Gas turbine cooling system adopting parallel steam pocket coolers and control method of gas turbine cooling system

Abstract

The invention discloses a gas turbine cooling system adopting parallel steam pocket coolers and a control method of the gas turbine cooling system, and belongs to the technical field of gas turbine energy-saving transformation. A natural gas input pipeline is communicated with an inlet of a combustion chamber through a heat absorption side of a natural gas preheater, and an outlet of a gas compressor is communicated with the inlet of the combustion chamber; a first extraction opening of the gas compressor is communicated with an inlet of the turbine through a third electric valve and the heat release side of the natural gas preheater, a second extraction opening of the gas compressor is divided into three paths, the first path is communicated with the inlet of the turbine through a fourth electric valve and the heat release side of the first turbine cooler, and the second path is communicated with the inlet of the turbine through a third electric valve. The second path communicates with an inlet of the turbine through a fifth electric valve and the heat release side of the second turbine cooler, the third path communicates with the inlet of the turbine through a sixth electric valve, the cooling system and the control method can adapt to different waste heat utilization schemes according to different gas turbine loads, and the flexibility is high.

Description

Technical Field

[0001] The invention belongs to the technical field of energy-saving transformation of gas turbines, and relates to a gas turbine cooling system adopting a parallel-type steam drum cooler and a control method thereof. Background Art

[0002] During the operation of a gas turbine system, it is necessary to adapt a waste heat utilization scheme to effectively improve the thermal utilization rate of the gas turbine system.

[0003] Publication No. CN113530677A discloses a natural gas combined cycle power generation system and method with a pre-positioned fuel cell, including a high-temperature fuel cell, a combustion chamber, a turbine of a gas turbine, a waste heat boiler, and a steam turbine connected in sequence; the input end of the high-temperature fuel cell is connected to a natural gas pipeline. Natural gas enters the high-temperature fuel cell as fuel gas for power generation. The fuel gas at the outlet of the high-temperature fuel cell is sent to the combustion chamber. The fuel gas burns in the combustion chamber to generate high-temperature flue gas, which is sent to the turbine of the gas turbine for power generation. The high-temperature flue gas at the outlet of the turbine is sent to the waste heat boiler, and the steam generated by the waste heat boiler is sent to the steam turbine for power generation.

[0004] However, in the prior art, when recovering the waste heat of a gas turbine system, most use a single waste heat boiler for heat recovery, resulting in a low heat recovery efficiency. At the same time, different waste heat utilization schemes cannot be adapted to different gas turbine loads, and the flexibility is poor. Summary of the Invention

[0005] The purpose of the invention is to overcome the above-mentioned disadvantages of the prior art, and provide a gas turbine cooling system adopting a parallel-type steam drum cooler and a control method thereof. The cooling system and the control method can adapt different waste heat utilization schemes to different gas turbine loads, and have high flexibility.

[0006] To achieve the above purpose, the invention discloses a gas turbine cooling system adopting a parallel-type steam drum cooler, including a natural gas input pipeline, a natural gas preheater, a combustion chamber, a compressor, and a turbine;

[0007] The natural gas input pipeline is connected to the inlet of the combustion chamber through the heat absorption side of the natural gas preheater. The outlet of the compressor is connected to the inlet of the combustion chamber. The first air extraction port of the compressor is connected to the inlet of the turbine through a third electric valve and the heat release side of the natural gas preheater. The second air extraction port of the compressor is divided into three paths. Among them, the first path is connected to the inlet of the turbine through a fourth electric valve and the heat release side of the first turbine cooler. The second path is connected to the inlet of the turbine through a fifth electric valve and the heat release side of the second turbine cooler. The third path is connected to the inlet of the turbine through a sixth electric valve.

[0008] Furthermore, it also includes a waste heat boiler, and the flue gas outlet of the turbine is connected to the flue gas inlet of the waste heat boiler.

[0009] Furthermore, it also includes a steam turbine, a condenser and a condensate pump;

[0010] The main steam outlet of the waste heat boiler is connected to the inlet of the steam turbine, and the exhaust gas outlet of the steam turbine is connected to the water inlet of the waste heat boiler through the condenser and the condensate pump.

[0011] Furthermore, the outlet of the medium and low pressure economizer of the waste heat boiler is divided into two paths, one of which is connected to the heat absorption side inlet of the first turbine cooler through the first electric valve, and the second is connected to the heat absorption side inlet of the second turbine cooler through the second electric valve. The heat absorption side outlet of the first turbine cooler is divided into two paths, one of which is connected to the medium pressure economizer in the waste heat boiler through the eighth electric valve, and the other is connected to the heat absorption side inlet of the second turbine cooler through the seventh electric valve.

[0012] Furthermore, the first electric valve is connected to the heat absorption side inlet of the first turbine cooler via a small-flow medium-pressure water supply pump.

[0013] Furthermore, the heat absorption side outlet of the second turbine cooler is divided into two paths, one of which is connected to the medium-pressure steam drum in the waste heat boiler through the eleventh electric valve, and the other is connected to the low-pressure steam drum in the waste heat boiler through the tenth electric valve.

[0014] Furthermore, it also includes a first generator, and the turbine, compressor and the first generator are coaxially arranged.

[0015] Furthermore, it also includes a second generator, and the steam turbine is connected to the driving shaft of the second generator.

[0016] Furthermore, it also includes a control system, which is connected to the first electric valve, the second electric valve, the third electric valve, the fourth electric valve, the fifth electric valve, the sixth electric valve, the seventh electric valve, the eighth electric valve, the ninth electric valve, the tenth electric valve, the eleventh electric valve, the compressor, the condensate pump and the small-flow medium-pressure feed water pump.

[0017] The present invention discloses a control method for a combustion engine cooling system using a parallel drum cooler, comprising:

[0018] When the first turbine cooler operates normally and the combined cycle unit is at medium or low load, the first electric valve and the eighth electric valve are controlled to open, and the second electric valve is controlled to close. The low-pressure feed water is pressurized by the small-flow medium-pressure feed water pump to form medium-pressure feed water, which flows to the first turbine cooler to exchange heat with the compressed air output by the compressor. At this time, the third electric valve, the fourth electric valve and the sixth electric valve are controlled to open. By adjusting the opening of the sixth electric valve, the mixed air reaches the target temperature for cooling the turbine blades. After the medium-pressure feed water is heated, it is collected into the medium-pressure economizer through the eighth electric valve and finally enters the medium-pressure steam drum;

[0019] When the first turbine cooler is operating normally and the combined cycle unit is at high load, the temperature of the compressed gas output by the compressor becomes higher. At this time, control the first electric valve, the seventh electric valve and the eleventh electric valve to open, control the second electric valve and the eighth electric valve to close, control the third electric valve, the fourth electric valve, the fifth electric valve and the sixth electric valve to open. The medium-pressure feed water first exchanges heat with the first stream of compressed air output by the compressor in the first turbine cooler, then enters the second turbine cooler through the seventh electric valve to absorb the heat of the second stream of compressed air output by the compressor, and then converges into the medium-pressure steam drum through the eleventh electric valve.

[0020] When the first turbine cooler fails and cannot work, control the second electric valve and the tenth electric valve to open, control the first electric valve, the seventh electric valve, the ninth electric valve and the eleventh electric valve to close, control the third electric valve, the fifth electric valve and the sixth electric valve to open, control the fourth electric valve to close. The low-pressure feed water enters the second turbine cooler to absorb the waste heat of the compressed air and evaporates into low-pressure steam, and then converges into the low-pressure steam drum through the tenth electric valve. When the gas turbine is operating alone, control the second electric valve and the ninth electric valve to open, control the first electric valve, the seventh electric valve, the tenth electric valve and the eleventh electric valve to close, control the third electric valve, the fifth electric valve and the sixth electric valve to open, control the fourth electric valve to close. The low-pressure steam generated by the second turbine cooler enters the auxiliary steam header through the ninth electric valve.

[0021] The further improvement of the present invention lies in:

[0022] The present invention has the following beneficial effects:

[0023] When the gas turbine cooling system with a parallel type steam drum cooler and its control method according to the present invention are specifically operated, a turbine cooler is arranged in parallel near the original turbine cooler to adjust the temperature of the turbine cooling air, and different heat recovery utilization schemes are designed for different gas turbine loads. By adding a turbine cooler, the utilization mode of the waste heat of the compressor extraction is increased. After the transformation of the gas turbine cooling system, the gas turbine can use different cooling modes under different loads, which can effectively improve the combined cycle efficiency and the operation safety of the unit. Specifically, when the first turbine cooler is operating normally, the waste heat of the compressor extraction is transferred to the medium-pressure feed water through the first turbine cooler and the second turbine cooler, and part of the waste heat is transferred to the natural gas through the natural gas preheater. When the first turbine cooler fails or the gas turbine is operating alone, the second turbine cooler is relied on for heat exchange alone to transfer the extraction waste heat to the low-pressure feed water. The present invention has the characteristics of strong operability, flexible operation mode, remarkable energy-saving effect, high operation safety of the unit, etc. Description of the Drawings

[0024] The accompanying drawings forming a part of this invention are used to provide a further understanding of the invention. The schematic embodiments of the invention and their descriptions are used to explain the invention and do not unduly limit the invention. In the drawings:

[0025] Figure 1 It is a structural diagram of the present invention.

[0026] Among them, 1 is the first electric valve, 2 is the second electric valve, 3 is the third electric valve, 4 is the fourth electric valve, 5 is the fifth electric valve, 6 is the sixth electric valve, 7 is the seventh electric valve, 8 is the eighth electric valve, 9 is the ninth electric valve, 10 is the tenth electric valve, 11 is the eleventh electric valve, 12 is the compressor, 13 is the combustion chamber, 14 is the turbine, 15 is the first generator, 16 is the first turbine cooler, 17 is the second turbine cooler, 18 is the steam turbine, 19 is the second generator, 20 is the waste heat boiler, 21 is the condensate pump, 22 is the condenser, 23 is the small flow medium pressure feed water pump, and 24 is the natural gas preheater. Detailed implementation manners

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] In the description of the present invention, it should be understood that the terms "include" and "comprise" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0029] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0030] It should be further understood that the term " / and" as used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present invention generally represents an "or" relationship between the front and rear associated objects.

[0031] It should be understood that although terms such as first, second, and third may be used in the embodiments of the present invention to describe preset ranges and the like, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0032] Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detected (stated condition or event)" may be interpreted as "when determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)".

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the present invention described and shown in the accompanying drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0034] Schematic diagrams of various structures according to the disclosed embodiments of the present invention are shown in the drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures and their relative sizes and positional relationships are merely exemplary, and may actually deviate due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0035] Embodiment 1

[0036] Reference Figure 1, the gas turbine cooling system using a parallel drum cooler according to the present invention includes a first electric valve 1, a second electric valve 2, a third electric valve 3, a fourth electric valve 4, a fifth electric valve 5, a sixth electric valve 6, a seventh electric valve 7, an eighth electric valve 8, a ninth electric valve 9, a tenth electric valve 10, an eleventh electric valve 11, a compressor 12, a combustion chamber 13, a turbine 14, a first generator 15, a first turbine cooler 16, a second turbine cooler 17, a steam turbine 18, a second generator 19, a waste heat boiler 20, a condensate pump 21, a condenser 22, a small flow medium pressure feed water pump 23, and a natural gas preheater 24;

[0037] The natural gas input pipeline is connected to the inlet of the combustion chamber 13 through the heat absorption side of the natural gas preheater 24, the outlet of the compressor 12 is connected to the inlet of the combustion chamber 13, the first extraction port of the compressor 12 is connected to the inlet of the turbine 14 through the heat release side of the natural gas preheater 24, and the second extraction port of the compressor 12 is divided into three paths. Among them, the first path is connected to the inlet of the turbine 14 through the fourth electric valve 4 and the heat release side of the first turbine cooler 16, the second path is connected to the inlet of the turbine 14 through the fifth electric valve 5 and the heat release side of the second turbine cooler 17, and the third path is connected to the inlet of the turbine 14 through the sixth electric valve 6;

[0038] The flue gas outlet of the turbine 14 is connected to the flue gas inlet of the waste heat boiler 20, the main steam outlet of the waste heat boiler 20 is connected to the inlet of the steam turbine 18, the exhaust gas outlet of the steam turbine 18 is connected to the water inlet of the waste heat boiler 20 through the condenser 22 and the condensate pump 21. The outlet of the medium and low pressure economizer of the waste heat boiler 20 is divided into two paths. One path is connected to the inlet of the heat absorption side of the first turbine cooler 16 through the first electric valve 1 and the small flow medium pressure feed water pump 23, and the second path is connected to the inlet of the heat absorption side of the second turbine cooler 17 through the second electric valve 2. The outlet of the heat absorption side of the first turbine cooler 16 is divided into two paths. One path is connected to the medium pressure economizer in the waste heat boiler 20 through the eighth electric valve 8, and the other path is connected to the inlet of the heat absorption side of the second turbine cooler 17 through the seventh electric valve 7. The outlet of the heat absorption side of the second turbine cooler 17 is divided into two paths. One path is connected to the medium pressure drum in the waste heat boiler 20 through the eleventh electric valve 11, and the other path is connected to the low pressure drum in the waste heat boiler 20 through the tenth electric valve 10.

[0039] The turbine 14, the compressor 12, and the first generator 15 are coaxially arranged; the steam turbine 18 is connected to the drive shaft of the second generator 19.

[0040] This embodiment further includes a control system, which is connected to the first electric valve 1, the second electric valve 2, the third electric valve 3, the fourth electric valve 4, the fifth electric valve 5, the sixth electric valve 6, the seventh electric valve 7, the eighth electric valve 8, the ninth electric valve 9, the tenth electric valve 10, the eleventh electric valve 11, the compressor 12, the condensate pump 21, and the small-flow medium-pressure feed water pump 23. During operation, according to the actual control situation, the control system controls the first electric valve 1, the second electric valve 2, the third electric valve 3, the fourth electric valve 4, the fifth electric valve 5, the sixth electric valve 6, the seventh electric valve 7, the eighth electric valve 8, the ninth electric valve 9, the tenth electric valve 10, the eleventh electric valve 11, the compressor 12, the condensate pump 21, and the small-flow medium-pressure feed water pump 23.

[0041] During operation, the air output by the compressor 12 enters the combustion chamber 13. The natural gas output from the natural gas input pipeline enters the combustion chamber 13 after being preheated by the natural gas preheater 24 and burns to generate high-temperature flue gas. The high-temperature flue gas enters the turbine 14 to do work. The turbine 15 drives the first generator 15 to generate electricity. The flue gas discharged from the turbine 15 enters the waste heat boiler 20. The gas extracted from the first extraction port of the compressor 12 enters the heat release side of the natural gas preheater 24 to release heat, and then enters the turbine 14. The gas extracted from the second extraction port of the compressor 12 is divided into two paths. One path enters the turbine 14 through the first turbine cooler 16, another path enters the turbine 14 through the second turbine cooler 17, and the third path directly enters the turbine 14.

[0042] The main steam output by the waste heat boiler 20 enters the steam turbine 18 to do work. The exhaust gas discharged from the steam turbine 18 enters the waste heat boiler 20 through the condenser 22 and the condensate pump 21. The steam output by the low-pressure economizer in the waste heat boiler 20 is divided into two paths. One path enters the first turbine cooler 16 to absorb heat, and then enters the medium-pressure economizer and the second turbine cooler 17 in the waste heat boiler 20. The second path enters the second turbine cooler 17 to absorb heat. The steam output from the heat absorption side of the second turbine cooler 17 is divided into two paths. One path enters the medium-pressure steam drum in the waste heat boiler 20, and the other path enters the low-pressure steam drum in the waste heat boiler 20.

[0043] Embodiment 2

[0044] The present invention discloses a control method for a gas turbine cooling system using a parallel drum cooler. The gas turbine cooling system using the parallel drum cooler includes a first electric valve 1, a second electric valve 2, a third electric valve 3, a fourth electric valve 4, a fifth electric valve 5, a sixth electric valve 6, a seventh electric valve 7, an eighth electric valve 8, a ninth electric valve 9, a tenth electric valve 10, an eleventh electric valve 11, a compressor 12, a combustion chamber 13, a turbine 14, a first generator 15, a first turbine cooler 16, a second turbine cooler 17, a steam turbine 18, a second generator 19, a waste heat boiler 20, a condensate pump 21, a condenser 22, a small flow medium pressure feed water pump 23 and a natural gas preheater 24. The specific connection method is as shown in the first embodiment.

[0045] Specifically, the control method of the gas turbine cooling system using the parallel drum cooler comprises the following steps:

[0046] After the air is compressed by the compressor 12, the compressed air and natural gas are burned in the combustion chamber 13 to generate high-temperature flue gas, which enters the turbine 14 to expand and do work. The exhaust gas of the turbine 14 enters the waste heat boiler 20 to heat the boiler feed water to form main steam with different pressure parameters, among which the main steam enters the steam turbine 18 to expand and do work. The exhaust steam of the steam turbine 18 enters the condenser 22 to form condensate, which is then pressurized by the condensate pump 21 to the waste heat boiler 20 to form a steam-water circulation, and the heat of the condenser 22 is taken away by the circulating water.

[0047] The first turbine cooler 16 and the second turbine cooler 17 are air / water heat exchangers. The water output from the low-pressure economizer enters the first turbine cooler 16 and the second turbine cooler 17. The modified gas turbine cooling system has a more flexible working mode than before the modification. The energy level of waste heat is different when the gas turbine load is different. According to the principle of energy cascade utilization, waste heat utilization is divided into two different ways:

[0048] When the first turbine cooler 16 operates normally and the combined cycle unit is at medium or low load, the first electric valve 1 and the eighth electric valve 8 are controlled to open, and the second electric valve 2 is controlled to close. The low-pressure feed water is pressurized by the small-flow medium-pressure feed water pump 23 to form medium-pressure feed water, which flows to the first turbine cooler 16 for heat exchange with the compressed air output by the compressor 12. At this time, the third electric valve 3, the fourth electric valve 4 and the sixth electric valve 6 are controlled to open. By adjusting the opening of the sixth electric valve 6, the mixed air reaches the target temperature for cooling the blades of the turbine 14. After the medium-pressure feed water is heated, it is merged into the medium-pressure economizer through the eighth electric valve 8 and finally enters the medium-pressure steam drum.

[0049] When the first turbine cooler 16 operates normally and the combined cycle unit is under high load, the temperature of the compressed gas output by the compressor 12 becomes high. At this time, the first electric valve 1, the seventh electric valve 7 and the eleventh electric valve 11 are controlled to be opened, the second electric valve 2 and the eighth electric valve 8 are controlled to be closed, and the third electric valve 3, the fourth electric valve 4, the fifth electric valve 5 and the sixth electric valve 6 are controlled to be opened. The medium-pressure feed water first exchanges heat with the compressed air output by the first compressor 12 in the first turbine cooler 16, and then enters the second turbine cooler 17 through the seventh electric valve 7 to absorb the heat of the compressed air output by the second compressor 12, and then flows into the medium-pressure steam drum through the eleventh electric valve 11. It should be noted that the sixth electric valve 6 is a bypass regulating valve, and the seventh electric valve 7 is a check valve.

[0050] When the first turbine cooler 16 fails to work, the second electric valve 2 and the tenth electric valve 10 are controlled to open, the first electric valve 1, the seventh electric valve 7, the ninth electric valve 9 and the eleventh electric valve 11 are controlled to close, the third electric valve 3, the fifth electric valve 5 and the sixth electric valve 6 are controlled to open, and the fourth electric valve 4 is controlled to close. The low-pressure feed water enters the second turbine cooler 17 to absorb the waste heat of the compressed air and evaporate into low-pressure steam, and then flows into the low-pressure steam drum through the tenth electric valve 10. Or when the combustion engine is in single-unit operation, the second electric valve 2 and the ninth electric valve 9 are controlled to open, the first electric valve 1, the seventh electric valve 7, the tenth electric valve 10 and the eleventh electric valve 11 are controlled to close, the third electric valve 3, the fifth electric valve 5 and the sixth electric valve 6 are controlled to open, and the fourth electric valve 4 is controlled to close, and the low-pressure steam generated by the second turbine cooler 17 enters the auxiliary steam header through the ninth electric valve 9 to provide auxiliary steam for the unit.

[0051] It should be noted that the present invention arranges a drum cooler in parallel near the original turbine cooler to adjust the turbine cooling air temperature, and designs different adaptive waste heat utilization schemes for different gas turbine loads. After the gas turbine cooling system is modified, the gas turbine can use different cooling modes under different operating modes and different loads, which effectively improves the combined cycle efficiency and the safety of unit operation. The present invention has the characteristics of strong operability, flexible operating mode, significant energy-saving effect, and high unit operation safety.

[0052] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0053] It should be understood that the present invention is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

[0054] As described above, these are only the preferred embodiments of the present invention and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent structural changes made to the above embodiments based on the technical essence of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A gas turbine cooling system using a parallel drum cooler, characterized in that: It includes a natural gas input pipeline, a natural gas preheater (24), a combustion chamber (13), a compressor (12) and a turbine (14); The natural gas input pipeline is connected to the inlet of the combustion chamber (13) through the heat absorption side of the natural gas preheater (24), the outlet of the compressor (12) is connected to the inlet of the combustion chamber (13), the first air extraction port of the compressor (12) is connected to the inlet of the turbine (14) through the third electric valve (3) and the heat release side of the natural gas preheater (24), and the second air extraction port of the compressor (12) is divided into three routes, wherein the first route is connected to the inlet of the turbine (14) through the fourth electric valve (4) and the heat release side of the first turbine cooler (16), the second route is connected to the inlet of the turbine (14) through the fifth electric valve (5) and the heat release side of the second turbine cooler (17), and the third route is connected to the inlet of the turbine (14) through the sixth electric valve (6).

2. The combustion engine cooling system using a parallel drum cooler according to claim 1, characterized in that: It also includes a waste heat boiler (20), and the flue gas outlet of the turbine (14) is connected to the flue gas inlet of the waste heat boiler (20).

3. The combustion engine cooling system using a parallel drum cooler according to claim 2, characterized in that: It also includes a steam turbine (18), a condenser (22) and a condensate pump (21); The main steam outlet of the waste heat boiler (20) is connected to the inlet of the steam turbine (18), and the exhaust gas outlet of the steam turbine (18) is connected to the water inlet of the waste heat boiler (20) via the condenser (22) and the condensate pump (21).

4. The combustion engine cooling system using a parallel drum cooler according to claim 3 is characterized in that: The outlet of the medium-pressure economizer of the waste heat boiler (20) is divided into two paths, one of which is connected to the heat absorption side inlet of the first turbine cooler (16) through the first electric valve (1), and the second is connected to the heat absorption side inlet of the second turbine cooler (17) through the second electric valve (2). The heat absorption side outlet of the first turbine cooler (16) is divided into two paths, one of which is connected to the medium-pressure economizer in the waste heat boiler (20) through the eighth electric valve (8), and the other is connected to the heat absorption side inlet of the second turbine cooler (17) through the seventh electric valve (7).

5. The combustion engine cooling system using a parallel drum cooler according to claim 4, characterized in that: The first electric valve (1) is connected to the heat absorption side inlet of the first turbine cooler (16) via a small flow medium pressure water supply pump (23).

6. The combustion engine cooling system using a parallel drum cooler according to claim 5, characterized in that: The heat absorption side outlet of the second turbine cooler (17) is divided into two paths, one of which is connected to the medium-pressure steam drum in the waste heat boiler (20) through the eleventh electric valve (11), and the other is connected to the low-pressure steam drum in the waste heat boiler (20) through the tenth electric valve (10).

7. The combustion engine cooling system using a parallel drum cooler according to claim 1, characterized in that: It also includes a first generator (15), and the turbine (14), the compressor (12) and the first generator (15) are coaxially arranged.

8. The combustion engine cooling system using a parallel drum cooler according to claim 3, characterized in that: It also includes a second generator (19), and the steam turbine (18) is connected to the driving shaft of the second generator (19).

9. The combustion engine cooling system using a parallel drum cooler according to claim 6, characterized in that: The invention also includes a control system, which is connected to the first electric valve (1), the second electric valve (2), the third electric valve (3), the fourth electric valve (4), the fifth electric valve (5), the sixth electric valve (6), the seventh electric valve (7), the eighth electric valve (8), the ninth electric valve (9), the tenth electric valve (10), the eleventh electric valve (11), the compressor (12), the condensate pump (21) and the small-flow medium-pressure feed water pump (23).

10. A control method for a combustion engine cooling system using a parallel drum cooler as claimed in claim 6, characterized in that: include: When the first turbine cooler (16) operates normally and the combined cycle unit is at medium or low load, the first electric valve (1) and the eighth electric valve (8) are controlled to open, and the second electric valve (2) is controlled to close. The low-pressure feed water is pressurized by the small-flow medium-pressure feed water pump (23) to form medium-pressure feed water, which flows into the first turbine cooler (16) to exchange heat with the compressed air output by the compressor (12). At this time, the third electric valve (3), the fourth electric valve (4) and the sixth electric valve (6) are controlled to open. By adjusting the opening of the sixth electric valve (6), the mixed air reaches the target temperature for cooling the turbine (14) blades. After the medium-pressure feed water is heated, it flows into the medium-pressure economizer through the eighth electric valve (8) and finally enters the medium-pressure steam drum; When the first turbine cooler (16) operates normally and the combined cycle unit is under high load, the temperature of the compressed gas output by the compressor (12) becomes high. At this time, the first electric valve (1), the seventh electric valve (7) and the eleventh electric valve (11) are controlled to be opened, the second electric valve (2) and the eighth electric valve (8) are controlled to be closed, and the third electric valve (3), the fourth electric valve (4), the fifth electric valve (5) and the sixth electric valve (6) are controlled to be opened. The medium-pressure feed water first exchanges heat with the compressed air output by the first compressor (12) in the first turbine cooler (16), then enters the second turbine cooler (17) through the seventh electric valve (7) to absorb the heat of the compressed air output by the second compressor (12), and then flows into the medium-pressure steam drum through the eleventh electric valve (11); When the first turbine cooler (16) fails to operate, the second electric valve (2) and the tenth electric valve (10) are controlled to open, the first electric valve (1), the seventh electric valve (7), the ninth electric valve (9) and the eleventh electric valve (11) are controlled to close, the third electric valve (3), the fifth electric valve (5) and the sixth electric valve (6) are controlled to open, and the fourth electric valve (4) is controlled to close, and the low-pressure feed water enters the second turbine cooler (17) to absorb the waste heat of the compressed air and evaporate into low-pressure steam, and then passes through the first electric valve (17) to evaporate the waste heat of the compressed air. The second electric valve (2) and the ninth electric valve (9) are controlled to be opened, the first electric valve (1), the seventh electric valve (7), the tenth electric valve (10) and the eleventh electric valve (11) are controlled to be closed, the third electric valve (3), the fifth electric valve (5) and the sixth electric valve (6) are controlled to be opened, the fourth electric valve (4) is controlled to be closed, and the low-pressure steam generated by the second turbine cooler (17) enters the auxiliary steam header through the ninth electric valve (9).

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