CN217715027U

CN217715027U - Secondary air large air box capable of reducing dust accumulation

Info

Publication number: CN217715027U
Application number: CN202222050324.9U
Authority: CN
Inventors: 刘兴; 李染生; 付喜亮; 刘贵喜; 孟浩; 赵凯; 孙利; 吉利特; 李万荣; 王茂林; 侯赟; 侯建军; 袁弘; 田志飞; 尹君; 郭江奔
Original assignee: Inner Mongolia Jingneng Shengle Thermoelectricity Co ltd
Current assignee: Inner Mongolia Jingneng Shengle Thermoelectricity Co ltd
Priority date: 2022-08-04
Filing date: 2022-08-04
Publication date: 2022-11-01
Anticipated expiration: 2032-08-04

Abstract

The utility model discloses a reduce accumulational overgrate air case of dust relates to coal-fired power generation technical field. The secondary air inlet pipe is provided with a secondary air main air pipe, the secondary air main air pipe is provided with a connecting air pipe, an air outlet end of the secondary air main air pipe is provided with a secondary air large air box, and both a burner nozzle and the secondary air large air box are provided with SOFA air boxes; the joint of the secondary air inlet pipe and the secondary air main air pipe, the joint of the secondary air main air pipe and the secondary air large air box, the joint of the connecting air pipe and a burner nozzle and the corner of the secondary air main air pipe are all arc-shaped; set up first guide plate in overgrate air main air hose, the connecting air pipe, a plurality of first guide plates all are circular-arcly, can dismantle fixed connection between first guide plate and overgrate air main air hose, the connecting air pipe. The beneficial effects of the utility model reside in that: the secondary air system structure of the pulverized coal fired boiler with tangential four corners is improved and optimized, and dust accumulation is reduced.

Description

Secondary air large air box capable of reducing dust accumulation

Technical Field

The utility model mainly relates to the technical field of coal-fired power generation, in particular to a secondary air large bellows capable of reducing dust accumulation.

Background

In a pulverized coal fired boiler with tangential firing at four corners, a secondary air box is an indispensable important component in a boiler combustion system, and is used for collecting air required by fuel combustion in a centralized manner and uniformly distributing the air to each combustor so as to ensure that the fuel is fully combusted in the boiler. However, in the actual operation process of the boiler, a large amount of fly ash is often found to be deposited in the secondary air big air box, which seriously affects the safe and economic operation of the boiler.

In the pulverized coal boiler, secondary air is introduced into a rotary air preheater at the tail part of the boiler by a fan to be heated. A large amount of flue gas generated by burning the pulverized coal passes through the flue gas side of the air preheater, the heat storage element absorbs the heat in the flue gas, and meanwhile, the fly ash particles in the flue gas are partially deposited on the heat storage element. When the heat storage element rotates to the air side, the heat can raise the temperature of the air to form hot air, and the hot air can also carry the fine fly ash particles on the heat storage element to enter the large air box through the secondary air main pipe.

After the fly ash particles enter the large air box, most fly ash particles enter a hearth along with secondary air through the burner, and only a small part of fly ash particles are deposited in the large air box. Although the proportion of deposited dust is less, the deposition thickness of the fly ash at the bottom of the large wind box can reach l-2m after the unit runs for a long time.

In the operation process of the boiler, if the accumulated dust in the large air box can not be cleaned in time, the airflow in the large air box can be seriously influenced. Partial fluid channels in the large air box are blocked, so that the airflow velocity distribution of secondary air at four corners of a hearth is uneven, the secondary air and pulverized coal airflow cannot be fully mixed, and pulverized coal combustion is insufficient. If the amount of fly ash carried by the secondary air flowing through part of the nozzles is greatly increased, the water cooling wall nearby the nozzles is also abraded.

In the search of related subjects, patent ZL202121776787.2 discloses a secondary air box and boiler system for preventing the large air box of a cyclone burner from depositing ash, which comprises an air box body, an ash collecting pipeline and a plurality of layers of partition plates, wherein the partition plates capable of dividing the interior of the air box body into a plurality of channels are arranged below each row of cyclones inside the air box body, a plurality of ash collecting funnels are arranged on the bottom surfaces of each layer of partition plates and the air box body, an ash conveying pipe penetrating through the partition plates and the bottom surface of the air box body is arranged at the bottom of each ash collecting funnel, a flap door is arranged on each ash conveying pipe, the ash collecting funnels on the bottom surface of the air box body are connected with the ash conveying pipe and the ash collecting pipeline, and the original secondary air box is modified to have ash conveying capacity. However, the structure of the secondary air box is greatly changed in the mode, the use cost is high, the occupied space is large, and the application range is narrow.

SUMMERY OF THE UTILITY MODEL

For solving the not enough of prior art, the utility model provides a reduce big bellows of accumulational overgrate air of dust, it improves the optimization to the overgrate air system structure of four corners tangential firing pulverized coal fired boiler, has reduced piling up of dust.

The utility model discloses a realize above-mentioned purpose, realize through following technical scheme:

a big secondary air bellow capable of reducing dust accumulation comprises a secondary air inlet pipe, wherein a main secondary air pipe is arranged on the secondary air inlet pipe, a connecting air pipe is arranged on the main secondary air pipe, a burner nozzle is arranged at the air outlet end of the connecting air pipe, a big secondary air bellow is arranged at the air outlet end of the main secondary air pipe, and SOFA bellows are arranged on the burner nozzle and the big secondary air bellow;

the joint of the secondary air inlet pipe and the secondary air main air pipe, the joint of the secondary air main air pipe and the secondary air large air box, the joint of the connecting air pipe and a burner nozzle and the corner of the secondary air main air pipe are all arc-shaped;

set up first guide plate in overgrate air total air pipe, the linking air pipe, first guide plate is located overgrate air total air pipe, the circular-arc corner position department of linking air pipe, every the first guide plate of circular-arc corner position department is a plurality of, and is a plurality of first guide plate all is circular-arc, can dismantle fixed connection between first guide plate and overgrate air total air pipe, the linking air pipe.

The first guide plates have the same distance.

And a grid is arranged at the air outlet end of the secondary air main air pipe.

And the inlet end of the connecting air pipe is provided with a second guide plate.

Contrast prior art, the beneficial effects of the utility model are that:

the utility model discloses a corner to the overgrate air system carries out the circular arc and improves to set up the guide plate in the pipeline, make the air velocity distribution who carries out big bellows even, the weight is even, has effectively slowed down the deposit of flying dust granule, and it is little to change overgrate air system part, and the guide plate position is adjustable, and it is nimble convenient to use, and is with low costs, and application scope is wide.

Drawings

FIG. 1 is a secondary air system structure of a conventional pulverized coal boiler with tangential firing at four corners;

FIG. 2 is a schematic structural view of the present invention;

FIG. 3 is a schematic view of the internal structure of the secondary air main duct of the present invention;

FIG. 4 is a schematic structural view in elevation of FIG. 3;

FIG. 5 is a schematic structural view of the outlet ends of the secondary air large bellows and the secondary air main air pipe of the utility model;

FIG. 6 is a schematic view of the connection structure of the connecting air pipe and the burner nozzle of the present invention;

FIG. 7 is a gas flow diagram of the overfire air system in the configuration of FIG. 1;

FIG. 8 is a graph of particle trajectories for the overfire air system in the configuration of FIG. 1;

FIG. 9 is a gas flow diagram of the structure of the present invention;

fig. 10 is a gas flow diagram of the structure of the present invention.

The reference numbers shown in the figures: 1. a secondary air inlet pipe; 2. a secondary air main air pipe; 3. connecting an air pipe; 4. a burner nozzle; 5. a secondary air large air box; 6. a SOFA air box; 7. a first baffle; 8. a grid; 9. a second baffle.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and specific embodiments. It should be understood that these examples are only for illustrating the present invention and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention can be made by those skilled in the art after reading the teaching of the present invention, and these equivalents also fall within the scope of the present invention.

The utility model discloses the standard part that uses in all can purchase from the market, and dysmorphism piece all can be customized according to the description with the record of drawing, and the concrete connected mode of each part all adopts conventional means such as ripe bolt, rivet, welding among the prior art, and simultaneously, in order to express clearly the relation of connection and theory of operation between each component, the description drawing adopts the mode of the sketch of mechanism's motion to arrange in order and draws, no longer details here.

As shown in the attached drawing, the main structure of the secondary air large air box for reducing dust accumulation comprises a secondary air inlet pipe 1, wherein a secondary air main air pipe 2 is arranged on the secondary air inlet pipe 1, a connecting air pipe 3 is arranged on the secondary air main air pipe 2, the figure 1 is the original structure of a secondary air system of a pulverized coal boiler with tangential combustion at four corners, and the secondary air system consists of a secondary air inlet pipeline, the secondary air main air pipe, the large air box, a burnout air box and burner nozzles. It can be seen from the figure that the secondary air enters the secondary air system and then enters the large air box through 3 90-degree elbows, and the secondary air entering the large air box distributes flow to the left and right two angles. Due to the structural characteristics of the secondary air main pipe and the large air box, airflow entering the large air box is not uniform when being distributed to the corners at two sides, so that the deposition amount of fly ash particles at the bottoms of the large air boxes at the corners is large. After the running time is longer, a large amount of fly ash is deposited to block a flow channel at the bottom of the large air box. A burner nozzle 4 is arranged at the air outlet end of the connecting air pipe 3, a secondary air large air box 5 is arranged at the air outlet end of the secondary air main air pipe 2, and SOFA air boxes 6 are arranged on the burner nozzle 4 and the secondary air large air box 5; the joint of the secondary air inlet pipe 1 and the secondary air main air pipe 2, the joint of the secondary air main air pipe 2 and the secondary air big air box 5, the joint of the connecting air pipe 3 and the burner nozzle 4 and the corner of the secondary air main air pipe 2 are all arc-shaped; set up first guide plate 7 in overgrate air total wind pipe 2, the connecting air pipe 3, first guide plate 7 is located overgrate air total wind pipe 2, connecting air pipe 3's circular-arc corner position department, every first guide plate 7 of circular-arc corner position department is a plurality of, and is a plurality of first guide plate 7 all is circular-arc, preferably, and deflector thickness is 10mm, and the deflector height is the same with overgrate air total wind pipe height, and the distance between deflector interval and guide plate and pipeline wall all equals, can dismantle fixed connection between first guide plate 7 and overgrate air total wind pipe 2, the connecting air pipe 3, be convenient for pull down, the adjusting position.

Optimally, the first guide plates 7 have the same distance, so that the air speed and the air volume can be more uniform in the pipeline flow, and the accumulation of fly ash is reduced.

Further, the air outlet end of the secondary air main duct 2 is provided with a grid 8, the original structure at this position is a 90-degree right-angle connection, as shown in fig. 5, the right-angle connection at this position is subjected to radian processing, and the radius of the circular arc can be 1.2m. Grid guide plates are additionally arranged before the circular arc, preferably nine grids are arranged in the transverse direction and the longitudinal direction, the grid intervals are the same, the thickness is 10mm, the width is 500mm, the accumulation of fly ash is reduced, and dust particles can be smoothly output.

Furthermore, the inlet end of the connecting air pipe 3 is provided with a second guide plate 9, so that the accumulation of fly ash is reduced, and the circulation of dust is facilitated.

Fig. 7 and 8 are gas flow diagrams and particle trajectory diagrams for the original configuration of the secondary air system. As can be seen from fig. 7, the gas forms a significant vortex at the bottom of the large airbox under the influence of the secondary air main. As can be seen from FIG. 8, the vortex formed by the gas at the bottom of the large windbox carries the fly ash particles to the bottom of the large windbox. The particles reach the bottom of the large windbox at a very low velocity and are easily deposited, and the larger the particles, the more pronounced the tendency to deposit.

Fig. 9 and 10 are gas flow diagrams and particle trajectory diagrams of the improved structure of the secondary air system. As can be seen from FIG. 9, after the structure improvement, the vortex area formed by the gas at the bottom of the big wind box is obviously improved. As can be seen from FIG. 10, the particles reaching the bottom of the large windbox are also significantly reduced, and therefore the deposition amount of the particles at the bottom of the large windbox is greatly reduced. And the particle sizes are different, and the particle trajectories are very similar.

Claims

1. The utility model provides a reduce big bellows of dust is piled up, includes overgrate air inlet pipe (1), its characterized in that: a secondary air main air pipe (2) is arranged on the secondary air inlet pipe (1), a connecting air pipe (3) is arranged on the secondary air main air pipe (2), a burner nozzle (4) is arranged at the air outlet end of the connecting air pipe (3), a secondary air large air box (5) is arranged at the air outlet end of the secondary air main air pipe (2), and SOFA air boxes (6) are arranged on the burner nozzle (4) and the secondary air large air box (5);

the joint of the secondary air inlet pipe (1) and the secondary air main air pipe (2), the joint of the secondary air main air pipe (2) and the secondary air big air box (5), the joint of the connecting air pipe (3) and the burner nozzle (4) and the corner of the secondary air main air pipe (2) are all arc-shaped;

set up first guide plate (7) in overgrate air total wind pipe (2), connecting air pipe (3), first guide plate (7) are located the circular-arc corner position department of overgrate air total wind pipe (2), connecting air pipe (3), every first guide plate (7) of circular-arc corner position department are a plurality of, and are a plurality of first guide plate (7) all are circular-arc, can dismantle fixed connection between first guide plate (7) and overgrate air total wind pipe (2), connecting air pipe (3).

2. The large secondary air bellow for reducing dust accumulation according to claim 1, wherein: the first guide plates (7) have the same distance.

3. A overfire air large windbox with reduced dust accumulation as claimed in claim 1, wherein: and a grid (8) is arranged at the air outlet end of the secondary air main air pipe (2).

4. A overfire air large windbox with reduced dust accumulation according to claim 1 or 2, wherein: and a second guide plate (9) is arranged at the inlet end of the connecting air pipe (3).