A precise heat extraction combined cycle intake cooling and heating circulation system

Abstract

The present invention relates to the technical field of gas-steam combined cycles, and more particularly to a precise heat extraction combined cycle inlet cooling and heating circulation system, comprising a gas turbine, the outlet of which is connected to a flue gas duct, the terminal of which is connected to a chimney; a low-temperature economizer, a high-temperature economizer, a steam generator, and a superheater are sequentially arranged within the flue gas duct, the low-temperature economizer, the high-temperature economizer, the steam generator, and the superheater being connected end to end, with a power generation assembly disposed between the low-temperature economizer and the superheater; and a heat extractor disposed between the low-temperature economizer and the high-temperature economizer, the heat extractor being connected to a temperature regulation assembly. The present invention can achieve the purpose of temperature control of the air at the gas turbine inlet.

Description

Technical Field

[0001] The present invention relates to the technical field of gas-steam combined cycle technology, and in particular to a precise heat extraction combined cycle intake cooling and heating circulation system. Background Art

[0002] Renewable energy systems, primarily based on solar and wind power, are characterized by randomness, volatility, and intermittency. Large-scale grid integration requires real-time output adjustments from other power systems to accommodate the frequent fluctuations in renewable energy output. Gas turbines, with their high efficiency, low pollution, and excellent peak-shaving performance, are ideal peak-shaving power sources for renewable energy. They can be widely integrated with various energy systems to adapt to fluctuating electricity load demands.

[0003] Gas-steam combined cycle power generation technology fully utilizes the energy of flue gas at all levels of quality and is the primary cycle for gas turbine power generation in my country. In addition to consuming natural gas, the gas-steam combined cycle also requires a large amount of ambient air. Since gas turbines are constant-volume power machines, their performance is closely related to air density. Therefore, the air temperature at the gas turbine inlet significantly affects gas turbine efficiency and power generation.

[0004] During summer heatwaves, when the unit operates under these conditions, rising air temperature reduces air density, increases specific volume, and reduces the mass flow of air into the gas turbine, leading to a decrease in gas turbine power generation. Simultaneously, rising ambient temperature reduces the compressor's pressure ratio, increasing power consumption and causing compressor efficiency to decline, further reducing gas turbine power generation. This dual deterioration in power generation and efficiency inevitably leads to increased pollution. The high temperatures of summer coincide with peak electricity demand, creating an inherent conflict between power supply and demand.

[0005] During winter temperatures, units typically adjust the power generation load by adjusting the opening of variable guide vanes. When the unit operates at partial load during this period, the opening of the variable guide vanes decreases as the inlet air temperature drops. This means that as the ambient temperature decreases and the air density increases, the guide vane opening decreases under certain load conditions, causing the operating state to deviate further from the design condition and significantly reducing efficiency.

[0006] In summary, gas-steam combined cycles typically operate at full load during the hot summer months and at partial load during the spring, autumn, and winter. Excessively high or low ambient temperatures can severely impact unit efficiency and power generation. Therefore, controlling the air temperature at the gas turbine inlet can effectively ensure safe and efficient year-round operation, thereby avoiding the need for new units. Therefore, a precise heat extraction combined cycle inlet air cooling and heating system is urgently needed. Summary of the Invention

[0007] The purpose of the present invention is to provide a precise heat extraction combined cycle intake cooling and heating circulation system to solve the above problems and achieve the purpose of controlling the temperature of the air at the gas turbine inlet.

[0008] To achieve the above-mentioned object, the present invention provides the following solution: a precise heat extraction combined cycle intake cooling and heating circulation system, comprising a gas turbine, wherein the outlet end of the gas turbine is connected to a flue gas duct, and the end of the flue gas duct is connected to a chimney;

[0009] A low-temperature economizer, a high-temperature economizer, a steam generator and a superheater are sequentially arranged in the flue gas duct, and the low-temperature economizer, the high-temperature economizer, the steam generator and the superheater are sequentially connected end to end, and a power generation component is provided between the low-temperature economizer and the superheater;

[0010] A heat exchanger is provided between the low-temperature economizer and the high-temperature economizer, and the heat exchanger is connected to a temperature regulating component.

[0011] Preferably, the temperature regulating component includes a generator, the heat extractor is connected to the generator to form a loop, the generator is connected in series with an air heat exchanger, a throttle valve, a water heat exchanger, and an absorber, the absorber is connected to an intermediate heat exchanger to form a loop, the intermediate heat exchanger is connected to the generator to form a loop, the water heat exchanger is connected to an air intake heat exchanger to form a loop, and the air intake heat exchanger is located at the air intake end of the gas turbine.

[0012] Preferably, the pipeline between the generator and the air heat exchanger is connected in series with a first tee, a sixth valve and a second tee in sequence, and the pipeline between the water heat exchanger and the absorber is connected in series with a third tee, a fifth valve and a fourth tee in sequence, the first tee is connected to the third tee, and the second tee is connected to the fourth tee.

[0013] Preferably, a third valve is provided on the liquid inlet pipeline between the water heat exchanger and the air intake heat exchanger, and a second booster pump and a fourth valve are provided on the liquid return pipeline between the water heat exchanger and the air intake heat exchanger.

[0014] Preferably, a solution pump is provided on the liquid return pipeline between the absorber and the intermediate heat exchanger.

[0015] Preferably, a first valve is provided on the liquid inlet pipeline between the heat extractor and the generator, and a first booster pump and a second valve are provided on the liquid return pipeline between the heat extractor and the generator.

[0016] Preferably, the power generation component includes a steam turbine, a condenser and a condensate pump connected in series in sequence, the air inlet end of the steam turbine is connected to the superheater, the liquid outlet end of the condensate pump is connected to the low-temperature economizer, and a cooling tower and a circulating water pump are connected in series between the water outlet end and the return water end of the condenser.

[0017] The present invention has the following technical advantages: Based on the hierarchical distribution of flue gas heat, the present invention extracts a suitable driving heat source between the high and low temperature economizers in the flue gas flow to cool the unit's intake air during high summer temperatures and to heat the unit's intake air during low winter temperatures. This invention avoids the use of high-quality steam or high-temperature flue gas as a driving heat source, effectively improving the overall performance (power generation and efficiency) of the gas-steam turbine combined cycle, maintaining stable power output under high summer temperatures, and resolving the inherent contradiction between increased summer electricity load and reduced system power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work.

[0019] Figure 1 It is a schematic diagram of the structure of the present invention;

[0020] Figure 2 A performance comparison chart of the present invention with that of the prior art gas turbine;

[0021] Figure 3 This is a performance comparison chart of the present invention compared with the prior art gas-steam combined cycle;

[0022] Among them, 1. gas turbine; 2. steam turbine; 3. condenser; 4. condensate pump; 5. high-temperature economizer; 6. steam generator; 7. superheater; 8. circulating water pump; 9. cooling tower; 10. chimney; 11. low-temperature economizer; 12. heat extractor; 13. first booster pump; 14. generator; 15. air heat exchanger; 16. throttle valve; 17. water heat exchanger; 18. absorber; 19. solution pump; 20. intermediate heat exchanger; 21. second booster pump; 22. air intake heat exchanger; 101. first valve; 102. second valve; 201. third valve; 202. fourth valve; 301. fifth valve; 302. sixth valve; 401. first tee; 501. second tee; 402. third tee; 502. fourth tee. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Reference Figure 1-3 The present invention provides a precise heat extraction combined cycle air intake cooling and heating circulation system, comprising a gas turbine 1, wherein the outlet end of the gas turbine 1 is connected to a flue gas duct, and the end of the flue gas duct is connected to a chimney 10;

[0026] A low-temperature economizer 11, a high-temperature economizer 5, a steam generator 6, and a superheater 7 are sequentially arranged in the flue gas duct, and the low-temperature economizer 11, the high-temperature economizer 5, the steam generator 6, and the superheater 7 are sequentially connected end to end, and a power generation component is provided between the low-temperature economizer 11 and the superheater 7;

[0027] A heat exchanger 12 is provided between the low-temperature economizer 11 and the high-temperature economizer 5 , and the heat exchanger 12 is connected to a temperature regulating component.

[0028] The gas turbine 1 generates heat, which is concentrated in the flue gas duct. The heat is used to heat the water through the low-temperature economizer 11, the high-temperature economizer 5, the steam generator 6 and the superheater 7, so that the water is converted into steam. The steam drives the power generation components to generate electricity. The exhaust gas is discharged from the chimney 10. The heat extractor 12 is arranged between the low-temperature economizer 11 and the high-temperature economizer 5. Based on the principle of step-by-step distribution of flue gas heat, heat of appropriate quality is extracted to participate in the regulation of the air temperature at the inlet end of the gas turbine 1. The temperature regulation component is used to regulate the temperature of the air at the inlet end of the gas turbine 1.

[0029] Further optimization scheme, the temperature adjustment component includes a generator 14, the heat extractor 12 is connected to the generator 14 and forms a loop, the generator 14 is connected in series with an air heat exchanger 15, a throttle valve 16, a water heat exchanger 17, an absorber 18, and the absorber 18 is connected with an intermediate heat exchanger 20 to form a loop, refer to Figure 1 The right end of the intermediate heat exchanger 20 is connected to the top port, and the left end is connected to the bottom port. The intermediate heat exchanger 20 is connected to the generator 14 to form a loop. The water heat exchanger 17 is connected to the air intake heat exchanger 22 to form a loop. The air intake heat exchanger 22 is located at the intake end of the gas turbine 1. The heat extractor 12 is used to absorb heat from the flue gas. This heat heats the medium water in the pipeline, which generates steam. The steam flows into the generator 14 for heat exchange.

[0030] Specifically, a fan is provided at the bottom of the air intake heat exchanger 22 .

[0031] To further optimize the solution, the pipeline between the generator 14 and the air heat exchanger 15 is connected in series with the first tee 401, the sixth valve 302 and the second tee 501 in sequence, and the pipeline between the water heat exchanger 17 and the absorber 18 is connected in series with the third tee 402, the fifth valve 301 and the fourth tee 502 in sequence, the first tee 401 and the third tee 402 are connected, and the second tee 501 and the fourth tee 502 are connected.

[0032] Specifically, the first tee 401 is disposed close to the generator 14 , and the third tee 402 is disposed close to the water heat exchanger 17 .

[0033] To further optimize the solution, a third valve 201 is provided on the liquid inlet pipeline between the water heat exchanger 17 and the air intake heat exchanger 22 , and a second booster pump 21 and a fourth valve 202 are provided on the liquid return pipeline between the water heat exchanger 17 and the air intake heat exchanger 22 .

[0034] To further optimize the solution, a solution pump 19 is provided on the liquid return pipeline between the absorber 18 and the intermediate heat exchanger 20 .

[0035] To further optimize the solution, a first valve 101 is provided on the liquid inlet pipeline between the heat collector 12 and the generator 14 , and a first booster pump 13 and a second valve 102 are provided on the liquid return pipeline between the heat collector 12 and the generator 14 .

[0036] A further optimized solution includes a steam turbine 2, a condenser 3, and a condensate pump 4 connected in series. The steam turbine 2's air inlet is connected to a superheater 7, and the condensate pump 4's liquid outlet is connected to a low-temperature economizer 11. A cooling tower 9 and a circulating water pump 8 are connected in series between the condenser 3's water outlet and return water outlet. Steam drives the steam turbine 2 to generate electricity. After condensation and cooling, the steam is pumped by the condensate pump 4 to the low-temperature economizer 11 for preheating.

[0037] The present invention operates as follows: When the unit is operating during high summer temperatures, the first valve 101, second valve 102, third valve 201, fourth valve 202, fifth valve 301, and sixth valve 302 are opened, and the intake air cooling system is activated. Intermediate water flows into heat exchanger 12. Heated by the flue gas, the intermediate water forms steam, which flows into generator 14. The steam generated in generator 14 flows through air heat exchanger 15, throttle valve 16, and water heat exchanger 17 before entering absorber 18, where it is absorbed. Simultaneously, the solution in absorber 18 becomes a dilute solution, which can be a lithium bromide / water solution, an ammonia / water solution, or another working medium. After releasing latent heat in generator 14, the heat-extracting working medium vapor becomes liquid water and flows back to heat exchanger 12 to continue absorbing heat. Simultaneously, chilled water at 6-8°C is produced in water heat exchanger 17. This chilled water flows into air intake heat exchanger 22 to cool the ambient air. The heated chilled water then flows back to water heat exchanger 17 to release heat. After cooling, the ambient air flows into the gas turbine system, where it is heated and pressurized. During summer operation, the air heat exchanger 15 functions as a condenser, while the water heat exchanger 17 functions as an evaporator. Valves are installed between the first and third tees 401 and 402, and between the second and fourth tees 501 and 502. During summer operation, these valves are open.

[0038] When the unit operates during winter cold weather, the first valve 101, second valve 102, third valve 201, and fourth valve 202 are opened, while the fifth valve 301 and sixth valve 302 are closed. The intake air heating system is activated, and the heat medium water flows into the heat exchanger 12. Heated by the flue gas, the water forms steam, which then flows into the generator 14. The steam from the generator 14 flows through the water heat exchanger 17, the throttle valve 16, and the air heat exchanger 15 before entering the absorber 18, where it is absorbed and converted into a dilute solution. After releasing latent heat in the generator 14, the heat medium steam becomes liquid water and flows back to the heat exchanger 12 to continue absorbing heat. Simultaneously, medium-temperature hot water is generated in the water heat exchanger 17, which flows into the air intake heat exchanger 22 to heat the ambient air. The cooled circulating water flows back to the water heat exchanger 17 to absorb heat. The heated ambient air then flows into the gas turbine unit, where it is heated and pressurized, improving the efficiency of the combined cycle. Valves are provided between the first tee 401 and the third tee 402, and between the second tee 501 and the fourth tee 502. The valves are closed during winter operation.

[0039] Reference Figure 2 , Performance comparison of gas turbine before and after transformation, P g —Gas turbine power generation, η g - Gas turbine power generation efficiency. Before the transformation, the power generation and power generation efficiency of the gas turbine 1 deteriorated seriously with the increase of ambient temperature. However, when the ambient temperature rises in summer, the power generation and power generation efficiency of the gas turbine 1 after the transformation using this solution can remain relatively stable. Figure 3 , Performance comparison of gas-steam combined cycle before and after transformation, P tot —Combined cycle power generation, η tot — Combined cycle power generation efficiency; Before the transformation, the total power generation and power generation efficiency of the gas-steam combined cycle gradually deteriorated with the increase of ambient temperature. After the transformation of the scheme of the present invention, the total power generation of the cycle remained basically stable when the ambient temperature changed.

[0040] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A precise heat extraction combined cycle air intake cooling and heating circulation system, characterized by: It comprises a gas turbine (1), wherein the outlet end of the gas turbine (1) is connected to a flue gas duct, and the end of the flue gas duct is connected to a chimney (10); A low-temperature economizer (11), a high-temperature economizer (5), a steam generator (6) and a superheater (7) are sequentially arranged in the flue gas duct, and the low-temperature economizer (11), the high-temperature economizer (5), the steam generator (6) and the superheater (7) are sequentially connected end to end, and a power generation component is provided between the low-temperature economizer (11) and the superheater (7); A heat exchanger (12) is provided between the low-temperature economizer (11) and the high-temperature economizer (5), and the heat exchanger (12) is connected to a temperature regulating component; The temperature regulating assembly includes a generator (14), the heat extractor (12) is connected to the generator (14) to form a loop, the generator (14) is sequentially connected in series with an air heat exchanger (15), a throttle valve (16), a water heat exchanger (17), and an absorber (18), the absorber (18) is connected to an intermediate heat exchanger (20) to form a loop, the intermediate heat exchanger (20) is connected to the generator (14) to form a loop, the water heat exchanger (17) is connected to an air intake heat exchanger (22) to form a loop, and the air intake heat exchanger (22) is located at the air intake end of the gas turbine (1); The power generation assembly comprises a steam turbine (2), a condenser (3) and a condensate pump (4) connected in series in sequence, wherein the air inlet end of the steam turbine (2) is connected to the superheater (7), the liquid outlet end of the condensate pump (4) is connected to the low-temperature economizer (11), and a cooling tower (9) and a circulating water pump (8) are connected in series between the water outlet end and the return water end of the condenser (3).

2. The precise heat extraction combined cycle intake air cooling and heating circulation system according to claim 1, characterized in that: The pipeline between the generator (14) and the air heat exchanger (15) is sequentially connected in series with a first tee (401), a sixth valve (302) and a second tee (501); the pipeline between the water heat exchanger (17) and the absorber (18) is sequentially connected in series with a third tee (402), a fifth valve (301) and a fourth tee (502); the first tee (401) is connected to the third tee (402), and the second tee (501) is connected to the fourth tee (502).

3. The precise heat extraction combined cycle intake air cooling and heating circulation system according to claim 1, characterized in that: A third valve (201) is provided on the liquid inlet pipeline between the water heat exchanger (17) and the air intake heat exchanger (22), and a second booster pump (21) and a fourth valve (202) are provided on the liquid return pipeline between the water heat exchanger (17) and the air intake heat exchanger (22).

4. The precise heat extraction combined cycle intake air cooling and heating circulation system according to claim 1, characterized in that: A solution pump (19) is provided on the liquid return pipeline between the absorber (18) and the intermediate heat exchanger (20).

5. The precise heat extraction combined cycle intake air cooling and heating circulation system according to claim 1, characterized in that: A first valve (101) is provided on the liquid inlet pipeline between the heat extractor (12) and the generator (14), and a first booster pump (13) and a second valve (102) are provided on the liquid return pipeline between the heat extractor (12) and the generator (14).

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