JP5960022B2 - boiler - Google Patents

Description

  The present invention relates to a boiler that generates steam by burning solid fuel and air.

  Conventional coal-fired boilers have a hollow furnace that is installed in the vertical direction, and a plurality of combustion burners are arranged along the circumferential direction on the furnace wall, and arranged in multiple stages in the vertical direction. Has been. The combustion burner is supplied with a mixture of pulverized coal (fuel) obtained by pulverizing coal and primary air (carrier air), and also supplied with high-temperature secondary air. The mixture and secondary air are supplied to the combustion burner. Is blown into the furnace to form a flame that can be burned 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.

  In such a coal fired boiler, the combustion burner is supplied with a mixed fuel of pulverized coal and carrier air from a pulverized coal container through a pulverized coal supply pipe, and blows this mixed fuel and secondary air into the furnace. A flame is formed. The pulverized coal passes through the bent pulverized coal supply pipe until it is sent from the pulverized coal burner to the combustion burner, and the pulverized coal flowing in the pulverized coal supply pipe has a concentration deviation in the passage cross section. In particular, if the pulverized coal supply pipe is bent immediately before reaching the combustion burner, the pulverized coal collects in the bent direction or in the opposite direction, causing a bias in the mixed fuel injection by the combustion burner and unstable combustion. End up.

  As what solves such a problem, there exists a thing described in the following patent document 1, for example. The pulverized coal combustor described in Patent Document 1 cancels the pulverized coal drift by disposing a spiral rifle plate or fin on the inner surface of the final straight pipe portion of the pulverized coal pipe that guides the pulverized coal to the burner. By providing the core, the concentration distribution of the pulverized coal in the central part of the jet injected from the burner is lowered, and the concentration distribution of the pulverized coal in the periphery is increased.

Japanese Patent Laid-Open No. 10-292903

  In the conventional pulverized coal combustor, the concentration distribution of the pulverized coal in the central portion of the jet injected from the burner by the core is lowered and the concentration distribution of the pulverized coal in the periphery is increased. However, the combustion burner using Patent Document 1 described above forms a flame by injecting a mixed fuel of pulverized coal fuel and primary air and injecting high-temperature secondary air to the outside thereof. If the pulverized fuel is concentrated outside the pulverized coal pipe in this way, the pulverized coal pipe may be worn due to the collision.

  The present invention solves the above-described problems, and an object of the present invention is to provide a boiler that can suppress the occurrence of unstable combustion due to uneven fuel injection and wear in the fuel gas supply passage.

  In order to achieve the above object, a boiler according to the present invention includes a furnace having a hollow shape and installed in a vertical direction, a fuel gas supply passage capable of supplying a fuel gas mixed with solid fuel and air, A combustion burner capable of forming a flame by blowing the fuel gas supplied through the fuel gas supply passage into the furnace, and a guide for guiding the solid fuel flowing through the fuel gas supply passage toward the center of the combustion burner And a member.

  Therefore, the fuel gas mixed with the solid fuel and air is supplied to the combustion burner through the fuel gas supply passage, and the combustion burner can form a flame by blowing this fuel gas into the furnace, At this time, since the guide member guides the solid fuel flowing through the fuel gas supply passage to the center portion side of the combustion burner, the fuel gas jet injected by the combustion burner has a solid fuel concentration higher on the center portion side, It is possible to form a stable flame at the center of the fuel and to suppress the occurrence of wear in the fuel gas supply passage.

  In the boiler according to the present invention, the guide member has an inclined surface that guides the solid fuel toward the center of the combustion burner.

  Therefore, when the fuel gas mixed with the solid fuel and air is supplied to the combustion burner through the fuel gas supply passage, the solid fuel is guided to the center side of the combustion burner by the inclined surface, and the simple configuration Thus, it is possible to easily form a jet having a high solid fuel concentration on the center side.

  In the boiler according to the present invention, the guide member has a guide body having a cylindrical shape that tapers toward the combustion burner, has the inclined surface inside the guide body, and is provided with a central passage opening. In addition, an outer passage opening is provided between the inner peripheral surface of the fuel gas supply passage.

  Therefore, by providing the central passage opening on the inside of the guide body and the outer passage opening on the outside, the solid fuel in the fuel gas is not deposited on the center side or the outer peripheral side of the guide member, and the fuel gas A stable flow of fuel gas in the supply passage can be ensured.

  In the boiler according to the present invention, the outer passage opening has a ring shape, and a plurality of connecting portions that connect the guide body and the inner peripheral surface of the fuel gas supply passage are provided at predetermined intervals in the circumferential direction. It is said.

  Accordingly, when the fuel gas flows through the outer passage opening, the flow is disturbed by the plurality of connecting portions, so that mixing of the solid fuel and air is promoted, and the solid fuel in the fuel gas is Dispersed, the concentration distribution of the solid fuel outside the guide body is made uniform, and stable ignition can be achieved.

  In the boiler according to the present invention, the connecting portion has a tapered shape in a direction opposite to the flow direction of the fuel gas.

  Therefore, when the fuel gas collides with the connecting portion, the solid fuel is not deposited on the connecting portion, and an appropriate flow of the fuel gas can be ensured.

  The boiler according to the present invention is characterized in that a plurality of protrusions extending from the guide body toward the central passage opening are provided at predetermined intervals in the circumferential direction.

  Therefore, when the fuel gas flows through the central passage opening, the flow is disturbed by the plurality of protrusions, so that mixing of the solid fuel and air is promoted, and the solid fuel in the fuel gas is dispersed, The concentration distribution of the solid fuel inside the guide body is made uniform, and stable ignition can be achieved.

  The boiler according to the present invention is characterized in that the protrusion has a tapered shape in a direction opposite to the flow direction of the fuel gas.

  Therefore, when the fuel gas collides with the protrusion, the solid fuel is not deposited on the protrusion, and an appropriate flow of the fuel gas can be ensured.

  In the boiler according to the present invention, a plurality of connecting portions that connect the guide main body and the inner peripheral surface of the fuel gas supply passage are provided at predetermined intervals in the circumferential direction, and extend from the guide main body toward the central passage opening. A plurality of protruding portions are provided at predetermined intervals in the circumferential direction, and the connecting portion and the protruding portion are provided at positions shifted in the circumferential direction.

  Therefore, when the fuel gas flows through the outer passage opening, the flow is disturbed by the plurality of connecting portions, so that the solid fuel in the fuel gas is dispersed at the outer periphery, and the fuel gas passes through the center passage opening. When flowing, the flow is disturbed by the plurality of protrusions, so that the solid fuel in the fuel gas is dispersed here, and at this time, the connecting portion and the protrusion are displaced in the circumferential direction, The fuel gas dispersed in the outer passage opening and the fuel gas dispersed in the center passage opening are promoted to mix solid fuel and air, respectively, and can be stably ignited.

  According to the boiler of the present invention, since a fuel gas supply passage capable of supplying a fuel gas mixed with solid fuel and air to the combustion burner is provided, and a guide member for guiding the solid fuel to the center side of the combustion burner is provided, The fuel gas jet injected by the combustion burner has a high concentration of solid fuel on the center side, can form a stable flame at the center of the jet, and suppress the occurrence of wear in the fuel gas supply passage Can do.

FIG. 1 is a schematic configuration diagram illustrating a coal fired boiler according to a first embodiment of the present invention. FIG. 2 is a plan view of a combustion burner in the coal fired boiler according to the first embodiment. FIG. 3 is a schematic diagram showing a combustion burner and a pulverized coal supply pipe. FIG. 4 is a perspective view of the guide member. FIG. 5 is a cross-sectional view of a guide member provided in the pulverized coal supply pipe. FIG. 6 is a front view of a guide member provided in the pulverized coal supply pipe. FIG. 7 is a side view of the guide member provided in the pulverized coal supply pipe in the coal burning boiler according to the second embodiment of the present invention. FIG. 8 is a sectional view of a guide member provided in the pulverized coal supply pipe.

  Exemplary embodiments of a boiler 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.

  1 is a schematic configuration diagram illustrating a coal burning boiler according to a first embodiment of the present invention, FIG. 2 is a plan view of a combustion burner in the coal burning boiler according to the first embodiment, and FIG. 3 is a combustion burner and a pulverized coal supply pipe. 4 is a perspective view of the guide member, FIG. 5 is a sectional view of the guide member provided in the pulverized coal supply pipe, and FIG. 6 is a front view of the guide member provided in the pulverized coal supply pipe. It is.

  The boiler of Example 1 uses pulverized coal obtained by pulverizing coal (bituminous coal, subbituminous coal, etc.) as a pulverized fuel, burns the pulverized coal with a combustion burner, and recovers the heat generated by the combustion. It is a charcoal fired boiler.

  In the first embodiment, as shown in FIG. 1, the coal fired 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. The furnace wall constituting the furnace 11 is constituted by a heat transfer tube.

  The combustion device 12 is provided in a lower part of a furnace wall (heat transfer tube) constituting the furnace 11. This combustion apparatus 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. The shape of the furnace, the number of combustion burners in one stage, and the number of stages are not limited to this embodiment.

  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. 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. Therefore, the combustion air (secondary air) sent by the blower 38 is supplied from the air duct 37 to the wind box 36 and supplied from the wind box 36 to the combustion burners 21, 22, 23, 24, 25. In addition, combustion air (tertiary 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 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. Further, the additional air nozzle 39 can blow tertiary air into the furnace 11. 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.

  Further, the form of the combustion burner is not limited to that described above. That is, the attachment position of the combustion burner may be not the corner of the furnace 11 but the wall of the furnace 11. Further, the combustion burner may be a system that forms a flame counterflow instead of a flame swirl flow, or may be provided only on the wall of the furnace 11.

  The furnace 11 has a flue 50 connected to the upper portion thereof, and superheaters (superheaters) 51 and 52 and reheaters 53 and 54 for recovering heat of exhaust gas as a convection heat transfer section. The economizers 55, 56, and 57 are provided, and heat exchange is performed between the exhaust gas generated by the combustion in the furnace 11 and the water.

  The flue 50 is connected to an exhaust gas pipe 58 from which exhaust gas subjected to heat exchange is discharged downstream. The exhaust gas pipe 58 is provided with an air heater 59 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 58, 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 58 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 50 is discharged.

  At this time, 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 the tertiary air (additional air) is additionally supplied to complete the oxidation combustion of the pulverized coal, and the generation of NOx due to the combustion of the pulverized coal. The amount is reduced. That is, in the furnace 11, the NOx reduction region A is formed between the combustion burner 21 and the additional air nozzle 39.

  The water supplied from a water supply pump (not shown) is preheated by the economizers 55, 56, and 57, then supplied to a steam drum (not shown) and supplied to each water pipe (not shown) on the furnace wall. It 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 51 and 52 and is superheated by the combustion gas. The superheated steam generated by the superheaters 51 and 52 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 53 and 54, 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 55, 56, and 57 of the flue 50 is subjected to removal of harmful substances such as NOx by a catalyst in a denitration device (not shown) in the exhaust gas pipe 58, 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 at four corners 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 at each corner 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. Inject combustion air into 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).

  By the way, as shown in FIG. 1, in such a coal fired boiler 10, the combustion burners 21, 22, 23, 24, and 25 are connected to the pulverized coal supply pipe 26 from the pulverized coal units 31, 32, 33, 34, and 35. , 27, 28, 29, and 30, a mixed fuel of pulverized coal and carrier air is sent, and a flame is formed by blowing this mixed fuel and primary air outside thereof into the furnace 11. In this case, since the pulverized coal supply pipes 26, 27, 28, 29, and 30 are bent and arranged, the pulverized coal flowing inside the pulverized coal supply pipes 26, 27, 28, 29, and 30 Concentration deviation occurs in the passage cross section. In particular, if the pulverized coal supply pipes 26, 27, 28, 29, 30 are bent immediately before reaching the combustion burners 21, 22, 23, 24, 25, the pulverized coal collects in the bent direction or the opposite direction. In addition, the mixed fuel injection by the combustion burners 21, 22, 23, 24, and 25 is biased, and the combustion becomes unstable.

  Therefore, in Example 1, the pulverized coal (solid fuel) flowing through the pulverized coal supply pipes (fuel gas supply passages) 26, 27, 28, 29, 30 is converted into the center side of the combustion burners 21, 22, 23, 24, 25. The guide member which guides to is provided.

  Hereinafter, the guide member will be described in detail. The guide member is provided in each pulverized coal supply pipe 26, 27, 28, 29, 30 and has the same configuration. Therefore, the mixed fuel is supplied to the combustion burner 21. Only the guide member provided in the supplied pulverized coal supply pipe 26 will be described.

  In Example 1, as shown in FIG. 3, the combustion burner 21 is provided in the furnace wall 11a of the furnace 11, the front-end | tip part faces in the furnace 11, and the pulverized coal supply pipe 26 is connected to the base end part. Has been. The pulverized coal supply pipe 26 has a pulverized coal machine 31 (see FIG. 1) connected to a base end portion and a combustion burner 21 connected to a distal end portion. The pulverized coal supply pipe 26 includes a first straight portion 61, a bent portion 62, and a second straight portion 63 that are continuously provided, and the combustion burner 21 is connected to the second straight portion 63.

  The combustion burner 21 includes a first nozzle 71 capable of blowing a mixed fuel obtained by mixing pulverized coal and transport air, and a second nozzle 72 capable of blowing combustion air from the outside of the first nozzle 71. It is configured. The first nozzle 71 has a base end connected to the pulverized coal supply pipe 26, and the second nozzle 72 has a base end connected to the wind box 36.

  The pulverized coal supply pipe 26 has a kicker 64 fixed to the bent portion 62 side of the second straight portion 63. The kicker 64 is fixed to the inner surface of the second linear portion 63 on the downstream side of the outer peripheral portion of the bent portion 62. The mixed fuel flowing through the pulverized coal supply pipe 26 is supplied from the pulverized coal machine 31 to the combustion burner 21 through the first straight part 61, the bent part 62, and the second straight part 63 in the pulverized coal supply pipe 26. At this time, the pulverized coal contained in the mixed fuel is guided to the outer peripheral side of the bent portion 62 by the centrifugal force when passing through the bent portion 62. Therefore, when the pulverized coal flowing on the outer peripheral side of the bent portion 62 reaches the second straight portion 63, the inner surface of the second straight portion 63 on the downstream side of the bent portion 62 is worn out. Therefore, by providing the kicker 64 here, the wear of the inner surface of the second straight part 63 is suppressed, and the pulverized coal flowing on the inner surface of the second straight part 63 on the kicker 64 side is moved to the center side of the second straight part 63. To guide you to.

  Further, the pulverized coal supply pipe 26 is provided with a guide member 81 at the second linear portion 63, and the guide member 81 is disposed on the downstream side of the kicker 64. The guide member 81 guides the pulverized coal flowing through the pulverized coal supply pipe 26 toward the center of the combustion burner 21.

  As shown in FIGS. 3 to 6, the guide member 81 has a guide body 82 having a cylindrical shape that tapers toward the combustion burner 21, and the guide body 82 has a small diameter portion 82 a on the distal end side. A large-diameter portion 82b on the proximal end side is provided. The guide body 82 is provided with a central passage opening 83 on the inner side, and the inner peripheral surface is an inclined surface 84 that guides the pulverized coal to the center side of the combustion burner 21. Further, the guide main body 82 is configured such that the outer diameter of the large diameter portion 82 b is set smaller than the inner diameter of the pulverized coal supply pipe 26, so that the outer passage opening 85 is provided between the outer peripheral portion and the inner surface of the pulverized coal supply pipe 26. Is provided.

  The guide main body 82 is provided with a plurality of protrusions 86 extending from the small diameter portion 82 a toward the center of the central passage opening 83. The plurality of protrusions 86 are fixed to the central passage opening 83 side of the small diameter portion 82a, and are arranged at predetermined intervals (preferably at equal intervals) in the circumferential direction. Each protrusion 86 is disposed along a direction substantially orthogonal to the flow direction of the mixed fuel flowing in the pulverized coal supply pipe 26. In addition, not only this arrangement | positioning but each protrusion part 86 may be arrange | positioned inclining to the downstream in the flow direction of the mixed fuel which the front-end | tip part flows through the inside of the pulverized coal supply pipe 26.

  The outer passage opening 85 has a ring shape, and the outer passage opening 85 is provided with a plurality of connecting portions 87 for connecting the large diameter portion 82b of the guide body 82 and the inner surface of the pulverized coal supply pipe 26. ing. One end of the plurality of connecting portions 87 is fixed to the outer passage opening 85 side of the large diameter portion 82b, the other end is fixed to the inner surface of the pulverized coal supply pipe 26, and a predetermined interval (preferably, Are arranged at equal intervals). Each connecting portion 87 is disposed along a direction substantially orthogonal to the flow direction of the mixed fuel flowing in the pulverized coal supply pipe 26. In addition, not only this arrangement | positioning but each connection part 87 may be inclined and arrange | positioned in the flow direction of the mixed fuel which flows through the inside of the pulverized coal supply pipe 26.

  In this case, the plurality of protrusions 86 located in the central passage opening 85 and the plurality of connecting portions 87 located in the outer passage opening 85 are provided at positions shifted in the circumferential direction. Specifically, the same number of the plurality of protruding portions 86 and the plurality of connecting portions 87 are provided and are alternately arranged in the circumferential direction.

  Therefore, the mixed fuel obtained by mixing the pulverized coal and the conveying air is supplied to the first nozzle 71 of the combustion burner 21 through the pulverized coal supply pipe 26. The combustion air is supplied from the wind box 36 to the second nozzle 72 of the combustion burner 21.

  The mixed fuel flowing through the pulverized coal supply pipe 26 is supplied to the combustion burner 21 through the first straight portion 61, the bent portion 62, and the second straight portion 63. At this time, the mixed fuel that passes through the second straight portion 63 from the bent portion 62 is guided to the outer peripheral side of the bent portion 62 by the centrifugal force, but is guided to the central portion side of the second straight portion 63 by the kicker 64. .

  Further, after the mixed fuel flowing through the pulverized coal supply pipe 26 passes through the kicker 64, the pulverized coal is guided to the center portion side of the combustion burner 21 by the guide member 81. That is, the pulverized coal is guided to the center side of the pulverized coal supply pipe 26 by the inclined surface 84 of the guide member 81 so that the mixed fuel flowing through the pulverized coal supply pipe 26 is pulverized coal on the center side. The concentration becomes high.

  Further, when the mixed fuel passes through the central passage opening 83, the flow of fuel is disturbed by colliding with the plurality of protrusions 86. Therefore, the mixed fuel that has passed through the central passage opening 83 is promoted to be mixed with solid fuel and air in this region, and the pulverized coal concentration distribution is made uniform. On the other hand, when the mixed fuel passes through the outer passage opening 85, the mixed fuel collides with the plurality of connecting portions 87, thereby disturbing the flow. Therefore, in the mixed fuel that has passed through the outer passage opening 85, mixing of pulverized coal and air is promoted in this region, and the pulverized coal concentration distribution is made uniform. In this case, since each projection 86 in the central passage opening 83 and each coupling portion 87 in the outer passage opening 85 are displaced in the circumferential direction, mixing of solid fuel and air is further promoted.

  Thereafter, in the combustion burner 21, the first nozzle 71 blows into the furnace 11 the mixed fuel in which the pulverized coal supplied from the pulverized coal supply pipe 26 and the carrier air are mixed, while the second nozzle 72 Combustion air supplied from 36 is blown into the furnace 11. Each nozzle 71, 72 becomes a flame near the outlet of the furnace 11. At this time, since the mixed fuel blown into the furnace 11 is blown in such a manner that air is surrounded on the outside thereof, an appropriate flame without fear of misfire is formed.

  As described above, in the boiler according to the first embodiment, the furnace 11 installed in the vertical direction with a hollow shape, and the pulverized coal supply pipe 26 capable of supplying the mixed fuel obtained by mixing the pulverized coal and the conveying air. A combustion burner 21 capable of forming a flame by blowing the mixed fuel supplied from the pulverized coal supply pipe 26 into the furnace 11, and the pulverized coal flowing through the pulverized coal supply pipe 26 to the center side of the combustion burner 21. A guide member 81 is provided for guiding the guide.

  Therefore, the mixed fuel is supplied to the combustion burner 21 through the pulverized coal supply pipe 26, and the combustion burner 21 can form a flame by blowing this mixed fuel into the furnace 11, and at this time, Since the guide member 81 guides the pulverized coal flowing through the pulverized coal supply pipe 26 to the center side of the combustion burner 21, the jet of the mixed fuel injected by the combustion burner 21 has a higher pulverized coal concentration on the center side, A stable flame can be formed at the center of the jet and the occurrence of wear in the pulverized coal supply pipe 26 can be suppressed.

  In the boiler according to the first embodiment, the guide member 81 is provided with an inclined surface 84 that guides pulverized coal to the center side of the combustion burner 21. Therefore, when the mixed fuel is supplied to the combustion burner 21 through the pulverized coal supply pipe 26, the pulverized coal is guided to the center side of the combustion burner 21 by the inclined surface 84, and can be easily achieved with a simple configuration. A jet having a high pulverized coal concentration at the center side can be formed.

  In the boiler according to the first embodiment, a guide main body 82 having a cylindrical shape tapered toward the combustion burner 21 and having an inclined surface 84 therein is provided, a central passage opening 83 is provided, and the inside of the pulverized coal supply pipe 26 is provided. An outer passage opening 85 is provided between the peripheral surface and the peripheral surface. Therefore, by providing the central passage opening 83 inside the guide member 81 and providing the outer passage opening 85 outside, the pulverized coal in the mixed fuel is deposited on the small diameter portion 82a and the large diameter portion 82b of the guide body 82. The stable flow of the mixed fuel in the pulverized coal supply pipe 26 can be ensured.

  In the boiler according to the first embodiment, the outer passage opening 85 has a ring shape, and a plurality of connecting portions 87 that connect the guide body 82 and the inner peripheral surface of the pulverized coal supply pipe 26 are provided at predetermined intervals in the circumferential direction. Therefore, when the mixed fuel flows through the outer passage opening 85, the flow is disturbed by the plurality of connecting portions 87, so that mixing of the pulverized coal and air is promoted and the pulverized coal in the mixed fuel is Accordingly, the distribution of the concentration of fine powder on the outside of the guide body 82 is made uniform, so that stable ignition can be achieved. Moreover, generation | occurrence | production of a harmful | toxic substance (NOx) can be suppressed.

  In the boiler according to the first embodiment, a plurality of protrusions 86 extending from the guide body 82 toward the central passage opening 83 are provided at predetermined intervals in the circumferential direction. Accordingly, when the mixed fuel flows through the central passage opening 83, the flow is disturbed by the plurality of protrusions 86, so that mixing of the pulverized coal and air is promoted and the pulverized coal of the mixed fuel is dispersed. The pulverized coal concentration distribution inside the guide body 82 is made uniform, and stable ignition can be achieved.

  In the boiler according to the first embodiment, the plurality of connecting portions 87 and the plurality of projecting portions 86 are provided at positions shifted in the circumferential direction. Therefore, the mixed fuel dispersed at the outer passage opening 85 and the mixed fuel dispersed at the center passage opening 83 are promoted to mix with pulverized coal and air, respectively, and can be stably ignited.

  7 is a side view of a guide member provided in a pulverized coal supply pipe in a coal burning boiler according to Embodiment 2 of the present invention, and FIG. 8 is a cross-sectional view of the guide member provided in the pulverized coal supply pipe. 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 Example 2, as shown in FIGS. 7 and 8, the pulverized coal supply pipe 26 is provided with a guide member 91 on the upstream side of the combustion burner, and the guide member 91 includes the pulverized coal supply pipe 26. The flowing pulverized coal is guided to the center side of the combustion burner.

  The guide member 91 has a guide body 92 having a cylindrical shape that is tapered toward the combustion burner (toward the left side in FIG. 7). The guide body 92 is proximal to the small-diameter portion 92a on the distal end side. A large-diameter portion 92b on the side is provided. The guide main body 92 is provided with a central passage opening 93 on the inner side, and the inner peripheral surface is an inclined surface 94. Further, the guide main body 92 is configured such that the outer diameter of the large diameter portion 92 b is set smaller than the inner diameter of the pulverized coal supply pipe 26, so that the outer passage opening 95 is provided between the outer peripheral portion and the inner surface of the pulverized coal supply pipe 26. Is provided.

  The guide main body 92 is provided with a plurality of protrusions 96 extending from the small diameter portion 92 a toward the center of the central passage opening 95. The plurality of protrusions 96 are fixed to the center passage opening 93 side of the small diameter portion 92a, and are arranged at predetermined intervals (preferably at equal intervals) in the circumferential direction. Each protrusion 86 is disposed along a direction substantially orthogonal to the flow direction of the mixed fuel flowing in the pulverized coal supply pipe 26.

  The outer passage opening 95 has a ring shape, and the outer passage opening 95 is provided with a plurality of connecting portions 97 that connect the large diameter portion 92b of the guide main body 92 and the inner surface of the pulverized coal supply pipe 26. ing. One end of the plurality of connecting portions 97 is fixed to the outer passage opening 95 side of the large diameter portion 92b, the other end is fixed to the inner surface of the pulverized coal supply pipe 26, and a predetermined interval in the circumferential direction (preferably, Are arranged at equal intervals). Each connecting portion 97 is disposed along a direction substantially orthogonal to the flow direction of the mixed fuel flowing in the pulverized coal supply pipe 26.

  Each projection 96 has a tapered shape directed in the direction opposite to the flow direction of the mixed fuel. Each connecting portion 97 has a tapered shape directed in the direction opposite to the flow direction of the mixed fuel. That is, each protrusion 96 and each connecting portion 97 has a quadrangular prism shape that tapers toward the upstream side in the flow direction of the mixed fuel or a shape in which the upstream portion of the flow is tapered.

  Accordingly, the mixed fuel flowing through the pulverized coal supply pipe 26 is guided by the guide member 91 toward the center of the combustion burner. That is, the pulverized coal is guided to the center side of the pulverized coal supply pipe 26 by the inclined surface 94 of the guide member 91 so that the mixed fuel flowing through the pulverized coal supply pipe 26 is pulverized coal on the center side. The concentration becomes high.

  Further, when the mixed fuel passes through the central passage opening 93, the flow of the mixed fuel is disturbed by colliding with the plurality of protrusions 96. Therefore, the mixed fuel that has passed through the central passage opening 93 is promoted to be mixed with solid fuel and air in this region, and the pulverized coal concentration distribution is made uniform. On the other hand, the mixed fuel collides with the plurality of connecting portions 97 when passing through the outer passage opening portion 95, thereby disturbing the flow. Therefore, in the mixed fuel that has passed through the outer passage opening 95, mixing of pulverized coal and air is promoted in this region, and the pulverized coal concentration distribution is made uniform.

  Thus, in the boiler of Example 2, the guide member 91 which guide | induces the pulverized coal which flows through the pulverized coal supply pipe 26 to the center part side in a combustion burner is provided. Therefore, the jet of the mixed fuel injected by the combustion burner has a high pulverized coal concentration on the center side, can form a stable flame at the center of the jet, and can enable stable ignition. .

  In the boiler according to the second embodiment, each protrusion 96 and each connecting portion 97 have a quadrangular prism shape that tapers toward the upstream side in the flow direction of the mixed fuel. Therefore, when the mixed fuel collides with each protrusion 96 or each connection part 97, pulverized coal does not accumulate on this protrusion 96 or connection part 97, and an appropriate flow of the mixed fuel can be ensured. Moreover, since each projection part 96 and each connection part 97 are a taper shape toward the flow direction of mixed fuel, the abrasion by the collision of pulverized coal can be suppressed.

  In the embodiment described above, a cylindrical guide member is used for the cylindrical pulverized coal supply pipe. However, a rectangular guide member may be used for the rectangular pulverized coal supply pipe. On the other hand, the guide member may be a square tube. Moreover, although the guide member has a cylindrical shape that is continuous in the circumferential direction, it may be a curved plate or a flat plate that is divided into a plurality of portions in the circumferential direction.

  Moreover, in the Example mentioned above, although the boiler of this invention was used as the coal fired boiler, the boiler which uses biomass or petroleum coke as a fuel may be sufficient.

DESCRIPTION OF SYMBOLS 10 Coal-fired boiler 11 Furnace 12 Combustion device 21, 22, 23, 24, 25 Combustion burner 26, 27, 28, 29, 30 Pulverized coal supply pipe (fuel gas supply passage)
31, 32, 33, 34, 35 Pulverized coal machine 36 Wind box 64 Kicker 71 First nozzle 72 Second nozzle 81 Guide member 82 Guide body 83 Central passage opening 84 Inclined surface 85 Outer passage opening 86 Projection 87 Connection portion

Claims (5)

A furnace that is hollow and installed along the vertical direction;
A fuel gas supply passage capable of supplying a fuel gas mixed with solid fuel and air; and
A combustion burner capable of forming a flame by blowing the fuel gas supplied through the fuel gas supply passage into the furnace;
A guide member for guiding the solid fuel flowing through the fuel gas supply passage to the center side of the combustion burner;
I have a,
The guide member has an inclined surface that guides solid fuel toward a center portion side of the combustion burner, and has a guide body that has a cylindrical shape that tapers toward the combustion burner. An inclined surface is provided, a central passage opening is provided, and an outer passage opening is provided between the inner peripheral surface of the fuel gas supply passage,
A plurality of protrusions extending from the guide body toward the center passage opening are provided at predetermined intervals in the circumferential direction.
A boiler characterized by that. The boiler according to claim 1 , wherein the protrusion has a tapered shape in a direction opposite to a flow direction of the fuel gas. A furnace that is hollow and installed along the vertical direction;
A fuel gas supply passage capable of supplying a fuel gas mixed with solid fuel and air; and
A combustion burner capable of forming a flame by blowing the fuel gas supplied through the fuel gas supply passage into the furnace;
A guide member for guiding the solid fuel flowing through the fuel gas supply passage to the center side of the combustion burner;
I have a,
The guide member has an inclined surface that guides solid fuel toward a center portion side of the combustion burner, and has a guide body that has a cylindrical shape that tapers toward the combustion burner. An inclined surface is provided, a central passage opening is provided, and an outer passage opening is provided between the inner peripheral surface of the fuel gas supply passage,
A plurality of connecting portions that connect the guide main body and the inner peripheral surface of the fuel gas supply passage are provided at predetermined intervals in the circumferential direction, and a protrusion that extends from the guide main body toward the central passage opening is circumferential. Provided in a plurality at predetermined intervals in the direction, and the connecting portion and the protruding portion are provided at positions shifted in the circumferential direction.
A boiler characterized by that. Wherein the outer passage openings from claim 1, characterized in that no ring-shaped, wherein the guide body and connecting portion for connecting the inner peripheral surface of the fuel gas supply passage is provided with a plurality at predetermined intervals in the circumferential direction The boiler as described in any one of 3 . The boiler according to claim 4, wherein the connecting portion has a tapered shape in a direction opposite to the flow direction of the fuel gas.

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