CN117239821A - Power grid peak shaving system - Google Patents

Abstract

The application relates to the technical field of power generation, in particular to a power grid peak shaving system, which comprises the following components: when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is larger than the electric quantity required by the power grid, the solar photo-thermal power generation subsystem stores heat in the fused salt Chu Fangre subsystem and is used for generating power by the steam turbine generator unit; when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is equal to the electric quantity required by the power grid, the solar photo-thermal power generation subsystem uses all heat to generate power by the steam turbine generator unit; when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is smaller than the electric quantity required by the power grid, the solar photo-thermal power generation subsystem uses heat for the steam turbine generator unit to generate power, and the fused salt Chu Fangre subsystem uses heat for the steam turbine generator unit to generate power; according to the relation between the photo-thermal power generation amount of the solar photo-thermal power generation subsystem and the electric quantity required by the electric network, the solar photo-thermal power generation subsystem is matched with the fused salt Chu Fangre subsystem to store and release energy timely, so that the peak regulation requirement of the electric network is completed.

Description

Power grid peak shaving system

Technical Field

The application relates to the technical field of power generation, in particular to a power grid peak shaving system.

Background

In the "two carbon" background, the installed capacity of renewable energy power generation represented by solar energy continues to increase. However, the fluctuation and intermittence of the solar energy prevent the solar energy from being connected in a large scale, and serious light rejection is caused. As a high-efficiency power generation mode, the gas turbine-steam combined cycle unit has the advantages of high heat power conversion efficiency, low construction cost, high response speed and the like. Therefore, the peak shaving of the gas turbine-steam combined cycle unit is adopted, and an effective mode is provided for the stable operation of the solar photo-thermal generator unit and the enhancement of the photo-thermal power generation and absorption capacity of the power grid.

However, peak shaving of the combined cycle unit is mainly achieved by start-up, shut-down and low load operation. The key components of the gas turbine-steam combined cycle unit are damaged due to thermal fatigue caused by frequent start and stop, so that the service life is greatly reduced; and the heat consumption rate is increased during low-load operation, so that the economy is reduced.

Disclosure of Invention

Therefore, the invention aims to solve the technical problems that the peak regulation of the combined cycle unit of the combustion engine and the steam is adopted independently, the key components of the combined cycle unit of the combustion engine and the steam are damaged due to thermal fatigue caused by frequent start and stop, and the service life is greatly reduced; and the heat consumption rate is increased during low-load operation, and the economical efficiency is reduced.

In order to overcome the above-mentioned drawbacks, the present invention provides a power grid peak shaving system, comprising:

a solar photo-thermal power generation subsystem;

a gas-steam combined cycle subsystem;

the fused salt Chu Fangre subsystem is connected with the solar photo-thermal power generation subsystem;

the steam turbine generator unit is connected with the solar photo-thermal power generation subsystem and the molten salt heat storage and release subsystem, and is connected to a power grid;

the power grid peak shaving system is provided with a first state that when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is larger than the power required by a power grid, the solar photo-thermal power generation subsystem stores part of heat in the fused salt Chu Fangre subsystem, and the solar photo-thermal power generation subsystem uses the other part of heat for the power generation of the turbo generator set; and a second state in which the solar photo-thermal power generation subsystem uses all heat for the steam turbine generator unit to generate power when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is equal to the power required by the power grid; when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is smaller than the electric quantity required by the electric network, the solar photo-thermal power generation subsystem uses heat for the steam turbine generator unit to generate power, and the fused salt Chu Fangre subsystem uses heat for a third state of the steam turbine generator unit to generate power;

And under the first state, the second state and the third state, the gas-steam combined cycle subsystem stops working.

Optionally, the method further comprises:

the first generator is connected with the gas-steam combined cycle subsystem and is connected to a power grid; the gas-steam combined circulation subsystem is connected with the steam turbine generator unit and the molten salt heat storage and release subsystem;

the electric heater is connected with the first generator, the molten salt heat storage and release subsystem and the steam turbine generator unit; the electric heater is adapted to heat molten salt in the molten salt Chu Fangre subsystem;

the power grid peak shaving system is in a fourth state that the gas-steam combined cycle subsystem drives the steam turbine generator unit to generate power when the power grid requirement is equal to the full-load power generation capacity of the gas-steam combined cycle subsystem; and a fifth state having a gas-steam combined cycle subsystem storing a portion of the heat in a molten salt Chu Fangre subsystem when the grid demand is equal to the low load power generation of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem utilizing another portion of the heat for steam turbine generator unit power generation; when the power grid requirement is equal to zero load power generation of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem stores a part of heat in the fused salt Chu Fangre subsystem, the gas-steam combined cycle subsystem uses another part of heat for generating power by the turbo generator set, the first generator and the turbo generator set supply power for the electric heater, and the electric heater stores the heated fused salt to a sixth state of the fused salt heat storage and release subsystem; when the power grid demand is equal to the overload power generation amount of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem drives the steam turbine generator unit to generate power, and the heat of the fused salt Chu Fangre subsystem is used for a seventh state of the steam turbine generator unit to generate power;

And in the fourth state, the fifth state, the sixth state and the seventh state, the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is zero, and the gas-steam combined cycle subsystem drives the first power generator to generate power.

Optionally, the method further comprises:

the phase-change heat storage tank is connected with the gas-steam combined cycle subsystem and is suitable for storing part of heat of the gas-steam combined cycle subsystem in a fourth state, a fifth state, a sixth state and a seventh state so as to supply heat for users.

Optionally, the solar photo-thermal power generation subsystem includes: heliostat field and heat absorber;

the heliostat field is suitable for receiving sunlight of the sun and reflecting the sunlight to the heat absorber; the heat absorber is adapted to absorb sunlight reflected by a heliostat field and convert it into thermal energy.

Optionally, the molten salt Chu Fangre subsystem comprises:

the inlet of the first molten salt tank is connected with the outlet of the heat absorber;

the second heat exchanger is connected with the outlet of the heat absorber, the outlet of the first molten salt tank and the steam turbine generator unit;

the second molten salt tank is connected with inlets of the second heat exchanger and the heat absorber;

the heat absorber is suitable for heating molten salt conveyed by the second molten salt tank and conveying the heated molten salt to the first molten salt tank or the second heat exchanger;

The second heat exchanger is suitable for exchanging heat between molten salt and water, and conveying the heated water to the turbo generator set for power generation, and conveying the cooled molten salt to the heat absorber.

Optionally, the gas-steam combined cycle subsystem comprises:

the compressor, the combustion chamber and the turbine are connected in sequence;

the first heat exchanger is connected with the turbine, the first molten salt tank and the second molten salt tank;

the compressor is adapted to introduce air;

the combustion chamber is suitable for introducing fuel and combusting air conveyed by the air compressor with the fuel to form fuel gas;

the turbine is suitable for receiving the fuel gas transmitted by the combustion chamber and driving the first generator to rotate for generating electricity;

the first heat exchanger is suitable for receiving the turbine fuel gas, exchanging heat between the molten salt from the second molten salt tank and the fuel gas, and conveying the heated molten salt to the first molten salt tank.

Optionally, the turbo generator set includes: the steam turbine and the second generator are connected;

the grid peak shaving system further comprises: the condenser, the water pump and the deaerator are connected in sequence;

the condenser is connected with the steam turbine, and the deaerator is connected with the second heat exchanger.

Optionally, the gas-steam combined cycle subsystem further comprises:

One end of the waste heat boiler is connected with the turbine, and the other end of the waste heat boiler is connected with the phase-change heat storage tank; the deaerator is also connected with a waste heat boiler, and the waste heat boiler is also connected with a steam turbine.

Optionally, the gas-steam combined cycle subsystem further comprises:

the heat regenerator is arranged between the gas compressor and the combustion chamber, one end of the heat regenerator is connected with the first heat exchanger, and the other end of the heat regenerator is connected with the phase-change heat storage tank.

Optionally, the method further comprises:

the control center is connected with the solar photo-thermal power generation subsystem, the gas-steam combined circulation subsystem, the molten salt heat storage subsystem and the power grid; the control center is suitable for acquiring the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem, the power grid demand and the load of the gas-steam combined cycle subsystem, and controlling the solar photo-thermal power generation subsystem, the gas-steam combined cycle subsystem and the molten salt heat storage and release subsystem to work cooperatively.

Compared with the prior art, the technical scheme of the application has the following advantages:

1. the power grid peak shaving system provided by the application comprises the following components: a solar photo-thermal power generation subsystem; a gas-steam combined cycle subsystem; the fused salt Chu Fangre subsystem is connected with the solar photo-thermal power generation subsystem; the steam turbine generator unit is connected with the solar photo-thermal power generation subsystem and the molten salt heat storage and release subsystem, and is connected to a power grid; the power grid peak shaving system is provided with a first state that when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is larger than the power required by a power grid, the solar photo-thermal power generation subsystem stores part of heat in the fused salt Chu Fangre subsystem, and the solar photo-thermal power generation subsystem uses the other part of heat for the power generation of the turbo generator set; and a second state in which the solar photo-thermal power generation subsystem uses all heat for the steam turbine generator unit to generate power when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is equal to the power required by the power grid; when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is smaller than the electric quantity required by the electric network, the solar photo-thermal power generation subsystem uses heat for the steam turbine generator unit to generate power, and the fused salt Chu Fangre subsystem uses heat for a third state of the steam turbine generator unit to generate power; under the first state, the second state and the third state, the gas-steam combined cycle subsystem stops working; by adopting the technical scheme, according to the relationship between the photo-thermal power generation amount of the solar photo-thermal power generation subsystem and the electric quantity required by the power grid, the solar photo-thermal power generation subsystem is matched with the fused salt Chu Fangre subsystem to store and release energy timely, so that the change of the electric quantity required by the power grid is reasonably met, and the peak regulation requirement of the power grid is completed; the peak regulation of the combined cycle unit of the combustion engine and the steam is avoided, key components of the combined cycle unit of the combustion engine and the steam are damaged due to thermal fatigue caused by frequent start and stop, and the service life is greatly reduced; and the heat consumption rate is increased during low-load operation, and the economical efficiency is reduced. The utilization rate of solar energy is improved, molten salt is utilized for storage when the solar energy is sufficient, and release is carried out when the solar energy is insufficient, so that the light discarding problem is effectively relieved; the maximum utilization rate of light and heat is ensured.

2. The power grid peak shaving system provided by the application further comprises: the first generator is connected with the gas-steam combined cycle subsystem and is connected to a power grid; the gas-steam combined circulation subsystem is connected with the steam turbine generator unit and the molten salt heat storage and release subsystem; the electric heater is connected with the first generator, the molten salt heat storage and release subsystem and the steam turbine generator unit; the electric heater is adapted to heat molten salt in the molten salt Chu Fangre subsystem; the power grid peak shaving system is in a fourth state that the gas-steam combined cycle subsystem drives the steam turbine generator unit to generate power when the power grid requirement is equal to the full-load power generation capacity of the gas-steam combined cycle subsystem; and a fifth state having a gas-steam combined cycle subsystem storing a portion of the heat in a molten salt Chu Fangre subsystem when the grid demand is equal to the low load power generation of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem utilizing another portion of the heat for steam turbine generator unit power generation; when the power grid requirement is equal to zero load power generation of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem stores a part of heat in the fused salt Chu Fangre subsystem, the gas-steam combined cycle subsystem uses another part of heat for generating power by the turbo generator set, the first generator and the turbo generator set supply power for the electric heater, and the electric heater stores the heated fused salt to a sixth state of the fused salt heat storage and release subsystem; when the power grid demand is equal to the overload power generation amount of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem drives the steam turbine generator unit to generate power, and the heat of the fused salt Chu Fangre subsystem is used for a seventh state of the steam turbine generator unit to generate power; in the fourth state, the fifth state, the sixth state and the seventh state, the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is zero, and the gas-steam combined cycle subsystem drives the first power generator to generate power; by adopting the technical scheme, when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is zero, the gas-steam combined circulation subsystem is matched with the fused salt Chu Fangre subsystem and the electric heater according to the power grid demand, so that energy is timely stored and discharged, the power grid demand change is reasonably met, and the peak regulation capacity of the power grid is improved. And the operation stability of the gas-steam combined cycle subsystem is improved, and the heat consumption rate is reduced.

3. The power grid peak shaving system provided by the application further comprises: the phase-change heat storage tank is connected with the fuel gas-steam combined cycle subsystem and is suitable for storing part of heat of the fuel gas-steam combined cycle subsystem in a fourth state, a sixth state and a seventh state so as to supply heat for a user; by adopting the technical scheme, the heat energy in the residual low-temperature fuel gas is reasonably stored and recovered through the phase-change heat storage tank, so that heat is supplied to users, the heat energy is utilized in a cascade manner, the energy is saved, and the cost is reduced; namely, the utilization efficiency of heat energy is improved, and the economical efficiency is enhanced.

4. The solar photo-thermal power generation subsystem of the application comprises: heliostat field and heat absorber; the heliostat field is suitable for receiving sunlight of the sun and reflecting the sunlight to the heat absorber; the heat absorber is suitable for absorbing sunlight reflected by the heliostat field and converting the sunlight into heat energy; by adopting the technical scheme, the solar energy is fully utilized and converted into heat energy for utilization.

5. The fused salt Chu Fangre subsystem of the application comprises: the inlet of the first molten salt tank is connected with the outlet of the heat absorber; the second heat exchanger is connected with the outlet of the heat absorber, the outlet of the first molten salt tank and the steam turbine generator unit; the second molten salt tank is connected with inlets of the second heat exchanger and the heat absorber; the heat absorber is suitable for heating molten salt conveyed by the second molten salt tank and conveying the heated molten salt to the first molten salt tank or the second heat exchanger; the second heat exchanger is suitable for exchanging heat between molten salt and water, conveying the heated water to a turbo generator set for power generation, and conveying the cooled molten salt to the heat absorber; by adopting the technical scheme, the heat absorber heats molten salt; and conveying a part of heated molten salt to a first molten salt tank for storage, conveying the other part of heated molten salt to a second heat exchanger, heating water into superheated steam, and entering a turbo generator set for acting and generating electricity.

6. The gas-steam combined cycle subsystem of the application comprises: the compressor, the combustion chamber and the turbine are connected in sequence; the first heat exchanger is connected with the turbine, the first molten salt tank and the second molten salt tank; the compressor is adapted to introduce air; the combustion chamber is suitable for introducing fuel and combusting air conveyed by the air compressor with the fuel to form fuel gas; the turbine is suitable for receiving the fuel gas transmitted by the combustion chamber and driving the first generator to rotate for generating electricity; the first heat exchanger is suitable for receiving the turbine fuel gas, exchanging heat between the molten salt from the second molten salt tank and the fuel gas, and conveying the heated molten salt to the first molten salt tank; by adopting the technical scheme, air is compressed by the air compressor and then burnt with fuel in the combustion chamber to generate high-temperature high-pressure fuel gas, and the high-temperature high-pressure fuel gas enters the turbine to do work so as to drive the first generator to generate electricity; and (3) the high-temperature low-pressure gas after the turbine does work enters a first heat exchanger, and molten salt is heated.

7. The steam turbine generator unit of the application comprises: the steam turbine and the second generator are connected; the grid peak shaving system further comprises: the condenser, the water pump and the deaerator are connected in sequence; the condenser is connected with the steam turbine, and the deaerator is connected with the second heat exchanger; by adopting the technical scheme, the exhaust gas after the turbine finishes acting enters the condenser to be cooled into condensed water; pressurizing by a water pump, and entering into a deaerator to remove oxygen and other gases dissolved in water, so as to prevent or weaken corrosion to pipelines and equipment; then, the water enters the second heat exchanger again for the next circulation; saving water resources and reducing cost.

8. The gas-steam combined cycle subsystem of the application further comprises: one end of the waste heat boiler is connected with the turbine, and the other end of the waste heat boiler is connected with the phase-change heat storage tank; the deaerator is also connected with a waste heat boiler, and the waste heat boiler is also connected with a steam turbine; by adopting the technical scheme, the high-temperature low-pressure gas after turbine working is finished enters the waste heat boiler to heat water, and the gas after heat exchange is finished enters the phase change heat storage tank to store the residual heat; after being heated into superheated steam by high-temperature fuel gas in the waste heat boiler, the water enters a steam turbine to do work so as to drive a second generator to generate electricity; the heat energy is utilized in a cascade way, and the cost is reduced.

9. The gas-steam combined cycle subsystem of the application further comprises: the heat regenerator is arranged between the gas compressor and the combustion chamber, one end of the heat regenerator is connected with the first heat exchanger, and the other end of the heat regenerator is connected with the phase change heat storage tank; by adopting the technical scheme, the gas after heat exchange of the first heat exchanger enters the heat regenerator to heat the air at the outlet of the hot press; the heat energy is utilized in a cascade way, and the cost is reduced.

10. The power grid peak shaving system provided by the application further comprises: the control center is connected with the solar photo-thermal power generation subsystem, the gas-steam combined circulation subsystem, the molten salt heat storage subsystem and the power grid; the control center is suitable for acquiring the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem, the power grid demand and the load of the gas-steam combined cycle subsystem and controlling the solar photo-thermal power generation subsystem, the gas-steam combined cycle subsystem and the molten salt heat storage and release subsystem to work cooperatively; by adopting the technical scheme, the control center uniformly coordinates and controls the relationship among the solar photo-thermal power generation subsystem, the gas-steam combined circulation subsystem, the molten salt heat storage subsystem and the power grid, so that the peak shaving capacity of the power grid is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a connection structure of a power grid peak shaving system according to an embodiment of the present invention;

fig. 2 is a schematic diagram illustrating the use of a phase change heat storage tank according to an embodiment of the present invention.

Reference numerals illustrate:

1. a first generator; 2. a compressor; 3. a regenerator; 4. a combustion chamber; 5. a turbine; 6. a first switch; 7. a first heat exchanger; 8. an electric heater; 9. a first valve; 10. a second valve; 11. a third valve; 12. a fourth valve; 13. a first molten salt tank; 14. a first molten salt pump; 15. a fifth valve; 16. a second switch; 17. a second molten salt tank; 18. a second molten salt pump; 19. a sixth valve; 20. a seventh valve; 21. sun is carried out; 22. a heliostat field; 23. a heat absorber; 24. an eighth valve; 25. a ninth valve; 26. a third molten salt pump; 27. a waste heat boiler; 28. a second heat exchanger; 29. a steam turbine; 30. a second generator; 31. a condenser; 32. a water pump; 33. a deaerator; 34. a phase change heat storage tank; 35. a fuel; 36. air; 37. a factory; 38. and (5) a user.

Detailed Description

The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

In addition, the technical features of the different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

One embodiment of the grid peaking system as shown in fig. 1-2, includes: the solar energy photo-thermal power generation subsystem, the turbo generator set, the fused salt heat storage subsystem and the electric heater 8 which are connected in sequence, the first power generator 1, the gas-steam combined cycle subsystem and the phase change heat storage tank 34 which are connected in sequence, the condenser 31, the water pump 32 and the deaerator 33 which are connected in sequence, and the control center.

As shown in fig. 1, the turbo generator set includes: and a turbine 29 and a second generator 30 are connected. The molten salt Chu Fangre subsystem includes: a first molten salt tank 13 (i.e., a high temperature molten salt tank), a second heat exchanger 28, and a second molten salt tank 17 (i.e., a low temperature molten salt tank). The first salt melting tank 13 is used for storing redundant heat energy in the photo-thermal power generation and combined cycle power generation processes, releasing heat when the power supply is insufficient, and filling the difference between the power generation system and the power grid requirement; specifically, the molten salt in the first molten salt tank 13 and the second molten salt tank 17 may be binary salt and/or ternary salt, etc. selected according to the actual working conditions. The fused salt Chu Fangre subsystem is connected with the solar photo-thermal power generation subsystem; the steam turbine generator unit is connected with the solar photo-thermal power generation subsystem and the molten salt heat storage and release subsystem, and the steam turbine generator unit is connected to a power grid. The power grid peak shaving system is provided with a first state that when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is larger than the power required by a power grid, the solar photo-thermal power generation subsystem stores part of heat in the fused salt Chu Fangre subsystem, and the solar photo-thermal power generation subsystem uses the other part of heat for the power generation of the turbo generator set; and a second state in which the solar photo-thermal power generation subsystem uses all heat for the steam turbine generator unit to generate power when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is equal to the power required by the power grid; and a third state in which the solar photo-thermal power generation subsystem uses heat for the turbo-generator set to generate power when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is smaller than the electric quantity required by the electric network, and the fused salt Chu Fangre subsystem uses heat for the turbo-generator set to generate power. And under the first state, the second state and the third state, the gas-steam combined cycle subsystem stops working.

The first generator 1 is connected with a gas-steam combined cycle subsystem, and the first generator 1 is connected to a power grid; the gas-steam combined circulation subsystem is connected with the steam turbine generator unit and the molten salt heat storage and release subsystem; the electric heater 8 is connected with the first generator 1, the molten salt heat storage and release subsystem and the steam turbine generator unit; specifically, the electric heater 8 is connected with the first generator 1 through the first switch 6, and the electric heater 8 is connected with the second generator 30 through the second switch 16; the electric heater 8 is connected with the second molten salt tank 17 through a third valve 11, a sixth valve 19 and a second molten salt pump 18 which are sequentially connected. The electric heater 8 is adapted to heat the molten salt in the molten salt Chu Fangre subsystem, i.e. to heat the molten salt with the electrical energy of the first generator 1 and the second generator 30. The power grid peak shaving system is in a fourth state that the gas-steam combined cycle subsystem drives the steam turbine generator unit to generate power when the power grid requirement is equal to the full-load power generation capacity of the gas-steam combined cycle subsystem; and a fifth state having a gas-steam combined cycle subsystem storing a portion of the heat in a molten salt Chu Fangre subsystem when the grid demand is equal to the low load power generation of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem utilizing another portion of the heat for steam turbine generator unit power generation; and when the power grid requirement is equal to zero load power generation of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem stores a part of heat in the fused salt Chu Fangre subsystem, the gas-steam combined cycle subsystem uses another part of heat for generating power by the turbo generator set, the first generator 1 and the turbo generator set supply power for the electric heater 8, and the electric heater 8 stores the heated fused salt to a sixth state of the fused salt heat storage and release subsystem; and the seventh state that when the power grid requirement is equal to the overload power generation capacity of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem drives the steam turbine generator unit to generate power, and the heat of the fused salt Chu Fangre subsystem is used for the steam turbine generator unit to generate power. In the fourth, fifth, sixth and seventh states, the photo-thermal power generation amount of the solar photo-thermal power generation subsystem is zero, and the gas-steam combined cycle subsystem drives the first power generator 1 to generate power.

As shown in fig. 1, the solar photo-thermal power generation subsystem includes: a heliostat field 22 and a heat sink 23; the heliostat field 22 is adapted to receive sunlight of the sun 21 and reflect to the heat sink 23; the heat absorber 23 is adapted to absorb sunlight reflected by the heliostat field 22 and convert it into heat energy to heat the molten salt to a high temperature state. The inlet of the first molten salt tank 13 is connected with the outlet of the heat absorber 23; specifically, a fourth valve 12, a third molten salt pump 26 and an eighth valve 24 are sequentially disposed on a pipeline connected between the inlet of the first molten salt tank 13 and the outlet of the heat absorber 23.

The second heat exchanger 28 (namely a molten salt-water heat exchanger) is connected with the outlet of the heat absorber 23, the outlet of the first molten salt tank 13 and the turbo generator set; specifically, the second heat exchanger 28 is connected to the outlet of the heat absorber 23 through a third molten salt pump 26 (i.e. a high-temperature molten salt pump) and an eighth valve 24; the second heat exchanger 28 is connected to the outlet of the first molten salt tank 13 via a first molten salt pump 14 (i.e., a high temperature molten salt pump) and a fifth valve 15. The second molten salt tank 17 is connected with the inlets of the second heat exchanger 28 and the heat absorber 23; specifically, the second molten salt tank 17 is connected to the inlet of the heat absorber 23 through a second molten salt pump 18, a sixth valve 19 and a ninth valve 25 which are sequentially connected. The heat absorber 23 is adapted to heat the molten salt fed from the second molten salt tank 17 and feed the heated molten salt to the first molten salt tank 13 or the second heat exchanger 28; the second heat exchanger 28 is adapted to exchange heat between molten salt and water, and to transfer the heated water to a turbo generator set for power generation, and to transfer the cooled molten salt to the heat absorber 23.

The gas-steam combined cycle subsystem includes: the compressor 2, the combustion chamber 4 and the turbine 5, the first heat exchanger 7 (i.e. molten salt-gas heat exchanger) and the regenerator 3, and the waste heat boiler 27 are connected in this order. The first heat exchanger 7 is connected with the turbine 5, the first molten salt tank 13 and the second molten salt tank 17; specifically, the first heat exchanger 7 is connected with the turbine 5 through a first valve 9, and the first heat exchanger 7 is connected with a second molten salt tank 17 through a second valve 10, a sixth valve 19 and a second molten salt pump 18 which are sequentially connected. The compressor 2 is adapted to introduce air 36; the combustion chamber 4 is adapted to introduce fuel 35 and to combust air 36 delivered by the compressor 2 with the fuel 35 to form a fuel gas; the turbine 5 is suitable for receiving the fuel gas transmitted by the combustion chamber 4 and driving the first generator 1 to rotate for generating electricity; the first heat exchanger 7 is adapted to receive the combustion gases of the turbine 5, exchange heat between the low temperature molten salt from the second molten salt tank 17 and the high temperature combustion gases from the turbine 5 and to deliver the heated molten salt to the first molten salt tank 13. The heat regenerator 3 is arranged between the compressor 2 and the combustion chamber 4, one end of the heat regenerator 3 is connected with the first heat exchanger 7, and the other end of the heat regenerator 3 is connected with the phase-change heat storage tank 34. The condenser 31 is connected to the steam turbine 29, and the deaerator 33 is connected to the second heat exchanger 28. One end of the waste heat boiler 27 is connected with the turbine 5 through a seventh valve 20, and the other end of the waste heat boiler 27 is connected with a phase-change heat storage tank 34; the deaerator 33 is also connected to a waste heat boiler 27, and the waste heat boiler 27 is also connected to a steam turbine 29. Specifically, the second heat exchanger 28 exchanges heat between the high-temperature molten salt from the first molten salt tank 13 and the low-temperature water from the deaerator 33. The air 36 compressed by the compressor 2 enters the heat regenerator 3 to exchange heat with the fuel gas after the heat exchange with the molten salt. Then, after being combusted with the fuel 35 in the combustion chamber 4, high-temperature and high-pressure fuel gas is formed and enters the turbine 5 to do work so as to drive the first generator 1 to generate electricity. After the turbine 5 works, high-temperature low-pressure gas is formed, one part of the gas enters a fused salt-gas heat exchanger to heat fused salt according to the system load and the power grid demand, and the other part of the gas enters a waste heat boiler 27 to heat water to generate superheated steam; the superheated steam enters the steam turbine 29 to do work, drives the second generator 30 to generate electricity, enters the condenser 31 to be condensed into water, is pressurized by the water pump 32, and enters the waste heat boiler 27 to carry out the next cycle.

The control center is connected with the solar photo-thermal power generation subsystem, the gas-steam combined circulation subsystem, the molten salt heat storage subsystem and the power grid; the control center is suitable for acquiring the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem, the power grid demand and the load of the gas-steam combined cycle subsystem, controlling the solar photo-thermal power generation subsystem, the gas-steam combined cycle subsystem and the molten salt heat storage and release subsystem to work cooperatively, and particularly controlling the states of the valve and the switch. Further, heat insulation materials are wrapped outside the pipeline for conveying molten salt, the first molten salt tank 13 and the second molten salt tank 17 so as to reduce heat dissipation loss; and the pipelines for conveying the molten salt are all sleeved pipes, namely the molten salt is arranged in the central pipe, and the outer interlayer is steam or fuel gas for preheating the molten salt so as to prevent the molten salt from being blocked after solidification in the pipe.

As shown in fig. 2, the phase change heat storage tank 34 is connected to the combined gas-steam cycle subsystem, and the phase change heat storage tank 34 is adapted to store a portion of the heat (i.e., the industrial waste heat) of the combined gas-steam cycle subsystem in the plant 37 in the fourth, fifth, sixth and seventh states to supply heat to the user 38. Specifically, the low-temperature fuel gas at the outlet of the waste heat boiler 27 and the outlet of the regenerator 3 is stored in the phase-change heat storage tank 34, and then transported to a residential area by a truck to supply heat to the user 38 for winter heating and domestic hot water. The phase-change heat storage tank 34 may have any one of a shell-and-tube type, a plate type and a packed bed type, and the packed phase-change material may be a low-temperature phase-change material (phase-change temperature is below 90 ℃) such as paraffin, myristic acid and hydrated salt.

The main working process of the power grid peak shaving system is briefly described as follows, and the main working process specifically comprises the following four conditions:

1. condition of sufficient solar energy: when the weather is good and the illumination intensity is high, the solar photo-thermal power generation subsystem is started when the photo-thermal power generation amount is larger than the electric quantity required by the power grid, the heat storage function of the fused salt Chu Fangre subsystem is started, the heat release function of the fused salt Chu Fangre subsystem is closed, the gas-steam combined cycle subsystem is stopped (namely, the operation is stopped), and the turbo generator set is started. The fourth valve 12, the sixth valve 19, the eighth valve 24 and the ninth valve 25 are opened, and the first valve 9, the second valve 10, the third valve 11, the fifth valve 15 and the seventh valve 20 are closed. Heliostat field 22 reflects light from sun 21 into heat absorber 23 for heating the molten salt. A third molten salt pump 26 (which is a high-temperature molten salt pump) is used for conveying a part of the heated molten salt to the first molten salt tank 13 for storage; the other part is conveyed to a second heat exchanger 28 to heat water into superheated steam, and then molten salt subjected to heat exchange and temperature reduction sequentially passes through a second molten salt tank 17, a second molten salt pump 18 (a low-temperature molten salt pump), a sixth valve 19 and a ninth valve 25, and enters the heat absorber 23 for the next cycle. After being heated by high-temperature molten salt in the second heat exchanger 28 to be superheated steam, the water enters the steam turbine 29 to do work so as to drive the second generator 30 to generate electricity. The exhaust gas after work is done enters a condenser 31 to be cooled into condensed water; pressurizing by a water pump 32 and entering a deaerator 33 to remove oxygen and other gases dissolved in water, so as to prevent or weaken corrosion of pipelines and equipment; and then re-enters the second heat exchanger 28 for the next cycle.

2. Less solar energy: when the weather is general and the illumination intensity is general, and the photo-thermal power generation amount is equal to the electric quantity required by the power grid, the solar photo-thermal power generation subsystem is started, the fused salt Chu Fangre subsystem is closed, the gas-steam combined cycle subsystem is stopped, and the turbo generator set is started. The sixth valve 19, the eighth valve 24 and the ninth valve 25 are opened, and the first valve 9, the second valve 10, the third valve 11, the fourth valve 12, the fifth valve 15 and the seventh valve 20 are closed. Heliostat field 22 reflects light from sun 21 into heat absorber 23 for heating the molten salt. All the heated molten salt is conveyed to a second heat exchanger 28 by a third molten salt pump 26, and water is heated into superheated steam; and then the molten salt subjected to heat exchange and temperature reduction sequentially passes through the second molten salt tank 17, the second molten salt pump 18, the sixth valve 19 and the ninth valve 25, and enters the heat absorber 23 for the next cycle. After being heated by high-temperature molten salt in the second heat exchanger 28 to be superheated steam, the water enters the steam turbine 29 to do work so as to drive the second generator 30 to generate electricity. The exhaust gas after work is done enters a condenser 31 to be cooled into condensed water; pressurizing by a water pump 32 and entering a deaerator 33 to remove oxygen and other gases dissolved in water, so as to prevent or weaken corrosion of pipelines and equipment; and then re-enters the second heat exchanger 28 for the next cycle.

3. Insufficient solar energy conditions: when the weather is worse and the illumination intensity is weaker, the solar photo-thermal power generation subsystem is started when the photo-thermal power generation amount is smaller than the electric quantity required by the power grid, the heat storage function of the fused salt Chu Fangre subsystem is closed, the heat release function of the fused salt Chu Fangre subsystem is started, the gas-steam combined cycle subsystem is stopped, and the turbo generator unit is started. The fifth valve 15, the sixth valve 19, the eighth valve 24 and the ninth valve 25 are opened, and the first valve 9, the second valve 10, the third valve 11, the fourth valve 12 and the seventh valve 20 are closed. Heliostat field 22 reflects light from sun 21 into heat absorber 23 for heating the molten salt. All the heated molten salt is conveyed to the second heat exchanger 28 by the third molten salt pump 26, the molten salt in the first molten salt tank 13 is conveyed to the second heat exchanger 28 by the first molten salt pump 14 (which is a high-temperature molten salt pump), water is heated to superheated steam, and then the molten salt subjected to heat exchange and temperature reduction sequentially passes through the second molten salt tank 17, the second molten salt pump 18, the sixth valve 19 and the ninth valve 25 and enters the heat absorber 23 for next circulation. The flow rate of the second molten salt pump 18 is the same as the flow rate of the third molten salt pump 26, and the molten salt in the first molten salt tank 13 is stored in the second molten salt tank 17 after heat release. After being heated by high-temperature molten salt in the second heat exchanger 28 to be superheated steam, the water enters the steam turbine 29 to do work so as to drive the second generator 30 to generate electricity. The exhaust gas after work is done enters a condenser 31 to be cooled into condensed water; pressurizing by a water pump 32 and entering a deaerator 33 to remove oxygen and other gases dissolved in water, so as to prevent or weaken corrosion of pipelines and equipment; and then re-enters the second heat exchanger 28 for the next cycle.

4. Solar energy loss condition: when the weather is overcast and rainy days or at night, the solar photo-thermal power generation subsystem is stopped, and the gas-steam combined circulation subsystem and the molten salt heat storage subsystem are coordinated to meet the power demand of the power grid. According to the power generation capacity and the power grid demand of the gas-steam combined cycle subsystem, the following situations are further classified:

(1) when the power grid requirement is equal to the full-load (100%) power generation capacity of the gas-steam combined cycle subsystem, the fused salt Chu Fangre subsystem is closed, and the gas-steam combined cycle subsystem runs at full load. The seventh valve 20 is opened and the first valve 9, the second valve 10, the third valve 11, the fourth valve 12, the fifth valve 15, the sixth valve 19, the eighth valve 24 and the ninth valve 25 are closed. After being compressed by the compressor 2, the air 36 is combusted with the fuel 35 in the combustion chamber 4 to generate high-temperature high-pressure gas, and the high-temperature high-pressure gas enters the turbine 5 to do work so as to drive the first generator 1 to generate electricity. The high-temperature low-pressure gas after the turbine 5 works is fed into the waste heat boiler 27 to heat water, the gas after the heat exchange is fed into the phase change heat storage tank 34 to store the residual heat, and then the gas is transported to a residential area by a truck to supply heat for users, as shown in fig. 2. After being heated into superheated steam by high-temperature fuel gas in the waste heat boiler 27, the water enters the steam turbine 29 to do work so as to drive the second generator 30 to generate electricity. The exhaust gas after work is done enters a condenser 31 to be cooled into condensed water; pressurizing by a water pump 32 and entering a deaerator 33 to remove oxygen and other gases dissolved in water, so as to prevent or weaken corrosion of pipelines and equipment; then, the mixture is fed into the waste heat boiler 27 again for the next cycle.

(2) When the power grid requirement is equal to the low-load (0% -100%) power generation of the gas-steam combined cycle subsystem, the heat storage function of the fused salt Chu Fangre subsystem is started, the heat release function of the fused salt Chu Fangre subsystem is closed, and the gas-steam combined cycle subsystem runs at full load. The first valve 9, the second valve 10, the sixth valve 19 and the seventh valve 20 are opened, and the third valve 11, the fourth valve 12, the fifth valve 15, the eighth valve 24 and the ninth valve 25 are closed. After being compressed by the compressor 2, the air 36 is combusted with the fuel 35 in the combustion chamber 4 to generate high-temperature high-pressure gas, and the high-temperature high-pressure gas enters the turbine 5 to do work so as to drive the first generator 1 to generate electricity. Part of the high-temperature low-pressure gas after the work of the turbine 5 is completed enters the first heat exchanger 7 to heat molten salt, then enters the regenerator 3 to heat air 36 at the outlet of the compressor 2, and then enters the phase change heat storage tank 34; the other part of the high-temperature low-pressure gas after the turbine 5 works is fed into the waste heat boiler 27 to heat water, the gas after the heat exchange is fed into the phase change heat storage tank 34 to store the residual heat, and then the gas is transported to a residential area by a truck to supply heat for users, as shown in fig. 2. The second molten salt pump 18 conveys the low-temperature molten salt in the second molten salt tank 17 to the first heat exchanger 7 through the sixth valve 19 and the second valve 10 to absorb heat, and then enters the first molten salt tank 13 for storage. After being heated into superheated steam by high-temperature fuel gas in the waste heat boiler 27, the water enters the steam turbine 29 to do work so as to drive the second generator 30 to generate electricity. The exhaust gas after the work is completed enters the condenser 31 and is cooled to be condensed water. Pressurizing by a water pump 32 and entering a deaerator 33 to remove oxygen and other gases dissolved in water, so as to prevent or weaken corrosion of pipelines and equipment; then, the mixture is fed into the waste heat boiler 27 again for the next cycle.

(3) When the power grid requirement is equal to zero load (0%) power generation of the gas-steam combined cycle subsystem, the heat storage function of the fused salt Chu Fangre subsystem is started, the heat release function of the fused salt Chu Fangre subsystem is closed, and the gas-steam combined cycle subsystem runs at full load. The first valve 9, the second valve 10, the third valve 11, the sixth valve 19 and the seventh valve 20 are opened, and the fourth valve 12, the fifth valve 15, the eighth valve 24 and the ninth valve 25 are closed. After being compressed by the compressor 2, the air 36 is combusted with the fuel 35 in the combustion chamber 4 to generate high-temperature high-pressure gas, and the high-temperature high-pressure gas enters the turbine 5 to do work so as to drive the first generator 1 to generate electricity. Part of the high-temperature low-pressure gas after the work done by the turbine 5 enters the first heat exchanger 7 to heat molten salt, then enters the regenerator 3 to heat the air 36 at the outlet of the compressor 2, and then enters the phase change heat storage tank 34. The other part of the high-temperature low-pressure gas after the turbine 5 works is fed into the waste heat boiler 27 to heat water, the gas after the heat exchange is fed into the phase change heat storage tank 34 to store the residual heat, and then the gas is transported to a residential area by a truck to supply heat for users, as shown in fig. 2. The first switch 6 and the second switch 16 are activated and the power generated by the first generator 1 and the second generator 30 is all transferred to the electric heater 8 for heating the molten salt. The second molten salt pump 18 conveys a part of the low-temperature molten salt in the second molten salt tank 17 to the first heat exchanger 7 through the sixth valve 19 and the second valve 10 to absorb heat, and the second molten salt pump 18 conveys the other part of the low-temperature molten salt in the second molten salt tank 17 to the electric heater 8 through the sixth valve 19 and the third valve 11 and then enters the first molten salt tank 13 for storage. After being heated into superheated steam by high-temperature fuel gas in the waste heat boiler 27, the water enters the steam turbine 29 to do work so as to drive the second generator 30 to generate electricity. The exhaust gas after the work is completed enters the condenser 31 and is cooled to be condensed water. Pressurizing by a water pump 32 and entering a deaerator 33 to remove oxygen and other gases dissolved in water, so as to prevent or weaken corrosion of pipelines and equipment; then, the mixture is fed into the waste heat boiler 27 again for the next cycle.

(4) When the power grid requirement is equal to the overload (more than 100%) generated energy of the gas-steam combined cycle subsystem, the heat storage function of the fused salt Chu Fangre subsystem is closed, the heat release function of the fused salt Chu Fangre subsystem is started, and the gas-steam combined cycle subsystem runs at full load. The fifth valve 15 and the seventh valve 20 are opened, and the first valve 9, the second valve 10, the third valve 11, the fourth valve 12, the sixth valve 19, the eighth valve 24 and the ninth valve 25 are closed. After being compressed by the compressor 2, the air 36 is combusted with the fuel 35 in the combustion chamber 4 to generate high-temperature high-pressure gas, and the high-temperature high-pressure gas enters the turbine 5 to do work so as to drive the first generator 1 to generate electricity. The high-temperature low-pressure gas after the turbine 5 works is fed into the waste heat boiler 27 to heat water, the gas after the heat exchange is fed into the phase change heat storage tank 34 to store the residual heat, and then the gas is transported to a residential area by a truck to supply heat for users, as shown in fig. 2. The molten salt in the first molten salt tank 13 is also fed to the second heat exchanger 28 by the first molten salt pump 14, and the water is heated to superheated steam. The molten salt in the first molten salt tank 13 is stored in the second molten salt tank 17 after being released. One part of water is heated by high-temperature molten salt in the second heat exchanger 28 to form first part of superheated steam, the other part of water is heated by high-temperature fuel gas in the waste heat boiler 27 to form second part of superheated steam, and the two parts of superheated steam enter the steam turbine 29 to do work so as to drive the second generator 30 to generate electricity. The exhaust gas after the work is completed enters the condenser 31 and is cooled to be condensed water. Pressurizing by a water pump 32 and entering a deaerator 33 to remove oxygen and other gases dissolved in water, so as to prevent or weaken corrosion of pipelines and equipment; then, the waste heat boiler 27 and the second heat exchanger 28 are re-entered for the next cycle.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.

Claims (10)

1. A power grid peak shaving system, comprising:

a solar photo-thermal power generation subsystem;

a gas-steam combined cycle subsystem;

the fused salt Chu Fangre subsystem is connected with the solar photo-thermal power generation subsystem;

the steam turbine generator unit is connected with the solar photo-thermal power generation subsystem and the molten salt heat storage and release subsystem, and is connected to a power grid;

the power grid peak shaving system is provided with a first state that when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is larger than the power required by a power grid, the solar photo-thermal power generation subsystem stores part of heat in the fused salt Chu Fangre subsystem, and the solar photo-thermal power generation subsystem uses the other part of heat for the power generation of the turbo generator set; and a second state in which the solar photo-thermal power generation subsystem uses all heat for the steam turbine generator unit to generate power when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is equal to the power required by the power grid; when the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is smaller than the electric quantity required by the electric network, the solar photo-thermal power generation subsystem uses heat for the steam turbine generator unit to generate power, and the fused salt Chu Fangre subsystem uses heat for a third state of the steam turbine generator unit to generate power;

And under the first state, the second state and the third state, the gas-steam combined cycle subsystem stops working.

2. The grid peaking system of claim 1, further comprising:

a first generator (1) connected with the gas-steam combined cycle subsystem, wherein the first generator (1) is connected to a power grid; the gas-steam combined circulation subsystem is connected with the steam turbine generator unit and the molten salt heat storage and release subsystem;

the electric heater (8) is connected with the first generator (1), the molten salt heat storage and release subsystem and the steam turbine generator unit; -the electric heater (8) is adapted to heat molten salt in a molten salt Chu Fangre subsystem;

the power grid peak shaving system is in a fourth state that the gas-steam combined cycle subsystem drives the steam turbine generator unit to generate power when the power grid requirement is equal to the full-load power generation capacity of the gas-steam combined cycle subsystem; and a fifth state having a gas-steam combined cycle subsystem storing a portion of the heat in a molten salt Chu Fangre subsystem when the grid demand is equal to the low load power generation of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem utilizing another portion of the heat for steam turbine generator unit power generation; and the gas-steam combined cycle subsystem stores a part of heat in the fused salt Chu Fangre subsystem when the power grid requirement is equal to zero load power generation of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem uses another part of heat for generating power by a turbo generator set, the first generator (1) and the turbo generator set supply power for an electric heater (8), and the electric heater (8) stores the heated fused salt to a sixth state of the fused salt heat storage and release subsystem; when the power grid demand is equal to the overload power generation amount of the gas-steam combined cycle subsystem, the gas-steam combined cycle subsystem drives the steam turbine generator unit to generate power, and the heat of the fused salt Chu Fangre subsystem is used for a seventh state of the steam turbine generator unit to generate power;

And in the fourth state, the fifth state, the sixth state and the seventh state, the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem is zero, and the gas-steam combined cycle subsystem drives the first power generator (1) to generate power.

3. The grid peaking system of claim 1 or 2, further comprising:

and the phase-change heat storage tank (34) is connected with the fuel gas-steam combined cycle subsystem, and the phase-change heat storage tank (34) is suitable for storing part of heat of the fuel gas-steam combined cycle subsystem in a fourth state, a fifth state, a sixth state and a seventh state so as to supply heat for a user (38).

4. A grid peaking system as claimed in claim 3, wherein the solar photo-thermal power generation subsystem comprises: a heliostat field (22) and a heat absorber (23);

the heliostat field (22) is adapted to receive sunlight of the sun (21) and reflect to the heat absorber (23); the heat absorber (23) is adapted to absorb sunlight reflected by the heliostat field (22) and convert it into thermal energy.

5. The grid peaking system of claim 4, wherein the molten salt Chu Fangre subsystem comprises:

the inlet of the first molten salt tank (13) is connected with the outlet of the heat absorber (23);

The second heat exchanger (28) is connected with the outlet of the heat absorber (23), the outlet of the first molten salt tank (13) and the steam turbine generator unit;

the second molten salt tank (17) is connected with the inlets of the second heat exchanger (28) and the heat absorber (23);

the heat absorber (23) is suitable for heating molten salt conveyed by the second molten salt tank (17) and conveying the heated molten salt to the first molten salt tank (13) or the second heat exchanger (28);

the second heat exchanger (28) is suitable for exchanging heat between molten salt and water, and conveying the heated water to a turbo generator set for power generation, and conveying the cooled molten salt to the heat absorber (23).

6. The grid peaking system of claim 5, wherein the gas-steam combined cycle subsystem comprises:

the compressor (2), the combustion chamber (4) and the turbine (5) are connected in sequence;

the first heat exchanger (7) is connected with the turbine (5), the first molten salt tank (13) and the second molten salt tank (17);

the compressor (2) is adapted to introduce air (36);

the combustion chamber (4) is suitable for introducing fuel (35) and combusting air (36) delivered by the compressor (2) with the fuel (35) to form fuel gas;

the turbine (5) is suitable for receiving the fuel gas transmitted by the combustion chamber (4) and driving the first generator (1) to rotate for power generation;

The first heat exchanger (7) is adapted to receive the gas of the turbine (5), exchange heat between the molten salt from the second molten salt tank (17) and the gas, and deliver the heated molten salt to the first molten salt tank (13).

7. The grid peaking system of claim 6, wherein the turbo generator set comprises: a turbine (29) and a second generator (30) which are connected to each other;

the grid peak shaving system further comprises: a condenser (31), a water pump (32) and a deaerator (33) which are connected in sequence;

the condenser (31) is connected with the steam turbine (29), and the deaerator (33) is connected with the second heat exchanger (28).

8. The grid peaking system of claim 7, wherein the gas-steam combined cycle subsystem further comprises:

one end of the waste heat boiler (27) is connected with the turbine (5), and the other end of the waste heat boiler (27) is connected with the phase-change heat storage tank (34); the deaerator (33) is also connected with a waste heat boiler (27), and the waste heat boiler (27) is also connected with a steam turbine (29).

9. The grid peaking system of claim 6, wherein the gas-steam combined cycle subsystem further comprises:

the heat regenerator (3) is arranged between the gas compressor (2) and the combustion chamber (4), one end of the heat regenerator (3) is connected with the first heat exchanger (7), and the other end of the heat regenerator (3) is connected with the phase-change heat storage tank (34).

10. The grid peaking system of claim 1 or 2, further comprising:

the control center is connected with the solar photo-thermal power generation subsystem, the gas-steam combined circulation subsystem, the molten salt heat storage subsystem and the power grid; the control center is suitable for acquiring the photo-thermal power generation capacity of the solar photo-thermal power generation subsystem, the power grid demand and the load of the gas-steam combined cycle subsystem, and controlling the solar photo-thermal power generation subsystem, the gas-steam combined cycle subsystem and the molten salt heat storage and release subsystem to work cooperatively.