Multifunctional ejection type extended flue device for power plant boiler

Abstract

The present application relates to the field of coal-fired steam boiler, and more particularly to a multifunctional injection type extended flue device for power plant boiler, which comprises a vertical flue, a first ash bucket, a horizontal gradually expanding flue, a second ash bucket and an ascending flue connected in sequence, a dust catching device and a jet device are arranged at the front and back of the horizontal gradually expanding flue respectively, the dust catching device comprises a plurality of shunt supports, each shunt support is connected with a dust catching velvet at the bottom, the jet device comprises a plurality of jet pipes, a plurality of injection holes are formed at the bottom of the side of the jet pipe away from the shunt support, a single through central hole is arranged in the jet pipe, the present application collects fly ash twice through the double ash buckets, cooperates with the deceleration effect of the gradually expanding flue, and then uses the adsorption effect of the velvet and the swing of the velvet caused by the air pressure difference to shake off and collect the fly ash into the jet, so that the fly ash collection efficiency of the traditional single ash bucket flue is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal-fired steam boilers, in particular to a multifunctional ejection type extended flue device for power plant boilers. BACKGROUND

[0002] The way of W-shaped flame boiler burning low-quality coal well solves the problem of energy supply, but coal combustion also generates a large amount of pollutants such as NOx and coal ash dust. Selective catalytic reduction (SCR) denitration system is widely used in coal-fired power plants to reduce NOx emissions. Due to the requirement of denitration flue gas temperature, the SCR reactor is mostly arranged in the flue between the economizer and the air preheater. The flue gas in this flue area carries a large amount of fly ash particles. The wear of the SCR catalyst caused by the large particle fly ash in the flue gas, the catalyst blockage caused by the deposition of fly ash, and the poisoning of the catalyst caused by the alkali metal in the fly ash will cause the performance of the SCR catalyst to decrease seriously. The catalyst is the core of the SCR denitration process, and the decrease in the performance of the SCR catalyst will cause problems such as decrease in the denitration efficiency of the system and increase in ammonia escape. Therefore, how to efficiently remove ash, especially large particle fly ash particles, before the flue gas enters the SCR denitration reactor is of great significance to prevent catalyst blockage and wear and even the economic and safe operation of the entire boiler unit.

[0003] The fly ash capture efficiency of the traditional single-ash-dump flue is low, and the vertically entering flue gas still has a high kinetic energy after one bend, so that the flue gas discharged upward after the subsequent second bend still has a high content of fly ash particles. SUMMARY

[0004] Therefore, it is necessary to provide a multifunctional ejection type extended flue device for power plant boilers in view of the problems of the prior art.

[0005] To solve the problems of the prior art, the technical scheme adopted by the present application is as follows:

[0006] A multifunctional ejection type extended flue device for power plant boilers is arranged between an economizer and an air preheater, and comprises:

[0007] The flue body is composed of a vertical flue, a horizontal gradually expanding flue and an upward flue connected in sequence. The small end of the horizontal gradually expanding flue is provided with a first ash dump at the bottom of the vertical flue, and the large end of the horizontal gradually expanding flue is provided with a second ash dump at the bottom of the upward flue.

[0008] The dust capturing device is arranged in the horizontal gradually expanding flue close to one end of the vertical flue. The dust capturing device comprises a plurality of flow splitting supports distributed at equal intervals in the longitudinal direction. Each flow splitting support is arranged horizontally and has a dust capturing velvet connected to the bottom thereof. One end of the dust capturing velvet is fixedly connected to one end of the flow splitting support close to the vertical flue.

[0009] The jet flow device is arranged in the horizontal gradually expanding flue close to one end of the ascending flue, and the jet flow device comprises a plurality of jet flow pipes which are longitudinally and equidistantly distributed, each jet flow pipe is located below the rear end of the corresponding flow distribution support, and a plurality of injection holes which are inclined to the inner wall of the second ash bucket are arranged on the side bottom of each jet flow pipe away from the flow distribution support, and all the injection holes are equidistantly distributed along the length direction of the jet flow pipe.

[0010] Each jet flow pipe is provided with a single-pass central hole which extends to the outside of one end along the length direction of the jet flow pipe, the single-pass central hole sequentially passes through all the injection holes, and the same end of all the single-pass central holes is communicated to the flue at the outlet of the economizer through an air extraction mechanism.

[0011] Preferably, the top wall of the horizontal gradually expanding flue is arranged in a horizontal state, and the bottom wall is arranged in an inclined state, and the lower end of the bottom wall extends towards the second ash bucket.

[0012] Preferably, the front end of the flow distribution support is fixedly provided with a wind baffle which extends downwardly and inclines towards the direction of the second ash bucket, and one end of the dust catching velvet is fixedly connected with the wind baffle.

[0013] Preferably, the front end of each flow distribution support is fixedly provided with a blow-off flat nozzle which is arranged downwardly and inclines rearwardly, and all the blow-off flat nozzles are connected with the ion fan system.

[0014] Preferably, both sides of each injection hole are provided with negative suction holes which are connected with the injection holes at a “Y” type angle.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] Firstly, the present application adds an ash bucket before the ascending flue, and the front ash bucket and the added ash bucket cooperate to collect fly ash twice, so that the fly ash collection efficiency of the traditional single-ash-bucket flue is effectively improved.

[0017] Secondly, the present application further reduces the flow rate of flue gas by arranging the gradually expanding flue, so that the fly ash particles passing through are more easily collected.

[0018] Thirdly, the present application arranges the jet flow mechanism in the gradually expanding flue, so that more flue gas can be accelerated into the second ash bucket through the jet flow impact and the negative suction hole.

[0019] Fourthly, the present application further improves the collection efficiency of fly ash particles by arranging the velvet with additional electric charges, and the fly ash particles collected and stopped are shaken off by the pressure difference principle, so as to facilitate subsequent jet flow collection. BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 is a plane structure schematic view of the present application;

[0021] Fig. 2 is the schematic diagram of the cooperation process of the dust catching cloth and the jet pipe of the present application;

[0022] Fig. 3 is the plane section view of the jet pipe of the present application at the position of the injection hole;

[0023] The figure marks are: 1-vertical flue; 2-horizontal gradually expanding flue; 3-rising flue; 4-first ash bucket; 5-second ash bucket; 6-dust catching device; 7-shunt support; 8-dust catching cloth; 9-jet device; 10-jet pipe; 11-injection hole; 12-single pass central hole; 13-wind baffle; 14-blowing flat nozzle; 15-negative suction hole. Embodiment

[0024] In order to further understand the features, technical means and specific purposes and functions achieved by the present application, the present application is described in further detail below in combination with the drawings and specific embodiments.

[0025] Referring to Figs. 1 to 3 , a multifunctional injection type expanding flue device for power plant boiler is arranged between the economizer and the air preheater, comprising:

[0026] The flue body is composed of a vertical flue 1, a horizontal gradually expanding flue 2 and a rising flue 3 connected in sequence, the small end of the horizontal gradually expanding flue 2 is provided with a first ash bucket 4 at the bottom of the vertical flue 1, and the large end of the horizontal gradually expanding flue 2 is provided with a second ash bucket 5 at the bottom of the rising flue 3;

[0027] The dust catching device 6 is arranged in the horizontal gradually expanding flue 2 near one end of the vertical flue 1, the dust catching device 6 comprises a plurality of shunt supports 7 distributed at equal intervals in the longitudinal direction, each shunt support 7 is arranged horizontally and has a dust catching cloth 8 connected at the bottom, one end of the dust catching cloth 8 is fixedly connected to one end of the shunt support 7 near the vertical flue 1;

[0028] The jet device 9 is arranged in the horizontal gradually expanding flue 2 near one end of the rising flue 3, the jet device 9 comprises a plurality of jet pipes 10 distributed at equal intervals in the longitudinal direction, each jet pipe 10 is located below the rear end of the corresponding shunt support 7, and a plurality of injection holes 11 inclined towards the inner wall of the second ash bucket 5 are formed at the bottom of the side of each jet pipe 10 away from the shunt support 7, all the injection holes 11 are distributed at equal intervals along the length direction of the jet pipe 10;

[0029] Each jet pipe 10 is provided with a single-pass central hole 12 extending to one end outside along the length direction of the jet pipe 10, the single-pass central hole 12 sequentially passes all the injection holes 11, and the same end of all the single-pass central holes 12 is communicated to the flue at the economizer outlet through an air extraction mechanism.

[0030] The ash-containing flue gas enters through the vertical flue 1, is discharged from the rising flue 3 after passing through the horizontally gradually expanding flue 2, and is bent at the first ash hopper 4 and the second ash hopper 5 in the process, thereby reducing the flow rate and kinetic energy of the ash-containing flue gas, and facilitating the falling of dust particles into the first ash hopper 4 and the second ash hopper 5 to be captured.

[0031] During the process of passing through the horizontally gradually expanding flue 2, the ash-containing flue gas is effectively reduced in flow rate due to the gradually increasing diameter of the horizontally gradually expanding flue 2, and when the particles pass through the first ash hopper 4 and the second ash hopper 5, they are more easily captured due to the reduced speed.

[0032] After the ash-containing flue gas passes through the dust capturing device 6, it is uniformly dispersed by all the equally spaced flow splitting supports 7, and the dispersed flue gas passes from below each dust capturing velvet 8. According to Bernoulli's theorem, the air flow rate is faster and the pressure is smaller below the dust capturing velvet 8 at this time, and the air flow rate is slower and the pressure is larger above the dust capturing velvet 8, so the dust capturing velvet 8 will float and swing downward. With the continuous up-and-down floating and swinging of the dust capturing velvet 8, the flue gas passing between adjacent two flow splitting supports 7 can come into contact with the dust capturing velvet 8. The dust capturing velvet 8 is single-sided velvet, and the velvet surface is arranged upward, with dense, level, upright and shiny pile, which can capture dust particles in the flue gas. The captured dust particles are scattered in the space above the second ash hopper 5 with the continuous swinging of the dust capturing velvet 8, and the dust-containing flue gas in this area is hit by the jet pipe 10 against the rear wall of the second ash hopper 5 for collection. After the flue gas is ejected from the injection hole 11, the flue gas in the space around the jet path will also be drawn into the jet air under the action of the pressure difference.

[0033] The device makes the dust-containing flue gas first reduce in speed and kinetic energy when passing through the first ash hopper 4, and then further reduces in speed and kinetic energy in the process of entering the horizontally gradually expanding flue 2 with gradually increasing cross section, which is also beneficial to the re-speed reduction and capture of particles when passing through the dust capturing velvet 8. The captured particles are shaken and fallen by the dust capturing velvet 8, and then are hit by the rear jet pipe 10 together with the surrounding flue gas against the rear wall of the second ash hopper 5, thereby greatly improving the capture efficiency of the second ash hopper 5.

[0034] The top wall of the horizontal gradually expanding flue 2 is arranged horizontally, the bottom wall is arranged obliquely, and the lower end of the bottom wall extends towards the second hopper 5. The jet device 9 is arranged on the expansion slope of the horizontal gradually expanding flue, the flue gas at the front end of the device is sucked into the single-through central hole 12 by the air suction mechanism, and is jetted towards the rear wall of the second hopper 5 through the injection hole 11, so that more flue gas particles can enter the second hopper 5.

[0035] The front end of the shunt support 7 is fixedly provided with a wind deflector 13 extending obliquely downwards towards the second hopper 5, and one end of the dust catching velvet 8 is fixedly connected with the wind deflector 13. The obliquely arranged wind deflector 13 is beneficial to flue gas impact, and after the airflow passes through the wind deflector 13, the airflow is gathered towards the dust catching velvet 8 under the effect of the spoiler, so that the dust-containing flue gas can more fully and quickly contact the dust catching velvet 8, and the flying dust collection efficiency is improved.

[0036] The front end of each shunt support 7 is fixedly provided with a wind supply flat nozzle 14 arranged obliquely downwards towards the rear, and all the wind supply flat nozzles 14 are connected with the ion fan system. In order to further strengthen the particle collection effect of the dust catching velvet 8, the generated ions are blown to the bottom surface of the dust catching velvet 8 through the wind supply flat nozzle 14 by the ion fan, so that the dust catching velvet 8 is attached with the ions, and the flying dust particles can be better adsorbed and collected.

[0037] Both sides of each injection hole 11 are provided with negative suction holes 15 connected at a “Y” type angle, the flying dust particles after being collected and shaken off and scattered at a reduced speed enter the jet pipe 10 through the negative suction holes 15 and are finally ejected from the jet holes together with the flue gas at the front end and are collected by impacting the rear wall of the second hopper 5, and the setting of the negative suction holes 15 accelerates the directional jet efficiency of the dust in the surrounding space.

[0038] The above embodiments only express one or several embodiments of the present application, the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A multi-functional, ejector-type, extended flue gas duct device for a power plant boiler, provided between a coal economizer and an air preheater, characterized by, The utility model relates to a flue body, which is composed of a vertical flue (1), a horizontal gradually expanding flue (2) and an ascending flue (3) connected in sequence, wherein the small end of the horizontal gradually expanding flue (2) is provided with a first ash bucket (4) at the bottom of the vertical flue (1), and the large end of the horizontal gradually expanding flue (2) is provided with a second ash bucket (5) at the bottom of the ascending flue (3); a dust catching device (6) is arranged in the horizontal gradually expanding flue (2) near the end of the vertical flue (1), the dust catching device (6) comprises a plurality of longitudinal equally spaced flow distribution supports (7), each flow distribution support (7) is arranged horizontally and is connected with a dust catching velvet (8) at the bottom, one end of the dust catching velvet (8) is fixedly connected to the end of the flow distribution support (7) near the vertical flue (1); a jet device (9) is arranged in the horizontal gradually expanding flue (2) near the end of the ascending flue (3), the jet device (9) comprises a plurality of longitudinal equally spaced jet pipes (10), each jet pipe (10) is located below the rear end of the corresponding flow distribution support (7), and the bottom of the side of each jet pipe (10) away from the flow distribution support (7) is provided with a plurality of injection holes (11) inclined to the inner wall of the second ash bucket (5), all the injection holes (11) are equally spaced along the length direction of the jet pipe (10); wherein each jet pipe (10) is provided with a single-pass central hole (12) extending to the outside of one end along the length direction, the single-pass central hole (12) passes through all the injection holes (11) in sequence, and the same end of all the single-pass central holes (12) is communicated to the flue at the outlet of the economizer through a gas suction mechanism. The top wall of the horizontal gradually expanding flue (2) is arranged in a horizontal state, and the bottom wall is arranged in an inclined state, and the lower end of the bottom wall extends towards the second ash bucket (5). The front end of the flow distribution support (7) is fixedly provided with a wind deflector (13) inclined downward towards the direction of the second ash bucket (5), and one end of the dust catching velvet (8) is fixedly connected to the wind deflector (13). The front end of each flow distribution support (7) is fixedly provided with an air supply flat nozzle (14) inclined downward towards the rear, and all the air supply flat nozzles (14) are connected with an ion fan system. Both sides of each injection hole (11) are provided with negative suction holes (15) connected at a "Y" type angle.

2. A multi-functional, ejector-type, extended flue gas duct device for a power plant boiler according to claim 1, characterized in that, ​ 3. The multi-functional, ejector-type, extended flue gas duct apparatus for use in a utility boiler according to claim 1, characterized by, ​ 4. A multi-functional, ejector-type extended flue gas duct device for a power plant boiler according to claim 3, characterized in that, ​ 5. The multi-functional, ejector-type, extended flue gas duct apparatus for use in a utility boiler according to claim 1, characterized by, ​

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