JP2002089806A - Oxygen burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxygen burner capable of obtaining low luminous or non-luminous flame of large length without producing soot and preventing carbon from adhering on a nozzle portion. SOLUTION: The oxygen burner having a triple tubular structure comprises a primary oxygen channel 16 provided in a center tube 11, a fuel gas channel 15 provided between the center tube 11 and an inner tube 12, and a secondary oxygen channel 16 provided between the inner tube 12 and an outer tube 13. The end of the inner tube 12 is stuck out forward of the end of the center tube 11, so that fuel gas jetted out from a fuel gas nozzle 18, which is formed between the outer periphery of the center tube end and the inner periphery of the inner tube, is directed to a focal point F1 on the axis of the center tube 11. Further, the end of the outer tube 13 is stuck out forward of the end of the inner tube 12, so that secondary oxygen jetted out from a secondary oxygen nozzle 19, which is formed between the outer periphery of the inner tube end and the inner periphery of the outer tube, is directed to a focal point F2 on the axis of the center tube.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxygen burner, and more particularly to a flame-forming oxygen burner suitable for use as a heating source in a glass melting furnace.

[0002]

2. Description of the Related Art When an object to be heated is heated by a burner, there are a forced convection heat transfer system in which a flame is directly blown to the object to be heated and a radiant heat transfer system in which heat from the flame is transmitted by radiation. They are used differently depending on the properties and the like. For example, in a glass melting furnace, if a flame is directly sprayed on the molten glass, components that easily evaporate in the glass may evaporate due to local overheating, or the glass may be contaminated by the flame. The heat transfer method is not preferable, and a radiant heat transfer type burner is used.

[0003] Burner combustion flames are generally classified into high-intensity flames and low-intensity flames.
There are many floating soot particles, which are sources of high-intensity flames and transmit radiant heat to the object to be heated. Such a high-luminance flame forms a strong reducing atmosphere, while a low-luminance flame forms an oxidizing atmosphere. further,
It was difficult to obtain a flame having a relatively long flame length with a high-luminance flame, and difficult to obtain a flame having a long flame length with a low-luminance flame.

On the other hand, in order to obtain uniform product quality in a glass melting furnace, it is necessary to heat the molten metal uniformly.
It is considered that a flame having a long flame length is desirable for preventing local overheating. Therefore, in the conventional glass melting furnace, using a multi-tube burner having a structure that easily obtains a relatively long flame,
Usually, a high-intensity flame is formed.

[0005]

However, depending on the type of glass, for example, in the case of low alkali glass, the glass raw material, which is an oxide, dislikes a reducing atmosphere and dislikes contamination by soot. A high-luminance flame is unsuitable, and a low-luminance flame that does not generate soot and forms an oxidizing atmosphere is desired.

However, it is difficult to obtain a long flame with a low-luminance flame, and the combustion speed of fuel is higher than that of a high-luminance flame, and the temperature near the burner tip (nozzle) tends to increase. The adhesion of carbon to the part was a problem.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an oxygen burner which can obtain a long flame length while being a low-luminance flame or non-luminous flame without sooting and can prevent carbon from adhering to a nozzle portion. I have.

[0008]

In order to achieve the above object, an oxygen burner according to the present invention comprises a primary oxygen flow path inside a central pipe and a fuel gas flow between the central pipe and an inner pipe outside the central pipe. An oxygen burner having a triple pipe structure in which a secondary oxygen flow path is formed between the inner pipe and the outer pipe outside the inner pipe, wherein the tip of the inner pipe is located forward of the tip of the central pipe. And projecting the fuel gas ejected from the fuel gas ejection port formed between the outer periphery of the center tube tip and the inner periphery of the inner tube so as to focus on the axis of the center tube.
The tip of the outer tube is projected forward from the tip of the inner tube,
The ejection direction of the secondary oxygen ejected from the secondary oxygen ejection port formed between the outer periphery of the inner tube tip and the inner periphery of the outer tube is formed so as to be focused on the axis of the central tube. .

Further, the flow rate of the primary oxygen injected from the primary oxygen outlet at the tip of the primary oxygen flow path is in the range of 50 to 340 m / s in terms of 0 ° C. and 1 atm, and the primary oxygen is injected from the fuel gas outlet. It is characterized in that it is set at a higher speed than the flow velocity of the fuel gas.

[0010]

1 to 3 show an embodiment of an oxygen burner according to the present invention. FIG. 1 is a sectional side view and FIG.
3 is a sectional side view of the nozzle portion, and FIG. 3 is a sectional view taken along line III-III of FIG.

This oxygen burner has a triple tube structure in which a central tube 11, an inner tube 12 outside the tube, and an outer tube 13 outside the tube are concentrically arranged.
A primary oxygen flow path 14 is provided inside the central pipe 11 and the inner pipe 12.
A secondary oxygen flow path 16 is formed between the inner pipe 12 and the outer pipe 13, and a primary oxygen jet 17 is provided at the tip of the primary oxygen flow path 14. A fuel gas outlet 18 is provided between the outer periphery of the center tube tip and the inner periphery of the inner tube, and a secondary oxygen outlet 19 is provided between the outer periphery of the inner tube tip and the inner periphery of the outer tube.

The inside of the central pipe 11 has a straight pipe structure of substantially the same diameter, and the primary oxygen supplied to the primary oxygen flow path 14 passes through the central pipe and passes through the primary oxygen outlet 17 into a straight line. Spouts. The inner pipe 12 has a tip projecting forward (flame ejection direction) from the tip of the center pipe 11, and the opening diameter of the fuel gas outlet 18 is smaller than the inner diameter of the inner pipe 12 at the tip inner surface. A tapered conical surface 12a is provided. Further, the inner tube 12 is provided on the outer surface of the distal end of the center tube 11.
A conical surface 11a corresponding to the conical surface 12a is provided.
The direction of ejection of the fuel gas ejected from 8 is formed so as to form a focal point F1 on the axis C of the central tube 11.

The distal end of the outer tube 13 projects further forward than the distal end of the inner tube 12, and the outer surface of the distal end of the inner tube 12 and the inner surface of the outer tube 13 have the same conical surface as the fuel gas jet port 18. 12b, 13a are provided, and both conical surfaces 12b,
By 13a, the ejection direction of the secondary oxygen ejected from the secondary oxygen ejection port 19 is formed so as to form the focal point F2 on the axis C of the central tube 11.

That is, from the nozzle portion of the oxygen burner, the primary oxygen is linearly fed from the primary oxygen outlet 17 along the axis C of the central pipe 11, and the fuel gas is directed from the fuel gas outlet 18 toward the focal point F1. Secondary oxygen is ejected from the secondary oxygen outlet 19 so as to converge toward the focal point F2 so as to converge.

At this time, the dimensions of each part vary depending on conditions such as the amount of combustion of the oxygen burner, the type of fuel, the flow rates of primary and secondary oxygen, and the like. The angle α of the conical surface 11a with respect to C,
The angle β of the conical surface 12a, the angle γ of the conical surface 12b, and the angle δ of the conical surface 13a are each preferably 45 degrees or less. If these angles are set to more than 45, the rate at which the fuel gas ejected from the fuel gas ejection port 18 burns in the nozzle increases, so that the tip portions of the center pipe 11 and the inner pipe 12 are heated to a high temperature. This may cause damage to the nozzle.

Further, in the angles α and β of the conical surfaces 11 a and 12 a forming the fuel gas injection port 18, it is preferable that the angle β is equal to or larger than the angle α. Conical surfaces 12b, 13 forming 19
In the angle γ and the angle δ of a, it is preferable that the angle δ is equal to or larger than the angle γ. This allows
The fuel gas and the secondary oxygen can be ejected toward the focal points F1 and F2 without excessively diffusing.

Further, the distance L1 between the tip of the center pipe 11 and the tip of the inner pipe 12 is closely related to the diameter D1 of the fuel gas outlet 18, and L1 / D1 is in the range of 0.3 to 0.5. It is preferable to set so that L1 / D1 is 0.3
If it is less than 1, the mixing of the fuel gas and the primary oxygen becomes insufficient, and a part of the flame may become a bright flame at the burner outlet. Become. When L1 / D1 exceeds 0.5,
The rate at which fuel gas ejected from the fuel gas ejection port 18 burns in the nozzle increases, and the distal end portions of the center tube 11 and the inner tube 12 are heated, which may cause damage to the nozzle portion.

Similarly, the distance L2 between the distal end of the inner tube 12 and the distal end of the outer tube 13 is closely related to the diameter D2 of the secondary oxygen outlet 19, and L2 / D2 is 0.3 to 1.0. It is preferable to set so as to fall within the range. When L2 / D2 is less than 0.3, the mixing of the fuel gas and the secondary oxygen becomes insufficient, and it may be difficult to form a low-luminance flame or a bright flame. When L2 / D2 exceeds 1.0,
Because the rate at which fuel gas burns in the nozzle increases,
The tip portions of the inner tube 12 and the outer tube 13 may be heated to cause damage to the nozzle portion.

Further, the flow rate of the primary oxygen at the primary oxygen jet port 17 is 50 to 50 ° C. in terms of 0 ° C. and 1 atm.
It is desirable to set the flow rate to be in the range of 340 m / s and to set the flow rate higher than the flow velocity of the fuel gas ejected from the fuel gas ejection port 18. This flow rate is 50m /
If it is less than s, the force accompanying the fuel gas from the fuel gas ejection port 18 becomes weak, and the mixing state with the fuel becomes insufficient,
The formation of low intensity flames can be difficult. When the flow rate of the primary oxygen exceeds 340 m / s, the pressure loss for ejecting the primary oxygen increases, and it becomes difficult to supply sufficient oxygen to form a low-luminance flame or a bright flame. Sometimes. Further, if the flow rate of the primary oxygen is slower than the flow rate of the fuel gas, the effect of the primary gas accompanying the fuel gas may be lost, making it difficult to form a low-luminance flame.

By forming in this manner, the inner pipe 12
A primary mixing chamber 20 is formed on the inner peripheral side of the protruding portion, and the primary mixing chamber 20 mixes the primary oxygen ejected from the primary oxygen ejection port 17 with the fuel gas ejected from the fuel gas ejection port 18 toward the focal point F1. Mixing can be promoted and soot generation can be suppressed. Furthermore, on the inner peripheral side of the protruding portion of the outer tube 13,
A secondary mixing chamber 21 is formed, and the secondary mixing chamber 21
It is possible to promote the mixing of the secondary oxygen ejected from the secondary oxygen ejection port 19 toward the focal point F2 and the fuel oxygen mixed stream ejected from the primary mixing chamber 20, and it is difficult for the circulation flow to be generated in the nozzle portion. Therefore, generation of carbon can be suppressed. In addition, since fuel gas and secondary oxygen are ejected so as to converge toward the jet of primary oxygen,
The flame length can be lengthened by setting the flow rate of primary oxygen to be high. This makes it possible to obtain a low-luminance flame or a non-luminous flame in which no soot is generated, to obtain a long flame length, and to prevent carbon from adhering to the nozzle portion.

Although the flow rate ratio between the primary oxygen and the secondary oxygen is arbitrary, it is usually preferable that the primary oxygen is about 10 to 50% of the total oxygen amount. If the primary oxygen is too large, the fuel gas burns at a high rate in the vicinity of the primary oxygen outlet 17, so that the center tube 11 and the inner tube 12 are heated, which may cause damage to the nozzle. Conversely, if the amount of secondary oxygen is too large, there is a disadvantage that it becomes difficult to mix the central portion of the fuel flow with the oxygen sufficiently, so that it is difficult to form a bright flame or a low-luminance flame.

Further, the flow rate of the secondary oxygen at the secondary oxygen outlet 19 is suitably in the range of 20 to 50 m / s, and if it is too slow, the propulsive force of the flame is lost, causing problems such as winding. If the speed is too high, combustion in the vicinity of the secondary oxygen outlet 19 is promoted, and there is a disadvantage that the nozzle outlet is heated.

The purity of oxygen is arbitrary, and any oxygen-containing gas can be used. However, it is preferable to use pure oxygen or an oxygen-enriched gas having an oxygen concentration of 90% or more. As the fuel, a gaseous fuel such as natural gas, LPG, butane gas or the like can be used.

[0024]

As described above, according to the oxygen burner of the present invention, fuel gas and oxygen can be efficiently mixed and burned. And a long flame length can be obtained.
Further, it is possible to prevent carbon from adhering to the nozzle portion. Therefore, the object to be heated can be heated in a wide range by radiant heat from the flame without directly blowing the flame to the object to be heated. As the best.

[Brief description of the drawings]

FIG. 1 is a sectional side view showing one embodiment of an oxygen burner according to the present invention.

FIG. 2 is a cross-sectional side view of a nozzle unit.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

[Explanation of symbols]

11: central pipe, 12: inner pipe, 13: outer pipe, 14: primary oxygen flow path, 15: fuel gas flow path, 16: secondary oxygen flow path, 1
7: primary oxygen jet, 18: fuel gas jet, 19: secondary oxygen jet

Claims (2)

[Claims] A primary oxygen flow path is provided inside a central pipe, a fuel gas flow path is provided between the central pipe and an outer pipe outside the central pipe, and a secondary oxygen flow path is provided between the inner pipe and an outer pipe outside the central pipe. An oxygen burner having a triple pipe structure in which oxygen channels are formed, wherein the tip of the inner pipe projects forward from the tip of the center pipe, and is formed between the outer circumference of the center pipe tip and the inner circumference of the inner pipe. The direction in which fuel gas is ejected from the fuel gas ejection port is formed so as to be focused on the axis of the central pipe, and the tip of the outer pipe projects forward from the tip of the inner pipe. An oxygen burner, characterized in that a direction in which secondary oxygen is ejected from a secondary oxygen outlet formed between an outer periphery and an inner periphery of an outer tube is focused on an axis of the central tube. 2. The flow rate of primary oxygen spouted from a primary oxygen outlet at the end of the primary oxygen flow path is 0 ° C. and 1 atm.
2. The oxygen burner according to claim 1, wherein the oxygen burner is set in a range of 0 to 340 m / s and at a speed higher than a flow rate of the fuel gas ejected from the fuel gas ejection port.