JP2004257673A - Combustion method using tubular flame burner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustion method for a tubular flame burner achieving super lower NOx and super lower SPM and energy saving during combustion with a tubular flame burner mounted in a furnace or a combustor wherein gas containing fuel and oxygen is blown to the tangential direction of the inner peripheral face of a combustion chamber to form tubular flames. <P>SOLUTION: A distance L<SB>1</SB>from a primary fuel blowing nozzle 11 to a primary oxygen containing gas blowing nozzle 12, a distance L<SB>2</SB>from the primary oxygen-containing gas blowing nozzle 12 to a secondary oxygen-containing gas blowing nozzle 13, a primary oxygen-containing gas ratio α<SB>1</SB>and a secondary oxygen-containing gas ratio α<SB>2</SB>are satisfied with a predetermined relationship during combustion. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion method using a tubular flame burner that can achieve ultra-low NOx, ultra-low SPM, and the like when a tubular flame burner is attached to a furnace or the like to perform combustion.
[0002]
[Prior art]
As a burner attached to a furnace or a combustor, a tubular flame burner called a tubular flame burner has a tubular combustion chamber whose front end is open toward the inside of the furnace, and fuel gas is placed near the closed end of the rear end of the combustion chamber. There is known a burner in which a nozzle for blowing and a nozzle for blowing an oxygen-containing gas are provided in a tangential direction of an inner peripheral surface of a combustion chamber (see, for example, Patent Document 1).
[0003]
In this tubular flame burner, the injected fuel gas and the oxygen-containing gas are mixed in a high-speed turbulent mixed state and mixed uniformly, or pass through a continuous flame zone, so NOx and SPM (floating particulate matter) It is a burner that can suppress the occurrence of low.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-281015 [0005]
[Problems to be solved by the invention]
Although the above-described tubular flame burner described in Patent Document 1 can achieve low NOx and low SPM, it cannot achieve ultra-low NOx, ultra-low SPM, and energy saving. This is particularly difficult when liquid fuel or high calorie gas fuel is used as the fuel to be injected.
[0006]
The present invention has been made to solve the above problems, and achieves ultra-low NOx, ultra-low SPM, and energy saving when burning using a tubular flame burner attached to a furnace or a combustor. It aims at providing the combustion method using the tubular flame burner which can be performed.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following features.
[0008]
[1] A tubular combustion chamber whose tip is open toward the furnace, a nozzle injection port is opened on the inner surface of the combustion chamber, and the injection direction is substantially coincident with the tangential direction of the inner peripheral surface of the combustion chamber. A combustion method using a tubular flame burner having a fuel injection nozzle and an oxygen-containing gas injection nozzle, the primary fuel injection nozzle and the primary oxygen containing from the rear end of the combustion chamber toward the furnace A combustion method using a tubular flame burner, wherein a gas blowing nozzle, a secondary oxygen-containing gas blowing nozzle, and a tertiary oxygen-containing gas blowing nozzle are arranged in this order and burned so as to satisfy the following conditions.
[0009]
k ≧ α ₁ + α ₂ + α ₃ ≧ 1.0
α ₁ ≧ β
α ₂ > 0
α ₃ ≧ 0
L ₂ ≦ L (α ₁ )
Here, α ₁ is the primary oxygen-containing gas ratio α ₂ , the secondary oxygen-containing gas ratio α ₃ is the tertiary oxygen-containing gas ratio k, and the maximum oxygen-containing gas excess β for complete combustion is The minimum oxygen-containing gas ratio L ₂ at which no soot is generated is the interval L (α ₁ ) between the primary oxygen-containing gas blowing nozzle and the secondary oxygen-containing gas blowing nozzle, and the primary oxygen-containing gas blowing nozzle and the primary oxygen-containing gas Distance from gas combustion end point [2] In the combustion method using the tubular flame burner described in “1” above, when the liquid fuel is blown from the primary fuel blowing nozzle, the position where the liquid fuel is blown and the primary oxygen A combustion method using a tubular flame burner characterized in that it is separated from the position where the contained gas is blown and mixed with the primary oxygen-containing gas after the liquid fuel is gasified.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
When performing combustion using the tubular flame burner attached to the furnace, it is desirable to perform the following combustion in order to achieve ultra-low NOx, ultra-low SPM, and energy saving.
[0011]
(A) Ultra-low NOx: Reduces not only thermal NOx but also NOx conversion by reducing the NOx conversion rate.
(1) In the ignition region, the primary oxygen-containing gas ratio is kept to a minimum.
{Circle around (2)} A secondary oxygen-containing gas is blown after a tubular flame with a primary oxygen-containing gas and a range of radical factors (CH, CH ₂ , OH, etc.) that reduce generated NOx are secured. This ensures a stable tubular flame.
(3) A tertiary oxygen-containing gas is blown in depending on the fuel calorie, NOx level, and furnace temperature level.
{Circle around (4)} Fuel is appropriately injected into the furnace as secondary fuel (decomposition combustion) and tertiary fuel (decomposition combustion). This is particularly effective when using not only liquid fuel but also high calorie gas fuel.
[0012]
(B) Ultra low SPM (1) Preheat especially when using low quality liquid fuel. Install a pre-evaporator if possible.
{Circle around (2)} When a liquid fuel is blown, a distance is required until it is mixed with the primary oxygen-containing gas after being blown and atomized.
(3) Perform uniform mixing with an excessive amount of primary oxygen-containing gas.
(4) A secondary oxygen-containing gas is blown into the fuel remaining after combustion with the primary oxygen-containing gas to further reduce the diameter of the SPM particles.
(5) Complete combustion and heat transfer in the furnace are promoted by blowing in a tertiary oxygen-containing gas. From the viewpoint of energy saving, the role of blowing in the tertiary oxygen-containing gas can be performed in the furnace.
[0013]
(C) Energy saving (1) Promote optimal heat transfer and complete combustion by optimizing SPM particle size, secondary oxygen-containing gas blowing, and tertiary oxygen-containing gas blowing.
[0014]
The present invention is intended to realize the above (A), (B), and (C), and embodiments thereof will be described below.
[0015]
(First embodiment)
FIG. 1 shows a first embodiment of the present invention. In FIG. 1, 1 is a tubular flame burner used in this embodiment, and a tip portion is attached to a furnace 2.
[0016]
The tubular flame burner 1 includes a tubular combustion chamber 10 whose front end is opened into the furnace 2, a primary fuel blowing nozzle 11 disposed in order from the rear end to the front end of the combustion chamber 10, A primary oxygen-containing gas blowing nozzle 12 and a secondary oxygen-containing gas blowing nozzle 13 are provided. The injection ports of these nozzles 11, 12, 13 are opened on the inner surface of the combustion chamber 10, and the injection direction is It almost coincides with the tangential direction of the inner peripheral surface of the combustion chamber 10.
[0017]
Gas fuel and liquid fuel are used as the primary fuel. The liquid fuel is preferably one that vaporizes at a relatively low temperature, such as kerosene, light oil, alcohol, and heavy oil A. When using a low-quality liquid fuel such as C heavy oil, it is preferable to preheat, and if possible, install a pre-evaporator to atomize the liquid fuel sufficiently.
[0018]
The oxygen-containing gas refers to a gas that supplies oxygen for combustion, such as air, oxygen, oxygen-enriched air, oxygen / exhaust gas mixture.
[0019]
The fuel to be used is defined by the injection angle θ of the primary fuel injection nozzle 11 with respect to the tube axis direction of the combustion chamber 10 and the interval L ₁ between the primary fuel injection nozzle 11 and the primary oxygen-containing gas injection nozzle 12. Set as follows according to the type.
[0020]
First, when using liquid fuel,
θ = 90 ° −Δθ (1)
L ₁ > 0 (2)
And
[0021]
That is, the primary fuel injection angle θ is directed to the rear end side of the combustion chamber 10 by a predetermined angle Δθ as shown in the equation (1), and the primary fuel injection nozzle 11 is connected to the primary fuel injection nozzle 11 as shown in the equation (2). by separating distance apart L ₁ given the primary oxygen-containing gas blowing nozzle 12, to secure the distance to the liquid fuel blown into contact with the primary oxygen-containing gas, atomization and gas of the liquid fuel After sufficient crystallization, it is mixed with the primary oxygen-containing gas. The angle Δθ and the interval L ₁ may be appropriately set depending on the type of liquid fuel, the presence / absence of preheating, and the presence / absence of the pre-evaporator, but the angle Δθ is about 5 ° to 15 °, and the interval L ₁ is the combustion chamber. About 1 to 2 times the inner diameter of 10 is preferable.
[0022]
On the other hand, when using high calorie gas fuel,
θ ≒ 90 ° (3)
L ₁ ≒ 0 (4)
And
[0023]
That is, as close to zero as possible the distance L ₁ of the primary fuel blowing nozzle 11 and the primary oxygen-containing gas blowing for nozzle 12, to promote mixing of the high-calorie gas fuel and primary oxygen-containing gas.
[0024]
The distance between the primary oxygen-containing gas blowing nozzle 12 and the primary oxygen-containing gas combustion end point (indicated by the XX line in FIG. 1) is L (α ₁ ), the primary oxygen-containing gas blowing nozzle 12 and The distance from the secondary oxygen-containing gas blowing nozzle 13 is L ₂ , the primary oxygen-containing gas ratio is α ₁ , the secondary oxygen-containing gas ratio is α ₂ , and the minimum oxygen-containing gas ratio at which no soot is generated is β (β≈0 .3) When the maximum oxygen-containing gas excess for complete combustion is k, combustion is performed so as to satisfy the following equations (5) to (8).
[0025]
k ≧ α ₁ + α ₂ ≧ 1.0 (5)
α ₁ ≧ β (6)
α ₂ > 0 (7)
L ₂ ≦ L (α ₁ ) (8)
Here, the maximum oxygen-containing gas excess ratio k for complete combustion is 1.2 to 1.3 for liquid fuel and 1.05 to 1.1 for high calorie gas fuel. Incidentally, the minimum oxygen-containing gas excess for complete combustion is 1.0.
[0026]
The primary oxygen-containing gas ratio α ₁ has an optimum value depending on the fuel used, but is preferably as small as possible within a range in which soot is not generated, and is preferably about 0.3 to 0.5.
[0027]
The secondary oxygen-containing gas ratio α ₂ may be determined so as to satisfy the above expression (5) based on the value of the primary oxygen-containing gas ratio α ₁ in order to secure a complete combustion region. .
[0028]
Further, since the distance L (α ₁ ) to the primary oxygen-containing gas combustion end point is about three times the inner diameter of the combustion chamber 10, the primary oxygen-containing gas blowing nozzle 12 and the secondary oxygen-containing gas blowing nozzle 13 The distance L ₂ is preferably about 2 to 3 times the inner diameter of the combustion chamber 10.
[0029]
If necessary, secondary fuel may be blown before the secondary oxygen-containing gas.
[0030]
Thus, in this embodiment, when combustion is performed using a tubular flame burner, combustion is performed with the fuel and oxygen-containing gas blowing positions and oxygen-containing gas ratios appropriately set. have.
[0031]
First, since the angle θ of the primary fuel blowing nozzle 11 and the distance L ₁ between the primary fuel blowing nozzle 11 and the primary oxygen-containing gas blowing nozzle 12 and the primary oxygen-containing gas ratio α ₁ are set to appropriate values, the liquid Fuel atomization and further promotion to gasification are ensured, and SPM particles are reduced in diameter.
[0032]
Since the interval L ₂ between the primary oxygen-containing gas blowing nozzle 12 and the secondary oxygen-containing gas blowing nozzle 13 and the secondary oxygen-containing gas ratio α ₂ are set to appropriate values, stable tubular flame and exhaust gas radical factor existence range is secured, together with a reducing of generating NO _X is made, recombination of SPM particles is prevented, SPM particles further reduced in diameter.
[0033]
Since complete combustion region and the second oxygen-containing gas ratio alpha ₂ to an appropriate value is to be secured, substantially complete combustion of ultra-low NO _X and SPM is obtained.
[0034]
As a result, even when liquid fuel or high-calorie gas fuel is used, combustion with ultra-low NOx and ultra-low SPM can be performed.
[0035]
(Second Embodiment)
FIG. 2 shows a second embodiment of the present invention. This embodiment is basically the same as the first embodiment, and is burned so as to satisfy the above formulas (1) to (8). In the first embodiment, however, Whereas the secondary oxygen-containing gas blowing nozzle 13 is attached to the combustion chamber 10, in this embodiment, the secondary oxygen-containing gas blowing nozzle 13 is attached to the furnace wall 2a of the furnace 2 and the secondary oxygen-containing gas. Is blown into the furnace.
[0036]
In this case, the distance L ₂ of the primary oxygen-containing gas blowing nozzle 12 and the secondary oxygen-containing gas blowing nozzle 13 becomes a distance to the inner wall surface of the primary oxygen-containing gas blowing nozzle 12 and the furnace wall 2a, the primary oxygen The end point of the contained gas combustion (shown by the XX line in FIG. 2) is positioned in the furnace 2.
[0037]
Moreover, you may make it inject | pour secondary fuel into the furnace 2 as needed.
[0038]
As a result, in this embodiment, as in the first embodiment, combustion with ultra-low NOx and ultra-low SPM can be performed, and the furnace temperature is increased by radiant heat transfer from the furnace combustion. This can save energy.
[0039]
(Third embodiment)
FIG. 3 shows a third embodiment of the present invention. In FIG. 3, reference numeral 1 denotes a tubular flame burner used in this embodiment, and a tip portion is attached to the furnace 2.
[0040]
The tubular flame burner 1 includes a tubular combustion chamber 10 whose front end is opened into the furnace 2, a primary fuel blowing nozzle 11 disposed in order from the rear end to the front end of the combustion chamber 10, A nozzle 12 for blowing primary oxygen-containing gas, a nozzle 13 for blowing secondary oxygen-containing gas, and a nozzle 14 for blowing tertiary oxygen-containing gas are provided, and the nozzles 11, 12, 13, and 14 are jet nozzles. Is opened in the inner surface of the combustion chamber 10, and the injection direction substantially coincides with the tangential direction of the inner peripheral surface of the combustion chamber 10.
[0041]
Gas fuel and liquid fuel are used as the primary fuel. The liquid fuel is preferably one that vaporizes at a relatively low temperature, such as kerosene, light oil, alcohol, and heavy oil A. When using a low-quality liquid fuel such as C heavy oil, it is preferable to preheat, and if possible, install a pre-evaporator to atomize the liquid fuel sufficiently.
[0042]
The oxygen-containing gas refers to a gas that supplies oxygen for combustion, such as air, oxygen, oxygen-enriched air, oxygen / exhaust gas mixture.
[0043]
The fuel to be used is defined by the injection angle θ of the primary fuel injection nozzle 11 with respect to the tube axis direction of the combustion chamber 10 and the interval L ₁ between the primary fuel injection nozzle 11 and the primary oxygen-containing gas injection nozzle 12. Set as follows according to the type.
[0044]
First, when using liquid fuel,
θ = 90 ° −Δθ (1)
L ₁ > 0 (2)
And
[0045]
That is, the primary fuel injection angle θ is directed to the rear end side of the combustion chamber 10 by a predetermined angle Δθ as shown in the equation (1), and the primary fuel injection nozzle 11 is connected to the primary fuel injection nozzle 11 as shown in the equation (2). by separating distance apart L ₁ given the primary oxygen-containing gas blowing nozzle 12, to secure the distance to the liquid fuel blown into contact with the primary oxygen-containing gas, atomization and gas of the liquid fuel After sufficient crystallization, it is mixed with the primary oxygen-containing gas. The angle Δθ and the interval L ₁ may be appropriately set depending on the type of liquid fuel, the presence / absence of preheating, and the presence / absence of the pre-evaporator, but the angle Δθ is about 5 ° to 15 °, and the interval L ₁ is the combustion chamber. About 1 to 2 times the inner diameter of 10 is preferable.
[0046]
On the other hand, when using high calorie gas fuel,
θ ≒ 90 ° (3)
L ₁ ≒ 0 (4)
And
[0047]
That is, as close to zero as possible the distance L ₁ of the primary fuel blowing nozzle 11 and the primary oxygen-containing gas blowing for nozzle 12, to promote mixing of the high-calorie gas fuel and primary oxygen-containing gas.
[0048]
The distance between the primary oxygen-containing gas blowing nozzle 12 and the primary oxygen-containing gas combustion end point (indicated by the XX line in FIG. 1) is L (α ₁ ), the primary oxygen-containing gas blowing nozzle 12 and The interval between the secondary oxygen-containing gas blowing nozzle 13 is L ₂ , the interval between the secondary oxygen-containing gas blowing nozzle 12 and the tertiary oxygen-containing gas blowing nozzle 13 is L ₃ , and the primary oxygen-containing gas ratio is α ₁ , 2 The secondary oxygen-containing gas ratio is α ₂ , the tertiary oxygen-containing gas ratio is α ₃ , the minimum oxygen-containing gas ratio where soot is not generated is β (β≈0.3), and the maximum oxygen-containing gas excess rate for complete combustion is When k is set, combustion is performed so as to satisfy the following expressions (9) to (13).
[0049]
k ≧ α ₁ + α ₂ + α ₃ ≧ 1.0 (9)
α ₁ ≧ β (10)
α ₂ > 0 (11)
α ₃ > 0 (12)
L ₂ ≦ L (α ₁ ) (13)
Here, the maximum oxygen-containing gas excess ratio k for complete combustion is 1.2 to 1.3 for liquid fuel and 1.05 to 1.1 for high calorie gas fuel. Incidentally, the minimum oxygen-containing gas excess for complete combustion is 1.0.
[0050]
The primary oxygen-containing gas ratio α ₁ has an optimum value depending on the fuel used, but is preferably as small as possible within a range in which soot is not generated, and is preferably about 0.3 to 0.5.
[0051]
There is an optimum value by the fuel and the combustion state even secondary oxygen-containing gas ratio alpha ₂ is used, preferably about 0.2 to 0.5.
[0052]
The tertiary oxygen-containing gas ratio α ₂ is calculated based on the values of the primary oxygen-containing gas ratio α ₁ and the secondary oxygen-containing gas ratio α ₂ in order to secure a complete combustion region. You may decide to be satisfied.
[0053]
Further, since the distance L (α ₁ ) to the primary oxygen-containing gas combustion end point is about three times the inner diameter of the combustion chamber 10, the primary oxygen-containing gas blowing nozzle 12 and the secondary oxygen-containing gas blowing nozzle 13 The distance L ₂ is preferably about 2 to 3 times the inner diameter of the combustion chamber 10.
[0054]
Further, L ₃ apart secondary oxygen-containing gas blowing nozzle 12 and the tertiary oxygen-containing gas blowing nozzle 13 is shortened if possible, preferably to the full length of the combustion chamber 10 does not become too long.
[0055]
If necessary, the secondary fuel may be blown before the secondary oxygen-containing gas, and the tertiary fuel may be blown before the tertiary oxygen-containing gas.
[0056]
Thus, in this embodiment, when combustion is performed using a tubular flame burner, combustion is performed with the fuel and oxygen-containing gas blowing positions and oxygen-containing gas ratios appropriately set. have.
[0057]
First, since the angle θ of the primary fuel blowing nozzle 11 and the distance L ₁ between the primary fuel blowing nozzle 11 and the primary oxygen-containing gas blowing nozzle 12 and the primary oxygen-containing gas ratio α ₁ are set to appropriate values, the liquid Fuel atomization and further promotion to gasification are ensured, and SPM particles are reduced in diameter.
[0058]
Since the interval L ₂ between the primary oxygen-containing gas blowing nozzle 12 and the secondary oxygen-containing gas blowing nozzle 13 and the secondary oxygen-containing gas ratio α ₂ are set to appropriate values, stable tubular flame and exhaust gas radical factor existence range is secured, together with a reducing of generating NO _X is made, recombination of SPM particles is prevented, SPM particles further reduced in diameter.
[0059]
Since complete combustion region and the second oxygen-containing gas ratio alpha ₂ and tertiary oxygen-containing gas ratio alpha ₃ to an appropriate value is to be secured, substantially complete combustion of ultra-low NO _X and SPM is obtained It is done.
[0060]
As a result, even when liquid fuel or high-calorie gas fuel is used, combustion with ultra-low NOx and ultra-low SPM can be performed more reliably.
[0061]
(Fourth embodiment)
FIG. 4 shows a fourth embodiment of the present invention. This embodiment is basically the same as the third embodiment described above, and is burned so that the expressions (1) to (4) and the expressions (9) to (13) are satisfied. However, in the third embodiment, the tertiary oxygen-containing gas blowing nozzle 14 is attached to the combustion chamber 10, whereas in this embodiment, the tertiary oxygen-containing gas blowing nozzle 14 is connected to the furnace wall of the furnace 2. Attached to 2a, a tertiary oxygen-containing gas is blown into the furnace. The attachment position of the tertiary oxygen-containing gas blowing nozzle 14 may be the front stage part of the furnace 2 close to the tubular flame burner 1 or the rear stage part of the furnace 2 away from the tubular flame burner 1.
[0062]
Note that tertiary fuel may be blown into the furnace 2 as necessary.
[0063]
As a result, in this embodiment, as in the third embodiment, combustion with ultra-low NOx and ultra-low SPM can be performed reliably, and the temperature in the furnace can be increased by radiant heat transfer from the furnace combustion. Energy saving can also be achieved by raising.
[0064]
【The invention's effect】
In the present invention, when combustion is performed using a tubular flame burner, combustion is performed by appropriately setting the blowing position of the fuel and oxygen-containing gas and the oxygen-containing gas ratio, so that ultra-low NOx, ultra-low SPM, and Energy saving combustion can be performed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a first embodiment of the present invention.
FIG. 2 is an explanatory diagram of a second embodiment of the present invention.
FIG. 3 is an explanatory diagram of a third embodiment of the present invention.
FIG. 4 is an explanatory diagram of a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tubular flame burner 2 Furnace 2a Furnace wall 10 Combustion chamber 11 Primary fuel blowing nozzle 12 Primary oxygen containing gas blowing nozzle 13 Secondary oxygen containing gas blowing nozzle 14 Tertiary oxygen containing gas blowing nozzle

Claims (2)

Tubular combustion chamber with its tip open into the furnace, a nozzle injection port that opens to the inner surface of the combustion chamber, and a fuel injection in which the injection direction substantially coincides with the tangential direction of the inner peripheral surface of the combustion chamber A combustion method using a tubular flame burner provided with a nozzle and an oxygen-containing gas blowing nozzle, the primary fuel blowing nozzle and the primary oxygen-containing gas blowing nozzle from the rear end of the combustion chamber toward the furnace A combustion method using a tubular flame burner, wherein a secondary oxygen-containing gas blowing nozzle and a tertiary oxygen-containing gas blowing nozzle are arranged in this order and burned so as to satisfy the following conditions.
k ≧ α ₁ + α ₂ + α ₃ ≧ 1.0
α ₁ ≧ β
α ₂ > 0
α ₃ ≧ 0
L ₂ ≦ L (α ₁ )
Here, α ₁ is the primary oxygen-containing gas ratio α ₂ , the secondary oxygen-containing gas ratio α ₃ is the tertiary oxygen-containing gas ratio k, and the maximum oxygen-containing gas excess β for complete combustion is The minimum oxygen-containing gas ratio L ₂ at which no soot is generated is the interval L (α ₁ ) between the primary oxygen-containing gas blowing nozzle and the secondary oxygen-containing gas blowing nozzle, and the primary oxygen-containing gas blowing nozzle and the primary oxygen-containing gas Distance from gas combustion end point In the combustion method using the tubular flame burner according to claim 1, when the liquid fuel is blown from the primary fuel blowing nozzle, the position where the liquid fuel is blown and the position where the primary oxygen-containing gas is blown are separated from each other, A combustion method using a tubular flame burner, wherein the fuel is gasified and mixed with a primary oxygen-containing gas.

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