JPH04126906A - Low-nox burner - Google Patents

Abstract

PURPOSE:To reduce the generation of NOx without interfering with the combustion efficiency and stabilize the combustion by providing a header in which fuel injection nozzles are arranged unevenly in a circle around the axis of the header. CONSTITUTION:A plurality of fuel injection nozzles formed in a header 1 include two having a larger bore. These nozzles are so arranged that, in the flaming regions formed on the right and the left of the center of the header, fuel is injected in excess of the average and hence produces a little surplus, whereas, in the flaming regions above and under the center, a surplus of air is produced. Therefore, downstream from the burner, the combustion produces a flame which is asymmetric with portions forming flaming regions oversupplied with fuel and the other portions, flaming regions oversupplied with air, that is, formation of a flame produced in part by concentrated combustion and in part by thin combustion. This decreases the average temperature of the flame and hence restrains the generation of NOx.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a burner that burns fuel such as gas, oil, or pulverized coal, and particularly relates to a burner that suppresses the generation of nitrogen oxides NOX without reducing combustion efficiency. About the burner you get.

[Conventional technology]

Burners for burning gas, heavy oil, or pulverized coal are widely used, and in conventionally known burners, the header with the nozzle for fuel injection is either a body or a substantially completely rotating body such as a truncated cone. The nozzles were arranged in an annular shape on the side or front of the rotating body, and the spray angle and nozzle diameter were also uniform.

Such conventional burners have a problem in that when trying to increase combustion efficiency, NOx is generated at a high concentration.

This NOx has recently become a problem from the viewpoint of environmental conservation, and there is a strong demand to suppress its generation.

[Problems to be Solved by the Invention] The present invention has been made to solve the above-mentioned problems, and its purpose is to reduce the generation of NOx without impairing combustion efficiency, and to achieve a stable The object of the present invention is to provide a burner that can produce combustion.

[Means for Solving the Problems and Their Effects] The above object is to make the radial distribution of the jets of fuel and air inside the burner non-uniform, so that a portion with relatively excess air and
This is achieved by means of a burner that generates an excess of fuel and thereby burns the fuel in a concentrated manner.

More specifically, the above object is achieved by using a burner in which the arrangement, dimensions, or injection angle of the nozzle that injects fuel from the header is non-uniform in the circumferential direction around the central axis of the header and/or air cone. achieved.

The present invention can be applied to gas burners, oil burners, and pulverized coal burners.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a burner according to the present invention;
FIG. 2 is a front view thereof, FIGS. 3 to 5 are front views showing the shape of the header used in another embodiment, and FIGS. 6 and 7 are side views of the header shown in FIG. 5. FIG. 8 is a graph showing the NOx reduction effect of the gas burner according to the present invention.

It should be noted that these drawings are simplified to illustrate the principles of the present invention, or may be applied to all types of known gas burners, oil burners, and pulverized coal burners, which are actually more complex in construction.

In Figure 1, 1 is a header equipped with a nozzle for injecting fuel, 2 is an air cone, 3 is a fuel supply pipe, and 4 is a connection between header 1 and air to form an air flow path and stabilize the flame. An air plate 5 provided between the cones is an air outlet.

In the embodiment shown in FIGS. 1 and 2, only two of the plurality of fuel injection nozzles provided in the header 1 have a large diameter.

For this reason, in the flame areas on the left and right of the center of the header in Figure 2, more fuel is injected than the average value, so there is a slight excess of fuel, and conversely, in the flame areas in the vertical direction there is an excess of air. .

For this reason, the flame generated by combustion becomes asymmetrical, with a flame region containing excess fuel and a flame region containing excess air coexisting, and concentrated combustion occurs in front of the burner, which lowers the average temperature of the flame and suppresses the generation of NOx. will be done.

The NOx reduction effect of the gas burner according to the present invention is shown in FIG. It can be seen from this figure that according to the invention, the NOx generation can be reduced to half that of the known burner.

In the header 11 shown in FIG. 3, the fuel injection nozzles are arranged in an elliptical ring shape, and in the header 12 shown in FIG. , and the nozzle diameters therebetween are arranged so that they become smaller from left to right.

In the devices shown in FIGS. 5 to 7, the air injection angle can be changed depending on the location.

In short, the gist of the present invention is to make the streamline distribution of the fuel injected from the header non-uniform in the circumferential direction around the central axis of the header, thereby eliminating the excessive flame area of the fuel and the excessive flame area of the air. The purpose of the present invention is to suppress the generation of NOx without reducing the combustion efficiency by reducing the temperature of the flame through its concentrated combustion.

In order to achieve this object, the object of the present invention can be achieved not only by the above-mentioned embodiments but also by making the pitch of the fuel injection nozzles uneven, or by using auxiliary nozzles together with the main header. It should be obvious. Therefore, the structure of the present invention is not limited to the embodiments in progress, but encompasses all embodiments that can be easily conceived by those skilled in the art from the above description.

Incidentally, according to the present invention, the fuel combustion efficiency is maintained the same as that of conventionally known burners.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a burner according to the present invention;
FIG. 2 is a front view thereof, FIGS. 3 to 5 are front views showing the shape of the header used in another embodiment, and FIGS. 6 and 7 are side views of the header shown in FIG. 5. and a bottom view, and FIG. 8 is a graph showing the NOx reduction effect of the gas burner according to the present invention.

Claims (1)

[Claims] (1) A header having a fuel injection nozzle, an air cone having a flame emitting port and surrounding the header, and forming an air flow to surround the fuel injected from the header. In a burner equipped with an air plate, the arrangement of the fuel injection nozzle of the header is
The above burner is circumferentially non-uniform around the central axis of the header. (2) The burner according to claim 1, wherein the fuel injection nozzles are arranged in an annular shape around the central axis of the header, and the opening diameters of the nozzles are different. (3) The burner according to claim 2, wherein the fuel injection nozzles are arranged so that the opening diameter of the nozzles decreases sequentially from one end of the circle on which the fuel injection nozzles are arranged toward the other end. (4) The burner according to claim 1, wherein at least one of the fuel injection nozzles has a larger opening diameter than the other nozzles. (5) The burner according to claim 1, wherein the fuel injection nozzles are arranged in an elliptical ring shape. (6) The burner according to claim 1, wherein the fuel injection nozzles have different fuel injection angles. (7) The burner according to claim 1, wherein the intervals between adjacent fuel injection nozzles are unequal. (8) The burner according to any one of claims 1 to 7, wherein an auxiliary fuel injection nozzle is provided together with the main header. (9) The burner according to any one of claims 1 to 8, wherein the fuel is gas. (10) The burner according to any one of claims 1 to 8, wherein the fuel is oil. (11) The burner according to any one of claims 1 to 8, wherein the fuel is pulverized coal.