JP2018132278A - Combustion burner and boiler including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the amount of NOx generated while suppressing the corrosion of a furnace wall due to the generation of hydrogen sulfide and the interference due to the flame of another adjacent combustion burner. SOLUTION: A fuel nozzle 110 forming a fuel gas flow path 111, a secondary air nozzle 120 forming a secondary air flow path 121, and a secondary air nozzle 120 are arranged above and below the secondary air nozzle 120, and are arranged in a furnace 11. A pair of secondary air supply ports for supplying secondary air, and inner flow paths 121A and 121C having secondary air flow paths 121 located on the right and left sides of the fuel gas flow path 111 adjacent to the fuel gas flow path 111. It is divided into outer flow paths 121B and 121D arranged outside the inner flow paths 121A and 121C, and the flow velocity of the secondary air flowing through the inner flow paths 121A and 121C is that of the secondary air flowing through the outer flow paths 121B and 121D. Provided is a combustion burner including a pair of adjusting mechanisms 140A, 140B, which are adjusted to be lower than the flow velocity. [Selection diagram] FIG. 6

Description

  The present invention relates to a combustion burner applied to a boiler for generating steam for power generation or factory use, and a boiler provided with the combustion burner.

  2. Description of the Related Art Conventionally, a solid fuel burning burner including a fuel burner that inputs pulverized coal and primary air into a furnace and a secondary port for a fuel burner that injects secondary air from the outer periphery of the fuel burner is known (for example, a patent) Reference 1). The solid fuel burning burner of Patent Literature 1 includes a pair of secondary air input ports arranged above and below a secondary port for a fuel burner.

In the solid fuel burning burner of Patent Document 1, secondary air is supplied from above and below the fuel burner secondary port. Therefore, the upper and lower sides of the flame formed by the fuel burner are regions where the amount of air relative to the fuel is relatively large.
On the other hand, the solid fuel burning burner of Patent Document 1 does not include secondary air input ports on the left and right of the fuel burner secondary port. Therefore, the right and left sides of the flame formed by the fuel burner are regions where the amount of air relative to the fuel is relatively small.

JP2015-200500A

In the solid fuel-burning burner of Patent Document 1, when the right and left sides of the flame formed by the fuel burner are in a reducing atmosphere region where the amount of air to the fuel is relatively small, corrosion is likely to occur in adjacent furnace walls. There is a problem. This is because the sulfur content (S content) in the pulverized coal is converted to hydrogen sulfide (H ₂ S) and contacts the furnace wall in the reducing atmosphere region.

  Moreover, the boiler provided with the solid fuel burning burner of patent document 1 employ | adopts the swirl combustion system by which a solid fuel burning burner is arrange | positioned at four corner parts. Therefore, there is a possibility that the flame of the solid fuel burning burner on the upstream side in the swirling direction interferes with the flame of the solid fuel burning burner on the downstream side, and the combustion is hindered to deteriorate the combustion characteristics.

  Further, in the solid fuel-fired burner of Patent Document 1, generation of hydrogen sulfide can be suppressed by increasing the flow rate of the secondary air supplied to the fuel burner secondary port. However, when the flow rate of the secondary air introduced from the fuel burner secondary port into the furnace increases with the increase in the flow rate of the secondary air, the flow rate of the mixed flow of pulverized coal and primary air introduced from the fuel burner. And the flow velocity difference between the secondary air and the secondary air increase. As the flow rate difference increases, vortices are generated when the secondary air and the air-fuel mixture come into contact. If ignition or flame holding is performed in the high oxygen region on the outer periphery of the mixed flow, the amount of NOx generated increases. Resulting in.

  The present invention solves the above-described problems, and a combustion burner capable of reducing the amount of NOx generated while suppressing the corrosion of the furnace wall due to the generation of hydrogen sulfide and the interference caused by the flame of another adjacent combustion burner. It aims at providing the equipped boiler.

  In order to achieve the above object, a combustion burner according to the present invention has a fuel gas flow that extends in a cylindrical shape along an axis and supplies a fuel gas obtained by mixing a pulverized carbon-containing solid fuel and primary air to a furnace. A fuel nozzle that forms a path, a secondary air nozzle that extends in a cylindrical shape along the axis and that forms a secondary air flow path for supplying secondary air from the outside of the fuel nozzle to the furnace, and the secondary A pair of secondary air supply ports that are disposed above and below the air nozzle and supply secondary air to the furnace, and the secondary air flow paths located on the right and left sides of the fuel gas flow path, A secondary gas flow is divided into an inner flow channel adjacent to the fuel gas flow channel and an outer flow channel disposed outside the inner flow channel, and the flow rate of secondary air flowing through the inner flow channel flows through the outer flow channel. Adjust to lower than the air flow rate And a pair of adjusting mechanisms.

  According to the combustion burner of the present invention, the secondary air flow channel located on the right side and the left side of the fuel gas flow channel is divided into an inner flow channel adjacent to the fuel gas flow channel and an outer flow channel disposed outside thereof. The flow rate of the secondary air flowing through the inner flow path is adjusted to be lower than the flow rate of the secondary air flowing through the outer flow path. Since the flow rate of the secondary air flowing through the inner flow path is lower than the flow rate of the secondary air flowing through the outer flow path, it flows through the fuel gas flow path as compared with the case where the inner flow path and the outer flow path are not divided. The flow velocity difference between the fuel gas and the secondary air flowing through the secondary air flow path can be reduced. Therefore, a vortex is generated when the fuel gas and the secondary air come into contact with each other, and a problem that the amount of NOx generated increases in the high oxygen region on the outer peripheral side of the fuel gas can be suppressed.

Further, according to the combustion burner of the present invention, the flow rate of the secondary air flowing through the outer flow path is higher than the flow rate of the secondary air flowing through the inner flow path, so that the inner flow path and the outer flow path are not divided. The same amount of secondary air can be supplied to the furnace. Further, by supplying the secondary air to the furnace at a high speed, hydrogen sulfide (H ₂ S) generated in a region adjacent to the right or left furnace wall of the combustion burner can be appropriately reduced. . Thereby, corrosion of the furnace wall due to generation of hydrogen sulfide is suppressed. Moreover, the interference by the flame of the other adjacent combustion burner can be suppressed by supplying the secondary air to the furnace at a high speed.
As described above, according to the present invention, it is possible to provide a combustion burner capable of reducing the NOx generation amount while suppressing the corrosion of the furnace wall due to the generation of hydrogen sulfide and the interference caused by the flame of another adjacent combustion burner.

  In the combustion burner according to the present invention, the adjustment mechanism is disposed on a distal end side of the secondary air flow path located on the right side and the left side of the fuel gas flow path so as to extend along the axis. A pair of partition walls that divide an air flow path into the inner flow path and the outer flow path; a pair of adjustment portions that are disposed on the base end side of the secondary air flow path and connected to the pair of partition walls; And the partition is arranged such that an opening area of the inner flow path to the furnace is larger than an opening area of the outer flow path to the furnace, and the adjustment portion is connected to the inner flow path. It is good also as a structure adjusted so that the flow volume of the inflowing secondary air may become smaller than the flow volume of the secondary air inflowing into the said outer side flow path.

  According to the combustion burner of this configuration, while the flow rate of the secondary air flowing into the inner flow path is adjusted to be smaller than the flow rate of the secondary air flowing into the outer flow path, The partition wall is arranged so that the opening area of the outer channel is larger than the opening area of the outer flow path to the furnace. Therefore, the secondary air that has flowed into the inner channel at a lower flow rate than the outer channel is supplied to the furnace at a lower speed than the secondary air that flows through the outer channel. Moreover, according to the combustion burner of this structure, since a partition is arrange | positioned at the front end side of a secondary air flow path so that it may extend along an axis, a fuel gas and secondary air are furnaces along the same axis. Supplied to. Therefore, a vortex is generated when the fuel gas and the secondary air come into contact with each other, and the problem that the amount of NOx generated increases in the high oxygen region on the outer peripheral side of the fuel gas can be more reliably suppressed.

In the combustion burner configured as described above, the adjustment unit gradually increases the cross-sectional area of the inner flow path from the upstream side to the downstream side of the secondary air flow path, and the flow path breakage of the outer flow path. It may be a plate-like member arranged so as to gradually reduce the area.
By doing in this way, it suppresses that the turbulence arises in the secondary air which flows into an inner side channel and an outer side channel, and suppresses the malfunction which a vortex generate | occur | produces when fuel gas and secondary air contact. Can do.

In the combustion burner configured as described above, the adjustment portion may be a plate-like member formed so as to block a part of the inflow portion into the inner flow path.
By doing in this way, the flow rate of the secondary air which distribute | circulates an inner flow path distribute | circulates an outer flow path by the comparatively simple structure of closing a part of inflow part to an inner flow path with a plate-shaped member. It can adjust so that it may become lower than the flow velocity of secondary air.

  In the combustion burner according to the present invention, the adjustment mechanism is a pair of partition walls disposed on the front end side of the secondary air flow channel located on the right and left sides of the fuel gas flow channel so as to extend along the axis. The partition wall has an opening area of the inner flow path to the furnace larger than an opening area of the outer flow path to the furnace, and a flow rate of secondary air flowing into the inner flow path is It is good also as a structure arrange | positioned so that it may become smaller than the flow volume of the secondary air which flows in into the said outer side flow path.

  According to the combustion burner of this configuration, while the flow rate of the secondary air flowing into the inner flow path is adjusted to be smaller than the flow rate of the secondary air flowing into the outer flow path, The partition wall is arranged so that the opening area of the outer channel is larger than the opening area of the outer flow path to the furnace. Therefore, the secondary air that has flowed into the inner channel at a lower flow rate than the outer channel is supplied to the furnace at a lower speed than the secondary air that flows through the outer channel. Therefore, a vortex is generated when the fuel gas and the secondary air come into contact with each other, and the problem that the amount of NOx generated increases in the high oxygen region on the outer peripheral side of the fuel gas can be more reliably suppressed.

The combustion burner of the present invention may include a speed reduction mechanism that reduces the flow rate of the secondary air that flows through the secondary air flow channel positioned above and below the fuel gas flow channel.
By providing the speed reduction mechanism, secondary air that is not guided to the right and left secondary air flow paths due to the presence of the pair of adjustment mechanisms is positioned above and below the fuel gas flow path. It is possible to suppress a problem that the flow rate of the secondary air is excessively increased due to being intensively introduced into the secondary air flow path.

A boiler according to the present invention includes a furnace that is installed along a vertical direction and is formed by four wall surfaces, and any one of the above-described combustion burners that is installed for each of the four wall surfaces of the furnace. And the combustion burner blows the fuel gas at an angle with respect to the center of the furnace to form a swirling flow that swirls around the center of the furnace.
According to the boiler of the present invention, in each of the combustion burners installed on each of the four wall surfaces of the furnace so as to form a swirling flow, the secondary air located on the right and left sides of the fuel gas flow path. The flow path is divided into an inner flow path adjacent to the fuel gas flow path and an outer flow path disposed outside thereof, and the flow rate of the secondary air flowing through the inner flow path is the flow rate of the secondary air flowing through the outer flow path. Is adjusted to be lower. Since the flow rate of the secondary air flowing through the inner flow path is lower than the flow rate of the secondary air flowing through the outer flow path, it flows through the fuel gas flow path as compared with the case where the inner flow path and the outer flow path are not divided. The flow velocity difference between the fuel gas and the secondary air flowing through the secondary air flow path can be reduced. Therefore, a vortex is generated when the fuel gas and the secondary air come into contact with each other, and a problem that the amount of NOx generated increases in the high oxygen region on the outer peripheral side of the fuel gas can be suppressed.

  According to the present invention, it is possible to provide a combustion burner capable of reducing the amount of NOx generated while suppressing the corrosion of the furnace wall due to the generation of hydrogen sulfide and the interference caused by the flame of another adjacent combustion burner, and a boiler including the combustion burner. it can.

It is a schematic block diagram showing the pulverized coal burning boiler to which the combustion burner of a 1st embodiment of the present invention was applied. It is a top view showing the combustion burner in the pulverized coal burning boiler shown in FIG. It is a fragmentary longitudinal cross-sectional view of the combustion burner shown in FIG. It is the front view which looked at the combustion burner shown in FIG. 2 from the furnace. It is a front view which shows the flow path width of the opening part of the secondary air flow path of the combustion burner shown in FIG. It is II-II arrow sectional drawing of the combustion burner shown in FIG. It is sectional drawing which shows the modification of a combustion burner. It is sectional drawing which shows the modification of a combustion burner. It is a partial longitudinal cross-sectional view of the combustion burner of 2nd Embodiment. It is a fragmentary longitudinal cross-sectional view of the combustion burner which concerns on the modification of 2nd Embodiment.

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

<First Embodiment>
The pulverized coal fired boiler to which the combustion burner of the first embodiment of the present invention is applied uses pulverized coal obtained by pulverizing coal as a carbon-containing solid fuel, the pulverized coal is burned by the combustion burner, and the heat generated by this combustion is generated. It is a boiler that can be recovered.

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

  The combustion device 12 has a plurality of combustion burners 100A, 100B, 100C, 100D, and 100E mounted on the furnace wall. In this embodiment, the combustion burners 100A, 100B, 100C, 100D, and 100E are arranged as a set having four equal intervals along the circumferential direction with the vertical direction in which the furnace 11 extends as the central axis. 5 sets (5 stages) are arranged along the vertical direction. In addition, although it was set as 5 sets here, it can be set to 6 sets or other arbitrary sets.

  Each combustion burner 100A, 100B, 100C, 100D, 100E is supplied to a pulverized coal machine (mill; pulverizer) 31, 32, 33, 34, 35 via a pulverized coal supply pipe 26, 27, 28, 29, 30. It is connected to. 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. Accordingly, when coal is introduced between a plurality of crushing rollers and a crushing table, pulverized coal that has been crushed to a predetermined size and classified by air for transportation (primary air) is supplied to the pulverized coal supply pipe 26, 27, 28, 29, 30 are supplied to the combustion burners 100A, 100B, 100C, 100D, 100E.

  Further, the furnace 11 is provided with a wind box 36 at a mounting position of each combustion burner 100A, 100B, 100C, 100D, 100E, and one end portion of an air duct (secondary air supply pipe) 37 is provided in the wind box 36. The air duct 37 is connected to a blower 38 at the other end. Furthermore, the furnace 11 is provided with an additional air nozzle 39 vertically above the mounting position of each combustion burner 100A, 100B, 100C, 100D, 100E. The additional air nozzle 39 is connected to an end of a branched air duct 40 branched from the air duct 37. 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 100A, 100B, 100C, 100D, and 100E. In addition, combustion air (additional air) sent by the blower 38 can be supplied from the branch air duct 40 to the additional air nozzle 39.

  Therefore, in the combustion apparatus 12, each combustion burner 100 </ b> A, 100 </ b> B, 100 </ b> C, 100 </ b> D, 100 </ b> E has a pulverized fuel mixture (fuel gas) obtained by mixing pulverized coal and carrier air (primary air) in the furnace 11. In addition to being able to blow, combustion air can be blown into the furnace 11. The combustion device 12 can form a flame by igniting the pulverized fuel mixture with an ignition torch (not shown).

  In the furnace 11, a flue 13 is connected to an upper part in the vertical direction, and a superheater (super heater) 41, which is a heat exchanger for recovering heat of combustion gas as a convection heat transfer section, is connected to the flue 13. 42, reheaters 43 and 44, and economizers 45, 46, and 47 are provided, and heat exchange is performed between the combustion gas generated by the combustion in the furnace 11 and water or steam.

  The flue 13 is connected to an exhaust gas pipe 48 through which the combustion gas subjected to heat exchange is discharged as exhaust gas on the downstream side of the gas flow. This exhaust gas pipe 48 is provided with an air heater 49 between the air duct 37 and performs heat exchange between the air flowing through the air duct 37 and the exhaust gas flowing through the exhaust gas pipe 48, and the combustion burners 100A, 100B, 100C, The temperature of combustion air supplied to 100D and 100E can be raised. Although not shown, the exhaust gas pipe 48 is provided with a denitration device, an electrostatic precipitator, an induction blower, and a desulfurization device, and a chimney is provided at the downstream end.

  Therefore, when the pulverized coal machines 31, 32, 33, 34, and 35 are driven, the generated pulverized coal together with the air for conveyance (primary air), the pulverized coal supply pipes (fuel supply pipes) 26, 27, 28, 29, 30 is supplied to the combustion burners 100A, 100B, 100C, 100D, and 100E. Also, heated combustion air (secondary air) is supplied from the air duct 37 to the combustion burners 100A, 100B, 100C, 100D, and 100E through the wind box 36, and an additional air nozzle is supplied from the branch air duct 40. 39. The temperature of the carrier air (primary air) is low so that the pulverized coal does not ignite, and the combustion air (secondary air) is heated by the air heater 49, so the temperature is higher than the primary air and the pulverized fuel mixture. .

  Then, the combustion burners 100A, 100B, 100C, 100D, and 100E blow the pulverized fuel mixture (fuel gas), which is a mixture of pulverized coal and carrier air, into the furnace 11 and the combustion air into the furnace 11. By igniting, a flame can be formed. Further, the additional air nozzle 39 can perform combustion control for blowing additional air into the furnace 11 and optimizing the amount of air with respect to the pulverized coal. In the furnace 11, the pulverized fuel mixture and the combustion air are burned to generate a flame. When a flame is generated in a region in the lower vertical direction in the furnace 11, the combustion gas (exhaust gas) rises in the furnace 11. And discharged to the flue 13.

  That is, the combustion burners 100A, 100B, 100C, 100D, and 100E blow the pulverized coal mixture and the combustion air (secondary air) into the combustion region in the furnace 11, and ignite at this time, so that the flame swirls in the combustion region. Is formed. This flame swirl rises while swirling and reaches the reduction region. The additional air nozzle 39 blows additional air vertically above the reduction region in the furnace 11. In the furnace 11, the interior is maintained in a reducing atmosphere by setting the air supply amount to be less than the theoretical air amount with respect to the pulverized coal supply amount. The NOx generated by the combustion of the pulverized coal is reduced in the furnace 11, and then additional air (additional air) is supplied to complete the oxidation combustion of the pulverized coal, and the amount of NOx generated by the combustion of the pulverized coal is reduced. Reduced.

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

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

  Here, although the combustion apparatus 12 is demonstrated in detail, since each combustion burner 100A, 100B, 100C, 100D, 100E which comprises this combustion apparatus 12 has comprised the substantially the same structure, it is located in the uppermost stage. Only the combustion burner 100A will be described.

  As shown in FIG. 2, the combustion burner 100 </ b> A is composed of combustion burners 100 </ b> Aa, 100 </ b> Ab, 100 </ b> Ac, 100 </ b> Ad provided on four wall surfaces forming the furnace 11. Each combustion burner 100Aa, 100Ab, 100Ac, 100Ad 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 100Aa, 100Ab, 100Ac, 100Ad on each wall surface of the furnace 11 has a pulverized fuel mixture in which pulverized coal and transport air (primary air) are mixed with the furnace 11 in the center of the furnace 11. In contrast, the air is blown with a slight deviation angle, and combustion air (secondary air) is blown to the outside of the pulverized fuel mixture. Then, by igniting the pulverized fuel mixture from each combustion burner 100Aa, 100Ab, 100Ac, 100Ad, four flames F1, F2, F3, F4 can be formed, and this flame F1, F2, F3, F4 Is a flame swirl flow swirling counterclockwise as viewed from above the furnace 11 (in FIG. 2). In this example, the combustion burners 100Aa, 100Ab, 100Ac, and 100Ad may be arranged so as to form a flame swirl flow that rotates clockwise.

Next, the combustion burner 100A will be described in detail.
As shown in the partial vertical sectional view of FIG. 3 and the front view of FIG. 4, the combustion burner 100A of this embodiment includes a fuel nozzle 110, a secondary air nozzle 120, a pair of secondary air supply ports 130A and 130B. And a pair of adjustment mechanisms 140A and 140B. 3 is a cross-sectional view taken along the arrow II of the combustion burner 100A shown in FIG.

  The fuel nozzle 110 is a member formed to extend in a cylindrical shape along the axis X1. The fuel nozzle 110 forms therein a fuel gas passage 111 for supplying the pulverized fuel mixture supplied from the pulverized coal supply pipe 26 to the furnace 11. The fuel gas channel 111 is a channel whose cross section perpendicular to the axis X1 is rectangular.

  The shape of the opening portion where the fuel nozzle 110 faces the furnace 11 is a shape extending straight in the same direction as the gas flow direction of the pulverized fuel mixture. As shown in FIG. 3, the height of the fuel nozzle 110 in the vertical direction is constant at H1. This is to prevent the pulverized coal contained in the pulverized fuel mixture from being guided to the outer peripheral side with respect to the central axis (axis line X1) of the fuel gas passage 111.

  The secondary air nozzle 120 is a member that is formed so as to extend in a cylindrical shape along the axis X <b> 1 and is disposed so as to surround the outside with respect to the axis X <b> 1 of the fuel nozzle 110. The secondary air nozzle 120 forms an annular secondary air flow path 121 that supplies secondary air to the furnace 11 between its inner peripheral surface and the outer peripheral surface of the fuel nozzle 110. The secondary air channel 121 is a channel having a rectangular cross section perpendicular to the axis X1.

  The secondary air nozzle 120 supplies the secondary air supplied from the wind box 36 to the furnace 11 via the secondary air flow path 121. The height of the secondary air nozzle 120 in the vertical direction is a shape in which the base end side is constant at H2 and decreases from H2 to H3 on the distal end side.

  The secondary air supply port 130 </ b> A is disposed above the secondary air nozzle 120 in the vertical direction, and supplies secondary air to the furnace 11. The secondary air supply port 130 </ b> B is disposed below the secondary air nozzle 120 in the vertical direction, and supplies secondary air to the furnace 11. The secondary air supply ports 130 </ b> A and 130 </ b> B supply the secondary air supplied from the wind box 36 to the furnace 11. The heights of the secondary air supply ports 130A and 130B are constant at H4 on the base end side and are lowered from H4 to H5 on the front end side.

Next, the flow path width of the opening of the secondary air flow path 121 to the furnace 11 will be described. FIG. 5 is a front view showing the channel width of the opening to the furnace 11 of the secondary air channel 121 of the combustion burner 100A shown in FIG.
Here, W1 is the horizontal width of the opening of the fuel nozzle 110, and W2 is the horizontal width of the opening of the secondary air nozzle 120.

  Here, the flow width of the opening to the furnace 11 of the secondary air flow path 121 located on the right side of the fuel gas flow path 111 is Wr, and the secondary air flow located on the left side of the fuel gas flow path 111 The flow path width of the opening part to the furnace 11 of the path 121 is set to Wl. Further, the channel width of the opening to the furnace 11 of the secondary air channel 121 positioned above the fuel gas channel 111 is Hu, and the secondary air channel 121 positioned below the fuel gas channel 111 is Let Hd be the flow path width of the opening to the furnace 11.

In the present embodiment, the fuel gas flow path 111 and the secondary air flow path 121 are formed so that the following conditional expression (1) is satisfied among Wr, Wl, Hu, and Hd.
Hu + Hd <Wr + Wl (1)
This condition is that the total flow path width of the opening to the furnace 11 of the secondary air flow path 121 located on the right and left sides of the fuel gas flow path 111 is located above and below the fuel gas flow path 111. This is a condition that the secondary air flow passage 121 is larger than the total flow passage width of the opening to the furnace 11. By satisfying the conditional expression (1), the flow rate of the secondary air supplied to the furnace from the right and left sides of the fuel gas passage 111 where the secondary air supply ports 130A and 130B are not arranged increases.

  Here, the fuel gas channel 111 and the secondary air channel 121 may be formed so that Wr and Wl have the same channel width. The passage width Wr of the opening of the secondary air passage 121 located on the right side of the fuel gas passage 111 and the passage width of the opening of the secondary air passage 121 located on the left side of the fuel gas passage 111 By matching Wl, it is possible to appropriately suppress the corrosion of the furnace wall due to the generation of hydrogen sulfide in the region adjacent to the furnace wall and the interference due to the flame of another adjacent combustion burner.

  Further, the fuel gas passage 111 and the secondary air passage 121 may be formed so that Wr and Wl have different passage widths. As shown in FIG. 2, in the combustion burner 100 </ b> A of this embodiment, when the combustion burner 100 </ b> A is viewed from the furnace 11, the furnace wall is disposed on the left side of the fuel gas flow path 111, and from the right side of the fuel gas flow path 111. Interference is caused by the flame of another combustion burner 100A upstream of the swirl flow.

  Therefore, when the influence of the corrosion of the furnace wall due to the generation of hydrogen sulfide is larger than the interference of the flame, it is desirable to make W1 wider than Wr. By increasing the secondary air supplied from the secondary air flow path 121 located on the left side of the fuel gas flow path 111, corrosion of the furnace wall due to the generation of hydrogen sulfide can be suppressed.

  If the influence of flame interference is greater than the corrosion of the furnace wall due to the generation of hydrogen sulfide, it is desirable to make Wr wider than Wl. By increasing the secondary air supplied from the secondary air flow path 121 located to the right of the fuel gas flow path 111, it is possible to suppress interference due to the flame of the other combustion burner 100A upstream of the swirl flow. it can.

In the present embodiment, it is desirable to form the fuel gas passage 111 and the secondary air passage 121 so that the following conditional expression (2) is satisfied.
1.5 ≦ (Wr + Wl) / (Hu + Hd) ≦ 6 (2)
This condition is that the passage width of the opening to the furnace 11 of the secondary air passage 121 located on the right and left of the fuel gas passage 111 is located above and below the fuel gas passage 111. The condition is that the flow path width of the opening of the secondary air flow path 121 to the furnace 11 is not less than 1.5 times and not more than 6 times. By satisfying the conditional expression (2), the channel width of the opening of the secondary air channel 121 located on the right and left sides of the fuel gas channel 111 is set above and below the fuel gas channel 111. It can be made sufficiently larger than the flow path width of the opening of the secondary air flow path 121 located at the position.

  Next, adjustment mechanisms 140A and 140B for reducing the flow velocity difference between the secondary air flowing through the secondary air flow path 121 and the pulverized fuel mixture flowing through the fuel gas flow path 111 will be described.

  As shown in FIG. 6, the combustion burner 100 </ b> A according to the present embodiment includes a secondary air passage 121 located on the right side of the fuel gas passage 111 and an inner passage 121 </ b> A and an inner passage adjacent to the fuel gas passage 111. 140 A of adjustment mechanisms divided | segmented into the outer side flow path 121B arrange | positioned on the outer side of 121A are provided. Further, in the combustion burner 100A of the present embodiment, the secondary air passage 121 located on the left side of the fuel gas passage 111 is disposed outside the inner passage 121C and the inner passage 121C adjacent to the fuel gas passage 111. An adjustment mechanism 140B that divides the outer flow path 121D is provided.

140 A of adjustment mechanisms are mechanisms which adjust so that the flow velocity of the secondary air which distribute | circulates the inner flow path 121A becomes lower than the flow velocity of the secondary air which distribute | circulates the outer flow path 121B. Similarly, the adjustment mechanism 140B is a mechanism that adjusts the flow velocity of the secondary air flowing through the inner flow path 121C to be lower than the flow velocity of the secondary air flowing through the outer flow path 121D.
As shown in FIG. 6, the adjustment mechanism 140A is a mechanism having a partition wall 140Aa and a partition wall (adjustment unit) 140Ab. The adjustment mechanism 140B is a mechanism having a partition wall 140Ba and a partition wall (adjustment unit) 140Bb.

  The partition wall 140 </ b> Aa is disposed on the front end side (furnace 11 side) of the secondary air flow path 121 located on the right side of the fuel gas flow path 111 so as to extend along the axis X <b> 1 and flows through the secondary air flow path 121. It is a plate-like member that is divided into a channel 121A and an outer channel 121B. In addition, the partition wall 140Ba is disposed on the distal end side (furnace 11 side) of the secondary air flow path 121 located on the left side of the fuel gas flow path 111 so as to extend along the axis line X1. It is a plate-like member that is divided into an inner channel 121C and an outer channel 121D. As shown in FIG. 4, the partition walls 140 </ b> Aa and 140 </ b> Ba are formed so as to extend along the vertical direction from the lower end to the upper end of the fuel gas channel 111.

  The partition wall 140Ab is a plate-like member that is disposed on the proximal end side of the secondary air flow path 121 and connected to the partition wall 140Aa. The partition wall 140Bb is a plate-like member that is disposed on the proximal end side of the secondary air flow path 121 and connected to the partition wall 140Ba. The partition walls 140Ab and 140Bb are formed so as to extend along the vertical direction from the lower end to the upper end of the fuel gas flow path 111.

As shown in FIG. 6, the partition wall 140Aa is arranged such that the opening area of the inner flow path 121A to the furnace 11 is larger than the opening area of the outer flow path 121B to the furnace 11. Further, the partition wall 140Ba is arranged so that the opening area of the inner flow path 121C to the furnace 11 is larger than the opening area of the outer flow path 121D to the furnace 11.
Further, the partition wall 140Ab is disposed so that the flow rate of the secondary air flowing into the inner flow path 121A is smaller than the flow rate of the secondary air flowing into the outer flow path 121B. Further, the partition wall 140Bb is disposed so that the flow rate of the secondary air flowing into the inner flow path 121C is smaller than the flow rate of the secondary air flowing into the outer flow path 121D.

  The partition wall 140Ab is arranged so as to gradually increase the channel cross-sectional area of the inner channel 121A and gradually decrease the channel cross-sectional area of the outer channel 121B from the upstream side to the downstream side of the secondary air channel 121. Has been. Further, the partition wall 140Bb gradually increases the cross-sectional area of the inner flow path 121C from the upstream side to the downstream side of the secondary air flow path 121, and gradually decreases the cross-sectional area of the outer flow path 121D. Is arranged.

  The operation and effect of the combustion burner 100A of the present embodiment described above will be described.

  According to the combustion burner 100 </ b> A of the present embodiment, the secondary air flow path 121 located on the right and left sides of the fuel gas flow path 111 is disposed on the inner flow paths 121 </ b> A and 121 </ b> C adjacent to the fuel gas flow path 111 and on the outside thereof. Divided into the outer flow paths 121B and 121D to be arranged, the flow rate of the secondary air flowing through the inner flow paths 121A and 121C is adjusted to be lower than the flow rate of the secondary air flowing through the outer flow paths 121B and 121D. The Since the flow rate of the secondary air flowing through the inner flow paths 121A and 121C is lower than the flow rate of the secondary air flowing through the outer flow paths 121B and 121D, the inner flow paths 121A and 121C and the outer flow paths 121B and 121D are not divided. Compared to the case, the flow velocity difference between the fuel gas flowing through the fuel gas flow path 111 and the secondary air flowing through the secondary air flow path 121 can be reduced. Therefore, a vortex is generated when the fuel gas and the secondary air come into contact with each other, and a problem that the amount of NOx generated increases in the high oxygen region on the outer peripheral side of the fuel gas can be suppressed.

Further, according to the combustion burner 100A of the present embodiment, the flow rate of the secondary air that flows through the outer flow paths 121B and 121D is higher than the flow rate of the secondary air that flows through the inner flow paths 121A and 121C. The same amount of secondary air can be supplied to the furnace 11 as when 121A, 121C and the outer flow paths 121B, 121D are not divided. Further, by supplying secondary air to the furnace 11 at a high speed, hydrogen sulfide (H ₂ S) generated in a region adjacent to the right or left furnace wall of the combustion burner 100A is appropriately reduced. Can do. Thereby, corrosion of the furnace wall due to generation of hydrogen sulfide is suppressed. Moreover, the interference by the flame of the other adjacent combustion burner can be suppressed by supplying secondary air to the furnace 11 at a high speed.
Thus, according to the present embodiment, it is possible to provide the combustion burner 100A capable of reducing the NOx generation amount while suppressing the corrosion of the furnace wall due to the generation of hydrogen sulfide and the interference caused by the flame of another adjacent combustion burner. it can.

  Further, in the combustion burner 100A of the present embodiment, the adjustment mechanisms 140A and 140B are provided on the front end side of the secondary air flow path 121 located on the right and left sides of the fuel gas flow path 111 so as to extend along the axis X1. A pair of partition walls 140Aa and 140Ba, and a pair of partition walls (adjusting portions) 140Ab and 140Bb which are disposed on the proximal end side of the secondary air flow path 121 and connected to the pair of partition walls 140Aa and 140Ba. . Here, the partition walls 140Aa and 140Ba are arranged such that the opening areas of the inner flow paths 121A and 121C to the furnace 11 are larger than the opening areas of the outer flow paths 121B and 121D to the furnace 11. Further, the partition walls (adjusting units) 140Ab and 140Bb are adjusted so that the flow rate of the secondary air flowing into the inner flow paths 121A and 121C is smaller than the flow rate of the secondary air flowing into the outer flow paths 121B and 121D. Yes.

  According to the combustion burner 100A of the present embodiment, the flow rate of the secondary air flowing into the inner flow paths 121A and 121C is adjusted to be smaller than the flow rate of the secondary air flowing into the outer flow paths 121B and 121D. Thus, the partition walls 140Aa and 140Ba are arranged so that the opening areas of the inner flow paths 121A and 121C to the furnace 11 are larger than the opening areas of the outer flow paths 121B and 121D to the furnace 11.

  Therefore, the secondary air that has flowed into the inner flow paths 121A and 121C at a lower flow rate than the outer flow paths 121B and 121D is supplied to the furnace 11 at a lower speed than the secondary air that flows through the outer flow paths 121B and 121D. . Further, according to the combustion burner 100A of the present embodiment, the partition walls 140Aa and 140Ba are arranged on the front end side of the secondary air flow path 121 so as to extend along the axis X1, so that the pulverized fuel mixture and the secondary air Air is supplied to the furnace 11 along the same axis X1. Therefore, a vortex is generated when the pulverized fuel mixture and the secondary air come into contact with each other, and the problem that the amount of NOx generated increases in the high oxygen region on the outer peripheral side of the pulverized fuel mixture can be more reliably suppressed. .

In the combustion burner 100A of the present embodiment, the partition walls (adjusting parts) 140Ab and 140Bb gradually increase the flow passage cross-sectional areas of the inner flow passages 121A and 121C from the upstream side to the downstream side of the secondary air flow passage 121, And it is a plate-shaped member arrange | positioned so that the flow-path cross-sectional area of the outer side flow paths 121B and 121D may reduce gradually.
In this way, turbulence is prevented from occurring in the secondary air flowing into the inner flow paths 121A, 121C and the outer flow paths 121B, 121D, and vortices are generated when the pulverized fuel mixture and the secondary air come into contact with each other. The malfunction which generate | occur | produces can be suppressed.

The adjustment mechanisms 140A and 140B of the present embodiment are arranged so that the flow rate of the secondary air flowing into the inner flow paths 121A and 121C is smaller than the flow rate of the secondary air flowing into the outer flow paths 121B and 121D. Although it has 140Ab and 140Bb, other modes may be used.
For example, as shown in FIG. 7, it is good also as a modification which replaces with partition 140Ab and 140Bb, and provides partition 140Ac and 140Bc.

FIG. 7 is a cross-sectional view showing a modification of the combustion burner 100A, and is a cross-sectional view taken along the line II-II of the combustion burner shown in FIG.
The partition walls 140Ac and 140Bc of the present modification are plate-like members formed so as to extend along the vertical direction from the lower end to the upper end of the fuel gas channel 111 along the vertical direction. In the partition walls 140Ac and 140Bc, slits are formed that extend along the vertical direction from the lower end to the upper end of the fuel gas flow path 111 along the vertical direction. The secondary air flowing through the secondary air flow path 121 flows into the inner flow paths 121A and 121C through the slits.

Thus, the partition walls 140Ac and 140Bc are members formed so as to block a part of the inflow portion where the secondary air flows into the inner flow paths 121A and 121C. The position where the slit is formed is not limited to the position between the partition walls 140Aa and 140Ba and the outer peripheral surface of the fuel nozzle 110 as shown in FIG. For example, a slit may be provided on the partition walls 140 </ b> Aa and 140 </ b> Ba, or a slit may be provided on the outer peripheral surface side of the fuel nozzle 110.
Further, for example, instead of the slits, the partition walls 140Ac and 140Bc may be punched metal in which an opening hole that opens in the secondary air flow direction is formed on the entire surface.

Moreover, you may employ | adopt the partition 140Ad and 140Bd shown in FIG. 8 as adjustment mechanism 140A, 140B of this embodiment. 8 is a cross-sectional view showing a modification of the combustion burner 100A, and is a cross-sectional view taken along the line II-II of the combustion burner shown in FIG.
In the partition walls 140Ad and 140Bd shown in FIG. 8, the opening area of the inner flow paths 121A and 121C to the furnace 11 is larger than the opening area of the outer flow paths 121B and 121D to the furnace 11, and the inner flow paths 121A and 121C The plate-like member is arranged so that the flow rate of the secondary air flowing in becomes smaller than the flow rate of the secondary air flowing into the outer flow paths 121B and 121D.

  According to the combustion burner shown in FIG. 8, while the flow rate of the secondary air flowing into the inner flow paths 121A and 121C is adjusted to be smaller than the flow rate of the secondary air flowing into the outer flow paths 121B and 121D. The partition walls 140Ad and 140Bd are arranged such that the opening areas of the inner flow paths 121A and 121C to the furnace 11 are larger than the opening areas of the outer flow paths 121B and 121D to the furnace 11. Therefore, the secondary air that has flowed into the inner flow paths 121A and 121C at a lower flow rate than the outer flow paths 121B and 121D is supplied to the furnace 11 at a lower speed than the secondary air that flows through the outer flow paths 121B and 121D. . Therefore, a vortex is generated when the pulverized fuel mixture and the secondary air come into contact with each other, and the problem that the amount of NOx generated increases in the high oxygen region on the outer peripheral side of the pulverized fuel mixture can be more reliably suppressed. .

Second Embodiment
Next, a second embodiment of the present invention will be described.
The second embodiment is a modification of the first embodiment, and is the same as the first embodiment except for the case described below, and the description below is omitted.
The combustion burner of the present embodiment is different from the combustion burner 100A of the first embodiment in that a speed reduction mechanism is further provided.

  As shown in FIG. 9, the secondary air nozzle 120 of the present embodiment has a throttle 150 that locally reduces the cross-sectional area of the secondary air flow passage 121 in the vicinity of the tip portion facing the furnace 11. I have. The throttle 150 is a speed reduction mechanism that reduces the flow velocity of the secondary air that flows through the secondary air passage 121 located above and below the fuel gas passage 111.

  By providing the throttle unit 150 (deceleration mechanism), the pressure loss when the secondary air passes through the secondary air passage 121 positioned above and below the fuel gas passage 111 increases. As a result, the secondary air that is not guided to the right and left secondary air flow paths 121 of the fuel gas flow path 111 due to the presence of the pair of adjustment mechanisms 140A and 140B flows above and below the fuel gas flow path 111. It is possible to suppress a problem that the flow rate of the secondary air is excessively increased due to being intensively introduced into the located secondary air flow path 121.

A plate-like member may be provided in place of the throttle unit 150 as a speed reduction mechanism for reducing the flow rate of the secondary air flowing through the secondary air flow path 121 located above and below the fuel gas flow path 111.
For example, as shown in FIG. 10, a plate-like member (deceleration mechanism) 160 extending from the right end to the left end of the secondary air flow path 121 may be provided at a position where the throttle unit 150 is provided in FIG. By providing the plate-like member 160 that partially retains the flow of the secondary air flowing through the secondary air flow path 121, the flow rate of the secondary air flowing through the secondary air flow path 121 can be reduced.

  The position where the plate-like member is arranged is not limited to the position where the diaphragm 150 is provided in FIG. For example, as indicated by a broken line in FIG. 10, a plate-like member 170 extending from the right end to the left end of the secondary air flow path 121 may be disposed upstream of the position where the throttle portion 150 is provided in FIG. 9. .

<Other embodiments>
In the combustion burner 100 </ b> A described above, a flame holder may be disposed inside the tip of the fuel nozzle 110 facing the furnace 11. The flame holder is formed by, for example, one or a plurality of plate-like members extending along the vertical direction. By arranging the flame holder, the ignition performance and flame holding performance of the pulverized fuel mixture can be enhanced.

DESCRIPTION OF SYMBOLS 10 Pulverized coal fired boiler 11 Furnace 12 Combustion device 26, 27, 28, 29, 30 Pulverized coal supply pipe (fuel supply pipe)
31, 32, 33, 34, 35 Pulverized coal machine (pulverizer)
36 Wind box 37 Air duct (secondary air supply pipe)
38 Blower 49 Air heater (heat exchanger)
100A, 100B, 100C, 100D, 100E Combustion burner 110 Fuel nozzle 111 Fuel gas channel 120 Secondary air nozzle 121 Secondary air channel 121A, 121C Inner channel 121B, 121D Outer channel 130A, 130B Secondary air supply port 140A, 140B Adjustment mechanism 140Aa, 140Ba Partition 140Ab, 140Bb Partition (Adjustment part)
140Ac, 140Bc Partition 140Ad, 140Bd Partition 150 Restriction (deceleration mechanism)
160,170 Plate member (deceleration mechanism)

Claims (7)

A fuel nozzle that forms a fuel gas passage that extends in a cylindrical shape along an axis and supplies a fuel gas obtained by mixing a fuel obtained by pulverizing a carbon-containing solid fuel and primary air to a furnace;
A secondary air nozzle extending in a cylindrical shape along the axis and forming a secondary air flow path for supplying secondary air from the outside of the fuel nozzle to the furnace;
A pair of secondary air supply ports disposed above and below the secondary air nozzle for supplying secondary air to the furnace;
Dividing the secondary air flow channel located on the right and left sides of the fuel gas flow channel into an inner flow channel adjacent to the fuel gas flow channel and an outer flow channel disposed outside the inner flow channel; A combustion burner comprising: a pair of adjustment mechanisms that adjust the flow rate of secondary air flowing through the inner flow path to be lower than the flow rate of secondary air flowing through the outer flow path. The adjustment mechanism is
The secondary air flow path is arranged on the front end side of the secondary air flow path located on the right and left sides of the fuel gas flow path so as to extend along the axis, and the secondary air flow path is defined as the inner flow path and the outer flow. A pair of partitions that divide into roads;
A pair of adjusting portions disposed on the proximal end side of the secondary air flow path and connected to the pair of partition walls,
The partition is arranged such that an opening area of the inner flow path to the furnace is larger than an opening area of the outer flow path to the furnace,
The combustion burner according to claim 1, wherein the adjustment unit adjusts the flow rate of the secondary air flowing into the inner flow path to be smaller than the flow rate of the secondary air flowing into the outer flow path.   The adjustment unit gradually increases the cross-sectional area of the inner flow path from the upstream side to the downstream side of the secondary air flow path, and gradually decreases the flow path cross-sectional area of the outer flow path. The combustion burner according to claim 2, wherein the combustion burner is a plate-like member to be arranged.   The combustion burner according to claim 2, wherein the adjustment portion is a plate-like member formed so as to block a part of the inflow portion into the inner flow path. The adjustment mechanism is
A pair of partition walls disposed on the front end side of the secondary air flow channel located on the right and left sides of the fuel gas flow channel so as to extend along the axis,
The partition wall has an opening area of the inner flow path to the furnace larger than an opening area of the outer flow path to the furnace, and a flow rate of secondary air flowing into the inner flow path is the outer flow path. The combustion burner according to claim 1, wherein the combustion burner is disposed so as to be smaller than a flow rate of the secondary air flowing into the.   The combustion burner according to any one of claims 1 to 5, further comprising a speed reduction mechanism that reduces a flow velocity of the secondary air that flows through the secondary air flow channel positioned above and below the fuel gas flow channel. . A furnace installed along the vertical direction and formed by four wall surfaces;
The combustion burner according to any one of claims 1 to 3, wherein the combustion burner is installed for each of the four wall surfaces of the furnace.
The boiler in which the combustion burner blows the fuel gas at an angle with respect to the center of the furnace and forms a swirling flow that swirls around the center of the furnace.

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