JP7086831B2 - How to assemble a combustion burner, boiler and combustion burner - Google Patents

Description

The present invention relates to a combustion burner, a boiler and a method for assembling a combustion burner.

A large boiler such as a coal-fired boiler has a hollow-shaped furnace installed in the vertical direction, and a plurality of combustion burners are arranged along the circumferential direction on the furnace wall. Further, in the coal-fired boiler, a flue is connected above the vertical direction of the furnace, and a heat exchanger for generating steam is arranged in this flue. Then, the combustion burner injects a mixture of fuel and air (oxidizing agent gas) into the fireplace to form a flame, and combustion gas is generated and flows into the flue. A heat exchanger is installed in the area where the combustion gas flows, and superheated steam is generated by heating the water or steam flowing in the heat transfer tube constituting the heat exchanger.

In order to realize low NOx combustion in the combustion burner, a splitter is installed on the side surface or the internal side of the fireplace of the combustion burner so that an internal flame holding is formed. By forming the internal flame holding, an ignition surface is formed in front of the splitter in which the fuel gas (air mixture of pulverized coal and primary air) is ejected toward the fireplace.

A plurality of splitters are provided so as to divide the fuel gas passage of the combustion burner into a plurality of parts, and a flame holder having an inclined surface is formed on the furnace side so that the fuel gas passage becomes narrower toward the tip. Internal flame retention is formed by the fuel gas branched on the inclined surface generating a swirl at the position of the vertical end surface on the furnace side of the inclined surface.

The splitter is formed with appropriate dimensions using stainless cast steel as a base material, and the surface where the fuel gas contacts is ceramic so that wear due to pulverized coal in the fuel gas is prevented and the dimensions of the stainless cast steel are maintained. Some tiles are pasted. The ceramic tile is fixed to the base metal by pins. In addition, since the end face of the flame holder on the furnace side is prone to oxidative thinning of pins due to the influence of high temperature atmosphere and atmospheric gas, the base metal is exposed to the inside of the furnace without attaching ceramic tiles.

In Patent Document 1 below, the wear-resistant member is provided in a portion where the wear-resistant member is easily worn to improve the durability, and the wear-resistant member is selectively arranged to reduce the trouble of providing the wear-resistant member at the time of maintenance. The technology is disclosed.

Japanese Unexamined Patent Publication No. 2017-145974

When the boiler is in normal operation, the fuel gas flowing through the combustion burner cools the splitter and keeps the temperature of the stainless cast steel base metal within the corrosion resistant temperature range. Therefore, oxidative corrosion is suppressed.

On the other hand, when the boiler is operating at a high load, maintenance may be performed on the mill on the fuel gas supply side. In this case, some combustion burners are extinguished and the flow of fuel gas is stopped. Further, when the boiler is operated at a low load, the boiler load is adjusted by extinguishing one of the combustion burners in a plurality of stages.

In these extinguished combustion burners, the flow of fuel gas is stopped, so that the temperature tends to rise due to the radiant heat from the fireplace. Cooling air may flow to prevent temperature rise, but since the purpose of the cooling air is to suppress the generation of NOx, the flow rate to the fuel burner is smaller than the fuel gas flow rate during normal operation. Will be supplied. Therefore, the base material of the splitter may not be sufficiently cooled and oxidative corrosion may occur, which causes a decrease in the strength of the base material. In addition, the pin for fixing the ceramic tile attached to the base material may rise in temperature due to the heat effect from the fireplace or the base material, causing oxidative corrosion, and the ceramic tile may fall off.

In order to prevent the temperature rise of the base material of the splitter, there is a method of arranging the splitter in the combustion burner away from the internal space of the furnace, but a sufficient cooling effect could not be obtained.

The present invention has been made in view of such circumstances, and is a method for assembling a combustion burner, a boiler, and a combustion burner capable of suppressing a temperature rise of a base material of a splitter and suppressing the occurrence of oxidative corrosion. The purpose is to provide.

In order to solve the above problems, the following means are adopted as the method for assembling the combustion burner, the boiler and the combustion burner of the present invention.
That is, the combustion burner according to the present invention has a fuel nozzle that ejects a fuel gas that is a mixture of fuel and an oxidant gas into the furnace, and a combustion air nozzle that blows the oxidant gas into the furnace from around the fuel nozzle. With respect to the flame holder, which is arranged in the fuel nozzle and whose width in the direction intersecting with the fuel gas flow direction becomes wider toward the end face of the fuel nozzle on the furnace side, and the flame holder. A rectifying unit arranged on an extension line on the upstream side in the fuel gas flow direction is provided, and the flame holder is provided on the base material and the base material, and is on the upstream side of the end face on the furnace side of the base material. It has an inclined surface formed from a position toward the end face of the fuel nozzle on the furnace side, and is connected to the inclined portion of the base material by being connected to the inclined portion formed so as to project from the end face of the base material on the furnace side. It has a cover portion that covers the end face on the furnace side, and the inclined portion and the cover portion are made of ceramics.

According to this configuration, the flame holder arranged in the fuel nozzle becomes wider toward the furnace side end face of the fuel nozzle, and therefore the fuel gas passage becomes narrower toward the furnace side end face, and the fuel nozzle becomes narrower. Internal flame retention is performed on the upstream side of the fuel gas from the end face on the furnace side. The flame holder has a base material, a ceramic inclined portion and a cover portion, and the inclined portion is provided on the base material.

The inclined portion has an inclined surface formed from a position upstream of the furnace side end face of the base metal toward the furnace side end face of the fuel nozzle, and is formed so as to project from the furnace side end face of the base metal. As a result, a flame holder is formed in which the width becomes wider toward the end face on the furnace side of the fuel nozzle, and the fuel gas passage becomes narrower toward the end face on the furnace side.

Further, since the tip of the inclined portion on the furnace side is arranged closer to the end face of the fuel nozzle on the furnace side than the end face of the base metal on the furnace side, the base metal and the connection portion where the inclined portion is connected to the base metal are on the furnace side. The temperature is relatively low compared to the tip of the sloping part on the furnace side. Therefore, the rise in the base metal temperature can be suppressed, and oxidative corrosion is unlikely to occur. The inclined portion is installed on the furnace side and is exposed to a high temperature atmosphere, but since it is made of ceramic, there is no risk of metal corrosion due to high temperature.

Further, the ceramic cover portion is provided so as to cover the end face of the base metal on the furnace side when the inclined portion is fixed to the base metal so that the base metal is not exposed to the furnace side. As a result, it is possible to suppress an increase in the temperature of the base metal and suppress the occurrence of oxidative corrosion.

In the above invention, the inclined portion and the cover portion may be integrally configured to form a surface material.

According to this configuration, the number of parts can be reduced, and the cover portion can be easily supported.

In the above invention, the inclined portion may be provided on the base material so as to project in two directions with the base material sandwiched between them.

According to this configuration, when fuel gas passages are formed on both sides of the splitter, internal flame holding can be generated on both sides in two directions with the flame holding device and the rectifying section sandwiched between them.

In the above invention, the inclined portion protruding in one direction of the inclined portions in two directions and the inclined portion protruding in the other direction may be formed separately.

According to this configuration, the thermal stress caused by mutual restraint due to the temperature rise of the inclined portion and the base metal is reduced, the flame holder can be prevented from being damaged, and the durability can be improved. Further, even if any of the inclined portions is damaged for some reason, the inclined portions can be easily replaced with respect to the base metal.

In the above invention, the inclined portion and the cover portion are integrally formed to form a surface material, and a gap is formed at an end portion of the two surface materials facing the cover portion. A surface material may be installed.

According to this configuration, even if there is a difference in the amount of heat elongation between the cover portion and the base metal due to the temperature rise, it is possible to prevent the generation of local stress due to the contact force between the cover portions and the cover portion. It is possible to prevent damage.

In the above invention, the inclined portion may be fixed to the base material by a metal fixing material.

According to this configuration, the metal fixing material fixes the inclined portion to the base material. The base metal and the fixing material that connects the base material and the inclined part are separated from the furnace side, and the temperature is relatively low compared to the tip of the inclined part on the furnace side. Therefore, the fixing material is made of metal. However, oxidative corrosion of the fixing material can be suppressed.

In the above invention, the surface material may be formed by being divided into a plurality of parts along a direction perpendicular to the fuel gas flow direction.

According to this configuration, even when there is a difference in the amount of heat elongation between the surface material and the base material in the direction perpendicular to the fuel gas flow direction due to the temperature rise, the thermal stress is dispersed and the surface material is damaged. Can be prevented and durability can be improved. Further, even if any of the surface materials is damaged for some reason, the damaged surface material can be easily replaced.

The boiler according to the present invention includes the furnace having a hollow shape and being installed along the vertical direction, the combustion burner according to any one of claims 1 to 5 arranged in the furnace, and the furnace. It is arranged in the upper part in the vertical direction of the above, and includes a flue through which the combustion gas generated by the combustion of the fuel gas in the combustion burner passes.

The method for assembling the combustion burner according to the present invention includes a fuel nozzle that ejects a fuel gas obtained by mixing fuel and an oxidant gas into the furnace, and combustion air that blows the oxidant gas into the furnace from around the fuel nozzle. For the nozzle, the flame holder arranged in the fuel nozzle, and the flame holder having a wider width in the direction intersecting with the fuel gas flow direction toward the furnace side end face of the fuel nozzle, and the flame holder. It is provided with a rectifying unit arranged on an extension line on the upstream side in the fuel gas flow direction, and the flame holding device is provided on the base material and the base material, and is on the upstream side of the end face on the furnace side of the base material. It has an inclined surface formed from the position of the fuel nozzle toward the end face on the furnace side of the fuel nozzle, and is connected to the inclined portion and is connected to the inclined portion formed so as to protrude from the end face on the furnace side of the base material. The inclined portion and the cover portion are a method of assembling a combustion burner made of ceramics, and the base material is more than the end face of the base material on the furnace side. It has a step of fixing the inclined portion so that the inclined surface is formed from a position on the upstream side toward the end face of the fuel nozzle on the furnace side and protrudes from the end face of the base metal on the furnace side.

According to the present invention, it is possible to suppress the temperature rise of the base material of the splitter and suppress the occurrence of oxidative corrosion.

It is a schematic block diagram which shows the coal-fired boiler which concerns on one Embodiment of this invention. It is a front view which shows the combustion burner which concerns on one Embodiment of this invention. It is a cross-sectional view which shows the combustion burner which concerns on one Embodiment of this invention, and is the AA line arrow view of FIG. It is sectional drawing which shows the splitter of the combustion burner which concerns on one Embodiment of this invention.

Hereinafter, preferred embodiments according to the present invention will be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to this embodiment, and when there are a plurality of embodiments, the present invention also includes a combination of the respective embodiments.

The boiler of the present embodiment uses pulverized coal pulverized coal as pulverized fuel (carbon-containing solid fuel), burns the pulverized coal with a combustion burner, and recovers the heat generated by this combustion to supply water, steam, and heat. It is a coal-fired (fine coal-fired) boiler that can be replaced to generate superheated steam. In the following description, the upper and upper sides indicate the upper side in the vertical direction, and the lower and lower sides indicate the lower side in the vertical direction.

In the present embodiment, as shown in FIG. 1, the coal-fired boiler 10 has a furnace 11, a combustion device 12, and a flue 13. The furnace 11 has a hollow shape of a square cylinder and is installed along the vertical direction. The furnace wall (heat transfer tube) constituting the furnace 11 is composed of a plurality of evaporation pipes and fins connecting them, and suppresses the temperature rise of the furnace wall by exchanging heat with water supply or steam.

The combustion device 12 is provided on the lower side of the furnace wall constituting the fireplace 11. In this embodiment, the combustion device 12 has a plurality of combustion burners (for example, 21, 22, 23, 24, 25) mounted on the furnace wall. For example, the combustion burners 21, 22, 23, 24, 25 are arranged at equal intervals along the circumferential direction as one set, and are arranged in a plurality of stages along the vertical direction. However, the shape of the furnace, the number of combustion burners in one stage, and the number of stages are not limited to this embodiment.

Each combustion burner 21, 22, 23, 24, 25 is connected to a crusher (mill) 31, 32, 33, 34, 35 via a pulverized coal supply pipe 26, 27, 28, 29, 30. Although not shown, the crushers 31, 32, 33, 34, 35 are supported, for example, in a housing so that a rotary table can be driven and rotated, and a plurality of rollers are linked to the rotation of the rotary table above the rotary table. It is rotatably supported and configured. When coal is thrown between a plurality of rollers and a rotary table, it is crushed to a predetermined size of pulverized coal and transported by a transport gas (primary air, oxidant gas) to a classifier (not shown). The classified pulverized coal can be supplied from the pulverized coal supply pipes 26, 27, 28, 29, 30 to the combustion burners 21, 22, 23, 24, 25.

Further, in the fireplace 11, a wind box 36 is provided at a mounting position of each combustion burner 21, 22, 23, 24, 25, and one end of an air duct 37 is connected to the wind box 36. The air duct 37 is provided with a blower 38 at the other end.

The flue 13 is connected to the upper part of the furnace 11 in the vertical direction. The flue 13 is provided with superheaters 41, 42, 43, reheaters 44, 45, and coal savers 46, 47 as heat exchangers for recovering the heat of the combustion gas, and is provided in the furnace 11. Heat exchange is performed between the combustion gas generated by combustion and the water supply and steam flowing through each heat exchanger.

A gas duct 48 through which the combustion gas that has undergone heat exchange is discharged is connected to the flue 13 on the downstream side thereof. The gas duct 48 is provided with an air heater (air preheater) 49 between the gas duct 48 and the air duct 37, and exchanges heat between the air flowing through the air duct 37 and the combustion gas flowing through the gas duct 48, and the combustion burners 21 and 22 , 23, 24, 25 can raise the temperature of the combustion air (oxidizing gas) to be supplied.

Further, the flue 13 is provided with a denitration catalyst 50 at a position upstream of the air heater 49. The denitration catalyst 50 supplies a reducing agent having an action of reducing nitrogen oxides such as ammonia and urea water into the flue 13, and the combustion gas to which the reducing agent is supplied reacts with the nitrogen oxides and the reducing agent. By promoting it, nitrogen oxides in the combustion gas are removed and reduced. The gas duct 48 connected to the flue 13 is provided with a soot dust treating device (electrostatic precipitator, desulfurization device) 51, an attracting blower 52, etc. at a position downstream of the air heater 49, and a chimney 53 is provided at the downstream end. ing.

On the other hand, in the pulverized coal fuel, when the crushers 31, 32, 33, 34, 35 are driven, the generated pulverized coal is combined with the transport gas (oxidizing agent gas), and the pulverized coal supply pipes 26, 27, 28, 29, 30 It is supplied to the combustion burners 21, 22, 23, 24, 25 through. Further, the heated combustion air is supplied from the air duct 37 to the combustion burners 21, 22, 23, 24, 25 via the air box 36. Then, the combustion burners 21, 22, 23, 24, 25 blow the pulverized fuel mixture in which the pulverized coal and the transport gas (primary air) are mixed into the fireplace 11 and the combustion air into the furnace 11, at this time. A flame can be formed by igniting. A flame is generated in the lower part of the furnace 11, and the combustion gas rises in the furnace 11 and is discharged to the flue 13.

After that, the combustion gas is heat-exchanged by the superheaters 41, 42, 43, the reheaters 44, 45, and the economizers 46, 47 arranged in the flue 13, and then the nitrogen oxides are reduced and removed by the denitration catalyst 50. Then, after the particulate matter is removed and the sulfur content is removed by the soot and dust treatment device 51, the gas is discharged from the chimney 53 into the atmosphere.

Next, the combustion burners 21, 22, 23, 24, 25 according to the present embodiment will be described with reference to FIGS. 2 to 4.
As shown in FIG. 2, the combustion burners 21, 22, 23, 24, 25 include a fuel nozzle 18, a combustion air nozzle 19, and the like. In this embodiment, the upper side and the lower side of the paper surface are described for convenience, and do not necessarily indicate the vertical upper side and the vertical lower side. In the actual usage mode of the combustion burner, the upper side of the paper surface is horizontal. You may turn to the direction.

The fuel nozzle 18 has a substantially rectangular cross section when viewed from the front. The fuel nozzle 18 ejects a fuel gas, which is a mixture of fuel and primary air (oxidizing gas), into the furnace 11. The combustion air nozzle 19 is provided around the fuel nozzle 18, and blows combustion air (secondary air, oxidizing gas) into the furnace 11. The combustion air mixes with the fuel gas ejected from the fuel nozzle 18 to promote combustion. Air is used as the oxidizing gas in this embodiment. It may have a higher oxygen ratio than air or a lower oxygen ratio than air, and can be used by optimizing the fuel flow rate.

A splitter 1 having a long tip surface in one direction is provided in the fuel nozzle 18 so that the fuel nozzle 18 is viewed from the front. As shown in FIG. 3, the splitter 1 is a plate-shaped member whose plate surface is arranged along the fuel gas flow direction. Further, as shown in FIG. 2, the splitter 1 is perpendicular to the flow direction of the fuel gas from one surface 18a side of the inner wall surface of the fuel nozzle 18 to the other surface 18b facing the one surface 18a. It is installed extending in the direction. Hereinafter, the direction perpendicular to the rectifying unit 4, that is, the length direction of the splitter 1 on the furnace side tip surface of the splitter 1 and the direction perpendicular to the flow direction of the fuel gas are referred to as the longitudinal direction of the splitter 1.

As shown in FIGS. 2 and 3, a plurality of splitters 1 are arranged in the fuel nozzle 18 in the direction perpendicular to the flow direction of the fuel gas and in the direction perpendicular to the longitudinal direction of the splitter 1. The plurality of splitters 1 are installed apart from each other, and a fuel gas passage is formed between the plurality of splitters 1. Further, a straightening vane 54 is installed between the plurality of splitters 1 in a direction intersecting the longitudinal direction of the splitter 1. The rectifying plate 54 is made of a metal such as stainless cast steel, and ceramic tiles are attached to the entire surface or a portion with a lot of wear to prevent wear due to pulverized coal contained in the fuel gas.

The splitter 1 is provided with a support plate 2 at the end in the longitudinal direction. By fixing the support plate 2 to the inner wall surface of the fuel nozzle 18, the splitter 1 is supported with respect to the fuel nozzle 18.

As shown in FIGS. 2 to 4, the splitter 1 has a flame holder 3 whose width increases toward the furnace side end surface 18A of the fuel nozzle 18 and an upstream side in the fuel gas flow direction with respect to the flame holder 3. It has a rectifying unit 4 arranged on an extension line of the above.

The flame holder 3 has a substantially triangular or trapezoidal cross-sectional shape, and has a shape in which the width of the cross section gradually widens toward the downstream side in the fuel gas flow direction. Here, the width of the flame holding device 3 is the length in the direction perpendicular to the longitudinal direction of the splitter 1 when the splitter 1 is viewed from the front.

The rectifying unit 4 is provided on the upstream side of the fuel gas flow of the flame holding device 3, and extends from the flame holding device 3 toward the upstream side. As shown in FIG. 4, the rectifying portion 4 is formed by attaching a plurality of ceramic tiles 15 to the entire surface of an exposed surface or a portion with a large amount of wear in order to prevent wear of the base material 5. Each of the plurality of ceramic tiles 15 is fixed to the base material 5 by a fixing material 16 such as a pin by stud welding or the like.

In the present embodiment, the flame holder 3 is made of a metal base material (for example, stainless cast steel), a ceramic (for example, alumina) surface material 6 provided on the base material 5, and a surface material 6 as a base material. It has a fixing material 7 made of metal (for example, made of stainless alloy) to be fixed to 5. Since the portion of the flame holder 3 that comes into contact with the fuel gas is made of ceramic, it has abrasion resistance against pulverized coal and the like contained in the fuel gas.

The fixing material 7 is, for example, a pin having a rod-shaped portion, one end side of which is in contact with the base material 5, and is fixed to the base material 5 by welding. The rod-shaped portion of the fixing material 7 is provided so as to penetrate the surface material 6. The fixing material 7 has, for example, a disk-shaped plate member provided on the other end side, and by sandwiching the surface material 6 between the plate member and the base material 5, the surface material 6 becomes the base material 5. On the other hand, fix it. For example, one fixing material 7 is installed for each surface material 6. Welding of the fixing material 7 and the base material 5 is performed by, for example, a stud welding method.

The upstream end of the base metal 5 is connected to the ceramic tile 15 forming the straightening vane 4. The downstream side of the base metal 5 has a substantially triangular or trapezoidal cross-sectional shape, and has a shape in which the width gradually increases toward the downstream side in the fuel gas flow direction. The cross-sectional shape of the downstream side of the base metal 5 does not necessarily have to be triangular or trapezoidal. When the cross-sectional shape of the base material 5 is triangular or trapezoidal and has an inclined surface, the inclined portion 8 is installed in parallel along the inclined surface of the base material 5. On the other hand, when the cross-sectional shape of the base material 5 has another shape such as a quadrangle, the inclined portion 8 has a shape corresponding to the outer shape of the base material 5.

The surface material 6 has an inclined portion 8 and a cover portion 9. The inclined portion 8 and the cover portion 9 are integrally formed, for example. When the inclined portion 8 and the cover portion 9 are integrally formed, the number of parts can be reduced, and the cover portion 9 is supported by the inclined portion 8, so that the structure is simplified. Further, since the cover portion 9 does not need to use the fixing material 7 which is a pin having a rod-shaped portion, there is no possibility that the fixing material 7 is oxidatively thinned in the cover portion 9 which becomes hot. The surface material 6 is produced by firing a ceramic material in the same manner as the ceramic tile 15 installed on the straightening section 4, the straightening plate 54, or the like. It is more desirable that the ceramic material of the surface material 6 of the flame holder 3 can withstand a temperature equal to or higher than that of the ceramic tile 15 installed in the rectifying unit 4 or the rectifying plate 54, and has the same or higher strength. .. For example, when the surface material 6 is made of alumina, it is more preferable that the surface material 6 has a higher purity of alumina than the ceramic tile 15 installed on the straightening unit 4, the straightening plate 54, or the like. As a result, the surface material 6 is installed on the furnace 11 side and is exposed to a high temperature atmosphere, but wear and damage are less likely to occur.

The surface material 6 is divided into a plurality of members along the longitudinal direction of the splitter 1. The divided surface materials 6 are arranged side by side along the longitudinal direction of the splitter 1. By forming the surface material 6 into a split structure, the thermal stress generated by the temperature rise is dispersed even when the mutual heat elongation amount in the longitudinal direction is different due to the temperature rise of the surface material 6 and the base material 5. , The splitter 1 can be prevented from being damaged, and the durability can be improved. Further, even if any of the surface materials 6 is damaged for some reason, the damaged surface material 6 can be easily replaced. The size of the surface material 6 is, for example, 100 mm to 300 mm in length along the flow direction of the fuel gas, and the length in the direction perpendicular to the flow direction of the fuel gas (the length in the longitudinal direction of the splitter 1). It is 20 mm to 50 mm.

The inclined portion 8 is, for example, a flat plate-shaped member having a plate thickness of about 10 mm to 20 mm, and has an inclined surface inclined with respect to the plate surface of the straightening portion 4 when the surface material 6 is fixed to the base material 5. As shown in FIG. 4, in the inclined portion 8, the base portion 8A on one end side is provided on the base material 5 by the fixing material 7, and the furnace side tip 8B side at the other end is formed toward the furnace side end surface 18A of the fuel nozzle 18. It has an inclined surface and is formed so as to protrude from the furnace side end surface 5A of the base metal 5. In the intermediate portion of the inclined portion 8, the cover portion 9 is provided so as to branch from the inclined portion 8 and is located on the furnace side of the furnace side end surface 5A of the base metal 5. Since the furnace side tip 8B of the inclined portion 8 is arranged closer to the furnace side end surface 18A of the fuel nozzle 18 than the furnace side end surface 5A of the base material 5, the base material 5 and the inclined portion 8 are connected to the base material 5. The connecting portion is separated from the furnace 11 side, and the temperature is relatively low.

The inclined portion 8 is provided on the downstream side of the base metal 5 so that the inclined surface is inclined with respect to the flow direction of the fuel gas. As a result, the flame holder 3 whose width becomes wider toward the furnace side end face 18A of the fuel nozzle 18 is formed, and the fuel gas passage becomes narrower toward the furnace side end face 18A. The fuel gas is swirled on the furnace side tip 8B side of the inclined portion 8, so that an internal flame holding is formed. The inclined portion 8 of the surface material 6 is installed on the furnace 11 side and is exposed to a high temperature atmosphere, but since it is made of ceramic, there is no risk of oxidative corrosion due to high temperature.

The base portion 8A arranged on the upstream side of the inclined portion 8 is fixed to the base material 5 by the fixing material 7. By fixing the inclined portion 8 to the base material 5 only on the upstream side of the inclined portion 8, the length of the base material 5 in the fuel gas flow direction can be shortened, and the base material 5 can be used in the furnace of the fuel nozzle 18. It is not necessary to provide up to the side end surface 18A side.

The base 8A and the base material 5 of the inclined portion 8 are separated from the furnace 11 side, and the temperature is relatively lower than that of the tip 8B on the furnace side of the inclined portion 8. Therefore, oxidative corrosion of the base material 5 and the fixing material 7 can be suppressed, and the durability of the splitter 1 can be improved. For example, when one of the combustion burners 21, 22, 23, 24, 25 is extinguished and the internal fuel gas flow is stopped, or when the combustion burners 21, 22, 23, 24, 25 are igniting the burner. Even when the cooling air is circulated in an amount smaller than the fuel gas flow rate of the above, it is possible to suppress the temperature rise of the base material 5 and the fixing material 7 to a high temperature, and it is possible to suppress the occurrence of oxidative corrosion.

The cover portion 9 is, for example, a plate-shaped member, and is provided so as to cover the furnace side end surface 5A of the base material 5 along the furnace side end surface 5A of the base material 5. The cover portion 9 is connected to the inclined portion 8 and is integrally formed. The ceramic cover portion 9 is provided so that the metal base material 5 is not exposed to the furnace 11 side when the surface material 6 is fixed to the base material 5. As a result, the temperature rise of the base material 5 and the fixing material 7 can be suppressed, and the occurrence of oxidative corrosion can be suppressed. It is desirable that the cover portion 9 and the furnace side end surface 5A of the base metal 5 are arranged so as to form a gap.

The connecting portion between the inclined portion 8 and the cover portion 9 is provided at a position close to the base material 5. Therefore, the temperature rise of the connection portion between the inclined portion 8 and the cover portion 9 can be suppressed as compared with the case where the connecting portion is provided on the furnace side tip 8B side close to the furnace 11, and the connecting portion by the inclined portion 8 and the cover portion 9 can be suppressed. It is possible to suppress the occurrence of breakage in the bent shape of.

The inclined portions 8 may be installed on both side surfaces of one base material 5 so as to project in two directions with the base material 5 sandwiched between them. As a result, when fuel gas passages are formed on both sides of the splitter 1, internal flame holding can be generated on both sides in two directions with the rectifying unit 4 of the splitter 1 sandwiched between them.

As shown in FIG. 4, when the inclined portion 8 projects in two directions with the base material 5 interposed therebetween, the surface material 6 having the inclined portion 8 protruding in one direction among the two inclined portions 8 and the like. The surface material 6 having the inclined portion 8 protruding in the direction of is formed separately. The two surface materials 6 are installed so as to sandwich the base material 5 from both sides. As a result, if any of the surface materials 6 is damaged for some reason, the surface material 6 can be easily replaced with the base material 5. In the surface material 6, the portions where the ends of the two cover portions 9 face each other are installed so that a gap 9a is formed before the temperature rises. As a result, even when there is a difference in the amount of heat elongation between the cover portion 9 and the base material 5 due to the temperature rise, it is possible to suppress the generation of local stress due to the contact force with each other. It is desirable that the gap 9a is not too wide so that the base material 5 does not have a large temperature rise due to the influence of radiant heat from the furnace 11 side.

The surface material 6 divided into two is formed symmetrically with respect to the center line along the longitudinal direction of the splitter 1. By making the divided surface materials 6 have the same shape, the number of types of parts to be manufactured can be reduced. Further, it is possible to suppress bias due to thermal elongation when the temperature rises, for example, deformation in which one divided surface material 6 thermally expands more than the other divided surface material 6.

According to the above-described configuration, the furnace side tip 8B side of the inclined portion 8 and the cover portion 9 have a substantially U-shaped cross section perpendicular to the longitudinal direction of the splitter 1, and the base material 5 is formed from the furnace side tip 8B of the inclined portion 8. Since it has a concave shape between the furnace side end face 5A of the base metal 5 and the furnace side end face 5A of the base metal 5 from the furnace side tip 8B of the inclined portion 8, the solid wall thickness structure is filled with the ceramic material. It is possible to reduce the weight as compared with the case of having.

Further, the surface material 6 is formed by being divided into a plurality of parts in a fuel gas flow direction and a direction perpendicular to the rectifying portion 4 (longitudinal direction of the splitter 1). As a result, even when the temperature rise of the surface material 6 and the base material 5 causes a difference in the amount of mutual heat elongation in the direction perpendicular to the fuel gas flow direction, the thermal stress is dispersed and the surface material 6 Damage can be prevented and durability can be improved. Further, even if any of the surface materials 6 is damaged for some reason, the damaged surface material 6 can be easily replaced.

Further, as shown in FIG. 3, the tip portion of the surface material 6, that is, the furnace side tip 8B of the inclined portion 8, is located upstream of the furnace side end surface 18A of the fuel nozzle 18 in the fuel nozzle 18 on the upstream side of the fuel gas flow. It is preferably arranged so that it is located. As a result, the base material 5 can be kept away from the inside of the furnace 11, and the temperature rise of the base material 5 and the fixing material 7 can be further suppressed.

As described above, according to the present embodiment, the flame holder 3 has a metal base material 5 and a ceramic (for example, alumina) surface material 6 provided on the base material 5, and is in contact with the fuel gas. Since the part to be used is made of ceramic, it has wear resistance. The surface material 6 has an inclined portion 8 and a cover portion 9, and the furnace side tip 8B side of the inclined portion 8 is arranged closer to the furnace side end surface 18A of the fuel nozzle 18 than the furnace side end surface 5A of the base material 5. The base material 5 and the connection portion where the inclined portion 8 is connected to the base material 5 are separated from the furnace 11 side, and the temperature is relatively lower than that of the furnace side tip 8B of the inclined portion 8. Therefore, oxidative corrosion of the base material 5 can be suppressed. The inclined portion 8 is installed on the furnace 11 side and is exposed to a high temperature atmosphere, but since it is made of ceramic, there is no risk of oxidative corrosion due to high temperature.

Further, the ceramic cover portion 9 is provided so as to cover the furnace side end surface 5A of the base material 5 when the surface material 6 is fixed to the base material 5 so that the metal base material 5 is not exposed to the furnace 11 side. Be done. As a result, the temperature rise of the base material 5 can be suppressed, and the occurrence of oxidative corrosion can be suppressed. Further, the metal fixing material 7 fixes the inclined portion 8 to the base material 5. Since the base metal 5 and the fixing material 7 connecting the base metal 5 and the inclined portion 8 are separated from the furnace 11 side and have a relatively low temperature as compared with the furnace side tip 8B of the inclined portion 8, the fixing material 7 Even if it is made of metal, oxidative corrosion of the fixing material 7 can be suppressed.

In the above-described embodiment, the boiler of the present invention is a coal-fired boiler, but the solid fuel may be a boiler using biomass, petroleum coke, petroleum residue, or the like. Further, the fuel can be used not only for solid fuel but also for oil-fired boilers such as heavy oil, and gas (by-product gas) can also be used as fuel. It can also be applied to co-firing of these fuels.

Further, the present invention is applicable to a flame holder arranged in the fuel nozzle, and the structure in the fuel nozzle 18, that is, the position, size, and number of the splitter 1 and the rectifying plate 54 are the same as those described above. Not limited.

1: Splitter 2: Support plate 3: Flame holder 4: Rectifier 5: Base material 6: Surface material 7: Fixing material 8: Inclined part 8A: Base 8B: Tip 9: Cover part 9a: Gap 10: Coal-fired boiler 11: Fireplace 12: Combustion device 13: Smoke path 18: Fuel nozzle 19: Combustion air nozzle 21,22,23,24,25: Combustion burner 26,27,28,29,30: Pulverized coal supply pipe 31,32 , 33, 34, 35: Crusher 36: Air box 37: Air duct 38: Blower 41, 42, 43: Superheater 44, 45: Reheater 46, 47: Coal saver 48: Gas duct 49: Air heater 50: Denitration catalyst 51: Soot and dust treatment device 52: Induction blower 53: Chimney 54: Combustion plate

Claims (9)

A fuel nozzle that ejects fuel gas, which is a mixture of fuel and oxidizer gas, into the furnace,
A combustion air nozzle that blows oxidant gas into the furnace from around the fuel nozzle,
A flame holder that is arranged in the fuel nozzle and whose width in the direction intersecting with the fuel gas flow direction becomes wider toward the end face of the fuel nozzle on the furnace side.
A rectifying unit arranged on an extension line on the upstream side in the fuel gas flow direction with respect to the flame holding device,
Equipped with
The flame holder is
With the base material,
It has an inclined surface provided on the base metal and formed from a position upstream of the furnace side end face of the base metal toward the furnace side end face of the fuel nozzle, and protrudes from the furnace side end face of the base metal. And the inclined part formed by
A cover portion that is connected to the inclined portion and covers the end face of the base metal on the furnace side,
Have,
A combustion burner whose inclined portion and the cover portion are made of ceramics. The combustion burner according to claim 1, wherein the inclined portion and the cover portion are integrally formed to form a surface material. The combustion burner according to claim 1, wherein the inclined portion is provided on the base material so as to project in two directions with the base material sandwiched between the base materials. The combustion burner according to claim 3, wherein the inclined portion protruding in one direction and the inclined portion protruding in the other direction are formed separately from the inclined portions in two directions. The inclined portion and the cover portion are integrally formed to form a surface material.
The combustion burner according to claim 4, wherein the surface material is installed so as to form a gap at an end portion of the two surface materials facing the cover portion. The combustion burner according to claim 1, wherein the inclined portion is fixed to the base material by a metal fixing material. The combustion burner according to claim 2 or 5, wherein the surface material is formed by dividing the surface material into a plurality of pieces along a direction perpendicular to the fuel gas flow direction. The fireplace, which has a hollow shape and is installed along the vertical direction,
The combustion burner according to any one of claims 1 to 7 arranged in the furnace, and the combustion burner.
A flue located at the upper part in the vertical direction of the fireplace and through which the combustion gas generated by the combustion of the fuel gas in the combustion burner passes.
Boiler equipped with. A fuel nozzle that ejects fuel gas, which is a mixture of fuel and oxidizer gas, into the furnace,
A combustion air nozzle that blows oxidant gas into the furnace from around the fuel nozzle,
A flame holder that is arranged in the fuel nozzle and whose width in the direction intersecting with the fuel gas flow direction becomes wider toward the end face of the fuel nozzle on the furnace side.
A rectifying unit arranged on an extension line on the upstream side in the fuel gas flow direction with respect to the flame holding device,
Equipped with
The flame holder is
With the base material,
It has an inclined surface provided on the base metal and formed from a position upstream of the furnace side end face of the base metal toward the furnace side end face of the fuel nozzle, and protrudes from the furnace side end face of the base metal. And the inclined part formed by
A cover portion that is connected to the inclined portion and covers the end face of the base metal on the furnace side,
Have,
The inclined portion and the cover portion are a method of assembling a combustion burner made of ceramics.
With respect to the base metal, the inclined surface is formed from a position upstream of the furnace side end face of the base metal toward the furnace side end face of the fuel nozzle, and is formed so as to protrude from the furnace side end face of the base metal. A method of assembling a combustion burner having a step of fixing the inclined portion so as to be.

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