JP6043393B2 - Burner flame formation method - Google Patents

Description

  The present invention relates to a flame forming method for a burner used in a heating furnace or a firing furnace used for manufacturing iron, non-ferrous metal, ceramics and the like.

  Conventionally, an air burner is used in a heating furnace used for manufacturing iron, non-ferrous metal, ceramics and the like. Further, a heat exchanger is provided at the outlet of the heating furnace, and the air is preheated so that the temperature of the air used for the air burner becomes a temperature in the range of 200 to 500 ° C.

As a combustion method for improving the thermal efficiency of a burner, there is an oxygen-enriched combustion method in which oxygen is added to combustion air. In the oxygen-enriched combustion method, by increasing the oxygen concentration, the temperature and brightness of the flame are improved and the radiant heat transfer efficiency is improved, so that the thermal efficiency of the burner can be improved.
As a burner using such an oxygen-enriched combustion method, for example, there is an oxygen-enriched combustion burner disclosed in Patent Document 1.

However, in the conventional oxygen-enriched combustion burner, as compared with the air combustion method, the flame temperature rises, the amount of the NO _X to be generated is a problem that increases. In particular, when preheating the combustion air in the heating furnace, the amount of the NO _X generated is increased extremely.
Moreover, since a local high temperature part will be formed in a flame, it was difficult to make the flame temperature uniform.

On the other hand, Patent Document 2 discloses a low NO _X burner. Specifically, in Patent Document 2, the exhaust gas in the furnace is attracted by providing a plurality of main air outlets at a distance from the fuel nozzle around the fuel nozzle provided at the center of the burner tile. In the self-exhaust gas recirculation type low NO _X burner, a plurality of auxiliary air nozzles are provided in the vicinity of the fuel nozzles in the vicinity of the fuel nozzles, and 0.1 to 5.0 kg / cm ² from the auxiliary air nozzles. A low NO _X burner is disclosed which is made by ejecting high pressure air.

  Patent Document 2 discloses a high oxygen concentration around a flame (primary flame) formed by ejecting fuel gas supplied from the center of a burner and ejecting auxiliary air from the outside of the fuel gas. It is disclosed that main air is supplied.

JP-A-10-169929 JP 11-173506 A

However, in the low NO _X burner disclosed in Patent Document 2, main air having a high oxygen concentration is supplied around the flame formed by the fuel gas supplied from the center and the auxiliary air. the temperature of the part is increased, the amount of the NO _X is disadvantageously increased.

The present invention has been made in view of the above circumstances, when oxygen-enriched combustion, and the flame at a uniform temperature, providing a flame formation method possible burners to suppress the generation of the NO _X This is the issue.

In order to solve the above-described problem , according to the first aspect of the present invention, a burner body extending in a predetermined direction and a primary oxidant that is disposed at the center of the tip of the burner body and ejects a primary oxidant. A jet port, a fuel gas jet port for jetting fuel gas disposed at the tip of the burner body located outside the primary oxidant jet port, an outer side of the burner body, A plurality of secondary oxidant jets that are disposed rotationally symmetrically with respect to the central axis, and jet the secondary oxidant, and are provided between the plurality of secondary oxidant jets and the fuel gas jet; A burner flame forming method using a burner having a tertiary oxidant jet outlet for jetting a tertiary oxidant as a swirling flow, wherein the primary oxidant is in the same direction as the extending direction of the burner body. And ejecting the fuel gas and the bar The tertiary oxidant is ejected as a swirling flow in the same direction as the main body extending direction, the primary oxidant is ejected at a speed higher than the fuel gas ejection speed, and is separated from the central axis of the burner body. There is provided a flame forming method for a burner, characterized in that a flame is formed by ejecting the secondary oxidant in a direction to perform.

According to the invention of claim 2 , the primary oxidant ejection speed is in the range of 100 m / s to 300 m / s, and the fuel gas ejection speed is in the range of 50 m / s to 150 m / s. flame formation method of claim 1 Symbol mounting of the burner, characterized in that it is provided.

According to a third aspect of the present invention, the burner has a combustion chamber having an expansion angle of 0 ° or more and 30 ° or less at the tip of the burner body, and the primary oxidant and the fuel 3. A burner flame forming method according to claim 1, wherein the gas is ejected into the combustion chamber.

According to a fourth aspect of the present invention, the angle formed by the central axis of the burner body and the ejection direction of the secondary oxidant is 0 ° or more and 30 ° or less. 3. A method for forming a flame of a burner according to any one of 3 is provided.

According to the fifth aspect of the present invention, when the amount of oxygen necessary for complete combustion of the fuel gas supplied to the fuel gas outlet is 100%, the primary oxidant outlet is of claims 1 to 4, wherein the flame forming method of the burner according to any one is provided that the amount of oxygen contained in the primary oxidizing agent supplied is 5% to 30% .

According to the sixth aspect of the invention, the flow rate B of the secondary oxidant supplied to the secondary oxidant jet and the flow rate C of the tertiary oxidant supplied to the tertiary oxidant jet. Then, the following formula (1) is established, and the burner flame forming method according to any one of claims 1 to 5 is provided.
0 ≦ C / (B + C) ≦ 0.4 (1)

Further, the invention according to claim 7, wherein is 1-order concentration of oxygen contained in the oxidizing agent is 80% or more, of claims 1 to 6, wherein the secondary oxidant is air A burner flame forming method according to any one of the preceding claims is provided.

According to the present invention, at the time of oxygen-enriched combustion, the flame can be brought to a uniform temperature and the production of NO _X can be suppressed.

It is sectional drawing which shows schematic structure of the burner used when implementing the flame formation method of the burner of the 1st Embodiment of this invention. It is the front view which looked at the burner fixed to the furnace wall shown in FIG. It is sectional drawing which shows schematic structure of the burner used when implementing the flame formation method of the burner of the 2nd Embodiment of this invention. It is the front view which looked at the burner fixed to the furnace wall shown in FIG. It is sectional drawing which shows schematic structure of the burner used by the comparative example. It is a graph showing the relationship between the C / obtained in Experimental Example 2 (B + C) and NO _X concentration _(O 2 11% conversion). It is a graph which shows the relationship between the distance from the front surface of a front member main body, and the temperature of the inner wall of a test furnace. Is a graph showing the relationship between the blowing speed and the NO _X concentration _(O 2 11% conversion) and CO concentration of the primary oxidant. Is a graph showing the relationship between the blowing speed and the NO _X concentration _(O 2 11% conversion) and CO concentration of the fuel gas. The relationship between the flow rate ratio of the primary oxidant to the flow rate of the entire oxidant, the NO _X concentration (O ₂ 11% conversion), and the CO concentration is shown.

  Embodiments to which the present invention is applied will be described below in detail with reference to the drawings. The drawings used in the following description are for explaining the configuration of the embodiment of the present invention, and the size, thickness, dimensions, etc. of each part shown in the drawings may be different from the actual dimensional relationship of the burner. is there.

(First embodiment)
FIG. 1 is a cross-sectional view showing a schematic configuration of a burner used when performing the flame forming method of the burner according to the first embodiment of the present invention. In FIG. 1, for convenience of explanation, a heating furnace 11 (including a furnace wall 12) that is not a component of the burner 10 is illustrated. That is, in FIG. 1, the case where the burner 10 is provided in the heating furnace 11 is illustrated as an example.
In FIG. 1, E is a central axis of the burner body 17 (hereinafter referred to as “central axis E”), X is an extending direction of the central axis E (hereinafter referred to as “direction X”), and F is a jet of secondary oxidant. A direction (hereinafter referred to as “direction F”), G is a direction of the direction X, and indicates the ejection direction of the primary oxidant and the fuel gas (hereinafter referred to as “direction G”).
FIG. 2 is a front view of the burner fixed to the furnace wall shown in FIG. 2, the same components as those in the structure shown in FIG.

First, with reference to FIG. 1 and FIG. 2, the structure of the burner 10 used when implementing the flame formation method of the burner of 1st Embodiment is demonstrated.
The burner 10 includes an air box 15 and a burner body 17. The wind box 15 includes a cylindrical member 21, a guide member 22, a back member 23, a front member 25, and a flange portion 26.

  The tubular member 21 has a tubular member main body 28 and a secondary oxidant introduction port 29. The cylindrical member main body 28 is disposed so as to extend in the direction X. The cylindrical member body 28 has a space 31 into which a secondary oxidant is introduced. The shape of the cylindrical member main body 28 can be a cylindrical shape, for example.

The secondary oxidant introduction port 29 is provided so as to penetrate the upper part of the cylindrical member main body 28. The secondary oxidant inlet 29 is connected to a secondary oxidant supply source (not shown) via a secondary oxidant supply line (not shown). The secondary oxidant inlet 29 is an inlet for introducing the secondary oxidant into the space 31.
As the secondary oxidant supplied from a secondary oxidant supply source (not shown), for example, any one of oxygen, oxygen-enriched air, and air can be used.
The secondary oxidant inlet 29 and the space 31 described above function as a path for supplying the secondary oxidant.

The guide member 22 is a member that is considerably thinner than the cylindrical member 21, and is disposed so as to cover the outer surface excluding the front end surface of the cylindrical member 21. The guide member 22 is provided so as to protrude from the tip of the cylindrical member 21.
A portion of the guide member 22 that protrudes from the tip of the cylindrical member 21 is disposed in a through portion 12A formed in the furnace wall 12 and is in contact with the furnace wall 12 that defines the through portion 12A.

The back member 23 includes a first portion 23-1, a second portion 23-2, and a through hole 23A.
The first portion 23-1 is accommodated in the rear end of the space 31 and has an outer diameter substantially equal to the inner diameter of the space 31. For example, when the shape of the space 31 is a cylindrical shape, the shape of the first portion 23-1 can also be a cylindrical shape.

The second portion 23-2 is configured integrally with the first portion 23-1 and is disposed outside the cylindrical member 21. The second portion 23-2 is a member that is considerably thinner than the first portion 23-1.
The second portion 23-2 is a member whose diameter is larger than that of the first portion 23-1, and is fixed to the rear end of the tubular member main body 28 by a bolt 33. Thereby, the rear end side of the wind box 15 is airtight.

The through hole 23A is provided so as to penetrate the center of the first and second portions 23-1 and 23-2 in the direction X. The diameter of the through hole 23 </ b> A is configured to be substantially equal to the outer diameter of the burner body 17. The through hole 23 </ b> A is a hole for inserting the rear end side of the burner body 17.
The back member 23 configured as described above has a function of supporting the rear end side of the burner body 17.

The front member 25 includes a front member main body 34, an insertion hole 35, a combustion chamber 37, and a plurality of secondary oxidant ejection ports 38.
The front member body 34 is a plate-shaped member, and has a flat front surface 34a and a back surface 34b. The front member main body 34 is disposed such that the back surface 34b is in contact with the front end surface 28A of the cylindrical member 28.
A part of the front member body 34 is disposed in the guide member 22, and the remaining part projects from the guide member 22. The front member main body 34 is accommodated in a through portion 12A that penetrates the furnace wall 12. As a result, the front surface 34 a of the front member body 34 is exposed to the atmosphere in the heating furnace 11.

The insertion hole 35 is a hole that penetrates the central portion of the front member body 34 from the back surface 34b side. The insertion hole 35 is a portion into which the tip of the burner body 17 is inserted.
The diameter of the insertion hole 35 is configured to be substantially equal to the outer diameter of the tip of the burner body 17.

The combustion chamber 37 is provided in the front member main body 34 located between the insertion hole 35 and the front surface 34 a of the front member main body 34. The bottom surface 37 a of the combustion chamber 37 that exposes the tip of the burner body 17 is larger than the inner diameter of the insertion hole 35.
The combustion chamber 37 is provided at the tip of the burner body 17 and has an expansion angle of 0 ° to 30 °.
If the spread angle is smaller than 0 °, the gas blowing speed from the combustion chamber 37 is increased, and it may be difficult to form a stable flame. On the other hand, if the spread angle is greater than 30 °, the amount of radiant heat transferred to the tip of the burner body 17 and the combustion chamber 37 by the flame increases, and the tip of the burner body 17 and the combustion chamber 37 may be damaged or deteriorated in durability. There is.
Therefore, by setting the spread angle to 0 ° or more and 30 ° or less, flame stability can be maintained, damage to the burner body 17 can be suppressed, and durability of the burner body 17 can be improved.
As the shape of the combustion chamber 37, for example, a columnar shape or a truncated cone shape can be used.
A primary oxidant and fuel gas are ejected from the tip of the burner body 17 into the combustion chamber 37 having the above-described configuration.

The plurality of secondary oxidant jets 38 are jets that eject the secondary oxidant. The plurality of secondary oxidant jets 38 are provided so as to penetrate the burner body 17 and the front member body 34 located outside the combustion chamber 37, and are connected to the space 31.
The plurality of secondary oxidant jets 38 are arranged rotationally symmetrically with respect to the central axis E of the burner body 17. The plurality of secondary oxidant jets 38 extend in a direction away from the central axis E of the burner body 17. For this reason, the secondary oxidant ejected from the plurality of secondary oxidant ejection ports 38 is ejected in the direction F away from the central axis E.

By providing the plurality of secondary oxidant jets 38 configured as described above, the secondary oxidant ejected from the plurality of secondary oxidant jets 38 is diluted with the gas in the heating furnace 11. The burner body 17 is taken into the primary flame.
Accordingly, the temperature of the flame 40 it is possible to suppress the high temperatures locally, it is possible to suppress the generation of NO _X.
In the first embodiment, the “primary flame” refers to a reduced flame formed only from the primary oxidant and fuel gas supplied from the burner body 17, and the “flame 40” A flame formed by supplying a secondary oxidant to a primary flame.

The angle formed by the central axis E of the burner body 17 and the direction F (hereinafter referred to as “angle θ1”) is preferably, for example, greater than 0 ° and 30 ° or less.
If the angle θ1 is 0 ° or less, it is difficult to eject the secondary oxidant in a direction away from the central axis E of the burner body 17. Thus, without secondary oxidant is sufficiently diluted with a gas in the heating furnace 11, since it is incorporated into the flame 40, it becomes difficult to suppress the generation of NO _X.

On the other hand, if the angle θ1 is larger than 30 °, the secondary oxidant is slowly involved in the primary flame, so that the flame 40 may become extremely long or unburned.
Therefore, by making the angle θ1 larger than 0 ° and not more than 30 °, the generation of NO _X is suppressed while suppressing the flame 40 from becoming extremely long or the occurrence of unburned. be able to.

  In FIG. 2, as an example of a plurality of secondary oxidant jets 38, a case where four circular jets are provided has been described as an example. The size can be appropriately determined in consideration of the ejection speed of the secondary oxidant, and is not limited to the secondary oxidant ejection port 38 shown in FIG.

  The flange portion 26 is provided outside the guide member 21 located in the vicinity of the boundary between the tubular member 21 and the front member 25. The flange portion 26 is fixed to the furnace wall 12 located on the outer surface 12 b side by a bolt 41.

The burner body 17 has a tip portion inserted into the insertion hole 35 and a part on the rear end side accommodated in the through hole 23A. Thereby, the burner body 17 is fixed in the wind box 15.
The burner body 17 includes a first annular member 43, a primary oxidant supply path 45, a primary oxidant outlet 46, a second annular member 48, a fuel gas supply path 49, and a fuel gas outlet. 51 and a fuel gas inlet 53.

The first annular member 43 is a cylindrical member extending in the direction X. The rear end of the first annular member 43 is connected to a primary oxidant supply source (not shown) via a primary oxidant supply line (not shown).
As a primary oxidant supplied from a primary oxidant supply source (not shown), for example, any one of oxygen, oxygen-enriched air, and air can be used.
The primary oxidant supply path 45 is a space formed in the first annular member 43 and extending in the direction X. The primary oxidant supply path 45 supplies the primary oxidant supplied from a primary oxidant supply source (not shown) to the primary oxidant jet 46 located on the tip side of the burner body 17.

  The primary oxidant jet 46 is disposed at the tip of the first annular member 43. The primary oxidant ejection port 46 is exposed to the combustion chamber 37, and ejects the primary oxidant in the direction G with respect to the combustion chamber 37. The shape of the primary oxidant jet 46 can be, for example, circular.

The second annular member 48 is disposed outside the first annular member 43 in a state where a gap is interposed between the second annular member 48 and the first annular member 43. The second annular member 48 is a cylindrical member. The first and second annular members 43 and 48 are arranged concentrically with respect to the central axis E of the burner body 17.
The fuel gas supply path 49 is a cylindrical space formed between the first annular member 43 and the second annular member 48. The fuel gas supply path 49 has a function of supplying fuel gas to the fuel gas outlet 51.

The fuel gas outlet 51 is defined by the tips of the first and second annular members 43 and 48.
The fuel gas ejection port 51 is exposed to the combustion chamber 37 and ejects fuel gas in the direction G with respect to the combustion chamber 37. The shape of the fuel gas ejection port 51 can be, for example, a ring shape.
The fuel gas inlet 53 is provided in the second annular member 48. The fuel gas inlet 53 is connected to a fuel gas supply source (not shown) through a fuel gas supply line (not shown).
For example, LNG (Liquid Natural Gas) can be used as the fuel gas supplied from a fuel gas supply source (not shown).

The primary oxidant and the fuel gas are ejected into the combustion chamber 37 through the tip of the burner body 17 having the above-described configuration, thereby forming a primary flame that is a reducing flame.
Then, the secondary oxidant is ejected in a direction away from the central axis E of the burner body 17, and the secondary oxidant is diluted with the gas in the heating furnace 11 and is taken into the primary flame, whereby the temperature is increased. is uniform, flame 40 produced is reduced of the NO _X is formed.

Next, with reference to FIG.1 and FIG.2, the flame formation method of the burner of 1st Embodiment using the burner 10 is demonstrated.
In the flame forming method of the burner according to the first embodiment, the primary oxidant is ejected from the center of the burner body 17 and the fuel gas is ejected from the outside of the primary oxidant to eject the primary oxidant. The flame 40 is formed by jetting the secondary oxidant in a direction away from the central axis E of the burner body 17 from the outside of the fuel gas at a speed higher than the jet speed of the fuel gas.

In this way, the primary oxidant and the fuel gas are ejected from the burner body 17 in the same direction, and the primary oxidant is ejected at a speed higher than the fuel gas ejection speed, so that an overall uniform temperature is obtained. A primary flame, which is the reduced fire, can be formed.
Then, the secondary oxidant diluted with the gas in the heating furnace 11 and the primary flame are ejected from the outside of the fuel gas in a direction away from the central axis E of the burner body 17. It becomes possible to react gradually. This allows the undiluted secondary oxidant to react with the primary flame at an early stage.
Accordingly, at the time of oxygen-enriched combustion, since it is possible to suppress the local high-temperature portion is formed in the flame 40, it is possible to suppress the generation of NO _X.

  In the flame forming method of the burner, for example, the ejection speed of the primary oxidant may be in the range of 100 m / s to 300 m / s, and the fuel gas ejection speed may be in the range of 50 m / s to 150 m / s. .

Thus, it becomes possible to form the flame 40 spaced apart from the tip of the burner body 17 by setting the jet velocity of the primary oxidant within the range of the jet velocity under the condition where the jet velocity of the fuel is higher than the jet velocity of the fuel. It is possible to suppress the formation of a high temperature portion in the vicinity of the burner body 17.
In addition, since the primary oxidant can sufficiently entrain the combustion gas during oxygen-enriched combustion, the oxygen concentration in the flame 40 is reduced, and the formation of local high-temperature portions can be suppressed. , NO _X generation can be suppressed.

  In the flame forming method of the burner, for example, the primary oxidant and the fuel gas may be jetted into the combustion chamber 37 provided at the tip of the burner body 17.

  In this way, the primary oxidant and the fuel gas are ejected into the combustion chamber 37, so that the combustion chamber 37 maintains a high temperature when the flame 40 is formed, so that the flame 40 separated from the tip of the burner body 17 is formed. Even in this case, the flame 40 can be formed stably.

In the flame formation method of the burner, an angle θ1 formed by the central axis E of the burner body 17 and the secondary oxidant ejection direction (that is, the direction F) may be, for example, 0 ° or more and 30 ° or less.
If the angle θ1 is smaller than 0 °, it may be difficult to eject the secondary oxidant in a direction away from the central axis E of the burner body 17. In this case, prior to sufficiently dilute the secondary oxidant gas in the heating furnace 11, since the secondary oxidant into the flame 40 is captured, it may be difficult to suppress the generation of NO _X.

On the other hand, if the angle θ1 is larger than 30 °, the secondary oxidant is slowly involved in the primary flame, so that the flame 40 may become extremely long or unburned.
Therefore, by setting the angle θ1 to 0 ° or more and 30 ° or less, it is possible to suppress the generation of NO _x while suppressing the flame 40 from becoming extremely long or causing unburnt.

  In the flame forming method of the burner, when the amount of oxygen necessary for completely burning the fuel gas supplied to the fuel gas outlet 51 is 100%, the primary oxidant supplied to the primary oxidant outlet 46 The amount of oxygen contained in may be, for example, 5% or more and 30% or less.

If the amount of oxygen contained in the primary oxidizer is less than 5%, the flame length of the primary flame may become too long or unburned may occur. On the other hand, when the amount of oxygen contained in the primary oxidant is greater than 30%, the reduction of the primary flame is weakened, there is a possibility that generation of the NO _X increases.
Therefore, by controlling the amount of oxygen contained in the primary oxidizer to be 5% or more and 30% or less, the flame length of the primary flame is prevented from becoming too long or unburned, and NO. Generation of _X can be suppressed.

  In the flame forming method of the burner, for example, the oxygen concentration contained in the primary oxidant may be 80% or more, and air may be used as the secondary oxidant.

  Thus, since the oxygen concentration contained in the primary oxidant is 80% or more and air is used as the secondary oxidant, only one oxygen supply system needs to be prepared, thereby simplifying the equipment. And the equipment cost can be reduced.

  In the flame forming method of the burner, for example, the temperature of the secondary oxidant supplied to the secondary oxidant jet 38 may be 600 ° C. or less.

When the temperature of the secondary oxidant supplied to the secondary oxidant outlet 38 is higher than 600 ° C., there is a possibility that the production of NOx increases.
Therefore, since the temperature of the flame 40 can be increased by setting the temperature of the secondary oxidant supplied to the secondary oxidant outlet 38 to 600 ° C. or less, the heat transfer efficiency to the object to be heated is increased. Can be improved. Further, in the above temperature range, combustion with suppressed generation of NO _X can be performed.

According to the burner flame forming method of the first embodiment, fuel gas is ejected from the center of the burner body 17 in the direction G from the outside of the primary oxidant and the primary oxidant. By making the jetting speed of the oxidant faster than the jetting speed of the fuel gas, it becomes possible to form a primary flame that is a reducing fire having a uniform temperature as a whole.
Further, the secondary oxidant diluted with the gas in the heating furnace 11 and the primary flame are ejected from the outside of the fuel gas in a direction away from the central axis E of the burner body 17. It becomes possible to react gradually.
Accordingly, at the time of oxygen-enriched combustion, since it is possible to suppress the local high-temperature portion is formed in the flame 40, it is possible to suppress the generation of NO _X.

(Second Embodiment)
FIG. 3 is a cross-sectional view showing a schematic configuration of a burner used when performing the flame forming method of the burner according to the second embodiment of the present invention.
In FIG. 3, for convenience of explanation, the heating furnace 11 (including the furnace wall 12) that is not a component of the burner 60 is illustrated. That is, in FIG. 3, the case where the burner 60 is provided in the heating furnace 11 is illustrated as an example.
3, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.
4 is a front view of the burner fixed to the furnace wall shown in FIG. 4, the same components as those shown in FIGS. 1 to 3 are denoted by the same reference numerals.

First, with reference to FIG. 3 and FIG. 4, the structure of the burner 60 used when implementing the flame forming method of the burner of 2nd Embodiment is demonstrated.
The burner 60 has a burner main body 61 instead of the burner main body 17 constituting the burner 10 described in the first embodiment, and the arrangement of the plurality of secondary oxidant jets 38 from the cross arrangement to the X-shape. The configuration is the same as that of the burner 10 except that the arrangement is changed.

  The burner main body 61 has a configuration of the burner main body 17 described in the first embodiment, a third annular member 62, a tertiary oxidant supply path 63, a tertiary oxidant introduction port 65, and a swivel. The burner body 17 is configured in the same manner as the burner body 17 except that the blade 68 and the tertiary oxidant jet port 69 are provided.

The third annular member 62 is a cylindrical member disposed outside the second annular member 48. The first to third annular members 43, 48 and 62 are arranged concentrically around the central axis E of the burner body 61.
The third annular member 62 is configured such that the length in the direction X is shorter than that of the second annular member 48. The third annular member 62 exposes the fuel gas inlet 53.

The tertiary oxidant supply path 63 is a cylindrical space formed between the second annular member 48 and the third annular member 62. The tertiary oxidant supply path 63 has a function of supplying the tertiary oxidant to the tertiary oxidant jet 69.
The tertiary oxidant inlet 65 is provided in the third annular member 62. The tertiary oxidant inlet 65 is connected to a tertiary oxidant supply source (not shown) via a tertiary oxidant supply line (not shown).
As a tertiary oxidant supplied from a tertiary oxidant supply source (not shown), for example, any one of oxygen, oxygen-enriched air, and air can be used.

  The swirl vane 68 is provided in the tertiary oxidant supply path 63 located between the insertion hole 35 and the through hole 23A and on the insertion hole 35 side. The swirl vanes 68 have a function of turning a tertiary oxidant supplied from a tertiary oxidant supply source (not shown) into a swirl flow.

The tertiary oxidant jet 69 is defined by the tips of the second and third annular members 48 and 62.
The tertiary oxidant jet port 69 is exposed to the combustion chamber 37, and ejects the tertiary oxidant that is swirled in the direction G to the combustion chamber 37. The shape of the tertiary oxidant jet 69 can be, for example, a ring shape.

Next, with reference to FIG.3 and FIG.4, the flame formation method of the burner of 1st Embodiment using the burner 10 is demonstrated.
In the flame forming method of the burner according to the second embodiment, a tertiary oxidant jet provided between the plurality of secondary oxidant jets 38 and the fuel gas jet 51 when the flame 70 is formed. The method can be performed by the same method as the flame forming method of the burner according to the first embodiment except that the tertiary oxidant is jetted from 69 as a swirling flow.
As described above, the third oxidant is jetted out as a swirling flow from the third oxidant jet 69 provided between the plurality of secondary oxidant jets 38 and the fuel gas jet 51, thereby providing a flame holding effect. Thus, a more stable flame 70 can be formed.

Further, in the flame forming method of the burner according to the second embodiment, the flow rate B of the secondary oxidant supplied to the secondary oxidant jet 38 and the tertiary oxidant supplied to the tertiary oxidant jet 69. When the flow rate is C, for example, the flow rates B and C of the secondary oxidizer and the tertiary oxidizer may be set so that the following formula (2) is satisfied.
0 ≦ C / (B + C) ≦ 0.4 (2)

In this way, the flame length of the flame 70 can be controlled by adjusting the flow rate B of the secondary oxidant and the flow rate C of the tertiary oxidant so that the above expression (2) is satisfied.
Further, when the ratio of the tertiary oxidizer is increased, the mixing of the fuel gas and the tertiary oxidizer is accelerated, so that the flame length of the flame 70 can be shortened.

According to the burner flame forming method of the second embodiment, a tertiary oxidant is generated from a tertiary oxidant jet 69 provided between the plurality of secondary oxidant jets 38 and the fuel gas jet 51. Is ejected as a swirling flow, and a stable flame 70 can be formed by the flame holding effect.
Further, the burner flame forming method of the second embodiment can achieve the same effects as the burner flame forming method of the first embodiment.

  In addition, the flame 70 in 2nd Embodiment is secondary oxidation to the primary flame (reduction flame) formed with the primary oxidizer supplied from the burner main body 61, the tertiary oxidizer, and fuel gas. This refers to the flame formed by supplying the agent.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and within the scope of the present invention described in the claims, Various modifications and changes are possible.

  Hereinafter, although an example and a comparative example are explained, the present invention is not limited to the following example.

(Experimental example 1)
In Experimental Example 1, the burner 10 shown in FIG. 1 is installed in a test furnace (not shown), the combustion tests of Examples 1 to 3 are performed under the conditions shown in Table 1, and the outlet of the test furnace (not shown) The NO _X concentration in the vicinity (converted to O ₂ 11%) was calculated.

As shown in Table 1, in Examples 1 to 3, the oxygen concentration contained in the oxidizer obtained by adding the primary oxidizer and the secondary oxidizer was 25%.
In Example 1, oxygen-enriched air having an oxygen concentration of 25% was used as the primary oxidant and the secondary oxidant. In Example 2, oxygen-enriched air having an oxygen concentration of 25% was used as the primary oxidant, and air having an oxygen concentration of 21% was used as the secondary oxidant.
In Example 3, air having an oxygen concentration of 21% was used as the primary oxidant, and oxygen-enriched air having an oxygen concentration of 25.2% was used as the secondary oxidant.

Next, a method for calculating the NO _X concentration (converted to O ₂ 11%) in Examples 1 to 3 will be described.
As the NO _X concentration in Examples 1 to 3, the NO _X concentration (ppm) in terms of O ₂ 11% conversion (oxygen concentration standard) was determined using the following formula (3).
NO _X concentration (ppm) = (21−converted O ₂ concentration) / (21−actual O ₂ concentration) × actual NO _X concentration (ppm) (3)

In the above formula (3), “actual O ₂ concentration” indicates a value obtained by measuring the O ₂ concentration in exhaust gas (value measured using VA-3000 manufactured by Horiba, Ltd.). “Actual NO _X concentration” indicates a value obtained by measuring the NO _X concentration in exhaust gas (a value measured by NOA-7000 manufactured by Shimadzu Corporation). “21” is a numerical value of the oxygen concentration in the air, and the unit indicates percent.
As for “converted O ₂ concentration”, in Examples 1 to 3, the converted O ₂ concentration is 11% based on calculating the NO _X concentration using the standard oxygen concentration correction in the air pollution prevention method or the like. Converted.

FIG. 5 is a cross-sectional view showing a schematic configuration of the burner used in the comparative example.
In Experimental Example 1, the burner 100 shown in FIG. 5 was installed in a test furnace (not shown), and a combustion test of a comparative example was performed.

Here, with reference to FIG. 5, the structure of the burner 100 used by the comparative example is demonstrated easily. The burner 100 is a burner disclosed in Patent Document 2.
The burner 100 includes an inner tube 101 to which fuel gas is supplied, a raw material gas outlet 102 provided at the distal end of the inner tube 101, an outer tube 104 that houses the inner tube 101, a distal end of the inner tube 101, and an outer tube. The auxiliary oxidant outlet 106, which is partitioned at the tip of 104, the main oxidant passage 108, the burner tile 109, and the main oxidant outlet 111 which is partitioned by the burner tile 109 and ejects the main oxidant. .

The burner 100 used in the comparative example is configured such that fuel gas is ejected from the center of the burner 100, auxiliary oxidant is ejected from the outside, and main oxidant is ejected from the outside of the auxiliary oxidant.
In the comparative example, a combustion test was performed using the conditions shown in Table 3, and the NO _X concentration (O ₂ 11% conversion) in the vicinity of the outlet of the test furnace (not shown) was calculated.

Referring to Table 3, the NO _X concentration of the comparative example was 320 ppm. On the other hand, the NO _X concentration in Examples 1 to 3 was 26 to 36.7 ppm, and it was confirmed that the NO _X concentration could be sufficiently reduced.

(Experimental example 2)
In Experimental Example 2, the burner 60 shown in FIG. 2 was installed in a test furnace (not shown), a burn test of the burner 60 was performed under the conditions shown in Table 4, and the test furnace ( The NO _X concentration (converted to O ₂ 11%) in the vicinity of the outlet (not shown) was calculated.
At this time, the value of (the flow rate C of the tertiary oxidant) / (the flow rate B of the secondary oxidant + the flow rate C of the tertiary oxidant) was changed within a range of 0 to 0.7. Hereinafter, (the flow rate C of the tertiary oxidant) / (the flow rate B of the secondary oxidant B + the flow rate C of the tertiary oxidant) is simply referred to as C / (B + C).

Figure 6 shows the relationship between the C / obtained in Experimental Example 2 (B + C) and NO _X concentration _(O 2 11% conversion). Figure 6 is a graph showing the relationship between the C / (B + C) and NO _X concentrations obtained in Experimental Example 2.
Referring to FIG. 6, as the value of C / (B + C) is increased, it was found that NO _X concentration increases. In addition, since the NO _x regulation value for a metal heating furnace with an exhaust gas amount of 100,000 m ³ / h or more is 100 ppm, in order to make the NO _x concentration 100 ppm or less, C / (B + C) It was found that the numerical value must be 0 or more and 0.4 or less.

In Experimental Example 2, the distance from the front surface 42a of the front member body 42 when C / (B + C) is 0, 0.2, 0.4, and 0.6 using the burner 60 shown in FIG. The relationship with the temperature of the inner wall was investigated. The result is shown in FIG. Moreover, the length of the flame at this time was observed visually.
FIG. 7 is a graph showing the relationship between the distance from the tip of the burner body and the temperature of the inner wall of the test furnace.

From the result of the length of the flame observed when obtaining the result shown in FIG. 7, when the ratio of the tertiary oxidizer is increased, the length of the flame is shortened and the position where the maximum temperature is reached approaches the burner body 61. I found out. It was also confirmed that the length of the flame could be adjusted by adjusting the ratio of the tertiary oxidant.
Furthermore, when C / (B + C) was increased to 0.6, the flame length tended to increase. This is considered to be because the state of the flame has changed.

(Experimental example 3)
In Experimental Example 3, the burner 10 shown in FIG. 1 used in Experimental Example 1 was used, and a combustion test was performed using the first condition shown in Table 5.
Then, the NO _X concentration (O ₂ 11% conversion) in the vicinity of the exit of the test furnace (not shown) is calculated by the same method as in Experimental Example 1, and the CO concentration in the vicinity of the exit of the test furnace (not shown). Was measured.
The CO concentration was measured using VA-3000 manufactured by Horiba.

FIG. 8 shows the results of investigating the relationship between the primary oxidant ejection speed, the NO _x concentration (O ₂ 11% conversion), and the CO concentration using the first condition.
FIG. 8 is a graph showing the relationship between the ejection speed of the primary oxidant, the NO _X concentration (O ₂ 11% conversion), and the CO concentration.

Referring to FIG. 8, the NO _X concentration tends to decrease as the primary oxidant ejection speed increases, and the CO concentration increases as the primary oxidant ejection speed increases. It turns out that there is a tendency.
From the results shown in FIG. 8, it was confirmed that the ejection speed of the primary oxidant is preferably in the range of 100 m / s to 300 m / s.

In Experimental Example 3, the burner 10 shown in FIG. 1 used in Experimental Example 1 was used, and a combustion test was performed using the second condition shown in Table 5.
Then, the NO _X concentration (O ₂ 11% conversion) in the vicinity of the exit of the test furnace (not shown) is calculated by the same method as in Experimental Example 1, and the CO concentration in the vicinity of the exit of the test furnace (not shown). Was measured. The CO concentration was measured by the method described above.
FIG. 9 shows the results of examining the relationship between the fuel gas ejection speed, the NO _X concentration (O ₂ 11% conversion), and the CO concentration using the second condition.
FIG. 9 is a graph showing the relationship between the fuel gas ejection speed, the NO _X concentration (converted to O ₂ 11%), and the CO concentration.

Referring to FIG. 9, the NO _X concentration tends to decrease as the fuel gas ejection speed increases, and the CO concentration tends to increase as the fuel gas ejection speed increases. I understood.
From the results shown in FIG. 9, it was confirmed that the fuel gas ejection speed is preferably within the range of 50 m / s to 150 m / s.

  From the results shown in FIG. 8 and FIG. 9, it is found that it is preferable to set the primary oxidant jet speed to 100 m / s to 300 m / s and the fuel gas jet speed to 50 m / s to 150 m / s. It was.

(Experimental example 4)
In Experimental Example 4, the burner 10 shown in FIG. 1 used in Experimental Example 1 was used, and a combustion test was performed using Conditions 1 to 6 shown in Table 6. Then, to calculate the NO _X concentration near the exit of the test furnace when changing the flow rate balance of the primary oxidizer and secondary oxidizer (not shown) (O 2 _11% conversion), the test furnace (shown The CO concentration in the vicinity of the outlet was measured. At this time, the length of the flame was also observed visually.
Further, calculation of the NO _X concentration _(O 2 11% conversion), and measurement of CO concentration, using the above-described method. These results are shown in FIG.

Figure 10 shows the relationship between the flow rate and the NO _X concentration _(O 2 11% conversion) and CO concentration of the primary oxidant to the flow rate of the whole oxidizing agent.
In addition, the flow rate ratio of the primary oxidant with respect to the flow rate of the entire oxidant means a ratio calculated from the following formula (4).
Primary oxidant flow rate ratio = (primary oxidant flow rate) / (primary oxidant flow rate and secondary oxidant flow rate) (4)

Referring to FIG. 10, the higher the flow rate of the primary oxidant, NO _X concentration is decreased, the length of the flame becomes longer, it was confirmed that the CO concentration becomes high.

  The present invention can be applied to a flame forming method for a burner used in a heating furnace or a firing furnace used for manufacturing iron, non-ferrous metal, ceramics, or the like.

  DESCRIPTION OF SYMBOLS 10,60 ... Burner, 11 ... Heating furnace, 12 ... Furnace wall, 12a ... Inner surface, 12b ... Outer surface, 12A ... Penetration part, 15 ... Wind box, 17, 61 ... Burner main body, 21 ... Cylindrical member, 22 ... Guide 23, ... Back member, 23A ... Through hole, 23-1 ... First part, 23-2 ... Second part, 25 ... Front member, 26 ... Flange, 28 ... Cylindrical member body, 28A ... Tip 29, secondary oxidant inlet, 31 ... space, 33, 41 ... bolt, 34 ... front member body, 34a, 42a ... front, 34b ... back, 35 ... insertion hole, 37 ... combustion chamber, 37a ... bottom 38 ... Secondary oxidant jet, 40, 70 ... Flame, 42 ... Front member body, 43 ... First annular member, 45 ... Primary oxidant supply path, 46 ... Primary oxidant jet, 48 ... Second annular member 49... Fuel gas supply path 51. Fuel gas outlet 53 Fuel gas inlet, 62 ... third annular member, 63 ... tertiary oxidant supply path, 65 ... tertiary oxidant inlet, 68 ... swirl vane, 69 ... tertiary oxidant jet E ... central axis, F , G ... direction

Claims (7)

A burner body extending in a predetermined direction, a primary oxidant jet port that is disposed at the center of the tip of the burner body, and jets a primary oxidant, and is located outside the primary oxidant jet port A fuel gas ejection port for ejecting fuel gas, disposed at the tip of the burner body, and provided on the outside of the burner body, and disposed rotationally symmetrically with respect to the central axis of the burner body, ejects a secondary oxidant. A plurality of secondary oxidant jets, and a tertiary oxidant jet provided between the plurality of secondary oxidant jets and the fuel gas jet and ejecting the tertiary oxidant as a swirling flow; A flame forming method for a burner using a burner having
  The primary oxidant and the fuel gas are ejected in the same direction as the extension direction of the burner body, and the tertiary oxidant is ejected as a swirl flow in the same direction as the extension direction of the burner body, A flame is formed by jetting the secondary oxidant in a direction away from the central axis of the burner body, with a jetting speed of the primary oxidant being faster than a jetting speed of the fuel gas. Burner flame formation method. The ejection speed of the primary oxidizing agent is not more than 100 m / s or more 300 meters / s, and of claim 1, wherein the ejection velocity of the fuel gas is in the range below 50 m / s or more 150 meters / s Burner flame formation method. The burner has a combustion chamber that is spread at the tip of the burner body and has an angle of 0 ° to 30 °,
The burner flame forming method according to claim 1 or 2 , wherein the primary oxidant and the fuel gas are jetted into the combustion chamber. A central axis and the angle which the injection direction is formed between the secondary oxidant of the burner body, 0 ° or 30 ° of the claims 1 to 3, characterized in that the following, according to any one of the burners Flame formation method. Oxygen contained in the primary oxidant supplied to the primary oxidant jet when the amount of oxygen necessary for complete combustion of the fuel gas supplied to the fuel gas jet is 100% The flame forming method for a burner according to any one of claims 1 to 4 , wherein the amount is 5% or more and 30% or less. When the flow rate B of the secondary oxidant supplied to the secondary oxidant jet port and the flow rate C of the tertiary oxidant supplied to the tertiary oxidant jet port are satisfied, the following formula (1) is established. The method for forming a flame of a burner according to any one of claims 1 to 5 , wherein:
0 ≦ C / (B + C) ≦ 0.4 (1) The oxygen concentration contained in the primary oxidant is 80% or more;
The flame forming method for a burner according to any one of claims 1 to 6 , wherein the secondary oxidant is air.

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