Power station deep peak regulation stable combustion operation system

Abstract

The utility model relates to a power station deep peak regulation stable combustion operation system which comprises a power station boiler, a steam turbine high-pressure cylinder, a steam turbine first high-pressure heater, a steam-flue gas heat exchanger, a steam turbine main steam bypass pipeline, a steam turbine first-section steam extraction pipeline and a main steam regulating valve. A power station boiler is divided into two paths through a main steam adjusting valve, one path is connected with a steam turbine high-pressure cylinder, and the other path is connected with a steam-flue gas heat exchanger through a steam turbine main steam bypass pipeline. The steam-flue gas heat exchanger is connected with a first high-pressure heater of the steam turbine; a steam turbine high-pressure cylinder is connected with the steam turbine first high-pressure heater through the steam turbine first-section steam extraction pipeline. And the first high-pressure heater of the steam turbine is connected with the power station boiler. According to the utility model, secondary air and boiler feed water are heated by bypass main steam, so that stable combustion of the boiler under the deep peak regulation operation condition can be ensured, and the working range of the SCR reactor in a denitration system under the deep peak regulation operation condition of the boiler is widened.

Description

Technical Field

[0001] The utility model belongs to the technical field of thermal power generation, and in particular relates to a deep peak regulation and stable combustion operation system of a power station. Background Art

[0002] With the continuous increase in the total installed capacity of new energy, the peak-shaving time of thermal power generating units is getting longer and longer, and the peak-shaving depth is getting deeper. Under such an operating environment, the stable combustion of the boiler and the stable operation of the SCR denitrification system have become major factors affecting the deep peak-shaving of the unit.

[0003] The problem of low SCR inlet flue gas temperature under deep regulation can be solved by adopting the method of economizer staged transformation and economizer hot water side recirculation. However, the transformation cycle is long, the transformation investment is large, and the energy waste is serious after some transformations, which is not conducive to the transformation operation under the background of deep regulation of power plants.

[0004] The existing partial transformation cannot simultaneously guarantee the stable combustion of the boiler under deep peak-shaving operation conditions and the working range of the SCR reactor in the denitrification system under deep peak-shaving operation conditions of the boiler. It is also impossible to utilize the heat of the bypass main steam in a cascade manner to achieve the goal of energy saving and consumption reduction as much as possible during the deep regulation process. Utility Model Content

[0005] The utility model aims to provide a deep peak-shaving stable combustion operation system for a power station, which ensures the stable combustion of the boiler under deep peak-shaving operation conditions by bypassing the main steam to heat the secondary air and boiler feed water, and broadens the working range of the SCR reactor in the denitrification system under the deep peak-shaving operation conditions of the boiler.

[0006] The utility model provides a power station deep peak-shaving and stable combustion operation system, including a power station boiler, a steam turbine high-pressure cylinder, a steam turbine No. 1 high-pressure heater, a steam-flue gas heat exchanger, a steam turbine main steam bypass pipeline, a steam turbine first stage steam extraction pipeline, and a main steam regulating valve;

[0007] The power station boiler is divided into two paths through the main steam regulating valve, one of which is connected to the high-pressure cylinder of the steam turbine, and the other is connected to the steam-flue gas heat exchanger through the main steam bypass pipeline of the steam turbine;

[0008] The steam-flue gas heat exchanger is connected to the No. 1 high-pressure heater of the steam turbine; the high-pressure cylinder of the steam turbine is connected to the No. 1 high-pressure heater of the steam turbine through a section of the steam extraction pipeline of the steam turbine; the No. 1 high-pressure heater of the steam turbine is connected to the power station boiler;

[0009] The power station boiler is used to send out main steam through the main steam regulating valve type main steam into the main steam bypass pipe of the turbine, and enter the steam-flue gas heat exchanger through the main steam bypass pipe of the turbine to exchange heat with the boiler secondary air. The cooled steam enters the turbine No. 1 high-pressure heater through the first section of the turbine extraction pipe to heat the boiler feed water. The boiler feed water enters the power station boiler to absorb heat and then enters the turbine high-pressure cylinder through the main steam pipe.

[0010] Furthermore, the system also includes a boiler secondary air system, and the power station boiler is connected to the steam-flue gas heat exchanger through the boiler secondary air system, which is used to allow the boiler secondary air to be heated by part of the main steam in the steam-flue gas heat exchanger and then re-enter the boiler secondary air system to promote boiler combustion.

[0011] Furthermore, the system also includes an SCR reactor, which is connected to the power station boiler and is used to allow the flue gas to pass through the outlet of the power station boiler economizer and then enter the SCR reactor for flue gas denitrification.

[0012] Through the above scheme, through the deep peak-shaving and stable combustion operation system of the power station, under the deep peak-shaving operation conditions, part of the main steam heat is used to heat the boiler secondary air, increase the temperature of the boiler hot secondary air, and ensure the stable combustion of the boiler under the deep peak-shaving operation conditions; at the same time, the steam after heating the boiler secondary air enters the No. 1 high-pressure heater of the steam turbine, which can increase the temperature of the feed water entering the boiler, thereby increasing the inlet flue gas temperature of the SCR reactor under the deep peak-shaving operation conditions of the boiler, ensuring the activity of the SCR catalyst under the deep peak-shaving operation conditions, and broadening the working range of the denitrification system under the deep peak-shaving operation conditions of the boiler; in addition, bypassing part of the main steam is also conducive to reducing the power generation load of the steam turbine, further realizing the deep peak-shaving of the steam turbine.

[0013] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the utility model in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a deep peak-shaving and stable combustion operation system for a power station of the utility model.

[0015] Markings in the figure:

[0016] 1-power station boiler; 2-steam turbine high-pressure cylinder; 3-steam turbine No. 1 high-pressure heater; 4-SCR reactor; 5-steam-flue gas heat exchanger; 6-boiler secondary air system; 7-steam turbine main steam bypass pipeline; 8-steam turbine first stage steam extraction pipeline; 9-main steam regulating valve. DETAILED DESCRIPTION

[0017] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0018] Ginseng Figure 1 As shown, this embodiment provides a deep peak-shaving and stable combustion operation system for a power plant, including a power plant boiler 1, a turbine high-pressure cylinder 2, a turbine No. 1 high-pressure heater 3, an SCR reactor 4, a steam-flue gas heat exchanger 5, a boiler secondary air system 6, a turbine main steam bypass pipe 7, a turbine first stage extraction pipe 8, and a main steam regulating valve 9; the power plant boiler 1 is divided into two paths through the main steam regulating valve 9, one of which is connected to the turbine high-pressure cylinder 2), and the other is connected to the steam-flue gas heat exchanger 5 through the turbine main steam bypass pipe 7; the steam-flue gas heat exchanger 5 is connected to the turbine No. 1 high-pressure heater 3; the turbine high-pressure cylinder 2 is connected to the turbine No. 1 high-pressure heater 3 through the turbine first stage extraction pipe 8; the turbine No. 1 high-pressure heater 3 is connected to the power plant boiler 1; the power plant boiler 1 is connected to the steam-flue gas heat exchanger 5 through the boiler secondary air system 6; the SCR reactor 4 is connected to the power plant boiler 1.

[0019] When the power generation load drops below 35% under the pure condensing operation state of the steam turbine, the power station boiler 1 sends out the main steam, bypasses part of the main steam through the main steam regulating valve 9 and enters the main steam bypass pipe 7 of the steam turbine, and enters the steam-flue gas heat exchanger 5 through the pipeline connection to exchange heat with the boiler secondary air. After cooling, the steam enters the turbine first-stage extraction pipe 8 to replace the original first-stage extraction steam and enters the turbine No. 1 high-pressure heater 3 to heat the boiler feed water; the boiler feed water enters the power station boiler 1 and absorbs heat and then continues to enter the main steam pipe; the boiler secondary air is heated by part of the main steam in the steam-flue gas heat exchanger 5 and then re-enters the boiler secondary air system 6 to promote boiler combustion; the flue gas passes through the outlet of the economizer of the power station boiler 1 and enters the SCR reactor 4 for flue gas denitrification.

[0020] Taking a 350MW supercritical generating unit as an example, under the original 30% operating condition, the main steam flow is about 330t / h. After adopting the deep peak-shaving and stable combustion operation system, the bypass main steam flow is about 48t / h, replacing the original first-stage extraction flow of about 12t / h, which can further reduce the turbine power generation load by about 3.8MW, ensuring the stable combustion of the boiler and the activity of the SCR catalyst under the deep peak-shaving operation condition while reducing the load rate by 1.1%.

[0021] The deep peak-shaving and stable combustion operation system of the power station utilizes part of the main steam heat to heat the boiler secondary air and increase the temperature of the boiler hot secondary air under the deep peak-shaving operation conditions, thereby ensuring stable combustion of the boiler under the deep peak-shaving operation conditions. At the same time, the steam after heating the boiler secondary air enters the No. 1 high-pressure heater of the steam turbine, which can increase the temperature of the feed water entering the boiler, thereby increasing the inlet flue gas temperature of the SCR reactor under the deep peak-shaving operation conditions of the boiler, ensuring the activity of the SCR catalyst under the deep peak-shaving operation conditions, and broadening the working range of the denitrification system under the deep peak-shaving operation conditions of the boiler. In addition, bypassing part of the main steam is also conducive to reducing the power generation load of the steam turbine, further realizing the deep peak-shaving of the steam turbine.

[0022] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principle of the present invention, and these improvements and modifications should also be regarded as within the protection scope of the present invention.

Claims

1. A deep peak load regulation and stable combustion operation system for a power station, characterized in that: It comprises a power station boiler (1), a steam turbine high-pressure cylinder (2), a steam turbine No. 1 high-pressure heater (3), a steam-flue gas heat exchanger (5), a steam turbine main steam bypass pipeline (7), a steam turbine first stage steam extraction pipeline (8), and a main steam regulating valve (9); The power station boiler (1) is divided into two paths through the main steam regulating valve (9), one of which is connected to the high-pressure cylinder (2) of the steam turbine, and the other is connected to the steam-flue gas heat exchanger (5) through the main steam bypass pipeline (7) of the steam turbine; The steam-flue gas heat exchanger (5) is connected to the steam turbine No. 1 high-pressure heater (3); the steam turbine high-pressure cylinder (2) is connected to the steam turbine No. 1 high-pressure heater (3) through a first section of the steam turbine extraction pipeline (8); the steam turbine No. 1 high-pressure heater (3) is connected to the power station boiler (1); The power station boiler (1) is used to send out main steam through the main steam regulating valve (9) so that the main steam enters the main steam bypass pipe (7) of the steam turbine, and enters the steam-flue gas heat exchanger (5) through the main steam bypass pipe (7) of the steam turbine to exchange heat with the boiler secondary air. The steam after cooling enters the first high-pressure heater (3) of the steam turbine through the first steam extraction pipe (8) of the steam turbine to heat the boiler feed water. The boiler feed water enters the power station boiler (1) to absorb heat and then enters the high-pressure cylinder (2) of the steam turbine through the main steam pipe.

2. The deep peak load regulation and stable combustion operation system of a power station according to claim 1 is characterized in that: It also includes a boiler secondary air system (6), through which the power station boiler (1) is connected to the steam-flue gas heat exchanger (5), so that the boiler secondary air is heated by part of the main steam in the steam-flue gas heat exchanger (5) and then re-enters the boiler secondary air system (6) to promote boiler combustion.

3. The deep peak load regulation and stable combustion operation system of a power station according to claim 1 is characterized in that: It also comprises an SCR reactor (4), which is connected to the power plant boiler (1) and is used to allow the flue gas to pass through the economizer outlet of the power plant boiler (1) and then enter the SCR reactor (4) for flue gas denitrification.

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