Compressed air energy storage-based deep peak shaving system for coal power unit

Abstract

The utility model relates to the technical field of thermal power generation and compressed air energy storage, in particular to a coal power unit deep peak shaving system based on compressed air energy storage, which comprises a main engine steam turbine respectively communicated with a gradient utilization steam turbine and a feed pump steam turbine through steam extraction drive. A driving shaft of the gradient utilization steam turbine is connected with an air compressor, an air outlet of the air compressor is sequentially communicated with an air storage device used for storing compressed air and an expansion machine using the compressed air to do work through a pipeline, and the expansion machine is connected with a water feeding pump steam turbine through a driving shaft provided with a clutch. The compressed air energy storage equipment is additionally arranged, part of steam is extracted from the main engine steam turbine, and the abundant power generation and heat supply capacity of the unit is stored through the compressed air energy storage equipment in the deep peak regulation period. And meanwhile, the stored energy is returned to the thermodynamic system in the non-deep peak regulation period.

Description

Technical Field

[0001] The utility model relates to the technical field of thermal power generation and compressed air energy storage, and in particular to a deep peak regulation system of a coal-fired power unit based on compressed air energy storage. Background Art

[0002] In recent years, China's energy has adhered to the development direction of clean, low-carbon, safe and efficient, vigorously developed wind power, solar energy and other clean energy power generation, and the pace of energy structure adjustment has been accelerating. However, wind and solar power generation are characterized by randomness, intermittency, and rapid changes. With the increase in the proportion of new energy power generation and the overcapacity of traditional coal-fired power generation, the difficulty of peak regulation of the power grid has been aggravated. Some regions have seriously abandoned wind and solar power, which has put forward new requirements for improving the flexibility of existing thermal power units and the deep peak regulation capability.

[0003] At present, most of the coal-fired power units in the Sanbei region are heating units. During the heating season, the peak-shaving capacity of thermal power units is limited under the heat-to-electricity mode. The lack of peak-shaving capacity seriously restricts the consumption of clean energy and affects the realization of the dual carbon goals. Utility Model Content

[0004] In order to solve at least one of the above technical problems, the utility model proposes a deep peak-shaving system for coal-fired power units based on compressed air energy storage. By setting up an air compressor and a gas storage device, during the peak-shaving period, the air compressor is driven by a steam turbine to compress the air into the gas storage device to store the surplus power generation and heating capacity of the unit during the deep peak-shaving period. During the non-peak-shaving period, the compressed air in the gas storage device is released to enter the expander to do work, and the feedwater pump steam turbine is driven to work in a superimposed manner, thereby realizing the time transfer of energy, and at the same time reducing the amount of steam extracted from the main engine steam turbine by the feedwater pump steam turbine, improving the overall output of the main engine steam turbine, and solving the problem of limited peak-shaving capacity of thermal power units in the heat-fixed power mode during the heating season.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A deep peak-shaving system for coal-fired power units based on compressed air energy storage, comprising a main engine steam turbine, wherein the main engine steam turbine is connected to a step utilization steam turbine and a feed water pump steam turbine respectively through steam extraction drive, the drive shaft of the step utilization steam turbine is connected to an air compressor, the air compressor outlet is connected to an air storage device for storing compressed air and an expander that uses compressed gas to do work in sequence through a pipeline, and the expander is connected to the feed water pump steam turbine through a drive shaft provided with a clutch.

[0007] Preferably, a heating system is further included, and the step utilization steam turbine, the air compressor and the expander are respectively connected to the heating system through pipelines.

[0008] Preferably, valves are provided between the main engine steam turbine and the step utilization steam turbine, between the main engine steam turbine and the feed water pump steam turbine, between the air compressor and the expander, and between the step utilization steam turbine and the heating system.

[0009] Preferably, the clutch is a 3S clutch.

[0010] Preferably, the gas storage device is a metal container or an artificial chamber.

[0011] Preferably, the air compressor is a turbo compressor.

[0012] Preferably, it also includes a feed water pump for driving the feed water pump turbine to work.

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] 1. The utility model is provided with an air compressor and an air storage device. During the peak-shaving period, the air compressor is driven by the steam turbine in stages to compress the air into the air storage device, thereby storing the surplus power generation and heating capacity of the unit during the deep peak-shaving period. During the non-peak-shaving period, the compressed air in the air storage device is released to enter the expander to do work, and the feedwater pump steam turbine is driven to work in a superimposed manner, thereby realizing the time transfer of energy, reducing the amount of steam extracted from the main engine steam turbine by the feedwater pump steam turbine, improving the overall output of the main engine steam turbine, and achieving the effect of thermal and electrical decoupling.

[0015] 2. The utility model uses the heat generated by the exhaust steam of the steam turbine, the heat generated by the air compressor during the compression of the air, and the waste heat after the air expansion of the expander to heat the hot network water in a step-by-step manner through the heat supply system recovery step. It fully releases the heat stored in the multi-stage heat storage equipment and can provide hot network water supply that meets the needs of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a deep peak regulation system of coal-fired power units based on compressed air energy storage;

[0017] In the figure: 1. Main engine steam turbine; 2. Cascade utilization steam turbine; 3. Air compressor; 4. Air storage device; 5. Expander; 6. 3S clutch; 7. Feed water pump steam turbine; 8. Feed water pump; 9. Heating system. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention.

[0019] Please refer to Figure 1 As shown, a deep peak-shaving system for coal-fired power units based on compressed air energy storage includes a main engine steam turbine 1, which is driven by extraction steam and connected to a step utilization steam turbine 2 and a feed water pump steam turbine 7 respectively, the drive shaft of the step utilization steam turbine 2 is connected to an air compressor 3, the air outlet of the air compressor 3 is sequentially connected to an air storage device 4 for storing compressed air and an expander 5 for doing work using compressed gas through pipelines, and the expander 5 is connected to the feed water pump steam turbine 7 through a drive shaft provided with a clutch.

[0020] This embodiment is provided with an air compressor 3 and an air storage device 4. During the peak-shaving period, the air compressor 3 is driven by the steam turbine 2 in a stepwise manner to compress the air into the air storage device 4, so as to store the surplus power generation and heating capacity of the unit during the deep peak-shaving period. During the non-peak-shaving period, the compressed air in the air storage device 4 is released to enter the expander 5 to perform work, and the feedwater pump steam turbine 7 is driven to work in a superimposed manner, so as to realize the time transfer of energy, and at the same time reduce the steam extraction amount of the feedwater pump steam turbine 7 from the main engine steam turbine 1, thereby improving the overall output of the main engine steam turbine 1 and achieving the effect of thermal-electric decoupling.

[0021] It should be noted that in the prior art, the above-mentioned cascade utilization turbine 2 and feedwater pump turbine 7 are driven by the extraction steam of the main engine turbine 1. The difference between this application and the prior art is that a compressed air energy storage device is newly added to extract part of the steam from the main engine turbine 1, and the compressed air energy storage device is used to store the surplus power generation and heating capacity of the unit during the deep peak-shaving period. At the same time, the stored energy is returned to the thermal system during the non-deep peak-shaving period.

[0022] It is understandable that the gas storage device 4 may be a metal container or an artificial chamber. The air compressor 3 may be a turbo compressor or other types of compressors. This application does not limit this.

[0023] In one embodiment, the clutch is a 3S clutch 6. It is understandable that the compressed air in the energy storage device enters the expander 5 to perform work, driving the expander 5 to rotate. When the speed of the expander 5 is lower than that of the feedwater pump turbine 7, the 3S clutch 6 is disconnected, and the connection between the expander 5 and the feedwater pump turbine 7 is cut off. When the speed of the expander 5 is higher than that of the feedwater pump turbine 7, the 3S clutch 6 is started, so that the expander 5 and the feedwater pump turbine 7 are in a connected state. At this time, the expander 5 can apply a certain driving force to the feedwater pump turbine 7.

[0024] It should be noted that, generally speaking, the feedwater pump steam turbine 7 is driven by the water flow output by the feedwater pump 8 connected thereto or by extracting a portion of steam from the main engine steam turbine 1. In this embodiment, the energy of the compressed air during the deep peak regulation period is converted into a portion of the driving force of the feedwater pump steam turbine 7 through the expander 5, which can appropriately reduce the steam extraction amount of the main engine steam turbine 1, thereby improving the overall output of the main engine steam turbine 1.

[0025] In order to further improve the utilization rate of energy, in a certain embodiment, a heating system 9 is further included, and the cascade utilization steam turbine 2, air compressor 3 and expander 5 are respectively connected to the heating system 9 through pipelines.

[0026] Specifically, the steam extracted from the main steam turbine 1 still has a certain temperature and pressure after doing work in the cascade utilization steam turbine 2. This part of the steam can be transported to the heating system 9 to continue to release heat; the air compressor 3 will generate a large amount of compression heat when performing compression work, and this part of the heat can enter the heating system 9 through the heat exchange device; the air after the expander 5 does work also has a certain temperature and pressure. By connecting it to the heating system 9, the heat in the air can be recovered.

[0027] It is understandable that the heat storage and release time is reasonably determined according to the peak-shaving demand of the power grid, and then the capacity of the steam turbine 2, air compressor 3, gas storage device 4, and expander 5 are determined in cascade utilization, so as to achieve a reasonable capacity for steam extraction energy storage and peak regulation.

[0028] In a certain embodiment, in order to facilitate the control of the opening and closing of the pipeline, valves are provided between the main engine steam turbine 1 and the cascade utilization steam turbine 2, between the main engine steam turbine 1 and the feed water pump steam turbine 7, between the air compressor 3 and the expander 5, and between the cascade utilization steam turbine 2 and the heating system 9.

[0029] The utility model is provided with an air compressor 3 and an air storage device 4. During the peak-shaving period, the steam turbine 2 is used in stages to drive the air compressor 3 to compress the air into the air storage device 4, thereby storing the abundant power generation and heating capacity of the unit during the deep peak-shaving period. During the non-peak-shaving period, the compressed air in the air storage device 4 is released to enter the expander 5 to perform work, and the feedwater pump steam turbine 7 is driven to work in a superimposed manner, thereby realizing the time transfer of energy, and at the same time reducing the amount of steam extracted from the main engine steam turbine 1 by the feedwater pump steam turbine 7, thereby increasing the overall output of the main engine steam turbine 1 and achieving the effect of thermal-electric decoupling.

[0030] The above is a specific implementation of the embodiment of the utility model. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model. These improvements and modifications should also be regarded as the scope of protection of this application.

Claims

1. A deep peak-shaving system for coal-fired power generation units based on compressed air energy storage, comprising a main engine steam turbine (1), wherein the main engine steam turbine (1) is connected to a step utilization steam turbine (2) and a feedwater pump steam turbine (7) respectively through steam extraction driving, characterized in that: The step is connected to an air compressor (3) by means of a driving shaft of a steam turbine (2); an air outlet of the air compressor (3) is sequentially connected to an air storage device (4) for storing compressed air and an expander (5) for performing work by means of a pipeline; the expander (5) is connected to a water feed pump steam turbine (7) by means of a driving shaft provided with a clutch.

2. According to claim 1, the deep peak regulation system of coal-fired power generation units based on compressed air energy storage is characterized in that: It also includes a heat supply system (9), wherein the step-utilizing steam turbine (2), the air compressor (3) and the expander (5) are respectively connected to the heat supply system (9) through pipelines.

3. According to claim 2, the deep peak regulation system of coal-fired power units based on compressed air energy storage is characterized in that: Valves are provided between the main engine steam turbine (1) and the step utilization steam turbine (2), between the main engine steam turbine (1) and the feed water pump steam turbine (7), between the air compressor (3) and the expander (5), and between the step utilization steam turbine (2) and the heating system (9).

4. According to claim 1, the deep peak regulation system of coal-fired power generation units based on compressed air energy storage is characterized in that: The clutch is a 3S clutch (6).

5. According to claim 1, the deep peak regulation system of coal-fired power generation units based on compressed air energy storage is characterized in that: The gas storage device (4) is a metal container or an artificial chamber.

6. According to claim 1, the deep peak regulation system of coal-fired power generation units based on compressed air energy storage is characterized in that: The air compressor (3) is a turbo compressor.

7. The deep peak regulation system of coal-fired power generation units based on compressed air energy storage according to claim 1 is characterized in that: It also includes a feed water pump (8) for driving the feed water pump steam turbine (7) to work.

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