Flexible peak regulation and frequency modulation system utilizing steam to drive gravity energy storage

Abstract

The utility model discloses a flexible peak regulation and frequency modulation system utilizing steam to drive gravity energy storage. The flexible peak regulation and frequency modulation system comprises a generator set, a back pressure turbine heat supply system and a gravity energy storage system. The generator set comprises a boiler, a main steam pipeline of the boiler communicates with a turbine high-pressure cylinder, an outlet of the turbine high-pressure cylinder communicates with the boiler through a pipeline and communicates with a turbine intermediate-pressure cylinder through a reheat steam pipeline, and an outlet of the turbine intermediate-pressure cylinder communicates with a turbine low-pressure cylinder. The back pressure machine heat supply system comprises a back pressure machine, the back pressure machine is communicated with a reheat steam pipeline through a reheat steam extraction pipeline, and the back pressure machine is communicated with the gravity energy storage system through a speed change device. The gravity energy storage system is driven by steam generated by the unit, when the load of the unit needs to be reduced, heat energy is converted into gravitational potential energy to be stored through the steam-driven gravity energy storage system, the amount of steam entering a steam turbine to do work is reduced, the power generation load is reduced, and the extracted steam is supplied with heat after being subjected to energy storage through the back pressure turbine. And gradient utilization of energy is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of peak regulation of coal-fired power plants, in particular to a flexible peak regulation and frequency regulation system utilizing steam-driven gravity energy storage. Background Art

[0002] To achieve the "dual carbon" goals, the power industry is stepping up efforts to build power stations powered by renewable energy, such as solar and wind. As installed capacity continues to grow, their share of the energy mix is ​​rapidly increasing. However, the intermittent and unstable nature of these renewable energy sources is becoming increasingly apparent, significantly impacting the stability and security of the power grid.

[0003] To mitigate the impact of the integration of renewable energy sources like solar and wind power on grid stability and ensure the stability and security of the power system, grid dispatchers often require coal-fired units to undertake peak-shaving and frequency-regulation tasks. However, due to aging equipment or their role in providing heating and other public services, the peak-shaving capabilities of some units are limited. Therefore, there is an urgent need to improve the peak-shaving and frequency-regulation capabilities of some existing units. Coupling coal-fired units with energy storage devices is an effective way to enhance these capabilities.

[0004] Patent application number CN202310069483 discloses a flexible peak-shaving system and method for thermal power plants coupled with gravity energy storage. This patent employs a gravity energy storage device placed between a large generator and the power grid, using electricity to drive a lifting mechanism to move a weight block, storing the electrical energy in the gravity energy storage device. However, the conversion of steam heat into electricity during power generation results in cooling losses, with approximately 50-60% of the energy being wasted, a well-known fact in the power industry. Therefore, using electricity to drive a gravity energy storage device is uneconomical and environmentally unfriendly.

[0005] Therefore, research and development of a flexible peak-shaving and frequency-regulating system using steam-driven gravity energy storage is of great significance for peak-shaving and frequency-regulating coal-fired power plants, maintaining grid stability, and energy conservation and environmental protection. Utility Model Content

[0006] To address the above technical issues, this utility model designs a flexible peak-shaving and frequency-regulating system that utilizes steam-driven gravity energy storage. This utility model utilizes steam generated by the unit to drive the gravity energy storage system. When the unit load needs to be reduced, steam is extracted from the unit to drive the gravity energy storage system, converting thermal energy into gravitational potential energy for storage. This reduces the amount of steam entering the steam turbine to perform work, lowering the power generation load. The extracted steam is then stored in a back pressure unit and then used for heat generation, achieving cascaded energy utilization.

[0007] The utility model adopts the following technical solutions:

[0008] A flexible peak-shaving and frequency-regulating system using steam-driven gravity energy storage, comprising a generator set, a back pressure heating system, and a gravity energy storage system;

[0009] The generator set includes a boiler, the main steam pipe of the boiler is connected to the high-pressure cylinder of the steam turbine, the outlet of the high-pressure cylinder of the steam turbine is connected back to the boiler through a pipeline, and is connected to the intermediate-pressure cylinder of the steam turbine through the reheat steam pipe of the boiler, and the outlet of the intermediate-pressure cylinder of the steam turbine is connected to the low-pressure cylinder of the steam turbine;

[0010] The back pressure machine heating system includes a back pressure machine, which is connected to the reheat steam pipeline through the reheat steam extraction pipeline. The back pressure machine is connected to the gravity energy storage system through a speed change device, and the speed change device transfers the kinetic energy of the back pressure machine to the gravity energy storage system.

[0011] Preferably, the gravity energy storage system includes a gravity energy storage device, which includes a gravity energy storage unit and a lifting device. The speed change device is connected to the lifting device and drives the lifting device to work. The lifting equipment transports the gravity energy storage unit to a high place to complete energy storage and realize peak regulation and frequency regulation of the unit.

[0012] As a preference, the high-pressure cylinder, medium-pressure cylinder and low-pressure cylinder of the steam turbine are connected to a large generator. The steam expands in the high, medium and low cylinders of the steam turbine to generate power and drive the large generator to rotate.

[0013] Preferably, the outlet of the back pressure machine is connected to a heat exchange station via a heating pipe. The heat exchange station transfers the heat of the exhaust steam to heating water, which is then supplied to heating users.

[0014] Preferably, the back pressure machine outlet is connected to regulating valve 1 through an industrial steam supply pipeline, and the steam pressure and temperature are adjusted by regulating valve 1 before being directly supplied to industrial steam users.

[0015] Preferably, the back pressure machine outlet is connected to the low-pressure cylinder of the steam turbine through a return pipe.

[0016] Preferably, the exhaust port of the low-pressure cylinder of the steam turbine is connected to a condenser, the condenser is connected to a low-pressure heater via a condensate pump, the low-pressure heater is connected to a deaerator, the deaerator is connected to a high-pressure heater via a feedwater pump, the high-pressure heater is connected back to the boiler via a pipeline, and the steam extraction port of the intermediate-pressure cylinder of the steam turbine is connected to the deaerator, completing one steam-water cycle.

[0017] Preferably, a regulating valve 2 is installed on the return pipe to adjust the steam pressure and temperature.

[0018] Preferably, the gravity energy storage system is connected to a small generator. The lifting equipment moves the gravity energy storage unit to a lower location and drives the small generator to rotate and generate electricity, thereby releasing energy and achieving peak power and frequency modulation of the unit.

[0019] The beneficial effects of the present invention are as follows: (1) the present invention directly utilizes steam thermal energy as a power source without converting it into electrical energy, thereby reducing cold source loss and being more energy-efficient; (2) the present invention utilizes a back pressure machine for heating and energy storage, thereby realizing cascade utilization of energy and making energy utilization more efficient; (3) the present invention controls the transport speed and transport quantity of the gravity energy storage unit through a speed change device for frequency modulation, which is convenient, fast and responsive; (4) the present invention designs three energy storage lines, which can be flexibly switched according to the operating requirements of the unit, and is suitable for heating units for heating and industrial steam supply, as well as for pure condensing units, with a wide range of applications; (5) the present invention can take into account deep peak regulation, peak regulation and frequency modulation, thereby realizing the transfer of energy in time and space. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the utility model;

[0021] In the figure: 1. Boiler; 1a. Main steam pipe; 1b. Reheat steam pipe; 1c. Reheat steam extraction pipe; 2. Steam turbine high-pressure cylinder; 3. Steam turbine intermediate-pressure cylinder; 4. Steam turbine low-pressure cylinder; 5. Large generator; 6. Condenser; 7. Condensate pump; 8. Low-pressure heater; 9. Deaerator; 10. Feedwater pump; 11. High-pressure heater; 12. Back pressure machine; 12a. Heating pipe; 12b. Industrial steam supply pipe; 12c. Return pipe; 13. Speed ​​change device; 14. Gravity energy storage device; 14a. Gravity energy storage unit; 14b. Lifting equipment; 15. Small generator; 16. Heat exchange station; 17. Control valve 1; 18. Control valve 2. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0023] Example: Figure 1 As shown, a flexible peak-shaving and frequency-regulating system using steam-driven gravity energy storage includes a generator set, a back pressure machine heating system, and a gravity energy storage system;

[0024] The generator set includes a boiler 1. The main steam pipe 1a of the boiler is connected to the high-pressure cylinder 2 of the steam turbine. The outlet of the high-pressure cylinder of the steam turbine is connected back to the boiler through a pipeline and is connected to the intermediate-pressure cylinder 3 of the steam turbine through the reheat steam pipe 1b of the boiler. The outlet of the intermediate-pressure cylinder of the steam turbine is connected to the low-pressure cylinder 4 of the steam turbine.

[0025] The back pressure machine heating system includes a back pressure machine 12, which is connected to the reheat steam pipeline through the reheat steam extraction pipeline 1c. The back pressure machine is connected to the gravity energy storage system through the speed change device 13, and the speed change device transfers the kinetic energy of the back pressure machine to the gravity energy storage system.

[0026] The gravity energy storage system includes a gravity energy storage device 14, which includes a gravity energy storage unit 14a and a lifting device 14b. The speed change device is connected to the lifting device and drives the lifting device to work. The lifting device transports the gravity energy storage unit to a high place to complete energy storage and realize peak regulation and frequency regulation of the unit.

[0027] The high-pressure cylinder of the steam turbine, the intermediate-pressure cylinder of the steam turbine, and the low-pressure cylinder of the steam turbine are connected to a large generator 5 .

[0028] The back pressure machine outlet is connected to the heat exchange station 16 through the heating pipe 12a.

[0029] The back pressure machine outlet is connected to the regulating valve 17 through the industrial steam supply pipeline 12b, and the steam pressure and temperature are adjusted by the regulating valve 1 before being directly supplied to industrial steam users.

[0030] The back pressure machine outlet is connected to the low pressure cylinder of the steam turbine through the return pipe 12c.

[0031] The exhaust port of the low-pressure cylinder of the steam turbine is connected to the condenser 6, the condenser is connected to the low-pressure heater 8 through the condensate pump 7, the low-pressure heater is connected to the deaerator 9, the deaerator is connected to the high-pressure heater 11 through the feed water pump 10, the high-pressure heater is connected back to the boiler through a pipeline, and the steam extraction port of the intermediate-pressure cylinder of the steam turbine is connected to the deaerator.

[0032] A regulating valve 2 18 is installed on the return pipeline.

[0033] The gravity energy storage system is connected to a small generator 15 .

[0034] The working principle of the flexible peak-shaving and frequency-regulating system using steam-driven gravity energy storage is as follows: the main steam generated by the boiler 1 enters the high-pressure cylinder 2 of the steam turbine through the main steam pipe 1a, and the main steam exhaust steam at the outlet of the high-pressure cylinder 2 of the steam turbine returns to the boiler 1 to be heated again to generate reheated steam, and the reheated steam enters the intermediate-pressure cylinder 3 of the steam turbine through the reheat steam pipe 1b, and the reheated steam exhaust steam enters the low-pressure cylinder 4 of the steam turbine, and the exhaust steam of the low-pressure cylinder 4 of the steam turbine enters the condenser 6 to condense into condensate, which is transported by the condensate pump 7 to the low-pressure heater 8 for heating and then to the deaerator 9 for deoxygenation. The deoxygenated water at the outlet of the deaerator 9 is transported by the feed water pump 10 to the high-pressure heater 11 for heating, and the feed water finally returns to the boiler 1, and after being heated in the boiler 1, the feed water generates main steam and enters the next steam-water cycle. The steam turbine high-pressure cylinder 2, the steam turbine intermediate-pressure cylinder 3, and the steam turbine low-pressure cylinder 4 are connected to a large generator 5. The main steam and the reheated steam expand in the high-pressure, intermediate-pressure, and low-pressure cylinders of the steam turbine, and perform work to drive the large generator 5 to rotate and generate electrical energy, thereby realizing power generation of the unit.

[0035] The unit heat supply peak regulation, gravity energy storage system energy storage:

[0036] When a deep peak-shaving command is received from the power grid, some reheated steam is extracted through the reheat steam extraction pipeline 1c and fed into the back pressure unit 12. The steam expands and produces work in the back pressure unit 12, causing the exhaust steam pressure and temperature to drop. When the exhaust steam is used according to the first utilization route, it flows through the heating pipeline 12a to the heat exchange station 16, where it heats heating water for heating users. When the exhaust steam is used according to the second utilization route, it is transported through the industrial steam supply pipeline 12b, where its pressure and temperature are adjusted by the regulating valve 17, before being directly supplied to industrial users. The exhaust steam is used according to the first and second utilization routes to meet different heating needs.

[0037] After extracting part of the reheated steam, the amount of steam entering the turbine intermediate pressure cylinder 3 and the turbine low pressure cylinder 4 is reduced, the working capacity of the unit itself is reduced, the power generation is reduced, and deep peak regulation is completed.

[0038] The reheated steam expands and performs work in the back pressure machine 12, which drives the speed change device 13 to rotate. The speed change device 13 drives the lifting equipment 14b to move the gravity energy storage unit 14a to a higher place, completing the energy storage process.

[0039] The unit is not used for peak regulation due to heat supply, and the gravity energy storage system stores energy:

[0040] When a deep peak-shaving command is received from the power grid, some reheated steam is extracted through reheat steam extraction pipe 1c and fed into back compressor 12. There, the steam expands and produces work, causing the exhaust pressure and temperature to drop. When the exhaust steam is used according to the third utilization route, it passes through return pipe 12c, where its pressure and temperature are adjusted by regulating valve 2 18 before returning to the low-pressure cylinder 4 of the steam turbine to generate power.

[0041] After extracting part of the reheated steam, the amount of steam entering the intermediate pressure cylinder 3 of the steam turbine is reduced, the working capacity of the unit itself is reduced, the power generation is reduced, and deep peak regulation is completed.

[0042] The reheated steam expands and performs work in the back pressure machine 12, which drives the speed change device 13 to rotate. The speed change device 13 drives the lifting equipment 14b to move the gravity energy storage unit 14a to a higher place, completing the energy storage process.

[0043] At the peak of the unit, the gravity energy storage system releases energy:

[0044] When receiving the peak instruction from the grid dispatch, the lifting equipment 14b moves the gravity energy storage unit 14a to a lower place, and at the same time drives the small generator 15 to rotate and generate electricity. The gravity energy storage device 14 completes the energy release and achieves the peak.

[0045] Unit frequency regulation:

[0046] When the generator set receives the grid frequency regulation instruction, it adjusts the reheat steam extraction amount along the reheat steam extraction pipe 1c, reduces or increases the steam amount entering the turbine intermediate pressure cylinder 3 and the turbine low pressure cylinder 4, and completes the unit frequency regulation.

[0047] Gravity energy storage system frequency modulation:

[0048] When the generator set receives the grid frequency regulation instruction, the speed change device 13 controls the number or speed of the lifting equipment 14b to move the gravity energy storage unit 14a, thereby controlling the power generation of the small generator 15 and completing the frequency regulation of the gravity energy storage system.

[0049] The embodiment described above is only a preferred solution of the present invention and does not limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solutions described in the claims.

Claims

1. A flexible peak-shaving and frequency-regulating system using steam-driven gravity energy storage, characterized by: It includes a generator set, a back pressure machine heating system and a gravity energy storage system; The generator set includes a boiler, the main steam pipe of the boiler is connected to the high-pressure cylinder of the steam turbine, the outlet of the high-pressure cylinder of the steam turbine is connected back to the boiler through a pipeline, and is connected to the intermediate-pressure cylinder of the steam turbine through the reheat steam pipe of the boiler, and the outlet of the intermediate-pressure cylinder of the steam turbine is connected to the low-pressure cylinder of the steam turbine; The back pressure machine heating system includes a back pressure machine, which is connected to the reheat steam pipeline through the reheat steam extraction pipeline. The back pressure machine is connected to the gravity energy storage system through a speed change device, and the speed change device transfers the kinetic energy of the back pressure machine to the gravity energy storage system.

2. The flexible peak-shaving and frequency-modulating system using steam-driven gravity energy storage according to claim 1 is characterized in that: The gravity energy storage system includes a gravity energy storage device, which includes a gravity energy storage unit and a lifting device. The speed change device is connected to the lifting device and drives the lifting device to work. The lifting device transports the gravity energy storage unit to a high place to complete energy storage and realize peak regulation and frequency regulation of the unit.

3. The flexible peak-shaving and frequency-modulating system using steam-driven gravity energy storage according to claim 1 is characterized in that: The steam turbine high-pressure cylinder, the steam turbine intermediate-pressure cylinder and the steam turbine low-pressure cylinder are connected to a large generator.

4. The flexible peak-shaving and frequency-modulating system using steam-driven gravity energy storage according to claim 1 is characterized in that: The back pressure machine outlet is connected to the heat exchange station through a heating pipeline.

5. The flexible peak-shaving and frequency-modulating system using steam-driven gravity energy storage according to claim 1 is characterized in that: The outlet of the back pressure machine is connected to the regulating valve 1 through the industrial steam supply pipeline, and the steam pressure and temperature are adjusted by the regulating valve 1 and then directly supplied to industrial steam users.

6. The flexible peak-shaving and frequency-modulating system using steam-driven gravity energy storage according to claim 1 is characterized in that: The back pressure machine outlet is connected to the low-pressure cylinder of the steam turbine through a return pipeline.

7. The flexible peak-shaving and frequency-modulating system using steam-driven gravity energy storage according to claim 1 is characterized in that: The exhaust port of the low-pressure cylinder of the steam turbine is connected to the condenser, the condenser is connected to the low-pressure heater through the condensate pump, the low-pressure heater is connected to the deaerator, the deaerator is connected to the high-pressure heater through the feed water pump, the high-pressure heater is connected back to the boiler through a pipeline, and the steam extraction port of the intermediate-pressure cylinder of the steam turbine is connected to the deaerator.

8. The flexible peak-shaving and frequency-modulating system using steam-driven gravity energy storage according to claim 6 is characterized in that: A second regulating valve is installed on the return pipeline.

9. The flexible peak-shaving and frequency-modulating system using steam-driven gravity energy storage according to claim 1 is characterized in that: The gravity energy storage system is connected to a small generator.

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