JP6058077B2 - Burning burner - Google Patents

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. The combustion burner is supplied with an air-fuel mixture of pulverized coal (fuel) obtained by pulverizing coal and primary air, and also supplied with high-temperature secondary air, and blows the air-fuel mixture and secondary air into the furnace. This forms a flame and can be burned in this 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.

  As a combustion burner of such a pulverized coal fired boiler, for example, there is one described in Patent Document 1 below. In the combustion apparatus described in Patent Document 1, by providing a flame holder between the center inside the pulverized coal injection hole (primary flow path) and the outer periphery, the pulverized coal concentrated flow collides with the flame holder. Thus, stable low NOx combustion is possible over a wide load range.

Japanese Patent Laid-Open No. 08-135919

  In the conventional combustion apparatus described above, when the combustion gas of pulverized coal and air collides with the flame holder, the flow is separated at the rear end of the flame holder, and the flame at the front end of the flame holder is retained. It will be difficult to fully demonstrate the flame ability. Then, there is a problem that ignition occurs outside the flame holder and NOx is generated.

  The present invention solves the above-described problems, and an object of the present invention is to provide a combustion burner that can achieve a proper flow of fuel gas in which solid fuel and air are mixed to reduce the amount of NOx generated. .

  In order to achieve the above object, a combustion burner according to the present invention comprises a fuel nozzle for supplying fuel gas into a furnace, a secondary air nozzle for supplying secondary air from the outside of the fuel nozzle, and the fuel nozzle. A flame holder provided on the downstream side in the fuel gas flow direction, and a guide member provided at a position facing the flame holder at the tip of the fuel nozzle.

  Therefore, the guide member is provided at the tip of the fuel nozzle so as to face the flame holder, so that the fuel gas flowing in the fuel nozzle is properly guided by the guide member, and the proper flow of the fuel gas is obtained. As a result, the internal flame holding performance can be improved, and the amount of NOx generated can be reduced.

  In the combustion burner of the present invention, the guide member guides the fuel gas to the axial center side of the fuel nozzle at the tip of the fuel nozzle.

  Therefore, the fuel gas is guided to the axial center side of the fuel nozzle by the guide member at the tip portion of the fuel nozzle, so that an appropriate flow of the fuel gas can be realized and the internal flame holding performance can be improved.

  In the combustion burner according to the present invention, the guide member guides the fuel gas in a direction away from the secondary air.

  Therefore, the guide member guides the fuel gas in a direction away from the secondary air, the mixing of the fuel gas and the secondary air is suppressed, and the outer periphery of the combustion flame is maintained at a low temperature. The amount of NOx generated by mixing the gas and the secondary air can be reduced.

  In the combustion burner of the present invention, the guide member is arranged along the inner wall surface of the fuel nozzle.

  Therefore, by arranging the guide member along the inner wall surface of the fuel nozzle, the fuel gas flowing through the fuel nozzle is effectively guided to the axial center side, thereby guiding the fuel gas in the direction away from the secondary air. be able to.

  In the combustion burner of the present invention, the guide member is arranged between the inner wall surface of the fuel nozzle and the flame holder.

  Therefore, by disposing the guide member between the inner wall surface of the fuel nozzle and the flame holder, the fuel gas flowing inside the fuel nozzle is effectively guided to the axial center side, so that the fuel gas is removed from the secondary air. It can be guided in the direction of separation.

  In the combustion burner of the present invention, the flame holder has a widened portion on the downstream side in the flow direction of the fuel gas, and the guide member is arranged to face the widened portion.

  Therefore, it is possible to ensure a sufficient flame holding function.

  In the combustion burner according to the present invention, the guide member has an inclined surface that guides the fuel gas toward the flame holder side at a downstream side in the flow direction of the fuel gas.

  Therefore, the fuel gas flowing through the fuel nozzle can be appropriately guided by the guide member.

  The combustion burner according to the present invention is characterized in that a plurality of flame holders are provided, and a plurality of the flow paths of the fuel gas are divided at the opening of the fuel nozzle.

  Therefore, an appropriate flow of the fuel gas can be realized, and the internal flame holding performance can be improved.

  According to the combustion burner of the present invention, since the guide member is provided at the tip of the fuel nozzle at a position facing the flame holder, an appropriate flow of the fuel gas can be realized, and as a result, the internal flame holding performance can be improved. Can be improved.

FIG. 1 is a front view illustrating a combustion burner according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view illustrating the combustion burner according to the first embodiment. FIG. 3 is a schematic configuration diagram illustrating a pulverized coal fired boiler to which the combustion burner of Example 1 is applied. FIG. 4 is a plan view illustrating a combustion burner in the pulverized coal burning boiler according to the first embodiment. FIG. 5 is a cross-sectional view illustrating a combustion burner according to a second embodiment of the present invention. FIG. 6 is a front view showing a combustion burner according to Embodiment 3 of the present invention. FIG. 7 is a front view showing a combustion burner according to Embodiment 4 of the present invention. FIG. 8 is a cross-sectional view illustrating a combustion burner according to a fifth embodiment of the present invention. FIG. 9 is a cross-sectional view illustrating a modification of the combustion burner according to the fifth embodiment.

  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 Example, Moreover, when there exists multiple Example, what comprises combining each Example is also included.

  FIG. 1 is a front view showing a combustion burner according to Embodiment 1 of the present invention, FIG. 2 is a cross-sectional view showing the combustion burner of Embodiment 1, and FIG. 3 is pulverized coal to which the combustion burner of Embodiment 1 is applied. FIG. 4 is a schematic configuration diagram showing a burning boiler, and FIG. 4 is a plan view showing a combustion burner in the pulverized coal burning boiler of the first embodiment.

  The pulverized coal fired boiler to which the combustion burner of Example 1 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 the first embodiment, as shown in FIG. 3, the pulverized coal burning boiler 10 is a conventional boiler and includes a furnace 11 and a combustion device 12. 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 5 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 crushing rollers and a crushing table, the pulverized coal supplied to the pulverized coal supply pipes 26 and 27 is pulverized to a predetermined size and classified by carrier air (primary air). , 28, 29, 30 can be 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. Accordingly, the combustion air (secondary air and tertiary air) sent by the blower 38 is supplied from the air duct 37 to the wind box 36, and the combustion burners 21, 22, 23, 24, 25 are supplied from the wind box 36. Can be supplied to.

  Therefore, in the combustion apparatus 12, each combustion burner 21, 22, 23, 24, 25 can blow a pulverized fuel mixture (fuel gas) obtained by mixing pulverized coal and primary air into the furnace 11. 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.

  The furnace 11 has a flue 40 connected to the upper portion thereof, and a superheater (superheater) 41 and 42 for recovering heat of exhaust gas as a convection heat transfer section, and a reheater 43 and 44 in the flue 40. 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 40 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. Also, heated combustion air is supplied from the air duct 37 to the combustion burners 21, 22, 23, 24, 25 via the wind box 36. 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. 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 40 is discharged.

  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. Then, NOx generated by the combustion of the pulverized coal is reduced in the furnace 11, and then additional air is supplied to complete the oxidation combustion of the pulverized coal, thereby reducing the amount of NOx generated by the combustion of the pulverized coal. .

  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 40 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. 4, the combustion burner 21 is composed of 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. 4).

  In the combustion burner 21 (21a, 21b, 21c, 21d) configured as described above, as shown in FIGS. 1 and 2, the fuel nozzle 51, the secondary air nozzle 52, and the tertiary air nozzle are arranged from the center side. 53 and a flame holder 54 are provided. The fuel nozzle 51 is capable of blowing a fuel gas (a fine fuel mixture) obtained by mixing pulverized coal (solid fuel) and carrier air (primary air). The secondary air nozzle 52 is disposed outside the fuel nozzle 51 and can blow combustion air (secondary air) into the outer peripheral side of the fuel gas injected from the fuel nozzle 51. The tertiary air nozzle 53 is disposed outside the secondary air nozzle 52 and can blow tertiary air into the outer peripheral side of the secondary air injected from the secondary air nozzle 52.

  Further, 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 fuel gas ignition and flame holding. Is. This flame holder 54 is a so-called so-called “flame shape” in which first flame holding members 61 and 62 along the horizontal direction and second flame holding members 63 and 64 along the vertical direction (vertical direction) are arranged in a cross shape. It has a double cross split structure. Each first flame holding member 61, 62 has a flat portion 61a, 62a having a flat plate shape and a front end portion (downstream end portion in the fuel gas flow direction) of the flat portions 61a, 62a. Are provided with widened portions 61b and 62b which are integrally provided. The widened portions 61b and 62b have an isosceles triangular cross section, the width increases toward the downstream side in the fuel gas flow direction, and the front end is a plane perpendicular to the fuel gas flow direction. Although not shown, the second flame holding members 63 and 64 have the same structure.

  Therefore, the fuel nozzle 51 and the secondary air nozzle 52 have a long tubular structure, the fuel nozzle 51 has a rectangular opening 51a, and the secondary air nozzle 52 has a rectangular ring-shaped opening. Since it has 52a, the fuel nozzle 51 and the secondary air nozzle 52 have a double tube structure. A tertiary air nozzle 53 is arranged as a double pipe structure outside the fuel nozzle 51 and the secondary air nozzle 52, and has a rectangular ring-shaped opening 53a. As a result, the opening 52a of the secondary air nozzle 52 is disposed outside the opening 51a of the fuel nozzle 51, and the opening 53a of the tertiary air nozzle 53 is disposed outside the opening 52a of the secondary air nozzle 52. It will be arranged. The tertiary air nozzle 53 may be a tertiary air nozzle by arranging a plurality of nozzles separately on the outer peripheral side of the secondary air nozzle 52 without being arranged as a double tube structure.

  These nozzles 51, 52, 53 are arranged such that the openings 51a, 52a, 53a are 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, since the fuel nozzle 51 has a plurality of flame holding members 61, 62, 63, 64 as flame holders 54 disposed therein, the fuel gas flow path is divided into nine. Become. In the flame holder 54, the widened portions 61b and 62b whose widths are widened at the front end portions are located, and the widened portions 61b and 62b have the front end surfaces aligned on the same plane as the opening 51a.

  Further, in the combustion burner 21 of the first embodiment, a guide member 55 that guides the fuel gas flowing in the fuel nozzle 51 to the axial center side is provided. The guide member 55 guides the fuel gas in a direction away from the secondary air blown by the secondary air nozzle 52.

  The guide member 55 is disposed on the inner wall surface of the tip of the fuel nozzle 51 along the circumferential direction. That is, the guide member 55 is arranged on the upper guide member 65 disposed along the upper wall surface of the fuel nozzle 51, the lower guide member 66 disposed along the lower wall surface of the fuel nozzle 51, and the left and right wall surfaces of the fuel nozzle 51. And left and right guide members 67 and 68 disposed along. And this guide member 55 is arrange | positioned at the front-end | tip part of the fuel nozzle 51 so that the wide parts 61b and 62b of the flame holder 54 may be opposed. The guide member 55 has a triangular cross section, and is formed with an inclined surface 69 whose width increases toward the downstream side in the fuel gas flow direction, and the front end thereof extends in the fuel gas flow direction. The planes are perpendicular to each other and are aligned on the same plane as the openings 51a and 52a. The guide member 55 is formed by cutting out the positions intersecting with the flame holding members 61, 62, 63, 64.

  Therefore, in the combustion burner 21, the fuel gas obtained by mixing pulverized coal and primary air is blown into the furnace from the opening 51 a of the fuel nozzle 51, and the secondary air is discharged from the secondary air nozzle 52 on the outside thereof. The air is blown into the furnace through the opening 52 a, and the tertiary air is blown into the furnace through the opening 53 a of the tertiary air nozzle 53 on the outside thereof. At this time, the fuel gas is branched and ignited by the flame holder 54 at the opening 51a of the fuel nozzle 51, and burns to become a combustion gas. Moreover, combustion of fuel gas is accelerated | stimulated because secondary air is blown in the outer periphery of this fuel gas. In addition, since the tertiary air is blown into the outer periphery of the combustion flame, the ratio of the secondary air and the tertiary 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 the configuration in which external flame holding of the combustion flame is performed, the outer peripheral portion of the combustion flame becomes low temperature, and the temperature of the outer peripheral portion of the combustion flame in a high oxygen atmosphere can be lowered by the secondary air. The amount of NOx generated at the outer periphery is reduced.

  Moreover, 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 (secondary air and tertiary air) are supplied as a straight flow. That is, it is preferable that the fuel nozzle 51, the secondary air nozzle 52, and the tertiary air nozzle 53 have a structure that supplies the fuel gas, the secondary air, and the tertiary air as a straight flow without swirling. Since the fuel gas, the secondary air, and the tertiary air are injected as a straight flow to form a combustion flame, the gas circulation in the combustion flame is suppressed in the configuration in which the combustion flame is held inside. Thereby, the outer peripheral part of a combustion flame is maintained with low temperature, and the NOx generation amount by mixing with secondary air is reduced.

  Further, in the combustion burner 21, the guide member 55 is disposed at the entire circumference at the front end portion of the fuel nozzle 51, so that the fuel gas flowing in the fuel nozzle 51 is caused by the inclined surface 69 of the guide member 55. It is guided to the axial center side, that is, the flame holder 54 side. Then, the fuel gas blown into the furnace by the fuel nozzle 51 is guided in a direction away from the secondary air blown by the secondary air nozzle 52. Therefore, the internal flame holding by the flame holder 54 is appropriately performed by separating the fuel gas from the secondary air that is relatively faster than the fuel gas. Further, the fuel gas is separated from the secondary air, so that the amount of NOx generated by mixing with the secondary air is reduced. Furthermore, pulverized coal can be appropriately supplied toward the flame holder 54.

  As described above, in the combustion burner of the first embodiment, the fuel nozzle 51 capable of injecting the fuel gas in which the pulverized coal and the primary air are mixed, and the secondary air 2 can be injected from the outside of the fuel nozzle 51. A secondary air nozzle 52 is provided, a flame stabilizer 54 is provided on the axial center side of the tip of the fuel nozzle 51, and a guide member 55 for guiding the fuel gas flowing in the fuel nozzle 51 to the axial center side is provided.

  Therefore, the fuel gas flowing in the fuel nozzle 51 is guided to the axial center side of the fuel nozzle 51, that is, the flame stabilizer 54 side by the guide member 55, and the proper flow of the fuel gas in the fuel nozzle 51 is made. As a result, the internal flame holding performance by the flame holder 54 can be improved.

  In the combustion burner of the first embodiment, the guide member 55 guides the fuel gas in a direction away from the secondary air blown by the secondary air nozzle 52. Therefore, the fuel gas is guided in a direction away from the secondary air by the guide member 55, mixing of the fuel gas and the secondary air is suppressed, and the internal flame holding performance by the flame holder 54 can be improved. In addition, since the outer peripheral portion of the combustion flame is maintained at a low temperature, the amount of NOx generated by mixing the combustion gas and the secondary air can be reduced.

  In the combustion burner according to the first embodiment, the guide member 55 is disposed along the inner wall surface of the fuel nozzle 51. Therefore, the fuel gas flowing in the fuel nozzle 51 over the entire area of the fuel nozzle 51 can be guided to the flame stabilizer 54 side, and the fuel gas can be guided in a direction away from the secondary air. The internal flame holding performance by the flame holder 54 can be improved.

  In the combustion burner according to the first embodiment, the guide member 55 is disposed at the tip of the fuel nozzle 51 so as to face the flame holder 54. In this case, the guide member 55 is disposed to face the widened portions 61b and 62b in the flame holder 54. Therefore, by guiding the fuel gas to the widened portions 61b and 62b in the flame holder 54 by the guide member 55, a sufficient flame holding function can be secured and the internal flame holding performance can be improved.

  FIG. 5 is a cross-sectional view illustrating a combustion burner according to a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the function similar to the Example mentioned above, and detailed description is abbreviate | omitted.

  In the combustion burner according to the second embodiment, as shown in FIG. 5, the combustion burner 21 is provided with a fuel nozzle 51, a secondary air nozzle 52, and a tertiary air nozzle 53 from the center side. 54 is provided. A guide member 71 that guides the fuel gas in a direction away from the secondary air blown by the secondary air nozzle 52 by guiding the fuel gas flowing in the fuel nozzle 51 to the axial center side is provided.

  The guide member 71 is located at a position not facing the flame holder 54 disposed in the fuel nozzle 51, that is, upstream of the flame holder 54 in the fuel gas flow direction and on the inner wall surface of the fuel nozzle 51. Arranged along the circumferential direction. The guide member 71 has a ring shape that protrudes from the inner wall surface of the fuel nozzle 51 toward the flame holder 54, and a guide surface (inclined surface or curved surface) 72 that guides the fuel gas in the fuel nozzle 51 to the axial center side. Is formed.

  Accordingly, in the combustion burner 21, the guide member 71 is arranged at the entire circumference at the front end portion of the fuel nozzle 51, so that the fuel gas flowing in the fuel nozzle 51 is caused by the guide surface 72 of the guide member 71. It is guided to the axial center side, that is, the flame holder 54 side. Then, the fuel gas blown into the furnace by the fuel nozzle 51 is guided in a direction away from the secondary air blown by the secondary air nozzle 52. Therefore, the internal flame holding by the flame holder 54 is appropriately performed by separating the fuel gas from the secondary air that is relatively faster than the fuel gas. Further, the fuel gas is separated from the secondary air, so that the amount of NOx generated by mixing with the secondary air is reduced.

  As described above, in the combustion burner of the second embodiment, the fuel nozzle 51 capable of injecting the fuel gas mixed with the pulverized coal and the primary air, and the secondary air capable of injecting the secondary air from the outside of the fuel nozzle 51. And a flame holder 54 on the axial center side at the tip of the fuel nozzle 51, and a guide member 71 for guiding the fuel gas flowing in the fuel nozzle 51 to the axial center side from the flame stabilizer 54. It is provided upstream in the flow direction of the fuel gas.

  Therefore, the fuel gas flowing in the fuel nozzle 51 is guided to the axial center side of the fuel nozzle 51, that is, the flame stabilizer 54 side by the guide member 71, and the proper flow of the fuel gas in the fuel nozzle 51 is caused. As a result, the internal flame holding performance by the flame holder 54 can be improved. Further, since the guide member 71 is provided on the upstream side of the flame holder 54, the fuel gas can be effectively guided to the flame holder 54, and the internal flame holding performance of the flame holder 54 is improved. be able to. Further, since the guide member 71 is not provided on the tip end side in the fuel nozzle 51, the guide member 71 itself does not function as a flame holder.

  FIG. 6 is a front view showing a combustion burner according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the function similar to the Example mentioned above, and detailed description is abbreviate | omitted.

  In the combustion burner of the third embodiment, as shown in FIG. 6, the combustion burner 21 is provided with a fuel nozzle 51, a secondary air nozzle 52, and a tertiary air nozzle 53 from the center side, and a flame holder. 54 is provided. A guide member for guiding the fuel gas in a direction away from the secondary air blown by the secondary air nozzle 52 by guiding the fuel gas flowing in the fuel nozzle 51 toward the axial center side is provided.

  The guide member is disposed at a position facing the inner wall surface of the fuel nozzle 51 at the widened portions 61 b and 62 b of the flame holder 54. That is, the flame holder 54 is arranged such that the first flame holding members 61 and 62 along the horizontal direction intersect with the second flame holding members 63 and 64 along the vertical direction. The flame holding members 61, 62, 63, 64 are configured as notched surfaces 61c, 62c, 63c, 64c formed at the ends of the widened portions 61b, 62b. Each notch surface 61c, 62c, 63c, 64c is formed to have a tapered shape by forming inclined surfaces on both sides of the end portion when the flame holding members 61, 62, 63, 64 are viewed from the front. Has been.

  Therefore, in the combustion burner 21, the notch surfaces 61c, 62c, 63c, and 64c as guide members are formed at the end portions of the flame holding members 61, 62, 63, and 64 of the flame holder 54, so that the fuel nozzle The fuel gas flowing in 51 is guided to the axial center side, that is, the inner side in the longitudinal direction of each flame-holding member 61, 62, 63, 64 by the notch surfaces 61c, 62c, 63c, 64c. That is, when the fuel gas passes through the vicinity of the notch surfaces 61c, 62c, 63c, 64c of the flame holding members 61, 62, 63, 64, the front side of each flame holding member 61, 62, 63, 64 becomes negative pressure. As the fuel gas is drawn into the negative pressure region, a flow indicated by an arrow in FIG. 6 is generated.

  Then, the fuel gas blown into the furnace by the fuel nozzle 51 is guided in a direction away from the secondary air blown by the secondary air nozzle 52. Therefore, the internal flame holding by the flame holder 54 is appropriately performed by separating the fuel gas from the secondary air that is relatively faster than the fuel gas. Further, the fuel gas is separated from the secondary air, so that the amount of NOx generated by mixing with the secondary air is reduced.

  As described above, in the combustion burner of the third embodiment, the fuel nozzle 51 capable of blowing the fuel gas mixed with the pulverized coal and the primary air, and the secondary air 2 can be blown from the outside of the fuel nozzle 51. And a flame holder 54 on the axial center side at the tip of the fuel nozzle 51, and a guide member for guiding the fuel gas flowing in the fuel nozzle 51 to the axial center side. Cutout surfaces 61c, 62c, 63c, and 64c are formed at the ends of the flame holding members 61, 62, 63, and 64, respectively.

  Therefore, the fuel gas flowing in the fuel nozzle 51 is guided to the axial center side of the fuel nozzle 51 by the notch surfaces 61c, 62c, 63c, and 64c, that is, the center side of the flame holder 54, Thus, an appropriate flow of the fuel gas can be realized, and as a result, the internal flame holding performance by the flame holder 54 can be improved. In addition, since the guide member is configured by forming the cut-out surfaces 61c, 62c, 63c, and 64c at the end of the flame holder 54, the apparatus can be simplified.

  In Example 3, the guide member was a notched surface 61c, 62c, 63c, 64c having a tapered shape formed at the end in the longitudinal direction of the flame holding members 61, 62, 63, 64. It is not limited to this shape. For example, the longitudinal ends of the flame holding members 61, 62, 63, 64 are cut out only on one side to form a cut surface, or in the direction perpendicular to the longitudinal direction of the flame holding members 61, 62, 63, 64. By cutting, a notch portion that is separated from the inner wall surface of the fuel nozzle 51 may be used. Moreover, each notch surface 61c, 62c, 63c, 64c is good also as a shape where the downstream of the flow direction of fuel gas is widened similarly to the wide part 61b, 62b.

  FIG. 7 is a front view showing a combustion burner according to Embodiment 4 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the function similar to the Example mentioned above, and detailed description is abbreviate | omitted.

  In the combustion burner of the fourth embodiment, as shown in FIG. 7, the combustion burner 21 is provided with a fuel nozzle 51, a secondary air nozzle 52, and a tertiary air nozzle 53 from the center side, and a flame holder. 54 is provided. A guide member for guiding the fuel gas in a direction away from the secondary air blown by the secondary air nozzle 52 by guiding the fuel gas flowing in the fuel nozzle 51 toward the axial center side is provided.

  This guide member is disposed as a triangular plate 81, 82, 83, 84 outside the position where the first flame holding member 61, 62 and the second flame holding member 63, 64 intersect. Specifically, the outside of the position where the widened portions 61b, 62b of the first flame holding members 61, 62 intersect with the widened portions (not shown) of the second flame holding members 63, 64, that is, the axis of the fuel nozzle 51. It is arranged on the opposite side to the center. Each of the triangular plates 81, 82, 83, 84 is formed in a triangular shape by forming inclined surfaces outside the intersecting corners when the flame holding members 61, 62, 63, 64 are viewed from the front. Has been.

  Therefore, in the combustion burner 21, the triangular plates 81, 82, 83, and 84 are disposed outside the flame holders 54, 62, 63, and 64 of the flame holder 54, and thus flow through the fuel nozzle 51. The fuel gas is guided to the axial center side by the triangular plates 81, 82, 83, 84, that is, to the center portions of the flame holding members 61, 62, 63, 64. That is, when the fuel gas passes in the vicinity of each triangular plate 81, 82, 83, 84, the front side of each triangular plate 81, 82, 83, 84 becomes negative pressure, and the fuel gas is drawn into this negative pressure region, A flow indicated by an arrow in FIG. 7 occurs.

  Then, the fuel gas blown into the furnace by the fuel nozzle 51 is guided in a direction away from the secondary air blown by the secondary air nozzle 52. Therefore, the internal flame holding by the flame holder 54 is appropriately performed by separating the fuel gas from the secondary air that is relatively faster than the fuel gas. Further, the fuel gas is separated from the secondary air, so that the amount of NOx generated by mixing with the secondary air is reduced.

  As described above, in the combustion burner according to the fourth embodiment, the fuel nozzle 51 capable of injecting the fuel gas mixed with the pulverized coal and the primary air, and the secondary air capable of injecting the secondary air from the outside of the fuel nozzle 51 are provided. And a flame holder 54 on the axial center side at the tip of the fuel nozzle 51, and a guide member for guiding the fuel gas flowing in the fuel nozzle 51 to the axial center side. Triangular plates 81, 82, 83, 84 are arranged outside the positions where the flame holding members 61, 62, 63, 64 intersect.

  Therefore, the fuel gas flowing in the fuel nozzle 51 is guided to the axial center side of the fuel nozzle 51 by the triangular plates 81, 82, 83, 84, that is, the center side of the flame holder 54. An appropriate flow of the fuel gas can be realized, and as a result, the internal flame holding performance by the flame holder 54 can be improved. Further, the flame holder 54 includes two first flame holding members 61 and 62 that are parallel with a predetermined gap in the vertical direction along the horizontal direction, and two that are parallel with a predetermined gap in the horizontal direction along the vertical direction. The second flame holding members 63 and 64 are arranged so as to intersect with each other. Therefore, it is possible to ensure a sufficient flame holding function by making the flame holder 54 have a double cross structure. Further, by using the triangular plates 81, 82, 83, 84 as the guide members, the fuel gas flowing in the fuel nozzle 51 can be effectively guided to the axial center side.

  In the fourth embodiment, the guide members are triangular plates 81, 82, 83, and 84, but are not limited to this shape. For example, each triangular plate 81, 82, 83, 84 may have a shape in which the downstream side in the fuel gas flow direction widens, like the widened portions 61b, 62b.

  FIG. 8 is a cross-sectional view illustrating a combustion burner according to a fifth embodiment of the present invention, and FIG. 9 is a cross-sectional view illustrating a modification of the combustion burner according to the fifth embodiment. In addition, the same code | symbol is attached | subjected to the member which has the function similar to the Example mentioned above, and detailed description is abbreviate | omitted.

  In the combustion burner of the fifth embodiment, as shown in FIG. 8, the combustion burner 21 is provided with a fuel nozzle 51, a secondary air nozzle 52, and a tertiary air nozzle 53 from the center side, and a flame holder. 91 is provided. A guide member for guiding the fuel gas in a direction away from the secondary air blown by the secondary air nozzle 52 by guiding the fuel gas flowing in the fuel nozzle 51 toward the axial center side is provided.

  That is, the flame holder 91 includes flame holding members 92 and 93 extending in the horizontal direction. The flame holding members 92 and 93 are flat portions 92a and 93a each having a flat plate shape with a constant thickness, and the flat portions. Wide portions 92b and 93b are provided integrally at the front ends (downstream ends in the fuel gas flow direction) of the portions 92a and 93a. The widened portions 92b and 93b have an isosceles triangular cross section, the width is widened toward the downstream side in the fuel gas flow direction, and the front end is a plane perpendicular to the fuel gas flow direction.

  The flame holding members 92 and 93 constitute a guide member with the front end portion facing the axial center side of the fuel nozzle 51. That is, the flame holding members 92 and 93 are arranged such that the widened portions 92b and 93b formed at the front end portions are closer to each other than the rear end portions of the flat portions 92a and 93a. It is inclined with respect to it.

  Accordingly, in the combustion burner 21, the flame holder 91 in the fuel nozzle 51 is arranged so that the front end portions of the flame holding members 92 and 93 are close to each other. The flame holding members 92 and 93 are guided to the axial center side. That is, since the front end portions of the flame holding members 92 and 93 are close to each other, the fuel gas becomes high speed between the flame holding members 92 and 93, while the low speed is generated between the fuel nozzle 51 and the flame holding members 92 and 93. As a whole, the fuel nozzle 51 is guided to the axial center side.

  Then, the fuel gas blown into the furnace by the fuel nozzle 51 is guided in a direction away from the secondary air blown by the secondary air nozzle 52. Therefore, the internal flame holding by the flame holder 91 is appropriately performed by separating the fuel gas from the secondary air that is relatively faster than the fuel gas. Further, the fuel gas is separated from the secondary air, so that the amount of NOx generated by mixing with the secondary air is reduced.

  In this case, the inclination angle of the flame holding members 92 and 93 constituting the flame holder 91 may be adjustable. That is, as shown in FIG. 9, the flame holding members 92 and 93 are supported by the support shafts 101 and 102 along the horizontal direction orthogonal to the fuel gas flow direction of the fuel nozzle 51 so as to be rotatable up and down. The drive device 103 can be rotated. That is, the inclination angle of the flame holding members 92 and 93 can be individually adjusted by the driving device 103.

  Therefore, for example, the drive device 103 individually adjusts the angles of the flame holding members 92 and 93 based on the nature and speed of the fuel gas, the speed of the secondary air, the combustion state in the furnace 11, and the like. It is possible to maintain the optimum state of blowing fuel gas.

  As described above, in the combustion burner of the fifth embodiment, the fuel nozzle 51 capable of injecting the fuel gas in which the pulverized coal and the primary air are mixed, and the secondary air can be injected from the outside of the fuel nozzle 51. In addition to the secondary air nozzle 52, a flame holder 91 is provided on the axial center side of the tip of the fuel nozzle 51, and the flame holder 91 serves as a guide member for guiding the fuel gas flowing in the fuel nozzle 51 to the axial center side. The flame holding members 92 and 93 are arranged so that the front end faces the axial center side of the fuel nozzle 51.

  Accordingly, the fuel gas flowing in the fuel nozzle 51 is guided to the axial center side of the fuel nozzle 51 by the inclined flame holding members 92 and 93, that is, to the center portion side of the flame holder 91. An appropriate flow of the fuel gas can be realized, and as a result, the internal flame holding performance by the flame holder 91 can be improved. In addition, since the guide member is configured by the arrangement of the flame holding members 92 and 93 in the flame holder 91, the structure can be simplified.

  In the combustion burner of the fifth embodiment, the inclination angle of the flame holding members 92 and 93 can be individually adjusted by the driving device 103. Therefore, for example, the angle of the flame holding members 92 and 93 is changed on the basis of the nature and speed of the fuel gas, the speed of the secondary air, the combustion state in the furnace 11, and the like, so that the optimum blowing of the fuel gas is performed. It becomes possible to maintain the state.

  In addition, in each Example mentioned above, although the structure of the flame holders 54 and 91 was mentioned and demonstrated variously, this structure is not limited to what was mentioned above. That is, the burner of the present invention realizes internal flame holding, and it is sufficient that a flame holder is provided on the axial center side of the fuel nozzle 51 instead of the inner wall surface of the fuel nozzle 51. The number, position, etc. may be set as appropriate, and the flame holding member may be separated from the inner wall surface of the fuel nozzle 51. Further, the configuration of the guide member has been described with various examples, but this configuration is not limited to the above-described configuration. That is, it is only necessary that the fuel gas in the fuel nozzle can be guided to the axial center side by the guide member.

  Moreover, although the flame holder of this invention provided the wide part of triangular cross-sectional shape, it is not limited to this shape, A square shape may be sufficient and a wide part may be eliminated.

  In each of the above-described embodiments, the guide member of the present invention is provided on the inner wall surface of the fuel nozzle or the flame holder. However, another member is provided between the inner wall surface of the fuel nozzle and the flame holder. May be. For example, a guide member may be provided between the inner wall surface of the fuel nozzle and the flame holder along a direction parallel to or intersecting with the flame holder, so that the guide member may have a rectangular shape or a rhombus frame shape. .

  In each of the above-described embodiments, the combustion apparatus 12 is configured by arranging four combustion burners 21, 22, 23, 24, and 25 provided on the wall surface of the furnace 11 along the vertical direction. 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 Secondary air nozzle 53 Tertiary air nozzle 54, 91 Flame holder 55, 71 Guide members 61, 62, 63, 64 Flame member 61c, 62c, 63c, 64c Notch surface (guide member)
81, 82, 83, 84 Triangular plate (guide member)
103 Drive device

Claims (7)

A fuel nozzle for supplying fuel gas into the furnace;
A secondary air nozzle for supplying secondary air from the outside of the fuel nozzle;
A flame holder provided downstream of the fuel nozzle in the fuel gas flow direction;
A guide member provided at a position facing the flame holder at the tip of the fuel nozzle;
Bei example,
The guide member is disposed between an inner wall surface of the fuel nozzle and the flame holder.
Combustion burner characterized by that.   2. The combustion burner according to claim 1, wherein the guide member guides the fuel gas to an axial center side of the fuel nozzle at a tip portion of the fuel nozzle.   The combustion burner according to claim 1 or 2, wherein the guide member guides the fuel gas in a direction away from the front secondary air.   The combustion burner according to any one of claims 1 to 3, wherein the guide member is disposed along an inner wall surface of the fuel nozzle. The flame stabilizer has a widened portion on the downstream side in the flow direction of the fuel gas, the guide member includes any one of claims 1-4, characterized in that arranged opposite to the wider section The combustion burner according to one. The said guide member has the inclined surface which guides the said fuel gas toward the said flame holder side at the downstream of the flow direction of the said fuel gas, The any one of Claim 1 to 5 characterized by the above-mentioned. The combustion burner described in. The combustion burner according to any one of claims 1 to 6 , wherein a plurality of the flame stabilizers are provided, and a plurality of the flow paths of the fuel gas are divided at the opening of the fuel nozzle.

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