Thermal power generating unit system integrated with heat pump energy storage, peak shaving and frequency modulation

Abstract

The embodiment of the present disclosure provides a kind of integrated heat pump energy storage peak shaving frequency modulation thermal power generating unit system, by coupling heat pump energy storage device driven by small steam turbine, when unit load reduction, increase small steam turbine extraction steam quantity, reduce large steam turbine flow, reduce unit output;Small steam turbine surplus output drives heat pump to run, converts mechanical energy into cold energy and heat energy storage;When unit load increase, utilize the high temperature heat of storage to heat high feedwater, dislodge high pressure extraction steam, simultaneously utilize the low temperature heat of storage to cool low pressure cylinder exhaust steam, reduce unit back pressure, to increase unit output.The mechanical energy and heat energy are converted to each other by coupling heat pump energy storage device, to realize unit deep peak shaving, fast peak shaving, frequency modulation and the like;Heat pump energy storage device hot end and cold end energy is fully stored and utilized, energy loss is less, and energy utilization efficiency is higher;Heat pump energy storage device and host coupling degree are weak, system is simple, and operation is flexible, with good safety and economy.

Description

TECHNICAL FIELD

[0001] The embodiment of the present disclosure belongs to the technical field of peak regulation and frequency modulation of thermal power plants, and particularly relates to a peak regulation and frequency modulation thermal power unit system integrated with heat pump energy storage. BACKGROUND

[0002] Wind power, photovoltaic power and other new energy power generation have the characteristics of near-zero carbon dioxide emission, and large-scale construction and grid connection of the two can replace a large amount of carbon emission intensity higher coal-fired power, greatly reducing carbon dioxide emissions in the power industry. However, wind power, photovoltaic power and other new energy power generation are seriously dependent on weather conditions, and have the characteristics of instability, volatility and intermittency. Large-scale grid connection of the two will cause power grid fluctuations, affecting the safe and stable operation of the power grid. Therefore, flexible power generation technologies such as thermal power are needed to regulate power output, shave peaks and fill valleys, smooth power output, avoid power grid fluctuations, and maintain the safe and stable operation of the power grid. Therefore, the role of thermal power has changed from basic power supply to flexible regulation power supply.

[0003] When the thermal power unit is deeply regulated at low load, it faces problems such as low-load stable combustion of the boiler, safety of the water power cycle, too low inlet flue gas temperature of the low-load desuperheating device of the boiler, and life loss of the unit during long-term low-load operation.

[0004] In view of the above problems, it is necessary to provide a thermal power unit system integrated with heat pump energy storage for peak regulation and frequency modulation, which is reasonable in design and effective in solving the above problems. SUMMARY

[0005] The embodiment of the present disclosure aims to at least solve one of the technical problems existing in the prior art, and provides a thermal power unit system integrated with heat pump energy storage for peak regulation and frequency modulation.

[0006] The embodiment of the present disclosure provides a thermal power unit system integrated with heat pump energy storage for peak regulation and frequency modulation, comprising 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 comprises 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 operated 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 heat energy in the high-temperature hot tank.

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

[0012] Therefore, the inlet of the low-temperature turbine is connected with the outlet of the cooler, the outlet of the low-temperature turbine is connected with the cold side inlet of the low-temperature heat exchanger, and the hot side outlet of the low-temperature heat exchanger is connected with the inlet of the low-temperature cold tank to store the low-temperature thermal 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 connected with the cold side inlet of the regenerator, and the cold side outlet of the regenerator is connected with the inlet of the high-temperature compressor.

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

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

[0016] When the unit is in load increase, the hot side inlet of the auxiliary high-pressure heater is connected with the outlet of the high-temperature hot tank, and the hot side outlet of the auxiliary high-pressure heater is connected with the inlet of the high-temperature cold tank.

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

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

[0019] Optionally, the power generation device further comprises a feedwater pump and a high-pressure heater;

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

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

[0022] Optionally, the small steam turbine is connected with the feedwater pump to drive the feedwater pump.

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

[0024] When the unit is in load increase, the cold side inlet of the auxiliary circulating water cooler is connected with the outlet of the low-temperature cold tank, and the cold side outlet of the auxiliary circulating water cooler is connected with the inlet of the low-temperature hot tank.

[0025] Optionally, the power generation unit may also include 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] The peak-shaving and frequency-regulating thermal power unit system with integrated heat pump energy storage according to this embodiment of the invention, through a heat pump energy storage device driven by a small steam turbine, increases the steam extraction rate of the small steam turbine and reduces the flow rate of the large steam turbine during the unit's load reduction process, thereby further reducing the unit's output. Meanwhile, the surplus output of the small steam turbine drives the heat pump to operate, converting mechanical energy into cold and heat energy for storage. During the unit's load increase process, the stored high-temperature heat is used to heat the high-pressure feedwater and displace the high-pressure steam extraction, while the stored low-temperature heat is used to cool the low-pressure cylinder exhaust steam.

[0030] This system reduces the unit's back pressure, thereby increasing its output. It achieves the mutual conversion of mechanical and thermal energy through a coupled heat pump energy storage device, enabling deep peak shaving, rapid peak load adjustment, and frequency regulation. The heat pump energy storage device fully stores and utilizes energy at both the hot and cold ends, resulting in minimal energy loss and high energy efficiency. The coupling between the heat pump energy storage device and the main unit is relatively weak, making the system simple, flexible in operation, and offering good safety and economy. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a thermal power unit system with integrated heat pump energy storage for peak shaving and frequency regulation, as described in one embodiment of this disclosure. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions of the embodiments of this disclosure, the embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0033] like Figure 1 As shown, this disclosure provides a thermal power unit system with integrated heat pump energy storage for peak shaving and frequency regulation, including a power generation unit and a heat pump energy storage unit.

[0034] like Figure 1As shown, the power generation device includes a boiler 1, a high-pressure cylinder 2, a medium-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 hot tank 21, a low-temperature cold tank 22, a high-temperature cold tank 23, a high-temperature hot tank 24, and an auxiliary high-pressure heater 25.

[0036] The boiler 1 is connected to the high-pressure cylinder 2, the high-pressure cylinder 2 is connected to the boiler 1, the boiler 1 is connected to the medium-pressure cylinder 3, the medium-pressure cylinder 3 is connected to the low-pressure cylinder 4, the low-pressure cylinder 4 is connected to the condenser 5, the condenser 5 is connected to the condensate pump 6, the condensate pump 6 is connected to the low-pressure heater 7, the low-pressure heater 7 is connected to the deaerator 8, the deaerator 8 is connected to the feed water pump 9, the feed water pump 9 is connected to the high-pressure heater 10, and the high-pressure heater 10 is connected to the boiler 1.

[0037] The high-pressure cylinder 2 is connected to the high-pressure heater 10, the medium-pressure cylinder 3 is connected to the deaerator 8, the low-pressure cylinder 4 is connected to the low-pressure heater 7, the medium-pressure cylinder 3 is connected to the small steam turbine 11, the small steam turbine 11 is connected to the condenser 5, the cooling tower 12 is connected to the auxiliary circulating water cooler 13, the auxiliary circulating water cooler 13 is connected to the circulating water pump 14, the circulating water pump 14 is connected to the condenser 5, and the condenser 5 is connected to 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, and 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 hot 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 tank 22, the outlet of the low-temperature cold tank 22 is connected to the inlet of the cold side of the auxiliary circulating water cooler 13, and the outlet of the cold side of the auxiliary circulating water cooler 13 is connected to the inlet of the low-temperature hot tank 21; the outlet of the high-temperature cold 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 hot tank 24, the outlet of the high-temperature hot tank 24 is connected to the inlet of the hot side of the auxiliary high-pressure heater 25, and the outlet of the hot side of the auxiliary high-pressure heater 25 is connected to the inlet of the high-temperature cold 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, and 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 the embodiment, the small 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 medium of the low-temperature hot tank 21 and the low-temperature cold tank 22 is water. The heat storage medium of the high-temperature cold tank 23 and the high-temperature hot tank 24 is molten salt or heat conducting oil.

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

[0041] Under normal circumstances, when the unit load is low load operation, the load of the feed water pump 9 is also reduced, and the steam extraction amount of the small turbine 11 driving the feed water pump 9 is reduced, and the load is reduced to match the load of the feed water pump 9.

[0042] When the unit is running at low load, the small turbine 11 is connected to the medium-pressure cylinder 3, so that the small turbine 11 can maintain a large amount of steam extraction, thereby reducing the flow of the medium-pressure cylinder 3 and the low-pressure cylinder 4 after the steam extraction port, and further reducing the unit output to achieve deep peak shaving. The surplus output of the small turbine 11 drives the high-temperature compressor 15 of the heat pump energy storage device. The high-temperature compressor 15 compresses the heat pump circulating working medium to a high-temperature state, and then releases heat in the high-temperature heat exchanger 16 to the high-temperature heat storage medium from the high-temperature cold tank 23. The high-temperature heat storage medium is stored in the high-temperature hot tank 24. The circulating working medium is further cooled in the cooler 18 after being heated by the cold side working medium in the regenerator 17, and then enters the low-temperature turbine 19 to expand and do work. A part of the working capacity of the low-temperature turbine 19 is recovered to drive the high-temperature compressor 15. The exhaust steam of the low-temperature turbine 19 becomes low-pressure and low-temperature working medium, which is then cooled in the low-temperature heat exchanger 20 to the low-temperature heat storage medium from the low-temperature hot tank 21. 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 mechanical energy output by the small turbine 11 is converted into heat energy and stored, and the unit load is further reduced to achieve further deep peak shaving.

[0043] When the unit is running at low load, the small turbine 11 is connected to the medium-pressure cylinder 3, so that the small turbine 11 can maintain a large amount of steam extraction, thereby reducing the flow of the medium-pressure cylinder 3 and the low-pressure cylinder 4 after the steam extraction port, and further reducing the unit output to achieve deep peak shaving. The surplus output of the small turbine 11 drives the high-temperature compressor 15 of the heat pump energy storage device. The high-temperature compressor 15 compresses the heat pump circulating working medium to a high-temperature state, and then releases heat in the high-temperature heat exchanger 16 to the high-temperature heat storage medium from the high-temperature cold tank 23. The high-temperature heat storage medium is stored in the high-temperature hot tank 24. The circulating working medium is further cooled in the cooler 18 after being heated by the cold side working medium in the regenerator 17, and then enters the low-temperature turbine 19 to expand and do work. A part of the working capacity of the low-temperature turbine 19 is recovered to drive the high-temperature compressor 15. The exhaust steam of the low-temperature turbine 19 becomes low-pressure and low-temperature working medium, which is then cooled in the low-temperature heat exchanger 20 to the low-temperature heat storage medium from the low-temperature hot tank 21. 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 mechanical energy output by the small turbine 11 is converted into heat energy and stored, and the unit load is further reduced to achieve further deep peak shaving.

[0044] The peak shaving and frequency modulation thermal power unit system integrated with the heat pump energy storage device of the embodiment of the present disclosure couples the heat pump energy storage device driven by the small turbine. During the unit load reduction process, the small turbine steam extraction amount is increased, and the large turbine flow is reduced, thereby further reducing the unit output. The surplus output of the small turbine drives the heat pump to run, and the mechanical energy is converted into cold energy and heat energy for storage. During the unit load increase process, the stored high-temperature heat is used to heat the high-pressure heater feedwater, and the stored low-temperature heat is used to cool the low-pressure cylinder exhaust steam, thereby reducing the unit back pressure and increasing the unit output. The system couples the heat pump energy storage device to realize the mutual conversion of mechanical energy and heat energy, thereby achieving the functions of deep peak shaving, rapid peak shaving, frequency modulation, etc. The heat end and cold end energy of the heat pump energy storage device is fully stored and utilized, the energy loss is small, and the energy utilization efficiency is high. The heat pump energy storage device and the main unit are weakly coupled, the system is simple, the operation is flexible, and the system has good safety and economy.

[0045] It can be understood that the above implementation is only an exemplary implementation adopted for illustrating the principles of the embodiments of the present disclosure, however, the embodiments of the present disclosure are not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and principle of the embodiments of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the embodiments of the present disclosure.

Claims

1. A thermal power generating unit system integrated with heat pump energy storage, peak shaving and frequency modulation, characterized in that, The power generation device and the heat pump energy storage device are provided. 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, and further comprises a condenser, a circulating water pump and a cooling tower. The heat pump energy storage device comprises 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 a low load: The inlet of the small steam turbine is connected with the outlet of the medium-pressure cylinder, and the outlet of the small steam turbine is connected with the steam-side inlet of the condenser, wherein the surplus output of the small steam turbine drives the high-temperature compressor of the heat pump energy storage device. The hot-side inlet of the high-temperature heat exchanger is connected with the outlet of the high-temperature compressor, and the cold-side outlet of the high-temperature heat exchanger is connected with the inlet of the high-temperature hot tank, so as to store the high-temperature heat storage medium in the high-temperature hot tank in the form of heat energy. The hot-side inlet of the regenerator is connected with the hot-side outlet of the high-temperature heat exchanger, and the hot-side outlet of the regenerator is connected with the inlet of the cooler. The inlet of the low-temperature turbine is connected with the outlet of the cooler, the outlet of the low-temperature turbine is connected with the cold-side inlet of the low-temperature heat exchanger, and the hot-side outlet of the low-temperature heat exchanger is connected with the inlet of the low-temperature cold tank, so as to store the low-temperature heat storage medium in the low-temperature cold tank in the form of cold energy; wherein, The heat pump energy storage device further comprises a high-temperature cold tank and an auxiliary high-pressure heater; wherein, When the unit is running at a high load, the hot-side inlet of the auxiliary high-pressure heater is connected with the outlet of the high-temperature hot tank, the hot-side outlet of the auxiliary high-pressure heater is connected with the inlet of the high-temperature cold tank, the outlet of the high-temperature cold tank is connected with the cold-side inlet of the high-temperature heat exchanger, and the cold-side outlet of the auxiliary high-pressure heater is connected with the feedwater inlet of the boiler. The heat pump energy storage device further comprises a low-temperature hot tank and an auxiliary circulating water cooler. When the unit is running at a high load, the cold-side inlet of the auxiliary circulating water cooler is connected with the outlet of the low-temperature cold tank, and the cold-side outlet of the auxiliary circulating water cooler is connected with the inlet of the low-temperature hot tank. The outlet of the cooling tower is connected with the hot-side inlet of the auxiliary circulating water cooler, the hot-side outlet of the auxiliary circulating water cooler is connected with the inlet of the circulating water pump, the outlet of the circulating water pump is connected with the water-side inlet of the condenser, and the water-side outlet of the condenser is connected with the inlet of the cooling tower.

2. The system of claim 1, wherein, The cold-side outlet of the low-temperature heat exchanger is connected with the cold-side inlet of the regenerator, and the cold-side outlet of the regenerator is connected with the inlet of the high-temperature compressor.

3. The system of claim 1, wherein, The low-pressure turbine is connected with the high-temperature compressor to drive the high-temperature compressor.

4. The system according to any one of claims 1 to 3, characterized in that, The power generation device further comprises a feedwater pump and a high-pressure heater. The inlet of the feedwater pump is connected with the outlet of the medium-pressure cylinder, and the outlet of the feedwater pump is connected with the cold-side inlet of the auxiliary high-pressure heater and the water-side inlet of the high-pressure heater respectively. The water-side outlet of the high-pressure heater is connected with the feedwater inlet of the boiler.

5. The system of claim 4, wherein, The small steam turbine is connected with the feedwater pump to drive the feedwater pump.

6. The system of any one of claims 1 to 3, wherein, The power generation device further comprises a condensate pump. The inlet of the condensate pump is connected with the outlet of the condenser, and the outlet of the condensate pump is connected with the water side inlet of the low-pressure heater.

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