System and method for shortening starting time of unit by using waste heat of gas turbine cooling system

Abstract

The invention discloses a system and a method for shortening the starting time of a unit by using waste heat of a gas turbine cooling system, and belongs to the technical field of energy-saving transformation of gas turbines, and an outlet of a low-temperature economizer in a waste heat boiler is divided into two paths, one path is communicated with the heat release side of a natural gas preheater through a first electric valve, a small-flow medium-pressure water feeding pump and the heat absorption side of a first turbine cooler; the other path is communicated with a heat absorption side inlet of a second turbine cooler through a second electric valve, a heat absorption side outlet of the second turbine cooler is communicated with an inlet of an electric heater, an outlet of the auxiliary steam header is communicated with an inlet of the electric heater through a third electric valve, and an outlet of the electric heater is communicated with an outlet of the intermediate-pressure cylinder through an intermediate-pressure cylinder pre-warming valve; according to the system and the method, the starting time of a unit can be shortened, and consumption of extra natural gas is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of energy-saving transformation of gas turbines, and relates to a system and method for shortening the start-up time of a unit by utilizing waste heat of a gas turbine cooling system. Background Art

[0002] In a gas turbine combined with a steam turbine power generation system, after the gas turbine is started with load, the steam turbine can be directly connected to the grid to increase the load only after the main steam and reheat steam meet the start-up requirements.

[0003] Publication No. CN110847984A discloses a supercritical carbon dioxide cycle coal-fired power generation system with integrated low-temperature waste heat recovery and an operation method, comprising a two-stage main compressor, an interstage cooler, a recompressor, a precooler, a three-stage regenerator, a boiler, a high-pressure turbine, a medium-pressure turbine, and a low-pressure turbine; a superheated gas cooling wall and a primary reheater are arranged in the boiler furnace to jointly bear the furnace radiation heat load to prevent the superheated supercritical carbon dioxide from overheating; a portion of the supercritical carbon dioxide working medium is diverted from the outlet of the medium-temperature regenerator to enter the medium-temperature economizer in the vertical flue at the rear of the boiler to absorb the heat of the high-temperature flue gas, and a portion of the supercritical carbon dioxide working medium is diverted from the outlet of the second-stage main compressor to enter the low-temperature economizer in the diversion flue at the tail of the boiler to absorb the heat of the low-temperature flue gas.

[0004] The above existing technologies only recover low-temperature waste heat. However, during the startup of the steam turbine, the steam turbine needs to be preheated. The preheating time of the steam turbine is relatively long when the gas turbine is started, which in turn prolongs the startup time of the unit and consumes additional natural gas. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a system and method for shortening the startup time of the unit by utilizing the waste heat of the gas turbine cooling system. The system and method can shorten the startup time of the unit and avoid consuming additional natural gas.

[0006] To achieve the above object, the present invention discloses a system for shortening the start-up time of a unit by utilizing waste heat from a gas turbine cooling system, comprising a waste heat boiler, a natural gas preheater, a second turbine cooler, an electric heater, an auxiliary steam header, a medium-pressure cylinder and a high-pressure cylinder;

[0007] The outlet of the low-temperature economizer in the waste heat boiler is divided into two routes, one of which is connected to the heat release side of the natural gas preheater through the first electric valve, a small-flow medium-pressure feed water pump, and the heat absorption side of the first turbine cooler; the other 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 second turbine cooler is connected to the inlet of the electric heater, the outlet of the auxiliary steam manifold is connected to the inlet of the electric heater through the third electric valve, the outlet of the electric heater is connected to the outlet of the medium-pressure cylinder through the medium-pressure cylinder preheating valve, and the outlet of the electric heater is connected to the outlet of the high-pressure cylinder through the high-pressure cylinder back-warming valve.

[0008] Furthermore, it also includes a natural gas input pipeline, a combustion chamber, a turbine, and a compressor;

[0009] 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 combustion chamber is connected to the inlet of the turbine. The outlet of the compressor is connected to the inlet of the combustion chamber. The 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 the 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 the 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 the sixth electric valve. The flue gas outlet of the turbine is connected to the flue gas inlet of the waste heat boiler.

[0010] Furthermore, the main steam outlet of the waste heat boiler is connected to the inlet of the high-pressure cylinder through the high-pressure main steam valve. The outlet of the high-pressure cylinder is connected to the reheat side inlet of the waste heat boiler through the high-pressure exhaust check valve. The reheat side outlet of the waste heat boiler is connected to the inlet of the intermediate-pressure cylinder through the intermediate-pressure main steam valve. The outlet of the intermediate-pressure cylinder is connected to the inlet of the low-pressure cylinder through the low-pressure main steam valve. The outlet of the low-pressure cylinder is connected to the feed water inlet of the waste heat boiler through the condenser and the condensate pump.

[0011] Furthermore, the main steam outlet of the waste heat boiler and the reheat side inlet are connected through a high bypass hydraulic valve.

[0012] Furthermore, the superheated steam outlet of the waste heat boiler is connected to the inlet of the condenser through the intermediate bypass hydraulic valve.

[0013] Furthermore, the outlet of the intermediate-pressure cylinder is connected to the inlet of the condenser through the low bypass hydraulic valve.

[0014] Furthermore, a low-pressure cylinder drain valve is provided at the drain outlet of the low-pressure cylinder, an intermediate-pressure cylinder drain valve is provided at the drain port of the intermediate-pressure cylinder, and a high-pressure cylinder drain valve is provided at the drain port of the high-pressure cylinder.

[0015] Furthermore, the compressor, the turbine, and the first generator are arranged coaxially.

[0016] Furthermore, the low-pressure cylinder, the intermediate-pressure cylinder, the high-pressure cylinder, and the second generator are arranged coaxially.

[0017] The present invention discloses a method for shortening the startup time of a unit by utilizing the waste heat of a gas turbine cooling system, including the following steps:

[0018] Open the second electric valve, the fifth electric valve and the sixth electric valve. The feed water output by the low-pressure economizer absorbs heat and evaporates into superheated steam in the second turbine cooler. Open the third electric valve and supplement the steam volume through the auxiliary steam header to ensure the cylinder preheating requirement. At the initial stage of the gas turbine startup, when the steam temperature is insufficient, turn on the electric heater. After the gas turbine starts up, open the high-pressure bypass hydraulic valve, the intermediate-pressure bypass hydraulic valve and the low-pressure bypass hydraulic valve, and send the steam that does not reach the steam turbine rotation starting parameters into the condenser. Open the high-pressure cylinder reverse warming valve, the intermediate-pressure cylinder preheating valve, the high-pressure cylinder drain valve, the intermediate-pressure cylinder drain valve and the low-pressure cylinder drain valve in advance. Confirm that the high-pressure main steam valve and the intermediate-pressure main steam valve are closed, and carry out reverse warming of the high-pressure cylinder and the intermediate-pressure cylinder, so that the warming steam enters the high-pressure cylinder and the intermediate-pressure cylinder. The drain water discharged from the high-pressure cylinder, the intermediate-pressure cylinder and the low-pressure cylinder enters the condenser. When the cylinder body of the high-pressure cylinder and the intermediate-pressure cylinder is preheated to the preset temperature, stop the reverse warming and close the high-pressure cylinder reverse warming valve and the intermediate-pressure cylinder preheating valve. Wait until the superheated steam parameters generated by the waste heat boiler meet the steam turbine rotation starting parameters, then open the high-pressure main steam valve and the intermediate-pressure main steam valve to carry out warm-state startup, and then synchronize to the grid. As the load increases, gradually close the high-pressure bypass hydraulic valve, the intermediate-pressure bypass hydraulic valve and the low-pressure bypass hydraulic valve.

[0019] The present invention has the following beneficial effects:

[0020] When the system and method for shortening the unit startup time by using the waste heat of the gas turbine cooling system according to the present invention are specifically operated, a second turbine cooler is arranged in parallel near the original turbine cooler for producing low-pressure steam used for steam turbine preheating. When waiting for the gas turbine to start up again, the steam turbine can be preheated in advance. In this way, after the gas turbine starts up and takes load, as long as the main steam and the reheated steam meet the rotation starting requirements, the steam turbine can directly synchronize to the grid and increase the load, reducing the consumption of natural gas. After the preheating is completed, it is switched to the common use mode of the double turbine coolers to recover the waste heat of the extraction steam. After the transformation, the performance of the combined cycle can be effectively improved, and it has the characteristics of strong operability in use, flexible operation mode and remarkable energy-saving effect. Description of the Drawings

[0021] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0022] Figure 1 is the structural diagram of the present invention.

[0023] Among them, 1 is a compressor, 2 is a combustion chamber, 3 is a natural gas preheater, 4 is a turbine, 5 is a first generator, 6 is a small-flow medium-pressure feed water pump, 7 is a first turbine cooler 7, 8 is a second turbine cooler, 9 is an electric heater, 10 is a low-pressure cylinder, 11 is a medium-pressure cylinder, 12 is a high-pressure cylinder, 13 is a second generator, 14 is a waste heat boiler, 15 is a condenser, 16 is a condensate pump, 17 is a high-pressure main steam valve, 18 is a high-pressure cylinder drain valve, 19 is a medium-pressure main steam valve, 20 is a medium-pressure cylinder drain valve, 21 is a low-pressure main steam valve, 22 is a low-pressure cylinder drain valve, 23 is a medium-pressure cylinder prewarming valve, 24 is a low bypass hydraulic valve, 25 is an auxiliary steam header, 26 is a high-pressure exhaust check valve, 27 is a medium bypass hydraulic valve, 28 is a high bypass hydraulic valve, 29 is a first electric valve, 30 is a second electric valve, 31 is a third electric valve, 32 is a fourth electric valve, 33 is a fifth electric valve, 34 is a sixth electric valve, 35 is a high-pressure cylinder reverse warming valve. Specific embodiments

[0024] 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 part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] 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.

[0026] 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.

[0027] It should be further understood that the term " / and" 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 related listed items, and includes these combinations. For example, A and / or B can represent: 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 related objects.

[0028] It should be understood that although the terms first, second, third, etc. 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.

[0029] Depending on the context, the word "if" as used herein can 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)" can be interpreted as "when determined" or "in response to determining" or "when detected (stated condition or event)" or "in response to detecting (stated condition or event)".

[0030] 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. Generally, the components of the present invention described and shown in the accompanying drawings here 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 fall within the scope of protection of the present invention.

[0031] Various structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the drawings. These figures are not drawn to scale, where some details are enlarged for the purpose of clear expression, 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 only 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.

[0032] Embodiment 1

[0033] Reference Figure 1, the system for shortening the startup time of the unit by utilizing the waste heat of the gas turbine cooling system of the present invention includes a compressor 1, a combustion chamber 2, a natural gas preheater 3, a turbine 4, a first generator 5, a small-flow medium-pressure feed water pump 6, a first turbine cooler 7, a second turbine cooler 8, an electric heater 9, a low-pressure cylinder 10, a medium-pressure cylinder 11, a high-pressure cylinder 12, a second generator 13, a waste heat boiler 14, a condenser 15, a condensate pump 16, a high-pressure main steam valve 17, a high-pressure cylinder drain valve 18, a medium-pressure main steam valve 19, a medium-pressure cylinder drain valve 20, a low-pressure main steam valve 21, a low-pressure cylinder drain valve 22, a medium-pressure cylinder prewarming valve 23, a low bypass hydraulic valve 24, an auxiliary steam header 25, a high-pressure exhaust check valve 26, a medium bypass hydraulic valve 27, a high bypass hydraulic valve 28, a first electric valve 29, a second electric valve 30, a third electric valve 31, a fourth electric valve 32, a fifth electric valve 33, a sixth electric valve 34, and a high-pressure cylinder reverse warming valve 35;

[0034] The natural gas input pipeline is connected to the inlet of the combustion chamber 2 through the heat absorption side of the natural gas preheater 3, the outlet of the combustion chamber 2 is connected to the inlet of the turbine 4, the outlet of the compressor 1 is connected to the inlet of the combustion chamber 2, and the extraction port of the compressor 1 is divided into three paths. Among them, the first path is connected to the inlet of the turbine 4 through the fourth electric valve 32 and the heat release side of the first turbine cooler 7, the second path is connected to the inlet of the turbine 4 through the fifth electric valve 33 and the heat release side of the second turbine cooler 8, the third path is connected to the inlet of the turbine 4 through the sixth electric valve 34, and the flue gas outlet of the turbine 4 is connected to the flue gas inlet of the waste heat boiler 14;

[0035] The main steam outlet of the waste heat boiler 14 is connected to the inlet of the high-pressure cylinder 12 through the high-pressure main steam valve 17, the outlet of the high-pressure cylinder 12 is connected to the reheat side inlet of the waste heat boiler 14 through the high-pressure exhaust check valve 26, the reheat side outlet of the waste heat boiler 14 is connected to the inlet of the medium-pressure cylinder 11 through the medium-pressure main steam valve 19, the outlet of the medium-pressure cylinder 11 is connected to the inlet of the low-pressure cylinder 10 through the low-pressure main steam valve 21, and the outlet of the low-pressure cylinder 10 is connected to the feed water inlet of the waste heat boiler 14 through the condenser 15 and the condensate pump 16.

[0036] The main steam outlet and the reheat side inlet of the waste heat boiler 14 are connected through the high bypass hydraulic valve 28, the superheated steam outlet of the waste heat boiler 14 is connected to the inlet of the condenser 15 through the medium bypass hydraulic valve 27, and the outlet of the medium-pressure cylinder 11 is connected to the inlet of the condenser 15 through the low bypass hydraulic valve 24.

[0037] The outlet of the low- and medium-temperature economizer of the waste heat boiler 14 is divided into two paths. One path is connected to the heat release side of the natural gas preheater 3 through the first electric valve 29, the small-flow medium-pressure feed water pump 6, and the heat absorption side of the first turbine cooler 7. The other path is connected to the inlet of the heat absorption side of the second turbine cooler 8 through the second electric valve 30. The outlet of the heat absorption side of the second turbine cooler 8 is connected to the inlet of the electric heater 9. The outlet of the auxiliary steam header 25 is connected to the inlet of the electric heater 9 through the third electric valve 31. The outlet of the electric heater 9 is connected to the outlet of the intermediate pressure cylinder 11 through the intermediate pressure cylinder prewarming valve 23, and the outlet of the electric heater 9 is connected to the outlet of the high pressure cylinder 12 through the high pressure cylinder warming-up reverse valve 35.

[0038] A low-pressure cylinder drain valve 22 is provided at the drain outlet of the low-pressure cylinder 10, an intermediate pressure cylinder drain valve 20 is provided at the drain port of the intermediate pressure cylinder 11, and a high-pressure cylinder drain valve 18 is provided at the drain port of the high-pressure cylinder 12.

[0039] The compressor 1, the turbine 4, and the first generator 5 are coaxially arranged.

[0040] The low-pressure cylinder 10, the intermediate pressure cylinder 11, the high-pressure cylinder 12, and the second generator 13 are coaxially arranged.

[0041] During operation, the air output by the compressor 1 enters the combustion chamber 2. The natural gas output from the natural gas input pipeline enters the natural gas preheater 3 to absorb heat, and then enters the combustion chamber 2 to burn to generate high-temperature flue gas. The high-temperature flue gas enters the turbine 4 to do work. The flue gas discharged from the turbine 4 enters the waste heat boiler 14. The extraction air of the compressor 1 is divided into three paths. The first path enters the first turbine cooler 7 to release heat, and then enters the turbine 4. The second path enters the second turbine cooler 8 to release heat, and then enters the turbine 4. The third path directly enters the turbine 4.

[0042] The main steam output by the waste heat boiler 14 enters the high-pressure cylinder 12. The exhaust steam of the high-pressure cylinder 12 enters the waste heat boiler 14 for reheating, and then enters the intermediate pressure cylinder 11. The exhaust steam of the high-pressure cylinder 11 enters the low-pressure cylinder 10. The exhaust steam of the low-pressure cylinder 10 enters the condenser 15 for cooling. The condensed water output by the condenser 15 enters the waste heat boiler 14.

[0043] The superheated steam output by the waste heat boiler enters the condenser 15. The exhaust steam of the intermediate pressure cylinder 11 enters the condenser 15. The steam output by the low- and medium-temperature economizer of the waste heat boiler 14 is divided into two paths. One path enters the first turbine cooler 7 to absorb heat and then enters the natural gas preheater to release heat. The other path enters the second turbine cooler 8 to absorb heat and then enters the electric heater 9 for heating. The steam output by the auxiliary steam header 25 enters the electric heater 9 for heating. The steam output by the electric heater 9 is divided into two paths. One path enters the low-pressure cylinder 10, and the other path enters the reheating side of the waste heat boiler 14.

[0044] In addition, according to the actual operation conditions, the high-pressure main steam valve 17, the high-pressure cylinder drain valve 18, the intermediate-pressure main steam valve 19, the intermediate-pressure cylinder drain valve 20, the low-pressure main steam valve 21, the low-pressure cylinder drain valve 22, the intermediate-pressure cylinder prewarming valve 23, the low bypass hydraulic valve 24, the auxiliary steam header 25, the high-pressure exhaust check valve 26, the intermediate bypass hydraulic valve 27, the high bypass hydraulic valve 28, the first electric valve 29, the second electric valve 30, the third electric valve 31, the fourth electric valve 32, the fifth electric valve 33, the sixth electric valve 34 and the high-pressure cylinder reverse warming valve 35 are controlled to meet different operating conditions.

[0045] Embodiment 2

[0046] The present invention discloses a method for shortening the start-up time of a unit by using the waste heat of a gas turbine cooling system. The method for shortening the start-up time of a unit by using the waste heat of a gas turbine cooling system is realized based on the system for shortening the start-up time of a unit by using the waste heat of a gas turbine cooling system. The system for shortening the start-up time of a unit by using the waste heat of a gas turbine cooling system includes a compressor 1, a combustion chamber 2, a natural gas preheater 3, a turbine 4, a first generator 5, a small-flow intermediate-pressure feed water pump 6, a first turbine cooler 7, a second turbine cooler 8, an electric heater 9, a low-pressure cylinder 10, an intermediate-pressure cylinder 11, a high-pressure cylinder 12, a second generator 13, a waste heat boiler 14, a condenser 15, a condensate pump 16, a high-pressure main steam valve 17, a high-pressure cylinder drain valve 18, an intermediate-pressure main steam valve 19, an intermediate-pressure cylinder drain valve 20, a low-pressure main steam valve 21, a low-pressure cylinder drain valve 22, an intermediate-pressure cylinder prewarming valve 23, a low bypass hydraulic valve 24, an auxiliary steam header 25, a high-pressure exhaust check valve 26, an intermediate bypass hydraulic valve 27, a high bypass hydraulic valve 28, a first electric valve 29, a second electric valve 30, a third electric valve 31, a fourth electric valve 32, a fifth electric valve 33, a sixth electric valve 34 and a high-pressure cylinder reverse warming valve 35, and the specific connection mode is as shown in Embodiment 1.

[0047] The method for shortening the start-up time of a unit by using the waste heat of a gas turbine cooling system includes the following steps:

[0048] The compressed air output by the compressor 1 and natural gas are burned in the combustion chamber 2 to generate high-temperature flue gas. The high-temperature flue gas enters the turbine 4 to expand and do work. The exhaust gas of the turbine 4 enters the waste heat boiler 14 to heat the boiler feed water to form main steam with different pressure parameters. The main steam enters the steam turbine unit to expand and do work. The exhaust steam of the steam turbine enters the condenser 15 to form condensate, and then is pumped to the waste heat boiler 14 by the condensate pump 16 to form a steam-water cycle. The heat of the condenser 15 is taken away by the circulating water.

[0049] The turbine cooler is an air / water heat exchanger, and the low-pressure feed water output by the low-pressure economizer flows into the turbine cooler. The modified gas turbine cooling system has a more flexible working mode compared with that before modification.

[0050] After the single gas turbine starts, the steam turbine cylinder is preheated by using the waste heat of the air at the same time. The preheating method is as follows: Open the second electric valve 30, the fifth electric valve 33 and the sixth electric valve 34. The feed water output by the low-pressure economizer absorbs heat in the second turbine cooler 8 and evaporates into superheated steam. The pressure of the steam is about 0.6 MPa. Open the third electric valve 31 and supplement the steam volume through the auxiliary steam header 25 to ensure the demand for cylinder preheating. At the initial stage of the gas turbine startup, the steam temperature is insufficient, and the electric heater 9 is put into use to ensure that the temperature of the steam for cylinder preheating reaches above 300 °C. After the gas turbine starts, open the high-pressure bypass hydraulic valve 28, the intermediate-pressure bypass hydraulic valve 27 and the low-pressure bypass hydraulic valve 24, and send the steam that does not reach the steam turbine rotation starting parameters into the condenser 15. Open the high-pressure cylinder reverse warming valve 35, the intermediate-pressure cylinder preheating valve 23, the high-pressure cylinder drain valve 18, the intermediate-pressure cylinder drain valve 20 and the low-pressure cylinder drain valve 22 in advance. Confirm that the high-pressure main steam valve 17 and the intermediate-pressure main steam valve 19 are closed, and carry out reverse warming of the high-pressure cylinder 12 and the intermediate-pressure cylinder 11, so that the warming steam enters the high-pressure cylinder 12 and the intermediate-pressure cylinder 11. The drain water discharged from the high-pressure cylinder 12, the intermediate-pressure cylinder 11 and the low-pressure cylinder 10 enters the condenser 15. When the cylinder bodies of the high-pressure cylinder 12 and the intermediate-pressure cylinder 11 are preheated to about 240 °C, stop the reverse warming, close the high-pressure cylinder reverse warming valve 35 and the intermediate-pressure cylinder preheating valve 23. Wait until the superheated steam parameters generated by the waste heat boiler 14 meet the steam turbine rotation starting parameters, then open the high-pressure main steam valve 17 and the intermediate-pressure main steam valve 19 to carry out warm startup, so that the steam turbine rotates to 3000 r / min in a shorter time, and then is synchronized to the grid. As the load increases, gradually close the high-pressure bypass hydraulic valve 28, the intermediate-pressure bypass hydraulic valve 27 and the low-pressure bypass hydraulic valve 24.

[0051] After the preheating is completed, the combined cycle unit is synchronized to the grid and enters the load increasing control. The first turbine cooler 7 is also put into use. Open the first electric valve 29 and the fourth electric valve 32, start the small-flow intermediate-pressure feed water pump 6. The intermediate-pressure feed water absorbs heat in the first turbine cooler 7 and then enters the natural gas preheater 3 to heat the natural gas, heating the cold natural gas to the target temperature corresponding to the current load of the unit. The cooled intermediate-pressure feed water converges with the outlet of the intermediate-pressure feed water pump of the waste heat boiler 14. The second turbine cooler 8 continues to be put into use. Close the third electric valve 31 and stop using the electric heater 9. After the gas turbine load increases, open the intermediate-pressure cylinder preheating valve 23 again. At this time, the steam turbine unit has carried the load. The steam generated by the second turbine cooler 8 enters the low-pressure cylinder 10 to do work together with the exhaust steam of the intermediate-pressure cylinder 11 after passing through the intermediate-pressure cylinder preheating valve 23. By adjusting the opening of the sixth electric valve 34, the mixed air reaches the target temperature for cooling the blades in the turbine 4.

[0052] Other embodiments of the present invention will be readily apparent to those skilled in the art in view of the specification and the 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 known common knowledge or conventional technical means in the technical field not disclosed in the present invention. The specification and examples are only illustrative, and the true scope and spirit of the present invention are pointed out 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] The above 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 according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A system for shortening the startup time of a unit by utilizing the waste heat of a gas turbine cooling system, characterized in that, It includes a waste heat boiler (14), a natural gas preheater (3), a second turbine cooler (8), an electric heater (9), an auxiliary steam header (25), an intermediate pressure cylinder (11) and a high pressure cylinder (12); The outlet of the low and medium temperature economizer of the waste heat boiler (14) is divided into two paths. Among them, one path is connected to the heat release side of the natural gas preheater (3) through a first electric valve (29), a small flow intermediate pressure feed water pump (6) and the heat absorption side of the first turbine cooler (7); the other path is connected to the inlet of the heat absorption side of the second turbine cooler (8) through a second electric valve (30). The outlet of the heat absorption side of the second turbine cooler (8) is connected to the inlet of the electric heater (9). The outlet of the auxiliary steam header (25) is connected to the inlet of the electric heater (9) through a third electric valve (31). The outlet of the electric heater (9) is connected to the outlet of the intermediate pressure cylinder (11) through an intermediate pressure cylinder prewarming valve (23). The outlet of the electric heater (9) is connected to the outlet of the high pressure cylinder (12) through a high pressure cylinder reverse warming valve (35).

2. The system for shortening the startup time of the unit by utilizing the waste heat of the gas turbine cooling system according to claim 1, wherein It also includes a natural gas input pipeline, a combustion chamber (2), a turbine (4) and a compressor (1); The natural gas input pipeline is connected to the inlet of the combustion chamber (2) through the heat absorption side of the natural gas preheater (3). The outlet of the combustion chamber (2) is connected to the inlet of the turbine (4). The outlet of the compressor (1) is connected to the inlet of the combustion chamber (2). The extraction port of the compressor (1) is divided into three paths. Among them, the first path is connected to the inlet of the turbine (4) through a fourth electric valve (32) and the heat release side of the first turbine cooler (7). The second path is connected to the inlet of the turbine (4) through a fifth electric valve (33) and the heat release side of the second turbine cooler (8). The third path is connected to the inlet of the turbine (4) through a sixth electric valve (34). The flue gas outlet of the turbine (4) is connected to the flue gas inlet of the waste heat boiler (14).

3. The system for shortening the startup time of the unit by utilizing the waste heat of the gas turbine cooling system according to claim 2, wherein The main steam outlet of the waste heat boiler (14) is connected to the inlet of the high pressure cylinder (12) through a high pressure main steam valve (17). The outlet of the high pressure cylinder (12) is connected to the inlet of the reheating side of the waste heat boiler (14) through a high pressure exhaust non-return valve (26). The outlet of the reheating side of the waste heat boiler (14) is connected to the inlet of the intermediate pressure cylinder (11) through an intermediate pressure main steam valve (19). The outlet of the intermediate pressure cylinder (11) is connected to the inlet of the low pressure cylinder (10) through a low pressure main steam valve (21). The outlet of the low pressure cylinder (10) is connected to the feed water inlet of the waste heat boiler (14) through a condenser (15) and a condensate pump (16).

4. The system for shortening the start-up time of the unit by utilizing the waste heat of the gas turbine cooling system according to claim 3, wherein The main steam outlet and the inlet of the reheating side of the waste heat boiler (14) are connected through a high bypass hydraulic valve (28).

5. The system for shortening the start-up time of a unit by utilizing the waste heat of a gas turbine cooling system according to claim 4, wherein The superheated steam outlet of the waste heat boiler (14) is connected to the inlet of the condenser (15) through an intermediate bypass hydraulic valve (27).

6. The system for shortening the startup time of the unit by utilizing the waste heat of the gas turbine cooling system according to claim 5, wherein The outlet of the intermediate pressure cylinder (11) is connected to the inlet of the condenser (15) through a low bypass hydraulic valve (24).

7. The system for shortening the startup time of the unit by utilizing the waste heat of the gas turbine cooling system according to claim 6, wherein A low pressure cylinder drain valve (22) is provided at the drain outlet of the low pressure cylinder (10), a middle pressure cylinder drain valve (20) is provided at the drain port of the intermediate pressure cylinder (11), and a high pressure cylinder drain valve (18) is provided at the drain port of the high pressure cylinder (12).

8. The system for shortening the startup time of the unit by utilizing the waste heat of the gas turbine cooling system according to claim 4, wherein The compressor (1), the turbine (4) and the first generator (5) are coaxially arranged.

9. The system for shortening the start-up time of a unit by utilizing the waste heat of a gas turbine cooling system according to claim 4, wherein The low-pressure cylinder (10), the intermediate-pressure cylinder (11), the high-pressure cylinder (12) and the second generator (13) are coaxially arranged.

10. A method for shortening the start-up time of a unit by utilizing the waste heat of a gas turbine cooling system, characterized in that, The system for shortening the start-up time of the unit by utilizing the waste heat of the gas turbine cooling system according to claim 7, comprising the following steps: Open the second electric valve (30), the fifth electric valve (33) and the sixth electric valve (34). The feed water output from the low-pressure economizer absorbs heat and evaporates into superheated steam in the second turbine cooler (8). Open the third electric valve (31), and supplement the steam quantity through the auxiliary steam header (25) to ensure the cylinder preheating requirement. When the steam temperature is insufficient at the initial stage of the gas turbine start-up, the electric heater (9) is put into operation. After the gas turbine starts up, open the high bypass hydraulic valve (28), the intermediate bypass hydraulic valve (27) and the low bypass hydraulic valve (24), and send the steam that does not reach the steam turbine rotation-impulse parameter into the condenser (15). Open the high-pressure cylinder reverse warming valve (35), the intermediate-pressure cylinder prewarming valve (23), the high-pressure cylinder drain valve (18), the intermediate-pressure cylinder drain valve (20) and the low-pressure cylinder drain valve (22) in advance. Confirm that the high-pressure main steam valve (17) and the intermediate-pressure main steam valve (19) are closed, and perform reverse warming of the high-pressure cylinder (12) and the intermediate-pressure cylinder (11) so that the warming steam enters the high-pressure cylinder (12) and the intermediate-pressure cylinder (11). The drain water discharged from the high-pressure cylinder (12), the intermediate-pressure cylinder (11) and the low-pressure cylinder (10) enters the condenser (15). When the cylinder bodies of the high-pressure cylinder (12) and the intermediate-pressure cylinder (11) are preheated to the preset temperature, stop the reverse warming and close the high-pressure cylinder reverse warming valve (35) and the intermediate-pressure cylinder prewarming valve (23). Wait until the superheated steam parameters generated by the waste heat boiler (14) meet the steam turbine rotation-impulse parameters, then open the high-pressure main steam valve (17) and the intermediate-pressure main steam valve (19) to perform warm start-up, and then synchronize to the grid. As the load increases, gradually close the high bypass hydraulic valve (28), the intermediate bypass hydraulic valve (27) and the low bypass hydraulic valve (24).

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