JPH0886413A - Premixing combustion burner - Google Patents

Abstract

PURPOSE: To achieve a lower NOx designing with better combustion by making a gas ratio of a premixed gas blown from a porous periphery part higher than that of a premixed gas blown at a center part. CONSTITUTION: On the base side of a mixing section 2 ahead of a porous plate 1, a fuel gas is mixed with air for combustion at such a ratio as to ensure the optimum combustion when combustion is made at the center part of a flame and a premixed gas mixed is branched into the center part and a periphery part. The premixed gas sent to the center part is blown out as intact from the porous plate 1 to be burned at the center part of the flame, the premixed gas sent to the periphery part is mixed with the fuel gas to be introduced from a fuel gas introduction pipe 6 for adjusting combustion. The ratio of the gas is raised to such a rate as to ensure the optimum combustion when burning is made at the periphery part of the flame and then, the gas is blown out from the porous plate 1 to be burned at the periphery part of the flame. Thus, the optimum combustion is obtained at either of the periphery part or the center part of the frame.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a premixed combustion burner capable of improving the combustibility of the entire flame.

[0002]

2. Description of the Related Art One of the forms of a burner is a premixed combustion burner in which fuel gas and combustion air are premixed and then burned. In the case of the premixed combustion burner, the combustion state is improved by adjusting the mixing ratio of the fuel gas and the combustion air and further mixing as uniformly as possible to achieve low NOx. Further, a technique for improving the combustion state by changing the flame formation by devising the shape and arrangement of the gas injection holes of the burner plate has been developed.

[0003]

The problem to be solved by the present invention is to further improve the combustion state, reduce NOx, and improve the combustion efficiency.

[0004]

[Means for Solving the Problems] Fuel gas and combustion air are premixed on the root side of a mixing section in front of a porous plate, a premixed gas is blown from the porous plate, and the blown premixed gas is burned. In the premixed combustion burner described above, the gas ratio of the premixed gas blown out from the peripheral portion of the porous plate was made higher than the gas ratio of the premixed gas blown out from the central portion of the porous plate.

[0005]

The flame is burned in the air, and since the air surrounds the flame, the ratio of the air in the peripheral portion of the flame is higher than that in the central portion. Therefore, the optimum mixing ratio of the premixed gas differs between the central part and the peripheral part of the flame.
Therefore, rather than aiming to make the premixed gas have a uniform concentration, the gas ratio of the premixed gas blown out from the peripheral edge of the porous plate should be adjusted so that it is higher than the central part where the air around the flame is used. By attaching,
Good combustion is obtained at both edges.

[0006]

An embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, the side having the porous plate (1) made of ceramic is the tip side of the burner, and the combustion is performed at the tip of the plate. On the front side of the plate, a cylindrical mixing portion (2) for mixing the fuel gas and the combustion air is provided,
A fuel gas introduction pipe (3) and a combustion air introduction pipe (4) are connected to the base side of the mixing section. An inner cylinder (5) concentric with the mixing section cylinder is provided near the plate in the cylindrical mixing section to divide the mixing section into a central portion and a peripheral portion so that the premixed gas reaches the plate by dividing the central portion and the peripheral portion. Then, the combustion adjusting fuel gas introduction pipe (6) is connected to the outer peripheral side of the inner portion of the mixing section.

On the root side of the mixing section, the fuel gas and the combustion air are mixed in such a ratio that an optimum combustion can be obtained when the combustion is carried out in the central part of the flame, and the mixed premixed gas is mixed with the central part. It is branched to the peripheral portion. The premixed gas sent to the center is directly blown out from the plate and burns at the center of the flame, and the premixed gas sent to the peripheral part is the fuel gas introduced from the combustion adjustment fuel gas introduction pipe. After being mixed with the gas, the gas ratio is increased to a ratio such that optimum combustion is obtained when combustion is performed at the peripheral edge of the flame, and then the gas is blown out from the plate and burns at the peripheral edge of the flame. Since the central portion of the flame is surrounded by the flame, air is not supplied from the surroundings, but the peripheral portion of the flame is in contact with the outside air, so the air around the flame is also used for combustion. By setting the gas ratio of the flame peripheral portion higher than that of the flame central portion, optimum combustion can be obtained in both the flame peripheral portion and the flame central portion.

2, 3, and 4 show another embodiment of the present invention, in which a fuel gas introducing pipe (3) and a combustion air introducing pipe (4) are provided on the base side of the mixing section in each drawing. Are connected. In FIG. 2, a ring-shaped combustion adjusting fuel introducing section (7) for introducing fuel into the peripheral portion of the mixing section (2) and a combustion adjusting fuel introducing section connected to the combustion adjusting fuel introducing section for introducing fuel gas. A fuel introduction pipe (6) is provided. When combustion is performed, the fuel gas and the combustion air are supplied on the base side of the mixing unit in such a ratio that optimum combustion can be obtained when the combustion is performed in the center of the flame. After that, the fuel gas is introduced into the peripheral portion and the gas ratio in the peripheral portion is set higher than that in the central portion, so that the entire combustion is uniform and good combustion is performed.

In the case of FIG. 3, a combustion adjusting air introducing section (8) for introducing air into the central portion of the mixing section and a combustion adjusting air introducing section for connecting the combustion adjusting air introducing section and introducing combustion air. A tube (9) is provided. When combustion is performed, the fuel gas and the combustion air are mixed on the root side of the mixing portion in such a ratio that optimum combustion can be obtained when the combustion is performed in the peripheral portion of the flame. After that, air is supplied to the central portion and the gas ratio in the central portion is made lower than that in the peripheral portion, so that the entire combustion is uniform and good combustion is performed.

In the case of FIG. 4, the mixing section is branched into two in the middle, one of which is connected to the center of the plate and the other of which is connected to the plate so as to enclose the tube connected to the center. A combustion adjusting air introducing pipe is connected to the side connected to. When combustion is performed, the fuel gas and the combustion air are mixed on the root side of the mixing portion in such a ratio that optimum combustion can be obtained when the combustion is performed in the peripheral portion of the flame. After that, air is introduced into the central portion and the gas ratio in the central portion is set lower than that in the peripheral portion, so that the entire combustion is uniform and good combustion is performed.

[0011]

By carrying out the present invention, optimal combustion is performed in both the central portion and the peripheral portion of the flame, the combustion efficiency is improved by improving the combustibility, and the efficiency of the burner is improved.
Fuel gas can be made more efficient and low NOx combustion can be performed.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an embodiment of the present invention.

FIG. 2 is a schematic diagram of another embodiment of the present invention.

FIG. 3 is a schematic diagram of another embodiment of the present invention.

FIG. 4 is a schematic diagram of another embodiment of the present invention.

[Explanation of symbols]

 1 plate 2 mixing section 3 fuel gas introduction tube 4 combustion air introduction tube 5 inner cylinder 6 combustion adjustment fuel gas introduction tube 7 combustion adjustment fuel introduction section 8 combustion adjustment air introduction section 9 combustion adjustment air introduction tube

Claims (4)

[Claims] 1. A premixed combustion in which fuel gas and combustion air are premixed on the base side of the mixing section in front of the porous plate, premixed gas is blown out from the porous plate, and the blown out premixed gas is burned. In the burner, the premixed combustion burner is characterized in that the gas ratio of the premixed gas blown out from the peripheral portion of the porous plate is made higher than the gas ratio of the premixed gas blown out from the central portion of the porous plate. 2. The premixed combustion burner according to claim 1, wherein an inner cylinder that divides the premixed gas blown out from the porous plate into a central portion and a peripheral portion is provided near the inner tip of the mixing portion and is sent to the peripheral portion. Additional supply of fuel gas to premixed gas, or
A premixed combustion burner characterized in that the gas ratio of the premixed gas sent to the peripheral portion is made higher than that of the central part by additionally supplying combustion air to the premixed gas sent to the central portion. 3. The premixed combustion burner according to claim 1, wherein a ring-shaped fuel gas supply section for additionally supplying fuel gas to the peripheral edge of the porous plate is provided near the inner tip of the mixing section, and is fed to the peripheral edge. By supplying fuel gas to the premixed gas,
A premixed combustion burner characterized in that the gas ratio of the premixed gas sent to the peripheral portion is made higher than that in the central portion. 4. The premixed combustion burner according to claim 1, wherein a combustion air supply section for additionally supplying combustion air to the central part of the porous plate is provided near the inner end of the mixing section, and the premixed combustion burner is supplied to the central part. A premixed combustion burner characterized in that the gas ratio of the premixed gas sent to the peripheral portion is made higher than that in the central portion by supplying combustion air to the mixed gas.