JP2019128080A - Combustion burner, combustion device, and boiler - Google Patents

Abstract

To improve workability of maintenance work of a fuel nozzle in a combustion burner, a combustion device and a boiler.SOLUTION: The combustion burner comprises: a fuel nozzle 61 for ejecting a fuel gas 301; a combustion air nozzle 62 for ejecting a fuel gas combustion air 302 from an outside of the fuel nozzle 61; and a flame stabilizer 64 for widening the ejection direction of the fuel gas 301. The flame stabilizer 64 has first flame stabilization members 71 arranged on the upstream side of an opening part 61b of the fuel nozzle 61 in the fuel gas 301 ejection direction, and second flame stabilization members 72 arranged on the downstream side of the first flame stabilization members 71 in the fuel gas 301 ejection direction, and adjacently to the first flame stabilization members 71. The first flame stabilization members 71 have only a first widened section 82 whose width increases toward the downstream side in the direction of the flow of the fuel gas 301.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a combustion burner which mixes and burns fuel and air, a combustion device which forms a flame flow by the combustion burner, and a boiler which generates steam by combustion gas generated by the combustion device.

  The conventional boiler has a hollow shape and has a vertically installed furnace, and a plurality of combustion burners are arranged circumferentially and vertically on the furnace wall. And a flue is connected with the upper part of this furnace, and the heat exchanger for collecting the heat of exhaust gas and producing steam is arranged in this flue. The combustion burner is supplied with a mixture of pulverized fuel and pulverized primary fuel such as coal, and is supplied with high temperature secondary air, and this mixture and the secondary air are blown into the furnace. Form a flame.

  As a combustion burner applied to such a boiler, there is, for example, one described in Patent Document 1 below. The combustion burner described in Patent Document 1 is provided with a pulverized coal burner, a coal primary port, a coal secondary port, and a split member, and the split member collides with the pulverized coal concentrated stream to be stable in a wide load range. Enables low NOx combustion.

Japanese Patent Application Laid-Open No. 2011-127836

  However, in the combustion burners described in Patent Documents 1 and 2 described above, in maintenance work for the wear of the flame holder, a plurality of flame holders are arranged at predetermined intervals at the tip of the fuel nozzle, and the working space is sufficient. This is not ensured, and maintenance workability is reduced.

  In view of the above-described circumstances, some embodiments of the present invention aim to improve the workability of maintenance work of a fuel nozzle.

  A combustion burner according to at least one embodiment of the present invention includes a fuel nozzle that ejects a fuel gas in which fuel and air are mixed, a combustion air nozzle that ejects air from the outside of the fuel nozzle, and an ejection of the fuel nozzle A first flame stabilizing member disposed on the upstream side of the fuel gas ejection direction from the opening to widen the fuel gas ejection direction, and the fuel gas ejection direction downstream of the first flame holding member and the first flame stabilizing member A second flame holding member disposed adjacent to the flame holding member and widening the jet direction of the fuel gas, wherein at least one of the first flame holding member and the second flame holding member is a fuel gas It is characterized by having only a widening portion which widens toward the downstream side in the flow direction.

  According to the above configuration, at least one of the first flame holding member and the second flame holding member can be reduced in size, and a working space portion is secured in the fuel nozzle. Therefore, maintenance work such as cleaning, repair, and replacement of the flame stabilizing member can be performed using this work space portion, and the workability of the maintenance work of the fuel nozzle can be improved.

  In some embodiments, in the above-described configuration of the combustion burner, the first flame stabilizing member includes only a first widening portion that widens toward the downstream side of the flow direction of the fuel gas, and the second flame stabilizing member The member is characterized by having a second widening portion which widens toward the downstream side in the flow direction of the fuel gas, and a second flat portion connected to the upstream side in the flow direction of the fuel gas from the second widening portion. And

  According to the said structure, a working space part can be ensured inside a fuel nozzle by forming a 1st flame holding member only by a 1st widening part. Therefore, the flame stabilizing member can be accessed from the base end side of the fuel nozzle through the working space, and maintenance work such as cleaning, repair, and replacement of the flame stabilizing member can be easily performed.

  In some embodiments, in the configuration of the combustion burner described above, the first flame holding member has a first widened portion that widens toward the downstream side in the flow direction of the fuel gas, and a fuel gas from the first widened portion. And a first flat portion connected to the upstream side in the flow direction, and the second flame stabilizing member has only a second widening portion that widens toward the downstream side in the flow direction of the fuel gas. I assume.

  According to the above configuration, by forming the second flame stabilizing member with only the second widening portion, the first and second flame stabilizing members can be accessed from the base end side of the fuel nozzle through the working space portion. it can. Therefore, maintenance work such as cleaning, repair and replacement of the flame stabilizing member can be easily performed.

  In some embodiments, in the above-described configuration of the combustion burner, a plurality of the first flame stabilizing members are provided at predetermined intervals in the horizontal direction or the vertical direction, and the second flame stabilizing members are the first flame retaining members. A third flame-holding member is disposed between the plurality of first flame-holding members, and is provided on both sides of the fuel nozzle on the inner wall surface side of the fuel nozzle. It is characterized in that only the third widening portion which widens toward the downstream side in the gas flow direction is provided.

  According to the above configuration, a plurality of first flame holding members, a second flame holding member, and a third flame holding member are alternately provided at predetermined intervals, and the third flame holding member disposed at the center is only the third widening portion With the above configuration, the first and second flame stabilizing members can be accessed from the central portion through the working space portion from the proximal end side of the fuel nozzle. Therefore, maintenance work such as cleaning, repair and replacement of the flame stabilizing member can be easily performed.

  In some embodiments, in the above-described configuration of the combustion burner, the first flame stabilizing member includes only a first widening portion that widens toward the downstream side of the flow direction of the fuel gas, and the second flame stabilizing member The member is characterized by having only the second widened portion that widens toward the downstream side in the fuel gas flow direction.

  According to the above configuration, by forming the first flame stabilizing member and the second flame stabilizing member with only the widened portion, the first and second flame stabilizing members can be formed from the base end side of the fuel nozzle through the working space portion. It can be accessed. Therefore, maintenance work such as cleaning, repair and replacement of the flame stabilizing member can be easily performed.

  In some embodiments, in the above-described configuration of the combustion burner, the second flame stabilizing member is disposed on both sides in the widthwise direction of the first flame stabilizing member, and the first flame stabilizing member is configured to eject a fuel gas. The second widening member provided on the inner wall surface side of the fuel nozzle is provided with the first widening portion that widens the direction in two directions, and the fuel gas is ejected only on the axial center side of the fuel nozzle. The second widened portion that widens is provided.

  According to the above configuration, the fuel gas spreads in at least two directions by the first flame holding member to form a recirculation region, and the second flame holding member spreads only to the first flame holding member to form a recirculation region. As a result, the external flame holding in the fuel nozzle can be suppressed and the amount of NOx generation can be reduced.

  In the combustion apparatus according to at least one embodiment of the present invention, a plurality of the combustion burners are disposed circumferentially at predetermined intervals to form a flame swirl flow.

  According to the above configuration, in each combustion burner, the flame holding member can be accessed from the base end side of the fuel nozzle through the work space, and maintenance work such as cleaning, repairing, and replacement of the flame holding member can be performed. It can be easily implemented.

  Moreover, the boiler which concerns on at least 1 embodiment of this invention is equipped with the furnace which makes | forms a hollow shape and is installed along a perpendicular direction, and the said combustion apparatus, It is characterized by the above-mentioned.

  According to the above configuration, at each combustion burner of the furnace, the flame holding member can be accessed from the base end side of the fuel nozzle through the working space, and maintenance such as cleaning, repair, replacement of the flame holding member Work can be carried out easily.

  According to at least one embodiment of the present invention, the workability of the maintenance operation of the fuel nozzle can be improved.

It is a front view showing the composition of one embodiment of the combustion burner concerning some embodiments. It is a horizontal section (II-II section of Drawing 1) showing composition of one embodiment of a combustion burner concerning some embodiments. It is a horizontal sectional view which shows the structure of the combustion burner which concerns on other embodiment. It is a horizontal sectional view which shows the structure of the combustion burner which concerns on other embodiment.

  Several embodiments of the present invention will now be described with reference to the accompanying drawings. However, the component parts etc. which are described as embodiment, or shown by drawing are not the meaning which limits the scope of the present invention to this, but are only an illustration example. Moreover, what is comprised combining an embodiment is also included.

  FIG. 1 is a front view showing the configuration of an embodiment of a combustion burner according to some embodiments. FIG. 2 is a horizontal cross-sectional view (II-II cross-section in FIG. 1) showing the configuration of one embodiment of the combustion burner according to some embodiments.

  In the embodiment shown in FIGS. 1 and 2, the combustion burner 21 is provided with a fuel nozzle 61, a combustion air nozzle 62, and a secondary air nozzle 63 from the center side, and the flame holding in the fuel nozzle 61. A vessel 64 is provided.

  The fuel nozzle 61 is capable of spouting a pulverized fuel mixture (hereinafter referred to as fuel gas) 301 in which pulverized coal (solid fuel) and transport air (primary air) are mixed. The combustion air nozzle 62 is disposed outside the fuel nozzle 61, and can eject part of the combustion air (air for fuel gas combustion) 302 to the outer peripheral side of the fuel gas 301 ejected from the fuel nozzle 61. is there. The secondary air nozzle 63 is disposed outside the combustion air nozzle 62, and a part of the combustion air (hereinafter, secondary air) on the outer peripheral side of the fuel gas combustion air 302 jetted from the combustion air nozzle 62 It is possible to spout 303.

  The flame holder 64 is disposed inside the fuel nozzle 61 and at the tip of the fuel nozzle 61, that is, on the downstream side in the flow direction of the fuel gas 301, and thus for ignition and flame holding of the fuel gas 301. It functions as a member. The flame stabilizer 64 is composed of two first flame stabilizing members 71, two second flame stabilizing members 72, and one third flame stabilizing member 73. The first flame stabilizing member 71, the second flame stabilizing member 72, and the third flame stabilizing member 73 are disposed along the flow direction of the fuel gas 301 and along the vertical direction, and at predetermined intervals in the horizontal direction. It is arranged.

  The first flame stabilizing member 71 is a tip end portion of the fuel nozzle 61, and both sides in the radial direction (in the fuel nozzle 61) with respect to a center line O along the ejection direction of the fuel gas 301 (center line of the fuel nozzle 61). It is disposed on the wall surface 61a side and spaced from the inner wall surface 61a of the fuel nozzle 61 by a predetermined distance (a gap), and has a plate shape along the vertical direction and along the ejection direction of the fuel gas 301. The second flame stabilizing member 72 is a tip end portion of the fuel nozzle 61, and has a predetermined interval (a gap) on both sides (the inner wall surface 61a side of the fuel nozzle 61) in the horizontal direction with respect to each first flame stabilizing member 71. And a predetermined interval (space) from the inner wall surface 61a of the fuel nozzle 61, and has a plate shape along the vertical direction and along the ejection direction of the fuel gas 301. The third flame stabilizing member 73 is a tip end portion of the fuel nozzle 61, and on the center line O (center line of the fuel nozzle 61) along the ejection direction of the fuel gas 301, and from each first flame stabilizing member 71 It is disposed at a predetermined interval (gap), and has a plate shape along the vertical direction and along the ejection direction of the fuel gas 301.

  The fuel nozzle 61 and the combustion air nozzle 62 have an elongated tubular structure. The fuel nozzle 61 forms a fuel gas flow path P1 extending in the longitudinal direction and having the same flow path cross-sectional shape by four flat inner wall surfaces 61a, and has a rectangular shape at the tip end (downstream end). The opening 61 b of the The combustion air nozzle 62 extends in the longitudinal direction by the four flat outer wall surfaces 61 c of the fuel nozzle 61 and the four flat inner wall surfaces 62 a so as to have the same flow channel cross-sectional shape P 2 And a rectangular ring-shaped opening 62b is provided at the tip (downstream end). Therefore, the fuel nozzle 61 and the combustion air nozzle 62 have a double tubular structure.

  The secondary air nozzle 63 has an elongated tubular structure disposed outside the fuel nozzle 61 and the combustion air nozzle 62. The secondary air nozzle 63 has a tubular structure having four rectangular cross-sectional shapes, and is a secondary air nozzle main body 63a, 63b, disposed independently above, below, to the left, to the right of the combustion air nozzle 62. 63c and 63d and is disposed outside the combustion air nozzle 62 with a predetermined gap. The secondary air nozzles 63 extend in the longitudinal direction by the four secondary air nozzle bodies 63a, 63b, 63c, 63d, and have four secondary air flow paths P31, P32, P33 having the same flow passage cross sectional shape. , P34, and a rectangular ring-shaped opening 63e is provided at the tip (downstream end).

  The shapes of the fuel nozzle 61 and the combustion air nozzle 62 are not limited to a square, but may be a rectangle. In this case, the corner may have a curved shape. The strength of the nozzle can be improved by forming a tubular structure in which the corners are curved. Furthermore, it may be a cylinder.

  Therefore, an opening 62b of the combustion air nozzle 62 (combustion air flow path P2) is disposed outside the opening 61b of the fuel nozzle 61 (fuel gas flow path P1), and this combustion air nozzle 62 (combustion air flow path P2). The opening 63e of the secondary air nozzle 63 (secondary air flow path P3) is disposed outside the opening 62b of the air flow path P2) at a predetermined interval. The fuel nozzle 61, the combustion air nozzle 62, and the secondary air nozzle 63 are arranged such that the openings 61b, 62b, and 63e are aligned at the same position in the flow direction of the fuel gas 301 and the air.

  Incidentally, the secondary air nozzle 63 may be disposed in a rectangular shape as a double tubular structure outside the combustion air nozzle 62 without being configured by the four secondary air nozzle bodies 63a, 63b, 63c, 63d. Good. Further, although the secondary air nozzle 63 is configured by the secondary air nozzle main bodies 63a, 63b, 63c, 63d, only the upper and lower secondary air nozzle main bodies 63a, 63b are used, and the left and right secondary air nozzle main bodies 63c, 63d You may leave it alone. Furthermore, the secondary air nozzle 63 may adjust the ejection amount of the secondary air 303 by providing a damper opening degree adjustment mechanism or the like in each of the secondary air nozzle bodies 63a, 63b, 63c, 63d.

  Here, the flame holder 64 will be described in detail. The first flame stabilizing member 71 has a first widening portion 82 whose width is expanded toward the downstream side of the flow direction of the fuel gas 301 in a cross-sectional shape (FIG. 2) broken along the horizontal direction. The 1 widening portion 82 has a triangular prism shape. That is, the first wide part 82 has a horizontal cross section in the form of a substantially isosceles triangle, and is inclined inward in the width direction (the center line O side of the fuel nozzle 61) and the outside in the width direction (fuel It has a second guide surface 82b inclined to the inner wall surface 61a side of the nozzle 61, and an end surface 82c orthogonal to the flow direction of the fuel gas 301 on the front end side. The flow of the fuel gas 301 is separated at the corner formed by the guide surfaces 82a and 82b and the end surface 82c. In this case, the width of the first widening portion 82 is constant along the vertical direction, but the width may be different. The first guide surface 82a, the second guide surface 82b, and the end surface 82c are preferably flat surfaces, but may be surfaces bent or curved in a concave or convex shape.

  The second flame holding member 72 has a second flat portion 83 having a constant width and a front end portion of the second flat portion 83 (flow of the fuel gas 301) in a cross-sectional shape (FIG. 2) broken along the horizontal direction. And a second widening portion 84 integrally provided at the downstream end in the direction. The second flat portion 83 has a constant width along the flow direction of the fuel gas 301. The second widening portion 84 increases in width in the flow direction of the fuel gas 301. The second widening portion 84 has a horizontal cross section in a substantially isosceles triangle shape, the base end portion is connected to the second flat portion 83, and the tip end portion is wide toward the downstream side in the flow direction of the fuel gas 301 The front end is a plane perpendicular to the flow direction of the fuel gas 301. That is, the second widening portion 84 has a first guide surface 84a inclined to the inside in the width direction (the center line O side of the fuel nozzle 61) and an end surface 84c on the front end side. There is no guide surface on the inner wall surface 61a side of the fuel nozzle 61, and the end surface of the second flat portion 83 is a flat surface. The flow of the fuel gas 301 is separated at the corner formed by the guide surface 84 a and the end surface 84 c. In this case, the width of the second widening portion 84 is constant along its longitudinal direction (vertical direction), but may be different. By making the second widening portion 84 smaller, the internal ignition can be relatively strengthened. The first guide surface 84 a and the end surface 84 c are preferably flat surfaces, but may be surfaces bent or curved in a concave or convex shape.

  The third flame holding member 73 has a third flat portion 85 having a constant width and a front end portion of the third flat portion 85 (flow of the fuel gas 301) in a cross-sectional shape broken along the horizontal direction (FIG. 2). And a third widening portion 86 integrally provided at the downstream end in the direction. The third flat portion 85 has a constant width along the flow direction of the fuel gas 301. The third widening portion 86 increases in width in the flow direction of the fuel gas 301. The third widening portion 86 has a substantially isosceles triangular horizontal cross section, the base end portion is connected to the third flat portion 85, and the tip end portion is wide toward the downstream side in the flow direction of the fuel gas 301 The front end is a plane perpendicular to the flow direction of the fuel gas 301. That is, the third widening portion 86 includes a first guide surface 86a inclined to the one first flame stabilizing member 71 side, a second guide surface 86b inclined to the other first flame stabilizing member 71 side, and a front end side. And an end face 86c. The flow of the fuel gas 301 is separated at the corner formed by the guide surfaces 86a and 86b and the end surface 86c. In this case, the width of the third widening portion 86 is constant along the longitudinal direction (vertical direction), but the width may be different. The first guide surface 86a, the second guide surface 86b, and the end surface 86c are preferably flat surfaces, but may be surfaces bent or curved in a concave or convex shape.

  In this case, as described above, the first flame stabilizing member 71, the second flame stabilizing member 72, the third flame stabilizing member 73, and the inner wall surface 61a of the fuel nozzle 61 are arranged with a predetermined gap therebetween. However, the predetermined interval is at least a gap larger than the width of the widened portions 82, 84, 86 in the flame holding members 71, 72, 73, or at least the widened portions 82, 84, 86 in the flame holding members 71, 72, 73. Are gaps that do not interfere (contact) with each other or with the inner wall surface 61 a of the fuel nozzle 61 due to heat expansion.

  In the fuel nozzle 61, first, second and third flame stabilizing members 71, 72 and 73 as the flame stabilizer 64 are disposed at predetermined intervals in the width direction (horizontal direction). The second and third flame stabilizing members 72 and 73 are provided with widening portions 84 and 86 at their tip portions, respectively, and in the widening portions 84 and 86, the end faces 84c and 86c correspond to the opening of the fuel nozzle 61. 61 b and the same position in the flow direction of the fuel gas 301 are arranged on the same plane. On the other hand, the first flame stabilizing member 71 is provided with a first widening portion 82 at its front end portion, and the first widening portion 82 has an end face 82c in the ejection direction of the fuel gas 301 from the opening 61b of the fuel nozzle 61. It is located upstream. That is, in the second and third flame stabilizing members 72 and 73, the end faces 84c and 86c of the widened portions 84 and 86 and the opening 61b of the fuel nozzle 61 are at the same position in the ejection direction of the fuel gas 301. In the first flame stabilizing member 71, the end face 82c of the first widening part 82 is predetermined on the upstream side of the fuel gas 301 in the ejection direction with respect to the opening 61b of the fuel nozzle 61 (the end faces 84c and 86c of the widening parts 84 and 86). It is disposed at a position separated by a distance L.

  The first, second, and third flame stabilizing members 71, 72, 73 are supported by welding or the like on the inner wall surface 61a of the fuel nozzle 61 via the supporting members 87, 88 at the upper end and lower end of the rear portion There is. The support members 87 and 88 are fixed to the upper and lower portions of the inner wall surface 61a of the fuel nozzle 61, and the upper and lower end portions of the first, second and third flame stabilizing members 71, 72 and 73 support this support. It is supported by members 87 and 88.

  In this case, the first, second, and third flame holding members 71, 72, and 73 are fixed to support members 87 and 88 that are fixed to the inner wall surface 61 a of the fuel nozzle 61. However, the present invention is not limited to this configuration. For example, the first flame stabilizing member 71 is disposed at a position where the end surface 82 c of the first wide portion 82 is retracted by a predetermined distance L from the opening 61 b of the fuel nozzle 61. It is conceivable to change the predetermined distance L of the position of the first widening portion 82 in accordance with the type of fuel, the amount of ejection, and the like. Therefore, it is desirable to provide the first flame stabilizing member 71 so as to be adjustable in position along the ejection direction of the fuel gas 301.

  In the fuel nozzle 61, the first, second, and third flame stabilizing members 71, 72, 73 are supported by the supporting members 87, 88 as the flame holder 64, so that the area where the fuel gas flow path P1 has six is provided. Will be divided. That is, the fuel gas flow path P 1 includes the first fuel gas flow path P 11 between the third flame holding member 73 and each of the first flame holding members 71, the first flame holding member 71 and the second flame holding member 72. And the third fuel gas flow path P13 between the second flame holding member 72 and the inner wall surface 61a of the fuel nozzle 61.

  In addition, since the support members 87 and 88 support the flame stabilizing members 71, 72, 73, they do not affect the flow of the fuel gas 301, and the flame retaining members 71, 72, 73 The width (thickness) is set to be as small as possible (thin thickness). Further, the circumferential support position where the flame stabilizing members 71, 72, 73 are supported by the supporting members 87, 88 is not limited to the embodiment.

  In some embodiments, the second flame holding member 72 and the third flame holding member 73 are arranged between the second flame holding member 72 and the third flame holding member 73 although there are flat portions 83 and 85. The first flame stabilizing member 71 does not have a flat portion and is constituted only by the first widening portion 82. Therefore, the first flame stabilizing member 71 is miniaturized, and a working space is secured behind each of the flame stabilizing members 71, 72, 73. The operator can access the flame stabilizing members 71, 72, 73 from the base end side of the fuel nozzle 61, and can easily carry out maintenance work such as cleaning, repair, and replacement of the flame holder 64. it can.

  FIG. 3 is a horizontal sectional view showing the configuration of a combustion burner according to another embodiment. The members having the same functions as those in the above-described embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

  A combustion burner 21A according to an embodiment shown in FIG. 3 is provided with a fuel nozzle 61, a combustion air nozzle 62, and a secondary air nozzle 63 from the center side, and a flame holder 64A is provided in the fuel nozzle 61. It is done.

  The flame holder 64 </ b> A includes two first flame holding members 71, two second flame holding members 72, and one third flame holding member 73. The first flame stabilizing member 71, the second flame stabilizing member 72, and the third flame stabilizing member 73 are disposed along the flow direction of the fuel gas 301 and along the vertical direction, and at predetermined intervals in the horizontal direction. It is arranged.

  The first flame stabilizing member 71 has a first widening portion 82 whose width is expanded toward the downstream side in the flow direction of the fuel gas 301 in a cross-sectional shape broken along the horizontal direction, and the first widening portion 82 Has a triangular prism shape. That is, the first wide portion 82 includes the first guide surface 82a, the second guide surface 82b, and the end surface 82c. The second flame stabilizing member 72 is integrally provided at the front end portion of the second flat portion 83 having a constant width and a front end portion of the second flat portion 83 in a sectional shape broken along the horizontal direction, and the width is a fuel gas A second widening portion 84 is formed to expand toward the downstream side in the flow direction of the line 301. The second flat portion 83 has a constant width along the flow direction of the fuel gas 301. The second widening portion 84 has a first guide surface 84 a and an end surface 84 c.

  The third flame holding member 73 has a third widened portion 86 whose width increases toward the downstream side in the flow direction of the fuel gas 301 along the horizontal direction, and the third widened portion 86 has a triangular prism shape. There is. That is, the third widening portion 86 has a horizontal cross section in the form of a substantially isosceles triangle, and is inclined to the first guide surface 86 a that is inclined toward the one first flame stabilizing member 71 and to the other first flame stabilizing member 71. And an end surface 86c on the front end side.

  As described above, in the combustion burner of the present embodiment, a plurality of first flame stabilizing members 71 are provided at predetermined intervals in the horizontal direction, and the second flame stabilizing members 72 are provided with fuel from the first flame stabilizing members 71. The third flame stabilizing member 73 is disposed between the plurality of first flame stabilizing members 71 and provided at predetermined intervals on both sides of the inner wall surface 61 a of the nozzle 61, and the third flame stabilizing member 73 includes fuel gas 301. Only the third widening portion 86 which widens toward the downstream side in the flow direction.

  Accordingly, a plurality of first flame holding members 71, second flame holding members 72, and third flame holding members 73 are alternately provided at predetermined intervals, and the flat portion of the third flame holding member 73 disposed in the center is eliminated. By using only the third widened portion 86, the worker can access the flame holder 64A from the central portion through the work space portion from the base end side of the fuel nozzle 61, and clean the flame holder 64A. Maintenance work such as repair and replacement can be easily performed.

  FIG. 4 is a horizontal sectional view showing a combustion burner according to another embodiment. The members having the same functions as those in the above-described embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

  As shown in FIG. 4, the combustion burner 21 </ b> B includes a fuel nozzle 61, a combustion air nozzle 62, and a secondary air nozzle 63 provided from the center side, and a flame holder 64 </ b> B provided in the fuel nozzle 61. There is.

  The flame holder 64 </ b> B includes two first flame holding members 71, two second flame holding members 72, and one third flame holding member 73. The first flame stabilizing member 71, the second flame stabilizing member 72, and the third flame stabilizing member 73 are disposed along the flow direction of the fuel gas 301 and along the vertical direction, and at predetermined intervals in the horizontal direction. It is arranged.

  The first flame holding member 71 is a tip portion of the fuel nozzle 61, on both sides in the radial direction with respect to the center line O along the jet direction of the fuel gas 301, and at a predetermined interval from the inner wall surface 61 a of the fuel nozzle 61. It is arranged with a gap. The second flame stabilizing member 72 is a tip end portion of the fuel nozzle 61 and is disposed at a predetermined interval on both sides of each first flame stabilizing member 71 in the horizontal direction. It is arrange | positioned at predetermined intervals from the wall surface 61a. The third flame stabilizing member 73 is a tip end portion of the fuel nozzle 61, and is disposed on the center line O along the ejection direction of the fuel gas 301 and at a predetermined interval from the respective first flame stabilizing members 71. There is.

  The first flame holding member 71 has a first flat portion 81 having a constant width and a first flat portion 81 integrally provided at a front end portion of the first flat portion 81 in a cross-sectional shape broken along the horizontal direction. And a widened portion 82. The first flat portion 81 has a constant width along the flow direction of the fuel gas 301. The width of the first widening portion 82 increases in the flow direction of the fuel gas 301. The first widening portion 82 has a horizontal cross section in a substantially isosceles triangle shape, the base end portion is connected to the first flat portion 81, and the tip end portion is wide toward the downstream side in the flow direction of the fuel gas 301 The front end is a plane perpendicular to the flow direction of the fuel gas 301. That is, the first wide portion 82 has a first guide surface 82a inclined inward in the width direction, a second guide surface 82b inclined outward in the width direction, and an end surface 82c on the front end side.

  The second flame holding member 72 has a second widened portion 84 having a cross-sectional shape broken along the horizontal direction and having a width that expands toward the downstream side in the flow direction of the fuel gas 301. Has a triangular prism shape. That is, the second widening portion 84 has a first guide surface 84a whose horizontal cross section has a substantially isosceles triangle shape and is inclined inward in the width direction, and an end surface 84c orthogonal to the flow direction of the fuel gas 301 on the front end side. There is no guide surface on the outer side in the width direction, and it is a plane along the flow direction of the fuel gas 301.

  The third flame holding member 73 has a third widened portion 86 having a cross-sectional shape broken along the horizontal direction and having a width that expands toward the downstream side in the flow direction of the fuel gas 301. Has a triangular prism shape. That is, the third widening portion 86 has a horizontal cross section in the form of a substantially isosceles triangle, and is inclined to the first guide surface 86 a that is inclined toward the one first flame stabilizing member 71 and to the other first flame stabilizing member 71. And an end surface 86c on the front end side.

  Thus, in the combustion burner of this embodiment, the 1st flame holding member 71 has the 1st flat part 81 and the 1st widening part 82, and the 2nd flame holding member 72 is the 2nd widening part. It has only 84.

  Therefore, by eliminating the flat portion of the second flame holding member 72 provided on the downstream side in the ejection direction of the fuel gas 301 and using only the second widened portion 84, a working space portion can be secured in the fuel nozzle. . Therefore, the maintenance worker can access the flame holder 64B from the base end side of the fuel nozzle 61 through the working space, facilitating maintenance work such as cleaning, repair and replacement of the flame holder 64B. It can be implemented.

  In the above-described embodiment, the flat portion of the first flame stabilizing member 71 is eliminated and only the first widening portion 82 is used. In another embodiment, the first flame stabilizing member 71 and the third flame stabilizing member are used. In the configuration in which the flat portion of 73 is eliminated and only the second and third widening portions 84 and 86 are provided, and in the other embodiment, the flat portions of the second flame stabilizing member 72 and the third flame stabilizing member 73 are eliminated and the widening portion Although the configurations having only 84 and 86 are shown, the present invention is not limited to these configurations. For example, the first flame stabilizing member 71 and the second flame stabilizing member 72 may be formed of a flat portion and a widening portion, and the flat portion of the third flame stabilizing member 73 may be eliminated to form only the widening portion.

  In the embodiment described above, the flat portion of any of the first flame stabilizing member 71, the second flame stabilizing member 72, and the third flame stabilizing member 73 is eliminated and only the widening portion is provided. Alternatively, all the flat portions of the second flame holding member 72 and the third flame holding member 73 may be eliminated and only the widened portion may be provided. That is, the first flame stabilizing member 71 has only the first widening portion 82 which widens toward the downstream side of the flow direction of the fuel gas 301, and the second flame stabilizing member 72 is downstream of the flow direction of the fuel gas 301 The third flame stabilizing member 73 has only the third widening portion 86 widening toward the downstream side in the flow direction of the fuel gas 301. Therefore, the worker can access the flame holder 64 from the base end side of the fuel nozzle 61 through the large working space, and facilitates maintenance work such as cleaning, repair, and replacement of the flame holder 64. It can be implemented.

  In the above-described embodiment, two first flame holding members 71, two second flame holding members 72, and one third flame holding member 73 are provided as the flame holders 64, 64A, 64B. However, it is not limited to this configuration. For example, the flame holder may be composed of two first flame holding members and two second flame holding members, or the flame holder may be composed of two first flame holding members and one third flame holding member. It may be configured. Further, the number of first flame stabilizing members is not limited to one or two, and three or more may be provided.

  Further, in the embodiment described above, the fuel nozzle 61, the combustion air nozzle 62, and the secondary air nozzle 63 are rectangular, but the present invention is not limited to this shape, and may be circular.

  In the embodiment described above, the first flame stabilizing member 71, the second flame stabilizing member 72, and the third flame stabilizing member 73 are disposed along the flow direction of the fuel gas 301 and along the vertical direction. The flame holding member 71, the second flame holding member 72, and the third flame holding member 73 may be arranged along the horizontal direction as well as along the flow direction of the fuel gas 301.

  In the above-described embodiment, the boiler of the present invention is a coal-fired boiler, but as the solid fuel, a boiler using biomass, petroleum coke, petroleum residue or the like may be used. Moreover, it can be used not only for solid fuel as fuel but for oil-fired boilers, such as heavy oil. Furthermore, it can be applied to mixed burning of these fuels.

21, 21A, 21B Combustion burner 61 Fuel nozzle 61a Inner wall surface 61b, 62b, 63e Opening (jet opening)
62 combustion air nozzle 63 secondary air nozzle 64, 64A, 64B flame holder 71 1st flame holding member 72 2nd flame holding member 73 3rd flame holding member 81 1st flat part 82 1st widening part 82a, 84a, 86a first guide surface 82b, 86b second guide surface 82c, 84c, 86c end surface 83 second flat portion 84 second wide portion 85 third flat portion 86 third wide portion 87, 88 support member P1 fuel gas flow path P11 1 Fuel gas passage P12 Second fuel gas passage P13 Third fuel gas passage P2 Combustion air passage P3 Secondary air passage

Claims (8)

A fuel nozzle that ejects a fuel gas that is a mixture of fuel and air;
A combustion air nozzle that ejects air from the outside of the fuel nozzle;
A first flame-holding member disposed upstream of the ejection opening of the fuel nozzle in the ejection direction of the fuel gas to widen the ejection direction of the fuel gas;
A second flame-holding member disposed downstream of the first flame-holding member in the ejection direction of the fuel gas and adjacent to the first flame-holding member to widen the ejection direction of the fuel gas;
With
At least one of the first flame stabilizing member and the second flame stabilizing member has only a widening portion that widens toward the downstream side in the flow direction of the fuel gas.
A combustion burner characterized by The first flame stabilizing member has only a first widening portion that widens toward the downstream side in the flow direction of the fuel gas,
The second flame stabilizing member includes a second widening portion which widens toward the downstream side in the flow direction of the fuel gas, and a second flat portion connected to the upstream side in the flow direction of the fuel gas from the second widening portion. The combustion burner according to claim 1, comprising: The first flame stabilizing member includes a first widening portion that widens toward the downstream side in the flow direction of the fuel gas, and a first flat portion connected to the upstream side in the flow direction of the fuel gas from the first widening portion Have
The combustion burner according to claim 1, wherein the second flame stabilizing member has only a second widening portion which widens toward the downstream side in the flow direction of the fuel gas. A plurality of the first flame stabilizing members are provided at predetermined intervals in the horizontal direction or the vertical direction, and the second flame stabilizing members are disposed at predetermined intervals on both sides of the first flame stabilizing member on the inner wall surface side of the fuel nozzle. And a third flame stabilizing member is disposed between the plurality of first flame stabilizing members,
The combustion burner according to claim 2 or 3, wherein the third flame stabilizing member includes only a third widening portion that widens toward the downstream side in the flow direction of the fuel gas. The first flame stabilizing member has only a first widening portion that widens toward the downstream side in the flow direction of the fuel gas,
The combustion burner according to claim 1, wherein the second flame stabilizing member has only a second widening portion which widens toward the downstream side in the flow direction of the fuel gas.   The second flame holding member is disposed on both sides in the widening direction of the first flame holding member, and the first flame holding member is provided with the first widening portion that widens the fuel gas ejection direction in two directions. The second flame holding member disposed on the inner wall surface side of the fuel nozzle is provided with the second widening portion that widens the fuel gas ejection direction only on the axial center side of the fuel nozzle. The combustion burner according to any one of claims 2 to 5. A plurality of combustion burners according to any one of claims 1 to 6 are disposed circumferentially at predetermined intervals to form a flame swirl flow.
A combustion apparatus characterized by A furnace having a hollow shape and installed along the vertical direction,
A combustion device according to claim 7;
A boiler comprising:

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