WO2020234965A1

WO2020234965A1 - Solid fuel burner

Info

Publication number: WO2020234965A1
Application number: PCT/JP2019/019911
Authority: WO
Inventors: 木山　研滋; 健一越智; 昌平水戸; 恒輔北風; 嶺　聡彦
Original assignee: 三菱日立パワーシステムズ株式会社
Priority date: 2019-05-20
Filing date: 2019-05-20
Publication date: 2020-11-26

Abstract

Provided is a solid fuel burner such that it is possible to reduce unburned content and CO while suppressing generation of NOx. This solid fuel burner comprises: a solid fuel nozzle (10) that ejects a fluid mixture of solid fuel and primary air; a secondary air nozzle (11) that ejects secondary air; a tertiary air nozzle (12) that ejects tertiary air; a secondary air guide member (34) that guides the flow of secondary air outward in the radial direction; and one or more tertiary air guide members (20) that guide the flow of tertiary air outward in the radial direction. This solid fuel burner is equipped with a contraction flow formation member (60) that narrows the cross-sectional area of a secondary air flow path. The outer diameter (L2) of the secondary air guide member is formed smaller than the inner diameter (L1) of the outer peripheral wall of the secondary air nozzle. The leading end position (X2) of the tertiary air guide member is closer to the furnace side than the leading end position (X1) of the secondary air guide member. The solid fuel nozzle, the secondary air guide member, and the contraction flow formation member are configured so as to be integrally withdrawable from a burner throat.

Description

Solid fuel burner

The present invention relates to a solid fuel burner that burns solid fuels such as pulverized coal and biomass.

As a background technique in the present technical field, Patent Document 1 states that "a secondary air nozzle for ejecting secondary air is concentrically provided on the outside of a pulverized coal nozzle for ejecting a mixture of pulverized coal and primary air. A tertiary air nozzle that ejects tertiary air is provided concentrically on the outside of the secondary air nozzle, and a pipe expansion portion is provided at the tip of a partition wall that separates the secondary air flow path and the tertiary air flow path. In the burner, an obstacle having a plane substantially perpendicular to the flow of primary air and a guide plate having a plane substantially perpendicular to the flow of secondary air are provided at the tip of the partition partition separating the pulverized coal nozzle and the secondary air nozzle. The plane of the obstacle is located upstream of the plane of the guide plate in the axial direction of the pulverized coal nozzle, and the plane of the guide plate is in the axial direction of the pulverized coal nozzle from the tip of the tube expansion portion. It is provided so as to protrude to the downstream side of the. "

According to Patent Document 1, by deflecting the flow of the secondary air outward in the radial direction by the guide plate, the reducing flame region having a low oxygen concentration formed by the primary air can be enlarged. As a result, the generation of NOx is suppressed.

Japanese Patent No. 3986182

However, if the reducing flame region with a low oxygen concentration is enlarged, the mixing of the solid fuel with the secondary air and the tertiary air becomes slow, so that the unburned content and CO tend to increase. Therefore, in the solid fuel burner described in Patent Document 1, further ingenuity is required in order to further reduce the unburned content and CO.

An object of the present invention is to provide a solid fuel burner capable of reducing unburned components and CO while suppressing the generation of NOx.

In order to achieve the above object, a typical invention is a solid fuel burner inserted into a burner throat drilled in a wall of a furnace, and a solid that ejects a mixed fluid of solid fuel and primary air. A fuel nozzle, a secondary air nozzle provided concentrically with the solid fuel nozzle on the outside of the solid fuel nozzle and ejecting secondary air, and a secondary air nozzle concentric with the secondary air nozzle on the outside of the secondary air nozzle. A tertiary air nozzle that ejects tertiary air, a secondary air guiding member that is located on the outer periphery of the tip of the solid fuel nozzle and guides the flow of secondary air outward in the radial direction, and the tertiary air. A solid with one or more tertiary air guiding members located at the tip of the nozzle that guide the flow of tertiary air radially outward at a first angle with respect to the central axis of the solid fuel burner. The fuel burner includes a contraction forming member which is arranged on the upstream side of the secondary air guide member with respect to the flow direction of the secondary air and narrows the cross-sectional area of the flow path through which the secondary air flows. The outer diameter of the air guide member is formed smaller than the inner diameter of the outer peripheral wall of the secondary air nozzle, and the tip position of the tertiary air guide member in the axial direction of the solid fuel burner is the tip position of the secondary air guide member. It is characterized in that the solid fuel nozzle, the secondary air guide member, and the contraction forming member are integrally capable of being pulled out from the burner throat on the furnace side.

According to the present invention, unburned components and CO can be reduced while suppressing the generation of NOx. Issues, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

It is the schematic of the solid fuel burner which concerns on 1st Embodiment of this invention. It is an enlarged view of the part D shown in FIG. It is a figure which shows the state which the nozzle tip portion of the solid fuel burner which concerns on 1st Embodiment of this invention is pulled out. It is a figure which shows the air flow of the nozzle tip region of the solid fuel burner which concerns on 1st Embodiment of this invention. It is a figure which shows the air flow in the nozzle tip region of the conventional solid fuel burner. FIG. 5 is a schematic view of a solid fuel burner having a plurality of guide sleeves according to a modification of the first embodiment of the present invention. It is the schematic of the solid fuel burner which concerns on 2nd Embodiment of this invention. It is a figure which shows the air flow of the nozzle tip of the solid fuel burner which concerns on 2nd Embodiment of this invention. It is a figure which shows the air flow in the nozzle tip region of the solid fuel burner which does not provide a seal air introduction plate. It is the schematic of the solid fuel burner which concerns on 3rd Embodiment of this invention. It is the schematic of the solid fuel burner which concerns on 4th Embodiment of this invention. It is a figure which shows the air flow of the nozzle tip of the solid fuel burner which concerns on 4th Embodiment of this invention. It is the schematic of the solid fuel burner which concerns on 5th Embodiment of this invention. FIG. 5 is a schematic view of a solid fuel burner having a plurality of guide sleeves according to a modification of the second to fifth embodiments of the present invention. It is the schematic of the solid fuel burner which concerns on 6th Embodiment of this invention.

Hereinafter, each embodiment of the solid fuel burner according to the present invention will be described with reference to the drawings. The solid fuel burner according to each embodiment is a single-stage combustion type boiler device having no opening (after-airport) for supplying only air to the upper part of the burner in the fireplace, or a two-stage combustion type boiler having an after-airport. Applies to the device.

[First Embodiment]
First, the solid fuel burner 5-1 according to the first embodiment of the present invention will be described. FIG. 1 is a schematic view of the solid fuel burner 5-1 according to the first embodiment, and FIG. 2 is an enlarged view of a portion D shown in FIG. As shown in FIG. 1, the solid fuel burner 5-1 is inserted in the horizontal direction with respect to the burner throat 28 whose nozzle tip (burner outlet side) is bored in the water wall 19 which is the wall portion of the furnace 2. In this way, it is attached to the water wall 19 of the fireplace 2. The burner throat 28 is arranged from the burner 5-1 side (outside of the water wall 19) to the furnace 2 side (outside of the water wall 19) of the water wall 19 so that the inner peripheral surface thereof is inclined at a second angle θ2 with respect to the burner central axis C. It is an opening formed by expanding the diameter toward the inside of the water wall 19).

The solid fuel burner 5-1 has a fuel nozzle (solid fuel nozzle) 10. The fuel nozzle 10 is a tubular member whose base side is connected to a fuel-containing fluid pipe (not shown), and a solid-air two-phase flow (mixed fluid 13) of solid fuel and primary air (conveyed gas) is inside the fuel nozzle 10. It becomes a flowing primary air flow path 10a. The solid fuel may be a solid or powder such as coal (pulverized coal) or biomass, or a mixture thereof, and in the present embodiment, an example in which pulverized coal is used as the solid fuel is shown. In the following description, the mixed fluid 13 may be referred to as the primary air 13.

A secondary air nozzle 11 having a secondary air flow path 11a through which the secondary air 14 flows is provided on the outside (outer circumference side) of the fuel nozzle 10, and a tertiary air nozzle 11 is provided on the outside (outer circumference side) of the secondary air nozzle 11. A tertiary air nozzle 12 having a tertiary air flow path 12a through which the air 15 flows is provided. The secondary air 14 and the tertiary air 15 are combustion gases, and air is usually used in the same manner as the primary air which is a transport gas, but with combustion exhaust gas, oxygen-rich gas, or these gases and air. A mixed gas of two or more can also be applied.

When the fuel nozzle 10, the secondary air nozzle 11, and the tertiary air nozzle 12 are viewed from the front of the burner outlet side (fire furnace 2 side), the annular secondary air nozzle 11 is concentric with the fuel nozzle 10 as the center. The annular tertiary air nozzles 12 are arranged concentrically on the outside of the secondary air nozzles 11. In the first embodiment, the swirler 22 for imparting swirl to the tertiary air 15 is arranged at the inlet portion of the tertiary air flow path 12a, but it is also possible to configure the swirler 22 not to be provided. ..

Inside the fuel nozzle 10, a start burner (oil gun) 16 penetrating the fuel nozzle 10 is provided, and is used for preheating and assisting combustion when the boiler is started or when the boiler load is low. Depending on the configuration of the solid fuel burner 5-1, the start burner 16 may not be installed.

A flame insulator for forming a circulating flow 51 (see FIG. 4A) between the spouts of the primary air 13 and the secondary air 14 at the open end of the fuel nozzle 10 (that is, the outlet on the furnace 2 side). 23 is provided. The flame retainer 23 is provided on the outer periphery of the tip of the fuel nozzle 10 so as to form a circulating flow 51 on the downstream side of the flame retainer 23 to enhance ignitability and flame retention effect.

The start-up burner 16, the fuel nozzle 10, the secondary air nozzle 11, and the tertiary air nozzle 12 each eject ejecta toward the inside of the furnace 2. Further, the starting burner 16, the fuel nozzle 10, the secondary air nozzle 11, and the tertiary air nozzle 12 are arranged in a wind box 25 surrounding the burner throat 28. Combustion air is supplied through the windbox 25. The partition wall 18 is a wall-shaped member that separates the internal space of the windbox 25 from the outside of the furnace 26. Of the partition walls 18, the front plate 27 on which the fuel nozzle 10 is installed is detachably supported on the partition wall 18 with bolts, screws, hooks, etc. so that it can be integrally pulled out from the fuel nozzle 10 during burner maintenance. Has been done.

A guide sleeve 20 (in a divergent shape) that expands in the radial direction with respect to the central axis C of the burner is provided at the tip of the partition wall that separates the secondary air flow path 11a and the tertiary air flow path 12a. The guide sleeve (tertiary air guide member) 20 is inclined outward in the radial direction at a first angle θ1 with respect to the burner central axis C. The first angle θ1 is substantially the same as the second angle θ2, which is the inclination angle of the inner peripheral surface of the burner throat 28 described above, and is set within the range of 10 degrees to 40 degrees. More preferably, the first angle θ1 and the second angle θ2 are in the range of 20 to 30 degrees.

When the first angle θ1 and the second angle θ2 exceed 40 degrees, the secondary air 14 and the tertiary air 15 flow too much outward in the radial direction, so that the reducing flame region due to the primary air 13 becomes too large. , The effect of reducing unburned matter and CO, which are the residues of solid fuel, cannot be expected so much. Further, when the first angle θ1 and the second angle θ2 are less than 10 degrees, the reducing flame region becomes small, so that the effect of reducing NOx cannot be expected so much. Therefore, the first angle θ1 and the second angle θ2 are preferably in the range of 10 to 40 degrees, and when set in the range of 20 to 30 degrees, the effect of reducing unburned content and CO of solid fuel and NOx It is more preferable because the reduction effect of the above can be balanced. The guide sleeve 20 may be located on the outer peripheral side of the secondary air nozzle 11 and at the tip of the tertiary air nozzle 12, regardless of where the guide sleeve 20 is attached. For example, the guide sleeve 20 may be fixed to the tip of the outer peripheral outlet of the secondary air nozzle 11, or directly to the burner throat 28 with the guide sleeve 20 positioned at the tip of the outer peripheral outlet of the secondary air nozzle 11. It may be fixed indirectly.

A ring-shaped guide ring (secondary air guide member) 34 extending outward in the radial direction is arranged on the outer peripheral portion of the tip of the flame holder 23. The guide ring 34 has a substantially vertical plane substantially orthogonal to the burner central axis C.

Further, in the flame holder 23, a plate-shaped fin member 36 extending along the flow direction of the secondary air 14 is installed in the secondary air flow path 11a. A plurality of fin members are arranged at intervals along the circumferential direction of the flame holder 23, and are made of a radial plate material.

A contraction forming member 60 is arranged on the upstream side of the fin member 36. As shown in FIG. 2, the contraction forming member 60 has an upstream wall portion 60a extending in the radial direction with respect to the burner central axis C and a downstream inner end in the radial direction of the upstream wall portion 60a in the flow direction of the secondary air 14. It has a tubular wall portion 60b extending to the side. Therefore, in the first embodiment, the contraction forming member 60 forms an annular gas flow path having an L-shaped cross section along the axial direction.

The contraction forming member 60 has a tubular wall portion 60b fixedly supported by the fin member 36 and is integrally movable with the fin member 36. A small gap and play that can be moved are formed between the contraction forming member 60 and the secondary air nozzle 11.

The contraction forming member 60 is installed on the outer peripheral side of the secondary air flow path 11a of the secondary air nozzle 11, so that the cross section of the flow path is once narrowed in the radial central axis direction. That is, the cross-sectional area of the secondary air flow path 11a is narrowed. After passing through the contraction forming member 60, the flow reaches the guide ring 34 in a compressed state, and forms a flow that spreads the direction of the flow outward from the burner central axis C. The contraction forming member 60 is a member separated from the secondary air nozzle 11 and is supported from the flame holder 23 side. The contraction forming member 60 is preferably composed of a ring-shaped member that is uniform in the entire circumferential direction, but may be divided into a plurality of members in the circumferential direction. Further, the contraction forming member 60 is preferably formed integrally with the flame holder 23, but may be formed separately.

For convenience of illustration, the above-mentioned minute gaps and play formed between the outer peripheral portion of the contraction forming member 60 and the inner wall surface of the secondary air nozzle 11 appear to be large, but they are actually extremely small. The flow rate of the secondary air 14 that short-passes here is almost negligible. Further, in order to increase the pressure loss in the gap, it is desirable that the outer peripheral surface of the contraction forming member 60 (the surface facing the inner wall surface of the secondary air nozzle 11) has a sufficient length in the axial direction. Further, the cross-sectional shape of the contraction forming member 60 is not limited to the L-shape shown in the drawing, and the above-mentioned outer peripheral surface (the surface facing the inner wall surface of the secondary air nozzle 11) is extended to form a rectangular shape, a pentagonal shape, or the like. Various are applicable (see FIG. 10).

Explaining the positional relationship between the guide sleeve 20 and the guide ring 34 in detail, as shown in FIG. 2, the guide sleeve 20 overlaps the guide ring 34 in the direction (axial direction) along the central axis C of the burner to guide the guide. The tip position X2 of the guide sleeve 20 is closer to the furnace 2 side (right side in FIG. 2) than the tip position X1 of the ring 34. In other words, the tip position X2 is on the downstream side of the air flow than the tip position X1. Then, the distance between the front side surface of the guide ring 34 (the side surface of the guide ring 34 facing the fireplace 2 and the side surface opposite to the side surface facing the furnace 2) and the tip of the inner peripheral surface of the guide sleeve 20, that is, the guide sleeve 20 guides. Let A be the length that overlaps the ring 34, and set the distance between the tip of the inner peripheral surface of the guide sleeve 20 and the outer peripheral end of the guide ring 34, that is, the gap in the height direction between the guide sleeve 20 and the guide ring 34. When B is set, the relationship between the length A and the gap B is set so as to satisfy A> 0.5 × B. The tip position X2 of the guide sleeve 20 and the tip position X1 of the guide ring 34 are housed in the burner throat 28 and do not project from the inner peripheral surface of the water wall 19 toward the inside of the fireplace 2.

Explaining the dimensional relationship between the inner diameter L1 of the secondary air nozzle 11, the outer diameter L2 of the guide ring 34, and the inner diameter L3 of the contraction forming member 60, as shown in FIG. 2, with respect to the inner diameter L1 of the secondary air nozzle 11. Therefore, the outer diameter L2 of the guide ring 34 is set to be smaller (L2 <L1). In the first embodiment, the outer diameter L2 of the guide ring 34 and the outer diameter of the contraction forming member 60 are set to the same outer diameter L2, but the outer diameter of the contraction forming member 60 is the secondary air nozzle 11. It suffices if it is smaller than the inner diameter of the guide ring 34, and the magnitude relationship with the outer diameter L2 of the guide ring 34 does not matter.

Further, in the first embodiment, the outer diameter L2 is set smaller than the outer diameter (inner diameter of the partition wall 18) L4 (see FIG. 1) of the front plate 27 (L2 <L4). Further, in the first embodiment, the inner diameter (distance between the burner center axis C and the cylinder wall portion 60b) L3 of the contraction forming member 60 is set smaller than the outer diameter L2 of the guide ring 34 (L2>. L3). That is, in the first embodiment, L1> L2> L3 is set.

FIG. 3 is a diagram showing a state in which the nozzle tip portion of the solid fuel burner 5-1 according to the first embodiment of the present invention is pulled out. As described above, since the solid fuel burner 5-1 according to the first embodiment has a configuration that satisfies the dimensional relationship of L1> L2> L3, the front plate 27 is removed from the partition wall 18 and the fuel nozzle 10 is pulled out. In this case, the fuel nozzle 10, the flame holder 23, the guide ring 34, the fin member 36, and the contraction forming member 60 are integrally configured to be able to be pulled out toward the outside of the furnace 26.

If the fuel nozzle 10 and the like are not completely pulled out and the contraction forming member 60 can be pulled out to a certain extent inside the furnace (inside the windbox 25) from the partition wall 18, the outer diameter L4 of the front plate 27 is removed. The diameter can be set smaller than L2, and the fuel nozzle 10 can be moved with respect to the partition wall 18 without providing the front plate 27.

Next, the air flow in the nozzle tip region of the solid fuel burner 5-1 according to the first embodiment will be described in comparison with the prior art. First, the air flow in the nozzle tip region of the conventional solid fuel burner will be described with reference to FIG. 4B. FIG. 4B is a diagram showing an air flow in the nozzle tip region of a conventional solid fuel burner. In the configuration of the prior art shown in FIG. 4B, the tip position X1 of the guide ring 34 is closer to the fireplace 2 than the tip position X2 of the guide sleeve 20. That is, the positional relationship is opposite to that of the first embodiment, and the guide sleeve 20 does not overlap the guide ring 34. The first angle θ1 of the guide sleeve 20 is set to be the same as the first angle θ1 of the first embodiment.

As shown in FIG. 4B, in the conventional solid fuel burner configuration, the secondary air 14 collides with the guide ring 34 and largely turns outward in the radial direction. At that time, since the guide sleeve 20 does not overlap the guide ring 34, the secondary air 14 flows largely outward in the radial direction together with the tertiary air 15. As a result, the reducing flame region 50b becomes large, and although the effect of reducing NOx can be expected, the effect of reducing the unburned content and CO of the solid fuel is low.

Next, the air flow in the nozzle tip region of the solid fuel burner 5-1 according to the first embodiment will be described with reference to FIG. 4A. FIG. 4A is a diagram showing an air flow in the nozzle tip region of the solid fuel burner 5-1. As shown in FIG. 4A, the primary air 13 is ejected from the fuel nozzle 10 into the furnace 2. The secondary air 14 flows in the secondary air nozzle 11 and collides with the guide ring 34 of the flame holder 23, and the flow direction is deflected outward in the radial direction. Since the tip position X2 of the guide sleeve 20 is located closer to the fireplace 2 than the tip position X1 of the guide ring 34, the secondary air 14 that collides with the guide ring 34 exceeds the guide ring 34 of the guide sleeve 20. It flows along the inner peripheral surface of the wrapping portion (portion A in FIG. 2) and is ejected into the fireplace 2 toward the outside in the radial direction at a first angle θ1 with respect to the central axis C of the burner. The tertiary air 15 flows through the tertiary air nozzle 12, and while turning toward the outer peripheral side along the guide sleeve 20, inside the furnace 2 toward the outside in the radial direction at a first angle θ1 with respect to the burner central axis C. Squirt into.

As described above, since the tip position X2 of the guide sleeve 20 is closer to the fireplace 2 than the tip position X1 of the guide ring 34, the radial outward deflection of the secondary air 14 is suppressed by the guide sleeve 20. Further, the first angle θ1 of the guide sleeve 20 is set to 10 to 40 degrees. Therefore, the secondary air 14 and the tertiary air 15 are deflected radially outward by the first angle θ1 of the guide sleeve 20 and are ejected into the fireplace 2. As a result, the reducing flame region 50a can be narrowed as compared with the above-mentioned conventional technique, and the generation of unburned components and CO of the solid fuel can be reduced.

As described above, according to the solid fuel burner 5-1 according to the first embodiment, since the guide sleeve 20 is configured to overlap the guide ring 34, the secondary air 14 and the tertiary air 15 are in the radial direction. The flow to the outside can be suppressed. As a result, the reduction flame region 50a due to the primary air 13 becomes smaller than before, and the generation of unburned components and CO of the solid fuel can be reduced. Moreover, by setting the first angle θ1 of the guide sleeve 20 in the range of 10 to 40 degrees, more preferably in the range of 20 to 30 degrees, the effect of reducing the unburned content and CO of the solid fuel and NOx It is possible to balance the reduction effect of.

Further, the relationship between the length A in which the guide sleeve 20 overlaps the guide ring 34 and the gap B in the height direction between the guide sleeve 20 and the guide ring 34 satisfies A> 0.5 × B. Since it is set, the secondary air 14 can flow along the guide sleeve 20 while the guide sleeve 20 surely suppresses the secondary air 14 from going outward in the radial direction. Therefore, a suitable reducing flame region 50a can be formed, and the generation of unburned components and CO of the solid fuel can be effectively suppressed.

Further, since the flow of the secondary air 14 and the tertiary air 15 to the outside in the radial direction can be suppressed, the solid fuel ejected from the fuel nozzle 10 and the secondary air 14 and the tertiary air 15 are mixed faster. As a result, since the flame temperature rises, heat absorption into the water wall 19 of the fireplace 2 increases, the gas temperature at the outlet of the fireplace 2 can be lowered, and it is also effective in suppressing slugging. In addition, slugging means that the ash melted by combustion adheres to the furnace wall and the heat transfer tube to reduce the heat collection and increase the pressure loss in the furnace.

Further, since the outer diameter L2 of the guide ring 34 and the outer diameter of the contraction forming member 60 are set smaller than the inner diameter L1 of the secondary air nozzle 11, the solid fuel burner 5- In the step of disassembling 1, the guide ring 34 can be pulled out together with the fuel nozzle 10 and the like without being caught by the secondary air nozzle 11 (see FIG. 3). This improves maintainability.

Further, since the contraction forming member 60 is arranged on the upstream side of the guide ring 34, when the secondary air 14 passes through the contraction forming member 60, the flow velocity becomes high and collides with the guide ring 34 at high speed. Then, it deflects outward in the radial direction. Therefore, in the configuration of the first embodiment, even if the outer diameter L2 of the guide ring 34 is small, the radial deflection of the ejected secondary air 14 becomes strong, and the circulation formed on the downstream side of the guide ring 34. The flow is secured. As a result, the flame is stabilized and low NOx performance is maintained.

Next, an example of a solid fuel burner 5-2 having a plurality of guide sleeves 20 will be described according to a modified example of the first embodiment of the present invention. FIG. 5 is a schematic view of the solid fuel burner 5-2 of this example. The same components as those in the case of one guide sleeve 20 are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 5, the solid fuel burner 5-2 of this example is characterized in that a plurality (for example, two) of guide sleeves 20 are provided at intervals in the radial direction of the tertiary air nozzle 12. The two guide sleeves 20 are held at predetermined intervals by spacers (not shown), and are also fixed by bolts or welds (not shown). The first angle θ1 of the two guide sleeves 20 is substantially the same, for example, in the range of 10 degrees to 40 degrees, and more preferably in the range of 20 degrees to 30 degrees. Further, the tip positions X2 of the two guide sleeves 20 in the axial direction are both substantially the same position, and are closer to the fireplace 2 than the tip position X1 of the guide ring 34.

In the solid fuel burner 5-2 of this example, the tertiary air 15 is guided outward in the radial direction by a first angle θ1 by the plurality of guide sleeves 20, so that, for example, the radial width of the outlet portion of the tertiary air nozzle 12 (That is, when the distance between the tip of the partition partition separating the secondary air flow path 11a and the tertiary air flow path 12a and the burner throat 28 is large), the flow direction of the tertiary air 15 is surely restricted. Is possible. As a result, as compared with the case where there is only one guide sleeve 20, the guide sleeve 20 can reliably supply the tertiary air 15 into the furnace 2 at a predetermined angle θ1, and the effect of reducing the unburned content and CO of the solid fuel is secured. To.

[Second Embodiment]
Next, the solid fuel burner 5-3 according to the second embodiment of the present invention will be described. FIG. 6 is a schematic view of the solid fuel burner 5-3 according to the second embodiment. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In the second embodiment, it is assumed that the second angle θ2 of the burner throat 28 is larger than the first angle θ1 of the guide sleeve 20. For example, it is assumed that the second angle θ2 of the burner throat 28 of the existing boiler device is about 45 degrees, and the solid fuel burner 5-3 is installed in the burner throat 28.

As shown in FIG. 6, the solid fuel burner 5-3 according to the second embodiment is provided with a seal air introduction plate (seal air introduction plate) at a position between the guide sleeve 20 and the burner throat 28 in addition to the configuration of the first embodiment. It is characterized in that the seal air introduction member) 40 is provided. The seal air introduction plate 40 is arranged so as to be inclined outward by a third angle θ3 from the burner central axis C in the radial direction, and the third angle θ3 is substantially the same as the first angle θ1. That is, the guide sleeve 20 and the seal air introduction plate 40 are inclined at substantially the same angle. The first angle θ1 and the third angle θ3 are set in the range of, for example, 10 degrees to 40 degrees, and more preferably in the range of 20 degrees to 30 degrees. The guide sleeve 20 and the seal air introduction plate 40 are provided at intervals in the radial direction by spacers (not shown), and are also fixed by bolts or welding (not shown). The spacing of the seal air introduction plate 40 by the spacer and the fixing by bolts or welding may be performed from the member side continuous with the burner throat 28 or the burner throat 28. Further, the tip position X3 of the seal air introduction plate 40 in the axial direction is set to be substantially the same as the tip position X2 of the guide sleeve 20.

Next, the air flow in the nozzle tip region of the solid fuel burner 5-3 according to the second embodiment will be described in comparison with the configuration in which the seal air introduction plate 40 is not provided. First, the air flow in the solid fuel burner not provided with the seal air introduction plate 40 will be described with reference to FIG. 7B. FIG. 7B is a diagram showing the air flow in the nozzle tip region of the solid fuel burner not provided with the seal air introduction plate 40, and the flow of the secondary air 14 and the tertiary air 15 is indicated by a solid arrow, and the gas in the furnace 2 is shown. The flow of each is indicated by a broken line arrow.

As shown in FIG. 7B, the secondary air 14 flows in between the flame holder 23 and the guide sleeve 20 through the secondary air flow path 11a, collides with the guide ring 34, and is spread outward in the radial direction. Then, the secondary air 14 collides with the inner peripheral surface of the guide sleeve 20 and is supplied to the fireplace 2 at a substantially spreading angle (first angle θ1) of the guide sleeve 20.

After the flow of the tertiary air 15 is throttled in the tertiary air flow path 12a, the tertiary air 15 is supplied to the furnace 2 along the outer peripheral side of the guide sleeve 20 at an inclination of the guide sleeve 20 (first angle θ1). The secondary air 14 and the tertiary air 15 are supplied to the fireplace 2 at an inclination of the guide sleeve 20 (first angle θ1) with the guide sleeve 20 interposed therebetween, and after the outlet of the guide sleeve 20, the secondary air 14 and the tertiary air 15 are supplied to the furnace 2. The tertiary air 15 has an integrated flow.

Here, as described above, since the second angle θ2 of the burner throat 28 is about 45 degrees and is larger than the first angle θ1 (for example, 10 degrees to 40 degrees) of the guide sleeve 20, the secondary air 14 A circulating flow 52 is formed between the flow in which the secondary air 15 and the tertiary air 15 are integrated and the spreading portion of the burner throat 28 by an accompanying phenomenon in which the secondary air 14 and the tertiary air 15 are drawn into the integrated flow. In the internal space of the furnace 2 near the burner, a large circulating flow 53 attracted by the integrated flow of the secondary air 14 and the tertiary air 15 is formed, and a part of the circulating flow 52 is formed in the burner throat 28. Most of the circulating flow 53 is accompanied by a flow in which the secondary air 14 and the tertiary air 15 are integrated.

The circulating flow 53 in the furnace 2 contains molten combustion ash, and a part of it also flows into the circulating flow 52 formed in the vicinity of the burner throat 28, so that the seal air introduction plate 40 is not provided. In this case, the molten ash may gradually adhere to the burner throat 28 to form a large clinker. When a large clinker is formed, there is a risk that the secondary air 14 and the tertiary air 15 may change the flow state of the integrated flow or block the air flow path.

Next, the air flow in the nozzle tip region of the solid fuel burner 5-3 according to the second embodiment will be described with reference to FIG. 7A. FIG. 7A is a diagram showing an air flow at the tip of the nozzle of the solid fuel burner 5-3 according to the second embodiment. Since the solid fuel burner 5-3 according to the second embodiment includes the seal air introduction plate 40, the air flow in the nozzle tip region is different from that in FIG. 7B. More specifically, in the solid fuel burner 5-3 according to the second embodiment, the secondary air 14 and the tertiary air 15 are integrated and ejected at an angle equivalent to the spreading angle of the guide sleeve 20. Since the seal air introduction plate 40 has the same spreading angle as the guide sleeve 20, the circulation flow 52 is not formed inside the seal air introduction plate 40.

A seal air 55 (thick line in the figure), which is a part of the tertiary air 15, is introduced between the seal air introduction plate 40 and the burner throat 28, and is spread outward in the radial direction by the seal air introduction plate 40, and the burner throat It flows between 28 and is supplied into the furnace 2. The flow of the seal air 55 also suppresses the formation of the circulation zone of the burner throat 28. After the seal air 55 is supplied into the furnace 2, it is accompanied by a flow in which the secondary air 14 and the tertiary air 15 are integrated. Along with the flow of the sealed air 55 in the fireplace 2, the circulation flow (return flow) 53 of the high-temperature gas in the fireplace 2 is also accompanied by the integrated flow of the secondary air 14 and the tertiary air 15. The inflow of the molten ash in the high temperature gas in 2 to the burner side can be suppressed, and the ash can be suppressed from adhering to the vicinity of the burner throat 28.

As described above, according to the solid fuel burner 5-3 according to the second embodiment, the reducing flame region 50a can be narrowed as in the first embodiment, so that the unburned content and CO of the solid fuel can be reduced. Moreover, even if the solid fuel burner attached to the existing boiler device is replaced with the solid fuel burner 5-3 according to the second embodiment, since the seal air introduction plate 40 is provided, the vicinity of the burner throat 28 can be reached. Ash adhesion is suppressed. That is, the solid fuel burner 5-3 according to the second embodiment has a structure suitable for modifying an existing boiler device.

[Third Embodiment]
Next, the solid fuel burner 5-4 according to the third embodiment of the present invention will be described. FIG. 8 is a schematic view of the solid fuel burner 5-4 according to the third embodiment. The same configurations as those of the first and second embodiments are designated by the same reference numerals, and the description thereof will be omitted. As shown in FIG. 8, the solid fuel burner 5-4 according to the fourth embodiment is the rear end portion (tertiary air 15) of the seal air introduction plate 40 in addition to the solid fuel burner 5-3 according to the second embodiment. A feature is that a seal air guide cylindrical portion (seal air guide member) 44 is provided at the upstream end of the flow.

As shown in FIG. 8, since the tertiary air 15 is introduced in the direction perpendicular to the central axis C of the burner, the tertiary air 15 easily flows between the guide sleeve 20 and the seal air introduction plate 40. Therefore, in the fourth embodiment, the seal air induction cylindrical portion 44 is provided in order to more reliably guide the seal air outward in the radial direction of the seal air introduction plate 40. As a result, a part of the tertiary air 15 is surely guided as the sealing air to the flow path between the sealing air introduction plate 40 and the burner throat 28, and the generation of the circulating flow 52 (see FIG. 7B) is prevented. .. This has the advantage that ash is less likely to adhere to the vicinity of the burner throat 28. The length of the seal air induction cylindrical portion 44 can be arbitrarily designed so that the optimum seal air can be supplied, and may project into the space on the side where the swirler 22 is installed.

[Fourth Embodiment]
Next, the solid fuel burner 5-5 according to the fourth embodiment of the present invention will be described. FIG. 9 is a schematic view of the solid fuel burner 5-5 according to the fourth embodiment. The same configurations as those of the first to third embodiments are designated by the same reference numerals and the description thereof will be omitted. As shown in FIG. 9, the solid fuel burner 5-5 according to the fourth embodiment is the tip portion of the seal air introduction plate 40 (of the tertiary air 15) in addition to the solid fuel burner 5-4 according to the third embodiment. A feature is that a seal air deflection plate (seal air deflection member) 42 is provided at the downstream end of the flow). The seal air deflecting plate 42 extends radially outward from the tip end portion of the seal air introduction plate 40, and has a plane substantially perpendicular to the burner central axis C.

Next, the air flow in the nozzle tip region of the solid fuel burner 5-5 according to the fourth embodiment will be described with reference to FIG. FIG. 10 is a diagram showing an air flow at the tip of the nozzle of the solid fuel burner 5-5 according to the fourth embodiment. In the solid fuel burner 5-5 according to the fourth embodiment, the seal air induced by the seal air induction cylindrical portion 44 is brought to the burner central axis C by the seal air introduction plate 40 by a third angle θ3 (≈θ1). On the other hand, the air flows outward in the radial direction, collides with the seal air deflection plate 42, and is further deflected outward in the radial direction. As a result, the generation of the circulating flow 52 (see FIG. 7B) can be prevented more reliably as compared with the second or third embodiment, and the adhesion of ash to the vicinity of the burner throat 28 can be further prevented.

[Fifth Embodiment]
Next, the solid fuel burner 5-6 according to the fifth embodiment of the present invention will be described. FIG. 11 is a schematic view of the solid fuel burner 5-6 according to the fifth embodiment. The same configurations as those of the first to fourth embodiments are designated by the same reference numerals and the description thereof will be omitted. As shown in FIG. 11, in the solid fuel burner 5-6 according to the fifth embodiment, the tip position X3 of the seal air introduction plate 40 is located on the furnace 2 side in the axial direction from the tip position X2 of the guide sleeve 20. The point is different from the solid fuel burner 5-5 according to the fourth embodiment. However, the tip position X3 of the seal air introduction plate 40 does not protrude inward from the inner peripheral surface of the water wall 19 of the fireplace 2.

According to the fifth embodiment, since the tip position X3 of the seal air introduction plate 40 is slightly closer to the fireplace 2 than the tip position X2 of the guide sleeve 20, the secondary air 14 and the tertiary air 15 are radially outward. Since the spread of the fuel is further suppressed, the reducing flame region 50a can be surely narrowed as compared with the fourth embodiment, and the effect of reducing the unburned content and CO of the solid fuel is further enhanced.

Next, an example of a solid fuel burner 5-7 having a plurality of guide sleeves 20 will be described according to a modified example of the second to fifth embodiments of the present invention. FIG. 12 is a schematic view of the solid fuel burner 5-7 of this example. The same configuration as in the case of one guide sleeve 20 is designated by the same reference numerals and the description thereof will be omitted. As shown in FIG. 12, the solid fuel burner 5-7 of this example has a plurality of guide sleeves 20 in the radial direction (for example, two) in addition to the configuration of the solid fuel burner 5-3 according to the second to fifth embodiments. ) The feature is that it is provided. The tip position X2 of the guide sleeve 20 and the tip position X3 of the seal air introduction plate 40 are substantially the same in the axial direction. The sealed air introduction structure of FIG. 12 is based on the second embodiment (see FIG. 6).

According to this example, since a plurality of guide sleeves 20 are provided in the radial direction, for example, when the width of the outlet portion of the tertiary air nozzle 12 in the radial direction is large (that is, the secondary air flow path 11a and the tertiary air flow path 11a). The flow direction of the tertiary air 15 can be reliably defined at (when the distance between the tip of the partition wall separating the 12a and the burner throat 28 is large). As a result, the guide sleeve 20 can surely supply the tertiary air 15 into the furnace 2 at a predetermined angle θ1, the reducing flame region 50a can be surely narrowed, and the unburned portion of the solid fuel as compared with the case where the guide sleeve 20 is one. And CO reduction effect becomes more certain.

[Sixth Embodiment]
Next, the solid fuel burner 5-8 according to the sixth embodiment of the present invention will be described. FIG. 13 is a schematic view of the solid fuel burner 5-8 according to the sixth embodiment. The same configurations as those of the first to fifth embodiments are designated by the same reference numerals and the description thereof will be omitted. As shown in FIG. 13, the solid fuel burner 5-8 according to the sixth embodiment includes the seal air introduction plate 40 and the burner throat 28 in addition to the configuration of the solid fuel burner 5-3 according to the second embodiment. A feature is that a seal air drift suppression plate (seal air drift suppression member) 48 for suppressing the drift of the seal air is further provided between them. The seal air drift suppression plate 48 is composed of, for example, a punching plate provided with a large number of holes and a plate provided with a large number of slits.

By providing the seal air drift suppression plate 48, the seal air introduced to the outside in the radial direction of the seal air introduction plate 40 becomes a uniform flow and is supplied into the furnace 2, so that the formation of the circulation flow 52 is prevented. As a result, the adhesion of ash in the vicinity of the burner throat 28 can be prevented. Further, by providing the seal air drift suppression plate 48, it is not necessary to provide the seal air deflection plate 42. That is, the seal air drift suppression plate 48 is a member that can replace the seal air deflection plate 42 used in the fourth and fifth embodiments.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention, and all the technical matters included in the technical idea described in the claims are all. It is the subject of the present invention. Although the above-described embodiment shows a suitable example, those skilled in the art can realize various alternative examples, modifications, modifications or improvements from the contents disclosed in the present specification. These are included in the technical scope described in the appended claims.

For example, the seal air introduction plate 40 and the seal air deflection plate 42 may be provided, and the seal air induction cylindrical portion 44 may not be provided. Further, although the configuration in which the first angle θ1 and the third angle θ3 are substantially the same has been described, they do not necessarily have to be the same angle as long as they are within the range of 10 degrees to 40 degrees.

1 Boiler device 2 Fireplace 5-1 to 10 Solid fuel burner 6 Spacer 7 Support 10 Fuel nozzle (solid fuel nozzle)
11 Secondary air nozzle 12 Secondary air nozzle 13 Primary air (mixed fluid)
14 Secondary air 15 Tertiary air 19 Water wall (wall)
20 Guide sleeve (tertiary air guide member)
23 Flame holder 28 Burna throat 34 Guide ring (secondary air guide member)
40 Seal air introduction plate (seal air introduction member)
42 Seal air deflector (seal air deflector)
44 Seal air induction cylinder (seal air induction member)
48 Seal air drift suppression plate (seal air drift suppression member)
50a, 50b Reduction flame region 60 Condensation forming member C Burner central axis

Claims

A solid fuel burner that is inserted into a burner throat drilled in the wall of a fireplace.
A solid fuel nozzle that ejects a mixed fluid of solid fuel and primary air,
A secondary air nozzle provided on the outside of the solid fuel nozzle concentrically with the solid fuel nozzle and ejecting secondary air,
A tertiary air nozzle, which is provided on the outside of the secondary air nozzle concentrically with the secondary air nozzle and ejects tertiary air,
A secondary air guidance member located on the outer peripheral portion of the tip of the solid fuel nozzle and guiding the flow of secondary air outward in the radial direction.
One or more tertiary air guide members located at the tip of the tertiary air nozzle and guiding the flow of tertiary air radially outward at a first angle with respect to the central axis of the solid fuel burner. In the equipped solid fuel burner
A contraction forming member is provided on the upstream side of the secondary air guidance member with respect to the flow direction of the secondary air and narrows the cross-sectional area of the flow path through which the secondary air flows.
The outer diameter of the secondary air guide member is formed to be smaller than the inner diameter of the outer peripheral wall of the secondary air nozzle.
The tip position of the tertiary air guide member in the axial direction of the solid fuel burner is closer to the fireplace than the tip position of the secondary air guide member.
A solid fuel burner characterized in that the solid fuel nozzle, the secondary air guide member, and the contraction forming member are integrally configured to be pullable from the burner throat.
In the solid fuel burner according to claim 1,
When the inner diameter of the outer peripheral wall of the secondary air nozzle is L1, the outer diameter of the secondary air guide member is L2, and the inner diameter of the contraction forming member is L3,
L1>L2> L3
A solid fuel burner characterized by having a relationship of.
In the solid fuel burner according to claim 1 or 2.
The burner throat is formed by increasing the diameter from the burner side to the furnace side of the wall portion of the furnace so that the inner peripheral surface thereof is inclined at a second angle with respect to the central axis.
The solid fuel burner, wherein the first angle is substantially the same as the second angle and is set within a range of 10 to 40 degrees with respect to the central axis.
In the solid fuel burner according to claim 3.
More preferably, the solid fuel burner is characterized in that the first angle is set within a range of 20 to 30 degrees with respect to the central axis.
In the solid fuel burner according to claim 1,
The burner throat is formed by increasing the diameter from the burner side to the furnace side of the wall portion of the furnace so that the inner peripheral surface thereof is inclined at a second angle with respect to the central axis.
The first angle is set within the range of 10 to 40 degrees with respect to the central axis.
The second angle is larger than the first angle.
A seal air introduction member for introducing a part of the tertiary air as seal air is further provided between the tertiary air guide member and the burner throat.
The seal air introduction member is a solid fuel burner characterized in that it is inclined outward in the radial direction at a third angle with respect to the central axis.
In the solid fuel burner according to claim 5.
A solid fuel burner characterized in that a seal air guiding member for guiding the sealing air to the sealing air introducing member is further provided at an upstream end portion of the tertiary air flow in the sealing air introducing member. ..
In the solid fuel burner according to claim 5 or 6.
A solid fuel burner characterized in that a seal air deflection member for deflecting the seal air to the outside in the radial direction is further provided at a tip end portion of the seal air introduction member.
In the solid fuel burner according to any one of claims 5 to 7.
The tip position of the seal air introduction member in the axial direction of the solid fuel burner is the same as the tip position of the tertiary air guide member or is closer to the furnace side than the tip position of the tertiary air guide member. ..
In the solid fuel burner according to any one of claims 5 to 8.
The solid fuel burner, characterized in that the third angle is set substantially the same as the first angle.
In the solid fuel burner according to claim 5 or 6.
A solid fuel burner, characterized in that a seal air drift suppression member for suppressing the drift of the seal air is further provided between the seal air introduction member and the burner throat.
In the solid fuel burner according to claim 10.
The seal air drift suppression member is a solid fuel burner characterized by being a plate having a large number of holes and slits formed therein.