CN219624026U

CN219624026U - Primary air concentration separation cyclone pulverized coal burner

Info

Publication number: CN219624026U
Application number: CN202320267989.7U
Authority: CN
Inventors: 赵立鹏; 岳磊; 李勇; 施宪明; 王建平
Original assignee: Taishan Group Co ltd
Current assignee: Taishan Group Co ltd
Priority date: 2023-02-17
Filing date: 2023-02-17
Publication date: 2023-09-01
Anticipated expiration: 2033-02-17

Abstract

The utility model particularly relates to a primary air concentration separation cyclone pulverized coal burner which comprises a main burner, a primary overfire air nozzle and a secondary overfire air nozzle, wherein the main burner is fixed on the side surface of a boiler water-cooled wall, the primary overfire air nozzle and the secondary overfire air nozzle are horizontally fixed on the top of the boiler water-cooled wall, the main burner comprises a central air pipe, a primary air channel, a circulating air channel, an inner secondary air channel and an outer secondary air channel, the primary air channel is sleeved outside the central air pipe, the circulating air channel and the inner secondary air channel are sleeved outside the primary air channel, and the outer secondary air channel is arranged on one side of the inner secondary air channel and communicated with the primary air channel. Through air staged combustion and full utilization of natural gas, the generation amount of nitrogen oxides is reduced on the premise of not affecting the original combustion efficiency and boiler performance of the coal-fired boiler, the emission of the nitrogen oxides is effectively reduced, and the environmental protection requirement is met.

Description

Primary air concentration separation cyclone pulverized coal burner

Technical Field

The utility model relates to the technical field of pulverized coal burners, in particular to a primary air concentration separation cyclone pulverized coal burner.

Background

China is a country which takes coal as a main energy source, wherein the coal accounts for 75% of primary energy sources, and more than 84% of the primary energy sources are utilized by a combustion method. Nitrogen oxides (NOx) in the exhaust gases released by the combustion of coal are one of the main sources of pollution responsible for atmospheric pollution. With the increasing requirements of China on the emission of nitrogen oxides of coal-fired boilers, the low NOx combustion technology is rapidly developed in recent years. However, due to technical differences of manufacturers, the problems of poor combustion stabilizing capability, poor burnout, high NOx emission, coking and the like exist.

Disclosure of Invention

The utility model aims to provide a primary air concentration separation cyclone pulverized coal burner, which is used for solving the problems of low pulverized coal burnout rate, poor combustion stability, larger or smaller burnout air position from a main burner, coking at a burnout air nozzle, high NOx emission and the like of the conventional industrial pulverized coal boiler.

The utility model provides a primary air concentration separation cyclone pulverized coal burner which comprises a main burner, a primary over-fire air nozzle and a secondary over-fire air nozzle, wherein the main burner is fixed on the side surface of a boiler water-cooled wall, the primary over-fire air nozzle and the secondary over-fire air nozzle are horizontally fixed on the top of the boiler water-cooled wall, the main burner comprises a central air pipe, a primary air duct, a circulating air channel, an inner secondary air channel and an outer secondary air channel, the primary air duct is sleeved outside the central air pipe, the circulating air channel and the inner secondary air channel are sleeved outside the primary air duct, the outer secondary air channel is arranged on one side of the inner secondary air channel and communicated with the primary air duct, the primary air duct comprises a primary air connecting flange, a primary air pipe, a concentrator and a tooth-shaped structure, the concentrator is arranged in the primary air pipe, the tooth-shaped structure is positioned at the outlet of the primary air nozzle, one end of the primary air pipe is connected with the primary air connecting flange, and the side wall of the primary air pipe is connected with the primary air inlet flange.

Preferably, a secondary air cyclone is arranged in the inner secondary air channel, and an outer secondary air cyclone is arranged in the outer secondary air channel.

Preferably, the distance between the primary over-fire air nozzle and the main burner is 3000-4000mm, and a plurality of primary over-fire air nozzles are arranged, and each primary over-fire air nozzle is provided with a regulating air door.

Preferably, the distance between the secondary over-fire air nozzle and the primary over-fire air nozzle is 500-2000mm, and a plurality of secondary over-fire air nozzles are arranged, and each secondary over-fire air nozzle is provided with a regulating air door.

Preferably, the primary over-fire air nozzle and the secondary over-fire air nozzle have the same structure and respectively comprise a reducing nozzle, a sealing box, an over-fire air inlet and a regulating air door, wherein the reducing nozzle is fixed on a boiler water-cooled wall and is communicated with the sealing box, the over-fire air inlet is connected to the other side of the sealing box, and the regulating air door is fixed on one side of the over-fire air inlet.

The beneficial effects of the utility model are as follows:

through the characteristics of fuel staged combustion and fully utilizing air staged combustion, the method can reduce the generation amount of nitrogen oxides to a larger extent on the premise of not affecting the original combustion efficiency and boiler performance of the coal-fired boiler, effectively reduce the emission of the nitrogen oxides under the condition of low cost, and meet the requirement of environmental protection emission. The primary air duct is provided with a concentrator, and partial pulverized coal concentration deviation combustion is formed at the pulverized coal nozzle by adopting an axial concentration separation design, so that the heating rate of concentrated-phase pulverized coal and the precipitation amount of volatile matters are improved, and the generation of NOx in the initial stage of combustion is controlled; the primary air outlet is designed into a tooth-shaped structure to play a role in stable combustion.

Drawings

Fig. 1: the whole structure of the primary air concentration separation cyclone pulverized coal burner is schematically shown,

fig. 2: the main burner is schematically shown in its structure,

fig. 3: the structure of the primary air duct is schematically shown,

fig. 4: the structure of the tooth-shaped structure is schematically shown,

fig. 5: the structure schematic diagram of the primary over-fire air nozzle and the secondary over-fire air nozzle.

The marks in the figure: the primary burner 1, the primary overfire air nozzle 2, the secondary overfire air nozzle 3, the central air duct 11, the primary air duct 12, the circulating air duct 13, the inner secondary air duct 14, the outer secondary air duct 15, the primary air connecting flange 121, the primary air inlet flange 122, the primary air duct 123, the concentrator 124, the tooth structure 125, the reducing nozzle 21, the seal box 22, the overfire air inlet 23 and the damper 24.

Detailed Description

The technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are only some embodiments of the present utility model, but not all embodiments, and all other embodiments obtained by those skilled in the art without making any inventive effort based on the embodiments of the present utility model are within the scope of protection of the present utility model.

Examples

As shown in fig. 1-5, the primary air concentration separation cyclone pulverized coal burner provided in this embodiment includes a main burner 1, a primary overfire air nozzle 2 and a secondary overfire air nozzle 3, the main burner 1 is fixed on the side surface of a boiler water-cooled wall 4, the primary overfire air nozzle 2 and the secondary overfire air nozzle 3 are horizontally fixed on the top of the boiler water-cooled wall 4, the main burner 1 includes a central air duct 11, a primary air duct 12, a circulating air duct 13, an inner secondary air duct 14 and an outer secondary air duct 15, the primary air duct 12 is sleeved outside the central air duct 11, the circulating air duct 13 and the inner secondary air duct 14 are sleeved outside the primary air duct 12, the outer secondary air duct 15 is arranged on one side of the inner secondary air duct 14 and is communicated with the primary air duct 12, the primary air duct 12 includes a primary air connection flange 121, a primary air inlet flange 122, a primary air duct 123, a concentrator 124 and a tooth-shaped structure 125, the tooth-shaped structure is disposed in the primary air duct 123, one end of the primary air duct is connected with the primary air inlet flange 123, and the primary air duct 122 is connected with the side wall of the primary air duct 122.

As a preferred implementation of this embodiment, the secondary air cyclone is disposed in the inner secondary air duct 14, and the outer secondary air cyclone is disposed in the outer secondary air duct 15.

As a preferred implementation manner of the embodiment, the distance between the primary over-fire air nozzle 2 and the main burner 1 is 3000-4000mm, and a plurality of primary over-fire air nozzles 2 are arranged, and each primary over-fire air nozzle 2 is provided with a regulating air door.

As a preferred implementation manner of the embodiment, the distance between the secondary over-fire air nozzle 3 and the primary over-fire air nozzle 2 is 500-2000mm, and a plurality of secondary over-fire air nozzles 3 are arranged, and each secondary over-fire air nozzle 3 is provided with a regulating air door. The primary over-fire air nozzle 2 and the secondary over-fire air nozzle 3 have the same structure and respectively comprise a reducing nozzle 21, a sealing box 22, an over-fire air inlet 23 and a regulating air door 24, each primary over-fire air nozzle 2 and each secondary over-fire air nozzle 3 are composed of a plurality of reducing nozzles 21, the reducing nozzles 21 are welded on a film type wall flat steel opening of a boiler water wall, a traditional over-fire air film type wall yielding pipe is not arranged at the position, and the sealing is not performed by using a heat insulation material, so that coking is avoided. One side of the sealing box 22 is connected with the reducing nozzle 21, the over-fire air inlet 23 is connected with the other opposite side of the sealing box 22, and the air damper 24 is fixed on one side of the over-fire air inlet 23.

The primary air duct is provided with a concentrator, and partial pulverized coal concentration deviation combustion is formed at the pulverized coal nozzle by adopting an axial concentration separation design, so that the heating rate of concentrated-phase pulverized coal and the precipitation amount of volatile matters are improved, and the generation of NOx in the initial stage of combustion is controlled; the primary air outlet is designed into a tooth-shaped structure to play a role in stable combustion.

The circulating air is flue gas recirculation air, and a part of low-temperature flue gas is extracted and directly fed into the boiler, so that the combustion temperature can be reduced, the oxygen concentration is reduced, and the emission concentration of NOx is further reduced. The internal secondary air is rotational flow air, and a small amount of air is supplied from the main burner in the pre-combustion stage of pulverized coal, so that fuel is combusted under the anoxic fuel-rich combustion condition. The outer secondary air is low-swirl air, oxygen required by fuel combustion is fed far away from a certain distance, the flame is wrapped to prevent the flame from scouring the water-cooled wall of the boiler, and at the moment, the excessive air coefficient alpha <1 in the first-stage combustion zone is reduced, so that the combustion speed and the temperature level in the combustion zone are reduced. Therefore, not only the combustion process is retarded, but also the reaction rate of generating NOx is reduced in the reducing atmosphere, and the amount of NOx generated in this combustion is suppressed. The primary over-fire air nozzle is used for feeding the rest air quantity of about 15%, and the air excess coefficient alpha of the primary over-fire air area is slightly larger than 1, so that the low excess air burns, the coal dust is over-fire, the carbon content of fly ash is reduced, and the generation of nitrogen oxides is inhibited. The secondary over-fire air nozzle is used for feeding the rest 15% of air quantity, and the pulverized coal is completely combusted under the condition that the air excess coefficient alpha of the secondary over-fire air area is larger than 1.

The application process adopts the following method for reducing nitrogen oxides: 1. spraying air-separated mixture from main burner 1 to burn, and supplying air through main burner, the air quantity is about 70%, and under the condition that air excess coefficient alpha is less than 1, reducing atmosphere is formed, so that the discharge quantity of nitrogen oxide is reduced by 90%; 2. the rest 15% of air quantity is fed through a primary over-fire air nozzle 2, and the injection speed of the over-fire air is more than 45m/s; the air excess coefficient alpha of the primary over-fire air area is slightly larger than 1, so that the low excess air burns, the coal dust is over-fire, the carbon content of fly ash is reduced, and the generation of nitrogen oxides is inhibited. 3. The rest 15% of air quantity is fed through a secondary over-fire air nozzle 3, and the injection speed of the over-fire air is more than 45m/s; and the pulverized coal is completely combusted under the condition that the air excess coefficient alpha of the secondary over-fire air area is larger than 1. The parameters can be adjusted according to actual conditions, so that combustion and low nitrogen reach the most reasonable range.

Although embodiments of the present utility model have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the utility model, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A primary air concentration separation cyclone pulverized coal burner is characterized in that: including main burner, one-level over-fire air spout, second grade over-fire air spout, main burner is fixed in the side of boiler water-cooled wall, one-level over-fire air spout, second grade over-fire air spout level are fixed in the top of boiler water-cooled wall, main burner includes central tuber pipe, primary air duct, circulation wind passageway, interior overgrate air passageway, outer overgrate air passageway, the outside at central tuber pipe is established to the cover of primary air duct, circulation wind passageway, interior overgrate air passageway cover are established outside the primary air duct, outer overgrate air passageway sets up in overgrate air passageway one side, communicates the primary air duct, the primary air duct includes primary air flange, primary air inlet flange, primary air pipe, concentrator, profile structure is located primary air spout exit, primary air flange is connected to primary air pipe one end, primary air pipe lateral wall connection primary air inlet flange.

2. The primary air concentration separation cyclone pulverized coal burner as claimed in claim 1, wherein: the inner secondary air channel is internally provided with a secondary air cyclone, and the outer secondary air channel is internally provided with an outer secondary air cyclone.

3. The primary air concentration separation cyclone pulverized coal burner as claimed in claim 1, wherein: the distance between the primary over-fire air nozzle and the main burner is 3000-4000mm, a plurality of primary over-fire air nozzles are arranged, and each primary over-fire air nozzle is provided with a regulating air door.

4. The primary air concentration separation cyclone pulverized coal burner as claimed in claim 1, wherein: the distance between the secondary over-fire air nozzle and the primary over-fire air nozzle is 500-2000mm, a plurality of secondary over-fire air nozzles are arranged, and each secondary over-fire air nozzle is provided with a regulating air door.

5. The primary air concentration separation cyclone pulverized coal burner as claimed in claim 1, wherein: the primary over-fire air nozzle and the secondary over-fire air nozzle have the same structure and respectively comprise a reducing nozzle, a sealing box, an over-fire air inlet and a regulating air door, wherein the reducing nozzle is fixed on a boiler water-cooled wall and is communicated with the sealing box, the over-fire air inlet is connected to the other side of the sealing box, and the regulating air door is fixed to one side of the over-fire air inlet.