JP3103689B2 - Combustion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called rich / lean combustion, in which an excess fuel mixture (rich mixture) and an excess air mixture (light mixture) are simultaneously burned to suppress the generation of nitrogen oxides (NOX). Related to the device.

[0002]

2. Description of the Related Art Conventionally, a gray-scale combustion apparatus has been known as one of combustion apparatuses for achieving low NOx. This device simultaneously emits a rich air-fuel mixture with a low air ratio from some of the flame outlets and a light air-fuel mixture with a high air ratio from the other flames, and burns the mixture with the air-fuel mixture. It is.

[0003] For example, as shown in FIG.
H, a rich mixture (generally air ratio λ <1) is ejected, and a light mixture (generally air ratio λ> 1) is ejected from the adjacent light side flame port LH to burn simultaneously. In this case, the base of the flame from the deep flame RH (hereinafter, referred to as rich flame) becomes oxygen deficient, and the upper portion becomes oxygen deficient due to the exhaust gas from the flame from the light flame LH (hereinafter, referred to as lean flame). , NOX is suppressed. On the other hand, in the light flame from the light side flame port LH, since the fuel gas is lean, the flame temperature is lowered and the generation of NOX is suppressed, and the low NOX as a whole is achieved by a synergistic effect of these.

[0004]

However, although the rich air-fuel mixture burns well, the lean air-fuel mixture ejected from the light-side flame port has a high air ratio, so the combustion speed is low, and the lean flame tends to lift easily. Had a problem. For this reason, it was difficult to widen the combustion capacity range (turndown). An object of the present invention is to solve the above problems and improve the stability of combustion.

[0005]

A combustion apparatus according to the present invention for solving the above-mentioned problems is provided with a plurality of rich-side flame ports through which a rich mixture of fuel gas and combustion air is guided, and a fuel tank adjacent to the rich-side flame ports. Provided with a plurality of light-side flame ports through which a light air-fuel mixture having a higher air ratio than the rich air-fuel mixture is guided, and ejecting the respective air-fuel mixtures from the rich-side flame ports and the light-side flame ports. In the combustion device that burns, the light-side flame port is used for discharging a light air-fuel mixture.
One opening, and around or around the first opening downstream of the first opening.
Is an opening wider than the first opening due to walls erected on both sides.
And a wall forming the second opening.
A deceleration flame port that holds the base of the flame at the inside tip of the body
That is the gist.

[0006]

According to the combustion apparatus of the present invention having the above-described structure, the rich air-fuel mixture is ejected from the rich-side flame and the light-air mixture is ejected from the light-side flame to burn, and the light-side flame is a deceleration flame. As a result, the ejection speed of the light air-fuel mixture ejected from the light-side flame outlet decreases. Decrease
The rapid flame outlet has a second side wider than the first opening downstream of the first opening.
Has an opening, and squirts from the first opening as shown in FIG.
The lean mixture is expanded (φ1
→ .phi.2), with cause diffusion and vortex in the flame port passage of the air-fuel mixture, to reduce the air-fuel mixture blowing speed (inflow velocity V1> the ejection speed V2), at the inner end of the wall body forming the second opening flame
Keep the base of the flame. As a result, the flame holding properties of the light flame are improved, and the combustion is stabilized.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of the combustion apparatus of the present invention will be described below.

FIG. 2 shows a light-and-dark combustion apparatus of a type in which a flame port is formed in an aluminum plate as one embodiment.
A light mixture chamber 10 to which a light mixture is supplied and a rich mixture chamber 20 to which a rich mixture is supplied are provided so as to be divided into upper and lower sections, and a top plate of the light mixture chamber 10 is provided with a flame port forming plate 11. It has become. The flame port forming plate 11 is provided with a plurality of light-side flame ports 12 from which a light mixture is ejected and a plurality of deep-side flame ports 22 from which a rich mixture is ejected. Rich mixture chamber 20
The top plate 21 is provided with a plurality of cylindrical tubes 23 communicating with the rich mixture chamber 20 facing upward, and their ends are respectively surrounded so as to surround the periphery of the rich side flame port 22 on the back surface of the flame port forming plate 11. It is positioned. Therefore, the rich mixture chamber 20
Is supplied from the rich-side flame opening 22. The light-side flame port 12 is a deceleration flame port composed of a first opening 12A communicating with the light-side mixture chamber 10 and a second opening 12B above (downstream side) having a diameter larger than the first opening 12A. It is.

In this combustion device, the rich mixture and the light mixture supplied to the rich mixture chamber 20 and the lean mixture chamber 10 are ejected from the rich side flame port 22 and the light side flame port 12, respectively, and burn simultaneously. I do. In other words, the above-described dense combustion is performed. In this case, the light air-fuel mixture ejected from the light-side flame opening 12 is
The ejection speed is lower than that on the dark side. That is, as shown in FIG. 3, the light mixture which has passed through the first opening 12A and reached the second opening 12B is diffused and forms a vortex, as shown in FIG. Air blowing speed decreases. That is, the passing speed V1 at the first opening 12A
In contrast, the passing speed V2 at the second opening 12B decreases. As a result, the combustion speed and the ejection speed of the lean air-fuel mixture are balanced , and the inside of the wall forming the second opening 12B is formed.
The base of the flame is held at the side tip, so that the flame holding property of the light flame is improved and the combustion is stabilized. In addition, the light side flame port 1 that becomes the deceleration flame port
2, the second opening 12B may be formed in a tapered shape as shown in FIG.

The diameter of the light-side flame port 12 (the second opening diameter 1)
2B), the vibration combustion may be suppressed by using a plurality of types, as shown in FIG. That is, by varying the ejection speed of the light-side flame outlet, the combustion oscillation frequency is dispersed, and vibration at a specific frequency is suppressed.

Next, another embodiment will be described. FIG.
Represents a schematic configuration of a concentration combustion device using a press burner, and includes a rich burner unit 30 to which a rich mixture is introduced.
And a plurality of light-side burner units 40 to which a light air-fuel mixture is guided are alternately arranged in parallel.
2. The light-side flame ports 42 are provided in a row, and are configured so that the air-fuel mixture is ejected upward. The flame forming surface 41 of the light-side burner unit 40 is assembled so as to be positioned slightly lower (upstream) than the flame forming surface 31 of the dark-side burner unit 30.

In this combustion apparatus, the rich-side burner unit 3
The rich air-fuel mixture and the light air-fuel mixture are supplied to the 0 and light burner units 40, respectively, and burn simultaneously. In other words, the above-described dense combustion is performed. In this case, the light air-fuel mixture ejected from the light-side burner port 42 is diffused between the dark-side burner units 30 and generates a vortex, and flows upward between the dark-side burner units 30 at a speed lower than the passing speed of the light-side burner port 42. Pass through,
As shown in FIG. 7, the fuel burns from the level of the flame forming surface 31 of the dark side burner units 30 on both sides. That is, the light side flame 4
2 (corresponding to the first opening) and the dark side burner unit 3
A deceleration flame port is formed in a region between the 0 wall surfaces (corresponding to the second opening) . As a result, the flame holding properties of the light flame are improved, and the combustion is stabilized. As shown in FIG. 8, the light-side burner unit 40 may have a structure in which both sides of the light-side flame port forming surface 41 are formed in a tapered shape, and the light-side flame port 42 is provided at the center thereof.

In these embodiments, the following two are assumed as the air ratio of each air-fuel mixture, and any of them can be applied. The first case is when the air ratio of the rich air-fuel mixture ejected from the rich side flame outlet is less than 1.0 and the air ratio of the light-air mixture injected from the light side flame opening is 1.0 or more. Desirably, the air ratio of the rich mixture is about 0.8 or less, and the air ratio of the light mixture is about 1.3 or more. In the second case, the air ratio of the rich mixture is set to 1.0 or more, and the air ratio of the light mixture is set to be larger than that. In this case, the air ratio of the rich mixture is set to 1.2 to 1.4.
It may be higher.

Further, a configuration may be adopted in which secondary air for combustion is mixed. For example, as shown in FIG. 9, the secondary air supply path 50 is connected to the dark side burner unit 3 while the dark side burner units 30 and the light side burner units 40 are alternately arranged.
It may be provided between 0. In this case, since the air ratio of the lean mixture can be set lower, the lean flame is further stabilized.

The embodiments of the present invention have been described above.
The present invention is not limited to these embodiments at all, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention.

[0016]

As described above in detail, according to the combustion apparatus of the present invention, since the light-side flame port is a deceleration flame port, the flame holding property of the light flame is improved, the combustion is stabilized, and the turndown is reduced. It has an excellent effect that it can be large.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a deceleration flame port.

FIG. 2 is a schematic perspective view, partially broken away, of a combustion apparatus as an embodiment.

FIG. 3 is a schematic sectional view of a flame forming plate.

FIG. 4 is a schematic sectional view of another flame port forming plate.

FIG. 5 is a schematic sectional view of another flame port forming plate.

FIG. 6 is a partially cutaway schematic perspective view of a combustion device as another embodiment.

FIG. 7 is a partial sectional view of the combustion device.

FIG. 8 is a partial sectional view of a combustion device as a modification of the light-side burner unit.

FIG. 9 is an explanatory diagram showing a configuration for mixing secondary air for combustion.

FIG. 10 is a schematic explanatory view of a conventional combustion device.

[Explanation of symbols]

10: Light mixture chamber, 11: Flame forming plate, 12
... Light-side flame outlet, 12A ... first opening, 12B ... second opening, 20 ... rich mixture chamber, 22 ... rich-side flame outlet, 30 ... rich-side burner unit, 32 ... rich-side flame outlet, 40 ... Light side burner unit, 42 ... Light side flame outlet.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F23D 14/02-14/18 F23D 14/74 F23C 11/00 329-330

Claims (1)

(57) [Claims] 1. A plurality of rich-side flame openings through which a rich mixture of fuel gas and combustion air is introduced, and a light mixture provided adjacent to the rich-side flame openings and having a higher air ratio than the rich mixture. A plurality of light-side flame ports through which air is guided, and a combustion apparatus that blasts and burns each air-fuel mixture from the rich-side flame port and the light-side flame port, wherein the light-side flame port is a light air-fuel mixture. A first opening through which
Standing around the first opening or both sides downstream of the first opening
The second opening forming an opening wider than the first opening by the wall body
And an opening at the inner end of the wall forming the second opening.
A combustion device characterized in that it is a deceleration flame port for holding the base of the flame .