JP2004184007A - Fine powder-like fuel combustion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fine powder-like fuel combustion device capable of providing excellent ignition and combustion performances by sufficiently developing the function of a concentrated/lean fuel separator to eliminate the unbalance of the concentration of fine powder-like fuel (fine powder coal) in the fine powder-like fuel combustion device such as a fine powder coal firing burner having an asymmetrical burner nozzle. <P>SOLUTION: This fine powder-like fuel combustion device comprises the burner nozzle 1, a fine powder coal supply tube 3, and a wind box 5 forming a combustion supporting air supply passage 4 around the fine powder-like fuel supply tube. A vertical plane passing the axis 8 of the jetting direction of the mixed flow A of fine powder coal and carrying air is tilted without crossing the side face of a furnace at a right angle. The shape of the burner nozzle is laterally asymmetrical with respect to the vertical plane, and a burner nozzle opening face 2 is positioned in the same plane as the side face of the furnace. The concentrated/lean fuel separator 31 is horizontally installed in the burner nozzle or the fine powder coal supply tube. The concentrated/lean fuel separator 31 is installed to be parallel with the side face of the furnace and laterally asymmetric with respect to the vertical plane. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pulverized fuel combustion apparatus, and is useful when applied to a pulverized fuel combustion apparatus such as a pulverized coal burning burner applied to a boiler furnace for thermal power generation, a chemical industrial furnace, or the like.
[0002]
[Prior art]
A burner nozzle that is provided on the side of a vertical rectangular tubular furnace and ejects a mixed flow of pulverized coal and air; a pulverized coal supply pipe connected to the burner nozzle to supply pulverized coal and air; A wind box forming a combustion auxiliary air supply path around a supply pipe, and a pulverized coal-burning burner in which a vertical plane passing through an axis of a direction in which the mixed flow is jetted is inclined without being orthogonal to a side surface of the furnace. In the prior art, the shape of the burner nozzle was symmetrical with respect to the vertical plane.
[0003]
However, the pulverized coal-burning burner having the symmetric burner nozzle has problems in that the furnace wall tube panel and the burner panel are not easily worked, the furnace wall support structure has a complicated structure, and maintenance is poor. Therefore, in order to solve these problems, the shape of the burner nozzle is asymmetrical with respect to the vertical plane, and the opening surface of the tip end of the burner nozzle is located in the same or parallel plane as the side surface of the furnace. A pulverized coal-burning burner equipped with a burner nozzle has been developed (see Patent Document 1).
[0004]
On the other hand, in order to simplify the entire burner by using a conc burner and a weak burner, which are conventionally provided separately, as a single burner, to improve ignition performance, reduce NOx, and reduce unburned fuel, a burner nozzle is used. A pulverized coal-cooked burner equipped with a concentration separator has also been developed (see Patent Document 2). However, the burner nozzle at this time is symmetrical with respect to a vertical plane passing through the ejection direction axis, and the density separator is also symmetrical with respect to the vertical plane.
[0005]
[Patent Document 1]
JP-A-9-49613 [Patent Document 2]
Japanese Patent No. 2781740 [0006]
[Problems to be solved by the invention]
Therefore, the present inventors have disclosed a pulverized coal-burning burner having an asymmetric burner nozzle as disclosed in Patent Literature 1, which is disclosed in Patent Literature 2, in order to realize a higher performance pulverized coal-burning burner. It was studied to provide such a density separator. However, when the density separator is simply installed in the asymmetric burner nozzle, that is, when the density separator is arranged in the asymmetric burner nozzle so as to be orthogonal to the ejection direction axis, the function of the density separator is sufficiently exhibited. However, the pulverized coal concentration became unbalanced, and as a result, poor ignition point, slag (molten ash) adhered to the burner nozzle, and poor performance of NO _X and unburned components occurred (see FIG. 6A). Details will be described later).
[0007]
Accordingly, the present invention has been made in view of the above circumstances, and in a pulverized fuel combustion device such as a pulverized coal burning burner having an asymmetric burner nozzle, the function of the concentration separator is sufficiently exhibited, and the pulverized fuel (pulverized coal) concentration is unbalanced. It is an object of the present invention to provide a pulverized fuel combustion device which can solve the above problem and obtain good ignition combustion performance.
[0008]
[Means for Solving the Problems]
A pulverized fuel combustion device of the present invention that solves the above-mentioned problems is provided on a side surface of a furnace having a vertical rectangular tube shape, and a burner nozzle or a burner throat that ejects a mixed flow of pulverized fuel and air, and the burner nozzle or A pulverized fuel supply pipe connected to a burner throat to supply pulverized fuel and air; and a wind box forming a combustion auxiliary air supply path around the pulverized fuel supply pipe, and ejecting the mixed flow. The vertical plane passing through the direction axis is inclined not orthogonal to the side surface of the furnace, the shape of the burner nozzle or the burner throat is asymmetrical with respect to the vertical plane, and the opening surface of the tip of the burner nozzle or the burner throat. Is located in a plane that is the same or parallel to the side of the furnace, and, in the burner nozzle or burner throat or in the pulverized coal supply pipe, a density separator is provided. In earnestly pulverized fuel combustion apparatus provided,
The density separator has a cross-sectional shape that gradually expands in the vertical direction toward the downstream side of the mixed flow, and then becomes parallel to the ejection direction axis, and then ends in a vertical plane, and A structure having a notch slit penetrating in the direction of jetting the mixed flow, which is provided so as to be substantially parallel to the side surface of the furnace, and characterized in that it is asymmetrical with respect to the vertical plane.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0010]
<Embodiment 1>
FIG. 1 is a horizontal sectional view showing a configuration of a pulverized coal-burning burner according to Embodiment 1 of the present invention as viewed from above, FIG. 2 is a structural conceptual view of a furnace wall tube according to Embodiment 1 of the present invention, and FIG. FIG. 4 schematically illustrates a flow state in the vicinity of the pulverized coal burning burner, and FIG. 4 is a configuration diagram of a concentration separator provided in the pulverized coal burning burner. FIGS. 5 and 6 are explanatory views showing the operation and effect of the density separator.
[0011]
As shown in FIG. 1, a burner nozzle 1 is provided on a side surface 7 of a furnace 30 (partially shown in the figure) of a vertical prismatic tubular shape. A pulverized coal supply pipe 3 as a fuel supply pipe is connected. The mixed flow A of the pulverized coal as the pulverized fuel and the carrier air passes through the pulverized coal supply pipe 3, is guided to the burner nozzle 1, and is ejected into the furnace 30 from the opening 2 at the tip end of the burner nozzle 1. Is done. The wind box 5 forms a combustion auxiliary air supply path 4 around the pulverized coal supply pipe 3. The combustion auxiliary air passes through the combustion auxiliary air supply passage 4 and is guided to the burner nozzle 1, and is jetted out of the burner nozzle opening surface 2 into the furnace 30 in the same manner as pulverized coal and carrier air.
[0012]
A vertical plane (virtual plane) passing through (including) the axis (virtual line) 8 of the jet direction of the mixed flow A is not perpendicular to the side surface 7 of the furnace 30 but is inclined. The pulverized coal, the carrier air, and the combustion auxiliary air ejected into the furnace 30 form a flame while diffusing and mixing in the furnace 30. The jet direction axis 8 of the mixed flow A is coaxial with the jet direction axis of the combustion auxiliary air.
[0013]
The burner nozzle 2 is an asymmetric burner nozzle that is asymmetrical with respect to a vertical plane (virtual plane) passing through the ejection direction axis 8. By adopting such a burner nozzle shape, the burner nozzle opening surface 2 can be located in the same plane as the furnace side surface 7 as shown in the figure, so that the furnace furnace is used as in the case of using the conventional symmetric burner nozzle. There is no need to arrange the wall tube at an angle to the side of the furnace and toward the wind box side. Even if the furnace tube 6 is configured as shown in FIGS. 1 and 2, the flame collides with the furnace tube 6. It can be burned without causing the phenomenon of licking or licking the furnace wall tube 6.
[0014]
For this reason, the furnace wall tube 6 and the burner panel are easily manufactured, and a furnace wall tube support structure having a simple structure at low cost can be adopted. Furthermore, even in the case of a large-capacity burner or a large-capacity boiler, access to the periphery of the furnace wall tube can be facilitated, and the position of the burner nozzle should be located closer to the inside of the furnace than the conventional symmetric burner nozzle. , The maintenance is improved.
[0015]
In FIG. 3, 15 is a schematic diagram of a pulverized coal supply pipe or a combustion auxiliary air supply path, 16 is a burner nozzle style diagram, and 17 arrows indicate the pulverized coal and carrier air or combustion auxiliary air jetting into the furnace in the axial direction. Velocity distribution, 18 is a schematic diagram of a furnace wall tube arranged toward the wind box side at an angle α with respect to the furnace side, and an arrow 19 is a schematic diagram of a swirling flame in the furnace.
[0016]
The pulverized coal-burning burner of the first embodiment differs from the conventional pulverized coal-burning burner using a symmetric burner nozzle in a basic flow state near the burner. First, as shown in FIG. 3A, in the first embodiment in which the burner nozzle opening surface 2 has an angle of β with respect to a surface perpendicular to the axis 8 in which the pulverized coal and the carrier air are injected into the furnace. In the burner nozzle wall surface 20 where the flow path of the jet of pulverized coal and the carrier air or combustion auxiliary air is longer, the burner in which the flow path length of the opposite wall, that is, the flow path of the jet of the pulverized coal and the carrier air or combustion auxiliary air is shorter. Since the pressure loss of the jet is larger than that of the nozzle wall 21, the jet direction of the jet deviates from the jet direction axis 8 and is deflected toward the wall 21 as shown by an arrow 22. The degree of the deflection depends on the angle β and the coefficient of frictional resistance of the wall surfaces 20 and 21.
[0017]
In addition, as shown in FIG. 3 (b), in the conventional pulverized coal-burning burner using the symmetric burner nozzle, the jet flow is affected by the furnace wall tube 18 arranged toward the wind box side at an angle α with respect to the furnace side. Tended to deflect as shown by the ejection direction axes 8 to 23, but in the first embodiment, the degree of deflection was small because the arrangement of the furnace wall tube was different from that of the furnace wall tube 18. And the jet becomes as shown at 24.
[0018]
As described above, in addition to the influence of the different flow style near the burner from the pulverized coal-cooked burner using the conventional symmetric burner nozzle, the fine powder in the first embodiment is finally produced by the influence of the furnace swirling flame 19 on the jet. It is estimated that the jet direction of the jet 22 of the charcoal burner is actually deviated from the jet direction axis 8 by a maximum of 15 to 20 degrees. Pulverized coal-burning burners using such asymmetric burner nozzles also have better ignition and combustion performance than conventional pulverized coal-burning burners using symmetric burner nozzles.
[0019]
In the first embodiment, a pulverized coal-burning burner having such an asymmetric burner nozzle 1 is provided with a core-type light / dark separator 31. The density separator 31 is provided horizontally in the burner nozzle 1 (in the case of the illustrated example) or in the central portion of the pulverized coal supply pipe 3 by an attachment member such as a fixing bracket (not shown). Moreover, the density separator 31 is provided so as to be parallel to the side surface 7 of the furnace 30 and is asymmetrical with respect to a vertical plane passing through the ejection direction axis 8.
[0020]
Here, the structure of the density separator 31 will be described in detail with reference to FIG. 4 (a) is a plan view of the density separator, FIG. 4 (b) is a view in the direction of arrow B in FIG. 4 (a), and FIG. 4 (c) is a cross section in the direction of arrows CC in FIG. 4 (a). FIG.
[0021]
As shown in FIG. 4C, the cross-sectional shape of the concentration separator 31 gradually increases in the vertical direction toward the downstream side of the mixed flow A of the pulverized coal and the carrier air (the inclined surfaces 31b and 31c), and thereafter. After being parallel to the jetting direction axis 8 of the mixed flow A (portions 31 d and 31 e), it ends in a vertical plane (portion 31 f) and cuts through the jetting direction of the mixed flow A. It has a structure having a notch slit 31a.
[0022]
More specifically, as shown in FIG. 4A, the light and shade separator 31 includes short sides on both the left and right sides parallel to the ejection direction axis 8 in a top view, and front and rear sides inclined with respect to the ejection direction axis 8. It is an elongated parallelogram having long sides. The density separator 31 is disposed in the burner nozzle 1 so that its longitudinal direction is horizontal, and the longitudinal direction is parallel to the side surface 7 of the furnace 30 (that is, parallel to the burner nozzle opening surface 2). And is asymmetrical with respect to a vertical plane passing through the ejection direction axis 8.
[0023]
As shown in FIG. 4 (c), the density separator 31 has a flat surface (inclined surface) that gradually spreads vertically toward the downstream side of the mixed flow A on the front end side (upstream of the mixed flow A). At the rear end side (downstream of the mixed flow A), there are planes (horizontal planes) 31d and 31e continuous with the inclined surfaces 31b and 31c, respectively, and parallel to the ejection direction axis 8. Is a vertical plane (vertical surface) 31f that is continuous with the horizontal planes 31d and 31e, and penetrates in the center in the direction in which the mixed flow A is ejected and has a wide horizontal width (see FIG. 4B). It has a notch slit 31a. Further, as shown in FIG. 4 (b), the left and right side surfaces 31g and 31h of the density separator 31 are curved.
[0024]
By the action of the concentration separator 31, the mixed flow A of the pulverized coal and the carrier air is separated into a mixed flow having a high pulverized coal concentration on the outer peripheral side and a mixed flow having a low pulverized coal concentration on the central side in the burner nozzle 1. Is done. The mixed stream having a high pulverized coal concentration comes into contact with the combustion auxiliary air and ignites uniformly on the outer peripheral side in the burner nozzle 1 to form a good flame. On the other hand, the mixed flow having a low pulverized coal concentration blows through the central portion in the burner nozzle 1 and ignites and burns on the downstream side (in the furnace) of the burner nozzle 1 to form a flame having a low pulverized coal concentration. Here, the region mainly contributing to the ignition is the mixed flow (pulverized coal flow) taken into the circulation vortex on the inner peripheral surface of the burner nozzle 1. The mixed stream (pulverized coal stream) that blows through the center propagates the flame later. By forming the density of the pulverized coal in the mixed flow in the burner nozzle 1 in this manner, the combustion flame becomes better than before, and the NOx reduction region in the burner flame is further increased.
[0025]
Here, the operation of the density separator 31 will be described more specifically with reference to FIG. FIG. 5A is a cross-sectional view corresponding to FIG. 4C, and is an explanatory view showing a state of shading, and FIG. 5B is a view as seen in the direction of arrow D in FIG. 5A. The dots in FIG. 5 represent pulverized coal.
[0026]
As shown in these figures, when the mixed flow A of the pulverized coal and the carrier air flowing in the pulverized coal supply pipe 3 collides with the inclined surfaces 31b and 31c of the concentration separator 31, the pulverized coal in the mixed flow A Are gathered near the inner wall surface of the burner nozzle 1 due to the inertial force. On the other hand, after the air is once separated by the density separator 31, the air returns to the axial portion (center portion) in the burner nozzle 1 behind the density separator 31. Therefore, the pulverized coal concentration is high in the outer peripheral portion (E portion) in the burner nozzle 1 and low in the axial center portion (F portion). At this time, the air that has flowed to the downstream side of the density separator 31 is likely to generate a vortex, but the vortex is generated by guiding a part of the mixed flow A into the notch slit 31a and flowing it downstream. By preventing the stagnation caused by the eddy current, a uniform flow velocity distribution can be formed, and the density separation effect can be promoted.
[0027]
Next, the shape and dimensions of the density separator 31 will be described. Here, as shown in FIG. 4, the width of the density separator 31 is d ₁ , the length of the straight pipe portion is L ₁ , the height of the rear surface is h ₁ , the angle of the mixed flow A with respect to the flow direction is θ, and the notch slit 31 a The width is d ₂ , the entrance height is h ₂ , and the exit height is h ₃ . The height of the burner nozzle 1 is d ₃ , the width is d _4, and the length from the tip of the burner nozzle 1 to the density separator 31 is L ₂ .
[0028]
The installation position of the shade separator _31, L 2 / _{d 3} 1-4, preferably 2 to 3, the optimum value is _L 2 _{/ d} 3 = 3. Ideally, the jet flow velocity is uniform at the burner nozzle opening surface 2 and only the density distribution of pulverized coal is generated. The smaller the value of L ₂ / d ₃ , the more the density distribution occurs, but the flow velocity distribution becomes non-uniform. Conversely, when L ₂ / d ₃ increases, the flow velocity becomes uniform, but no light / dark distribution occurs. _Accordingly, the scope of the L ₂ / d 3 = 1~4 is proper range. The relationship between the width _{d 1} and the inner width _{d 4} of the burner nozzle 1 shades separator _31, d ₁ / d 4 = 0.9 to 1.0 is preferred.
[0029]
The angle θ of the density separator 31 can be in the range of 35 ° to 45 °, but θ = 45 ° is most preferable. The larger θ is, the higher the separation efficiency is, but the higher the pressure loss is. The relationship width _{d 2} of the width _{d 1} and notch slit 31a of the shading separator 31 is desirably _{d 2 / d 1 = 0.7~1.0,} d 2 / d 1 = 0.9 is most preferred . This is because if d ₂ / d ₁ is small, a vortex is generated on the side surface of the density separator 31 and entrainment of the pulverized coal increases. Further, rear surface relationship height _{h 1} and the straight portion length _{L 1} of the gray separator 31 is in the range of _{h 1 / L 1 = 1~2,} h 1 / L 1 = 2 is preferable. This is because if h ₁ / L ₁ is too large, the vortex in the downstream part of the concentration separator becomes large, the entrainment of pulverized coal increases, and the separation efficiency decreases. The relationship between rear surface height _{h 1} of the height _h 2, _{h 3} and shades separator 31 of the notched slit 31a is _{h 1 = 2.5h 3, h 3} = 2h 2 is preferred.
[0030]
In the first embodiment, instead of disposing the density separator 31 so as to be orthogonal to the vertical plane passing through the ejection direction axis 8, the concentration separator 31 is set so as to be parallel to the side surface 7 of the furnace 30 as described above. When the mixed flow of pulverized coal and carrier air is injected into the furnace 30 from the burner nozzle opening surface 2 in the furnace 30, the pulverized coal in the region where the pulverized coal concentration is high on the outer peripheral side is asymmetric with respect to the vertical plane. The concentration distribution can be made uniform.
[0031]
That is, as shown in FIG. 6A, when the density separator 31 is arranged so as to be orthogonal to the vertical plane passing through the ejection direction axis 8, from the left and right ends of the density separator 31 to the burner nozzle opening surface 2. When there is a large difference between the distances L ₃ and L ₄ , when a mixed flow of pulverized coal and carrier air is ejected from the burner nozzle opening surface 2, the pulverized coal concentration distribution in the region where the pulverized coal concentration is high on the outer peripheral side is: Imbalance will occur at the left and right sides E ₁ and E ₂ corresponding to the left and right ends of the density separator 31. In other words, those of E ₁ side is denser pulverized coal concentration, those of E ₂ side becomes thinner pulverized coal concentration. Therefore, the ignition point defects occur in the thin E ₂ side of the pulverized coal concentration, slag to the burner nozzle 1 (molten ash) deposition occurs. In addition, NO _X · unburned performance becomes defective.
[0032]
When the density separator 31 is slightly tilted as shown in FIG. 6B, that is, when the density separator 31 is parallel to the side surface 7 of the furnace 30 as shown in FIG. when the angle between the vertical plane theta (e.g. 38 °), θ / 2 (e.g., 19 ° C.) when tilted only be, although observed some improvement, so E ₁ side and E ₂ side It was not possible to eliminate the imbalance in pulverized coal concentration.
[0033]
On the other hand, as shown in FIG. 6C, when the density separator 31 is made parallel to the side surface 7 of the furnace 30, that is, the angle formed between the density separator 31 and the vertical plane is determined by the burner nozzle opening surface 2. When the angle θ with respect to the vertical plane is the same as the angle θ (for example, 38 °), the distances L ₃ and L ₄ from the left and right ends of the density separator 31 to the burner nozzle opening surface 2 become equal. imbalance of the pulverized coal concentration of ₁ side and E ₂ side is eliminated, uniform pulverized coal concentration distribution is obtained in the dark regions of the pulverized coal concentration on the outer peripheral side. As a result, good ignition combustion performance is obtained gone ignition point defects, slag to the burner nozzle 1 (molten ash) adhesion and NO X _· unburnt poor performance was also eliminated.
[0034]
<Embodiment 2>
FIG. 7 is a horizontal sectional view showing a configuration of a pulverized coal-burning burner according to Embodiment 2 of the present invention as viewed from above. The pulverized coal-burner of the second embodiment is an example in which a burner throat is used instead of the burner nozzle 1 of the first embodiment. In FIG. 7, 9 is a burner throat, 10 is an opening surface at the tip end of the burner throat 9, 11 is an extension surface (virtual surface) of the furnace side surface 7, and other symbols are defined as in FIG.
[0035]
The burner throat 9 can be formed of a refractory material or the like. The shape of the burner throat 9 is asymmetrical with respect to the vertical plane passing through the ejection direction axis 8 as a symmetrical surface, as in the case of FIG. Embodiment 2 is a case where the burner throat opening surface 10 is not in the same plane as the furnace side surface 7 and the extension surface 11 of the furnace side surface 7, but is located in a parallel plane near these surfaces.
[0036]
Also in this pulverized coal-burning burner, similarly to the case of FIG. 1, the density separator 31 is mounted in the burner throat 9 (in the case of the illustrated example) or in the pulverized coal supply pipe 3 by an attachment member such as a fixing bracket (not shown). It is arranged horizontally at the center and is provided so as to be parallel to the furnace side surface 7, and is asymmetrical with respect to a vertical plane passing through the ejection direction axis 8.
[0037]
Therefore, also in the pulverized coal-burning burner of the second embodiment, the same operation and effect as in the first embodiment can be obtained.
[0038]
<Embodiment 3>
FIG. 8 is a horizontal sectional view showing a configuration of a pulverized coal-burning burner according to Embodiment 3 of the present invention as viewed from above. The pulverized coal-burning burner of the third embodiment has a swirler-type disperser 13 installed on the bent portion 12 connected to the pulverized coal supply pipe 3 or on the burner nozzle 1 side of the bent portion 12. The mixed flow of the pulverized coal and the carrier air that has flowed into the bent portion 12 from the direction of the arrow causes a density distribution due to the centrifugal force at the bent portion 12, and the concentration of the pulverized coal increases on the outer peripheral side of the bent portion 12, and conversely, Although the concentration of the pulverized coal becomes thinner on the peripheral side, the mixed flow having the density distribution is dispersed by the operation of the swirler type disperser 13 so that the pulverized coal concentration distribution becomes uniform.
[0039]
In this pulverized coal-burning burner as well, as in the case of FIG. 1, the concentration separator 31 is mounted in the burner nozzle 1 (in the case of the illustrated example) or in the pulverized coal supply pipe 3 by an attachment member such as a fixture (not shown). It is arranged horizontally at the center and is provided so as to be parallel to the furnace side surface 7, and is asymmetrical with respect to a vertical plane passing through the ejection direction axis 8.
[0040]
Therefore, also in the pulverized coal-burning burner of the third embodiment, the same operation and effect as those of the first embodiment can be obtained.
[0041]
It is considered that the concentration separator 31 is most preferably parallel to the furnace side 7 as in the above embodiment, but is not necessarily limited to this, and may be substantially parallel to the furnace side 7. That is, the effect can be expected even when the inclination angle of the density separator 31 is set to θ as shown in FIG. 6C, for example, when the inclination angle is slightly smaller than θ or slightly larger than θ.
[0042]
【The invention's effect】
As described above in detail with the embodiments, according to the pulverized fuel combustion apparatus of the present invention, the pulverized fuel combustion apparatus is provided on the side surface of a vertical rectangular furnace, and ejects a mixed flow of pulverized fuel and air. A burner nozzle or burner throat, a pulverized fuel supply pipe connected to the burner nozzle or burner throat to supply pulverized fuel and air, and a wind forming a combustion auxiliary air supply path around the pulverized fuel supply pipe With a box, the vertical plane passing through the jet direction axis of the mixed flow is inclined not orthogonal to the side surface of the furnace, and the shape of the burner nozzle or burner throat is left-right asymmetric with respect to the vertical plane, The tip opening surface of the burner nozzle or burner throat is located in the same or parallel plane as the side surface of the furnace, and in the burner nozzle or burner throat. In the pulverized fuel combustion device in which a concentration separator is provided horizontally in the pulverized coal supply pipe, the concentration separator has a cross-sectional shape gradually expanding in the vertical direction toward the downstream side of the mixed flow. After that, after being parallel to the ejection direction axis, the structure has a notch slit that ends in a vertical plane and penetrates in the ejection direction of the mixed flow, and is substantially parallel to the side surface of the furnace. When the mixed flow of pulverized coal and carrier air is injected into the furnace from the burner nozzle opening surface, the pulverized coal on the outer peripheral side is characterized in that the pulverized coal is The distribution of pulverized coal concentration in the region of high concentration can be made uniform, and as a result, good ignition performance is obtained without ignition point failure, and slag (molten ash) to the burner nozzle or burner throat Wear and NO X _· unburned poor performance can also be eliminated.
[Brief description of the drawings]
FIG. 1 is a horizontal cross-sectional view showing a configuration of a pulverized coal-burning burner according to Embodiment 1 of the present invention as viewed from above.
FIG. 2 is a structural conceptual diagram of a furnace wall tube according to Embodiment 1 of the present invention.
FIG. 3 is a diagram schematically illustrating a flow state in the vicinity of the pulverized coal burning burner.
FIG. 4 is a configuration diagram of a concentration separator provided in the pulverized coal burning burner.
FIG. 5 is an explanatory view showing the operation and effect of the concentration separator.
FIG. 6 is an explanatory diagram showing the operation and effect of the density separator.
FIG. 7 is a horizontal sectional view showing a configuration of a pulverized coal burning burner according to Embodiment 2 of the present invention as viewed from above.
FIG. 8 is a horizontal sectional view showing a configuration of a pulverized coal-burning burner according to Embodiment 3 of the present invention as viewed from above.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Burner nozzle 2 Burner nozzle opening surface 3 Pulverized coal supply pipe 4 Combustion auxiliary air supply path 5 Wind box 6 Furnace wall tube 7 Furnace side surface 8 Axis direction of jet of mixed flow 9 Burner throat 10 Burner throat opening surface 11 Extension surface of furnace side surface 12 Bent portion 13 Swirler type disperser 15 Schematic diagram of pulverized coal supply pipe or combustion auxiliary air supply channel 16 Burner nozzle style diagram 17 Speed distribution 18 Schematic diagram of furnace wall tube 19 Schematic diagram of swirl flame in furnace 20 and 21 burner nozzle Wall surfaces 22, 23, 24 Jet direction 30 Furnace 31 Shade separator 31a Notch slits 31b, 31c Inclined surfaces 31d, 31e Horizontal surface 31f Rear surface (vertical plane)
31g, 31h side

Claims (1)

A burner nozzle or burner throat provided on a side surface of a vertical prismatic furnace for ejecting a mixed flow of pulverized fuel and air, and fine powder connected to the burner nozzle or burner throat to supply pulverized fuel and air Fuel supply pipe, and a wind box forming a combustion auxiliary air supply path around the fine powder fuel supply pipe, and the vertical plane passing through the jet direction axis of the mixed flow is not orthogonal to the side surface of the furnace. And the shape of the burner nozzle or burner throat is asymmetrical with respect to the vertical plane, and the tip opening surface of the burner nozzle or burner throat is located in the same or parallel plane as the side surface of the furnace. And, in the pulverized fuel combustion device in which a concentration separator is provided horizontally in the burner nozzle or burner throat or in the pulverized coal supply pipe,
The density separator has a cross-sectional shape that gradually expands in the vertical direction toward the downstream side of the mixed flow, and then becomes parallel to the ejection direction axis, and then ends in a vertical plane, and A pulverized fuel having a notch slit penetrating in a direction in which the mixed flow is ejected, provided so as to be substantially parallel to a side surface of the furnace, and being asymmetrical with respect to the vertical plane; Combustion equipment.

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