A coal-fired power generation system with integrated pump heat storage and operation method

Abstract

The present invention relates to the field of power generation technology, and specifically to a coal-fired power generation system with integrated pump heat storage and an operating method. A coal-fired power generation system with integrated pump heat storage comprises: a boiler, a steam turbine, a first generator, a heat pump compressor, a heat storage device, a heat pump turbine and at least one extraction cooler connected in sequence, wherein the extraction cooler is also connected to the steam turbine; a heat engine compressor, a boiler, a heat storage device, a heat engine turbine, a feed water heat recovery component and a cooler connected in sequence, wherein the heat engine compressor is also connected to a second generator; a first valve and a second valve, which are respectively arranged between the heat storage device and the heat pump turbine and between the cooler and the heat engine compressor. The present invention provides a coal-fired power generation system with integrated pump heat storage and an operating method that can effectively utilize energy and reduce heat energy waste.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation, and in particular to a coal-fired power generation system with integrated pump heat storage and an operation method thereof. Background Art

[0002] Coal-fired power generation plays a vital role in ensuring energy security and promoting the adoption of renewable energy. The "dual carbon" goals place urgent demands on the coal-fired power generation industry for higher efficiency and greater flexibility. However, in coal-fired power generation units, excess extraction steam heat is wasted, resulting in low energy utilization. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the coal-fired power generation system in the prior art in which heat energy is wasted and energy utilization rate is low, thereby providing a coal-fired power generation system and operation method with integrated pump heat storage that can effectively utilize energy and reduce heat energy waste.

[0004] In order to solve the above technical problems, the present invention provides a coal-fired power generation system with integrated pump heat storage, comprising:

[0005] A boiler, a steam turbine, a first generator, a heat pump compressor, a heat storage device, a heat pump turbine and at least one extraction steam cooler connected in sequence, wherein the extraction steam cooler is also connected to the steam turbine;

[0006] A heat engine compressor, a boiler, a heat storage device, a heat engine turbine, a feed water heat recovery component and a cooler connected in sequence, wherein the heat engine compressor is also connected to a second generator;

[0007] The first valve and the second valve are respectively arranged between the heat storage device and the heat pump turbine and between the cooler and the heat engine compressor. When the first valve is opened and the second valve is closed, the first generator drives the heat pump compressor to compress the heat pump working fluid, stores the heat in the heat storage device, and then enters the heat pump turbine to perform work, and then exchanges heat with the extraction cooler; when the first valve is closed and the second valve is opened, the working fluid at the outlet of the heat engine compressor exchanges heat with the boiler and the heat storage device in turn, enters the heat engine turbine to perform work, and then enters the feed water heat recovery component for heat exchange, and enters the heat engine compressor through the cooler. At this time, the second generator generates electricity.

[0008] Optionally, the steam turbine includes a high-pressure cylinder, an intermediate-pressure cylinder and a low-pressure cylinder connected in sequence, the high-pressure cylinder and the intermediate-pressure cylinder are both connected to the boiler, and the low-pressure cylinder is also connected to the first generator. At least one of the extraction steam coolers includes a high-pressure extraction steam cooler connected to the high-pressure cylinder and an intermediate-pressure extraction steam cooler connected to the intermediate-pressure cylinder. The high-pressure extraction steam cooler is also connected to the heat pump compressor, and the intermediate-pressure extraction steam cooler is also connected to the heat pump turbine.

[0009] Optionally, the feed water heat recovery component includes a high-pressure heater, a deaerator and a low-pressure heater which are connected in sequence, the high-pressure heater is connected to the heat engine turbine and the high-pressure cylinder, the medium-pressure cylinder is also connected to the high-pressure heater and the deaerator, and the low-pressure heater is connected to the low-pressure cylinder.

[0010] Optionally, a condenser is further provided between the low-pressure cylinder and the low-pressure heater.

[0011] Optionally, the inlet pressure of the heat engine compressor and the heat pump compressor are both 7.5-8.5 MPa, the outlet pressure is both 20-23 MPa, and the inlet temperature of the heat engine compressor is 32-40°C.

[0012] Optionally, a heat exchanger is provided in the boiler, the outlet of the heat engine compressor is connected to the heat exchanger, and the outlet of the heat exchanger is connected to a heat storage device.

[0013] Optionally, an air preheater is provided in the flue of the boiler at a position corresponding to the heat exchanger, the inlet of the air preheater is connected to cold air, and the outlet is connected to the boiler.

[0014] Optionally, a baffle is provided between the air preheater and the heat exchanger.

[0015] Optionally, the second generator is further connected to a power station auxiliary machine.

[0016] Also provided is an operating method of a coal-fired power generation system, comprising:

[0017] When the system is de-loaded or operating at low load, the first valve is opened and the second valve is closed. The first generator drives the heat pump compressor to compress the heat pump working fluid, stores the heat in the heat storage device, and then enters the heat pump turbine to perform work, and then exchanges heat with the extraction cooler; when the system is loaded or operating at high load, the first valve is closed and the second valve is opened. The working fluid at the outlet of the heat engine compressor exchanges heat with the boiler and the heat storage device in turn, enters the heat engine turbine to perform work, and then enters the feed water heat recovery component for heat exchange, and enters the heat engine compressor through the cooler. At this time, the second generator generates electricity.

[0018] The technical solution of the present invention has the following advantages:

[0019] 1. The coal-fired power generation system with integrated pump heat energy storage provided by the present invention, when the system reduces load or operates at low load, the first valve is opened and the second valve is closed, the first generator drives the heat pump compressor to compress the heat pump working fluid, stores the heat in the heat storage device, and then enters the heat pump turbine to perform work, and then exchanges heat with the extraction steam cooler, thereby using excess electricity to drive the heat pump cycle, and "pumps" the excess extraction steam heat energy to higher-grade storage; when the system increases load or operates at high load, the first valve is closed and the second valve is opened, the working fluid at the outlet of the heat engine compressor exchanges heat with the boiler and the heat storage device in turn, enters the heat engine turbine to perform work, and then enters the feed water heat recovery component for heat exchange, and enters the heat engine compressor through the cooler, at which time the second generator generates electricity; at the same time, the carbon dioxide working fluid at the outlet of the heat engine turbine replaces part of the turbine extraction steam to heat the feed water, thereby reducing steam extraction and achieving rapid load increase.

[0020] 2. The coal-fired power generation system with integrated pump heat storage provided by the present invention is equipped with an air preheater and a bypass flue at the tail of the boiler, and a heat exchanger is arranged to recover the waste heat in the tail flue, thereby achieving energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 Schematic diagram of the coal-fired power generation system with integrated pump heat storage provided by the present invention.

[0023] Description of reference numerals:

[0024] 1. Boiler; 2. Air preheater; 3. Baffle; 4. Heat exchanger; 5. High-pressure cylinder; 6. Medium-pressure cylinder; 7. Low-pressure cylinder; 8. First generator; 9. High-pressure extraction steam cooler; 10. Medium-pressure extraction steam cooler; 11. Heat pump compressor; 12. Heat pump turbine; 13. Heat storage device; 14. Heat engine turbine; 15. Heat engine compressor; 16. Second generator; 17. First valve; 18. Cooler; 19. Feedwater heat recovery assembly; 20. Second valve; 21. High-pressure heater; 22. Deaerator; 23. Low-pressure heater; 24. Condenser. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] like Figure 1 A specific embodiment of the coal-fired power generation system with integrated pump heat storage shown includes a boiler 1, a steam turbine, a first generator 8, a heat pump compressor 11, a heat storage device 13, a first valve 17, a heat pump turbine 12 and at least one extraction steam cooler connected in sequence, and the extraction steam cooler is also connected to the steam turbine.

[0028] The outlet of boiler 1 is equipped with a flue, which houses an SCR denitrification device. Below the SCR denitrification device is a baffle 3, forming a bypass flue between the baffle 3 and the corresponding sidewall of the flue. The bypass flue houses a heat exchanger 4. An air preheater 2 is installed in the flue of boiler 1 at a position corresponding to the heat exchanger 4. The air preheater 2 and heat exchanger 4 are located on either side of the baffle 3. The inlet of the air preheater 2 is connected to the cold air, and the outlet is connected to the boiler.

[0029] The steam turbine includes a high-pressure cylinder 5, an intermediate-pressure cylinder 6, and a low-pressure cylinder 7, which are coaxially connected in sequence. The high-pressure cylinder 5 and the intermediate-pressure cylinder 6 are both connected to the boiler 1. Steam generated by the boiler 1 is input through the inlet of the high-pressure cylinder 5. Steam output by the high-pressure cylinder 5 is then transferred back to the boiler 1. Reheated steam in the boiler 1 enters the intermediate-pressure cylinder 6 and the low-pressure cylinder 7 in sequence through pipelines. The low-pressure cylinder 7 is also connected to a first generator 8.

[0030] At least one of the extraction steam coolers includes a high-pressure extraction steam cooler 9 connected to the high-pressure cylinder 5 and a medium-pressure extraction steam cooler 10 connected to the medium-pressure cylinder 6. The high-pressure extraction steam cooler 9 is also connected to the heat pump compressor 11, and the medium-pressure extraction steam cooler 10 is also connected to the heat pump turbine 12.

[0031] Connected in sequence are a heat engine compressor 15, boiler 1, heat storage device 13, heat engine turbine 14, feedwater heat recovery assembly 19, and cooler 18. A second valve 20 is provided between cooler 18 and heat engine compressor 15. Heat engine compressor 15 is also connected to a second generator 16, which is in turn connected to power plant auxiliary equipment. The inlet pressure of heat engine compressor 15 and heat pump compressor 11 are both 7.5-8.5 MPa, and the outlet pressure is both 20-23 MPa. The inlet temperature of heat engine compressor 15 is 32-40°C.

[0032] The feed water heat recovery component 19 includes a high-pressure heater 21, a deaerator 22, a low-pressure heater 23 and a condenser 24 which are connected in sequence. The high-pressure heater 21 is connected to the heat engine turbine 14 and the high-pressure cylinder 5. The medium-pressure cylinder 6 is also connected to the high-pressure heater 21 and the deaerator 22. The low-pressure heater 23 is connected to the low-pressure cylinder 7 through the condenser 24.

[0033] When the first valve 17 is opened and the second valve 20 is closed, the first generator 8 drives the heat pump compressor 11 to compress the heat pump working fluid, stores the heat in the heat storage device 13, and then enters the heat pump turbine 12 to perform work and then exchanges heat with the extraction steam cooler; when the first valve 17 is closed and the second valve 20 is opened, the working fluid at the outlet of the heat engine compressor 15 exchanges heat with the boiler 1 and the heat storage device 13 in turn, enters the heat engine turbine 14 to perform work, and then enters the feed water heat recovery component 19 for heat exchange, and enters the heat engine compressor 15 through the cooler 18. At this time, the second generator 16 generates electricity.

[0034] Preferably, the working fluid of the heat pump cycle and the heat engine cycle is supercritical carbon dioxide.

[0035] A method for operating a coal-fired power generation system, comprising:

[0036] The steam at the outlet of boiler 1 enters the high-pressure cylinder 5 of the steam turbine to perform work. The steam at the outlet of high-pressure cylinder 5 enters the boiler 1 for reheating, and then enters the medium-pressure cylinder 6 and the low-pressure cylinder 7 in turn to continue expanding and performing work; the steam at the outlet of low-pressure cylinder 7 enters the condenser 24 in the feed water heat recovery component 19 for cooling.

[0037] When the system is unloaded or operating at low load, the first valve 17 is opened, the second valve 20 is closed, and the opening of the damper 3 is reduced. The first generator 8 drives the heat pump compressor 11 to compress the heat pump working fluid, stores the heat in the heat storage device 13, and then enters the heat pump turbine 12 to perform work and then exchanges heat with the extraction cooler; when the system is unloaded or operating at high load, the first valve 17 is closed, the second valve 20 is opened, and the opening of the damper 3 is increased. The working fluid at the outlet of the heat engine compressor 15 exchanges heat with the boiler 1 and the heat storage device 13 in turn, enters the heat engine turbine 14 to perform work, and then enters the feed water heat recovery component 19 for heat exchange, and enters the heat engine compressor 15 through the cooler 18. At this time, the second generator 16 generates electricity.

[0038] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A coal-fired power generation system with integrated pump heat storage, characterized in that: include: A boiler (1), a steam turbine, a first generator (8), a heat pump compressor (11), a heat storage device (13), a heat pump turbine (12), and at least one extraction cooler connected in sequence, wherein the extraction cooler is also connected to the steam turbine; A heat engine compressor (15), a boiler (1), a heat storage device (13), a heat engine turbine (14), a feed water heat recovery component (19), and a cooler (18) connected in sequence, wherein the heat engine compressor (15) is further connected to a second generator (16); The first valve (17) and the second valve (20) are respectively arranged between the heat storage device (13) and the heat pump turbine (12) and between the cooler (18) and the heat engine compressor (15). When the first valve (17) is opened and the second valve (20) is closed, the first generator (8) drives the heat pump compressor (11) to compress the heat pump working fluid, stores the heat in the heat storage device (13), and then enters the heat pump turbine (12) to perform work and then exchanges heat with the extraction cooler. When the first valve (17) is closed and the second valve (20) is opened, the working fluid at the outlet of the heat engine compressor (15) exchanges heat with the boiler (1) and the heat storage device (13) in sequence, enters the heat engine turbine (14) to perform work, and then enters the feed water heat recovery component (19) for heat exchange, and then enters the heat engine compressor (15) through the cooler (18). At this time, the second generator (16) generates electricity.

2. The coal-fired power generation system with integrated pump heat storage according to claim 1 is characterized in that: The steam turbine comprises a high-pressure cylinder (5), an intermediate-pressure cylinder (6) and a low-pressure cylinder (7) connected in sequence, wherein the high-pressure cylinder (5) and the intermediate-pressure cylinder (6) are both connected to the boiler (1), and the low-pressure cylinder (7) is also connected to the first generator (8). At least one of the extraction steam coolers comprises a high-pressure extraction steam cooler (9) connected to the high-pressure cylinder (5) and an intermediate-pressure extraction steam cooler (10) connected to the intermediate-pressure cylinder (6), the high-pressure extraction steam cooler (9) is also connected to a heat pump compressor (11), and the intermediate-pressure extraction steam cooler (10) is also connected to a heat pump turbine (12).

3. The coal-fired power generation system with integrated pump heat storage according to claim 2 is characterized in that: The feed water heat recovery component (19) includes a high-pressure heater (21), a deaerator (22) and a low-pressure heater (23) which are connected in sequence. The high-pressure heater (21) is connected to the heat engine turbine (14) and the high-pressure cylinder (5). The medium-pressure cylinder (6) is also connected to the high-pressure heater (21) and the deaerator (22). The low-pressure heater (23) is connected to the low-pressure cylinder (7).

4. The coal-fired power generation system with integrated pump heat storage according to claim 3 is characterized in that: A condenser (24) is also provided between the low-pressure cylinder (7) and the low-pressure heater (23).

5. The coal-fired power generation system with integrated pump heat storage according to any one of claims 1 to 4, characterized in that: The inlet pressures of the heat engine compressor (15) and the heat pump compressor (11) are both 7.5-8.5 MPa, the outlet pressures are both 20-23 MPa, and the inlet temperature of the heat engine compressor (15) is 32-40°C.

6. The coal-fired power generation system with integrated pump heat storage according to any one of claims 1 to 4, characterized in that: A heat exchanger (4) is provided in the boiler (1), an outlet of the heat engine compressor (15) is connected to the heat exchanger (4), and an outlet of the heat exchanger (4) is connected to a heat storage device (13).

7. The coal-fired power generation system with integrated pump heat storage according to claim 6, characterized in that: An air preheater (2) is provided in the flue of the boiler (1) at a position corresponding to the heat exchanger (4); the inlet of the air preheater (2) is connected to cold air, and the outlet is connected to the boiler.

8. The coal-fired power generation system with integrated pump heat storage according to claim 7 is characterized in that: A baffle (3) is provided between the air preheater (2) and the heat exchanger (4).

9. The coal-fired power generation system with integrated pump heat storage according to any one of claims 1 to 4, characterized in that: The second generator (16) is also connected to a power station auxiliary machine.

10. An operating method of a coal-fired power generation system with integrated pump heat storage according to any one of claims 1 to 9, characterized in that: include: When the system is operating at a reduced load or low load, the first valve (17) is opened and the second valve (20) is closed. The first generator (8) drives the heat pump compressor (11) to compress the heat pump working fluid, stores the heat in the heat storage device (13), and then enters the heat pump turbine (12) to perform work and then exchanges heat with the extraction cooler. When the system is operating at a high load or high load, the first valve (17) is closed and the second valve (20) is opened. The working fluid at the outlet of the heat engine compressor (15) exchanges heat with the boiler (1) and the heat storage device (13) in sequence, enters the heat engine turbine (14) to perform work, and then enters the feed water heat recovery component (19) for heat exchange, and then enters the heat engine compressor (15) through the cooler (18). At this time, the second generator (16) generates electricity.

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