JPH10292906A - Combustion equipment - Google Patents

Abstract

(57) [Problem] To provide a combustion device in which generation of nitrogen oxides is suppressed by combustion of a plurality of air-fuel mixtures having different fuel gas concentrations. SOLUTION: This combustion device burns a fuel-rich first air-fuel mixture and a fuel-lean second air-fuel mixture adjacent to each other,
The first burner unit (1a, 4a) for burning the first air-fuel mixture
a), a second burner section (1) for burning the first air-fuel mixture;
b, 4b), and the total burner area of the second burner is
Flame holes (2
a, 5a, 14a, 2b, 5b, and 14b) are realized in different forms to achieve rich and lean combustion of fuel gas, thereby suppressing vibration and generation of nitrogen oxides.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus in which generation of nitrogen oxide is suppressed.

[0002]

2. Description of the Related Art It is said that nitrogen oxides (NOx) in combustion gas generated from burners in various combustion devices are harmful to the human body and are released into the atmosphere to cause acid rain and photochemical smog. ing. For this reason, measures have been taken to reduce the amount of NOx generated in the combustion device.

[0003]

The conventional countermeasures for suppressing the generation of NOx are for large-scale combustion devices for industrial use or the like, which have legal restrictions, and are small for home use or small business use. Combustion devices have a problem that the countermeasures cause noise and the like, and therefore, it cannot be said that sufficient countermeasures are taken.

[0004] In a large combustion device, the static pressure of the combustion fan can be increased, so that the flow of combustion gas and air can be easily controlled, the degree of freedom of the burner layout is high, and noise countermeasures are easy. In addition, the conditions for measures against noise are moderate, the combustion chamber can be large, and complete combustion is easy even if a measure for reducing NOx by so-called slow combustion is taken. However, a small-sized combustion device does not have these advantages, the static pressure of the combustion fan cannot be increased, it is difficult to control the flow of combustion gas and air, the layout of the burner is low, and noise measures are troublesome. Therefore, the conditions for countermeasures against noise are severe, and therefore, it is more difficult to reduce NOx with a small-sized combustion device than with a large-sized combustion device.

Accordingly, an object of the present invention is to provide a combustion apparatus in which the generation of nitrogen oxides is suppressed by the combustion of a plurality of air-fuel mixtures having different fuel gas concentrations.

[0006]

SUMMARY OF THE INVENTION A combustion apparatus according to the present invention is a combustion apparatus for burning a fuel-rich first air-fuel mixture and a fuel-lean second air-fuel mixture adjacent to each other. A first burner section (1a, 4a) for burning air; and a second burner section (1b, 4b) for burning a second air-fuel mixture. Are set larger than the burner hole area of the burner, and the burner holes (2a, 2b, 5a, 5a)
b, 14a, and 14b) are realized to achieve the concentration combustion of the fuel gas, thereby suppressing the generation of nitrogen oxides.

According to the present invention, a plurality of flame holes (2) are provided.
a, 5a, 14a).
a) and a plurality of burner holes (2b, 5b, 14b), and a second burner portion (1b, 4b) having a total burner hole area larger than the burner hole area of the first burner portion.
b), the second burner portion and the first burner portion are alternately arranged, and a first fuel-rich mixture is supplied to the first burner portion, and the second burner portion is supplied to the second burner portion. The fuel-lean second air-fuel mixture is supplied to the burner section, and the fuel gas amount of the second air-fuel mixture is set to be larger than that of the first air-fuel mixture.

With this configuration, a fuel-rich mixture is ejected from the flame holes of the first burner and burns, and a fuel-lean mixture is ejected from the flame holes of the second burner. , Each burning.

The combustion of the fuel-lean mixture on the second burner section side, that is, the mixture of excess air, alone lacks flame stability. However, a stable flame due to the fuel-rich mixture exists adjacent to this flame, and the flame due to the fuel-rich mixture on the first burner section acts as a seed flame, so that the second flame is used. The flame of excess air on the burner part side can be stabilized. Therefore, no flame lift or oscillating combustion occurs with complete combustion, and the generation of noise is suppressed.

[0010] Since the combustion of the fuel-lean mixture stabilized by the flame of the fuel-rich mixture is the combustion of excess air, the excess air performs a cooling action and the temperature of the flame is maintained at a low temperature. Thus, generation of NOx can be reduced. Moreover, the fuel gas amount in the fuel-lean mixture is larger than the fuel gas amount in the fuel-rich mixture,
The generation amount of NOx with respect to the combustion amount of the entire burner including the first and second burner portions is reduced.

According to a second aspect of the present invention, the first burner portion and the second burner portion each have a flame hole group which is arranged in a cascade in one direction and has a different flame hole area. The first and second burners are alternately arranged to alternately arrange the different groups of flame holes. With such an arrangement, the flame on the second burner section side can be stabilized by the flame on the first burner section side.

According to a third aspect of the present invention, the flame hole surface formed by the flame hole of the first burner portion and the flame hole surface formed by the flame hole of the second burner portion are set to the same plane. It is characterized by.
That is, since the flame on the first burner portion side is smaller than the flame on the second burner portion side, the flame on the first burner portion side and the second burner portion side are smaller.
By making the flame generation site on the burner side of the same plane,
The flame on the first burner section side functions as a pilot flame with respect to the flame on the second burner section side.

According to a fourth aspect of the present invention, the height of the flame hole formed by the flame holes of the first burner portion and the flame hole surface formed by the flame holes of the second burner portion are set to different heights. It is characterized by the following. That is, since the flame on the first burner section side is smaller than the flame on the second burner section side, the flame on the first burner section side does not protrude from the flame on the second burner section side. The part can be set to a place that becomes a pilot flame with respect to the second burner part side.

According to a fifth aspect of the present invention, a flame hole surface formed by the flame hole of the first burner portion is made to protrude from a flame hole surface formed by the flame hole of the second burner portion. I do. That is,
Since the flame on the first burner portion side is smaller than the flame on the second burner portion side, the flame hole surface formed by the flame holes of the first burner portion is the flame hole surface formed by the flame holes of the second burner portion. Even if it is made to protrude further, the flame on the first burner part side becomes the pilot flame with respect to the second burner part side.

According to a sixth aspect of the present invention, the first burner portion or the second burner portion is provided with rectifying means (ribbons 8, 10) at the opening portions of the respective flame holes. And By providing the rectifying means, the air-fuel mixture can be uniformly injected from each of the flame holes, so that the lift of the flame and the vibration combustion can be prevented.

According to a seventh aspect of the present invention, as shown in FIG. 6, the first burner section has large-diameter flame holes (14a) formed at regular intervals, and the second burner section has , The first
The flame holes (14b) are smaller than the flame holes of the first burner portion, and the installation interval is narrower and the number of the flame holes is larger than that of the first burner portion. Since the first burner portion is a pilot flame for the second burner portion, the first burner portion has large diameter flame holes formed at regular intervals to reduce the number of flame holes corresponding to the shape of the flame holes. The second burner portion has a smaller number of flame holes than the first burner portion, and has a narrower installation interval than the first burner portion to form a large number of flame holes.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

FIG. 1 shows a first embodiment of a combustion apparatus according to the present invention, and FIG. 2 shows a longitudinal sectional view thereof. In this combustion device, first burners 1a and second burners 1b are alternately arranged, and the burners 1a and 1b have upper and lower slit-shaped flame holes 2a and 2b arranged in a row. It is a vertical flat burner body, and a plurality of these burners are arranged alternately adjacently to constitute a single burner. Air-fuel mixtures having different mixing ratios of fuel gas and air are supplied to the burners 1a and 1b. And the burner sections 1a, 1b
Constitute first and second groups of flame holes A and B. Flame hole 2
b is set to be larger than the flame hole 2a, and the total flame area of each of the flame hole group A of the flame hole 2a and the flame hole group B of the flame hole 2b is greatly different. The total flame hole area is set to be larger than the total flame hole area of the flame hole group A. In this embodiment, the flame holes 2a and 2b have the same flame surface. The formation and supply of the air-fuel mixture to each of the burners 1a and 1b can be the same as in a conventional Bunsen burner or the like.

A fuel-rich mixture is supplied to the burner section 1a, and a fuel-lean mixture is supplied to the burner section 1b. For example, assuming that the theoretical air amount λ = 1, the air ratio of the air-fuel mixture supplied to each of the burners 1a and 1b is λ ≒ 0.4 for a fuel-rich air-fuel mixture and λ ≒ 1.2 for a fuel-lean air-fuel mixture. Set to ~ 1.5. Also, the burner section 1a,
The ratio of the amount of fuel gas supplied to the burner unit 1b is set, for example, to about 3: 7 fuel gas amount of the burner unit 1a: fuel gas amount of the burner unit 1b = 3: 7. To be larger than the amount of fuel gas to be supplied.

In such a configuration, a fuel-rich mixture is ejected from the flame holes 2a of the burner portion 1a and burns, and a fuel-lean mixture is ejected from the flame holes 2b of the burner portion 1b. Burn. Since the combustion in the burner section 1b is the combustion of excess air with a fuel-lean mixture, the combustion alone is unstable due to lift of the flame 3b and oscillating combustion. On the other hand, the combustion in the burner section 1a is a combustion by a fuel-rich mixture, so that the flame 3a
Is stable. Since the flames 3a and 3b are adjacent to each other, the stable flame 3a of the burner section 1a acts as a pilot flame, stabilizes the combustion of the burner section 1b, and lifts the flame 3b and generates vibration. Generation can be prevented. In this case, the form of generation of the flame 3a on the side of the burner 1a is smaller than that of the flame 3b on the side of the burner 1b in accordance with the flame hole 2a. Works effectively as a pilot.

Since the combustion in the burner section 1b is the combustion of excess air, the temperature of the flame 3b is kept low by the cooling action of the excess air, and the generation of NOx is reduced. Since the amount of fuel gas supplied for combustion as such a fuel-lean mixture is larger than the amount of fuel gas supplied for fuel-rich mixture, the generation of NOx with respect to the combustion amount of the entire burner The amount is also small.

Next, FIG. 3 shows a second embodiment of the combustion apparatus of the present invention, and FIG. 4 shows a combustion mode thereof. The combustion device according to this embodiment has a second burner section 4b for burning a fuel-lean mixture between first burner sections 4a for burning a fuel-rich mixture. In this combustion device, the burner portion 4a has a slit-like flame hole 5a on the upper side.
Is formed narrowly to form a space between the side wall 7 and the second burner 4b. A flame hole 5b is formed. As shown in FIG. 4, a sleeve flame hole 9 can be formed on the lateral side of the tip end ejection portion 6 of the burner portion 4a as required.

[0023]
. FIG. 5 shows a third embodiment of the combustion apparatus of the present invention and a combustion mode thereof. In the combustion device of this embodiment, instead of the slit-shaped flame hole 5a of the burner portion 4a shown in FIG. At the same time, a sleeve flame hole 9 and a side wall 7 for forming a sleeve flame are formed at intervals on the outside, and the height of the flame hole surface of each burner portion 4a, 4b is made different. In this embodiment, the flame hole surface on the burner portion 4a side is set higher than the flame hole surface on the burner portion 4b side.

In such a configuration, a plurality of units can be arranged side by side as an installation unit to form a burner having a desired combustion amount, and the burner portion 4b is sandwiched between the burner portions 4a on both sides. With the configuration maintained, a burner can be configured by alternately and continuously arranging a plurality of the burner portions 4a and 4b, as in the embodiment shown in FIGS. In addition, since the flame 12a on the burner portion 4a side is smaller than the flame 12b on the burner portion 4b side, the height is made different, that is, the flame generation point is set higher on the burner portion 4a side than on the burner portion 4b side. Thus, the flame 12a on the burner part 4a side functions as a pilot flame for the flame 12b on the burner side 4b side.

Therefore, in addition to the operation similar to the structure of FIGS. 1 and 2, the flame holes 5a, 5
b, the generation of noise can be further reduced by the rectifying action of the air-fuel mixture. In the case of forming the sleeve flame 11 in the burner portion 4a, the flame 12a itself of the burner portion 4a and the burner The flame 12b of the portion 4b can be further stabilized.

Next, FIG. 6 shows a fourth embodiment of the combustion apparatus of the present invention. That is, a large number of flame holes are formed by the ceramic plate 13 in the combustion apparatus of this embodiment. That is, on the ceramic plate 13, a large number of flame holes are linearly arranged to form first and second flame hole groups A and B. These flame hole groups A and B are alternately arranged in a row. Has been established. The diameter of the flame holes 14b of the flame hole group B is smaller than the diameter of the flame holes 14a of the flame hole group A, and the number of the flame holes is the same. In this case, the flame hole group B is composed of a large number of small diameter flame holes 14b arranged in two rows. Then, to the flame holes 14a and 14b of each of the flame hole groups A and B, a mixture of fuel gas and air having different mixture ratios is supplied by a mixture distribution mechanism (not shown).

In the above configuration, the flame holes 14 of the flame hole group A
When the fuel-rich mixture is supplied to a and the fuel-lean mixture is supplied to the flame holes 14b of the flame hole group B to perform the lean combustion, the combustion by the flame holes 14b of the flame hole group B is performed as described above. Excessive air combustion and a large number of small holes 14
Since the combustion is subdivided by b, the temperature of the flame 15b is maintained at a lower temperature, and the generation of NOx is further reduced. Further, similarly to the above-described embodiment, the flame 15b is stabilized by the flame 15a of the fuel-rich mixture by the flame holes 14a of the flame hole group A, so that the lift and the oscillating combustion hardly occur.

In the case where a large number of flame holes are formed by the ceramic plate 13 or the like as in the above embodiment, although not shown, the flame holes 14a and 14b of the flame hole groups A and B are vertically and horizontally adjacent. It is also possible to adopt a configuration arranged so as to perform

In the combustion apparatus of the above embodiment, the burners 1a, 1b, 4a, 4b or the flame holes of the flame hole groups A, B are provided with a fuel-rich mixture or a fuel-lean mixture. Although it is configured so that it is set and supplied in advance, it may be configured so that any one can be supplied and combustion can be performed as needed.

Next, FIG. 7 shows a comparison of the NOx generation amount between the combustion device of the present invention and the conventional combustion device. This comparison result shows that, in the combustion device as shown in FIG. 1, the mixture ratio of the fuel-rich mixture is set to λ = 0.4 to 0.7, and the overall air ratio is shown on the horizontal axis in the figure. It shows the amount of NOx generated when the air ratio of the fuel-lean mixture is adjusted to be a value and the fuel is burned. In addition, the ratio of the amount of combustion by the fuel-lean mixture to the amount of combustion by the fuel-rich mixture is:
7.5: 2.5. The indicated air ratio is a value including the cooling air when the cooling air flows outside the burner, and is (1.2), (1.3), or (1.4). ) Is a value indicating the air ratio not including the cooling air. It can be seen that in such a combustion device, the amount of generated NOx is significantly reduced as compared with a conventional general Bunsen burner.

FIG. 8 shows a flame lift limit in the combustion device of the present invention and the conventional combustion device. A
Is a lift limit in a case where a fuel-lean mixture is supplied to one of the first or second burner portion and the flame hole group and burned, that is, when flame holding by a flame of a fuel-rich mixture is not performed. This limit value is about λ = 0.7. B
Indicates a lift limit in a conventional general Bunsen burner having a flame holding mechanism, and this limit is λ = 1.3.
It is about. C is a case where a fuel-lean mixture is supplied to one of the first or second burner portion and the flame hole group and burned, and the other side is subjected to flame holding by a flame of the fuel-rich mixture. That is, it indicates the lift limit when the combustion device of the present invention is applied, and λ is about 3.0. As is apparent from such a comparison result, the combustion device of the present invention, compared to a conventional general Bunsen burner, burns the air-fuel mixture due to excess air in a stable state, and emits NOx.
Can be reduced.

[0032]

As described above, according to the present invention,
Since the combustion of a lean mixture and the combustion of a rich mixture are performed in parallel to perform a complex combustion, the combustion of excess air by a lean mixture that is poor in flame stability alone is reduced by the use of a rich fuel mixture. Since the flame can be held by the flame generated by the combustion of the air-fuel mixture, the combustion of the air-fuel mixture containing excess air can be stabilized, complete combustion can be realized, and the generation of NOx can be reduced by the combustion of the excess air. , Can suppress the generation of noise, without increasing the noise,
The amount of generated NOx can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a combustion device of the present invention.

FIG. 2 is a longitudinal sectional view of the combustion device shown in FIG.

FIG. 3 is a perspective view showing a second embodiment of the combustion device of the present invention.

FIG. 4 is a sectional view showing a combustion state in the combustion device shown in FIG. 3;

FIG. 5 is a sectional view showing a third embodiment of the combustion device of the present invention.

FIG. 6 is a perspective view showing a fourth embodiment of the combustion device of the present invention.

FIG. 7 shows the N of the combustion device of the present invention and a conventional Bunsen burner.
It is explanatory drawing which shows the comparison of Ox generation amount.

FIG. 8 is an explanatory diagram showing a lift limit of a flame generated in a burner portion or a flame hole group of the combustion device of the present invention.

[Explanation of symbols]

 A First burner hole group B Second burner hole group 1a, 4a First burner portion 1b, 4b Second burner portion 2a, 2b, 5a, 5b, 14a, 14b Flame hole 3a, 3b, 12a, 12b , 15a, 15b Flame 8, 10 Ribbon (rectifying means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kimio Mochizuki 201 Nishi-Kashiwara Nitta, Fuji City, Shizuoka Prefecture Inside Takagi Industries Co., Ltd. (72) Inventor Shigetoshi Akiyama 201 Nishi-Kashiwara Nitta, Fuji City, Shizuoka Prefecture Takagi Inside the corporation

Claims (7)

[Claims] A first burner portion having a plurality of flame holes; and a second burner portion having a plurality of flame holes and having a total flame hole area larger than a total flame hole area of the first burner portion. A second burner section and the first burner section are alternately arranged, and a first fuel-rich mixture is supplied to the first burner section; A combustion apparatus characterized in that a second fuel-lean mixture is supplied to a burner section, and a fuel gas amount of the second gas mixture is set to be larger than that of the first gas mixture. 2. The first and second burners, wherein each of the first and second burners has a series of flame holes having a different flame hole area in a tandem state in one direction. 2. The combustion apparatus according to claim 1, wherein the different flame holes are alternately arranged by alternately arranging the portions. 3. A flame hole surface formed by a flame hole of the first burner portion and a flame hole surface formed by a flame hole of the second burner portion are set to the same plane. A combustion device as described. 4. A flame hole surface formed by a flame hole of said first burner portion and a flame hole surface formed by a flame hole of said second burner portion are set at different heights. 2. The combustion device according to 1. 5. The combustion according to claim 1, wherein a flame hole surface formed by a flame hole of said first burner portion is made to protrude from a flame hole surface formed by a flame hole of said second burner portion. apparatus. 6. The combustion apparatus according to claim 1, wherein the first burner section or the second burner section includes a flow straightening means at an opening of each flame hole. 7. The first burner portion has large-diameter flame holes formed at regular intervals, and the second burner portion has a flame hole smaller than the first burner portion. 2. The combustion apparatus according to claim 1, wherein an installation interval is narrower than the flame holes of the first burner and the number of installations is set larger.