TW201812214A - Solid fuel burner - Google Patents

Abstract

This solid fuel burner is provided with: a fuel nozzle 2 through which a fluid mixture of a solid fuel and a carrier gas flows, the opening shape of the fuel nozzle 2 being flat; a secondary air nozzle 4 that is located on the outer peripheral side of the fuel nozzle 2, a guide sleeve 13 being provided to the outer periphery of the tip of the secondary air nozzle 4, and the opening shape of the secondary air nozzle 4 being flat; and a tertiary air nozzle 7 that is located on the outer peripheral side of the secondary air nozzle 4 and comprises a horizontal part 7a and a slanted part 7b, the opening shape of the tertiary air nozzle 7 being cylindrical. On the outlet side of the solid fuel burner, inside the tertiary air nozzle 7, a guide vane 14 for guiding tertiary air to the outer peripheral side is supported by a support member 15 on the inner wall of the tertiary air nozzle 7. Due to this support configuration, the portion extracted during maintenance of the burner ends at the secondary air nozzle 4, ease of maintenance is excellent, and the gap between the guide vane 14 and the tertiary air nozzle 7 can be reduced. Therefore, as pertains to a burner configured such that combustion gas, which jets out from the outer periphery of a fuel-containing fluid stream, spreads radially outward, it is possible to provide a solid fuel burner with which increases in Nox concentration are better prevented and ease of maintenance is exceptional.

Description

Solid fuel burner

[0001] The present invention relates to a solid fuel burner, and more particularly, to a structure of a solid fuel burner that can reduce the amount of nitrogen oxides generated by combustion and has excellent ease of maintenance.

[0002] Combustion devices such as boilers that burn solid fuels such as coal (hereinafter sometimes referred to as pulverized coal) are required to reduce nitrogen oxides generated by fuel combustion for environmental reasons. (hereinafter, the description sometimes called: NO _x) concentration. [0003] Low NO _x burners on denitration reaction (removing nitrogen oxides) in the flame, the burner of known construction, of which one is discharging fuel (i.e., fuel-containing fluid ejection flow of the fuel from the nozzle ), Injecting air (ie, combustion gas) from the outer periphery of the jet containing the fuel fluid, and diffusing the air radially outward. [0004] FIG. 9 is a side view (partially in section) showing a conventional pulverized coal burner. The fuel nozzle 22 is connected to a carrier pipe (not shown) on the base side, and injects solid fuel together with primary air for carrier. On the outer periphery of the fuel nozzle 22, a secondary air nozzle 24 capable of forming a flow path 25 of secondary air (combustion air) is provided. On the outer periphery of the secondary air nozzle 24, a third air formation (combustion air) is provided. ) Flow path 26 tertiary air nozzle 27. The secondary air flow path 25 and the tertiary air flow path 26 communicate with the bellows 23. [0005] Viewed from the front of the burner outlet side: when the fuel nozzle 22, the secondary air nozzle 24, and the tertiary air nozzle 27 are located, it can be seen that the fuel nozzle 22 is the center, and the outer side is arranged concentrically. An annular secondary air nozzle 24 is provided, and an annular tertiary air nozzle 27 is also arranged concentrically on the outside of the secondary air nozzle 24. The tertiary air nozzle 27 is an air nozzle located at the outermost periphery. [0006] An ignition burner 21 penetrating the fuel nozzle 22 is provided inside the fuel nozzle 22, and the ignition burner 21 can be used to assist combustion when the burner is activated or is burned at a low load. A flame stabilizer 32 is provided at the front end of the outlet of the fuel nozzle 22 to expand the circulating flow 40 between the primary air and the secondary air. The partition wall of the tertiary air nozzle 27 is the partition wall of the throat of the burner constituted by the wall 9 of the stove 10. At the front end of the outlet of the secondary air nozzle 24, a guide member 33 that expands the tube in the radial direction with respect to the combustor central axis C is provided. The secondary air nozzle 24 is fixed by a support plate 35 attached to the outer wall of the fuel nozzle 22. [0007] The guide member 33 located at the front end of the secondary air nozzle 24 is mainly used to eject the tertiary air away from the center axis C of the burner toward the outside. In addition, a guide member 34 is provided in the tertiary air flow path 26. This guide member 34 is fixed by a support plate 36, and the other end of the support plate 36 is fixed on the outer wall of the secondary air nozzle 24. [0008] The secondary air flow and the tertiary air flow are ejected in a direction away from the central axis C side of the burner by using the guide members 33 and 34 in the secondary air nozzle 24 and the tertiary air nozzle 27. A circulating flow 40 is formed on its downstream side. In addition, the flame stabilizer 32 located at the front end of the outlet of the fuel nozzle 22 is used to expand the circulating flow 40. A high-temperature gas is trapped in the circulating flow 40, so the ignition of fuel particles will continue to progress, which can improve the stability of the flame. The fuel is held in a high-temperature and oxygen-deficient flame, so that the nitrogen component contained in the fuel is converted into a reducing agent such as ammonia or cyanogen and released, and then NO _{x is} reduced to nitrogen. The description of the burner having the above-mentioned structure can be found in the solid fuel burner described in Patent Document 1 below. [0009] In a combustion device such as a boiler having a plurality of solid fuel burners, the method of increasing the capacity of the burner is effective for reducing costs and improving the operability by reducing the number of burners. However, if the flames become larger as the burner capacity increases, the unfired area will expand. To expand the field of unfired, based means: a combustion time after ignition is shortened, will be insufficient to suppress the generation of NO _x, it is one of the causes of deterioration in combustion efficiency. [0010] Therefore, the invention of the burner disclosed in the following Patent Document 2 is to make the shape of the fuel nozzle into a flat shape so as to increase both the burner capacity and the cross-sectional area of the jet stream containing the fuel fluid. This reduces the flow rate and reduces the unfired distance of the fuel. [0011] In addition, the invention of the burner disclosed in the following Patent Document 3 is to improve the burner structure of the above Patent Document 2 and to make the cross-sectional shape of the fuel nozzle so that the flow path that reaches the venturi tube shrinks. Before the neck, it is rounded, and the flatness is gradually increased from the neck of the venturi to the opening of the nozzle, and the flatness is maximized at the opening. [0012] In addition, the invention of the burner disclosed in the following Patent Document 4 is an improvement of the burner structure of the above Patent Document 2 and a cross section of a secondary combustion gas (secondary air) nozzle located on the outer periphery of the fuel nozzle. The shape is a flat shape at the exit portion, and the cross-sectional shape of the tertiary combustion gas (tertiary air) nozzle located on the outer periphery of the secondary combustion gas nozzle is rounded at the opening portion of the furnace wall surface. This document discloses a structure in which a guide plate for tertiary combustion gas is provided in the tertiary combustion gas nozzle, and in the upper and lower portions of the outer periphery of the secondary combustion gas nozzle. [0013] According to the invention disclosed in the aforementioned Patent Document 2, since the unfired distance of the fuel can be reduced, the burning time after the fire can be secured. In addition, according to the invention disclosed in the aforementioned Patent Document 3, the flow path is expanded again after the flow path shrinks in the flow path of the venturi tube, and the flow path is enlarged again. Therefore, the fuel concentration of the fuel-containing fluid near the inner wall of the nozzle is increased. The distribution system is homogenized. [0014] By diffusing the combustion gas radially outward, the flame formed at the fuel nozzle outlet and the combustion gas such as tertiary air will not be immediately mixed together, and will form: The circulation area where a circulating flow is generated between the fuel jet and the peripheral air jet causes a phenomenon in which the gas in the furnace flows back to the side of the burner. In this field, because the combustion gas stays here, the oxygen concentration is very low, and the NO _x originally generated by the flame formed at the fuel nozzle outlet will be reduced in this field. In the following description, this field is referred to as the reduction field. [0015] In the low-NO _x burners, in order to facilitate reducing NO _x to nitrogen role must be formed near the burner and a high temperature air is insufficient to restore the art. According to the invention disclosed in the aforementioned Patent Document 4, the tertiary combustion gas flow path is divided into upper and lower parts, and air flowing through the upper and lower parts of the flow path is provided with different velocity components toward the upper and lower directions of the furnace, and flame generation biased to expand the field of reduction of NO _x, thereby seeking to be at low loads of the burner can be achieved even a low NO _x combustion. [Prior Art Document] [Patent Document] [0016] [Patent Document 1] Japanese Patent Application Publication No. 2006-189188 [Patent Document 2] International Publication No. 2008/038426 [Patent Document 3] Japanese Patent No. 5867742 [ Patent Document 4] Japanese Patent No. 5908091

[Technical Problem to be Solved by the Invention] According to the invention disclosed in the aforementioned patent documents and the like, the shape of the fuel nozzle is made flat to shorten it: from the ignition area of a jet surface containing a fuel fluid to the center of the jet As a result, the unfired area can be reduced. Thus, the effect of reducing _the NO _x concentration is high. [0018] Especially on the outer periphery of the outlet in the tertiary combustion gas nozzle located at the outermost side of the fuel nozzle, a guide member (for example, as shown in FIG. 9) is provided to expand the combustion gas radially outward. the guide member 34), to form the reduced art, can be used to reduce further the effect of improving the NO _x concentration. The burner described in Patent Document 4 discloses a structure in which a combustion air (air) can be guided to the outer peripheral side by providing a tertiary air guide plate on the outer peripheral portion of the secondary air nozzle. [0019] The guide member such as the aforementioned three air guide plate is supported and fixed on the outer wall of the secondary combustion gas nozzle located on the inside thereof, that is, on the fuel nozzle side (combustor center axis side). When performing burner maintenance, the fuel nozzle must be removed from the stove. At this time, the burner part including the guide member must be removed from the burner center shaft and taken out of the stove. The larger the part that must be removed and removed, the greater the work load during maintenance. [0020] In addition, considering factors such as manufacturing tolerances of the burner structure and deformation due to radiant heat of the flame, generally, the outer diameter of the guide member is made smaller than the diameter of the wall surface of the furnace opening. Slightly smaller. If the outer diameter of the guide member is made slightly smaller than the diameter of the wall surface of the furnace opening, the gap between the guide member and the wall surface becomes larger, so the ratio of the direct flow in the axial direction of the burner will be larger. The increase will destroy the circulation. Thus, the circulating flow will be reduced, so that the reduction will reduce the art, and will result in an increase of _the NO _x concentration danger consideration. [0021] The object of the present invention is to provide: an seeks to prevent an increase of _the NO _x concentration solid fuel burner, having: a will contain an outer periphery of the fluid fuel jet flow ejected combustion gas toward the radially outer It has a square diffuser structure and is easy to maintain. [Technical Solution to Solve the Problem] [0022] In order to achieve the technical problem of the present invention described above, it can be achieved by the following configuration. The invention described in the first patent application scope of the present application is a solid fuel burner, which is a solid fuel provided with a first gas nozzle (2), a second gas nozzle (4), and a third gas nozzle (7). The burner, the first gas nozzle (2), has a cylindrical flow path through which a mixed fluid of solid fuel and a carrier gas of the solid fuel flows, and the shape of the opening facing the wall surface of the furnace is flat; The two-gas nozzle (4) is composed of a first combustion gas that communicates with a bellows (3) that allows the combustion gas for the solid fuel to flow and is formed on the outer peripheral side of the first gas nozzle (2). The flow path (5) has a flat opening shape, and a first guide member (13) is provided on the outer periphery of the front end to guide the combustion gas from the center axis side of the burner to the outer periphery side; the third gas The nozzle (7) is configured as a second combustion gas flow path that communicates with the bellows (3) through which the combustion gas for the solid fuel can flow and is formed on the outer peripheral side of the second gas nozzle (4). (6) In addition, the shape of the opening is cylindrical. At the same time, the cross section passing through the central axis of the burner is composed of a horizontal portion (7a) along the central axis of the burner and an inclined portion that increases in diameter from the horizontal portion (7a) toward the furnace. (7b), wherein a second guide for guiding the combustion gas from the center axis side of the burner to the outer peripheral side is provided on the exit side of the second combustion gas flow path (6) And a support member (15) for supporting and fixing the second guide member (14) on an inner wall of the third gas nozzle (7). [0023] The invention described in the second patent application scope of the present application is directed to the solid fuel burner described in the first patent application scope, wherein the second guide members (14) are respectively provided in the second The upper and lower sides of the gas nozzle (4). The invention described in item 3 of the scope of patent application of the present case is directed to the solid fuel burner described in item 1 or 2 of the scope of patent application, wherein a part of the partition wall (18) of the aforementioned wind box (3) Is a plate-like member (17) provided to be separable from the partition wall (18), and the first gas nozzle (2) and the second gas nozzle (4) are manufactured to be separated from the plate-like member (17) ) Form a unitary structure. [0024] The invention described in item 4 of the scope of patent application for this case is directed to the solid fuel burner described in item 1 or 2 of the scope of patent application, wherein the front end of the first gas nozzle (2) is The outer periphery is provided with a flame stabilizer (12) formed around the first gas nozzle (2), and a projection surface of the flame stabilizer (12) from the furnace side to the nozzle side is connected to the second gas nozzle (4) ) At least part of the projection surface overlaps. [0025] Here, the "flat shape" means, for example, a rectangle shown in FIG. 5 (A), an ellipse shown in FIG. 5 (B), and a semicircle shown in FIG. 5 (C). A combination shape with a rectangle and a shape such as a wide polygon shown in FIG. 5 (D) are defined as having a flat shape having a long diameter and a short diameter, or a long side W and a short side H. In FIG. 5 (A), it may be acceptable that some or all of the four corners are curved. Similarly, in FIG. 5 (D), a part or all of the corners of the polygon may be curved. In addition, in each of the shapes described above, the curvature of the curved portion is not limited. [0026] (Action) At the exit side in the third gas nozzle located at the outermost side of the first gas nozzle, a guide member for the combustion gas, that is, the second guide member is used by the first guide member on its inner peripheral side. When the two gas nozzles are supported by the wall surface, the second guide member is fixed to the outer wall of the second gas nozzle. Therefore, it is not necessary to include the second guide from the central axis of the burner when performing burner maintenance. The structure including the components is removed and taken out of the furnace. [0027] Since the second guide member is supported by the inner wall of the third gas nozzle on the outer peripheral side, the portion to be taken out must be removed and reduced to the size of the second guide member from the center axis of the burner. Only the second gas nozzle on the inner side. [0028] Therefore, according to the invention described in the first aspect of the patent application scope of the present application, since the second guide member is supported from the outer peripheral side, it is not necessary to remove the second guide member when performing maintenance on the burner. Take out, so you only need to remove the removed part is small, maintenance and repair become easy. If the second guide member is supported from the inner peripheral side, factors such as the aforementioned deformation must be taken into consideration, and the outer diameter of the second guide member must be made slightly smaller, and the second guide member and the second guide member must be enlarged. Clearance of the wall surface of the stove opening. However, since the guide member is supported by its outer peripheral side, the gap between the second guide member and the wall surface can be made smaller, or the diameter of the second guide member can be made larger than the opening of the wall surface. Larger diameter. [0029] In addition, by providing a cylindrical third gas nozzle on the outer periphery of the flat first gas nozzle, the second combustion gas flow path mainly interposes the long diameter or the long side of the first gas nozzle. Because it is arranged above and below, compared with the case where the third gas nozzle is formed into a flat shape similarly to the first gas nozzle and the second gas nozzle, the mixing of combustion gas and fuel can be reduced, and the center of the burner can be enlarged Ministry of Reduction. [0030] In addition, the combustion gas flowing through a wider upper and lower flow path between the third gas nozzle and the second gas nozzle has higher straightness than the left and right sides. Therefore, according to the invention described in the second patent application scope of the present application, in addition to the role of the invention described in the first patent application scope, the second guide member is provided on the upper side of the second gas nozzle, respectively. As a result, it is possible to guide the combustion gas having a high directivity to the outside. [0031] In addition, a part of the partition wall of the bellows is manufactured as a plate-like member that can be separated from the partition wall body. Therefore, the burner can be easily removed and installed during maintenance. According to the invention described in item 3 of the scope of patent application in this case, in addition to the role of the invention described in item 1 or 2 of the scope of patent application, the plate-like member of the bellows partition wall and the burner Take out the removed part and make it into an integrated structure, so you don't need to disassemble the two separately, you can disassemble at the same time. [0032] In addition, the invention described in item 4 of the scope of patent application of the present application has the function of the invention described in item 1 or 2 of the scope of patent application, because it uses the first gas nozzle provided. The flame stabilizer on the outer periphery of the front end forms a circulating flow on its downstream side, and therefore has the effect of expanding the reduction range. [0033] In addition, when the nozzle side is viewed from the stove side, if the flame stabilizer and the exit partition wall of the second gas nozzle at least partially overlap, it is possible to prevent: the direction of the burner axis in the second gas nozzle The flow of the combustion gas on the surface goes straight toward the furnace, and therefore, it has the ability to efficiently form a stagnation area (reduction area) of the combustion gas on the downstream side of the flame stabilizer, and it is possible to reliably perform ignition. effect. [Effect of the invention] [0034] The solid fuel burner of the present invention, based low NO _x combustion can be achieved, can enhance the ease of repair. Specifically, the following effects can be achieved. According to the invention described in item 1 of the scope of patent application of the present application, the second guide member is supported by the inner wall side of the third gas nozzle on the outer peripheral side, and the second guide member and the third gas can be supported. The gap on the inner wall of the nozzle is made smaller to reduce the direct flow of the combustion gas passing through this gap in the direction of the burner axis. Therefore, to ensure that the burner outlet is formed in the recycle stream downstream of the size, and can form a sufficient reduction of the art, it is possible to achieve low NO _x combustion. In addition, when performing maintenance on the burner, it is only necessary to remove and take out the member on the inner peripheral side of the second guide member. Therefore, the part to be removed and taken out becomes very small, and the maintenance convenience is also better. . [0035] Furthermore, by providing a cylindrical third gas nozzle on the outer periphery of the flat first gas nozzle, the mixing amount of the combustion gas and the fuel can be reduced, and the reduction area of the central portion of the burner can be expanded. more facilitate low NO _x combustion. [0036] In addition, according to the invention described in the second patent application scope of the present application, in addition to the effects of the invention described in the first patent application scope, the invention also has a straight forward flow through the second combustion gas flow path. higher combustion gas, flows toward the outer guide, and therefore, can achieve lower NO _x in combustion. [0037] In addition, according to the invention described in item 3 of the scope of patent application, in addition to the effects of the invention described in item 1 or 2, the scope of application is because the invention can be separated from the bellows partition wall. Both the plate-shaped member and the removal and removal part of the burner are made into an integrated structure, and the two can be removed and installed together, making the maintenance convenience easier. In particular, the second guide member is supported by the inner wall side of the third gas nozzle. In this way, the movable portion during the removal and removal can be relatively small, and the size and weight of the plate-shaped member can be reduced. , Can also improve the convenience of maintenance. [0038] In addition, according to the invention described in item 4 of the scope of patent application, in addition to the effects of the invention described in item 1 or 2 of the scope of patent application, the invention provided in the first gas nozzle can also be used. The flame stabilizer at the outer periphery of the front end expands the reduction area, and the reduction area of the combustion gas can be effectively formed on the downstream side of the flame stabilizer, so the ignitability is better. Thus, can be reduced more _the NO _x concentration.

[0040] Embodiments of the present invention will be shown below. [Embodiment 1] [0041] FIG. 1 is a schematic side view showing a partial cross section of a solid fuel burner according to an embodiment of the present invention; FIG. 2 is a schematic view showing a partial cross section of the solid fuel burner of FIG. 1 Plan view; Figure 3 (A) is a front view of the solid fuel burner of Figure 1 viewed from the stove side; Figure 3 (B) is the arrow direction of the solid fuel burner of Figure 1 from the YY section line Observed section. [0042] The fuel nozzle (first gas nozzle) 2 is a cylindrical member whose base side is connected to a pipe 19 containing a fuel-containing fluid, and the inside thereof is constituted by a solid fuel and a carrier gas (in this embodiment) In the example, it is a flow path of a solid gas two-phase flow (mixed fluid) using air). In addition, the solid fuel is ejected together with the carrier gas. The solid fuel can be: coal (pulverized coal), solid such as biomass, powder, or a mixture of these substances. In this embodiment, the solid fuel is pulverized coal, and the carrier gas is air. The carrier gas flowing through the fuel nozzle 2 is also referred to as primary air, and the fuel nozzle 2 is also referred to as primary air nozzle. 2. [0043] A secondary air nozzle (second gas nozzle) 4 for forming a secondary air flow path 5 is provided on the outer periphery of the fuel nozzle 2, and a tertiary air flow path is provided for the outer air of the secondary air nozzle 4. 6 tertiary air nozzle (third gas nozzle) 7. These secondary air and tertiary air are combustion gases. As with the carrier gas described above, air is usually used. However, it is also possible to use exhaust gas, oxygen-rich gas, or at least one of these gases with air. Mixed gas and so on. In addition, the so-called secondary air and tertiary air of the secondary air and tertiary air are only used to distinguish them from the aforementioned primary air, and there is no substantial difference. [0044] When the fuel nozzle 2, the secondary air nozzle 4, and the tertiary air nozzle 7 are viewed from the front side of the burner outlet side (the stove 10 side), the fuel nozzle 2 is centered on the fuel nozzle 2 and is arranged concentrically on the outer side thereof. An annular secondary air nozzle 4 is provided, and an annular tertiary air nozzle 7 is arranged concentrically outside the secondary air nozzle 4. The tertiary air nozzle 7 is an air nozzle constituting the outermost periphery. [0045] Inside the fuel nozzle 2, an ignition burner (oil gun) 1 penetrating through the fuel nozzle 2 is provided, which is used to assist combustion when the burner is activated or during low-load combustion. A flame stabilizer 12 is provided at the front end of the outlet of the fuel nozzle 2 to increase the circulating flow between the primary air and the secondary air. This flame stabilizer 12 is arranged in a ring shape at the front end portion of the fuel nozzle 2, and a circulating flow can be formed on the downstream side of the flame stabilizer 12, which has the effect of improving ignitability and stabilizing the flame. In addition, a flame stabilizer 12 having a shark tooth-like protrusion may be used on the fuel nozzle 2 side. A burner without the flame stabilizer 12 is also included in the present embodiment. [0046] The ignition burner 1, the fuel nozzle 2, the secondary air nozzle 4, and the tertiary air nozzle 7 are formed from a stove opening provided on a stove wall (formed by a water pipe (not shown)) 9 of the stove 10. 8. The respective sprays are sprayed toward the inside of the furnace 10 respectively. These ignition burners 1, fuel nozzles 2, secondary air nozzles 4, and tertiary air nozzles 7 are arranged around the furnace opening 8 and supply pulverized coal or air from a combustion air flow path (not shown). Inside the air box 3 for combustion air. The partition wall 18 is a wall-like member for separating the internal space of the bellows 3 and the furnace outer 20, and the structure of the plate 17 before the fuel nozzle 2 is provided in the partition wall 18 is made from: The structure 18 is separately installed on the partition wall 18, and can be removed and taken out integrally with the fuel nozzle 2 when the burner is maintained and repaired. 4 is a side view showing an example of a connection structure between a front plate piece 17 and a partition wall 18. The plate 42 and the partition wall 18 integrally formed with the front plate 17 are respectively provided with holes, and the bolts 44 are inserted and buried in the holes and locked and fixed with the nuts 46, so that the front plate 17 can be installed in On the partition wall 18. In addition, it is not limited to the example shown in the figure, and other fixing mechanisms or locking mechanisms such as fixing with screws or hooks may be used. [0048] In addition, the pulverized coal flow path in the fuel nozzle 2 includes a concentrator 11 for concentrating pulverized coal particles on the inner wall side of the fuel nozzle 2 and spraying fuel into the furnace 10. The concentrator 11 is provided on the outer periphery of the ignition burner 1, and a cross section orthogonal to the axial direction of the pulverized coal flow path forms a reduced area and an enlarged area toward the inner wall of the fuel nozzle 2. The fuel is concentrated toward the inner wall side of the nozzle (the radial outer side of the central axis). It should be noted that a burner without the concentrator 11 is also included in the present embodiment. [0049] The secondary air nozzle 4 is supported and fixed by a flat plate-shaped support member 16 fixed to the outer wall of the fuel nozzle 2. In addition, the shape of the support member 16 is not particularly limited, and it is not limited to a case where the support member 16 is supported from the outer wall of the fuel nozzle 2 as long as it has a coupling relationship capable of forming an integrated structure with the fuel nozzle 2. [0050] At the front end of the outlet of the secondary air nozzle 4, there is provided a guide sleeve (first guide) that can expand the tube in a radial direction (shape that expands outward) relative to the central axis C of the burner. Member) 13, the secondary air nozzle 4 and the guide sleeve 13 have an integrated structure. The guide sleeve 13 is used to guide the air flow away from the center axis C of the burner and eject it outward. Further, in the tertiary air flow path 6, guide blades (second guides) for guiding the tertiary air are provided in areas where the widths of the upper and lower sides of the secondary air nozzle 4 are large. Component) 14. In addition, the relationship between the guide sleeve 13 and the guide blade 14 lies in that the projection surface of the guide sleeve 13 from the furnace 10 toward the partition wall 18 and the projection surface of the guide blade 14 do not overlap. Size relationship or the configuration relationship between the two. [0051] As shown in FIG. 3, the fuel nozzle 2 and the secondary air nozzle 4 have opening shapes having a flat shape in the furnace opening portion 8. By making the fuel nozzle into a flat shape, in order to shorten the distance from the center portion of the field of fire jets pass onto the surface of the fuel-containing fluid from the jet, can be reduced based unfired art, therefore, _the NO _x concentration can be reduced. In addition, the so-called flat shape refers to a combination of a rectangle as shown in FIG. 5 (A), an ellipse as shown in FIG. 5 (B), and a combination of a semicircle and a rectangle as shown in FIG. 5 (C). The shape such as a wide polygon as shown in FIG. 5 (D) is a flat shape having a long diameter and a short diameter, or a long side W and a short side H. [0052] The cross-sectional shape of the fuel nozzle 2 perpendicular to the central axis C of the burner is circular from the fuel-containing fluid pipe 19 to the vicinity of the front plate 17 (narrow part of the flow path), and from there to the furnace The section up to the opening 8 is monotonously enlarged horizontally from the center axis C of the burner to the outside and gradually increases the flatness. Therefore, the flatness at the furnace opening 8 becomes the maximum. shape. [0053] The flatness is defined as the ratio (W / H) of the long side W to the short side H. Therefore, the so-called gradually increasing flatness means that the ratio (W / H) of the long side W to the short side H of the cross section of the fuel nozzle 2 orthogonal to the central axis is gradually increased little by little. The maximum flat shape refers to the shape of the portion having the largest ratio (W / H) of the long side W to the short side H in the fuel nozzle 2. In the combustion process performed by this burner, the guide sleeve 13 at the front end of the outlet of the secondary air nozzle 4 and the guide vanes 14 in the tertiary air nozzle 7 are used to make the secondary air flow and the tertiary air flow from the combustion. The central axis of the burner is separated from the C side, so that a flow in which the jet containing the fuel fluid and the combustion gas are not mixed in the immediate vicinity of the burner can be formed. In this manner, such that the fuel accumulated in the high temperature and lack of oxygen to the flame, while reducing NO _x to nitrogen. [0054] In addition, the flame stabilizer 12 at the front end of the outlet of the fuel nozzle 2 is used to promote the formation of a circulating flow, that is, to reduce the pressure in the area on the downstream side, thereby forming a circulating flow that flows from downstream to upstream. Because high-temperature gas is trapped in this circulating flow, the ignition of fuel particles can be continuously advanced, and the stability of the flame can be improved. [0055] The tertiary air nozzle 7 is also considered to be a part of the furnace wall 9. The cross section of the tertiary air nozzle 7 passing through the central axis C of the burner is composed of a horizontal portion (a uniform diameter portion) 7a along the central axis direction of the burner and The inclined portion (the enlarged diameter portion) 7b formed on the stove 10 side has a cylindrical shape when viewed from the stove 10 side. The tertiary air flow path 6 is a flow path between the outer wall of the secondary air nozzle 4 and the tertiary air nozzle 7. The width of the left and right flow paths is narrow, and the width of the upper and lower flow paths is large. Thus, the tertiary air may be reduced and fuel mixing, it is possible to promote the low NO _x combustion. [0056] FIG. 6 (A) is a partial enlarged view showing the solid fuel burner in FIG. 1; FIG. 6 (B) is an example of a support structure for supporting the guide blade 14 by the support member 15. FIG. 7 is a perspective view showing an example of the guide vane 14. [0057] The guide vane 14 is supported and fixed by a support member 15 fixed to the inner wall of the tertiary air nozzle 7. In the example shown, the support member 15 is composed of an upper support member 15 a fixed to the inner wall of the tertiary air nozzle 7 and a lower support member 15 b fixed to the outer surface of the guide vane 14. The guide blade 14 can be fixed by joining the upper support member 15a and the lower support member 15b with the bolt 50 and the nut 52. [0058] As shown in FIG. 7 (A), the guide vane 14 is formed by: a flat plate-shaped introduction portion 14a and a meniscus-shaped enlarged portion 14b, wherein the introduction portion 14a is composed of: The flow is formed by a flat plate-shaped member with a parallel flow direction. The meniscus-shaped enlarged portion 14b can guide the tertiary air flow from the center axis C of the burner toward the radially outer side (upper or lower side). The diffused meniscus-shaped enlarged portion 14b extends toward the furnace 10 side. [0059] In addition, the shape of the guide vane 14, the outer wall of the secondary air nozzle 4, and the positional relationship with the tertiary air nozzle 7, the number, and the support form performed by the support member 15 are not limited. For the sake of illustration only. For example, the enlarged portion 14b may also adopt such a triangle or a quadrangle as shown in FIG. 7 (B) and FIG. 7 (C), and its shape is not limited. The present embodiment also includes an embodiment in which the introduction unit 14a is omitted. As for the support member 15, the guide vane 14 may be supported and fixed from the inner wall of the tertiary air nozzle 7 on the outer peripheral side. In addition, a guide vane 14 may be provided on the entire outer periphery of the secondary air nozzle 4. [0060] In the fuel nozzle shaped to a flat shape of the burner configuration from: role order to achieve low NO _x combustion of the outer nozzle periphery of the combustion air flow toward the outward side diffusion reached, the system has the following feature. The fuel nozzle 2 on the inner peripheral side has a wide shape with respect to the horizontal portion 7a of the cylindrical tertiary air nozzle 7 on the outer peripheral side. In other words, the shapes of the fuel nozzles 2 and the secondary air nozzles 4 at the furnace opening 8 are such that the width between the left and right sides is larger than the width between the upper and lower sides. For the air flow path 6, the width of the left and right flow paths must be narrowed. Therefore, in this area, there is less air flow, and the airflow spreading outward is weak. On the other hand, the width of the flow path above and below the tertiary air nozzle 7 is larger than the width of the left and right flow paths. Therefore, the flow rate is large. High, so it is not easy to spread outside. [0061] Therefore, it is necessary to sufficiently improve the effect of making the tertiary air flowing above and below the tertiary air flow path 6 diffuse outward, and the method of setting the guide vanes 14 above and below the tertiary air flow path 6 is very important. Effect. The enlarged portion 14b of the guide vane 14 is preferably a large portion. [0062] When the burner is maintained and repaired, and the fuel nozzle 2 is removed from the furnace 10, if the guide vane 14 is supported from the outer wall of the secondary air nozzle 4 on the inner peripheral side, it must be supported. The removed portion is a wide range from the burner center axis C to the guide vane 14. In this case, in consideration of various factors such as manufacturing tolerances of the burner structure and deformation due to radiant heat of the flame, it is necessary to make the outer diameter of the guide vane 14 smaller, and the guide vane 14 14 and the inner wall of the tertiary air nozzle 7 are made larger. [0063] However, the guide vane 14 is supported and fixed by the support member 15 not from the outer wall of the secondary air nozzle 4, but from the inner wall of the tertiary air nozzle 7. Therefore, it is necessary to remove the removed portion, as long as the narrow range from the central axis C of the burner to the secondary air nozzle 4 is sufficient. Therefore, the work during maintenance and repair will not increase the burden. Moreover, the gap S (FIG. 3 (A)) of the guide vane 14 and the tertiary air nozzle 7 can be made relatively small without considering the above-mentioned deformation and the like. That is, the enlarged portion 14b of the guide blade 14 can be made relatively large. By making the enlarged portion 14b of the guide vane 14 relatively large, the effect of diffusing the tertiary air flow to the outside can be enhanced. [0064] In addition, if the guide vane 14 is provided so that the end portion of the enlarged portion 14b that is farthest from the burner center axis C in the radial direction is located more outward than the horizontal portion 7a, the guide vane 14 is provided. The shape of the guide vane 14 may be set to the narrowing side. According to this structure, the effect of reducing the direct flow of air three times across the gap S is greatly changed. [0065] The above reasons, as to ensure that the size of the burner outlet is formed downstream of the recycle stream to form a sufficient reduction of the art, it is possible to achieve low NO _x combustion. The shape, number, and installation position of the support members 15 of the guide blade 14 are not particularly limited. For example, as shown in FIG. 3, two flat support members 15 may be provided one above the other, or one may be provided one above the other. If a plurality of supporting members 15 are used to support the guide vane 14, the supporting structure is relatively strong, but if the number is too large, it will become the resistance of the air flow. Therefore, the plane and the air flow can be kept parallel. It is advisable to arrange them at two levels, one above the other. For the use of the guide vanes 14 to impart a velocity component toward the tertiary air toward the vertical direction of the furnace 10, the flame is enlarged toward the art of NO _x reduction, then, even at low load of the burner, it can achieve low NO _x combustion. [0066] The fuel nozzle 2 is fitted to the front plate 17, because the front plate 17 is a plate-like member that can be attached to and detached from the partition wall 18, as long as the front plate 17 is removed from the partition wall 18, The structural bodies (including the concentrator 11, the flame stabilizer 12, and the guide sleeve 13) such as the ignition burner 1, the fuel nozzle 2, and the secondary air nozzle 4 can be removed simultaneously and integrally. [0067] In addition, the combination of the front plate 17 and the fuel nozzle 2 can be used: a fitting method, a method of using a bolt and a nut through a flange, and a method of directly bonding by welding. It does not limit the way it is combined. When the nut 46 (FIG. 4) that originally fixed the front plate 17 is removed, and then the front plate 17 is taken out toward the outer side of the furnace 20, the component integrated with it can be taken out. 8 shows the relationship between the fuel nozzle 2 and the front plate 17 of the solid fuel burner when viewed from the outside of the furnace 20. FIG. 8 (A) shows the case where the guide blade 14 is supported on the inner wall of the tertiary air nozzle 7 on the outer peripheral side thereof; FIG. 8 (B) shows the case where the guide blade 14 is supported on the inner peripheral side thereof The situation on the outer wall of the secondary air nozzle 4. [0069] During maintenance and repair of the burner, the fuel nozzle 2 must be taken out of the furnace 10. At this time, if the guide blade 14 is supported on the outer wall of the secondary air nozzle 4 on the inner peripheral side, the guide blade 14 is The removed part is a large range from the burner central axis C to the guide vane 14, so the front plate 17 must also be made larger (as shown in Figure 8 (B)). In addition, the burden on maintenance work is increased. However, if the guide vane 14 is the inner wall of the tertiary air nozzle 7 supported on its outer peripheral side, the portion to be removed and taken out is only smaller than the secondary air nozzle 4 from the burner central axis C to the secondary air nozzle 4 The range is sufficient, so the front plate 17 can be made smaller (as shown in FIG. 8 (A)). Therefore, not only the weight of the front plate 17 is reduced, but also the convenience of maintenance can be improved. [0070] In this embodiment, as shown in FIG. 6, the member with the largest diameter that is integrated and removed is taken out, so that the secondary air nozzle 4 outlet including the outlet of the secondary air nozzle 4 can be taken out integrally as shown in FIG. 6. The part including the guide sleeve 13 (the part below (inside) the dotted line L used to indicate the lower end of the guide blade 14), the size of the front plate 17 must be made to be greater than or equal to the guide sleeve The size of the projection area of 13 from the furnace 10 to the partition wall 18 side. [0071] A large number of piping and wiring, not shown, are arranged outside the furnace 20, and the components such as the fuel nozzle 2 and the front plate 17 are removed and taken out for maintenance and repair of the burner. Clearance must be ensured with these components. The clearance space is ensured, especially on the large-caliber burner after the capacity of the single machine is enlarged. [0072] Assuming that the member from the burner central axis C to the guide vane 14 is supported on its inner peripheral side (the fuel nozzle 2 side) and can be removed and taken out integrally, the front plate 17 must be made larger, and the possibility of interference and collision with piping and wiring not shown is high. In addition, if the piping and wiring are bypassed in order to avoid the above-mentioned interference and collision, the wiring will become very complicated, or the piping and wiring must be disassembled before they are removed. Re-connection work will be performed after the removed part has passed, which will cause poor workability. [0073] However, if it is not necessary to remove and remove the guide vane 14, only the secondary air nozzle 4 and the guide sleeve 13 on its inner peripheral side need to be removed and removed, the front plate 17 can be made accordingly. smaller. Therefore, the interference and collision of the front plate piece 17 with piping and wiring as described above hardly occur. [0074] During the maintenance and repair of the burner, the parts that need to be removed and removed can be as small as possible, and the maintenance convenience is also better. Figure 8 (A) shows the case where the front plate 17 is made into an oval shape, but it can also be made into a circle with a uniform diameter, a polygon such as a quadrangle, or other shapes, as long as it can fit the nozzle The shape of the largest diameter member is sufficient. [0075] In addition, although not shown, it may be provided on the inlet side of the tertiary air nozzle 7: an air swirling blade, which can generate a swirling flow to impart a swirling flow velocity to the tertiary air; or, a secondary air nozzle 4 The inlet side is provided with: an air flow regulator for adjusting the amount of secondary air. [0076] In addition, in the embodiment, although the example in which the tertiary air nozzle 7 is also regarded as a part of the furnace wall 9 is shown, the burner structure of this example can be made relatively simple, but the tertiary air nozzle 7 can also be made. Finish: Another cylindrical member separated from the furnace wall 9. [0077] In addition, if the projection surface of the flame stabilizer 12 from the furnace 10 side toward the fuel nozzle 2 side is at least partially overlapped with the projection surface of the guide sleeve 13, it can be prevented : The secondary air flow in the direction of the burner axis in the secondary air nozzle 4 is directed toward the furnace 10 and then directly passes therethrough. Therefore, a reduction area can be formed on the downstream side of the flame stabilizer 12 and the flame can be reliably caught. [Industrial Applicability] [0078] The present invention has the applicability that can be regarded as a burner device using solid fuel.

[0079]

1, 21‧‧‧Ignition burner

2, 22‧‧‧ fuel nozzle

3, 23‧‧‧ bellows

4, 24‧‧‧ secondary air nozzle

5.25‧‧‧secondary air flow path

6, 26‧‧‧three air flow paths

7, 27‧‧‧three air nozzles

7a‧‧‧Horizontal

7b‧‧‧inclined

8‧‧‧ Stove opening

9‧‧‧ fire wall

10‧‧‧ Stove (inside)

11‧‧‧ fuel concentrator

12, 32‧‧‧ Flame stabilizer

13‧‧‧Guide Sleeve

14‧‧‧Guide Blade

14a‧‧‧Introduction Department

14b‧‧‧Expansion Department

15‧‧‧Guide blade support member

16‧‧‧Guide sleeve support member

17‧‧‧ front plate

18‧‧‧ dividing wall

19‧‧‧ Fuel-containing fluid piping

20‧‧‧ Outside the furnace (side)

33, 34‧‧‧Guide members

35, 36‧‧‧ support plate

40‧‧‧Circulation

42‧‧‧ Plate

44, 50‧‧‧ bolt

46, 52‧‧‧ Nuts

[0039] Fig. 1 is a schematic side view showing a partial cross section of a solid fuel burner according to an embodiment of the present invention. FIG. 2 is a schematic plan view showing a partial cross section of the solid fuel burner of FIG. 1. FIG. 3 (A) is a front view of the solid fuel burner of FIG. 1; FIG. 3 (B) is a cross-sectional view of the solid fuel burner of FIG. 1 viewed from a direction of an arrow of a Y-Y section line. FIG. 4 is a side view showing a partial cross-section of an example of a connection structure between a front plate and a partition wall. (5) (A), (B), (C), and (D) of FIG. 5 are diagrams showing various cross-sectional shapes of the opening portion of the fuel nozzle of FIG. (6) FIG. 6 (A) is a partial enlarged view showing the solid fuel burner of FIG. 1; FIG. 6 (B) is a view showing an example of a supporting structure of a guide blade. FIG. 7 is a perspective view showing an example of the guide vane. Figure 8 shows the relationship between the fuel nozzle of the solid fuel burner and the front plate when viewed from outside the furnace. Figure 9 is a side view showing a partial cross section of a conventional pulverized coal burner.

Claims (4)

A solid fuel burner comprising a first gas nozzle, a second gas nozzle, and a third gas nozzle. The first gas nozzle includes a solid fuel and a carrier gas for the solid fuel. A cylindrical flow path through which the mixed fluid flows, and the shape of the opening facing the wall surface of the furnace is flat; The first combustion gas flow path on the outer peripheral side of the first gas nozzle has a flat opening shape, and at the same time, a first part for guiding the combustion gas from the center axis side of the burner to the outer peripheral side is provided on the outer periphery of the front end. A guide member; the third gas nozzle is constituted by a second combustion gas flow path which communicates with a bellows through which the combustion gas for the solid fuel can flow and is formed on the outer peripheral side of the second gas nozzle , And the shape of the opening is cylindrical, at the same time, its cross section through the central axis of the burner is: water along the direction of the central axis of the burner The solid fuel burner is formed by an inclined portion having an enlarged diameter from the horizontal portion toward the furnace. The solid fuel burner is characterized in that: On the exit side of the second combustion gas flow path, a solid fuel burner is provided for removing combustion gas The second guide member of the burner center axis is guided to the outer peripheral side, and a support member for supporting and fixing the second guide member is provided on the inner wall of the third gas nozzle. The solid fuel burner according to item 1 of the scope of patent application, wherein the second guide member is provided on an upper side and a lower side of the second gas nozzle, respectively. The solid fuel burner according to claim 1 or 2, wherein a part of the partition wall of the bellows is a plate-shaped member provided to be separated from the partition wall, and the first gas nozzle The second gas nozzle has a structure integrally formed with the plate-shaped member. The solid fuel burner according to claim 1 or claim 2, wherein a flame stabilizer formed around the first gas nozzle is provided on an outer periphery of a front end of the first gas nozzle, and the flame is stabilized. The projection surface of the device from the furnace side to the nozzle side overlaps at least a part of the projection surface of the second gas nozzle.