water preheater to be heated by high-temperature molten salt for the first time, and then is output in two ways. One of the ways enters the low-pressure steam generator and the low-pressure steam superheater in turn to be heated by high-temperature molten salt to form medium-pressure steam with the parameters required by the outside world, and is output to the outside through the medium-pressure industrial steam supply mother pipe for supply steam to replace hot re-steam and low-pressure industrial extraction steam. The other way is pressurized again by the No. 2 feed water pump and enters the feed water reheater to be heated by high-temperature molten salt for the second time, and then is output and enters the high-pressure steam generator and the high-pressure steam superheater in turn to be heated by high-temperature molten salt to form high-pressure steam, and then is output in two ways. One of the ways enters the medium-pressure cylinder and the low-pressure cylinder in turn to do work and drive the generator to generate electricity, and the other way outputs medium-pressure steam with the parameters required by the outside world after doing work through the back pressure machine, and is output to the outside through the medium-pressure industrial steam supply mother pipe for supply steam to replace hot re-steam and low-pressure industrial extraction steam.

7. The method for operating a peak-shaving power generation system of a heating unit coupled with molten salt heat storage according to claim 6, characterized in that: When the system needs to reduce the on-grid power load to participate in power peak regulation, the steam cooling heat exchanger is preferentially used to heat the low-temperature molten salt to recover the high-temperature waste heat of the hot re-steam. Secondly, the flue gas molten salt heat exchanger is used to heat the low-temperature molten salt to recover the waste heat of the high-temperature flue gas. Finally, the molten salt electric heater is used to heat the low-temperature molten salt. While meeting the external steam supply demand and the system power peak regulation requirements, the energy utilization efficiency of the system is improved when reducing the on-grid power load for peak regulation.

8. The method for operating a peak-shaving power generation system of a heating unit coupled with molten salt heat storage according to claim 6, characterized in that: When the system needs to increase the on-grid power load to participate in power peak regulation, first, the molten salt heat release mechanism is used to generate medium-pressure steam with external parameters required by the outside world, which is used to replace hot re-steam and low-pressure industrial extraction steam, thereby increasing the system power generation load by re-entering the steam turbine unit to generate power; second, the high-pressure steam generated by the molten salt heat release mechanism is used to increase the system power generation load. At this time, high-pressure steam is preferentially used to enter the steam turbine unit to generate power to increase the system power generation load, and secondly, high-pressure steam is used to generate medium-pressure steam with external parameters required by the outside world after working through the back pressure machine, which is used to replace hot re-steam and low-pressure industrial extraction steam, thereby increasing the system power generation load by re-entering the steam turbine unit to generate power.

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