JP3104759B2 - How to burn fuel gas - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel gas combustion method suitable for a small-sized combustion device for home use, small business use, and the like.
You.

[0002]

2. Description of the Related Art Nitrogen oxides (NO _x ) in the combustion gas of burners of various combustion devices are toxic in themselves and are considered to be one of the causes of acid rain and photochemical smog. Therefore, the burner used in a combustion device, various measures to reduce the generation amount of the NO _X are taken.

[0003]

However, the conventional countermeasure is for a large combustion device for industrial use or the like, which is legally regulated, and is small for a small combustion device for home use or small business use. Therefore, the measures are not always sufficient.

In general, in a large combustion apparatus, thick and thin fuel combustion method is known as a method for reducing the NO _X. In this method, fuel burners are arranged on both sides of a burner rich in fuel and burnt.

In this rich / lean combustion method, when burning a fuel-lean mixture, the combustion temperature is reduced by excess air, and the NO.
_X generation is reduced. In addition, even when a fuel-rich mixture is burned, the generation of NO _X is also small due to an effect such as an insufficient amount of oxygen. The flame of the fuel-rich mixture is formed as a diffusion flame, and oxygen is supplied from excess air of the flame of the fuel-lean mixture to complete combustion. Also,
In a large-sized combustion device, turbulent combustion is possible, and the residence time of high temperature during combustion is shortened.
Contribute to O _X reduction. Thus, combustion of the air-fuel mixture in a combustion fuel rich mixtures of fuel lean is the overall combustion occurrence of the NO _X is low because it is less occurrence of the NO _X respectively obtained.

[0006] However, if these technologies were trying to use to the combustion device for home and small business, generation of noise, can not complete combustion from the combustion chamber very small, low-NO _X combustion with light and shade Significantly low NO even when applied
_X cannot be realized.

Accordingly, an object of the present invention is to provide a fuel gas combustion method in which generation of nitrogen oxides is suppressed by concentration combustion.

[0008]

According to a first aspect of the present invention, there is provided a fuel gas combustion method comprising: a fuel rich fuel gas;
This is a fuel gas combustion method that uses thin fuel gas combustion.
Thus, the first burners (1a, 4a) are arranged at regular intervals.
And the second burner section within the space between these first burner sections.
By arranging the burners (1b, 4b) of
The first and second burners are alternately arranged, and
Placing the first burner portion on a side to form a burner;
The first burner has a large number of circular or square flame holes.
(2a) is formed regularly to form a first flame hole group (A),
The second burner portion is larger than the flame holes of the first flame hole group.
Regularly forming circular or square flame holes (2b)
A second group of flame holes (B), and this second group of flame holes is
The hole area is set larger than the first flame hole group, and the first
The second group of flame holes is separated from the second group of flame holes and has a fuel-rich structure.
1 fuel gas is supplied to the second flame hole group,
A fuel with a larger amount of fuel and a higher air ratio than the fuel gas of No. 1
The lean second fuel gas is separated from the first group of flame holes.
Supplied, the first burner section and the second burner section
Supply cooling air from outside to the first burner section.
And the total amount of fuel gas supplied to the second burner section.
The total amount of air is increased and the fuel of the first fuel gas rich in fuel is increased.
Of the second fuel gas which is fuel-lean due to flame holding by burning
Combustion is stabilized .

[0009]

[0010] The combustion process of the fuel gas of the present invention according to claim 2, the formation lower subsidiary said first flame port group and the second flame port groups <br/> single ceramic plate It is characterized by.

[0011]

The fuel-rich mixture is ejected from the flame holes 2a constituting the first flame hole group A and burns, and the fuel-rich mixture is discharged from the flame holes 2b constituting the second flame hole group B. Erupts and burns.

In the combustion with the fuel-lean mixture, since the air is excessively contained, the flame temperature becomes low, and NO _x
It is possible to significantly reduce the generation amount of the gas (compared to the ordinary Bunsen burner) (30 ppm or less).

Although the combustion of the excess air alone has poor flame stability, the stable flame due to the above-mentioned fuel-rich mixture exists adjacent to these flames. Although the flame is to stabilize the flame of the excess air to the action of a pilot flame, the fuel rich mixture while the fuel lean mixture is capable of significantly low NO _X combustion at an internal fire side Since the flame temperature is high, N
O _X generation amount is very large as compared to the lean combustion.

Therefore, by increasing the amount of fuel gas to be burned in the group of flame holes supplying the fuel-lean mixture, to the amount of fuel gas to be burned in the group of flame holes supplying the rich mixture of fuel, NO _X generated from the flame port groups according to feed rate was found to decrease.

That is, since the amount of air in the flame of a fuel-lean mixture increases with the amount of gas, the amount of NO _X generated is reduced by the flame cooling effect.

Further, the amount of combustion of the flame of the fuel-rich mixture decreases due to the decrease in the gas amount, so that the total amount of NO _X generated by the flame of the fuel-rich mixture decreases.

The gas amount supplied to the fuel-lean mixture and the gas amount supplied to the fuel-rich mixture are, for example, 1.5: 1.
5: it is necessary to be about 1, NO _X concentration of the entire burner at this time it is possible to 60ppm or less, in one example, 2: 1 to 4: about 1.

[0018] The ratio of gas volume, for example, 1.5: If less than 1, greater than 60ppm amount of generated NO _X, also, for example, 5: 1 excess of the fuel lean mixture flame supplies The amount of air-fuel mixture supplied to the hole group is increased, so that noise is increased and thermal efficiency is reduced, which is not practical. Further, the ventilation pressure loss increases, causing problems such as an increase in the load on the fan motor and an increase in fan noise. Combustion of excess air by a fuel-lean mixture alone has poor flame stability, but the stable flame of the fuel-rich mixture described above acts as a pilot flame next to these flames. Stabilizes excess air flame. Therefore, the occurrence of noise is suppressed without causing a flame lift or vibration combustion.

[0019]

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

FIGS. 1 and 2 show one embodiment of the fuel gas combustion method of the present invention. Reference numerals 1a and 1b denote vertical flat first and second burners each having slit-shaped flame holes 2a and 2b arranged on the upper side, and a plurality of these burners are arranged adjacently and alternately to constitute a burner. , These burner parts 1
A mixture of fuel gas and air having different mixing ratios is supplied to a and b. That is, the first and second flame hole groups A and B are formed in the burner portions 1a and 1b, respectively. As a method of supplying the air-fuel mixture to each of the burner sections 1a and 1b, a method of mixing, and the like, an appropriate method in a conventional Bunsen burner or the like can be applied.

In the above configuration, a first fuel gas composed of a fuel-rich mixture is supplied to the burner section 1a, and a second fuel gas composed of a fuel-lean mixture is independently supplied to the burner section 1b. And burn each. For example, if the air ratio of the air-fuel mixture supplied to the respective burners 1a and 1b is stoichiometric air amount λ = 1, λ ≒ 0.4 for the fuel-rich air-fuel mixture as the first fuel gas, and In a fuel-lean mixture, which is a fuel gas, λ ≒ 1.2 to 1.5 is satisfied. The ratio of the amount of fuel supplied to the burner units 1a and 1b is, for example, about 3: 7: burner unit 1a: burner unit 1b.
To be larger than the amount of fuel gas to be supplied.

In the above 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 and burns from the flame holes 2b of the burner portion 1b.

Since the combustion in the burner section 1b is the combustion of excess air by a fuel-lean mixture, there is a risk that the combustion or combustion of the flame 3b alone may cause instability. On the other hand, the flame 3a is stable because the combustion in the burner section 1a is a combustion with a fuel-rich mixture. However, these flames 3a, 3b
Are present adjacent to each other, the stable flame 3a of the burner 1a acts as a pilot flame, stabilizes the combustion of the burner 1b, and prevents lift of the flame 3b and occurrence of oscillating combustion.

Since the combustion in the burner section 1b is the combustion of excess air in which the amount of air increases in proportion to the increase in the amount of gas, the temperature of the flame 3b is maintained at a low temperature by the cooling action of the excess air, and NO _x Of the burner portion 1a
In the combustion at, the amount of combustion decreases due to the decrease in the amount of gas,
Since the total amount of generation of O _X decreases, the amount of generation of NO _X with respect to the combustion amount of the entire burner is also small.

FIGS. 3 and 4 show another embodiment of a burner to which the fuel gas combustion method of the present invention is applied. The burner of this embodiment is a first burner for burning a fuel-rich mixture.
Are disposed on both sides, and a second burner section 4b for burning a fuel-lean mixture is provided between the first burner sections 4a. In this burner, the burner part 4
“a” forms a space between the side wall 7 and the tip ejection section 6 provided with a slit-shaped flame hole 5a on the upper side, which is thin.
In the burner section 4b, a ribbon 8 is provided at the tip to form a large number of flame holes 5b. 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.

FIG. 5 shows another embodiment of a burner to which the fuel gas combustion method of the present invention is applied. The burner of this embodiment has a burner portion 4a in the configuration of FIGS.
In place of the slit-shaped flame hole 5a, a ribbon 10 is provided at the front end in the same manner as the burner 4b to form a large number of flame holes 5a, a sleeve flame hole 9 and an outer space for forming a sleeve flame. Are formed.

In such a configuration, a plurality of units can be arranged side by side as an installation unit to constitute a burner having a desired combustion amount, and the burner portion 4b is sandwiched between the first burner portions 4a on both sides. While maintaining the configuration
As in the embodiment shown in FIG. 1 and FIG.
A plurality of b may be alternately and continuously arranged in a row to form a burner.

When the method of the present invention is applied to the burner having the above-described structure, in addition to the above-described operation similar to that of the structure shown in FIGS. 1 and 2, mixing in the flame holes 5a and 5b formed by the ribbons 8 and 10 is performed. The generation of noise can be further reduced by the rectifying action of the air, and in the case of forming the sleeve flame 11 in the burner 4a, the flame 12a of the burner 4a itself and the flame 12b of the burner 4b are further stabilized. Can be planned.

Next, FIG. 6 shows another embodiment of a burner to which the combustion method of the present invention is applied. In the burner of this embodiment, a large number of flame holes are formed by the ceramic plate 13. That is, the ceramic plate 13 has a plurality of flame holes arranged in a straight line 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. Second
The flame holes 14b of the flame hole group B are the flame holes 14a of the first flame hole group A.
The diameter is made smaller than that and the number is increased. That is, in the illustrated example, the second flame hole group B is composed of a large number of small diameter flame holes 14b arranged in two rows. And, the flame holes 14a of these first and second flame hole groups A and B,
14b, 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 second flame hole group B becomes In addition to the above-described combustion of excess air and the combustion subdivided by a large number of small-diameter flame holes 14b, the flame 15
generation of the NO _X temperature b is cooler during is further reduced. Further, 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, as in the above-described embodiment, so that the lift and the oscillating combustion hardly occur.

Although 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 can also be set as the structure arrange | positioned like this.

In the burner of the above embodiment, the burner sections 1a and 1b or the flame holes of the flame hole groups A and B are set in advance to a fuel-rich mixture or a fuel-lean mixture. Although it is configured to supply, any of them may be configured to supply and burn as required.

Next, FIG. 7 shows the result of implementing the fuel gas combustion method of the present invention. The results of this experiment are as follows. In the burner 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 the value indicated by the horizontal axis. This graph shows the amount of NO _X generated when the air is mixed and burned while adjusting the air ratio of the fuel-lean mixture so that 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 air ratio shown is a value including the cooling air when the cooling air flows outside the burner, and the air ratio in parentheses is a value not including the cooling air.

As shown in FIG. 7, by applying the combustion method of the present invention, it is understood that the generation amount of the NO _X compared to conventional general Bunsen burner is greatly reduced.

FIG. 8 shows an example of a flame lift limit of a burner section or a group of flame holes for supplying a fuel-lean mixture in comparison with the other methods when the method of the present invention is applied. .

A is a burner as described above to which the method of the present invention is applied, in which a fuel-lean mixture is supplied only to the burner portion or the burner hole group on one side and the burner portion or the burner group on the other side. FIG. 4 shows a lift limit in the case where the flame holding of the fuel-rich mixture is not carried out by the flame, that is, when the method of the present invention is not applied, and this limit is about λ = 0.7. On the other hand, B indicates a lift limit in a conventional general Bunsen burner having a flame holding mechanism, and this limit is about λ = 1.3. C indicates the lift limit in the one side burner portion or the flame hole group when the present invention is applied, and λ is about 3.0.

As described above, in the method of the present invention, compared with the conventional general Bunsen burner, the combustion of high excess air can be performed more stably, and the NO
_X can be reduced.

In the embodiment, the burners 1a and 4a have been described as the first burners, and the burners 1b and 4b have been described as the second burners.
Similar effects can be expected even if the burners b and 4b are used as the first burners.

[0039]

As described above, according to the present invention,
Since simultaneously burning the fuel rich first fuel gas and a fuel lean second fuel gas, it is possible to greatly reduce the occurrence of NO _X, the fuel lean mixture is poor flame stability alone Combustion of excess air can be maintained with a stable flame by combustion of a fuel-rich mixture, and combustion of excess air can be stabilized.
Generation of noise can be suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a burner which is an embodiment of a fuel gas combustion method of the present invention.

FIG. 2 is a diagram illustrating a combustion state of a burner in FIG. 1;

FIG. 3 is a perspective view showing another embodiment of the burner according to the present invention.

FIG. 4 is a sectional view illustrating a combustion state of the burner of FIG. 3;

FIG. 5 is a sectional view showing another embodiment of the burner according to the present invention.

FIG. 6 is a perspective view showing a configuration of a flame hole portion of another embodiment of the burner according to the present invention.

7 is a diagram of the NO _X generation amount due to the combustion process of the fuel gas of the present invention shown in comparison with conventional Bunsen burner.

FIG. 8 is a diagram showing a comparative example of a flame lift limit of a burner portion or a group of flame holes for supplying a fuel-lean mixture by the fuel gas combustion method 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 burner hole 3a, 3b flame 5a, 5b burner hole 12a, 12b flame 13 ceramic Plate 14a, 14b Flame hole 15a, 15b Flame

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takao Takagi 201 Nishi-Kashiwara Nitta, Fuji City, Shizuoka Prefecture Inside Takagi Sangyo Co., Ltd. In-company (72) Inventor Shigetoshi Akiyama 201 Nishi-Kashiwara Nitta, Fuji City, Shizuoka Prefecture Inside Takagi Sangyo Co., Ltd. (56) References JP-A-1-219406 (JP, A) JP-A-52-28028 (JP, A JP-A-62-108904 (JP, A) JP-A-49-133931 (JP, A) JP-A-3-247908 (JP, A) JP-A-2-115627 (JP, U) (58) Field (Int. Cl. ⁷ , DB name) F23C 11/00 330 F23D 14/08

Claims (2)

(57) [Claims] A fuel rich fuel gas and a fuel rich fuel
A method of burning fuel gas which uses gas combustion in combination, wherein the first burners are arranged at regular intervals.
The second burner section is arranged within the interval of the first burner section.
Thereby, the first and second burners are alternately arranged.
And the first burner part is arranged on the outer part
A burner is formed, and the first burner part has a large number of circular or square flame holes.
The first burner group is formed regularly, and the second burner portion is larger than the burners of the first burner group.
A circular or square flame hole is regularly formed to form a second flame.
The second group of flame holes has a total flame hole area of the second group.
The first flame hole group is set to be larger than the first flame hole group and is separated from the second flame hole group.
A rich first fuel gas is supplied, and the second flame hole group is supplied with a larger amount of fuel than the first fuel gas.
The second fuel gas, which is rich and has a high air ratio, is
The first burner group and the second burner section are supplied separately from the first flame hole group .
Supply cooling air from the first burner section and the second burner section.
From the total amount of fuel gas supplied to the burner section 2
In many cases, the flame holding due to the combustion of the fuel rich first fuel gas increases.
Wherein the combustion of the second fuel gas lean in fuel is stabilized . 2. The first group of holes and the second group of holes.
The combustion process of claim 1 wherein the fuel gas characterized by the formation lower child in a single ceramic plate.