Deep peak regulation gas-steam combined cycle thermoelectricity and electricity coupling combined supply system

Abstract

The utility model discloses a deep peak regulation gas-steam combined cycle thermoelectric decoupling combined supply system which comprises a combined cycle unit, a bypass unit and an electric heat storage device. The combined cycle unit is a gas-steam combined cycle generator set and is composed of a gas turbine, a steam turbine, a waste heat boiler and a generator. The bypass unit is a bypass steam turbine generator unit, and the electric heat storage device is an electric boiler heat storage device. When the unit enters a deep peak regulation stage, cylinder switching can be carried out through a 3S clutch, a bypass unit is started for grid-connected operation, charged heat storage can also be started in the power grid off-peak period, multi-dimensional peak regulation energy storage is achieved, good economic benefits and social benefits can be generated, and good engineering application prospects are achieved.

Description

Technical Field

[0001] The utility model relates to the field of combined cycle mechanical heat and electric energy storage, specifically a deep peak-shaving gas-steam combined cycle heat and power decoupling supply system. Background Art

[0002] Gas-steam combined cycle power plants primarily consist of gas turbines, waste heat boilers, steam turbines, and generators. They offer advantages such as rapid startup, flexible regulation, high efficiency, and low energy consumption, playing a crucial role in power grid peak regulation. Gas turbines are typically located near cities. As key power sources during the peak summer load period, they meet the need for clean electricity peak regulation. During the winter heating season, they often serve as a crucial heat source for cities. With the accelerated pace of urbanization, industrialization, and the development of new energy sources, the power grid is facing continued expansion. Achieving safe and deep peak regulation has become a crucial factor in maintaining the stability of the entire power system.

[0003] In recent years, the average wind and solar curtailment rate in the "Three Norths" region has reached nearly 30%. To accommodate the integration of renewable energy, the power grid has required thermal power plants to increase their peak-shaving capabilities. This conflicts with the traditional heat-based electricity generation model. Thermal-electric decoupling aims to address this peak-shaving challenge in this heat-based electricity generation model. This approach ensures that while maintaining winter heating for residents, it also provides peak-shaving functionality to accommodate the integration of renewable energy. This ensures that even when power plant loads decrease due to grid regulation, the heat supply can still meet the network's needs.

[0004] Currently commonly used thermoelectric decoupling solutions have several issues: Low-pressure cylinder zero-output technology cannot fully achieve hotspot structures, and blade dynamic stress and water erosion safety indicators require further demonstration; high-back-pressure dual-rotor technology requires redesigning the low-pressure cylinder flow passage, requiring significant investment and maintenance, and placing high demands on system stability; while simple turbine bypass heating, while offering strong thermoelectric decoupling capabilities, is less economical and requires high operational reliability. Based on this analysis, a more reliable and efficient thermoelectric decoupling solution is urgently needed. Utility Model Content

[0005] The purpose of this utility model is to provide a deep peak-shaving gas-steam combined cycle decoupled heat and power supply system. This utility model is achieved by:

[0006] A deep peak-shaving gas-steam combined cycle decoupled heat and power supply system is characterized in that: the system includes a combined cycle unit, a bypass unit and an electric heat storage device, the combined cycle unit is used to provide steam power generation to the bypass unit when the load is low; the bypass unit is used to heat and store energy in the electric heating heat storage device when the system is low load.

[0007] Furthermore, the combined cycle unit is a gas-steam combined cycle power generation unit, which consists of a waste heat boiler, a gas turbine, a compressor, a high-pressure cylinder, a medium-pressure cylinder, a first generator, and a low-pressure cylinder. The connection method of the combined cycle unit is: the air filter enters from the compressor inlet k for pressurization, the natural gas pressure regulating station enters from the end of the compressor, the high-temperature flue gas after the mixed combustion of air and natural gas enters the gas turbine to do work, the exhaust smoke enters the waste heat boiler, the condensate pump is connected to the feed water inlet f of the waste heat boiler, and after being heated by the waste heat boiler, it is connected to the deaerator from the outlet a. The feed water at the deaerator outlet is divided into three streams, which pass through the low-pressure feed water pump, the medium-pressure feed water pump and the high-pressure feed water pump respectively, and return to the waste heat boiler from the waste heat boiler inlets b, d, and e respectively, and are divided again after being heated. They flow out from the waste heat boiler outlets g, h, and i respectively; among them, the high-pressure steam flowing out from i enters the high-pressure cylinder through the high-pressure cylinder inlet m; the medium-pressure steam flowing out from h merges with the steam from the high-pressure cylinder outlet I and then enters the low-pressure cylinder from the inlet n; the steam flowing out of the medium-pressure cylinder enters the low-pressure cylinder from q, enters the bypass unit from r, and merges with the steam flowing out of the waste heat boiler outlet g and then enters the heating first station from the inlet t; after flowing out of the low-pressure cylinder, the steam is discharged through the condenser outlet s, and after being pressurized by the condensate pump, it enters the next cycle; the steam from the waste heat boiler outlet c is used as the feed water heating steam for the deaerator; the bypass before the low-pressure cylinder inlet r is connected to the bypass unit, and the high-voltage line is introduced from before the transformer to connect to the electric heat storage device, and a path of heated feed water is drawn out from before the low-pressure feed water pump inlet a to enter the electric heat storage device.

[0008] Furthermore, the combined cycle unit can be arranged in a single-shaft or multi-shaft arrangement; wherein the low-pressure cylinder of the steam turbine is arranged at the outer end of the first generator and is connected to the first generator through a 3S clutch.

[0009] Furthermore, the bypass unit is a bypass steam turbine generator unit, which is a single-cylinder condensing steam turbine, coaxially connected to the second generator, and the steam enters the low-pressure cylinder and the single-cylinder condensing steam turbine from the outlet of the intermediate pressure cylinder through inlets q and r respectively, and the two are arranged in parallel; the exhaust steam of the low-pressure cylinder and the exhaust steam of the single-cylinder condensing steam turbine enter the condenser in two parallel ways through inlets x and y respectively, and the two share the condenser.

[0010] Furthermore, the electric heat storage device includes an electric boiler heat storage device, and the heat storage medium in the electric boiler heat storage device is hot water. The connection method is: a stream of hot water is drawn out from the outlet of the low-pressure water feed pump, connected to the electric boiler heat storage device from the inlet o, flows out from the outlet p after heat exchange, passes through the heating valve, and enters the heating first station from the inlet v. The water outlet of the heating first station flows back to the condenser from the outlet u through the drain pump.

[0011] Compared with the prior art, the beneficial effects of the present invention are:

[0012] This utility model couples and controls the gas-steam combined cycle generator set, the bypass turbine generator set, and the electric heat storage device. When the unit enters the deep peak-shaving stage (operating at loads below 30% of rated load), for the safety of the low-pressure cylinder, the 3S clutch can be used to cut the cylinder and start the bypass unit for grid-connected operation. At this time, the exhaust steam from the medium-pressure cylinder can enter the condenser through the bypass turbine. Since the bypass turbine is designed for combined cycle units with loads below 30%, it can operate safely at around 10% load of the combined cycle unit. In addition, the combined power supply system can be equipped with or without an electric heat storage device. In the case of an electric heat storage device, heat can be stored during off-peak hours of the grid and released during peak hours of the grid, achieving thermal and electrical decoupling, taking into account both reliability and flexibility, and having good practical engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 This is a structural diagram of a deep peak-shaving gas-steam combined cycle heat and power decoupling system (including electric heat storage device);

[0015] Figure 2 It is a structural diagram of a deep peak-shaving gas-steam combined cycle heat and power decoupling system (excluding electric heat storage device).

[0016] Among them: 1. Waste heat boiler, 2. Gas turbine, 3. Compressor, 4. High-pressure cylinder, 5. Medium-pressure cylinder, 6. First generator, 7. 3S clutch, 8. Low-pressure cylinder, 9. Condenser, 10. Single-cylinder bypass steam engine, 11. Second generator, 12. Natural gas pressure regulating station, 13. Air filter, 14. Deaerator, 15. Low-pressure feed water pump, 16. Medium-pressure feed water pump, 17. High-pressure feed water pump, 18. Electric boiler heat storage device, 19. First transformer, 20. Second transformer, 21. High-voltage power grid, 22. Low-pressure steam supply valve, 23. Medium-pressure steam supply valve, 24. Condensate pump, 25. First heating station, 26. Drain pump, 27. Heating valve. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the implementation methods of the present invention clearer, the technical solutions in the implementation methods of the present invention will be clearly and completely described below in combination with the drawings in the implementation methods of the present invention. Obviously, based on the implementation methods in the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] a~w are the import and export numbers of each module.

[0019] Example 1

[0020] A deep peak-shaving gas-steam combined cycle decoupled heat and power system. In this embodiment, the system includes a combined cycle unit, a bypass unit, and an electric heat storage device. A bypass line is connected to the bypass unit before the low-pressure cylinder inlet r of the combined cycle unit. A high-voltage line is introduced before the transformer 20 to connect to the electric heat storage device. A line of heated feedwater is drawn before the low-pressure feedwater pump 15 inlet a to enter the electric heat storage device.

[0021] The combined cycle unit is a gas-steam combined cycle generator set, which consists of a waste heat boiler 1, a gas turbine 2, a compressor 3, a high-pressure cylinder 4, an intermediate-pressure cylinder 5, a first generator 6, and a low-pressure cylinder 8;

[0022] The combined cycle unit is connected as follows: the condensate pump 24 is connected to the feed water inlet f, and after heating, it is connected to the deaerator 14 from the outlet a. The feed water from the deaerator 14 outlet is divided into three streams, which are respectively passed through the low-pressure feed water pump 15, the medium-pressure feed water pump 16, and the high-pressure feed water pump 17, and enter the waste heat boiler 1 from the inlets b, d, and e respectively. After being heated, it flows out from the outlets g, h, and i respectively. Among them, the high-pressure steam flowing out from the outlet i enters the high-pressure cylinder 4 through the inlet m of the high-pressure cylinder 4; the medium-pressure steam flowing out from the outlet h merges with the steam at the outlet I of the high-pressure cylinder 4 and enters the low-pressure cylinder 8 from the inlet n. The steam flowing out of the intermediate pressure cylinder 5 enters the low pressure cylinder 8 from q, enters the bypass unit from r, and merges with the steam flowing out of the outlet g of the waste heat boiler 1 before entering the heating first station 25 from inlet t. The steam flowing out of the low pressure cylinder 8 is discharged from the condenser 9 at s, and after being pressurized by the condensate pump 24, it enters the next cycle. The steam at the outlet c of the waste heat boiler is used as feed water heating steam for the deaerator 14. The combined cycle unit can be arranged in a single shaft or a multi-shaft arrangement. The low pressure cylinder 8 of the steam turbine is arranged at the outer end of the first generator 6 and is connected to the first generator 6 through the 3S clutch 7.

[0023] The bypass unit is a bypass steam turbine generator unit, which is a single-cylinder condensing steam turbine and is coaxially connected to the second generator 11;

[0024] Steam from the outlet of the intermediate pressure cylinder 5 enters the low pressure cylinder 8 and the single cylinder condensing steam turbine through the inlets q and r respectively, and the two are arranged in parallel;

[0025] The exhaust steam of low pressure cylinder 8 and the exhaust steam of single cylinder condensing steam turbine enter condenser 9 through inlet x and inlet y respectively, and the two share the same condenser;

[0026] This bypass steam turbine is designed for combined cycle units with loads below 30%;

[0027] The electric heat storage device includes an electric boiler heat storage device 18. The heat storage medium in the electric boiler heat storage device 18 is hot water. The connection method is as follows: hot water is drawn from the outlet of the low-pressure water pump 15, connected to the electric boiler heat storage device 18 at inlet o, and after heat exchange, flows out of outlet p, passes through the heating valve 27, and enters the heating primary station 25 at inlet v. The water from the heating primary station flows back to the condenser 9 through outlet u through the drain pump 26.

[0028] In this embodiment, when the unit enters the deep peak load regulation stage and the unit load is lower than 30% of the rated load, for the safety of the low-pressure cylinder 8, the 3S clutch 7 can be used to cut the cylinder and start the bypass unit for grid connection operation. At this time, the exhaust steam of the intermediate-pressure cylinder can enter the condenser 9 through the single-cylinder bypass steam engine 10;

[0029] In this embodiment, the bypass steam turbine is designed for combined cycle units with a load below 30%, so it can operate safely around 10% load of the combined cycle unit;

[0030] In this embodiment, an electric heat storage device is provided. During off-peak hours, hot water is introduced from the outlet of the low-pressure water pump 15 through the inlet of the electric boiler heat storage device 18, and then heated by electricity from the high-voltage power grid. During peak hours, the hot water heat is released for heating.

[0031] Example 2

[0032] In this embodiment, there is no need for additional electricity and heat storage for peak regulation, so the electric heat storage device can be omitted. In this case, the system is relatively simple, and other functions are the same as in embodiment 1.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A deep peak-shaving gas-steam combined cycle decoupled heat and power supply system, characterized by: The system includes a combined cycle unit, a bypass unit and an electric heat storage device. The combined cycle unit is used to provide steam power generation to the bypass unit when the load is low; the bypass unit is used to heat and store energy in the electric heating heat storage device when the system is under low load. The combined cycle unit is a gas-steam combined cycle generator set, which consists of a waste heat boiler (1), a gas turbine (2), a compressor (3), a high-pressure cylinder (4), a medium-pressure cylinder (5), a first generator (6), and a low-pressure cylinder (8). The connection method of the combined cycle unit is as follows: an air filter (13) enters from the inlet k of the compressor (3) for pressurization, a natural gas pressure regulating station (12) enters from the end of the compressor (3), high-temperature flue gas after the mixed combustion of air and natural gas enters the gas turbine (2) to perform work, and exhaust gas enters the waste heat boiler (1), a condensate pump (24) is connected to the feed water inlet f of the waste heat boiler (1), and after being heated by the waste heat boiler (1), it is connected to the deaerator (14) from the outlet a, and the feed water at the outlet of the deaerator (14) is divided into three streams, which respectively pass through the low-pressure feed water pump (15), the medium-pressure feed water pump (16) and the high-pressure feed water pump (17), and respectively return to the waste heat boiler (1) from the inlets b, d, and e of the waste heat boiler (1). 1), and after being heated, they flow out from the outlets g, h, and i of the waste heat boiler (1) respectively; among them, the high-pressure steam flowing out from i enters the high-pressure cylinder (4) through the inlet m; the medium-pressure steam flowing out from h merges with the steam from the outlet i of the high-pressure cylinder (4) and then enters the low-pressure cylinder (8) through the inlet n; the steam flowing out of the medium-pressure cylinder (5) enters the low-pressure cylinder (8) through q, enters the bypass unit through r, and merges with the steam flowing out of the outlet g of the waste heat boiler (1) and then enters the heating main unit through the inlet t. Station (25); steam flows out of the low-pressure cylinder (8) and is discharged through the outlet s of the condenser (9), and after being pressurized by the condensate pump (24), it enters the next cycle; the steam at the outlet c of the waste heat boiler (1) is used as the feed water heating steam for the deaerator (14); the bypass before the inlet r of the low-pressure cylinder (8) is connected to the bypass unit, and the high-voltage line is introduced before the transformer (20) to connect to the electric heat storage device, and the heated feed water is drawn out from before the inlet a of the low-pressure feed water pump (15) to enter the electric heat storage device.

2. The deep peak-shaving gas-steam combined cycle decoupled heat and power supply system according to claim 1, characterized in that: The combined cycle unit can be arranged in a single shaft or a multi-shaft arrangement; wherein the low-pressure cylinder (8) of the steam turbine is arranged at the outer end of the first generator (6) and is connected to the first generator (6) through a 3S clutch (7).

3. The deep peak-shaving gas-steam combined cycle decoupled heat and power supply system according to claim 1, characterized in that: The bypass unit is a bypass steam turbine generator unit (10), which is a single-cylinder condensing steam turbine and is coaxially connected to a second generator (11). Steam enters the low-pressure cylinder (8) and the single-cylinder condensing steam turbine from the outlet of the intermediate-pressure cylinder (5) through inlets q and r, respectively, and the two are arranged in parallel; the exhaust steam of the low-pressure cylinder (8) and the exhaust steam of the single-cylinder condensing steam turbine enter the condenser (9) in two parallel paths through inlets x and y, respectively, and the two share the condenser.

4. The deep peak-shaving gas-steam combined cycle decoupled heat and power supply system according to claim 1, characterized in that: The electric heat storage device comprises an electric boiler heat storage device (18), wherein the heat storage medium in the electric boiler heat storage device (18) is hot water, and the connection method is as follows: a stream of hot water is drawn out from the outlet of the low-pressure water supply pump (15), connected to the electric boiler heat storage device (18) from the inlet o, flows out from the outlet p after heat exchange, passes through the heating valve (27), enters the heating first station (25) from the inlet v, and the water outlet of the heating first station (25) flows back to the condenser (9) from the outlet u through the drain pump (26).

Images