JP3204014U - Burning burner - Google Patents

Abstract

In a combustion burner using a fuel containing solids, durability is increased. SOLUTION: A fuel gas in which solid fuel and air are mixed can be blown, a fuel nozzle 51 connected to a fuel supply pipe 26 for supplying the fuel, and a combustion burner capable of blowing air from the outside of the fuel nozzle An air nozzle 52 and at least one flame holder 54 provided on the axial center side in the vicinity of the tip of the fuel nozzle are provided, and the fuel nozzle 51 has a wear-resistant member disposed on the entire inner peripheral surface. [Selection] Figure 4

Description

  The present invention relates to a combustion burner applied to a boiler for generating steam for power generation or factory use.

  For example, a conventional pulverized coal fired boiler has a furnace having a hollow shape and installed in the vertical direction, and a plurality of combustion burners are disposed on the furnace wall along the circumferential direction, and a plurality of combustion burners are provided in the vertical direction. It is arranged over the steps. This combustion burner is supplied with a mixture of pulverized coal (fuel) obtained by pulverizing coal and primary air (air), and also supplied with high-temperature combustion burner air (Coal secondary air). A flame is formed by blowing air for the combustion burner into the furnace, and combustion is possible in the furnace. This furnace has a flue connected to the top, and this flue is provided with a superheater, reheater, economizer, etc. for recovering the heat of exhaust gas, and it was generated by combustion in the furnace. Heat exchange is performed between the exhaust gas and water, and steam can be generated.

  Here, in the combustion burner of the pulverized coal-fired boiler, since the fuel is solid, the fuel comes into contact with members disposed in the region where the fuel flows. For this reason, there is a risk of wear in the fuel passage and the like. On the other hand, Patent Document 1 describes that a passage and a rectifying plate disposed inside are formed of high-chromium steel and are lined with a hard material such as ceramics or cermet.

JP 2005-265354 A

  This invention solves the subject mentioned above, and aims at providing the combustion burner which can make durability high.

  In order to achieve the above object, a combustion burner according to the present invention is capable of injecting a fuel gas in which solid fuel and air are mixed, a fuel nozzle connected to a fuel supply pipe for supplying the fuel, An air nozzle for a combustion burner capable of blowing air from the outside, and at least one flame holder provided on the axial center side in the vicinity of the tip of the fuel nozzle, the fuel nozzle being resistant to the entire inner peripheral surface. A wear member is arranged.

  The combustion burner includes a portion that is easily worn by solid fuel by disposing an abrasion-resistant member on the entire surface of the fuel nozzle, can protect the entire surface of the fuel nozzle, and can increase durability. In addition, by arranging wear-resistant members on the entire surface of the fuel nozzle, it is possible to increase wear resistance in areas where fuel behavior is unstable, and to prevent partial wear due to fuel behavior. , Durability can be increased. And the durability can improve, and the frequency of maintenance can be reduced.

  The flame holder is disposed in the vicinity of the tip of the fuel nozzle, and has a shape that increases in width toward the tip of the fuel nozzle. The flame holder has a wear-resistant member on a surface that becomes wider. It is preferable that they are arranged. Durability can be increased by disposing a wear-resistant member on the flame holder.

  The flame stabilizer has a plate-shaped rectifying plate disposed on an extension line on the downstream side in the fuel gas flow direction, and the rectifying plate is disposed over the entire surface along the fuel gas flow direction. It is preferable that an abrasion-resistant member is disposed. Durability can be increased by arranging a wear-resistant member on the current plate.

  Moreover, it is preferable that the said baffle plate is spaced apart from the said flame holder in the flow direction of the said fuel gas. By making the flame holder and the current plate separate, each component can be exchanged separately. This can simplify maintenance.

  In addition, the flame holder includes two first flame holding members that are parallel with a predetermined gap in the vertical direction along the horizontal direction and two second flame holding members that are parallel with the predetermined gap in the horizontal direction along the vertical direction. It is preferable that the flame member is arranged so as to intersect. Thereby, a flame can be formed appropriately.

  According to the present invention, by disposing the wear-resistant member on the entire surface of the fuel nozzle, it is possible to protect the entire surface of the fuel nozzle including the portion that is easily worn by the solid fuel, and to increase the durability.

FIG. 1 is a schematic configuration diagram showing a pulverized coal burning boiler to which a combustion burner according to the present embodiment is applied. FIG. 2 is a plan view showing a combustion burner in the pulverized coal burning boiler of the present embodiment. FIG. 3 is a front view showing the combustion burner of the present embodiment. FIG. 4 is a cross-sectional view taken along line AA showing the combustion burner of the present embodiment. FIG. 5 is a cross-sectional view taken along the line BB showing the combustion burner of the present embodiment. FIG. 6 is a schematic diagram illustrating a schematic configuration of the flame holding member and the current plate. FIG. 7 is a schematic diagram showing a schematic configuration of the fuel nozzle.

  Exemplary embodiments of a combustion burner according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment, Moreover, when there exist multiple embodiment, what comprises combining each embodiment is also included.

  FIG. 1 is a schematic configuration diagram showing a pulverized coal burning boiler to which a combustion burner according to the present embodiment is applied. FIG. 2 is a plan view showing a combustion burner in the pulverized coal burning boiler of the present embodiment. FIG. 3 is a front view showing the combustion burner of the present embodiment. FIG. 4 is a cross-sectional view taken along line AA showing the combustion burner of the present embodiment. FIG. 5 is a cross-sectional view taken along the line BB showing the combustion burner of the present embodiment. FIG. 6 is a schematic diagram illustrating a schematic configuration of the flame holding member and the current plate. FIG. 7 is a schematic diagram showing a schematic configuration of the fuel nozzle.

  The pulverized coal fired boiler to which the combustion burner of this embodiment is applied can use the pulverized coal obtained by pulverizing coal as a solid fuel, burn the pulverized coal with the combustion burner, and recover the heat generated by the combustion. Boiler.

  In this embodiment, as shown in FIG. 1, the pulverized coal burning boiler 10 is a conventional boiler, and includes a furnace 11, a combustion device 12, and a flue 13. The furnace 11 has a rectangular hollow shape and is installed along the vertical direction. A combustion device 12 is provided at the lower part of the furnace wall constituting the furnace 11.

  The combustion device 12 has a plurality of combustion burners 21, 22, 23, 24, 25 mounted on the furnace wall. In this embodiment, the combustion burners 21, 22, 23, 24, and 25 are arranged as four sets at equal intervals along the circumferential direction, and five sets along the vertical direction. Five stages are arranged.

  Each combustion burner 21, 22, 23, 24, 25 is connected to a pulverized coal machine (mill) 31, 32, 33, 34, 35 via a pulverized coal supply pipe 26, 27, 28, 29, 30. ing. Although not shown, the pulverized coal machines 31, 32, 33, 34, and 35 are supported in a housing so that the pulverization table can be driven to rotate with a rotation axis along the vertical direction, and face the upper side of the pulverization table. A plurality of crushing rollers are configured to be rotatably supported in conjunction with the rotation of the crushing table. Therefore, when coal is introduced between a plurality of pulverization rollers and a pulverization table, the pulverized coal supplied to the pulverized coal supply pipes 26, 27, and 28 is pulverized to a predetermined size and classified by carrier air (air). , 29, 30 are supplied to the combustion burners 21, 22, 23, 24, 25.

  Further, the furnace 11 is provided with a wind box 36 at the mounting position of each combustion burner 21, 22, 23, 24, 25, and one end portion of an air duct 37 is connected to the wind box 36, and this air The duct 37 has a blower 38 attached to the other end. Further, the furnace 11 is provided with an additional air nozzle 39 above the mounting position of each combustion burner 21, 22, 23, 24, 25. A branched air duct 40 branched from the air duct 37 to the additional air nozzle 39. The ends of are connected. Accordingly, the combustion air (combustion burner air (fuel gas combustion air), secondary air) sent by the blower 38 is supplied from the air duct 37 to the wind box 36, and each combustion burner 21 is supplied from the wind box 36. , 22, 23, 24, 25, and combustion air (additional air) sent by the blower 38 can be supplied from the branch air duct 40 to the additional air nozzle 39.

  Therefore, in the combustion apparatus 12, each combustion burner 21, 22, 23, 24, 25 can inject a pulverized fuel mixture (fuel gas) obtained by mixing pulverized coal and air into the furnace 11 and burn it. Burner air and secondary air can be blown into the furnace 11, and a flame can be formed by igniting the pulverized fuel mixture with an ignition torch (not shown).

  In general, when the boiler is started, each combustion burner 21, 22, 23, 24, 25 injects oil fuel into the furnace 11 to form a flame. Or after forming a flame with the starting oil burning burner, the air for combustion burners is supplied from this oil burning burner at the time of normal operation.

  The furnace 11 has a flue 13 connected to the upper part thereof, and superheaters (superheaters) 41 and 42 for recovering heat of exhaust gas as a convection heat transfer section and reheaters 43 and 44 in the flue 13. The economizers 45, 46 and 47 are provided, and heat exchange is performed between the exhaust gas generated by the combustion in the furnace 11 and water.

  The flue 13 is connected to an exhaust gas pipe 48 through which exhaust gas subjected to heat exchange is discharged downstream. This exhaust gas pipe 48 is provided with an air heater 49 between the air duct 37 and performs heat exchange between the air flowing through the air duct 37 and the exhaust gas flowing through the exhaust gas pipe 48, and the combustion burners 21, 22, 23, The temperature of the combustion air supplied to 24 and 25 can be raised.

  Although not shown, the exhaust gas pipe 48 is provided with a denitration device, an electrostatic precipitator, an induction blower, and a desulfurization device, and a chimney is provided at the downstream end.

  Accordingly, when the pulverized coal machines 31, 32, 33, 34, and 35 are driven, the generated pulverized coal together with the conveying air passes through the pulverized coal supply pipes 26, 27, 28, 29, and 30 and the combustion burners 21, 22, 23, 24, 25. The heated combustion air is supplied from the air duct 37 to the combustion burners 21, 22, 23, 24, 25 via the wind box 36, and is supplied from the branch air duct 40 to the additional air nozzle 39. . Then, the combustion burners 21, 22, 23, 24, and 25 blow the pulverized fuel mixture mixed with the pulverized coal and the carrier air into the furnace 11 and blow the combustion air into the furnace 11 and ignite at this time. Can form a flame. Further, the additional air nozzle 39 can perform combustion control by blowing additional air into the furnace 11. In the furnace 11, the pulverized fuel mixture and the combustion air are burned to generate a flame. When a flame is generated in the lower part of the furnace 11, the combustion gas (exhaust gas) rises in the furnace 11, and the flue 13 is discharged.

  That is, the combustion burners 21, 22, 23, 24, and 25 are combusted by injecting pulverized coal mixture and combustion air (combustion burner air / secondary air) into the combustion region in the furnace 11 and igniting at this time. A flame swirl is formed in the region. This flame swirl rises while swirling and reaches the reduction region. The additional air nozzle 39 blows additional air above the reduction region in the furnace 11. In the furnace 11, the interior is maintained in a reducing atmosphere by setting the air supply amount to be less than the theoretical air amount with respect to the pulverized coal supply amount. The NOx generated by the combustion of the pulverized coal is reduced in the furnace 11, and then additional air (additional air) is supplied to complete the oxidation combustion of the pulverized coal, and the amount of NOx generated by the combustion of the pulverized coal is reduced. Reduced.

  At this time, while water supplied from a water supply pump (not shown) is preheated by the economizers 45, 46 and 47, it is supplied to a steam drum (not shown) and supplied to each water pipe (not shown) on the furnace wall. Is heated to become saturated steam and fed into a steam drum (not shown). Further, saturated steam of a steam drum (not shown) is introduced into the superheaters 41 and 42 and is heated by the combustion gas. The superheated steam generated by the superheaters 41 and 42 is supplied to a power plant (not shown) such as a turbine. Further, the steam taken out in the middle of the expansion process in the turbine is introduced into the reheaters 43 and 44, overheated again, and returned to the turbine. In addition, although the furnace 11 was demonstrated as a drum type | mold (steam drum), it is not limited to this structure.

  Thereafter, the exhaust gas that has passed through the economizers 45, 46, and 47 of the flue 13 is subjected to removal of harmful substances such as NOx by a catalyst in a denitration device (not shown) in the exhaust gas pipe 48, and the particulate matter is collected by an electric dust collector. Is removed, and after the sulfur content is removed by the desulfurizer, it is discharged from the chimney into the atmosphere.

  Here, although the combustion apparatus 12 is demonstrated in detail, since each combustion burner 21, 22, 23, 24, 25 which comprises this combustion apparatus 12 has comprised the substantially the same structure, it is located in the uppermost stage. Only the combustion burner 21 will be described.

  As shown in FIG. 2, the combustion burner 21 includes combustion burners 21 a, 21 b, 21 c, and 21 d provided on four wall surfaces in the furnace 11. Each combustion burner 21a, 21b, 21c, 21d is connected to each branch pipe 26a, 26b, 26c, 26d branched from the pulverized coal supply pipe 26, and each branch pipe 37a, 37b, 37c branched from the air duct 37. , 37d are connected.

  Therefore, each combustion burner 21a, 21b, 21c, 21d on each wall surface of the furnace 11 blows into the furnace 11 a pulverized fuel mixture in which pulverized coal and carrier air are mixed, and the pulverized fuel mixture Blow combustion air to the outside. Then, by igniting the pulverized fuel mixture from each combustion burner 21a, 21b, 21c, 21d, four flames F1, F2, F3, F4 can be formed, and this flame F1, F2, F3, F4. Is a flame swirl flow swirling counterclockwise as viewed from above the furnace 11 (in FIG. 2).

  In the combustion burner 21 (21a, 21b, 21c, 21d) configured as described above, as shown in FIGS. 3, 4, and 5, a fuel nozzle 51, a combustion burner air nozzle 52, and a combustion burner air nozzle 52 from the center side, A secondary air nozzle 53 is provided, and a flame holder 54 and a rectifier 55 are provided. The fuel nozzle 51 is capable of blowing a fuel gas (a fine fuel mixture, air) obtained by mixing pulverized coal (solid fuel) and carrier air (air, primary air). The fuel nozzle 51 protrudes from the wind box 36 at the outer end of the furnace 11 and is connected to the pulverized coal supply pipes 26, 27, 28, 29, and 30. The combustion burner air nozzle (combustion air nozzle) 52 is disposed outside the fuel nozzle 51, and combustion air (combustion burner air, fuel gas combustion air) is disposed on the outer peripheral side of the fuel gas injected from the fuel nozzle 51. Coal secondary air) can be blown in. The secondary air nozzle 53 is located outside the combustion burner air nozzle 52 and above the combustion burner air nozzle 52 in the vertical direction, outside the combustion burner air nozzle 52, and at the combustion burner air nozzle 52. It is arranged at a position on the lower side in the vertical direction. In this case, the vertical direction includes a direction shifted by a minute angle with respect to the vertical direction. The secondary air nozzle 53 is not disposed outside the combustion burner air nozzle 52 and at a position adjacent in the horizontal direction. The secondary air nozzle 53 can inject secondary air (AUX) into the outer peripheral side of the combustion burner air injected from the combustion burner air nozzle 52. The secondary air nozzle 53 may be disposed outside the combustion burner air nozzle 52 and at a position adjacent in the horizontal direction. Further, the secondary air nozzle 53 may be disposed outside the combustion burner air nozzle 52 and at a position adjacent in the horizontal direction, and not disposed at a position adjacent in the vertical direction. The secondary air nozzle 53 may be provided on the entire outer periphery of the combustion burner air nozzle 52. The secondary air nozzle 53 may be capable of adjusting the ejection amount of the secondary air by providing a damper opening adjustment mechanism or the like.

  It has a fuel nozzle 51 of the combustion burner 21, a combustion burner air nozzle 52, a tilt part 80, and a pipe line part 82 slidably connected to the tilt part 80. The tilt portion 80 is the tip of the fuel nozzle 51 of the combustion burner 21 and the air nozzle 52 for the combustion burner, and is supported so as to be movable in a set direction with respect to the pipe line portion 82. The direction in which the tilt unit 80 is movable is not particularly limited, and may be movable in the axial direction (vertical direction) of the furnace 11 or may be movable in the cross-sectional direction (horizontal direction) of the furnace 11. The combustion burner 21 adjusts the direction in which the pulverized fuel mixture in which the pulverized coal and the carrier air are mixed is adjusted by adjusting the direction of the tilt unit 80. Further, the tilt portion 80 includes a base portion 84 including a fulcrum that moves with respect to the conduit portion 82 and a distal end portion 86 that is a distal end side of the base portion 84, that is, an end portion inside the furnace. The distal end portion 86 is fixed to the base portion 84 with a fastening jig such as a screw. Note that the distal end portion 86 may be fixed by welding.

  The pipe section 82 is connected to the tilt section 80, and pipe lines corresponding to the fuel nozzle 51, the combustion burner air nozzle 52, and the secondary air nozzle 53 are formed. Fuel gas mixed with pulverized coal and air and combustion burner air are supplied. The pipe line part 82 has a long tubular structure. The combustion burner 21 may be provided with a tilt portion also in the secondary air nozzle 53 so that the fuel nozzle 51 and the combustion burner air nozzle 52 are integrally movable with respect to the conduit portion. The combustion burner 21 may have a structure that does not move the secondary air nozzle 53. In the present embodiment, the tilt portion 80 is provided. However, the tip portion for injecting the fuel gas and the combustion burner air may be fixed and may not move with respect to the conduit portion 82.

  In the fuel nozzle 51, the tip side portion, that is, the portion corresponding to the tilt portion 80 is a straight pipe, and the area (opening area) of the cross section (opening) orthogonal to the direction in which the pulverized fuel mixture is blown is constant. The combustion burner air nozzle 52 has a shape in which a portion on the tip side, that is, a portion corresponding to the tilt portion 80 is narrowed toward the tip, and has a cross section (opening) orthogonal to the direction in which the pulverized fuel mixture is blown. The area becomes smaller toward the tip. That is, the combustion burner air nozzle 52 has a shape in which the area of the surface surrounded by the outer surface becomes smaller with respect to the upstream end portion in the fuel gas flow direction toward the tip. The secondary air nozzle 53 has a shape in which a portion on the tip side, that is, a portion corresponding to the tilt portion 80 is narrowed toward the tip, and an area of a cross section (opening) perpendicular to the direction in which the pulverized fuel mixture is blown. Becomes smaller toward the tip.

  The shape of the opening of the fuel nozzle 51 and the combustion burner air nozzle 52 is not limited to a square, and may be a rectangle. In this case, the corner may have a curved shape. By using a tubular structure with a curved corner, the strength of the nozzle can be improved. Furthermore, it is good also as a cylinder.

  The flame holder 54 is disposed in the fuel nozzle 51 at the downstream side in the fuel gas blowing direction and at the axial center side, thereby functioning for ignition of the fuel gas and flame holding. is there. The flame holder 54 is fixed to the distal end portion 86 of the tilt portion 80. This flame holder 54 is arranged so that the first flame holding members 61, 62 along the horizontal direction and the second flame holding members 63, 64, 65, 66 along the vertical direction (vertical direction) form a cross shape. Thus, a so-called double cross split structure is formed. Each of the first flame holding members 61 and 62 and the second flame holding members 63, 64, 65, and 66 has a widened shape in which the width becomes wider toward the downstream side in the fuel gas flow direction. The first flame holding members 61, 62 and the second flame holding members 63, 64, 65, 66 of the present embodiment have an isosceles triangular cross section, and are wider toward the downstream side in the fuel gas flow direction. Therefore, the front end is a plane perpendicular to the flow direction of the fuel gas.

  The rectifier 55 is disposed in the fuel nozzle 51 and upstream of the flame holder 54 in the fuel gas flow direction. The rectifier 55 is fixed to the base 84 of the tilt unit 80. The rectifying unit 55 is disposed away from the flame holder 54 in the fuel gas flow direction. The rectifier 55 rectifies the flow of the fuel gas flowing through the fuel nozzle 51. The rectifier 55 includes first rectifying plates 71 and 72 along the horizontal direction, and second rectifying plates 73, 74, 75, and 76 along the vertical direction (vertical direction).

  The first rectifying plates 71 and 72 and the second rectifying plates 73, 74, 75, and 76 basically have a plate shape with a constant thickness. The first rectifying plates 71 and 72 and the second rectifying plates 73, 74, 75, and 76 are arranged in a cross shape. The first rectifying plate 71 is disposed at a position overlapping the extension line of the first flame holding member 61 in the fuel gas flow direction. Similarly, the 1st baffle plate 72 is arrange | positioned in the position which overlaps with the extension line of the 1st flame holding member 62 in the flow direction of fuel gas. Similarly, the 2nd baffle plate 73 is arrange | positioned in the position which overlaps with the extended line of the 2nd flame holding member 63 in the flow direction of fuel gas. Similarly, the 2nd baffle plate 74 is arrange | positioned in the position which overlaps with the extended line of the 2nd flame holding member 64 in the flow direction of fuel gas. Similarly, the 2nd baffle plate 75 is arrange | positioned in the position which overlaps with the extended line of the 2nd flame holding member 65 in the flow direction of fuel gas. Similarly, the 2nd baffle plate 76 is arrange | positioned in the position which overlaps with the extended line of the 2nd flame holding member 66 in the flow direction of fuel gas.

  Next, the structure of the flame holder 54, the rectifier 55, and the fuel nozzle 51 will be described with reference to FIGS. 6 and 7 in addition to FIGS. Although FIG. 6 demonstrates the 1st flame holding member 61 and the 1st current plate 71 among the flame holder 54 and the rectifier 55, the other flame holding members and the current plate also have the same structure. As shown in FIG. 6, the first flame holding member 61 and the first rectifying plate 71 are provided with wear-resistant members on the surfaces. The first flame holding member 61 includes a base material 92 and a wear-resistant member 94 disposed on the surface of the base material 92. The base material 92 has an isosceles triangular shape and has symmetrical sides (surfaces) 93 of an isosceles triangle that is a surface to be widened. The wear resistant member 94 is disposed over the entire side 93. The first rectifying plate 71 includes a base material 102 and a wear-resistant member 104 disposed on the surface of the base material 102. The base material 102 is a plate member, and the upstream end 105 in the fuel gas flow direction has a triangular shape that protrudes upstream. That is, the end portion 105 has a shape that becomes narrower toward the upstream side. The wear resistant member 104 is disposed on the entire surface 103 of the base material 102 along the exhaust gas flow direction, that is, the entire surface having the largest area. Further, the wear-resistant member 104 is disposed over the entire end portion 105.

  Next, in the fuel nozzle 51, the wear resistant member 106 is disposed on the entire inner peripheral surface through which the fuel gas passes. Specifically, the fuel nozzle 51 is connected to the pulverized coal supply pipe 26 from the upstream end in the flow direction of the fuel gas, and downstream in the flow direction of the fuel gas in which the flame stabilizer 54 is provided. The wear-resistant member 106 is disposed on the entire surface up to the end.

  The base materials 92 and 102 can be formed of, for example, a metal mainly composed of iron such as SUS. The wear resistant members 94, 104, 106 are materials having higher wear resistance than the base materials 92, 102, and ceramics, high chromium steel, a composite material in which a ceramic is embedded in a metal, or the like can be used. When the wear-resistant members 94, 104, 106 are made of, for example, ceramics, they can be arranged on the surfaces of the base materials 92, 102 by attaching and fixing a ceramic plate material on the surfaces of the base materials 92, 102. Further, when the wear-resistant members 94 and 104 are made of, for example, high chromium steel, the plate-like high chromium steel is electrodeposited on the base materials 92 and 102 or fixed by welding to be arranged on the surfaces of the base materials 92 and 102. can do.

  The fuel nozzle 51 and the combustion burner air nozzle 52 have a long tubular structure, the fuel nozzle 51 is a rectangular opening, and the combustion burner air nozzle 52 is a rectangular ring-shaped opening. . Therefore, the fuel nozzle 51 and the combustion burner air nozzle 52 have a double pipe structure. Secondary air nozzles 53 are arranged above and below the fuel nozzle 51 and the combustion burner air nozzle 52 in the vertical direction. As a result, the combustion burner air nozzle 52 is disposed outside the opening 51 a of the fuel nozzle 51, and the secondary air nozzle 53 is disposed outside the combustion burner air nozzle 52.

  These nozzles 51, 52, and 53 are arranged such that the opening 51a is aligned on the same plane. The flame holder 54 is supported by a plate material (not shown) from the inner wall surface of the fuel nozzle 51 or the upstream side of the flow path through which the fuel gas flows. Further, the fuel nozzle 51 includes therein first flame holding members 61 and 62 as the flame holder 54, second flame holding members 63, 64, 65 and 66, and first flow straightening plates 71 and 72 as the rectifier 55, Since the second rectifying plates 73, 74, 75, and 76 are arranged, the fuel gas flow path is divided into fifteen. The flame holder 54 has a widened shape whose width increases toward the front end, and the front end face is aligned on the same plane as the opening 51a. The rectifier 55 has a plate shape and extends in a direction along the tilt portion 80.

  Therefore, in this combustion burner 21, fuel gas in which pulverized coal and air are mixed is blown into the furnace from the fuel nozzle 51, and combustion burner air is blown into the furnace from the combustion burner air nozzle 52 on the outside thereof. On the outside, secondary air is blown into the furnace from the secondary air nozzle 53. The fuel gas flowing through the fuel nozzle 51 is rectified into a flow in a direction along the angle of the tilt unit 80 by the rectifier 55. The fuel gas rectified by the rectifier 55 and blown into the furnace is branched by the flame holder 54 at the opening 51a of the fuel nozzle 51, ignited, and burned to become combustion gas. Moreover, combustion of fuel gas is accelerated | stimulated because the air for combustion burners is blown into the outer periphery of this fuel gas. In addition, since the secondary air is blown into the outer periphery of the combustion flame, the ratio of the combustion burner air and the secondary air can be adjusted to obtain optimum combustion.

  In the combustion burner 21, since the flame holder 54 has a split shape, the fuel gas is branched by the flame holder 54 at the opening 51 a of the fuel nozzle 51. At this time, the flame holder 54 is moved to the fuel nozzle 51. In the central region of the opening 51a, ignition and flame holding of the fuel gas are performed in this central region. Thereby, the internal flame holding of the combustion flame (flame holding in the central region of the opening 51a of the fuel nozzle 51) is realized.

  Therefore, compared with a configuration in which external flame holding of the combustion flame is performed, the outer peripheral portion of the combustion flame becomes low temperature, and oxygen is consumed from the inside of the flame, resulting in low oxygen. The temperature of the outer peripheral part of the combustion flame under a high oxygen atmosphere can be lowered, and the amount of NOx generated in the outer peripheral part of the combustion flame is reduced.

  Here, in the combustion burner 21, since the structure which carries out an internal flame is employ | adopted, it is preferable that fuel gas and combustion air (air for combustion burners, and secondary air) are supplied as a straight flow. That is, the fuel nozzle 51, the combustion burner air nozzle 52, and the secondary air nozzle 53 have a structure for supplying the fuel gas, the combustion burner air, and the secondary air as a straight flow in the burner axial direction without swirling. Is preferred. Since this fuel gas, combustion burner air, and secondary air are injected as a straight flow to form a combustion flame, gas circulation in the combustion flame is suppressed in the configuration in which the combustion flame is held inside. As a result, the outer periphery of the combustion flame is maintained at a low temperature, and the amount of NOx generated by mixing with the combustion burner air is reduced. From the above, the combustion burner 21 can reduce the flow velocity inside the fuel gas flow and realize a proper flow that can suppress ignition at the outer periphery by making the flow velocity outside the fuel gas flow substantially the same as the combustion burner air nozzle 52. it can. Thereby, the internal flame holding performance that causes ignition relatively early from the inside of the fuel gas can be improved, the high-temperature high-oxygen region at the boundary between the fuel gas and the combustion burner air can be suppressed, and NOx can be reduced. .

  Further, the combustion burner 21 includes a portion that is easily worn by solid fuel by disposing the wear-resistant member 106 on the entire surface of the fuel nozzle 51, so that the entire surface of the fuel nozzle can be protected, and durability is increased. Can do. Here, the pulverized coal as the fuel reaches the combustion burner 21 through the pulverized coal supply pipe 26 having a plurality of bends. Further, at the outlet of the pulverized coal supply pipe 26 by the bend of the pulverized coal supply pipe 26, that is, at the inlet of the combustion burner 51, a region having a high pulverized coal concentration is formed along the inner wall of the pipe line. For example, on the upstream side of the fuel burner, there is a portion where the amount of wear increases in part in the circumferential direction. Further, the position where the wear is likely to occur varies depending on the fuel supply state. On the other hand, the combustion burner 21 can arrange | position the abrasion-resistant member 106 in all the area | regions where countermeasures are required. As a result, by arranging the wear-resistant member on the entire surface of the fuel nozzle, it is possible to increase the wear resistance in the region where the fuel behavior is unstable, and to prevent a part of the fuel from being worn by the behavior of the fuel. And durability can be increased.

  The combustion burner 21 is provided with wear-resistant members 94 and 104 on the flame holder 54 and the rectifying plate 55 arranged inside the fuel nozzle 51, so that the solid content in the combustion gas is added to the flame holder 54 and the rectifying plate 55. It is possible to reduce surface wear when contacted. Further, the wear-resistant member 94 is provided on the surface 93 of the flame-holding member, and the wear-resistant member 104 is selectively disposed on the surfaces 103 and 105 of the rectifying plate 55. Can be arranged. Specifically, since the wear-resistant member 94 is widened, it is possible to suppress the wear of the surface 93 that is easily in contact with the solid content. The wear-resistant member 104 on the surface 103 can suppress wear on the surface 103 where solid content is likely to come into contact when the angle of the tilt portion 80 is inclined to the pipe line portion 82. The wear-resistant member 104 at the end portion 105 can suppress wear on the surface of the end portion 105 that is easily in contact with the solid content.

  Moreover, the combustion burner 21 of this embodiment can maintain the flame holder 54 and the current plate 55 separately by arranging the flame holder 54 and the current plate 55 apart from each other. That is, only the flame holder 54 can be replaced, and only the current plate 55 can be replaced. Thereby, the combustion burner 21 can selectively replace a portion that needs to be replaced, can reduce the number of portions to be replaced at the time of maintenance, and can facilitate maintenance. Since the part to be replaced can be reduced, the weight of the replacement part can also be reduced. In addition, since the combustion burner 21 has a tip 86 separate from the base 84, the flame holder 54 and the flow straightening plate 55 are separated from each other, so that the flame support fixed to the tip 86 and the tip 86 is provided. It is also possible to replace only the device 54 as a unit. Thereby, since only the front-end | tip part 86 can be replaced | exchanged, it can make maintenance easy.

  Moreover, the combustion burner 21 makes the arrangement area | region of the rectifying plate 55 smaller by arranging the flame holder 54 and the rectifying plate 55 apart from each other than when the flame holder 54 and the rectifying plate 55 are integrated. be able to. Thereby, the area | region which provides an abrasion-resistant member can be decreased.

  Here, the flame holder of the present embodiment has a triangular cross-sectional shape, but is not limited to this shape, and may have a quadrangular shape. Moreover, in the said embodiment, although the cross-sectional shape of the combustion burner 21 was made into the square, circular may be sufficient and another polygon may be sufficient.

  In addition, the combustion burner includes the first flame stabilizer 61 and the first rectifying plate 71, but may be configured to include only the first flame holder 61 without the first rectifying plate 71. By not providing the first rectifying plate 71, it is possible to reduce the number of parts subject to maintenance. The combustion burner may have a structure in which the first flame stabilizer 61 and the first rectifying plate 71 are connected.

  Here, in the combustion burner 21 of the present embodiment, the downstream end of the flame holder 54 is set to a position overlapping the downstream end of the fuel nozzle 51, that is, the opening 51a in the fuel gas flow direction. However, the present invention is not limited to this. The combustion burner 21 only needs to have the flame holder 54 disposed in the vicinity of the tip of the fuel nozzle 51. Here, the vicinity of the tip is inside the nozzle of the fuel burner 51. When the combustion burner 21 includes the tilt part 80 as in the present embodiment, it is preferable to dispose the flame holder 54 inside the tilt part 80.

  In the combustion burner 21 of the present embodiment, the wear-resistant member is provided on the two surfaces facing the flame-holding member and the current plate, but may be provided only on one surface. For example, when the tilt unit 80 does not move and the tilt unit 80 is tilted with respect to the pipe line part 82, the angle formed with the axis of the pipe line part 82 is smaller than 180 °. A wear-resistant member may be provided on the side surface.

  Although pulverized coal has been described as an example of combustion fuel, the present invention is not limited to pulverized coal (solid fuel), and may be any fuel containing solids, such as biomass, residue, petroleum coke, etc. Fuel or a mixture of two or more of these fuels may be used.

  Moreover, in each embodiment mentioned above, as the combustion apparatus 12, although each four combustion burners 21, 22, 23, 24, 25 provided in the wall surface of the furnace 11 were arrange | positioned and comprised along the perpendicular direction, it comprised, It is not limited to this configuration. That is, the combustion burner may be arranged at the corner without being arranged on the wall surface. The combustion apparatus is not limited to the swirl combustion method, and may be a front combustion method in which the combustion burner is disposed on one wall surface, or an opposed combustion method in which the combustion burner is disposed opposite to the two wall surfaces.

DESCRIPTION OF SYMBOLS 10 Pulverized coal fired boiler 11 Furnace 21, 22, 23, 24, 25 Combustion burner 51 Fuel nozzle 52 Combustion burner air nozzle 53 Secondary air nozzle 54 Flame holder 55 Current plate 61, 62, 63, 64, 65, 66 Flame holding member 80 Tilt part 82 Pipe line part

Claims (5)

A fuel nozzle capable of blowing a fuel gas mixed with solid fuel and air, connected to a fuel supply pipe for supplying the fuel; and
An air nozzle for a combustion burner capable of blowing air from the outside of the fuel nozzle;
And at least one flame holder provided on the axial center side in the vicinity of the tip of the fuel nozzle,
The fuel nozzle has a wear-resistant member disposed on the entire inner peripheral surface thereof. The flame holder is disposed in the vicinity of the tip of the fuel nozzle and has a shape that increases in width toward the tip of the fuel nozzle,
The combustion burner according to claim 1, wherein the flame holder is provided with a wear-resistant member on a surface having a wide width. A plate-shaped rectifying plate disposed on an extension line on the downstream side in the fuel gas flow direction of the flame holder,
3. The combustion burner according to claim 1, wherein a wear-resistant member is disposed on an entire surface of the rectifying plate along the flow direction of the fuel gas.   The combustion burner according to any one of claims 1 to 3, wherein the rectifying plate is separated from the flame holder in a flow direction of the fuel gas.   The flame holder includes two first flame holding members that are parallel with a predetermined gap in the vertical direction along the horizontal direction, and two second flame holding members that are parallel with the predetermined gap in the horizontal direction along the vertical direction. The combustion burner according to any one of claims 1 to 4, wherein the combustion burner is disposed so as to intersect with each other.

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