Thermal power generating unit system integrating heat pump energy storage and capable of regulating peak and frequency

Abstract

According to the peak and frequency modulation thermal power generating unit system integrating heat pump energy storage, by coupling the heat pump energy storage device driven by the small steam turbine, when the load of the unit is reduced, the steam extraction amount of the small steam turbine is increased, the flow of the large steam turbine is reduced, and the output of the unit is reduced; surplus output of the small steam turbine drives the heat pump to operate, and mechanical energy is converted into cold energy and heat energy to be stored; when the load of the unit is increased, the stored high-temperature heat is used for heating the high-pressure heater feed water and squeezing the high-pressure extracted steam, and meanwhile, the stored low-temperature heat is used for cooling the low-pressure cylinder exhaust steam and reducing the back pressure of the unit, so that the output of the unit is increased. Mutual conversion between mechanical energy and heat energy is achieved through the coupling heat pump energy storage device, and therefore the effects of deep peak regulation, rapid peak jacking, frequency modulation and the like of the unit are achieved; energy at the hot end and the cold end of the heat pump energy storage device is fully stored and utilized, energy loss is small, and the energy utilization efficiency is high; the coupling degree of the heat pump energy storage device and the main machine is weak, the system is simple, operation is flexible, and good safety and economical efficiency are achieved.

Description

Technical Field

[0001] The disclosed embodiments belong to the technical field of peak-shaving and frequency-regulation of thermal power plants, and specifically relate to a peak-shaving and frequency-regulating thermal power unit system with integrated heat pump energy storage. Background Art

[0002] New energy power generation such as wind power and photovoltaic power has the characteristics of near-zero carbon dioxide emissions. The large-scale construction and grid connection of the two can replace a large amount of coal-fired electricity with high carbon emission intensity, and significantly reduce carbon dioxide emissions in the power industry. However, new energy power such as wind power and photovoltaic power is heavily dependent on meteorological conditions, and the output is unstable, with volatility and intermittent characteristics. The large-scale grid connection of the two will cause grid fluctuations and affect the safe and stable operation of the grid. Therefore, flexible power generation technologies such as thermal power are needed to adjust the output of power sources, reduce peaks and fill valleys, smooth power output, avoid grid fluctuations, and maintain the safe and stable operation of the grid. Therefore, the role of thermal power has changed from a basic power source that bears base load to a flexible regulating power source.

[0003] When thermal power units are performing deep peak regulation at low load, they face problems such as stable combustion of the boiler at low load, safety issues of hydrodynamic circulation, low inlet flue gas temperature of the boiler's low load de-energizing device, and loss of unit life due to long-term low load operation.

[0004] In view of the above problems, it is necessary to propose a thermal power unit system with integrated heat pump energy storage and peak and frequency regulation that is reasonably designed and effectively solves the above problems. Summary of the invention

[0005] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a peak-shaving and frequency-modulating thermal power generation unit system with integrated heat pump energy storage.

[0006] The embodiment of the present disclosure provides a peak-shaving and frequency-modulating thermal power generation unit system with integrated heat pump energy storage, including a power generation device and a heat pump energy storage device;

[0007] The power generation device comprises a boiler, a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder and a small steam turbine connected in sequence;

[0008] The heat pump energy storage device includes a high-temperature compressor, a high-temperature heat exchanger, a regenerator, a cooler, a low-temperature turbine, a low-temperature heat exchanger, a low-temperature cold tank and a high-temperature hot tank; wherein, when the unit is running at low load:

[0009] The inlet of the small steam turbine is connected to the outlet of the medium pressure cylinder, and the outlet of the small steam turbine is connected to the inlet of the high temperature compressor;

[0010] The hot side inlet of the high temperature heat exchanger is connected to the outlet of the high temperature compressor, and the cold side outlet of the high temperature heat exchanger is connected to the inlet of the high temperature hot tank, so as to store the high temperature heat storage medium in the form of thermal energy in the high temperature hot tank;

[0011] The hot-side inlet of the regenerator is connected to the hot-side outlet of the high-temperature heat exchanger, and the hot-side outlet of the regenerator is connected to the inlet of the cooler;

[0012] Therefore, the inlet of the low-temperature turbine is connected to the outlet of the cooler, the outlet of the low-temperature turbine is connected to the cold-side inlet of the low-temperature heat exchanger, and the hot-side outlet of the low-temperature heat exchanger is connected to the inlet of the low-temperature cold tank to store the low-temperature heat storage medium in the form of cold energy in the low-temperature cold tank.

[0013] Optionally, the cold-side outlet of the low-temperature heat exchanger is communicated with the cold-side inlet of the regenerator, and the cold-side outlet of the regenerator is connected to the inlet of the high-temperature compressor.

[0014] Optionally, the low-pressure turbine is connected to the high-temperature compressor to drive the high-temperature compressor.

[0015] Optionally, the heat pump energy storage device further includes a high-temperature cold tank and an auxiliary high-pressure heater; wherein,

[0016] When the unit is increasing load, the hot-side inlet of the auxiliary high-pressure heater is connected to the outlet of the high-temperature heat tank, and the hot-side outlet of the auxiliary high-pressure heater is connected to the inlet of the high-temperature cold tank;

[0017] The outlet of the high-temperature cold tank is connected to the cold-side inlet of the high-temperature heat exchanger.

[0018] Optionally, the cold-side outlet of the auxiliary high-pressure heater is communicated with the feed water inlet of the boiler.

[0019] Optionally, the power generation device further includes a feed water pump and a high-pressure heater;

[0020] The inlet of the feed water pump is connected to the outlet of the intermediate-pressure cylinder, and the outlet of the feed water pump is respectively connected to the cold-side inlet of the auxiliary high-pressure heater and the water-side inlet of the high-pressure heater;

[0021] The water-side outlet of the high-pressure heater is communicated with the feed water inlet of the boiler.

[0022] Optionally, the small steam turbine is connected to the feed water pump to drive the feed water pump.

[0023] Optionally, the heat pump energy storage device further includes a low-temperature heat tank and an auxiliary circulating water cooler;

[0024] When the unit is increasing load, the cold-side inlet of the auxiliary circulating water cooler is connected to the outlet of the low-temperature cold tank, and the cold-side outlet of the auxiliary circulating water cooler is connected to the inlet of the low-temperature heat tank.

[0025] Optionally, the power generation device further includes a condenser, a circulating water pump, and a cooling tower;

[0026] The outlet of the cooling tower is connected to the hot side inlet of the auxiliary circulating water cooler, the hot side outlet of the auxiliary circulating water cooler is connected to the inlet of the circulating water pump, the outlet of the circulating water pump is connected to the water side inlet of the condenser, and the water side outlet of the condenser is connected to the inlet of the cooling tower.

[0027] Optionally, the power generation device further includes a condensate pump;

[0028] The inlet of the condensate pump is connected to the outlet of the condenser, and the outlet of the condensate pump is connected to the inlet of the small steam turbine.

[0029] In the peak shaving and frequency modulation thermal power unit system integrated with a heat pump energy storage according to an embodiment of the present disclosure, by coupling a heat pump energy storage device driven by a small steam turbine, during the load reduction process of the unit, the extraction steam volume of the small steam turbine is increased, and the flow rate of the large steam turbine is reduced, thereby further reducing the output of the unit; while the surplus output of the small steam turbine drives the heat pump to operate, converting mechanical energy into cold energy and heat energy for storage; during the load increase process of the unit, the stored high-temperature heat is used to heat the feed water of the high-pressure heater, displacing the high-pressure extraction steam, and at the same time, the stored low-temperature heat is used to cool the exhaust steam of the low-pressure cylinder,

[0030] reducing the back pressure of the unit, thereby increasing the output of the unit. This system realizes the mutual conversion of mechanical energy and heat energy by coupling the heat pump energy storage device, thereby realizing functions such as deep peak shaving, rapid peak topping, and frequency modulation of the unit; the energy at the hot end and cold end of the heat pump energy storage device is fully stored and utilized, with less energy loss and higher energy utilization efficiency; the coupling degree between the heat pump energy storage device and the main engine is weak, the system is simple, the operation is flexible, and it has good safety and economy. Description of the Drawings

[0031] Figure 1 It is a schematic structural diagram of a peak shaving and frequency modulation thermal power unit system integrated with a heat pump energy storage according to an embodiment of the present disclosure. Detailed Embodiments

[0032] To enable those skilled in the art to better understand the technical solutions of the embodiments of the present disclosure, the following further describes the embodiments of the present disclosure in detail with reference to the drawings and specific embodiments.

[0033] As Figure 1 shown, an embodiment of the present disclosure provides a peak shaving and frequency modulation thermal power unit system integrated with a heat pump energy storage, including a power generation device and a heat pump energy storage device.

[0034] As Figure 1As shown in the figure, the power generation device includes a boiler 1, a high-pressure cylinder 2, an intermediate-pressure cylinder 3, a low-pressure cylinder 4, a condenser 5, a condensate pump 6, a low-pressure heater 7, a deaerator 8, a feed water pump 9, a high-pressure heater 10, a small steam turbine 11, a cooling tower 12, an auxiliary circulating water cooler 13, and a circulating water pump 14.

[0035] The heat pump energy storage device includes a high-temperature compressor 15, a high-temperature heat exchanger 16, a regenerator 17, a cooler 18, a low-temperature turbine 19, a low-temperature heat exchanger 20, a low-temperature heat storage tank 21, a low-temperature cold storage tank 22, a high-temperature cold storage tank 23, a high-temperature heat storage tank 24, and an auxiliary high-pressure heater 25.

[0036] Among them, the main steam outlet of the boiler 1 is connected to the inlet of the high-pressure cylinder 2, the exhaust steam outlet of the high-pressure cylinder 2 is connected to the reheat steam inlet of the boiler 1, the reheat steam outlet of the boiler 1 is connected to the inlet of the intermediate-pressure cylinder 3, the exhaust steam outlet of the intermediate-pressure cylinder 3 is connected to the inlet of the low-pressure cylinder 4, the exhaust steam outlet of the low-pressure cylinder 4 is connected to the hot side inlet of the condenser 5, the hot side outlet of the condenser 5 is connected to the inlet of the condensate pump 6, the outlet of the condensate pump 6 is connected to the water side inlet of the low-pressure heater 7, the water side outlet of the low-pressure heater 7 is connected to the water side inlet of the deaerator 8, the water side outlet of the deaerator 8 is connected to the inlet of the feed water pump 9, and the outlet of the feed water pump 9 is connected to the water side inlet of the high-pressure heater 10, and the water side outlet of the high-pressure heater 10 is connected to the feed water inlet of the boiler 1.

[0037] The extraction port of the high-pressure cylinder 2 is connected to the steam side inlet of the high-pressure heater 10; the extraction port of the intermediate-pressure cylinder 3 is connected to the steam side inlet of the deaerator 8; the extraction port of the low-pressure cylinder 4 is connected to the steam side inlet of the low-pressure heater 7; the extraction port of the intermediate-pressure cylinder 3 is connected to the inlet of the small steam turbine 11; the outlet of the small steam turbine 1 is connected to the steam side inlet of the condenser 5; the outlet of the cooling tower 12 is connected to the hot side inlet of the auxiliary circulating water cooler 13, the hot side outlet of the auxiliary circulating water cooler 13 is connected to the inlet of the circulating water pump 14, the outlet of the circulating water pump 14 is connected to the water side inlet of the condenser 5, and the water side outlet of the condenser 5 is connected to the inlet of the cooling tower 12.

[0038] The outlet of the high-temperature compressor 15 is connected to the inlet of the hot side of the high-temperature heat exchanger 16. The outlet of the hot side of the high-temperature heat exchanger 16 is connected to the inlet of the hot side of the regenerator 17. The outlet of the hot side of the regenerator 17 is connected to the inlet of the cooler 18. The outlet of the cooler 18 is connected to the inlet of the low-temperature turbine 19. The outlet of the low-temperature turbine 19 is connected to the inlet of the cold side of the low-temperature heat exchanger 20. The outlet of the cold side of the low-temperature heat exchanger 20 is connected to the inlet of the cold side of the regenerator 17. The outlet of the cold side of the regenerator 17 is connected to the inlet of the high-temperature compressor 15. The outlet of the low-temperature heat storage tank 21 is connected to the inlet of the hot side of the low-temperature heat exchanger 20. The outlet of the hot side of the low-temperature heat exchanger 20 is connected to the inlet of the low-temperature cold storage tank 22. The outlet of the low-temperature cold storage tank 22 is connected to the inlet of the cold side of the auxiliary circulating water cooler 13. The outlet of the cold side of the auxiliary circulating water cooler 13 is connected to the inlet of the low-temperature heat storage tank 21. The outlet of the high-temperature cold storage tank 23 is connected to the inlet of the cold side of the high-temperature heat exchanger 16. The outlet of the cold side of the high-temperature heat exchanger 16 is connected to the inlet of the high-temperature heat storage tank 24. The outlet of the high-temperature heat storage tank 24 is connected to the inlet of the hot side of the auxiliary high-pressure heater 25. The outlet of the hot side of the auxiliary high-pressure heater 25 is connected to the inlet of the high-temperature cold storage tank 23. The inlet of the cold side of the auxiliary high-pressure heater 25 is connected to the outlet of the feed water pump 9. The outlet of the cold side of the auxiliary high-pressure heater 25 is connected to the inlet of the feed water of the boiler 1.

[0039] In addition, in this embodiment, the small steam turbine 11 drives the feed water pump 9 and the high-temperature compressor 15. The low-temperature turbine 19 drives the high-temperature compressor 15. The heat storage media in the low-temperature heat storage tank 21 and the low-temperature cold storage tank 22 are water. The heat storage media in the high-temperature cold storage tank 23 and the high-temperature heat storage tank 24 are molten salt or heat-conducting oil.

[0040] Specifically, the process of peak shaving and frequency modulation of the thermal power unit system with integrated heat pump energy storage according to the embodiments of the present disclosure can be as follows:

[0041] Under normal circumstances, when the unit load is operating at a low load, the load of the feed water pump 9 also decreases accordingly. At the same time, the extraction steam volume of the small steam turbine 11 that drives the feed water pump 9 decreases, and the load decreases to match the load of the feed water pump 9.

[0042] When the unit operates at low load, by connecting the small steam turbine 11 to the intermediate pressure cylinder 3, a relatively large extraction steam volume of the small steam turbine 11 is maintained to reduce the flow rates of the intermediate pressure cylinder 3 and the low pressure cylinder 4 after the extraction steam port, thereby further reducing the unit output and achieving deep peak shaving. The surplus output of the small steam turbine 11 drives the high-temperature compressor 15 of the heat pump energy storage device. After the high-temperature compressor 15 compresses the heat pump circulating working medium to a high-temperature state, it releases heat to the high-temperature heat storage medium from the high-temperature cold tank 23 in the high-temperature heat exchanger 16, and the high-temperature heat storage medium is stored in the high-temperature heat tank 24. After the circulating working medium heats the cold-side working medium in the regenerator 17, it is further cooled in the cooler 18, and then enters the low-temperature turbine 19 to expand and do work. A part of the working medium work capacity is recovered by using the low-temperature turbine 19 to drive the high-temperature compressor 15. The exhaust steam of the low-temperature turbine 19 becomes the low-pressure and low-temperature working medium, and then cools the low-temperature heat storage medium from the low-temperature heat tank 21 in the low-temperature heat exchanger 20. The low-temperature heat storage medium is stored in the low-temperature cold tank 22 in the form of cold energy. Through the above process, the conversion and storage of the mechanical energy output by the small steam turbine 11 into heat energy are realized, and further the unit load is reduced to achieve further deep peak shaving.

[0043] When the unit operates at increasing load, on the one hand, the high-temperature heat storage medium stored in the high-temperature heat tank 24 enters the auxiliary high-pressure heater 25 to heat part of the feed water, thereby reducing the feed water flow rate of the high-pressure heater 10. The exhaust steam part of the extraction steam returns to the steam turbine to do work, increasing the unit output. On the other hand, the low-temperature heat storage medium stored in the low-temperature cold tank 22 enters the auxiliary circulating water cooler 13 to further cool the circulating water. Further, the circulating water cools the exhaust steam of the low-pressure cylinder 4 in the condenser 5, reducing the unit back pressure and increasing the unit output. The above load-increasing process has a relatively fast response speed and also has a frequency modulation function.

[0044] A peak shaving and frequency modulation thermal power unit system integrated with a heat pump energy storage according to an embodiment of the present disclosure, by coupling a heat pump energy storage device driven by a small steam turbine, during the unit load reduction process, the extraction steam volume of the small steam turbine is increased, and the flow rate of the large steam turbine is reduced, thereby further reducing the unit output; while the surplus output of the small steam turbine drives the heat pump to operate, converting mechanical energy into cold energy and heat energy for storage; during the unit load increasing process, the stored high-temperature heat is used to heat the high-pressure heater feed water, displacing the high-pressure extraction steam, and at the same time, the stored low-temperature heat is used to cool the exhaust steam of the low-pressure cylinder, reducing the unit back pressure, thereby increasing the unit output. This system realizes the mutual conversion of mechanical energy and heat energy by coupling the heat pump energy storage device, thereby realizing functions such as deep peak shaving, rapid peak reaching, and frequency modulation of the unit; the energy at the hot end and cold end of the heat pump energy storage device is fully stored and utilized, with less energy loss and higher energy utilization efficiency; the coupling degree between the heat pump energy storage device and the main engine is weak, the system is simple, the operation is flexible, and it has good safety and economy.

[0045] It is understandable that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the embodiments of the present disclosure. However, the embodiments of the present disclosure are not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the embodiments of the present disclosure, and these modifications and improvements are also regarded as the protection scope of the embodiments of the present disclosure.

Claims

1. A thermal power generation system with integrated heat pump energy storage and peak load regulation, characterized in that: It includes a power generation device and a heat pump energy storage device; The power generation device comprises a boiler, a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder and a small steam turbine connected in sequence; The heat pump energy storage device includes a high-temperature compressor, a high-temperature heat exchanger, a regenerator, a cooler, a low-temperature turbine, a low-temperature heat exchanger, a low-temperature cold tank and a high-temperature hot tank; wherein, when the unit is running at low load: The inlet of the small steam turbine is connected to the outlet of the medium pressure cylinder, and the outlet of the small steam turbine is connected to the inlet of the high temperature compressor; The hot side inlet of the high temperature heat exchanger is connected to the outlet of the high temperature compressor, and the cold side outlet of the high temperature heat exchanger is connected to the inlet of the high temperature hot tank, so as to store the high temperature heat storage medium in the form of thermal energy in the high temperature hot tank; The hot side inlet of the regenerator is connected to the hot side outlet of the high temperature heat exchanger, and the hot side outlet of the regenerator is connected to the inlet of the cooler; Therefore, the inlet of the low-temperature turbine is connected to the outlet of the cooler, the outlet of the low-temperature turbine is connected to the cold side inlet of the low-temperature heat exchanger, and the hot side outlet of the low-temperature heat exchanger is connected to the inlet of the low-temperature cold tank, so as to store the low-temperature heat storage medium in the form of cold energy in the low-temperature cold tank.

2. The system according to claim 1, characterized in that The cold side outlet of the low temperature heat exchanger is connected to the cold side inlet of the regenerator, and the cold side outlet of the regenerator is connected to the inlet of the high temperature compressor.

3. The system according to claim 1, characterized in that The low-pressure turbine is connected to the high-temperature compressor to drive the high-temperature compressor.

4. The system according to claim 1, characterized in that The heat pump energy storage device also includes a high-temperature cold tank and an auxiliary high-pressure heater; wherein, When the unit is loaded, the hot side inlet of the auxiliary high-pressure heater is connected to the outlet of the high-temperature hot tank, and the hot side outlet of the auxiliary high-pressure heater is connected to the inlet of the high-temperature cold tank; The outlet of the high-temperature cold tank is connected to the cold side inlet of the high-temperature heat exchanger.

5. The system according to claim 4, characterized in that The cold side outlet of the auxiliary high pressure heater is communicated with the feed water inlet of the boiler.

6. The system according to claim 4, characterized in that The power generation device also includes a feed water pump and a high-pressure heater; The inlet of the water supply pump is connected to the outlet of the intermediate pressure cylinder, and the outlet of the water supply pump is respectively connected to the cold side inlet of the auxiliary high-pressure heater and the water side inlet of the high-pressure heater; The water side outlet of the high pressure heater is communicated with the feed water inlet of the boiler.

7. The system according to claim 6, characterized in that The small steam turbine is connected to the feed water pump and is used to drive the feed water pump.

8. The system according to any one of claims 1 to 7, characterized in that: The heat pump energy storage device also includes a low-temperature heat tank and an auxiliary circulating water cooler; When the unit increases load, the cold side inlet of the auxiliary circulating water cooler is connected to the outlet of the low-temperature cold tank, and the cold side outlet of the auxiliary circulating water cooler is connected to the inlet of the low-temperature hot tank.

9. The system according to claim 8, characterized in that The power generation device also includes a condenser, a circulating water pump and a cooling tower; The outlet of the cooling tower is connected to the hot side inlet of the auxiliary circulating water cooler, the hot side outlet of the auxiliary circulating water cooler is connected to the inlet of the circulating water pump, the outlet of the circulating water pump is connected to the water side inlet of the condenser, and the water side outlet of the condenser is connected to the inlet of the cooling tower.

10. The system according to claim 9, characterized in that The power generation device also includes a condensate pump; The inlet of the condensate pump is connected to the outlet of the condenser, and the outlet of the condensate pump is connected to the inlet of the small steam turbine.

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