JP2001153318A - LOW NOx BURNER - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low NOx burner for a high-temperature furnace which can prevent the stationary combustion from being damaged by the deformation of a fuel injection nozzle or an oxidizing agent injection nozzle caused by the heating. SOLUTION: The low NOx burner injects the fuel from the fuel injection nozzle 13 forward of a burner tile 12 mounted on a forward part of the burner, and injects the oxidizing agent from the oxidizing agent injection nozzle 14 to implement the combustion. A projecting plate 15 to cover an upper portion of the fuel injection nozzle 13 or the oxidizing agent injection nozzle 14 is provided in a forward projecting direction from a front surface of the burner tile 12 on a part located above the fuel injection nozzle 13 or the oxidizing agent injection nozzle 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low NOx used in various high-temperature furnaces such as a glass melting furnace and an incineration ash melting furnace.
The structure of the burner.

[0002]

In general, burners used in high-temperature furnaces whose operating temperatures exceed 1000 ° C., such as glass melting furnaces and incineration ash melting furnaces, are required to reduce NOx. Some fuels and oxidizers (air, oxygen, oxygen-enriched air) are injected into a furnace at a high speed of, for example, 50 m / s or more to perform combustion.

FIG. 11 is a side view showing a conventional low NOx burner for a high-temperature furnace, and FIG. 12 is a front view thereof.

In FIGS. 11 and 12, low NOx
The burner 1 has a burner tile 3 formed of a refractory material attached to a front portion of a burner main body 2, a fuel injection hole 3 </ b> A formed at a central portion of a front surface of the burner tile 3, and an oxidant injection hole formed at four corners. Holes 3B are respectively formed.

The low NOx burner 1 is mounted on the furnace wall of a high-temperature furnace, and performs combustion by directly injecting fuel and oxidant from the fuel injection holes 3A and the oxidant injection holes 3B into the furnace. At this time, the reduction of NOx is realized by the self-exhaust gas recirculation effect of performing combustion by involving the combustion gas having a low oxygen concentration in the furnace by the ejection energy of the fuel and the oxidant.

[0006] In such a low NOx burner, a primary oxidant for combustion is injected from an oxidizing agent injection hole provided at an outer peripheral portion of a fuel injection hole, and oxidizing agent injection formed at four corners of a burner tile. There is also a so-called two-stage combustion burner that performs a two-stage combustion by injecting a secondary oxidant for combustion from a hole.

[0007] In the case of such a low NOx burner for a high-temperature furnace, the surface of the burner tile 3 facing the inside of the furnace is heated at a high temperature by flame or radiant heat in the furnace.

For this reason, in the conventional low NOx burner, the periphery of the fuel injection holes 3A and the oxidizing agent injection holes 3B are melted away, and the opening area is increased as shown in FIG. In some cases, as shown in FIG. 13B, the melted portion 3a at the top of the injection port may hang down.

In this case, the shape of the fuel injection holes 3A and the oxidizing agent injection holes 3B change the shape of the flame and the direction of the injection, thereby deteriorating the temperature distribution and the NOx emission concentration in the furnace. Problems arise.

Further, as shown in FIG. 13 (a), when the opening area of the fuel injection hole 3A or the oxidant injection hole 3B becomes large, incomplete combustion due to excessive fuel supply occurs, There is a problem that the combustion efficiency is reduced and the furnace temperature is reduced due to excessive supply of the gas.

Further, as shown in FIG. 13 (b), when the upper part of the injection hole of the fuel injection hole 3A or the oxidizing agent injection hole 3B melts and hangs down, the opening area of the injection hole becomes small, and the fuel injection hole becomes small. Problems such as a decrease in the furnace temperature due to the shortage and the occurrence of incomplete combustion due to the lack of oxygen occur.

Further, in a low NOx burner configured as shown in FIGS. 11 and 12, as shown in FIG.
A recirculation region f of the combustion gas in the furnace is formed around the fuel injection holes 3A and the oxidant injection holes 3B.

In the recirculation region f, the combustion gas in the furnace flows along the surface of the burner tile 3 by being attracted by the fuel or the oxidizing agent injected from the injection port, so that the suspended matter in the furnace is generated. Adheres to the surface of the burner tile 3, and furthermore, the attached suspended matter w is melted by heating and flows into the peripheral portion of the injection port, whereby the same phenomenon as in the state of FIG. 13B occurs.

The present invention relates to the conventional low NOx as described above.
This is to solve the problem of the burner. That is, an object of the present invention is to provide a low NOx burner for a high-temperature furnace, which can prevent a steady combustion state from being damaged by deformation due to heating of a fuel injection hole or an oxidant injection hole.

[0015]

SUMMARY OF THE INVENTION According to the first aspect of the present invention, a low NO
In order to achieve the above object, the x burner injects fuel from a fuel injection hole in front of a refractory attached to a front portion of the burner and injects an oxidant from an oxidant injection hole to perform combustion. In the burner, in a portion located above the fuel injection hole or the oxidant injection hole on the front surface of the refractory, a projecting member that covers the fuel injection hole or the oxidant injection hole projects forward from the front surface of the refractory. It is characterized by being provided in.

The low NOx burner according to the first invention is:
The fuel and oxidizer are directly injected into the furnace through the fuel injection holes and oxidizer injection holes that are attached to the furnace wall of the high-temperature furnace and open to the front of the refractory, and the fuel and oxidizer are ejected. The self-exhaust gas recirculation effect, which involves burning the low oxygen concentration combustion gas in the furnace by energy and burning,
Achieve low NOx.

In the low NOx burner, when performing combustion, the recirculating flow of the combustion gas tends to contact the upper surface of the fuel injection hole or the oxidant injection hole of the refractory by the projecting member. Because of the obstruction, the suspended matter in the furnace flowing along with the recirculation flow is prevented from adhering to the surface of the refractory above the fuel injection hole or the oxidant injection hole.

Further, in the low NOx burner, since the projecting member is provided so as to cover the upper side of the fuel injection hole or the oxidizing agent injection hole, the refractory material around the fuel injection hole or the oxidizing agent injection hole is provided. Since the surface of the refractory blocks some of the flame and the radiant heat from the furnace, the surface temperature of the portion of the refractory located above the fuel injection holes or oxidizer injection holes is suppressed, and the melting of this portion is prevented. Prevents damage and dissolution of adhered suspended matter.

Further, since the surface area of the refractory at a portion located above the fuel injection hole or the oxidant injection hole is reduced by providing the protruding member, even if that portion is melted down, Enlargement and closing of the opening area of the fuel injection hole or the oxidant injection hole can be small.

In the first aspect, a so-called two-stage combustion burner may be provided by providing a primary oxidant injection hole for injecting a primary oxidant for combustion so as to surround the fuel injection hole. .

As described above, according to the first aspect,
The projecting members suppress the adhesion of suspended matter,
Since the temperature rise in the periphery of the refractory surface where the fuel injection holes or the oxidant injection holes are open is suppressed, melting of the refractory and melting of the adhered suspended matter are suppressed, and the fuel injection holes or the oxidizing agent are oxidized. The opening area of the agent injection hole can be prevented from being enlarged or blocked by deformation.

According to a second aspect of the present invention, in order to achieve the above object, in addition to the configuration of the first aspect, the projecting member is formed of a material different from the refractory. It is characterized by.

According to the low NOx burner according to the second aspect of the present invention, the projecting member is formed of a material having a higher fire resistance or a corrosive property against the molten material than the refractory material of the refractory, thereby melting the projecting member itself. To prevent the fuel injection hole or the oxidant injection hole from being closed.

According to a third aspect of the present invention, there is provided a low NOx burner according to the first aspect, wherein the lower surface of the protruding member extends from the distal end to the proximal end in contact with the refractory. It is characterized in that it is inclined to descend.

According to the low NOx burner of the third aspect, the lower surface of the protruding member is inclined so as to descend toward the base end, so that the fuel is injected from the fuel injection hole or the oxidant injection hole. Since the flow of the fuel or the oxidant flows along the inclined surface of the protruding member, it becomes difficult to form a region where the recirculation flow flows above the respective openings of the fuel injection holes or the oxidant injection holes, so that the floating It is possible to more effectively prevent the material from adhering to the portion of the refractory surface located above the fuel injection hole or the oxidant injection hole, thereby preventing the fuel injection hole or the oxidant injection hole from being blocked.

According to a fourth aspect of the present invention, there is provided a low NOx burner according to the first aspect, wherein an upper surface of the projecting portion descends from a central portion toward a side portion. It is characterized by being inclined.

According to the low NOx burner according to the fourth aspect of the present invention, even if the floating material in the furnace attached to the portion above the projecting member on the front surface of the refractory is melted and fluidized, the molten floating material Flows sideways from above the fuel injection hole or the oxidant injection hole along the inclined surface of the upper surface of the protruding member, so that the dissolved suspended matter flows in and the fuel injection hole or the oxidant injection hole is closed. Can be prevented.

[0028]

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

FIG. 1 is a side view showing a first example of a low NOx burner according to the present invention, and FIG. 2 is a front view thereof.

1 and 2, a low NOx burner 10 has a burner tile 12 formed of a refractory material attached to a front portion of a burner main body 11, and a fuel injection into a central portion of a front surface of the burner tile 12. A hole 13 is opened, and a pair of oxidant injection holes 14 are opened on both sides of the hole so as to sandwich the fuel injection hole 13.

The front side of the burner tile 12 is positioned above the fuel injection holes 13 and the oxidizing agent injection holes 14 from the front side of the burner tile 12 (to the right in FIG. 1).
Protruding plate 1 formed of a refractory material so as to protrude
5 are provided.

The low NOx burner 10 is mounted on a furnace wall of a high-temperature furnace, and is provided with fuel injection holes 13 and oxidizing agent injection holes 1.
4, the fuel and oxidant are directly injected into the furnace to perform combustion, and the self-exhaust gas recirculation effect of performing combustion by involving the low-oxygen-concentration combustion gas in the furnace by the fuel and oxidant ejection energy. As in the conventional low NOx burners 11 and 12, NOx reduction is realized.

The fuel injected from the fuel injection hole 13A contains a trace amount of oxidant, and the fuel injected from the fuel injection hole 14A
In some cases, the oxidant injected from the fuel contains a small amount of fuel.

The low NOx burner 10 is similar to that shown in FIG.
As shown in the figure, when performing the combustion, the recirculated flow f ′ of the combustion gas is blocked by the projecting plate 15, , The suspended matter flowing in the furnace on the recirculating flow f ′ is discharged to the fuel injection holes 13 and the oxidant injection holes 14.
On the upper tile surface.

Therefore, the suspended matter in the furnace attached to the burner tile 12 is melted, and the fuel injection holes 13 and the oxidant injection holes 1 are melted.
4 hardly occurs.

Further, the low NOx burner 10 is
5 is provided so as to cover above the fuel injection holes 13 and the oxidant injection holes 14, so that the surface of the burner tile 12 around the fuel injection holes 13 and the oxidant injection holes 14 receives a flame or a furnace. Since a part of the radiant heat from the inside is blocked, a rise in the surface temperature of a portion of the burner tile 12 located above the fuel injection hole 13 and the oxidant injection hole 14 is suppressed, thereby causing erosion and damage of this portion. Melting of the adhered suspended matter is suppressed.

Since the protruding plate 15 is provided, the surface area of the burner tile 12 located above the fuel injection holes 13 and the oxidizing agent injection holes 14 becomes small, so that the burner tiles 12 The fuel injection hole 1
3 and the degree of the degree of blockage and enlargement of the opening area of the oxidizing agent injection hole 14 can be reduced.

In the low NOx burner 10,
The protruding plate 15 may be formed of a refractory material of the same material as that of the burner tile 12.
By molding with a material having higher fire resistance and corrosiveness to a molten material than the burner tile 12, it is possible to prevent the protrusion plate 15 itself from being melted and damaged.

FIG. 4 is a side view showing a second example of the low NOx burner according to the present invention, and FIG. 5 is a front view thereof.

In FIGS. 4 and 5, the low NOx burner 20 is similar to the low NOx burner 10 of the above-described first example.
A protruding plate 25 formed of a refractory material is provided above the fuel injection holes 13 and the oxidant injection holes 14 on the front surface of the burner tile 12 so as to protrude forward (rightward in FIG. 4) from the front surface of the burner tile 12. Is provided.

The lower surface of the projecting plate 25 is
An inclined surface 25 a descends from the distal end of the protruding plate 25 toward the base end side in contact with the front surface of the burner tile 12.

Since the low NOx burner 20 is provided with the protruding plate 25, similarly to the low NOx burner 10 of the first example, the opening area due to the erosion of the fuel injection holes 13 and the oxidant injection holes 14 is formed. Can be prevented from being enlarged or blocked.

Further, the low NOx burner 20
As shown in FIG. 6, the flow of the fuel and the oxidant injected from the fuel injection holes 13 and the oxidant injection holes 14, The flow along the inclined surface 25a of the plate 25 makes it difficult to form a region in which the recirculation flow flows above the respective openings of the fuel injection holes 13 and the oxidizing agent injection holes 14. This prevents the fuel injection holes 13 and the oxidant injection holes 14 from being blocked, by more effectively preventing adhesion to the fuel injection holes 12.

In the second example, the projecting plate 25
The inclination angle of the inclined surface 25a is set to be the same as the inclination angle of the upper part of the fuel and the oxidant injected from the fuel injection holes 13 and the oxidant injection holes 14, so that the above-described angle is further improved. Such effects are exhibited.

FIG. 7 is a side view showing a third example of the low NOx burner according to the present invention, and FIG. 8 is a front view thereof.

7 and 8, the low NOx burner 30 is similar to the low NOx burner 10 of the first example, and is similar to the low NOx burner 10 of the first embodiment.
A protruding plate 35 formed of a refractory material is provided above the fuel injection holes 13 and the oxidant injection holes 14 on the front surface of the burner tile 12 so as to protrude forward (rightward in FIG. 7) from the front surface of the burner tile 12. Is provided.

The protruding plate 35 is formed on its upper surface with an inclined surface 35a which is inclined downward from the center toward the side (in the horizontal direction in FIG. 8).
It is molded so that the shape seen from the front becomes a roof type.

Since the low NOx burner 30 is provided with the protruding plate 35, similarly to the low NOx burner 10 of the first example, the opening area due to the erosion of the fuel injection holes 13 and the oxidant injection holes 14 is formed. Can be prevented from being enlarged or blocked.

Further, the low NOx burner 30
Even if the suspended matter in the furnace attached to the portion above the protruding plate 35 on the front surface of the burner tile 12 is melted and fluidized,
The melted suspended matter is formed on the inclined surface 35a on the upper surface of the protruding plate 35.
Flows along the fuel injection holes 13 and the oxidant injection holes 14 from above, so that the melted suspended material flows in and the fuel injection holes 13 and the oxidant injection holes 14 are deformed or closed. Can be prevented.

In the third example, the projecting plate 35
May be inclined so as to descend from the distal end side to the proximal end side as in the second example.

Here, in the first to third examples, as shown in the drawings, the case where the present invention is applied to a low NOx burner in which a fuel injection hole and an oxidizing agent injection hole are arranged in a horizontal direction with respect to each other will be described. However, the arrangement of the fuel injection holes and the oxidizing agent injection holes of the low NOx burner to which the present invention is applied is not limited to the above example. For example, as shown in FIGS. Injection hole 1
The present invention can also be applied to a low NOx burner 40 in which 3 ′ and the oxidizing agent injection holes 14 ′ are vertically arranged.

In this case, for each of the fuel injection hole 13 ′ and the oxidant injection hole 14 ′, the projecting plate 45 is connected to the fuel injection hole 13 ′ of the burner tile 12 ′ and the oxidant injection hole 1 ′.
4 ′ from the upper part (FIG. 10
At the right side in the drawing).

[Brief description of the drawings]

FIG. 1 is a side view showing a first example in an embodiment of the present invention.

FIG. 2 is a front view of the same example.

FIG. 3 is an explanatory diagram showing a state of a recirculation flow during combustion in the same example.

FIG. 4 is a side view showing a second example of the embodiment of the present invention.

FIG. 5 is a front view of the same example.

FIG. 6 is an explanatory diagram showing a state of a recirculation flow during combustion in the same example.

FIG. 7 is a side view showing a third example of the embodiment of the present invention.

FIG. 8 is a front view of the same example.

FIG. 9 is a front view showing another example of the mounting state of the protruding plate of the low NOx burner according to the present invention.

FIG. 10 is a side view of the same example.

FIG. 11 is a side view showing a conventional example.

FIG. 12 is a front view of the conventional example.

FIG. 13 is a partial side sectional view showing a state where a fuel injection hole and an oxidant injection hole of a conventional low NOx burner are melted and damaged.

FIG. 14 is an explanatory diagram showing a state of adhesion of suspended matter in a conventional example.

[Explanation of symbols]

 10, 20, 30, 40 ... low NOx burner 11 ... burner body 12, 12 '... burner tile (refractory) 13, 13' ... fuel injection hole 14, 14 '... oxidant injection hole 15, 25, 35, 45 ... Projecting plate 25a ... Slope 35a ... Slope f '... Recirculation flow

Claims (4)

[Claims] 1. A low NOx burner for injecting fuel from a fuel injection hole and injecting an oxidant from an oxidant injection hole to perform combustion in front of a refractory attached to a front portion of a burner, A projecting member that covers the fuel injection hole or the oxidant injection hole above the fuel injection hole or the oxidant injection hole is provided in a portion of the front surface located above the fuel injection hole or the oxidant injection hole, in a direction protruding forward from the front surface of the refractory. A low NOx burner characterized by the following. 2. The low NOx burner according to claim 1, wherein the projecting member is formed of a different material from the refractory. 3. The low NOx burner according to claim 1, wherein the lower surface of the protruding member is inclined so as to descend from a distal end side toward a base end side in contact with the refractory. 4. The low NOx burner according to claim 1, wherein an upper surface of the protruding portion is inclined so as to descend from a central portion toward a side portion.