A starting system for shortening the time of yellow smoke emission from chimney of combined cycle generator set

Abstract

The present invention discloses a starting system for shortening the time when yellow smoke comes out of the chimney of a combined cycle power generation unit, comprising a steam drum, a preheater, an economizer, a low-pressure evaporator, a medium-pressure evaporator, a high-pressure evaporator and a superheater, etc. The present invention is aimed at the high, medium and low-pressure steam generation system of the waste heat boiler, adopts a method of preheating before the unit is started, in addition to designing auxiliary steam heating under the high, medium and low-pressure evaporators, a preheater with a heating function is also designed, before the unit is started, auxiliary heating steam is introduced into the preheater to preheat the condensed water from the condenser, to ensure that after the gas turbine is ignited and started, the high, medium and low-pressure steam generation system of the waste heat boiler quickly generates high-temperature and high-pressure steam under the heating of the high-temperature flue gas exhaust of the gas turbine, and meets the requirements of the steam parameters for the warm-up of the steam turbine, so as to realize the rapid start-up of the waste heat boiler and the steam turbine at the same time, shorten the start-up time of the generator set, and reduce the generation of pollutants during the start-up process.

Description

Technical Field

[0001] The invention relates to a waste heat boiler system, in particular to a starting system capable of shortening the yellow smoke emission time of a chimney of a combined cycle generator set. Background Art

[0002] The main pollutant generated during the combustion process of heavy-duty gas turbines that use gaseous fuels such as natural gas is NOx. In order to reduce NOx emissions, in-service heavy-duty gas turbines generally use lean premixed combustion technology. However, the stability of lean premixed combustion is poorer than that of diffusion combustion, and it is easy to cause combustion instability problems during variable operating conditions such as startup. Therefore, in order to ensure the smooth start-up of the gas turbine generator set, the gas turbine still uses diffusion combustion or staged combustion technology dominated by diffusion combustion during the startup process. After the gas turbine reaches a certain load, it switches to the lean premixed combustion mode.

[0003] Since the gas turbine uses diffusion combustion during the startup process, and the temperature of the diffusion combustion flame surface is usually as high as 2000-2200℃, a large amount of NO is generated; at the same time, the amount of air in the startup stage is much higher than the amount of air required for theoretical full combustion of the fuel, the residual oxygen content in the flue gas after combustion is high, and there are high levels of CO and unburned hydrocarbons generated by incomplete combustion due to the low average temperature of the flue gas. These factors promote the conversion of NO to NO2, which significantly increases the concentration of NO2 in the flue gas. NO2 is a reddish-brown gas, which becomes yellow-brown after dilution, resulting in the obvious yellow smoke phenomenon in the chimney during the startup of the gas turbine.

[0004] For gas-steam combined cycle power generation units, the startup time of the power generation units is generally longer due to the startup speed of the waste heat boiler and the warm-up time of the steam turbine. The startup of gas-steam combined cycle power generation units is generally divided into cold startup, warm startup and hot startup. The cold startup time is the longest and the hot startup time is the shortest. However, even for hot startup, the startup time takes about 50 minutes. Although the current national thermal power generation emission regulations do not include the pollutant emissions during the startup process of gas turbines as an assessment indicator, the pollutant emissions during the startup process cannot be ignored. Summary of the invention

[0005] In order to reduce the NOx emission during the startup process of the gas-steam combined cycle power generation unit and solve the problem of long startup time of the waste heat boiler, the present invention proposes a startup system that shortens the time for the chimney of the combined cycle power generation unit to emit yellow smoke. The present invention is aimed at the high, medium and low pressure steam generation system of the waste heat boiler, adopts a method of preheating before the unit is started, in addition to designing auxiliary steam heating under the high, medium and low pressure evaporators, a preheater with a heating function is also designed. Before the unit is started, auxiliary heating steam is introduced into the preheater to preheat the condensed water from the condenser, ensuring that after the gas turbine is ignited and started, the high, medium and low pressure steam generation system of the waste heat boiler quickly generates high temperature and high pressure steam under the heating of the high temperature flue gas exhaust of the gas turbine, and meets the requirements of the steam parameters for the warm-up of the steam turbine, so as to achieve the rapid startup of the waste heat boiler and the steam turbine at the same time, shorten the startup time of the generator set, and reduce the generation of pollutants during the startup process.

[0006] The present invention is achieved by adopting the following technical solutions:

[0007] A starting system for shortening the time of yellow smoke emission from the chimney of a combined cycle power generation unit comprises a low-pressure drum, a medium-pressure drum, a high-pressure drum, a preheater, a low-pressure economizer, a medium-pressure economizer, a high-pressure economizer, a low-pressure evaporator, a medium-pressure evaporator, a high-pressure evaporator, a low-pressure superheater, a medium-pressure superheater and a high-pressure superheater; wherein,

[0008] The preheater is arranged at the front end of the waste heat boiler startup system, and a return water main pipe, a preheater steam recovery pipe and a preheater condensate supply pipe are arranged at the top of the preheater, a low-pressure water supply pipe is arranged at the middle and upper part of the preheater, and a preheater bubble disperser is arranged at the bottom of the preheater; after the auxiliary steam enters the preheater from the bottom, it forms uniformly rising high-temperature bubbles through the preheater bubble disperser to heat the condensate in the preheater;

[0009] A low-pressure water outlet pipe is provided at the bottom of the low-pressure drum, which is connected to the medium-pressure water supply pipe and the high-pressure water supply pipe respectively, and is used to transport the water heated in the low-pressure drum to the medium-pressure drum and the high-pressure drum;

[0010] A medium-pressure drum return pipe is provided at the bottom of the medium-pressure drum, which is used to return water from the medium-pressure drum when the waste heat boiler is preheated in advance. When the water level of the medium-pressure drum reaches a preset value, it flows back to the preheater through the medium-pressure drum return pipe to prevent the medium-pressure drum from being filled with water and causing danger;

[0011] A high-pressure drum return pipe is provided at the bottom of the high-pressure drum for returning water to the high-pressure drum when the waste heat boiler is preheated in advance. When the water level of the high-pressure drum reaches a preset value, it flows back to the preheater through the high-pressure drum return pipe to prevent the high-pressure drum from being filled with water and causing danger;

[0012] The low-pressure economizer is connected to the low-pressure drum and arranged at the most downstream of the flue gas flow direction of the waste heat boiler, and uses the flue gas heat to heat the condensed water preheated by the preheater;

[0013] The low-pressure evaporator is connected to the low-pressure drum and arranged upstream of the low-pressure economizer. A low-pressure evaporator preheating steam pipe is provided at the bottom of the low-pressure evaporator. When the waste heat boiler is preheated in advance, the auxiliary steam heats the condensed water in the low-pressure evaporator through the low-pressure evaporator preheating steam pipe;

[0014] The low-pressure superheater is connected to the low-pressure drum and arranged upstream of the low-pressure evaporator. When the waste heat boiler wastes heat in advance, the preheated auxiliary steam in the low-pressure drum can be recovered from the low-pressure steam bypass through the low-pressure superheater;

[0015] The medium-pressure economizer is connected to the medium-pressure drum and arranged upstream of the low-pressure superheater of the waste heat boiler to heat the low-pressure drum water diverted from the low-pressure outlet main pipe by the medium-pressure feed water pipe;

[0016] The medium-pressure evaporator is connected to the medium-pressure drum and arranged upstream of the medium-pressure economizer. A medium-pressure evaporator preheating steam pipe is provided at the bottom of the medium-pressure evaporator. When the waste heat boiler is preheated in advance, the auxiliary steam heats the condensed water in the medium-pressure evaporator through the medium-pressure evaporator preheating steam pipe;

[0017] The medium-pressure superheater is connected to the medium-pressure drum and arranged upstream of the medium-pressure evaporator. When the waste heat boiler wastes heat in advance, the preheated auxiliary steam in the medium-pressure drum can be recovered from the medium-pressure steam bypass through the medium-pressure superheater;

[0018] The high-pressure economizer is connected to the high-pressure drum and arranged upstream of the medium-pressure superheater of the waste heat boiler to heat the low-pressure drum water diverted from the low-pressure water outlet main pipe by the high-pressure feed water pipe;

[0019] The high-pressure evaporator is connected to the high-pressure steam drum and arranged upstream of the high-pressure economizer. A high-pressure evaporator preheating steam pipe is provided at the bottom of the high-pressure evaporator. When the waste heat boiler is preheated in advance, the auxiliary steam heats the condensed water in the high-pressure evaporator through the high-pressure evaporator preheating steam pipe;

[0020] The high-pressure superheater is connected to the high-pressure steam drum and arranged upstream of the high-pressure evaporator. When the waste heat boiler wastes heat in advance, the preheated auxiliary steam in the high-pressure steam drum can be recovered from the high-pressure steam bypass through the high-pressure superheater.

[0021] A further improvement of the present invention is that the preheater is in the shape of an upright cylindrical tank structure.

[0022] A further improvement of the present invention is that the preheater bubble disperser is a hollow circular sandwich structure.

[0023] A further improvement of the present invention is that a plurality of steam injection holes are evenly arranged on the upper circular plate.

[0024] A further improvement of the present invention is that a preheater sewage pipe and a preheater auxiliary steam pipe are also provided at the bottom of the preheater.

[0025] A further improvement of the present invention is that a preheater auxiliary steam regulating valve is provided on the preheater auxiliary steam pipe.

[0026] A further improvement of the present invention is that a low-pressure evaporator preheating steam regulating valve is provided on the low-pressure evaporator preheating steam pipe.

[0027] A further improvement of the present invention is that a medium-pressure evaporator preheating steam regulating valve is provided on the medium-pressure evaporator preheating steam pipe.

[0028] A further improvement of the present invention is that a high-pressure evaporator preheating steam regulating valve is provided on the high-pressure evaporator preheating steam pipe.

[0029] A further improvement of the present invention is that a preheater steam recovery control valve is provided on the preheater steam recovery pipe.

[0030] The present invention has at least the following beneficial technical effects:

[0031] The present invention provides a starting system for shortening the time when yellow smoke comes out of the chimney of a combined cycle power generation unit. The system adopts a method of preheating condensed water of the waste heat boiler before starting the power generation unit, and an auxiliary steam heating device is designed below the high, medium and low pressure evaporators of the waste heat boiler. The auxiliary steam is used to heat the condensed water in the high, medium and low pressure evaporators of the waste heat boiler in advance, thereby shortening the evaporation time of the condensed water after the high-temperature flue gas of the gas turbine is discharged into the waste heat boiler. At the same time, because a preheater with a heating function is designed outside the furnace, the auxiliary steam can be used to heat the condensed water in the high, medium and low pressure economizers and the steam drum of the waste heat boiler in the preheater, so that the waste heat boiler can be started quickly, thereby shortening the starting time of the gas-steam combined cycle power generation unit, and having the advantage of reducing the pollutant emissions during the starting process. At the same time, because the starting time is shortened, the steam turbine can be warmed up and connected to the grid for power generation earlier, thereby improving the economic benefit of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a schematic diagram of a starting system for shortening the time for yellow smoke to come out of a chimney of a combined cycle power generation unit.

[0033] Figure 2 It is a schematic diagram of the preheater in the present invention.

[0034] Description of reference numerals:

[0035] 1. Low-pressure drum; 2. Medium-pressure drum; 3. High-pressure drum; 4. Low-pressure feedwater pump; 5. Low-pressure economizer; 6. Low-pressure evaporator; 7. Low-pressure superheater; 8. Medium-pressure feedwater pump; 9. Medium-pressure economizer; 10. Medium-pressure evaporator; 11. Medium-pressure superheater; 12. High-pressure feedwater pump; 13. High-pressure economizer; 14. High-pressure evaporator; 15. High-pressure superheater; 16. Preheater; 17. Low-pressure drum pressure relief valve; 18. Low-pressure drum pressure relief pipe; 19. Low-pressure water outlet pipe; 20. Low-pressure feedwater pipe; 21. Preheater auxiliary steam pipe; 22. Preheater auxiliary steam regulation valve; 23, preheater blowdown pipe; 24, preheater blowdown control valve; 25, low-pressure evaporator preheating steam pipe; 26, low-pressure evaporator preheating steam regulating valve; 27, low-pressure evaporator blowdown control valve; 28, low-pressure evaporator blowdown pipe; 29, low-pressure steam main pipe; 30, low-pressure drum downcomer; 31, low-pressure drum downwater control valve; 32, medium-pressure drum pressure relief valve; 33, medium-pressure drum pressure relief pipe; 34, return water main pipe; 35, medium-pressure drum return water regulating valve; 36, medium-pressure drum return water pipe; 37, medium-pressure feed water pipe; 38, medium-pressure evaporator preheating steam pipe; 39, Preheating steam regulating valve for medium-pressure evaporator; 40. Blowdown control valve for medium-pressure evaporator; 41. Blowdown pipe for medium-pressure evaporator; 42. Main pipe for medium-pressure steam; 43. Downcomer for medium-pressure drum; 44. Downcomer control valve for medium-pressure drum; 45. Pressure relief valve for high-pressure drum; 46. Pressure relief pipe for high-pressure drum; 47. Return water regulating valve for high-pressure drum; 48. Return water pipe for high-pressure drum; 49. High-pressure feed water pipe; 50. Preheating steam pipe for high-pressure evaporator; 51. Preheating steam regulating valve for high-pressure evaporator; 52. Blowdown control valve for high-pressure evaporator; 53. Blowdown pipe for high-pressure evaporator; 54. Main pipe for high-pressure steam; 55. High-pressure steam drum downcomer; 56. High-pressure steam drum downcomer control valve; 57. Preheater steam recovery control valve; 58. Preheater steam recovery pipe; 59. Low-pressure steam bypass regulating valve; 60. Low-pressure steam bypass; 61. Low-pressure steam main line regulating valve; 62. Medium-pressure steam bypass regulating valve; 63. Medium-pressure steam bypass; 64. Medium-pressure steam main line regulating valve; 65. High-pressure steam bypass regulating valve; 66. High-pressure steam bypass; 67. High-pressure steam main line regulating valve; 68. Preheater condensate supply pipe; 69. Preheater condensate pump; 70. Preheater bubble disperser. DETAILED DESCRIPTION

[0036] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0037] See also Figure 1 and Figure 2The present invention provides a startup system for shortening the yellow smoke emission time of a combined cycle power generation unit chimney, which mainly includes a low-pressure drum 1, a medium-pressure drum 2, a high-pressure drum 3, a preheater 16, a low-pressure economizer 5, a medium-pressure economizer 9, a high-pressure economizer 13, a low-pressure evaporator 6, a medium-pressure evaporator 10, a high-pressure evaporator 14, a low-pressure superheater 7, a medium-pressure superheater 11, a high-pressure superheater 15, etc. The low-pressure drum 1, the low-pressure economizer 5, the medium-pressure economizer 9, the high-pressure economizer 13, the low-pressure superheater 7, the medium-pressure superheater 11 and the high-pressure superheater 15 are the same as those of a traditional preheating boiler.

[0038] See also Figure 1 In this embodiment, the preheating system is mainly composed of a preheater 16, a preheater auxiliary steam pipe 21, a preheater auxiliary steam regulating valve 22, a preheater blowdown pipe 23, a preheater blowdown control valve 24, a low-pressure evaporator preheating steam pipe 25, a low-pressure evaporator preheating steam regulating valve 26, a return water main pipe 34, a medium-pressure drum return water regulating valve 35, a medium-pressure drum return water pipe 36, a medium-pressure evaporator preheating steam pipe 38, a medium-pressure evaporator preheating steam regulating valve 39, a high-pressure drum return water regulating valve 47, a high-pressure drum return water pipe 48, a high-pressure evaporator preheating steam pipe 50, a high-pressure evaporator preheating steam regulating valve 51, a preheater steam recovery control valve 57, a preheater steam recovery pipe 58, a preheater condensate supply pipe 68 and a preheater condensate pump 69. The preheater 16 is arranged at the front end of the waste heat boiler startup system. A return water main pipe 34, a preheater steam recovery pipe 58 and a preheater condensate supply pipe 68 are arranged at the top of the preheater 16. A low-pressure water supply pipe 20 is arranged in the upper and middle part of the preheater 16. A preheater drain pipe 23, a preheater auxiliary steam pipe 21 and a preheater bubble disperser 70 are arranged at the bottom of the preheater 16. After the auxiliary steam enters the preheater 16 from the bottom, it forms uniformly rising high-temperature bubbles through the preheater bubble disperser 70 to heat the condensate in the preheater 16.

[0039] In this embodiment, the low-pressure steam system is mainly composed of a low-pressure steam drum 1, a low-pressure feed water pump 4, a low-pressure economizer 5, a low-pressure evaporator 6, a low-pressure superheater 7, a low-pressure steam drum pressure relief valve 17, a low-pressure steam drum pressure relief pipe 18, a low-pressure water outlet main pipe 19, a low-pressure feed water pipe 20, a low-pressure evaporator sewage control valve 27, a low-pressure evaporator sewage pipe 28, a low-pressure steam main pipe 29, a low-pressure steam drum downcomer 30, a low-pressure steam drum downcomer control valve 31, a low-pressure steam bypass regulating valve 59, a low-pressure steam bypass 60 and a low-pressure steam main regulating valve 61. The low-pressure economizer 5 is connected to the low-pressure steam drum 1 and arranged at the most downstream of the flue gas flow direction of the waste heat boiler, and uses the heat of the flue gas to heat the condensed water preheated by the preheater 16; the low-pressure evaporator 6 is connected to the low-pressure steam drum 1, and the low-pressure evaporator 6 is arranged upstream of the low-pressure economizer 5. A low-pressure evaporator preheating steam pipe 25 is provided at the bottom of the low-pressure evaporator 6. When the waste heat boiler is preheated in advance, auxiliary steam heats the condensed water in the low-pressure evaporator 6 through the low-pressure evaporator preheating steam pipe 25; the low-pressure superheater 7 is connected to the low-pressure steam drum 1 and arranged upstream of the low-pressure evaporator 6. When the waste heat boiler is preheated in advance, the preheated auxiliary steam in the low-pressure steam drum 1 can be recovered from the low-pressure steam bypass 60 through the low-pressure superheater 7.

[0040] In this embodiment, the medium-pressure steam system is mainly composed of a medium-pressure steam drum 2, a medium-pressure feed water pump 8, a medium-pressure economizer 9, a medium-pressure evaporator 10, a medium-pressure superheater 11, a medium-pressure steam drum pressure relief valve 32, a medium-pressure steam drum pressure relief pipe 33, a medium-pressure feed water pipe 37, a medium-pressure evaporator sewage control valve 40, a medium-pressure evaporator sewage pipe 41, a medium-pressure steam main pipe 42, a medium-pressure steam drum downcomer 43, a medium-pressure steam drum downcomer control valve 44, a medium-pressure steam bypass regulating valve 62, a medium-pressure steam bypass 63 and a medium-pressure steam main regulating valve 64. Among them, the medium-pressure economizer 9 is connected to the medium-pressure steam drum 2, and is arranged upstream of the low-pressure superheater 7 of the waste heat boiler, and is used to heat the low-pressure steam drum water diverted from the low-pressure water outlet mother pipe 19 by the medium-pressure feed water pipe 37; the medium-pressure evaporator 10 is connected to the medium-pressure steam drum 2, and the medium-pressure evaporator 10 is arranged upstream of the medium-pressure economizer 9. A medium-pressure evaporator preheating steam pipe 38 is provided at the bottom of the medium-pressure evaporator 10. When the waste heat boiler is preheated in advance, auxiliary steam heats the condensed water in the medium-pressure evaporator 10 through the medium-pressure evaporator preheating steam pipe 38; the medium-pressure superheater 11 is connected to the medium-pressure steam drum 2, and the medium-pressure superheater 11 is arranged upstream of the medium-pressure evaporator 10. When the waste heat boiler is preheated in advance, the preheated auxiliary steam in the medium-pressure steam drum 2 can be recovered from the medium-pressure steam bypass 63 through the medium-pressure superheater 11.

[0041] In this embodiment, the high-pressure steam system is mainly composed of a high-pressure steam drum 3, a high-pressure feed water pump 12, a high-pressure economizer 13, a high-pressure evaporator 14, a high-pressure superheater 15, a high-pressure steam drum pressure relief valve 45, a high-pressure steam drum pressure relief pipe 46, a high-pressure feed water pipe 49, a high-pressure evaporator sewage control valve 52, a high-pressure evaporator sewage pipe 53, a high-pressure steam main pipe 54, a high-pressure steam drum downcomer 55, a high-pressure steam drum downcomer control valve 56, a high-pressure steam bypass regulating valve 65, a high-pressure steam bypass 66 and a high-pressure steam main regulating valve 67. Among them, the high-pressure economizer 13 is connected to the high-pressure steam drum 3, and is arranged upstream of the medium-pressure superheater 11 of the waste heat boiler, and is used to heat the low-pressure steam drum water diverted from the low-pressure water outlet mother pipe 19 by the high-pressure feed water pipe 49; the high-pressure evaporator 14 is connected to the high-pressure steam drum 3, and the high-pressure evaporator 14 is arranged upstream of the high-pressure economizer 13. A high-pressure evaporator preheating steam pipe 50 is provided at the bottom of the high-pressure evaporator 14. When the waste heat boiler is preheated in advance, auxiliary steam heats the condensed water in the high-pressure evaporator 14 through the high-pressure evaporator preheating steam pipe 50; the high-pressure superheater 15 is connected to the high-pressure steam drum 3, and is arranged upstream of the high-pressure evaporator 14. When the waste heat boiler is preheated in advance, the preheated auxiliary steam in the high-pressure steam drum 3 can be recovered from the high-pressure steam bypass 66 through the high-pressure superheater 15.

[0042] See also Figure 2 A preheater bubble disperser 70 is designed at the bottom of the preheater 16 .

[0043] The specific working method of the starting system for shortening the yellow smoke emission time of the chimney of the combined cycle power generation unit in this embodiment is as follows:

[0044] When the waste heat boiler startup system is working, the preheater blowdown control valve 24, the low-pressure evaporator blowdown control valve 27, the low-pressure drum down-water control valve 31, the medium-pressure evaporator blowdown control valve 40, the medium-pressure drum down-water control valve 44, the high-pressure evaporator blowdown control valve 52, the high-pressure drum down-water control valve 56, the low-pressure steam main line regulating valve 61, the medium-pressure steam main line regulating valve 64, and the high-pressure steam main line regulating valve 67 are closed, and the preheater auxiliary steam regulating valve 22, the low-pressure evaporator preheating steam regulating valve 26, the medium-pressure drum return water regulating valve 35, the medium-pressure evaporator preheating steam regulating valve 39, the high-pressure drum return water regulating valve 47, the high-pressure evaporator preheating steam regulating valve 51, the preheater steam recovery control valve 57, the low-pressure steam bypass regulating valve 59, the medium-pressure steam bypass regulating valve 62, and the high-pressure steam bypass regulating valve 65 are opened. The preheater condensate pump 69 is turned on and the condensate enters the preheater 16 from the top of the preheater 16 through the preheater condensate supply pipe 68. At the same time, the auxiliary steam passes through the preheater auxiliary steam pipe 21 from the bottom of the preheater 16 and then passes through the preheater bubble disperser 70 to form uniform high-temperature bubbles, which directly contact the condensate in the preheater 16 to exchange heat. The exhaust steam after the heat exchange returns to the auxiliary steam generation system from the preheater steam recovery pipe 58 at the head of the preheater 16. The water at the bottom of the preheater 16 is the first to contact with the auxiliary steam bubbles, and the water temperature is higher and the density is lower, so a natural upward lift is formed. The condensate entering the preheater 16 from the return water main pipe 34 and the preheater condensate supply pipe 68 has a lower water temperature and a higher density, so it naturally drops to the bottom of the preheater 16, so that the water circulation in the preheater 16 is heated by the auxiliary steam.

[0045] The condensed water heated in the preheater 16 enters the low-pressure economizer 5 through the low-pressure water supply pipe 20 under the suction action of the low-pressure water supply pump 4, and exchanges heat with the condensed water originally existing in the low-pressure water supply pump 5, and then enters the low-pressure steam drum 1 to heat the condensed water originally existing in the low-pressure steam drum 1; the condensed water in the low-pressure steam drum simultaneously flows into the low-pressure water outlet pipe 19 during the heating process, and enters the medium-pressure economizer 9 through the medium-pressure water supply pipe 37 under the suction action of the medium-pressure water supply pump 8, and exchanges heat with the condensed water originally existing in the medium-pressure water supply pump 9, and then enters the medium-pressure water supply pump 8. Drum 2, heating the condensed water originally existing in the medium-pressure drum 2; under the suction action of the high-pressure feed water pump 12, it enters the high-pressure economizer 13 through the high-pressure feed water pipe 49, and exchanges heat with the condensed water originally existing in the high-pressure economizer 13, and then enters the high-pressure drum 3, heating the condensed water originally existing in the high-pressure drum 3; at the same time, the condensed water in the medium-pressure drum 2 and the high-pressure drum 3 respectively flows into the return water mother pipe 34 through the medium-pressure drum return water pipe 36 and the high-pressure drum return water pipe 48 during the heating process, and finally enters the preheater 16 from the top of the preheater 16 to be heated again.

[0046] While the condensed water in the preheater 16, the low-pressure economizer 5, the medium-pressure economizer 9, the high-pressure economizer 13, the low-pressure drum 1, the medium-pressure drum 2 and the high-pressure drum 3 is heated by the auxiliary steam, the auxiliary steam enters the low-pressure evaporator 6, the medium-pressure evaporator 10 and the high-pressure evaporator 14 through the low-pressure evaporator preheating steam pipe 25, the medium-pressure evaporator preheating steam pipe 38 and the high-pressure evaporator preheating steam pipe 50 respectively to heat the condensed water originally existing in the evaporator. The exhausted steam after the heat exchange then enters the low-pressure drum 1, the medium-pressure drum 2 and the high-pressure drum 3 respectively to further heat the condensed water in the drum, and finally returns to the auxiliary steam generation system through the low-pressure steam bypass 60, the medium-pressure steam bypass 63 and the high-pressure steam bypass 66 respectively to be heated, so as to form new high-temperature auxiliary steam for the waste heat boiler startup system.

[0047] When the condensed water in the waste heat boiler is heated to the required temperature, start the gas turbine, close the preheater auxiliary steam regulating valve 22, the low-pressure evaporator preheating steam regulating valve 26, the medium-pressure drum return water regulating valve 35, the medium-pressure evaporator preheating steam regulating valve 39, the high-pressure drum return water regulating valve 47, the high-pressure evaporator preheating steam regulating valve 51, and the preheater steam recovery control valve 57, open the low-pressure drum down-water control valve 31, the medium-pressure drum down-water control valve 44, and the high-pressure drum down-water control valve 56, and the high-temperature flue gas after combustion and expansion of the gas turbine is discharged into the waste heat boiler to heat the high-pressure superheater 15, the medium-pressure superheater 11, and the low-pressure superheater 13. The condensed water in the waste heat boiler 7, the high-pressure evaporator 14, the medium-pressure evaporator 10, the low-pressure evaporator 6, the high-pressure economizer 13, the medium-pressure economizer 9 and the low-pressure economizer 5 quickly generates high-temperature and high-pressure steam. After the steam index meets the requirements, the low-pressure steam main regulating valve 61, the medium-pressure steam main regulating valve 64 and the high-pressure steam main regulating valve 67 are opened, and the low-pressure steam bypass regulating valve 59, the medium-pressure steam bypass regulating valve 62 and the high-pressure steam bypass regulating valve 65 are closed at the same time. The steam generated by the waste heat boiler quickly enters the steam turbine for warming up, thereby shortening the start-up time of the gas-steam combined cycle generator set and reducing the emission of pollutants such as NOx during the start-up process.

[0048] The above shows and describes the basic principle, main features and advantages of the present invention. The present invention is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention claimed for protection.

Claims

1. A starting system for shortening the time of yellow smoke emission from the chimney of a combined cycle power generation unit, characterized in that: Including low-pressure drum, medium-pressure drum, high-pressure drum, preheater, low-pressure economizer, medium-pressure economizer, high-pressure economizer, low-pressure evaporator, medium-pressure evaporator, high-pressure evaporator, low-pressure superheater, medium-pressure superheater and high-pressure superheater; among them, The preheater is arranged at the front end of the waste heat boiler startup system, and a return water main pipe, a preheater steam recovery pipe and a preheater condensate supply pipe are arranged at the top of the preheater, a low-pressure water supply pipe is arranged at the middle and upper part of the preheater, and a preheater bubble disperser is arranged at the bottom of the preheater; after the auxiliary steam enters the preheater from the bottom, it forms uniformly rising high-temperature bubbles through the preheater bubble disperser to heat the condensate in the preheater; A low-pressure water outlet main pipe is provided at the bottom of the low-pressure drum, which is connected to the medium-pressure water supply pipe and the high-pressure water supply pipe respectively, and is used to transport the water heated in the low-pressure drum to the medium-pressure drum and the high-pressure drum; A medium-pressure drum return pipe is provided at the bottom of the medium-pressure drum, which is used to return water from the medium-pressure drum when the waste heat boiler is preheated in advance. When the water level of the medium-pressure drum reaches a preset value, it flows back to the preheater through the medium-pressure drum return pipe to prevent the medium-pressure drum from being filled with water and causing danger; A high-pressure drum return pipe is provided at the bottom of the high-pressure drum for returning water to the high-pressure drum when the waste heat boiler is preheated in advance. When the water level of the high-pressure drum reaches a preset value, it flows back to the preheater through the high-pressure drum return pipe to prevent the high-pressure drum from being filled with water and causing danger; The low-pressure economizer is connected to the low-pressure drum and arranged at the most downstream of the flue gas flow direction of the waste heat boiler, and uses the flue gas heat to heat the condensed water preheated by the preheater; The low-pressure evaporator is connected to the low-pressure drum and arranged upstream of the low-pressure economizer. A low-pressure evaporator preheating steam pipe is provided at the bottom of the low-pressure evaporator. When the waste heat boiler is preheated in advance, the auxiliary steam heats the condensed water in the low-pressure evaporator through the low-pressure evaporator preheating steam pipe; The low-pressure superheater is connected to the low-pressure drum and arranged upstream of the low-pressure evaporator. When the waste heat boiler wastes heat in advance, the preheated auxiliary steam in the low-pressure drum can be recovered from the low-pressure steam bypass through the low-pressure superheater; The medium-pressure economizer is connected to the medium-pressure drum and arranged upstream of the low-pressure superheater of the waste heat boiler to heat the low-pressure drum water diverted from the low-pressure outlet main pipe by the medium-pressure feed water pipe; The medium-pressure evaporator is connected to the medium-pressure drum and arranged upstream of the medium-pressure economizer. A medium-pressure evaporator preheating steam pipe is provided at the bottom of the medium-pressure evaporator. When the waste heat boiler is preheated in advance, the auxiliary steam heats the condensed water in the medium-pressure evaporator through the medium-pressure evaporator preheating steam pipe; The medium-pressure superheater is connected to the medium-pressure drum and arranged upstream of the medium-pressure evaporator. When the waste heat boiler wastes heat in advance, the preheated auxiliary steam in the medium-pressure drum can be recovered from the medium-pressure steam bypass through the medium-pressure superheater; The high-pressure economizer is connected to the high-pressure drum and arranged upstream of the medium-pressure superheater of the waste heat boiler to heat the low-pressure drum water diverted from the low-pressure water outlet main pipe by the high-pressure feed water pipe; The high-pressure evaporator is connected to the high-pressure steam drum and arranged upstream of the high-pressure economizer. A high-pressure evaporator preheating steam pipe is provided at the bottom of the high-pressure evaporator. When the waste heat boiler is preheated in advance, the auxiliary steam heats the condensed water in the high-pressure evaporator through the high-pressure evaporator preheating steam pipe; The high-pressure superheater is connected to the high-pressure steam drum and arranged upstream of the high-pressure evaporator. When the waste heat boiler wastes heat in advance, the preheated auxiliary steam in the high-pressure steam drum can be recovered from the high-pressure steam bypass through the high-pressure superheater; The shape of the preheater is a vertical cylindrical tank structure; The preheater bubble disperser is a hollow circular sandwich structure.

2. A starting system for shortening the yellow smoke emission time of a combined cycle power generation unit chimney according to claim 1, characterized in that: A preheater drain pipe and a preheater auxiliary steam pipe are also provided at the bottom of the preheater.

3. A starting system for shortening the yellow smoke emission time of a combined cycle power generation unit chimney according to claim 2, characterized in that: A preheater auxiliary steam regulating valve is provided on the preheater auxiliary steam pipe.

4. A starting system for shortening the yellow smoke emission time of a combined cycle power generation unit chimney according to claim 1, characterized in that: A low-pressure evaporator preheating steam regulating valve is provided on the low-pressure evaporator preheating steam pipe.

5. A starting system for shortening the yellow smoke emission time of a combined cycle power generation unit chimney according to claim 1, characterized in that: A medium-pressure evaporator preheating steam regulating valve is arranged on the medium-pressure evaporator preheating steam pipe.

6. A starting system for shortening the yellow smoke emission time of a combined cycle power generation unit chimney according to claim 1, characterized in that: A high-pressure evaporator preheating steam regulating valve is provided on the high-pressure evaporator preheating steam pipe.

7. A starting system for shortening the yellow smoke emission time of a combined cycle power generation unit chimney according to claim 1, characterized in that: A preheater steam recovery control valve is provided on the preheater steam recovery pipe.

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