JPH08121713A - Combustion device - Google Patents

Abstract

PURPOSE: To lower the noise and NOx in the emission and simultaneously prevent red heat at the flame hole by increasing the ratio of primary air. CONSTITUTION: A combustion part 15 provided in a combustion chamber 12 is composed of a series of thin-gas burners 13 and a series of thick-gas burners 14 provided side by side alternately. For a set of thin-gas throat 19 and thick-gas throat 20, a thin-gas nozzle 21 and a thick-gas nozzle 22 are provided in opposition to the thin opposition to the thin-gas throat 19 and the thick-gas throat 20 respectively. The flame-hole part of the thick-gas burner is formed of a number of plates laid in a laminate with the surface of the flame hole cleared of projections and made plane. By forming over the burners a flame of thick gas with primary air at an increased ratio and a flame of thin gas alternately the flame is improved in stability and, while NOx in the emission and the noise of the combustion can be reduced, the possibility of red heat at the flame hole of the thick-gas burner and backfire to the thick-gas nozzle can be lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention provides low NO due to rich and lean combustion.
The present invention relates to a burner combustion device designed for x conversion.

[0002]

2. Description of the Related Art A conventional combustion apparatus of this type is shown in FIGS.
As shown in (1) and (2), the combustion chamber 4 is provided with the combustion section 3 configured by alternately arranging the lean burner 1 and the rich burner 2 side by side. An air chamber 5 is provided on the upstream side of the combustion section 3, and a fan 6 is provided at the center of the outer wall of the air chamber 5. A lean nozzle 9 and a rich nozzle 10 are arranged in the air chamber 5 so as to face the lean throat 7 and the rich throat 8 which are sequentially faced from the upstream side. Further, a resistance plate 11 is provided between the lean throat 7 and the rich throat 8 facing the air chamber 5, and between the lean nozzle 9 and the rich nozzle 10.

In the combustion apparatus having the above structure, the air supplied from the fan 6 to the air chamber 5 is distributed to the rich throat 8 via the lean throat 7 and the resistance plate 11. The primary air supplied to the dense throat 8 by the resistance plate 11 is 2
It is limited to about 0 to 50% and mixed with the fuel ejected from the rich nozzle 10 to the rich throat 8 to form a rich air-fuel mixture, which is ejected from the rich burner 2 and ignited to form a rich flame having a low oxygen concentration. On the other hand, the fuel injected from the lean nozzle 9 to the lean throat 7 mixes with the preceding air to form a lean air-fuel mixture, which is ejected from the lean burner 1 and burns due to the thermal effect of the rich flame, resulting in a lean flame having a high oxygen concentration. Is formed. As described above, in the rich-lean combustion, the NOx concentration can be reduced as a whole because the lean flame having a low NOx concentration exists.

[0004]

However, in the configuration of the conventional combustion apparatus described above, in order to further reduce NOx, it is necessary to reduce the ratio of the combustion amount of the rich burner to the total combustion amount and increase the lean flame amount. However, there is a problem that combustion noise is increased by increasing the ratio of the unstable lean flame and the combustibility is poor.

The present invention solves the above problems by improving the combustibility and reducing the noise, and further reducing the thermal influence of the flame on the burner mouth of a rich burner and the burner of a lean burner to reduce the burner. The purpose is to improve the durability of.

[0006]

In order to achieve the above object, the first means for solving the problems of the present invention is a combustion section constituted by alternately arranging a lean burner and a rich burner, and a rich burner for the total burned amount. Combustion amount control means for making the ratio of the combustion amount of the flame 30 to 40%, and the primary air ratio of the rich flame 70 to 100%
And a primary burner primary air amount control means for making a thick burner flame mouth part made up of laminated plates, and this flame mouth part is a flat surface without protrusions on the flame mouth surface. is there.

A second means for solving the problem is to construct a lean burner flame port portion by laminating plates in a laminated form, and the flame port portion is made flat without a protrusion on the flame port surface.

[0008]

The present invention has a primary air ratio of 70 due to the above construction.
To 90% very stable rich flame and lean flame are alternately formed on the burner, the lean flame is also stable and compared to the conventional combustion device that produces rich flame with primary air ratio of 20 to 50%. , The combustion property of the lean flame is improved, and the combustion noise is reduced. Also, by increasing the primary air ratio of the rich flame, the primary air ratio of the lean flame decreases, and the oxygen concentration of the lean air-fuel mixture supplied to the rich flame decreases, so the flame temperature of the rich flame drops, so NOx generated from the flame is also reduced. Therefore, NOx generated from the rich flame / lean flame as a whole is reduced as compared with the conventional case where the primary air ratio of the rich flame is set to 20 to 50%. In addition, the burner section of the rich burner is laminated in a stack, and the projecting section of this burner section is made flat by eliminating the projections on the surface of the burner, so that the influence of the heat received from the flame formed on the rich burner is affected. To reduce the red heat of the flame mouth.

Next, the burner portion of the lean burner is also laminated so that the burner portion has a flat surface without the protrusions on the burner surface, so that the heat from the flame formed on the lean burner is reduced. It reduces the effect of receiving heat and reduces red heat at the flame mouth.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, reference numeral 12 denotes a combustion chamber, in which a lean burner 13 and a rich burner 14 are alternately arranged, and the left and right ends of the burner portion 15 are the rich burners 14.
Is provided. The rich burner 14 is arranged so as to be in contact with the narrowed portion of the lean burner 13. A fan 18 is provided at the center of the outer wall of the air chamber 17 separated from the combustion section 15 by a partition wall 16. Reference numerals 19 and 20 denote a lean throat and a rich throat, which are sequentially exposed from the upstream side of the air chamber 17. Reference numerals 21 and 22 denote lean nozzles and rich nozzles, respectively, which are provided with combustion amount control means 23 (not shown) for controlling the ratio of the combustion amount of the rich burner to the total combustion amount (hereinafter referred to as the density ratio) to 30 to 40%. ing. Lean nozzle 21, thick nozzle 22
Are arranged so as to face the lean throat 19 and the rich throat 20. Lean throat 1 facing the air chamber 17
9, thick throat 20, lean nozzle 21 and rich nozzle 22
A primary burner primary air amount control means 24 for adjusting the primary air ratio of the rich flame to 70 to 90% is provided between the and. FIG.
The details of the burner portion of the rich burner 14 are shown in FIG. The rich burner flame opening portion 25 is composed of a flame holding plate 26 and a main flame opening plate 27 forming a main flame opening. The flame holding plate 26 and the main flame opening plate 27 are laminated on each other in a laminated form, and the flame holding plate 26 is formed. Upper surface 28 of the main flame vent plate 27
9 have the same height, and the rich burner flame opening portion 25 is formed in a planar shape.

Next, the combustion operation in the above structure will be described. The air supplied from the fan 18 to the air chamber 17 is distributed to the lean throat 19 and the rich throat 20 via the rich burner primary air amount control means 24. Further, the fuel ejected from the rich nozzle 22 to the rich throat 20 is mixed with the preceding air, and the primary air ratio control means 24 for the rich burner controls the primary air ratio of the rich flame from 70 to 90% to form a rich air-fuel mixture. , And is ignited by a spark plug (not shown), and a rich flame is formed on the rich burner flame opening 25. On the other hand, the fuel injected from the lean nozzle 21 to the lean throat 19 mixes with the preceding air to form a lean air-fuel mixture having a primary air ratio of 160% to 200%, and is ejected from the lean burner 13 due to the thermal effect of the rich flame. It burns and a lean flame is formed. Therefore, the primary air ratio of rich flame / lean flame is as follows compared to the conventional rich-lean combustion.

[0013]

[Table 1]

Therefore, the present invention has a primary air ratio of 70 to 90.
%, A very stable rich flame and a lean flame are alternately formed on the burner, so that the lean flame is stable and the primary air ratio is 20
As compared with the conventional combustion device in which a rich flame of 50% to 50% is formed, the combustion property of the lean flame is improved and the combustion noise is reduced. Also, by increasing the primary air ratio of the rich flame, the primary air ratio of the lean flame decreases, and the oxygen concentration of the lean air-fuel mixture supplied to the rich flame decreases, so the flame temperature of the rich flame drops, so NOx generated from the flame is also reduced, and as a result, NO generated from the rich flame / lean flame as a whole.
x also has the effect of being able to be reduced as compared with the case where the primary air ratio of the conventional rich flame is set to 20 to 50%.

The primary air ratio of the rich flame is 70 to 90.
%, Which is higher than in the past, so the thick burner flame tip 25
The flame formed on the upper part is shortened, and the rich burner 25
And the heat received by the rich burner flame opening 25 from the flame increases, and the possibility that the rich burner flame opening 25 becomes red hot increases. However, according to the present invention, as described in FIG. 3, the thick burner flame opening portion 25 is formed by stacking the flame holding plate 26 and the main flame opening plate 27, which constitute the rich burner flame opening portion 25, in a laminated form and making them planar. Since there is no part that forms a flame port downstream of the flame base of the flame formed on the rich burner flame port 25, the heat received by the flame is much higher than when there is a protrusion on the flame port surface. Very few. Therefore, the heat received by the rich burner flame tip 25 is small,
There is an effect of reducing the red heat of the rich burner flame opening 25 and the flashback to the rich nozzle 22 that occurs when the red heat is maintained for a long time.

Next, the flame mouth portion of the lean burner 13 will be described. FIG. 4 shows the details of the flame mouth portion of the lean burner 13.
The lean burner flame opening 30 is composed of a burner outer wall plate 31 and a slit 32. The burner outer wall plate 31 and the slit 32 are laminated in a laminated manner, and the upper surface 33 of the burner outer wall plate 31 and the upper surface 34 of the slit 32 have the same height. The lean burner flame opening portion 30 is formed in a flat shape. The flame of the adjoining rich burner 14 is shortened by increasing the primary air ratio from 70 to 90%, and since the flame is close to the lean burner burner portion 30, the heat received by the lean burner burner portion 30 is reduced. Will increase. Also, when the combustion device fluctuates toward the air-deficient side due to disturbance such as strong wind, the primary air ratio of the lean flame decreases and the theoretical air ratio becomes 100%.
If the lean flame becomes short, the lean flame shortens, approaches the lean burner flame opening 30, and the lean burner flame opening 30 receives heat from the lean flame, which increases the possibility of red heat. However, in the present invention, since the burner outer wall plate 31 and the slit 32, which constitute the lean burner burner portion 30, are laminated and laminated in a flat form as described in FIG. Since there is no component that forms a flame mouth on the downstream side of the flame base portion of the flame formed on the burner flame mouth portion 30, the heat received by the flame is much less than when there is a protrusion or the like on the flame mouth surface. Therefore, the heat received by the lean burner flame opening 30 is small, and there is an effect that red heat of the lean burner air opening 30 and flashback to the lean nozzle 21 that occurs when the red heat is maintained for a long time can be reduced.

[0017]

As described above, according to the combustion apparatus of the present invention, the following effects can be obtained.

(1) The primary air ratio of rich flame is 70 to 90
%, The flame stability is improved to improve combustibility, NOx and combustion noise are reduced, and the burner burner section has a laminated cross section and a flat burner surface. As a result, it is possible to reduce red hot heat at the burner of the rich burner and flashback to the rich nozzle.

(2) The burner portion of the lean burner is laminated in cross-section and the burner surface is flat, so that the lean burner occurs in normal times when the combustion device fluctuates to the air-deficient side due to disturbance such as strong wind. It can reduce the red heat of the burner flame and the flashback to the lean nozzle.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a combustion apparatus according to an embodiment of the present invention.

FIG. 2 is a front partial cross-sectional view of the device.

FIG. 3 is a perspective view of a main portion of a rich burner of the device.

FIG. 4 is a perspective view of a main portion of a lean burner of a combustion apparatus according to another embodiment of the present invention.

FIG. 5 is a side sectional view showing a conventional combustion device.

FIG. 6 is a front partial cross-sectional view of the same device.

[Explanation of symbols]

 13 Lean Burner 14 Thick Burner 15 Combustion Section 21 Lean Nozzle (Combustion Amount Control Means) 22 Thick Nozzle (Combustion Amount Control Means) 24 Thick Burner Primary Air Amount Control Means 25 Thick Burner Flame Tip 30 Lean Burner Flame Tip

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Kanazaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] Claims: 1. A combustion section constituted by alternately arranging a lean burner producing a lean flame and a rich burner producing a rich flame, and the ratio of the burned amount of the rich flame to the total burned amount is 30 to 40%.
And a burner primary air amount control means for adjusting the primary air ratio of the rich flame to 70 to 90%, and the rich burner flame mouth portion has a configuration in which plates are stacked in layers. This flame port is a combustion device with a flat surface without the protrusions on the flame port surface. 2. A combustion section constituted by alternately arranging a lean burner for producing a lean flame and a rich burner for producing a rich flame, and a ratio of the burning amount of the rich flame to the total burning amount is 30 to 40%.
And a means for controlling the primary air amount for the rich burner that makes the primary air ratio of the rich flame 70 to 100%, and the lean burner flame mouth portion has a structure in which plates are stacked in a laminated manner.
Moreover, this flame mouth part is a combustion device in which the protrusions on the flame mouth surface are eliminated and made flat.