JPH11304114A - Lean/rich combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lean/rich combustor in which combustion is stabilized while suppressing generation of NOx furthermore. SOLUTION: A plurality of rich burners 3 having, on one end side thereof, an elongated burner port plane 6 provided with a rich burner port section 7 for ejecting and burning rich mixture gas generated from a section 9 for mixing fuel gas an combustion air are juxtaposed at an interval in the breadthwise direction of the burner port plane 6 wherein lean mixture gas of fuel gas an combustion air is fluidized among the rich burners 3 to be ejected from a lean burner port 14 disposed between the burner port planes 6 of the rich burners 3 and burnt. In such a lean/rich combustor, planar cover bodies 20 covering the opposite side faces of the rich burner 3 in the breadthwise direction of the burner port plane 6 are held by the rich burner 3 such that lean mixture gas is fluidized between adjacent cover bodies 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rich mixing section which has an elongated flame opening face at one end and mixes fuel gas and combustion air to generate a rich mixture. A plurality of rich burners provided on the flame face with a rich flame port for ejecting and burning the rich mixture generated in the section, are arranged side by side at intervals in the width direction of the flame face, A light mixture of fuel gas and combustion air flows between the rich burners, and a light mixture is ejected from an elongated thin flame opening provided between the flame surfaces of the rich burner. The present invention relates to a lean burn device configured to burn.

[0002]

2. Description of the Related Art The above-described concentration combustion apparatus has a plurality of concentration burners arranged side by side at predetermined intervals to reduce the cost without specially providing a light burner for injecting a lean mixture. The fuel gas is burned at a large air mixing ratio as a whole, so that stable combustion can be performed while minimizing the generation of NOx as a nitrogen oxide.
Then, in the conventional rich-burn combustion apparatus, the lean air-fuel mixture flows while contacting both side surfaces in the width direction of the flame surface of the rich burner (for example, see Japanese Patent Application Laid-Open No. Hei 7-180815). .

[0003]

However, in a conventional rich / lean combustion apparatus, the rich mixing portion of the rich burner is usually formed in a shape protruding toward the flowing lean air-fuel mixture.
In order to further suppress the generation of NOx, for example, if the ratio of the lean mixture to the rich mixture is increased while increasing the air mixing ratio of the entire fuel gas, the flow rate of the lean mixture is increased, and the lean mixture is increased. Flowed while contacting the rich burner, the flow of the lean mixture became unstable, and the combustion state sometimes became unstable.

Therefore, the present invention has been made in view of such a point, and an object of the present invention is to reduce the cost by using a burner for darkness as a burner for lightness and to reduce NOx.
It is an object of the present invention to provide a light-and-dark combustion apparatus that can perform stable combustion while further suppressing the generation of gas.

[0005]

To achieve this object, according to the first aspect of the present invention, a plate-like cover body for covering both side surfaces of a dark burner in a width direction of a flame opening surface is provided. , Provided so as to be held by a thick burner, so that a light mixture flows between the cover bodies adjacent to each other. Therefore, it is not necessary to provide a light burner, and the cost can be reduced. Further, by forming the cover body held by the rich burner into a shape corresponding to the flow of the light mixture, the light mixture can be reduced. Since unevenness that hinders the smooth flow of the air-fuel mixture can be eliminated, the flow of the air-fuel mixture can be stabilized even if the flow rate of the air-fuel mixture is increased to suppress the generation of NOx. , And stable combustion can be performed.

According to the second aspect of the present invention, since the cover body is provided in contact with the side surface of the rich burner, a useless space is provided between the cover body and the side surface of the rich burner. Without this, the size of the entire device can be reduced in the width direction of the flame surface, and the size of the device can be reduced.

According to the third aspect of the present invention, a mixing promoting portion is provided at an intermediate portion of the cover body in the flow direction of the lean air-fuel mixture to protrude toward the flowing lean air-fuel mixture to promote the mixing of the lean air-fuel mixture. As the mixture is lightly mixed in the mixing promoting section, the sufficiently mixed light mixture can be blown out from the light flame port, and more stable combustion can be performed. Becomes

According to the fourth aspect of the present invention, since the mixing promoting portion is constituted by the bulging portion integrally formed with the cover, it is not necessary to provide the mixing promoting portion separately from the cover.
Since it is possible to reduce the cost, and furthermore, it is possible to insert the thick mixing portion into the space inside the bulging portion and to form the cover body in a shape corresponding to the thick burner and to provide the cover with the thick burner. The size of the entire device can be reduced in the width direction of the mouth surface, and the size of the device can be reduced.

According to the fifth aspect of the present invention, a plurality of holding portions for holding the thick burner are provided in a rectangular cylindrical casing for housing the thick burner, and the plurality of thick burners are provided by the plurality of holding portions. In a state in which the light mixture flows in the space formed by the cover body and the casing in a state in which The burners are arranged side by side at intervals in the width direction of the flame outlet face, and a light air-fuel mixture can be caused to flow between the thick burners, thereby facilitating the manufacturing operation of the apparatus.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A lean combustion apparatus according to the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 4, the concentration combustion apparatus includes a burner case 1 and a rectangular tubular box-shaped frame 2 as an internal casing in the burner case 1, and a plurality of burners. The flat sheet metal thickening burners 3 are juxtaposed at predetermined intervals while being held by the plurality of holding portions 2a of the box-shaped frame 2, and are accommodated in the box-shaped frame 2. I have. A fan 4 for supplying combustion air is provided below the burner case 1 and has a discharge port formed between the bottom of the burner case 1 and the bottom of the box-shaped frame 2. It communicates with the air chamber 5.

The thick burner 3 is formed by bending a series of plate members and blows out and burns a rich air-fuel mixture having a low air mixing ratio. Rich flame openings 7 for ejecting the air-fuel mixture and non-flame openings 8 that do not eject the rich air-fuel mixture are alternately arranged at substantially equal intervals along the longitudinal direction of the flame opening surface. The dense flame outlet 7 is constituted by a plurality of slit-shaped flame holes 7a.
The rich burner 3 is provided with a rich mixing section 9 communicating with each rich flame port 7 in a state of bulging to both sides in the width direction of the flame port face 6. A concentration inlet 10 for introducing gas and combustion air is provided. A plurality of such darkening burners 3 are arranged side by side at intervals in the width direction of the flame port face 6 and housed in the box-shaped frame 2, so that the adjacent darkening burners 3 can be placed between adjacent darkening burners 3. Is a light mixing chamber 15 provided with an elongated light flame port 14 for jetting a light air-fuel mixture having a high air mixing ratio.
Are formed.

Each enriching burner 3 has a lean gas passage 11 for supplying a mixture of fuel gas and combustion air to a lean mixing chamber 15, and a fuel gas and a combustion gas flowing through the lean gas passage 11. A light introduction port 12 for introducing air for use is provided, and a large number of ejection holes 13 are formed in the light gas passage 11 on both sides in the width direction of the flame port surface 6. And it is comprised so that combustion air can be supplied upward from the air chamber 5 through the air conditioning perforated plate 16 which forms the bottom wall of the box-shaped frame 2. In addition, as shown in FIG. 2, the width of the flame outlet face 6 is larger than that of the rich burner 3a in the light gas passage 11 of the rich burner 3a disposed at both ends in the width direction of the flame outlet face 6. The jet holes 13 are formed only in the inner side of the direction, and only the air from the air chamber 5 flows outside of the burner face 3a in the width direction of the burner face 3a.

The thickening inlet 10 provided in the thickening burner 3
And the lean inlet 12 are all arranged side by side in the same direction, and a gas header 17 for distributing and supplying the rich fuel gas and the lean fuel gas is provided on the front surface thereof, and is attached to the gas header 17. The thick gas nozzle 18 is connected to each of the thick inlets 10, and the light gas nozzle 19 is connected to each of the light inlets 12.
A part of the combustion air in the air chamber 5 is sucked at a predetermined ratio by an ejector action by blowing the fuel gas from each of the gas nozzles 18 and 19, and each of the inlets 1
It is configured to be introduced at 0,12. Further, the gas header 17 is provided with an opening / closing valve in a gas supply path (not shown) for supplying a fuel gas to the rich gas nozzle 18 and the lean gas nozzle 19 and an adjusting valve for adjusting the amount of supplied gas, respectively. Can be adjusted according to a desired heating amount.

As shown in FIG. 4, the enrichment burners 3 on the side of the enrichment burner 3 on the side of the enrichment burner 3 on the side of the enrichment burner 3 as shown in FIG. A plate-like cover body 20 covering the side surface is provided in contact with the side surface of the dark burner 3,
The cover body 20 is caulked and attached to the dark burner 3 at both ends in the longitudinal direction of the dark burner 3. Each cover body 20 has one outer side in the width direction of the flame port face 6.
The sheet metal rectifying plates 23 are attached, and each rectifying plate 23
Is configured so that the upper end thereof is substantially the same height as the flame outlet surface 6. When the plurality of dark burners 3 are stored in the box-shaped frame 2, the cover 20 and the box-shaped frame 2 adjacent to each other are placed.
The air-fuel mixture flows through the space formed by the air flow and is rectified by the rectifying plate 23, and then the air-fuel mixture is ejected from the light flame port 14.

In this way, the unevenness that obstructs the flow of the lean mixture is eliminated by the cover body 20 and the flow of the lean mixture is made smooth. Therefore, in order to reduce NOx, the air as the fuel gas as a whole is reduced. Even if the mixing ratio is increased and the flow rate of the lean air-fuel mixture is increased, the flow of the lean air-fuel mixture is stabilized, and stable combustion can be performed.

A bulging portion integrally formed with the cover member 20 is provided at a middle portion of each cover body 20 in the flowing direction of the lean gas mixture so as to protrude toward the flowing lean gas mixture. The cover body 20 has a shape corresponding to the rich burner 3 so as to act as a mixing promoting section 21 for promoting the mixing of the air-fuel mixture, and to allow the rich mixing section 9 to enter the space inside the mixing promoting section 21. It is configured. In other words, the lean air-fuel mixture is sufficiently mixed in the mixing promoting section 21, and the sufficiently air-blended light air-fuel mixture is ejected from the light flame outlet portion 14 so that the lean air-fuel mixture can be burned. Can be performed.

More specifically, the combustion process will be described. The fuel gas supplied through the gas supply passage is supplied to the enrichment gas nozzle 18,
A part of the combustion air in the air chamber 5 is sucked at a predetermined ratio through the light gas nozzle 19 by an ejector action, and is introduced into the concentration inlet 10 and the light inlet 12, respectively. The fuel gas supplied from the concentration inlet 10 and the air chamber 5
And the supplied combustion air is mixed in the rich mixing section 9,
A rich air-fuel mixture having a small air mixing ratio is supplied to a deep flame opening 7
Squirts more.

On the other hand, the fuel gas supplied from the lean inlet 12 and the combustion air supplied from the air chamber 5 are
The light mixing chamber 15 is ejected from a number of ejection holes 13 formed in the light gas passage 11 through the light gas passage 11.
And a light air-fuel mixture having a high air mixing ratio is ejected from the light flame port 14. As described above, the rich air-fuel mixture spouted from the rich flame opening 7 is burned, and the lean air-fuel mixture is burned by the rich flame generated in the rich flame opening 7.

[Other Embodiments] (1) In the above-described embodiment, the plate-like cover body 2 covers substantially the entire both sides in the width direction of the flame port surface 6 of the enrichment burner 3.
0 is provided, but the cover body 20 only needs to smooth the flow of the lean mixture as a whole, and a part of the both side surfaces in the width direction of the flame port surface 6 of the rich burner 3 is formed. It may be covered.

(2) In the above embodiment, the cover body 20 is provided in contact with both side surfaces of the rich burner 3, but the light mixture flows between the adjacent cover bodies 20. As long as there is some space between the cover body 20 and the dark burner 3, it may be sufficient.

(3) In the above-described embodiment, the mixing promoting portion 21 as a bulging portion integrally formed with the cover body 20 is provided at an intermediate portion of the cover body 20 in the flow direction of the lean mixture. Instead of providing the portion 21, the cover body 20 may be formed in a flat plate shape so as to make the flow of the lean mixture smooth.

(4) In the above embodiment, the cover 20
Are caulked and attached to the dark burner 3 at both ends in the longitudinal direction of the dark burner 3.
0 may be attached to the burner 3 on both sides in the width direction of the flame port surface 6 by other methods.

(5) In the above embodiment, one rectifying plate 2
3 is mounted outside the cover body 20 in the width direction of the flame outlet face 6, but the number of the current plate 23 is not limited to one, and two or more current plates 23 may be used. 2
You may comprise so that it may attach to the width direction outer side of the flame mouth surface 6 rather than 0.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a concentration combustion device.

FIG. 2 is a longitudinal sectional front view of the concentration combustion device.

FIG. 3 is a plan view of the concentration combustion device.

FIG. 4 is a perspective view of an enriching burner that constitutes the concentration combustion apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 2 Casing 2a holding part 3 Rich burner 6 Flame face 7 Rich flame port 9 Rich mixing part 20 Cover body 21 Mixing promotion part

Claims (5)

[Claims] 1. A fuel supply system comprising: a fuel gas and combustion air; and a rich mixing section for generating a rich air-fuel mixture. A plurality of rich burners, each having a rich flame port for ejecting and burning an air-fuel mixture on the flame port surface, are arranged side by side at intervals in the width direction of the flame port surface, and are disposed between the rich burners. Is configured such that a lean mixture of fuel gas and combustion air flows, and a lean mixture is ejected from an elongated lean flame portion provided between the flame surfaces of the rich burner to burn the mixture. A light and shade combustion apparatus, wherein plate-shaped cover bodies respectively covering both side surfaces of the rich burner in the width direction of the flame outlet face are provided while being held by the rich burner, and cover bodies adjacent to each other are provided. A light-and-dark combustion apparatus configured such that the lean air-fuel mixture flows between the two. 2. The light-to-dark combustion apparatus according to claim 1, wherein the cover body is provided so as to be in contact with a side surface of the rich burner. 3. The mixing body according to claim 1, further comprising a mixing promoting portion protruding toward the flowing lean air-fuel mixture and promoting the mixing of the lean air-fuel mixture, at an intermediate portion of the cover body in the flowing direction of the lean air-fuel mixture. The shade combustion device as described. 4. The light-to-dark combustion according to claim 3, wherein the mixing promoting portion is constituted by a bulging portion integrally formed with the cover body, and the rich mixing portion is inserted into a space inside the bulging portion. apparatus. 5. A prismatic casing for accommodating the enrichment burner, a plurality of holding portions for holding the enrichment burner, and a plurality of enrichment burners held by the plurality of holding portions. The light-and-dark combustion apparatus according to any one of claims 1 to 4, wherein the lean air-fuel mixture flows in a space formed by the cover body and the casing.