WO2019150663A1 - Combustion burner and boiler - Google Patents

Abstract

The purpose of the invention is to improve ignition properties while maintaining internal flame stabilization. Provided is a combustion burner (21) comprising a fuel nozzle (61), an air nozzle (62) for combustion, a plate-shaped first member (71) that is disposed in the fuel nozzle (61) along the fuel gas (301) injection direction (Jd), and a plate-shaped second member (72) that is disposed in the fuel nozzle (61) along the injection direction (Jd) and that is disposed adjacent to an adjacent burner side (Bs) of the first member (71) in the horizontal direction (Hd) orthogonal to the injection direction (Jd). An inclined face (71c) of the first member (71) and an inclined face (72c) of the second member (72) face the adjacent burner side (Bs) and are inclined toward the adjacent burner side (Bs) relative to the injection direction (Jd) of the fuel gas (301). A flat face (71d) and a flat face (72d) face a furnace wall side (Fs) in the horizontal direction (Hd) and extend in the injection direction (Jd).

Description

Combustion burner and boiler

The present invention relates to a combustion burner that mixes and burns fuel and air, and a boiler that generates steam from combustion gas generated by the combustion burner.

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 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. The furnace has a flue connected to the upper part, and a heat exchanger such as a superheater, a reheater, and a economizer for recovering the heat of the exhaust gas is provided in the flue. Heat exchange is performed between the exhaust gas generated by the combustion and water, and steam can be generated.

As a combustion burner of such a coal fired boiler, for example, there is one described in Patent Document 1. The combustion burner described in Patent Document 1 includes a fuel nozzle capable of blowing a fuel gas in which pulverized coal and primary air are mixed, and a secondary air nozzle capable of blowing secondary air from the outside of the fuel nozzle. In addition, by providing a flame holder on the axial center side at the tip of the fuel nozzle, a pulverized coal concentrated flow is caused to collide with the flame holder to enable stable low NOx combustion over a wide load range.

International Publication No. 2016/158079

In the above-described conventional combustion burner, the flame holder is formed in a splitter shape and disposed at the tip of the fuel nozzle, thereby forming a recirculation region downstream of the flame holder and maintaining combustion of pulverized coal. . By installing this splitter in the interior, ignition is performed from the inside of the flame with a smaller amount of air, the high temperature and high oxygen region formed at the outer periphery of the flame is reduced, and NOx is reduced.

However, in the combustion burner of Patent Document 1, flame holders arranged adjacent to each other in a predetermined direction have guide surfaces that are inclined in different directions in the predetermined direction. Therefore, there is a possibility that the fuel gas flow guided by the adjacent flame holder interferes, and the low flow velocity region on the downstream side of the flame holder is reduced, so that the ignition performance by the flame holder cannot be fully exhibited. .

This invention solves the subject mentioned above, and it aims at providing the combustion burner and boiler which improved ignitability, maintaining internal flame holding performance.

In order to solve the above problems, a combustion burner according to an aspect of the present disclosure includes a fuel nozzle that ejects a fuel gas in which fuel and air are mixed, and a combustion air nozzle that ejects air from the outside of the fuel nozzle. A plate-like first member disposed in the fuel nozzle along the ejection direction of the fuel gas, and a predetermined direction disposed in the fuel nozzle along the ejection direction and intersecting the ejection direction. A plate-like second member disposed adjacent to one side of the first member, the first member including a first inclined surface disposed at a downstream end in the ejection direction, and the ejection direction. A second flat surface disposed at the downstream end in the ejection direction and a second inclined surface disposed at the downstream end in the ejection direction. A flat surface, the first inclined surface and the first surface The inclined surface is a surface that faces the one side and is inclined toward the one side with respect to the ejection direction, and the first flat surface and the second flat surface are surfaces on the other side in the predetermined direction. And a surface extending along the ejection direction.

According to the above configuration, the fuel gas is deflected by the first inclined surface of the first member inclined toward one side of the predetermined direction intersecting the fuel gas ejection direction, and then at the end of the first inclined surface. Since the fuel gas flow is separated, a fuel gas recirculation region is formed on the downstream side of the first member. Similarly, the fuel gas flows at the end of the second inclined surface after the fuel gas is deflected by the second inclined surface of the second member inclined toward one side in a predetermined direction intersecting the fuel gas ejection direction. As a result, the fuel gas recirculation region is formed on the downstream side of the second member. Thus, internal flame holding is performed by promoting ignition in a recirculation region formed on the downstream side of the first member and the second member to form a flame.

According to the above configuration, the first inclined surface and the second inclined surface are inclined toward one side with respect to the ejection direction, and the first flat surface and the second flat surface are surfaces on the other side in the predetermined direction. doing. Since the second flat surface of the second member is disposed adjacent to the first inclined surface of the first member, the fuel gas guided by the first member is compared to the case where both surfaces are inclined in different directions. Interference between the flow and the fuel gas flow guided by the second member is suppressed. Thereby, it is suppressed that the low-flow-rate recirculation area | region of the downstream of a 1st member and a 2nd member shrinks, and the ignition performance by a flame holder can fully be exhibited.
As described above, according to the combustion burner according to one aspect of the present disclosure, it is possible to improve the ignitability while maintaining the internal flame holding performance.

The combustion burner according to an aspect of the present disclosure includes a plate-like third member that is disposed in the fuel nozzle along the ejection direction and is disposed adjacent to the one side of the second member. The third member is disposed at a central portion in the predetermined direction of the fuel nozzle, and includes a third inclined surface disposed at a downstream end in the ejection direction, and the third inclined surface is disposed on the other side. The structure which is a surface which inclines toward the said other side with respect to the said ejection direction may be sufficient.

According to the combustion burner having the above configuration, the fuel gas is deflected by the third inclined surface of the third member, and the fuel gas flow is separated at the end of the third inclined surface. A fuel gas recirculation zone is formed. Ignition is promoted and a flame is formed in the recirculation region formed on the downstream side of the third member, so that internal flame holding is promoted at the center in the predetermined direction of the combustion burner. In addition, since the first inclined surface of the first member and the second inclined surface of the second member are inclined toward one side of the predetermined direction, that is, the central portion of the combustion burner in the predetermined direction, The fuel concentration in the central portion is increased by the two inclined surfaces, and the ignitability in the central portion is improved.

In the combustion burner configured as described above, a plate-like fourth member disposed in the fuel nozzle along the ejection direction, and disposed in the fuel nozzle along the ejection direction, and the fourth member. A plate-like fifth member disposed adjacent to the other side, and the fourth member is disposed at a fourth inclined surface disposed at a downstream end in the ejection direction and at a downstream end in the ejection direction. A fifth flat surface disposed at the downstream end in the ejection direction, and a fifth flat surface disposed at the downstream end in the ejection direction. The fourth inclined surface and the fifth inclined surface are surfaces facing the other side and inclined toward the other side with respect to the ejection direction, and the fourth flat surface and the fifth inclined surface. The flat surface faces the one side and extends along the ejection direction. The third member is disposed adjacent to the other side of the fifth member, and includes a sixth inclined surface disposed at a downstream end in the ejection direction, and the sixth inclined surface is It may be a surface that faces one side and is inclined toward the one side with respect to the ejection direction.

According to such a combustion burner, the third member is disposed at the center in the predetermined direction of the combustion burner, the second member and the fifth member are disposed adjacent to the third member, and the second member and the fifth member are disposed. A first member and a fourth member are disposed adjacent to each other. Similarly to the first member and the second member, the low flow rate recirculation region on the downstream side of the fourth member and the fifth member is suppressed from being reduced, and the ignition performance by the flame holder can be sufficiently exhibited. . In addition, since the fourth inclined surface of the fourth member and the fifth inclined surface of the fifth member are inclined toward the other side in the predetermined direction, that is, the central portion of the combustion burner in the predetermined direction, The fuel concentration in the central portion is increased by the five inclined surfaces, and the ignitability in the central portion is improved.

The combustion burner according to an aspect of the present disclosure includes a plate-like third member that is disposed in the fuel nozzle along the ejection direction and is disposed adjacent to the one side of the second member. The third member is disposed at a central portion in the predetermined direction of the fuel nozzle, and is disposed at a third inclined surface disposed at the downstream end in the ejection direction and at a downstream end in the ejection direction. 3 flat surfaces, the third inclined surface is a surface that faces the one side and is inclined toward the one side with respect to the ejection direction, and the third flat surface is the other side Further, it may be a surface that extends along the ejection direction and that a flame of another combustion burner is guided from the one side and a furnace wall is disposed on the other side.

According to the combustion burner having the above configuration, the fuel gas is deflected by the third inclined surface of the third member, and the fuel gas flow is separated at the end of the third inclined surface. A fuel gas recirculation zone is formed. Ignition is promoted and a flame is formed in the recirculation region formed on the downstream side of the third member, so that internal flame holding is promoted at the center in the predetermined direction of the combustion burner.

In addition, the fuel gas recirculation region adjacent to the combustion air nozzle on one side in a predetermined direction is formed in a direction approaching the flow of air ejected from the combustion air nozzle, so that the air flow acts to reduce the recirculation region. To do. On the other hand, the fuel gas recirculation region adjacent to the combustion air nozzle on the other side in the predetermined direction is formed in a direction away from the flow of air ejected from the combustion air nozzle, so that the air flow does not act. Do not reduce. Therefore, the recirculation region on one side in the predetermined direction where the heat load due to the flame of the other combustion burner is large is reduced, and the recirculation region on the other side in the predetermined direction where there is no heat load due to the flame of the other combustion burner is expanded, The difference between the thermal loads on one side and the other side in the predetermined direction is reduced to further promote internal flame holding.

In the combustion burner configured as described above, a plate-like fourth member disposed in the fuel nozzle along the ejection direction, and disposed in the fuel nozzle along the ejection direction, and the fourth member. A plate-like fifth member disposed adjacent to the other side, and the fourth member is disposed at a fourth inclined surface disposed at a downstream end in the ejection direction and at a downstream end in the ejection direction. A fifth flat surface disposed at the downstream end in the ejection direction, and a fifth flat surface disposed at the downstream end in the ejection direction. The fourth inclined surface and the fifth inclined surface are surfaces facing the one side and inclined toward the one side with respect to the ejection direction, and the fourth flat surface and the fifth inclined surface. The flat surface faces the other side and extends along the ejection direction The third member is disposed adjacent to the other side of the fifth member, and includes a sixth inclined surface disposed at a downstream end in the ejection direction, and the sixth inclined surface is It may be a surface that faces one side and is inclined toward the one side with respect to the ejection direction.

According to such a combustion burner, the third member is disposed at the center in the predetermined direction of the combustion burner, the second member and the fifth member are disposed adjacent to the third member, and the second member and the fifth member are disposed. A first member and a fourth member are disposed adjacent to each other. Similar to the first member and the second member, the reduction of the low flow velocity region on the downstream side of the fourth member and the fifth member is suppressed, and the ignition performance by the flame holder can be sufficiently exhibited.

The combustion burner which concerns on 1 aspect of this indication WHEREIN: It is good also as a structure which ejects air in the direction inclined toward the said one side with respect to the said ejection direction in the said one side edge part.
According to the combustion burner of this configuration, the flow of air ejected from the combustion air nozzle is away from the fuel gas recirculation region adjacent to the combustion air nozzle on one side in a predetermined direction, and the recirculation region is reduced. Is suppressed.

In the combustion burner having the above-described configuration, the combustion air nozzle may eject air in a direction inclined toward the one side with respect to the ejection direction at the other end portion.
According to such a combustion burner, the flow of air ejected from the combustion air nozzle is in a direction along the recirculation region of the fuel gas adjacent to the combustion air nozzle on the other side in the predetermined direction, and appropriate ignition and Internal flame holding can be performed.

In the combustion burner according to an aspect of the present disclosure, the position of the downstream end of the first member in the ejection direction may be different from the position of the downstream end of the second member in the ejection direction.
Since the position of the downstream end of the ejection direction of the first member is different from the position of the downstream end of the ejection direction of the second member, the first inclined surface of the first member and the second flat surface of the second member are close to each other and the fuel gas An increase in the flow rate of the is suppressed. As a result, flame blowing due to an increase in the flow rate of the fuel gas is suppressed, and stable flame holding becomes possible.

In the combustion burner according to one aspect of the present disclosure, the position of the downstream end of the first member in the ejection direction and the position of the downstream end of the second member in the ejection direction may be the same position.
Since the position of the downstream end in the ejection direction of the first member and the position of the downstream end in the ejection direction of the second member are the same position, they are arranged on the upstream side compared to the case where they are arranged at different positions in the ejection direction. The recirculation region formed by the member is hardly crushed by the recirculation region where the member disposed downstream is formed, and a wide recirculation region can be secured.

A boiler according to an aspect of the present invention includes a furnace having a hollow shape and installed in a vertical direction, any one of the combustion burners disposed in the furnace, and smoke disposed in an upper portion of the furnace. Having a road.
According to the boiler which concerns on 1 aspect of this invention, ignitability can be improved, maintaining internal flame holding performance.

In the boiler according to one aspect of the present invention, an additional air supply unit may be provided above the combustion burner of the furnace.

According to the present invention, it is possible to provide a combustion burner and a boiler with improved ignitability while maintaining internal flame holding performance.

It is a schematic structure figure showing a coal burning boiler of a 1st embodiment. It is a top view showing the arrangement configuration of a combustion burner. It is the front view which looked at the combustion burner of a 1st embodiment from the furnace. It is a longitudinal cross-sectional view of the combustion burner of 1st Embodiment. It is the elements on larger scale of the internal member of the combustion burner shown in FIG. It is the elements on larger scale of the internal member of the combustion burner of a 1st modification. It is the elements on larger scale of the internal member of the combustion burner of a 2nd modification. It is a longitudinal cross-sectional view of the combustion burner of 2nd Embodiment. It is the elements on larger scale of the internal member of the combustion burner shown in FIG. It is the elements on larger scale of the internal member of the combustion burner of a modification.

Hereinafter, an embodiment of a combustion burner and a boiler according to some embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment, and when there are two or more embodiments, what comprises combining each embodiment is also included.

[First Embodiment]
FIG. 1 is a schematic configuration diagram illustrating a coal fired boiler according to the first embodiment, and FIG. 2 is a plan view illustrating an arrangement configuration of combustion burners.

The boiler according to the first embodiment uses pulverized coal obtained by pulverizing coal as pulverized fuel (solid fuel), burns the pulverized coal with a combustion burner, and recovers the heat generated by the combustion. It is a boiler.

In the first embodiment, as shown in FIG. 1, the coal fired boiler 10 is a conventional boiler, and includes a furnace 11, a combustion device 12, and a flue 13. The furnace 11 has a rectangular hollow shape and is installed along the vertical direction. A furnace wall 11a constituting the furnace 11 is constituted by a heat transfer tube.

The combustion apparatus 12 is provided in the lower part of the furnace wall (heat-transfer tube) 11a which comprises this furnace 11. FIG. 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 five sets along the vertical direction. Five stages are arranged. However, the shape of the furnace, the number of combustion burners in one stage, and the number of stages are not limited to this embodiment.

The combustion burners 21, 22, 23, 24, 25 are connected to pulverizers (pulverized coal machines) 31, 32, 33, 34, 35 via pulverized coal supply pipes 26, 27, 28, 29, 30. ing. Although not shown, the pulverizers 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 a plurality of pulverization rollers are provided above the pulverization table. Is supported rotatably in conjunction with the rotation of the grinding table. Accordingly, when coal is introduced between a plurality of crushing rollers and a crushing table, the pulverized coal supplied to the pulverized coal supply pipe 26 is pulverized to a predetermined size and classified by transporting air (primary air). 27, 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 supply unit (hereinafter referred to as an additional air nozzle) 39 above the mounting positions of the combustion burners 21, 22, 23, 24, 25. The end of the branched air duct 40 branched from the air duct 37 is connected to the air duct 37. Therefore, combustion air (fuel gas combustion air / secondary air) sent by the blower 38 is supplied from the air duct 37 to the wind box 36, and the combustion burners 21, 22, 23, 24, The combustion air (additional air) sent by the blower 38 can be supplied from the branch air duct 40 to the additional air nozzle 39.

The flue 13 is connected to the upper part of the furnace 11. The flue 13 is provided with superheaters (super heaters) 51, 52, 53, reheaters (reheaters) 54, 55, and economizers 56, 57 for recovering the heat of exhaust gas. Heat exchange is performed between the exhaust gas generated by the combustion in the furnace 11 and the water.

The flue 13 is connected to a gas duct 58 to which exhaust gas subjected to heat exchange is discharged downstream. The gas duct 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 gas duct 58, and the combustion burners 21, 22, 23, 24, The temperature of the combustion air supplied to 25 can be raised.

Although not shown, the gas duct 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.

Here, although the combustion apparatus 12 is demonstrated in detail, since the combustion burners 21, 22, 23, 24, and 25 which comprise this combustion apparatus 12 have comprised the substantially the same structure, respectively, the combustion burner 21 is represented. To explain.

As shown in FIG. 2, the combustion burner 21 includes combustion burners 21 a, 21 b, 21 c, and 21 d provided on four furnace walls 11 a 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 blows a pulverized coal mixture (fuel gas) in which pulverized coal and carrier air are mixed into the furnace 11, and burns outside the pulverized coal mixture. Blowing air (fuel gas combustion air / secondary air). Then, by igniting this pulverized coal mixture, four flames F1, F2, F3, F4 can be formed, and these flames F1, F2, F3, F4 are viewed from above the furnace 11 (see FIG. 2) A flame swirl flow C swirling counterclockwise.

When the pulverizers 31, 32, 33, 34, and 35 are driven in the coal fired boiler 10 configured as described above, solid fuel is pulverized and pulverized coal is transported air as shown in FIGS. 1 and 2. At the same time, the pulverized coal supply pipes 26, 27, 28, 29, and 30 are supplied to the combustion burners 21, 22, 23, 24, and 25, respectively. On the other hand, the heated combustion air is supplied from the air duct 37 to the combustion burners 21, 22, 23, 24, and 25 through the wind box 36 and is supplied from the branch air duct 40 to the additional air nozzle 39. The Then, the combustion burners 21, 22, 23, 24, and 25 blow a pulverized coal mixture, which is a mixture of pulverized coal and carrier air, into the furnace 11 and blow 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 coal mixture and the combustion air are burned to generate a flame. When a flame is generated in the lower part of the furnace 11, the combustion gas (exhaust gas) rises in the furnace 11, and the flue 13 is discharged.

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

The water supplied from a water supply pump (not shown) is preheated by the economizers 56 and 57, and then heated while being supplied to a steam drum (not shown) and supplied to each water pipe (not shown) on the furnace wall. Then, it becomes saturated steam and is sent to a steam drum (not shown). Further, saturated steam of a steam drum (not shown) is introduced into the superheaters 51, 52, and 53 and is heated by the combustion gas. The superheated steam generated by the superheaters 51, 52, 53 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 54 and 55, 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 56 and 57 of the flue 13 is subjected to removal of harmful substances such as NOx by a catalyst in a denitration apparatus (not shown) in a gas duct 58, and particulate matter is removed by an electric dust collector. After the sulfur content is removed by the desulfurization device, it is discharged from the chimney into the atmosphere.

Here, the combustion burner 21 (21a, 21b, 21c, 21d) configured in this manner will be described in detail. FIG. 3 is a front view of the combustion burner 21 according to the first embodiment as viewed from the furnace 11, and FIG. 4 is a longitudinal section (II section in FIG. 3) of the combustion burner 21.

As shown in FIGS. 3 and 4, the combustion burner 21 includes a fuel nozzle 61, a combustion air nozzle 62, and a secondary air nozzle 63 provided from the center side, and an internal member 64 provided in the fuel nozzle 61. It has been.

The fuel nozzle 61 is capable of ejecting a pulverized fuel mixture (hereinafter referred to as fuel gas) 301 obtained by mixing pulverized coal (solid fuel) and carrier air (primary air). The combustion air nozzle 62 is disposed outside the fuel nozzle 61 and can eject part of the combustion air (fuel gas combustion air) 302 to the outer peripheral side of the fuel gas 301 ejected from the fuel nozzle 61. is there. The secondary air nozzle 63 is disposed outside the combustion air nozzle 62, and a part of the combustion air (hereinafter referred to as secondary air) on the outer peripheral side of the fuel gas combustion air 302 ejected from the combustion air nozzle 62. 303 can be ejected.

The internal member 64 is disposed in the fuel nozzle 61 at the tip of the fuel nozzle 61, that is, on the downstream side in the flow direction of the fuel gas 301, so that the fuel gas 301 is ignited and flame-holding or fuel. It functions as a guide member. The internal member 64 includes a first member 71, a second member 72, a third member 73, a fourth member 74, and a fifth member 75. The first member 71, the second member 72, the third member 73, the fourth member 74, and the fifth member 75 are arranged along the vertical direction and are arranged in the horizontal direction Hd with a predetermined interval. It is a member. In this case, the vertical direction includes a direction shifted by a minute angle with respect to the vertical direction.

As shown in FIG. 3, when the combustion burner 21 is viewed from the furnace 11, the flames of the other combustion burners 21 are guided from the right side in the horizontal direction Hd, and the furnace wall 11a is formed on the left side in the horizontal direction Hd. Be placed. Hereinafter, the right side in the horizontal direction Hd is referred to as the adjacent burner side (one side) Bs, and the left side in the horizontal direction is referred to as the furnace wall side (the other side) Fs.

The first member 71 is a tip portion of the fuel nozzle 61, and is horizontal with respect to an axis (center line of the fuel nozzle 61) O along the jet direction Jd of the fuel gas 301 (a direction perpendicular to the jet direction Jd) Hd. Is disposed on the furnace wall side Fs. The first member 71 is disposed adjacent to the inner wall surface 61 a of the fuel nozzle 61 on the furnace wall side Fs with a predetermined interval (gap) therebetween, and is a plate along the vertical direction and along the ejection direction Jd of the fuel gas 301. It has a shape.

The second member 72 is the tip of the fuel nozzle 61 and is disposed on the furnace wall side Fs in the horizontal direction Hd with respect to the axis O along the jet direction Jd of the fuel gas 301. The second member 72 is disposed adjacent to the first member 71 at a predetermined interval on the adjacent burner side Bs in the horizontal direction Hd, and is a plate along the vertical direction and along the ejection direction Jd of the fuel gas 301. It has a shape.

The third member 73 is the tip of the fuel nozzle 61 and is disposed at the center in the horizontal direction Hd of the fuel nozzle 61 on the axis O along the jet direction of the fuel gas 301. The third member 73 is disposed adjacent to the adjacent burner side Bs in the horizontal direction Hd from the second member 72 with a predetermined interval. The third member 73 has a plate shape along the vertical direction and along the ejection direction Jd of the fuel gas 301.

4th member 74 is the front-end | tip part of the fuel nozzle 61, Comprising: It arrange | positions at the adjacent burner side Bs of the horizontal direction Hd with respect to the axis line O along the injection direction Jd of the fuel gas 301. FIG. The fourth member 74 is disposed at a predetermined interval from the inner wall surface 61 a on the adjacent burner side Bs of the fuel nozzle 61, and has a plate shape along the vertical direction and along the ejection direction Jd of the fuel gas 301.

The fifth member 75 is the tip of the fuel nozzle 61 and is disposed on the adjacent burner side Bs in the horizontal direction Hd with respect to the axis O along the jet direction Jd of the fuel gas 301. The fifth member 75 is adjacent to the fourth member 74 at a predetermined interval (gap) on the furnace wall side Fs in the horizontal direction Hd, and at a predetermined interval on the adjacent burner side Bs with respect to the third member 73. Are arranged adjacent to each other, and have a plate shape along the vertical direction and along the ejection direction Jd of the fuel gas 301.

The fuel nozzle 61 and the combustion air nozzle 62 have a long tubular structure. The fuel nozzle 61 has a fuel gas flow path P1 that extends in the longitudinal direction and has the same flow path cross-sectional shape by four flat inner wall surfaces 61a, and has a rectangular shape at the tip (downstream end). The opening 61b is provided. The combustion air nozzle 62 extends in the longitudinal direction by the four flat outer wall surfaces 61c and the four flat inner wall surfaces 62a of the fuel nozzle 61, and has the same flow path cross-sectional shape. A rectangular ring-shaped opening 62b is provided at the tip (downstream end). Therefore, the fuel nozzle 61 and the combustion air nozzle 62 have a double tubular structure.

The secondary air nozzle 63 has a long tubular structure disposed outside the fuel nozzle 61 and the combustion air nozzle 62. The secondary air nozzle 63 has a tubular structure having four rectangular cross-sectional shapes, and the secondary air nozzle bodies 63a, 63b, which are disposed independently above, below, left, and right of the combustion air nozzle 62, respectively. 63c and 63d, which are arranged outside the combustion air nozzle 62 with a predetermined gap. The secondary air nozzle 63 includes four secondary air flow paths P31, P32, P33 extending in the longitudinal direction and having the same flow path cross-sectional shape by four secondary air nozzle bodies 63a, 63b, 63c, 63d. , P34, and a rectangular ring-shaped opening 63e is provided at the tip (downstream end).

In addition, the shape of the fuel nozzle 61 and the combustion air nozzle 62 is not limited to a square, and may be a rectangle. In this case, the corner may be curved. By using a tubular structure with a curved corner, the strength of the nozzle can be improved. Furthermore, it is good also as a cylinder.

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

The secondary air nozzle 63 may not be constituted by the four secondary air nozzle bodies 63a, 63b, 63c, 63d, but may be arranged in a rectangular shape as a double tubular structure outside the combustion air nozzle 62. Good. The secondary air nozzle 63 is composed of the secondary air nozzle bodies 63a, 63b, 63c, and 63d, but only the upper and lower secondary air nozzle bodies 63a and 63b, or the left and right secondary air nozzle bodies 63c and 63d. Or just. Further, the secondary air nozzle 63 may be capable of adjusting the ejection amount of the secondary air 303 by providing a damper opening adjustment mechanism or the like in each of the secondary air nozzle bodies 63a, 63b, 63c, and 63d.

The first member 71 is provided integrally with a flat portion 71a having a constant width and a front end portion (downstream end portion in the flow direction of the fuel gas 301) of the flat portion 71a in a horizontal cross-sectional shape (FIG. 2). And a widened portion 71b. The flat portion 71a has a constant width along the ejection direction Jd of the fuel gas 301. The widened portion 71b is disposed at the downstream end in the ejection direction Jd of the fuel gas 301 and increases in width toward the downstream side in the ejection direction Jd. The widened portion 71b has a substantially right triangle shape in horizontal cross section, a base end portion is connected to the flat portion 71a, a distal end portion becomes wider toward the downstream side in the ejection direction Jd of the fuel gas 301, and a front end is formed. The fuel gas 301 has a plane perpendicular to the jet direction Jd.

The widened portion 71b has an inclined surface (first inclined surface) 71c facing the adjacent burner side Bs in the horizontal direction Hd and inclined toward the adjacent burner side Bs with respect to the ejection direction Jd, and the furnace wall side in the horizontal direction Hd It has a flat surface (first flat surface) 71d that faces Fs and extends along the ejection direction Jd, and an end surface (first end surface) 71e on the front end side. A corner formed by the inclined surface 71c and the end surface 71e becomes an inclination end end (first inclination end end) at which the inclination of the inclined surface 71c ends, and the fuel gas flow is separated at the inclination end end.
The width of the widened portion 71b is constant along the longitudinal direction (vertical direction), but the width may be varied. In addition, the inclined surface 71c and the end surface 71e are desirably flat surfaces, but may be surfaces that are bent or curved in a concave shape or a convex shape. Moreover, although the horizontal cross section of the widened part 71b is made into the substantially right triangle, it is not limited to this, The shape where the end surface 71e was dented or the shape which bent the plate-shaped body may be sufficient.

The second member 72 has a flat portion 72a having a constant width in a cross-sectional shape (FIG. 2) cut along the horizontal direction, and a front end portion (downstream end portion in the flow direction of the fuel gas 301) of the flat portion 72a. And a widened portion 72b provided integrally therewith. The flat portion 72a has a constant width along the ejection direction Jd of the fuel gas 301. The width of the widened portion 72b increases toward the ejection direction Jd of the fuel gas 301. The widened portion 72b has a substantially right triangle shape in horizontal cross section, the base end portion is connected to the flat portion 72a, the tip end portion becomes wider toward the downstream side in the jet direction Jd of the fuel gas 301, and the front end is The fuel gas 301 has a plane perpendicular to the jet direction Jd.

The widened portion 72b has an inclined surface (second inclined surface) 72c facing the adjacent burner side Bs in the horizontal direction Hd and inclined toward the adjacent burner side Bs with respect to the ejection direction Jd, and the furnace wall side in the horizontal direction Hd It has a flat surface (second flat surface) 72d that faces Fs and extends along the ejection direction Jd, and an end surface (second end surface) 72e on the front end side. A corner formed by the inclined surface 72c and the end surface 72e becomes an inclination end end (second inclination end end) at which the inclination of the inclined surface 72c ends, and the fuel gas flow is separated at the inclination end end.
Although the width of the widened portion 72b is constant along the longitudinal direction (vertical direction), the width may be varied. The inclined surface 72c and the end surface 72e are preferably flat surfaces, but may be surfaces that are bent or curved in a concave or convex shape. Moreover, although the horizontal cross section of the widened part 72b is made into the substantially right triangle, it is not limited to this, The shape where the end surface 72e was dented or the shape which bent the plate-shaped body may be sufficient.

The third member 73 is provided integrally with a flat portion 73a having a constant width and a front end portion (downstream end portion in the flow direction of the fuel gas 301) of the flat portion 73a in a horizontal sectional shape (FIG. 2). And a widened portion 73b. The flat portion 73a has a constant width along the ejection direction Jd of the fuel gas 301. The width of the widened portion 73b increases toward the ejection direction Jd of the fuel gas 301. The widened portion 73b has a substantially isosceles triangular horizontal cross section, a base end portion is connected to the flat portion 73a, a tip end portion becomes wider toward the downstream side in the ejection direction Jd of the fuel gas 301, and the front end Is a plane orthogonal to the jet direction Jd of the fuel gas 301.

The widened portion 73b faces the adjacent burner side Bs and inclines toward the adjacent burner side Bs with respect to the ejection direction Jd (sixth inclined surface) 73c, faces the furnace wall side Fs and ejects in the ejection direction Jd. On the other hand, it has an inclined surface (third inclined surface) 73d inclined toward the furnace wall side Fs and an end surface 73e on the front end side. The corner portion formed by the inclined surface 73c and the end surface 73e and the corner portion formed by the inclined surface 73d and the end surface 73e become an inclination end end (third inclination end end) at which the inclination of the inclined surfaces 73c and 73d ends. The fuel gas flow is separated at the end of inclination.
The width of the widened portion 73b is constant along the longitudinal direction (vertical direction), but the width may be varied. The inclined surface 73c, the inclined surface 73d, and the end surface 73e are preferably flat surfaces, but may be surfaces that are bent or curved in a concave shape or a convex shape. Moreover, although the horizontal cross section of the widened part 73b is made into the substantially isosceles triangle, it is not limited to this, The shape with which the end surface 73e was dented, and Y shape may be sufficient.

The fourth member 74 is provided integrally with a flat portion 74a having a constant width and a front end portion (downstream end portion in the flow direction of the fuel gas 301) of the flat portion 74a in a horizontal sectional shape (FIG. 2). And a widened portion 74b. The flat portion 74a has a constant width along the ejection direction Jd of the fuel gas 301. The widened portion 74b is disposed at the downstream end in the ejection direction Jd of the fuel gas 301 and increases in width toward the downstream side in the ejection direction Jd. The widened portion 74b has a substantially right triangle shape in horizontal cross section, the base end portion is connected to the flat portion 74a, the tip end portion becomes wider toward the downstream side in the ejection direction Jd of the fuel gas 301, and the front end is The fuel gas 301 has a plane perpendicular to the jet direction Jd.

The widened portion 74b has an inclined surface (fourth inclined surface) 74c facing the furnace wall side Fs in the horizontal direction Hd and inclined toward the furnace wall side Fs with respect to the ejection direction Jd, and an adjacent burner side in the horizontal direction Hd. It has a flat surface (fourth flat surface) 74d that faces Bs and extends along the ejection direction Jd, and an end surface (fourth end surface) 74e on the front end side. A corner formed by the inclined surface 74c and the end surface 74e becomes an inclination end end (fourth inclination end end) at which the inclination of the inclined surface 74c ends, and the fuel gas flow is separated at the inclination end end.
The width of the widened portion 74b is constant along the longitudinal direction (vertical direction), but the width may be varied. In addition, the inclined surface 74c and the end surface 74e are preferably flat surfaces, but may be surfaces that are bent or curved in a concave shape or a convex shape. Moreover, although the horizontal cross section of the widened part 74b is made into the substantially right triangle, it is not limited to this, The shape where the end surface 74e was dented or the shape which bent the plate-shaped object may be sufficient.

The fifth member 75 has a cross-sectional shape cut along the horizontal direction (FIG. 2), a flat portion 75a having a constant width, and a front end portion (downstream end portion in the flow direction of the fuel gas 301) of the flat portion 75a. And a widened portion 75b provided integrally therewith. The flat portion 75a has a constant width along the ejection direction Jd of the fuel gas 301. The width of the widened portion 75b increases toward the ejection direction Jd of the fuel gas 301. The widened portion 75b has a substantially right triangle shape in horizontal cross section, the base end portion is connected to the flat portion 75a, the tip end portion becomes wider toward the downstream side in the ejection direction Jd of the fuel gas 301, and the front end is The fuel gas 301 has a plane perpendicular to the jet direction Jd.

The widened portion 75b has an inclined surface (fifth inclined surface) 75c that faces the furnace wall side Fs in the horizontal direction Hd and is inclined toward the furnace wall side Fs with respect to the ejection direction Jd, and an adjacent burner side in the horizontal direction Hd. It has a flat surface (fifth flat surface) 75d that faces Bs and extends along the ejection direction Jd, and an end surface (fifth end surface) 75e on the front end side. A corner formed by the inclined surface 75c and the end surface 75e becomes an inclination end end (fifth inclination end end) at which the inclination of the inclined surface 75c ends, and the fuel gas flow is separated at the inclination end end.
The width of the widened portion 75b is constant along the longitudinal direction (vertical direction), but the width may be varied. In addition, the inclined surface 75c and the end surface 75e are desirably flat surfaces, but may be surfaces that are bent or curved in a concave shape or a convex shape. Moreover, although the horizontal cross section of the widened part 75b is made into the substantially right triangle, it is not limited to this, The shape where the end surface 75e was dented or the shape which bent the plate-shaped object may be sufficient.

As described above, the first member 71, the second member 72, the third member 73, the fourth member 74, the fifth member 75, and the inner wall surface of the fuel nozzle 61 are arranged with a predetermined gap therebetween. . The predetermined interval is at least a gap larger than the width of the widened portion 71b, 72b, 73b, 74b, 75b in each member 71, 72, 73, 74, 75, or at least each member 71, 72, 73, 74, 75. The widened portions 71b, 72b, 73b, 74b, and 75b in FIG. 5 are gaps that do not interfere (contact) with each other or the inner wall surface 61a of the fuel nozzle 61 due to thermal expansion.

In the fuel nozzle 61, first to fifth members 71, 72, 73, 74, and 75 are disposed in the horizontal direction Hd at predetermined intervals as the internal member 64 inside. And the 1st member 71, the 3rd member 73, and the 4th member 74 are provided with the wide part 71b, 73b, 74b at the front-end | tip part, respectively. The widened portions 71b, 73b, and 74b are arranged so that the end surfaces 71e, 73e, and 74e are aligned on the same surface at the same position in the opening 61b of the fuel nozzle 61 and the ejection direction Jd of the fuel gas 301. On the other hand, the second member 72 and the fifth member 75 are provided with widened portions 72 b and 75 b at the front end portions thereof, and the widened portions 72 b and 75 b have the end surfaces 72 e and 75 e that are fuel gas from the opening 61 b of the fuel nozzle 61. It is arrange | positioned in the upstream of the ejection direction of 301. FIG.

That is, the first member 71, the third member 73, and the fourth member 74 are arranged such that the end surfaces 71e, 73e, and 74e of the widened portions 71b, 73b, and 74b and the opening 61b of the fuel nozzle 61 in the jet direction Jd of the fuel gas 301. Are in the same position. On the other hand, in the second member 72 and the fifth member 75, the end surfaces 72e and 75e of the widened portions 72b and 75b are separated from the opening 61b of the fuel nozzle 61 by a predetermined distance L on the upstream side in the ejection direction Jd of the fuel gas 301. It is arranged at the position.

The first member 71, the second member 72, the third member 73, the fourth member 74, and the fifth member 75 have rear upper ends and lower ends on the inner wall surface 61 a of the fuel nozzle 61 via support members 87 and 88. It is supported. The support members 87 and 88 are fixed to the upper and lower portions of the inner wall surface 61a of the fuel nozzle 61, and the upper and lower ends of the first to fifth members 71, 72, 73, 74, and 75 are the support members. 87, 88.

In this case, the first to fifth members 71, 72, 73, 74, 75 are fixed to support members 87, 88 fixed to the inner wall surface 61 a of the fuel nozzle 61. However, it is not limited to this configuration. For example, the second member 72 and the fifth member 75 are disposed at positions where the end surfaces 72e and 75e of the widened portions 72b and 75b are retracted by a predetermined distance L from the opening 61b of the fuel nozzle 61. It is conceivable that the positions of the widened portions 72b and 75b change the predetermined distance L in accordance with the type of fuel and the amount of ejection. Therefore, it is desirable to provide a position adjustment mechanism (not shown) that allows the second member 72 and the fifth member 75 to be adjusted in position along the ejection direction Jd of the fuel gas 301.

In the fuel nozzle 61, since the first to fifth members 71, 72, 73, 74, and 75 are supported by the support members 87 and 88 as the internal member 64, the fuel gas flow path P1 is divided into six regions. Will be. That is, the fuel gas flow path P1 includes a fuel gas flow path P11 between the first member 71 and the second member 72, a fuel gas flow path P12 between the second member 72 and the third member 73, and a fourth member. 74, a fuel gas flow path P13 between the fifth member 75, a fuel gas flow path P14 between the fifth member 75 and the third member 73, and a fuel gas flow path between the first member 71 and the inner wall surface 61a. P15 is divided into a fuel gas flow path P16 between the fourth member 74 and the inner wall surface 61a.

In the combustion burner 21 configured as described above, the fuel gas (pulverized coal and primary air) 301 flows through the fuel gas flow path P1 of the fuel nozzle 61 and is ejected into the furnace 11 from the opening 61b. The fuel gas combustion air 302 flows through the combustion air flow path P <b> 2 of the combustion air nozzle 62 and is ejected from the opening 62 b to the outside of the fuel gas 301. The secondary air 303 flows through the secondary air flow path P3 of the secondary air nozzle 63, and is jetted out of the combustion gas 301 combustion air from the opening 63e. At this time, the fuel gas (pulverized coal and primary air) 301, the fuel gas combustion air 302, and the secondary air 303 are ejected as a straight flow along the burner axial direction (axis O) without swirling.

At this time, the fuel gas 301 branches and flows through the first to fifth members 71, 72, 73, 74, and 75 at the opening 61b of the fuel nozzle 61, where it is ignited and burned. Become. In addition, combustion of the fuel gas 301 is promoted by jetting the fuel gas combustion air 302 to the outer periphery of the fuel gas 301. Furthermore, since the secondary air 303 is ejected to the outer periphery of the combustion flame, the ratio of the fuel gas combustion air 302 and the secondary air 303 can be adjusted, and optimal combustion can be obtained.

Further, the widened portions 72b and 75b of the second member 72 and the fifth member 75 are arranged in the jet direction Jd of the fuel gas 301 from the widened portions 71b, 73b and 74b of the first member 71, the third member 73 and the fourth member 74. Arranged upstream. For this reason, the position where the fuel gas flow path P1 of the fuel nozzle 61 is closed shifts in the jet direction Jd of the fuel gas 301, the area where the flow path sharply narrows decreases, and at the positions of the widened portions 71b, 73b, 74b. The flow rate of the fuel gas 301 is reduced. Therefore, internal ignition and internal flame holding can be strengthened without increasing the size of the fuel nozzle 61.

As described above, the widened portions 71b, 72b, 73b, 74b, and 75b of the first to fifth members 71, 72, 73, 74, and 75 are disposed at different positions in the fuel gas ejection direction Jd. ~ When the flow rates of the fuel gas 301 in the widened portions 71b, 72b, 73b, 74b, 75b of the fifth members 71, 72, 73, 74, 75 are arranged at the same position in the ejection direction Jd. It can be reduced as compared.

Next, referring to FIG. 5, the recirculation regions Rz1, Rz2, Rz3 formed by the widened portions 71b, 72b, 73b, 74b, 75b of the first to fifth members 71, 72, 73, 74, 75. Rz4 will be described. FIG. 5 is a partially enlarged view of the internal member 64 of the combustion burner 21 shown in FIG. The recirculation regions Rz1, Rz2, Rz3, Rz4, and Rz5 are formed in front of the end surfaces 71e, 72e, 73e, 74e, and 75e (see FIG. 4) of the first to fifth members 71, 72, 73, 74, and 75, respectively. It is an area to be done. The arrows shown in FIG. 5 indicate the flow of the fuel gas 301 separated at the downstream ends of the first to fifth members 71, 72, 73, 74, 75.

As shown in FIG. 5, the inner member 64 is a fuel because the widened portions 71b, 72b, 73b, 74b, and 75b of the first to fifth members 71, 72, 73, 74, and 75 have a split shape. As the gas 301 flows along the inclined surfaces 71c, 72c, 73c, 73d, 74c, and 75c of the widened portions 71b, 72b, 73b, 74b, and 75b, and wraps around the end surfaces 71e, 72e, 73e, 74e, and 75e, Recirculation regions Rz1, Rz2, Rz3, Rz4, and Rz5 are formed in front of the end faces 71e, 72e, 73e, 74e, and 75e.

The fuel gas 301 is ignited and held in the recirculation regions Rz1, Rz2, Rz3, Rz4, and Rz5, and the internal flame of the combustion flame (flame holding in the central region on the axis O side in the fuel nozzle 61). Is realized. Then, the high temperature of the outer peripheral portion of the combustion flame can be reduced, and the amount of NOx generated in the outer peripheral portion of the combustion flame in a high oxygen atmosphere is reduced by the secondary air 303.

In the fuel gas 301, first, recirculation regions Rz2 and Rz5 are formed by the inclined surfaces 72c and 75c in the widened portions 72b and 75b of the second member 72 and the fifth member 75, respectively. Then, after the recirculation region is formed by the inclined surfaces 72c and 75c in the wide portions 72b and 75b of the second member 72 and the fifth member 75, the fuel gas 301 is then moved to the first member 71 and the third member. 73, the recirculation regions Rz1, Rz3, Rz4 are formed by the inclined surfaces 71c, 73c, 73d, 74c in the widened portions 71b, 73b, 74b of the fourth member 74.

As shown in FIG. 5, the inclined surface 71c of the first member 71 and the inclined surface 72c of the second member 72 are inclined toward the adjacent burner side Bs with respect to the ejection direction Jd, and the flat surface 71d and the flat surface 72d. Faces the furnace wall side Fs in the horizontal direction Hd. Since the flat surface 72d of the second member 72 is disposed adjacent to the inclined surface 71c of the first member 71, interference between the recirculation region Rz1 and the recirculation region Rz2 is suppressed. Thereby, it is suppressed that recirculation area | region Rz1 and recirculation area | region Rz2 shrink | contract, the flame holding performance by the 1st member 71 and the 2nd member 72 is stabilized, and it can fully exhibit ignition performance.

Similarly, the inclined surface 74c of the fourth member 74 and the inclined surface 75c of the fifth member 75 are inclined toward the furnace wall side Fs with respect to the ejection direction Jd, and the flat surface 74d and the flat surface 74d are in the horizontal direction Hd. Facing the adjacent burner side Bs. Since the flat surface 75d of the fifth member 75 is disposed adjacent to the inclined surface 74c of the fourth member 74, interference between the recirculation region Rz4 and the recirculation region Rz5 is suppressed. Thereby, it is suppressed that recirculation area | region Rz4 and recirculation area | region Rz5 shrink | contract, the flame holding performance by the 4th member 74 and the 5th member 75 is stabilized, and ignition performance can fully be exhibited.

Here, the inclined surface 72c of the second member 72 is inclined toward the adjacent burner side Bs with respect to the ejection direction Jd, and the inclined surface 73d of the third member 73 is directed to the furnace wall side Fs with respect to the ejection direction Jd. Inclined towards. Therefore, the recirculation region Rz2 and the recirculation region Rz3 interfere with each other. Further, the inclined surface 75c of the fifth member 75 is inclined toward the furnace wall side Fs with respect to the ejection direction Jd, and the inclined surface 73c of the third member 73 is directed toward the adjacent burner side Bs with respect to the ejection direction Jd. Is inclined. Therefore, the recirculation region Rz5 and the recirculation region Rz3 interfere with each other.

Thus, although the recirculation regions Rz2 and Rz5 interfere with the recirculation region Rz3, the pulverized coal guided by the inclined surfaces 72c and 75c flows into the inclined surfaces 73d and 73c on the downstream side. Therefore, the concentration of the pulverized coal in the central region on the axis O side in the fuel nozzle 61 is increased, and the concentration of the pulverized coal outside the central region is decreased, so that internal ignition and internal flame holding can be enhanced.

Furthermore, the widened portion 71b of the first member 71 has an inclined surface 71c only on the adjacent burner side Bs, and the furnace wall side Fs has a flat surface 71d. Therefore, the fuel gas flow path P15 between the inner wall surface 61a of the fuel nozzle 61 and the first member 71 does not have a flame holding function, so that no recirculation region is formed, and the occurrence of external ignition is suppressed.

Further, the secondary air nozzle 63 ejects the secondary air 303 so as to surround not only from the top and bottom of the fuel nozzle 61 but also from the left and right. Therefore, it becomes difficult to form a partial high-temperature high-oxygen region in the circumferential direction, the oxygen concentration is made uniform in the circumferential direction, and the amount of NOx generated in the outer peripheral portion of the combustion flame is reduced.

The internal member 64 of the combustion burner 21 shown in FIGS. 3 to 5 has the second member 72 and the fifth member 75 arranged on both sides of the third member 73 in the horizontal direction Hd, and the second member 72 and the fifth member 75. Although the 1st member 71 and the 4th member 74 are arrange | positioned on both sides of this and 5 members are arrange | positioned in total, another aspect may be sufficient.

For example, like the internal member 64A of the combustion burner 21A of the first modification shown in FIG. 6, the sixth member 76 and the seventh member 77 are further provided on both sides of the first member 71 and the fourth member 74 in the horizontal direction Hd. A total of seven members may be arranged. A recirculation region Rz6 is formed at the downstream end of the sixth member 76, and a recirculation region Rz7 is formed at the downstream end of the seventh member 77. Here, the shape of the sixth member 76 is the same as the shape of the second member 72, and the shape of the seventh member 77 is the same as the shape of the fifth member 75.

According to this modification, of the seven recirculation regions Rz1, Rz2, Rz3, Rz4, Rz5, Rz6, Rz7 formed by the first to seventh members 71, 72, 73, 74, 75, 76, 77. The recirculation regions Rz1, Rz4, Rz6, Rz7 on the end side in the horizontal direction Hd do not interfere with other recirculation regions. Therefore, the ratio of interference of the recirculation region in the entire combustion burner 21A is reduced, and the reduction in ignitability due to interference is reduced.

The inner member 64 of the combustion burner 21 shown in FIGS. 3 to 5 has end faces 71e, 73e, and 74e of the first member 71, the third member 73, and the fourth member 74 disposed in the opening 61b of the fuel nozzle 61, The end surfaces 72e and 75e of the second member 72 and the fifth member 75 are disposed at positions separated by a predetermined distance L upstream of the opening 61b in the jet direction Jd of the fuel gas 301. It may be.

For example, like the internal member 64B of the combustion burner 21B of the second modified example shown in FIG. 7, the end surfaces 72e and 75e of the second member 72 and the fifth member 75 are arranged in the opening 61b of the fuel nozzle 61, and the opening The end surfaces 71e, 73e, and 74e of the first member 71, the third member 73, and the fourth member 74 may be disposed at positions separated by a predetermined distance L on the upstream side in the ejection direction Jd of the fuel gas 301 with respect to 61b. . As another modification, all of the end surfaces 71e, 72e, 73e, 74e, and 75e of the first to fifth members 71, 72, 73, 74, and 75 are ejected from the opening 61b or the opening 61b of the fuel nozzle 61. It may be arranged at a position separated by a predetermined distance L on the upstream side in the direction Jd.

The operation and effect of the combustion burner 21 of the present embodiment described above will be described.
According to the combustion burner 21 of the present embodiment, the fuel gas 301 is deflected by the inclined surface 71c of the first member 71 inclined toward the adjacent burner side Bs in the horizontal direction Hd orthogonal to the jet direction Jd of the fuel gas 301. Since the fuel gas flow is separated at the end of the inclined surface 71c, the fuel gas recirculation region Rz1 is formed on the downstream side of the first member 71. Similarly, after the fuel gas 301 is deflected by the inclined surface 72c of the second member 72 inclined toward the adjacent burner side Bs in the horizontal direction Hd orthogonal to the ejection direction Jd of the fuel gas 301, the end of the inclined surface 72c is reached. Since the fuel gas flow is separated at the end, a recirculation region Rz2 of the fuel gas 301 is formed on the downstream side of the second member 72. In this way, ignition is promoted and a flame is formed in the recirculation regions Rz1 and Rz2 formed on the downstream side of the first member 71 and the second member 72, whereby internal flame holding is performed.

Further, according to the combustion burner 21 of the present embodiment, the inclined surface 71c and the inclined surface 72c are inclined toward the adjacent burner side Bs with respect to the ejection direction Jd, and the flat surface 71d and the flat surface 72d are in the horizontal direction Hd. Facing the furnace wall side Fs. Since the flat surface 72d of the second member 72 is disposed adjacent to the inclined surface 71c of the first member 71, the fuel guided by the first member 71 as compared with the case where both surfaces are inclined in different directions. Interference between the gas flow and the fuel gas flow guided by the second member 72 is suppressed. Thereby, it is suppressed that the low-flow-rate recirculation area | region Rz1, Rz2 of the downstream of the 1st member 71 and the 2nd member 72 is reduced, and the ignition performance by a flame holder can fully be exhibited.
Thus, according to the combustion burner 21 of the present embodiment, the ignitability can be improved while maintaining the internal flame holding performance.

Further, according to the combustion burner 21 of the present embodiment, the fuel gas is deflected by the third inclined surface 73d of the third member 73 and the fuel gas flow is separated at the end of the inclined surface 73d. A fuel gas recirculation region Rz <b> 3 is formed on the downstream side of the member 73. The ignition is promoted and the flame is formed in the recirculation region Rz3 formed on the downstream side of the third member 73, so that the internal flame holding is promoted in the central portion in the horizontal direction Hd of the combustion burner. Further, the inclined surface 71c of the first member 71 and the inclined surface 72c of the second member 72 are inclined toward the adjacent burner side Bs in the horizontal direction Hd, that is, toward the central portion of the combustion burner 21 in the horizontal direction Hd. The surface 71c and the inclined surface 72c increase the fuel concentration in the central portion, and improve the ignitability in the central portion.

Further, according to the combustion burner 21 of the present embodiment, the third member 73 is disposed in the center portion of the combustion burner 21 in the horizontal direction Hd, and the second member 72 and the fifth member 75 are adjacent to the third member 73. The first member 71 and the fourth member 74 are disposed adjacent to the second member 72 and the fifth member 75. Similar to the first member 71 and the second member 72, the reduction of the low flow rate recirculation regions Rz4, Rz5 on the downstream side of the fourth member 74 and the fifth member 75 is suppressed, and the ignition performance by the flame holder is reduced. Can fully demonstrate. Further, since the inclined surface 74c of the fourth member 74 and the inclined surface 75c of the fifth member 75 are inclined toward the horizontal furnace wall side Fs, that is, toward the horizontal central portion of the combustion burner 21, the inclined surface 74c. In addition, the fuel concentration in the central portion is increased by the inclined surface 75c, and the ignitability in the central portion is improved.

[Second Embodiment]
Next, the combustion burner 21C according to the second embodiment of the present invention will be described. The present embodiment is a modification of the first embodiment, and is the same as the first embodiment except for a case specifically described below.
In the first embodiment, the inclined surface 74c of the fourth member 74 and the inclined surface 75c of the fifth member 75 are surfaces inclined toward the furnace wall side Fs, respectively. In contrast, in the present embodiment, all the inclined surfaces 71c, 72c, 73c, 74c, and 75c included in the first to fifth members 71, 72, 73, 74, and 75 are inclined toward the adjacent burner side Bs. Yes.

FIG. 8 is a longitudinal sectional view of a combustion burner 21C of the second embodiment.
In the combustion burner 21 </ b> C of the present embodiment, the first member 71 and the second member 72 are the same as those in the first embodiment, and thus the description thereof will be omitted.

In the combustion burner 21 of the first embodiment, the third member 73 includes an inclined surface 73d that is inclined toward the furnace wall side Fs. On the other hand, in the combustion burner 21C of the present embodiment, as shown in FIG. 8, the third member 73 has a flat surface 73f on the furnace wall side Fs of the widened portion 73b.

Further, in the combustion burner 21 of the first embodiment, the inclined surface 74c of the fourth member 74 and the inclined surface 75c of the fifth member 75 are surfaces inclined toward the furnace wall side Fs, respectively. On the other hand, in the combustion burner 21C of the present embodiment, as shown in FIG. 8, the inclined surface 74c of the fourth member 74 and the inclined surface 75c of the fifth member 75 are inclined to the adjacent burner side Bs, respectively. It is.

Next, referring to FIG. 9, the recirculation regions Rz1, Rz2, Rz3 formed by the widened portions 71b, 72b, 73b, 74b, 75b of the first to fifth members 71, 72, 73, 74, 75. Rz4 will be described. FIG. 9 is a partially enlarged view of the internal member 64C of the combustion burner 21 shown in FIG. The recirculation regions Rz1, Rz2, Rz3, Rz4, and Rz5 are formed in front of the end surfaces 71e, 72e, 73e, 74e, and 75e (see FIG. 8) of the first to fifth members 71, 72, 73, 74, and 75, respectively. It is an area to be done. The arrows shown in FIG. 9 indicate the flow of the fuel gas 301 separated at the downstream ends of the first to fifth members 71, 72, 73, 74, 75.

As shown in FIG. 9, the inclined surface 71c of the first member 71, the inclined surface 72c of the second member 72, the inclined surface 73c of the third member 73, the inclined surface 74c of the fourth member 74, and the inclined surface of the fifth member 75. 75c is inclined toward the adjacent burner side Bs with respect to the ejection direction Jd. The flat surface 71d of the first member 71, the flat surface 72d of the second member 72, the flat surface 73f of the third member 73, the flat surface 74d of the fourth member 74, and the flat surface 75d of the fifth member 75 are the furnace in the horizontal direction Hd. Facing the wall side Fs.

The flat surface 72d of the second member 72 is disposed adjacent to the inclined surface 71c of the first member 71, the flat surface 73f of the third member 73 is disposed adjacent to the inclined surface 72c of the second member 72, and the third The flat surface 75d of the fifth member 75 is disposed adjacent to the inclined surface 73c of the member 73, and the flat surface 74d of the fourth member 74 is disposed adjacent to the inclined surface 75c of the fifth member 75. Therefore, interference between the recirculation region Rz1 and the recirculation region Rz2, interference between the recirculation region Rz2 and the recirculation region Rz3, interference between the recirculation region Rz3 and the recirculation region Rz5, and the recirculation region Rz5 and the recirculation region Rz4. Interference is suppressed. As a result, the recirculation regions Rz1, Rz2, Rz3, Rz4, and Rz5 are prevented from being reduced, the flame holding performance by the first to fifth members 71, 72, 73, 74, and 75 is stabilized, and the ignition performance is sufficient. Can be demonstrated.

As shown in FIG. 9, among the recirculation regions Rz1, Rz2, Rz3, Rz4, and Rz5, the recirculation region Rz4 that is disposed closest to the burner side Bs is the recirculation region Rz1 that is disposed closest to the furnace wall side Fs. Is smaller than This is because the straight flow of the fuel gas combustion air 302 ejected from the combustion air flow path P2 on the adjacent burner side Bs interferes with the recirculation region Rz4. On the other hand, the straight flow of the fuel gas combustion air 302 ejected from the combustion air flow path P2 on the furnace wall side Fs does not interfere with the recirculation region Rz1.

The fuel gas recirculation region Rz4 adjacent to the combustion air nozzle 62 on the adjacent burner side Bs in the horizontal direction Hd is formed in a direction approaching the flow of the fuel gas combustion air 302 ejected from the combustion air nozzle 62. Then, the flow of the fuel gas combustion air 302 acts and shrinks. On the other hand, the recirculation region Rz1 of the fuel gas 301 adjacent to the combustion air nozzle 62 on the furnace wall side Fs in the horizontal direction Hd is away from the flow of the fuel gas combustion air 302 ejected from the combustion air nozzle 62. Thus, the flow of the fuel gas combustion air 302 does not act and does not shrink. Therefore, the recirculation region Rz4 on the adjacent burner side Bs in the horizontal direction Hd where the heat load due to the flame of the other combustion burner is large is reduced, and the heat on the furnace wall side Fs in the horizontal direction Hd without the heat load due to the flame of the other combustion burner is reduced. The recirculation region Rz1 is enlarged, and the difference in heat load between the adjacent burner side Bs and the furnace wall side Fs in the horizontal direction Hd is reduced, and the internal flame holding is further promoted.

In the combustion burner 21 </ b> C of the present embodiment, there is a flame of another adjacent combustion burner on the adjacent burner side Bs that is the upstream side of the flame swirl flow C, and the flame wall side Fs that is the downstream side of the flame swirl flow C. There is no flame of other adjacent burner. In the combustion burner 21C of the present embodiment, the recirculation region Rz4 on the adjacent burner side Bs where the heat load is high is smaller than the recirculation region Rz1 on the furnace wall side Fs where the heat load is low, so the horizontal direction Hd of the combustion burner 21C The difference in the thermal load at each position of is reduced, and the internal flame holding is promoted.

In the combustion burner 21 </ b> C shown in FIG. 9, the combustion air nozzle 62 has the fuel gas combustion air 302 in the same direction as the jet direction Jd of the fuel gas 301 at the end of the adjacent burner side Bs and the end of the furnace wall side Fs. However, other modes may be used.

For example, like the combustion burner 21D of the modified example of FIG. 10, the combustion air nozzle 62 is adjacent to the ejection direction Jd of the fuel gas 301 at the end of the adjacent burner side Bs and the end of the furnace wall side Fs. The fuel gas combustion air 302 may be ejected in a direction inclined toward the burner side Bs. The flow of the fuel gas combustion air 302 ejected from the combustion air nozzle 62 is away from the recirculation region Rz4 of the fuel gas 301 on the adjacent burner side Bs in the horizontal direction Hd, and the recirculation region Rz4 is prevented from being reduced. Is done. Further, the flow of the fuel gas combustion air 302 ejected from the combustion air nozzle 62 is in a direction along the recirculation region Rz1 of the fuel gas 301 adjacent to the combustion air nozzle 62 on the furnace wall side Fs in the horizontal direction Hd. Appropriate ignition and internal flame holding can be performed.

Also, for example, the combustion air nozzle 62 causes the fuel gas combustion air 302 to flow straight in the same direction as the jet direction Jd of the fuel gas 301 at the end of the combustion wall burner 21D shown in FIG. And the secondary air is ejected in the direction inclined toward the adjacent burner side Bs with respect to the jet direction Jd of the fuel gas 301 at the end of the adjacent burner side Bs. Also good.

[Other Embodiments]
In the embodiment described above, each member of the internal member 64 is configured by the flat portion and the widened portion, but is not limited to this configuration, and may be configured by only the widened portion.
In the above-described embodiment, the fuel nozzle, the combustion air nozzle, and the secondary air nozzle are rectangular, but the shape is not limited to this, and may be circular.

In the above-described embodiment, the boiler according to the present invention is a coal-fired boiler. However, the solid fuel may be a boiler using biomass, petroleum coke, petroleum residue, or the like. Further, the fuel is not limited to a solid fuel, and can be used for an oil-fired boiler such as heavy oil. Furthermore, the present invention can be applied to mixed burning of these fuels.

In the combustion burner according to the present invention, the fuel nozzle, the combustion air nozzle, and the secondary air nozzle do not necessarily have to be arranged in parallel, and the fuel nozzle and the secondary air nozzle gradually move toward the tip of the combustion burner. You may arrange | position a secondary air nozzle diagonally so that it may space apart. In this case, the distance between the fuel nozzle and the secondary air nozzle in the vicinity of the ejection opening of the fuel nozzle only needs to be maintained so as not to disturb the flow of the fuel gas. By arranging the secondary air nozzles obliquely, it is possible to achieve a lower NOx by reducing the amount of air at the outer periphery of the ignition part and suppressing external flame holding in the fuel nozzle.

10 Coal-fired boiler 11 Furnace 11a Furnace wall (heat transfer tube)
DESCRIPTION OF SYMBOLS 12 Combustion apparatus 13 Flue 21,21A, 21B, 21C, 21D, 22,23,24,25 Combustion burner 39 Additional air nozzle 61 Fuel nozzle 61a Inner wall surface 61b, 62b Opening 61c Outer wall surface 62 Combustion air nozzle 63 2 Next air nozzles 64, 64A Internal member 71 First member 72 Second member 73 Third member 74 Fourth member 75 Fifth member 71a, 72a, 73a, 74a, 75a Flat portion 71b, 72b, 73b, 74b, 75b Widened portion (Flame holding part)
71c, 72c, 73c, 73d, 74c, 75c Inclined surfaces 71d, 72d, 74d, 75d Flat surfaces 71e, 72e, 73e, 74e, 75e End surfaces 87, 88 Support member 301 Fuel gas Bs Adjacent burner side (one side)
Fs furnace wall side (the other side)
Hd horizontal direction Jd ejection direction P1 fuel gas flow path P2 combustion air flow path P3 secondary air flow path Rz1, Rz2, Rz3, Rz4, Rz5 recirculation region

Claims (11)

1. A fuel nozzle that ejects fuel gas mixed with fuel and air;
   A combustion air nozzle that ejects air from the outside of the fuel nozzle;
   A plate-like first member disposed in the fuel nozzle along the ejection direction of the fuel gas;
   A plate-like second member disposed in the fuel nozzle along the ejection direction and disposed adjacent to one side of the first member in a predetermined direction intersecting the ejection direction;
   The first member is
   A first inclined surface disposed at a downstream end in the ejection direction;
   A first flat surface disposed at a downstream end in the ejection direction,
   The second member is
   A second inclined surface disposed at a downstream end in the ejection direction;
   A second flat surface disposed at a downstream end in the ejection direction,
   The first inclined surface and the second inclined surface are surfaces that face the one side and are inclined toward the one side with respect to the ejection direction,
   The first and second flat surfaces are combustion burners that are surfaces that face the other side of the predetermined direction and extend along the ejection direction.
2. A plate-like third member disposed along the ejection direction in the fuel nozzle and disposed adjacent to the one side of the second member;
   The third member is
   Disposed in the center of the fuel nozzle in the predetermined direction;
   A third inclined surface disposed at the downstream end in the ejection direction;
   The combustion burner according to claim 1, wherein the third inclined surface is a surface that faces the other side and is inclined toward the other side with respect to the ejection direction.
3. A plate-like fourth member disposed in the fuel nozzle along the ejection direction;
   A plate-like fifth member disposed along the ejection direction in the fuel nozzle and disposed adjacent to the other side of the fourth member;
   The fourth member is
   A fourth inclined surface disposed at the downstream end in the ejection direction;
   A fourth flat surface disposed at the downstream end in the ejection direction,
   The fifth member is
   A fifth inclined surface disposed at the downstream end in the ejection direction;
   A fifth flat surface disposed at the downstream end in the ejection direction,
   The fourth inclined surface and the fifth inclined surface are surfaces that face the other side and are inclined toward the other side with respect to the ejection direction,
   The fourth flat surface and the fifth flat surface are surfaces that face the one side and extend along the ejection direction,
   The third member is
   Disposed adjacent to the other side of the fifth member;
   A sixth inclined surface disposed at the downstream end in the ejection direction;
   The combustion burner according to claim 2, wherein the sixth inclined surface is a surface that faces the one side and is inclined toward the one side with respect to the ejection direction.
4. A plate-like third member disposed along the ejection direction in the fuel nozzle and disposed adjacent to the one side of the second member;
   The third member is
   Disposed in the center of the fuel nozzle in the predetermined direction;
   A third inclined surface disposed at the downstream end in the ejection direction;
   A third flat surface disposed at the downstream end in the ejection direction,
   The third inclined surface is a surface that faces the one side and is inclined toward the one side with respect to the ejection direction,
   The third flat surface is a surface facing the other side and extending along the ejection direction,
   The combustion burner according to claim 1, wherein a flame of another combustion burner is guided from the one side and a furnace wall is arranged on the other side.
5. A plate-like fourth member disposed in the fuel nozzle along the ejection direction;
   A plate-like fifth member disposed along the ejection direction in the fuel nozzle and disposed adjacent to the other side of the fourth member;
   The fourth member is
   A fourth inclined surface disposed at the downstream end in the ejection direction;
   A fourth flat surface disposed at the downstream end in the ejection direction,
   The fifth member is
   A fifth inclined surface disposed at the downstream end in the ejection direction;
   A fifth flat surface disposed at the downstream end in the ejection direction,
   The fourth inclined surface and the fifth inclined surface are surfaces that face the one side and are inclined toward the one side with respect to the ejection direction,
   The fourth flat surface and the fifth flat surface are surfaces that face the other side and extend along the ejection direction,
   The third member is
   Disposed adjacent to the other side of the fifth member;
   A sixth inclined surface disposed at the downstream end in the ejection direction;
   The combustion burner according to claim 4, wherein the sixth inclined surface is a surface that faces the one side and is inclined toward the one side with respect to the ejection direction.
6. The combustion burner according to claim 4 or 5, wherein the combustion air nozzle ejects air in a direction inclined toward the one side with respect to the ejection direction at an end portion on the one side.
7. The combustion burner according to claim 6, wherein the combustion air nozzle ejects air in a direction inclined toward the one side with respect to the ejection direction at an end portion on the other side.
8. The combustion burner according to any one of claims 1 to 7, wherein a position of a downstream end of the first member in the ejection direction is different from a position of a downstream end of the second member in the ejection direction. .
9. The combustion burner according to any one of claims 1 to 7, wherein a position of a downstream end of the first member in the ejection direction and a position of a downstream end of the second member in the ejection direction are the same position. .
10. A furnace that is hollow and installed along the vertical direction;
    The combustion burner according to any one of claims 1 to 9, which is disposed in the furnace,
    A flue disposed at the top of the furnace,
    Boiler with.
11. The boiler according to claim 10, further comprising an additional air supply unit at an upper part of the combustion burner of the furnace.

Images